Thrombosed Björk-Shiley mitral prostheses.

2008 Focused Update Incorporated Into the ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease

“…Patients at high risk of thrombosis include all patients with mechanical mitral or tricuspid valve replacements and patients with an AVR and any risk factors. Such risk factors include atrial fibrillation, previous thromboembolism, hypercoagulable condition, oldergeneration mechanical valves, LV dysfunction (ejection fraction less than 0.30), or more than 1 mechanical valve (971)(972)(973). When UFH is used, it should be started when INR falls below 2.0 (i.e., 48 h before surgery) and stopped 4 to 6 h before the procedure.…”

ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease

“…Such risk factors include atrial fibrillation, previous thromboembolism, hypercoagulable condition, older-generation mechanical valves, LV dysfunction (ejection fraction less than 0.30), or more than 1 mechanical valve (971)(972)(973). When UFH is used, it should be started when INR falls below 2.0 (i.e., 48 h before surgery) and stopped 4 to 6 h before the procedure.…”

2008 Focused Update Incorporated Into the ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease

“…Such risk factors include atrial fibrillation, previous thromboembolism, hypercoagulable condition, older-generation mechanical valves, LV dysfunction (ejection fraction less than 0.30), or more than 1 mechanical valve. [971][972][973] When UFH is used, it should be started when INR falls below 2.0 (i.e., 48 h before surgery) and stopped 4 to 6 h before the procedure. UFH should be restarted as early after surgery as bleeding stability allows, and the aPTT should be maintained at 55 to 70 s until warfarin is therapeutic.…”