Light and electron microscopic evaluation of canine hearts orthotopically transplanted after 24 hours of extracorporeal preservation.

The hearts of 19 dogs were subjected to in vitro, moderately hypothermic, whole blood perfusion through the aorta for 24 hours. Sixteen of the hearts were reimplanted into recipient animals in the conventional orthotopic fashion and three were subjected to histologic study without reimplantation. Fourteen of the 16 reimplanted hearts successfully supported the recipients. Histologic and ultrastructural studies of the reimplanted hearts 24 hours and 7 days after implantation demonstrated good preservation of cellular and ultracellular structures. Some mild widening of the interstitium was noted.