TY - JOUR
T1 - Image-Based Displacements Analysis and Computational Blood Dynamics after Endovascular Aneurysm Repair
AU - Domanin, Maurizio
AU - Piazzoli, Giulia
AU - Trimarchi, Santi
AU - Vergara, Christian
PY - 2020
Y1 - 2020
N2 - Background: To examine intraheartbeat displacements (IHD) and geometrical changes of endografts for abdominal aortic aneurysm repair over the course of years, defined as follow-up displacements (FUD), and to correlate them with computational fluid dynamics (CFD). Despite the widespread use of endovascular aneurysm repair (EVAR), we still know little about endograft behavior after deployment. Methods: Two cases, treated with either expanded polytetrafluoroethylene on a nitinol stent frame (PI) or with woven polyester fabric sutured to a stainless-steel Z stent skeleton (PII), were submitted to dynamic computed tomography angiography at 1, 12, and 60 months after implantation. After segmentation, IHD were computed as displacements of the reconstructed surface with respect to the diastolic instant. Similarly, FUD were studied using imaging techniques that align temporal successive segmentations. In addition, numerical simulations for blood dynamics were performed to compute viscous forces, specifically wall shear stress and time-averaged wall shear stress (TAWSS). Results: IHD analysis showed slight translations without deformation for the PI endograft with respect to the stiffer stainless-steel endograft behavior of PII. FUD showed in PI motion of the metallic struts mainly focused on the distal main body of the endograft and in the zone overlapping with iliac branches. In PII, we observed a huge FUD in the middle and inferior-anterior regions of the main body. CFD analysis revealed changes of velocity patterns associated with remodeling of the iliac zone for PI and of the main body region for PII, where flow impinges the lumen wall and progressively induces deformation of the endograft wires. Measurement of TAWSS demonstrated flow disturbances in the enlarged region correlated with displacement analysis. Conclusions: Image-based displacement analysis associated with CFD enabled very subtle evaluations of endograft behavior on different temporal scales. This kind of study could be helpful both for physicians, forecasting evolution during the life span of the endograft, and manufacturers, giving them useful information about endograft implant performance and design.
AB - Background: To examine intraheartbeat displacements (IHD) and geometrical changes of endografts for abdominal aortic aneurysm repair over the course of years, defined as follow-up displacements (FUD), and to correlate them with computational fluid dynamics (CFD). Despite the widespread use of endovascular aneurysm repair (EVAR), we still know little about endograft behavior after deployment. Methods: Two cases, treated with either expanded polytetrafluoroethylene on a nitinol stent frame (PI) or with woven polyester fabric sutured to a stainless-steel Z stent skeleton (PII), were submitted to dynamic computed tomography angiography at 1, 12, and 60 months after implantation. After segmentation, IHD were computed as displacements of the reconstructed surface with respect to the diastolic instant. Similarly, FUD were studied using imaging techniques that align temporal successive segmentations. In addition, numerical simulations for blood dynamics were performed to compute viscous forces, specifically wall shear stress and time-averaged wall shear stress (TAWSS). Results: IHD analysis showed slight translations without deformation for the PI endograft with respect to the stiffer stainless-steel endograft behavior of PII. FUD showed in PI motion of the metallic struts mainly focused on the distal main body of the endograft and in the zone overlapping with iliac branches. In PII, we observed a huge FUD in the middle and inferior-anterior regions of the main body. CFD analysis revealed changes of velocity patterns associated with remodeling of the iliac zone for PI and of the main body region for PII, where flow impinges the lumen wall and progressively induces deformation of the endograft wires. Measurement of TAWSS demonstrated flow disturbances in the enlarged region correlated with displacement analysis. Conclusions: Image-based displacement analysis associated with CFD enabled very subtle evaluations of endograft behavior on different temporal scales. This kind of study could be helpful both for physicians, forecasting evolution during the life span of the endograft, and manufacturers, giving them useful information about endograft implant performance and design.
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U2 - 10.1016/j.avsg.2020.07.014
DO - 10.1016/j.avsg.2020.07.014
M3 - Article
C2 - 32738387
AN - SCOPUS:85089824814
VL - 69
SP - 400
EP - 412
JO - Annals of Vascular Surgery
JF - Annals of Vascular Surgery
SN - 0890-5096
ER -