Summary

Diagnosis of recurrent deep-vein thrombosis (DVT) is difficultbecause of limitations in distinguishing acute from old thrombi. In thepast, an ultrasound method for diagnosis of recurrent ipsilateral DVTwas developed, which relies on repeated measurements of the diametersof the common femoral and popliteal veins. To assess the safetyof withholding anticoagulation from patients with improved or stablecompression vein diameters, 205 consecutive patients presenting withsuspected recurrent ipsilateral DVT were evaluated. The vein diameterwas measured under compression with the transducer and comparedwith earlier ultrasound results. Patients with stable or improved ultrasoundfindings had repeat ultrasound assessments after 2 (± 1) and7 (± 1) days. Patients with repeatedly normal ultrasound results werefollowed-up for six months to determine the incidence of symptomaticrecurrent venous thromboembolism.Of the 205 patients, 153 had stable or improved ultrasound findings.Repeat ultrasound assessment became abnormal in 3, and recurrencewas confirmed by venography in all. A six months follow-up wasdone in the remaining 150 patients with repeatedly normal ultrasoundtests and showed 2 (1.3%; 95% CI, 0.02 to 4.7%) confirmed non-fatalvenous thromboembolic complications. The positive predictive valueof a stable or improved ultrasound was 90% (95% CI, 77 to 97%).In conclusion, it is safe to withhold anticoagulant treatment from patientswith suspected recurrent ipsilateral DVT in whom compressionultrasonography showed improved or stable vein diameters.