Beneficial effects of carvedilol on myocardial noª²reflow in miniª²swine models of acute myocardial infarction and reperfusion

    ZHAO Jingª²Lin, YANG Yueª²Jin, JING Zhiª²Cheng, WU Yongª²Jian, YOU Shiª²Jie, YANG Weiª²Xian, MENG Liang, TIAN Yi, CHEN Jiª²Lin, GAO Runª²Lin, CHEN Zaiª²Jia

    Department of Cardiovasology, Cardiovascular Institute, Fuwai Cardiovascular Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China

    ¡¾Abstract¡¿ AIM: To evaluate the effects of carvedilol (beta blocker) on myocardial noª²reflow in a miniª²swine model of acute myocardial infarction (AMI) and reperfusion. METHODS: Twentyª²four miniª²swine were randomized into 3 groups: control, carvedilolª²treatment [1 mg/(kg¡¤d)] and shamª²operation groups (n=8). Animals in the former 2 groups were subjected to 3 h of coronary occlusion followed by 60 min of reperfusion. Data on hemodynamics and coronary blood flow volume (CBV) were collected and the area of noª²reflow (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: ¢Ù In control group, left ventricular systolic pressure (LVSP), maximal rate of increase and decline in left ventricular pressure (¡Àdp/dtmax) and cardiac output(CO) significantly declined (P<0.05), while pulmonary capillary wedge pressure (PCWP) and left ventricular endª²diastolic pressure (LVEDP) significantly increased at the end of 3 h of left anterior descending (LAD) occlusion (P<0.01). Compared with those at the end of 3 h of occlusion, ¡Àdp/dtmax further significantly declined (P<0.05) at 60 min of reperfusion. In carvedilol group, the changes of LVSP, ¡Àdp/dtmax, CO and LVEDP were the same as those in the control group after 3 h of AMI. In contrast, LVSP, ¡Àdp/dtmax, CO, LVEDP and pulmonary capillary wedge (PCWP) recovered significantly at 60 min of reperfusion. ¢Ú In control group, the coronary ligation areas (LA) were similar (P>0.05) on both MCE in vivo and pathological evaluation and ANR was also both similar as high as 78.5% and 82.3% respectively, with final NA reaching 98.5% of LA. There was no significant difference in LA by both MCE and pathological evaluation between carvedilol and control groups, though ANR by both methods was significantly decreased to 24.9% and 25.8% respectively (both P<0.01), with final NA being also significantly decreased to 74.4% of LA in carvedilol group (P<0.05). ¢Û In control group, CBV was significantly declined to 45.8% and 50.6% of the baseline immediately after release of occlusion (3 h) and at 60 min of reperfusion (both P<0.01). In carvedilolª²treated group, CBV was also significantly declined immediately after release of occlusion (3 h) and at 60 min of reperfusion (both P<0.05), though significantly increased to 70.6% and 74.1% of the baseline, which were both significantly higher than those in control group (both P<0.01). CONCLUSION: Carvedilol is effective in preventing myocardial noª²reflow, improving left ventricular function and reducing infarct area during AMI and reperfusion in miniª²swines. ......