LAUSR

BACKGROUND: In silico studies have provided robust evidence that stent design affects local hemodynamic forces, which appear as a major determinant of clinical outcomes following stent implantation. However, implications of different stent/scaffold configurations on local hemodynamic forces have not yet been investigated in vivo in a comparative fashion. METHOD AND RESULTS: Eight healthy mini pigs were implanted with six Absorb everolimus-eluting Bioresorbable Vascular Scaffolds (Absorb BVS) and five Mirage sirolimus-eluting Bioresorbable Microfiber Scaffolds (Mirage BRMS). Optical coherence tomography (OCT) was performed and strut protrusion was assessed post scaffold implantation. Following the reconstruction of coronary anatomy blood flow simulation was performed and endothelial shear stress (ESS) was estimated on top of the struts and at luminal surface between the struts in each scaffold. The thicker struts in Absorb (152±140µm) resulted in an increased protruded distance compared to Mirage (117±123 µm) (p=0.003). This had an effect in the local hemodynamic microenvironment. ESS at top-of-the struts were higher in Absorb (1.69±1.20 Pa) than in Mirage (1.53±0.91 Pa), (p<0.001) but lower at inter-strut zones (0.60±0.51Pa vs 0.63±0.50 Pa; p<0.01) compared to Mirage. Both scaffold types revealed comparable percentages of vessel luminal surface exposed to recirculation. CONCLUSION: Absorb demonstrated higher shear stress on top of the struts compared to Mirage. However, in the inter-struts zones shear stress was higher in Mirage than in Absorb. Further research is required to examine potential value of in vivo computational modeling in optimizing scaffold configuration and clinical outcomes.