Intravenous vitamin K can be given, but carries a risk of anaphylaxis. Warfarin therapy for most conditions requires a target INR of 2.0 - 3.0. Perioperative DVT prevention Patients with history of DVT or undergoing major orthopedic procedure. DVT Heparin for 5 to 10 days then warfarin for 3 to 6 months. If risk of bleeding is high, INR can be reduced to 2.0 - 3.0.
Warfarin is given for the first three postoperative months.
Non-valvular atrial fibrillation Warfarin for patients over the age of 60 or with associated cardiac abnormality. Mitral valve prolapse Warfarin only for cases complicated by embolic history or atrial fibrillation. Rheumatic mitral valve disease Warfarin is used for patients with very large left atria, history of systemic embolism, or atrial fibrillation. Dilated cardiomyopathy Warfarin prophylaxis is reasonable, but not backed by randomized trial data. Bleeding complications are increased with INR of 3.5 - 4.5, age over 65, therapeutic aspirin treatment, prior stroke or GI bleeding, chronic renal failure, chronic anemia, and occult GI or GU neoplasm.