Deformation Mechanics of Self-expanding Venous Stents: Modelling and Experiments

TL;DR

This study compares various venous stent designs through experiments and modeling, highlighting their deformation properties and suitability for different clinical scenarios, with a semi-analytical method aiding design optimization.

Contribution

It introduces a combined experimental and analytical approach to evaluate and optimize venous stent deformation characteristics.

Findings

Stainless steel stents have superior collapse resistance.

Braided design exerts larger radial pressure on small vessels.

Z design minimizes foreshortening for accurate deployment.

Abstract

Deformation properties of venous stents based on braided design, chevron design, Z design, and diamond design are compared using in vitro experiments coupled with analytical and finite element modelling. Their suitability for deployment in different clinical contexts is assessed based on their deformation characteristics. Self-expanding stainless steel stents possess superior collapse resistance compared to Nitinol stents. Consequently, they may be more reliable to treat diseases like May-Thurner syndrome in which resistance against a concentrated (pinching) force applied on the stent is needed to prevent collapse. Braided design applies a larger radial pressure particularly for vessels of diameter smaller than 75% of its nominal diameter, making it suitable for a long lesion with high recoil. Z design has the least foreshortening, which aids in accurate deployment. Nitinol stents are more compliant than their stainless steel counterparts, which indicates their suitability in veins. The semi-analytical method presented can aid in rapid assessment of topology governed deformation characteristics of stents and their design optimization