The incidence of heart failure, where a patient’s heart is no longer functioning adequately to support a good quality of life is increasing rapidly and is the leading cause of death in the Western world. In the United Sates of America, it is estimated that 5.1 million people live with heart failure with an additional 825,000 diagnosed annually. In the United Kingdom (UK) too, thousands of patients are diagnosed annually with heart failure. Heart transplantation remains the most effective treatment for end-stage heart failure providing recipient patients with an excellent quality of life and a median survival approaching 11 years following their heart transplant. There has been a steady rise in the number of patients on the heart transplant waiting list with greater than a 2-fold increase from 2010 to 267 patients in 2015. In the UK, less than half of patients who are listed for a heart transplant will receive this life-saving treatment even after waiting for 3 years.
Donation after brain death
Until recently, donation after brain death (DBD) has been the sole source of donor hearts. These are patients who have sustained a severe brain injury and after extensive neurological testing, are shown to have no meaningful brain function. These patients are classified as “brain stem dead”. Once certified as brain stem dead, the donor is then taken to the operating room where the heart is assessed by a surgeon whilst it is still beating. Hearts that are deemed suitable for transplantation are then given a cold solution high in potassium to stop the heart and protect the heart before transporting it back to the recipient hospital in ice ready to be transplanted. However, due to increasing donor age and a greater burden of donor co-morbidities, a growing proportion of donor hearts are being declined for transplantation.
The decline in brain dead donors
There has been a decline in the number of hear transplants performed globally, and this is largely due to a decrease in the number of suitable donors who have sustained brain death. Currently, the leading cause for brain death is subarachnoid haemorrhage (spontaneous bleeding around the brain) and traumatic brain injury. Positive steps in medical technology and legislation, including the development of better treatment for patients following subarachnoid haemorrhage, advances in motor vehicle safety and more stringent penalties for speeding and driving under the influence of alcohol has led to a smaller number of people at risk of ending up in hospital in a position of being brain dead. What this also means is that there are fewer suitable donors for heart transplantation and we face the clinical reality that only the sickest of heart failure patients will be in a position to be offered a heart transplant and even fewer will actually receive one.
Increasing the number of heart transplants
In an effort to increase the number of possible heart transplants, strategies have been implemented to attempt to improve the function of donor hearts that previously may have been declined for transplantation. Transplant teams have also looked at broadening their acceptance criteria to include ‘higher risk’ or ‘extended criteria’ donor hearts given the desperate need for patients waiting for a heart transplant.
Non-heart beating donors or donation after circulatory death has provided a significant boost in the number of available organs to patients requiring kidney and liver transplants and now in the modern era, we are able to utilize hearts from DCD donors to provide more donor hearts in an attempt to meet the unmet need for patients with heart failure who wait patient patiently for a heart transplant.