Late problems at the proximal aortic neck: migration and dilation.

Migration is a late-term complication of endovascular aneurysm repair (EVAR) evidenced by downward slippage of the endograft. The etiology of migration may be inherent to problems with endograft fixation, although aortic neck dilation may also play a role. Devices with active fixation (ie, hooks and barbs) possess an additional mechanism of fixation and may better resist migration. Aortic neck dilation after EVAR is significant in a subset of patients and may be related to neck degeneration. Excessive oversizing of endografts may contribute to dilation and migration and is, therefore, not recommended. Migration should be treated when the overlap between the endograft and aortic neck is less than 10 mm or when associated with clinically significant events such as type I endoleak or aneurysm expansion. Failure to treat migration could lead to repressurization and subsequent rupture of the aneurysm.