Venous thromboembolic disease: diagnosis and use of antithrombotic therapy.

Several invasive and noninvasive tests are available to aid the clinician in the diagnosis of deep venous thrombosis and pulmonary embolism. Contrast venography remains the standard for diagnosing deep venous thrombosis of the lower extremity, while impedance plethysmography is sensitive, specific, and noninvasive. Compressive duplex ultrasonography is useful for deep venous thrombosis of the thigh down to the popliteal vein. The ventilation-perfusion lung scan is the most common test for diagnosing pulmonary embolism, but pulmonary angiography remains the standard. Heparin is the mainstay of treatment for deep venous thrombosis and pulmonary embolism, with an important role played by warfarin therapy.