| 摘要 |
A stent is made generally tubular and is initially formed in a collapsed configuration. A fabric cover is provided for the inner stent and is attached outside the stent at one or more desired locations. The fabric cover is much larger in diameter than the diameter of the collapsed stent, however, when the stent is expanded through activation of the balloon catheter therewithin, the stent expands to closely conform to the interior walls of the fabric cover. The attachment of the fabric cover and the stent may be accomplished in several ways. In one embodiment, the fabric cover may be attached outside the inner stent at one linear location parallel to the axis of elongation of the stent. In an alternative embodiment, the fabric cover may be attached concentrically about the inner stent and secured in that configuration by a series of sutures. In a further modification, the fabric cover may be attached around the inner stent non-concentrically through the use of suitable sutures. In a first alternative, one or more expandable clips are collapsed about the fabric cover to secure it about the inner stent. When the entire stent sandwich is expanded, these clips expand as well and comprise stents themselves. In a second alternative, securement of the fabric cover or intermediate stent layer about the inner stent is accomplished through the use of a wire spiraling externally about the outer surface of the fabric cover to secure the fabric cover or intermediate stent layer about the inner stent. When the stent sandwich is expanded, the configuration of this spiraling wire permits it to expand as well and lie against the inner walls of the blood vessel at the desired location. The stent has spaced ends, each of which may be coated or otherwise provided with a radio-opaque material. |
