Hemodynamics in Cerebral Aneurysms and Parent Arteries With Incompletely Expanded Flow Diverter Stents

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Fluid Dynamics

Background:

• Braided stents, including flow diverter stents (FDS), are used for cerebral aneurysms.
• Incomplete stent expansion (IncompSE) during deployment is a potential complication.
• IncompSE can lead to poor stent apposition, increasing risks of complications and incomplete aneurysm occlusion.

Purpose of the Study:

• To investigate hemodynamic parameters associated with IncompSE using computational fluid dynamics (CFD).
• To compare hemodynamic changes between complete stent expansion (CompSE) and IncompSE.

Main Methods:

• Generated three basic geometries representing an internal carotid artery siphon aneurysm.
• Conducted CFD analysis for 12 patterns: pre-deployment, CompSE, and IncompSE (distal and proximal).
• Calculated the change rate (CR) of hemodynamic parameters influencing occlusion or complications.

Main Results:

• CompSE led to a significant decrease in aneurysm volume flow (VF) and maximum wall shear stress (WSS).
• IncompSE resulted in higher VF, inflow jets, vortices, and increased WSS at the aneurysmal neck and parent artery.
• Static pressure and energy loss increased within the aneurysm in IncompSE cases, unlike CompSE.

Conclusions:

• Incomplete stent expansion (IncompSE) of FDS can induce unfavorable hemodynamic changes.
• These changes include increased blood flow and elevated pressure within the aneurysm, potentially hindering treatment effectiveness.
• CFD analysis is valuable for understanding the hemodynamic impact of IncompSE in cerebral aneurysm treatment.