United States Patent [191
`Pinchuk
`
`llllllllllillllllllllillllllwlllllllllllIllllllllllilllllllllIlllllllllll
`
`S005226913A
`Patent Number:
`[11]
`[45] Date of Patent:
`
`5,226,913
`Jul. 13, 1993
`
`[54] METHOD OF MAKING A RADIALLY
`EXPANDABLE PROSTHESIS
`
`FOREIGN PATENT DOCUMENTS
`
`_
`
`
`
`
`[75] Inventor: Leonard Pinchuk, Miami, Fla. 73 Ass- : 13 ~ - -
`
`
`I
`]
`lgnee Com Corpomwn’ Mlaml’ Fla
`[21] Appl. N0.: 844,481
`,
`[22] F11¢d=
`
`Mir-2i 1992
`
`0282175 9/1988 European Pat. Off. .
`0312852 4/1989 European Pat. on. .
`408245A1 1/1991 European Pat. Off. .
`1205743 9/1970 United Kingdom .
`2135585 9/1984 United Kingdom.
`
`[62]
`
`Related US. Application Data
`Division of Ser. No. 548,101, Jul. 5, 1990, Pat. No.
`5,092,877, which is adivision of $31‘. No. 240,000, Sep.
`1, 1988, Pat. No. 5,019,090.
`
`OTHER PUBLICATIONS
`131511“ et a1’ "§XPam_1ab1e Imralummal Graft‘ A Pm‘
`llmmary Study, Radiology, 156= 73-77, 1985'
`Palmaz et al, “Expandable lntrahepatic Portacaval
`Shunt Stents: Early Experience in the Dog,” American
`
`Journal ofRadl-ology’ 0c“
`
`
`
`
`Int. CLS .................................... .. ........ .. [52] Ujs' Cl‘ ' ' ' ' ‘ ' ' ' ' ' " 623/1; 140/71 R Duprat et a1, “Self—expanding Metallic Stants for Small
`
`[56]
`
`
`
`Fleld of sCarCh ................. .. References Cited
`
`R,
`
`
`
`Vessels: An Experimental Evaluation,” Ruth-010g”, Ilgawrence etl a115, “lPercutaneloeusi.l'indovizcgulagésgztgz
`
`U.S. PATENT DOCUMENTS
`
`lg‘gfnmema
`
`Va ‘mm’ a '0 “g”
`
`'
`
`'
`
`’
`
`2,701,559 2/1955 Cooper .
`3y49oi975 1/1970 Lightwood et a1- -
`3,635,215 1/1972 Shea et a]. ......................... .. 128/840
`4,140,126 2/1979 Choudhury .
`gaggle '
`4,503,569 3/1985 Dotter .
`4,512,333 4/1935 Ba1k° ct 31- -
`415531545 11/1985 Muss ‘1 al- '
`4’560’374 12/1985 ?émmerslag '
`4,580,568 4/1986 Gianturco .
`4,597,389 7/1986 Ibrahim e131. ............... .. 128/303 R
`4,649,922 3/1987 Wiktor .
`4,650,466 3/ 1987 Luther ................................. .. 604/95
`4,655,771 4/1987 wansten _
`4,665,918 5/1987 Garza et a1. .
`4,669,611 10/1987 Bowden .
`4,681,110 7/1987 Wiktor.
`4i693i7zl 9/ 1937 Ducheyne -
`4'733'665 3/1988 Pa‘mu -
`4’739'762 4/1988 p'ilmaz '
`4,800,882 1/1989 Gianturo ........................... .. 128/343
`4,830,003 5/1989 Wolff et al. ..
`..... .. 623/1
`4,856,516 8/1989 Hillstead
`..... .. 623/1
`
`4,886,062 12/1989 Wiktor . . . . . .
`
`. . . . . .. 623/1
`
`4,907,336 3/1990 Gianturco ........................... .. 29/515
`
`Sigwart et al, “Intravascular Stants to Prevent Occlu
`sion and Restenosis After Transluminal-Angioplasty,”
`New Englandjournal ofMedicine, VOL 316, No_ 12, Mm-~
`19,1981
`Schatz et a1, “Intravascular Stents for Angioplasty,”
`ca’d'o' PP- 2741, Dec- 1987
`Primary Examiner-David Isabella
`Assistant Examiner-Debra S. Brittingham
`Attorney, Agent, orFirm-Lockwood, Alex, FitzGibbon
`& c
`.
`“mmmgs
`~
`[57]
`ABSTRACI‘
`'
`Rad1ally expandable endoprostheses or stents are pro
`vided, as well as their method of manufacture. These
`stents include a plurality of adjacent generally circum
`ferential sections that are substantially axially posi
`tioned with respect to each other. At least one of the
`generally circumferential sections has a generally cir—
`cumferentially disposed expandable segment that im
`rt
`.
`f
`t. l
`d adial
`ndabilit to the
`Pa 5 “cum em‘ ‘a an r
`“P8
`y
`stem
`
`..
`
`16 Claims, 4 Drawing Sheets
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-1
`
`

`

`US. Patent
`
`July 13,1993
`
`Sheet 1 of 4
`
`5,226,913
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-2
`
`

`

`US. Patent
`
`July 13, 1993
`
`Sheet 2 of 4
`
`5,226,913
`
`‘7:1. g. 8..
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-3
`
`

`

`US. Patent
`
`July 1a, 1993
`
`Sheet ‘3 of 4
`
`5,226,913
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-4
`
`

`

`US. Patent
`
`July 13, 1993
`
`Sheet 4 of 4
`
`5,226,913
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-5
`
`

`

`1
`
`METHOD OF MAKING A RADIALLY
`EXPANDABLE PROS'I'HESIS
`
`5
`
`This application is a divisional, of copending applica
`tion(s) Ser. No. 548,101, ?led Jul. 5, 1990, now U.S. Pat.
`No. 5,092,877 which is a divisional of application Ser.
`No. 240,000, ?led Sep. 1, 1988 (now U.S. Pat. No.
`5,019,090).
`BACKGROUND AND DESCRIPTION OF THE
`INVENTION
`The present invention generally relates to endopros
`thesis devices, to a procedure for making same, and to
`the use thereof. More particularly, the invention relates
`to a generally tubular endoprosthesis that is radially
`expandable between a generally unexpanded insertion
`circumference and an expanded implantation circumfer
`ence which is greater than the unexpanded insertion
`circumference. Included are a plurality of generally
`circumferential sections, one or more of which includes
`one or more expandable segments that are bendable
`members which are generally collapsed when the endo
`prosthesis is in its generally unexpanded insertion orien
`tation and which are generally opened when the endo
`prosthesis is in its expanded implantation orientation.
`Endoprostheses are known for treating stenoses,
`stricture, aneurysm conditions and the like. An endo
`prosthesis device of this type, which is at times referred
`to as a stent, is typically placed or implanted by a me
`chanical transluminal procedure. Often a device of this
`type is percutaneously implanted within the vascular
`system to reinforce collapsing, partially occluded,
`weakened or abnormally dilated localized sections of a
`blood vessel or the like. Stents of this type can also be
`used in the urinary tract, the bile tract, the intestinal
`tract and the like. When endoprostheses or stents are
`used to treat a stenosis condition, typically such is done
`in association with a dilation element such as an angio
`plasty balloon. In this instance, the dilation element or
`balloon device opens the constriction, and a stent or the
`like is positioned thereat in order to prevent or at least
`substantially slow re-formation of the stenosis.
`One attribute of a stent is that it is radially compress
`ible and expandable so that it will easily pass through a
`blood vessel or the like when collapsed and will expand
`to its implanted size after the stenosis, aneurysm or the
`like has been reached. It is also desirable that a stent be
`generally ?exible throughout its length so that it is eas
`ily maneuverable through bends and curves of the
`blood vessel or the like. It is typically desirable that a
`stent or endoprosthesis have a substantial amount of
`open space so as to allow for endothelialization along its
`length, to minimize the foreign body response, and to
`minimize interference with collateral blood vessels and
`the like. While it is important that a stent or endopros
`thesis lodge securely into place at the desired location,
`it can be advantageous to have a stent that is removable
`through a transluminal percutaneous procedure, should
`removal be needed.
`Various currently known stent products have struc
`tures that are essentially coiled springs. When this type
`of spring stent is tightly coiled, its diameter is relatively
`small for insertion through a blood vessel or the like.
`When the coil is sprung or coiled more loosely, the stent
`assumes its expanded, ‘implantation orientation. Maass et
`al U.S. Pat. No. 4,553,545 is illustrative of this type of
`coiled spring stent or endoprosthesis. Multihelix or
`
`5,226,913
`2
`braided stents are also known. Stents of this general
`type suffer from poor maneuverability, and they are
`relatively thick walled and three dimensional. They are
`also difficult to remove once implanted, and they may‘
`exhibit numerous exposed, relatively sharp or jagged
`ends. Palmaz U.S. Pat. No. 4,733,665 is representative
`of an expandable stent of this general type. Gianturco
`U.S. Pat. No. 4,580,568 illustrates a percutaneous en
`dovascular stent formed of stainless steel wire that is
`arranged in a closed zig-zag pattern somewhat in the
`nature of a bookbinder spring. Such a structure is some
`what unsymmetrical, and it may be subject to reocclu
`sion due to the very large open space that is typically
`present between the wires of this type of device. An
`other type of stent is known as a Statz stent, and it
`includes a hypodermic tube with longitudinal slots
`etched into its body. While such a device has a high
`ratio of unexpanded to expanded diameter, it is a com
`paratively rigid, sharp-edged device which is difficult
`to maneuver through a tortuous path and is not easily
`removed in a transluminal manner.
`With many of these currently known stent structures,
`the axial length of the stent decreases as the circumfer
`ence of the stent increases, which is typically a disad
`vantage. For example, any such length reduction must
`be taken into consideration in selecting proper stent
`sizing for a particular implantation procedure. Also, this
`attribute of many prior stents requires the passage
`through the blood vessel or the like of a stent which is
`longer than the length actually needed for the implanta
`tion procedure being performed. This is a particularly
`dif?cult problem for procedures in which the stent must
`be passed through a pathway having twists or turns,
`especially for a stent structure that is not easily bend
`able.
`The present invention avoids the various de?ciencies
`of these types of prior art structures and provides im
`portant and advantageous features of endoprostheses or
`stents and the use thereof. In summary, the endopros
`thesis of this invention includes a plurality of generally
`circumferential sections that are generally adjacent to
`one another along their respective opposing generally
`circumferential edges. At least one of these generally
`circumferential sections has an expandable segment that
`imparts radial expandability to the generally circumfer
`ential section. The expandable segment is a bendable,
`elbow-like member that is bendable between a generally
`collapsed or closed orientation and a generally opened
`orientation and is capable of assuming bending orienta
`tions between one that is fully closed and one that is
`fully opened. By this structure, the endoprosthesis or
`stent has an unexpanded insertion circumference and an
`expanded implantation circumference, which is greater
`than the insertion circumference. In addition, this varia
`tion in circumference is achieved without substantially
`changing the axial length of the endoprosthesis or stent.
`The stent is made by a procedure that is relatively un
`complicated, and, generally speaking, the stent can be
`transluminally explanted if necessary.
`It is a general object of the present invention to pro
`vide an improved radially expandable, axially extending
`endoprosthesis of the type that can be transluminally
`implanted.
`Another object of the present invention is to provide
`an improved endoprosthesis or stent that can be con
`structed to have very large radial expansion capabilities.
`Another object of this invention is to provide an
`improved radially expandable axially extending endo
`
`25
`
`30
`
`35
`
`40
`
`45
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-6
`
`

`

`5,226,913
`3
`4
`.
`prosthesis that is extremely maneuverable and capable
`FIG. 11 is an elevational view of a step subsequent to
`of moving through a tortuous path.
`that shown in FIG. 10;
`Another object of the present invention is to provide
`FIG. 12 is an elevational view of a manufacturing
`an improved radially expandable axially extending en
`step subsequent to that illustrated in FIG. 11 and which
`doprosthesis that can, if desired, be transluminally ex
`shows a length of material suitable for winding on a
`planted by means of, for example, a snare lead or cathe
`mandrel in a generally helical manner in order to form
`the endoprosthesis of this embodiment;
`ter.
`Another object of the present invention is to provide
`FIG. 13 is a generally cross-sectional view illustrat
`an improved radially expandable axially extending en
`ing an early step in a procedure for implanting an endo
`doprosthesis which includes members that can be
`prosthesis according to the present invention, this par
`spaced apart or pointed in a manner that enhances lodg
`ticular procedure being especially suitable for an endo
`prosthesis having spring-like properties;
`ing of the endoprosthesis at its implanted site.
`Another object of the present invention is to provide
`FIG. 14 is a generally cross-sectional view illustrat
`an improved axially extending endoprosthesis that can
`ing an implantation step subsequent to that shown in
`be constructed in order to be radially expandable by an
`FIG. 13;
`expanding member or balloon of a catheter device and
`FIG. 15 is a generally cross-sectional view illustrat
`/or can be radially expandable due to spring-like prop
`ing an implantation step subsequent to that of FIG. 14;
`erties of the endoprosthesis.
`FIG. 16 is a generally cross-sectional view illustrat
`Another object of this invention is to provide an
`ing an implantation step subsequent to that illustrated in
`improved procedure for making an axially extending
`FIG. 15;
`and/or generally tubular endoprosthesis that is radially
`FIG. 17 is a generally cross-sectional view of an
`expandable.
`implantation step subsequent to that illustrated in FIG.
`Another object of the present invention is to provide
`16;
`an improved procedure and system for transluminally
`FIG. 18 is a generally cross-sectional view of an
`explanting an axially extending radially expandable
`implanted stent or endoprosthesis in accordance with
`endoprosthesis or stent.
`the present invention;
`'
`Another object of the present invention is to provide
`FIG. 19 is an elevational view of an endoprosthesis
`an improved radially expandable endoprosthesis that
`and distal end of a balloon catheter for an implantation
`substantially avoids the presentation of any frayed
`procedure that is especially suitable for an endoprosthe
`edges and that generally maintains its axial length
`sis. according to the present invention that is con
`throughout various radial expansion positions.
`structed of a malleable-type of material;
`These and other objects, features and advantages of
`FIG. 20 is a generally cross-sectional illustration of
`this invention will be clearly understood through a
`the endoprosthesis and catheter of FIG. 19 positioned
`consideration of the following detailed description.
`within a blood vessel;
`FIG. 21 is a generally cross-sectional illustration of an
`BRIEF DESCRIPTION OF THE DRAWINGS
`implantation stage subsequent to that shown in FIG. 20;
`In the course of this description, reference will be
`FIG. 22 is a generally cross-sectional illustration of an
`made to the attached drawings, wherein:
`implantation stage subsequent to that shown in FIG. 21;
`FIG. 1 is a perspective view illustrating an early step
`FIG. 23 is a generally cross-sectional illustration of an
`in the procedure of making an endoprosthesis according
`implanted stent or endoprosthesis according to the pres
`to the present invention;
`ent invention;
`FIG. 2 is an elevational view illustrating a step subse
`FIG. 24 is a generally cross—sectional illustration of a
`quent to that shown in FIG. 1;
`snare catheter shown explanting a stent or endoprosthe
`FIG. 3 is an elevational view showing a manufactur
`sis‘ in accordance with the present invention; and
`ing step subsequent to that of FIG. 2, while also illus
`FIG. 25 is a generally cross-sectional illustration
`trating a substantially completed endoprosthesis in ac
`showing a further stage of the explantation procedure
`cordance with the present invention;
`illustrated in FIG. 24.
`FIG. 4 is a cross-sectional view along the line 4-4 of
`FIG. 3;
`FIG. 5 is an enlarged detail view of a portion of one
`end of the endoprosthesis shown in FIG. 3;
`FIG. 6 is a perspective view illustrating an early step
`in the procedure of making another embodiment of the
`endoprosthesis;
`FIG. 7 is an elevational view illustrating a step subse
`quent to that shown in FIG. 6, while also illustrating the
`con?guration of a portion of this endoprosthesis prior to
`its circumferential orientation;
`FIG. 8 is a perspective view illustrating an early step
`in the procedure of making a further embodiment of the
`endoprosthesis;
`FIG. 9 is an elevational view illustrating a step subse~
`quent to that shown in FIG. 8, while also illustrating the
`con?guration of a portion of this endoprosthesis prior to
`its circumferential orientation;
`FIG. 10 is an elevational view of an early step in the
`manufacturing procedure for still a further embodiment
`of the endoprosthesis;
`
`DESCRIPTION OF THE PARTICULAR
`EMBODIMENTS
`A radially expandable axially extending endoprosthe
`sis or stent is generally designated as 31 in FIG. 3, as
`well as in FIG. 4. The stent includes a plurality of gen
`erally circumferential sections 32. In this illustrated
`embodiment, each of the circumferential sections 32 are
`formed from the same continuous, helically wrapped
`length, such as the undulating length 33 shown in FIG.
`2.
`At least one of the circumferential sections 32 in
`cludes at least one expandable segment 34. Expandable
`segment 34 is a bendable member that typically includes
`one or more legs 35. Each leg 35 is bendably secured to
`the rest of the circumferential section 32 by a so-called
`living joint or hinge that is a unitary or integral compo
`nent of the leg 35 and the adjacent portion of the cir
`cumferential section 32. For example, in the embodi
`ment illustrated in FIGS. 1 through 5, each leg 35 is
`bendably joined to another leg 35 through an integral or
`
`50
`
`55
`
`60
`
`65
`
`20
`
`25
`
`30
`
`35
`
`40
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-7
`
`

`

`25
`
`5,226,913
`5
`6
`1
`living hinge 36 which has a generally arcuate shape.
`of a hook portion that readily loops or tucks into the
`When the stent 31 expands, the integral hinge 36 per
`integral hinge 36. It may be desirable in some embodi
`mits end portions 37 of the legs 35 to move farther
`ments to weld this hook to hinge 36.
`apart, thereby increasing the circumference and diame
`Regarding the embodiment shown in FIGS. 6 and 7,
`ter of the stent 31. Of course, the circumference and
`the mandrel around which the strand 39 is wound is a
`diameter of the stent 31 can be reduced by forces which
`substantially rectangular mandrel 44. As a result, the
`generally planar structure that is subsequently formed is
`move these end portions 37 closer to each other.
`an undulating length 45 that includes a plurality of legs
`An understanding of the manner in which the endo
`46 joined by a unitary or integral hinge or living hinge
`prostheses according to this invention, such as the stent
`47 that is typically less arcuate than the integral hinge
`31, can be made will be obtained from a consideration of
`36. This undulating length 45 is then formed into an
`FIGS. 1, 2 and 3. FIG. 1 shows a mandrel 38 that has a
`cross-sectional con?guration that is somewhat oval in
`endoprosthesis or stent by helically winding same on a
`shape. Mandrel 38 can, for example, be a circular tube
`structure such as the cylindrical mandrel 41.
`or rod that has been ?attened on two opposing longitu
`Another embodiment of the endoprosthesis or stent is
`dinal portions in order to provide a cross-section that is
`made in a manner generally illustrated in FIGS. 8 and 9.
`generally rectangular in shape, with two opposing end
`Here, the mandrel is a generally lens-shaped mandrel 51
`portions thereof being arcuate or rounded. The mandrel
`which has a transverse cross—section that can be de
`is preferably composed of a malleable metal such as
`scribed as de?ning two convex surfaces positioned in
`back-to-back relationship with each other. Much in the
`copper of the like.
`A strand 39 of wire or other material, as generally
`same manner as the other embodiments, the elongated
`20
`discussed elsewhere herein, is generally tightly wound
`strand 39 is wound around the lens-shaped mandrel 51
`and then preferably heat annealed. The mandrel 51 is
`over the mandrel to the extent that the strand 39 takes
`subsequently moved therefrom, and the wound strand
`on a cross-sectional shape along the lines of that of the
`39 is rendered substantially uni-planar in order to form
`mandrel 38. Preferably, this winding is done in a manner
`undulating length 52 that is suitable for forming into a
`such that there is a substantial spacing between each
`individual wind of the strand 39. Generally speaking,
`stent by wrapping around the mandrel 41.
`Another embodiment illustrating the manufacture of
`the tighter the wind and the thinner the mandrel, the
`closer will be the spacing between the expandable seg
`an endoprosthesis or stent in accordance with this in
`ments 34 of the completed stent 31. After this winding
`vention is generally illustrated in FIGS. 10, 11 and 12. A
`has been completed, the wound strand 39 on the man
`strand is_ wound around a small-diameter mandrel 53
`drel 38 is preferably heat annealed using a conventional '
`which is circular in cross-section. In this case, the strand
`annealing process for the type of wire used.
`is formed into a tightly wound helix 54. Thereafter, the
`After this winding and annealing procedure has been
`mandrel 53 is removed, and the strand is formed into a
`more loosely wound helix 55. For example, the helix 55
`completed, the mandrel 38 is removed from the wound
`can be elongated such that the pitch angle is less than
`strand 39. Removal of the wound strand is facilitated by
`axially stretching the malleable mandrel to effectively
`approximately 60". This helix 55 is then flattened gener
`ally in the manner previously discussed, for example to
`reduce its diameter. The wound strand 39 is then sub
`jected to flattening forces so that the three-dimensional
`10 tons in a pneumatic press, in order to form a gener
`ally uni-planar undulating length 56. If desired, the
`wound strand 39 is transformed into a generally planar
`shape such as that of the undulating length 33 shown in
`length 56 can be axially compressed in a contained mold
`to the desired pitch angle. Length 56 is suitable for
`FIG. 2. These forces may be applied by an suitable
`winding around cylindrical mandrel 41 in order to
`means. For example, the wound strand 39 can be com
`pressed between two planar surfaces, during which
`thereby form an endoprosthesis or stent.
`procedure, portions of the wound strand 39 are twisted
`Stents illustrated herein are typically capable of mov
`until the generally uni-planar undulating length 33 is
`ing through a tortuous path that may be encountered in
`formed. This length has a generally sinusoidal charac
`vascular system implantation. Such stents can be easily
`axially bent over a relatively small radius without dam
`ter.
`age or high bending resistance.
`In order to complete formation of the stent 31 illus
`trated in FIG. 3, the undulating length 33 is then
`It should be appreciated that in the illustrated em
`bodiments, each circumferential section 32 is generally
`wound, in a generally helical manner, around a substan
`tially cylindrical mandrel 41, as is generally illustrated
`identical. It is also possible within the spirit of the inven
`in ‘FIG. 3. This generally helical wrapping procedure
`tion to provide circumferential sections that are not this
`uniformly shaped. For example, the circumference of
`continues until the desired number of circumferential
`adjacent sections can differ in order to form a stent that
`sections are formed in order to provide a stent 31 of a
`desired length. It may, depending upon the type of wire
`is not strictly shaped in the nature of a right cylinder.
`For example, tapered, truncated cone-shaped stents or
`used, be necessary to heat anneal the helical winding of
`FIG. 3.
`stepped stents can be provided. In addition, in some
`With reference to FIG. 5, this winding procedure
`applications, it can be suitable to include circumferen
`that is generally illustrated in FIG. 3 includes proceed
`tial sections that are not composed entirely of expand
`able segments, but instead could include non-expanda
`ing in a manner so as to avoid the presentation of any
`ble portions that are joined by expandable segments. It
`loose ends in the completed stent 31. This is readily
`accomplished by formed the strand 39 and the undulat
`also may be possible to provide stents within the spirit
`ing length 33 so that each end circumferential section 42
`of the present invention which include one or more
`has a free end 43 that readily hooks onto an adjacent
`circumferential sections that form a stent device with
`out proceeding with helical winding around cylindrical
`portion of the stent 31, such as an integral hinge 36 of
`65
`the circumferential section 32 that is adjacent to and
`mandrel 41 or the like.
`‘inwardly spaced from the end circumferential section
`It is also possible to provide a stent that has a gener
`42. The free end 43 illustrated in FIG. 5 is in the nature
`ally bifurcated structure for use in situations in which
`
`30
`
`45
`
`50
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-8
`
`

`

`5,226,913
`8
`7
`6111, as desired. Then, the balloon 67 can be pressurized
`the stenosis, aneurysm or the like that is to be treated is
`in order to further implant the stent 31 and in order to
`at a branching location within the vascular system or
`further dilate the lesion as desired so as to form a treated
`the like. Such a bifurcated stent structure can be
`formed, for example, by joining portions of the oppos
`lesion 61b which remains after the catheter 63 is re
`moved, as is generally shown in FIG. 18.
`ing ends of two different unitary stents in order to pro
`FIGS. 19 through 23 show an arrangement that is
`vide a total structure that is bifurcated, Y-shaped or the
`especially suitable for non-elastic stents in which the
`like. It should also be appreciated that the stent can be
`expandable segments thereof are made of malleable
`composed of a plurality of helical strands in a parallel or
`antiparallel con?guration.
`material. With reference to FIGS. 19 and 20, a stenosis
`The materials out of which stents according to the
`or lesion 61 within blood vessel 62 is transluminally
`present invention can be made, and especially the ex
`reached by a balloon catheter 71 having a stent 31 over
`pandable segments thereof, fall into two general catego
`lying the collapsed balloon 72 of the catheter 71. The
`ries. The material can be either elastic or generally
`balloon 72 is then expanded in a well-known manner, at
`inelastic. Examples of elastic materials include spring
`which time the stent 31 is also expanded by opening the
`steels, stainless steel, Nitinol, Elgiloy, an alloy known as
`expandable segments thereof. An intermediate dilation
`NP36N, and the like. Generally inelastic materials can
`position is shown in FIG. 21, and an initially dilated
`be characterized as being malleable. Included are tanta
`lesion 61a is shown therein. FIG. 22 shows additional
`lum, titanium, silver, gold, and annealed versions of the
`dilation by the balloon 72, and the thus treated lesion
`elastic materials described herein. Polymers may also be
`61b is also shown. After this stage is achieved, the bal
`used, such as polyether sulfone, polyirnide, polycarbon
`loon catheter 71 is removed, as shown in' FIG. 23.
`ate, polypropylene, ultra high molecular weight poly
`The stent 31 remains in place as generally illustrated
`ethylene, carbon ?ber, Kevlar, and the like. It is also
`in FIG. 23 because the malleable material (or for that
`possible to coat these materials with porous or textured
`matter an elastic material) exerts a hoop stress when it is
`surfaces for cellular ingrowth and the like or with non
`expanded to the size illustrated in FIG. 23 such that it
`thrombogenic agents such as pyrolytic carbon, heparin,
`will not collapse by inwardly directed radial forces
`hydrogels, Te?on materials, silicones, polyurethanes
`presented by the treated lesion and vessel wall or the
`and the like. The stents can be treated so that drugs can _
`like. In other words, the hoop stress of the expanded
`be eluted therefrom. It is also possible that certain stents
`stent is greater than the hoop forces exerted by the
`may be made of biodegradable materials. In any event,
`passageway within which the stent is implanted. In
`the stent material, of course, is to be biocompatible. It
`addition, the force required to open the collapsed stent
`should also be appreciated that the strand of stent mate
`by the balloon is less than the hoop force provided by
`rial can be round in cross-section as is typical of wires,
`the balloon. In other words, the hoop stress of the col
`or it can be ?at‘or rectangular in cross-section, for ex
`lapsed or unextended stent is less than that of the hoop
`ample.
`force provided by the pressurized balloon of the cathe
`FIGS. 13 through 18 illustrate an implantation proce
`ter. One feature that can contribute to the advantageous
`dure and an insertion system that is particularly suitable
`hoop stress properties of the malleable stents of the type
`for stents that are constructed of an elastic material such
`illustrated in the drawings is the ability of the stent to
`as spring steel. A stenosis or lesion 61 is shown within a
`expand well beyond that needed to effect the dilation
`blood vessel 62. The stent 31 is positioned on a balloon
`procedure. For example, a typical dilation procedure
`catheter, generally designated as 63. An introducer tube
`and stent extension is one in which the fully extended
`or plunger 64, or a similar stop-providing structure, is
`dilating diameter or circumference is approximately
`positioned along the outside surface of the catheter tube
`three times the insertion or collapsed diameter or cir
`65. The stent 31 is located distally of the member 64,
`cumference. With stent structures such as those illus
`and a sheath 66 holds the stent 31 in a generally com
`trated in the drawings, the amount of possible expansion
`pressed state during which the expandable segments of
`can be on the order of two to twenty times, depending
`the stent 31 are generally collapsed or closed. FIG. 13
`upon the length of each undulation and the distance
`further shows the balloon 67 of the catheter in a mode
`between the legs. This feature, together with the malle
`in which it is exerting outwardly radially directed
`ability of the particular material utilized, tends to re
`forces on the lesions in order to dilate same to provide
`duce the hoop force that is needed to expand the stent to
`a wider opening as generally illustrated in FIG. 14 in
`about three times its insertion or collapsed con?gura
`order to thereby generally reduce the overall extent of
`tion.
`the lesion to the general con?guration of initially
`FIGS. 24 and 25 illustrate a stent withdrawal proce
`treated lesion 61a. At this time, the balloon 67 is col
`dure and a snare catheter system that can be used to
`lapsed, and the catheter 63 is moved in a distal direction
`remove or explant implanted stents according to the
`so that the collapsed stent 31 is generally positioned
`present invention. A snare catheter, generally desig
`within the lesion 61a. Next, as illustrated in FIG. 15, the
`nated as 74, is illustrated. An elongated member 75 is
`sheath 66 is withdrawn by moving same in a generally
`slidably positioned within a catheter body 76. Elon
`proximal direction, and the stent 31 is released from the
`gated member 75 includes a hook member 77 at its distal
`sheath 66. This release can be such that adjacent cir
`end. When extended into the stent 31, the hook member
`cumferential sections of the stent expand in a generally
`77 snares a portion of the stent 31. A suitable control
`sequential manner, which is generally illustrated in
`structure, such as the puller assembly 78 illustrated is
`FIG. 15.
`manipulated in order that the hook member moves in a
`After this procedure is completed, the entire stent 31
`proximal direction, with the result that the stent begins
`has been sprung, and it springingly engages the dilated
`to uncoil and is opened to such an extent that it can be
`lesion 61a, which is generally illustrated in FIG. 16.
`passed through the blood vessel 62 or the like until it is
`Thereafter, as seen in FIG. 17, the catheter 63 can be
`totally removed from the body by continued movement
`moved in a generally proximal direction until the bal
`of the elongated member 75 in the proximal direction.
`loon 67 is again generally aligned with the dilated lesion
`
`60
`
`55
`
`65
`
`25
`
`35
`
`40
`
`W.L. Gore & Associates, Inc.
`Exhibit 1004-9
`
`

`

`- 5,226,913
`
`10
`4. The method according to claim 1, wherein said
`providing step inclu