1.Anticoagulation indexes and requirements For patients with artificial mechanical and biological valve replacement, the INR after aortic valve replacement should be controlled within the range of 1.5-1.8, and the INR after mitral valve replacement should be controlled within the range of 1.8-2.3; if patients with biological valve replacement do not have atrial fibrillation, warfarin can be discontinued six months after surgery; conversely, regular anticoagulation therapy should be continued; patients with artificial mechanical valve replacement, regardless of whether they have atrial Patients with prosthetic mechanical valve replacement, regardless of whether they have atrial fibrillation or not, are treated with regular anticoagulation according to the above criteria. 2, monitoring requirements The INR should be monitored every 3 days at the beginning of warfarin therapy until the INR is within the target range twice in a row, and then once a week for 4 weeks, and once every 4 weeks after stabilization. The safety and effectiveness of warfarin therapy depends on maintaining the INR within the target range. Drug interactions that can enhance the effects of warfarin include: alcohol, cimetidine, steroids, fenpropidin, anti-inflammatory pain, quinidine, salicylates, methotrexate, sulfonamide, pautazone, high-dose gentamicin, thyroxine, chloral hydrate, etc. Drugs that can reduce the effect of warfarin include: vitamin K, sleeping pills, estrogen, oral contraceptives, rifampicin, cholestyramine, barbiturates, etc.