Sideways displacement of the endograft within the aneurysm sac is associated with late adverse events after endovascular aneurysm repair.

OBJECTIVE: Previous studies have shown the importance of proximal and distal endograft fixation. There is little information on the middle, unsupported section of endograft within the aneurysm sac. We quantified sideways movement of the endograft within the aneurysm sac and correlated it to late adverse events.
METHODS: Patients who underwent endovascular abdominal aortic aneurysm (AAA) repair with a suprarenal or infrarenal endograft between January 1997 and December 2007 were analyzed for sideways endograft movement. Patients were included if they had a digital preoperative computed tomography angiogram (CTA), a postoperative CTA within 3 months after the index procedure, and at least one follow-up CTA thereafter with a minimal time interval of 6 months. The endograft position within the aneurysm sac was quantitated on cross-sectional images using a fixed vertebral body reference point. Patients with change in endograft position ≥5 mm were placed in the sideways displacement (SD) group and compared with patients with no displacement (ND; <5 mm change in position). The relationship between sideways endograft movement and endovascular aneurysm repair (EVAR)-related complications were noted for AAA rupture, AAA-related death, conversion, secondary procedures, AAA growth (≥5 mm), proximal migration (≥10 mm), and new onset of type I or III endoleaks.
RESULTS: The study included 144 patients (mean age, 76 ± 7.6 years). Mean follow-up time was 43 ± 27 months. Fifty patients (35%) had sideways endograft movement ≥5 mm during follow-up. Baseline AAA diameter was larger (SD 60 ± 9 mm vs ND 57 ± 9 mm; P < .05) and proximal and iliac endograft fixation lengths were shorter (SD 18 ± 8 mm vs ND 24 ± 11 mm; P < .05 and SD 35 ± 14 vs ND 42 ± 16 mm; P < .05) in patients with sideways endograft displacement. There was no significant difference between the groups in AAA rupture and AAA-related death (one fatal AAA rupture, ND group). SD patients had a higher surgical conversion rate (10% vs 0%; P = .002), more secondary procedures (44% vs 6%; P < .001), more AAA sac enlargement (42% vs 10%; P < .001), more endograft migration (66% vs 5%; P < .001), and more type I or III endoleaks (36% vs 3%; P < .001).
CONCLUSIONS: Positional stability of the endograft within the aneurysm sac is critical for the long-term success of EVAR. Sideways movement of the endograft within the aneurysm sac is associated with an increased risk of late adverse events.