Surgeons develop 2 ways to ‘restart’ hearts without a donor’s body

Cardiac surgeons have discovered two novel techniques that may improve doctors’ ability to “reanimate” hearts after the death of a donor. In one procedure, which successfully saved the life of a 3-month-old child transplant recipient, oxygenated blood is pumped into an extracted heart while it rests on a surgical table, eventually causing it to “wake up” and beat again. The other technique involves flushing a cold solution of liquid and preservatives into a heart before surgeons remove it from the donor’s body. Both methods could potentially open up new, cost-effective approaches for recovering viable hearts from donors who have been declared dead.

Researchers involved in the procedures say that increased supply of usable hearts could lead to 100 more pediatric heart transplants per year in the U.S. alone. That would make a significant difference: an estimated 500 children in the U.S. die each year while waiting for a new heart. The procedures, conducted by surgeons from Duke and Vanbeliet University, were outlined in a pair of papers published this week in the New England Journal of Medicine (NEJM).

How to ethically “restart” a heart

Successfully transplanting any organ is a complex procedure, but heart transplants are among the most challenging. Most hearts currently used in transplants come from donors who are declared brain dead but whose hearts are still beating. But there are far more people who need heart transplants than donors who fit that criteria. 

In 2020, researchers at NYU Langone attempted to address this shortage using an experimental technique called normothermic regional perfusion (NRP) on a patient whose family had withdrawn life support. That patient’s heart fell under a category doctors refer to as donation after circulator death (DCD). In this case, doctors used a machine to pump oxygenated blood back into the heart while it was still in the deceased patient’s body. The process succeeded, reanimating the heart and allowing it to be used in a transplant.

But while NRP has been shown to work in some cases, it has drawn scrutiny from ethicists and policy makers who fear the practice of reanimating a heart in a deceased person risks muddying the definition of death. Some hospitals actively prohibit doctors from performing NRP operations and the American College of Physicians (ACP) even released an official statement of concern saying the practice “raises ethical questions and concerns.” Other medical professionals have called it “creepy.” 

The new approaches outlined in (NEJM) this week attempt to side-step those ethical concerns in two unique ways.

The first procedure, performed by surgeons at Duke University, involved removing the tiny heart of a 1-month-old infant donor. It was then operated on outside the body on a surgical table. The process, completed in just under six minutes, involved pumping blood through a tube attached to the aorta. The blood was then drained from the heart via a vent and collected in a bag. 

That collected blood was reoxygenated and pumped back in. As soon as the heart began beating, the doctors placed it in cold static storage. From there, it was rushed to a transplant center, where it was successfully implanted into a 3-month-old recipient just around two hours later. That child, who is still living with the reanimated heart, was discharged from the hospital two months after the procedure. The heart, meanwhile, so far shows no signs of rejection or failure.

The second procedure aimed to address the challenge of using DCD hearts by preserving them with extreme cold. In this case, surgeons at Vanderbilt immediately filled the aorta of a deceased donor’s heart with an oxygenated fluid designed to keep it in a relaxed state. According to the paper, the fluid consists of a mixture of red blood cells, electrolytes, vitamins, and a cold preservative solution. These nutrients help replenish what may be lost during the “dying process” and protects the heart during transport. Unlike the first procedure, cold preservation here allows surgeons to transplant the donor heart into the recipient without ever needing to restart its function beforehand.

“We’re not reanimating the heart,” Vanderbilt University Medical Center cardiac surgeon Aaron Williams said in an interview with Science. “We’re resuscitating it.” 

Researchers involved in both studies say the new techniques may improve surgeons’ ability to successfully transplant hearts from DCD donors—without having to navigate the ethical complexities of reanimating the organ while still in the donor’s body. Though both procedures are still relatively nascent, Joseph Turek, one of the cardiac surgeons involved in the research from Duke, told Science he is optimistic the combined procedures could increase the pediatric heart transplant donor pool by up to 20 percent. 

 

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