Experimental Research Of No-reflow After Acute Myocardial Infarction And Reperfusion And Its Intervention With Medications

Objective To evaluate the effects of tong xin-luo, adenosine, diltiazem and nicorandil on myocardial no-reflow in a mini-swine model of acute myocardial infarction (AMI) and reperfusion.Methods Sixty-four mini-swines were randomized into 8 study groups: 8 in control, 24 in low (0.05g · kg^-1 · d^-1 for 3 days), medium (0.2g · kg^-1 · d^-1 for 3 days) and high dose (0.5g · kg^-1 · d^-1 for 3 days) of tong-xin-luo-pretreated, 8 in adenosine-treated(100ug/kg/min infusion), 8 in diltiazem-treated(2mg/min intracoronary), 8 in nicorandil-treated (a bolus of 150ug/kg followed by 3ug/kg/min infusion) and 8 in sham-operated. Animals in the former seven groups were subjected to 3 hours of left anterior descending (LAD) coronary occlusion followed by 60 minutes 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 (1) In control group, systolic and diastolic blood pressure(SBP and DBP), left ventricular systolic pressure(LVSP), the maximum change rate of left ventricular pressure rise and fall (±dp/dt_max ) and cardiac output(CO) significantly declined ( P<0.05-0.01), while left ventricular end-diastolic pressure(LVEDP) significantly increased at the end of 3 hours of LAD occlusion (both P<0.01). Compared with those at the end of 3 hours of occlusion, ±dp/dt_max further significantly declined (both P<0.05) at 60 minutes of reperfusion. In the six treated groups, the changes of LVSP, ±dp/dt_max,CO and LVEDP were the same as those in the control group after 3 hours of AMI, in contrast, ±dp/d_tmax ,CO and LVEDP recovered significantly at 60 minutes of reperfusion in adenosine, nicorandil and high-dose tong-xin-luo groups (all P<0.05).