Prolonged Hypothermic Cardiac Storage with Histidine-tryptophan-ketoglutarate Solution-Comparison with Glucose-insulin-potassium and University of Wisconsin Solutions

Abstract

95 This study was designed to test the efficacy of histidine-tryptophan-ketoglutarate (HTK) solution after prolonged cold storage as compared with the conventional glucose-insulin-potassium (GIK) and University of Wisconsin (UW) solutions. Methods. (1). The hearts isolated from male Wistar rats were divided into three groups (n=6 per group) according to each preservation solution used. The hearts were arrested and stored in each solution for 6, 8, and 12 hrs at 4 °C. After storage, recovery of cardiac function and myocardial adenylate and water contents were evaluated. (2). Mechanical function of the epicardial coronary arteries (left main trunks) were compared between UW and HTK solutions. Coronary vascular responsiveness were examined at four predetermined time points: prior to flush and following flush, storage, and reperfusion. Results. (1). Cardiac function, which was sufficiently maintained in the HTK group up till 8 hrs of storage decreased below 50% following 8 hrs of storage in the UW and GIK groups. Although the myocardial ATP/ADP ratio in the HTK group was maintained above 50% up till 8 hrs of storage, those ratios in the GIK and UW groups declined to 15%. The values of myocardial energy charge in the HTK group were maintained above 60% up till 8 hrs of storage, however, those values in the UW and GIK groups declined to below 50% following 6 hrs of storage. The water contents following 12 hrs of storage were lower in the HTK and UW groups than in the GIK group. (2). Following reperfusion, the maximal relaxation response to acetylcholine in the HTK group was higher than in the UW group (p<0.05), and the endothelium-independent relaxation response to sodium nitroprusside in the HTK group was also well preserved. Discussion and Conclusion. In comparison with UW and GIK solutions, HTK solution, which sustains myocardial energy level and coronary artery function during preservation may lead to a better recovery of cardiac function; however, successful cold storage of the heart is highly energy-dependent, and a dramatic breakdown of myocardial energy level, which causes a crucial decline in the cardiac function, occurs between 8 and 12 hr of storage.