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Ruling Out DVT and PE Without Imaging

The search continues for ways to simplify the diagnosis of venous thromboembolic disease. Two studies provide data on the utility of D-dimer testing and clinical judgment.

Canadian researchers used a 9-item checklist supplemented by clinical judgment to determine whether outpatients with suspected first episodes of deep vein thrombosis (DVT) had low, moderate, or high pretest probabilities of DVT. Whole-blood D-dimer was determined for all patients. Of 445 patients, 206 (48 percent) were thought to have low pretest probabilities of DVT; 177 (40 percent of all patients) also had negative D-dimer tests and were not treated with anticoagulants. After 3 months, only 1 of these 177 patients developed symptomatic DVT (an isolated thrombosis of the calf).

Similarly, another research group studied 930 emergency department patients with suspected pulmonary embolism; 437 patients had negative D-dimer tests and low pretest probabilities as determined using a clinical model that incorporated several variables (e.g., signs and symptoms of DVT, tachycardia) and clinical judgment. Anticoagulation was withheld in these patients, 3 of whom had pulmonary embolism (2 diagnosed on the day of presentation by high-probability lung scans done outside the research protocol, and 1 during follow-up).

Comment: Imaging can be avoided safely in a significant minority of outpatients with suspected pulmonary embolism or deep vein thrombosis. The success of this clinical strategy depends on determining a pretest probability, using a sensitive D-dimer assay, and limiting the strategy to outpatients, who have a relatively low chance (< 10 percent) of having thromboembolism to begin with.

— R Saitz

Published in Journal Watch General Medicine August 14, 2001

Citation(s):

Kearon C et al. Management of suspected deep venous thrombosis in outpatients by using clinical assessment and D-dimer testing. Ann Intern Med 2001 Jul 17 135 108-111.

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• Medline abstract (Free)

Wells PS et al. Excluding pulmonary embolism at the bedside without diagnostic imaging: Management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and D-dimer. Ann Intern Med 2001 Jul 17 135 98-107.

• Original article (Subscription may be required)
• Medline abstract (Free)