Management of Stroke Prevention in Canadian Patients with Atrial Fibrillation at Moderate to High Risk of Stroke

Abstract

Many patients with atrial fibrillation who are at moderate to high risk of stroke do not receive anticoagulation with vitamin K antagonists (VKAs) in accordance with recommendations. To determine (1) why Canadian patients with atrial fibrillation who are potentially eligible for VKA do not receive this therapy, (2) why Canadian primary care physicians discontinue VKA therapy, and (3) why VKA therapy is perceived as difficult to manage. The study involved a chart review of 3 cohorts of patients with nonvalvular atrial fibrillation at moderate to high risk of stroke: patients who had never received VKA treatment (VKA-naive), those whose treatment had been discontinued, and those whose VKA treatment was considered difficult to manage. Charts for 187 patients (mean age 78.4 years, standard deviation 8.9 years) treated at 39 primary care sites were reviewed (62 treatment-naive, 42 with therapy discontinued, and 83 whose therapy was considered difficult to manage). Atrial fibrillation was paroxysmal in 82 (44%) of the patients, persistent in 47 patients (25%), and permanent in 58 (31%). One patient in each of the 3 cohorts had experienced a stroke during the 6 months before study participation. Bleeding events were more frequent among patients who had discontinued VKA therapy than in the other 2 groups. Among those whose therapy was discontinued and those whose therapy was difficult to manage, the mean time in the therapeutic range was 46.3% and 56.4%, respectively. The most common reason for not initiating VKA therapy in treatment-naive patients was the transient nature of atrial fibrillation (25/62 [40%]). The most common reason for discontinuation of VKA therapy was a bleeding event (10/42 [24%]). The presence of a concomitant chronic disease was the most common reason that a patient's therapy was considered difficult to manage (46/83 [55%]). VKA therapy was not initiated or was discontinued for various reasons. Multiple comorbid conditions made management of VKA therapy more difficult. These findings reflect the challenges that primary care physicians experience in managing the care of patients with atrial fibrillation.