缺血预适应对猪急性心肌梗死再灌注后无再流的影响

目的评价缺血预适应(IPC)防治猪急性心肌梗死(AMI)再灌注后无再流的作用.方法中华小型猪24只随机分成对照组、IPC组和假手术组,每组8只.冠状动脉结扎3 h,松解1 h制备AMI再灌注模型.AMI前、AMI后3 h和再灌注1 h后均行血流动力学测定,包括左室收缩压(LVSP)、左室舒张末压(LVEDP)、心排量(CO)和左心室内压最大收缩和舒张变化速率(±dp/dtmax).各组使用电磁流量计于AMI前5 min,对照组和IPC组于再灌注后即刻和1 h时记录冠脉血流量,应用心肌声学造影(MCE)检查及病理学分析测定无再流范围(ANR).结果与AMI前相比,对照和IPC两组AMI后3 h和再灌注后1 h LVSP、CO和±dp/dtmax均显著下降(P＜0.05,P＜0.01),LVEDP显著升高(P＜0.01);对照组再灌注后1 h仅LVSP比AMI后3 h显著恢复(P＜0.05),±dp/dtmax继续显著下降(P＜0.05);IPC组再灌注后1 h LVSP、LVEDP、±dp/dtmax和CO均比AMI 3 h显著恢复(P＜0.05,P＜0.01).IPC组MCE和病理染色所测的冠脉结扎区心肌范围高度一致(P＞0.05),再灌注后ANR分别为(16.4±2.24)%和(17.5±2.87)%,心肌坏死范围(NA)占LA的(78.4±3.62)%;IPC组结扎区心肌范围与对照组相比,差异无显著性(均P＞0.05),但两方法所测ANR和NA均显著小于对照组(P＜0.05,P＜0.01).对照和IPC两组再灌注即刻和再灌注后1 h冠脉血流量明显低于AMI前(均P＜0.01),IPC组再灌注即刻和再灌注后1 h冠脉血流量均比对照组显著增加(P＜0.05).结论IPC能有效防治心肌梗死再灌注后无再流,改善心功能,缩小梗死面积.

Beneficial effects of ischemic preconditioning on myocardial no-reflow in a mini-swine model of acute myocardial infarction and reperfusion

OBJECTIVE: To evaluate the effects of ischemic preconditioning (IPC) on myocardial no-reflow in a mini-swine model of acute myocardial infarction (AMI) and reperfusion. METHODS: Twenty-four mini-swines were randomized into 3 study groups: 8 in control, 8 in IPC and 8 in sham-operated. Animals in the former two groups were subjected to 3 hours of coronary occlusion followed by 1 hour of reperfusion. Data on hemodynamics and coronary blood flow volume (CBV) were collected, and the area of no-reflow (ANR) was evaluated with both myocardial contrast echocardiography (MCE) in vivo and pathological means. Necrosis area (NA) was measured with triphenyltetrazolium chloride (TTC) staining. RESULTS: In control group, left ventricular systolic pressure (LVSP), the maximum change rate of left ventricular pressure rise and fall (+/-dp/dtmax) and cardiac output (CO) significantly declined (P < 0.05, P < 0.01), while left ventricular end-diastolic pressure (LVEDP) significantly increased at the end of 3 hours of left anterior descending coronary artery occlusion (both P < 0.01), with +/-dp/dtmax further significantly declined (both P <0.05) at 1 hour of reperfusion. In IPC group, LVSP, +/-dp/dtmax, CO and LVEDP significantly recovered at 1 hour of reperfusion, compared with those in control group. In IPC group, the coronary ligation area was similar on both MCE in vivo and pathological evaluation (P > 0.05), and ANR was both also similarly as high as (16.4 +/- 2.24) % and (17.5 +/- 2.87) %, respectively, with final necrosis area (NA) reaching (78.4 +/- 3.62) %. In IPC group, ANR and final NA were significantly lower than those in control group (P < 0.05, P < 0.01). In the control group, coronary blood flow volumn immediately after release of 3 hours occlusion and at 1 hour of reperfusion were significantly lower than the baseline (both P < 0.01). In IPC group, coronary blood flow volumn were significantly higher than those in the control group (both P < 0.01). CONCLUSION: IPC is effective to prevent myocardial no-reflow, improve left ventricular function and decrease infarct area.