Displacement Forces in Iliac Landing Zones and Stent Graft Interconnections in Endovascular Aortic Repair: An Experimental Study

Abstract

Pulsatile flow through a tubular untapered stent graft causes forces of similar magnitude at both ends and induces pulsatile graft movements in its unsupported mid-section. Peak forces are close to those previously reported to be required to extract a stent graft. The forces and movements increase with increasing graft angulation and perfusion pressure. Improved anchoring of the distal end of stent grafts may be considered.

Displacement Forces in Stent Grafts: Influence of Diameter Variation and Curvature Asymmetry

“…Previously published results for non-tapered stent grafts 12 have been confirmed in the present study. Peak forces of approximately 1.7 N were registered at both ends of the grafts, and forces were of the same magnitude at both ends of the graft for all curvatures and pressures.…”

“…11 Furthermore, it has been shown previously that flow induced stent graft displacement forces are significant, dependent on graft angulation and perfusion pressure, and of similar magnitude at both ends of a nontapered iliac stent graft. 12 Forces of a magnitude of 1.8 N were found, which is close to the force previously shown to be able to displace a stent graft. 13e17 There is a high correlation between the degree of pulsatile movement of the stent graft and the magnitude of displacement forces.…”

“…It has been shown previously that flow induced extraction forces in a non-tapered iliac limb stent graft are significant, of the same magnitude at the proximal and distal ends, and dependent on angulation and fluid pressure. 12 Furthermore, there was a significant correlation between the degree of sideways movement of the stent graft and the magnitude of extraction forces. The extraction forces reached 1.8 N, which is close to what is needed to pull out a non-barbed stent graft (2e4 N).…”

“…The experimental set up has previously been described in detail. 12 Briefly, pulsatile flow was achieved with a computer triggered pump, which was connected to a closed circuit (Fig. 1).…”

“…13e17 There is a high correlation between the degree of pulsatile movement of the stent graft and the magnitude of displacement forces. 12 The aim of the present study was to investigate how flow induced displacement forces and stent graft movement depend on the distal diameter of iliac limb stent grafts and asymmetric graft curvatures.…”