A Maryland man who became the first person to receive a pig heart transplant has died two months after the groundbreaking, but highly risky, procedure. David Bennett Sr., 57, was initially said to be recovering well from the January operation but his doctors at the University of Maryland Medical Center had cautioned that “we don’t know what tomorrow will bring us. This has never been done before.” There was no obvious cause of death, the hospital told The New York Times on Wednesday. Dr. Bartley Griffith, who performed the transplant, said Bennett “proved to be a brave and noble patient who fought all the way to the end.” Bennett had undergone the seven-hour operation in a last-ditch effort to treat a life-threatening heart disease. “I know it’s a shot in the dark, but it’s my last choice,” he said in a statement issued a day before the operation.