Richard "Rick" Slayman, 62, had the transplant in March at Massachusetts General Hospital in the United States, with surgeons expressing optimism that the pig kidney would last at least two years. The Massachusetts General Hospital transplant team said in a statement that they were deeply saddened by Slayman's death and offered condolences to his family. The surgeons said they had no indication that Slayman died as a result of the transplant. "Rick" Slayman was the first living person to have the surgery. Pig kidneys had previously been transplanted into brain-dead organ donors, temporarily. Slayman had received a kidney transplant at the hospital in 2018, but he went back on dialysis last year when that kidney began to fail. When complications from dialysis left him needing frequent procedures, doctors suggested the pig kidney transplant. In a statement, Slayman's family thanked the doctors for "their extraordinary efforts" in performing the transplant that gave them "an additional seven weeks with Rick" and said "the memories created during that time will endure." The family said Slayman underwent the surgery in part to give hope to the thousands of people waiting for transplants who die each year. Xenotransplantation is the transplantation of cells, tissues or organs from one species to another. Such efforts have long failed because the human immune system quickly attacks foreign animal tissue, the AP reports, but recent attempts have involved pigs that have been genetically modified to make their organs more human-like. Read Also: "Transformer". Woman has world's first combined surgery in the USA (Portuguese version)