Improved vascular response to a novel polymeric blend PLLA/PLGA coronary scaffold material: preclinical study

Thick struts and polymeric crystalline material are the potential mechanism of failure of the first generation bioresorbable scaffolds (BRS). We evaluated a novel fully amorphous bioresorbable scaffold (BRS) made of poly-L-lactide/poly-L-glycolide (PLLA/PLGA, Apollo, Biostent Consortium, Poland) in a porcine coronary restenosis model. Uncoated BRS (PLLA 120 μm, n = 7; PLLA 150 μm, n = 8; PLLA/PLGA 200 μm, n = 10) were implanted in 12 swine using OCT guidance and 110% overstretch. Follow-up included angiography, OCT, and histopathology at 30 and 90 days. At 30 days, OCT showed no significant differences in stenosis or neointimal hyperplasia between groups as represented by percent area stenosis (PLLA 120: 41% ± 17, PLLA 150: 52 ± 20%, PLLA/PLGA: 55 ± 6%; p = 0.07 ) and neointimal area (PLLA 120: 2.01 ± 0.8 mm², PLLA 150: 2.57 ± 1.1 mm², PLLA/PLGA: 2.02 ±0.8 mm²; p = 0.39). The average number and proportion of struts with no inflammation (score 0) was 7.2 fold higher in the PLLA/PLGA when compared to PLA 120 (p = 0,03). The endothelialization was nearly complete and comparable in all groups. At 90 days, PLLA/PLGA remained patent, covered, and free of restenosis, with positive remodeling and late lumen enlargement only in PLLA/PLGA group (lumen area 30 vs. 90 day: 1.86 vs. 3.40 mm², p = 0.02). The novel PLLA/PLGA BRS demonstrated improved healing, reduced inflammation and positive remodeling, supporting its potential for next-generation BRS.