Many surgeons gave up cardiac transplantation due to poor results, often due to rejection of the transplanted heart by the patient's immune system. Barnard persisted until the advent of ciclosporin, an effective immunosuppressive drug, which helped revive the operation throughout the world. He was also the first surgeon to attempt xenograft transplantation in a human patient, while attempting to save the life of a young girl unable to leave artificial life support after a second aortic valve replacement.