A detailed analysis of equivocal duplex findings in patients with suspected deep venous thrombosis.

OBJECTIVE: To analyze equivocal duplex findings in patients with clinically suspected deep venous thrombosis and thus to increase the diagnostic utility of color duplex sonography in this category of patients. METHODS: Phlebography was requested in a series of 102 consecutive patients with inconclusive duplex findings. These patients were, according to the duplex findings only, subdivided into having low, intermediate, and high probability of deep venous thrombosis. RESULTS: Phlebographywas attempted in 71 cases and successfully performed in 49. The remaining 53 patients were prospectively followed clinically for 6 months. Phlebography showed deep venous thrombosis in 1 of 63 patients in the group with low probability, 3 of 31 in the intermediate group, and all of the 8 patients with high probability. Twenty-two (31%) of the 71 attempted phlebographic examinations were nondiagnostic. None of the patients in the follow-up group had any thromboembolic complications. CONCLUSIONS: Even if a duplex examination is equivocal, it is still possible to extract clinically useful information by categorizing the duplex results into subgroups with low, intermediate, and high probability of deep venous thrombosis. This can have implications for the diagnostic or therapeutic handling of these patients and thus can increase the utility of sonography in patients with inconclusive duplex findings.

Is it safe to withhold anticoagulation based on a single negative color duplex examination in patients with suspected deep venous thrombosis? A prospective 3-month follow-up study.

The aim of this study was to evaluate prospectively the clinical short-term outcome of patients with suspected deep venous thrombosis (DVT) and negative duplex investigation and to assess whether it is clinically safe to withhold anticoagulant therapy on the basis of a single negative color duplex examination including the calf veins. The study included a consecutive series of patients with suspected DVT referred for color duplex examination over 1 year. Patients with negative duplex findings (n = 341) were followed up for 3 months clinically and/or by reviewing hospital charts and the official registry of health care and causes of death. In only 1 of the patients was DVT diagnosed following a negative duplex examination. This patient had accentuated symptoms and a thrombus in the peroneal vein was detected at subsequent phlebography. None of the other patients with a negative duplex finding developed signs of, or had treatment initiated for, DVT or pulmonary embolism during the 3-month period after the duplex investigation. Five patients died, but none of the deaths was related to thromboembolism. The results indicate that it is clinically safe to rely on a single negative color duplex examination in patients without any progressing symptoms from the affected limb.