Assessment of the patency of deep leg veins with duplex

To evaluate the accuracy of venous duplex, results obtained in 101 patients are compared with venography. A first group consisted of 48 patients with clinically suspected deep vein thrombosis. In 30 of them a positive duplex scan was obtained and all had subsequently a positive venography. Eighteen patients with a normal duplex scan had a normal venography. Another group of 53 patients were tested preoperatively for varicose vein surgery. No obstruction of the venous system was withheld with duplex but 3 patients had an old thrombosis on venography. Thus duplex is a highly reliable method to detect proximal thrombosis in clinically suspected patients but detection of late sequelae of thrombosis may be more difficult.