Maybe neck dilation matters after all?

Durability and long-term success of EVAR depends upon achieving and maintaining appropriate proximal seal and fixation within the infrarenal aortic neck. Aortic neck dilation (AND) has been well documented in the existing literature and has been suggested as a potential source of critical EVAR failure through endoleaks and stent migration. Although other reports have suggested that AND occurs generally without clinical consequence, here, Oliveira et al. report that AND does in fact have an important relationship with EVAR failure in longer follow-up in their large single-center experience¹.

Importantly, these authors demonstrated that AND was more common than previous smaller series³, and occurred in the vast majority of cases. which may be explained by better long-term follow-up. Similar to prior studies, while AND was found to occur most rapidly during the first year, it remained present and ongoing throughout the lifetime of surveillance, in the majority of patients. Despite that finding, prior reports are relatively reassuring that AND occurs without clinical significance^2,3.

Risk factors for AND identified in this study mirror findings from previous publications³, and also found an association with graft oversizing. The role of oversizing in development of AND is difficult to define with confidence in this report, but the association should certainly give operators pause during stengraft selection. These results are limited by the wide variation in oversizing within the sample (13% −28% oversizing) and potential bias introduced through measurement techniques, device selection and patient substrate related to the quality and diameter of the infrarenal neck. Despite these limitations, this relationship remains concerning, and should certainly be further explored.

Unique to this study was the identified relationship of AND to both development of Type 1a endoleaks and stentgraft migration. These relationships have intuitively always made sense, and perhaps had not previously been demonstrated simply due to smaller sample sizes and limited follow-up^3,4.

Although there are conflicting reports in the literature, AND has been well demonstrated to be a frequent occurrence after EVAR and, at least in this report, increases the rate of important adverse events that can cause late treatment failure. Whether AND is caused by the stentgraft design and/or oversizing and truly leads to failure, or is simply related to poor patient selection and use of infrarenal EVAR in patients destined to fail therapy, is still not completely clear.

In any case, these findings support the critical role that rigorous long-term follow-up plays after EVAR, which has certainly been emphasized in the existing literature⁵. This work also highlights the importance of appropriate pre-operative decision-making with relation to device longevity and patient life-expectancy.