# Preclinical serial shear stress analysis of a novel strut-free fibrillated bioresorbable polymeric endoluminal graft

## TL;DR

A new type of dissolvable blood vessel implant was tested in animals to see how blood flow patterns affect healing and artery remodeling over time.

## Contribution

A novel strut-free, fibrillated bioresorbable scaffold was evaluated for its impact on endothelial shear stress and vascular remodeling in preclinical models.

## Key findings

- The scaffold produced a more uniform endothelial shear stress profile compared to lattice-based stents.
- Early endothelial shear stress correlated with subsequent lumen gain in the scaffolded arteries.
- Endothelial shear stress showed a modest upward trend during the 3-month follow-up period.

## Abstract

To characterise near-wall haemodynamics immediately after implantation of a next-generation, strut-free biorestorative endoluminal graft, evaluate changes over 3 months during resorption, and assess whether early flow patterns may influence subsequent remodelling in two preclinical models.

Three rabbits and six mini-pigs underwent bilateral implantation of a resorbable fibrillated scaffold (RFS) in peripheral arteries. Intravascular optical coherence tomography (OCT) combined with angiography enabled generation of 29 case-specific three-dimensional reconstructions during a 3-month study period. Pulsatile, non-Newtonian computational fluid dynamics (CFD) quantified the endothelial shear stress (ESS).

OCT demonstrated a continuous endoluminal surface consistent with the strut-free RFS design and revealed a distinct optical transition at the device boundary. Haemodynamic mapping showed low-ESS regions at scaffold edges and broadly unidirectional near-wall flow within the scaffolded segment. Quantitatively, ESS showed a modest, non-significant upward trend during follow-up before stabilising (rabbits: +0.37 Pa, p = 0.085; mini-pigs: +0.37 Pa, p = 0.091). Higher early ESS correlated with subsequent lumen gain (ρs = 0.50; p < 0.001), and serial analyses revealed an evolving association over time.

RFS implantation instated a largely homogeneous ESS profile that evolved with 3-month remodelling, consistent with a dynamic flow-healing interplay that warrants longer-term evaluation through full bioresorption.

Resorbable fibrillated scaffold (RFS) shear stress assessment in a preclinical study. Bilateral RFS implants in rabbit external iliac and mini-pig profunda femoris arteries were evaluated over 3 months. Endothelial shear stress (ESS) was quantified using three-dimensional geometries reconstructed by OCT-angiographic fusion. The strut-free, continuous-wall scaffold generated a more uniform ESS profile than typical of lattice-based stents, and post-implantation ESS correlated with subsequent lumen remodelling.Schematic overview of a resorbable fibrillated vascular scaffold implanted within an arterial vessel. A magnified inset shows the micro-fibrillar scaffold structure interacting with the vessel wall. Diagrams indicate the experimental timeline and implantation sites in rabbit and mini-pig models. A colour-mapped profile illustrates a near-uniform endothelial shear stress distribution along the scaffolded vessel segment. An accompanying graph depicts vessel remodelling, showing the relationship between endothelial shear stress and corresponding changes in lumen area over time.

Resorbable fibrillated scaffold (RFS) shear stress assessment in a preclinical study. Bilateral RFS implants in rabbit external iliac and mini-pig profunda femoris arteries were evaluated over 3 months. Endothelial shear stress (ESS) was quantified using three-dimensional geometries reconstructed by OCT-angiographic fusion. The strut-free, continuous-wall scaffold generated a more uniform ESS profile than typical of lattice-based stents, and post-implantation ESS correlated with subsequent lumen remodelling.