Duke University Doctors Re-Animate a Heart. What Does it Mean for Modern Medicine?
Earlier this month, doctors at Duke University were able to transplant a “reanimated” heart into a human adult patient. The procedure had been performed before on pediatric patients, but this is the first adult transplant in the United States. Australia and the UK have been performing the same procedure for several years, which Dr. Pedro Catarino, director of transplantation at Royal Papworth Hospital in the UK, suggests is because there was less of a desperate need in the United States. That allowed doctors to wait and see the results of the transplants up to four years after the procedures occurred.
The reanimation and transplant procedure is called “donation after circulatory death,” and it involves transplanting a heart that has been reanimated after it stops beating. This is opposed to the normal heart transplant method, where a still-beating heart is transferred from the donor to the recipient. This is achieved by means of a special pump.
Obviously, this new technology and procedure will have an impact on the practice of medicine in the United States. Read on to find out the implications for heart transplants and the waiting list in the United States.
How doctors achieved the reanimation
The reanimation was made possible by the TransMedics Organ Care warm perfusion pump. A perfusion pump is the type of pump that doctors use to pump blood through body tissue while a surgeon operates. Duke University is one of five medical centers in the country that has FDA approval to operate a TransMedics clinical trial.
The pump allows doctors to preserve and reanimate hearts for donation after they’ve stopped beating. In this Duke University transplant, the donor’s heart was allowed to stop for five minutes after circulation stopped. At that point, the doctors removed the heart and other organs for donation.
The heart was then pumped through with a cold solution that would allow the heart to be preserved in between donation and transplant. Afterwards, the heart was placed into the TransMedics organ care pump, which suffused it with blood until it was beating on its own again.
Some doctors find the risk to outweigh the rewards, however, due to the fact that there’s no way to be certain just how much the lack of blood and oxygen has affected the tissue between death and the cold solution. Only later on down the line, when the heart has already been transplanted, will issues arise. For some, that’s a risk too serious to take.
Because the DCD procedure is relatively new in the United States, there’s insufficient data regarding survival rates. Currently, the median survival rate after non-DCD transplants is 13 years.
Some doctors believe that a DCD heart will allow for better donor/patient matches, thanks to the increased time between death and transplant. They also believe that it will vastly increase the donor pool. While 250 million Americans qualify for heart transplants each year, only about 10% of that number actually undergo transplants, due to the lack of appropriate donor hearts for donation after brain death. Researchers suggest the relative lack of donor hearts is due to “improved road safety, continued low organ donation rates and increasingly older donors with multiple co-morbidities.”
The history of the modern heart transplant
The first human heart transplant in the United States was performed in 1967 by Christopher Barnard. Prior to that, surgeons had experimented with heart transplants on animals for centuries, noting their anatomical similarities. In some cases, animal organs have been used for human patients, although the success rate has been limited by tissue incompatibility and lack of immunosuppressants.
In addition to researching DCD, scientists continue to research the viability of artificial hearts as well as ventricular assist devices to bridge the gap between discovering the disease and when a donor heart is found. This is especially important, given the relative shortage of donation hearts currently available.
DCD’s impact in the future
While scientists estimate that a widespread usage of DCD could increase the donor pool up to 30%, others are skeptics. Dr. Ashish Shah, the chair of cardiac surgery at Vanderbilt University Medical Center, believes that it will have a limited impact, given that it will require greater facilities and additional training and expertise on the surgeons’ behalf. Logistically, we’d need to see greater changes in facilities on the whole, which takes time, but having more donor hearts available is never detrimental to patients or doctors.