Iliofemoral venous thrombosis: real-time ultrasound diagnosis, normal criteria, and clinical application.

We determined the response of the common femoral vein to respiratory maneuvers using high resolution real-time ultrasound in 10 normal subjects, and we evaluated this modality in the diagnosis of iliofemoral venous thrombosis in 36 patients. We developed diagnostic criteria for assessment of the venous system and have confirmed them with phlebography or pathologic findings. An increase in venous diameter of 50-200% on performance of the Valsalva maneuver, with a prompt return to the original configuration, was always associated with a normal iliofemoral venous system. Two patterns of occlusion of the femoral venous system were found: an enlarged circular femoral vein that did not increase in size on deep inspiration or performance of the Valsalva maneuver, and difficulty or inability to detect the common femoral vein. A dampened response, i.e., a 10-50% diameter increase on performance of the Valsalva maneuver, was associated with deep vein thrombosis in four of six patients. The false positive rate of 8% was due to gross congestive cardiac failure in one patient. This technique is simple to perform, relatively inexpensive, expeditious, and has proved useful in confirming or denying the presence of iliofemoral venous thrombosis.