Melendez F J, Gharagozloo F, Sun S C, Benfell K, Austin R E, Shemin R J, Cohn L H
Department of Surgery, Harvard Medical School, Boston, Mass.
J Thorac Cardiovasc Surg. 1988 Apr;95(4):613-7.
We investigated the effects of diltiazem cardioplegia on myocardial function and infarct size in the region of the left anterior descending artery after acute occlusion and reperfusion during cardiopulmonary bypass. Sheep (30 kg) were subjected to 1 hour of regional myocardial ischemia by occlusion of the left anterior descending artery and assigned to a control (n = 8) or experimental group (n = 5). Control animals were placed on cardiopulmonary bypass and the heart arrested with potassium cardioplegia. The left anterior descending artery was released and two additional doses of 100 ml of cardioplegic solution were infused during the total cross-clamp time of 30 minutes. The animals were then weaned from bypass after 1 hour and beating, working reperfusion maintained for an additional 4 hours. The experimental group followed the same protocol except that the cardioplegic solution contained diltiazem (1.4 mg/L). Segmental myocardial function was determined by pairs of ultrasonic crystals in the area at risk, control segment, and minor axis. Global contractility was determined from maximum derivative of left ventricular pressure and cardiac output. The area at risk was determined by injecting monastral blue dye into the left atrium with the left anterior descending artery briefly reoccluded, and the area of necrosis was determined by measuring with a planimeter non-triphenyltetrazolium chloride stained areas in the sectioned left ventricle. After 5 hours of reperfusion, not only did the diltiazem group demonstrate better global contractility as defined by the derivative of left ventricular pressure (1853 +/- 292 versus 979 +/- 191, p = 0.05) but, in addition, the systolic shortening in the ischemic area improved significantly when compared with the control group (9.4 +/- 4 versus 2.13 +/- 0.77, p = 0.05). The group receiving diltiazem cardioplegia had an area of necrosis to area at risk ratio of 31.4% +/- 3%, which was significantly better than this ratio in the control group of 60.75% +/- 7% (p = 0.01). Diltiazem cardioplegia results in improved global and segmental contractility and limits the infarct size after occlusion of the left anterior descending artery and surgical reperfusion.
我们研究了地尔硫䓬心脏停搏液对体外循环期间急性闭塞和再灌注后左前降支区域心肌功能和梗死面积的影响。选用体重30kg的绵羊，通过闭塞左前降支使其经历1小时的局部心肌缺血，然后将其分为对照组（n = 8）和实验组（n = 5）。对照组动物进行体外循环，并用钾心脏停搏液使心脏停搏。松开左前降支，在30分钟的总阻断时间内再注入两剂100ml心脏停搏液。然后在1小时后停止体外循环，使心脏恢复跳动并继续工作再灌注4小时。实验组遵循相同方案，只是心脏停搏液中含有地尔硫䓬（1.4mg/L）。通过位于危险区域、对照节段和短轴处的成对超声晶体测定节段性心肌功能。通过左心室压力的最大变化率和心输出量测定整体收缩性。通过在左前降支短暂重新闭塞时向左心房注射亚甲蓝染料来确定危险区域，通过用面积计测量切片左心室中未用氯化三苯基四氮唑染色的区域来确定坏死面积。再灌注5小时后，地尔硫䓬组不仅在左心室压力变化率方面表现出更好的整体收缩性（1853±292对979±191，p = 0.05），而且与对照组相比，缺血区域的收缩期缩短也显著改善（9.4±4对2.13±0.77，p = 0.05）。接受地尔硫䓬心脏停搏液的组坏死面积与危险区域面积之比为31.4%±3%，明显优于对照组的60.75%±7%（p = 0.01）。地尔硫䓬心脏停搏液可改善整体和节段性收缩性，并限制左前降支闭塞和手术再灌注后的梗死面积。
