Heart transplantation

Professor John Dark, Freeman Hospital, Newcastle upon Tyne

Although it is more than 40 years since the first heart transplant, famously performed by Christian Barnard in South Africa, there was very little real success until the early 1980s.  Pioneering transplant programmes established by Sir Terence English and Sir Magdi Yacoub at Papworth and Harefield Hospitals respectively led the way.  By the end of the 1980s a number of centres around the UK were officially designated.  Heart transplantation is a very specialised activity, carried out in relatively small numbers, and is best done by highly trained and very focussed teams.  For this reason it has always been kept under central control and designation by the Department of Health and is currently one of the responsibilities of the National Commissioning Group (NCG).

TRANSPLANT CENTRES

Heart transplantation is carried out on a number of sites around the country.  These are

Papworth Hospital, Cambridge
Harefield Hospital, London
Freeman Hospital, Newcastle upon Tyne
Wythenshawe Hospital, Manchester
Queen Elizabeth Hospital, Birmingham
Golden Jubilee Hospital, Glasgow

There are two centres dedicated to the treatment of children requiring heart transplants, at Great Ormond Street in London and the Freeman Hospital in Newcastle upon Tyne

WHO NEEDS A HEART TRANSPLANT?

Many patients with heart failure can be very well treated with drugs and occasionally surgery.  Heart failure is often the result of coronary artery disease, and often follows a number of heart attacks but can also be due to direct failure of the heart muscle, so called cardiomyopathy.  Roughly equal numbers of transplants are performed for these two conditions.  In children about half the transplants are needed for cardiomyopathy and the other half for inborn abnormalities of the heart, so called congenital heart disease.  

For some patients the disease progresses to a point where the function of the heart can no longer be supported by drugs and a heart transplant is required.  Because the number of transplants performed is very limited (see below) only the most seriously ill patients can be treated.  Patients are only accepted by transplant if they are likely to die without the operation and if they are otherwise fit enough to survive the rigours of a very major surgical procedure.  Most heart transplants in the UK are performed in patients in hospital, usually receiving infusions of drugs to support the heart and increasingly being kept alive with a temporary mechanical pump (see below).  


HOW AM I REFERRED FOR A HEART TRANSPLANT?

Patients with heart failure are looked after by cardiologists and often specialised heart failure nurses at hospitals around the country.  Many of these will have a link with the nearest heart transplant centre.  If the cardiologist feels that you might be a candidate for a heart transplant you would be referred for a period of assessment.  A multidisciplinary team of cardiologists, surgeons, co-ordinators, social workers and specialist nurses will decide if there is any alternative to transplant, and if not whether the potential benefits are worth the high risk of transplantation.  Patients are placed on a waiting list for transplant but in practice only the sickest have a good chance of receiving organs and they are often waiting in hospital.


WHAT HAPPENS DURING A TRANSPLANT?

When a suitable heart from an organ donor becomes available it is allocated to an appropriate recipient on the basis of size and blood group.  About a third of the hearts transplanted in the UK go into a centrally run urgent offering system to ensure that the very sickest patients around the whole country receive the highest priority.  This allocation is organised by NHSBT. A similar service is run for very sick babies and children.

A series of precise measurements are made on the function of the donor’s heart.  If it is suitable it will be removed and stored on ice and transported rapidly to the transplant centre.  In the meanwhile the potential recipient is anaesthetised and his or her chest is opened.  Once the new heart arrives, the recipient’s heart is removed.  The patient is  kept alive in the meanwhile by the use of a heart lung machine.  The new heart is rapidly sewn into position in the chest as no more than 4 hours can elapse between the time the heart is removed from the donor and the time it receives a new blood supply in the recipient.  With its new blood supply the heart restarts and in due course takes over the circulation.  At the end of the operation the patient is transferred to the intensive care unit and will often stay there for several days before moving on to one of the surgical wards.  Most patients will spend 2 or 3 weeks in hospital after their transplant.

Drugs to suppress the body’s immune system are started immediately and the heart is monitored very closely for signs of rejection.  In the modern era life threatening rejection is  unusual.  Patients can be rehabilitated very rapidly and return to a completely normal level of activity.  Patients with transplant have taken part in competitive sports, run marathons and climbed mountains.  Many are fit to return to work.

WHAT ARE THE RISKS OF A HEART TRANSPLANT?

Many patients undergoing heart transplant are desperately sick but nevertheless 85-90% of them will survive the period after the transplant and for at least a year.  Failure of the new heart to function well immediately after the transplant is the commonest cause of early death and occurs in 5-10% of patients.  It probably represents damage to or disease of the heart that had already occurred in the donor.  There is a constant although small risk of rejection and a risk of infection in patients who have the natural functions of the immune system suppressed by drugs.

The drugs continue life long and it is important to continue to monitor the heart very closely.  

The biggest problem as the years go by after a transplant is narrowing of the arteries of the transplanted heart.  This occurs because the lining of these arteries represents the “frontier” between the donor’s tissue and the blood of the recipient.  There is thus the potential for continuing damage and eventually narrowing of these arteries.  Nevertheless about 75% of patients survive 5 years after a transplant and more than 50% will be alive after 10 years.  A number of patients have survived 20 or even 25 years after a heart transplant.  Particularly for younger patients, if the new heart fails there is the prospect of a repeat or re-transplant.


HEART TRANSPLANT ACTIVITY IN THE UK

In the mid 1990s there were over 250 heart transplants a year in the UK.  The number fell in the late 1990s and early years of this century and has now stabilised at around 120 adult transplants and about another 30 paediatric (ie under 16) transplants per year.  The main reason for this fall is that increasing numbers of hearts from potential organ donors are already diseased, particularly as the average age of donors rises.  It is hoped that new initiatives to increase the number of donor hearts will have a positive effect on the number of heart transplants.  

All the centres in the UK take part in the Thoracic Transplant Audit, run by the Clinical Effectiveness Unit at the Royal College of Surgeons.  The results of centres are monitored very carefully and an annual report made to the National Commissioning Group.  The UK also provides data to the International Society for Heart and Lung Transplantation which compiles an international registry. 

WHAT IS NEW IN HEART TRANSPLANTATION?

Many patients with advanced heart failure are so sick they are at a risk of dying unless they can have a heart transplant.  Unfortunately the right heart may not become available at the right time.  There is increasing use of mechanical pumps, often termed left ventricular assist devices or LVADs, that keep patients alive until they can be transplanted.  These pumps have been used in adults for a number of years but now are increasingly used also in children.  They may lie outside the body connected to an external compressed air driver but increasingly they are placed inside the body with only an electric cable coming out through the skin.  Patients can be sent home with these pumps and have even returned to work.  There remains risk of infection and blood clot forming on the pump.  For the moment none of the pumps available are as good as a heart transplant.  In the UK the National Commissioning Group (NCG) are responsible for funding the use of these pumps as a so called bridge to transplant at three centres – Papworth, Harefield and Freeman Hospitals.  It is planned to extend this service to the other heart transplant centres in the UK.  In the fullness of time, as these pumps become perfected, it is likely that they will replace the need for heart transplant for many patients.  Already we see desperately ill patients kept alive and indeed made much healthier with the use of a pump, whilst they wait for a transplant.