Prognostic value of biomarkers during and after non-ST-segment elevation acute coronary syndrome.

OBJECTIVES: The aim of this study was to assess risk prediction by different biomarkers in patients with an ongoing non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and after clinical stabilization.

BACKGROUND: Different biomarkers reflect different aspects of the pathobiology in NSTE-ACS. However, there is little information regarding their relative prognostic value during the time course of disease.

METHODS: The N-terminal pro-brain natriuretic peptide (NT-proBNP), C-reactive protein (CRP), cardiac troponin I (cTnI), and the estimated glomerular filtration rate (eGFR) were measured at randomization and after 6 weeks and 6 months in 877 NSTE-ACS patients included in the FRISC (FRagmin and fast revascularization during InStability in Coronary artery disease) II trial. The biomarkers' prognostic value during 5-year follow-up was evaluated by Cox regression models, calculation of the c-statistics, and estimation of the net reclassification improvement (NRI).

RESULTS: Among the biomarkers measured at randomization, NT-proBNP was the strongest predictor for mortality (adjusted hazard ratio [HR]: 1.7; 95% confidence interval [CI]: 1.3 to 2.1; p < 0.001). Even during follow-up, NT-proBNP demonstrated the strongest association to the composite end point of death/myocardial infarction (adjusted HR at 6 weeks: 1.5; 95% CI: 1.3 to 1.7; p < 0.001; adjusted HR at 6 months: 1.4; 95% CI: 1.2 to 1.7; p = 0.001). Even CRP was independently predictive at 6 months for the composite end point (adjusted HR: 1.3; 95% CI: 1.1 to 1.5; p = 0.003). Only 6-week results of NT-proBNP provided significant incremental prognostic value to established risk indicators regarding the composite end point (c-statistics 0.69 [p = 0.03]; NRI 0.11 [p = 0.03]).

CONCLUSIONS: The NT-proBNP is an independent risk predictor in patients with ongoing NSTE-ACS and after clinical stabilization. The CRP exhibits increasing predictive value at later measurements. However, only NT-proBNP provided incremental prognostic value and might therefore be considered as a complement for early follow-up controls after NSTE-ACS.