Explaining endograft shortening during endovascular repair of abdominal aortic aneurysms in severe aortoiliac tortuosity.

Objective: During endovascular aneurysm repair (EVAR), severely tortuous aortoiliac anatomy can alter the deployment and conformability of the endograft. The accuracy of treatment length measurements is commonly recognized to be affected by severe tortuosity. However, the exact mechanism of the postintervention length discrepancy is poorly understood. The objective of this study was to determine the mechanism of how severe aortoiliac tortuosity influences the endograft and native aorta during EVAR and its impact on the distal sealing zone.

Methods: A prospectively collected vascular surgery database was retrospectively reviewed at a university-affiliated medical center to identify the study patients. Patients who underwent EVAR with the main body device deployed on the side of the severely tortuous iliac artery were selected. Severe aortoiliac tortuosity was defined as having either aortoiliac or common iliac angulation <90 degrees.

Results: A total of 469 patients between 2008 and 2014 underwent EVAR using the Endurant endograft (Medtronic Cardiovascular, Santa Rosa, Calif). Severe aortoiliac tortuosity was observed in 36% of patients; 17 patients were found to have the main body placed on the side of severe tortuosity without an extension limb. There was a significant shortening of the main body endograft length from 169 mm before EVAR to 147 mm after EVAR (P < .001). The treatment length of the main body, measured from the lowest renal artery to hypogastric artery, also significantly shortened from 179 mm to 170 mm (P < .001). There was a decrease in tortuosity at the most angulated portion of the aneurysm after EVAR, in which angulation changed from 86 degrees to 114 degrees (P < .001). There was no significant change in treatment length (P = .859) and angulation (P = .195) on the nontortuous side of the aneurysm.

Conclusions: The study observed significant shortening of endografts and native aorta and iliac arteries in patients with severe aortoiliac tortuosity during EVAR. This shortening effect can have a negative impact on the distal sealing zone during EVAR. A longer main body or an extension limb should be considered when one is faced with severely tortuous aneurysms.