Pig-to-Human Heart Transplant Update

Lawrence Faucette, who had end-stage heart disease, received a genetically modified pig heart transplant at the University of Maryland Medical Center on Sept. 20, 2023.  He passed away on Monday, October 30, just six weeks after he received the xenotransplant.

He had been making progress after the surgery, going to physical therapy and spending time with family, but his body began to show signs of rejecting the heart in recent days. Rejection is common in transplants of human hearts, and the rejection in this case may or may not be due to the xenotransplant.  Researchers will be conducting tests to determine the cause of the rejection and to improve the survival of any future xenotransplant recipients.

Mr. Faucette, a Navy veteran, was the second recipient of a pig to human heart transplant at the University of Maryland Medical Center. The first patient to receive a modified pig heart transplant was David Bennett Sr., who officials said did not reject the heart but died of heart failure two months after the procedure.  Last month, Bennett’s transplant surgeon revealed that the pig’s heart was infected with a porcine virus known as porcine cytomegalovirus, which may have contributed to Bennett’s death.

Despite worries that xenotransplantation could trigger a pandemic if a virus were to adapt within a human body and spread to others, experts believe that the specific type of virus in Bennett’s donor heart is not capable of infecting human cells.

According to Jay Fishman, a specialist in transplant infections at Massachusetts General hospital, there is “no real risk to humans” of it spreading to others. Rather, the concern stems from the ability of porcine cytomegalovirus to trigger reactions that can damage and destroy not only the organ, but also the patient.

Shortly after Bennett’s surgery, his team frequently monitored his recovery through various blood tests. In one of the tests, doctors examined Bennett’s blood for traces of various viruses and bacteria and found “a little blip” that indicated the presence of porcine cytomegalovirus. However, because its levels were so low, the doctors assumed that the result could have been an error.

Because the special blood test for the porcine cytomegalovirus took approximately 10 days to carry out, doctors were unable to know that the virus was already beginning to multiply rapidly. As a result, this may have triggered a reaction that was likely “cytokine explosion,” a storm of exaggerated immune response that can cause serious issues.

When surgeons performed the transplant on Mr. Faucette, the second xenotransplantation recipient, they tested the pig heart for the porcine cytomegalovirus prior to use, but the graft eventually failed from what appears to be acute rejection.  Further tests are pending.

These two brave pioneers gave their lives in service to their fellow humans, hoping to pave the way for future patients who need heart transplants.  Their selfless act may someday reduce or even eliminate the number of people who die while waiting for an organ transplant.