.
`
`UHlted States Patent [19]
`Hillstead
`.
`
`USOO5135536A
`
`[11] Patent Number:
`[45] Date of Patent:
`
`5,135,536
`Aug. 4, 1992
`
`[54] ENDOVASCULAR STENT AND METHOD
`_
`_
`_
`_
`[75] Invento? Rlchard A- H?lstead, Mlarm, Fla.
`[73] Ass1gnee: glogdls Corporation, M1am1 Lakes,
`'
`-
`[21] Appl. No.: 650,699
`
`9
`
`4,830,003 5/1989 Wolff et al. ....................... .. 606/191
`4,856,516 8/1989 Hillstead
`.. 606/194
`5,019,090 5/1991 Pinchuk ............................ .. 606/194
`Prima'y Ex~aminer__ROna1d Frinks
`Attorney, Agent, or Firm-Watts, Hoffmann, Fisher &
`Heinke Co.
`
`[51] Int. Cl.5 ..................... .. A61M 29/00; A61F 2/06;
`[52] U S C]
`‘06/321222; O14
`' '
`' """"""""""""""""""" "
`;
`;
`623/12
`
`_
`_
`[58] Field of Search ...................... .. 23411081312035‘;
`’
`’
`
`A stem for reinforcing a vessel wan is disclosed. The
`stent is constructed from a single elongated wire. The
`wire is ?rst bent into a series of tight bends. The wire is
`.
`.
`.
`
`then rolled around a mandrel to create Junctions of wire
`which are psrmanen?y adhered The completed stem
`forms a cylindrical form which can be expanded from
`an initial diameter to a larger implanted diameter by
`application of a radially outward force from a balloon
`Catheter or the like‘
`
`[56]
`
`,
`
`,
`
`References Cited
`us’ PATENT DOCUMENTS
`4140126 2/1979 Ch dh
`
`ou ury ....................... ..
`
`606/194
`
`4,503,569 3/1985 Dotter . . . . . .
`
`. . . . . . . . . . .. 623/1
`
`4,733,665 3/1988 Palmaz .......................... .. 606/191 X
`
`24 Claims, 4 Drawing Sheets
`
`001
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`

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`US. Patent
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`Aug. 4, 1992
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`Sheet 1 of 4
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`5,135,536
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`002
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`

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`U.S. Patent
`US. Patent_ I
`
`Aug. 4, 1992
`
`5,135,536
`
`003
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`

`
`US. Patent ’
`
`Aug. 4, 1992
`
`Sheet 3 on
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`5,135,536
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`US. Patent
`
`Aug. 4, 1992
`
`Sheet 4 of 4
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`5,135,536
`
`005
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`

`
`1
`
`ENDOVASCULAR STENT AND METHOD
`
`TECHNICAL FIELD
`The present invention relates to an endoprosthesis
`device for implantation within a body vessel, typically a
`blood vessel.
`
`5,135,536
`2
`loon catheter to position the stent within a vessel. Once
`the stent is properly positioned the balloon is in?ated to
`press the stent against the inner wall linings of the ves
`sel. The balloon is then de?ated and withdrawn from
`the vessel, leaving the stent in place.
`
`BACKGROUND ART
`A type of endoprosthesis device, commonly referred
`to as a stent, is placed or implanted within a blood vessel
`for treating stenoses, strictures, or aneurysms in the
`blood vessel. These devices are implanted within the
`vascular system to reinforce collapsing, partially oc
`cluded, weakened, or abnormally dilated sections of the
`blood vessel. Stents also have been successfully im
`planted in the urinary tract or the bileducts to reinforce
`those body vessels.
`One common procedure for implanting the endopros
`thesis or stent is to ?rst open the region of the vessel
`with a balloon catheter and then place the stent in a
`position that bridges the weakened portion of the vessel.
`Prior art patents refer to the construction and design
`of both the stent as well as the apparatus for positioning
`the stent within the vessel. One representative patent is
`U.S. Pat. No. 4,140,126 to Chaudhury which issued
`Feb. 20, 1979. This patent discloses a technique for
`positioning an elongated cylindrical stent at a region of
`an aneurysm to avoid catastrophic failure of the blood
`vessel wall. The ‘126 patent discloses a cylinder that
`expands to its implanted con?guration after insertion
`with the aid of a catheter.
`A second prior art patent to Dotter, U.S. Pat. No.
`4,503,569 which issued Mar. 12, 1985 discloses a spring
`stent which expands to an implanted con?guration with
`a change in temperature. The spring stent is implanted
`in a coiled orientation and heated to cause the spring to
`expand.
`_
`U.S. Pat. No. 4,733,665 to Palmaz which issued Mar.
`29, 1988 discloses a number of stent con?gurations for
`implantation with the aid of a catheter. The catheter
`includes a mechanism for mounting and retaining the
`vascular prosthesis or stent, preferably on an inflatable
`portion of the catheter. The stent is implanted by posi
`tioning it within the blood vessel and monitoring its
`position on a viewing monitor. Once the stent is prop
`erly positioned, the catheter is expanded and the stent
`separated from the catheter body. The catheter can then
`be withdrawn from the subject, leaving the stent in
`place within the blood vessel.
`U.S. Pat. No. 4,856,516 to Hillstead entitled “En
`dovascular Stent Apparatus and Method” discloses a
`radially expandable stent for placement within a subject
`vessel. The stent is constructed from an elongated wire
`that is bent into a series of tight bends which are
`wrapped around a mandrel to form a series of loops.
`These loops are then interconnected by half hitch junc
`tions. The disclosure of the '516 patent to Hillstead is
`incorporated herein by reference.
`U.S. patent application Ser. No. 240,000 now U.S.
`Pat. No. 5,019,090, entitled “Radially Expandable En
`doprosthesis and the Like” discloses a generally cylin
`drical stent formed from a wire that is bent into a series
`of tight bends and then spirally wound about a cylindri
`cal mandrel to form the stent. If a radially outward
`force is applied to the stent the sharp bends in the wire
`tend to straighten and the stent diameter enlarges. One
`technique for implanting this stent uses a de?ated bal
`
`25
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`DISCLOSURE OF THE INVENTION
`Thepresent invention concerns a stent for placement
`within a subject. The-invention utilizes an elongated
`?exible ?lament bent into a series of tight bends extend
`ing along a series of transverse portions of the ?lament.
`The ?lament is then rolled around a mandrel to give the
`stent its cylindrical shape. The transverse portions meet
`along a series of junctions which are substantially
`aligned. These junctions are then permanently adhered
`to prevent unrolling of the completed stent. A backbone
`is formed by the adhering of these junctions in the stent
`thereby providing structure and strength.
`A feature of the invention allows for the omission of
`one or more stent segments thereby creating gaps to
`accommodate branching or crossing vessels within the
`subject vessel.
`The completed stent is of a sturdy, yet ?exible nature.
`It is capable of being easily placed within a subject
`vessel in a reduced diameter con?guration that ?ts
`within a guide catheter. When properly positioned, the
`stent can be expanded using a balloon catheter. The
`implanted stent provides support and reinforcement to
`the subject vessel as it heals.
`These and other objects of the invention will be bet
`ter understood from the following description of the
`invention which is described in conjunction with the
`accompanying drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a schematic depiction of a stent carried by
`a balloon catheter as the stent is routed to an implanta
`tion position;
`FIG. 2 is an elevation view of a stent embodying this
`invention;
`FIG. 3 is a plan view of a ?lament having a series of
`tight bends at regular intervals along its length;
`FIG. 4 is a plan view of the FIG. 3 ?lament indicating
`a manner in which the ?lament is bent during fabrica
`tion of the stent;
`FIG. 5 is a plan view of a planar form fabricated from
`the ?lament depicted in FIGS. 3 and 4;
`FIG. 6 is a plan view of the planar form of the ?la
`ment indicated in FIG. 5 with a mandrel for wrapping
`of the ?lament;
`FIG. 7 is a plan view of the ?lament indicated in FIG.
`6 wrapped around the mandrel; and,
`FIG. 8 is an elevation view of a stent embodying this
`invention with a section removed to create a gap to
`accommodate branching vessels.
`
`DETAILED DESCRIPTION
`Turning now to the drawings, FIG. 1 shows a gener
`ally cylindrical stent 10 mounted to a balloon catheter
`12 which is being routed through a patient’s cardiovas
`cular system to a weakened region 14 of a blood vessel
`15. The balloon catheter 12 is of a conventional design
`and includes a catheter portion that de?nes a passage
`way extending from the catheter’s proximal to distal
`end. The passageway allows ?uid to be routed to a
`balloon 16 near the catheter’s distal tip to in?ate the
`balloon. As the balloon in?ates it exerts a radially out- ,
`
`006
`
`

`
`5,135,536
`3
`4
`.
`.
`ment having a plurality of transverse portions each
`ward force against the stent 10 causing the stent to
`expand into contact with an inner wall of the blood
`de?ned by a series of at least three bends, said trans
`verse portions being rolled to create a cylindrical shape
`vessel 15.
`‘
`having closely spaced ?lament portions permanently
`To release the stent within the blood vessel 15, the
`adhered together to form junctions that prevent unroll
`balloon 16 is then de?ated causing the balloon and stent
`to separate. The stent 10 is then ?xed within the blood
`ing of said ?lament.
`.
`vessel 15 due to frictional engagement between the stent
`2. The stent of claim 1 wherein said junctions are
`and the inner wall lining of the blood vessel 15. The
`welded.
`3. The stent of claim 1 wherein said junctions are
`de?ated balloon 16 can then be freely withdrawn from i
`the stent. As this procedure is being accomplished, the
`soldered.
`attending physician can monitor progress of the stent
`4. The stent of claim 1 wherein said stent is radially
`implantation on a viewing monitor to determine the
`expandable from a ?rst outer diameter which ?ts within
`adequacy of the placement.
`said vessel to a second increased diameter which
`FIG. 2 depicts a stent 10 built from an elongated
`contacts an inner wall surface of said vessel to reinforce
`?lament 17, typically a wire, in accordance with this
`said inner wall.
`invention. As seen in FIGS. 3 and 4, series of bends 18
`5. The stent of claim 1 wherein an inner diameter of
`are formed at regular intervals. Each series of bends 18
`said stent is dimensioned to frictionally engage a nonin
`is spaced from an adjacent series by a straight segment
`?ated balloon catheter and be carried by said nonin
`19. Bending both ends v21 of each straight segment 19
`?ated catheter into a blood vessel.
`>
`forms a generally planar form de?ned by a series of
`- 6. The stent of claim 1 wherein said junctions are
`20
`regularly spaced along a length portion of said stent and
`transverse portions having a width C equal to the cir
`are permanently adhered and aligned along said length
`cumference of the stent 10 (See FIG. 5). The form is
`portion of said stent to form a relatively straight back
`then rolled around a mandrel 22 as shown in FIGS. 6
`and 7. After it is rolled, the stent 10 has a cylindrical
`bone to said stent.
`shape. Each end 21 of a straight segment 19 is closely
`7. The stent of claim 6 wherein gaps are left along
`said length portion of said stent to accommodate
`adjacent to a location 24 of a different straight segment
`19. The locations 24 are indicated in FIGS. 5 and 6.
`branches in said vessel so that said stent does not block
`off ?uid ?ow through said branches.
`Filament portions at the each end 21 and location 24
`are permanently adhered together to form junctions 26
`8. A stent for placement within a subject vessel com
`to prevent the unrolling of the stem 10 upon the re
`prising a support dimensioned to ?t within an interior of
`said subject vessel including an elongated ?exible ?la
`moval of the mandrel 22. The junctions 26 can be ad
`hered and formed through means of welding, soldering,
`ment de?ning a series of bends extending along a series
`tying or suturing. In the situation where the junctions
`of transverse portions that are rolled to create a cylin
`drical shape having closely spaced ?lament portions
`are tied or sutured, the material used for the tying or
`permanently adhered together by tying or suturing to
`suturing could be bio-degradable and in fact would be
`preferred. The junctions 26 are generally aligned to
`form junctions that prevent unrolling of said ?lament.
`form a backbone 27. End portions 28, 30 are hooked to
`9. A stent for placement within a subject vessel com
`a closely adjacent bend 18 at locations 32, 34 respec
`prising a support dimensioned to ?t within an interior of
`tively. The end portions could also be permanently
`said subject vessel including an elongated ?exible ?la
`adhered to their respective bends.
`ment de?ning a series of bends extending along a series
`A preferred stent 10 is constructed using tantalum
`of transverse portions that are rolled to create a cylin
`drical shape having closely spaced ?lament portions
`wire having a diameter of 5 thousandths of an inch.
`Before they are straightened by the balloon 16, the
`adhered together by tying or suturing with a biodegrad
`able material to form junctions that prevent unrolling of
`bends have typical widths w of 0048:0002 inch and
`lengths l of 0042:0003 inch (FIG. 5).
`said ?lament.
`A feature of the stent 10 constructed in accordance
`10. A stent for placement within a subject vessel
`with the present invention is its ability to expand as
`comprising a support dimensioned to ?t within an inte
`outward pressure is applied to its length by the balloon
`rior of said subject vessel including an elongated ?exi
`16. This ability stems from a combination of the factors
`ble ?lament de?ning a series of transverse portions,
`as previously discussed above. The main factor, how
`each transverse portion de?ning a series of at least three
`ever, is the series of sharp bends 18 applied to the fila
`bends, said transverse portions being rolled to create a
`cylindrical shape having closely spaced ?lament por
`ment 17 from which the stent 10 are constructed.
`One additional feature of the proposed construction is
`tions to form junctions that prevent unrolling of said
`the omission of one or more segments along length
`?lament, wherein:
`a) said junctions are regularly spaced along a length
`portions of the stent 10 which de?nes a gap G (illus
`trated in FIG. 8). This construction would accommo
`portion of said stent and are permanently adhered
`together and aligned along said length portion of
`date, for example, the use of the stent wherein side or
`branch vessels are encountered and would allow unim
`said stent to form a relatively straight backbone to
`peded ?uid ?ow to those side or branching vessels
`said stent;
`through judicious placement of the stent.
`b) said stent is radially expandable from a ?rst outer
`This stent embodiment have been described with a
`diameter which ?ts within said vessel to a second
`degree of particularity. It is the intent that the invention
`increased diameter which contacts an inner wall
`include all alterations from this embodiment falling
`surface of said vessel to reinforce said inner wall;
`within the spirit or scope of the appended claims.
`and,
`I claim:
`c) an inner diameter of said stent is dimensioned to
`1. A stent for placement within a subject vessel com
`frictionally engage a non-in?ated balloon catheter
`prising a support dimensioned to ?t within an interior of
`and be carried by said non-in?ated catheter into a
`said subject vessel including an elongated ?exible ?la~
`blood vessel.
`
`30
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`5,135,536
`6
`5
`f) removing said ?lament from said mandrel to de?ne
`11. The stent of claim 10 wherein said junctions are
`welded.
`a throughpassage for ?uid passage through said
`12. The stent of claim 10 wherein said junctions are
`stent in a region previously occupied by said man
`soldered.
`drel.
`13. The stent of claim 10 wherein gaps are left along
`17. The method of claim 16 wherein said junctions
`said length portion of said stent to accommodate
`are permanently adhered by welding.
`branches in said vessel so that said stent does not block
`18. The method of claim 16 wherein said junctions
`off ?uid ?ow through said branches.
`are permanently adhered by soldering.
`14. A stent for placement within a subject vessel ‘
`19. The method of claim 16 wherein subsequent to
`comprising a support dimensioned to ?t within an inte
`said removal of said stent from said mandrel, one or
`rior of said subject vessel including an elongated ?exi
`more transverse portions are removed from said stent to
`ble ?lament de?ning a series of bends extending along a
`create gaps to accommodate branching vessels and
`series of transverse portions that are rolled to create a
`allow unimpeded ?uid ?ow to said branching vessels
`cylindrical shape having closely spaced ?lament por
`after said stent is positioned within said vessel.
`tions to form junctions that prevent unrolling of said
`20. A method of fabricating a generally cylindrical
`?lament, wherein:
`stent, said method comprising:
`a) said junctions are regularly spaced along a length
`a) bending an elongated ?lament into a plurality of
`portion of said stent and are permanently adhered
`series of relatively tight bends;
`together by tying or suturing and are aligned along
`b) providing a cylindrical mandrel of a dimension
`said length portion of said stent to form a relatively
`smaller than an inner diameter of a vessel into
`straight backbone to said stent;
`which said stent is to be inserted;
`b) said stent is radially expandable from a ?rst outer
`c) rolling said ?lament around said mandrel to create
`diameter which ?ts within said vessel to a second
`junctions of ?lament thereby creating said cylindri
`increased diameter which contacts an inner wall
`cal shape;
`surface of said vessel to reinforce said inner wall;
`d) permanently adhering said junctions of ?lament;
`and,
`e) removing said ?lament from said mandrel to de?ne
`c) an inner diameter of said stent is dimensioned to
`a throughpassage for ?uid passage through said
`frictionally engage a non-in?ated balloon catheter
`stent in a region previously occupied by said man
`and be carried by said non-in?ated catheter into a
`drel; and,
`blood vessel. -
`i) removing one or more sections of ?lament from
`15. A stent for placement within a subject vessel
`said stent to create gaps to accommodate branch
`comprising a support dimensioned to ?t within an inte
`ing vessels and allow unimpeded ?uid ?ow to said
`rior of said subject vessel including an elongated ?exi
`branching vessels after said stent is positioned
`ble ?lament de?ning a series of bends extending along a
`within said vessel.
`series of transverse portions that are rolled to create a
`cylindrical shape having closely spaced ?lament por
`21. A method of fabricating a generally cylindrical
`tions to form junctions that prevent unrolling of said
`stent, said method comprising:
`?lament, wherein:
`a) bending an elongated ?lament into a plurality of
`a) said junctions are regularly spaced along a length
`series of relatively tight bends;
`portion of said stent and are adhered together by
`b) providing a cylindrical mandrel of a dimension
`tying or suturing with a biodegradable material and
`smaller than an inner diameter of a vessel into
`are aligned along said length portion of said stent to
`which said stent is to be inserted;
`form a relatively straight backbone to said stent;
`c) rolling said ?lament around said mandrel to create
`b) said stent is radially expandable from a ?rst outer
`junctions of ?laments thereby creating said cylin
`diameter which ?ts within said vessel to a second
`drical shape;
`increased diameter which contacts an inner wall
`d) permanently adhering said junctions of ?lament by
`surface of said vessel to reinforce said inner wall;
`tying or suturing;
`and,
`e) removing said ?lament from said mandrel to de?ne
`c) an inner diameter of said stent is dimensioned to
`a throughpassage for ?uid passage through said
`frictionally engage a non-in?ated balloon catheter
`stent in a region previously occupied by said man
`and be carried by said non-in?ated catheter into a
`drel.
`blood vessel.
`22. A method of fabricating a generally cylindrical
`16. A method of fabricating a generally cylindrical
`stent, said method comprising:
`stent, said method comprising:
`a) bending an elongated ?lament into a plurality of
`a) bending an elongated ?lament into a plurality of
`55
`series of relatively tight bends;
`series of relatively tight bends;
`b) providing a cylindrical mandrel of a dimension
`b) bending said ?lament into a plurality of transverse
`smaller than an inner diameter of a vessel into
`portions, each transverse portion having at least
`which said stent is to be inserted;
`three of the relatively tight bends;
`c) rolling said filament around said mandrel to create
`c) providing a cylindrical mandrel of a dimension
`junctions of ?lament thereby creating said cylindri
`smaller than an inner diameter of a vessel into
`cal shape;
`which said stent is to be inserted;
`(1) adhering said junctions of ?lament by tying or
`d) rolling said ?lament around said mandrel such that
`suturing with a biodegradable material;
`ends of said transverse portions meet locations of
`e) removing said ?lament from said mandrel to de?ne
`adjacent ?lament portions thereby creating said
`cylindrical shape;
`a throughpassage for ?uid passage through said
`stent in a region previously occupied by said man
`e) permanently adhering said ends and locations to
`drel.
`create junctions of ?lament; and
`
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`' 7
`23. A stent for reinforcing a vessel within a subject
`comprising a cylindrical support dimensioned to ?t
`within an interior of said vessel including:
`a) an elongated ?lament bent to de?ne segments of
`relatively tightly spaced bends which form a plu
`rality of loops spaced along an axial dimension of
`the stent connected by a plurality of generally
`straight wire segments; and,
`b) means for connecting together different straight
`wire segments;
`
`5,135,536
`8
`wherein said stent is radially expandable from a ?rst
`outer diameter which ?ts within said vessel to a second
`increased diameter which contacts an inner wall surface -
`of said vessel to reinforce said inner wall.
`24. A stent for reinforcing a vessel comprising a wire
`having alternating bent and straight portions wherein
`the bent portions form cicumferential loops about a
`stent throughpassage to bring alternate straight line
`portions into contact at aligned locations along a length
`of the stent, and means for connecting at least some of
`said straight portion locations together.
`
`5
`
`‘ * ‘ i i
`
`20
`
`25
`
`35
`
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`
`65
`
`009