PCT
`
`
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`
`(51) International Patent Classification © ;
`
`
`(11) International Publication Number:
`WO 97/37713
`A61M 25/00
`
`
` (43) International! Publication Date:
`16 October 1997 (16.10.97)
`
`
`
` (81) Designated States: AL, AM, AT, AU, AZ, BA, BB, BG, BR,
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`PCT/US97/05625
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`
`
`
`(22) International Filing Date:
`3 April 1997 (03.04.97)
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`
`
`
`
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`(30) Priority Data:
`
`60/015,180
`5 April 1996 (05.04.96)
`US
`
`
`
`
`
`
`(71)(72) Applicant and Inventor: TRUCKALI, Csaba [US/US]; 627
`
`Alberta Avenue, Sunnyvale, CA 94087 (US).
`
`
` Published
`(74) Agents: HAVERSTOCK, Thomas, B. et al; Haverstock &
`Associates, Suite 420, 260 Sheridan Avenue, Palo Alto, CA
`
`
`With international search report.
`
`94306 (US).
`Before the expiration of the time limit for amending the
`
`
`claims and to be republished in the event of the receipt of
`
`amendments.
`
`(21) International Application Number:
`
`
`
`BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE,
`HU,IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS,
`LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL,
`PT, RO, RU, SD, SE, SG, SI, SK, TJ, TM, TR, TT, UA,
`UG, UZ, VN, ARIPO patent (GH, KE, LS, MW, SD, SZ,
`UG), Eurasian patent (AM, AZ, BY, KG, KZ, MD, RU,TI,
`TM), European patent (AT, BE, CH, DE, DK, ES,FI, FR,
`GB, GR, IE, IT, LU, MC, NL, PT, SE), OAPI patent (BF,
`BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE,SN, TD, TG).
`
`
`
`
`
`
`($4) Title: THIN-WALLED AND BRAID-REINFORCED CATHETER
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`
`
` ROTATIONAL
`
`COUNTER: (57) Abstract
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`A flexible catheter comprising a reinforcement sheath made of helically disposed reinforcement elements. Different elements made
`of different material and having different thickness are used in different winding directions. By braiding thicker elements in a rotational
`direction, and by braiding substantially thinner elements in a counter-rotational direction, the kink-resistance, torsional stiffness and axial
`stiffness of the resulting catheter will be increased without increasing the catheter wall thickness. Thus, the same mechanical characteristics
`of catheters having thick catheter walls can be achieved in thin-walled catheters, greatly increasing the possible lumen diameter of the
`catheters. An even thinner catheter wall can be formed when the reinforcement elements are partially embedded into the wall of the inner
`tubular member.
`
`
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`

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`ZW Slovenia
`
`.
`
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Turkmenistan
`Turkey
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`Viet Nam
`Yugoslavia
`Zimbabwe
`
`1U
`
`Z
`VN
`yU
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`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international applications under the PCT.
`SI
`Lesotho
`ES
`Albania
`SK
`Lithuania
`FI
`Armenia
`SN
`FR
`Luxembourg
`Austria
`SZ
`Latvia
`GA
`Australia
`TD
`Monaco
`GB
`Azerbaijan
`TG
`GE
`Republic of Moldova
`Bosnia and Herzegovina
`TJ
`GH
`Madagascar
`Barbados
`T™
`GN
`The former Yugoslav
`Belgium
`TR
`GR
`Burkina Faso
`Republic of Macedonia
`TT
`Mali
`HU
`Bulgaria
`UA
`IE
`Mongolia
`Benin
`UG
`Mauritania
`IL
`Brazil
`Malawi
`IS
`Belarus
`Mexico
`IT
`Canada
`JP
`Niger
`Central African Republic
`Netherlands
`KE
`Congo
`KG
`Norway
`Switzerland
`New Zealand
`KP
`Cote d'Ivoire
`Poland
`Cameroon
`Portugal
`China
`Romania
`Cuba
`Russian Federation
`Czech Republic
`Sudan
`Germany
`Sweden
`Denmark
`Singapore
`Estonia
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`LS
`LT
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`Spain
`Finland
`France
`Gabon
`United Kingdom
`Georgia
`Ghana
`Guinea
`Greece
`Hungary
`Ireland
`Israel
`Iceland
`Italy
`Japan
`Kenya
`Kyrgyzstan
`Democratic People’s
`Republic of Korea
`Republic of Korea
`Kazakstan
`Saint Lucia
`Liechtenstein
`Sri Lanka
`Liberia
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`KR
`KZ
`Lc
`ui
`LK
`LR
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`PCT/US97/05625
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`THIN-WALLED AND BRAID-REINFORCED CATHETER
`
`FIELD OF THE INVENTION
`The present invention generally relates to intravascular catheters, such as guiding
`catheters or diagnostic catheters used during percutaneous transluminal coronary
`angioplasty or microinvasive neuroradiology procedures, and any other catheters that can
`be introduced into a vasculature.
`
`BACKGROUND OF THE INVENTION
`
`With the advent of technology and surgical techniques, complicated surgical
`procedures such astransluminal coronary angioplasty and microinvasive neuroradiology
`have almost becomeroutine for cardiologists and neuro-surgeons.
`In order to perform
`these procedures, as well as others such as laser angioplasty, angioscopy or intra-coronary
`atherectomy, it is necessary to introduce a catheter into an artery of the patient, and
`subsequently advance the catheter along the course of the artery or the other blood vessels
`to engage the target tissues. Surgical or diagnostic devices are often introduced within the
`catheter.
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`‘Conventional catheters, however, have a small lumen diameter, thus limiting the
`size and complexity of the surgical or diagnostic devices that can be introduced. Those
`catheter bodies are typically made of an inner plastic tube surrounded by and reinforced
`with a braided stainless steel mesh, and covered with an outer plastic sleeve. As shown in
`Figure 1, the braided steel mesh comprises helically disposed braid elements in both
`rotational and counter-rotational winding directions. Examples of such designs are
`disclosed in U.S. Patents 3,485,234 and 3,585,707. Those catheters are often
`manufactured by extrudingaplastic tubing, and then braiding metal fibers or strands over
`25
`the plastic tubing to form a braided tube. Theplastic tubing must be sufficiently thick to
`act as a base around which the braid is woven. A second extruded layer ofplastic is then
`applied over the braided tube. Those catheters, however, while providing desirable
`mechanical characteristics, usually lack desirable wall thickness and lumen diameter.
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`surrounded by a braided reinforcing mesh andaflexible plastic outer wall is disclosed. In
`
`In order to develop catheters having a larger lumen diameter, catheter walls must
`be made as thin as possible. However, thin, under reinforced plastic tubing lacks desirable
`mechanical characteristics such as kink resistance, torsional stiffness and axialstiffness.
`An improvedtorsionalstiffness permits torque to be better transmitted from a proximal
`end ofthe catheter to a distal tip to facilitate advancement ofthe catheter through the
`branching bloodvessels of the patient. A high kink resistance is also desirable because,
`once a catheter kinks, it will lose its functionality.
`In additional, a high axial stiffness is
`desirable because an axial force is sometimes necessary to push the catheter through long
`and winding blood vessels to engage the target tissue.
`Attempts have been madeto optimize these mechanical characteristics. For
`example, in U.S. Patent 5,057,092 (Webster), a catheter comprising a flexible mner wall
`
`Webster, the braided reinforcing meshis interwoven with longitudinal wrap members
`having a low modulusofelasticity to increase axial stiffness. Such a braided reinforcing
`mesh can increase torque and or axial stiffness of the catheter. However, a major
`drawback of such a design is that as more reinforcing elements are involved, catheter wall
`thickness is necessarily increased, thus reducing the lumen diameter. Furthermore, that
`mesh design does not enhance the torque performance or pushability of the catheter, since
`identical braid members are used in both winding directions.
`Other examples include U.S. Patents 5,176,660 and 5,019,057, both authored by the
`applicant herein.
`In those patents, the applicant discloses a flexible catheter comprising a
`resilient, tubular layer in telescopic relation with a tubular sheath made ofhelically
`disposed strands.
`In that design, at least one of the helically disposed strands that are
`comprised of the tubular sheath is flat and has a width that substantially exceeds its height.
`Furthermore, to increase axial stiffness, the catheter also requires at least one axial
`reinforcing element. However, although such a braid reinforcement element can enhance
`torque response and axialstiffness of the catheter, that design does not reduce the wall
`thickness. Furthermore, it is important to note that the braided structure disclosed in these
`two patents comprises a plurality offlat and round elements that are wound in both
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`rotational and counter-rotational directions. Because ofthis disposition of braid elements,
`such a design does not increase the torque response and pushability of the catheter.
`Attempts have also been madeto reduce wall thickness of prior art devices by
`reducing the thickness of the reinforcing elements and increasing their tensile strength.
`However, decreasing the diameter of the reinforcing elements will also decrease the kink
`resistance of the catheter.
`
`The relationship between the kink-resistance of a catheter and the diameter of the
`reinforcing elements can be described in the formula below:
`
`For a round reinforcing element:
`
`Lound= D* x 7 / 64
`whereDis the diameter of a round reinforcing element, and Touna 18 the kink resistance of
`the braided reinforcing sheath. And, for a rectangular reinforcing element:
`Jrectanguas= A’ X B/ 12
`where A andBare the dimensionsofa rectangular reinforcing element.
`Thus, decreasing the diameter or cross-sectional area of the reinforcing elements
`15
`will reduce the kink resistance of the catheter. The increased tensile strength cannot
`compensate for the reduced kink-resistance of these constructions, and therefore, when
`sharply bent, a catheter constructed with thin reinforcing elements only will become
`excentric (collapse), reducing its torque performance. The catheter may also kink and lose
`its functionality.
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`20
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`Other prior art devices attempted to reinforce the catheter with coil-like structures.
`However,coils tend to have good torque transmission only in one direction (in the
`winding direction). A rotational force applied opposite to the coil’s winding direction
`tends to open thecoil structure, and therefore, the rotational force is not transmitted. Coil
`structures do not provide sufficient torque transmission capability because the reinforcing
`membersare not interlaced with other reinforcing members. As a result, if a torque is
`applied to a proximal endofthe coil structure, the coil will increase or decreaseits
`nominal diameter depending on the direction ofthe torque, rather than transmitting the
`torque to a distal end.
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`None of the prior art devices above has a high torsional stiffness, a high axial
`stiffness and a high kink resistance without sacrificing wall thickness. What is needed is a
`flexible catheter having the largest possible lumen diameter without losing torsional
`
`stiffness, axial stiffness, and kink resistance.
`
`SUMMARY OF THE INVENTION
`
`An object of the present invention is to provide a reinforcement structure for and a
`method of constructing a catheter with minimum wall thickness and maximum axial
`
`stiffness, torsional stiffness, and kink-resistance.
`In the preferred embodimentofthe invention, a flexible catheter comprisesat least
`one tubular member which is surrounded by a tubular sheath made ofhelically disposed
`crossing strands. The novelty in this invention is the use of braid elements having
`different thicknesses and/or different elasticities in different winding directions. By
`braiding thicker, higher bending modulus elements in a rotational direction, and by
`braiding substantially thinner, higher elastic modulus elementsin a counter-rotational
`direction, the torsional and axial stiffness of the resulting catheter will be increased
`without increasing the catheter wall thickness. Thus, the same mechanical characteristics
`of catheters having thick catheter wall can be achieved in thinner walled catheters, greatly
`increasing the possible lumen diameter ofthe catheters. Kinkresistance is also increased
`because, by interweaving smaller diameter elements with larger diameter elements, the
`larger elements are able to maintain a near-perfect helical shape, thus increasing the radial
`strength and kink resistance of the catheter. The high clastic modulusof the thinner
`elements keep the thicker elements in place to ensure uniform torque performancein both
`
`rotational and counter-rotational directions.
`To further reduce the wall thickness, a catheter can be made such that some of the
`braid elements are partially embedded into the wall of the inner tubular member. Such a
`catheter can be manufactured by first applying a thin inner tubular memberover a
`stretchable mandrel. Braid elements are then woundtightly around the thin inner tubular
`member to form a braided-tube/mandrel assembly. After an outer tubular memberis
`applied over the braided-tube/mandrel assembly, a tension is applied to the mandrel such
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`that it is straightened. The braided tube and the outer tubular member are then fused
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`together. The assembly is then cooled and the mandrel is stretched to a point such that its
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`diameter is reduced. The constricted mandrel can then be readily removed and discarded.
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`By using a stretchable mandrel, a thin walled inner tubular membercan be used in spite of
`the inward pressure resulting from the tight braiding. The step of stretching the mandrel,
`and thus reducing its diameter, allows the mandrel to be easily removed. This process also
`allows non-extrudable materials such as PTFE to be used for forming the inner tubular
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`member.
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`Figure |
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`illustrates a prior art catheter reinforced with symmetrically disposed braid
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`elements in both winding direction.
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`Figure 2 illustrates a partial cut-away view of the preferred embodiment of the
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`present invention.
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`15
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`Figure 3 illustrates a cross-sectional. view of the preferred embodiment of the
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`present invention.
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`Figure 4 illustrates the steps necessary for manufacturing the present invention.
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`Figure 5 illustrates an alternate embodiment of the present invention where the
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`braid elements are not partially embedded into the wall of the inner tubular member.
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`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
`
`Figure 2 showsa telescopic view of the reinforced catheter in accordance with the
`
`present invention. A braided structure 204 is formed over an inner tubular member 202,
`and is encapsulated by an outer tubular member 206 to form a composite catheter body
`200. All large diameter elements 212 of the braided reinforcement structure 204 are
`
`wound helically in a same rotational direction. All small diameter elements 214 of the
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`braided structure 204 are interwoven with the large diameter elements 212 and are wound
`in a counter-rotational direction. The small diameter elements 214 and the large diameter
`elements 212 can be braided using methods known in theprior art. The large diameter
`elements 212 are preferably made of metallic materials such as stainless steel, nitanol
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`alloy, copper or any other material suitable for braiding. The material would preferably
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`have a high bending stiffness. Other materials such as carbon or fused silica fibers can
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`also be used.
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`It is not required that all the large diameter elements 212 are uniformly made of
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`one material. Depending on the intended application of the catheter and the desired
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`mechanical characteristics, different combinations of large diameter elements 212 made of
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`different materials may be used. Furthermore, it is not required that all large diameter
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`elements have an identical diameter or cross-sectional area. Again, depending on the
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`application of the catheter and the materials used, the large diameter elements 212 may
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`comprise filaments of different diameters, as long as they are substantially thicker than the
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`small diameter elements 214.
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`All small diameter elements 214 are wound helically in the counter-rotational
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`direction and are interlaced with the large diameter elements to form the braided structure
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`204. The small diameter elements 214 are made of preferably high tensile strength
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`15
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`materials, such as high tensile strength stainless steel, kevlar or any other metallic or non-
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`metal suitable for braiding.
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`It is not necessary that all the small diameter elements are
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`made of a single material. Depending on the application of the catheter and the desired
`mechanical characteristics, the small diameter elements 214 may comprise a multitude of
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`materials. Furthermore, the small diameter elements 214 may also comprise filaments of
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`different diameters, as long as they are substantially thinner than the large diameter
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`elements 212.
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`In this construction, the larger diameter elements with a bending stiffness are
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`responsible for the maintaining the high kink resistance of the catheter. However, without
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`the high tensile strength small diameter elements locking the large elements in place, the
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`25
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`large diameter elements will have poor torque performance when a counter-rotational force
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`is applied. As discussed above, coils tend to have good torque transmission only in one
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`direction (in the winding direction).
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`In order to provide good torque performance and
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`kink resistance, small diameter elements with high tensile strength are wound in the
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`counter-rotational direction to keep the large diameter elements in place, assuring uniform
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`torque performance in both rotational and counter-rotational directions.
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`Figure 3 is a cross-sectional view of the preferred embodimentofthe present
`invention. To further reduce catheter wall thickness, the braid elements 312 and 314 could
`be embeddedat least partially into the wall of the inner tubular member 302.
`It is understood that the present invention is not intended to be limited by a cross-
`sectional shape of the braid elements. Thefigures, showing braid elements having a round
`cross-sectional shape, are intended forillustration purposes only.
`It is understood that
`braid elements having different cross-sectional shapes can also be used, and that they are
`also intended to be covered bythis patent. Furthermore, it is also understood that round
`braid elements should have an oblong cross-sectional shape because the cross-section is
`madeat an angle to the braid element. However, for the sake of simplicity, the cross-
`section of the braid elements are shown to be round.
`In addition, it is understood that the
`diagramsillustrate 8 large diameter elements interwoven with 8 smal! diameter elements
`for illustration purposes only. The number of large diameter elements and the number of
`small diameter elements do not have to be the same, and the numberis not limited to 8.
`It should also be understoodthat large diameter elements have a larger bending stiffness
`than the small diameter elements.
`
`Figures 4a-c illustrate the steps which are necessary for the manufacture of the
`preferred embodimentofthe present invention. According to Figure 4a, an inner tubular
`member 402 made of PTFE is placed over an annealedstretchable copper mandrel 401
`(or other suitable mandrel such as an annealedstainless steel mandrel) in such a way that
`both ends of the mandrel 401 extend out from the inner tubular member 402. Preferably,
`the inner tubular member 402 has been chemically etched for enhanced braiding
`capabilities. The mandrel 401 has a diameter approximately the same as an inside
`diameter of the inner tubular member 402. This assembly is fed into a braiding machine
`where braid elements 412 and 414 are braided tightly around the inner tubular member
`402. Preferably, the braiding can be sufficiently tight that someof the braid elements 412
`and 414 are partially embedded into the inner tubular member 402 to form a braided
`assembly 420, as shown in Figure 4b. After the braiding operation, an outer tubular
`member 406is placed over the braided assembly 420 suchthat the outer tubular mandrel
`406 covers at least partially the inner tubular member 402, as shown in Figure 4c. The
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`outer tubular member 406 can be constructed from thermoplastic elastomer such as nylons,
`urethane, or other suitable materials. After the outer tubular member 406 is placed, a heat
`shrinkable tubing (such as FEP) is placed over the outer tubular member 406.
`Because the mandrel 401 is made of a stretchable material, the mandrel 401 is
`
`malleable and by this time would be bentin several directions from handling during the
`braiding and tube assembly processes.
`If fusing occurs when the mandrelis bent, the
`resulting catheter will also be crooked. Therefore, it is necessary to straighten the mandrel
`401 before the final fusing process takes place. A straightening force can be applied in a
`fusing machine to straighten the mandrel 401. However,the straightening force should be
`small enough to prevent stretching the mandrel 40] to the point that would reduce its
`diameter more than 0.001". A heat process can be used to shrink the heat shrinkable
`tubing, melting and fusing the inner and outer tubular members together to a form a
`cohesive composite structure. After the fusing process and after the catheter is cooled to
`an ambient temperature, a second stretching force is applied to the mandrel 401 to reduce
`its diameter so that it can be removed from the assembly. The heat shrunk tube can be
`removed by simply cutting it away. This process allows very thin materials such as PTFE
`to be made into the inner tubular member 402. This is because the mandrel 401 provides
`sufficient structure to support the braiding operation. Ordinarily, the pressure between the
`catheter structure and the mandrel would prevent ready removal of the mandrel. However,
`in here, because a stretchable mandrel is used the catheter can be formed with the thin
`walled tubular members 402.
`Construction of the braided reinforcement sheath, however,is not limited to this
`manufacturing method. A continuous extrusion process can also be used. Using this
`method, a plastic inner tubular member is continuously extruded over a stretchable
`mandrel wire. Then, reinforcing elements are braided over the plastic inner tubular
`member to form a braided assembly. The braided assembly is fed through a second
`extrusion machine where an outer tubular memberis extruded over and fused with the
`braided assembly to form a composite structure. The stretchable mandrel can be stretched
`to a reduce its diameter such that the mandrel can be removed from the catheter lumen.
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`Figure 5 showsthe cross-sectional view of an alternate embodimentofthe present
`invention where reinforcing elements 512 and 514 are embedded into an outer tubular
`member 506, but are not embedded into an inner tubular member 502. The catheter in
`this case can be built in the following steps. A braided sheath is formed in a separate
`mandrel and is then transferred over an inner tubular member-metal mandrel assembly
`with very low tension on the individual braiding elements to prevent the braid to lock on
`to the stainless steel mandrel. An outer tubular member 506at this point can be placed
`over the braid-inner tubular member-mandrel assembly. The outer tubular member 506
`will then be fused together with the inner tubular member-braided sheath-mandrel
`assembly with the help of a heated die or with the aid of a suitable heat shrinkable tubing.
`The heat shrinkable tubing can be removed after the fusing process (can be cut away too),
`and thestainless steel mandrel can be removed by pulling it out from the composite
`tubular structure.
`
`Many long-feit needs in the field of catheters have been fulfilled by the present
`invention. A catheter made accordingto the present invention by interlacing thick
`braiding elements in one direction with thin braiding elements in an opposite direction
`allows thinner walled catheters to be made. Desirable mechanical characteristics such as
`torsional stiffness, axial stiffness and kink resistance can now be achieved without
`sacrificing wall thickness. Furthermore, by braiding the braid elements overa stretchable
`mandrel, wall thickness is further decreased because the braid elements can be partially
`embedded into the inner tubular wall of the catheter. Thin, non-extrudable materials such
`as PTFE may now be used to form the inner tubular member.
`Thepresent invention has been described in terms of specific embodiments
`incorporating details to facilitate the understanding of the principles of construction and
`operation of the invention. Such reference herein to specific embodiments and details
`thereof is not intended to limit the scope of the claims appended hereto.
`It will be
`apparent to those skilled in the art that modifications may be made in the embodiment
`chosenfor illustration without departing from the spirit and scope of the invention.
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`CLAIMS
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`Whatis claimedis:
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`I
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`2
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`3
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`4
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`5
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`6
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`7
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`l
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`2
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`1
`2
`3
`4
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`1
`2
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`3
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`1
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`2
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`1
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`2
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`1.
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`A catheter for insertion into a human vasculature, comprising:
`
`a.
`
`b.
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`a first tubular member; and
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`a braided reinforcing sheath in concentric relation to the first tubular
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`member, the reinforcing sheath comprising a first strand interlaced with a
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`second strand, wherein the first strand is helically disposed in an opposite
`
`winding direction to the second strand, wherein the first strand is
`
`substantially thicker than the second strand.
`
`2.
`
`The catheter according to claim 1, further comprising a second tubular
`
`member in concentric relation to and surrounding the braided reinforcing sheath.
`
`The catheter according to claim 1, wherein the reinforcing sheath further
`3.
`comprises a plurality of first strands interlaced with a plurality of second strands, each of
`the first strands being helically disposed in a rotational winding direction, each of the
`second strands being helically disposed in a counter-rotational winding direction.
`
`The catheter according to claim 3, wherein each of the plurality of first
`4.
`strands is made ofa first material and each of the plurality of second strands is made of a
`
`second material.
`
`5.
`
`The catheter according to claim 4, wherein the first material has a higher
`
`bending stiffness than the second material.
`
`6.
`
`The catheter according to claim 4, wherein the first material is metallic and
`
`the second material is non-metallic.
`
`Page 12
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`Medtronic Exhibit 1047
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`Page 12
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`Medtronic Exhibit 1047
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`

`

`WO 97/37713
`
`PCT/US97/05625
`
`1
`
`2
`3
`4
`
`1
`2
`
`1
`2
`
`3
`4
`5
`6
`7
`8
`9
`10
`
`1
`
`2
`
`l
`2
`3
`
`J
`2
`wo
`
`7.
`
`The catheter according to claim 1, wherein the first strand is made of a first
`
`material and the second strand is made of a second material, wherein the first material and
`the second material have high elastic modula, further wherein the first material having a
`higher bending stiffness than that of the second material.
`
`The catheter according to claim 1, wherein the braided reinforcing sheath is
`8.
`partially embedded into a wall of the inner tubular member.
`
`A flexible, thin-walled and kink-resistant catheter for insertion into a human
`9,
`vasculature, comprising:
`
`b.
`
`c.
`
`an inner tubular member made of PTFE;
`a first plurality of strands helically interlacing in opposite winding directions
`to a second plurality of strands to form a braided sheath, the first strands
`and the second strands both being wound onto the inner tubular member,
`wherein eachofthe first strands is substantially thicker than each of the
`second strands; and
`an outer tubular member formed by fusing a second thermoplastic material
`over the braided reinforcing sheath.
`
`10.
`
`The catheter according to claim 9, wherein the PTFE is formed over a
`
`stretchable mandrel.
`
`The catheter according to claim 9, wherein the inner tubular member, the
`11.
`braided reinforcing sheath, and the outer tubular member are fused together to form a
`composite structure.
`
`The catheter according to claim 9, wherein thefirst strands are made of a
`12.
`first material and the second strands are made of a second material, wherein the first
`material has a higher bending stiffness than the second material.
`
`11
`
`Page 13
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`Medtronic Exhibit 1047
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`WO 97/37713
`
`PCT/US97/05625
`
`1
`
`2
`
`—
`
`OoOoJNDNWNF&FWYLY
`
`— >
`
`— —
`
`— nN
`
`— w
`
`— >»
`
`15
`
`]
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`8
`
`9
`
`10
`
`13.
`
`The catheter according to claim 12, wherein the first material and the
`
`second material have high elastic modula.
`
`14.
`
`A flexible, thin-walled and kink-resistant catheter for insertion into a human
`
`vasculature, comprising:
`
`a.
`
`b.
`
`an inner tubular member made of PTFE;
`
`a braided reinforcing sheath in concentric relation with the inner tubular
`
`member, the reinforcing sheath comprising a plurality offirst strands
`
`helically interlaced with a plurality of second strands, each ofthe first
`
`strands being helically disposed in a first winding direction, each of the
`
`second strands being helically disposed in a second winding direction, each
`
`of the first strands being substantially thicker than each of the second
`
`strands, each of the first strands being made ofa first material and each of
`
`the second strands being made of a second material, wherein thefirst
`
`material and the second material have a high elastic modulus, further
`
`wherein the first material has a higher bending stiffness than the second
`
`material; and
`
`Cc.
`
`an outer tubular member.
`
`15.
`
`A method of manufacturing a catheter for insertion into a human
`
`vasculature, comprising the steps of:
`
`a.
`
`placing a first tubular member over a stretchable mandrel, the stretchable
`
`mandrel having two ends, such that both ends of the stretchable mandrel
`
`extend out from the first tubular member, wherein the first tubular member
`
`is made of PTFE:
`
`b.
`
`braiding reinforcement filaments over the first tubular member to form a
`
`reinforcing mesh, the filaments being partially embedded into the first
`
`tubular member;
`
`c.
`
`placing a second tubular member over the reinforcement mesh;
`
`Page 14
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`Medtronic Exhibit 1047
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`

`

`WO 97/37713
`
`PCT/US97/05625
`
`11
`12
`13
`14
`
`1
`2
`3
`
`1
`2
`3
`4
`5
`
`1
`2
`
`1
`2
`3
`
`d.
`
`€.
`
`fusing the second tubular memberto the reinforcementfilaments and the
`first tubular member; and
`removing the mandrel by stretching the stretchable mandrel to reduce a
`diameter of the stretchable mandrel.
`°
`
`The method according to claim 15, further comprising the step of applying
`16.
`a tension to both ends of the stretchable mandrel to straighten the stretchable mandrel and
`the first tubular memberprior to the step of fusing.
`
`The method according to claim 15, wherein the reinforcementfilaments
`17.
`comprise a plurality of first strands helically interlaced with a plurality of second strands,
`each one ofthe first strands being helically disposed in a first winding direction, each one
`of the secondstrandsbeinghelically disposed in a second windingdirection, further
`wherein each of the first strands is substantially thicker than each of the second strands.
`
`The method according to claim 17, wherein each ofthe first strands is made
`18.
`of a first material, wherein each of the secondstrands is made of a second material.
`
`The method according to claim 15, further comprising the step of cooling a
`19.
`fused assembly comprising the mandrel, the inner tubular member, the braided sheath, and
`the outer tubular memberprior to the step of removing.
`
`13
`
`Page 15
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`WO 97/37713
`
`PCT/US97/035625
`
`I
`
`2
`
`3
`
`4
`
`5
`
`20.
`
`A method of forming a catheter, comprising:
`
`a.
`
`b.
`
`applying the tubular layer of PTFE to a stretchable mandrel, the stretchable
`
`mandrel having two ends;
`
`braiding reinforcement filaments over the tubular layer of PTFE to form a
`
`reinforcing mesh, the filaments being partially embedded into the tubular
`
`6
`layer of PTFE;
`
`7 applyingafirst tension to the stretchable mandrel by pulling the two endsc,
`
`
`
`8
`9
`10
`
`li
`
`12
`13
`14
`
`15
`
`16
`
`for straightening the stretchable mandrel;
`applying