ISOFLURANE ANESTHESIA AND MYOCARDIAL-ISCHEMIA - COMPARATIVE RISK VERSUS SUFENTANIL ANESTHESIA IN PATIENTS UNDERGOING CORONARY-ARTERY BYPASS GRAFT-SURGERY

Whether isoflurane has the potential to produce coronary artery steal and associated myocardial ischemia is still controversial. Previous studies addressing this issue in humans did not purposefully control hemodynamics or use continuous measures of myocardial ischemia. The authors used transesophageal echocardiography (TEE) and continuous Holter electrocardiography (ECG) to study the relative risk of myocardial ischemia during isoflurane or sufentanil anesthesia under strict control of hemodynamics in 186 high-risk patients undergoing elective coronary artery bypass graft (CABG) surgery. Overall, hemodynamics were well controlled (increased heart rate = 9.8%; increased systolic blood pressure = 7.1%; decreased systolic blood pressure = 10.8% of total prebypass time compared with preoperative baseline values), with no difference between the two anesthetics. In the 162 patients with interpretable TEE recordings, moderate to severe TEE ischemic episodes (grade change greater-than-or-equal-to 2) developed in 33 (21%) during the prebypass period, with no difference between isoflurane (12 of 56 = 21%) and sufentanil (21 of 106 = 20%) (P = 0.97). The duration and severity of TEE episodes were not significantly different between the two groups. No correlation was observed between TEE ischemic episodes and isoflurane concentrations (range, 0.47-1.75%). In the 181 patients with interpretable ECG recordings, ECG evidence of ischemia developed in 34 (19%) during the prebypass period, with no difference between isoflurane (12 of 59 = 20%) and sufentanil (22 of 122 = 18%) (P = 0.87). The duration and severity of electrocardiographic ischemic episodes were also similar in patients receiving either isoflurane or sufentanil. Four of the 62 patients (6%) who received isoflurane had an adverse cardiac outcome versus 15 of 124 patients (12%) who received sufentanil (P = 0.34). The authors' findings demonstrate that, when hemodynamics are controlled, the incidence of myocardial ischemia (TEE or ECG) during isoflurane and sufentanil anesthesia is similar.