What is the benefit of anticoagulation in reducing the risk of stroke or systemic embolism in AF?
Anticoagulation decreases thrombus formation systemically, including the left atrium, and reduces the risk of stroke or systemic embolism in AF, but at the cost of increased bleeding. VKA with warfarin reduced the primary event rate in the randomized SPAF trial (Stroke Prevention in Atrial Fibrillation Study) by 67% (7.4% to 2.3%) and was superior to treatment with aspirin alone, which reduced the primary event rate by 42%. Four DOACs apixaban, dabigatran, edoxaban, and rivaroxaban have been studied in 4 large randomized trials against VKA with consistent evidence of noninferior reduction in thromboem- bolic risk and reduced bleeding risk. All trials of DOACs specifically excluded patients with valvular AF; however, up to 20% of patients in these trials had some degree of valvular heart disease (VHD). 