Orthotopic transplantation of the pig heart.

Orthotopic transplantation of the pig heart is described, with success in the last 12 of 23 studies, leading to survival until rejection in the last two. The pig heart was found to be easily damaged by cold. In contrast, organ viability was not appreciably affected when the warm ischaemic time was shortened by making the aortic anastomosis the initial manœuvre of implantation. The advantages of the pig as a model for the study of orthotopic cardiac allografts would appear to be its tolerance of long periods of cardiopulmonary bypass, immediate clotting after heparin reversal and ability to maintain the circulation without drug or pacemaker support. These factors have contributed to the relative simplicity of post-operative management.