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目的 探讨心肌顿抑时心肌微血管功能改变以及静脉心肌声学造影方法的价值。方法 制备左前降支冠脉 (LAD)不同阻断时间 ( 15min和 60min)后再灌注犬心肌顿抑模型 ,在不同观察时间点静脉注射含全氟丙烷声振白蛋白微泡造影剂 ,采用二次谐波成像和间歇发射技术行心肌声学造影 (MCE)。由主动脉根部分别注射乙酰胆碱 (ACH)和硝酸甘油 (NG)后重复MCE并计算用药后、前二维超声上所示心肌灰阶峰值 (PVI)和峰值比值 (PVIR)。结果 ①心肌顿抑早期心肌PVI显著增高 ,60min后恢复至结扎前水平 ;② 15minLAD阻断组再灌注早期NG PVIR和ACH PVIR明显减低 ,但分别在再灌注 60min和 12 0min时恢复至结扎前水平 ;③60minLAD阻断组再灌注早期NG PVIR减低 ,至再灌注 12 0min时才恢复到结扎前水平 ,而再灌注期ACH PVIR明显减低 ,随着再灌注时间的延长虽有逐渐回升趋势 ,但至再灌注 12 0min仍未恢复至结扎前水平。结论 ①心肌顿抑早期微血管扩张 ,血液灌注增加 ,此后较快恢复正常 ;②顿抑心肌微血管内皮受损 ,血管内皮依赖性舒张功能减弱 ,其恢复速度与原缺血时间长短有关。
Objective To investigate the changes of myocardial microvascular function during myocardial stunning and the value of intravenous myocardial contrast echocardiography. Methods Myocardial stunned canine model was established after different occlusion time (15min and 60min) of left anterior descending coronary artery (LAD). Perforated propofol microbubbles were perfused intravenously at different time points. Sub-harmonic imaging and intermittent emission technique underwent myocardial contrast echocardiography (MCE). MCE was repeated after ACH and NG were injected into the aortic root, and PVI and PVIR were calculated as shown on the first two-dimensional ultrasound. Results ① Myocardial stunned myocardium early PVI increased significantly and returned to pre-ligation level after 60min; ② NG PVIR and ACH PVIR significantly decreased in the early reperfusion period after 15minLAD blockade, but returned to pre-ligation level at 60min and 120min after reperfusion, respectively ; ③The level of NG PVIR in the 60minLAD block group was reduced at the early reperfusion stage and returned to pre-ligation level at 120min after reperfusion, while the ACIR PVIR decreased significantly at reperfusion stage and gradually increased with the reperfusion time, Perfusion 12 0min has not yet returned to pre-ligation levels. Conclusions ① Myocardial stunned early microvascular dilatation, increased blood perfusion, then returned to normal soon after; ② stunned myocardial microvascular endothelial damage, endothelium-dependent vasodilatation decreased, the recovery rate and the length of the original ischemia related.