PS166. Role of Intravenous Ultrasound in Assessment of Iliac-Femoral Vein Stenosis

Lower extremity venous stasis disease could be related to outflow obstruction in the iliac-femoral vein segments due to stenosis or extrinsic compression. Conventional methods to assess these vein segments include trans-cutaneous ultrasonography and ascending venography. The trans-cutaneous approach has a low sensitivity, and venography can miss significant lesions as the assessment is undertaken in a single view. We wanted to assess the role of Intravenous ultrasound (IVUS) in detecting the location as well as the degree of stenosis in the iliac-femoral vein segments. 104 patients with chronic lower extremity venous stasis disease were evaluated for outflow obstruction/stenosis with ascending venography and IVUS. The location and degree of any stenosis were noted. A significant stenosis was defined as a 50% reduction in the diameter of the vein relative to the adjacent vein segments. Patients with significant stenosis underwent venous stenting to restore outflow. The results of venography and IVUS were then compared. 46 (44.2%) patients had no evidence of stenosis on either venography or IVUS and hence received no stents. 58 (55.8%) patients were note to have significant stenotic lesions on IVUS. Among those, 10 (17.2%) patients had no detectable lesion on venogram and would have been missed. In 24 (41.4%), venography failed to identify all stenotic lesions or resulted in in-accurate localization of the lesion. Only 24 (41.4%) patients had stenotic lesions on venogram that conformed anatomically to the lesions detected on IVUS. In assessing patients with lower extremity venous stasis disease for iliac-femoral vein stenosis/obstruction, venography alone can result in poor localization (50% specificity) and can even miss significant stenotic lesions (82.8% sensitivity). IVUS is a more sensitive and accurate method, and should be included in all such evaluations.