Assessment of an asymmetrical coating stent with sirolimus released from ablumial matrix in porcine model

作者:Shen, Li; Wu, Yizhe; Zhang, Feng; Wu, Lingxiang; Dong, Chao; Gao, Yongxing; Sun, Aijun; Zou, Yunzeng; Qian, Juying; Sun, Jianguo; Zhong, Wei; Ge, Junbo*
来源:Clinical Research in Cardiology, 2012, 101(11): 917-927.
DOI:10.1007/s00392-012-0476-7

摘要

Delayed endothelialization contributes to stent thrombosis of current drug-eluting stents. The asymmetrical coating technique provides an anti-proliferative effect abluminally without affecting luminal endothelialization. Layer-by-layer self-assembled chitosan/heparin (C/H LBL) has been proved to promote re-endothelialization. A novel stent system, C/H LBL coated luminally and sirolimus released abluminally (C/H LBL-SES), was fabricated. @@@ Bare metal stents (BMS), traditionally circumferential sirolimus-eluting stents (SES), and C/H LBL-SES were implanted into porcine coronary arteries. At the 7, 14 and 28 days follow-up (FU), angiography, intravascular ultrasound (IVUS), vasomotor function induced by acetylcholine (Ach), scanning-electron microscopy and histopathology were performed. Remodeling index (RI) was based on IVUS and defined as cross-sectional area (CSA) of vessel at in-stent segment divided by CSA of reference vessel and expressed as a percentage with a normal range from 0.95 to 1.05. @@@ Thirty-eight mini pigs were enrolled and 74 stents (BMS = 23, C/H LBL = 28, SES = 23) were implanted in this study. At 28 days after implantation, the diameter stenosis of C/H LBL-SES by quantitative coronary angiography was 18.8 +/- A 2.5 %, the area stenosis by histomorphometry was 24.2 +/- A 2.9 %, which were comparable to that of SES and superior to BMS. At 14 days, re-endothelialization of C/H LBL-SES was almost completed, while only about 50 % of surface of SES was covered by endothelium. At 7, 14 and 28 days FU, although C/H LBL-SES suffered a greater vasoconstriction induced by Ach infusion than BMS (P < 0.05), it behaved better than SES (P < 0.01). No sign of stent malapposition was detected, while RI was within the normal range by IVUS. No acute or subacute thrombotic events occurred in all three groups. @@@ The asymmetrically designed C/H LBL-SES successfully inhibited neointima hyperplasia, while diminishing vasoconstriction after Ach-stress. Endothelialization of C/H LBL-SES was less affected compared with traditionally circumferentially coated SES.