Endothelial Cell Distribution After Flow Exposure With Two Stent Struts Placed in Different Angles

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Vascular Biology

Background:

• Stent implantation is crucial for treating intravascular diseases like stenosis.
• Stent struts can cause endothelial cell (EC) damage and disrupt blood flow, leading to restenosis and thrombosis.
• Understanding EC behavior around stent struts is vital for improving device safety and efficacy.

Purpose of the Study:

• To investigate the impact of flow alterations caused by gaps between stent struts on EC distribution.
• To analyze EC migration and endothelialization on strut surfaces under varying flow conditions.
• To correlate computational fluid dynamics (CFD) simulations of wall shear stress (WSS) with observed EC patterns.

Main Methods:

• Placing two stent struts with defined orientations and positions on an EC layer within a parallel flow chamber.
• Exposing the setup to wall shear stress (WSS) for 24 hours to observe EC distribution, particularly in the gap area.
• Conducting CFD simulations to calculate WSS distribution and correlate it with EC concentration on fluorescence images.

Main Results:

• High EC concentration areas corresponded to high WSS regions created by the gap between struts.
• Endothelialization rates (EC density) were higher on the downstream sides of struts compared to upstream sides, especially in the gap's recirculation zone.
• EC density varied along struts placed at tilted angles, indicating that strut orientation influences EC distribution.

Conclusions:

• The presence of a gap between stent struts significantly influences EC distribution and migration patterns.
• CFD simulations of WSS can predict EC distribution around stent struts.
• Understanding these flow-mediated EC responses is key to optimizing stent design and placement to minimize adverse vascular reactions.