Longitudinal aneurysm shrinkage following endovascular aortic aneurysm repair: a source of intermediate and late complications.

Purpose: To report the incidence of delayed complications following endovascular abdominal aortic aneurysm (AAA) repair and the relationship of these sequelae to morphological changes in the sac and endograft.

Methods: Twenty-six AAA patients treated with Vanguard endografts had completed > or = 1-year follow-up. Postoperative angiograms and spiral computed tomographic (CT) scans with 3-dimensional reconstruction were compared to the 1-year images to determine morphological changes in the aneurysm sac and the endograft. These changes were then related to complications occurring between 1 and 12 months postoperatively in the study group.

Results: Comparison of angiograms uncovered endograft buckling in 18 (69%) patients and acutely angled or kinked endografts in 10 (38%). Measurements from the CT scans found that undistorted endografts had a mean change in sac length of +6.6 mm. Mean sac length change in buckled endografts was -3.1 mm, while kinked endografts displayed a mean change of -6.2 mm (p < 0.002, Student's t-test). Five (19%) patients, all with distorted endografts, demonstrated late (1 to 12 months) complications (4 endoleaks and 1 graft limb thrombosis) owing to component separation, distal stent migration, and acute angulation. No movement in the proximal stent was observed. Elongation of the endograft (flow line measurement) was observed in one tube graft only.

Conclusions: In this study, longitudinal shrinkage of the sac following endovascular aortic aneurysm repair led to buckling or kinking of the endograft within 1 year in 69% of patients. This appears to be an important source of delayed complications.