Effect of abdominal aortic endoprostheses on arterial pulse wave velocity in an in vitro abdominal aortic flow model

Objective: Aortic pulse-wave-velocity (aPWV) is a measure for arterial stiffness, which is associated with increased cardiovascular risk. Recent evidence suggests aPWV increases after endograft-placement for aortic aneurysms. The aim of this study was to investigate the influence of different aortic endoprostheses on aPWV and structural stiffness in vitro. Approach: Three different abdominal aortic endoprostheses (AFX, Endurant II, and Nellix) were implanted in identical silicone aneurysm models. One model was left untreated, and another model contained an aortic tube graft (Gelweave). The models were placed in an in vitro flow set-up that mimics physiological flow. aPWV was measured as the transit time of the pressure wave over the flow trajectory of the suprarenal to iliac segment. Structural stiffness corrected for lumen diameter was calculated for each model. Results: aPWV was significantly lower for the control compared to the AFX, Endurant, Nellix and tube graft models (13.00 +/- 1.20,13.40 +/- 1.17,18.18 +/- 1.20,16.19 +/- 1.25 and 15.41 +/- 0.87 m s(-1), respectively (P <0.05)). Structural stiffness of the AFX model was significant lower compared to the control model (4718 N m(-1 )versus 5115 N m(-1) (P <0.001), respectively), whereas all other models showed higher structural stiffness. Significance: Endograft placement resulted in a higher aPWV compared to a non-treated aortic flow model. All models showed increased structural stiffness over the flow trajectory compared to the control model, except for the AFX endoprosthesis. Future studies in patients treated with an endograft are needed to evaluate the current results in vivo.