Sustained atrial fibrillation increases the risk of anticoagulation-related bleeding in heart failure.

BACKGROUND: Oral anticoagulation therapy in individuals with atrial fibrillation (AF) reduces the risk of thromboembolic events at cost of an increased bleeding risk. Whether anticoagulation-related outcomes differ between patients with paroxysmal and sustained AF receiving anticoagulation is controversially discussed.
METHODS: In the present analysis of the prospective multi-center cohort study thrombEVAL, the incidence of anticoagulation-related adverse events was analyzed according to the AF phenotype. Information on outcome was centrally recorded over 3 years, validated via medical records and adjudicated by an independent review panel. Study monitoring was provided by an independent institution.
RESULTS: Overall, the sample comprised 1089 AF individuals, of whom n = 398 had paroxysmal AF and n = 691 experienced sustained AF. In Cox regression analysis with adjustment for potential confounders, sustained AF indicated an independently elevated risk of clinically relevant bleeding compared to paroxysmal AF [hazard ratio (HR) 1.40 (1.02; 1.93); P = 0.038]. For clinically relevant bleeding, a significant interaction of the pattern of AF type with concomitant heart failure (HF) was detected: HRHF 2.45 (1.51, 3.98) vs. HRno HF 0.85 (0.55, 1.34); Pinteraction = 0.003. In HF patients, sustained AF indicated also an elevated risk of major bleeding [HR 2.25 (1.26, 4.20); P = 0.006]. A simplified HAS-BLED score incorporating only information on age (> 65 years), bleeding history, and HF with sustained AF demonstrated better discriminative performance for clinically relevant bleeding than the original version: AUCHAS-BLED: 0.583 vs. AUCsimplifiedHAS-BLED: 0.642 (P = 0.004).
CONCLUSIONS: In HF patients receiving oral anticoagulation, sustained AF indicates a substantially elevated risk of bleeding. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov , identifier: NCT01809015.