Proximal Fixation of Thoracic Stent-Grafts as a Function of Oversizing and Increasing Aortic Arch Angulation in Human Cadaveric Aortas

Purpose:To assess the fixation of 4 commercially available thoracic stent-grafts as a function of oversizing and increasing aortic arch angulation.Methods:A benchtop pulsatile flow model was devised to test stent-graft anchorage in a 2-cm-long proximal landing zone at varying landing zone angles (70° to 140°) and stent-graft oversizing (5% to 37%). The experiments were performed using 15 human thoracic cadaveric aortas and 4 stent-grafts with different proximal anchoring mechanisms: TAG, Zenith TX, Valiant, and Relay. The lack of device-wall apposition was measured as a function of landing zone angulation and oversizing during static and dynamic (60 pulses/min, 300/150 mmHg) tests; stent-graft collapse was also investigated.Results:The Valiant stent-graft remained apposed to the aortic wall at each increment of neck angulation and degree of oversizing. Lack of apposition of the proximal anchorage segment (Relay: bare spring; TAG: scalloped flares) was observed with the Relay above 80° landing zone angulat...