While a tight seal and fixation of aortic stent-grafts to the vessel wall are vital for positive outcomes in treating abdominal aortic aneurysms (AAAs), optimal aortic stent-graft sizing for endovascular aneurysm repair (EVAR) remains debatable. We performed a holistic review of the data surrounding the sizing of endografts using instructions for use (IFU) guidelines, as well as experimental, computational, and clinical studies. Most clinical studies that have investigated the role of sizing and outcomes are limited by the strict selection criteria, or the inability to account for the multitude of confounders associated with sizing. Currently, oversizing of endografts between 10 and 20% remains safe and favored, but sizing outside the IFU guidelines frequently occurs. Oversizing up to 25% appears to be associated with decreased rates of proximal endoleak and aneurysm sac enlargement, while excessive oversizing (>30%) has been linked to graft infolding, collapse, and aortic dilatation. It is unclear, however, whether there is an association between oversizing associated with neck dilatation and graft migration. During sizing, surgeons should take an individual approach and consider several factors including device type, calcification and/or thrombus of apposition site, hemodynamics, and aortoiliac morphology.
Part of the book: Aortic Aneurysm