Anticoagulation: indications and risk classification schemes.

Anticoagulation is an important component of the management strategy for several common medical conditions. It is indicated for the prevention of recurrent thrombosis in patients with venous thromboembolism (VTE), which includes deep venous thrombosis and pulmonary embolism, and ischemic stroke. Many surgical procedures also put patients at increased risk of VTE. Patients undergoing major orthopedic surgery should receive short-term anticoagulation. The Caprini Risk Assessment Model score can be used to estimate VTE risk and guide anticoagulation therapy recommendations for most nonorthopedic surgical patients. For patients with atrial fibrillation, assessment with the CHADS2 (Congestive heart failure, Hypertension, Age at least 75 years, Diabetes, previous Stroke or transient ischemic attack) score or a similar risk score is used to guide the decision on anticoagulation for stroke prevention. Anticoagulation also is used to prevent VTE in nonsurgical hospitalized patients at increased risk because of immobility or other factors. Patients with acute coronary syndrome should receive short-term anticoagulation. For patients with VTE in whom a reversible risk factor is identified, anticoagulation can be discontinued after 3 months. All patients with mechanical heart valves should receive lifelong anticoagulation.