Functional hemodynamic and wall shear stress assessment of a novel endoluminal fibrillated polymeric scaffold up to full resorption within 12 months in a preclinical in-vivo setting

Background Novel resorbable fibrillated scaffolds (RFS) fabricated by electrospinning poly-L-lactide-based polymers have a porous matrix conducive to host cell infiltration, inducing endoluminal tissue reconstruction. This biomaterial opens an avenue of research in recreating a novel and favourable endoluminal lining in diseased vessel. Previous preclinical work has shown that implants in the aorta of rodents generate layers of endoluminal elastin. In humans, one of the most impervious arteries to atherosclerosis is the intra-thoracic artery; therefore, an attempt to induce similar structures with an implantable device was made. Methods Twelve RFSs in the iliac arteries of nine rabbits and twelve RFSs in profunda arteries in six mini pigs were implanted percutaneously and followed up to 12 months, during which optical coherence tomography (OCT) was performed for luminal assessment dimensions and fractional flow reserve derived from angiography (µFR) and OCT (OFR). Results The overall pooled analysis at different follow-up timepoints (N=52 vessels) showed an average minimum lumen diameter (OCT-MLD) of 1.95±0.54mm and 2.48±0.66mm in the rabbits and the mini-pigs, respectively. On average, QCA-diameter stenosis (DS) was 39±17% [OCT-Area stenosis (AS): 50±23%] in the rabbits and 31±16% [AS: 51±20%] in the mini-pig. The mean µFR was 0.88±0.15 and 0.90±0.12 in the rabbits and mini pigs, respectively. The mean OFR was 0.96±0.03 (OFR ranging from 0.66 to 1.00) and 0.95±0.07 (0.42 to 1.00) in the rabbits and the mini pigs, respectively. Pooled analysis shows a significant curvilinear relationship between AS and OFR (R = - 0.707, p< 0.01). At follow-up timepoint, in only one vessel, the OFR was ≤0.90. This suggests that almost all vessels had no ischemic flow limitation. Conclusion The current study shows the durability and favourable hemodynamics of this bioresorbable fibrillated scaffold at short and medium-term follow-up, supporting the potential utility of RFSs for peripheral human artery revascularisation. Long-term follow-ups are mandatory to confirm the durability of these results. Histopathology of this preclinical model should confirm the endoluminal elastin as previously documented in rodents (rats) and wall shear stress derived from angiography and OCT pullback will be presented at the time of the congress.