This patient should continue taking warfarin. She has a history of symptomatic atrial fibrillation and is now symptom-free without evidence of recurrent atrial fibrillation after catheter ablation. However, patients with successful ablation and elimination of symptoms may have transient asymptomatic atrial fibrillation with continued risk for atrial fibrillation–associated thromboembolic disease. Therefore, current consensus recommendations counsel that stroke prevention therapy following atrial fibrillation ablation be based on risk factors and not rhythm status, with the preferred risk stratification tool being the CHA₂DS₂-VASc risk score, which has improved predictive ability relative to the CHADS₂ score. The patient is a 58-year-old woman with a prior transient ischemic attack (TIA) and hypertension. Accordingly, her CHA₂DS₂-VASc risk score is 4 (2 points for TIA, 1 point for hypertension, and 1 point for female sex). Current guidelines advocate oral anticoagulation for any patient with nonvalvular atrial fibrillation and a CHA₂DS₂-VASc score greater than 1. She has a history of a central nervous system event, and her annual risk of stroke is high (greater than 5% annually). Therefore, she should be continued on anticoagulation with warfarin.

Concomitant aspirin therapy with warfarin is reserved for patients with active coronary artery disease. This patient has risk factors for atherosclerosis, but she does not have a history of coronary artery disease or acute coronary syndromes. The addition of aspirin to warfarin significantly increases the risk of bleeding.

Discontinuation of warfarin and substitution with aspirin or dual antiplatelet therapy is not correct. Aspirin is insufficient therapy for a patient at high risk of stroke. The Atrial fibrillation Clopidogrel Trial with Irbesartan for prevention of Vascular Events (ACTIVE-W) trial compared warfarin with therapy with aspirin and clopidogrel and found that aspirin with clopidogrel was inferior to warfarin for stroke prevention with no statistically significant difference in bleeding.

Anticoagulation with a novel oral anticoagulant (such as dabigatran, rivaroxaban, or apixaban) could be considered; however, these agents have been associated with increased gastrointestinal bleeding compared with warfarin.