Prognosis in patients with atrial fibrillation and CHA2DS2-VASc Score = 0 in a community-based cohort study.

Objectives: Patients with atrial fibrillation (AF) and a CHA(2) DS(2) -VASc score = 0 have a very low risk of stroke and current guidelines even recommend no antithrombotic therapy to these patients. We investigated the rate and risk of adverse events and the impact of antithrombotic management in a community based cohort of AF patients with a CHA(2)DS(2)-VASc score = 0.

Methods And Results: Patients with AF seen in our institution between 2000 and 2010 were identified in a database. The adverse outcomes were investigated during follow-up. Among 8,962 patients with AF, 616 (7%) had a congestive heart failure, hypertension, age ≥75 years (doubled), diabetes, stroke/TIA/thromboembolism (doubled), vascular disease (prior myocardial infarction, peripheral artery disease, or aortic plaque), age 65-74 years, sex category (female) (CHA(2)DS(2)-VASc score) = 0. An oral anticoagulant was prescribed in 273 patients (44%), antiplatelet therapy alone in 145 patients (24%), and no antithrombotic treatment in 198 patients (32%). During a follow up of 876 ± 1,135 days (median 244, interquartile range 1,540 days), 38 patients sustained events (10 stroke/thromboembolism, 19 major bleeding, 17 deaths). Among untreated patients, rates of stroke/thromboembolism, major bleeding and mortality were 0.64%, 1.12%, and 1.08% per year. Prescription of oral anticoagulation and/or antiplatelet therapy was not associated with an improved prognosis for stroke/thromboembolism (relative risk [RR] = 0.99, 95% CI 0.25-3.99, P = 0.99), nor improved survival or net clinical benefit (combination of stroke/thromboembolism, bleeding, and death).

Conclusion: In a real life cohort study, AF patients with CHA(2)DS(2) VASc score = 0 had a low risk of stroke/thromboembolism that was not significantly different between those taking oral anticoagulation, antiplatelet therapy, or no antithrombotic therapy. This supports current guideline recommendations for no antithrombotic therapy in these "truly low-risk" patients.