Influence of different self-expanding stent-graft types on remodeling of the aortic neck after endovascular aneurysm repair

Abstract

Purpose: To evaluate aortic neck changes, specifically aortic neck dilatation, over a 10-year period in patients undergoing endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm.

Methods: All patients who underwent elective EVAR at our institution from 1998 through 2007 were analyzed retrospectively. Among these, 103 patients (96 men; mean age 71 years, range 35-84) who received the 3 most frequently implanted self-expanding stent-grafts (35 Talent, 39 Excluder, and 29 Zenith) and had a minimum 3-month imaging follow-up at our department were selected for this study. All diameters were measured perpendicular to the centerline of flow on computed tomography; baseline data were derived from the first postoperative scan. Stent-graft migration was measured from the lowermost renal artery to the first strut of the stent-graft. Based on intra- and interobserver error measurements, a minimum change of 2 mm defined aortic neck dilatation.

Results: During a mean follow-up of 39.4 months (range 3-108.8), infrarenal aortic neck dilatation (>2 mm) was found in 10 patients (28.6%, 95% CI 14.6-46.3) in the Talent group, 4 (10.3%, 95% CI 2.9-24.2) in the Excluder group, and 9 (31.0%, 95% CI 15.3-50.8) in the Zenith group (p=0.299). In 7 (31%) of the 23 patients with neck dilatation, additional therapy was necessary. Suprarenal changes were found in 6 patients (17.1%, 95% CI 6.6-33.6), 8 patients (20.5%, 95% CI 9.3-36.5), and 5 patients (17.2%, 95% CI 5.8-35.8), respectively (p=0.218). Stent-graft migration >2 mm was seen in 2 (1.9%) of the 103 patients in follow-up. The overall endoleak rates were 37.1% for Talent, 30.8% for Excluder, and 37.9% for Zenith (p>0.05). Two patients were converted to open repair owing to Talent stent-graft migration and persistent type I leak (Zenith). The overall reintervention rate was 13.6% (13/103).

Conclusion: Only a small number of the patients treated with self-expanding stent-grafts show notable infrarenal aortic neck dilatation, which does not appear to be related to the stent-graft model. Almost all cases of aortic neck dilatation exceeded the percentage of oversizing; less than a third of patients with aortic neck dilatation required therapy.