`Fugoso et al.
`
`54) FLEXIBLE CATHETER
`
`(75) Inventors: Mauricio L. Fugoso, Chula Vista;
`Karen M. Rowean, San Diego;
`Michelle E. Siebold, Carlsbad, all of
`Calif.
`
`73 Assignee: Medtronic, Inc., Minneapolis, Minn.
`
`USOO596.1510A
`Patent Number:
`11
`(45) Date of Patent:
`
`5,961,510
`Oct. 5, 1999
`
`5,599,326 2/1997 Carter ...................................... 604/282
`5,690,613 11/1997 Verbeek .................................. 604/103
`5,702.373 12/1997 Samson ............................... 604/280 X
`
`Primary Examiner-Corrine McDermott
`Assistant Examiner AT Nguyen
`Attorney, Agent, or Firm-Dianne Plunkett Latham; Harold
`R. Patton
`ABSTRACT
`57
`21 Appl. No.: 08/938,045
`A medical catheter comprising a distal shaft having a greater
`21 p
`9
`flexibility than the proximal shaft. The proximal shaft has a
`22 Filed:
`Sep. 26, 1997
`(51) Int. Cl. ............................................... A6M2500 helical endportion of reduced outer diameter which is
`52 U.S. C.
`6041524; 604/526
`integral with and extending from the distal end of the
`52)
`-rr.
`- - - -
`s
`proximal shaft. The helical end portion slidingly fits within
`58 Field of Search ..................................... 60,523, 524,
`portion of the proximal end of the distal shaft. The helical
`604/264, 96, 526; 600/435
`end portion is bonded to at least a portion of the distal shaft
`to form a fluid-tight seal. The pitch of the helical end portion
`may be constant or variable. The helical turns may be
`References Cited
`abutting or Spaced apart. Aguidewire Shaft centrally extends
`U.S. PATENT DOCUMENTS
`longitudinally through the proximal and distal shaft Such
`604/96
`4,960,410 10/1990 Pinchuk
`that fluid can be transmitted through the proximal and distal
`2 - - -2
`IICIllK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
`-
`0
`... 604/102
`5,328,472 7/1994 Steinke et al. ...
`5,410,797 5/1995 Steinke et al. ............................ SE shaft, exterior to the guidewire shaft.
`5,454,795. 10/1995 Samson ............
`... 604/282
`5,460,608 10/1995 Lodin et al. .............................. 604/96
`21 Claims, 3 Drawing Sheets
`
`56)
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`Medtronic Exhibit 1044
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`1
`FLEXBLE CATHETER
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`5,961,510
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`FIELD OF THE INVENTION
`The present invention relates to a catheter of constant
`outer diameter having a flexible, non-kinking shaft and more
`particularly to a catheter having a flexible distal shaft portion
`and a Stiffer proximal shaft portion.
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`BACKGROUND OF THE INVENTION
`Percutaneous transluminal coronary angioplasty (PTCA)
`is used to increase the lumen diameter of a coronary artery
`partially or totally obstructed by a build-up of cholesterol
`fats or atherOSclerotic plaque. Typically a first guidewire of
`about 0.038 inches in diameter is steered-through the vas
`cular System to the Site of therapy. A guiding catheter, for
`example, can then be advanced over the first guidewire to a
`point just proximal of the Stenosis. The first guidewire is
`then removed. A balloon catheter on a smaller 0.014 inch
`diameter Second guidewire is advanced within the guiding
`catheter to a point just proximal of the Stenosis. The Second
`guidewire is advanced into the Stenosis, followed by the
`balloon on the distal end of the catheter. The balloon is
`inflated causing the Site of the Stenosis to widen. The
`dilatation of the occlusion, however, can form flaps, fissures
`and dissections which threaten reclosure of the dilated vessel
`or even perforations in the vessel wall.
`Although the dimensions in the above example are Suited
`to the coronary arteries, any body lumen can be treated by
`percutaneous transluminal angioplasty (PTA), including the
`Vas deferens, ducts of the gallbladder, prostate gland,
`trachea, bronchus and liver. The body lumens range in
`diameter from Small coronary vessels of 3 mm or less to 28
`mm in the aortic vessel. The invention applies to acute and
`chronic closure or reclosure of body lumens.
`It is advantageous for catheter shafts to have a Stiff
`proximal end for pushability and a more flexible distal end
`for better tracking through tortuous lesions. Abutting Stiff
`tubular materials to more flexible tubular materials results in
`a point at which kinking can occur. What is needed is a
`transition area therebetween to provide a Smooth transition
`between the stiff proximal section and the more flexible
`Section of the catheter shaft and thereby reduce kinking.
`U.S. Pat. No. 4,960,410 to Pinchuk for “Flexible Tubular
`Member for Catheter Construction” discloses a spirally cut
`tubular member which extends through the balloon to the
`distal end of the catheter. The tubular member includes a first
`relatively Stiff tube that is Spirally cut along a distal portion
`and also includes a Second more flexible tube that covers the
`spirally cut distal portion of the stiff tube to make a distal
`portion of the tubular member more flexible than a proximal
`portion of the elongated tubular member.
`U.S. Pat. No. 5,599,326 to Carter for “Catheter with
`Multi-Layer Section” discloses an interior stiffener compris
`ing a spirally cut tube member and an exterior tube member.
`SUMMARY OF THE INVENTION
`It is an object of the invention to provide a Smooth,
`flexible and kink-resistant transition between the catheter
`shaft stiff proximal end and the more flexible distal end
`while retaining a uniform outer diameter between the proxi
`mal shaft portion and the distal shaft portion. The present
`invention is accomplished by providing an apparatus com
`prising a distal Shaft having a greater flexibility than the
`65
`proximal shaft. The proximal shaft has a helical end portion
`of reduced outer diameter which is integral with and extend
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`2
`ing from the distal end of the proximal shaft. The helical end
`portion slidingly fits within a portion of the proximal end of
`the distal shaft. The helical end portion is bonded to at least
`a portion of the distal shaft to form a fluid-tight seal. The
`pitch of the helical end portion may be constant or variable.
`The helical turns may be abutting or Spaced apart. A
`guidewire Shaft centrally extends longitudinally through the
`proximal and distal Shaft Such that fluid can be transmitted
`through the proximal and distal shaft, exterior to the
`guidewire shaft.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a plan view of the catheter of the invention;
`FIG. 2 is a cross-section of the distal end of the catheter
`of FIG. 1; and
`FIG. 3 is a cross-section of the transition section of the
`catheter of FIG. 2.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`Referring to FIG. 1, Applicant's catheter 10 is comprised
`of a balloon 15, distal shaft 20, transition 25, proximal shaft
`30 and manifold 35. The spirally cut transition 25 is
`designed to provide a Smooth transition between the Stiff
`proximal shaft 30 and the more flexible distal shaft 20. This
`reduces kinking and prevents guidewire lockup or damage,
`especially during backloading the guidewire into the cath
`eter. In instances where the catheter is deep into the guide
`catheter, the flexible transition allows the catheter to bend
`with the bends in the guide catheter instead of butting
`against the wall of the guide catheter, thus increasing the
`trackability of the distal section which is out in the torturous
`vessel. A conventional over-the-wire design consists of a
`guidewire shaft 50 which defines a guidewire lumen 45
`running the length of the catheter 10. The guidewire shaft 50
`is coaxially disposed within the proximal shaft 30. The inner
`diameter and the outer diameter of the distal end of the
`proximal shaft 30 is necked down at 65. The transition 25
`beginning at the neck 65 and ending at the distal end of the
`proximal shaft 30 is approximately 1 inch (2.54 cm) long.
`The outer diameter of the proximal shaft 30 before necking
`is approximately 0.041 inches (1.04 mm). After necking 65,
`the outer diameter of the proximal shaft 30 is greater than
`0.0315 inches (0.800 mm), preferably 0.034 inches (0.86
`mm) which will yield optimum in/deflation times. The inner
`diameter of the proximal shaft 30 after necking down is
`approximately 0.029 inches (0.737 mm).
`The distal end of the proximal shaft 30 is spirally cut into
`a coil to define the transition 25. A constant pitch of 24
`degrees with 2 coils per mm is preferred. Other pitches or
`variable pitches may be preferred in certain alternate appli
`cations. Smaller angles lead to leSS flexibility due to more
`coils per the Specified distance and Vice versa. An example
`of this would be using this type of transition in place of a
`Strain relief at the proximal end of the catheter next to the
`manifold. In this application, fewer coils per the Specified
`distance would be more desirable. The more distal you move
`down the catheter toward the balloon, the more coils per the
`specified distance, thus the more flexible the transition. To
`create the spiral cut, a 0.0280 inch mandrel is inserted into
`the distal end of the proximal shaft 30 which is then cut
`using any conventional means Such as a razor blade main
`tained at a fixed angle to the cutting Surface. This can be
`done manually with a fixture maintaining the razor at a fixed
`angle while the catheter Section is rotated using a motorized
`device with a mounting chuck. The operator holds the razor
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`Medtronic Exhibit 1044
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`blade manually against the cutting Surface. An alternate to
`this method could be that the razor blade is held within a
`fixture that provides the preSSure required to enable the
`cutting. The distal end of the proximal shaft 30 should be
`trimmed to within 1 mm-2 mm from the last distal coil. The
`coils should be cut all the way through. The length of the
`proximal shaft 30 between the neck 65 and the first proximal
`spiral 80 should be about 0.118 inches (3 mm). The length
`of the spiraled area should be about 0.748 inches (19 mm).
`For optimum tracking, flexibility, and kink resistance, tran
`sition 25 is preferably not less than about 34 inches. The
`length of transition 25 could vary depending on where along
`the catheter it is placed. The length between the last distal
`spiral 80 and the distal end of the proximal shaft 30 is
`preferably about 0.059 inches (1.50 mm). The length from
`the neck 65 to the distal end of the distal shaft 20 is about
`11.81 inches (300.0 mm). The spirally cut transition 25 is
`designed to provide a Smooth transition between the Stiff
`proximal shaft 30 and the more flexible distal shaft 20.
`Having a more gradual Stiffness gradient reduces kinking
`and increases flexibility for better tracking. Transition Sec
`tion 25 is located on the catheter Shaft in Such a position to
`be compatible with the guide catheter. Guiding catheters
`often have preset curves at the distal end or Segments of
`differing flexibility. The transition 25 on a catheter such as
`a balloon catheter 10 should be aligned with the preset curve
`or a Segment of Suitable flexibility So that an advantageous
`length of the balloon catheter protrudes from the guiding
`catheter into the vessel. The transition 25 is placed such that
`it is far enough back on the balloon catheter 10 so that the
`most flexible portion of the balloon catheter 10 resides in the
`vessel. In instances where the catheter is very deep into the
`guiding catheter, the flexible transition is advantageous in
`that it allows the catheter 10 to track the bends in the guiding
`catheter, thus improving the tracking of the distal portion in
`the vessel and not kinking at that point.
`The outer diameter of the distal shaft 20 is approximately
`0.041 inches (1.04 mm) over the transition section 25. The
`proximal end of the distal shaft 20 is coaxially slid over the
`distal end of the proximal shaft 30 to within about 0.5 mm
`40
`of the neck 65, while the assembly is still on the 0.0280 inch
`mandrel. The proximal end of the distal shaft 20 is bonded
`at the neck 65 of the proximal shaft 30 using any conven
`tional means Such as adhesive 75, heat bonding or welding.
`The preferred means is to place a drop of U.V. adhesive, as
`for example #3311 Loctite(R) (manufactured by Loctite Corp.
`in Hartford Conn.) into the gap, wick it under the distal shaft
`20, slide the proximal end of the distal shaft 20 up to the
`neck 65 then cure the adhesive while rotating the parts. Form
`a bond 70 which is about 1 mm long. The adhesive should
`not extend beyond the second spiral 80. After bonding, the
`0.0280 inch mandrel is removed.
`The proximal shaft 30 may be formed of a stiff material
`such as polyimide. Other materials which would be suitable
`for the necessary pushability include PEEK. Those skilled in
`the art would recognize that any material which has high
`column Strength in a thin walled configuration of the appro
`priate size would be suitable. The distal shaft 20 may be
`formed of a more flexible material such as Polyethylene
`(PE) or Nylon. The proximal shaft 30 may have several
`visual Marker Bands 60 to indicate the various approaches,
`as for example, the brachial approach. The distal end of the
`proximal shaft's material could be heat laminated to the
`more flexible material of the distal shaft 20 proximal end.
`The distal shaft 20 may be optionally necked down to
`improve tracking at a point distal to the transition 25. The
`outer diameter of the distal shaft 20 before necking is
`
`4
`approximately 0.041 inches (1.04 mm). The distal shaft 20
`is necked down to a first neck with an outer diameter of
`approximately 0.038 inches which is approximately 0.5
`inches from the distal end of the transition 25. The distance
`between neck-down 65 and the first neck of the distal shaft
`20 is 1.5 inches. The distal shaft 20 is necked down again
`into a Second neck distal to the first neck to an Outer diameter
`of approximately 0.034 inches beginning approximately 5
`inches proximal of the distal end of the balloon 15. The
`distal Shaft 20 first and Second neck produce better tracking.
`The first and second neck downs in the distal shaft 20 are
`sized to maximize tracking VS. inflation/deflation time. The
`distance between neck-down 65 and the proximal end of
`balloon 15 is 11.81 inches.
`The guidewire shaft 50 is made of High Density Poly
`ethylene (HDPE). It has an inner diameter of 0.017 inches
`(0.43 mm) suitable for passing standard 0.014 inch
`guidewires. Those skilled in the art would recognize that the
`dimension varies depending on the application and the size
`of device being passed. The outer diameter of the guidewire
`shaft 50 is 0.023 inches.
`For the Balloon 15 any conventional material may be used
`such as Nylon, polyethylene (PE) or polyethylene tereph
`thalate (PET). The balloon typically has one or more marker
`bands 40 made of a material such as platinum/iridium for
`Visualization under fluoroscopy. Those skilled in the art
`would recognize that any conventional balloon design would
`be suitable. The proximal end of the balloon 15 is affixed to
`the distal end of the distal shaft 20. The distal end of the
`distal Shaft 20 can be flared larger to accommodate bonding
`of the balloon 15 to the distal end of the distal shaft. The
`balloon 15 is in fluid communication with the inflation
`lumen 55.
`Whereas Applicant's invention depicts a shaft transition
`for an over-the-wire coronary catheter those skilled in the art
`would recognize that Such a transition could be used for any
`catheter including rapid exchange or fixed wire catheters and
`other applications Such as peripheral etc. The preceding
`Specific embodiments are illustrative of the practice of the
`invention. It is to be understood, however, that other expe
`dients known to those skilled in the art or disclosed herein,
`may be employed without departing from the Scope of the
`appended claims.
`
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`No.
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`Component
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`1O
`15
`2O
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`3O
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`40
`45
`50
`55
`60
`65
`70
`75
`8O
`
`Catheter
`Balloon
`Distal Shaft
`Transition Section
`Proximal Shaft
`Manifold
`Balloon Marker Bands
`Guidewire Lumen
`Guidewire Shaft
`Inflation Lumen
`Shaft Visual Marker Bands
`Neck-Down
`Bond
`Adhesive
`Spiral
`
`What is claimed is:
`1. A medical catheter comprising:
`a proximal Section having a proximal end and a distal end;
`a transition Section having a proximal end and a distal
`end;
`a distal Section having a proximal end and a distal end;
`
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`5
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`a balloon having a proximal end and a distal end, the distal
`end of the proximal Section forming the transition
`Section, the distal end of the transition Section being
`coaxially affixed to and covered by the proximal end of
`the distal Section, the distal end of the distal Section
`being affixed to the proximal end of the balloon;
`a guidewire shaft defining a guidewire lumen, the
`guidewire shaft extending longitudinally and coaxially
`throughout the proximal Section, the transition Section,
`the distal Section and the balloon with enough clearance
`between an outer diameter of the guidewire Shaft and
`an inner diameter of the proximal Section, transition
`Section, distal Section and balloon So as to define an
`inflation lumen therebetween and maintain fluid com
`munication with the balloon; and
`15
`the transition Section further comprising a necked-down
`area of reduced outer diameter beginning at the proxi
`mal end of the transition Section, the area of reduced
`outer diameter having a spirally cut distal portion to
`increase flexibility and kink resistance, the distal end of
`the transition Section ending proximal to the proximal
`end of the balloon.
`2. The catheter according to claim 1 wherein the distal
`Section is more flexible than the proximal Section and the
`transition Section is of intermediate flexibility to the proxi
`mal Section and to the distal Section.
`3. The catheter according of claim 1 wherein the Spiral cut
`extends completely through the thickness of the transition
`Section.
`4. The catheter of claim 1 wherein the spiral cut is at a
`constant pitch.
`5. The catheter of claim 4 wherein the pitch is at 24
`degrees with two spiral coils per mm.
`6. The catheter of claim 1 wherein the spiral cut is at a
`variable pitch.
`7. The catheter according of claim 1 wherein the spiral cut
`is continuous.
`8. The catheter according of claim 1 wherein the proximal
`Section is made of polyimide.
`9. The catheter according of claim 1 wherein the distal
`Section comprises a material Selected from polyethylene and
`nylon.
`10. The catheter according of claim 1 wherein the
`guidewire shaft is made of high density polyethylene.
`
`6
`11. The catheter according of claim 1 wherein the length
`of the spirally cut portion is not less than 19 mm (0.748
`inches).
`12. A medical catheter comprising:
`a proximal shaft having an outer diameter;
`a distal shaft having greater flexibility than the proximal
`shaft, a proximal portion of the proximal shaft having
`an outer diameter that is Substantially the Same as the
`outer diameter of the distal shaft, the proximal shaft
`further comprising:
`a helical end portion of reduced outer diameter integral
`with and extending from a distal end of the proximal
`shaft, the helical end portion slidingly fitting within a
`portion of a proximal end of the distal Shaft, and
`the helical end portion being bonded to the distal shaft
`Over at least a proximal portion of the helical end
`portion to form a fluid-tight Seal.
`13. The catheter according to claim 12 wherein the helical
`end portion is formed from a reduced diameter portion of the
`proximal shaft.
`14. The catheter according to claim 12 wherein the helical
`portion has a constant pitch.
`15. The catheter according to claim 12 wherein the helical
`portion has a variable pitch.
`16. The catheter according to claim 15 wherein the helical
`portion has a pitch which is greater at a distal end than at a
`proximal end.
`17. The catheter according to claim 12 wherein the helical
`portion is defined by one or more turns and wherein at least
`a portion of the turns of the helical portion are in abutting
`relation.
`18. The catheter according to claim 12 wherein at least a
`portion of the turns of the helical portion are Spaced apart.
`19. The catheter according to claim 12 also comprising a
`tube extending longitudinally within the proximal shaft and
`the distal shaft such that a fluid can be transmitted through
`the proximal shaft and the distal shaft exterior to the
`centrally extending tube.
`20. The catheter according to claim 12 also comprising a
`balloon affixed to the distal shaft, the balloon being in fluid
`communication with the proximal shaft.
`21. The catheter of claim 19 wherein the centrally extend
`ing tube is adapted to receive a guidewire.
`
`k
`
`k
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`k
`
`k
`
`k
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