Eccentric stent graft compression: An indicator of insecure proximal fixation of aortic stent graft

Purpose: The purpose of this study was to determine whether radiographicall y demonstrated proximal stent graft contour fan be used as a marker for sec urity of proximal neck fixation after endovascular aneurysm repair. Methods: Stent graft structure was examined in 100 consecutive patients wit h abdominal aortic aneurysms who were treated with the stent graft. Stent g raft integrity, stent contour, angulation, compression, and position were a ssessed by use of plain abdominal radiography, and the results were correla ted with contrast computed tomography (CT) scanning clinical findings, and outcomes. Repented imaging was carried out during follow-up of 3 to 38 (mea n, 12) months. Results: Stent graft repair was successful in all 100 patients. No stent fr actures were identified. Concentric compression of the proximal portion of the stent graft was visible in 69% of patients and reflected deliberate ove rsizing of the stent graft at the time of implantation. In 5% of patients, a short eccentric compression deformity of the proximal stent was observed. This finding was associated with an increased risk of stent graft migratio n (P < .01) and with an increased risk for development of a late proximal ( type I) endoleak (P < .01). Compared with CT scanning, abdominal radiograph y was less useful for assessment of short distances of migration (sensitivi ty 67%; specificity 79%). However, they provided better definition of the s tent graft iu relation to bony landmarks and better visualization of aortic calcification than CT with three-dimensional reconstruction. Conclusion: Plain abdominal radiographs are important in the postoperative evaluation of patients with aortic stent grafts. They allow for more precis e evaluation of the structural elements of the stent graft than CT scanning and may disclose inadequate proximal fixation by demonstration of an eccen tric compression deformity. They are less useful for assessment of migratio n.