[The temperature dependency of the protective properties of the St. Thomas' Hospital cardioplegic solution, the University of Wisconsin solution, and Bretschneider buffered solution].

We studied three preservation solutions such as St. Thomas' hospital cardioplegic solution No. 2 (ST), the University of Wisconsin solution (UW) and Bretschneider's solution (BR) for protective properties, especially in terms of temperature dependence during the preservation. Rat hearts were studied and divided into three groups; ST. UW and BR. In each group, six hearts were carried out perfusion, cardioplegic infusion, ischemia and reperfusion for four different conditions. Using an isolated working rat heart model, the hearts were subjected to 5 minutes Langendorff perfusion followed by 20 minutes working perfusion. During this working period, cardiac functions such as aortic and coronary flow, aortic pressure, and heart rates were measured every 5 minutes. After working perfusion, 3 minutes of cardioplegic infusion was carried out either with UW, ST, and BR at 37, 20, 4, 1 degree C. The hearts were subjected to either 35 min at 37 degrees C, 120 min at 20 degrees C, 300 min at 4 degrees C, or 450 min at 1 degree C. The hearts were immersed in the same solution during ischemia. The hearts were reperfused at 37 degrees C, initially in the Langendorff mode for 15 min. Coronary effluent was collected for the measurement of CK leakage during reperfusion. The heart were then converted to the working mode for 20 minutes. During working reperfusion period, the variables of cardiac function were again measured and expressed as a percentage of their individual preischemic control values. Under conditions of 37 degrees C ischemia, % recovery of cardiac output (%CO) in ST group is 62.8 +/- 2.8%, although the hearts preserved with UW and BR were not recovered. Under conditions of 20 degrees C ischemia, %CO in UW, ST and BR were 46.8 +/- 2.7, 82.0 +/- 3.1 and 41.4 +/- 2.6%, respectively. Under conditions of 4 degrees C ischemia, %CO in UW, ST and BR were 66.2 +/- 8.0, 68.6 +/- 2.3 and 47.2 +/- 2.9%, respectively. Under conditions of 1 degrees C ischemia, %CO in UW, ST and BR were 70.6 +/- 3.3, 56.5 +/- 1.6 and 43.0 +/- 2.5%, respectively. In conclusions, ST revealed the best protective properties for the heart preservation between 37 degrees C and 20 degrees C ischemia. The properties of ST was similar to that of UW under conditions of 4 degrees C, although UW showed most excellent protective properties under conditions of 1 degrees C ischemia. These results suggested that, protective ability of preservation solution might be changed by the temperature during preservation period.