This study is an open labeled, parallel group, and randomization study. At 7 days after mitral valve repair, bioprosthetic MV or AV replacement surgery, warfarin or edoxaban will be started per oral route. All study patients started to receive bridging therapy with parenteral anti-coagulant (UFH) according to local practice before switching to warfarin or edoxaban. Among patients who take warfarin, international normalized ratio will be used to monitor the effectiveness of the anticoagulant warfarin as usual daily practice. All patients who are assigned to VKA group, bridging with warfarin and UFH is mandatory until INR reach therapeutic target range (INR 2-3). Warfarin dose will be adjusted for maintain therapeutic range (INR 2-3) during follow up period. Patients who are randomly assigned to edoxaban group will be received 60mg qd or 30mg qd ( creatinine clearance 30-49ml/min, body weight <60kg or concomitant use of certain P-glycoprotein inhibitors). Both drugs will be maintained for 3 months. During study period, all patients will be carefully monitored for thromboembolic events including valve dysfunction, and stroke or bleeding complication. At 3 months after surgery, 3 dimensional CT scan and echocardiography will be performed for detecting valvular dysfunction, any thrombus or bleeding in heart & lung.