The prognostic value of postoperative cardiac troponin I and T for major adverse cardiac events after coronary artery bypass grafting: a systematic review

Background: This systematic review describes the prognostic value of postoperative cardiac high-sensitive troponin I and T as risk markers for major adverse cardiac events (MACE) after coronary artery bypass graft (CABG) surgery and their predictive performance. Methods: PubMed and Embase were searched up to 14 October 2024. Studies were included if they reported either the association between cardiac troponin I and T and MACE (using risk-, hazard-, or odds ratios) or the accuracy of troponin I and T based prediction models for MACE (using c-statistics and calibration) within 72 h after CABG. MACE was defined as the composite of myocardial infarction, coronary artery revascularisation, cardiac death, non-fatal cardiac arrest, and heart failure. Risk of bias was assessed using the Quality in Prognostic Studies tool. Results: Out of 2273 studies, 10 studies were included. Five studies reported on troponin I (1956 patients) and five on troponin T (5615 patients). MACE composites were heterogenous, with only two studies using an identical composite. Increased postoperative troponin I and T concentrations were associated with higher risk of MACE, with a hazard ratio range of 1.6–11.1 for troponin I (n=2) and an odds ratio range of 0.9–67.9 for troponin T (n=5). Discriminative performance was moderate to good for troponin I (n=3, c-statistics range 0.60–0.81) and moderate for troponin T (n=3, c-statistics range 0.72–0.77). No studies reported calibration for troponin I. For troponin T (n=1) calibration was good for in-hospital MACE (Hosmer–Lemeshow P=0.20). Risk of bias was moderate to high across domains. Conclusions: Postoperative cardiac troponin I and T biomarkers are associated with postoperative MACE after CABG. The current evidence on the predictive value for postoperative MACE is insufficient to use troponin I and T for risk stratification.