Purpose: To evaluate the prognostic ability of admission hs-cTnT in stratifying STEMI patients for risk of mortality.
Methods: Retrospective observational study including 3,113 consecutive STEMI patients undergoing PPCI between January 2010 and December 2014 at a single centre covering a population of 1.6 million in the north of England. Levels of hs-cTnT were determined at admission to the catheterisation laboratory. Clinical, procedural, and laboratory data were collected from the local service database. All-cause mortality data were retrieved from the UK national registry (June/2017). The clinical end-points were in-hospital and overall mortality. Core clinical models for in-hospital and overall mortality prediction were determined by multivariate Cox-regression analyses. Kaplan-Meier survival and multivariate Cox-regression analyses were employed to evaluate the association between hs-cTnT and mortality. Net reclassification index (NRI) analysis was used to determine the power of hs-cTnT to reclassify patients into correct GRACE score categories for risk of in-hospital and overall mortality over the core predictive models. Data are presented as mean and standard deviation (±SD) or median and interquartile range, as appropriate. A p value < 0.05 was considered statistically significant.
Results: Mean age was 62.9 (±12.7) years. In-hospital mortality rate was 3% (n = 94) whereas overall mortality was 16.4% (n = 509) at a mean follow-up period of 51 (±21) months. Ascending quartiles of hs-cTnT were associated with increasing in-hospital and overall mortality (log rank < 0.001). Hs-cTnT values > 515ng/L (4th quartile) were independently associated with higher risk of in-hospital mortality [hazard ration (HR) per highest to lower quartiles = 2.39, p = 0.001] after adjusting for the core in-hospital mortality prediction model. Similarly, hs-cTnT levels > 515ng/L independently predicted overall mortality (HR per highest to lower quartiles = 1.25, p = 0.044) when adjusted for the core clinical model of overall mortality prediction. In addition, ascending quartiles of hs-cTnT correctly reclassified 43.9% (p < 0.001) and 48.4% (p < 0.001) of patients into risk categories for in-hospital and overall mortality, respectively.
Conclusion: Admission hs-cTnT is an independent predictor of mortality and improves risk stratification of STEMI patients post-PPCI. Future studies should assess its usefulness as a tool to guide secondary prevention in this population.