CT Study of the Relationship Between the Common Iliac Artery and Vein and Their Juxtaposition: Implications for Conduit Construction Prior to Endosvascular Stent-Graft Repair of Aortic Aneurysms

The objective of this study was to determine the anatomical relationship and juxtaposition between the common iliac artery and vein in a population of patients with aortic aneurysmal disease and a population clinically and radiologically free of atheroma. It was a retrospective study of 100 consecutive patients undergoing computed tomographic assessment of abdominal aortic aneurysm prior to endovascular or open surgical repair and 100 patients undergoing computed tomographic assessment for other pathologies who did not have clinical or imaging signs of aorto-iliac atheroma. In both groups the anatomical relationship between the right and left iliac artery and vein was studied, and the thickness of the fat plane separating the artery from the vein measured. The right iliac vein was posterolateral to the artery at the level of the common iliac artery bifurcation in 95% of patients in both groups. At the same level the left iliac vein was posterior in 23% (p ≤ 0.001). Eighty-three percent of patients in the aneurysm group had a fat plane between the right artery and vein that measured 0 mm (no visible fat plane = 52%) to 1 mm (= 31%). Ninety-eight percent of patients in the aneurysm group had a measurable fat plane between the left iliac artery and vein of up to 5 mm (p = 0.001). Six percent of the control group demonstrated no visible fat plane between the right iliac artery and vein (p ≤ 0.001), while the fat plane measured more than 1 mm (1–5 mm) on the left in 100%. We conclude that in patients where conduit construction is required for aortic stent-graft access, the anatomical configuration and intimate relationship of the iliac arteries and veins should be assessed and taken into account at CT scan evaluation. The distal right common iliac artery should not be used, as venous damage can be predicted from the anatomical and intimate relationship of the iliac artery and vein at this level in patients with atheroma and the difficulties this relationship presents if venous repair is necessary.