Heart failure, not rejection, to blame for death of first patient to receive pig heart

BALTIMORE — A new paper published by the doctors involved in a groundbreaking surgery to implant a modified pig’s heart into a human said that there were no signs of rejection when the patient died.

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David Bennett died approximately two months after the surgery at the University of Maryland Medical Center. At the time, there was no specific cause of death given, with doctors saying his health began to decline days before his death, as we reported at the time.

The heart functioned well for weeks after the initial surgery, and showed no signs of rejection when examined during Bennett’s autopsy, the University of Maryland Medical School said in a news release. Surgeons concluded based on the autopsy’s results that Bennett died of heart failure “likely caused by a complex array of factors.”

“Our findings on autopsy did not show evidence of rejection,” Dr. Bartley Griffith, the study’s co-leader, said in a statement. “Instead, we saw a thickening and later stiffening of the heart muscle leading to diastolic heart failure, which means the heart muscle was not able to relax and fill the heart with blood as it is supposed to.”

A virus had been detected in the pig’s heart after the surgery and was confirmed during the autopsy, NBC News reported. Whether that virus damaged the heart remains under investigation.

Bennett received the pig heart as a last-chance option to save his life in January 2022, WJZ reported. Bennett was not eligible for a human heart transplant and had been a patient at the hospital since October.

“We consider this to be an important learning experience,” Dr. Muhammad Mohiuddin, the study’s co-leader, said in a statement. “Knowing what we know now, we will alter some of our practices and techniques in the future.”