Is profound hypothermia required for storage of cardiac allografts?

BACKGROUND Improved methods of cardiac allograft protection are required to expand the pool of potentially available organs and to enhance the recovery of grafts subjected to prolonged ischemia. We have previously demonstrated that limited coronary perfusion provided by donor blood harvested at the time of organ procurement can improve both metabolic and functional recovery after transplantation. In this study we evaluated the hypothesis that limited coronary perfusion may enable prolonged cardiac storage while avoiding the potentially detrimental effects of profound hypothermia. METHODS Fourteen orthotopic cardiac transplants were performed in female Yorkshire pigs by using donor blood perfusion during 5 hours of either tepid (25 degrees C) or cold (4 degrees C) storage. Assessments of myocardial metabolism and function were performed at baseline and after 45 minutes of normothermic (37 degrees C) reperfusion. RESULTS Hearts protected with tepid perfusion displayed improved recovery of myocardial function (89% +/- 18% vs 63% +/- 25%, P =.05). Diastolic compliance was adversely affected in both groups after transplantation. Aerobic myocardial metabolism was better preserved in the tepid group. CONCLUSIONS Profound hypothermia results in depressed myocardial metabolic and functional recovery after transplantation. Limited coronary perfusion with shed donor blood can permit cardiac allograft storage at tepid temperatures, resulting in improved myocardial performance.