Brown W M, Jay J L, Gott J P, Huang A H, Horsley W S, Dorsey L M, Katzmark S, Siegel R J, Guyton R A
Carlyle Fraser Heart Center, Crawford Long Hospital, Emory University, Atlanta, Georgia.
Ann Thorac Surg. 1993 Jan;55(1):32-41; discussion 41-2. doi: 10.1016/0003-4975(93)90470-3.
Three myocardial protection techniques were studied in a canine model of acute myocardial ischemia with subsequent revascularization. Eighteen animals were randomly assigned to one of three treatment regimens: cold oxygenated crystalloid cardioplegia (CC), cold blood cardioplegia with modified reperfusate (CB), and continuous aerobic warm blood cardioplegia (WB) (n = 6 per group). Systemic hypothermic cardiopulmonary bypass (28 degrees C), antegrade arrest, and intermittent retrograde and antegrade delivery were used for the CC and CB groups. Systemic normothermic cardiopulmonary bypass, antegrade arrest, and continuous retrograde delivery were used for the WB group. Fifteen minutes of warm global ischemia was followed by occlusion of the left anterior descending coronary artery (15-minute duration) and simultaneous initiation of cardioplegic arrest (60-minute duration) to simulate clinical revascularization. After reperfusion, the animals were separated from cardiopulmonary bypass. Myocardial function, electrocardiogram, myocardial energetics, water content, histopathology, and defibrillation requirements were compared between groups. There was no significant difference in maximum elastance, myocardial oxygen consumption, myocardial edema, or histopathologic evidence of injury between groups. However, overall ventricular function, assessed by the slope of the preload recruitable stroke work relationship, was significantly better for the WB group (p = 0.04) (WB, 73 +/- 9; CB, 56 +/- 7; CC, 47 +/- 5). Diastolic function as assessed by the slope of the stress-strain relationship was significantly worse overall for the cold groups (p = 0.001) (WB, 20 +/- 2.2; CB, 39 +/- 1.3; CC, 37 +/- 3.1). Myocardial injury as assessed by ST segment elevation (millimeters) was less for the WB group (p = 0.03) (WB, 0.4 +/- 0.3; CB, 1.7 +/- 0.2; CC, 1.6 +/- 0.7). Countershocks necessary to restore sinus rhythm after cross-clamp removal were fewer in the WB group (p = 0.03) (WB, 0.8 +/- 0.3; CB, 4.0 +/- 1.2; CC, 5.5 +/- 1.5). In this model of acute global myocardial ischemia, continuous aerobic warm blood cardioplegia has important advantages over two widely used clinical hypothermic protection techniques.
在急性心肌缺血并随后进行血运重建的犬类模型中研究了三种心肌保护技术。18只动物被随机分配到三种治疗方案之一：冷氧合晶体停搏液（CC）、含改良再灌注液的冷血停搏液（CB）和持续有氧温血停搏液（WB）（每组n = 6）。CC组和CB组采用全身低温心肺转流（28℃）、顺行灌注停搏、间歇性逆行和顺行给药。WB组采用全身常温心肺转流、顺行灌注停搏和持续逆行给药。15分钟的温暖全心缺血后，闭塞左前降支冠状动脉（持续15分钟）并同时开始停搏液灌注停搏（持续60分钟）以模拟临床血运重建。再灌注后，动物脱离心肺转流。比较了各组之间的心肌功能、心电图、心肌能量代谢、含水量、组织病理学和除颤需求。各组之间在最大弹性、心肌氧消耗、心肌水肿或损伤的组织病理学证据方面无显著差异。然而，通过前负荷可募集搏功关系斜率评估的整体心室功能，WB组明显更好（p = 0.04）（WB，73±9；CB，56±7；CC，47±5）。通过应力-应变关系斜率评估的舒张功能，冷灌注组总体上明显更差（p = 0.001）（WB，20±2.2；CB，39±1.3；CC，37±3.1）。通过ST段抬高（毫米）评估的心肌损伤，WB组较轻（p = 0.03）（WB，0.4±0.3；CB，1.7±0.2；CC，1.6±0.7）。在松开交叉钳夹后恢复窦性心律所需的反搏次数，WB组较少（p = 0.03）（WB，0.8±0.3；CB，4.0±1.2；CC，5.5±1.5）。在这个急性全心心肌缺血模型中，持续有氧温血停搏液相对于两种广泛应用的临床低温保护技术具有重要优势。
