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

Abstract

<h4>Aim</h4>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.<h4>Methods</h4>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).<h4>Results</h4>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, <i>p</i> = 0.085; mini-pigs: +0.37 Pa, <i>p</i> = 0.091). Higher early ESS correlated with subsequent lumen gain (<i>ρ</i> _s = 0.50; <i>p</i> < 0.001), and serial analyses revealed an evolving association over time.<h4>Conclusion</h4>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.