Experimental Assessment of Proximal Stent-graft (InterVascularTM) Fixation in Human Cadaveric Infrarenal Aortas

Abstract

Objectivesthis paper investigates the radial deformation load of an aortic endoluminal prosthesis and determines the longitudinal load required to cause migration in a human cadaveric aorta of the endoprosthesis.Design and methodsthe endovascular prosthesis under investigation was a 24 mm diameter, nitinol, self-expanding aortoaortic device (InterVascular, Clearwater, Florida, U.S.A.). Initially, a motorised digital force gauge developed an incremental load which was applied to the ends of five stent-grafts, to a maximum of 10 mm (42%) compression. Secondly, using a simple bench model, each end of four stent-grafts were deployed into 10 cadaveric experimental aneurysm necks and a longitudinal load applied to effect distraction.Resultsincreasing load produced increasing percentage deformation of the stent-grafts. The mean longitudinal distraction load for an aneurysm neck of 20 mm was 409 g (200–480 g), for 15 mm was 277 g (130–410 g) and for 10 mm was 218 g (130–340 g). The aneurysm diameter and aortic calcification hadpvalues of 0.002 and 0.047, respectively, while thepvalue for aneurysm neck length was less than 0.00001.Conclusionsthese results suggest that there is a theoretical advantage of oversizing an aortic prosthesis and that sufficient anchorage is achieved in an aortic neck of 10 mm to prevent migration when fully deployed.