ASA indicates aspirin; AVR, aortic valve replacement; INR, international normalized ratio; MVR, mitral valve replacement; VKA, vitamin K antagonist; Rx, medication; and TAVI, transcatheter aortic valve implantation. CLINICAL STATEMENTS AND GUIDELINES study, patients with a bioprosthetic mitral valve replacement who received anticoagulation had a lower rate of thromboembolism than that of those who did not receive therapy with VKA.15 Even with routine anticoagulation early after mitral valve surgery, the incidence of ischemic stroke within the first 30 postoperative days was higher after replacement with a biological pros- thesis than after mitral valve repair (1.5% 0.4%) or replacement with a mechanical prosthesis.21 Small studies have not established a convincing net benefit of anticoagulation after implantation of a bioprosthetic AVR24,25 ; however, a large obser- vational Danish registry demonstrated a lower risk of stroke and death with VKA, which extended up to 6 months, without a significantly increased Concern has been raised about the incidence of subclinical bioprosthetic valve leaflet thrombosis after surgical valve replace- In addition, the PARTNER 2 (Placement of Aortic Transcatheter Valves) investigators reported that the use of anticoagulation after bioprosthetic AVR in intermediate or higher sur- gical risk patients was safe and associated with a significant reduction in 6-month stroke rates.23 Ninety-five percent of the anticoagulated patients in this registry were discharged on warfarin in preference to a direct oral anticoagulant. 8. The prior recommendation to add low-dose aspi- rin to therapeutic VKA therapy for a mechanical valve prosthesis was based on studies performed decades ago that included many patients with older-generation prostheses who also had addi- tional thromboembolic and vascular risk factors. 