HTK VERSUS UW SOLUTION FOR MYOCARDIAL PROTECTION DURING MODERATE HYPOTHERMIA

The objective of this study was to assess the protective capacity of U W solution in comparison to Bretschneider's (HTK) cardioplegic solutio n under moderate hypothermic conditions (25 degrees C), as those usual ly present during intraoperative myocardial protection. Ischemia-induc ed alterations of cardiac function parameters were analyzed and compar ed for each solution after 45 min of ischemic storage and 60 min of re perfusion with oxygenated Krebs-Henseleit buffer (KHB), using a rat wo rking-heart model. Compared to nonischemic values, left-ventricular sy stolic and diastolic pressure, +dp/dt(max) and -dp/dt(max) were signif icantly better maintained in the HTK (95 mm Hg, 7 mm Hg, 2,657 mm Hg/s and 2,122 mm Hg/s) than in the UW group (76 mm Hg, p < 0.05, 11 mm Hg , p < 0.05, 1,745 mm Hg/s, p < 0.05 and 1,608 mm Hg/s, p < 0.05). Conc erning the myocardial contents of ATP, creatine phosphate and the ener gy charge, a minor decrease was observed after preservation in HTK com pared to UW solution. The results of this study indicate superior myoc ardial protection with the use of HTK solution for protection of the h eart at 25 degrees C compared to UW solution.