The impact of triple anti-platelet therapy for endothelialization and inflammatory response at overlapping bioabsorbable polymer coated drug-eluting stents in a porcine coronary model

Abstract

Background: This study was conducted to evaluate the endothelialization and the inflammatory responses depending on the administration duration of triple anti-platelet therapy at overlapping bioabsorbable polymer coated biolimus-eluting stents (BESs) in a porcine coronary model.

Methods: We successfully deployed 36 overlapping BESs for the left anterior descending coronary and left circumflex artery or right coronary artery in 18 non-injured pigs. Total pigs were divided into 3 groups (12 overlapping stents of 6 pigs in each group) as follows: group I received aspirin 100mg and clopidogrel 75 mg daily for 8 weeks, group II received aspirin 100mg and clopidogrel 75 mg daily for 8 weeks and cilostazol 200mg daily for initial 4 weeks, and group III received aspirin 100mg, clopidogrel 75 mg, and cilostazol 200mg daily for 8 weeks. Follow-up coronary angiograms and histomorphometric and histopahtologic analyses at overlapping and non-overlapping segments were performed respectively.

Results: Inflammation score was similar between overlapping and non-overlapping segments in all pigs (1.2 ± 0.33 vs. 1.1 ± 0.17, p=0.117). The neointima area (NA) and percent area stenosis (%AS) at overlapping segments were not significantly different among the 3 groups. However, at non-overlapping segments, NA and %AS in group III were significantly smaller than those in group I (2.3 ± 0.50mm(2) vs. 1.8 ± 0.43 mm(2), p=0.037; 48.9 ± 12.85% vs. 37.7 ± 9.08%, p=0.031).

Conclusions: Our study shows that BES appears to be reliable on the inflammatory response at overlapping segments as well as non-overlapping segments. Long-term administration of cilostazol is more effective in reducing neointimal formation at non-overlapping segments of BESs in a porcine coronary model.

Keywords: Cilostazol; Drug-eluting stents; Inflammation; Restenosis.