Value of Early Cardiac Troponin I to Predict Long‐Term Adverse Events After Coronary Artery Bypass Graft Surgery in Patients Presenting with Acute Coronary Syndromes

BACKGROUND: High values of both preoperative and postoperative cardiac troponin I (cTnI) contribute to higher rates of short-term cardiac events following coronary artery bypass graft (CABG) surgery in patients with acute coronary syndrome (ACS). The prognostic value of very early cTnI in this context is unclear. HYPOTHESIS: Measurement of cTnI very early after admission to the emergency room can be used as a prognosticator for long-term outcomes after CABG. METHODS: We conducted a cohort study on 160 consecutive patients with ACS undergoing CABG at The John H. Stroger Jr. Hospital of Cook County (Chicago, IL) representing a total follow-up of 290.42 person-years. Adverse outcomes were defined as death or reinfarction. We used robust multivariate survival analyses to determine whether early cTnI measurement can independently predict the adverse outcomes in the study subjects. RESULTS: In univariate and stepwise multivariate Cox proportional hazards modeling we found that unit rise in early cTnI is associated with a 3% (95% confidence interval [CI]: 2%- 5%, p < 0.001) faster progression to long-term adverse events after CABG even after adjusting for the type of ACS. Prognostically, the most informative cut off value for cTnI was 5.6 ng/mL. Above this value, CABG patients progressed 2.58 times faster to adverse outcomes (95% CI: 1.05-6.36, p = 0.039). This effect remained after adjustment for other significant confounders namely, poor compliance to medications, female sex, Medicaid insurance, and electrocardiographic ischemia. CONCLUSION: Early cTnI measurement after admission can predict adverse outcomes after CABG. This association extends to long-term adverse events after CABG.