Abstract 14808: Importance of Persistent Elevation of Cardiac Biomarkers in Atrial Fibrillation - A RELY Substudy

Abstract

Background: Cardiac troponin I (cTnI) and N-terminal-B-type natriuretic peptide (NT-proBNP) predict poor prognosis in atrial fibrillation (AF) patients. However, it is not known whether transient or persistent elevations of the biomarkers have differing prognostic importance. In this study we investigate if serial measures of biomarkers improve the prognostic information in AF patients.

Methods: Plasma samples were obtained at randomization and at 3 months in 2508 AF patients in the RE-LY trial. Patients were grouped based on levels at the 2 time points according to positive cTnI levels (≥0.01 ug/L) or NT-proBNP levels above median (≥778 ng/L). Serial cTnI and NT-proBNP concentrations in relation to stroke or systemic embolism (SE) and a composite thromboembolic endpoint (ischemic stroke, systemic embolism, myocardial infarction, pulmonary embolism, and vascular death (excluding hemorrhagic death)) were evaluated with Cox models adjusting for established cardiovascular risk factors.

Results: The proportion of patients with positive cTnI levels at both time points was 48.5%, at one time point 28.5% and at neither time point 21.0%. During a median 2.0 years follow-up patients with a positive cTnI at both time points had a significantly higher risk of stroke or SE compared to those with transient elevations, and those with no elevation at either time point. The findings for NT-proBNP did not reach statistical significance for stroke or SE. Elevation of both cardiac biomarkers at baseline and 3 months was associated with the highest risk for stroke or SE. Serial measurements of cardiac biomarkers in relation to the composite thromboembolic endpoint yielded similar results and identified the highest risk group when combined (p<0.0001).

Conclusion: Persistent elevation of troponin and NT-proBNP indicate a worse prognosis than transiet elevations or no elevations of either marker. Prognostic prediction is improved by the use of serial measures of biomarkers.