Stent-Graft Deployment Increases Aortic Stiffness in an Ex Vivo Porcine Model

Abstract

Aortic stiffness is an independent predictor of cardiovascular mortality. In this study, the effect of thoracic endovascular aortic repair (TEVAR) on aortic stiffness is investigated by measuring aortic pulse wave velocity (PWV) in an exvivo porcine model. Fifteen fresh porcine thoracic aortas were connected to a benchtop pulsatile system. Intraluminal pressures were recorded in the ascending aorta and at the celiac trunk using a needle connected to a pressure sensor. The distance between the needles was divided by the time difference between the base of the pressure peaks to calculate aortic PWV at baseline and after stent-graft deployment and distal stent-graft extension. Mean aortic PWV was 5.0m/s at baseline. PWV increased by 4% after proximal stent-graft deployment (P=0.09) and by 18% after stent-graft extension (P<0.001). Pulse pressure in the nonstented ascending aorta increased by 11.0±1.2mm Hg after proximal stent-graft deployment (P<0.001) and by 17.3±1.5mm Hg after stent-graft extension (P<0.001). The increases in PWV and pulse pressure showed a positive linear correlation with the percentage of stent-graft coverage (P<0.001 and P<0.001). In this experimental setup, aortic stiffness increased after stent-graft deployment, dependent on the percentage of the aorta that was covered by stent graft. These results show that TEVAR leads to significant changes in aortic hemodynamics, which merits evaluation in the clinical setting.