| 摘要 |
The present invention comprises a stent forming a plurality of meandering elements comprising a blend formed from a polymer. The polymer comprises poly-L-lactide, poly-D-lactide or mixtures thereof and a copolymer moiety comprising poly-L-lactide or poly-D-lactide linked with &egr;-caprolactone or trimethylcarbonate. The poly-L-lactide or poly-D-lactide sequence in the copolymer moiety is random with respect to the distribution of &egr;-caprolactone or trimethylcarbonate and the copolymer moiety molecular weight ranges from about 1.2 IV to about 4.8 IV. The meandering elements may be stretched to a modulus ranging from about 250000 PSI to about 550,000 PSI, one segment of the meandering element has a decreased cross-sectional area and may have a wide-angle X-ray scattering (WAXS) 2&thetas; values of ranging from about 1 to about 35. In various embodiment, two, three or n segments of the meandering element have a decreased cross-sectional area and may also have a wide-angle X-ray scattering (WAXS) 2&thetas; values of ranging from about 1 to about 35 after stretching. In another embodiment, all segments of the meandering element have a decreased cross-sectional area and may also have a wide-angle X-ray scattering (WAXS) 2&thetas; values of ranging from about 1 to about 35 after stretching. The meandering element may comprise a helical winding, a circumferential winding or stent ringlet. The properties of the bioabsorbable polymers allow for both crimping and expansion of the stent. The crystal properties of the bioabsorbable polymers may change during crimping and/or expansion allowing for improved mechanical properties such as tensile strength and slower degradation kinetics.
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