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

Abstract

AIM: 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. METHODS: 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). RESULTS: 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 (? (s) = 0.50; p < 0.001), and serial analyses revealed an evolving association over time. CONCLUSION: 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.