The effects of volatile anesthetics on cardiac ischemic complications and mortality in CABG: a meta-analysis

Purpose: Coronary artery bypass graft surgery (CABG) is associated with cardiac complications, including ischemia, acute myocardial infarction (AMI), and death. Volatile anesthetics have been shown to have a preconditioning-like effect. This systematic review assesses the effects of volatile anesthetics on cardiac ischemic complications and morbidity after CABG. Methods: Data were obtained, without language restriction, from searches of MEDLINE, Science Citation Index, PubMed, and reference lists. We included only prospective randomized controlled trials evaluating volatile anesthetics during CABG. Two reviewers independently abstracted data on myocardial ischemia, acute myocardial infarction (AMI), and death. Treatment effects were calculated as odds ratio (OR) with 95% confidence intervals (CI) for binary data, and weighted mean difference (WMD) with 95% Cl for continuous data. Principal findings: Thirty-two studies (2,841 patients) were included. In comparison with iv anesthesia, volatile anesthetics were associated with reduced all-cause mortality (OR, 0.65; 95% Cl, 0.36-1.18; P = 0.16). Enflurane was associated with increased AMI (OR, 1.34; 95% CI, 0.68-2.64; P = 0.40) whereas sevoflurane and desflurane reduced cardiac troponin (cTnI) at six hours, 12 hr, 24 hr [WMD, -1.45; 95% CI (-1.73, -1.16); P < 0.00001], and 48 hr after operation. Conclusion: This meta-analysis demonstrates sevoflurane and desflurane reduce the postoperative rise in cTnI. Sevoflurane-mediated reduction in cardiac troponin was associated with improved long-term outcomes in one study. This meta-analysis was not able to show that these positive effects on troponin were translated into improved clinical outcomes. Well-designed large randomized control trials are needed to further elucidate the differential cardio-protective effects of volatile anesthetics.