Distal Iliac Neck Evolution After EVAR With Trivascular Ovation Stent Graft: Midterm Results From the Italian Registry

Objectives As opposed to the proximal aortic neck, distal iliac neck evolution after endovascular repairs (EVAR) has not been addressed adequately in the literature. With a core laboratory analysis of morphological changes, this study evaluated midterm results of distal iliac neck evolution after EVAR with the Trivascular Ovation stent graft. Methods This was a multicenter registry of all patients undergoing EVAR with a Trivascular Ovation endograft. Inclusion criteria were the availability of computed tomography (CT) images at a minimum follow-up of 24 months. Standard CT scans were reviewed centrally using dedicated software. Distal common iliac neck was segmented into zone A, called bifurcation area (within 5 mm to the hypogastric bifurcation); zone B, called landing area (at the level of the iliac limb landing). Images were analyzed for iliac neck enlargement (≥2 mm), proximal graft migration (GM; ≥5 mm), patency, and endoleak. Iliac-related outcome and iliac-related secondary reintervention (IRSI) were reported. Data were further stratified in case of ectatic common iliac artery (CIA, diameters >15 mm). Results Inclusion criteria were met by 89 patients. Technical success in iliac limb deployment was 177 of 178(one intraoperative femorofemoral bypass for iliac graft occlusion). The mean stent graft landing distance to the hypogastric bifurcation was 8 ± 6.25 mm (standard error, 0.55 mm). As the result of a very precise deployment covering the entire length of common iliac artery, zone A and zone B were overlapping in 41.2% of cases. At a mean follow-up period of 32 months (range, 24-50 months), there were no distal type I endoleaks, no iliac graft migration, and 2 iliac limb occlusions (one in the ectatic CIA group; P = NS). There were 4 IRSIs (1 bypass, 3 surgical thrombectomy + stenting). The 4 -year freedom from IRSI was 97.1 (96.5% in the ectatic CIA group; P = NS). Distal iliac neck enlargement >2 mm occurred in 26% of cases (46 of 177), but no late type I distal endoleak was reported. Freedom from distal iliac neck enlargement was 84% and 73%, respectively, at 2 and 4 years, whereas freedom from type I distal endoleak was 100%. Conclusions Distal iliac neck enlargement may be associated to EVAR at midterm follow-up, but the dilatation exceeding the stent graft diameter is uncommon and not related to neck-related reintervention. Long-term surveillance, however, is mandatory, because IRSIs may be necessary especially in patients with uncovered portion of CIA.