BACKGROUND: The restenosis occurs up to 20%-30% following metal coronary stent implantation. Under the support of the 863 program, the feasibility to treat coronary artery stenosis using a novel drug-eluting stent (DES) has been investigated to reduce restenosis. OBJECTIVE: A drug-eluting stent (rapamycin as drug mode) was implanted into porcine models of coronary stenosis. The safety and efficacy of the drug-eluting stent were observed and compared with bare-metal stent. DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed in the Fu Wai Hospital for Cardiovascular Disease between November 2003 and April 2004. MATERIALS: A novel bioinspired phospholipid copolymer was synthesized by free radical polymerization of stearyl methacrylate, β-hydroxypropyl methacrylateand 3-(trimethoxysilyl) propylmethacrylate. METHODS: Twenty-one pigs were randomly divided into 3 groups: bare-mental stent, drug-eluting stent, and polymer-coated stent. The treated stents pre-loaded onto a delivery system through the use of crimping instrument were implanted into pig's coronary artery, with 2 stents per pig. MAIN OUTCOME MEASURES: Determination of luminal diameter, luminal area, mean intimal thickness on and between the stents, neointimal area, percentage of luminal area restenosis, and damage index using an image analysis instrument. RESULTS: At 28 days after implantation, there was significant difference in mean intimal thickness on and between the stents, as well as neointimal area, between the DES and bare-metal stent groups (P < 0.05). The neointimal area was reduced by 44.87% in the DES group compared with the bare-metal stent group. No significant difference in percentage of luminal area restenosis was found between the DES and bare-metal stent groups, but P value equaled to 0.053, which was close to 0.05. In addition, no restenosis was found in the DES group. CONCLUSION: Rapamycin DES can markedly resist intravascular intimal hyperplasia and restenosis following stenting.

A novel bioinspired phospholipid copolymer has been synthesized by the radical polymerization of poly2-Methacryloyloxyethylphosphorylcholine (MPC), stearyl methacrylate (SMA), hydroxypropyl methacrylate (HPMA) and trimethoxysilylpropyl methacrylate (TSMA). Contact angle results indicated that the coating surface rearranged to get a more hydrophilic surface at the polymer/water interface. The membrane mimic phosphorylcholine coating surface could resist the platelet adhesion and prolong plasma recalcification time significantly. Rapamycin was used as model drugs to prepare drug-eluting coating. The animal experiments showed that this novel drug-eluting stent could effectively prevent the phenomena of restenosis.
Angioplasty, Balloon, Coronary ; instrumentation ; Animals ; Coated Materials, Biocompatible ; Coronary Restenosis ; prevention & control ; Drug-Eluting Stents ; Female ; Humans ; Male ; Materials Testing ; Methacrylates ; chemistry ; Phosphorylcholine ; analogs & derivatives ; chemistry ; Pilot Projects ; Polymers ; chemistry ; Prosthesis Design ; Random Allocation ; Sirolimus ; chemistry ; Swine ; Swine, Miniature