The role of venous ultrasonography in the diagnosis of suspected deep venous thrombosis and pulmonary embolism

This paper describes the role of venous ultrasonography in the diagnosis of suspected deep venous thrombosis and pulmonary embolism. Inability to comp ress the common femoral or popliteal vein is usually diagnostic of a first episode of deep venous thrombosis in symptomatic patients (positive predict ive value of about 97%). Full compressibility of both of these sites exclud es proximal deep venous thrombosis in symptomatic patients (negative predic tive value of about 98%). In patients with suspected deep venous thrombosis or in those who present with suspected pulmonary embolism but have a nondi agnostic lung scan, the subsequent risk for symptomatic venous thromboembol ism is very low (<2% during 6 months of follow-up) provided that ultrasonog raphy of the proximal veins remains normal in the course of 1 week (suspect ed deep venous thrombosis) or 2 weeks (suspected pulmonary embolism). Antic oagulation and further diagnostic testing can usually be safely withheld in these situations. Venous ultrasonography is much less reliable for the dia gnosis of asymptomatic, isolated distal, and recurrent deep venous thrombos is than for the diagnosis of a first episode of proximal deep venous thromb osis in symptomatic patients. Clinical evaluation of the probability of dee p venous thrombo!;is or pulmonary embolism, preferably by using a validated clinical model, complements venous ultrasonographic findings and helps to identify patients who would benefit from additional (often invasive) diagno stic testing. Thus, venous ultrasonography is thought to be a very valuable test for the diagnosis and management of patients with suspected deep veno us thrombosis or pulmonary embolism.