Favorable remodeling enhances recovery of regional myocardial function in the weeks after infarction in ischemically preconditioned hearts.
Favorable remodeling enhances recovery of regional myocardial function in the weeks after infarction in ischemically preconditioned hearts.
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DOI：
10.1161/01.cir.102.5.579
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发表时间：
2000-08
期刊：
影响因子：
37.8
通讯作者：
M. Cohen;Xi-ming Yang;T. Neumann;G. Heusch;J. Downey
中科院分区：
文献类型：
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作者：
M. Cohen;Xi-ming Yang;T. Neumann;G. Heusch;J. Downey
背景 在之前的一项研究中，我们发现，在再灌注 72 小时后，经过缺血预处理的有意识、长期使用仪器的兔子的缺血区节段缩短的恢复明显好于对照动物。然而，尽管这一再灌注期被认为足以使患者从击晕中恢复，但区域功能相对于梗塞面积而言却过低。方法和结果 为了进一步表征左心室区域功能的恢复情况，在兔子的左冠状动脉分支周围长期安装球囊封堵器和一对超声波晶体以监测缺血区的节段缩短。预处理组在30分钟闭塞之前进行1个5分钟闭塞/10分钟再灌注周期，而对照兔子仅经历30分钟闭塞。在 30 分钟的闭塞期间，所有监测的节段要么是运动障碍，要么是无运动。再灌注24小时之前，两组之间的功能没有差异。 72 小时时，对照心脏的收缩期缩短平均仅为缺血前值的 5%，而预处理心脏的收缩期缩短为基线的 29%。到第 21 天，对照心脏的收缩期缩短平均为 26%，预处理心脏的收缩期缩短为 65%（P<0.02），并且似乎已达到平台期。对照心脏和预处理心脏的梗塞面积分别为 31.4+/-2.8% 和 15.5+/-2.1%。此外，在缺血预处理的心脏中，对于晶体间心肌段中任何给定数量的微梗塞，区域功能的恢复均优于对照组（P=0.02）。结论 预处理心脏的逐步改善与缺血区的有利重塑最为一致，而预处理过程似乎加剧了缺血区的重塑。
BACKGROUND In a previous study, we found that recovery of segment shortening in the ischemic zone of conscious, chronically instrumented rabbits was significantly better in ischemically preconditioned than control animals after 72 hours of reperfusion. However, although this period of reperfusion was felt to be sufficient to allow recovery from stunning, regional function was disproportionately low for the size of the infarcts. METHODS AND RESULTS To further characterize the recovery of left ventricular regional function, rabbits were chronically instrumented with a balloon occluder around a branch of the left coronary artery and a pair of ultrasonic crystals to monitor segment shortening in the ischemic zone. The preconditioned group had 1 cycle of 5-minute occlusion/10-minute reperfusion before a 30-minute occlusion, whereas control rabbits experienced only the 30-minute occlusion. All monitored segments were either dyskinetic or akinetic during the 30-minute occlusion. There was no difference in function between the 2 groups until 24 hours of reperfusion. At 72 hours, systolic shortening in control hearts averaged only 5% of the preischemic value, whereas shortening was 29% of baseline in preconditioned hearts. By day 21, systolic shortening averaged 26% in control hearts and 65% in preconditioned hearts (P<0.02) and appeared to have reached a plateau. Infarct size was 31.4+/-2.8% and 15.5+/-2.1% in control and preconditioned hearts, respectively. Moreover, in ischemically preconditioned hearts, the recovery of regional function was better than in controls for any given amount of microinfarction in the myocardial segment between crystals (P=0.02). CONCLUSIONS The progressive improvement in preconditioned hearts is most consistent with favorable remodeling in the ischemic zone, which the preconditioning process seems to accentuate.