The development of heart valve surgery
There have been dramatic changes in heart valve surgery in the past 60 years. We highlight some of the key developments, and Professor Ken Taylor (pictured), a retired cardiac surgeon who saw many of the changes throughout his career, gives his view.
The invention of the heart-lung machine - first used in 1953 - allowed the development of open-heart surgery. An important aspect of this was the treatment of defective valves, which has changed enormously in the last 60 years.
Open-heart surgery made it possible to repair the mitral and pulmonary valves with more precision, and also made it possible to tackle the aortic valve for the first time.
The first mechanical replacement valve was created and implanted by Albert Star and Lowell Edwards in America in 1960. As remains the case today, it meant that the patient would need to spend the rest of his life on anti-coagulant drugs to prevent blood clots forming on the valve.
It was the development of the heart-lung machine which really allowed cardiac surgery to develop
The first valve replacement from a human patient was first performed in 1962. Surgeon Alfred Gunning, from Oxford, had been using freeze-dried valves from donated corpses for his research. He gave some of these to Donald Ross, who was trying to repair an aortic valve when it disintegrated. Without many other options, Ross used one of the freeze-dried valves to replace it, and the patient did well.
With the help of BHF funding, Ross went on to improve surgical techniques and death rates dropped, he developed the Ross procedure, designed to treat patients with a faulty aortic valve. The procedure has two steps - the aortic valve is replaced with the patient's own pulmonary valve (this is known as an autograft). The pulmonary valve is then replaced with a valve from a corpse. The aortic valve is under the most pressure of all the valves, so the thinking is that the patient's own healthy pulmonary valve has the best chance of withstanding the pressure.
The procedure is still used today, and four in five patients live for at least another 20 years afterwards.
A cardiac surgeon's view
Professor Ken Taylor worked as a cardiac surgeon from the 1960s until his retirement in 2007. He was BHF Chair in Cardiac Surgery at Hammersmith Hospital from 1983 to 2007, and helped to set up the UK Valve Registry in 1986, which ran until 2007.
He says: “It was the development of the heart-lung machine which really allowed cardiac surgery to develop. There were a number of groups in the UK, Europe and America who were working on this with animal experiments at the same time, though it was in John Gibbon in Philadelphia who did the first successful heart-lung bypass in 1953.
“Three of his four patients died and he never did any more, but it took off very quickly. When I was a junior registrar opening a narrowed mitral valve – as John Fitzsimmins had in 1959 – was still one of the procedures being carried out. It was possible to do that without a heart-lung machine.
“The first mechanical mitral valve replacement was in 1960 – so John Fitzsimmins missed this possibility by just a year – and the first aortic valve followed a year later.
One of the big things that has changed is the age of patients being considered for valve replacement
“The 1960s was a time of huge development. As well as mechanical valves, homografts (valves taken from a human patient) and xenografts (using different species such as pigs) were being worked on.
The first mechanical valves were ball and cage valves. In 1969 a more advanced valve, a tilting disc valve, was developed, and in 1977 a bileaflet valve.
Although modern mechanical valves are more advanced, they still have the same issue as the earliest ones, requiring lifelong anticoagulant drugs to prevent blood clots. But they have the potential to last much longer, so one of the things we look at is how old the patient is and how long they might need the valve to last.
“One of the big things that has changed is the age of patients being considered for valve replacement. When I started as a consultant we rarely considered patients who were older than 70. Now it is common for older patients to have the surgery.
“We started the UK Valve Registry in 1986 to collect information on how many patients were having valve surgery, what kind of valves were being used, and how successful the procedures were. One of the things we were able to show is that with patients in their 80s and even early 90s who were fit, results were nearly as good as for patients in their 70s or younger.
“In recent years minimally invasive techniques have been developed, which allow aortic valve replacement without open-heart surgery, although many patients are still treated with conventional surgery.
“The BHF has done a lot to develop heart valve surgery. The BHF funded my first study, on the effects of heart-lung bypass during open heart surgery on inflammation in other parts of the body.”
Read how patient John Fitzsimmins has experienced valve surgery across more than 50 years
The BHF's role
The BHF started awarding its first research grants in 1962, and one was to develop techniques for implanting homograft valves. Donald Ross, one of the surgeons working on this, received several more BHF grants over the next 20 years, and developed the Ross Operation (see above), which is still used today.
Many more developments in valve surgery have been funded or supported by the BHF.