Early dynamic risk stratification with baseline troponin levels and 90-minute ST-segment resolution to predict 30-day cardiovascular mortality in ST-segment elevation myocardial infarction: Analysis from CLopidogrel as Adjunctive ReperfusIon TherapY (CLARITY) - Thrombolysis in Myocardial Infarction (TIMI) 28

Abstract

Troponin is the preferred biomarker for risk stratification in non-ST elevation ACS. The incremental prognostic use of the initial magnitude of troponin elevation and its value in conjunction with ST-segment resolution (STRes) in ST elevation myocardial infarction (STEMI) is less well defined. Troponin T (TnT) was measured in 1,250 patients at presentation undergoing fibrinolysis for STEMI in CLARITY-TIMI 28. ST-segment resolution was measured at 90 minutes. Multivariable logistic regression was used to examine the independent association between TnT levels, STRes, and 30-day cardiovascular (CV) mortality. Patients were classified into undetectable TnT at baseline (n = 594), detectable but below the median of 0.12 ng/mL (n = 330), and above the median (n = 326). Rates of 30-day CV death were 1.5%, 4.5%, and 9.5%, respectively (P < .0001). Compared with those with undetectable levels and adjusting for baseline factors, the odds ratios for 30-day CV death were 4.56 (1.72-12.08, P = .002) and 5.81 (2.29-14.73, P = .0002) for those below and above the median, respectively. When combined with STRes, there was a significant gradient of risk, and in a multivariable model both baseline TnT (P = .004) and STRes (P = .003) were significant predictors of 30-day CV death. The addition of TnT and STRes to clinical risk factors significantly improved the C-statistic (from 0.86 to 0.90, P = .02) and the integrated discriminative improvement (7.1% increase) (P = .0009). Baseline TnT and 90-minute STRes are independent predictors of 30-day CV death in patients with STEMI. Use of these 2 simple, readily available tools can aid clinicians in early risk stratification.