Effect of Preoperative Omitting Angiotensin？Converting Enzyme Inhibitor on Hemodynamics in Patients Undergoing Off Pump Coronary Artery Bypass Surgery

Background Angiotensin-converting enzyme inhibitors (ACE-I) have been widely used for cardiac patients. This study investigated the effect of omitting ACE-I medication on hemodynamics during induction of anaesthesia and operation in patients chronically treated with ACE-I undergoing off pump coronary artery bypass graft surgery (OPCAB). Methods Sixty patients scheduled for OPCAB were included in this study. Patients not treated with ACE-I were included in control group (Group 1, n = 20). And then, patients treated with ACE-I more than 4 weeks were randomly divided into two groups: continuing group including patients who continued ACE-I medication until the morning of surgery (Group 2, n = 20) and discontinuing group including patients who discontinued ACE-I one day before the surgery (Group 3, n = 20). Norepinephrine (8 µg/ml) was infused when systolic blood pressure decreased below 90 mmHg during induction and operation. Amount of norepinephrine infused and hemodynamic data were recorded. Results Significantly larger amount of norepinephrine was infused in Group 2 than in other two groups during obtuse marginal artery anastomosis. Total amount of norepinephrine infused during the all coronary anatsomosis was significantly larger in Group 2 than those values in other two groups. Conclusions Continuing ACE-I treatment until the morning of surgery significantly increased the use of norepinephrine during the anastomosis. In contrast, there was no significant difference in the use of norepinephrine between Group 1 and Group 3. Discontinuing ACE-I before the surgery may helpful to maintain hemodynamics stable during coronary anastomosis in OPCAB.ope