Association of pre-operative troponin levels with major adverse cardiac events and mortality after noncardiac surgery: A systematic review and meta-analysis

BACKGROUND: Circulating cardiac troponin levels are powerful predictors of prognosis in many clinical settings, but their association with outcomes after noncardiac surgery is unclear. OBJECTIVES: The aim of this systematic review was to summarise current evidence on the association of pre-operative troponin elevation with postoperative major adverse cardiac events (MACE) and mortality in patients undergoing noncardiac surgery. DESIGN: Systematic review of observational studies with meta-analysis. DATA SOURCES: PubMed, EMBASE and Science Citation Index Expanded (ISI Web of Science) from their inception to 1 October 2017. ELIGIBILITY CRITERIA: Observational studies reporting the associations between pre-operative troponin levels and MACE and all-cause mortality after noncardiac surgeries were included. RESULTS: Ten studies met the eligibility criteria. The entire body of evidence addressing the research question was based on a total of 10 371 patients: 4.7 to 68.3% (median 23.8%) of patients had elevated troponin levels before surgery. Elevated pre-operative troponin was significantly associated with short-term MACE (seven studies, 5180 patients: odds ratio (OR) 6.92, 95% confidence interval (CI) 3.85 to 12.42), short-term mortality (five studies, 6103 patients: OR 4.23, 95% CI 2.27 to 7.89) and long-term mortality (two studies, 760 patients: OR 2.51, 95% CI 1.47 to 4.29). The associations remained significant when only multivariate-adjusted results were analysed. Overall, the reviewers' certainty about the summary estimates of the associations was very low. CONCLUSION: Current evidence suggests that pre-operative high troponin levels are significantly associated with adverse cardiac events and mortality after noncardiac surgery. TRIAL REGISTRATION: This systematic review was registered in the International Prospective Register of Systematic Reviews (Centre for Reviews and Dissemination 42017077837).