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In Vitro Analysis of Modular Aortic Stent-Graft Failure

Purpose: To investigate the theoretical forces involved in and the nature of fixation between the modular components of a variety of aortic stent-grafts. Methods: An in vitro study of 6 aortic stent-grafts was performed using a tensometer. The modular stent-graft components were distracted until the iliac limb was completely separated from the main body. Tests were repeated at least 6 times for each stent-graft. Results: The maximum pullout force was 36.0 N using the Fortron stent-graft, which resulted in stent-graft disintegration. The maximum median forces of the other stent-grafts were 23.7 N (19.9–31.2) for the Aorfix, 7.3 N (6.9–7.6) for the AneuRx, 7.0 N (6.8–7.1) for the Zenith BiFab, 5.4 N (5.0–6.5) for the Talent, and 2.4 N (2.2–2.4) for the Vanguard II Conclusion: The results of this in vitro study suggest that current forms of iliac limb fixation in modular aortic stent-grafts are adequate provided the components are deployed with sufficient overlap. However, for many of the stent-grafts tested, the safety margin was small.