Principles of Antithrombotic and Fibrinolytic Therapy

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), occurs in approximately 2–3 per 1000 person-years among adults in the United States, with an estimated 60,000–100,000 deaths per year. DVT refers to thrombosis involving deep veins, including popliteal, femoral, and iliac veins of lower extremity and brachial, axillary, subclavian, and brachiocephalic veins of upper extremity. Proximal DVT involves the popliteal or more proximal veins, whereas distal (below the knee) DVT involves vessels distal to the trifurcation of the popliteal vein. Massive PE is defined as any PE that causes hemodynamic instability with systemic arterial hypotension. Submassive PE is associated with evidence of right ventricular dysfunction without systemic hypoten sion.