The burden of carotid-related strokes

After 3 decades of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms (AAA), the infrarenal neck is considered the most important determining factor for an uncomplicated and sustainable outcome. As the envelope has been pushed toward treating more challenging infrarenal necks with standard endografts, there are numerous publications regarding hostile aortic neck criteria.1–4 During preoperative planning and sizing, aortic neck length, diameter, suprarenal and infrarenal angulation, shape, and occurrence of calcium and thrombus are measured by most endovascular specialists, using dedicated software. Moreover, all endograft manufacturers have defined specific instructions for use (IFU) concerning infrarenal neck characteristics. Infrarenal neck length seems to be one of the most important criteria to consider, with a minimum of 10 or 15 mm, according to the IFU of most commercially available ndografts.3 According to most CoreLab definitions, the infrarenal neck ends when the aortic diameter increases >10% compared with baseline (ie, the diameter just below the lower margin of the lowest renal artery).5,6 Although the determination of the pre-EVAR neck characteristics gives the treating physicians a handle in the sizing and planning process, it does not always match with the actual circumferential seal of the endograft in the aortic neck after deployment. Oversizing the endograft’s main body often extends the seal compared with the predefined aortic neck length. However, especially in hostile necks, this does not always have the anticipated and desired effect.7 It seems reasonable to assume that the post-EVAR achieved circumferential apposition between the endograft and the aortic wall is a better indicator for outcome than the pre-EVAR determined aortic neck characteristics alone. The so-called sealing zone in the infrarenal aortic neck has received less attention in EVAR literature so far. A possible explanation for this might be that it is harder to define than the well-known aortic neck criteria. It also depends on the positioning of the endograft during the procedure. Moreover, the circumferential apposition between the endograft and the aortic wall has to be determined on the post- EVAR computed tomography (CT) scan, which is not a standard measurement so far.8 A Delphi method is often used to orchestrate expert opinions systematically when evidence is scarce or lacking, and research questions cannot simply be studied with experimental and epidemiological methods.9 In this study, the Delphi method is used to propose a consensus definition of the infrarenal sealing zone. Furthermore, it provides an algorithm to determine when and if adjunctive procedure(s) or reintervention should be considered in case of potential proximal sealing failure of the endograft.