A 72-year-old woman with hypertension, diabetes, and heart failure with reduced ejection fraction presents with palpitations and dyspnea. ECG shows atrial fibrillation with an irregularly irregular rhythm. Echocardiogram reveals nonvalvular AF. Her CHA2DS2-VASc score is 5. She has normal renal function and no history of major bleeding. Which is the most appropriate long-term strategy for stroke prevention?