Anatomic and hemodynamic investigation of an occluded common carotid chimney stent graft for hybrid thoracic aortic aneurysm repair

Abstract

We examined the possible reasons for common carotid artery chimney stent graft occlusion through computational fluid dynamics analyses of follow-up imaging of a patient-specific aortic configuration reconstructed from computed tomography aortography. Anatomic and hemodynamic parameters were extracted for the bilateral common carotid and subclavian arteries before and after endograft placement. Results suggested that postoperative reduction in lumen diameter within the chimney stent graft combined with an increased flow rate led to complex hemodynamics with high wall shear stress, probably resulting in high-shear thrombogenesis and chimney stent graft occlusion 2.6 years after the primary repair. Early postoperative duplex ultrasound imaging might help identify at-risk conditions.

Use of Stainless-Steel, Balloon-Expandable Chimney Grafts Is Durable Though Caution Is Required When Lining Angulated Renal Arteries

“…In the parallel setting of these devices, adherence of the target vessel to the surrounding structures together with the respiratory movements could move the stented vessel downward, forcing the stent into an angulated segment and leading to kinking. Also, as proven recently by Tricarico et al, 12 lumen diameter reduction due to vessel stenting increases the flow rate within the vessel, producing hemodynamic changes and high wall shear stress that can lead to occlusion of the stentgraft. Also, the stiffness of the guidewire, the length of the CG, and involvement of its distal edge in the angulated segment influence the risk of CG kinking and subsequent occlusion.…”