Systematic review and meta-analysis of postoperative troponin as a predictor of mortality and major adverse cardiac events after vascular surgery

Background: The prognostic value of asymptomatic perioperative troponin rise in vascular surgery is unclear. We conducted this systematic review and meta-analysis to determine the significance of clinical and subclinical troponin elevation after vascular surgery. Methods: We searched MEDLINE (Ovid), Embase (Ovid), and the Cochrane Library, without language restriction, from inception to May 2019 and included studies that reported associations between elevated postoperative troponin and short-term mortality, major adverse cardiac events (MACEs), or long-term mortality in a vascular surgery cohort. We synthesized study-level data on the maximally adjusted estimates using mixed effects modeling to generate summary odds ratios (ORs) for fixed-interval outcomes and summary hazard ratios for long-term mortality. Between-study heterogeneity was assessed with meta-regression. Methodologic quality and publication bias were formally assessed. Results: We included 24 studies involving 11,657 participants. Postoperative troponin was found to have a strong, positive association with short-term mortality (OR, 4.95; 95% confidence interval [CI], 2.87-8.52; 7 studies; 2661 people) and MACEs (OR, 5.33; 95% CI, 1.59-17.82; 12 studies; 5047 people) independent of meeting the criteria for myocardial infarction. Subclinical postoperative troponin elevation was further demonstrated to be associated with greater long-term mortality (hazard ratio, 1.94; 95% CI, 1.56-2.42; 13 studies; 7630 people; median follow-up, 24 months). Time to troponin sampling, hypertension, and type of surgery partially accounted for between-study heterogeneity. The methodologic quality of included studies was variable, and publication bias was not detected. Conclusions: Elevated postoperative troponin is strongly prognostic of worse survival and greater likelihood of MACEs after vascular surgery, regardless of whether symptoms of myocardial ischemia are present. These data support the benefit of postoperative troponin monitoring in identifying patients at increased risk of worse outcomes and who may be candidates for personalized preventive interventions.