[Influence of fixation mechanism on changes of the supra- and infrarenal segment of the aorta after endovascular treatment of infrarenal aortic aneurysm].

INTRODUCTION: Dilatation of the infrarenal aortic segment determines the long-term outcome after endovascular repair of abdominal aortic aneurysms. This segment is crucial for sealing and preventing stent-graft migration. The purpose of this study was to evaluate influence of fixation mechanism on changes of supra- and infrarenal aortic diameters over a 10-year period. METHODS: We reviewed all our endovascular procedures for abdominal aortic aneurysms and follow-up CT scans between 1998 and 2008. Only patients with the three most frequently implanted self-expandable stent-graft types and a minimal follow-up of three months were included in this study. Further inclusion criteria were elective repair and follow-up at our department to consistent data formats. A total of 103 patients, 35 with suprarenal fixation without hooks (Medtronic Talent®, Medtronic World Medical, Sunrise, FL, USA), 29 with suprarenal fixation with hooks (Cook Zenith®, Cook Inc. Bloomington, IN, USA) and 39 with infrarenal fixation with anchors (Gore Excluder®, W. L. Gore & Associates, Flagstaff, Ariz, USA) met the inclusion criteria. All measurements were performed in duplicate by two different investigators to determine intra- and interobserver errors. Based on this error a minimal change of 2 mm of infrarenal aortic neck diameter was determined as aortic neck dilatation. RESULTS: During a mean follow-up time of 39.4 (3-108.8) months, infrarenal aortic neck dilatation was found in 28.57 % in the Medtronic group, 10.26 % in the Gore group and 31.03 in the Cook group. Suprarenal changes were 17.14 %, 20.51 % and 17.24 %, respectively. Reduction of the maximal diameter could be achieved in 74.3 % (Medtronic), 79.5 % (Gore), and 75.8 % (Cook). Seven of 23 patients with a notable dilatation of the infrarenal neck required reintervention. All of them were stent-grafts with suprarenal fixation. No statistical significance was found between the 3 groups regarding changes of suprarenal or infrarenal diameters or migration rates. CONCLUSION: Although no statistical significance was found among the groups, infrarenal fixation showed the lowest rate of infrarenal dilatation.