Altered Fibrin Clot Properties Predict Stroke and Bleedings in Patients With Atrial Fibrillation on Rivaroxaban

BACKGROUND AND PURPOSE—We investigated whether clot permeability can predict clinically relevant outcomes in patients with atrial fibrillation (AF) treated with rivaroxaban. METHODS—In the cohort study, we enrolled 232 consecutive patients with AF on rivaroxaban 20 mg/d (76.3%) or 15 mg/d (23.7%) for at least 3 months. Plasma clot permeability (Ks), a measure of fibrin network density, was determined 24 to 30 hours since the intake of rivaroxaban at undetectable drug’s levels. Ischemic cerebrovascular events and bleedings were recorded. RESULTS—During a median follow-up of 48 months, patients with Ks below median (6.8 cm·10) had higher prevalence of stroke (5.84 versus 0.88% per year; P