In Conversation With ... Professor David Wheatley
Professor Jeremy Pearson returns, virtually, to Scotland for the next in his 'In Conversation With...' series. In the summer of 2021, our Associate Medical Director spoke to former BHF Professor David Wheatley, who reflected on his extraordinary cross-continental research journey, learning from and working alongside early heart surgery pioneers, introducing heart transplantation to Scotland, and patenting his namesake heart valve in June this year.
Professor Wheatley was the BHF Chair of Cardiac Surgery at the University of Glasgow from 1979 – 2006.
Although the BHF subsequently appointed further surgical Chairs (the next was Ken Taylor at the Royal Postgraduate Medical School in 1983), in 1979 David was the only one. He was appointed to the endowed Chair following the early death of the BHF's first Professor of Cardiac Surgery, Philip Caves.
Caves, who died suddenly at the age of 38 while playing squash, had held the endowed BHF Chair for only 3 years. He trained with Norman Shumway, the US pioneer of heart transplantation, in Stanford. Caves was already a flourishing academic clinician with highly cited publications from his brief period as a BHF professor, on cardiopulmonary bypass, heart transplantation and rejection. In the USA he initiated the technique of endomyocardial biopsy, with a specifically designed surgical instrument to acquire endomyocardial tissue – known as the Caves bioptome and used in modified forms to this day. And in his short time in Glasgow he supervised the start of Ken Taylor’s career.
So David had a hard act to follow in Glasgow. From our conversation it’s clear he succeeded, but I first asked him about his life before then...
'David was born in England during World War II but emigrated in 1948 with his parents to South Africa, at the age of 6. This move turned out to be the event that shaped his career, because after high school in Cape Town (where he first thought he might become an engineer in future) he gained a place at the Cape Town Medical School – and incidentally a South African accent that is still subtly detectable. Here he had the single indelible experience that set him on the path to cardiac surgery. As a student in 1963 David was privileged to stand at the head of the operating table while Christiaan Barnard replaced a diseased aortic valve with a prosthetic valve of his own design, explaining each step of the surgery. Barnard, now known to the world as a brilliant and charismatic surgeon who carried out the world’s first heart transplant in 1967, was already a gifted and inspiring figure pioneering the new techniques of cardiopulmonary bypass as well as valve replacement. The first commercial valve, made by Edwards, was inserted in a patient in 1960. One of Barnard’s early “home-made” valves lasted 27 years in a patient before it was replaced.
The working conditions as a trainee surgeon at Groote Schuur Hospital were harsh, with clinical demand requiring the limited numbers of staff frequently to work for continuous 30-36 hour shifts and a total working week of up to 90 hours. In addition, the oppressive nature of apartheid, anathema to most medics, was increasing. There was a steady drain of medical expertise as the authorities clamped down on dissident views. One of David’s teachers, Raymond (Bill) Hoffenberg was told to leave and not come back. South Africa’s loss was the UK’s gain. Hoffenberg became Professor of Medicine in Birmingham, later President of the Royal College of Physicians and knighted in 1984 for his services to medicine. He was also President of the BHF Council (Trustee Board) in the 1980s.
David married in 1964, the year he qualified, and life in the USA (this was the time of President Kennedy and the early space race) seemed highly attractive. He and his wife travelled to the USA via England, visiting relatives and friends, which in turn sowed thoughts of a long-term future in the UK. After a profitable and enjoyable year as a surgical resident in Connecticut, with a growing interest in cardiac surgery, his decision to come back to the UK was hastened by the threat of being drafted in the Medical Corps to Vietnam, where the American involvement in the war was rapidly escalating.
David continued surgical training in London at the Royal College of Surgeons and then St George’s Hospital. He sought advice about his next career move from Donald Ross at the National Heart Hospital. Ross was then the pre-eminent cardiac surgeon in the UK, now famous for the Ross procedure where the patient’s diseased aortic valve is replaced with their own pulmonary valve which in turn is replaced with an allografted valve. Ross also led the team that carried out the first UK heart transplant in 1968, six months after Barnard, though the patient only survived for 46 days (Barnard’s patient survived for 18 days). Ross was an emigré South African and had been a fellow student with Christiaan Barnard. He strongly recommended that David should return to South Africa, but to Durban where Ben le Roux was pioneering cardiothoracic surgery. David said that the two years he spent in this world-leading department involved a very steep learning curve but were immensely rewarding. He came back to London where Donald Ross took him on as a senior registrar and it was at this time that David’s interest in research, particularly in heart valve replacement, was kindled.
The transition to academia began in 1973 when David moved to Glasgow, where he established a homograft heart valve bank and gained a ChM degree involving preclinical experimental studies to clarify and optimise the surgical techniques needed for heart valve replacement. Here in addition, thanks to a highly supportive department head (Bert Barclay), David was able to travel abroad frequently to see international experts. His love of travel persisted throughout his career.
In 1975 Philip Caves, back from the USA and a senior lecturer in Edinburgh, was appointed to the new BHF Chair in Glasgow – while David competed successfully for Caves’ post in Edinburgh! Further experimental surgical research in Edinburgh, on coronary artery obstruction, led to David gaining an MD from his alma mater, Cape Town.
With Philip Caves’ untimely death in 1978 David’s track record made him a strong candidate for the BHF Chair, which he then held until his retirement 28 years later, turning down the opportunity offered at the same time by Professor Stuart Saunders (Vice Chancellor) to return to Cape Town as Christiaan Barnard’s successor. David arrived in Glasgow to lead a department with a heavy clinical load in both paediatric and adult cardiac surgery. David’s energetic travels paid dividends in helping him to modernise and expand the department. A series of eminent colleagues contributed to a textbook in 1986 that David edited on the rapidly progressing field of coronary artery surgery. The foreword written by Denton Cooley of the Texas Heart Institute, another luminary of cardiac surgery, recognised David as a “skilled and talented surgeon” who had organised “one of the most outstanding cardiovascular programs in the UK”. There was also the potential to set up a heart transplantation centre in Glasgow: when David arrived in 1978 Terence English had just restarted heart transplantation in the UK at Papworth Hospital after an effective moratorium in much of the world following the disappointing experience in the late 1960s. However, David realised this would be a step too far at that time, though in 1990 he did introduce heart transplantation in Scotland, creating a centre modelled on the successful Stanford department led by Norman Shumway and with Shumway’s strong personal support. David was the lead surgeon for the first heart transplant operation in Scotland and ultimately led more than 20 further heart transplant operations.
David recalls that his personal acquaintance with Cooley and Shumway not only provided wonderful support for his own leadership but came with some reflected glory. Standing in line with other delegates to check in to the hotel for the American Association for Cardiothoracic Surgery conference, both Cooley and Shumway passed by within a few minutes of each other and greeted David enthusiastically. There was then a tap on David’s shoulder from the man behind him, and a bemused (and envious) Texas surgeon, who had never conversed with Cooley or Shumway but recognised their huge reputations, simply said “Who the hell are you?”
By recruiting two paediatric cardiac surgeons in Glasgow David was able to reduce his own clinical load, and he later recruited two transplant surgeons, one initially supported as a senior lecturer on his BHF Chair. So by good management David managed to reach a workable balance that allowed him to devote time to his research.
The core of David’s research programme throughout his tenure as the BHF chairholder was the design, construction, testing and clinical application of improved heart valves. Research in this field is challenging and needs stamina. Even nowadays, when computational flow and strain analysis can provide a more focussed theoretical starting point for valve design, in vitro testing of prototypes to confirm mechanical durability and compatibility with blood perfusion under realistic flow conditions takes around 2 years, while testing in animals (which can run at least in part in parallel) takes around 3 years. All this before the first clinical safety and efficacy trials can begin, and with no certainty of long-term success. And in a field that is still seeking optimal solutions, having ranged from mechanical valves to prosthetic valves using human or animal tissue, and to valves with leaflets constructed from synthetic non-thrombogenic materials.
David has been intimately involved with all of these challenges. One of his highest cited papers, in the New England Journal of Medicine in 1991, reported on the long-term comparison between a mechanical valve (the Bjork-Shiley valve) and a prosthetic valve with leaflets from porcine pericardium, from the Edinburgh Heart Valve trial he helped to set up in 1975. Survival after 5 years was equivalent, but after 12 years survival without re-operation was superior for the mechanical valve – though this was associated with an increased risk of bleeding due to the need for anticoagulant treatment. In Glasgow David designed an improved prosthetic pericardial valve that succeeded in preclinical testing and got as far as a clinical trial, though this was then halted because of concerns about long-term safety: the valve leaflets were from bovine pericardium and the potential for BSE to transmit to humans was being recognised. Together with poor suitability of either prosthetic or mechanical valves for many younger patients around the world (often with rheumatic heart disease), the withdrawal of the bovine prosthetic valve re-energised David’s attempts to design a synthetic valve that could combine long life and low thrombogenicity.
As lead investigator in collaboration with partners at the Universities of Leeds and Liverpool (Professor John Fisher, a former colleague of David’s in Glasgow, and Professor David Williams, both bioengineers) David developed a novel synthetic heart valve with leaflets of polyurethane. In the 1990s they developed the valve design, selected optimal variants of the polyurethane for the leaflets, manufactured valves and tested them in vitro and in animals, studying durability and function and confirming their low thrombogenicity and resistance to calcification. In 1996 the leading design was taken up by Aortech, a Scottish heart valve manufacturer, gained FDA approval and reached early clinical trials in the USA, with high hopes. Aortech expected to create many new jobs and as the Scottish Herald trumpeted “If they find the holy grail of heart valves, they could sweep the board in a world market estimated at 400 million patients”. Alas, the trials failed. In retrospect it became clear that the quality of the commercialised leaflets was lower than David’s prototypes, and the valves only received regulatory approval for use in left heart assist devices (which are not intended to have a long life).
Undaunted and convinced that in principle a polyurethane valve could be superior to others, David has continued to refine and improve the design of these valves. To this day, long after his official retirement, he collaborates with mathematicians, tissue engineers and injection moulding companies and has recently patented the Wheatley Valve with a novel leaflet design intended to interact favourably with flow patterns in the ascending aorta. Others around the world are experimenting with polyurethane valves modified to enhance durability or to promote endothelial cell coverage for natural biocompatibility. The first feasibility study of a biostable polyurethane aortic valve prosthesis commenced in 2019 in the USA, but the holy grail of heart valves is still awaited.
David was an ambassador and champion for academic cardiothoracic surgery throughout his time in Glasgow. He was one of the ten founder members of the European Association for Cardiothoracic Surgery in 1986, now with over 4000 members and providing accreditation examinations that David was instrumental in organising, and he was president of the UK Society from 1996 to 1998. As a Council member of the Royal College of Surgeons in Edinburgh for a total of 15 years David set up specialty exams for overseas centres (involving more global travel!) and he was the first chairman of the UK’s intercollegiate examination board in cardiothoracic surgery. He found teaching rewarding; he also trained a series of highly successful academic cardiothoracic surgeons including David Taggart (now Professor in Oxford), Tom Spyt (Professor in Leicester, now retired) and John Dark (Professor in Newcastle).
I asked David Taggart for any reflections he had on his time in Glasgow and his overwhelming memory was of David as a fair but firm boss – highly supportive but in return expecting the highest standards for research or clinical work. When things went well David made his praise clear, but he could equally make his displeasure clear if they didn’t! David’s stories about his wide set of national and international colleagues enthralled Taggart as a trainee and helped to stimulate his own future ambitions. John Dark also recalls David’s strong support for his trainees, in his case whether (reminiscent of David’s own early experience with Christiaan Barnard) taking him through John’s first aortic valve replacement or in due course unobtrusively influencing his appointment to a consultant post in Edinburgh.
Thanks to a friendship formed with the pre-eminent Egyptian cardiac surgeon, Dr Ismail Sallam, who went on to become the Minister of Health from 1996 to 2002, David had trainees in Glasgow from Egypt and regularly visited Cairo to train surgeons there. Sitting next to the Minister at a formal banquet the entertainment included a belly dancer. She paid her respects to Dr Sallam, who introduced David to her as a visiting heart surgeon from Scotland. Her response was to take David’s hand and clasp it to her voluminous breast saying “Feel my heart!”. On return to Glasgow a nurse enquired how David’s trip to Cairo had gone. He related the tale of the belly dancer, to get the instant quip in reply “Gee Professor, lucky you’re not a gynaecologist!”.
I asked David about his activities in retirement. He has not moved from the house near Glasgow he bought soon after he arrived there. Our Zoom meeting revealed a study replete with books and memorabilia, working models of heart valves, and a magnificent wooden scale model ship (Sovereign of the Seas, a famous 17th century English warship) imported from South Africa. When not engaged with his continuing profitable academic collaborations, he plays the piano – having first played jazz as a young man he then studied classical music. David is also a man of faith, regularly attending the local church, and is currently occupying some of his time (and intellect) by reading for a degree in theology. As for exercise, nothing too strenuous now, though he did take up cycling for a few years after retirement. While this kept him fit, he found it began to lead to episodes of postural hypotension – slightly alarming. However, a thorough check up by Stuart Cobbe (former BHF Walton Professor of Cardiology) and his team pronounced that there was nothing detectably amiss with David’s cardiovascular system and that cycling had perhaps just made him “too fit”?
We concluded our conversation with David’s appreciation of the BHF Chair, without which he felt his research career and his professional contributions nationally and internationally to his specialty would simply not have been possible. BHF support to fund key research staff was crucial. The independence the BHF Chair afforded made it possible to travel to international centres of excellence to expand his knowledge and build up the many links he had with leaders in cardiothoracic surgery across the world. David finally paid tribute to all the support he has received from many Scottish colleagues and noted with some pride (showing me the trophy) that he had the honour to be voted “Scot of the Year” by the Glasgow Daily Record in 1992 – despite being an Englishman with a South African accent'.