The first recipient of a modified pig kidney transplant died on Saturday, around two months after the surgery was carried out in the US's Boston.

The family members of 62-year-old Richard “Rick” Slayman and the Massachusetts General Hospital, where the procedure was performed, did not link the transplant surgery to his death.

“We have no indication that it (Slayman’s death) was the result of his recent transplant,” the hospital said in its statement.

His family also thanked doctors for their work and said: “Their enormous efforts leading to the xenotransplant gave our family seven more weeks with Rick…”

According to the US Food and Drug Administration (FDA), “Xenotransplantation is any procedure that involves the transplantation, implantation or infusion into a human recipient of either (a) live cells, tissues, or organs from a nonhuman animal source, or (b) human body fluids, cells, tissues or organs that have had ex vivo contact with live nonhuman animal cells, tissues or organs.”

It is the use of animal cells and organs to heal humans. Xenotransplantation involving the heart was first tried in humans in the 1980s.

The need for such a procedure was felt due to the significant gap between the number of transplantations needed by patients and the availability of donor organs.