Identifying biomarkers and establishing their threshold values concordantly with LV remodeling for predicting long-term MACE following STEMI

Following STEMI, diastolic function is altered by myocardial necrosis and microvascular disfunction. Consistent with these changes, the cardiac troponins are degraded and the release of cardiac natriuretic hormones inhibit the pathophysiological mechanisms responsible for ventricular remodeling (adverse diastolic remodeling, worsening of diastolic function ≥ 1 grade or persisting of restrictive pattern), thus NT-proBNP in non-acute phase of STEMI (early phase of ventricular remodeling) is a strong predictor of heart failure and mortality.

Prospective study population consisted of 96 consecutive patients with STEMI of onset <12h who underwent primary percutaneous coronary intervention (pPCI). The levels of creatine kinase (CK), the MB fraction of creatine kinase (CK-MB), troponin I, NT-proBNP, CRP, and other routine laboratory parameters were measured. In particular, we evaluated the levels troponin I on the first and seventh days (enzyme-linked immunosorbent assay (ELISA) ) and NT-proBNP in seventh day ( electro-chemiluminiscence method) after reperfusion therapy in all patients.

The follow-up period was 12 months. Baseline clinical characteristics of patients are presented in table 1. A receiver operating characteristics (ROC) curve plots the true positive rate against the false positive rate at different cut-off points for NT-proBNP AUC=0.69 (95% CI, 0.53-0.85), p=0.012 and other biomarkers (Figure 1 and Table 2). Kaplan-Meier curves were used to show the number of MACE and the proportion of patients that survived at each even time point based on the cut-off value of NT-proBNP on the seventh day (1131pg/mL). The log-rank test for the difference in survival resulted in a p value of 0.007 (Figure 2.) In total 17 (17.7%) patients suffered from heart failure, 5 (5.2%) among patients with NT-proBNP value ≤ 1131pg/mL and 12 (12.49%) with value > 1131pg/mL (p < 0.001).

Adverse diastolic remodeling in the non-acute phase of STEMI (early phase of ventricular remodeling) were associated with high rates of MACE after STEMI, with significant variability in the NT-proBNP values.