United States Patent (19)
`Berg et al.
`
`54). GUIDE CATHETER HAVING SELECTED
`FLEXURAL MODULUS SEGMENTS
`75 Inventors: Todd A. Berg, Lino Lakes; Jason A.
`Galdonik, Bloomington, both of Minn.
`(73) Assignee: SciMedLife Systems, Inc., Maple
`Grove, Minn.
`This patent is subject to a terminal dis-
`claimer.
`
`Notice:
`
`*
`
`21 Appl. No.: 08/800,927
`22 Filed:
`Feb. 13, 1997
`O
`O
`Related U.S. Application Data
`63 Continuation-in-part of application No. 08/703,635, Aug.
`27, 1996, which is a continuation-in-part of application No.
`08/195.222, Feb. 14, 1994, Pat. No. 5,569.218.
`1) Int. Cl." ................................................. A61M 25/00
`2) U.S. Cl. ........................... 604/525; 604/527; 138/125
`8 Field of Search ..................................... 604/264, 280,
`604/281, 282; 600/433-435; 138/130-132,
`125, 129, 144
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`3,416,531 12/1968 Edwards.
`3,485,234 12/1969 Stevens.
`4,385,635 5/1983 Ruiz.
`4,563,181
`1/1986 Wijayarathna et al. ................ 604/280
`4,636,346
`1/1987 Gold et al..
`4,690,175 9/1987 Ouchi et al..
`4,735,620 4/1988 Ruiz ........................................ 604/281
`4,838,879 6/1989 Tanabe et al. ...
`... 604/28O
`4,863,442 9/1989 DeMello et al...
`... 604/282
`4,899,787 2/1990 Ouchi et al. ............................ 604/282
`
`
`
`USOO591.1715A
`Patent Number:
`11
`(45) Date of Patent:
`
`5,911,715
`*Jun. 15, 1999
`
`5,176,660 1/1993 Truckai ................................... 604/282
`5,221,270 6/1993 Parker ......
`... 604/282
`5,222,949 6/1993 Kaldany ..........
`... 604/282
`Stig SE Malay et al. ...................... S5
`21- 2
`OlleSZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
`5,279.596
`1/1994 Castaneda et al. .
`604/282
`s: to set along:
`5,445,624 8/1995 Jimenez ...
`... 604/264
`5,545,151
`8/1996 O'Connor et al.
`604/282
`5,569,218 10/1996 Berg ................
`... 604/264
`5,658.263 8/1997 Dang et al.
`604/282
`5,676,659 10/1997 McGurk .................................. 604/282
`FOREIGN PATENT DOCUMENTS
`0 180 348 5/1986 European Pat. Off..
`O 555 088 8/1993 European Pat. Off..
`92/15356 9/1992 WIPO.
`9215356 9/1992 WIPO.
`Primary Examiner Ronald Stright, Jr.
`Attorney, Agent, or Firm-Crompton, Seager & Tufte, LLC
`57
`ABSTRACT
`Aguiding catheter for use in coronary angioplasty and other
`cardiovascular interventions which incorporates a plurality
`of segment of selected flexural modulus in the shaft of the
`device. The segments which have a different flexibility than
`the Sections immediately proximal and distal to them, cre
`ating Zones in the catheter shaft which are either more or leSS
`flexible than other Zones of the shaft. The flexibility and
`length of the shaft in a given Zone is then matched to its
`clinical function and role. A mid-shaft Zone is significantly
`Softer than a proximal shaft or distal Secondary curve to
`better traverse the aortic arch shape without Storing too
`much energy. A Secondary Zone Section is designed to have
`maximum Stiffness to provide optimum backup Support and
`stability.
`
`26 Claims, 15 Drawing Sheets
`
`xxx xxxx 222222222Nr.
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`Sheet 10 0f 15
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`U.S. Patent
`US. Patent
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`Jun. 15, 1999
`Jun. 15 1999
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`5,911,715
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`Jun. 15, 1999
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`5,911,715
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`1
`GUIDE CATHETER HAVING SELECTED
`FLEXURAL MODULUS SEGMENTS
`
`CROSS-REFERENCES TO CO.-PENDING
`APPLICATIONS
`This application is a continuation-in-part of U.S. patent
`application Ser. No. 08/703,635, filed Aug. 27, 1996,
`entitled “Guide Catheter Having a Plurality of Filled Distal
`Grooves', which is a continuation-in-part of U.S. patent
`application Ser. No. 08/195.222, filed Feb. 14, 1994, entitled
`"Elastic Guide Catheter Transition Element” now issued as
`U.S. Pat. No. 5,569,218, both to the same assignee.
`
`TECHNICAL FIELD
`The present invention generally relates to the field of
`intravascular medical devices, and more Specifically refers
`to the field of catheterS Such as guiding catheters used for the
`placement of medical devices and diagnostic catheters used
`to inject radiopaque fluids within the body for treatment and
`diagnosis of vascular diseases. In particular, the present
`invention relates to an improved guide or diagnostic catheter
`of a braided or braidleSS catheter design, having a transition
`Zone with a different flexibility than adjacent portions of the
`catheter Shaft for improved catheter performance.
`
`15
`
`25
`
`BACKGROUND OF THE INVENTION
`
`2
`to have the distal end more flexible to allow for better
`placement of the guide catheter. Having the distal Section
`more flexible also creates a leSS traumatic Section to the
`blood vessel. The distal end of the catheter is rotated,
`through the transmission of torque from the proximal end,
`until the tip of the guiding catheter is in the desired position.
`With the variations of different bend shapes available on the
`distal ends of these devices and with variations in patient
`anatomy, each device may need to be torqued more or leSS
`in order to correctly place it.
`One problem that has surfaced is that as more flexible
`distal Sections are placed on these catheters, the incidence of
`guide catheter back-out is increased. Guide catheter back
`out occurs when the guide disengages from its preferred
`positioning (e.g., coronary ostium), thereby creating the
`need for the physician to reposition the guiding catheter.
`Many different guide catheter curve shapes have been
`designed to overcome this problem, with each giving dif
`ferent levels of Support. However, as the flexibility of the
`distal most Section is increased, the tendency for back-out
`again increases.
`It is possible to construct a device that is very rigid to
`obtain the correct amount of back-out Support. However, the
`resulting device would be very traumatic to the patient's
`arteries due to its rigidity. Similarly, it is possible to con
`struct a very flexible device to limit the trauma the device
`imparts to the blood vessels. However, the device then
`becomes too flexible and does not provide any back-out
`Support.
`Another problem that is seen in current devices is that
`devices are constructed Such that they are equally flexible in
`all planes. That feature is not always desired.
`SUMMARY OF THE INVENTION
`The present invention overcomes the disadvantages asso
`ciated with the prior art by providing a transition element in
`the material. The present invention allows for flexibility of
`a guiding catheter to be increased, while maintaining its
`ability to prevent guide catheter back-out. The present
`invention also allows for the rigidity of a guiding catheter to
`be increased in a discrete Segment, thereby increasing the
`back-out resistance while maintaining the flexibility. The
`present invention provides a manner in which a device of
`varying flexibility may be made very inexpensively. The
`present invention also provides a manner in which differ
`ential flexibility may be imparted to a guide catheter.
`A preferred embodiment of the present invention includes
`a tubular member for a guide catheter and a guide catheter
`which incorporates an inner tubular member, a wire braid
`disposed over at least a portion of the inner tubular member
`and a plurality of discrete Segments of outer tubular member
`overlying the braid and inner tubular member. The discrete
`segments of outer tubular member are of selected flexibility
`or durometer to selectively vary the flexural modulus of the
`catheter tube or guide catheter distal region to match iden
`tified functions of the particular Segment of the catheter Shaft
`in Specific intravascular procedures. Unlike prior art
`catheters, this preferred design incorporating distinct
`Segments, does not necessarily follow the current Standard
`of each Section of a catheter becoming more flexible as you
`move proximal to distal along a catheter shaft. Thus, each
`discrete Segment of the catheter Shaft of the present embodi
`ment is matched to its clinical role and function. Each
`Section has a specific flexural modulus, length and location
`along the catheter tube or guide catheter.
`In a preferred embodiment of a catheter incorporating
`discrete Segments of varying flexibility, the catheter shaft
`
`35
`
`40
`
`The use of intravascular catheters for the treatment of
`cardiovascular disease is well known in the field of medi
`cine. The need for a greater variety of devices to treat
`different types of circumstances has grown tremendously as
`the techniques for the use of Such devices has progressed.
`Prior art guiding catheters are generally comprised of a
`shaft which is hollow, defining an inner lumen. The shaft is
`generally comprised of two tubes congruent to each other
`with a Support member therebetween. A hub is connected to
`the proximal end of the shaft to provide a means for
`connecting another device Such as a Syringe to inject fluids,
`or for providing a means to direct the device in order to place
`it within the vessel. A tip of a desired shape is provided at
`the distal end of the shaft.
`An example of a prior art guide catheter as described
`above is located in PCT publication No. WO 92/15356,
`published Sep. 17, 1992, to Nita et al., for CARDIOVAS
`45
`CULAR CATHETER HAVING DISCRETE REGIONS OF
`VARYING FLEXIBILITY, which teaches a guide catheter
`that has varying flexibilities along its length.
`In order for the physician to place the catheter at the
`correct location in the vessel, the physician must apply
`longitudinal and rotational forces. In order for the catheter to
`transmit these forces from the proximal end to the distal end,
`the catheter must be rigid enough to push through the blood
`vessel, but yet flexible enough to navigate the bends in the
`blood vessel. The catheter must also be torsionally rigid to
`transmit the applied torque. To accomplish this balance
`between longitudinal rigidity, torsional rigidity, and
`flexibility, there is often a support member added to the
`shaft. This Support member is often comprised of a metal
`braid or coil embedded in the shaft. This support wire is
`often embedded in the shaft between the two layers of tubing
`that comprise the Shaft.
`A guiding catheter is guided through the aorta over the
`aortic arch and down to the ostium of the vessel which is to
`be treated. It is preferable to have a soft tip or flexible section
`engage the ostium. Therefore, it is advantageous to have the
`proximal Section be rigid to transmit the forces applied, but
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`includes at least two, but preferably Six Zones of controlled
`flexural modulus due to the discrete Segments of outer
`tubular member thereon. These include a proximal shaft
`Zone of flexural modulus greater than 49 Kipsi, a mid-shaft
`Zone of flexural modulus from 29-67 Kipsi, a secondary
`curve Zone of flexural modulus greater than 49 Kipsi, a
`transition Zone of flexural modulus from 13-49 Kipsi, a distal
`section Zone of flexural modulus from 2-49 Kipsi, and a soft
`tip Zone of flexural modulus between 1 and 15 Kipsi. A
`preferred embodiment can also include a very short distal
`bumper Zone of flexural modulus of less than 7 Kipsi. These
`Zones are preferably created by utilizing a discrete Segment
`of outer tubular member manufactured from a polyether
`block amide having a Selected StiffneSS or durometer rating
`to achieve the desired flexural modulus of the shaft when the
`discrete outer tubular Segment functions in combination with
`the inner tubular member and braid if disposed thereunder.
`In another preferred embodiment of the invention, the
`catheter Shaft material is removed in the transition Section.
`The outer tube of the shaft is removed down to the braid of
`the catheter. This is done by a grinding process. The removal
`of this material creates a band in which there is no material
`present. That band is then filled with a material having
`different physical properties than the material which was
`removed, thereby changing that Section's properties.
`If the filler material Substituted in the band is a more
`flexible material, the transition section will have the flex
`ibility of both the remaining inner tube layer, the braid, and
`the new outer material. It is clearly seen that while this
`catheter Section becomes a new combination, it will Still be
`more flexible than the Sections immediately proximal and
`distal to it. If the filler material Substituted in the band is a
`more rigid material, the combination of the materials in this
`transition Section will be more rigid than the Sections
`immediately proximal and distal to it.
`In another embodiment of the present invention, a tran
`Sition Zone is formed by removing catheter shaft material
`from the catheter shaft distal portion, forming one or more
`annular grooves, and further forming one or more longitu
`dinal grooves contiguous with the annular grooves and
`contiguous with the shaft distal end. Softer, more flexible
`material Suitable for forming an atraumatic tip is used as the
`filler material. The soft filler material extends distally,
`extending past the transition Zone and forming the atrau
`matic tip itself. In this manner, the transition Zone and tip are
`formed of the same material and in the same Step.
`Another embodiment of the present invention includes an
`improved intravascular catheter for use in catheter proce
`dures. The catheter includes a shaft having a proximal end,
`a distal end, and a lumen extending longitudinally there
`through. The catheter shaft includes a first layer and a Second
`layer overlying the first layer. The improvement includes a
`transition Zone located along the catheter Shaft having a
`different degree of flexibility than an adjacent portion of the
`shaft. The transition Zone includes a high density of grooves.
`The grooves may be generally annular grooves. The
`grooves may include micro-grooves. In one embodiment,
`the annular grooves have a density greater than 5 grooves
`per inch, with preferably 5 to 50 grooves per inch.
`The grooves may be located within the second layer. The
`grooves may be generally annular, but extending less than
`360 degrees about the catheter shaft to form a bending
`plane.
`The transition Zone may be located proximal of the distal
`end. The catheter shaft may be curved, and the transition
`Zone may be located along the curve of the shaft. The
`
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`catheter shaft may include a primary curve, wherein the
`transition Section is located along the primary curve.
`The catheter may further include a Support layer overlying
`the first layer. The grooves may be located within the second
`layer and not extend down to the Support layer.
`The catheter may further include material located within
`the grooves, having a different shore hardneSS than the
`second layer. The material may be relatively softer than the
`Second layer. Alternatively, the material may be relatively
`stiffer than the second layer.
`In another embodiment, the present invention is an intra
`vascular catheter for use in catheter procedures. The catheter
`includes a shaft having a proximal end, a distal end, and a
`lumen extending longitudinally therethrough. The shaft
`includes a first layer with a Second layer overlying the first
`layer.
`The catheter shaft includes a first curve. The improvement
`includes a transition Zone located along the catheter Shaft
`first curve having a different degree of flexibility than an
`adjacent portion of the shaft. The second layer within the
`transition Zone has a high density of Surface contours located
`therein.
`The Surface contours may be micro-contours. The Surface
`contours may include a plurality of generally annular
`grooves. The catheter may further include material located
`within the Surface contours having a different Shore hardneSS
`relative to the second layer. The material may be softer
`relative to the Second layer. Alternatively, the material may
`be stiffer relative to the second layer.
`The catheter may include a Second curve along its Shaft,
`and a Second transition Zone may be located along the
`Second curve. The catheter may further include material
`located within the Surface contours of the Second transition
`Zone, having a different Shore hardneSS relative to the Second
`layer. The catheter may further include material located
`within the Surface contours of the transition Zone located
`along the first curve, having a greater Shore hardness rating
`relative to the material located within the Second transition
`Zone located along the Second curve.
`The present invention includes a method of manufactur
`ing a catheter for use in intravascular catheter procedures.
`The method includes providing a mandrel and forming a first
`layer over the mandrel. A Second layer is overlayed or
`coupled to the first layer. A portion of the Second layer is
`removed to form a high density of grooves in the Surface of
`the Second layer.
`The portion of the Second layer may be removed using an
`abrasion process. The grooves may be generally annular
`grooves. The abrasion proceSS may further include the Steps
`of rotating the catheter about its longitudinal axis. Agrinding
`wheel having a pattern corresponding to the generally annu
`lar grooves is rotated. The catheter is moved into the
`grinding wheel to a desired depth. The grooves may be
`V-shaped.
`The grooves may be micro-grooves. The density of the
`grooves may be greater than 5 grooves per inch, with 5 to 50
`grooves per inch preferred. The grooves may be filled with
`a material having a different hardneSS rating relative to the
`second layer. The material may be softer relative to the
`Second layer. Alternatively, the material may be harder
`relative to the second layer. The method may further include
`the Step of grinding the catheter to a uniform outside
`diameter.
`BRIEF DESCRIPTION OF THE DRAWINGS
`The invention will be further described with reference to
`the accompanying drawings where like numbers refer to like
`parts in Several views and wherein:
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`FIG. 1 is a plan view showing a section of the catheter
`shaft;
`FIG. 2 is another plan view of the catheter shaft with a
`length of the shaft ground down to create a band;
`FIG. 3 is a plan view of FIG. 2 after the filler material has
`been added;
`FIG. 4 is a perspective view of the catheter shaft of FIG.
`3;
`FIG. 5 is one embodiment of the present invention;
`FIG. 6 is a cross section of FIG. 3 along line 6-6;
`FIG. 7 is another embodiment of the present invention;
`FIG. 8 is a cross section of FIG. 7 along line 8-8;
`FIG. 9 is a plan view of another embodiment of the
`present invention, including a transition Zone located along
`the catheter shaft;
`FIG. 10 is a partial enlarged perspective view showing the
`transition Zone along the catheter Shaft;
`FIG. 11 is a longitudinal cross section of FIG. 10 taken
`along line 11-11;
`FIG. 11A is a partial view of the longitudinal cross section
`of FIG. 11 depicting an alternative V-shaped annular groove;
`FIG. 11B is a partial view of the longitudinal cross section
`of FIG. 11 depicting a Second alternative annular groove
`configuration;
`FIG. 11C is a partial view of the longitudinal cross section
`of FIG. 11 depicting annular grooves of varying depth and
`width along the longitudinal length of the catheter;
`FIG. 12 is an enlarged perspective view of an embodiment
`wherein the transition Zone includes annular and longitudi
`nal grooves and is contiguous with the catheter distal tip;
`FIG. 13 is an enlarged perspective view of yet another
`embodiment of the transition Zone located along the catheter
`shaft;
`FIG. 14 is a longitudinal cross section of FIG. 13 along
`line 13–13;
`FIG. 15 is a perspective view of a guide catheter showing
`an application of the present invention;
`FIG. 16 is a perspective view of a guide catheter showing
`another application of the present invention;
`FIG. 17 is a schematic block diagram showing one
`method of manufacturing a catheter in accordance with the
`present invention;
`FIG. 18 is a schematic block diagram showing yet another
`method of manufacturing the present invention;
`FIG. 19 is a partial cross-sectional view of a distal portion
`of a catheter tube or guide catheter depicting a preferred
`distal construction;
`FIG. 20 is a detailed partial cross-sectional view of the tip
`region indicated in FIG. 19 showing a preferred tip con
`Struction; and
`FIG. 21 is a detailed partial cross-sectional view of an
`alternative embodiment of the tip configuration of FIG. 20
`depicting the inner tubular member extending to the distal
`end of the catheter tube.
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`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`FIG. 1 shows a section of a catheter 10 which is preferably
`a guiding catheter. Catheter shaft 11 is comprised of an inner
`tube 12 which is surrounded by a support member 14.
`Support member 14 is then surrounded by an outer tube 16.
`Inner tube 12 is represented in FIG. 1 by dashed lines and
`the Support member 14 is represented by a dotted line.
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`In the preferred embodiment, inner tube 12 is a thin
`walled PTFE (polytetrafluoroethylene) tube. This creates a
`Smooth, friction-free Surface for the passage of other devices
`through the inner tube. Support member 14 is a 304 stainless
`Steel wire, wound in a braided pattern around inner tube 12.
`Alternatively, Support member 14 could also be comprised
`of polymer fibers. Outer tube 16 is a polymer jacket which
`is placed through an extrusion process onto combined layers
`of inner tube 12 and support member 14. Preferably, outer
`tube 16 is comprised of PEBAX(R), a polyether block amide
`(PEBA) available from ATOMCHEM POLYMERS,
`Birdsboro, Pa. FIG. 6 shows a cross section of this con
`Struction.
`FIG. 2 is a drawing of a portion of catheter 10. Catheter
`shaft 11 is shown having a Section ground or abraded away
`to create a band 15 in which no material exists. As shown in
`FIG. 2, outer shaft 16 is removed to expose the Support
`member 14, and to create a band 15 which will be filled later
`with a different material.
`In the preferred embodiment, outer tube 16 is removed
`through an abrasion process. Specifically, the Section in
`which the band 15 to be created is brought in contact with
`a grinding wheel. Catheter shaft 11 is then rotated 360
`degrees to remove material circumferentially around the
`device. The grinding wheel is slowly advanced to increase
`the depth of the cut until the support member 14 is exposed.
`Although abrasion is the preferred mode of processing, the
`band 15 can be created in many different ways, some of
`which include alternate extrusion methods, cutting, and
`thermal processing.
`FIG. 3 is a plan view of the device depicted in FIG. 2 after
`the different material, filler material 18, has been placed in
`the band 15 to create the transition section 22. Filler material
`18 is an element which has different physical properties than
`the outer tube 16. For example, if the catheter shaft 11 is
`comprised of a flexible polymer, the filler material 18 may
`be either a rigid polymer, a rigid metal, or an even more
`flexible polymer. Likewise, if the catheter shaft 11 is com
`prised of a rigid polymer, the filler material 18 may be a
`more flexible polymer material.
`Filler material 18 is preferably a circular polymer tube
`with a diameter equal to the diameter of the band 15 and a
`length equal to the length of the band. The filler material 18
`is cut longitudinally to allow it to be placed over the catheter
`shaft 11 and onto the band 15. A processing sleeve is then
`loaded over both the catheter shaft and the band. The entire
`transition Section 22 is then Subjected to a heating Source to
`cause the materials to flow together. The processing sleeve
`allows for a Smooth Outer Surface following thermal pro
`cessing.
`In a preferred embodiment, the outer tube 16 is comprised
`of PEBAX having a durometer of 67D. Although 67D is
`preferred, the outer tube could be on the order of 40-72D.
`The filler material 18 is also comprised of PEBAX, but has
`a durometer of 25D. Although 25D is preferred, the outer
`tube could be on the order of 5-72D. In a preferred
`embodiment, the band 15 length is in the order of 0.1 to 0.75
`inches. The thickness of the band 15 varies with the amount
`of outer tube 16 material which is removed. For example, in
`an 8F guiding catheter, the diameter of the outer tube is in
`the order of 0.102-0.106 inches. After the material is
`removed, the diameter of the band 15 is on the order of
`0.092-0.096 inches. The diameter of the catheter shaft 11, or
`outer tube 16, also varies with the desired end use for the
`product. Aguiding catheter may be on the order of five to ten
`French, while a balloon angioplasty catheter will be on the
`order of two to five French.
`
`Page 19
`
`Medtronic Exhibit 1851
`
`

`

`7
`FIG. 4 shows the perspective view of the device when
`completed. Band 15 is replaced with filler material 18 in a
`circumferential pattern around the catheter shaft 11.
`FIG. 5 shows a specific application of this invention in the
`area of guiding catheters. Guiding catheter 40 is comprised
`of a catheter shaft 11 which is constructed as described
`above. Connected to the proximal end of the catheter shaft
`11 is a hub 30 and strain relief 32. The connection of these
`elements allows the physician to connect other devices to the
`guiding catheter 40 and to manipulate the device through the
`application of longitudinal or rotational forces. Connected to
`the distal end of the catheter shaft 11 is a distal tip 20. Distal
`tip 20 generally consists of a Softer, more flexible polymer
`which is connected to the catheter shaft 11 through a thermal
`process. In a preferred embodiment, distal tip 20 is com
`15
`prised of a PEBAX polymer tube having a durometer of
`35-40D. Distal tip 20 generally does not contain either the
`inner tube 12 or the Support member 14. However, it is
`possible for these elements to be present in a portion of the
`distal tip 20.
`The most distal section of the guiding catheter 40 is
`formed to correspond to a desired geometrical shape. This
`shape is determined by the Specific anatomy of the patient,
`and the amount of guide catheter back-out Support that is
`needed for the procedure. Generally, the guiding catheter has
`at least two bends at the distal end of the catheter shaft 11.
`These are the primary curve 26 and the secondary curve 28.
`These curves assist the physician in the placement of the
`device for treatment of the vessels.
`In order to Simultaneously maximize the amount of guide
`catheter back-out support and the flexibility of the distal end
`of the device, the present invention can be used. The present
`invention utilizes a catheter shaft which is relatively rigid to
`provide for good guide catheter back-out Support, and com
`bines that with a filler material 18 which is relatively
`flexible. Therefore, a transition section 22 is created which
`is more flexible to allow for easier and less traumatic guide
`catheter placement. Flexible transition Sections 22 can be
`located where tight radiuses are created due to the shape of
`the guide catheter to allow larger devices to pass through the
`curve with greater ease. The transition Sections 22 act as
`elastic joints which better accommodate devices by allowing
`the Shaft to Straighten. In this embodiment, the transition
`Sections 22 are created at the primary curve 26 or the
`Secondary curve 28. This placement of the transition Sec
`tions 22 provides the benefits of a flexible distal section and
`the benefits of a rigid distal Section Simultaneously. The
`transition Sections 22 can be located Strategically within the
`guide catheter shaft. Ideal locations include: a flexible
`transition Section 22 at the primary curve radius to allow
`Safer deep Seating of the guide, flexible transition Sections 22
`at radius locations within the curve Style to improve ease of
`device passage as it remains coaxial within the vessel lumen
`and a rigid transition Section 22 at the Secondary curve to
`provide maximum back-out Support.
`Transition Sections 22 can be applied to the main Shaft in
`as many locations as needed. Because the Support member
`14 and the inner tube 12 are continuous through the transi
`tion Section 22, a stronger bond is created. This is a key
`advantage over butt joints as described and used in the prior
`art. Most catheter shafts are made to be rigid the entire
`length of the catheter Shaft to ensure that correct StiffneSS
`occurs at the desired locations. The catheter Shaft does not
`need to be rigid the entire length to provide back-out
`Support. The present invention allows for the rigidity or
`flexibility to be added only where it is needed.
`In an alternative embodiment of the present invention, it
`is desired to start with a more flexible catheter shaft 11 and
`
`65
`
`45
`
`50
`
`55
`
`60
`
`5,911,715
`
`25
`
`35
`
`40
`
`8
`create Zones of rigidity through the use of the present
`invention. Bands 15 can be created in the catheter shaft 11
`and filled with a more rigid filler material 18, thereby
`creating a transition Section 22 which is more rigid.
`FIGS. 7 and 8 represent another embodiment in which it
`is desired to create bending planes within the catheter Shaft
`11. This also can be accomplished through the use of the
`present invention. The catheter can be processed as
`described above, but instead of grinding the band 15 in a 360
`degree manner, opposing Sides of the catheter shaft 11 may
`be ground down and then filled with a more flexible filler
`material 18 to create a plane in which the transition element
`may bend. Alternatively, a flexible catheter shaft 11 can be
`ground down on opposing sides and then filled with a more
`rigid filler material 18, to create planes in which the catheter
`may not bend.
`In another embodiment of the present invention, the filler
`material 18 may be a composite or a blend of two different
`Substances. Specifically, it may be comprised of a polymer
`tube which has a Spring coil embedded therein to impart
`different flexibility in that section. It may also be comprised
`of two or more polymer Sections that have physical prop
`erties that are different from each other and from the catheter
`shaft 11.
`Yet another embodiment of the present invention is shown
`in FIG. 9. FIG. 9 shows a catheter assembly generally at 50,
`which includes a dilatation catheter 52 positioned over guide
`wire 53, within guide catheter 54. Guide catheter 54 can be
`similar to t