Study of Folding in Endovascular Grafts due to Oversizing

Endovascular grafts (EVG) are stent grafts implanted percutaneously to repair aortic aneurysms. The primary source of fixation of the EVG is the friction from radial forces generated by graft over-sizing. Although a 10–20% over-sizing is common, it may range from 0 to 45% [1]. A clinical study on patient outcomes noted high migration rates when oversizing was greater than 30%. A recent in vitro study of barbed EVGs by our group found that greater than 30% oversizing results in decreased fixation strength quantified by the force needed to pullout the graft from the aorta [2]. In that study, based on anecdotal visual observation, we hypothesized that grafts with excessive oversizing may be folding, resulting in poor fixation strength. In this study, we ranked the level of folding noted in EVGs with varying oversizing in order to test that hypothesis.