AIM In order to identify the role of
renin angiotensin system (RAS) in
perioperative myocardial ischemia, we observed the
effect of captopril on heart during
perioperative period. METHODS Forty mongrel dogs were randomized for four groups (ten for each group):groupⅠ: control; groupⅡ: myocardial infarction(MI)model; groupⅢ: MI+partial gastrectomy; group Ⅳ: MI+captopril+partial gastrectomy. MI was produced except of the group Ⅰ. All animals were killed by overdose anesthetic and their cardiac samples of different part were taken for assaying of renin and angiotensin Ⅱ (AngⅡ). In the group Ⅲ and Ⅳ, the hemodynamic and biochemical values on baseline, pre and postoperation were examined. RESULTS In group Ⅲ, the partial gastrectomy decreased the maximal rate of left ventricular pressure rise (LV+d p /d t max ), cardiac index (CI), and increased left ventricular end diastolic pressure (LVEDP), time course of isovolumic pressure fall (T constant), total peripheral resistance (TPR), the levels of endothelin (ET), platelet α granule membrane glycoprotein (GMP 140), angiotensin Ⅱ (AngⅡ) and the plasma renin activity (PRA). In group Ⅳ, 40 minutes after administration of captopril, the TPR and plasma AngⅡ concentration were decreased, and the T constant and PRA were increased significantly, the partial gastrectomy attenuated the TPR and T constant, but did not affect other values. For the local RAS of heart, the levels of renin and AngⅡ in the risk and noninfarcted area were increased after myocardial infarction compared with the group Ⅰ . The partial gastrectomy induced further increases in the levels of AngⅡ in the risk and noninfarcted area. In group Ⅳ, there was no change in the level of renin and AngⅡ during perioperative period. CONCLUSIONS Partial gastrectomy performed after myocardial infarction may induce left ventricular systolic and diastolic dysfunction, systemic RAS reaction and local RAS reaction in the heart; captopril can improve left ventricular dysfunction and platelet dysfunction induced by abdominal operation.