As part of an experimental study, an iliac limb stent graft was inserted in a pulsatile flow model similar to aortic in聽vivo conditions, and fixed-mounted at its proximal and distal ends to strain gauge load cells. Peak displacement forces at both ends and pulsatile graft movement were recorded at different graft angulations (0-90掳), perfusion pressures (145/80, 170/90, or 195/100聽mmHg), and stroke frequencies (60-100聽b.p.m.).
Flow-induced forces were of the same magnitude at the proximal and distal end of the stent graft (peak 1.8聽N). Both the forces and graft movement increased with angulation and perfusion pressure, but not with stroke rate. Graft movement reached a maximum of 0.29聽卤聽0.01聽mm per stroke despite fixed ends. There were strong correlations between proximal and distal displacement forces (r聽=聽0.97, p聽<聽.001), and between displacement forces and graft movement (r聽=聽0.98, p聽<聽.001).
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.