Remodeling of proximal neck angulation after endovascular aneurysm repair

Abstract

Objective: This study investigated the remodeling of proximal neck (PN) angulations of abdominal aortic aneurysms (AAAs) after endovascular aneurysm repair (EVAR).

Methods: A 64-row multidetector computed tomography scan of AAAs treated with EVAR was reviewed, and the PN angulation was measured on a volume-rendered three-dimensional image. The computed tomography scan was examined preoperatively, after EVAR at 1 week, 1 month, 6 months, 1 year, 1.5 years, 2 years, and then yearly. The study enrolled 78 patients, comprising 54 Zenith devices (Cook Medical, Bloomington, Ind) and 24 Excluder devices (W. L. Gore and Associates, Flagstaff, Ariz).

Results: PN angulation was 50° ± 20° preoperatively, and after EVAR was 36° ± 14° at 1 week, 32° ± 14° at 1 year, and 28° ± 13° at 3 years. PN angulations ≤ 60° (n = 70, 77%) were 41° ± 13° preoperatively, 31° ± 12° 1 week after EVAR, 28° ± 12° at 1 year, and 26° ± 13° after 3 years. An angulation >60° (n = 18, 23%) was 78° ± 14° preoperatively, 51° ± 11° 1 week after EVAR, 44° ± 11° at 1 year, and 40° ± 12° after 3 years. The greater the preoperative PN angulation, the greater its reduction immediately after EVAR (r = .72, P < .001). The diameter shrinkage of AAAs with a PN angulation >60° was 3 ± 6 mm after 1 year; a significantly smaller shrinkage than with a PN angulation ≤ 60° (7 ± 7 mm, P < .05). AAAs with a PN angulation >60° had a larger angulation reduction and a smaller diameter shrinkage after the EVAR procedure. The PN angulation of the 54 AAAs treated by Zenith was 49° ± 22° preoperatively, 34° ± 14° 1 week after EVAR, and 25° ± 13° after 3 years. The corresponding angulation of the 24 AAAs treated by Excluder devices was 52° ± 17°, 41° ± 14°, and 38° ± 9°, respectively. The PN angulation reduction of Zenith and Excluder was similar 1 week after the EVAR procedure. Unlike Excluder, however, the PN angulation in Zenith continued to reduce for a long period at a slow pace. There were no significant correlations between PN angulation reduction and diameter change and between PN length and diameter change (P = .86 and .18, respectively).

Conclusions: Although the instructions for use of most commercially available stent grafts provide for a PN angulation of ≤ 60°, PN angulation was not a major issue in a midterm follow-up of AAAs with adequate PN length for patients in this series who received a Zenith or Excluder graft.