Warfarin therapy and incidence of cerebrovascular complications in left-sided native valve endocarditis

Anticoagulant therapy has been anticipated to increase the risk of cerebrovascular complications (CVC) in native valve endocarditis (NVE). This study investigates the relationship between ongoing oral anticoagulant therapy and the incidence of symptomatic CVC in left-sided NVE. In a prospective cohort study, the CVC incidence was compared between NVE patients with and without ongoing warfarin. Among 587 NVE episodes, 48 (8%) occurred in patients on warfarin. A symptomatic CVC was seen in 144 (25%) patients, with only three on warfarin. CVC were significantly less frequent in patients on warfarin (6% vs. 26%, odds ratio OR] 0.20, 95% confidence interval CI] 0.06–0.6, p = 0.006). No increase in haemorrhagic lesions was detected in patients on warfarin. Staphylococcus aureus aetiology (adjusted OR aOR] 6.3, 95% CI 3.8–10.4) and vegetation length (aOR 1.04, 96% CI 1.01–1.07) were risk factors for CVC, while warfarin on admission (aOR 0.26, 95% CI 0.07–0.94), history of congestive heart failure (adjusted OR 0.22, 95% CI 0.1–0.52) and previous endocarditis (aOR 0.1, 95% CI 0.01–0.79) correlated with lower CVC frequency.