Randomized comparison of sevoflurane versus propofol to reduce perioperative myocardial ischemia in patients undergoing noncardiac surgery.

BACKGROUND: Volatile anesthetics provide myocardial preconditioning in coronary surgery patients. We hypothesized that sevoflurane compared with propofol reduces the incidence of myocardial ischemia in patients undergoing major noncardiac surgery. METHODS AND RESULTS: We enrolled 385 patients at cardiovascular risk in 3 centers. Patients were randomized to maintenance of anesthesia with sevoflurane or propofol. We recorded continuous ECG for 48 hours perioperatively, measured troponin T and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) on postoperative days 1 and 2, and evaluated postoperative delirium by the Confusion Assessment Method. At 6 and 12 months, we contacted patients by telephone to assess major adverse cardiac events. The primary end point was a composite of myocardial ischemia detected by continuous ECG and/or troponin elevation. Additional end points were postoperative NT-proBNP concentrations, major adverse cardiac events, and delirium. Patients and outcome assessors were blinded. We tested dichotomous end points by χ(2) test and NT-proBNP by Mann-Whitney test on an intention-to-treat basis. Myocardial ischemia occurred in 75 patients (40.8%) in the sevoflurane and 81 (40.3%) in the propofol group (relative risk, 1.01; 95% confidence interval, 0.78-1.30). NT-proBNP release did not differ across allocation on postoperative day 1 or 2. Within 12 months, 14 patients (7.6%) suffered a major adverse cardiac event after sevoflurane and 17 (8.5%) after propofol (relative risk, 0.90; 95% confidence interval, 0.44-1.83). The incidence of delirium did not differ (11.4% versus 14.4%; P=0.379). CONCLUSIONS: Compared with propofol, sevoflurane did not reduce the incidence of myocardial ischemia in high-risk patients undergoing major noncardiac surgery. The sevoflurane and propofol groups did not differ in postoperative NT-proBNP release, major adverse cardiac events at 1 year, or delirium.

Feasibility of measuring myocardial performance index of the right ventricle in anesthetized patients.

OBJECTIVE: Myocardial performance index, the sum of the 2 isovolumic times divided by the ejection time, contains information on global systolic and diastolic function. This study was performed to determine the feasibility of right ventricular myocardial performance index measurements if measured by transesophageal echocardiography in patients under general anesthesia and positive-pressure ventilation. DESIGN: A prospective cohort study. SETTING: A tertiary care university hospital. PARTICIPANTS: Twenty patients undergoing elective coronary artery bypass graft surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The feasibility of the right ventricular myocardial performance index measurements was assessed in awake patients by using transthoracic echocardiography and reassessed in the same patients under general anesthesia and positive-pressure ventilation using transesophageal echocardiography. The time from the cessation to the onset of 2 consecutive right ventricular inflows was measured as time A; the time from the onset to the cessation of right ventricular ejection was measured as time B. Myocardial performance index was calculated as follows: (time A-time B)/time B. A first reader independently measured all recordings twice to assess intrareader variability and a second reader once to assess interreader variability. Variability (%) was calculated as the mean absolute difference between 2 readings divided by their mean. The myocardial performance index could be measured for all patients. The point estimates of inter- and intraobserver variability of the right ventricular myocardial performance index measurements were 4.3% to 5% in awake patients and 17.8% to 19.6% in anesthetized patients. CONCLUSIONS: This finding questions the use of right ventricular myocardial performance index measurements in anesthetized patients under positive-pressure ventilation.