Low-Flow Hypothermic Crystalloid Perfusion Is Superior to Cold Storage During Prolonged Heart Preservation

Background. Preservation of donor hearts for transplantation has traditionally been performed with the use of static cold storage. We have developed and tested a novel gravity-powered system of cold crystalloid perfusion for prolonged donor heart preservation. Methods. Greyhounds were anesthetized; their hearts were arrested with cold cardioplegic solution and excised. Hearts were allocated to 12 hours of perfusion preservation (n = 6) or cold storage in ice (n = 5). Non-preserved hearts (n = 5) served as a normal reference group. Perfusion hearts were perfused (20 mL/min, 8-12 degrees C) with a novel oxygenated nutrient-containing preservation solution. After preservation, the recovery of the hearts was assessed in a blood-perfused working heart rig over 2 hours in terms of function, blood lactate level, myocardial adenosine triphosphate, and histology. Results. After 2 hours of reperfusion, in comparison with cold storage hearts, perfused heart function curves showed superior recovery of cardiac output (P = .001), power (P = .001), and efficiency (0.046 +/- 0.01 vs 0.004 +/- 0.003 joules/mL O-2, P = .034). Myocardial adenosine triphosphate content (mmol/mg protein) was reduced significantly from the normal level of 26.5 (15.9, 55.8) to 5.08 (0.50, 10.4) (P = .049) in cold storage hearts but not in perfused hearts. Over a period of 2 hours, lactate levels in the blood perfusate were significantly lower in the perfusion group than in the cold storage group (P < .05). Conclusions. Continuous hypothermic crystalloid perfusion provides myocardial preservation superior to cold storage for long-term heart preservation, with potential applicability to marginal and donation after circulatory death hearts.