Expandable stent and method for delivery of same

Abstract

An expandable stent having a proximal end and a distal end in communication with one another, and a tubular wall disposed between the proximal end and the distal end. The tubular wall has a longitudinal axis and a porous surface defined by a plurality of intersecting members comprising a series of longitudinal struts disposed substantially parallel to the longitudinal axis of the stent. Each longitudinal strut in the series comprises flexure members for substantially complementary extension and compression of a diametrically opposed pair of the longitudinal struts upon flexure of the stent. The flexure members may comprise first and second curved sections which are of a different size. At least one of the curved sections may comprise an arc of greater than about 180°.

Description

[0001]This is a continuation application of application Ser. No. 11 / 831,693, filed Jul. 31, 2007, which is a continuation application of application Ser. No. 11 / 419,895, filed May 23, 2006 (abandoned), which is a continuation application of application Ser. No. 10 / 849,990 (now U.S. Pat. No. 7,094,255, issued Aug. 22, 2006), filed May 21, 2004, which is a continuation of application Ser. No. 09 / 672,768 (now U.S. Pat. No. 6,758,860, issued Jul. 6, 2004), which is a continuation of application Ser. No. 09 / 142,509, filed Feb. 18, 1999 (now U.S. Pat. No. 6,183,506, issued Feb. 6, 2001), which is a 371 of PCT / CA97 / 00152), filed Mar. 5, 1997 (designating the U.S.; and published in English as WO 97 / 32544 on Sep. 12, 1997), which claims benefit of (i) CA 2,171,047, filed Mar. 5, 1996, (ii) CA 2,175,722, filed May 3, 1996, (iii) CA 2,185,740, filed Sep. 17, 1996, and (iv) CA 2,192,520, filed Dec. 10, 1996, the contents of which are incorporated herein by reference.TECHNICAL FIELD[0002]The pre...

AI Technical Summary

Benefits of technology

[0024]Thus, in this aspect of the present invention, we have now discovered that the use of flexure means in the series of longitudinal struts leads to a very desirable balance of lateral flexibility of the unexpanded stent and radial rigidity of the expanded stent. Practically, the flexure means confers lateral flexibility to the unexpanded stent by allowing diametrically opposed pairs of the longitudinal struts to undergo substantially complementary extension and compression. If one considers a stent in a flexed state, a first longitudinal strut disposed at the tangent of the bend (i.e. in two dimensions) will expand in response to the bending moment. In contrast, a second longitudinal strut disposed diametrically opposite (this can mean above, below or in the same radial plane as) the first longitudinal strut will compress in response to the bending bend moment. Generally, the degree of extension and compression will be substantially complementary. In other words, in most cases, the first longitudinal strut will expand and lengthen a first distance and the second longitudinal strut will compress and shorten a second distance. Preferably, the first distance is greater than the second distance and most preferably, the sum of the first distance and the second distance is substantially equal to the sum of the original lengths of the first longitudinal strut and the second longitudinal strut.

[0046]In yet another embodiment of the invention, the stent may be secured (e.g. by suturing) to an existing endoluminal prosthesis such as Gortex™ material or to biological material such as basilic vein. In this regard, securing of the stent to the existing endoluminal prosthesis or biological material may be facilitated by designing the stent such that an end of the stent comprises an annular row of the above-mentioned polygons is having a convex-shaped wall with a flat apex.

Problems solved by technology

The self-expanding stents were found by some investigators to be deficient since, when deployed, they could place undue, permanent stress on the walls of the body passageway.

Further, upon expansion, the stent would shorten in length in an unpredictable fashion thereby reducing the reliability of the stent.

This led to the development of various stents which were controllably expandable at the target body passageway so that only sufficient force to maintain the patency of the body passageway was applied in expanding the stent.

Further, implantation of the stent disclosed in the '997 application can be difficult in certain situations where the unexpanded stent must travel through a significantly curved pathway to the target body passageway.

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