| 摘要 |
A method for maintaining the integrity of a vessel via a stent is described. Using this method, both the risk of permanent vessel collapse and the risk of dislodging the stent from the implant site is minimised if the stent is temporarily deformed due to external forces. A crush-resistant stent having either shape memory or superelastic properties is used. The stent is mounted onto a delivery catheter, comprising: providing a substantially cylindrically-shaped stent having crush-resistant superelastic properties and including a plurality of cylindrical elements disposed generally coaxially and connected together by interconnecting members between the cylindrical elements; temporarily affixing the cylindrically-shaped stent about the delivery catheter and placing the stent under stress and compressing it to a delivery diameter. FIG. 3 is an elevational view, partially in section, depicting a stent mounted on a delivery catheter and expanded within a damaged vessel, pressing the damaged vessel lining against the vessel wall and providing a retractable delivery sheath over the stent to maintain the stress on the stent. The stent (10) includes a plurality of radially expandable cylindrical elements (24) disposed coaxially and interconnected by members (26) between adjacent cylindrical elements (24). The stent is formed from a superelastic material such as NiTi and undergoes an isothermal reaction when stressed. The stent is first compressed to a delivery diameter, thereby creating stress in the NiTi alloy so that the NiTi is in a martensitic state having relatively low tensile strength. In the martensitic phase, the stent is mounted onto a catheter by known methods such as adhesives, or other restraining means. Alternatively, the stent can be mounted within the delivery sheath (16) so that the stent, which is biased radially outwardly, is pushing radially outwardly against the sheath. In its delivery diameter, the overall diameter of the stent and catheter are less than the inside diameter of the artery (28) or the vessel in which they are inserted. After the stent is inserted into the artery or other vessel, the stress upon the stent may be removed by withdrawing the delivery sheath in a proximal direction, whereupon the stent immediately expands and returns to its original undeformed shape by the transformation back to the more stable austenite phase.
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