Fabrication of micropored elastomeric film-covered stents and acute-phase performances.
To prevent thrombus formation in the acute phase and restenosis in the subacute to chronic phase after stenting of atherosclerotic arteries, we developed a covered stent with a micropored elastomeric film, the blood-contacting surface of which was coated with a photocured gelatin layer immobilized with heparin. Segmented polyurethane (SPU) film (30 microm in wall thickness) as a cover material was multiply micropored by excimer laser-directed microprocessing (pore diameter, 30 microm; interpore distance, 125 microm). An aqueous mixed solution of benzophenone-derivatized gelatin and heparin was coated on the micropored SPU film. Upon ultraviolet light irradiation, a thin layer of a gelatin gel immobilized with heparin was formed and simultaneously fixed on the SPU film. The fully covered stents were assembled by wrapping a balloon-expandable stent with gelatin/heparin gel-layered SPU film and subsequently suturing and then gluing. To assess the validity of this covered stent in vivo, "half-covered" stents, in which half at the distal side was covered with the gel-layered SPU film, was implanted in rabbit common carotid arteries (about 3 mm in diameter). After 3 months of implantation, all the half-covered stents (n = 7) were patent. Regardless of the covered or noncovered region of the stents, the entire luminal surface of the stents was fully endothelialized and a thin neointimal tissue was formed. The potential advantages of a covered stent as designed above are discussed.
Nakayama
Yasuhide
Y
Department of Bioengineering, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
Nishi
Shogo
S
Ueda-Ishibashi
Hatsue
H
Matsuda
Takehisa
T
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D020724:Elastomers / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011817:Rabbits; D015607:Stents
D001672:Biocompatible Materials; D020724:Elastomers