Atlas of Cardiac Surgery 9783031431944, 9783031431951

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Springer Surgery Atlas Series Series Editors: J. S. P. Lumley · James R. Howe

Francis C. Wells Editor

Atlas of Cardiac Surgery

Springer Surgery Atlas Series Series Editors J. S. P. Lumley James R. Howe

Francis C. Wells Editor

Atlas of Cardiac Surgery

Editor Francis C. Wells Department of Cardiothoracic Surgery Papworth Hospital Cambridge, UK

ISSN 2626-9015     ISSN 2626-9023 (electronic) Springer Surgery Atlas Series ISBN 978-3-031-43194-4    ISBN 978-3-031-43195-1 (eBook) https://doi.org/10.1007/978-3-031-43195-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Paper in this product is recyclable

Foreword

It is a pleasure to provide the Foreword for this splendid Cardiac Surgical Atlas, particularly as many of the contributors were former colleagues of mine, at the now Royal Papworth Hospital. The content is comprehensive and reflects the experience and meticulous approach the contributors brought to their task. Any surgeon contemplating an operation must feel confident of the anatomy that will be encountered. This Atlas is an excellent reference work designed to provide this. It should therefore find space in any cardiac surgical library. Oxford, UK

Terence English

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Preface

Cardiac surgery is a comparatively young speciality having its meaningful origins in the second half of the twentieth century. It is a speciality heavily dependent upon and integrated with bioengineering. The technology involved is extensive, critical and constantly developing. Without the steady development of materials, technology and prostheses, surgery of the heart would not have reached the levels of safety now routinely achieved internationally. Few conditions cannot be treated successfully in the modern world. To achieve this, the surgeon must have a dexterity of hand and mind allied with a sound knowledge of physiology, anatomy and embryology. Cardiac surgery is a team endeavour. The environment of the operating theatre is more akin to an orchestra than a solo effort. The surgeon must act as an interpreter and conductor carrying the ultimate responsibility for the patient; the players ensure the outcome. The integrated skills and knowledge base of the perfusionist, anaesthetist, nurses and assistants are vital for routine success. In this Atlas, we have endeavoured to provide an illustration of the basic surgical procedures as performed by the current team of surgeons at the Royal Papworth Hospital, a place where innovation, excellence and education are at the forefront of all that we do.

A Short History of the Evolution of Cardiac Surgery Surgery of the heart and of the brain are two of the last big conceptual developments in the history of the surgical profession. For cardiac surgery to develop in a meaningful way, there has had to be a deeply integrated approach with the biotechnology industry and deep understanding of the physiology of the cardiovascular system and haematology, in particular the science of blood rheology and clotting. In this brief review, I have concentrated on the earliest phases of development of the speciality as much of it is unknown by the modern trainee and has slipped into the mists of medical history. I have not expanded on the more modern techniques and technology as this will be within the purview of contemporary teachers and our younger colleagues. The earliest operations on the heart that carried some degree of success were those for cardiac trauma. First among these was done by Ludwig Rehn, a senior surgeon at Frankfurt City Hospital, a surgeon known for his willingness to innovate. On September 7th in 1896, Rehn was presented with a 22-year-old gardener’s assistant, Wilhelm Justus, who had been attacked by a stranger with a knife and stabbed between his fourth and fifth ribs. Faced with a decision between allowing the young man to die of cardiac tamponade or an attempt at surgical closure of the cardiac wound, Rehn elected to attempt repair. On opening the pericardium and draining the intrapericardial blood, he was able to find the small incision in the right ventricle and to close it with three interrupted sutures. It was a success, and Wilhelm regained consciousness 2 h later. The importance of this singular success began the process of undoing the words of the great Viennese surgeon, Theodor Billroth, who stated, “A surgeon who tries to suture a heart wound deserves to lose the esteem of his colleagues”. His English contemporary Stephen Paget stated, “Surgery of the heart has probably reached the limits set by Nature to all surgery:

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no new method and no new discovery can overcome the natural difficulties that attend a wound of the heart”. Until the advent of effective antibiotics, group C streptococcal pharyngitis induced an autoimmune disorder referred to as rheumatic fever. The brain and the heart were frequently affected producing choreoathetosis (St. Vitus dance) and myocarditis, which was accompanied by a valvulitis which scarred the heart valves in the following order of frequency: aortic, mitral, tricuspid and very occasionally pulmonary. The first to associate heart disease with rheumatic fever was David Pitcairn, a Scottish physician working at St. Bartholomew’s Hospital, London, in 1788. In 1812, William Charles Wells strengthened the association. In 1898, London physician Daniel Samways in a paper in The Lancet predicted that “one day mitral stenosis, a narrowing of the mitral valve caused by rheumatic vegetations, might be relieved by simply notching the mitral valve and leaving the atrium to continue with its defence”. The word vegetation was used likening the clumps of inflammatory tissue on the valve to the small florets of some vegetables such as broccoli. Four years later, the English surgeon, Sir Thomas Lauder Brunton, came to the same conclusion. He noted that at post-mortem, the damaged valve was easy to open with a scalpel. This was met with derision in much of the medical community. Interestingly, Rehn wrote that the heart valves were “out of bounds”! Some surgeons in France tried primitive closed procedures but without good effect. The problem was the inability to see inside the heart. In the early 1920s, Evarts Graham with Duff Allen made a “cardioscope” in an attempt to look inside the chambers of the heart. As can be imagined, little could be seen. They attached a little knife to it with a view to cutting the fused mitral valve. It was a failure. In Boston, Elliott Cutler attempted crude valvotomy plunging a knife through the ventricular wall, poking it about until it met resistance from what was thought to be the mitral valve and making incisions in what were thought to be the mitral commissures. There were no survivors from nine attempts. In 1925, Henry Souttar, surgeon at the London hospital and engineer by previous training, approached the valve differently. Operating on a young woman, he inserted his finger through a small incision through the left atrial appendage and was able to form a mental image of the valve at his fingertip. The patient had significant mitral regurgitation, and he could sense it. He therefore abandoned his idea of incising the mitral commissures and simply pushed his finger through the orifice. Following a stormy recovery, the patient survived. Objective improvement could not be found, and therefore, accompanied by the refusal of physicians to refer any more patients, his work in this area ceased. These events brought attempts at surgical correction to an end for two decades. Dwight Harken, a young Boston surgeon, had also been interested in the possibility of a surgical solution to rheumatic mitral stenosis. However, with the onset of World War II, he was despatched to London as a military surgeon. On arrival, he was confronted with many patients with shrapnel wounds to the chest, penetrating the heart and pericardium. He watched, unable to help, as most of those young men died, needlessly, he thought. He wrote of his amazement that surgeons of skill and experience would not touch the heart as though it was some mysterious organ. With careful planning, he set about, following the lead of Rehn, a programme of surgical shrapnel removal and cardiac repair. He succeeded in removing 134 missiles from the heart and great vessels of wounded soldiers with no deaths [1]. In 1948, following the great success of his military surgery, Dwight Harken returned to his interest in surgery of the rheumatic heart and tried to relieve mitral stenosis with a valvulotome, as Evarts Graham had suggested, with some success. In Philadelphia, Charles Bailey had been trying with little success. At about the same time, Lord Russell Brock had been doing similar work in London at Brompton Hospital. By 1952, Brock reported 100 operations with excellent results. In 1954, Charles Dubost invented a dilator specifically for the valve as did Oswald Tubbs and Brock in London. These instruments, which were inserted through the left atrial appendage to access the mitral valve and the left ventricular apex to access the aortic valve, were very successful and helped many people. Overstretching of the valve would produce valve regurgitation, which could be fatal, and so experience was invaluable in achieving regular success. Valvotomy was

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adopted around the world and, in particular in Third World countries, continues to offer help where the more expensive programmes of open-heart surgery are unaffordable [2]. The modern adaptation of this technique is percutaneous balloon valvotomy. Further and more refined surgical management awaited the ability to support the heart and lungs artificially. Development was directed in two main ways. For children who needed the correction of congenital defects, the American pioneer Walt Lillehei proposed an idea that reproduced the situation in the womb with the heart of the mother or, in several cases, the father to provide the propulsion required for blood flow of the infant (Fig. 1). These were the cross-circulation procedures. Mother or father was connected by simple tubing from the femoral artery and vein to the child’s circulation (Fig. 2). Lillehei achieved great success with this courageous approach and was able to report excellent results at 20 years [3]. This was truly groundbreaking in paediatric cardiac surgery, but of no use for an adult with cardiac disease. For adult cardiac surgery to develop, it would be necessary to be able to stop the heart and replace it and the lungs with mechanical support. John Gibbon had been working on this concept since the 1930s. For it to be possible, manipulation of the clotting mechanism had to be worked out. Charles Best, the discoverer of insulin, had begun to work with heparin as an anticoagulant. Together with the work of Gordon Murray, they were able to demonstrate that the clotting of the blood could be meaningfully delayed with refined heparin. In 1935, Murray injected heparin into a patient, which delayed the clotting time from 8 to 30 min. Working with his wife Mary, the Gibbons steadily developed their heart and lung machine and by 1935 were able to sustain a cat for almost 4 h. His work was interrupted for 4 years when he insisted on enlisting for military service. By 1954, he felt he had a machine that was fit for purpose, but many failures continued to occur, which were compounded by inaccurate or simply wrong diagnoses, and the surgeon regularly did not know what they were going to find at surgery. In parallel with these developments, Wilfred Bigelow in Toronto had been working on the idea of using profound hypothermia for protection and operating on the still, cold heart. Henry Swan in Denver was the first to use profound hypothermia in a significant number of cases with any degree of success. However, he admitted that these were very nerve-wracking operations, which depended so much on speed and accurate diagnoses, which was not always the

Fig. 1  Dr. Walton Lillehei and the scene in the operating theatre during a cross-circulation operation. All the attention is focussed on the child. The parent is on a table next to the one in the image with simply an anaesthetist and nurse standing by (UAB Archives, University of Alabama at Birmingham)

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Fig. 2  The set-up for cross-circulation showing the cannulation of the parent and child with the bubble filter and augmenting pump in line with the circulation, and inset shows the placement of the cannulae and the defect to be corrected

case. The technique allowed success with atrial septal defect closure and easy ventricular defects but was still limited in its application. Once again, Lillehei was in the frame developing the DeWall-Lillehei bubble oxygenator. In this device, oxygen was bubbled into the blood. A separating chamber allowed most of the bubbles to be removed. A heat exchanger was necessary to prevent the blood from cooling too much before being returned to the body. This machine was used initially and successfully by Lillehei in VSD closure. A true great of cardiac surgery, in fact in many ways the father of the speciality, Walt Lillehei fell from grace in his mid-50s. His reputation as a surgical great was resuscitated by an enormously generous gesture from Dr. John Kirklin, who, in front of the entire audience of the American Association for Thoracic Surgery, drew him to his feet to a warm and standing ovation of more than a thousand pairs of surgical hands (Fig. 3). By 1955, John Kirklin, working at the Mayo Clinic, built a Gibbon machine under licence paying enormous attention to detail, and finally he was able to complete a significant number of cases successfully. This demonstration of the practical application of the cardio-pulmonary bypass machine opened the door for the rapid expansion of the speciality. Though it would be several years before the problems of haemolysis, renal failure and post-pump syndrome would be fully understood and resolved. Kirklin played a large part in all of these developments and in particular demonstrated the importance of complement activation by the passage of blood across the artificial surfaces of the piping in the machine. Post-pump lung was a very significant problem with many patients remaining ventilator dependent post-operatively and several dying with adult respiratory distress syndrome.

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Fig. 3  Dr. John Webster Kirklin (1917–2004) (UAB Archives, University of Alabama at Birmingham)

In 1956, Dr. Wilhelm Kolf, who had already developed the renal dialysis machine, developed a membrane oxygenator, which was to be the basis of the future in oxygen transfer systems, being far less traumatic on the blood. At that time, only lesions of the heart that could be directly repaired and cardiac trauma could be dealt with any degree of success. Within this category was mitral regurgitation. Dwight McGoon, among others, pioneered techniques to reconstruct leaking mitral valves without the need for replacement. Mural leaflet imbrication and triangular resection of the mural leaflet were techniques pioneered by Dr. McGoon. This simple technique remains of use today. Surgery on the valves of the heart required a whole new branch of technological development, that of replacement heart valves. Several types were developed, but the most successful that has endured to this day was once again devised by the fertile mind of Dr. Walt Lillehei. The bi-leaflet valve is an ingenious idea which allowed excellent flow characteristics with washing of all of the leaflets in diastolic filling. At the same time, the biotechnology company Shiley was working with the Swedish surgeon Viking Björk on a single tilting disc variety, the Björk-Shiley valve. This too had excellent characteristics and was soon one of the preferred valves of choice. Many other variations were devised including the Starr-Edwards “ball-in-cage”, which was also very successful, if obstructive to outflow. This valve conceived by Albert Starr was in common usage well into the early twenty-first century. Poorly thought through changes to the Björk-Shiley valve resulted in significant early valve failure and withdrawal of the valve under very stressful circumstances for all, but mostly the patients. In parallel, the idea of tissue valves was being pursued. The ideas took the form of homografts, xenografts and hand-sewn bovine pericardium. Perhaps the most innovative idea was that of the National Heart and Guy’s Hospital surgeon, Donald Ross, who conceived of the idea of switching the pulmonary valve to the aortic position, positing that it would have the same size as the replaced aortic valve and was naturally designed for the purpose. It is a procedure that requires experience and considerable skill to perfect but is an excellent solution for younger patients. This Ross procedure has persisted to the present day. In the early days of tissue valve development, preservation of the tissue in a flexible and durable form was paramount. Alain Carpentier with the assistance of his wife developed the chemistry of valve preservation using glutaraldehyde to fix the cross-linkages on the surface of the tissue both removing the allergenicity of the surface protein and maintaining molecular integrity and strength. Working with Edwards, the Carpentier-Edwards valve became a mainstay of tissue valve replacement. The valves were taken from pigs (porcine) and sized with very careful quality control. For every valve accepted, many more were discarded. The valves are hand-sewn into the supporting stents, which are covered with Dacron cloth by workers with immense skill and dedication. The drawback with these valves is the orifice area, which is

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limited by the sub-aortic bar beneath the non-coronary cusp. In an attempt to override this problem, Marion Ionescu, surgeon at Leeds Infirmary, developed the use of pericardium. Again, working with his wife, he made the first pericardial valves. The orifice area was considerably greater than with a porcine valve. The initial valves began to fail early as the suture lines had been placed outside the stent posts and were tearing with the flexing of the valve. Once this problem had been resolved, the valve has gone on to be an established and excellent valve with excellent haemodynamics and durability. There have been many iterations of tissue valve technology, but these two valve types remain dominant. The advice of Dr. Kirklin, “choose a valve that has been around for a long time and use it for a long time”, rings very true (Personal communication). In the ensuing years, all aspects of valve and congenital surgery have developed apace, alongside the developments in cardio-pulmonary bypass, intensive care and refined diagnosis. Perhaps later than might be expected, surgery for coronary artery disease developed in the mid-1960s led by Dr. René Favaloro at the Cleveland Clinic. In 1910, Alexis Carrel, Nobel Prize winner in Physiology or Medicine in 1912, had demonstrated that a vascular graft from the descending aorta to the left main coronary artery was feasible and that it could be useful in the management of syphilitic (the usual cause at that time) ostial coronary artery stenosis. Despite this development in vascular surgery by Carrel in the early part of the twentieth century, it took half a century before coronary surgery became of age as an applicable operation. In 1958, W.P. Longmire anastomosed the internal mammary artery to a coronary artery that fell apart whilst attempting endarterectomy. Before this, in 1952, Vladimir Demikhov, the pioneering transplant surgeon, had done the same operation successfully in Moscow, but as a result of the communication blackout between the USSR and the USA, his work was not discovered until sometime later. The advancement of the procedure relied on the development of coronary visualisation. In 1958, Mason Stones inadvertently injected radio-opaque dye into the right coronary artery of a patient where the intent was to visualise the ascending aorta. Fearing the worst, Sones was mightily relieved when the patient’s heart, which had paused for a long moment, began to beat again. Inadvertently, this was the birth of coronary angiography. Once the coronary arteries could be visualised, surgery could be planned with accuracy paving the way for safe coronary artery bypass surgery, at one stage the most commonly performed operation in the modern world. Arterial revascularisation, using the internal mammary artery, began with the Vineberg procedure. Arthur Vineberg of McGill University began this work in 1946. The internal mammary artery was mobilised and ligated distally. The proximal end was buried in a tunnel in the muscle of the left ventricle. Unlike free bleeding into a skeletal muscle where a large haematoma would form, this did not happen in the myocardium which seemed to soak up the blood like a sponge. In 1950, he operated on the first human patient, who remarkably, 3 years later, reported feeling well and able to walk 10 miles through the bush without symptoms. He began a programme of treatment, which included wrapping the heart denuded of epicardium with mediastinal fat or greater omentum. Using the new Sones angiography, he later showed that 70–80% of patients produced identifiable anastomoses with the coronary circulation and with a mortality of only 2%. Direct anastomosis of the internal mammary artery to an obstructed coronary artery was described by Kolessov in 1967 and George Green in 1968. The success of this operation began the widespread dissemination of the practice of coronary artery bypass surgery or colloquially referred to as CABG.  René Favaloro then popularised saphenous vein grafting to extend the utility of the procedure in patients with multi-vessel disease. Corrective surgery of the aorta began with the introduction of the Dacron tube graft by Dr. Michael DeBakey. Several materials, mainly nylon based, were tried as tube grafts but none were successful. DeBakey discovered Dacron in a department store in Houston. It was sold as backing for turn-ups on trousers and other dressmaking techniques. His mother was a seamstress and taught him how to create a tube graft. He then produced his own tube graft and

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bifurcation grafts. A patient of DeBakey’s happened to be a sock manufacturer, and following a conversation with him about knitting they went on to develop the machine and plant to make knitted Dacron grafts. This same process is used today. Initially, these grafts had to be soaked in the fresh blood of the patient to form clots within the weave allowing the graft to be implanted without catastrophic haemorrhage. In these modern times, the grafts are pre-coated with collagen and albumin, and pre-clotting is no longer needed. A development that caused massive general interest in our speciality was the development of heart transplantation. Seen from the perspective of Theodor Billroth, who berated even the idea of surgery of any kind on the heart, this step was seen by many contemporary physicians, ethicists and theologians as a step too far. The mystic quality of the heart and the need for another human being to be deprived of their own heart in the state of brain death were viewed as repugnant and a modern form of cannibalism. The facts of the matter however were very different. Serious scientific work around, selection criteria, immunosuppression in the recipient and surgical management meant that by the early 1960s, laboratory work was showing significant promise. The outstanding problem however was that of satisfactory immunosuppression. Strides had been made in renal transplantation by Murray in Boston and Calne in Cambridge, but there is of course a profound difference between renal and cardiac transplantation. A failed renal transplant can be replaced with dialysis. There was no such meaningful long-term support for the ailing heart. Once again, a leader in the field by decades was Demikhov in Moscow, who had also transplanted the heart of a dog into another, which on the sixth day post-operatively managed to climb the stairs of the Kremlin, before expiring with rejection a few days later. He also transplanted the head of a puppy to another dog which functioned for several days. Norman Shumway in Stanford University had had been working tirelessly to develop the procedure and to try to understand the process of rejection. A major step forward was the simplification of the operation of implantation. He modified the procedure from attempting to anastomose all pulmonary veins, cavae and great vessels to the use of atrial cuffs and great vessels. With this, he made good progress in the laboratory. However, he realised that immunosuppression was not yet fit for purpose. Enter the charismatic South African surgeon Christiaan Barnard and his brother Marius. Barnard had spent time with Lillehei in Minneapolis and performed well leaving a good impression. On his return to Groote Schuur in Cape Town, his position was secured, and he returned for a period with Shumway picking up their technology. Without announcing his intentions, he returned to South Africa, precipitously gathered a team around him and performed the world’s first successful heart transplantation on Louis Washkansky, a diabetic with terminal heart failure. The news circled the globe, and Barnard became a surgical superstar overnight, featuring on the cover of Time magazine as well as almost every other respectable publication in every country. The inevitable happened, and suddenly every “self-respecting” cardiac surgeon “had a go” with catastrophic results. The first in the UK was by Donald Ross at the National Heart Hospital. Some early successes were reported, but most patients succumbed to rejection from days to weeks after surgery. The result of this was a moratorium on further attempts in the UK in the early 1970s. There was one small but most important shining light of persistence in California. Norman Shumway and his team continued to work steadily with improving results. During the decade of the 1970s, much was learnt to the extent that a relaunch of the procedure became viable in 1979. In January of that year, Sir Terence English and his team at Papworth Hospital in Cambridge began his programme, which despite the lack of adequate funding but with detailed and determined efforts began to yield good results. Others followed. Then another breakthrough came with the introduction of the new and game-changing immunosuppressant cyclosporin A. This was followed quite quickly by the transplantation of the heart-lung block for patients with cystic fibrosis and end-stage pulmonary hypertension by Shumway’s team once again.

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Contemporary results are excellent with 98% one year and 92% 5 years with a median survival of 10 years. This once outlawed procedure had become mainstream. As can be seen from this brief review, the early development of this important speciality frequently revolved around personal household experience and happenstance. As things have progressed, more science and engineered technology have been used to the point of sophistication that we know today. More recently, the mechanical artificial heart as a bridge to transplantation and a permanent replacement has made slow but steady progress. The percutaneous insertion of replacement heart valves moves ahead at a fast pace, and the treatment of coronary artery disease has become truly hybrid with evidence-based integration of transcatheter techniques of angioplasty and stenting with the judicious use of coronary bypass surgery. The story will not end here, and the next 70 years of development of cardiac disease treatment promises to be just as exciting as the first. References 1. Harken D. Foreign bodies in and in relation to the thoracic blood vessels and the heart. Surg Gynaecol Obstet. 1946; 83:117–25. 2. Arora R, Nair M, Kalra GS, Nigam M, Khalilullah. Immediate and long-term results of balloon and surgical closed mitral valvotomy: a randomised study. Am Heart J. 1993;125(4):1091–4. 3. Gott V.  Cross-circulation: a milestone in cardiac surgery. J Thorac Cardiovasc Surg. 2004;127(3):617.

Suggested Reading • Forrester J. The Heart healers. Misfits, Mavericks and rebels who created the greatest medical breakthrough of our lives. St Martin’s Press; 2015. ISBN 978-1-250-05839-3. • Morris T.  A history of the heart in eleven operations. Penguin Random House. ISBN 9781847923912. • Westaby S, Bosher C. Landmarks in cardiac surgery. Oxford UK: Isis Medical Ltd. ISBN 1 899066 54 3. 1997

Cambridge, UK

Francis C. Wells

Contents

Part I Ischaemic Heart Disease 1 Coronary Artery Bypass Grafting�����������������������������������������������������������������������������   3 Samer A. M. Nashef 2 Off  Pump Coronary Artery Bypass Grafting�����������������������������������������������������������   9 Rizwan Q. Attia and Ravi J. de Silva 3 Surgical  Treatment of Complications of Acute Myocardial Infarction: Postinfarction Ventricular Septal Defect and Free Wall Rupture �������������������������  13 Choo Ng 4 Complications  of Myocardial Infarction: Papillary Muscle Rupture �������������������  19 Francis C. Wells Part II Valve Surgery: Aortic Valve Surgery 5 Timing  of Heart Valve Surgery���������������������������������������������������������������������������������  23 Madalina Garbi 6 Surgery for Aortic Valve Replacement���������������������������������������������������������������������  25 Ismail Vokshi and Steven Tsui 7 Aortic Root Enlargement Techniques�����������������������������������������������������������������������  35 Rizwan Q. Attia, Shakil Farid, and Steven Tsui 8 Valve  Sparing Aortic Root Replacement������������������������������������������������������������������  43 Rizwan Q. Attia and Ravi J. de Silva 9 Minimally Invasive Aortic Valve Replacement���������������������������������������������������������  49 Rizwan Q. Attia and Shakil Farid Part III Valve Surgery: Mitral Valve Surgery 10 Surgical  Access to the Mitral Valve���������������������������������������������������������������������������  55 Francis C. Wells and Narain Moorjani 11 Surgical  Correction of Degenerative Mitral Valve Disease�������������������������������������  63 Francis C. Wells 12 Surgery  of Rheumatic Mitral Valve Disease�������������������������������������������������������������  89 Francis C. Wells 13 Mitral Valve Infective Endocarditis �������������������������������������������������������������������������  95 Narain Moorjani

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Part IV Valve Surgery: Tricuspid Valve Surgery 14 Tricuspid Valve Disease Techniques ������������������������������������������������������������������������� 105 Narain Moorjani, Francis C. Wells, and Samer A. M. Nashef 15 Tricuspid Valve Replacement������������������������������������������������������������������������������������� 113 Narain Moorjani Part V Surgery of the Aorta 16 A  ortic Arch and Ascending Aorta Replacement ����������������������������������������������������� 117 Ravi J. de Silva Part VI Surgery of the Failing Heart 17 Cardiopulmonary Transplantation: An Overview��������������������������������������������������� 125 Marius Berman 18 Lung Transplantation������������������������������������������������������������������������������������������������� 129 Pradeep Kaul, Lu Wang, and Mohamed Osman 19 Orthotopic Heart Transplantation ��������������������������������������������������������������������������� 139 Ahmed Al-Adhami and Steven Tsui 20 Heart-Lung Transplantation������������������������������������������������������������������������������������� 149 Muhammad U. Rafiq and Steven Tsui 21 Mechanical  Circulatory Support and DCDD Heart Transplantation������������������� 155 Stephen Large and John Onsy Louca Part VII Pulmonary Thromboendarterectomy 22 Pulmonary Endarterectomy Surgery����������������������������������������������������������������������� 165 David P. Jenkins Part VIII Pericardial Disease 23 Pericardiectomy  for Constrictive Pericarditis��������������������������������������������������������� 173 Jason Ali Index������������������������������������������������������������������������������������������������������������������������������������� 179

Contents

Contributors

Ahmed Al-Adhami, MBChB (Hons) MRCSEd  Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK Jason  Ali, MA (MedEd), PhDm, FRCS Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK Rizwan Q. Attia, MS, MD, PhD, FRCS(C-Th)  Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK Marius  Berman, MD, FRCS (CTh) Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK Shakil Farid, FCPS (Surgery), FRCS (C-Th), MBA  Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK Madalina  Garbi, MD, MA, FRCP  Department of Cardiology, Royal Papworth Hospital, Cambridge, UK David  P.  Jenkins, FRCS, MS (Lond), FRCS (CTh)  Department Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK Pradeep Kaul, FRCS (CTh)  Royal Papworth Hospital, Cambridge, UK Stephen Large, FRCS (CTH), MRCP, MBA, PAE (RCP)  Department of Cardiac Surgery, Royal Papworth Hospital, Cambridge, UK John Onsy Louca, FRCOG, MSc  Gonville & Caius College, Cambridge, UK Narain Moorjani, MB ChB, MRCS, MD, FRCS (CTh), MA  Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK Samer  A.  M.  Nashef, MB, ChB, FRCS, PhD Department of Surgery, Royal Papworth Hospital, Cambridge, UK Choo Ng, MB BCh FRCS (CTh)  Department of Cardiothoracic Surgery, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK Mohamed Osman, MD, PhD  Transplant Surgery, Royal Papworth Hospital, Cambridge, UK Muhammad  U.  Rafiq, FRCS C-Tha Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK Ravi  J.  de Silva, MBBS, MRCS (Ed), MS, FRCS (CTh)  Department of Surgery, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK Steven  Tsui, MD, FRCS (Eng), FRCS(C-Th)  Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK

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Ismail Vokshi  Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK Lu Wang  Transplant Surgery, Royal Papworth Hospital, Cambridge, UK Francis C. Wells  Department of Cardiothoracic Surgery, Papworth Hospital, Cambridge, UK Royal Papworth Hospital, Cambridge University Group of Hospitals, Cambridge, UK

Contributors

Part I Ischaemic Heart Disease

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Coronary Artery Bypass Grafting Samer A. M. Nashef

In 1964, Vasilii Kolesov carried out the first coronary artery bypass grafting (CABG) operation using the left internal mammary artery (LIMA) to graft the left anterior descending (LAD) in St Petersburg. Three years later, René Favaloro performed a similar operation at the Cleveland Clinic using a saphenous vein graft. Half a century after this pioneering work, CABG is now one of the most frequently performed surgical operations in the world. Despite increasing competition from percutaneous intervention, CABG remains a phenomenal success story, unparalleled in its remarkable dual ability to eliminate symptoms and extend life, both of which are achieved at a very low risk of mortality which should be less than 1% overall. The standard version of CABG, and the one that features in the overwhelming majority of operations, consists of grafting the LAD with the LIMA and using saphenous vein grafts for other coronary arteries, with the operation being performed on cardiopulmonary bypass, a cross-clamped aorta and cold blood cardioplegia. Myriad alternatives to this have been proposed, such as total arterial revascularisation, minimal access approaches, video-assisted and robotic surgery, hybrid revascularisation, and off-pump CABG, with a variety of claims to better short-term and long-term outcomes. These approaches are performed successfully in many centres, but have not yet supplanted the standard operation which will be the central theme of this chapter. I shall describe the steps taken to bypass the three major coronary arteries (the left anterior descending (LAD), the right or posterior descending coronary artery (PD), and the major obtuse marginal (OM) branch of the circumflex).

Procedure Preparation After sternotomy, the LIMA is taken down. Using a retractor that elevates the left hemisternum, the LIMA is harvested as a pedicle, with surrounding veins and soft tissue, taking care not to injure it or even touch it. This can usually be achieved using only diathermy and blunt dissection, but occasionally metal clips may need to be used for large side branches. It is important that the entire length of the artery is taken down, especially proximally, so that the graft lies posterior to the left lung for the most direct route to the LAD. The LIMA is then left attached to the circulation at both ends while preparations are made for cardiopulmonary bypass. During the LIMA harvest, the long saphenous vein is taken from the lower leg, starting at the ankle and going up to just above the knee to secure sufficient length for two grafts, or further if additional grafts are contemplated. Once heparin has been given and the bypass cannulae are in place, the LIMA is divided distally and checked for good flow before applying a bulldog clamp. The vein is checked for leaks, calibre and overall suitability as a conduit. Bypass is then instituted, and the next few minutes are spent in planning the operation by identifying and preparing the target coronary arteries, so that there are no surprises once the aorta is clamped. A 15 blade is used to divide any epicardial fat over each target. Inspection and palpation ensure that there is no atheroma or calcium at the planned anastomotic site. The aorta is then clamped, and cardioplegic solution is infused into the aortic root. With the heart stopped, the cardioplegic cannula is attached to a pump sucker, but this should be switched off before any coronary is opened, to prevent damage to the back wall of the artery on arteriotomy.

S. A. M. Nashef (*) Department of Surgery, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_1

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S. A. M. Nashef

Distal Anastomoses Usually, the right coronary or its PD branch is done first. Access is made easier by dropping any left-sided pericardial stay sutures and rotating the heart away from the surgeon with a couple of moist swabs tucked in behind the right pulmonary veins. The already prepared anastomotic site is entered with a sharp, pointed blade, or diamond knife. The aortic root suction can now begin. The arteriotomy is extended with fine Potts scissors or similar. An arteriotomy of around 5–7 mm is usually sufficient. The technique I shall describe for the distal anastomosis is my own, but has the distinction of having been invariably adopted by every trainee who has been through Papworth in the last 30 years, so that it is now in very widespread use. It is also time-efficient and, on a good day, with favourable access and no snags, a distal anastomosis can be completed in less than 7 min. Once the heart has been correctly positioned and the arteriotomy has been made, the surgeon holds the end of the vein with the adventitia pinched between thumb and forefinger. The scrub nurse passes the surgeon a 7/0 double-ended polypropylene suture mounted on a ratchetless Castro-type needle holder with a small rubber-shod mosquito forceps clamped on the other end of the suture and held by the nurse. (Note: ratcheted needle holders can also be used, but the ratchet slows the procedure down, jerks the needle while in the tissues and prevents the use of the SEXI techniques [1].) The first suture is through the vein, outside-to-in, 1 mm from the heel on the surgeon’s side. The surgeon then withdraws the suture and while pulling it through, the nurse brings the other end held by the mosquito to lie on the chest wall just lateral to the right sternal retractor blade (Fig. 1.1). A fold in the surgical drape helps prevent the mosquito falling to the side. The surgeon then takes the coronary 1 mm from the heel, inside-to-out, picks up the needle, and takes the heel of the vein outside-to-in (Fig. 1.2), then the heel of the artery, then the vein 1 mm beyond the heel, and similarly the artery. We now have three loops of suture joining the heels of vein and artery (Fig. 1.3). Pulling only on the active suture end, the vein is brought down until it touches the artery. Then pulling on the suture is stopped, and the vein is drawn away to take up any slack in the loops. This is repeated till the vein and the artery are together (this method prevents sutures from slicing through either the coronary or the conduit: one should never pull simultaneously on suture and conduit). At this point, the fold in the surgical drape is straightened out and the mosquito clip allowed to fall gently under gravity so as to keep the artery open with its opposing walls away from each other.

Fig. 1.1  The start of a distal anastomosis: the first pass takes the conduit one stitch from the heel, outside-to-in. As your hand is holding the conduit, be sure to pick up the needle ready for the next stitch in the coronary artery and avoid having to remount

Fig. 1.2  The second suture in a distal anastomosis: take the coronary artery one stitch from the heal, inside-to-out. Similarly, pick up the needle in situ ready for the next stitch in the conduit

Fig. 1.3  The three heel sutures are in, and the conduit should be ‘parachuted’ down onto the coronary artery in stages. Pull only on the active end of the suture, and never pull on conduit and suture simultaneously, to avoid the suture cutting through either vessel

1  Coronary Artery Bypass Grafting

The needle is now mounted backhand in the needle holder. The correct mounting stance should be chosen with the artery in mind, not the conduit. The assistant begins to follow by maintaining tension on the suture. The surgeon then grasps the vein by the adventitia near the ‘toe’ of the vein and positions it 2–3 mm above the ‘toe’ of the coronary artery, with a little traction towards the toe. The next suture is inserted into the vein outside-to-in. As soon as the needle is through the vein, the assistant relaxes tension on the suture, and the needle can be directly inserted into the artery at the same mounting stance (provided the correct stance was selected in the first place). It is picked up outside the artery, and the assistant resumes tension on the suture (Fig. 1.4). The same steps are repeated until the toe is reached and passed. Each of these sutures can be done with a single backhand staged pass through both conduit and artery provided the vein is positioned properly and the correct mounting stance is chosen for the needle in the needle holder. If the stance is wrong, there are techniques which allow stance exchange in situ (without withdrawing the needle and needle holder to remount). There should be five toe sutures, gradually changing angle from 90° to the coronary artery to zero and back to 90° on the opposite wall. For a right-handed surgeon, the switch from backhand to forehand should not take place until the apex of the toe has been passed, that is, after the fourth toe suture (Fig. 1.5).

Fig. 1.4  The ‘far side’ of the distal anastomosis is being completed. The assistant should follow by holding the suture tut when taking the conduit and relaxing when taking the artery. Mount the needle ready for the artery, not the conduit. As the latter is mobile, it can be picked up en passant, allowing each stitch to be completed in a single, two-stage pass

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Fig. 1.5  The toe of a distal anastomosis: note that there are five toe sutures, beginning at 90° to the artery on the far side and slowly rotating through the ‘down-the-barrel’ suture to 90° on the near side

The needle is then mounted forehand. The tension on the mosquito clip is released, and the clip positioned loose towards the cranial end of the drape, which serves to keep the artery open. The assistant holds the adventitia of the vein and pulls it gently away from the surgeon, opening the space between the vein and the artery. The anastomosis is then completed with single-staged forehand suture passes. The last suture is left loose, and cardioplegic solution is infused down the vein to de-air the anastomosis before the suture is tightened and then tied. Flow down the vein is checked by the perfusionist by setting perfusion pressure of the cardioplegia solution at 100  mmHg and reading the flow off the pump. The heart is then positioned for the OM graft. This requires rotating the heart anticlockwise on the atria, which should take the brunt of the twist instead of the ventricles. A heavy suture is placed in the posterior pericardium, pulled taut, and clipped between the teeth of the sternal retractor rack. This tents the posterior pericardium into an elongated peak on which the heart can be balanced. With the heart sufficiently rotated (far enough so that the right graft is now on the left-hand side of the ‘peak’), moist cold swabs are placed to the right of the right atrium to fix the heart on the right side. Additional swabs are placed below the obtuse margin of the heart superiorly. The left-sided pericardial stay is then elevated and clipped to the drapes. With these manoeuvres, the OM artery should be easily accessible with no further retraction. Occasionally, if the OM is relatively posterior, gentle finger pressure by the assistant through a swab placed just to the right of the OM can improve the exposure. The arteriotomy is made, and the anastomosis is then completed in exactly the same way as the right-sided graft. The LIMA anastomosis to the LAD is also done in exactly the same way except for two steps. The first is that the LIMA

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is positioned at the top end of the wound on the surgeon’s side with the pedicle secured with a clip the wound towel (holding it by hand is not as helpful as it is in the case of a venous conduit). The second is that the LIMA arteriotomy is oversized by at least 1 cm. This is to allow accurate trimming of the LIMA to size as the toe is approached, since the LIMA is far less forgiving of size discrepancies than the saphenous vein. The extra length of LIMA also provides a useful ‘­ handle’ of redundant LIMA which can be gripped with forceps with immunity as it will form no part of the anastomosis when trimmed off. The ideal time to trim the LIMA to size is one suture before the toe. With the anastomosis completed, the bulldog on the LIMA is removed and the suture tied after de-airing. Flow down the LAD is now established. Within less than a minute, the anterolateral surface of the left ventricle should contract when touched. If it does not, there may be a technical problem with flow down the anastomosis, which may need to be redone. Coronary arteries are small, and their walls may be transparent. They may have folds in the floor and, during the anastomosis, sections may place themselves in the line of the needle pass, especially at bifurcations or when an artery dips into the myocardium. Occasionally, the surgeon may inadvertently pick up the opposite wall or the floor of the artery while completing the anastomosis. This is especially the case if access is difficult or visibility is impaired by collateral flow of blood. There is, however, a useful sign that warns the surgeon that the needle has picked up something other than the intended edge: the ‘no wall motion’ sign. When a needle touches the wall of the coronary artery, we expect that wall to move slightly away under the pressure of the advancing needle before penetration happens. This very slight movement of the wall relative to the rest of the artery is a reassuring sign that nothing else has been picked up by the needle. If this wall motion relative to the rest of the artery is not clearly seen, there is a good chance that the back wall or some other part of the artery has been included in the suture. The solution is to withdraw that suture, reinsert it, and avoid a lot of potential grief later. Once all the distal anastomoses have been completed, the cross-clamp on the aorta is removed and the entire heart usually starts to contract in sinus rhythm provided the anastomoses were expeditiously performed and myocardial protection was adequate.

Proximal Anastomoses The most beautifully performed distal anastomoses are utterly useless if the proximal anastomoses are not done with care. In addition to a poorly performed suture, proximal anastomoses may compromise the operation in four ways: • Too long a conduit • Too short a conduit

S. A. M. Nashef

• A kink in the conduit • A twist in the conduit My system for preventing these problems relies on a number of technical steps. Other approaches exist, but this one is easy and reliable. To eliminate kinks, twists, and problems of length, each vein graft is cannulated with a Codman needle on a blood-­ filled syringe. Blood is injected down the graft looking at its entire length for twists or kinks (this may require lifting the heart to see the entire length of the graft). During this inspection, blood is injected into the vein to ensure the measurement of length is accurate for the graft as it will be while functioning and to confirm free unimpeded flow. Then the graft is placed in its anticipated final position and, while still injecting blood down it, the perfusionist fills the heart. When the heart is at normal size, the assistant grasps the entire vein with a deBakey forceps coming down vertically (not sideways or at an angle) and the surgeon cuts the graft in line with the jaws of the forceps. This defines the toe and heel of the proximal anastomosis with no risk of rotation. The toe of the vein is then gripped in a mosquito clamp and attached to a wound towel (if it reaches without tension) or the body of the mosquito clip is attached to the towel with a towel clip (if it doesn’t). The positioning of vein grafts is usually straightforward: diagonal and OM grafts leave the aorta towards the left, PD and LVB graft s towards the right, and a graft to the RCA straight down. An LVB graft and a graft to a terminal circumflex are better placed towards the right and passing behind the inferior vena cava. Once the measurement and positioning of all vein grafts are satisfactory, a partial occlusion clamp (or ‘sidebiter’) is applied to the anterior surface of the aorta. Most surgeons use a hole-punch to create the aortic incision for proximal anastomoses. I do not, and make simple straight incisions in the aorta anteriorly, angled in the anticipated direction of the graft to its target coronary vessel. If you do use a hole-punch, remember to incise on the side of the aorta so that the vein takes off towards the corresponding distal anastomosis. If you are happy with simple straight incisions, these can made on the most anterior part of the descending aorta and the graft will leave the aorta like a plane taking off from a runway (in a hole-punch anastomosis, the graft takes off from the aorta like a rocket rather than a plane, hence the need for lateral positioning of the punch holes to avoid the ‘rocket’ having to bend back towards the heart with the risk of kinking). The anastomosis is begun near the toe of the vein, outside-­ to-­in. That suture is then placed into the aortic incision as hard a forehand as you can manage, with your elbow right across the patient if it’s an OM graft, for example (Fig. 1.6). The next suture is then placed in the vein, and the corresponding suture on the aorta is the hardest backhand you can manage. With these two in place, everything becomes progres-

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airing. If not, the last anastomosis is left loose while the perfusionist is asked to reduce the flow. The sidebiter is removed, de-airing the aorta, and the suture is then quickly tied before resuming full flow. Finally, a very easy way to check that the proximal anastomoses are widely patent is to perform a ‘pop test’ on each vein graft: • The graft is occluded with forceps near its origin from the aorta • With thumb and forefinger, the graft is gently milked flat towards the distal anastomosis for a few centimetres and held closed • The forceps is then taken away Fig. 1.6  The proximal anastomosis starts at the toe of the conduit, outside-to-in, with the aortic suture as hard a forehand as you can manage. The next suture will be the hardest backhand and, thereafter, the suture stance becomes progressively easier until the heel

At that point, the flattened length of vein should immediately pop, visibly and palpably, within a fraction of a second, back to its blood-filled status. If it doesn’t, remains flat or fills slowly, the anastomosis is obstructive and must be refashioned.

 echnical Considerations for Special T Situations Sequential Grafting Sequential or ‘jump’ grafts can be very useful in many situations: shortage of conduit, a diseased aorta with limited space for proximal anastomoses, or simply to reduce the Fig. 1.7  The bayonet needle mount is particularly useful in the sutures time needed for proximal anastomoses in multi-grafting, around the heel, between the backhand and forehand stances, but the needle is unstable in the needle holder and will be dropped if it touches such as quadruple CABG and above. The downside is the anything before penetrating the target part of the aortic wall. Once the risk of ‘too many eggs in one basket’ scenario and the fact heel is completed and the first forehand pass is made, the conduit can be that, to ensure a successful sequential graft, the length and parachuted down into the aorta and the remaining sutures are easily the ‘lie’ of the conduit are critical to avoid kinking or undue done in single, two-stage passes tension on the anastomoses causing distortion of the graft or the target coronary. Some arteries are ideally situated for a sively easier. A few more backhand sutures are then placed, and sequential graft: the PD and the left ventricular branch of the the heel is reached. The heel is a sensitive point. It tends to be RCA, the second diagonal and the LAD, and any of two or that the needle stance switches from backhand to forehand at more OM branches. Others can also be grafted sequentially, the heel, and it is important to avoid excess travel on the aorta but require additional care and extremely careful planning to at that point, since that can flatten the vein into a ‘letterbox’ slit avoid the problems mentioned above. and compromise flow into it. This problem can be averted by For a good sequential graft, precise measurement of the the use of the ‘bayonet’ needle mounting stance, which allows length of conduit between the two coronary arteriotomies is suturing at a stance between backhand and forehand (Fig. 1.7). crucial. First, make both arteriotomies, but keep the side-to-­ The bayonet approach is easy, but the needle is highly side arteriotomy small (around 4 mm). Position the conduit unstable in the holder, and care should be taken not to touch over the heart with the distal end overlying the distal or end-­ the side of the aorta on insertion as that will almost certainly to-­side arteriotomy. This determines where the conduit incidrop the needle out of the jaws of the needle holder. The sion should be made for the side-to-side anastomosis. The instant the first forehand suture is through, the vein can be conduit is then lifted to expose its undersurface and filled parachuted down and the remainder of the anastomosis com- (with a saline syringe if it’s a vein or by moving the bulldog pleted very easily forehand. clamp distally if it’s a mammary artery). The incision is then When all proximal anastomoses are completed, the part made in the conduit. Sequential anastomoses are massively of the aorta within the sidebiter can be de-aired. If there is a easier to perform if the side-to-side one is done first. The vein graft with no valves, unclamping it will achieve the de-­ suture technique is otherwise identical to that employed in a

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non-sequential graft, but, if there is an angle in the path of the conduit over either anastomosis, the start of the suture on the conduit may have to be adjusted from the standard 1 mm from the heel to 2 or 3 mm in either direction. With the side-­to-­side anastomosis completed, injecting saline or blood cardioplegia down the graft should result in free flow from the distal end of the conduit and from the end-to-side arteriotomy if there is no complete occlusion between the two arteries: this is a useful quality check. Then the end-toside anastomosis is done using the same technique, with a similar adjustment if the conduit is approaching the coronary arteriotomy at an angle. In a well-performed sequential graft, the only visible clue to the existence of the side-toside anastomosis should be the cut end of the suture, with no discernible kinks, twists, or curves whatsoever in the conduit.

Conduit Shortage Sometimes there simply isn’t enough vein of good quality to complete all of the grafts. Options to deal with such a situation include more usage of sequential grafting or attaching a vein graft ‘piggy-backed’ to another if the former will simply not reach the ascending aorta without tension. For example, a diagonal graft can be very short and still reach the OM graft. An OM1, OM2, or distal circumflex graft that is too

S. A. M. Nashef

short will often easily reach the aorta if it is passed between the ascending aorta and the pulmonary artery.

The Diseased Ascending Aorta This is often a problem in proximal anastomoses in our increasingly aging and atherosclerotic patient population, but, provided there is sufficient healthy aorta for safe cannulation and cross-clamping, problems with the proximal anastomoses can be averted or side-stepped either by performing them on clamp to avoid the use of a sidebiter, or performing just one proximal anastomosis and attaching all other to that graft, or attaching one or more grafts elsewhere, such as the innominate artery. If none of these are options, replacing part of the ascending aorta may need to be done so that the proximal anastomoses are made to the neo-aorta. Woven Dacron aortic grafts are not easily amenable to partial occlusion clamps, so the proximal anastomoses may need to be done with the cross-clamp on.

Reference 1. Hosseinpour A-R, Hilton G, Nashef SAM.  Techniques of needle stance exchange in situ. Interact Cardiovasc Thorac Surg. 2005;4:289–91.

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Off Pump Coronary Artery Bypass Grafting Rizwan Q. Attia and Ravi J. de Silva

Off pump coronary revascularisation was performed first in St Petersburg in 1964 by Kolessov [1]. This technique was soon overtaken by development of cardiopulmonary bypass (CPB) and cardioplegia. The technique was revived again in the 1980s, driven by the financial benefits of not needing the bypass machine. Off pump has further developed with minimally invasive direct access coronary artery bypass (MIDCAB), typically consisting of anastomosing the left internal thoracic artery to the left anterior descending coronary artery through a small anterior left thoracotomy or lower midline sternotomy. Access to the lateral myocardium and right-sided vessels has been described [2]. The second approach is multivessel grafting without CPB undertaken through a median sternotomy allowing access to all coronary target vessels. This allows standard techniques of internal thoracic artery harvest. The introduction of stabilisation devices, exposure techniques, and improved haemodynamic management during the case has allowed increased graft patency and widespread use of this technique for all coronary territories to construct as many anastomoses required to treat the patient’s coronary artery disease [3–5].

Operating Room Setup and Preparation Patient normothermia is preserved by keeping the operating room warm, avoiding radiant heat loss and monitoring core body temperature with a nasopharyngeal temperature probe. A heating blanket is placed under the patient, and the patient is kept warm at 37 °C. We ensure that the heart-lung machine and perfusionist are available with a primed cardiopulmo-

R. Q. Attia (*) Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK R. J. de Silva Department of Surgery, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK e-mail: [email protected]

nary bypass machine. Confirm availability of stabiliser instruments, set of choice, a CO2 mister blower, and appropriately sized intracoronary shunts. Assure that the anaesthesiologist is comfortable with beating heart surgery as collaboration is critical for success.

Anaesthetics Involvement of the anaesthesia team is essential for successful off pump surgery. Maintenance of systolic pressure is important for the heart to tolerate hemodynamically unfavourable positioning. Alpha agents, inotropic agents, optimal fluid loading, and pacing are important to maintain cardiac output during manipulations.

Surgical Technique Standard median sternotomy is performed, and soft tissue and bone haemostasis is achieved. In my practice, a long pedicled left internal thoracic artery (ITA) is harvested using diathermy in combination with small and medium ligation clips. Length is important to ensure that there is no tension on the anastomosis whilst the heart is being manipulated. Simultaneous harvest of the long saphenous vein is undertaken using an endoscopic or open bridging technique. In patients with severe proximal stenoses >90% or chronic total occlusion who are young (below 65 years of age), the radial artery is an alternate conduit used for coronary artery grafting. In selected patients who are typically under 65 years old, not obese, non-smokers or those with extensive aortic calcification a second ITA is used as a conduit. Composite conduits (Y or T graft) with the left and right ITA and the radial artery are carried out in cases where aortic clamping is not possible to construct the proximal anastomoses. Anticoagulation is achieved with 300  U/kg of. ACT is measured every 30 min to ensure optimal range.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_2

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Sequence of Anastomoses This varies in accordance with the increasing order of cardiac displacement and manipulation required. As a guiding principle, a greater degree of cardiac displacement can be tolerated with increasingly complete revascularisation of the myocardium. This means usually the first graft is LITA to LAD, the inferior wall grafts (RCA or PDA) and then the lateral wall targets (OM). There is however variation depending on the patient anatomy and tolerability to displacement. I construct the distal anastomosis followed by proximal anastomosis first to allow immediate myocardial perfusion through the graft.

Set-up and Positioning The pericardium is opened in the midline with thymic tissue separated along the avascular midline plane. The pericardium is opened inferiorly as a T extending into the right pericardiophrenic angle whilst maintaining the right pleural integrity. This extension of the pericardial incision is particularly important as it allows translocation of the heart into the right pleural space when exposing the lateral wall coronary targets (the pericardial stay is relaxed), as well as making the inferior myocardial vessels more accessible (the pericardial stay is under tension). Pericardial stay sutures are placed three on each side with haemostats to create a pericardial well. The surgeon needs to be able to manipulate the heart markedly during the case with resulting influences on the haemodynamic response of the patient. Numerous techniques are used to achieve optimal heart positioning whilst ensuring good haemodynamics. Blood pressure is continually optimised during the procedure, and the mean arterial pressure maintained higher than 60 mmHg by repositioning the heart or patient, intravenous fluids, selective use of vasoconstrictors, or temporary epicardial pacing. The most important variable in off pump coronary artery surgery is a clear and open dialogue between the surgeon and the anaesthetist to continuously optimise the haemodynamics which facilitates exposure of the coronary arteries and the operation. Good exposure is obtained typically through a combination of heart rocking and using a stabiliser device. In addition, the pericardial stitches are used to enucleate the heart especially for lateral wall target grafting.

R. Q. Attia and R. J. de Silva

Construction of Anastomoses to the Anterior Wall The ITA is bought into the surgical field between the first and second pericardial well sutures that are clipped to chest wall through a slit in the left pericardium created to 2 cm distance from the left phrenic nerve. The artery is cut open with spring scissors and flow assessed and distal end prepared. The heart is lifted with the surgeon’s right hand, and one to two warm moist gauze swabs are placed under the heart (Fig. 2.1). This is typically sufficient to bring the LAD into view. In patients with large hearts which are displaced laterally, a deep pericardial retraction suture is required. A 1 Silk or Ethibond is used 3–4 cm below the left inferior pulmonary vein (Fig. 2.2). The suture must be placed rapidly and deliberately as lifting the heart causes haemodynamic compromise with impaired venous return as the inferior vena cava is kinked. The suture is pulled taut and secured to the drape on the left side of the patient. A small warm moist gauze swab is placed on the suture, and the heart is placed on this to bring it into midline. The identified site along the vessel is stabilised using one of the many stabilisers available on the market. The authors use Octopus® (Medtronic Inc.) placed on the lower boarder of the sternal retractor. The device works by using suction cups lifting the area of the myocardium between two arms and stabilising the coronary artery which is placed in the middle. The stabiliser has to be used as such and not a retractor which would lead to damage to the myocardium. The

Stabilizer on anterior heart

Conduit Harvest This is carried out as already laid out in the chapter on ‘on pump’ coronary artery bypass grafting.

Fig. 2.1  Positioning of the heart with the Octopus retractor so that the anterior wall is stabilised for grafting the LAD

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First DPRS—at the level of the LSPV

Second DPRS—twothirds of the distance toward the diaphragm Third DPRS—between IVC and LSPV Diaphragmatic pericardial edge sutured to the skin

Fig. 2.2  Positions for placement of deep pericardial sutures at various levels to allow lateral wall exposure

proximal vessel occlusion is carried out using a small ­bulldog clamp placed in the fat 1 cm away from the vessel. Alternate technique involves using silastic tape or 2/0 Prolene passed widely around the proximal vessel. Usually, no distal occlusion is required. The use of intracoronary shunts is recommended in cases where there is evidence of myocardial ischaemia on ECG or haemodynamic instability. The coronary artery is exposed using a 15 blade and opened with a bever blade. The anastomosis is performed in the usual manner using 8/0 Prolene suture. A CO2 mister blower is used to open the coronary artery and keep the operative field clean. The LITA pedicle is tacked down with a 6/0 Prolene suture closet to the surgeon’s side.

Construction of Anastomoses to the Lateral Wall A deep pericardial suture is used as described above this time placed on the posterior pericardial surface on a line drawn from the left inferior pulmonary vein to the inferior vena cava, placed halfway between the two. The patient is placed in steep Trendelenburg, and the table is raised and rotated towards the surgeon. This in conjunction with the extended ‘T’ pericardial incision as previously described, allows heart displacement to the right and apex to come anteriorly (Fig.  2.3). The suspensory pericardial well sutures on the right side are kept lose. In some cases with cardiomegaly, it might be necessary as an additional manoeuvre to open the right pleural space and dislocate the heart into the right chest

Fig. 2.3  Positioning for lateral wall target vessel revascularisation

cavity. Care must be taken during this step as the cardiac output can drop significantly if there is rotational torsion of the vena cavae. This brings the obtuse marginal and posterolateral branches of the right coronary artery into view. An Octopus® (Medtronic Inc.) stabiliser is used now fixed to the left boarder of the sternal retractor and onto the heart to stabilise the coronary artery. The technique for occlusion, opening, and anastomosis is as for anterior wall targets using 7/0 Prolene sutures.

Construction of Inferior Wall Anastomoses The right-sided pericardial stay sutures are pulled taut. The table is in steep Trendelenburg position, and the heart is lifted up with tension to the deep pericardial retraction suture to expose the target vessel into the middle of the operative field. The Octopus® (Medtronic Inc.) stabiliser is used to immobilise the artery (Fig.  2.4). Temporary occlusion is carried out with a bulldog clamp. Rarely, the ischaemia to the atrioventricular node can cause bradycardia. These cases might require placement of temporary atrial pacing wires to increase the heart rate. Right coronary artery exposure requires the table made to be moved to a flatter position, and retraction sutures are relaxed with the heart falling to the left side of the chest cavity. The technique for occlusion, opening and anastomosis is as for anterior wall targets using 7/0 Prolene sutures.

R. Q. Attia and R. J. de Silva

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routinely used by the author, however they are an important tool in minimising myocardial ischaemia and improving the safety of the operation.

Postoperative Management

Inferior wall

Fig. 2.4  Positioning for inferior wall target vessel revascularisation

Tips and Tricks • Anaesthesia support and active participation are essential to maintain excellent haemodynamics throughout the case and ensure there is no myocardial ischaemia during construction of the anastomoses with judicious blood pressure management to maintain coronary perfusion pressures and collateral vascular beds. • Surgeon must allow time for excellent presentation, stabilisation, and clean operative field prior to opening, after opening the vessel and construction of the anastomosis. If the exposure is compromised, then the quality of the anastomosis will be compromised with risk to patient safety. This would impact immediate and long-term outcomes for the patient. • The CO2 mister blower is an essential tool which must be used judiciously at below 5 L/min to allow visualisation but prevent damage to the endothelial lining of the vessels. • Intracoronary shunts (Guidant Flocoil intracoronary shunts from 1.5 to 2.5 mm in 0.25 mm increments) are not

Postoperative intensive care unit management was standardised for all patients. All patients received intravenous nitroglycerin (0.1–8 μg/kg/min) infusions for the first 24 h unless hypotensive (systolic blood pressure   60 mL/m2 BSA and development of atrial fibrilsymptoms, as well as detection of exertion-induced changes lation represent softer indications for mitral valve surthat predict decompensation. Furthermore, exercise echocargery, depending on the patient’s life expectancy and diography can be used in symptomatic patients with non-­ surgical risk. severe heart valve disease based on imaging at rest, to 2. Mitral regurgitation due to calcific mitral valve degenerareclassify the severity based on exercise-induced changes. tion with mitral annular calcification invading or retractSymptoms represent a strong (class I) indication for ing the mitral valve leaflets is a form of primary mitral mitral valve surgery in all guidelines. In the absence of regurgitation usually affecting older individuals with a symptoms, heart valve surgery is offered to patients with higher surgical risk, further increased by the typical severe heart valve disease and haemodynamic consequences mitral valve morphology. Consequently, taking into contypical for the type of valve disease. sideration risk and benefit, surgery is most likely offered in symptomatic patients. However, radiation-induced mitral valve calcification can affect younger individuals Mitral Regurgitation and, in this case, risk and benefit considerations differ. Timing of surgery for mitral regurgitation varies, depending on the primary or secondary nature of the regurgitation and specific considerations for each category. M. Garbi (*) Department of Cardiology, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected]

Secondary Mitral Regurgitation 1. Ventricular-secondary mitral regurgitation of ischaemic or non-ischaemic cause responds to heart failure medical treatment, revascularization, and/or cardiac resynchronisation therapy. Mitral valve surgery should be offered only if the regurgitation remains severe and the patient

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_5

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remains symptomatic or requires surgical revascularisation of coronary disease. 2. Atrial-secondary mitral regurgitation responds to offloading and rate or rhythm control of atrial fibrillation. Mitral valve surgery should be offered only if the regurgitation remains severe and the patient remains symptomatic.

threshold of 50% for a strong (class I) indication. Surgery should be also offered in case of increase in mean gradient during exercise by more than 20  mmHg, in case of rise in BNP and in case of very high transvalvular velocities (>5 m/s) and gradients.

Tricuspid Regurgitation Mitral Stenosis 1. Rheumatic mitral stenosis is treated mainly with transcatheter balloon commissurotomy and mitral valve surgery is offered only in case of unfavourable morphology. In the asymptomatic patient, depending on surgical risk, surgery can be offered in case of pulmonary hypertension with estimated systolic pulmonary pressure > 50 mmHg on echocardiography at rest, or in case of high thromboembolic risk (history of systemic embolization, dense spontaneous contrast in the left atrium, recent onset paroxysmal atrial fibrillation). 2. Calcific mitral stenosis implies similar considerations of risk and benefit with calcific mitral regurgitation. The first treatment should comprise rate control and diuresis, and care should be taken to avoid overestimation of mitral stenosis severity.

Timing of surgery for tricuspid regurgitation varies, depending on the primary or secondary nature of the regurgitation and coexistent pathology.

Primary Tricuspid Regurgitation Primary tricuspid regurgitation of degenerative aetiology can coexist with mitral valve prolapse. Primary tricuspid regurgitation due to a flail leaflet, usually of traumatic cause can manifest in isolation. Surgery should be offered to symptomatic patients without severe right ventricular systolic dysfunction, better assessed by cardiac magnetic resonance imaging. Surgery can be offered to asymptomatic patients with dilatation of the right ventricle and low surgical risk.

Secondary Tricuspid Regurgitation

Aortic Regurgitation In asymptomatic patients, aortic valve surgery is offered when the systolic function of the left ventricle drops, as assessed by an increase in the end-systolic diameter of the left ventricle or by a decrease in left ventricular ejection fraction. A drop in left ventricular ejection fraction to 29 mm. For this approach, the valve prosthesis would need to be held upside down without the valve holder handle before passing the valve sutures through the sewing cuff. The valve holder should be removed before parachuting the valve prosthesis into the aortic valve annulus. For the supra-annular technique, the first valve suture is a single-armed 2-0 braided polyester suture spanning across the membranous septum, entering and exiting on the aortic aspect of the right and non-coronary commissure (Fig. 6.4). The rest of the valve sutures are double-armed Teflon-felt pledgeted 2-0 braided polyester sutures passed from the ventricular to the aortic aspect of the aortic annulus. The sutures are placed in a horizontal mattress fashion in a clockwise sequence with each suture spanning a distance of 7–8  mm along the aortic annulus (Fig. 6.4). Traction on each newly placed suture elevates the aortic annulus to facilitate placement of the next suture, and so on. Leaving a 1 mm gap in between adjacent valve sutures helps to avoid spiking of the previous suture with the needle of the next suture. Usually, 11–15 horizontal mattress sutures are required for aortic valve replacement, depending on the size of the native aortic annulus (Fig. 6.4).

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Fig. 6.4  Top left, Location of the first valve suture across the right and non-coronary commissure entering and exiting 1  mm from the valve excision line and 7–8  mm apart. Retracting this suture towards the patient’s left hip helps exposure for placement of the next suture. Top

right, Horizontal mattress Teflon-felt pledgeted valve sutures being inserted in turn with each suture spanning 7–8 mm and leaving a 1 mm gap between adjacent sutures. Bottom middle, All sutures in place for the supra-annular technique

The sutures are placed with the needle entering the tissue perpendicularly to ensure a good depth of 2–3 mm is achieved before the point of the needle is swiveled towards the aortic

surface. Bearing in mind the anatomical structures around the aortic annulus, particular attention needs to be paid in the following locations:

6  Surgery for Aortic Valve Replacement

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Along the Non-coronary Annulus The AV node and the bundle of His are just behind and below the line of attachment of the non-coronary leaflet. It is advisable to insert the valve sutures immediately below the leaflet excision line and allow them to exit a fraction higher in the non-coronary sinus in order to avoid injuring the conduction apparatus.

Along the Aorto-mitral Curtain It is important not to plicate too much tissue with the valve sutures along the aorto-mitral curtain, particularly in the sub-­ commissural triangle between the left and non-coronary leaflet. Otherwise, this would compress the height of the anterior mitral valve leaflet and give rise to mitral valve incompetence.

Below the Left and Right Coronary Ostia At the nadir of the left and right coronary sinuses, the valve sutures should exit on the aortic side no more than 2  mm above the leaflet excision line in order to prevent the prosthetic valve sewing ring riding too high and causing obstruction to the coronary ostia. It is quite safe to start by inserting the needles lower in the ventricular aspect along these areas to ensure that there is a sufficient bite of tissue. For the intra-annular technique, all the horizontal mattress sutures are placed in an everting manner with the needles inserted on the aortic side first and exiting on the ventricular side of the excision line of the aortic valve leaflets, with the Teflon-felt pledgets resting on the aortic side (Fig.  6.5). Again, this is started at the right and non-coronary commissure going around the annulus in a clockwise direction. Once all the sutures are placed and counted, it is usually time to start the process of re-warming of the patient. The sutures are evenly spaced on the valve sewing ring starting with the suture from the right and non-coronary commissure and (Fig. 6.6) working clockwise until all the sutures have been passed (Fig. 6.6). For a stented bioprosthesis, the first commissural suture should be aligned with one of the valve posts. This will ensure that the three valve posts are not positioned in front of either of the coronary ostia. For bileaflet mechanical valves, the general consensus is to orientate the prosthesis so that the hinge line lies transversely with one leaflet facing anteriorly and the other leaflet facing posteriorly. All the valve sutures are then gathered under tension to take up any slack beneath the valve sewing ring before the prosthetic valve is parachuted down onto the native annulus.

Fig. 6.5  All everting sutures in place for the intra-annular technique

The suture directly beneath the left coronary ostium is tied first followed by the one directly beneath the right coronary ostium and then the nadir suture of the non-coronary sinus (Fig.  6.7). This ensures that the valve prosthesis is seated squarely in the supra-annular position and that the sewing ring would not tilt and obstruct either of the coronary ostia. All the remaining valve suture in between the three nadir sutures are then tied in turn. When tying each of the valve sutures, it is important that sufficient downward pressure is applied to the valve sewing ring with the finger on the knot to push the sewing cuff against the annulus before the suture is tightened. This means that the suture is simply tightened to hold the prosthesis in that position, rather than leaving the prosthesis high initially and then rely on tension on the suture to pull the sewing ring down towards the annulus. Usually, it is sufficient to use five throws for the knot and locking the last three throws. When all the sutures have been tied, the prosthetic valve leaflets are gently opened with a plastic probe to ensure that there are no redundant suture loops beneath the valve. The sewing ring should also be seen to be resting against the annulus with no space in between. Each of the tied sutures can then be cut flush with the knot (Fig.  6.7). Finally, clearance from the coronary ostia is confirmed. A 4-0 polypropylene running suture is used to close the aortotomy starting from each end of the incision and tied in the centre (Fig. 6.8).

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Fig. 6.6  Top, First valve suture placed through the prosthetic valve sewing ring. Bottom, Valve suture being placed through the prosthetic valve sewing ring in turn

Fig. 6.7  Top, Prosthetic valve parachuted down into the aortic annulus and the three nadir sutures have been tied. Bottom, All valve sutures have been tied and the sutures cut flush with the knots

6  Surgery for Aortic Valve Replacement

Fig. 6.8  Closure of the transverse aortotomy incision from both ends

De-airing, Trans-oesophageal Echocardiogram Assessment and Weaning of Cardiopulmonary Bypass For de-airing, the venous line of the bypass circuit is partially clamped to permit controlled filling of the heart. The lungs are re-inflated and ventilated. Suction on the pulmonary vein vent is temporarily suspended. The 8F cannula previously secured in the ascending aorta is connected to a cardiotomy sucker, and the heart is massaged to direct blood across the lungs and into the left heart. This is continued for a minute or so until most of the air in the left heart chambers has been expelled. Cardiopulmonary bypass flow is momentarily reduced to lower the aortic pressure for release of the aortic cross-­ clamp. Thereafter, bypass flow is restored. Cardiotomy suction on the pulmonary vein vent is resumed to prevent left heart distension and to continue the de-airing

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process. Ventricular and atrial epicardial pacing wires are secured and connected to a temporary pacing box. After a few minutes of reperfusion, cardiac activity usually returns spontaneously. If required, the heart can be defibrillated with DC cardioversion starting with 10 Joules. At this stage, it is not uncommon to see bradycardia or heart block. If so, sequential pacing at 80–90 beats per minute is commenced with more filling of the heart to facilitate de-­airing. When the left atrium is sufficiently full, the pulmonary vein vent can be removed and the puncture site on the vein left opened for further passive de-airing of the left atrium. Transesophageal echocardiography is invaluable in assessing cardiac filling status, contractility, the presence of regional wall motion abnormality and any occult pockets of air. It is also used to inspect the newly inserted aortic valve prosthetic for leaflet opening and paraprosthetic leak. If the findings are satisfactory and the heart is fully de-aired, the patient can be weaned off cardiopulmonary bypass. However, no matter how thorough the de-airing process has been up to this point, showers of air particles would invariably appear when the patient is finally weaned off cardiopulmonary bypass. Therefore, the authors would routinely continue with cardiotomy suction on the 8F cannula in the ascending aorta at a rate of 1 L/min as well as leaving the vent site on the pulmonary vein open for 2–3 min after weaning off bypass. During this time, the patient is re-transfused from the bypass machine at the same rate to maintain a steady filling pressure. When no more air bubbles are observed on echocardiogram, the suture on the pulmonary vein vent site can be tied and the cardiotomy suction on the 8F cannula is discontinued. The heart is decannulated and residual heparin is reversed with an appropriate dose of protamine sulphate. After haemosasis, anterior and posterior pericardial drains are inserted and the sternotomy incision is closed in a standard fashion.

References 1. Otto CM, Nishimura RA, Bonow RO, Carabello BA, Erwin JP, et al. 2020 ACC/AHA guideline for the management of patients with valvular heart disease. J Am Coll Cardiol. 2021;77(4):e25–197. 2. Vahanian A, Beyersdorf F, Praz F, Milojevic M, Baldus S, Bauersachs J, et  al. 2021 ESC/EACTS guidelines for the management of valvular heart disease: developed by the task force for the management of valvular heart disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Rev Esp Cardiol Engl Ed. 2022;75(6):524.

7

Aortic Root Enlargement Techniques Rizwan Q. Attia, Shakil Farid, and Steven Tsui

Aortic valve replacement can be challenging in the setting of a small aortic annulus. If the native aortic annulus can only accommodate a smaller-sized valve prosthesis, it would result in a restricted effective orifice area. When indexed to the body surface area, this could result in patient prosthesis mismatch in larger patients. This has been associated with adverse outcomes such as increased left ventricular work, inferior left ventricular mass regression and in some series, increased early and late mortality. In active younger patients, a high transvalvular gradient can lead to reduced exercise capacity. The body surface area of patients can be calculated pre-­ operatively from their weight and height. According to published valve sizing charts and apps, the minimum size of valve prosthesis required to avoid patient prosthesis mismatch can be prospectively determined. An intraoperative transoesophageal echocardiogram can provide annular dimensions for confirmation. Several techniques of aortic root enlargement have been described to allow the insertion of a larger prosthetic valve into a small aortic annulus. These techniques are described in the following chapter. The surgical set-up, access, and exposure are as described in the chapter on aortic valve replacement. In addition, a balloon-tipped coronary sinus cannula can be inserted for the administration of retrograde cardioplegia. After the aorta is cross-clamped and the heart is arrested, a transverse or an oblique aortotomy is performed at the level of the sinotubular junction. The diseased aortic valve leaflets are resected, the valve annulus is thoroughly debrided and sized using standard valve sizers. The techniques described in this chapter will include the Nicks procedure [1], the Manouguian-Nunez procedure [2, 3], the Konno-Rastan procedure [4], and the Y technique [5].

R. Q. Attia · S. Farid · S. Tsui (*) Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected]; [email protected]

 eometric Consideration for Aortic Root G Enlargement In geometry, the circumference of a circle is equal to its diameter multiplied by the mathematical constant π  (i.e. 3.14159….). Since manufacturers of aortic valve prostheses usually supply each valve model with 2  mm increments in diameter (19 mm, 21 mm, 23 mm, 25 mm, etc.), the difference in circumference between any one valve prosthesis and the one next size up would be 2 mm multiplied by π which equals to 6.28318  mm; the difference in circumference between a valve prosthesis and the one that is two sizes up would be two times 2 mm multiplied by π which equates to 12.56636 mm. For valves that are three sizes different, the difference in their circumference would be three times 2  mm multiplied by π which equates to 18.84954 mm. So, 6.3 mm, 12.6 mm, and 18.9 mm are the increases in circumference required to accommodate a prosthetic valve that is one, two, or three sizes larger than the native aortic annulus, respectively. In commonly with all techniques described for aortic root enlargement, the native aortic annulus is incised, and a patch of prosthetic material is sutured into the gap created. Since the suture line between the patch and the native tissues must incorporate 2.5–3 mm of patch material, and there is a suture line on each side of the patch, an additional 5–6 mm must be added to the increase in circumference desired to determine the appropriate width of patch material required. Depending on the magnitude of aortic annular enlargement desired, the following approximate width of patch material should be considered: Increase by 1 valve size  =  6.3  mm  +  6  mm  =  12.3  mm, rounded up to 13 mm Increase by 2 valve size  =  12.6  mm  +  6  mm  =  18.6  mm, rounded up to 19 mm Increase by 3 valve size  =  18.9  mm  +  6  mm  =  24.9  mm, rounded up to 25 mm These approximate patch widths are irrespective of what the native aortic annular diameter is before enlargement.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_7

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Nicks Technique For this a vertical incision is made in the aortic root across the aortic annulus in the mid portion of the non-coronary sinus and into the fibrous subaortic curtain (Fig. 7.1a and b). Ideally, the apex of this incision reaches 1.5–2 cm below the aortic valve annulus but this can be limited by the depth available in the anterior mitral leaflet. A patch of bovine pericardium is shaped elliptically. The key to success is to ensure that the patch at the level of the aortic annulus is of sufficient width (see above). A 5-0 polypropylene running suture is used to anastomose the patch to the margins of the incised aortic root starting at the apex of the incision and extending up each side of the incision (Fig.  7.2a). Each suture line is continued about 2  cm cranial to the native annulus (Fig. 7.2b). A valve sizer of the anticipated size of prosthesis is used to confirm the fit and the valve position. Some surgeons would find it helpful to use a sterile surgical marker pen to outline the edge of the valve sizer on the pericardial patch to aid positioning of the valve sutures. It is also important to locate the coronary ostia to ensure that they are

a

R. Q. Attia et al.

well clear of the edge of the valve sizer and the valve posts in case of a stented bioprosthesis. Similar to a standard aortic valve replacement in a native annulus, we would advocate supra-annular placement of the prosthetic valve with a non-everting horizontal mattress technique using 2-0 pledgeted or non-pledgeted Ethibond sutures (non-absorbable braided nylon sutures) around the annulus. The valve sutures along the pericardial patch are horizontal mattress sutures placed from the outside of the patch into the aorta (Fig. 7.2c). The sutures are then passed through the sewing cuff of the prosthesis, and the valve is seated on the annulus and tied. After the valve is tied down, close inspection is carried out to confirm that the valve is well seated. The coronary ostia are visualised to confirm no obstruction. The pericardial patch used to enlarge the aortic root is now trimmed into shape to match the aortic closure. A 4-0 running polypropylene suture is used for aortotomy closure. The aortic closure suture is tied to the 5-0 polypropylene sutures used earlier for the patch to complete the closure of the aorta. The final result of the closure is seen in the schematic diagram (Fig. 7.2d).

b

KonnoRastan

ManouguianNunez

Nicks

Fig. 7.1 (a) Aortic root accessed after aortic cross-clamping and transverse aortotomy. Strategically placed stay sutures as shown can facilitate exposure. (b) The locations of incisions for the most commonly performed aortic root enlargement are shown by the dash lines

7  Aortic Root Enlargement Techniques

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a

b

c

d

Fig. 7.2 (a) The Nicks procedure with the aortic root incised through the centre of the non-coronary sinus across the fibrous aortic annulus and extending onto the anterior mitral leaflet. A bovine pericardial patch is sutured using a 5-0 polypropylene suture starting from the apex of the incision of the mitral valve leaflet. (b) The suture is used to run on both sides of the patch towards the aortic annulus and up the aortic root towards the aortotomy incision to complete the aortic root reconstruction. (c) Interrupted horizontal mattress pledgeted valve sutures are passed

from outside of the patch into the aortic aspect. The valve sutures for the native aortic annulus are interrupted horizontal mattress sutures passed from the ventricular to the aortic side for supra-annular valve placement. The sutures are then passed through the cuff of the sewing ring. The valve is tied down in the usual fashion. (d) A 4-0 polypropylene running suture is used to close the aortotomy starting at each end of the aortotomy incision. An incision in the cranial edge of the aortotomy incision may be required to accommodate the upper end of the pericardial patch

Manouguian-Nunez Technique

mitral continuity and onto the anterior mitral leaflet (Fig. 7.3a). By extending this incision to within 5 mm of the free margin of the anterior mitral valve leaflet and incising into the roof of the left atrium, the aortic annulus can be enlarged by at least two prosthetic valve size. Care is required to preserve the choral apparatus of the anterior mitral valve leaflet.

This procedure is a variation on the Nicks procedure for posterior aortic root enlargement. Here, a vertical incision in the aortic root is made across the aortic annulus at the commissure between the left- and the non-coronary sinus across the aortic-

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a

b

c

d

Fig. 7.3 (a) The Manougian technique with Nunez modification. The incision shows the Nunez technique and the classical Manougian extension to the anterior mitral valve leaflet. We have also added an incision in the roof of the left atrium to allow the widest possible aortic root enlargement with this approach. (b) A pre-shaped double thickness of bovine pericardial patch is sutured on either side with a 5-0 polypropylene suture as shown. (c) The two 5-0 polypropylene sutures on either side of the double pericardial patch is passed through the edge of the aortic root incision at the level of the aortic annulus. The posterior leaf of the double patch is hinge towards the right of the patient and used to repair the defect in the left atrial roof using a continuous 5-0 polypro-

pylene suture; the anterior leaf of the double patch is hinged towards the left of the patients and used to repair the defect in the anterior mitral leaflet using another 5-0 polypropylene suture. The supra-annular valve implantation is performed using interrupted 2-0 pledgeted Ethibond sutures in the standard fashion. The sutures are placed from outside the patch into the aortic aspect and passed through the sewing cuff of the prosthesis. (d) The valve is tied in place and the double patch can be seen “bifurcating” at the level of the aortic annulus with one leaf patching the left atrial roof and the other leaf patching the anterior mitral leaflet

The resultant defects from these incisions are closed using a double thickness patch of bovine pericardium that bifurcates at the level of the aortic annulus (Fig. 7.3b). A 5-0 poly-

propylene stay suture is used to approximate each side of the hinge point of the double thickness patch to each cut edge of the aortic annulus. The inner leaf of the patch is hinged

7  Aortic Root Enlargement Techniques

towards the left ventricular outflow tract to repair the defect in the anterior mitral valve leaflet using a fresh 5-0 polypropylene suture starting at the apex of the mitral leaflet incision and running towards the aortic annulus on each side of the patch (Fig. 7.3c). The outer leaf of the double patch is hinged onto the roof of the left atrium. A separate 5-0 polypropylene suture is used starting at the apex of the left atrial incision and running towards the aortic annulus on each side of the patch and tied against the corresponding suture from the mitral leaflet repair (Fig. 7.3d). Finally, the two 5-0 polypropylene stay sutures at either side of the hinge point of the patch is run up each side of the double patch and the aortic root. The enlarged aortic root is sized, an aortic valve prosthesis is inserted, and the aortotomy is closed as ­ described in the previous section. It cannot be emphasised enough that all the suture lines must be haemostatic, especially those between the mitral leaflet and the pericardial patch. An additional 5–7 min doing this can avoid having to redo the whole procedure!

Konno-Rastan Technique This is an anterior aortic root enlargement or an aortoventriculoplasty that is most commonly performed in congenital cardiac surgical units and is rarely deployed in the adult pop-

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ulation. It is included briefly in this chapter for the sake of completeness. The aortic root is mobilised by separating the right coronary sinus and the pulmonary trunk down to the level of the aortic annulus. A vertical aortotomy is performed to the left of the right coronary ostium from the level of the sinotubular junction and into the right coronary sinus (Fig.  7.4a). The incision is then extended onto the anterior surface of the right ventricular outflow track and into the interventricular septum as far as required for the desired aortic root enlargement (Fig.  7.4a). The danger is that the deeper the incision the higher the risk of injury to the first septal branch of the left anterior descending artery. Next a large bifurcating double layer of diamondshaped bovine pericardial patch is used to reconstruct the left ventricular outflow tract using 4-0 polypropylene running suture (Fig. 7.4b) starting at the apex of the incision in the interventricular septum. When these sutures reach a level of 5  mm above the native aortic valve annulus, the enlarged aortic annulus is sized, the valve sutures are inserted, and the aortic valve prosthesis is implanted (Fig. 7.4c). The inner leaf of the double layer of pericardial patch is used to repair the defect in the aortic root. The outer leaf of the double layer of pericardial patch is used to repair the defect in the right ventricular outflow track (Fig. 7.4d).

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a

Pulmonary outflow tract

Aortotomy

Cardiomyotomy through right coronary cusp

SVC

Pulmonary valve Right ventricular cardiomyotomy Right coronary a.

Aorta

Pulmonary trunk RVOT Ventricular septum

Fig. 7.4 (a) Konno-Rastan aortoventriculoplasty. The aortic root is enlarged with an incision through the right coronary portion of the aortic annulus, near the commissure, between the right and left coronary cusps. The incision is deepened into the interventricular septum, and a matching incision is made on the right ventricular free wall to enlarge the right ventricular outflow tract. (b) A diamond-shaped double patch of bovine pericardium is placed deep into the interventricular septal incision. Continuous sutures are used to attach the double patch to the ventricular muscle running up to the level of the aortic annulus. (c)

Pledgeted 2-0 Ethibond sutures are used to secure the prosthetic valve to the aortic annulus and through the double pericardial patch from the RV to the LV side. The sutures are then passed through the sewing ring of the prosthetic valve. (d) The outer leaf of the double pericardial patch is folded outwards to repair the right ventricular free wall defect, and continuous sutures are used to attach the patch to the muscle. The inner leaf of the double pericardial patch is used to close the left ventricular outflow tract using the continuous suture technique

7  Aortic Root Enlargement Techniques

b

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Outside patch with pledgeted annular sutures placed through inside patch

c

Aortic valve replaced

d Top area of inner patch to be used for closing aortic defect

Right ventricular defect closed with RVOT outer patch

Aorta

Right coronary artery

Fig. 7.4 (continued)

Pulmonary trunk Aortic part of inside patch Outside patch over RVOT defect

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Y Technique There is a recent addition to the literature of a Y incision at the aortomitral curtain and a rectangular patch enlargement of the aortic root described by Yang, apparently allowing three to four size increase in the aortic prosthesis without violating the mitral valve [5]. However, since there is currently limited long-term follow-up on this techniques, readers are referred to the original publication for further information.

Conclusions A physically active patient with a disproportionately small aortic annulus is at risk of patient prosthesis mismatch following standard aortic valve replacement which is associated with inferior early and late outcomes in some studies. The various procedures described for aortic root enlargement are effective in the hands of an experienced surgeon [6].

R. Q. Attia et al.

However, good myocardial protection and meticulous care must be taken during surgery to ensure safe and reproducible results.

References 1. Nicks R, Cartmill T, Bernstein L. Hypoplasia of the aortic root. The problem of aortic valve replacement. Thorax. 1970;25:339–46. 2. Manouguian S, Seybold-Epting W.  Patch enlargement of the aortic valve ring by extending the aortic incision into the anterior mitral leaflet: new operative technique. J Thorac Cardiovasc Surg. 1979;78:402–12. 3. Nuñez L, Gil Aguado M, Pinto AG, Larrea JL. Enlargement of the aortic annulus by resecting the commissure between the left and noncoronary cusps. Tex Heart Inst J. 1983;10:301–3. 4. Konno S, et  al. A new method for prosthetic vale replacement in congenital aortic stenosis associated with hypoplasia of the aortic valve ring. J Thorac Cardiovasc Surg. 1975;70:909–9917. 5. Yang B. A novel simple technique to enlarge the aortic annulus by two valve sizes. J Thorac Cardiovasc Surg. 2021;5:13–6. 6. Dhareshwar J, Sundt T III, Dearani J, Schaff H, Cook D, Orszulak T. Aortic root enlargement: what are the operative risks? J Thorac Cardiovasc Surg. 2007;134:916–24.

8

Valve Sparing Aortic Root Replacement Rizwan Q. Attia and Ravi J. de Silva

Valve preservation during aortic root surgery has evolved over the last two decades with efforts from surgeons such as Sir Magdi Yacoub and Tirone David. Aortic root replacement entails complete excision and replacement of the aortic valve, all aortic sinuses, and reimplantation of the coronaries into the prosthetic aortic root. This is the Bentall operation, first described in 1968. If the valve is preserved, then it is referred to as Valve Sparing Aortic Root Replacement (VSARR). The procedure has been simplified and standardised by surgeons such as Duke Cameron with exceptionally robust outcomes [1–3]. This technique is categorised into aortic root remodelling (aortic graft sits on top of the valve complex) or reimplantation (valve complex is located within the aortic graft). The remodelling operation creates neo-sinuses which have a theoretical advantage to leaflet integrity and flow

dynamics. This procedure does not stabilise the aortic annulus (Fig. 8.1). Modifications to the remodelling operation buttress the annulus using sutures or prosthetic strips which have yielded non-uniform outcomes. Custom prostheses allow combined remodelling of sinuses and annular stability of reimplantation. One such prosthesis is the Valsalva graft which is a bovine gelatine impregnated Dacron graft which can be used in remodelling or reimplantation (Fig.  8.2). It combines a collar with horizontal pleats, a vertically pleated skirt section that makes the sinus segment, and horizontally pleated tubular segment which can be used to replace more of the ascending aorta as required. The graft comes in 24–34 mm sizes allowing use in most adolescent and adult aortic root reconstructions, our practice at Royal Papworth is to use this graft for the implantation technique of VSARR.

R. Q. Attia Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK R. J. de Silva (*) Department of Surgery, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_8

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a

R. Q. Attia and R. J. de Silva

b

Fig. 8.1  Aortic root remodelling procedure (Yacoub technique) for a valve sparing aortic root reconstruction. (a) The native diseased root is excised, and the native commissural posts with leaflets attached are retained. (b) Unlike the reimplantation technique, this technique reconstructs the aorta with a graft using three ‘tongue-like’ projections which

c

d

replace the native aortic sinuses. The graft is then sutured into the patients’ remnant aortic sinuses next to the annulus. (c) The coronary artery button as reattached and (d) the final result retains the native valve but does not stabilise the annulus as the aortic graft remains outside the native annulus

Surgical Technique

Fig. 8.2  Gelweave™ Valsalva graft (Terumo Aortic)

Median sternotomy is carried out, and after creation of a pericardial well, the heart is prepared for cannulation and placement onto cardiopulmonary bypass. Aortic arch cannulation is preferred with an appropriately sized aortic and dual stage venous cannula into the right atrium. Cardiopulmonary bypass is commenced, and the patient is cooled to 32 °C. One litre of cold blood cardioplegia is delivered into the aortic root using a DLP cannula into the ascending aorta after placement of an aortic cross-clamp. In cases of severe aortic valve incompetence, induction and maintenance doses of cardioplegia are delivered through a combination of direct coronary ostial and retrograde cardioplegia. Repeated intermittent dosing of the cardioplegia is performed every 20 min throughout the case. Topical cold saline is also used for myocardial protection, and a vent is placed in the left ventricle via the right superior pulmonary vein. The aorta is transected above the sinotubular junction (STJ), and if the ascending aorta is aneurysmal, this is excised, thus improving exposure to the root. The coronary buttons are fashioned and retracted away from the root using a pledgeted 4/0 prolene stay suture (Fig. 8.3). Stay sutures with 5/0 prolenes are placed on top of each of the three commissures, and the aortic sinus tissue is resected leaving a 5  mm wide circumferential rim which is used to construct the internal suture line. Aortic root dissection is carried out using a combination of electrocautery and sharp dissection to separate the right and main pulmonary arteries from the

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We use one of two techniques to choose the appropriate size for the Valsalva graft. One technique employs a St Judes Medical Valve Sizer with traction on the commissural stay sutures to assess the size of the STJ diameter. The STJ diameter is usually preserved or slightly reduced to maintain aortic leaflet apposition and valve competence. Once the ideal diameter is picked, 2–3  mm is added to account for aortic wall thickness as the Valsalva graft sits outside the aortic valve root complex. This means most adult females would receive a 30-mm and adult men a 32-mm graft. The other technique of graft sizing measures the interleaflet triangle height, which is most easily accessed at the left/non commissure. We find these two techniques corroborate accurately. The base of the graft is cut to three rings and the distal end to about five to seven rings. A long tubular graft makes suture placement difficult and typically this length suffices to replacement of most ascending aortae. Three black marks are already placed onto the graft which align with the comFig. 8.3  Dissection of the aortic root and fashioning coronary buttons missures. The authors use a surgical marker to make three further longitudinal markers that subdivide the graft into the three sinus segments. This marks sites of the coronary artery implants, the middle and nadir of each subannular suture. A Dissection around exterior aortic annulus small nick is made into the graft at the bottom along the already placed black lines to allow the graft to sink down into the left-right and right-non-coronary commissures. This allow easy low seating of the graft which is very important specially in cases where deep dissection of the root is difficult without entering the right ventricle. Usually, the nick needs a single interrupted 4/0 prolene suture to repair any gaps once tied down. Three horizontal mattress sutures are placed within the left ventricular outflow tract below the nadir of each leaflet and out through the aortic root using 3/0 prolene with rectangular pledgets (Fig. 8.5). The three sutures from the commissures are drawn up through the graft, and the subannular sutures are placed through the base of the graft where the previously placed surgical marks were made, denoting the midpoint of each sinus. The graft is now lowered into posiFig. 8.4  Deep circumferential dissection of the aortic root from the tion, and the subannular sutures are tied (Fig. 8.6). pulmonary artery, left atrium around the LVOT The aortic root complex is orientated within the graft (Fig.  8.7). In a symmetrical trileaflet aortic valve, the aortic root (Fig.  8.4). Next attention is turned to the non-­ ­commissures should correspond to the black lines on the coronary sinus, and the atrial and epicardial fat is dissected graft. Asymmetrical and bicuspid valves need further expert away from the annulus and the left-right coronary aortic leaf- judgement which can only be gained with experience and is lets are separated from the pulmonary artery as low as pos- beyond the remit of this chapter. The haemostatic suture line sible. A circumferential deep dissection of tissue is required is now constructed from the pledgeted 5/0 prolene horizontal below the annulus of the aortic valve (Fig. 8.4). This may be mattress suture placed at the tip of each commissure. If the particularly hazardous below the right coronary cusp, and correct graft size is chosen, this suture will sit just below inadvertent breach of the right ventricle can be difficult to where the skirt of the graft transitions to the tubular section. repair. We prefer sharp dissection in this area in combination Both limbs of the suture are taken through the graft and tied with a surgical peanut to peal the right ventricle away from together on the outside keeping both needles attached. One the aortic annulus. needle is hung on a rubbershod whilst the other needle is Left coronary button

Right coronary button

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Fig. 8.5  Three horizontal mattress 2/0 Ethibond sutures placed from within the LVOT and out through the aortic root below the nadir of aortic valve leaflet

Fig. 8.6  The valve commissural sutures are placed through the graft which is lowered in place with the anchoring sutures placed within the aortic root

R. Q. Attia and R. J. de Silva

Fig. 8.7  The three anchoring subannular sutures are tied, and the aortic valve complex is orientated. Next step is assessment of the commissural sutures which are tied and the haemostatic suture line is begun within the graft valve complex

passed through the graft and the 5 mm circumferential aortic tissue. The internal suture line is then constructed with this 5/0 prolene suture either as a running ‘in and out’ suture line (Fig. 8.7) or as an ‘over and over’ technique. It is crucial to incorporate both graft and aortic tissue with every bite, and to instruct your assistant to maintain tension on the suture line throughout. As you approach the next commissure, it helps to secure this commissure to the graft as previously described, and then tie the suture used to construct the long internal suture line to one limb of the commissural suture on the outside of the graft. Thus, eventually the internal suture line is completed (Fig.  8.7). Two points to note are to straighten the graft and the tissues to avoid any folds and take care not to injure the leaflets. Once all suture lines are completed, we inspect the graft and perform static testing with saline to assess leaflet apposition and test valve competence. This is done with the left ventricular vent on to create negative suction on the aortic valve, so any incompetence is exaggerated. By passing the wall sucker through the aortic valve and then slowly withdrawing, it also gives a useful indication of leaflet coaptation length, which should ideally be more than 5 mm. Valve repair can now be carried out if required. Any prolapsing areas can be treated with a 5/0 prolene suture to fold the midportion of the free leaflet. Any small fenestrations are also similarly repairable, although if these are covered by the coapting leaflets, it is preferable to leave well alone. Next attention is turned to attaching the coronary buttons starting with the left which is usually in alignment with the midportion of the left coronary sinus (Fig. 8.8). A burner is

8  Valve Sparing Aortic Root Replacement

Fig. 8.8  Once the internal suture line is completed, the coronary ostia are positioned and attached to the Valsalva graft using 5/0 prolene running sutures

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used to make a 7–8 mm hole into the graft. A 5/0 prolene is used to construct the circular anastomosis. The right coronary anastomosis is next constructed usually as anterior as possible just below the sinotubular ridge of the graft. It is constructed in the same manner as the left (Fig. 8.8). After completion of the distal aortic suture line, delivery of cardioplegia into the aortic root can be used to test the coronary buttons for haemostasis and the aortic root complex can be assessed for function with the LV vent off. This is also an excellent opportunity to test the haemostatic qualities of the internal suture line. If there is any leak either from the suture lines or the valve, we recommend attending this now. This may require taking down the distal aortic suture line and repairing the leak from within. It is also imperative to not distort the distal end of the graft when performing the distal aortic suture line, as this may inadvertently damage valve geometry and integrity (Fig. 8.9). De-airing site is created with a DLP vent, and usual de-­ airing manoeuvres are used prior to release of the cross-­ clamp. Assessment of coronary perfusion is made along with LV filling and dilation with the vent transiently switched off. Next the vent is switched on, and the heart is reperfused for 10-min for every hour of cross-clamp. Standard removal of vent, weaning from cardiopulmonary bypass, decannulation, haemostasis, and repair are carried out. Transoesophageal

Fig. 8.9  Aortic root aneurysm pre- and post-repair following valve sparing aortic root replacement

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echocardiographic assessment of the valve is of paramount importance. If there is any more than mild AR on weaning off bypass, then the patient is placed back on bypass, heart is arrested, and a conversion to a valve replacement within the graft is performed. If there is problematic bleeding, then a Bentall operation is carried out. Bleeding is less of a problem with reimplantation compared to remodelling.

Post-Operative Care Patients are enrolled in life long echocardiographic surveillance usually at 6-weeks post operatively and then annually. Patients typically remain on lifelong beta blockers and aspirin. If on surveillance the patient is found to have increasing valve degeneration, the patient might require valve replacement (although this is very rare in our series and other published outcomes from similar high-volume centres) [2–4].

Conclusions VSARR has robust outcomes in selected patients who would benefit from preservation of the native root. It is best performed by surgeons within centres where there are high volume of aortovascular practice allowing the surgical team to

develop expertise in the operation and surgeons who are proficient in already performing Bentall operations. The successful outcome depends on certain critical operative steps such as graft sizing, assessment of valve leaflet geometry, apposition, and function. The aim being to provide a durable result exceeding an artificial prosthesis.

References 1. Cameron D, Vricella L.  Valve-sparing aortic root replacement with the Valsalva graft, operative techniques. Thorac Cardiovasc Surg. 2005;10:259–71. https://doi.org/10.1053/j. optechstcvs.2005.11.001. 2. Price J, Magruder JT, Young A, Grimm JC, Patel ND, Alejo D, Dietz HC, Vricella LA, Cameron DE. Long-term outcomes of aortic root operations for Marfan syndrome: a comparison of Bentall versus aortic valve-sparing procedures. J Thorac Cardiovasc Surg. 2016;151:330–8. https://doi.org/10.1016/j.jtcvs.2015.10.068. 3. Cameron DE, Alejo DE, Patel ND, Nwakanma LU, Weiss ES, Vricella LA, Dietz HC, Spevak PJ, Williams JA, Bethea BT, Fitton TP, Gott VL. Aortic root replacement in 372 Marfan patients: evolution of operative repair over 30 years. Ann Thorac Surg. 2009;87:1344–50. https://doi.org/10.1016/j.athoracsur.2009.01.073. 4. Beckmann E, Martens A, Krüger H, Korte W, Kaufeld T, Stettinger A, Haverich A, Shrestha ML. Aortic valve-sparing root replacement with Tirone E.  David’s reimplantation technique: single-Centre 25-year experience. Eur J Cardio-Thorac. 2021;60:642–8. https:// doi.org/10.1093/ejcts/ezab136.

9

Minimally Invasive Aortic Valve Replacement Rizwan Q. Attia and Shakil Farid

Interest in minimally invasive aortic valve replacement (MIAVR) has increased after the adoption of transcatheter techniques to treat aortic stenosis and availability of sutureless valves [1]. Numerous minimally invasive surgical approaches for aortic valve replacement have been proposed including upper or lower hemisternotomy, right parasternal minithoracotomy, and transverse sternotomy [2]. Many reports including prospective randomised studies and meta-­ analyses have demonstrated advantages of these incisions, which include reduced pain, reduced surgical trauma, less bleeding, earlier functional recovery, reduced incidence of chest and sternal wound infections, lower incidence of arrhythmias, shorter hospital stay, improved cosmetics, and reduced costs [3].

Surgical Technique: Mini Upper J Sternotomy The patients were anaesthetised in the supine position and intubated with a single-lumen endotracheal tube. Defibrillator pads were placed over the chest wall and back. A transvenous pacing system was inserted at some centres via the internal jugular vein, this is not our standard practice. Transoesophageal echocardiography is used routinely to allow assessment of aortic valve anatomy, annular sizing, de-­airing, and assessment of post-operative valve and cardiac function.

Incision After skin preparation and draping, a 4–6 cm skin incision usually an upper J hemisternotomy through the third or fourth intercostal space is performed (Fig.  9.1). This is guided by the planning aortic CT to allow cannulation of the R. Q. Attia · S. Farid (*) Department of Cardiothoracic Surgery and Transplantation, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected]

right atrial appendage for venous cannulation. A standard hall saw is used from sternal notch down to the third or fourth interspace. Then a small, bladed oscillating saw is used to J into the right intercostal space. Standard haemostasis is performed.

Dissection It is important to have meticulous haemostasis from all soft tissue sites, as the small operative field is unforgiving even for small amounts of blood from soft tissue sites. A small Finochietto retractor is placed, and the sternum is opened. The thymus is divided up to the brachiocephalic vein, and the two lobes are dissected in the midline avascular plane. The pericardium is opened, and the patient is heparinised at this stage. A pericardial well is created with three 1/0 silk sutures on either side through the skin. After the sutures are placed, the sternal retractor is removed and then the sutures are tied. This allows a deep well to be created. On placing the retractor and spreading, it again brings the ascending aorta into view (Fig. 9.2).

Cardiopulmonary Bypass The aorta is cannulated with a standard aortic cannula according to the patient’s body surface area flow requirements. A flat 2-stage venous cannula is placed in the right atrial appendage. Alternatively, a 29/37 FR Trim flex dual stage venous cannula can be inserted through the superior vena cava. A dual lumen DLP cannula is placed in the aortic root for antegrade delivery of cardioplegia and venting the aortic root (Fig.  9.3). Cardiopulmonary bypass (CPB) is established with cooling to 32  °C.  The ascending aorta is cross-clamped and antegrade cold blood cardioplegia is delivered into the aortic root to arrest the heart. Cardioplegia is delivered every 20-min using direct coronary ostia

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_9

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a

b

c

d

Fig. 9.1 (a) Full sternotomy; (b) mini T sternotomy; (c) mini J sternotomy; (d) right anterior thoracotomy

­cannulae. CO2 is flooded into the operative field via a small delivery line to minimise the changes of air embolization.

Procedure Once the heart is arrested, the ascending aorta is opened using a hockey stick aortotomy and the aortic valve excised, sized, and implanted as per standard aortic valve replacement technique. Cardioplegia is repeated at regular intervals by delivering direct ostial cardioplegia. The conduct of the operation is now the same as for conventional valve replacement. In most cases, interrupted pledgeted (or non-­pledgeted) horizontal mattress 2/0 Ethilon sutures are used to implant the valve in an intra-annular or supra-annular position.

Rapid deployment valves can facilitate the procedure and are used as per manufacturers implantation criteria [4]. Typically, a transverse aortotomy has to be performed higher (approximately 3  cm above the sinotubular junction) for a Perceval sutureless aortic valve as it has a higher height profile. Otherwise, the conduct of the operation is the same. For Edwards intuity valve, there is no need to perform a higher aortotomy as the profile is similar to a Perimount Magna Ease bioprosthesis.

Venting A field sucker is used through the aortic valve to vent the left ventricle. Alternative venting strategies included inserting a

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sump sucker through the main pulmonary artery or by inserting a cannula through the right superior pulmonary vein. After the valve replacement, the aorta is closed with two 4/0 Teflon pledgeted prolene sutures. A bipolar ventricular pacing wire and a 24Fr chest drains (drains with perforations such as Blake drain) are placed with the cross-clamp on as the right ventricle is decompressed. In our practice, it is technically much easier to place the drain and pacing wires at this stage. Alternatively, a transvenous pacing wire can be placed during placement of the anaesthetic lines prior to the procedure.

De-Airing

Fig. 9.2  Access to ascending aorta and right atrial appendage for surgical access for CPB cannulation and valve replacement

Fig. 9.3 Upper hemisternotomy with central cannulation for cardiopulmonary bypass

De-airing is extremely important as the heart cannot be mechanically decompressed by the surgeon’s hand. We placed the patient in deep Trendelenburg position, inflate the lungs to expel blood from the pulmonary veins into the left atrium and ventricle so that all air is expelled via the aortic root vent which is placed on high suction. De-airing is guided

Aortic cross-clamp

Dual staged right atrial cannula

Arterial cannula

Antegrade cardioplegia cannula

Retractor

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R. Q. Attia and S. Farid

by TOE.  Once through de-airing is complete, the cross-­ and chest spreading ameliorate the post-operative pain. The clamp is released, and the patient is paced using ventricular use of parenteral narcotics is limited to the first 48 h. In the wires as required. event of significant bleeding or tamponade, re-exploration should be accomplished through the hemisternotomy. A sternal saw and wire cutters are always available in the event of Discontinuation of Cardiopulmonary Bypass emergency re-sternotomy. In general, chest drains are removed according to the local protocol. The patient is The patient is weaned off CPB after a period of reperfusion mobilised prior to drain removal as this helps promote comcommensurate with the cross-clamp times (10-min for every plete drainage from the pericardial cavity. Temporary pacing hour of cross-clamp) and ensuring the normal physiological wires are removed on day 3. Stable patients are aggressively parameters are restored (TRAVEL: Temperature/Rate (pac- diuresed. The aim is to discharge the patient on day 4 post-­ ing check)/Arterial blood gas/Ventilation/Echocardiogram/ operatively. This is achieved by anchoring patient expectaLevelling the table). Standard removal of vent, weaning from tions preoperatively. The patients are reviewed at 4–6 weeks cardiopulmonary bypass, decannulation, haemostasis, and post-operatively, and sternal precautions can be relaxed repair are carried out. Transoesophageal echocardiographic early. The physical restrictions on upper limb range of assessment of the valve is of paramount importance. motion are eased, and heavy lifting is titrated to pain tolerance by week 4.

Closure The sternum is closed with four standard interrupted steel wires. A single steel wire is placed obliquely from the lower end of the sternotomy to the lower end of the intact sternum to ‘lock-in’ the J sternotomy. Standard soft tissue closure with 2/0 vicryl and 3/0 monocryl is undertaken in layers.

Post-Operative Care To achieve the desired benefits of MIAVR, the post-operative philosophy has to be different to conventional surgery. By better preserving integrity of the chest wall, MIAVR is often associated with a faster recovery. To allow early extubation, anaesthesiologists recognise the importance of moderating the dosages of narcotics, sedatives, and muscle relaxants. Either complete or near complete rewarming of the patient is achieved while in the operating room. The limited incision

References 1. Almeida AS, Ceron RO, Anschau F, de Oliveira JB, Neto TCL, Rode J, Rey RAW, Lira KB, Delvaux RS, de Souza RORR. Conventional versus minimally invasive aortic valve replacement surgery: a systematic review, meta-analysis, and meta-regression. Innovations. 2022;17(1):3–13. https://doi.org/10.1177/15569845211060039. 2. von Segesser LK, Westaby S, Pomar J, Loisance D, Groscurth P, Turina M.  Less invasive aortic valve surgery: rationale and technique. Eur J Cardio-Thorac. 1999;15:781–5. https://doi. org/10.1016/s1010-­7940(99)00119-­0. 3. Attia RQ, Hickey GL, Grant SW, Bridgewater B, Roxburgh JC, Kumar P, Ridley P, Bhabra M, Millner RWJ, Athanasiou T, Casula R, Chukwuemka A, Pillay T, Young CP. Minimally invasive versus conventional aortic valve replacement: a propensity-matched study from the UK National Data. IInnovations. 2016;11:15–23. https:// doi.org/10.1177/155698451601100104. 4. Chien S, Clark C, Maheshwari S, Koutsogiannidis CP, Zamvar V, Giordano V, Lim K, Pessotto R. Benefits of rapid deployment aortic valve replacement with a mini upper sternotomy. J Cardiothorac Surg. 2020;15(1):226. https://doi.org/10.1186/s13019-­020-­01268-­y.

Part III Valve Surgery: Mitral Valve Surgery

Surgical Access to the Mitral Valve

10

Francis C. Wells and Narain Moorjani

Reproducible and safe surgery requires both visibility and vision. The first comes through the correct positioning of the patient on the operating table and the maximal utilisation of the surgical incision. The second is harder won and comes with increasing experience and an ever open and questioning mind. Both require a close involvement by the surgeon responsible for the case at all times. There is much contemporary debate about the pros and cons of minimal access or open surgery to reach the mitral valve. This chapter does not set out to explore this conundrum but to give clear guidelines on how to reliably expose the valve through either route.

 ositioning of the Patient on the Operating P Table This is the responsibility of the surgeon in charge of the case. The patient is positioned on the operating table in the supine position. The head should be a comfortable distance from the upper end of the operating table to give good clearance between the anaesthetist’s territory and that of the surgeon. Clashing hands and elbows through the surgical drapes are unnecessary but it is surprising how often it is encountered. If the patient is tall, then it is important to make sure that the feet are properly supported, so as not to allow for the potential of foot drop through over extension of the common peroneal nerve, as it passes around the lateral head of the fibula. Properly designed silicone gel rests should be placed under the dorsal aspect of each lower leg to prevent stasis in the deep soleal plexus of veins.

F. C. Wells (*) Royal Papworth Hospital, Cambridge University Group of Hospitals, Cambridge, UK e-mail: [email protected] N. Moorjani Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK

A similar silicone gel roll is also placed horizontally beneath the patient’s shoulders to push the upper chest forwards. This brings the thorax into a horizontal plane to the operating table. In some patients, especially deep chested men, the diameter of the thorax at the level of the tenth thoracic vertebra is much larger than that at the thoracic inlet. Without this support, the sternum slopes downwards, sometimes at a steep angle and once inside the thorax, the heart tends to fall towards the superior mediastinum. If the inter-­ caval distance is short, this will worsen the access to the left atrium. This simple manoeuvre improves this access. The patient’s arms are comfortably secured to the patient’s side. The essential final check of patient identity and procedure, along with the presence of cross-matched blood and sterile instruments, as laid out in the WHO guidelines, is completed. The patient is then ready for full and careful skin preparation with the chosen antiseptic solution and surgical draping. The surgical team should be present for all of this process.

Surgical Incision For median sternotomy, the skin incision must be central allowing access to the sternal notch superiorly and the xiphisternum inferiorly. The length can vary from the middle two-­ thirds to the full length of the sternum depending upon the experience of the surgeon. Before the sternum is divided, the suprasternal space is developed and a finger is used to free the upper mediastinal space. Similarly, the sub-xiphisternal space is developed with a finger and the xiphisternum divided with heavy scissors. Separation of the sub-sternal tissues for as far as possible, along with interrupting ventilation and disconnecting the endotracheal tube for a moment, will allow the lungs to fall away from the anterior mediastinum, thereby reducing the chance of opening either of the pleural spaces when using the sternal saw. The sternal saw should be allowed to pass through the bone without excessive pressure and following the anterior

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convexity of the sternum. Once divided, the edges of the sternum are sealed with softened bone wax and the periosteal vessels sealed with diathermy. The sternal retractor can then be inserted over drapes to ease the pressure on the edge of the bone. The fat in the anterior mediastinal space is then separated in the midline. The thymic remnant, which is mainly fat in the adult, is separated and any vessels cauterised. Often, however, there are significant vessels within it crossing the midline. These vessels can be clamped on each side, divided and then the tissue within the clamps can be ligated. This will ensure haemostasis. The innominate vein is identified and the thymic vein, which drains into it, identified and clipped, as it is often of significant size. It is important to ensure that the there is no bleeding prior to the institution of cardiopulmonary bypass. During this process, the appropriate dose of heparin is given in preparation for cannulation of the heart for the establishment of cardiopulmonary bypass. The pericardium is then opened along a vertical line two-thirds of the way towards the left side of the visible pericardium. This allows for the pericardium on the right side to be more easily slung under the retractor blades, thus elevating the heart in the pericardial cavity and rotating the left atrium towards the surgeon, thereby improving access. The visceral pericardial reflection between the pulmonary artery and the aorta is then divided, separating these vessels to allow easy application of the aortic cross-clamp. Two aortic purse-string sutures are then placed concentrically, just at the beginning of the arch of the aorta, using a braided polyester suture. The cardiopulmonary bypass tubing is then clamped and divided at an appropriate place so as to allow the tubing to lie comfortably on either side of the sternotomy. The aortic cannula is inserted into the aorta in the centre of the purse-string sutures, which are snugged down to secure the cannula in place. The snugger tubing is then secured to the cannula with a heavy gauge tie to prevent any outward migration of the aortic cannula during the procedure. It is then further secured with a heavy-duty suture to the wound edge, so as to secure the aortic pipe in a gentle curve. Next the venae cavae are cannulated. One purse-string suture is placed around the right atrial appendage and a second just above the inferior cavo-atrial junction. Venous cannulae are chosen depending upon the surface area of the patient. For superior caval cannulation, a gently curved vascular clamp is applied across the base of the atrial appendage. The first assistant then steadies this, and the tip of the atrial appendage is amputated. As the clamp is removed, the venous pipe is slid into the atrium. The retaining suture is gently pulled downwards towards the feet of the patient. This allows easy passage of the venous pipe up into the superior vena cava. Its tip should rest close to the confluence of the innominate vein and the superior vena cava. The snugger is

F. C. Wells and N. Moorjani

then secured and tied to the pipe with a heavy gauge tie. For inferior caval cannulation, the atrial wall is incised in the centre of the purse-string suture with a pointed blade and then gently dilated with the tip of a Robert’s clamp to allow easy passage of the cannula into the atrium. A finger is placed over the hole until the pipe is ready to be inserted. Once the cannula is within the atrium, the first assistant gently retracts the purse-string suture towards the head of the patient and the tube will then pass easily into the inferior cava, as the cranial tension causes the caval valve to flatten against the atrial wall. It is essential that if resistance is encountered, as a result of the venous valve, that undue force is not used, as that can result in a tear to the posterolateral wall of the inferior cavoatrial junction. Once again, the venous pipe is secured to the snugger with a heavy tie (Fig. 10.1). Cardiopulmonary bypass can then be commenced once the pipes are connected to the circuit. A left ventricular vent can then be inserted, via the right superior pulmonary vein or left ventricular apex. The apical approach keeps the operative field free of blood on the ventricular side. A purse-string is then placed in the ascending aorta for the insertion of the cardioplegia line, which again is secured in place using a strong tie. Retrograde cardioplegia is sometimes also used by placement of a purse-string suture on the lateral wall of the right atrium above the inferior vena caval suture. Systemic cooling is then commenced, usually at a systemic temperature of 32 °C. The aortic cross-clamp is then applied with reduced pump flow to minimise the potential for trauma to the aorta. One litre of antegrade cold blood cardioplegia is then a­ dministered.

Fig. 10.1  Operative image illustrating the setup for cardiopulmonary bypass prior to performing mitral valve surgery

10  Surgical Access to the Mitral Valve

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The heart is bathed in cold saline at 4 °C. Using this technique, the heart will arrest rapidly and the ventricle cannot distend, as there is a left ventricular vent in place. Once the heart has been arrested, the superior and inferior vena cavae are mobilised and tapes are passed around each of the cavae. It is done at this stage, as it is very easily done in the arrested heart with no risk of damage to the pulmonary artery superiorly or the back of the inferior vena cava inferiorly.

Exposure of the Mitral Valve Standard Left Atriotomy The standard left atriotomy approach requires mobilisation of Sondergaard’s interatrial groove to reach the intra-atrial septum (Fig. 10.2). Following snaring of the cavae, the caval snares are elevated under some tension bringing the heart a little further

RA IVC

SVC

Incision

4-6 cm

RSPV

RA

SVC

anteriorly in the pericardial space. This also places a little tension on Sondergaard’s interatrial groove at the superior margin of the right superior pulmonary vein. This makes it easier to find the correct place to begin the separation of the right and left atria. All of these small manoeuvres give improved access to the interior of the left atrium (Fig. 10.3). Sondergaard’s interatrial groove is then mobilised to reach the level of the fossa ovalis and an incision is made in the left atrium. The incision is extended cranially beneath the superior vena cava just onto the roof of the left atrium and caudally beneath the right atrium, taking care not to circumcise the inferior pulmonary vein (Fig. 10.4). Care should also be taken not to open the right atrium, which can overhang the left atrium as it approaches the inferior vena caval origin. A further pump sucker is then placed into the left atrium and secured in place with two polypropylene sutures passed through the opened free edge of the left atrium and the parietal pericardium, taking great care not to injure the phrenic nerve by placing them quite high on the pericardium. Self-­ retaining retractor blades can then be inserted into the left atrium to give a very good view of the mitral valve (Fig. 10.5). In addition, placement of annuloplasty sutures prior to any mitral valve repair brings the leaflets closer to the operating surgeon. Through these simple manoeuvres, a satisfactory operative view of almost all mitral valves will be obtained (Fig. 10.6). The left atriotomy is usually closed with a single layer continuous 3/0 polypropylene suture, started at either end of the incision and tied in the middle. In some patients, access to the mitral valve through a standard left atriotomy may be limited, such as in a patient with dense adhesions following previous mitral valve surgery or in patients with a small left atrium. In these patients, alternative approaches need to be considered to access the mitral valve, including a vertical trans-septal bi-atrial incision, superior left atrial roof incision, or horizontal trans-septal bi-­ atrial incision. For some surgeons, these approaches may be the preferred access to the mitral valve.

IVC

Vertical Trans-Septal Bi-Atrial Approach LA

An oblique incision is made from the right atrial free wall through the right atrial appendage and down to the left atrial roof (Fig. 10.7a). This is joined by a second incision through RSPV the fossa ovalis, medial to the crista terminalis, from the Eustachian valve to the edge of the superior limbus Fig. 10.2  Standard left atriotomy approach to the mitral valve with an (Fig. 10.7b). Although this incision affords excellent expoincision made via Sondergaard’s interatrial groove to reach the intra-­ sure to the mitral and tricuspid valves (Fig.  10.7c), it may atrial septum (top); the incision is then extended cranially beneath the require considerable time to close the incision. In addition, superior vena cava just onto the roof of the left atrium and caudally the sino-atrial nodal artery is at risk during this incision. beneath the right atrium (bottom)

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b

Fig. 10.3  Operative images demonstrating (a) mobilisation of the superior vena cava and (b) tension placed on the caval snuggers to raise a line of tension at the superior margin of the right superior pulmonary vein

artery, non-coronary sinus of aorta, and superior vena cava are at risk due to their proximity to the incision.

Horizontal Trans-Septal Bi-Atrial Approach A horizontal incision is made between the right superior and inferior pulmonary veins across the free wall of the right atrium (Fig. 10.9a). The incision is then continued across the interatrial septum through the fossa ovalis and the left atrial free wall (Fig. 10.9b). Again, although it offers good access to the mitral and tricuspid valves (Fig. 10.9c), it can be difficult to close.

Minimal Access Approaches to the Mitral Valve Fig. 10.4  Operative image demonstrating mobilisation Sondergaard’s interatrial groove and incision into the left atrium

of

Superior Left Atrial Roof Approach An incision is made across the right atrial free wall and continued between the superior vena cava and the right atrial appendage (Fig. 10.8a). From there, it is extended across the interatrial septum and the roof of the left atrium passing behind the aortic root towards the commissure between the left coronary cusp and the non-coronary cusp (Fig. 10.8b). Although this incision gives good access to the mitral valve (Fig. 10.8c), the roof is the weakest part of the left atrium and this tissue can be relatively friable when closing the incision. In addition, the sino-atrial node artery, left main coronary

Following general anaesthesia with a single-lumen endobronchial tube and placement of external defibrillation pads, the patient is positioned supine with slight elevation (30°) of the right chest, using an inflated pressure bag (Fig. 10.10). The right femoral artery and vein are exposed through a 3 cm groin crease incision and cannulated using a Seldinger technique, supported by 5/0 polypropylene purse strings (Fig.  10.11). The arterial cannula sits in the common iliac artery, whilst the venous 3-stage cannula positioned in the inferior vena cava, right atrium, and superior vena cava, under TOE guidance. Additional venous drainage can be obtained with a second venous cannula inserted percutaneously through the right internal jugular vein, especially in patients requiring

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Fig. 10.5  Operative images demonstrating the self-retaining mitral valve retractor blades in situ from the (a) superior aspect of the operating table and (b) right side of the operating table

Fig. 10.6  Operative image demonstrating surgical view of the mitral valve following insertion of self-retaining retractor blades and annuloplasty sutures

concomitant tricuspid valve surgery or with an increased body surface area. Vacuum-assisted cardiopulmonary bypass is used with mild hypothermia (32–34 °C). There are a number of minimally invasive incisions described in the literature ranging from a right thoracotomy of vary sizes giving direct access to the mitral valve to a periareolar incision using a completely endoscopic tech­ nique. One example is performing a 5–7 cm right anterolateral thoracotomy in the fourth intercostal space in the submammary fold followed by insertion of a soft tissue retractor. A 10-mm thoracoport is then placed in the right fourth intercostal space in the mid-axillary line for insertion

of the 30° camera and in the sixth intercostal space in the anterior axillary line for insertion of the pump sucker. Following initiation of cardiopulmonary bypass, an inverted C-shaped incision is made in the pericardium anterior to the right phrenic nerve and access to the heart is facilitated by pericardial and diaphragmatic retraction sutures, as required. An additional 3 mm stab incision is placed in the right second or third intercostal space in the anterior axillary line, through which a Chitwood aortic cross-clamp is inserted. Following aortic cross-clamping, antegrade cardioplegia is delivered through a long 35 cm cardioplegia cannula, inserted into the right lateral aspect of the ascending aorta (Fig. 10.12). Alternatively, an endoballoon can be used to occlude the ascending aorta, with an internal channel to deliver antegrade cardioplegia, which is passed via the femoral artery. In such instances, right radial artery monitoring is used to be certain that balloon migration and innominate artery obstruction have not occurred. Retrograde cardioplegia can also be delivered through a percutaneous trans-jugular catheter placed in the coronary sinus under TOE guidance. Carbon dioxide is administered at 4  L/min via the camera port throughout the procedure. Access to the mitral valve can be obtained through a standard left atriotomy, or right atrial trans-septal approach if tricuspid valve disease is also present. Specialised surgical instruments, including a left atrial retractor, are then used to perform the majority of standard mitral valve surgical techniques. De-airing is performed using aortic root suction and by distending the left atrium during closure, with TOE guidance.

60 Fig. 10.7  Vertical trans-­ septal bi-atrial approach to the mitral valve with (a) an incision made across the right atrial free wall through the right atrial appendage and down to the left atrial roof; (b) the incision extended across the interatrial septum through the fossa ovalis; and (c) giving excellent access to the mitral and tricuspid valves

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a

Antegrade cardioplegia Aortic cannula SVC cannula with snare IVC cannula with snare

Right atriotomy incision

b

Fossa ovalis Tricuspid valve Ostium of coronary sinus

Incision across atrial septum

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Mitral valve

Tricuspid valve Cardioplegia cannula in the coronary sinus

Right atrium

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c c

Fig. 10.8  Superior left atrial roof approach to the mitral valve with (a) an incision made across the right atrial free wall and continued between the superior vena cava and the right atrial appendage; (b) the incision extended across the interatrial septum and the roof of the left atrium passing behind the aortic root; and (c) giving excellent access to the mitral and tricuspid valves

Fig. 10.9  Horizontal trans-septal bi-atrial approach to the mitral valve with (a) an incision made between the right superior and inferior pulmonary veins across the right atrium; (b) the incision extended across the interatrial septum through the fossa ovalis; and (c) giving excellent access to the mitral and tricuspid valves

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Fig. 10.10  Positioning of the patient prior to minimally access mitral valve surgery, with the skin incision and positioning of ports marked onto the anterior and lateral chest wall and the patient placed with the right chest elevated to 30°, using an inflated pressure bag

F. C. Wells and N. Moorjani

Fig. 10.12  Operative setup for minimally invasive mitral valve surgery, following aortic cross-clamping and delivery of antegrade cold blood cardioplegia

third intercostal space in the anterior axillary line and the right trocar in the sixth intercostal space in the anterior axillary line, avoiding any internal and external arm conflicts. The 3-D high-resolution endoscope is placed through the medial portion of the mini-thoracotomy, with the other instruments passed through the remainder of the incision.

Fig. 10.11  Cannulation of the right femoral artery and vein

Robotic Mitral Valve Surgery Robotic mitral valve surgery can be performed either as port access surgery with robot assistance using a 3–4  cm right submammary incision, or as a robot-performed totally endoscopic procedure using a 15 mm ‘working port’, placed in the right fourth intercostal space in the anterior axillary line. The robotic camera is placed in the right fourth intercostal space just lateral to the mid-clavicular line. Otherwise, the initial setup for robotic surgery is similar to videoscopic mitral valve surgery with respect to femoral cannulation and antegrade intra-aortic cardioplegia. Following opening of the left atrium, the positions of the left and right robotic instrument arms are determined to provide optimal visualisation of the mitral valve. Commonly, the left trocar is placed in the

Robotic mitral valve surgery requires a number of components, including • An endoscope, which consists of two parallel cameras, channelled to each of the operator’s eyes, providing up to 10 × magnification in 3D. • Miniaturised standard surgical instruments, mounted on long thin shafts, which provide tremor-free movement through multiple degrees of freedom. • Bedside unit, with articulating arms that allow the endoscope and instruments to be electronically controlled at the surgeon’s console. • Surgeon’s console, which comprises of: –– A viewing screen, which provides true 3-D vision with improved visualisation. –– Two hand controllers, which directly translate the hand and finger motions of the surgeon to the instruments. –– A series of foot pedals, which allow camera focus, movement of instrument supports, and electrocautery.

Suggested Reading Barac YD, Glower DD. Port-access mitral valve surgery-an evolution of technique. Semin Thorac Cardiovasc Surg. 2020;32(4):829–37. Chitwood WR Jr. Robotic mitral valve surgery: overview, methodology, results, and perspective. Ann Cardiothorac Surg. 2016;5(6):544–55. Glower DD.  Surgical approaches to mitral regurgitation. J Am Coll Cardiol. 2012;60(15):1315–22.

Surgical Correction of Degenerative Mitral Valve Disease

11

Francis C. Wells

Degenerative mitral valve disease is a common cardiac lesion. Presentation is most commonly in late middle and old age. As the name suggests, it is a result of the wear and tear generated through decades of high-pressure stress on valve leaflets malformed to carry the load. This will become clear when the anatomy of the valve is considered. The left atrioventricular valve, referred to as the Mitral valve (the sixteenth century anatomist, Andreas Vesalius would seem to be the first person to ascribe the name Mitral to the valve, opining that it appeared to him to be similar to an inverted bishop’s Mitre), is a complex structure. It has a dual function. First, to render unidirectional flow through the left side of the heart and second to support the geometry of the left ventricular cavity through the cardiac cycle. In the case of a failing valve, stenotic or regurgitant, simple excision will result in altered ventricular systolic and diastolic function. Dr. Walter Lillehei first reported this phenomenon in a seminal paper in 1964 [1]. Complete excision of the valve leaflets and their supporting cords resulted in early ventricular failure in spite of a well-functioning replacement valve. Therefore, a key component of either valve reconstruction or replacement is the retention or reconstruction of the sub-valve connections. Mitral valve reconstruction retains the normal force distribution on the leaflets and the support of the ventricle. The insertion of a synthetic valve with cordal and papillary muscle retention will alter the alignment in relation to the ventricular wall but this seems not to visibly alter ventricular performance. However, retrospective data would seem to indicate that valve replacement even with sub-valve preservation results in earlier and worse mortality than in mitral valve repair, particularly in the elderly [2].

F. C. Wells (*) Royal Papworth Hospital, Cambridge University Group of Hospitals, Cambridge, UK e-mail: [email protected]

Table 11.1  Carpentier functional classification of mitral valve lesions Type 1: Orifice dilatation or leaflet perforation Type 2: Excessive leaflet motion: elongated and/or ruptured cords and papillary muscles Type 3: Restrictive leaflet motion: rheumatic/calcific valve with fixed leaflets, fused and shortened cords and papillary muscles or functional distortion of LV wall in ischaemic or cardiomyopathic disease sates

This observation and the imperfect solution of prosthetic valve replacement have led to a significant move towards valve reconstruction. Although the earliest attempts to manage mitral regurgitation included various techniques for valve retention, it really was the seminal work of Professor Alain Carpentier that brought mitral valve repair into the main stream and the gold standard treatment. His methodical approach based upon a structural classification of lesions gave a foundation for decision-making enabling surgeons to discern the most appropriate surgical solution for individual lesion sets [3]. Table  11.1 shows the Carpentier classification.

Type 1 Lesions Orifice dilatation results from traction on the atrioventricular junction by a dilating left ventricle (LV) or left atrium (LA). Primary causes of LV stretch are various forms of cardiomyopathy. Secondary causes are volume overload as in aortic valve regurgitation or mitral regurgitation. Ischaemic fibrosis in the ventricular wall can also lead to ventricular dilatation. Infero-basal ischaemia will often lead to fibrosis in the wall at the origin of the papillary muscles causing their distortion and hence leaflet distraction. These secondary causes can be corrected by a number of different approaches which are dealt with in another chapter.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_11

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Type 2 Lesions Type 2 lesions comprise the degenerative group. The mitral valve can be thought of as the lynch pin (a structure, person or thing vital to normal function) within of the left ventricle. As was mentioned in the opening to this chapter, the continuous loop of leaflets, cords, papillary muscle, and ventricular wall returning to the origin of the leaflets at the base of the ventricle at the atrioventricular junction form a support for the ventricular chamber of profound importance. At the end of systole, the valve leaflets are bearing very high closing pressures which must be distributed evenly across the valve leaflet surfaces. Any interference with this force distribution will cause excess stress loading on the relatively unsupported part of the valve. This is caused by malformations of the components of the valve. Abnormal distribution of papillary a

muscles from their normal horseshoe shape will alter load sharing and result in uneven load spread. Also, deep clefts to the annulus in the mural leaflet interrupt load sharing and again will cause excess loading per surface area. It is almost the rule that either side of a mural leaflet prolapse will be deep clefts with often abnormal papillary muscle support; the P2 segment being the most common (Fig. 11.1). The mitral leaflets are arbitrarily divided into three parts (Fig. 11.2). The competent mitral valve depends upon an even area of coaptation of leaflet commissures of approximately 0.8 cm in height (Fig.  11.3). Restoration of uniform coaptation of leaflets is the bed-rock of mitral valve reconstruction/repair. Uniform use of the lexicon in mitral valve disease is important for consistent reporting and discussion.

b

Fig. 11.1 (a, b) Abnormal papillary muscles and associated cords in patients with severe mitral regurgitation

Fig. 11.2  Segmentation of the mitral valve leaflets for the purpose of lesion description

x A3

A1

A2 P1

P3 P2

11  Surgical Correction of Degenerative Mitral Valve Disease Fig. 11.3  The length of opposing leaflets is referred to as the coaptation height shown here from (a) to (b)

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a

b

a-b. : coaptation height

Definitions Leaflet prolapse: Abnormal displacement of the leaflet beyond the plane of the valve. Flail leaflet: Wild and/or erratic movement of the leaflet with ruptured cord(s). Billowing valve: Leaflet body has a soft upward curve beyond the plane of the annulus. Barlow’s valve: A valve that is significantly larger than the normal with orifice area of up to 40% greater. Leaflets have multiple scallops and are thickened with often multiple areas of prolapse. Myxomatous valve (often associated with a Barlow’s valve): Thickened leaflets billowing or prolapsing beyond the plane of the annulus. Whilst mural leaflet prolapse is the most frequent lesion (>60%), aortic and bileaflet prolapse are also seen frequently in significant mitral practices. Of those, central mural leaflet prolapse is the most common. Prolapse of this segment is commonly associated with ruptured tendinous cords. This will result in a flail leaflet everting into the atrial cavity (Fig. 11.4). Commissural prolapse is the term used (inaccurately by strict definition) to describe the prolapse of anterior–superior or infero-lateral ends of the aortic and mural leaflets. The correct use of the term commissure is the location at which two objects meet; in the context of heart valves, in this case the mitral valve, it describes the meeting of the two leaflets throughout their length, not, as is commonly thought, as the two ends of the leaflets, however the former use of ‘commissure’ has irreversibly entered the lexicon. Aortic and bileaflet prolapse are commonly found in Barlow’s disease. This condition is accompanied by a valve

orifice up to 40% greater than normal with significant excess leaflet tissue. There are, commonly, multiple deep clefts in the mural leaflet and also in the aortic leaflet (Fig. 11.5). There are several combinations of lesions of the mitral apparatus that are often found together. Each valve demands individual analysis on preoperative echocardiogram but particularly at operation. The phenomenon of echo ‘drop-out’ may camouflage secondary and tertiary lesions. This is when a larger lesion overshadows a lesser one, thereby interrupting the echo return from the secondary lesion. As mentioned earlier, the restoration of full and even coaptation is the goal of repair. Therefore, it is important to remedy all lesions found. Leaflet coaptation is eroded by ventricular and/or atrial dilatation resultant upon the dilating effect of increasing volume overload. As coaptation height reduces the base of the left ventricle begins to move outwards further pulling on the atrioventricular junction. If bileaflet prolapse progresses, it can give rise to the appearance of the mural leaflet arising from the wall of the atrium and not the usual junctional anatomy. Recently, this has received the term mitral annular dysjunction or M.A.D. Once full coaptation is restored normal motion of the atrioventricular junction is restored with downward descent of both leaflets into the ventricular chamber at the end of systole. The modern mitral surgeon has many tools in the surgical toolbox. The most frequently used are listed here and will be discussed and illustrated in the following text. 1.

Leaflet resection (a) Quadrangular resection (b) Quadrangular resection plus sliding annuloplasty (c) Triangular resection (d) Leaflet height reduction

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a

Ruptured cord

b

Fig. 11.4 (a, b) Ruptured cord with flail segment

2. Cordal replacement 3. Commissural plication 4. Alfieri edge-to-edge technique 5. Annular decalcification 6. Leaflet transfer The choice of surgical procedure depends both upon the lesion and surgeon preference. For example, the prolapsing/ flail mural leaflet may be managed with leaflet resection, cordal replacement, or by edge-to-edge sutures.

Valve Exposure

Fig. 11.5  Barlow’s valve revealing multiple deep clefts, excess leaflet tissue, and prolapsing leaflets. Note the variation in height of the leaflet segments

Minimal access procedures will be discussed elsewhere. My preferred access is via a mid-line sternotomy with bi-caval cannulation. The heart is arrested with intermittent antegrade cold blood cardioplegia (Fig. 11.6). An incision is made posterior to the interatrial groove. It is extended superiorly underneath the superior vena cava, and inferiorly underneath the inferior vena cava until the atrial wall turns upon itself superiorly (Fig. 11.7).

11  Surgical Correction of Degenerative Mitral Valve Disease

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b

c

Fig. 11.6 (a–c) Mid-line sternotomy with bi-caval cannulation, antegrade cardioplegia, and external cold

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Fig. 11.7  The incision into the left atrium below the interatrial groove, exposing the inside of the atrium and the mitral valve. A sucker is secured in the left atrium to aspirate any returning blood

The Annulus Once the mitral valve is exposed, it is advisable to place interrupted sutures around the annulus (annuloplasty sutures), from Trigone to Trigone, as a first step. This pulls the valve into an even plane and enhances the view of the valve rendering the components of the valve in anatomical proportion. The placement of the annuloplasty sutures is very important. The needle should be at right angles to the tissue and pass vertically downwards into the ventricular muscle followed by a rotation of the wrist to bring the suture out of the tissue in an even curve so as not to convert the penetrating needle hole into a linear tear (Fig. 11.8). There is a wide choice of annuloplasty devices. The principal choices are between rigid and flexible complete rings or partial bands. The reasons for implanting annular support are first to reduce the orifice area of the valve to ensure optimal coaptation and second to stabilise the atrioventricular junction into the future. During the procedure, the presence of the sutures under the weight of the restraining clips reduces the orifice by as much as 10%. On completion of the

Fig. 11.8  Note the angle of the needle to the tissue. Its entry should be at 90° to the tissue

structural repair and testing the result by filling the ventricle under tension, the resulting coaptation height can be visualised by marking the atrial margin of coaptation with a sterile marking pen (Fig. 11.9).

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a

a

b

b

Fig. 11.9 (a, b) The line of coaptation marked with sterile blue ink. The tensioned valve has been marked at the coaptation margin to reveal the depth and evenness of coaptation throughout the length of the commissure

The choice of annuloplasty band size can then be based upon the full surface area of the closed and tensioned valve and not just the aortic leaflet as proposed by some (Fig. 11.10). Atrioventricular dilation occurs along the free left ventricular portion of the valve orifice and not the aorto-mitral cur-

Fig. 11.10 (a, b) The valve is tensioned so that the ascending aorta proximal to the aortic clamp is tense and the band size is chosen based on the full surface area of the tensioned valve

tain portion which does not stretch. Hence there is no rationale for a complete ring. In addition, the base of the ventricle is mobile throughout the cardiac cycle hence inherent flexibility in the chosen band can be argued to be an advantage. A partial band must extend from Trigone to Trigone and not commissure to commissure to ensure long-lasting prevention of annular re-expansion (Fig. 11.11).

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b

Fig. 11.11 (a) Placement of annuloplasty sutures from Trigone to Trigone. (b) Flexible annuloplasty band secured in position

Leaflet Techniques

mitral stenosis may result. This may only be detectable on exercise.

Quadrangular Resection of Mural Leaflet This technique, first popularised by Professor Alain Carpentier involves a reduction of the mural annular circumference to compensate for the excised tissue (Figs. 11.12 and 11.13). Imaginary radial lines are drawn from the centre of the aorto-mitral curtain, either side of the prolapse and that segment is excised. Sutures (1–3) are placed across the resected portion and pulled outwards to re-oppose the annular edges, thereby shortening the annulus (see Figs.  11.11 and 11.2). The flexible annuloplasty band is then inserted and the fully repaired valve finally tested. This long-established procedure for mural leaflet prolapse, stabilised with an annuloplasty ring, has stood the test of time and remains a mainstay of mitral reconstructive surgery. The limitation of the procedure is the reduction in valve opening area which can be significant and if not appreciated

Sliding Annuloplasty If, during a quadrangular resection, a larger leaflet resection is required, then the tension on the reattached leaflet edges will be too great. To surmount this, the annulus can be shortened in the region by this technique. After the quadrangular resection has been done, each side of the mural leaflet is detached from the annulus; in other words, undermining the leaflets for 1–2 cm. on either side. This length of annulus can then be longitudinally plicated reducing this part of the circumference bringing the cut edges of the leaflets back together. The leaflets can then be reattached to the annulus and to each other (Fig. 11.14). The annuloplasty band, if one is used, can be held by the tied annuloplasty sutures already through the annulus. If the length of leaflet undermining is long, almost to each end of the commissures, then a band may not be necessary.

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11  Surgical Correction of Degenerative Mitral Valve Disease Fig. 11.12 (a) Lines of intended resection. (b) Quadrangle of leaflet tissue excised with the base wider than the leading edge. (c) Annulus fully retracted and the annuloplasty sutures ligated. The divided leaflet edges are sutured with interrupted or running 4′0′ Proline™

a

Imaginary radial lines from topcentre to annulus.

Excised portion

b

Resected magins

Annuloplasty sutures

Annulus retracted at reseded margin

c

Leaflet re-approxed with 4 ‘O’proline

Retracted annulus closed with 2’0’ with ethibond sutures

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a

b

Fig. 11.13 (a, b) The annulus is retracted for the annuloplasty. The retracted annulus has been closed and the leaflet re-apposed

Triangular Resection Where the prolapsing segment of leaflet is voluminous, with a surface area that is greater than the distance between the non-prolapsing portion, an alternative approach is a triangular resection. Here the base of the triangular resection is at the leaflet edge. The depth of the resection into the leaflet will be determined by the breadth of the prolapsing segment (Figs. 11.15 and 11.16). With a voluminous leaflet, this technique can work well, however, if too much leaflet is resected, the sutured leaflet can draw the edges of the segment away from the leaflet segments on either side giving rise to a leak through the clefts. This may be compensated for by a smaller size annuloplasty band, however if there is a suspicion that this may be the case then alternative methods will be better employed. If there is a paucity of cords at the margin of the reconstructed leaflet, then a Gore-Tex neo cord may be placed at the apex of the repaired leaflet and drawn down to the appropriate height. This procedure is a development of the original imbrication technique described by Dwight McGoon [4].

Leaflet Height Reduction The mitral valve leaflets arise from cushions of tissue at the atrioventricular junction whilst the heart is a tube in the early foetus. These cushions grow into projections that become the leaflets. The junctions of the cushions form the clefts in the leaflets. If growth is retarded at those sights, then deep clefts are left, frequently reaching to the annulus (Fig. 11.17).

Cords will still arise from the edge of the leaflets within these indentations giving proof of their congenital origin. The outward growth of the neo-leaflets may be variable as well, with excessive growth frequently found in the P2 region, but also (although somewhat less frequently) in other parts of the mural leaflet (Fig. 11.18). These tall leaflets—often unsupported on each side as result of the deep clefts—are vulnerable to high stress loading in systole, which may result in leaflet prolapse. As these portions frequently have cords that are widely separated, it is common to find prolapse of these areas in the absence of chordal rupture. The depth of these portions of the mural leaflet is frequently equal to that of the aortic leaflet. If this is not considered and dealt with at operation, the placement of an annuloplasty ring will bring about early contact between the leaflets in early systole, and the reverse folding of the aortic leaflet into the outflow tract of the left ventricle in midto late systole, causing outflow tract obstruction and mitral regurgitation. This is referred to as abnormal systolic motion of the anterior leaflet or S.A.M. for short. There are ways to prevent this as long as the surgeon is aware of the potential problem; these are (1) reduction of the mural leaflet height, and (2) the placement of extremely short neo-cords pulling the leaflet almost to the ventricular wall and the use of a large annuloplasty band so as not to reduce the orifice area more than is needed to produce leaflet coaptation of 0.8  cm. Excessive traction of the mural leaflet into the ventricular cavity turns the valve into a mono-leaflet valve. Whilst this may be effective, it is anti-physiological and may lead to unnecessary extra strain on the aortic leaflet which may give rise to aortic leaflet prolapse at a future time. It is my prefer-

11  Surgical Correction of Degenerative Mitral Valve Disease Fig. 11.14 (a–c) Sliding annuloplasty. The edges of the incised leaflets are undermined on each side and the corresponding annulus shortened by tying each of the annuloplasty sutures. The leaflets are then reattached to the annulus and to themselves

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a A

A: Aortic leaflet

Lines of undercut

b

Stay Suture

Leaflets underwined

c

• Leaflet edges apposed • Annuloplasty sutures tied • Leaflet reattached to annulus • Annuloplasty band about to slide in to place.

F. C. Wells

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a

Triangular resection

Area for resection

b

c

Leaflet with resection

d

e

f

g

Leaflet edges sutured together

Fig. 11.15 (a–g) The excess tissue to be resected is marked out and then removed. The cut edges are then sewn together, either with continuous or interrupted sutures

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a

b

c

d

Fig. 11.16 (a–d) Another example of a triangular resection Fig. 11.17  A deep cleft in the mural leaflet extending to the annulus

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a

c

F. C. Wells

b

d

Fig. 11.18 (a–c) Disproportionately and excessively tall mural leaflets. (d) 3-D echo modelling of the prolapsing segments (three different valves)

ence to reduce the height of the mural leaflet to restore the normal height ratio of one third of the height of the aortic leaflet and then to place an appropriately sized annuloplasty band to optimise coaptation and permanently stabilise the repair (Figs.  11.19, 11.20, 11.21, 11.22, 11.23, 11.24 and 11.25). The excised portion should take the form of a blunted trapezoid and not an oval. If an oval is excised when the leaflet is drawn back to the annulus, it will tend to open up any cleft with the leaflet portion next to it and cause a leak between the edges. The trapezoidal resection leaves more tissue to abut the leaflet next to it (Fig. 11.26). With the leaflet reconstructed, it may be necessary to add neo-Gore Tex™ cords (see later section) (Fig.  11.27). The appropriately sized band is then placed from Trigone to Trigone sizing it on the whole surface area of both leaflets with the valve tensioned by a full ventricle.

Fig. 11.19  The base of the leaflet is incised with a knife. The incision can be completed with scissors

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77 Incised margin

P2

P1

P3

Atrioventricular fat

Mural leaflet detachment from annulus

Fig. 11.20  The base of the leaflet is incised with a knife. The incision can be completed with scissors

Fig. 11.23  Fat can often be seen in the atrioventricular junction after detachment

Fig. 11.21  The base of the leaflet is incised with a knife. The incision can be completed with scissors

Fig. 11.24  The suture line is begun

Fig. 11.22  Fat can often be seen in the atrioventricular junction after detachment

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F. C. Wells

lary muscle and the leaflet in both directions (Fig.  11.31). When tied they will not slip and the knot will disappear under the leaflet when the valve is tensioned.

Commissural Prolapse In this situation, both the aortic and mural leaflets are ­prolapsing at the end of the commissure. This is most commonly found at the junction of the infero-lateral end of the commissure (Fig. 11.32). There are several ways of dealing with this but one is illustrated in Fig. 11.33).

Alfieri Edge-to-Edge Technique

Mural leaflet reattached to annulus with 2-nes Cord, to leading edge

Fig. 11.25  The completed repair with new cords to the leading edge

Cordal Replacement Ruptured, stretched, or inadequate cord numbers can be replaced by the use of 4′0′ Gore Tex sutures™. These are placed through the appropriate papillary muscle head with two passes (Fig. 11.28) and then through the leading edge of the leaflet where needed, again with 2 passes per end of the suture; as many sutures as are needed are used (Fig. 11.29). The leaflet is then reduced to the appropriate height and tested (Fig.  11.30) and then tied. To prevent them slipping once the correct length has been chosen each end of the suture is passed behind the pair of sutures between the papil-

This surgically simple solution is used primarily as a bail-out manoeuvre for valves that the surgeon may feel are too complex to repair. Complex Barlow’s valves are often managed by some surgeons in this way. Originally described by Professor Alfieri having come across a natural valve where the centre of the valve leaflets had fused in development, it was originally described in the context of additional annular reduction with the placement of an annuloplasty ring/band [5]. It was named the edge-to-edge technique but this does not accurately describe the placement of the sutures to achieve lasting competence. Here the opposing edges of the leaflets are sewn directly together across the commissure in the region of the prolapsing segments. The sutures must pass as deep as the secondary cords with the first pass of the needle and then through the leading edges (Fig.  11.34). The suture is then tied turning the single mitral orifice into a double orifice valve. The repair is then stabilised with an annuloplasty ring. This is the basis of the Mitraclip™ percutaneous method of repair, where instead of a suture one or more clips are applied to fix the leaflets together. A commissural prolapse can also be repaired in this way but care must be taken

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a i

ii

Resultant force opens the cleft Oval excision

b i

ii

a b a>b Resultant force closes the clefts

Trapezoid excision

Fig. 11.26  Trapezoidal resection of the base of the leaflet after detachment from the annulus. This reduces the height but also pushes the edges of the restored leaflet towards the portion of leaflet next to it allowing good coaptation between segments either side of the cleft

Fig. 11.27  Trapezoidal resection of the base of the leaflet after detachment from the annulus. This reduces the height but also pushes the edges of the restored leaflet towards the portion of leaflet next to it allowing good coaptation between segments either side of the cleft

Fig. 11.28  Gore-Tex suture being passed through the papillary muscle head

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a

b

c

Fig. 11.29 (a–c) Gore-Tex sutures passed through the leading edge of the leaflet

a

b

Fig. 11.30 (a) Neo-cords in place ready to be tied down and the leaflet is lowered to the appropriate height. (b) The valve is then tested to assess the result

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b

Fig. 11.31 (a, b) The sutures are then passed behind the afferent limbs of the suture and tied

Fig. 11.32  Infero-lateral commissural prolapse

F. C. Wells

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a

Commisural prolapse

b

Hatch the resected Commisural leaflet

c

Annulus drawn outwards

A3

Annuloplasty sutures

A3

A3 Incision

P3 P2/3

d

P2

P3

Leaflet margins drawn together

e

Reconstituted leaflets sewn back to neo-annulus Annuloplasty ring

Fig. 11.33 (a–e) Each side of the prolapse is cut away from the annulus, and the triangular corners are excised. The annulus is then drawn backwards and sutured to itself, reducing the circumference of the

annulus and the leaflets sewn back to each other. (f–h) The whole procedure is then stabilised with an annuloplasty band

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f

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g

h

Fig. 11.33 (continued)

Alfieri Edge to edge technique.

A

M

A: Aortic M. Mural

Fig. 11.34  Alfieri edge-to-edge technique. Sutures pass through each opposing leaflet at the centre of the prolapse with the first pass at the level of the secondary cords

not to narrow the orifice too much so as to produce mitral stenosis. It is advisable to add an annuloplasty band to prevent later annular dilatation.

Annular Decalcification and Reconstruction It is quite common to find calcification at the hinge of the atrioventricular junction along the line of the mural leaflet. It occurs as a result of the excessive motion of the prolapsing leaflet and is found commonly in the Barlow’s valve. This can be a short distance centred on the P2 region or in extreme can extend for most of the orifice of the valve with extension into the aorto-mitral curtain extending into calcification of the aortic valve (Fig. 11.35). This can be the case with quite mobile and uncalcified leaflets making it the opposite of the calcification found in rheumatic disease, where the primary changes are in the leaflets and the papillary muscles and the cords. In such situations whether valve replacement or valve repair is planned, the calcified tissue is best removed. However considerable experience is needed to carry this out

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safely as rupture of the posterior wall of the ventricle can occur if it is not done properly. Hence, it should be carried out by experienced surgeons or under the direction of one with experience.

Technique Begin the process with a sharp incision into the endocardium on the atrial side at the junction of the calcified tissue with the calcium (Fig. 11.36). This is extended for the length of the calcified portion. The calcified block can then be teased away from the ventricular muscle with a combination of knife and scissors. It is usually possible to remove it in one block (Fig. 11.37). Occasionally the use of a Rangeur will help. The one area that it is important to stay away from is

F. C. Wells

the P1/A1 region extending towards the outflow tract of the left ventricle. Extension of the removal into this area runs the real risk of disassociation of the muscle underneath the left atrial appendage with fatal results. This area of muscle will separate and blood infiltrating under pressure will burst through underneath the left atrial appendage and is almost impossible to repair. Once the calcified block has been removed, it is essential to cover the area with a large and loose pericardial patch to prevent disruption of the posterior wall of the ventricle through the now exposed muscle. The patch will be large to prevent tension on the posterior wall when the ventricle is functioning. The sutures in the ventricular muscle should be deep and large bites through undisturbed muscle (Fig. 11.38). Sometimes there is enough excess tissue in the mural leaflet for it to be reconstituted (Fig. 11.39). The annuloplasty

Ca++

Begin the incision at junction with atrium

Fig. 11.36  The beginning of the incision into the endocardium at the base of the calcified mass

Fig. 11.35  Radiograph of severe mitral annular calcification. In this case almost circumferential

a

b

Fig. 11.37 (a, b) First incision to remove the calcified mass on the atrial side right on the reflection of the endocardium from the mass

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a P1

P2 leaflet

P3

Seperated leaflet

Ventricular muscle Fat

b

Calcified spur

Ca+ annulus

Pericardial patch

Ca++ resected Exposed muscle in fat

Cortex cords

Pericardial patch with leaflet reattached Fig. 11.38 (a, b) The calcified mass has been removed revealing the interatrial groove fat and exposed muscle. The mural leaflet has been separated from the calcified area. In (b), there was a calcified spur extending into the leaflet which was then excised and the bare area patched

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a

Fig. 11.39 (a, b) A generous pericardial patch has been sewn into position with no tension. The sutures for valve insertion are seen in place in (b). In the first case (a), there was enough leaflet to reattach the

F. C. Wells

b

detached leaflet to the neo-atrioventricular junction. Gore-Tex cords were then inserted to the leading edge of the leaflet

sutures should be placed through the junction of the pericardial patch and the atrial wall prior to reattachment of the leaflet. If valve replacement is deemed necessary then again, the sutures are passed through the patch and the atrial wall. This will give a secure base for the valve annulus to be tied against.

Barlow’s Valve An extreme example of the Barlow’s deformity is shown in Fig. 11.40. Here almost all regions of the valve are prolapsing and have multiple clefts. Whilst bileaflet prolapse is common in this setting, there are many cases where the aortic leaflet becomes unsupported as a result of severe mural leaflet prolapse. In this setting restoring mural leaflet competence, with reduction of the annular circumference with an annuloplasty band will reveal that the aortic leaflet is not actually prolapsing. These are cases where all of the tools in the surgeon’s box may be required, leaflet resection, leaflet height reduction, the use of neo-cords, etc. Experience is the key to satisfactory results in these cases. Often multiple neo-­ cords are needed to both leaflets. These are cases where significant experience in the art of mitral surgery is needed. The billowing nature of these valves leaves the surgeon with a lot of excess leaflet tissue that can be used to obtain optimal results. It is important not to reduce the valve circumference any more than is necessary to give good leaflet coaptation as S.A.M. can easily be produced.

Fig. 11.40  An example of severe Barlow’s valve with ruptured cords and multiple areas of prolapse and billowing leaflets. It was possible through a variety of techniques to reconstruct this valve

Endocarditis of the Mitral Valve It is often possible to reconstruct endocarditic valves once all infected material has been removed (Fig. 11.41). It is important to be sure that excision is complete. Only then can it be decided which reconstruction method may be applicable or whether valve insertion is needed. Appropriate antibiotic therapy should be continued for 6  weeks intravenously if infected material is found at the time of surgery. As with Barlow’s disease, the surgical techniques needed to resolve

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b

c

d

e

Fig. 11.41 (a–e) Endocarditis of the mitral valve with prominent granulation tissue attached to the aortic leaflet. The degree of leaflet infiltration can be seen in (b). All infected material must be resected.

Depending upon the amount of remaining tissue, reconstruction with or without pericardial augmentation may be possible

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the problem will vary from valve to valve and many lesions will be concealed by echo drop out pre-operatively. Therefore, these cases should be undertaken by experienced mitral valve surgeons.

References 1. Lillehei CW, Levy MJ, Bonnabeau RC Jr. Mitral valve replacement with preservation of the papillary muscles and chordae tendinae. J Thorac Cardiovasc Surg. 1964;47:532–43.

F. C. Wells 2. Silaschi M, Chaubey S, Aldalati O, et al. Is mitral valve repair superior to mitral valve replacement in elderly patients? Comparison of short- and long-term outcomes in a propensity matched cohort. J Am Heart Assoc. 2016;5:e003605. 3. Carpentier A.  Cardiac valve surgery: “the French correction”. J Thorac Cardiovasc Surg. 1983;86:323–37. 4. McGoon DC. Repair of mitral insufficiency due to ruptured chordae tendineae. J Thorac Cardiovasc Surg. 1960;39:357–62. 5. Alfieri O, et al. The double orifice technique in mitral valve repair: a simple solution for complex problems. J Thorac Cardiovasc Surg. 2001;122(4):674–81.

Surgery of Rheumatic Mitral Valve Disease

12

Francis C. Wells

Rheumatic valve disease resulting from repeated episodes of untreated streptococcus A pharyngitis can present both early and late. Almost one third of cases are asymptomatic and there is no history of such disease in the acute phase resulting in late presentation of mitral stenosis. In the early stage of the disease, there is an acute inflammation of the valve leaflets and often an accompanying myocarditis. Associated with the myocardial inflammation is ventricular dilatation and along with that atrioventricular annular dilatation. Thus, in the acute phase, mitral regurgitation may predominate. In addition, in the acute phase there may be a polyarthritis/ polyarthralgia. This may be accompanied by subcutaneous nodules, erythema marginatum, and choreoathetosis. As the myocardial and leaflet inflammation regresses, it is replaced by fibrosis of the valve leaflets and the sub-valvar apparatus and ventricular myocardial fibrosis. It is in this phase that progressive mitral stenosis will develop. The sub-­ valve apparatus thickens and contracts drawing the leaflets downwards. At the same time the leaflets thicken and retract. The mural leaflet may fuse with the posterior ventricular wall. At surgery, this situation can result in posterior wall ventricular rupture if great care is not taken in mobilising/ removing this leaflet tissue. Children with early-stage rheumatic disease that present with mixed mitral valve disease but predominantly regurgitation can usually be repaired. In the adult population where presentation is late after the acute episodes, repair is still feasible in some cases. This of course is desirable in young women who may wish to have children. Techniques for these scenarios will be described. Patients with severe calcified late presentation rheumatic mitral stenosis will be best treated with mitral valve replacement. Even here, however, it is quite possible to retain most if not all of the sub-valve connections either with the native

F. C. Wells (*) Royal Papworth Hospital, Cambridge University Group of Hospitals, Cambridge, UK e-mail: [email protected]

cords and papillary muscles or the use of Gore-Tex© to form new cords. Dr. Lillehiei reported the importance of the preservation of these connections as early as 1964 [1].

Surgical Techniques  itral Valve Replacement with Sub-Valve M Preservation In more advanced cases where repair is not possible valve replacement, or prosthetic valve insertion, as it is more accurately described, should be done. As in all of cardiac surgery, optimal exposure and control of cardiopulmonary bypass are paramount for success. As in the culinary profession, a variety of “recipes” are available to the surgeon for safe access and myocardial protection but these are my personal preferences. My practice is to use cannulation of the ascending aorta at the distal ascending and aortic arch junction for arterial return and cannulation of both vena cava through the right atrium with the pipes uncrossed. I use a left ventricular vent to assist drainage and snare the cavae with narrow tape “snuggers” to ensure all vena caval return passes through the cannulation pipes and not around them. This ensures fullest drainage and prevents the heart from warming. Gentle elevation of the tapes also helps with exposure of the left atrium and hence the valve. The systemic temperature is lowered to 32 °C, and a continuous irrigation of the pericardium with cold saline at 4 °C is used to lower metabolic rate of the heart and the other organs. The heart is arrested with antegrade cold cardioplegia repeated at 20-min intervals throughout the procedure. The left atrium is usually entered through the atrioventricular groove. A self-retaining retractor is then introduced to expose the valve. A proline stitch through the inferior margin of the incised left atrial wall which incorporates a pump sucker allows better vision.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_12

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a

F. C. Wells

b

Fig. 12.1  Atrial retractor in place and the whole valve easily seen. (a) Barlowe’s valve. (b) Rheumatic mitral stenosis

This set up will give excellent exposure for the vast majority of cases. Properly accomplished each of these moves will optimise the view (Fig. 12.1).

Valve Replacement (Insertion) As a result of the fibrotic distortion of the valve, a strong grip on the valve can be obtained by passing a strong stitch through the body of the aortic leaflet. By pulling this towards the operator, the junction between the leaflet (often very thick and sometimes calcified) and the aorto-mitral curtain can be seen. The leaflet is then incised with an 11-blade knife at the apogee of the leaflet and the incision extended for a centimetre or so in each direction (Fig. 12.2). At this point, the first valve retention stitch is placed at the centre of the incision from the ventricular side. The incision is then extended a further centimetre or so in each direction and further sutures placed. When whole of the aortic leaflet has been mobilised in this fashion, the aortic leaflet is divided in its centre between each of the sets of cords rom each papillary muscle head. The excess leaflet at the apices is resected, and the next sutures are placed through the residual leaflet and then through the annulus pinning the sub-valve apparatus to the underside of the annulus (Fig. 12.3). Next the mural leaflet is detached and divided in its middle between the two sets of cards as with the aortic leaflet. Any excess tissue is resected, and the remainder with the cords attached pinned to the underside of the annulus with the valve sutures. By doing this it can often allow a valve one size bigger than would otherwise be possible. In less fibrotic valves with very little leaflet tissue, the leaflet can just be gathered up in the stitch without detaching it (Figs. 12.4 and 12.5).

Fig. 12.2  The suture in the aortic leaflet is pulling the leaflet down to assist the first incision at the annulus

Valve Orientation With tissue valves it is important to prevent the stent posts from lying in the left ventricular outflow as this can produce a high gradient across the aortic outflow tract. To achieve this, each strut should coincide with the trigones of the mitral annulus.

Annular Decalcification Frequently in more elderly patients with chronic rheumatic mitral stenosis, the annulus and the leaflets calcify, sometimes very extensively (Fig. 12.6).

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Left in situ this dense calcification can make valve insertion extremely difficult. However with some experience and great care it can be excised allowing the insertion of a larger prosthetic valve (Fig. 12.7). Once removed the atrioventricular connection should be re-established with a generous pericardial patch sewn with the lower ventricular margin well below the lower margin of the resection with sutures placed into the pristine ventricular muscle. The upper border is sewn to the atrial wall. There should be no tension on the patch (Fig. 12.8). Once this has been done, the new valve can be sewn into place. Along the mural junction, the sutures can safely be passed through the pericardium.

 itral Valve Reconstruction in Rheumatic M Disease Fig. 12.3  The triangular apices of the detached and divided aortic leaflet are resected

a

Fig. 12.4 (a, b) The sutures passed through the detached mural leaflet

In children and young women, the use of a mechanical valve which would be the valve of choice over a tissue valve in this cohort is to be avoided if at all possible. The reason for this b

F. C. Wells

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Fig. 12.5  The sutures are passed through the valve sewing ring which is then lowered into position and the sutures tied

Fig. 12.7  Showing sharp dissection and removal of an extensive bar of calcium from the annuls. The yellow fat of the atrioventricular junction can be seen

Mural leaflet

Calcified bar

Atrio ventricular fat

Detached mural leaflet Pericardium

Fig. 12.6  Extensive annular calcification of the mitral valve

Fig. 12.8  The mural leaflet has been detached, the calcium removed and the atrioventricular junction restored with a generous pericardial patch

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Fig. 12.9  Insertion of pericardial patch for mural leaflet extension

Mural leaflet detached comm. to comm.

Large native pericardial patch

29 mm

is that long-term warfarin therapy is extremely hazardous in parts of the world where anticoagulant control is poor or non-existent. In the relatively early stage of the disease in children and young adults, reconstruction is often possible. This consists of much more than simple commissurotomy and the division of some restrictive cords. If the aortic leaflet is reasonably well preserved and the majority of the pathology is in and around the mural leaflet and the mural annulus, reconstruction should always be considered. Tethering cords can be divided and/or replaced with Gore-Tex sutures. A heavily retracted mural leaflet can be detached from the annulus and a generous pericardial patch inserted to extend the leaflet length. When done well, this usually results in the leading edge with the cordal attachments becoming the coaptation surface extending down into the ventricular cavity. The patch needs to be quadrangular in shape and not oval and should extend from near commissure to commissure. Similar extension of the aortic leaflet can also be achieved (Fig. 12.9).

Fused and shortened papillary muscle heads can be incised and mobilised. The commissurotomy’s whilst being generous should not extend to the annulus as this is likely to leave new mitral valve regurgitant. In many cases, the leaflets have a fibrotic pannus over the whole of their surface which can with care be peeled away leaving a more flexible leaflet. In all of these cases, stabilisation of the annular orifice is important and to achieve this a simple flexible band extending from Trigone to Trigone excluding the aorto-mitral curtain region is sufficient. The band will be sized on the whole surface area of the tensioned closed mitral valve and not solely upon the anterior leaflet.

Reference 1. Lillehei CW, Levy MJ, Bonnabeau RC Jr. Mitral valve replacement with preservation of papillary muscles and chordae tendinae. J Thorac Cardiovasc Surg. 1964;47:532–43.

Mitral Valve Infective Endocarditis

13

Narain Moorjani

Mitral valve endocarditis represents an infection of one or both mitral valve leaflets. Normal cardiac endothelium is resistant to infection and even with transient bacteraemia, endogenous immune mechanisms, including thrombocidins (microbicidal proteins released by platelets), help to prevent endocarditis. Patients with endothelial disruption or non-­laminar blood flow, such as those with some degree of valve dysfunction (stenosis or regurgitation), however, are at risk of sterile platelet-fibrin thrombus formation. The Venturi effect usually causes the thrombus to form on the low-­pressure side of the turbulent blood flow, such as with mitral regurgitation on the atrial side of the valve. Subsequent bacteraemia allows colonisation of the pre-­ existing thrombus, resulting in vegetation formation. The bacteraemia can be induced by an invasive procedure, such as dental extraction, endoscopy, or surgery in the presence of infection. The organisms are able to multiply within the platelet-fibrin thrombus and are ‘protected’ from the body’s immune system. The most common organisms associated with native valve endocarditis are bacteria, including Streptococcus viridans, Staphylococcus aureus, Staphylococcus epidermidis, and the enterococcus Streptococcus faecalis. Amongst their properties, these organisms are able to induce platelet aggregation, bind to the surface of the fibrin-platelet thrombus, as they possess fibronectin receptors, and resist the bactericidal action of complement and certain platelet proteins.

The pathological effects of infective endocarditis are secondary to spread into the surrounding tissues causing local tissue destruction, such as leaflet perforation or periannular abscess formation. In addition, embolisation of the vegetation can result in peripheral abscesses or infarcts, such as cerebral, renal, or splenic. Peripheral effects of the infective endocarditic process can also occur secondary to immune complex deposition, such as vasculitis or glomerulonephritis.

Echocardiographical Findings Transthoracic echocardiographic images often reveal the presence of a vegetation on the anterior or posterior mitral valve leaflets, associated with normal movement of both the leaflets, on both the apical and parasternal long-­axis views (Fig.  13.1), where the vegetation can be seen as a mobile mass attached to the atrial surface of either leaflet. Doppler flow across the mitral valve may demonstrate a jet of mitral regurgitation (MR), through a perforation in the one of the leaflets (Fig. 13.1). Trans-oesophageal echocardiographic images are often used to confirm the presence of the vegetation on the leaflets and also demonstrate any extension of the infective process into the surrounding structures, such as the mitral valve annulus, aorto-mitral curtain, or aortic valve leaflets (Fig. 13.2).

N. Moorjani (*) Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_13

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Fig. 13.1  Transthoracic echocardiographical images demonstrating a 0.7 cm vegetation lying on the atrial side of the anterior mitral valve leaflet on apical (top left) and parasternal long-axis (top right) views,

N. Moorjani

associated with a jet of severe mitral regurgitation through the perforation on the corresponding parasternal long-axis colour flow Doppler image (bottom)

13  Mitral Valve Infective Endocarditis

Fig. 13.2  Trans-oesophageal echocardiographical images demonstrating a 0.7 cm vegetation on the atrial surface of the anterior mitral valve leaflet on mid-oesophageal long-axis (top left) and 4-chamber (top right) views, associated with a jet of severe mitral regurgitation through

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the perforation on the corresponding colour flow Doppler image (bottom left), and a perforation visible in the body of the anterior leaflet on a 3D short-axis view (bottom right)

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Surgical Strategy

N. Moorjani

mitral valve is assessed, using segmental analysis of the leaflets and the subvalvular apparatus, and correlated with Although a proportion of patients with mitral valve infective the trans-­oesophageal echocardiographical findings. Stay endocarditis can be treated medically with antibiotics, surgi- sutures (5/0 prolene) are placed around the chordae tendincal intervention is often required and should be initiated eae attached on either side of the perforated area of the early to reduce the risk of on-going valve destruction or affected leaflet. Gentle traction on these stay sutures gives embolisation. When operating on these patients, it is impor- better access and visualisation of the leaflet. The vegetatant to first determine whether repair is feasible or replace- tion and any residual infected leaflet surrounding the perment is necessary. Although mitral valve repair in this setting foration are excised and sent for microbiological analysis. may prolong the ischaemia time, there is evidence of both At this stage, it is important to assess the degree of destrucshort- and long-term advantages of repair over replacement, tion to the surrounding tissues and whether enough of the including a lower incidence of recurrent endocarditis, valvular and subvalvular structures remained intact and improved freedom from reoperation, and long-term survival free from the infective process to produce a competent valve by repair. If the valve is deemed repairable, all macadvantage in this patient cohort. roscopically infected and inflamed tissue is excised to ensure that the residual native tissue is free from infection, with a 2  mm margin. The residual tissue must be strong Indications for Surgery enough to hold suture material. Repair of a defect in the anterior leaflet is usually possi 1. Uncontrollable sepsis despite appropriate antibiotics for ble, even if up to 50% of the leaflet body is involved, so long as the leading edge of the anterior leaflet, along the coaptaan adequate time (7 days) tion line, is intact. The defect in the leaflet body may be 2. Abscess formation in the annulus or leaflets repaired with fresh autologous pericardium, glutaraldehyde-­ 3. Uncontrollable heart failure 4. Significant embolisation from large vegetations on the treated autologous pericardium, or bovine pericardium. Bovine pericardium is used if autologous pericardium is not leading edge of the leaflets 5. Any of the above in association with Staphylococcus available, such as in patients undergoing reoperation. Bovine pericardium, as well as glutaraldehyde-treated autologous aureus infection pericardium, also has the advantage of being easier to handle The timing of surgery needs to be carefully considered, and are used for more complex reconstructions. Although especially as early surgery in the presence of significant on-­ decellularised porcine intestinal submucosa (CorMatrix™) going infection runs the risk of recurrence of infection, par- has also been used for leaflet patch augmentation, there have been reports of patch dehiscence or tearing using this ticularly in the presence of an artificial valve. During the operation, it is important to avoid excessive material. The pericardium is implanted using a continuous locking manipulation of the heart before the aortic cross-clamp has been applied, to avoid systemic embolisation of infected tis- 5/0 prolene suture, to avoid purse-stringing the patch sue. The key principle in determining the feasibility of valve (Figs. 13.3 and 13.4). It is important to oversize the patch to repair in patients with mitral valve infective endocarditis is ensure that there is no tension on the leaflet causing restricted to identify the lesions caused by the infective process and the leaflet motion. In some patients, additional Gore-Tex neo-­ extent of tissue destruction. There are several patterns of chordae are required to support the free edge of the anterior destruction encountered in these patients, including perfora- leaflet. Infective lesions of the posterior leaflet can usually be tion of the anterior leaflet, destruction of the posterior leaflet, commissural prolapse, and annular abscess. It is quite com- treated by resection, using the standard principles of trianmon to find anterior leaflet perforation in patients with con- gular or quadrangular resection, with or without annular comitant endocarditis of the aortic valve, due to jet lesions plication and sliding plasty. In addition, some patients will require patch augmentation or Gore-Tex neo-chordae to onto the aorto-mitral curtain and anterior leaflet. support the leaflet body and free edge, respectively (Fig. 13.5). Infective destruction of the anterolateral or posteromedial  eaflet Reconstruction L commissure, however, can be more difficult to treat. In patients where the regurgitation is caused by leaflet per- Following resection of the infected adjacent segments, slidforation, it is important to assess whether it is possible to ing plasty is often required to advance posterior leaflet tissue resect the infected tissue with a clear margin, whilst leav- to reconstruct the commissure (Fig. 13.6). Again additional ing enough native tissue to form a competent valve. The patch augmentation, Gore-Tex neo-chordae or annular plica-

13  Mitral Valve Infective Endocarditis Fig. 13.3 (a) Perforation of the anterior mitral valve leaflet caused by the presence of a vegetation and infective destruction of the native tissue, and (b) repair with bovine pericardium patch augmentation of the anterior leaflet and ring annuloplasty

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a

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Fig. 13.4  Operative images illustrating (a) 0.7 cm vegetation lying on the atrial surface A3 scallop of the anterior leaflet, (b) resected vegetation and surrounding infected tissue, (c) closure of the defect in the A3

segment of the leaflet with a bovine pericardial patch, and (d) implantation of an annuloplasty ring to support the repair

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a

b

Fig. 13.5 (a) Perforation of the posterior leaflet caused by the presence of a vegetation and infective destruction of the native tissue, and (b) repair with bovine pericardium patch augmentation of the posterior leaflet and ring annuloplasty Fig. 13.6 (a) Prolapse of the posteromedial commissure caused by the presence of a vegetation and infective destruction of the underlying native tissue, (b) debridement of the infected tissue, (c) repair with sliding plasty advancement of the medial half of the posterior leaflet and commissuroplasty, and (d) ring annuloplasty to support the repair

a

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tion may also be required to support the commissural reconstruction. The vegetation and any resected tissue should be sent for microbiological analysis. Any underlying mitral valve pathology, which may have contributed to the development of the infective endocarditis, should also be treated during the repair procedure using standard techniques. Degenerative mitral valve prolapse is the most common underlying cardiac

lesion that predisposes to mitral valve infective endocarditis. Once the repair procedure has been completed, it is important to stabilise the mitral valve annulus with an annuloplasty band or ring, thereby relieving the tension on the leaflets by optimising the coaptation zone. Although some advocate avoidance of using prosthetic material in these patients, there is no evidence that using an annuloplasty ring

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or band increases the risk of recurrent endocarditis but it does increase the longevity of the repair. Following implantation of the annuloplasty ring or band, injecting cold saline allows the mitral valve to be assessed for competency, adequate depth of coaptation (>8 mm) and that the coaptation line runs parallel to the posterior annulus.

Annular Reconstruction In patients with infective endocarditis of the mitral valve, it is important to explore the surrounding tissues to assess for the presence of any peri-annular abscess or spread onto the aorto-mitral curtain. If present, extension of the infective process into the posterior annulus with resulting peri-annular abscess formation will require extensive debridement of the Fig. 13.7 (a) Abscess of the posterior mitral valve annulus, (b) debridement of infected tissue extending into the atrioventricular groove, (c) bovine pericardium patch reconstruction of the atrioventricular groove, extending onto the posterior wall of the left ventricle and left atrium, (d) bovine pericardium patch reconstruction of the posterior leaflet, and (e) ring annuloplasty to support the repair

annulus and the abscess cavity, followed by reconstruction of the posterior annulus and atrioventricular groove (Fig. 13.7). An oversized fresh autologous or bovine pericardial patch is used to cover the defect in the atrioventricular groove and attached to the adjacent posterior walls of the left ventricle and left atrium using a continuous 4/0 prolene suture. It is important to place the sutures in the ventricle distant from the edges of the resected material to ensure a strong suture line. Left atrial and ventricular pressures help to maintain apposition of the patch against the posterior wall of the heart. The reconstructed posterior annulus with pericardial patch can then be used to receive the interrupted valve annuloplasty or replacement sutures, which will additionally help to secure the patch in situ. If repair is not possible and replacement is necessary, the choice between a mechanical or biological valve should be

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made with the usual considerations, as there is no difference in recurrent endocarditis rates between the two valve choices. Following all surgery for mitral valve endocarditis (repair or replacement), organism-specific intravenous antibiotics should be continued as dictated by current international recommendations, usually for 4–6  weeks. If organisms are grown from the resected material, it is the authors recommendation that antibiotic treatment should continue for 6  weeks with a full endocarditis screen 2 weeks after the completion of the treatment.

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carditis, and reduced need for a reoperation in patients undergoing repair. The increased incidence of reoperation in patients undergoing replacement for mitral valve endocarditis is related to paravalvular leaks, structural valve deterioration, and prosthetic valve endocarditis.

Suggested Reading

AATS Surgical Treatment of Infective Endocarditis Consensus Guidelines Writing Committee Chairs, Pettersson GB, Coselli JS, Writing Committee, Pettersson GB, Coselli JS, Hussain ST, Griffin B, Blackstone EH, Gordon SM, LeMaire SA, Woc-Colburn LE. The 2016 the American Association for Thoracic Surgery (AATS) conSurgical Tips sensus guidelines: surgical treatment of infective endocarditis. J 1. Complete debridement of the vegetation and adjaThorac Cardiovasc Surg. 2017;153(6):1241–58. de Kerchove L, Price J, Tamer S, Glineur D, Momeni M, Noirhomme cent infected and inflamed tissue is necessary to P, ElKhoury G. Extending the scope of mitral valve repair in active reduce the risk of recurrence. endocarditis. J Thorac Cardiovasc Surg. 2012;123(4 Suppl):S91–5. 2. Assess that there is enough residual tissue after Evans CF, Gammie JS. Surgical management of mitral valve infective resection to allow for repair. endocarditis. Semin Thorac Cardiovasc Surg. 2011;23(3):232–40. Harky A, Hof A, Garner M, Froghi S, Bashir M.  Mitral valve repair 3. Augment any defects in the leaflet tissue or annulus or replacement in native valve endocarditis? Systematic review and with bovine or autologous pericardium. meta-analysis. J Card Surg. 2018;33(7):364–71. 4. Support the leaflet repair procedure with an annuloKitai T, Masumoto A, Okada T, Koyama T, Furukawa Y. Optimal timing plasty ring or band. of surgery for patients with active infective endocarditis. Cardiol Clin. 2021;39(2):197–209. Okada Y, Nakai T, Kitai T. Role of mitral valve repair for mitral infective endocarditis. Cardiol Clin. 2021;39(2):189–96. Otto CM, Nishimura RA, Bonow RO, Carabello BA, Erwin JP 3rd, Gentile F, Jneid H, Krieger EV, Mack M, McLeod C, O'Gara PT, Comment Rigolin VH, Sundt TM 3rd, Thompson A, Toly C. 2020 ACC/ AHA guideline for the management of patients with valvular heart For endocarditis patients who have limited valve destruction, disease: executive summary: a report of the American College the results of mitral valve repair have shown excellent outof Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation. 2021;143(5):e35–71. comes, with an in-hospital mortality of 3% and a low peri-­ Sareyyupoglu B, Schaff HV, Suri RM, Connolly HM, Daly RC, Orszulak operative complication rate. In general, however, patients TA. Safety and durability of mitral valve repair for anterior leaflet with acute mitral valve endocarditis have an operative morperforation. J Thorac Cardiovasc Surg. 2010;139(6):1288–93. tality of 10–20%. Long-term outcome measures at 10 years Shimokawa T, Kasegawa H, Matsuyama S, Seki H, Manabe S, Fukui T, Morita S, Takanashi S. Long-term outcome of mitral valve repair for of patients who have undergone repair have also demoninfective endocarditis. Ann Thorac Surg. 2009;88(3):733–9. strated excellent freedom from recurrent mitral regurgitation Toyoda N, Itagaki S, Egorova NN, Tannous H, Anyanwu AC, (91% with no or 1+ MR), freedom from reoperation (91%), El-Eshmawi A, Adams DH, Chikwe J. Real-world outcomes of surand survival (80%). Meta-analyses and large series compargery for native mitral valve endocarditis. J Thorac Cardiovasc Surg. 2017;154(6):1906–12. ing repair versus replacement in patients with mitral valve Zegdi R, Debièche M, Latrémouille C, Lebied D, Chardigny C, Grinda infective endocarditis have shown better short- and long-­ JM, Chauvaud S, Deloche A, Carpentier A, Fabiani JN. Long-term term outcome measures, with a lower operative mortality, results of mitral valve repair in active endocarditis. Circulation. increased long-term survival, reduced risk of recurrent endo2005;111(19):2532–6.

Part IV Valve Surgery: Tricuspid Valve Surgery

Tricuspid Valve Disease Techniques

14

Narain Moorjani, Francis C. Wells, and Samer A. M. Nashef

As the name suggests the right-sided atrioventricular valve has three primary leaflets, the anterior, septal, and inferior leaflets. Other than that, the same basic components of papillary muscles and tendinous cords are present. The overall shape is more a rounded triangle than the oval mitral valve orifice. This shape required the development of the third, inferior, leaflet which may represent an enlarged commissural leaflet. The largest leaflet is the anterior leaflet, the third being the septal leaflet (Fig. 14.1). The relationships of the leaflets to the supporting cardiac chamber muscle are as follows and shown in Fig. 14.1. The origin of the anterior leaflet is at the septal junction with the aortic root and extends along the majority of the right ventricular muscular free wall. This is an important point as it is this portion of the atrioventricular junction that stretches giving rise to type 1 annular dilatation and is the cause of secondary tricuspid regurgitation. As the right ventricle dilates progressively with volume and pressure overload, this dilatation causes distraction of the tricuspid valve leaflets from their natural coaptation lines. Correction of the valve incompetence is achieved by reducing this part of the circumference of the orifice. The inferior leaflet is associated with the remainder of the right ventricular wall and its junction with the septum, and is of variable length. As in functional (secondary) mitral regurgitation, in tricuspid regurgitation there is no visible stretching of the septal portion nor of the aortic outflow area.

N. Moorjani Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK F. C. Wells (*) Royal Papworth Hospital, Cambridge University Group of Hospitals, Cambridge, UK e-mail: [email protected] S. A. M. Nashef Department of Surgery, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected]

In the normal tricuspid valve, the plane of the valve in relation to the atrioventricular junction is complicated with more deviation from the neutral plane than is found in the mitral valve (see Fig. 14.1). Of how much this is of importance to the normal function of the valve is debatable. Although some of the industry offer rigid annuloplasty rings that pay homage to this differential planar, it is no more than a gesture as they only adjust in one direction. The only annuloplasty support that more closely allows approximation to the natural shape is one that is flexible for the whole of the right ventricular line of attachment. Whilst some would argue that the draw string approach of the De Vega procedure will allow for this, the suture is usually pulled so tight, to reduce the orifice size, as to become relatively stiff. The role of any annuloplasty ring is to reduce the orifice size to bring the leaflets back into coaptation and to stabilize the base of the right ventricle. Allowing motion of the annulus throughout the cardiac cycle may be an added benefit though none has been shown. The most common cause of tricuspid regurgitation is atrial and ventricular dilatation, usually as a result of chronic atrial fibrillation. Whilst this statement is true, it is always important to look out for loss of sub-valvar integrity through cordal or papillary muscle elongation, rupture, or congenital absence. In Barlow’s disease, the changes that are seen in the mitral valve are frequently found in the tricuspid valve. Although as a result of the lower pressures on the right side, the excess tissue seen in this condition prevents early regurgitation, it can be seen in patients that present late with raised pulmonary artery pressures and RV dilatation. In this situation, an annuloplasty ring will usually suffice. Causes of cordal and papillary muscle rupture include endocarditis (particularly with Staphylococcus), trauma (both blunt and sharp forms), and occasionally catheter trauma from malpositioned Swan-Gantz catheters and pacing wires. Sudden and massive deceleration against the closed valve in systole can cause rupture as in road traffic accidents or falls from a height. Knife wounds are another cause and should be thought of in penetrating chest injury.

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_14

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Anteroseptal commissure

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b Anterior leaflet Posterior leaflet Septal leafleft

Membranous septum

AV node

Posteroseptal commissure Coronary sinus

c Control RA high

Functional TR RA High

Ao valve

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Low RV apex Low RV apex Fig. 14.1 (a) The functional anatomy of the tricuspid valve. (b) The site of annular dilatation of the valve orifice. (c) The planar shape of the tricuspid annulus in the normal and the dilated state

Much greater attention has been given to both primary and secondary Tricuspid regurgitation (TR) of late, and the morbidity and mortality from untreated TR have been reported more widely in recent years [1]. The traditional acceptance of the lesion as a bystander lesion, not needing attention, has been consigned to the dustbin of cardiac surgical history. Something less spoken of however is the production of tricuspid stenosis from too great a reduction of orifice circumference and hence orifice area brought about by an assumption that the greater the degree of coaptation the longer lasting the result. In choosing the appropriate ring size, it should at least approximate to the size of the fully developed anterior leaflet.

The ‘de Vega’ technique of suture annuloplasty has been shown to have inferior results in most hands and is rarely used in the modern era [2]. The development of worsening TR post left-sided valve surgery is accompanied by worse long-term results. There is a higher morbidity and mortality when tricuspid regurgitation is corrected at a second operation, hence restoration of competency at the first operation for mitral valve disease is to be recommended if the orifice is dilated significantly, with an orifice diameter in the diagonal plane of greater than 4.0 cm and there is more than mild regurgitation. A tabular schema for the management of tricuspid regurgitation is shown in Fig. 14.2 [3].

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14  Tricuspid Valve Disease Techniques FTR disease processes Left-sided heart disease

Atrial fibrillation

Right ventricular (RV) afterload increase (with or without pulmonary hypertension)

RV remodeling

Altered RV function

Tricuspid annular dilation. (In some instances leaflet tethering occurs with the same triggering factors)

Abnormalities of tricuspid anatomy and function lead to functional tricuspid regurgitation (FTR)

FTR assessments

Diagnosis and treatment

Tricuspid regurgitation (TR) TR is the leakage of blood backwards through the tricuspid valve each time the right ventricle contracts Color flow jet visualization is used to evaluate PISA radius and effective regurgitant orifice or regurgitant volume Annular dilation The annular ring is attached to the tricuspid valve leaflets. Dilation can result in poor leaflet apposition 2D-echocardiography coupled with 3D imaging is used to accurately measure annular diameter Leaflet coaptation mode Coaptation is the surface where the leaflets meet. If decreased, contact is made at the leaflet edge (edge-toedge), leaflet tethering can restrict leaflet closure 3D echocardiography is recommended to measure tenting volume (TV) the area within the tricuspid leaflets

Stage 1

Stage 2

Stage 3

TR severity: None or mild

TR severity: Mild or moderate

TR severity: Severe

Annular diameter: 40 mm

Annular diameter: >40 mm

Coaptation mode: Normal (body-to-body), with no leaflet tethering

Coaptation mode: Abnormal (edge-to-edge), with or without tethering of 8 mm below the annular plane

Medical treatment. No surgical Intervention is indicated

Concomitant tricuspid valve annuloplasty is recommended

Concomitant tricuspid valve annuloplasty and leaflet augmentation (if tethering is present)

Fig. 14.2  Tabular classification of tricuspid regurgitation. (From Dreyfus et al. [4]; with permission)

Insertion of Annuloplasty Band In placing the annuloplasty ring, suture care must be taken at two sites in particular. The first is in the region of the atrioventricular node and bundle and the second in the region of the right coronary artery. Too deep placement in both areas

may cause problems. In the A-V nodal area, that of heart block and in the region of the right coronary artery, coronary distortion and occlusion can occur to devastating effect [4]. It is most important the needle is directed down into ventricular muscle and not tangentially into the surrounding atrial tissues (Fig. 14.3).

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Through hinge

2mm from hinge

Backhand Forehand

and Foreh nd

a ckh Ba

2mm from hinge

Aortic segment

Through hinge

Fig. 14.3  Suture techniques for tricuspid annuloplasty

De Vega Technique The de Vega annuloplasty is a simple suture technique with which to narrow down the annulus of the tricuspid valve. Although it was the most common procedure to correct TR, it has largely fallen out of favour because of evidence of higher rates of recurrent tricuspid regurgitation, largely due to sutures cutting out of the flimsy tricuspid ‘annulus’, resulting in the return of annular enlargement and the ‘guitar string sign’ of sutures crossing the orifice. This can be avoided by a slight modification of the technique: the first suture is taken inferiorly at the septal-posterior leaflet commissure, with the second suture going back on itself to start at the midpoint of the first suture (Figs. 14.4 and 14.5). This is continued until the point where conduction tissue begins (X in the figure), then the course of the suture is reversed to anticlockwise and the suture line is completed in the same way back to the starting point. This results in a double line of cinching sutures that simply cannot cut out. In the overwhelming majority of cases, the annulus can be reduced to the desired diameter with two sutures lines as above. Where the annulus is enlarged to an exceptional degree, a third or even a fourth suture line may be needed. As mentioned earlier this was the mainstay of management of tricuspid annular dilatation. Several recent papers

Fig. 14.4  Classical de Vega suture technique

have shown the relative inferiority of this technique over ring annuloplasty, but the double row of suturing technique as shown here seems to be more stable over long follow-up periods. The important points to stress with this modification are as follows. First the suture line must start and finish at the same end points as they would for an annuloplasty ring, and secondly, a two-layer approach as shown should be used rather than the single traditional layer.

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a

c

Fig. 14.5  Modified de Vega technique

The Clover Leaf Stitch In this technique, the central coaptation point of each leaflet is sewn together giving a central point of fixation, analogous to the Alfieri edge-to-edge technique in the mitral valve (Fig. 14.6). Fig. 14.6 (a–c) Clover stitch

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Inferior Leaflet Imbrication Stitch Here the inferior leaflet is excluded with robust sutures through the annulus at either end of the leaflet which when

Fig. 14.7  Inferior leaflet imbrication. Here the inferior leaflet is excluded with robust sutures through the annulus at either end of the leaflet which when tied excludes the leaflet and that part of the orifice from the inflow of the valve

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tied excludes the leaflet and that part of the orifice from the inflow of the valve (Fig. 14.7).

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 nterior Leaflet Augmentation A with Pericardium In this technique, a generous patch of pericardium is sewn onto the detached annular portion of the anterior leaflet. It is important to use a patch at least one third bigger than the

Fig. 14.8  Anterior leaflet augmentation with pericardium

defect when stretched open to allow for shrinkage of the pericardium with the passage of time. It also gives a generous height of coaptation to the leaflets. An annuloplasty partial band is then placed in the usual way (Fig. 14.8).

Line of incision

AL PL SL

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Sub Valve Repair Techniques

References

As with the mitral valve occasionally, there are cordal ruptures and papillary muscle avulsions in the tricuspid valve. These can be addressed in the same way as in the mitral valve with the insertion of neo-cords, usually with Gore-Tex sutures. This is commonly the situation encountered in trauma cases reconstruction is desirable, as valve replacement on the right side is usually relatively short lived with early valve failure (Fig. 14.9).

1. Naja I, et al. Traumatic tricuspid regurgitation. J Cardiovasc Surg. 1992;33:256. 2. Maisano F, Lorusso R, et  al. Valve repair for traumatic tricuspid regurgitation. Eur J Cardiothorac Surg. 1996;10:867–73. 3. Dreyfus GD, Martin RP, Chan KM, Dulguerov F, Alexandrescu C.  Functional tricuspid regurgitation: a need to revise our understanding. J Am Coll Cardiol. 2015;65(21):2331–6. 4. Tornos Mas P, Rodriguez-Palomares JF, Antunes M.  Secondary tricuspid valve regurgitation: a forgotten entity. Heart. 2015;101:1840–8.

Suggested Reading Tang GHL, David T, Singh S, et al. Tricuspid valve repair with an annuloplasty ring results in improved long-term results. Circulation. 2006;114:I577–81. Tsuchida K, et  al. Right coronary artery stenosis associated with tricuspid valve ring annuloplasty. Cardiovasc Interv Ther. 2017;32(4):420–4. 1

2

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Fig. 14.9  Sub valve repair techniques (1 through 5)

Tricuspid Valve Replacement

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Narain Moorjani

In patients with extensive disease of the tricuspid valve where repair is not feasible, such as marked leaflet tethering, retraction or calcification with rheumatic valve disease (Fig. 15.1a), or carcinoid, replacement of the valve is indicated. The choice between a mechanical or biological stented valve remains controversial. Although both have similar outcomes for survival, mechanical valves are prone to thromboembolic complications in the low-pressure right-sided circulation. Although mechanical valves are thought to have a greater durability, there is evidence of good long-term durability of a tricuspid valve bioprosthesis in the low-­ pressure right-sided circulation, even in relatively young patients. Interrupted pledgeted non-everting 2/0 Ethibond sutures are placed along the annulus, from the right ventricle into the right atrium, with approximately 8–10  mm between each limb of the suture and 1  mm spacing between adjacent sutures (Fig. 15.1b). It is important to place the sutures vertically into the myocardium and not horizontally into the atrial or septal tissue. The depth of suture placement needs to be sufficient so that the suture does not tear through. Knowledge

of the anatomical position of nearby structures, such as the right coronary artery, aortic valve, conduction tissue or coronary sinus is essential. At the superomedial aspect of the septal annulus, sutures are placed through plicated septal leaflet tissue to avoid the conducting tissue, which lies at the apex of the triangle of Koch. The valve orifice is then measured, using the sizers provided by the manufacturers. The sutures are placed through the sewing ring, and the prosthesis is the tied down. When tying down the sutures for a stented biological valve, it is important to ensure that the sutures do not get trapped around the stents of the prosthesis. Certain bioprostheses come with a guard to reduce the risk of this occurring (Fig. 15.1c). A bioprosthetic tricuspid valve is orientated with the stents aligned with the anteroseptal and the posteroseptal commissures (Fig. 15.1d). A mechanical prosthesis is orientated in an anti-anatomical position, so that the maximum flow is directed into the right ventricular outflow tract. Prior to closure of the right atriotomy, it is important to ensure both mechanical and tissue leaflets of the prosthesis open and close properly.

N. Moorjani (*) Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_15

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Fig. 15.1  Operative images demonstrating a tricuspid valve replacement, with (a) a rheumatic tricuspid valve characterised by fibrotic, retracted leaflets, and rolled up free edges, (b) implantation of the valve replacement sutures, using a non-inverting horizontal mattress 2/0

Ethibond sutures, plicating any residual leaflet tissue; (c) parachuting of the prosthetic valve down to annulus, with the protective guard in situ to prevent the sutures getting caught around the struts; (d) tricuspid valve bioprosthesis in situ, following tying down of the sutures

Suggested Reading

Dreyfus J, Dreyfus GD, Taramasso M. Tricuspid valve replacement: the old and the new. Prog Cardiovasc Dis. 2022;72:102–13. Hwang HY, Kim KH, Kim KB, Ahn H.  Propensity score matching analysis of mechanical versus bioprosthetic tricuspid valve replacements. Ann Thorac Surg. 2014;97:1294–9.

Anselmi A, Ruggieri VG, Harmouche M, Flécher E, Corbineau H, Langanay T, Lelong B, Verhoye JP, Leguerrier A. Appraisal of longterm outcomes of tricuspid valve replacement in the current perspective. Ann Thorac Surg. 2016;101:863–71.

Part V Surgery of the Aorta

Aortic Arch and Ascending Aorta Replacement

16

Ravi J. de Silva

The development of aortic arch surgery credits many of the doyens in our relatively young surgical speciality. In 1957, Michael DeBakey described the first aortic arch replacement. The use of deep hypothermia and circulatory arrest to facilitate arch surgery was pioneered by Griepp in the 1970s, and then Hans Borst of Hanover introduced the elephant trunk into our surgical lexicon. This involves leaving a free-­floating vascular graft in the patient’s native descending aorta at the time of arch replacement. The technique was further modified by Crawford and Svensson in the 1990s and has since been superceded by the frozen elephant trunk, which replaces the free-floating vascular graft with a covered stent deployed into the descending aorta. At Papworth, we have the largest experience of frozen elephant trunk (FET) arch replacement in the UK.  Terumo Aortic and Artivion each produce a FET device (Fig.  16.1), either of which can be used in the technique we describe. Despite advances in medical technology and surgical techniques, the aortic arch remains a relatively hostile surgical environment. Vital adjacent neurovascular structures invite complications such as stroke, limb ischaemia, recurrently laryngeal nerve palsy, mesenteric ischaemia, and paraplegia. The technique described below aims to minimise the risk of these potentially devastating complications.

Replacement of the ascending aorta often accompanies replacement of the aortic arch, although the reverse is less so. Contributions of Denton Cooley to the field of aortic surgery cannot be over stated. He was the first to report replacement of the ascending aorta using a homograft in 1956, and his subsequent endeavours lead to creation of the prosthetic vascular grafts we use today. Guidelines for the surgical management of the ascending and arch of aorta are published and periodically revised in Europe and North America (EACTS and AATS, respectively). Briefly, a maximum diameter of more than 55 mm or a rapid increase in size (>1 cm in 6 months) in patients without connective tissue disorders is an indication for elective surgery. For patients with connective tissue disease, the aorta may warrant surgery at smaller dimensions depending on the natural history of the disease. Emergency surgery may also be indicated in acute aortic syndromes and trauma, and is also detailed extensively in the previously mentioned publications. We find a multidisciplinary approach with cardiologists, vascular surgeons, interventional radiologists, and cardiac surgeons is essential when deciding the appropriate management of these complex patients.

R. J. de Silva (*) Department of Surgery, Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_16

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118 Fig. 16.1  An example of a frozen elephant trunk device. (a) The proximal graft section with the 3 arch branches and the lower body perfusion branch. This comes attached to a covered stent section. (b) The device in situ

R. J. de Silva

a

Replacement of the Aortic Arch Preparation of the patient begins in the anaesthetic room, where in addition to standard cardiac set-up, the patient must have arterial pressure lines in both radial arteries and a suitable femoral vessel. In cases of aortic dissection, it is preferable to choose the femoral artery which is ideally not dissected from which to transduce pressure. In addition, the patient has a urinary catheter equipped with a temperature probe to measure core temperature (in addition to the nasopharyngeal temperature probe), and a method of monitoring of cerebral perfusion. For this, we currently use near infrared spectroscopy (NIRS), taking care not to drop below baseline readings throughout the procedure. We use cerebrospinal fluid drains in cases of chronic aortic dissections when spinal perfusion may be vulnerable. A Swan-Ganz catheter is placed for cardiac output monitoring which is important post operatively. The cardiopulmonary bypass machine is also configured differently with two arterial return lines each with a flow probe, so differential flows can be achieved. In these protracted procedures, we prefer to use a centrifugal pump. Triangulation of communication between surgical, anaesthetic, and perfusion staff must be constant, clear, and concise throughout the operation. Arterial return for the bypass machine is initially through both axillary arteries. These are exposed in the deltopectoral groove through a 5 cm incision and subsequent division of the pectoralis muscles (Fig. 16.2). The fat pad overlying the axillary artery is resected using a combination of cautery and sharp dissection, taking great care not to damage the brachial

b

plexus. A large cord of this plexus is reliably found overlying the axillary artery and is gently retracted to give adequate exposure. After 5000 units of heparin is administered intravenously, the axillary artery is clamped using a Cooley clamp, a linear incision is made over the clamped section of artery and extended to 1  cm in length. A 10  mm diameter vascular graft is then anastomosed to this in an end-to-side fashion using 5/0 prolene (Fig. 16.3). The graft to the right axillary artery can be short (10 cm), but to the left artery it should be at least 20  cm in length for reasons that will become clear in due course. We use a 3/8 inch connector join the vascular grafts to the arterial return lines, and then proceed to median sternotomy and central venous cannulation after full systemic heparinisation. The heart is vented through a cannula placed in the left ventricle via the right superior pulmonary vent, and a ‘Y’ cannula in the proximal ascending aorta. The pericardial field is flooded with carbon dioxide and once on full cardiopulmonary bypass using both arterial return lines, the patient is cooled to a nadir of 25 °C on the bladder temperature probe. During this time, if additional cardiac procedures (e.g. valve surgery, coronary revascularization) are required, they are completed whilst cooling down using cold blood cardioplegia for myocardial protection. If not, invariably between 27 and 30 °C, the heart will begin to fibrillate. At this point, a cross clamp is placed just distal to the vent in the ascending aorta, with the handle of the clamp pointing to the feet of the patient. The vent is then perfused with warm blood at a physiological pressure (between 60 and 70 mmHg), as transduced through a green hub needle placed in the aortic root. This should produce a normal cardiac rhythm with no signs of ischaemia on the

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16  Aortic Arch and Ascending Aorta Replacement Fig. 16.2  The axillary artery is found deep to the deltopectoral groove

Pectoralis minor

Cephalic vein

Clavipectoral fascia Pectoralis major

Axillary artery Subclavius muscle Thoracoacromial artery

Posterior cord

Lateral pectoral nerve

Medial pectoral nerve Axillary vein

Lateral cord

Pectoralis minor

Clavipectoral fascia

Fig. 16.3  10  mm vascular graft anastomosed to the axillary artery using a 5/0 prolene suture

ECG. However in some instances this proves elusive and we switch from warm blood perfusion to cold blood cardioplegia, which is repeated at 20 min intervals. Whilst waiting for the patient to cool, dissection of the arch vessels is carried out. Nylon tapes are placed around the innominate and left carotid vessels. The left subclavian artery is usually the least accessible, and in many aortic pathologies can be fragile. We encircle this with two silk ligatures at its base. With the patient core temperature at 25 °C, the operating table is moved to a steep Trendelenburg position. Before this, an appropriate myocardial protection strategy (continuous

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warm blood perfusion or intermittent cold blood cardioplegia) must be established. The flow in the bypass machine is dropped and clamps applied as distally as possible to the innominate and left carotid arteries. The silk ligatures around the proximal left subclavian artery are then tied, and the bypass flow resumed and titrated to maintain the NIRS reading above baseline. This is usually around 10  mL/kg/min, divided equally down both arterial lines, but it is vital both anaesthetist and perfusionist remain vigilant of the NIRS and alter flow accordingly. The surgeon will be concentrating on reconstructing the arch. At this point, the lower body is ischaemic and so it is imperative the surgeon works meticulously and efficiently. The aorta is transected at the appropriate zone. We deploy most of our FETs in aortic zone zero or one, which means one or both of the first two branches of the arch are cut where they take off from the aorta and the defect on the aorta repaired with multiple pledgeted 4/0 prolene sutures. A cardiotomy sucker is placed in the distal aorta to scavenge any collateral flow that will otherwise obscure the surgical field. A pledgeted 3/0 prolene suture is placed at 2 o’clock, 6 o’clock and 10 o’clock on the distal aorta, with pledgets lying on the outside of the native aorta. These are hung on rubber-shod mosquito clips. A suitably sized FET is then deployed into the aorta. In cases of aortic dissection, this is done over a guidewire that has been introduced via the cannulated femoral vessel, and visualised to be in the true lumen of the thoracic aorta on TOE prior to transection of the aorta. The 3/0 prolene sutures are used to anchor the collar of the FET to the distal aorta, and then used to create a semicontinuous haemostatic suture line. We usually complete the posterior part of the anastomosis first, going from 2 to 6 o’clock. Once this suture line is completed, the flow through the left axillary line is stopped and the graft clamped. The left arterial return line is then separated from the graft and connected to the lower body perfusion arm of the FET. Flow is restarted down this arterial line, thus ending lower body ischaemia. At 25 °C, this can safely extend to 40–50 min, but invariably in our practice it is less than 30 min. We aim for lower body perfusion to produce a femoral artery pressure of between 50 and 60 mmHg. Attention is then turned to the left carotid artery which is anastomosed to the second branch of the FET graft using 5/0 prolene with a continuous suture line. Once the left carotid is reperfused, patient rewarming can commence whilst the graft anastomosed to the left axillary artery is delivered into the mediastinum through the second intercostal space. Great care is taken not to kink the graft. This graft is shortened to the appropriate length and anastomosed to the third branch of the FET graft using 4/0 prolene, then first branch of the FET is then anastomosed to the innominate artery using 5/0 prolene. By this point all of the arch branches are being perfused via the lower body perfusion line, and so flow into the

R. J. de Silva

Fig. 16.4  The completed arch replacement showing the arch anastomoses (a extra-anatomical left subclavian anastomosis; b left carotid artery; c innominate artery)

right axillary artery can be stopped. The proximal graft to aorta anastomosis is done using a single 4/0 prolene and may require cardioplegic arrest of the heart and release of the proximal cross-clamp to facilitate a perfect anastomosis (Fig. 16.4). After rewarming the patient fully, weaning from bypass can commence in routine fashion. The graft to the right axillary artery is transected short (1  cm) and oversewn with a double layer of 4/0 prolene. The axillary artery wounds are closed taking great care not to disrupt any of the branches of the brachial plexus. Our technique using bilateral axillary artery cannulation reduces the technical complexity of completing the left subclavian anastomosis in the traditional way, which is often the most inaccessible and difficult of the anastomoses. Less manipulation around the subclavian artery also reduces the incidence of recurrent laryngeal nerve injury which we have not seen in our practice for many years. Perfusion through the left axillary line also augments bilateral cerebral and spinal perfusion that would otherwise rely on collaterals from the right carotid and vertebral arteries.

Replacement of the Ascending Aorta This is approached through a median sternotomy or ministernotomy down to the third intercostal space with transection of the right hemisternum to aid exposure. Central cannulation for cardiopulmonary bypass is established, and a vent is placed in the left ventricle through the right superior pulmonary vein. Aortic cannulation may need to be mid arch or of the innominate artery depending on the extent of the aneurysm. If the right atrium is inaccessible through a ministernotomy, percutaneous cannulation of the right femoral

16  Aortic Arch and Ascending Aorta Replacement

vein over a guidewire is performed, or cannulation of the superior vena cava using a three-stage cannula achieves excellent venous drainage. The patient is cooled to 32  °C, and the pericardial field flooded with CO2. Cold blood cardioplegia is delivered intermittently both ante- and retro-gradely. The diseased aorta is excised taking great care not to damage the right pulmonary artery which is frequently adherent to the back of the aorta. In this eventuality, repair of a damaged pulmonary artery is best done using a pericardial patch rather than direct approximation. A suitably sized vascular graft is chosen and cut to an appropriate length. A 4/0 prolene suture is used to construct the proximal and distal anastomoses. The needle is mounted forehand, and suturing of the proximal anastomosis begins at 4 o’clock on the graft, passing the needle from outside to inside. The suture length is equalised, and the distal end pinned to the drapes using a rubber-shod. Suturing continues with the needle mounted forehand, passing from native aorta to graft, until about 10 o’clock. The other needle is then used to complete the anas-

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tomosis using a forehand suture technique throughout. The distal aortic suture line is constructed in a similar fashion, but starting with the needle passing outside to inside of the native aorta. As this distal anastomosis is coming to a ­conclusion, the left ventricular vent is switched off to allow passive filling of the heart. A ‘Y’-cannula is placed in the graft and used for venting and delivering a hotshot prior to clamp removal so the anastomotic patency can be confirmed. Any remedial sutures are placed if needed, and then after a thorough de-airing drill, the cross-clamp is removed.

Suggested Reading Cooley DA.  A brief history of aortic aneurysm surgery. Aorta (Stamford). 2013;1(1):1–3. Coselli JS.  Evolution of aortic arch repair. Tex Heart Inst J. 2009;36(5):435–7. Xydas S, Mihos CG, Williams RF, LaPietra A, Mawad M, Wittels SH, et  al. Hybrid repair of aortic arch aneurysms: a comprehensive review. J Thorac Dis. 2017;9(Suppl 7):S629–34.

Part VI Surgery of the Failing Heart

Cardiopulmonary Transplantation: An Overview

17

Marius Berman

Heart Transplantation

Urgent Inpatient Referral

The first interhuman, orthotopic, heart transplant was performed by Dr. Christiaan Nethling Barnard at the Groote Schuur hospital in Cape Town 1967. The patient survived for 18 days. In the current era, there are approximately 5000 transplants performed worldwide each year. The outcomes are excellent. The most significant development in the past 10 years is the advent of hearts that have become usable after circulatory (DCD) death. It requires utilisation of novel technologies, with in- or ex situ organ perfusion, to resuscitate and assess the quality of the heart. The outcome of heart transplantation with DCD hearts is equal to heart transplantation after brain death (DBD) [1]. The indication, contraindications [2], and outcomes are as follows.

• • • •

Indications

Contraindications • • • • • •

• •

Ambulatory • Patients on optimal medical therapy with symptoms on exertion • More than 2 hospitalisation episodes/year • Deterioration of renal function or inability to clear heart failure congestion • Worsening right ventricular function with rising pulmonary artery pressure • High natriuretic peptide • Ventricular arrhythmias • Anaemia, weight loss, hyponatremia, or liver dysfunction attributable to heart failure M. Berman (*) Royal Papworth Hospital NHS Foundation Trust, Cambridge, UK e-mail: [email protected]

The inability to wean inotropic support Mechanical circulatory support for cardiogenic shock Pulmonary oedema and ventilation Refractory ventricular arrhythmias

• •

Active infection Symptomatic cerebral or peripheral vascular disease Diabetes mellitus with end-organ damage Current or recent neoplasm Forced expiratory volume in 1 s (FEV1) or forced vital capacity (FVC) 60 mmHg, transpulmonary gradient >15 mmHg and/or pulmonary vascular resistance >5 Wood units. Suitability is assessed with pharmacological management or bridging with mechanical circulatory support. Psychological factors Obesity (BMI >35 kg/m2)

Outcomes The outcomes are largely dependent on donor and recipient factors—to name some—donor age, ischemic time, recipient pathology, previous surgery, institution volume, geographical region, and many others (Figs. 17.1 and 17.2). The full report is published on a yearly basis by the International Society of Heart and Lung Transplantation [3].

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_17

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126

M. Berman

a

b

Fig. 17.1  Adult heart recipient survival by era (a) and by region (b). DCM dilated cardiomyopathy, ICM ischaemic cardiomyopathy, HCM hypertrophic cardiomyopathy, RCM restrictive cardiomyopathy, CHD congenital heart disease. (From Perch et al. [3]; with permission)

(DCD). This potentially requires in situ or ex vivo organ perfusion and ventilation to assess its quality. The matching of donor and recipient is affected by multiple variables.

Indications This is a multidisciplinary decision. Patients must meet the following criteria [4]:

Fig. 17.2  Adult heart transplant recipient survival by pathology. DCM dilated cardiomyopathy, ICM ischaemic cardiomyopathy, HCM hypertrophic cardiomyopathy, RCM restrictive cardiomyopathy, CHD congenital heart disease. (From Perch et al. [3]; with permission)

• High (>50%) risk of death due to lung disease within 2 years if lung transplantation is not performed. • High (>80%) likelihood of surviving at least 90 days after lung transplantation. • High (>80%) likelihood of 5-year post transplant survival from a general medical perspective provided adequate graft function.

Lung Transplantation

Contraindications

Lung transplantation progressed significantly in the past 10  years. Vast majority are performed without mechanical support, with some units using extracorporeal membrane oxygenation (ECMO) or cardiopulmonary bypass. The access is via thoracotomy, sternotomy, or clamshell with recently reports of robotic-assisted lung transplants. One of the major developments in lung transplantation is the increasing use of organs from donation after circulatory death

• A recent history of malignancy; 5-year disease free interval required • Poorly controlled significant dysfunction of another organ • Coronary disease, non-amenable to revascularisation • An uncorrectable bleeding disorder • Poorly controlled infection • Chest wall or spinal deformity which will affect graft function

17  Cardiopulmonary Transplantation: An Overview

• • • •

127

BMI >35 kg/m2 Noncompliance with medication Psychological factors Illicit substance abuse or dependence

Outcomes Outcomes of Chronic Obstructive Pulmonary Disease (COPD) recipients are better than other pathologies (Fig. 17.3). In addition, the prognosis of double lung transplantation is better compared to single lung transplantation (Fig. 17.4). The report is published on a yearly basis by the International Society of Heart and Lung Transplantation.

Fig. 17.4  Adult lung transplant outcome of single versus double lung transplant. COPD chronic obstructive pulmonary disease, other— A1ATD alpha 1 antitrypsin deficiency, CF cystic fibrosis, IPAH idiopathic pulmonary hypertension, IPF interstitial pulmonary fibrosis, retransplantation. (From Perch et al. [3]; with permission)

Conclusion

Fig. 17.3  Adult lung transplant outcome by diagnosis. (From Perch et al. [3]; with permission)

Cardiopulmonary transplantation has become a fully accepted therapy with excellent results. Organ donation remains the rate limiting step but has been enhanced by recent changes in the law to an opting out system and the advent of the availability of DCD organs. Until genetically engineered xenotransplantation becomes a reality and/or mechanical replacement comes of age, human organ donation will be the mainstay of treatment for cardiopulmonary failure.

References 1. Messer M, Cernic S, Page A, et  al. A 5-year single-centre early experience of heart transplantation from donation after circulatory death donors. J Heart Lung Transplant. 2020;39(12):1463–75. 2. Bhagra S, Pettit S, Parameshwar J.  Cardiac transplantation: indications, eligibility and current outcomes. Heart. 2019;105:252–60. 3. Perch M, Hayes D, Cherikh WS, Zuckermann A, Harhay MO, Hsich E, International Society for Heart and Lung Transplantation, et  al. The international thoracic organ transplant registry of the International Society for Heart and Lung Transplantation: thirty-­ ninth adult lung transplantation report-2022; focus on lung transplant recipients with chronic obstructive pulmonary disease. J Heart Lung Transplant. 2022;41(10):1335–47. https://doi.org/10.1016/j. healun.2022.08.007. 4. Weill D. Lung transplantation: indications and contraindications. J Thorac Dis. 2018;10(7):4574–87.

18

Lung Transplantation Pradeep Kaul, Lu Wang, and Mohamed Osman

Procurement

The steps for procurement of a lung block are as follows:

Lungs are susceptible to damage and injury stemming from resuscitation, ventilator-associated infection, barotrauma, and brainstem death process. Therefore, lung allografts have the lowest utilisation rate for transplantation among all the solid organs. Due to the increasing disparity between waiting list and lung transplant activities and change in donor demographics, the donor selection criteria have evolved over time. Table  18.1 summarises the ideal and extended criteria and contraindications for donor selection. Once donor lungs are provisionally accepted by a transplant centre, donor operation proceeds at a time agreed by the retrieval teams and donor hospital. Donor operation is a continuous process of allograft optimisation and procurement.

1. Median sternotomy is the commonest incision for cardiothoracic organ procurement. The pericardium is then opened with an inverted “T” shaped incision. 2. Two or three pericardial stay sutures are placed on each side of the opened pericardium. The stay sutures are secured with artery forceps for easy mobilisation of the pericardium to facilitate access to the bilateral pleural spaces. Both pleurae are opened, and the lungs are inspected for the final component of allograft assessment. Table 18.2 lists the main considerations of the intraoperative evaluation. If the recipient centre formally accepts the lung allograft with the final piece of information, the retrieval team can proceed to dissection in preparation for lung procurement.

Table 18.1  Main donor selection criteria for lung transplantation Extended-criteria donor 45–75 years

Contraindication >75 years Aspiration pneumonia

Past medical history Social history Ventilation Oxygenationa Bronchoscopy

Ideal donor 25–45 years No chest trauma No aspiration Non-diabetic No smoking history 350 mmHg • Clear bronchoscopy

Diabetes mellitus 20 pack years history of smoking

Chest X-ray Ischaemic time

Clear chest X-ray  16 mmHg) and further mechanical support required either in the form of an intra-aortic balloon pump (IABP) or inotropes for:- systolic blood pressure   65 (few patients above the age of 65 have been transplanted before). BMI > 35. Diabetes with microvascular complications not including non-proliferative retinopathy. Sepsis and active infections.

Donor Inclusion Criteria ∙ Controlled DCD (Maastricht Category 3 and 4) ∙ Age ≤ 50 years ∙ Weight ≥ 50 kg ∙ Weight ≥ 30 kg—if suitable paediatric recipient at specialist paediatric centre discuss • ∙ Consent/authorisation obtained from next of kin/organ donor register. • • • •

Maastricht criteria 3 is defined as a donor who has had a cardiac arrest in ITU after withdrawal of life supporting treatment. Maastricht criteria 4 is defined as a donor who has had a cardiac arrest after the declaration after brain neurological death.

Donor Exclusion Criteria • • • • • • • • • •

∙ Previous cardiac surgery ∙ Previous midline sternotomy ∙ Valvular heart disease ∙ Congenital heart disease ∙ Significant coronary artery disease ∙ Chronic atrial fibrillation ∙ Insulin dependent diabetes ∙ Virology: HIV+ ∙ Current IV drug abuse ∙ Tumour with high risk of transmission according to SABTO guidelines.

The DCD recipient is similar to the DBD recipient in that they also have refractory ESHF not amenable to medical therapy. Some DCD recipients may be eligible for DBD hearts, others may not have been eligible for DBD hearts but may consent for a DCD heart instead of receiving no organ at all. However, as the field of DCD transplantation develops, it will most likely be the case that DCD organs will be more widely used and all patients will be consented for both DBD and DCD hearts. The current criteria for a recipient—either DBD or DCD was put together by Brenner and colleagues in 2011. They are split into absolute contraindications and relative contraindications.

Relative Contraindications Poorly controlled diabetes—with a glycosylated haemoglobin >7.5%. Chronic infections—usually of the brain, liver, or lungs. History of non-adherence. Recent pulmonary embolism. Pharmacological immunosuppression. Peripheral or cerebrovascular disease. Skeletal myopathies. Psychosocial issues. Substance abuse.

Ex Situ Machine Perfusion ESMP is an attractive method for heart preservation in DCD transplantation. Ischaemia is the main challenge faced by DCD transplantation. Therefore, perfusing the heart with an oxygenated, energy rich solution is not only desirable, but

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one would argue almost essential to ensure that the graft quality is preserved. Whilst ESMP shows a great deal of promise, it is still in its infancy in cardiac transplantation and there are several issues that it must overcome to ensure that it is effectively utilised by centres worldwide. The first would be the exorbitant cost. At the moment, each donor run costs in excess of $50,000 and therefore is not financially feasible for many centres. In addition to the high cost, hearts preserved with ESMP fall victim to oedema that even the high levels of mannitol in the preservation solution cannot prevent. The longest that a heart has been preserved with clinically is… and it is unlikely that hearts will be preserved for longer until the problem of oedema has been overcome. The second issue that ESMP faces is the lack of a suitable marker of transplantability. In earlier years, lactate was used—based off limited work done in DBD heart transplants. The logic for using lactate was that a metabolically competent, healthy heart should be able to utilise lactate. Therefore, one would expect the lactate to trend downwards, or for there to be a significant arterio-venous difference in lactate levels. However, clinically it has been shown that there is absolutely no correlate between lactate levels and clinical outcomes. Therefore, there is an urgent need for a suitable marker of transplantability to ensure that appropriate hearts are transplanted and equally important to ensure that suitable hearts are not mistakenly rejected.

Future Directions DCD is still in its infancy in many centres. Results so far have demonstrated that DCD transplantation is a safe and effective method of transplantation. There is a need to ensure

S. Large and J. O. Louca

that this method of transplantation becomes more widely utilised and can further reduce the ever-growing waiting lists of recipients awaiting heart transplants.

Suggested Reading Ali AA, White P, Xiang B, Lin HY, Tsui SS, Ashley E, et  al. Hearts from DCD donors display acceptable biventricular function after heart transplantation in pigs. Am J Transplant. 2011;11(8):1621–32. Cernic S, Page A, Messer S, Bhagra S, Pettit S, Dawson SN, et  al. Lactate during ex-situ heart perfusion does not predict the requirement for mechanical circulatory support following donation after circulatory death (DCD) heart transplants. J Heart Lung Transplant. 2022;41(9):1294–302. Dhital KK, Iyer A, Connellan M, Chew HC, Gao L, Doyle A, et  al. Adult heart transplantation with distant procurement and ex-vivo preservation of donor hearts after circulatory death: a case series. Lancet. 2015;385(9987):2585–91. Louca J, Shah A, Messer S, Patel N, Sanghera R, Manara A, et  al. Clinical outcome following heat transplantation of 59 Tanrp donor hearts. An international experience. J Heart Lung Transplantation. 2017;36(12):1311–8 Mehra MR, Uriel N, Naka Y, Cleveland JC Jr, Yuzefpolskaya M, Salerno CT, et  al. A fully magnetically levitated left ventricular assist device. N Engl J Med. 2019;380(17):1618–27. Messer S, Cernic S, Page A, Berman M, Kaul P, Colah S, et  al. A 5-year single-center early experience of heart transplantation from donation after circulatory-determined death donors. J Heart Lung Transplant. 2020;39(12):1463–75. Rose EA, Gelijns AC, Moskowitz AJ, Heitjan DF, Stevenson LW, Dembitsky W, et al. Long-term use of a left ventricular assist device for end-stage heart failure. N Engl J Med. 2001;345(20):1435–43. Starling RC, Moazami N, Silvestry SC, Ewald G, Rogers JG, Milano CA, et  al. Unexpected abrupt increase in left ventricular assist device thrombosis. N Engl J Med. 2014;370(1):33–40.

Part VII Pulmonary Thromboendarterectomy

Pulmonary Endarterectomy Surgery

22

David P. Jenkins

The most common indication for pulmonary endarterectomy (PTE) is chronic thromboembolic pulmonary hypertension (CTEPH). Rarer indications include debulking of pulmonary artery sarcoma and disobliterating stenosis caused by pulmonary artery vasculitis. CTEPH occurs in up to 3% of people following a pulmonary embolism. The actual cause is uncertain, but pathologically there is failure of clot lysis, with organisation into fibrotic obstruction within the pulmonary arteries. This manifests as laminated thrombus within the main pulmonary artery branches, or lobar occlusion, or web-like stenoses at the segmental branches and smaller subsegmental webs and occlusions. These macroscopic obstructions increase pulmonary vascular resistance resulting in pulmonary hypertension and ultimately right heart failure. As pulmonary hypertension develops, the microcirculation maladapts to increasing pressure with wall thickening at arteriolar level that increases the PVR further, the two-compartment model. More recent pathological analysis has suggested further abnormalities in the microcirculation with involvement of the bronchial artery connections and abnormalities in pulmonary venules. CTEPH can be difficult to diagnose as the symptoms are non-specific, usually exertional breathlessness, and some patients have no history of the acute event. There are no early signs until progressive right heart failure develops. However, awareness and diagnosis are increasingly important as CTEPH is the most treatable form of precapillary pulmonary hypertension. Enlarged pulmonary arteries and dilatation of the right heart can be seen on a chest X-ray. An echocardiogram will show a dilated right heart with evidence of right ventricular hypertrophy, impaired right ventricular function, tricuspid regurgitation, and a small compressed underfilled left heart. A ventilation/perfusion scan will show wedge shaped segmental perfusion defects without corresponding

D. P. Jenkins (*) Department Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected]

ventilation defects, so-called mismatched. Confirmation of PH requires a right heart catheter to measure pulmonary artery pressure and calculate cardiac output and pulmonary vascular resistance. Imaging of the pulmonary circulation is required to assess operability. CTPA, MRI, and conventional pulmonary angiograms are used.

Surgical Technique Set Up The approach is via a median sternotomy incision with the patient in a supine position as for usual cardiac surgery. The key difference between pulmonary endarterectomy and standard cardiac surgery is the requirement for deep hypothermic arrest (DHCA). There are therefore some additional anaesthetic, monitoring and perfusion requirements. All patients have a PA catheter to monitor pre- and post-cardiopulmonary bypass (CPB) PA pressures. Peripheral (nasopharyngeal) and central (bladder) temperature probes are required to monitor cooling and warming rates on CPB as patients are cooled to 20 °C and slowly rewarmed to 36 °C. A centrifugal pump is used on the CPB machine and a leukocyte filter incorporated in the circuit. A cooling/warming mattress is placed beneath the patient and a cooling cap wrapped around the head (rather than ice). Near infrared spectrometry (NIRS) is used to monitor brain oxygen saturation.

Cardiopulmonary Bypass The institution and management of CPB are essential parts of the PTE operation. Good venous drainage is essential. The aorta is cannulated in the usual position anteriorly just proximal to the pericardial reflection. I use a standard 2-stage venous cannula positioned in the body of the right atrium and inferior vena cava via a purse string in the appendage. An additional straight venous cannula is inserted in the right

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_22

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atrium and directed into the superior vena cava (SVC). CPB and cooling can then be commenced, and vents are placed. The tissue between the aorta and main pulmonary artery is divided using low power diathermy. Tapes are placed around the aorta and pulmonary artery utilising the transverse sinus. Vents are placed in the main PA and via the right superior pulmonary vein to the left ventricle so that both sides are the heart are well drained to avoid distension when ventricular fibrillation occurs during cooling. A cardiplegia cannula is placed in the aorta for delivery of antegrade cold blood cardioplegia. Mobilisation of the SVC is important to gain adequate access to the right PA.  I choose to do this from the patient’s left side prior to starting the right PA dissection. I separate the fascia between the right PA and SVC with low power diathermy and then blunt dissection to create a tunnel under the SVC just wider than the diameter of the right PA.  The pericardium is then incised with diathermy vertically upwards, allowing the SVC to be retracted further laterally. A small self-retaining retractor can then be inserted between the SVC and aorta to expose the right PA (Fig. 22.1). The pulmonary artery is opened and endarterectomy dissection is commenced prior to cardioplegic arrest and DHCA.  Progress is continued until the operating field is obscured by blood in the pulmonary artery. Most patients with CTEPH have a well-developed compensatory bronchial collateral circulation and it is for this reason that the DHCA is required to see enough to perform a safe distal endarterectomy dissection. In most cases dissection on the one side can be completed in a single 20-min DHCA session; clinical practice and cognitive function studies have demonstrated that this period is well tolerated at 20 °C. If further time is required for more difficult distal dissection, then a further arrest can be made following a 10-min period of reperfusion (Fig. 22.1).

Endarterectomy The right pulmonary artery is opened with a longitudinal incision taking care to avoid the upper lobe branch and curve the incision distally towards the lower lobe. The incision can be extended laterally up to the origin of the middle lobe

Fig. 22.1  Exposure of the right pulmonary artery and arteriotomy

D. P. Jenkins

Fig. 22.2  Development of the dissection plane

branch orifice to give better exposure to the lower lobe branches. Stay sutures are placed on the artery edges. Development of the dissection plane is fundamental to the success of the endarterectomy. If there is thickening and laminated thrombus proximally, this can sometimes be developed at the arteriotomy from the cut edge of the artery. More usually the endarterectomy plane is created with a beaver blade in the posterior wall of the artery by making a small flap that can be extended by blunt dissection (Fig. 22.2). The plane may start very thin proximally but usually thickens distally. The correct plane is usually the one that extends most easily, leaving a pearly white smooth residual vessel wall. Usually any atherosclerotic yellow plaques are lifted clear with the dissected specimen. If the residual wall becomes more fibrous or pink/purple-tinged, then the plane is too deep. Once the correct plane is achieved and extended circumferentially around the artery, it can be extended distally into lobar, segmental, and subsegmental branches. Any proximal laminated old thrombus should be cleared to allow room to visualise and dissect the remainder of the artery. By mechanical traction on the endarterectomised specimen, the residual vessel wall is pushed away using a blunt ended fine metal sucker (Fig. 22.3). The dissection is advanced cm by cm following every branch. The fibrous occlusive ‘tails’ are then pulled clear as they taper distally into a fine strand. It is important to visualise every segmental branch and retrieve any broken tails. The pattern of disease can be quite diverse from proximal laminated bulky thrombus to occlusive tails and to very fine distal webs. The latter small distal webs can be targeted directly by grasping the centre with a forceps and teasing free (Fig. 22.4). Once all disease is removed, the circulation is restarted, and the arteriotomy closed with 5/0 prolene. The procedure is then repeated on the left side. For the left dissection, the main pulmonary artery is opened from just distal to the pulmonary valve up to the pericardial reflection. To improve visualisation of the left lower lobe branches, some surgeons elevate the heart, but I usually rely on manual retraction with a handheld eyelid type retractor. Examples of the different types of disease removed can be seen in Figs. 22.5, 22.6, and 22.7.

22  Pulmonary Endarterectomy Surgery

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Fig. 22.4  Small distal web in subsegmental branch

Fig. 22.3  Instruments for pulmonary endarterectomy

Fig. 22.5  Example of endarterectomy specimen, subsegmental disease

168 Fig. 22.6  Example of endarterectomy specimen, fine segmental ‘tails’

Fig. 22.7  Example of endarterectomy specimen, laminated thrombus on right side

D. P. Jenkins

22  Pulmonary Endarterectomy Surgery

Concomitant Procedures If further procedures are required, they are usually performed during this rewarming period. Coronary and valve surgery may be necessary especially in older patients. Although tricuspid regurgitation is often a feature of the presentation, repair is usually unnecessary as once the PVR is reduced and the right heart remodels, it regresses.

Separation from CPB Once fully rewarmed, preparation is made to wean from CPB. The lungs are ventilated with a protective reduced tidal volume regimen during the rewarming phase. Our standard practice is to use low dose dopamine and avoid inodilators. I aim to fill to approximately 50% of the pre-CPB right atrial pressure and gradually reduce CPB flow litre by litre aiming to keep the right heart as empty as possible and the PA pressure as low as possible, but achieve adequate cardiac output and perfusion pressure. The latter is critical for optimal right ventricular function and sometimes vasoconstrictors are

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required. It is an important time and requires cooperation between anaesthetists, perfusionist, and the surgeon. Many of the specific serious potential complications of PTE surgery will become apparent at this time, airway haemorrhage, reperfusion pulmonary oedema, and residual PH with right heart failure. Closure Meticulous haemostasis is required as we try to avoid use of blood products. Otherwise decannulation, reversal of heparin and closure are as for standard cardiac surgery. We leave two pericardial drains and open the right pleura, with a further drain to reduce the risk of pericardial effusion and late tamponade.

Suggested Reading Delcroix M, Torbicki A, Gopalan D, Sitbon O, Klok FA, Lang I, et al. ERS statement on chronic thromboembolic pulmonary hypertension. Eur Respir J. 2021;57:2002828. Jenkins DP, Tsui SS, Taghavi J, Kaul P, Ali J, Ng C.  Pulmonary thromboendarterectomy—the Royal Papworth experience. Ann Cardiothoracic Surg. 2022;11(2):128.

Part VIII Pericardial Disease

Pericardiectomy for Constrictive Pericarditis

23

Jason Ali

The heart is found within the pericardial sac. The pericardium is divided into two layers—the fibrous pericardium and the serous pericardium (Fig. 23.1). The fibrous pericardium is an outer fibroelastic layer. The inner serous pericardium, formed of a thin layer of mesothelial cells is invested by the heart, thus creating two layers—the visceral serous pericardium which is continuous with the outer layer of the epicardium and the parietal serous pericardium which is continuous with the inner layer of the fibrous pericardium (Fig. 23.2). The potential space between these two layers is the pericardial cavity. Constrictive pericarditis describes a physiological state whereby the volume of the heart is restricted by the pericardium, which is typically fibrotic, calcified and thickened (Fig. 23.3). The constrictive pericardium limits cardiac filling leading to diastolic heart failure. Worldwide, the commonest cause of constrictive pericarditis is tuberculosis. This is rarer in developed countries where the commonest causes are idiopathic or related to prior cardiac surgery or irradiation. Other less common causes include mesothelioma, drug-induced, sarcoidosis, carcinoid syndrome, uraemia and following myocardial infarction. A septic pericarditis can also be seen following a range of bacterial or viral infections and may be associated with pleural effusion and pneumonia.

Patients with constrictive pericarditis experience symptoms of both left and right heart failure and display some classic signs including Kussmaul’s sign (paradoxical increase in JVP occurring during inspiration) and pulsus paradoxus (an exaggerated fall in a patient’s systolic pressure during inspiration by greater than 10 mmHg). Imaging usually reveals a markedly thickened and calcified pericardium (Fig. 23.4) with evidence of constrictive physiology. There are some physiological similarities with restrictive cardiomyopathy, but the diagnosis can be differentiated with careful imaging. Constrictive pericarditis is typically a chronic progressive condition, and surgical pericardiectomy is the only definitive treatment available, but leads to a complete symptomatic relief. In the acute/early-stage steroids may ameliorate the condition, but progression will lead to the need for surgical release of the heart. Pericardiectomy entails mechanical release of the heart by excising as much of the pericardium as possible. The standard procedure is to release the heart from phrenic nerve to phrenic nerve. If there is severe basal and posterior constriction, then diaphragmatic and posterolateral excision of the pericardium is necessary as far as possible to minimise the persistence of restriction to filling of the left side of the heart.

J. Ali (*) Department of Cardiothoracic Surgery, Royal Papworth Hospital, Cambridge, UK e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1_23

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174

J. Ali

Fig. 23.1 Low-powered section showing the layers

The heart wall

Parietal pericardium

Visceral pericardium

Myocardium Endocardium

Pericardial cavity

23  Pericardiectomy for Constrictive Pericarditis

175

Fig. 23.2 High-powered section showing the cell types

a

d

Fig. 23.3  Constrictive pericarditis

b

c

e

f

176

Fig. 23.4  Axial contrast CT scan demonstrating a calcified and thickened pericardium (grey arrows)

Surgical Correction Pericardiectomy is typically performed through a median sternotomy incision. The aim is to achieve complete removal of all thickened pericardium and epicardium from the left and right ventricle and diaphragm, whilst preserving both phrenic nerves. Clearance of pericardium from ‘phrenic to phrenic’ alone is likely to fail to release a significant proportion of the left ventricle leading to a higher incidence of recurrent constrictive pericarditis. In the majority of cases, cardiopulmonary bypass can be avoided, unless there is marked adherence to the myocardium. In these cases, cardiopulmonary bypass may be used with or without aortic cross-clamping. The conventional teaching is to consider decorticating the left ventricle first, to avoid pulmonary oedema developing due to release of the right ventricle whilst the left is still constricted. However, this is rarely performed as the theoretical

J. Ali

risk of pulmonary oedema is not observed in practice, and this approach is not possible via median sternotomy and would require a thoracotomy. Complete resection of the pericardium overlying the atria is often technically difficult as a result of the weakness of the atrial wall but should be done as leaving it risks residual constrictive haemodynamics. Densely adherent and calcified pericardium overlying the right atrium will need very careful and painstaking work but should be attempted. Of critical importance is avoidance of injury to the phrenic nerves as this will lead to significant postoperative morbidity. Particular attention should be made to identify these early. This is achieved by examining the pericardium from the intra-pleural surface upon which the nerves will be found. The left side is more difficult as it frequently lies quite posteriorly. However, the operator will know that it lies anterior to the hilum of the lung. (Fig. 23.5) but this can be challenging particularly in constrictive pericarditis following cardiac surgery. The fibrous and serous pericardial layers should be dissected off the heart sharply, typically using scissors. It can be difficult to identify the correct plane and there can be bleeding from the raw epicardial surface (hence the aim should be to perform without cardiopulmonary bypass and systemic heparinisation if possible). Great care should be taken to identify and thus avoid injury to the coronary arteries (Fig. 23.6). If it is not possible to dissect areas of constrictive pericardium due to strong adherence to the epicardium, and alternative approach is to score the pericardium sharply with multiple horizontal and vertical lines, creating a grid-like appearance which does allow for some release of constriction and ventricular expansion during diastole (Fig. 23.7). Post-operatively careful medication with diuretics and rhythm control is important as right ventricular overload and pulmonary oedema are easily precipitated as the restricted blood enters the right side more easily causing rapid dilation.

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23  Pericardiectomy for Constrictive Pericarditis Fig. 23.5  Anatomy of the phrenic nerves in relation to the hilum of the lung and the mediastinum from both the right and left

Clavicle

Right superior intercostal vein

Second ganglion of sympathetic trunk Intercostal muscles Sympathetic trunk Intercostal nerves Azygos vein Oesophagus Parietal pleura (costal part) Posterior intercostal arteries Posterior intercostal veins

Greater splanchnic nerve Central tendon of diaphragm Diaphragm

Right subclavian artery Subclavius Right subclavian vein Trachea

Vagus nerve (cardiac branches) Superior vena cava

Pulmonary plexus of vagus nerve

Thymus Pericardiophrenic artery Pericardiophrenic vein Arch of azygos vein

Right main bronchus Right pulmonary arteries Myocardium Right phrenic nerve Parietal pleura (costal part) Right pulmonary veins

Sympathetic trunk (Communicating branches)

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J. Ali

Suggested Reading Hemmati P, Greason KL, Schaff HV.  Contemporary techniques of pericardiectomy for pericardial disease. Cardiology Clinics. 2017;35(4):559–66. https://doi.org/10.1016/j.ccl.2017.07.009. Liu VC, Fritz AV, Burtoft MA, Martin AK, Greason KL, Ramakrishna H.  Pericardiectomy for constrictive pericarditis: analysis of outcomes. J Cardiothorac Vasc Anesth. 2021;35(12):3797–805. https:// doi.org/10.1053/j.jvca.2021.02.020. Miranda WR, Oh JK.  Constrictive pericarditis: a practical clinical approach. Prog Cardiovasc Dis. 2017;59(4):369–79. https://doi. org/10.1016/j.pcad.2016.12.008. Oh NA, Hennecken C, Van den Eynde J, Doulamis IP, Avgerinos DV, Kampaktsis PN.  Pericardiectomy and pericardial window for the treatment of pericardial disease in the contemporary era. Curr Cardiol Rep. 2022;24:1619–31. https://doi.org/10.1007/ s11886-­022-­01773-­7.

Fig. 23.6  Intraoperative image demonstrating the markedly thickened pericardium

Fig. 23.7  Heart with scored pericardium

Index

A Abnormal papillary muscles, 64 Activated clotting time (ACT), 149 Adult lung transplant outcome, 127 Alfieri edge-to-edge technique, 66, 83 Annular decalcification, 66, 91 Annular reconstruction, 101, 102 Annuloplasty devices, 68 Annuloplasty ring, 101 Annuloplasty sutures, 57, 68, 70, 84–86 Annulus, 68 Anterior leaflet augmentation, 111 Anterior mitral valve leaflet, 97, 99 Anterior septal rupture, 15 Anterior thoracotomy incision, 133 Anterolateral/posteromedial commissure, 98 Anterolateral thoracotomy, 134 Antibiotics, 98 Anticoagulation, 9 Aortic anastomosis, 143, 144, 152 Aortic annulus, 30 Aortic arch, replacement of, 118, 120 Aortic cross-clamp, 56 Aortic dissection, 118 Aortic regurgitation, 24 Aortic root complex, 45 Aortic root enlargement, geometric consideration for, 35 Aortic root replacement, 43 Aortic root suction, 4 Aortic valve, 113 Aortic valve prosthesis, 39 Aortic valve replacement, 29, 35 aortic valve anatomy, 26 aortic valve excision and debridement, 28, 29 aortic valve sizing, 29 aortotomy, 27, 28 myocardial protection, 29 surgical techniques, 25, 26 Arch anastomoses, 120 Ascending aorta, 120, 121 Atrial retractor, 90 Atrio-ventricular annular dilatation, 89 Atrioventricular dilation, 69 Atrioventricular groove, 101 Atrioventricular junction, 77, 105 Axillary arteries, 118, 119 B Bacteraemia, 95 Balloon-tipped coronary sinus cannula, 35 Barlow’s deformity, 86 Barlow’s valve, 65, 66, 83, 86

Bayonet needle mount, 7 Bentall operations, 48 Bilateral lung ventilation, 134 Bileaflet mechanical valves, 31 Billowing valve, 65 Bioprosthetic tricuspid valve, 113 Blood pressure, 10 Bovine pericardium, 98 Bovine pericardium patch reconstruction, 101 Bronchial anastomosis, 136 C Calcific mitral stenosis, 24 Cardiac allograft vasculopathy, 147 Cardiac chamber muscle, 105 Cardiectomy, 131 Cardiopulmonary bypass (CPB), 9, 33, 44, 49, 56, 118, 120, 140, 165, 166 Cardiopulmonary bypass tubing, 56 Cardio-pulmonary transplantation, 127 Cardiothoracic retrieval team, 130 Carpentier functional classification, 63 Caudal traction, 151 Caval snares, 57 Central venous cannulation, 118 Chronic thromboembolic pulmonary hypertension (CTEPH), 165, 166, 169 Clam-shell or transverse thoraco-sternotomy, 134 Classical de Vega suture technique, 108 Clover stitch, 109 Collateral ventilation, 137 Commissural plication, 66 Commissural prolapse, 65, 78 Concomitant procedures, 169 Concurrent coronary artery bypass graft surgery, 14 Conduction tissue, 113 Conduit shortage, 8 Constrictive pericarditis, 173, 175, 176 Conventional open-heart surgery, 14 Conventional teaching, 176 Cooley clamp, 118 Cordal replacement, 66, 78 Coronary arteries, 6 Coronary artery bypass grafting (CABG) anaesthetics, 9 anastomoses to anterior wall, 10, 11 conduit harvest, 10 inferior wall anastomoses, 11 lateral wall, 11 operating room setup and preparation, 9 postoperative management, 12 procedure, 3–7

© The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 F. C. Wells (ed.), Atlas of Cardiac Surgery, Springer Surgery Atlas Series, https://doi.org/10.1007/978-3-031-43195-1

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180

Index

sequence of anastomoses, 10 set-up and positioning, 10 surgical technique, 9 technical considerations, 7 Coronary obstruction, 20 Coronary perfusion, 47 Coronary sinus, 113 Custom prostheses, 43

Heart–lung transplantation donor heart-lung implantation, 151–153 indications, 149 preparation of recipient, 149–151 Hemisternotomy, 52 Heparin, 3 Hilar structures, 150 Horizontal mattress sutures, 45

D De Vega procedure, 105 “de Vega” technique, 106 De-airing, 47, 51 Deep cleft, 75 Deep hypothermic arrest (DHCA), 165 Deep pericardial sutures, 11 Dissection plane, 166 Distal anastomoses, 4–6 Distal trachea, 151 Domino heart transplant, 150 Donation after circulatory death (DCD), 126, 132 Donor heart preparation, 142, 146 Donor pulmonary venous cuff, 137, 138

I Implantable left ventricular assist devices (LVADs), 147 Inferior caval cannulation, 56 Inferior leaflet imbrication, 110 Inferior left ventricular mass regression, 35 Inferior vena cava anastomosis, 144, 153 Inferior wall anastomoses, 11 Inferior wall target vessel revascularisation, 12 Infero-lateral commissural prolapse, 81 Intra-annular technique, 31 Intraoperative transoesophageal echocardiogram, 35 IVC anastomosis, 144

E Echocardiography, 23 Embolisation, 98 Emergency hospital admission, 19 Emergency surgery, 117 Endarterectomy, 166, 168 Endocarditis, 86 Endoscopic/open bridging technique, 9 Enterococcus Streptococcus faecalis, 95 Eustachian valve, 57 Exercise echocardiography, 23 Extensive annular calcification, 92 External defibrillation pads, 58 Extracorporeal membrane oxygenation (ECMO), 126 F Flail leaflet, 65 Free wall rupture, 14 Frozen elephant trunk (FET) arch replacement, 117 Frozen elephant trunk device, 118 G Gentle traction, 98 Gore-Tex suture, 79 H Heart transplantation contraindications, 125 indications, 125 outcomes, 125 Heart valve surgery aortic regurgitation, 24 aortic stenosis, 24 mitral regurgitation, 23, 24 mitral stenosis, 24 tricuspid regurgitation, 24

K Konno-Rastan Technique, 35, 39 Kussmaul’s sign, 173 L Lateral wall target vessel revascularisation, 11 Leaflet coaptation, 65 Leaflet height reduction, 72, 76 Leaflet perforation, 98 Leaflet prolapse, 65 Leaflet resection, 65 Leaflet techniques Alfieri edge to edge technique, 78, 83 commissural prolapse, 78 cordal replacement, 78 leaflet height reduction, 72, 76 quadrangular resection of mural leaflet, 70 sliding annuloplasty, 70, 72 triangular resection, 72 Leaflet tethering, 113 Leaflet transfer, 66 Left and right coronary ostia, 31 Left and right coronary sinuses, 31 Left anterior descending (LAD), 3 Left atrial anastomosis, 142 Left internal mammary artery (LIMA), 3 LIMA arteriotomy, 6 Limb ischaemia, 117 Lung dissection process, 132 Lung transplantation common incisions for, 134 contraindications, 126, 127 implantation, 133–137 indications, 126 intraoperative findings for, 130 main donor selection criteria for, 129 outcomes, 127 procurement, 129, 130, 132, 133 Lung ventilation, 153

Index M Manouguian- Nunez Technique, 35, 37, 39 Mechanical Circulatory Support (MCS) classification, 155, 156 complications, 157 DCD donor and recipient, 161 DCD transplantation, 160 ex-situ machine perfusion, 161, 162 implantation of LVAD, 156, 157 indications, 156 purpose, 155 total artificial heart and biventricular assisted devices, 159, 160 Mechanical valves, 113 Median sternotomy, 44, 118, 149 Mesenteric ischaemia, 117 Midline sternotomy, 67 Minimal access procedures, 66 Minimally invasive aortic valve replacement (MIAVR) cardiopulmonary bypass, 49, 50, 52 closure, 52 de-airing, 51 dissection, 49 incision, 49 post-operative care, 52 procedure, 50 venting, 50 Minimally invasive direct access coronary artery bypass (MIDCAB), 9 Mitral leaflets, 64 Mitral regurgitation (MR), 23, 95, 105 Mitral stenosis, 24, 89 Mitral valve, 19, 64, 86, 87 horizontal trans-septal bi-atrial approach, 58 minimally access approaches, 58, 59, 62 patient positioning, 55 robotic mitral valve surgery, 62 standard left atriotomy, 57 superior left atrial roof approach, 58 surgical incision, 55–57 vertical trans-septal bi-atrial approach, 57 Mitral valve annulus, 95 Mitral valve endocarditis, 102 annular reconstruction, 101, 102 echocardiographical findings, 95 indications for surgery, 98 leaflet reconstruction, 98, 100 surgical strategy, 98 Mural leaflet, 65, 92, 93 Myocardial and leaflet inflammation, 89 Myocardial infarction, 13 Myocardial inflammation, 89 Myxomatous valve, 65 N Native aortic annulus, 35 Near infrared spectrometry (NIRS), 118, 165 Neo-cords, 80 Nicks procedure, 35 Nicks Technique, 36 Non-coronary annulus, 31 O Octopus retractor, 10 Octopus®, 10, 11

181 Organ explant, 131 Orthotopic heart transplantation bi-atrial implantation technique, 145, 147 clinical outcomes, 147 de-airing and weaning, from CPB, 145 donor heart preparation, 142, 143 donor selection, 139 implantable left ventricular assist devices (LVADs), 147 implantation aortic anastomosis, 143, 144 IVC anastomosis, 144, 145 left atrial anastomosis, 143 pulmonary artery anastomosis, 143 SVC anastomosis, 145 preoperative preparation, 139 recipient preparation, 139, 141 timing of surgery, 139 P Papillary muscle rupture, 19 Papillary muscles, 20, 105 Paraplegia, 117 Parenchymal injury, 132, 137 Pericardial augmentation, 87 Pericardial reflections, 151 Pericardial stay sutures, 10 Pericardiectomy, 173, 176 Pleural cavity, 133 Pneumonectomy, 134 5-0 polypropylene sutures, 36 3-0 polypropylene traction sutures, 151 Posterior leaflet, 100 Posterior mitral valve annulus, 101 Posterior septal defect, 16 Posteromedial commissure, 100 Postinfarction anterior ventricular septal defect, 15–17 Postinfarction posterior ventricular septal defect, 17 Post-operatively careful medication, 176 Primary mitral regurgitation, 23 Primary tricuspid regurgitation, 24 Proximal anastomoses, 6, 7 Pulmonary artery, 151 Pulmonary artery anastomosis, 136, 143 Pulmonary artery trunk, 130 Pulmonary endarterectomy, 167 Pulmonary ligaments, 150 Pulmonary venous cuffs, 136 Q Quality of life, 147 R Rapid deployment valves, 50 Recipient chest cavity, 141 Recipient heart, 150 Recipient preparation, 146 Recipient right atrium (RA), 140 Rectangular pledgets, 45 Recurrent tricuspid regurgitation, 108 Recurrently laryngeal nerve palsy, 117 Residual atelectasis, 132 Retrograde perfusion, 132

182 Rheumatic mitral valve disease annular decalcification, 91 mitral valve reconstruction, 91, 93 surgical techniques, 89, 90 valve orientation, 90 valve replacement, 90 Rheumatic tricuspid valve, 114 Rheumatic valve disease, 89, 113 Right atrial anastomosis, 146 Right atriotomy, 113 Right coronary artery, 107, 113 Right femoral artery, 58 Right pulmonary artery, 121 Right ventricular muscular free wall, 105 Robotic mitral valve surgery, 62 S Scored pericardium, 178 Secondary mitral Regurgitation, 23 Secondary tricuspid Regurgitation, 24 Seldinger technique, 58 Sequential grafting, 7, 8 Severe mitral annular calcification, 84 Severe mitral regurgitation, 97 SEXI techniques, 4 Sinotubular junction (STJ), 44 Sliding annuloplasty, 70, 72, 73 St Judes Medical Valve Sizer, 45 Standard left atriotomy, 57 Staphylococccus epidermidis, 95 Staphylococcus aureus, 95 Stented bioprosthesis, 31 Sternotomy, 153 Streptococcus viridans, 95 Stroke, 117 Sub valve repair techniques, 112 Subannular suture, 45 Subsegmental disease, 167 Subvalvular structures, 98 Superior vena cava, 58 Superior vena caval anastomosis, 145 Surgical incision, 55–57 Swan-Ganz catheter, 118 Systemic embolisation, 98 Systolic pulmonary artery pressure (SPAP), 23

Index Temporary pacing wires, 52 Tendinous cords, 105 Tracheal anastomosis, 152 Transesophageal echocardiography, 33 Transient bacteremia, 95 Transoesophageal echocardiographic assessment, 47–48 Trans-oesophageal echocardiographic images, 95 Transoesophageal echocardiography, 145 Transverse aortotomy incision, 27, 33 Trapezoidal resection, 79 Triangular resection, 72 Tricuspid annular dilatation, 108 Tricuspid regurgitation, 24, 106, 107 Tricuspid valve, 106, 113 Tricuspid valve bioprosthesis, 113, 114 Tricuspid valve disease techniques annuloplasty band, insertion of, 107 anterior leaflet augmentation with pericardium, 111 clover leaf stitch, 109 de Vega annuloplasty, 108 inferior leaflet imbrication stitch, 110 sub valve repair techniques, 112 Tricuspid valve replacement, 114 U Urinary catheter, 118 V Vagus nerves, 150 Valsalva graft, 45 Valve exposure, 66 Valve orientation, 90 Valve preservation, 43 Valve repair, 46 Valve replacement, 86, 114 Valve Sparing Aortic Root Replacement (VSARR), 43 Vascular graft, 119 Venous cannulae, 56 Ventricular chamber, 13 Ventricular free wall rupture, 13, 18 Ventricular septal defect, 13–15 Vital adjacent neurovascular structures, 117 Y Y technique, 35, 42

T 2 4/0 Teflon Prolene sutures, 51