OBJECTIVETo investigate late stent malapposition or vessel remodeling post chitosan/heparin layer-by-layer self assembly coating stent (LBL) implantation in porcine.

METHODSA total of 32 stents [bare metal stent (BMS, n = 9), sirolimus-eluting stent (SES, n = 11) and LBL (n = 12)] were implanted into coronary arteries of 16 porcine. Intravascular ultrasound (IVUS) was performed immediately after stenting and at 1 month after stenting to measure vessel area (VA), stent area (SA) and lumen area (LA). Neointima area (NA) was measured at 1 month post stenting by IVUS to detect signs of stent malapposition and to determine remodeling index (RI). Histopathology was performed at 1 month post stenting to observe vessel wall structure and stent malapposition status.

RESULTSNo sign of stent malapposition was detected, VA and SA/LA were similar among groups immediately after stent implantation. At 1 month follow-up, none of three groups showed stent malapposition. VA, SA, NA and LA were (7.30 ± 0.77), (6.83 ± 0.76), (1.40 ± 0.96) and (5.43 ± 0.88) mm(2) in LBL group, (7.13 ± 0.69), (6.63 ± 0.71), (0.28 ± 0.35) and (6.34 ± 0.89) mm(2) in SES group, (7.48 ± 0.70), (7.00 ± 0.52), (2.69 ± 1.58) and (4.31 ± 1.28) mm(2) in BMS group. VA and SA were similar among groups (all P > 0.05). LA in LBL group was smaller than SES group (P < 0.01) and significantly larger than in BMS group (P < 0.05).NA in LBL group was larger than SES group (P < 0.01) and significantly smaller than in BMS group (P < 0.05).RI in LBL, SES and BMS groups was 0.95 ± 0.07, 1.02 ± 0.04 and 0.98 ± 0.04 (P > 0.05).

CONCLUSIONSThere is no late stent malapposition or abnormal remodeling post LBL, SES and BMS implantation up to 1 month in this porcine model. LA in LBL group is smaller than SES group and larger than BMS group at 1 month after implantation in this porcine model.