Prognostic value of combining cardiac myosin-binding protein C and N-terminal pro-B-type natriuretic peptide in patients without acute coronary syndrome treated at medical cardiac intensive care units

Abstract

We investigated the prognostic value of cardiac myosin-binding protein C (cMyC), a novel cardiospecific marker, both independently and in combination with N-terminal pro-B-type natriuretic peptide (NT-proBNP), for predicting 6-month all-cause mortality in patients without acute coronary syndrome (ACS) treated at medical (nonsurgical) cardiac intensive care units (CICUs). Admission levels of cMyC, high-sensitivity cardiac troponin T (hs-cTnT), and NT-proBNP were measured in 1032 consecutive patients (mean age; 70 years) without ACS hospitalized acutely in medical CICUs for the treatment of cardiovascular disease. Serum cMyC was closely correlated with hs-cTnT and moderately with NT-proBNP (r = 0.92 and r = 0.49, respectively, p < 0.0001). During the 6-month follow-up period after admission, there were 109 (10.6%) all-cause deaths, including 72 cardiovascular deaths. Both cMyC and NT-proBNP were independent predictors of 6-month all-cause mortality (all p < 0.05). Combining cMyC and NT-proBNP with a baseline model of established risk factors improved patient classification and discrimination beyond any single biomarker (all p < 0.05) or the baseline model alone (both p < 0.0001). Moreover, patients were divided into nine groups using cMyC and NT-proBNP tertiles, and the adjusted hazard ratio (95% confidence interval) for 6-month all-cause mortality in patients with both biomarkers in the highest vs. lowest tertile was 9.67 (2.65-35.2). When cMyC was replaced with hs-cTnT, similar results were observed for hs-cTnT. In addition, the C-indices for addition of cMyC or hs-cTnT to the baseline model were similar (0.798 vs. 0.800, p = 0.94). In conclusion, similar to hs-cTnT, cMyC at admission may be a potent, independent predictor of 6-month all-cause mortality in patients without ACS treated at medical CICUs, and their prognostic abilities may be comparable. Combining cMyC or hs-cTnT with NT-proBNP may substantially improve early risk stratification of this population.

Keywords: All-cause mortality; Cardiac myosin-binding protein C; High-sensitivity cardiac troponin T; Medical cardiac intensive care units; N-terminal pro-B-type natriuretic peptide; Non-acute coronary syndrome.