Amrani M, Ledingham S, Jayakumar J, Allen N J, Rothery S, Severs N, Yacoub M
Department of Cardiothoracic Surgery, National Heart and Lung Institute, London, UK.
Circulation. 1992 Nov;86(5 Suppl):II280-8.
We have previously reported the superior protective properties of the University of Wisconsin (UW) solution compared with the St. Thomas solution (ST) in the rat heart subjected to the deep hypothermia (4 degrees C), thus demonstrating its possible use in cardiac transplantation. We thought it was important to evaluate the potential of the UW solution as a cardioplegic solution under the moderately hypothermic (20 degrees C) conditions of routine intraoperative myocardial protection.
Isolated rat hearts were subjected to 60 minutes of ischemia at 4 degrees C or 30 (or 60) minutes of ischemia at 20 degrees C with UW, ST, and ST plus 100 mM K (ST + 100) solutions. Coronary flow, mechanical function, endothelial function, and ultrastructure were observed. Mean time (seconds) to infuse 10 ml of cardioplegic solution under constant pressure, a measure of coronary vascular resistance at 4 degrees C and 20 degrees C, respectively, for each solution were ST, 69.2 +/- 6.9 and 64.7 +/- 3.8; UW, 142.2 +/- 8.8 and 187.2 +/- 10.0 (p < 0.01); and ST + 100, 78.2 +/- 8.0 and 176 +/- 8.1 (p < 0.001). Mean recovery values of cardiac output (expressed as percentage of its preischemic value) after 60 minutes of ischemia at 4 degrees C were ST, 95.5 +/- 2.1%; UW, 93.0 +/- 2.4%; and ST + 100, 96.5 +/- 1.5%. After 30 minutes of ischemia at 20 degrees C, values were ST, 88.0 +/- 1.3%; UW, 72.2 +/- 3.6% (p < 0.005 versus ST); and ST + 100, 53.3 +/- 1.8% (p < 0.001 versus ST).
The efficacies of UW and severely hyperkalemic cardioplegic solutions are affected by the degree of hypothermia under which they are used. Under moderate hypothermia (20 degrees C), severe hyperkalemia induces a marked increase in coronary vascular resistance that is associated with impaired myocardial protection. These studies discourage the use of UW for routine intraoperative cardioplegic arrest where the degree of hypothermia cannot be readily controlled. The ST solution does not share this constraint.
我们之前曾报道，在深低温（4℃）条件下，与圣托马斯溶液（ST）相比，威斯康星大学（UW）溶液对大鼠心脏具有更好的保护特性，从而证明其在心脏移植中的潜在用途。我们认为，在常规术中心肌保护的中度低温（20℃）条件下，评估UW溶液作为心脏停搏液的潜力很重要。
将离体大鼠心脏分别用UW溶液、ST溶液和ST加100 mM钾（ST + 100）溶液在4℃缺血60分钟或在20℃缺血30（或60）分钟。观察冠状动脉血流、机械功能、内皮功能和超微结构。在4℃和20℃下，分别测量每种溶液在恒压下输注10 ml心脏停搏液的平均时间（秒），以此作为冠状动脉血管阻力的指标，结果如下：ST溶液在4℃和20℃下分别为69.2±6.9和64.7±3.8；UW溶液在4℃和20℃下分别为142.2±8.8和187.2±10.0（p<0.01）；ST + 100溶液在4℃和20℃下分别为78.2±8.0和176±8.1（p<0.001）。在4℃缺血60分钟后，心输出量的平均恢复值（以缺血前值的百分比表示）分别为：ST溶液95.5±2.1%；UW溶液93.0±2.4%；ST + 100溶液96.5±1.5%。在20℃缺血30分钟后，心输出量的恢复值分别为：ST溶液88.0±1.3%；UW溶液72.2±3.6%（与ST溶液相比，p<0.005）；ST + 100溶液53.3±1.8%（与ST溶液相比，p<0.001）。
UW溶液和重度高钾心脏停搏液的疗效受使用时低温程度的影响。在中度低温（20℃）下，重度高钾血症会导致冠状动脉血管阻力显著增加，这与心肌保护受损有关。这些研究不主张在低温程度不易控制的常规术中心脏停搏时使用UW溶液。ST溶液不存在这一限制。
