Aortoiliac remodeling and 5-year outcome of an ultralow-profile endograft.

BACKGROUND

Remodeling of the aortoiliac anatomy is a challenge to the long-term performance of stent grafts for endovascular aneurysm repair. Changes in vessel diameter and length can result in loss of seal at attachment sites, limb disunion, or kinking, with the development of high-pressure endoleaks, migration, or limb occlusion. The aim of this study was to assess the durability and conformability of the ultralow-profile INCRAFT AAA endograft (Cordis Corporation, Milpitas, Calif) during 5-year follow-up.

METHODS

From 2010 to 2011, there were 60 patients (median age, 74 years; range, 60-94 years) with intact abdominal aortic aneurysms who were enrolled in the INNOVATION trial to evaluate the safety, effectiveness, and durability of the INCRAFT AAA device. Clinical and technical success was assessed with protocol-specified, monitored follow-up clinic visits and core laboratory-assessed computed tomography (CT) at 1 month, 6 months, and 12 months after implantation and annually through 5 years thereafter. Diameter and angulation changes at the proximal aortic neck and diameter changes at the iliac attachment zones were measured in addition to the standard CT assessments.

RESULTS

Significant aortoiliac remodeling was observed throughout long-term follow-up after endovascular aneurysm repair. Proximal aortic neck diameter 15 mm below the lowest main renal artery increased from 23.5 ± 2.5 mm at 1 month to 27.3 ± 2.8 mm at 5 years (P = .002). Neck dilation >5 mm was observed in 8 of 38 patients with 5-year CT studies (21%). The aortic neck straightened, with angulation decreasing from 34 ± 14 degrees preoperatively to 31 ± 11 degrees at 1 month (P < .001) and to 20 ± 12 degrees at 5 years (P = .018). Straightening of the neck was most prominent in patients who presented with a high degree of preoperative angulation (r = 0.61; P < .001). Between 1 month and 5 years, iliac attachment zone diameter increased from 13.5 ± 1.9 mm to 15.0 ± 2.4 mm on the right (P = .002) and from 13.9 ± 2.3 mm to 16.8 ± 2.7 mm on the left (P < .001). During 5 years, 9 of 72 (13%) iliac arteries enlarged >5 mm. There was a significant relationship between main body oversizing and aortic neck enlargement (r = 0.42; P = .009). No similar association was observed between iliac limb oversizing and iliac dilation over time (r = 0.10 and P = .549, right side; r = 0.14 and P = .400, left side). There were no aneurysm-related deaths in the series. There were two type IA endoleaks, both of which were present on the 1-month CT scan and associated with challenging aortic neck anatomy. No patient experienced endograft migration or rupture through 5 years. Type IB endoleaks occurred in two patients, both accompanied by iliac artery dilation and loss of seal. Stent fracture occurred in two struts of the bare transrenal stent of one patient, without loss of fixation or seal. One patient experienced graft limb occlusion and was observed without intervention. There were three patients (5%) with aneurysm sac enlargement (>5 mm) through 5 years, each of whom had type II endoleak.

CONCLUSIONS

Significant aortoiliac remodeling occurs after endograft implantation, including proximal aortic neck dilation, straightening of the neck, and iliac artery enlargement. The ultralow-profile INCRAFT device adapted well to these changes, with acceptably low 5-year rates of device-related endoleaks, endograft migration, and limb occlusion.