Iliofemoral venous configurations from three-dimensional computed tomography venogram and their relevance to stent design

Objective: Iliofemoral venous stenting has become the standard of care for patients presenting with quality-of-life impairing symptoms of chronic iliofemoral venous obstruction not responding to conservative measures. This has led to an increased use of venous stenting over the last several years. However, iliofemoral venous anatomy in patients requiring such intervention remains poorly elucidated. This study attempts to fill that gap. Methods: Twenty-two consecutive patients with intravascular ultrasound examination-confirmed chronic iliofemoral venous obstruction underwent three-dimensional reconstruction of their computed tomography venogram images. Relevant angles, tortuosity (tort index-ratio between centerline length, and straight line length), lengths, and diameters were computed and analyzed. We used t tests for comparisons between the right and left sides. A P value of .05 or less was considered significant. Results: Of the angles calculated, the median of the angles between the horizontal and common iliac vein (CIV) was 66 degrees on the right and 60 degrees on the left (P < .01). The median inferior vena cava-CIV angle was 172 degrees on the right and 165 degrees on the left (P < .0001). The CIV-EIV angle was 159 degrees on the right and 151 degrees on the L (P = .01). Overall, the median tortuosity was 1.07 on the right and 1.12 on the left (P = .007). The median centerline length of the CIV was 42mm on the right and 60mm on the left (P < .0001). The median external iliac vein length was 73 mm on the right and 88 mm on the left (P < .0001). The overall median iliac vein length was 220 mm on the right and 237 mm on the left (P < .01). The median diameters of the inferior vena cava at the iliocaval confluence, 20, 40, and 60 mm cranial to the confluence, were 23, 20, 22, and 23 mm, respectively. Conclusions: Overall, the left side has steeper angles, greater tortuosity, and longer lengths than the right side. These disparities should be considered during femoroiliocaval stent construction.