Cardiac biomarkers and left ventricular hypertrophy in relation to outcomes in patients with atrial fibrillation: Experiences from the RE-LY trial

Background Cardiac biomarkers and left ventricular hypertrophy (LVH) are related to the risk of stroke and death in patients with atrial fibrillation. We investigated the interrelationship between LVH and cardiac biomarkers and their independent associations with outcomes. Methods and Results Plasma samples were obtained at baseline in 5275 patients with atrial fibrillation in the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial. NT-proBNP (N-terminal pro-B-type natriuretic peptide), cardiac troponin I and T, and growth differentiation factor-15 were determined using high-sensitivity (hs) assays. LVH was defined by ECG. Cox models were adjusted for baseline characteristics, LVH, and biomarkers. LVHwas present in 1257 patients. During a median follow-up of 2.0 years, 165 patients developed a stroke and 370 died. LVHwas significantly (P<0.0001) associated with higher levels of all biomarkers in linear regression analyses adjusting for baseline characteristics. Geometric mean ratios (95% CIs) were as follows: NT-proBNP, 1.32 (1.25-1.38); hs cardiac troponin I, 1.67 (1.57-1.78); hs troponin T, 1.38 (1.32-1.44); and growth differentiation factor-15, 1.09 (1.05-1.12). For stroke, the hazard ratios (95% CIs) per 50% increase were as follows: NT-proBNP, 1.09 (1.00-1.19); hs cardiac troponin I, 1.09 (1.03-1.15); hs troponin T, 1.14 (1.06-1.24); and growth differentiation factor-15, 1.22 (1.08-1.38) (all P<0.05). For death, hazard ratios (95% CIs) were as follows: NT-proBNP, 1.24 (1.17-1.31); hs cardiac troponin I, 1.13 (1.10-1.17); hs troponin T, 1.28 (1.23-1.34); and growth differentiation factor-15, 1.31 (1.22-1.42) (all P<0.0001). LVH was not significantly associated with stroke or death after adjustment for biomarkers. Conclusions Cardiac biomarkers are significantly associated with LVH. The prognostic value of biomarkers for stroke and death is not affected by LVH. The prognostic information of LVH is attenuated in the presence of cardiac biomarkers.