A prospective study of patients with refractory angina: outcomes and the role of high-sensitivity troponin T.

BACKGROUND: The predictors of cardiovascular events in patients with chronic refractory angina are limited. High-sensitivity cardiac troponin T (hs-cTnT) assays are biomarkers that may be used to determine the prognosis of patients with stable coronary artery disease.

HYPOTHESIS: Hs-cTnT is a predictor of death and nonfatal myocardial infarction (MI) in patients with refractory angina.

METHODS: We prospectively enrolled 117 consecutive patients in this study. A heart team ruled out myocardial revascularization feasibility after assessing recent coronary angiograms; evidence of myocardial ischemia served as an inclusion criterion. Optimal medical therapy was encouraged via outpatient visits every 6 months; plasma hs-cTnT levels were determined at baseline. The primary endpoint was the composite incidence of death and nonfatal MI.

RESULTS: During a median follow-up period of 28.0 months (interquartile range, 18.0-47.5 months), an estimated 28.0-month cumulative event rate of 13.4% was determined via the Kaplan-Meier method. Univariate predictors of the composite endpoint were hs-cTnT levels and LV dysfunction. Following a multivariate analysis, only hs-cTnT was independently associated with the events in question, either as a continuous variable (hazard ratio per unit increase in the natural logarithm: 2.83, 95% confidence interval: 1.62-4.92, P < 0.001) or as a categorical variable (hazard ratio for concentrations above the 99th percentile: 5.14, 95% confidence interval: 2.05-12.91, P < 0.001).

CONCLUSIONS: In patients with chronic refractory angina, plasma concentration of hs-cTnT is the strongest predictor of death and nonfatal MI. Notably, none of the outcomes in question occurred in patients with baseline plasma levels <5.0 ng/L.