O
`
`United States Pilt?llt [19]
`Myers et al.
`
`USOO5700285A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,700,285
`Dec. 23, 1997
`
`[54] INTRALUMINAL STENT GRAF'I‘
`
`[75] Inventors: David J. Myers, Camp Verde; James
`D. Lewis, Flagsta?‘; Wayne D. House,
`
`all ofAriL
`
`[73] Assignee: W. L. Gore & Associates, Inc.,
`.
`Newark, Del‘
`
`[21] Appl. No.: 477,051
`[22] Filed:
`In 7, 1995
`
`Related US. Application Data
`
`[62] Division of S61‘. NO. 109,214, Aug. 1a, 1993, abandoned.
`[51] Int. Cl.6 ................................ .. A61F 2/06; A61F 2/04
`[52] US. Cl. ................................ .. 623/1; 623/12; 606/198
`[53] Field of Search ................................... .. 606/198, 195,
`606/191; 623/1’ 12
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,300,244 11/1981 Bokros.
`
`4,512,228 4/1985 Balko et al. .
`4,681,110
`7/1987 Wiktor .
`4,740,207 4/1988 Kmamer
`4,776,337 10/1933 Palmaz .
`
`4,954,126 9/1990 wins/en.
`5,107,852 411992 Davidson et a1. .
`5,254,113 10/1993 wlak '
`5,282,823 211994 Schwartz et a]. .
`5,282,824 Z1994 Giantumo .
`
`Primary Examiner—Michael B1112
`Assistant Examiner—Nancy Connolly Mulcare
`Attorney Agent, or Firm-Wayne D. House
`
`ABSTRACT
`[57]
`A tubular innaluminal graft in the form of a tubular dia
`me?ically adiusmblc Sim having a tllbular coming of
`Porous expand“ P01)"'=‘Ia?\l<>f<>¢?lylcue which is less than
`0.10 mm thick. The covering may be on the exterior surface
`of the stent, or on the interior surface of the stent, or both.
`The covering may be a?ixed to the stent by an adhesive
`which is preferably ?uorinated ethylene propylene.
`
`18 Claims, 4 Drawing Sheets
`
`35
`
`43
`10
`
`45
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-1
`
`

`

`US. Patent
`
`Dec. 23, 1997
`
`Sheet 1 0f 4
`
`5,700,285
`
`/IO
`
`FIG. I
`
`I
`
`/_____,.
`
`l-
`
`I |
`
`"
`
`l2
`
`u
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-2
`
`

`

`US. Patent
`
`Dec. 23, 1997
`
`Sheet 2 of 4
`
`5,700,285
`
`|3
`
`|3
`
`:1
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-3
`
`

`

`US. Patent
`
`Dec. 23, 1997
`
`Sheet 3 of 4
`
`5,700,285
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-4
`
`

`

`US. Patent
`
`Dec. 23, 1997
`
`Sheet 4 of 4
`
`5,700,285
`
`7:
`7. A.
`.H ..., t v: .. z
`
`FIG.
`
`7
`
`FIG
`. 8
`
`95
`
`0
`O 6 O - O
`Q6000...‘
`
`v “ 7.‘... .
`,
`0
`O
`3,053.. 040103).‘
`A
`
`93
`
`FIG. 9
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-5
`
`

`

`1
`INTRALUMINAL STENT GRAFT
`
`5,700,285
`
`This application is a division of application Ser. No.
`08/109,214, ?led Aug. 18, 1993 (status:abandoned).
`
`FIELD OF THE INVENTION
`This invention relates to the ?eld of intraluminal grafts
`and particularly to thin-wall intraluminal grafts useful as an
`inner lining for blood vessels or other body conduits.
`
`10
`
`BACKGROUND OF THE INVENTION
`Conventional vascular grafts have long been used for
`vascular repair in humans and animals. These devices are
`typically ?exible tubes of woven or knitted polyethylene
`terephthalate or of porous polytetra?uoroethylene
`(hereinafter P'I'FE). Grafts of biological origin are also used,
`these being typically ?xed human umbilical or bovine
`arteries. These conventional vascular grafts usually require
`invasive surgical methods that expose at least both ends of
`the segment of vessel to be repaired. Frequently it is
`necessary to expose the entire length of the vessel segment
`These types of repairs consequently cause major trauma to
`the patient with corresponding lengthy recovery periods and
`may result in occasional mortality.
`Alternative methods have evolved which use intraluminal
`vascular grafts in the form of adjustable stent structural
`supports, tubular grafts or a combination of both. These
`devices are preferably remotely introduced into a body
`cavity by the use of a catheter type of delivery system.
`Alternatively they may be directly implanted by invasive
`surgery. The intent of these methods is to maintain patency
`after an occluded vessel has been re-opened using balloon
`angioplasty, laser angioplasty, atherectomy, roto-ablation,
`invasive surgery, or a combination of these treatments.
`Intraluminal vascular grafts can also be used to repair
`aneurysmal vessels, particularly aortic arteries, by inserting
`an intraluminal vascular graft within the aneurysmal vessel
`so that the prosthetic withstands the blood pressure forces
`responsible for creating the aneurysm.
`Intralurninal vascular grafts provide a new blood contact
`ing surface within the lumen of a diseased ltying vessel.
`Intraluminal grafts are not, however, limited to blood ves
`sels; other applications include urinary tracts, biliary ducts,
`respiratory tracts and the like.
`If the intraluminal graft used is of thin enough wall and
`adequate ?exibility, it may be collapsed and inserted into a
`body conduit at a smaller diameter location remote from the
`intended repair site. A catheter type of delivery system is
`then used to move the intraluminal graft into the repair site
`and then expand its diameter appropriately to conform to the
`inner surface of the living vessel. Various attachment meth
`ods including the use of adjustable stents may be used to
`secure the intraluminal graft at the desired location without
`the necessity of invasive surgery.
`Intraluminal vascular grafts were suggested as early as
`1912 in an article by Alexis Carrel (Results of the permanent
`intubation of the thoracic aorta. Surg., Gyn and Ob.
`1912;15:245-248). U.S. Pat. No. 3,657,744 to Ersek
`describes a method of using one or more adjustable stents to
`secure a ?exible fabric vascular graft intralurninally, the
`graft and stent having been introduced distally and delivered
`to the desired position with a separate delivery system.
`Choudhury, U.S. Pat. No. 4,140,126, describes a similar
`method of repairing aortic aneurysms whereby a polyethyl
`ene terphthalate vascular graft is ?tted at its ends with metal
`
`25
`
`30
`
`45
`
`55
`
`65
`
`2
`anchoring pins and pleated longitudinally to collapse the
`graft to a size small enough to allow for distal introduction.
`Rhodes, U.S. Pat. No. 5,122,154 and Lee, U.S. Pat. No.
`5,123,917, describe endovascular bypass grafts for intralu
`minal use which comprise a sleeve having at least two
`diametrically-expandable stents. Rhodes teaches that the
`sleeve material is to be made of conventional vascular graft
`materials such as GORE-TEX® Vascular Graft (W. L. Gore
`& Associates, Inc., Flagstaff Ariz.) or Impra® Graft (Impra,
`Inc. Tempe Ariz). Both the GORE-TEX Vascular Gra? and
`Impra Graft are extruded and longitudinally expanded PI'FE
`tubes. Additionally, the GORE-TEX Vascular Graft pos
`sesses an exterior helical wrapping of porous expanded
`PI'FE ?lm. The di?iculty with the use of either the GORE
`TEX Vascular Graft or the Irnpra graft as the sleeve com
`ponent is that the relatively thick, bulky wall of the extruded,
`longitudinally expanded PTFE tubes limits the ability of the
`tube to be contracted into a small cross-sectional area for
`insertion into a blood vessel. For example, the wall thickness
`of a 6 mm inside diameter Thin Walled GORE-TEX Vas
`cular Graft is typically 0.4 mm. The thinness of the wall is
`limited by the di?iculty of manufacturing an extruded,
`longitudinally expanded tube having a thin wall of uniform
`thickness.
`
`SUMMARY OF THE INVENTION
`The present invention is a tubular intraluminal graft
`comprising a tubular, diametrically adjustable stent having
`an exterior surface, a luminal surface and a wall having a
`multiplicity of openings through the wall, and further having
`a tubular covering of porous expanded PTFE ?lm a?ixed to
`the stent, said covering being less than about 0.10 mmthiek.
`Porous expanded PI'FE ?lm has a rniu'ostructure of nodes
`interconnected by ?brils and is made as taught by U.S. Pat.
`Nos. 3,953,566; 4,187,390 and 4,482,516. As will be
`described further, the ?brils may be uniaxially oriented, that
`is, oriented in primarily one direction, or multiaxially
`oriented, that is, oriented in more than one direction. The
`term expanded is used herein to refer to porous expanded
`P'I'FE. The terms expand, expanding and expandable are
`used herein to refer to diametrically adjustable intraluminal
`stents. More speci?cally, the term balloon-adjustable refers
`to stents of the Palmaz type as taught by U.S. Pat. No.
`4,776,337 which typically require a balloon catheter to
`increase the diamder of the stent within a blood vessel. The
`term self-expanding refers to stents which increase in diam
`eter by various other means. Stents of this type include stents
`of braided wire made as taught by Wallsten, U.S. Pat. No.
`4,544,771; and stents of formed wire made as taught by
`Gianturco, U.S. Pat. No. 4580,568. Stents of this type
`expand to a larger diameter after being released from a
`constraining force which restricts them to a smaller diam
`eter. Self-expanding stents also include stents formed from
`Nitinol wire made as taught by PCI‘ US 92103481. These
`stents expand in diameter when exposed to a slight increase
`in temperature.
`The tubular covering of porous expanded P'TFE ?lm may
`be a?ixed to either the exterior surface or the luruinal surface
`of the stent. Alternatively, a ?rst tubular covering of porous
`expanded PI‘FE ?lm may be a?ixed to the exterior surface
`of the tubular diametrically adjustable stent and a second
`tubular cova'ing of porous expanded PI'FE ?lm may be
`af?xed to the luminal surface of the tubular diametrically
`adjustable stent. The ?rst and second tubular coverings of
`porous expanded PI'FE ?lm may be a?ixed to each other
`through the openings through the wall of the stent.
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-6
`
`

`

`3
`Theprx‘ous expandedl’I‘FE?lmmaybeat?xedtothe
`‘eat with an adhesive. The adhesive may be a thermoplastic
`adhesive and mac p'eferably a thermoplastic ?uoropolymer
`adhesive such as ?uorinated ethylene propylene (hereinafter
`PE) a’ pq'?uoroalkoxy (hereinafter PFA). Whue ?rst and
`second tubular coverings of expanded PTFE ?lm are a?ixed
`to each other through the multiplicity of openings in the stent
`wall, the two coverings may be a?ixed by heating them
`hove the u'ystalline melt point of the PTFE ?lm adequately
`to cause them to thu'mally adhere, or alternatively they may
`beat?xedbyanadhesivesuchasFEP.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a side view of a typical diametrically adjustable
`dent.
`FIG. 2 is an enlarged schematic representation of the
`mierostructure of porous expanded PTFE film having a
`miaostructure with uniaxially-ouiented ?brils as used to
`construct Examples 1 and 3.
`ms. 3A and 313 describe enlarged schematic represen
`tations of the miu'ostrucmre of porous expanded PTFE ?lm
`living miu'ostructm'es of multiaxially-oriented ?brils as
`tied to construct Example 2.
`FIG. 4 is a transverse cross section of the stent of Example
`1 having a huninal layer of porous expanded PTFE ?lm with
`longitudinally-oriented ?brils and an exterior layer of porous
`upended PTFE ?hn with circumferentially-oriented ?brils.
`FIG. 5 is a transverse cross section of the stent of Example
`2 having a luminal layer of pcxous expanded PI'FE ?lm with
`liaxially-oriented ?brils.
`FIG. 6 is a transverse cross section of the stent of Example
`3 having an extqior layer of porous expanded PTFE ?lm
`with drcumferentially-aiented ?brils.
`PK}. 7 describes a method of collapsing a previously
`outwardly adjusted balloon-expandable stent.
`FIG. 8 describes the ?tting of a single tubular sleeve to
`both the exterior and luminal surfaces of a stent.
`FIG. 9 describes the removal a covered, braided wire stent
`d‘ the self-expanding type from a manufacturing mandrel by
`evq'ting the braided wire, thq'eby placing the covering on
`the luminal surface of the stent.
`DETAIIED DESCRlPI‘ION OF THE
`INVENTION
`FIG. 1 is a side view of a typical diametrically adjustable
`ment. The stent is shown as it would appear implanted into
`a body conduit with its diameter adjusted beyond the col
`lqaaed pro-implantation diameter. While the stent shown is
`made from metal wire, a perforated sleeve having perfora
`tions of suitable shape, size and quantity may also be used.
`Various suitable stents are described by US. Pat. No.
`4,776,337 to Palmaz and PC!’ US 92103481 to Hess. These
`deals my be made from implantable metals such as
`t'lanium, stainless steel, or Nitinol.
`The stent may be provided with an exterior covering of
`ptIous expanded PTFE ?lm, or a luminal covering of porous
`eapndedPI‘FE?lmawithboth exteriorandluminal
`covu'ingr. Uniaxially-oriented ?lms having a mierostructure
`d uniaxially-aiented ?ta'ils wherein substantially all of the
`?rila are oriented parallel to each other may be used.
`MuIiaxially-oriented ?lms having a microstrumrre of biaxi
`dly or multiaxially-oriented ?brils wherein the ?brils are
`aieled in at least two directions which are substantially
`pupendimlar to each other may also be used.
`FIG. 2 describes an enlarged schematic representation of
`the microstructm'e of nodes 11 connected by ?brils 12 of a
`
`4
`?lm 20 wherein the uniaxially-oriented ?brils 12 are sub
`stantially parallel to each other. FIGS. 3A and 313 describe
`enlarged schematic representations of alternative micro
`structures of porous expanded PTFE ?lms that may also be
`used for making the present invention. These microstruc
`tures have nodes interconnected by ?brils wherein the ?brils
`are oriented in at least two directions which are substantially
`perpendicular to each other. FIG. 3A describes a microstruc
`ture 30 of nodes 11 and ?brils 13 and is wherein the ?brils
`13 and 15 are biaxially-oriented ?brils which are oriented in
`two different directions that are substantially perpendicular
`to each other. Those rnicrostructures may contain some
`?brils 17 which are not oriented in the two dilferent direc
`tions. FIG. 3B describes another alternative microstructure
`35 wherein the ?brils 21 are multiaxially-oriented ?brils
`oriented in virtually all directions within the plane of the
`sheet material. Either of these ?lms may be made by having
`been expanded two directions that are perpendicular to each
`other. The microstructure 30 of multiaxially-oriented ?brils
`21 may also have been made by being expanded in more
`than two directions as shown by FIG. 3B. The manufacture
`of these ?lms is taught by US. Pat. Nos. 3,953,566; 4,198,
`390 and 4,482,516.
`The ?bril lengths of the porous expanded PTFE ?lms
`referred to herein were estimated mean values obtained by
`examining scanning electron photomicrographs of these
`?lms. For multiaxially-oriented ?lms, these estimates
`included consideration of ?brils oriented in all directions.
`The mean ?bril lengths of the ?lms used to construct the
`intraluminal grafts of the present invention are preferred to
`be within the range of about 5 to about 120 microns,
`although ?bril lengths beyond this range may also be useful.
`Wall thickness measurements of intraluminal graft stent
`coverings were determined by cutting away a portion of the
`covering that covered an opening through the stent wall. The
`thickness of the sample portion was measured by placing the
`sample portion between the pads of a Mitutoyo model no.
`804-10 snap gauge having a part no. 7300 frame, and gently
`easing the pads into contact with the sample portion until the
`pads were in full contact with the sample portion under the
`full force of the spring-driven snap gauge pads. Film density
`measurements were based on the bulk volume of m ?lm
`sample using the snap-gauge thickness measurement.
`The following examples of intraluminal stent grafts are
`intended to be illustrative only and are not intended to limit
`the scope of the invention to only the constructions
`described by these examples.
`
`EXAMPLE 1
`
`A Nitinol wire stent l0 (Nitinol Medical Technologies,
`Boston, Mass.) of the type described by FIG. 1 was provided
`with both a luminal covering and an exterior covering of
`expanded PI‘FE ?lm. This 3 cm long stent was formed from
`0.25 mm diameter Nitinol wire into a tubular shape of
`interlocking hexagons. The luminal and exterior coverings
`were both made from a uniaxially-oriented ?lm having
`?brils oriented substantially in a single direction wherein the
`?brils were all substantially parallel to each other. The
`luminal covering was provided with the ?brils oriented
`parallel to the longitudinal axis of the tubular stent; the
`exterior covering was provided with the ?brils oriented
`substantially circumferential to the tubular stent. The ?lm
`used for both the luminal and exterior coverings was a
`porous expanded PTFE ?lm having a discontinuous, porous
`coating of PEP applied to one side of the porous expanded
`PTFE ?lm. Examination of the FEP coated side of the ?lm
`
`5,700,285
`
`10
`
`25
`
`30
`
`35
`
`45
`
`50
`
`65
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-7
`
`

`

`5
`by scanning electron microscopy revealed FEP on only
`small portions of the nodes and ?brils at the surface of the
`?lm. It was estimated that less than 10% of the available
`node and ?bril surface area exposed at the surface of the ?lm
`was covered by FEP. The presence of the FEP adhesive thus
`had little or no adverse etfect on the porosity of the porous
`PTFE ?lm.
`The FEP-coated porous expanded PI‘FE ?lm was made
`by a process which comprises the steps of:
`a) contacting a porous PTFE ?lm with another layer
`which is preferably a ?lm of FEP or alternatively of
`another thermoplastic polymer;
`b) heating the composition obtained in step a) to a
`temperature above the melting point of the thermoplas
`tic polymer;
`c) stretching the heated composition of step b) while
`maintaining the temperature above the melting point of
`the thermoplastic polymer; and
`d) cooling the product of step c).
`In addition to FEP, other thermoplastic polymers includ
`ing thermoplastic ?uoropolymers may also be used to make
`this coated ?lm. The adhesive coating on the porous
`expanded P'I'FE ?lm may be either continuous (non-porous)
`or discontinuous (porous) depending primarily on the
`amount and rate of stretching, the temperature during
`stretching, and the thickness of the adhesive prior to stretch
`mg.
`The discontinuously FEP-coated porous expanded PI‘FE
`?lm used to construct this example was of about 0.01 mm
`thiclmess and had a density of about 0.3 g/cc. The micro
`structure of the porous expanded PI‘FE contained ?brils of
`about 50 micron mean ?bril length.
`A 3.0 cm length of ?lm 20 having uniaxially-oriented
`?brils was wrapped as a single layer 41 around a hollow,
`tubular, 1.5 cm outside diameter mandrel 43 of non-porous
`PI'FE to form a seam 45 as described by the cross section of
`FIG. 4. The seam edges 45 overlapped as shown by about 3
`mm. The ?brils of the ?lm were oriented parallel to the
`longitudinal axis of the mandrel; the FEP-coated side of the
`?lm faced away from the surface of the mandrel. The Nitinol
`stent was carefully ?tted over the ?lm-wrapped port,on of
`the mandrel. The 3 cmlength of the stent was centered over
`the 3.0 cm length of ?lm-wrapped mandrel. The stent was
`then provided with an exterior covering 47 of a 3.0 cm wide
`tape of the ?lm described above by wrapping the tape
`circumferentially around the exterior surface of the mandrel
`so that the edges of the circumferentially-wrapped tape
`overlapped by about 3 mm to form seam 49. The circum
`ferentially wrapped covering was oriented so that the FEP
`coated side of the tape faced inward in contact with the
`exterior surface of the stent and the outward facing FEP
`coated surface of the luminal layer of ?lm exposed through
`the openings in the stent. Except for the overlapped seam
`edges 49, the circumferentially-wrapped covering was only
`one ?lm layer thick. The uniaxially-oriented ?brils of the
`microstructure of the circumferentially-wrapped tape were
`circumferentially-oriented about the exterior stent surface.
`The ?lm-wrapped mandrel assembly was placed into an
`oven set at 360° C. for a pm'iod of 4 minutes after which the
`?lm-wrapped mandrel was removed from the oven and
`allowed to cool. Following cooling to approximately ambi
`ent temperature, the mandrel was removed from the ?lm
`wrapped stent. The amount of heat applied was adequate to
`melt the FEP-coating on the porous expanded Pl‘FE ?hn and
`thereby cause adjacent layers of ?lm to adhere to each other.
`Thus the luminal layer of ?lm was adhered to the exterior
`
`35
`
`45
`
`55
`
`5,700,285
`
`10
`
`6
`circumferentially wrapped layer through the openings
`between the adjacent wires of the stent. The combined
`thickness of the luminal and exterior coverings was about
`0.025 mm.
`The ?hn-covered stent was then chilled in a bath of ice
`water while being rolled between human ?ngers applying
`compression diametrically across the stent. This reduced the
`outside diameter of the stent to about 0.3 cm. The collapsed
`stent was then heated by immersion in about 40° C. water,
`thereby increasing the stent diameter to about 1.5 cm. The
`?lm covering showed no visible advu'se effects from the
`process of shrinking and increasing the stent diameter.
`
`EXAMPLE 2
`
`A Nitinol wire stent of the same type used for Example 1
`was provided with a luminal covering of a porous expanded
`P'I'FE ?lm having a microstructure of biaxially-oriented
`?brils as shown by FIG. 3A. This was accomplished by
`wrapping a hollow tubular mandrel of non-porous PI‘FE
`with a layer of porous expanded PTFE ?lm having a
`continuous (non-porous) coating of FEP with the FEP
`coated side of the ?lm facing outwardly away from the
`mandrel SlIl'filCC. This ?lm was about 0.02 mm thick; the
`porous expanded PTFE had a microstructure of uniaxially
`oriented ?brils with the ?brils oriented circumferentially
`about the exterior surface of the mandrel. The Nitinol stent
`was carefully ?tted over the ?hn-wrapped portion of the
`mandrel. The mandrel assembly yes then placed into an oven
`set at 360° C. for four minutes. After removal from the oven
`and subsequent cooling, the mandrel was removed ?'om the
`stent leaving the wrapped ?lm adhered to the lmninal
`surface of the stent. This ?lm was then peeled from the
`luminal stent surface, leaving the FEP-coating and some
`small shreds of residual porous expanded P'I'FE adhered to
`the luminal surface of the stent wires. By removing the ?lm
`and leaving the FEP adhesive on the luminal stent surface,
`the ?lm served only as a release substrate for the application
`of the adhesive to the stent surface.
`As shown by FIG. 5, the mandrel 43 was then provided
`with a single layer 51 wrapping of a porous expanded P'I'FE
`?hn 35 having a microstructure of biaxially-oriented ?brils.
`This ?lm was of about 30 micron ?bril length, about 0.08
`mm thickness, about 0.3 g/cc density and did not have an
`FEP coating. The biaxially-or tented ?brils were oriented to
`be substantially parallel to the longitudinal axis of the
`mandrel and to'the circumference of the mandrel.
`The ?lm was overlapped adequately to form a 2 mm wide,
`longitudinally oriented searnline 45 parallel to the longitu
`dinal axis of the mandrel. A sheet of polyamide ?lm was
`temporarily placed over the sm'face of the seam and then
`contacted with the surface of a hand-held iron set at 400° C.
`to cause the PTFE ?lm seam edges to adhere to each other.
`Excess material beyond the 2 mm wide seam was trimmed
`away and discarded. The stent was again carefully ?tted over
`the ?lm-covered mandrel. The resulting assembly was
`placed into an oven set at 380° C. for three minutes and then
`removed and allowed to 0001, after which the mandrel was
`removed from the stent. The porous expanded P'I'FE ?lm
`appeared to be well adhered to the luminal surface of the
`wire stent by the FEP coating left from the ?rst, previously
`removed, layer of ?lm. The wall thickness of the PI'FE ?lm
`covering was about 0.08 mm.
`The ?hn-covered stent was then chilled in a bath of ice
`water while being rolled between human ?ngers applying
`compression diametrically across the stent. This reduced the
`outside diameter of the stent to about 0.3 cm. The collapsed
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-8
`
`

`

`5,700,285
`
`10
`
`25
`
`7
`tent was then heated by immersion in about 40° C. water,
`thaeby increasing ?re stent diameter to about 1.5 cm. ‘The
`?lm covering showed no visible adva-se e?ects from the
`pocess of shrinking and increasing the stent diameter.
`ECAMPLE3
`A Palmaz stent of the balloon-expandable type (part no.
`P830, Johnson & Johnson lnterventional Systems, Inc.,
`Wlr'en, NJ.) was adjusted from its collapsed outside diam
`d8 of 3.4 mm to an enlarged outside diameter of 8.0 mm by
`insu'ting a tapu'ed stainless steel mandrel followed by a
`straight 8.0 mm diameter stainless steel mandrel. This stent
`was then [Iovided with a single layer exterior wrapping of
`the same discontinuously PEP-coated porous expanded
`PI‘PE coating used for the exterior wrapping of the stent of
`Exanple 1. This was accomplished by wrapping the ?lm
`tout the exterior surface of the mandrel with the uniaxially
`triented ?lx'ils of the ?lm microstructure oriented parallel to
`the longitudinal axis of the stent. This exterior covering 61
`is described by ?re transverse cross section of FIG. 6. A2
`mm wide seam 45 was formed from the overlapped edges of
`20
`theporous expanded PTFE ?lm20 by temporarily placing a
`thin rhea of polyamide ?lm over these edges and applying
`he“ from a hand-held iron with a surface temperature of
`M 400° C. The ?lm-wrapped stent 65 was then placed
`into an oven set at 380° C. for 3 minutes, after which it was
`removed and allowed to cool. The ?lm appeared to be well
`allied to ?re extmior surface of the stent. The wall thick
`seas of the ?lm covering was about 0.01 mm. The enlarged
`lent was ?ren collapsed by the following process.
`A series d 20 cm long 6-0 sutures were tied individually
`to end! of the closed metal stent openings adjacent to one
`and of a stent. The ?lm-covered stent was provided with a
`temporary non-adhered additional wrapping of
`longitudinally-dented ?lm without FBI’ and having a
`microstnlcture of uniaxially-taiented ?brils. This temporary
`wrqrping was intended as a dry lubricant. As described by
`FIG. 7 which omits ?re exterior ?lm covering for clarity, the
`enlarged stent 71 was ?ren pulled by these sutures 77
`?lrough a tapu'ed die 75 of round cross section and 2.5 cm
`M, the die having a tapered ori?ce with a 9.5 mm
`tlameter bore at its entrance 78 and a 4.5 mm diameter bore
`I its exit 79. The result was that the stent was collapsed back
`I! m outside diameter of 4.5 mm. The lubricity of the
`tenmorarycovering ofporous expandedPI'FE?lmaidedin
`making it possible to pull the stent ?rrough the die. This
`wary covering was removed after completion of the
`collqrsing process. It is anticipated that the use of a tapered
`Ge having an appropriately sized, smaller diameter exit bore
`would result in collapsing the stent to its original collapsed
`dameter. The ?lm-covered stent was again enlarged to a
`tlameter of 8 m using a balloon catheter followed by a
`tape-ed stainless steel mandrel. The covering of porous
`expandedPI'FE?lmawearedtobefullyintactafter?re
`oollqssing and enlarging of the ?lm-covered stent.
`Stent coverings may be a?ixed to a stent surface by
`vlilions on ?ris method. Fm example, a tubular sleeve may
`be made from a ?lm of pta'ous expanded PI‘FE and inverted
`lmckinto itself and ?tted over the inner and outer surfaces
`dastentas shownbyFIG.8.’I‘heinner83andoute1-85
`pa'tions of the tubular sleeve 81 may be thermally adhered
`to each otha through ?re openings in the stent wall, or may
`be adhered to the stent surfaces by an adhesive such as FEP,
`(I may be a?ixed to the stent by suturing the open ends 87
`d the time together.
`
`50
`
`8
`approximate 1 mm overlap covering of porous expanded
`PTFE ?lm by helically wrapping the wire with a narrow tape
`cut from a sheet of porous expanded PTFE ?lm. The tape
`used was 6 mm wide, 0.01 mm thick, 0.3 g/cc density, and
`had uniaxially-oriented ?brils of about 50 micron ?bril
`length. This tape-covered wire was then heated by pulling
`the wire through the 0.14 mm diameter ori?ce of a 2.5 cm
`long die heated to 400° C., at a rate of 1.5 meters per minute,
`?rereby adhering the overlapped edges of the tape together
`and thereby adhering the tape to the wire. This wire was then
`cut into shorter lengths and spooled onto 16 bobbins. These
`bobbins were used to supply ?re wire to a model D-5600
`Steeger braider.
`A 12 meter length of 1.75 mm diameter non-porous PTFE
`mandrel was then fed into the braider Where a braided
`covering of the above wire was applied at a density of about
`16 picks/cm. An additional covering of tape cut from a sheet
`of porous expanded PTFE ?lm was ?ren helically wrapped
`over ?re surface of the wire-braided PTFE mandrel. The tape
`used for this helical wrapping was of 0.01 mm thickness, 0.3
`g/cc density, about 50 micron ?bril length and 12 mm Width.
`Adjacent edges of the helical wrapping were overlapped by
`approximately 1 mm. The wire-braided Te?on mandrel was
`then placed into an oven set at 380° C. for four minutes, after
`which it was removed and allowed to cool. As shown by
`FIG. 9, the wire-braided stent 91 with the exterior covering
`of porous expanded PTFE tape was then removed ?'om the
`non-porous PTFE mandrel 93 by folding the ends 95 of the
`braided wires back on themselves and pulling on these
`everted ends. The exterior covering of porous expanded
`PI'FE ?lm is omitted from Figure 9 for clarity. By applying
`tension on these everted ends in a direction parallel to the
`longitudinal axis of the mandrel and from the everted end
`back toward the opposite, non-everted end, the entire
`braided construction was everted and simultaneously
`removed from the mandrel. This everting process of remov
`ing the braided assembly from the mandrel resulted in the
`helical wrapping of ?lm being located on the lumen of the
`stent. This construction otfered good self-expanding char
`acteristics in that when longitudinal tension was placed on
`the stent, the length of the stent increased and the diameter
`decreased. Upon release of tension, the stent immediately
`recovered its previous shorter length and larger diameter.
`This ?lm-covered stent is therefore expected to be use?ll as
`a self-expanding stent.
`We claim:
`1. A tubular intraluminal graft comprising:
`a) a tubular diametrically adjustable stent having an
`exterior surface, a luminal surface and a wall and
`having a multiplicity of openings through the wall of
`the stent;
`b) a tubular covering of porous expanded polytetra?uo
`roethylene a?ixed to the luminal surface of the tubular,
`diametrically adjustable stent, said tubular covering
`being less than about 0.10 mm thick and said tubular
`covering having an exterior surface, a luminal surface
`and a seam extending from the exterior surface,
`through the luminal surface of the tubular covering; and
`wherein said intraluminal graft is adapted for implantation in
`a body conduit.
`2. A tubular intraluminal graft according to claim 1
`wherein the tubular covering of porous expanded polytet
`ra?uoroethylene is a?ixed to the luminal surface of ?re
`tubular diametrically adjustable stent by an adhesive.
`3. A tubular intraluminal graft according to claim 2
`wherein the adhesive is a thermoplastic adhesive.
`4. A tubular intraluminal graft according to claim 3
`wherein the thermoplastic adhesive is a thermoplastic ?uo
`ropolymer adhesive.
`
`35
`
`45
`
`55
`
`EXAMPLE4
`A long length of 0.07 mm diameter single strand 304
`stainless steel wire was provided wi?r a single layer,
`
`65
`
`W.L. Gore & Associates, Inc.
`Exhibit 1025-9
`
`

`

`5,700,285
`
`S. A tubular intraluminal graft according to claim 4
`wherein the thermoplastic ?uoropolymer adhesive is ?uori
`nated ethylene propylene.
`6.‘ A tubular intraluminal graft according to claim 1
`wherein the tubular diametrically adjustable stent is a Niti
`nol stent.
`7. A tubular intralurninal graft according to claim 1
`wherein the stent is a balloon-expandable stent.
`8. A tubular intralurninal graft according to claim 1
`wherein the stent is a self-expanding stent of braided wire.
`9. A method of making a tubular intraluminal graft
`comprising:
`a) selecting at least one tubular, diametrically adjustable
`stent having an exterior surface, a lurninal surface and
`a wall, and having a multiplicity of openings through
`the wall of the stent;
`b) a?ixing a tubular covering to the lurninal surface of the
`tubular, diametrically adjustable stent, said covering
`being less than about 0.10 mm thick and said tubular
`covering having an exterior sm'face, a lurninal surface
`and a seam extending from the exterior surface through