Is bilateral ultrasound scanning of the legs necessary for patients with unilateral symptoms of deep vein thrombosis?

Purpose: The purpose of this study was to determine the necessity of bilate ral lower-extremity venous duplex ultrasound scanning in patients with unil ateral symptoms of deep vein thrombosis (DVT). Patients and Methods: A retrospective review of 1080 bilateral venous duple x scans was performed. Patients were randomly selected from a total of 7922 studied between May 1998 and May 2000. Data on patient age, sex, comorbidi ty, and the reason for ultrasound scan were compiled. Forty percent (435/10 80) of patients presented with unilateral symptoms of lower-extremity DVT. This group was further analyzed according to their status as inpatients or outpatients. Results. DVT was diagnosed in 26.9% (117/435) of the patients. Of the inpat ients found to have DVT, the thrombus was confined to the symptomatic leg i n 23.8% (38/159), thrombus was present just in the asymptomatic leg in 8/15 9 (5.0%), and thrombus was found in both legs in 8/159 (5.0%). In the outpa tient group, thrombus was confined to the symptomatic leg in 21.0% (58/276) and found in both legs in 1.8% (5/276). None of the 276 outpatients had DV T isolated in the asymptomatic leg. Conclusion: Routine bilateral lower-extremity venous duplex studies are not necessary in outpatients presenting with unilateral symptoms. In many outp atients, a single-limb study will suffice. If a patient is found to have a DVT on the symptomatic side, then we believe that a bilateral study is indi cated. We do believe that routine bilateral scanning of inpatients remains justified. This algorithm may save technician time and increase vascular la boratory efficiency.