The in vivo comparison of first versus second generation bioresorbable technologies early after implantation in the porcine coronary in stent restenosis model

Abstract

Abstract Background Second generation bioresorbable scaffold (BRS) technologies with thinner struts were developed to overcome thrombotic and restenotic events when compared to first generation Purpose Herein we compare vascular response and scaffold recoil of first generation BRS (Absorb, BVS, 150 micron) with second generation (Meres 100, MRS, 100 micron) in the porcine model of coronary in stent restenosis model Methods In total 11 BRS and 13 MRS similar scaffolds were implanted in 12 domestic swine, with 110% overstretch under Optical coherence tomography guidance. Animals were followed up for 2, 7 and 28 days (8 scaffolds for each period). At terminal follow up comprehensive evaluation with OCT was performed and tissues harvested for pathology Results Arterial injury expressed as overstretch was similar among groups. There were no differences at 2 and 7 days with regards to lumen area (LA), neointimal area (NA) stent areas (SA) and %AS. At 28 days SA and NA were lower in the MRS group when compared to BRS (SA: 5,1 vs. 8,8 mm2, p=0,01; NA: 1,94 vs. 3.36 mm2; p=0,01). Arterial healing was similar at 28 days between MRS and BRS as expressed by embedded and covered struts (100 vs 100%, p=1,0), however at 7 days there were more uncovered struts in the MRS (43% vs 12%, p=0,01). Conclusions Second generation MRS have proven improved vascular response in porcine coronary model with regard to lesser neointimal hyperplasia. Thinner struts however caused recoil when compared to thicker ones at early follow-up point. Further BRS material and design improvements are necessary to achieve metallic stent - like properties. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Center for Research and Development