Device-specific aneurysm sac morphology after endovascular aneurysm repair: evaluation of contemporary graft materials.

Objective: This study analyzed device-specific aneurysm sac morphology after endovascular aneurysm repair (EVAR) with low-permeability devices.

Methods: Between September 2004 and May 2006, 122 patients were treated with EVAR. Three different devices were implanted: 47 Zenith (Cook, Indianapolis, Ind), 46 AneuRx (Medtronic, Santa Rosa, Calif) with Resilient Dacron Graft Material, and 29 Excluder (W. L. Gore & Associates, Flagstaff, Ariz) with low-porosity polytetrafluoroethylene (PTFE). Patients were followed up at 1, 6, and 12 months and then biannually with computed tomography (CT) angiography. Standard axial two-dimensional CT measurements were obtained and compared with preoperative imaging. The preoperative scan served as a baseline, and the minor axis diameter, measured at the largest axial cut of the abdominal aortic aneurysm, was compared with the same measurement at follow-up.

Results: Patient age, sex, and preoperative aneurysm morphology were similar among groups. Patients receiving the Zenith endograft had a significantly larger neck diameter; however, there was no difference in the neck length between groups. The rate of type II endoleaks was similar for the Zenith (17%), AneuRx (17%), and Excluder (14%). At 1, 6, 12, and 18 months, all three grafts were associated with sac shrinkage. The resulting decreases in mean aneurysm size at 18 months and corresponding shrinkage were Zenith, 11%, 6.4 +/- 1.8 mm; AneuRx, 18.9%, 12.7 +/- 2.7 mm; and the Excluder, 5.5%, 3.3 +/- 0.9 (P < .05). The sac size in the 19 patients with a type II endoleak decreased 8.06% compared with a 15.43% decrease in sac size in patients without endoleak at 6 months. No significant sac expansion > or =5 mm has been observed among any of the groups to date.

Conclusions: Sac regression with all devices appears to have been favorably influenced by the new generation of graft materials and is improved compared with published reports of older generation graft materials for the AneuRx and Excluder. However, there is a trend toward greater sac regression with devices using Dacron vs PTFE. The relationship of aneurysm morphology and long-term effects on aortic stent grafts is yet to be determined.