Importance of Persistent Elevation of Cardiac Biomarkers in Atrial Fibrillation: A RE-LY Substudy

Study Questions:

Do cardiac troponin-I or N-terminal-B-type natriuretic peptide (BNP) have prognostic significance in patients with atrial fibrillation (AF)?

Methods:

Troponin and BNP plasma levels were measured at baseline and 3 months of follow-up in 2,514 patients with AF and ≥1 risk factor for stroke. This was a prospective substudy of a randomized trial comparing warfarin and dabigatran for stroke prevention. Median follow-up was 2 years. The patients were grouped according to whether troponin was never detectable (Group 1), detectable at one of two time points (Group 2), or detectable at both time points (Group 3). They also were grouped according to whether BNP was lower than the median value (778 ng/L) at both time points (Group 1), one of two time points (Group 2), or neither time point (Group 3).

Results:

Troponin was detectable at both time points in 48.5% of patients and at neither time point in 21%. The annual stroke/embolism rate for troponin groups 1, 2, and 3 were 0.67%, 0.77%, and 1.96%, respectively. The annual stroke/embolism rates for BNP groups 1, 2, and 3 were 1.11%, 0.55%, and 1.87%, respectively. Persistent elevation of either biomarker was independently associated with a higher risk of cardiovascular events and death.

Conclusions:

The authors concluded that persistent elevation of troponin or BNP in patients with AF is independently associated with a higher risk of stroke and mortality.

Perspective:

Prior studies have demonstrated that biomarkers such as troponin and BNP measured at one point in time are associated with worse outcomes in patients with AF. This is the first study to show that serial measurements improve the prognostic value of these biomarkers compared to single measurements.

Keywords: Stroke, beta-Alanine, Benzimidazoles, Troponin I, Warfarin, Risk Factors, Embolism, Natriuretic Peptide, Brain


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