Does cardiac troponin T, measured by a high-sensitive method, have a relationship to the survival of patients after myocardial infarction and with chronic heart failure?

Overview

Objective: The aim of this study was to determine whether elevated levels of high-sensitivity cardiac troponin T (hs-cTnT) in asymptomatic patients after myocardial infarction (MI) and in patients with signs of chronic heart failure (HF) are associated with their long-term survival. In patients with heart failure, in addition to hs-cTnT, the prognostic significance of B-type na triuretic peptide (BNP) and left ventricular ejection fraction (EF) was also evaluated. Design: Observational, retrospective. Setting: Institute of Clinical Biochemistry and Hematology, Faculty of Medicine in Plzeň, Charles University, and University Hospital in Plzeň. Material and methods: The study included 91 patients treated for myocardial infarction who were asymptomatic at the time of testing (MI group), and 38 patients treated for chronic heart failure who were followed in the cardiology outpatient clinics of the First and Second Departments of Internal Medicine, University Hospital in Plzeň. In all patients, hs-cTnT concentration was measured; in the HF group, BNP levels and left ventricular EF were additionally assessed. After 13–14 years, the effect of these parameters on survival was evaluated using Kaplan–Meier survival curves; in the HF group, the prognostic value of hs-cTnT, BNP, and EF was further analyzed using the Cox proportional hazards model. Results: Patients in the MI group were divided into quartiles according to hs-cTnT concentration. Patients in the 4th quartile (highest hs-cTnT levels) had a more than 2.5-fold higher risk of death compared with the combined 1st, 2nd, and 3rd quartiles (HR = 2.52; 95% CI: 1.132–5.601; p = 0.0236). HF patients were divided into tertiles according to hs-cTnT and BNP con centrations, and survival analysis was performed. No statistically significant differences in survival probability were observed among hs-cTnT tertiles. In contrast, BNP levels showed that survival of patients in the 3rd tertile (highest BNP) was signifi cantly worse compared with patients in the 1st and 2nd tertiles. The risk of death in the 3rd tertile was 3.3 times higher than in the 1st tertile (HR = 3.32; 95% CI: 1.273–8.679; p = 0.0434) and 1.5 times higher than in the 2nd tertile (HR = 1.52; 95% CI: 0.561–4.089), although this difference was not statistically significant. No significant difference in survival was observed between HF patients stratified by EF (≤ 25% vs. > 25%). In the Cox proportional hazards analysis of three predictors (BNP, hs-cTnT, and EF), only BNP emerged as an independent predictor of mortality (X² = 5.69; df = 1; p = 0.017). Conclusion: hs-cTnT is a suitable prognostic marker of survival in patients after myocardial infarction, but not in those with heart failure. The prognostic significance of BNP concentration for survival in HF patients was confirmed by two statistical methods.

Keywords:

myocardial infarction – heart failure – survival – cardiac troponin T – B type natriuretic peptide