Value of Serial Troponin T Measures for Early and Late Risk Stratification in Patients With Acute Coronary Syndromes

Abstract

Background —The baseline cardiac troponin T (cTnT) level strongly predicts short-term mortality in acute coronary syndromes, but the added value of later measures to predict short- and long-term outcome and in the context of baseline clinical characteristics is unclear. Methods and Results —Relations between baseline, peak, and 8- and 16-hour (late) cTnT results and outcomes were assessed in 734 patients in a GUSTO-IIa substudy. Proportional-hazards models assessed the prognostic information gained from late cTnT when added to a mortality model containing the baseline cTnT result and clinical factors. At baseline, 260 patients were cTnT-positive (>0.1 ng/mL), 323 became positive later, and 151 remained negative (≤0.1 ng/mL). Mortality at 30 days was 10% in the baseline-positive group, 5% in late-positive patients, and 0% in negative patients. After adjustment for baseline characteristics, any positive cTnT result predicted 30-day mortality (baseline, χ 2 =8.96, P =0.0113; 8-hour, χ 2 =6.51, P =0.0107; 16-hour, χ 2 =8.40, P =0.0038). Both the 8- and the 16-hour results added to the strength of the baseline result (baseline+8-hour, χ 2 =12.04, P =0.0072; baseline+16-hour, χ 2 =13.52, P =0.0036). Only age and ST-segment elevation were stronger predictors of 30-day mortality than baseline cTnT; results were similar for prediction of 1-year mortality. Most of the mortality difference between cTnT-positive and -negative patients occurred within the first 30 days. Conclusions —The cTnT level is a strong, independent predictor of short-term outcome in acute coronary syndromes. The addition of later samples to a baseline level is useful to evaluate the risk of serious cardiac events.