Supra-aortic Remodeling After EVAR During One-year Follow-up: Comparison Between Three Different Fixation Types of Endografts

Abstract

Introduction -The remodeling of the supra-renal aorta after endovascular aortic aneurysm repair (EVAR) in relation to different endograft design has not been fully investigated. The aim of this study was to assess the anatomic changes in supra-renal aorta post-EVAR with the use of different types of endografts during the first year. Methods - In total 100 patients undergoing EVAR with 3 types of endografts having different proximal fixation system were retrospectively analyzed. Fifty consecutive patients were treated with Ovation (supra-renal fixation and infra-renal sealing with polymer ring; Endologix, Irvin, CA, USA), 25 with Endurant (supra-renal fixation; Medtronic Cardiovascular, Santa Rosa, Calif, USA), and 25 with Excluder (infra-renal fixation; W.L. Gore & Associates, Flagstaff, AZ, USA). Baseline calcification (0 to 2) and thrombus (0 to 2) at the neck, co-morbidities and anatomical variables were recorded. Anatomic variables were AAA maximum diameter, supra-renal neck angulation, and diameters of the supra-renal aorta at 5mm, 15mm, 25mm, and 35mm above the most cephalad renal artery. Computed tomography angiography (CTA) was obtained pre-operatively at 1 and 12 months post-EVAR. Results - The mean AAA diameter was 56.5mm, 57mm and 55mm in Ovation, Endurant and Excluder group, respectively. Co-morbidities were not different across the 3 groups. Presence and amount of neck calcification (p=0.139) and thrombus (p=0.116) was similar among groups. Maximum aortic diameter showed significant reduction from pre-operative to 12-month post-operative CT scan for all 3 groups. (Ovation group: 56.5mm to 53mm; p<0.001, Endurant group: 57mm to 51mm; p<0.001, Excluder group: 55mm to 50mm; p<0.001). Regarding supra-renal aortic diameter changes, only the Ovation group showed a significant increase at all levels (mean increase of 1mm), except at 15mm which remained stable. Changes in supra-renal angulation were also significant only in the Ovation group (100, 80, 70; p<0.001) and Excluder group (220, 200, 180; p=0.05). Among the three different endografts, maximum diameter decrease, was not different (p=0.99), supra-renal aortic diameter increase, was significantly higher only in Ovation group at levels of 5mm (p=0.02) and 25mm (p=0.01) while there were no differences observed at the level of 15mm (p=0.12) and 35mm (p=0.25) and supra-renal angulation reduction was not different (p=0.7). No migration or endoleak type I was observed in any patient. Endoleak type II was observed in 18/50, 6/25 and 7/25 in Ovation, Endurant and Excluder group, respectively, (p=0.532). Conclusion - The type of endograft fixation system appears to have different impact on supra-aortic anatomy in terms of supra-renal aortic diameter and anglulation, but without any clinical effect in the first post-EVAR year. Longer follow up is needed to clarify future remodeling and clinical impact of these observations and whether any type of endograft requires more intense follow up.