Successful orthotopic canine heart transplantation after 24 hours of in vitro preservation

Abstract

A protocol was developed to provide continuous, hypothermic, low-pressure perfusion for 24 hours' preservation of the isolated canine heart prior to orthotopic transplantation. Donor cardiectomy included coronary vasodilatation with diltiazem, potassium arrest, and rapid cooling of the heart. The graft was perfused at a pressure of 18 to 22 cm H2O and at an average flow of 0.743 cc/min/gm of tissue. The septal temperature was 5 degrees to 7 degrees C and perfusate pH was 7.25 to 7.4. Two groups of mongrel dogs were studied after orthotopic transplantation: Group I (n = 15) received hearts perfused for 24 hours. Group II (n = 9) received hearts removed by the same cardiectomy technique, but transplanted immediately. All grafts were able to support the recipient circulation after cardiopulmonary bypass. These was no significant difference in survival or in graft function when hemodynamic studies were done in five animals of each group, between 5 and 10 days after operation. We conclude that a reliable and reproducible method of 24 hours' in vitro perfusion of the canine heart has been obtained and should be applicable in clinical cardiac transplantation when prolonged periods of preservation are required.