Importance of high-sensitivity cardiac troponin T in the prediction of events in patients with acute coronary syndrome

Abstract

In acute myocardial infarction, the extent of myocardium compromise is closely related to prognosis. The early determination of infarct size is key to assess future risk. Objective: To evaluate cutoff points of myocardial damage markers and variables on admission in patients hospitalized for acute coronary syndrome and their relationship with events and ventricular remodeling. Materials and Methods: From January 1, to December 31, 2014, 92 patients with acute coronary syndrome were included. Hs-cTnT was measured on admission, as well as left ventricular ejection fraction (LVEF) by Doppler echocardiography, glycemia, white blood cells count and heart rate. The best cutoff point was selected for the ROC curve of hs-cTnT, LVEF, white blood cells count and heart rate. They were related to events. One-year follow-up and Doppler echocardiography were performed. Results: The average age of the population was 64.4 ± 15 years, 81% were male. The cutoff points, area under the curve, sensitivity and specificity and confidence interval for significant variables in univariate analysis were: hs-cTnT: ≥2,310 ng/L; area under the curve 0.87; sensitivity 84%; specificity 78%, P <0.001 (CI95% 0.78-0.94); white blood cells count: >11,910/mm3, area under the curve 0.70, sensitivity 64%, specificity 75%, P=0.003 (CI95% 0.57-0.82); LVEF <47%: area under the curve 0.76, sensitivity 68%, specificity 86%, P=0.001 (CI95% 0.64-0.88); heart rate: >85 beats per min, area under the curve 0.65, sensitivity 60%, specificity 76% and P=0.033 (CI95% 0.50-0.78). In the multivariate model, the predictors for composite events (death, reinfarction, heart failure, cardiogenic shock) were: hs-cTnT ≥2.310 ng/L, OR=17.22, P=<0.0001, (CI95% 3.5-83.31); NT-pro-BNP >900 pg/ml: OR=2.3, P=0.035 (CI95% 1.22-5.06); LVEF <47%: OR=1.9, P=0.028 (CI95% 1.02-3.52). Hs-cTnT ≥2.310 ng/L identified 58.3% of composite events compared to 7% in those with hs-cTnT lower than this value. When left ventricle remodeling was analyzed, in those with hs-cTnT ≥2.310 ng/L, a reduction in LVEF (52.4 to 49.2%, P=0.001) and an increase of end diastolic diameter (46.4 to 51.3 mm) were observed, (P=0.001). Two-year survival in those patients who had hs-cTnT ≥2.310ng/L on admission was 72% compared with 91.8% (p=0.01) of those with lower values of hs-cTnT. Conclusions: Hs-cTnT had the best cutoff point in the ROC curve; a cutoff point >2.310 ng/L identified events, and was an independent predictor together with LVEF, and NT-proBNP ≥900 pg/ml was associated with ventricular remodeling.