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).