BSC USP 8,048,032
`Exhibit 1019
`
`Page 1 of 14
`
`United States Patent
`Steinke et al.
`
`[19]
`
`[58]
`
`[56]
`
`[75]
`
`[54] CATHETER WITH FLEXIBLE SIDE PORT
`ENTRY
`Inventors: Thomas A. Steinke, San Diego;
`Leonard F. Briggs, Chula Vista;
`Garry E. Rupp, San Diego, all of
`Calif.
`[73] Assignee. Medtronic, Inc., Minneapolis, Minn.
`[211 AppI. No.: 919,672
`[22] Filed:
`JuL 27, 1992
`mt. Cl.~
`[51]
`U.S. Cl
`[52]
`
`A61M 29/00
`604/102; 604/96;
`604/282; 606/194
`604/96, 102, 280, 282;
`Field of Search
`128/656—658, 772; 606/191, 192, 194
`References Cited
`U.S. PATENT DOCUMENTS
`4,594,074
`6/1986
`Anderson Ct al
`3/1987
`4,648,384
`Schmukler
`4,723,936
`2/1988
`Buchbinder Ct a!
`4,748,982
`6/1988
`Horzewski Ct al
`Bonzel
`4,762,129
`8/1988
`Horzewski et al
`4,771,777
`9/1988
`Mueller, Jr. et al
`4,790,315 12/1988
`Karcher et al
`4,804,358
`2/1989
`4,832,028
`5/1989
`Patel
`4,838,268
`6/1989
`Keith et al
`Conway et a!
`4,877,031 10/1989
`4,892,519
`1/1990
`Songer et a]
`Goldberger
`4,909,252
`3/1990
`Solar et a!
`4,917,666 4/1990
`4,927,413
`5/1990
`Hess
`Eutencuer et al
`4,943,278
`7/1990
`4,944,740
`7/1990
`Buchbinder et al
`
`604/270
`128/1
`604/95
`128/344
`128/344
`128/344
`128/344
`600/17
`128/344
`128/344
`128/344
`604/96
`606/194
`604/95
`604/95
`604/96
`606/194
`
`I1111111111111III11111liii!111111111111111I1~II[11111111111111111 11111liii
`
`US005328472A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,328,472
`Jul. 12, 1994
`
`606/194
`604/95
`606/192
`606/32
`128/898
`606/194
`604/95
`606/194
`604/96
`
`4,944,745 7/1990
`Sogardetal
`Buchbinder Ct al
`4,976,689 12/1990
`Crittenden et al
`4,988,356
`1/1991
`5,000,753
`Hagen et al
`3/1991
`5,040,548
`8/1991
`Yock
`5,061,273 10/1991
`Yock
`5,125,895
`6/1992
`Buchbinder et al
`Leopold
`5,154,725 10/1992
`5,156,594 10/1992
`Keith
`FOREIGN PATENT DOCUMENTS
`European Pat. Off
`A61M 29/02
`0420486
`3/1991
`8803389
`5/1988
`PCT Int’l Appl
`A61B 10/00
`9108013
`6/1991
`PCT Int’l Appl
`A61M 25/10
`Primary Examiner—C. Fred Rosenbaum
`Assistant Examiner—Corrine Maglione
`Attorney, Agent, or Firm—Dianne M. F. Plunkett;
`Harold R. Patton
`ABSTRACT
`[57]
`An improved balloon catheter is disclosed which is
`comprised of two jacketed spring coils placed end-to.
`end and joined by a linking element which contains a
`lumen communicating between the inflation lumens
`formed by the two spring coils. A side port entry to a
`guidewire lumen, which extends through the distal coil
`to the distal end of the catheter, is located in the transi
`tion region formed by the linking element. The linldng
`element may include two polyimide tubes or may be a
`multilunien insert. The catheter is stiffened by a core
`wire which is bonded directly to the spring coils. A
`catheter comprised of a single spring coil with a side
`port entry in the coil is also disclosed, and a method and
`apparatus for crimping the coil to create the entry.
`
`12 Claims, 7 Drawing Sheets
`
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`July 12,1994
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`Page 9 of 14
`
`CATHETER WITH FLEXIBLE SIDE PORT ENTRY
`
`5
`
`BACKGROUND OF THE INVENTION
`The technique of eliminating a vascular stenosis by
`dilating a balloon on a catheter placed within the steno
`sis was developed by Dr. Andreas Gruntzig. The first
`marketable catheters for angioplasty were “fixed wire”
`catheters, in which a core or guidewire was fixed within
`the catheter to stiffen it so that it could be pushed into
`position in the vascular system.
`Dr. John Simpson and Dr. Edward Robert subse
`quently developed an “over-the-wire” catheter
`in
`which a guidewire was slidably placed within a lumen
`of the catheter. This system provided reasonably easy
`placement of the catheter because the guidewire was
`first positioned beyond the stenosis and the catheter was
`then slid into place over it. Although over-the-wire
`catheters generally have a larger profile than fixed wire
`catheters, the guidewire can be much more easily posi- 20
`tioned in the vascular system than a fixed wire catheter.
`Both over-the-wire and fixed wire catheters are usu
`ally made using polymer tubing to form the catheter
`body. In some catheters, however, the catheter shaft is
`formed of a spring coil (a helically wound wire) jack- 25
`eted on the outside or inside so that it is sealed to form
`a
`lumen. For example, U.S. Pat. Nos. 4,976,689,
`4,944,740, 4,917,666 and 4,723,936 issued to the assignee
`of the present
`invention describe such catheters. Al
`though more expensive and more complicated to make
`than polymer catheters, spring coil catheters have cer
`tain advantages. They allow flexibility in the catheter
`while providing greater axial stiffness than a typical
`polymer extrusion. As a result,
`the catheter is very
`“pushable”, i.e., axial force at one end is transmitted to
`the other end. In addition, kinking of the catheter as it
`bends around curves is minimized. The use of flat wire
`rather than round wire is preferred because it has
`greater resistance to compression and less tendency to
`deform.
`An advantage of over-the-wire catheters is that if a
`catheter has to be exchanged for a larger or smaller
`catheter,
`the guidewire can be left
`in place and the
`catheter withdrawn over it and another catheter slid
`into place over it. A difficulty with the exchange proce
`dure is that it is difficult to keep the guidewire in place,
`because removing the catheter requires removal of the
`guidewire and subsequent recrossing of the stenosis. To
`avoid this problem, very long “exchange” guidewires,
`more than twice the length of the catheter, are used so
`that they can be separately held in place while the cath
`eter is withdrawn. In addition, shorter guidewires have
`been made, which are lengthened by attachment of an
`extension wire during the exchange process in order to
`render them the length of a long exchange wire. Unfor- 55
`tunately, such long guidewires and extension wires
`require an additional person to hold the guidewire dur
`ing the catheterization process and are somewhat diffi
`cult to use.
`This problem was solved by the development of cath- 60
`eters which have shorter guidewire lumens, so that the
`guidewire exits from the catheter closer to the balloon
`than to the proximal end of the catheter. Thus the
`guidewire can be anchored or held by the physician as
`he or she removes the catheter from the body and the 65
`exchange~ occurring over the shorter guidewire lumen.
`One version of such a catheter is shown in U.S. Pat.
`No. 4,762,129 (and Bi 4,762,129)
`issued to Bonzel,
`
`1
`
`5,328,472
`
`2
`where the guidewire lumen passes through the balloon
`and exits immediately proximal
`to the balloon. The
`guidewire lumen and inflation lumen are of a “bilumen”
`or
`“biaxial” configuration in which the guidewire
`lumen runs parallel
`to the inflation lumen. A similar
`system is shown in U.S. Pat. No. 4,748,982 issued to
`Horzewski, et al., and in U.S. Pat. No. 4,988,356 issued
`to Crittenden,
`in which the guidewire lumen, which
`runs parallel to the inflation lumen, contains a slit cx
`10 tending its length so that the guidewire can be removed
`from the lumen through the slit at a point immediately
`proximal to the balloon.
`These bilumen designs can be relatively easy to man
`ufacture because they can be made from a single extru
`~ sion of the shaft and guidewire lumen together. In addi
`tion, they allow use of a slit guidewire lumen. Some
`times, however, they have a larger profile than might be
`desired and poor guidewire movement.
`Examples of bilumen rapid exchange catheters on the
`market are ACS’ Alpha ms catheter and ACS’ RX TM
`catheter. In the Alpha TM catheter, a hypotube (stain
`less steel tube) forms the proximal end of the catheter
`and a bilumen extrusion the distal portion. The bilumen
`portion is slit so that
`the guidewire can be removed
`from it at varying positions as shown in the Horzewski,
`et al., patent mentioned above. In the RX TM catheter,
`the entire catheter is a single bilumen extrusion,
`the
`proximal portion of which contains a core wire. A side
`30 entry is cut into the guidewire lumen near the balloon.
`In rapid exchange catheter designs such as those in
`Yock, U.S. Pat. Nos. 5,040,548 and 5,061,273, the short
`guidewire lumen is coaxial with respect to the inflation
`lumen, but exits (or enters) in a side port at
`least 10
`centimeters from the distal
`tip of the catheter. (The
`Yock disclosure suggests a lumen of 10 or more centi
`meters; in catheters on the market, the coaxial
`lumen
`varies from about 9 to about 35 centimeters in length.)
`Coaxial construction has provided certain advantages
`~ such as smaller profile catheters and better guidwire
`movement.
`However, in these catheters, the construction of the
`distal guidewire entry area or “transition region” has
`posed a challenge. The inflation lumen must be isolated
`~ from the distal port to prevent exit of the inflation fluid
`to the exterior. In some designs, the transition region is
`not strong enough to avoid distal kinking.
`In others,
`abrupt changes in stiffness from one part of the catheter
`to another may occur. In yet others, the transition re
`~ gion may be too stiff, preventing its placement in the
`coronary arteries.
`An example of a coaxial rapid exchange catheter on
`the market is Schneider’s Piccolino TM . In this catheter,
`the entire inflation lumen appears to be formed of one
`piece, and a core wire extends through the proximal
`portion, through the transition region and into the distal
`portion. The guidewire lumen is located in the distal
`end of the inflation lumen and appears to be fused into
`position in the transition area. An entry is cut into the
`proximal end of the guidewire and adjacent fused area.
`In SciMed’s Express TM catheter, a hypotube forms
`the proximal segment and a separate hypotube segment
`formed into a crescent shape is attached to the distal end
`of the proximal hypotube, creating a trough in which
`the guidewire lumen is located. A short coil jacketed by
`the inflation lumen surrounds the guidewire lumen,
`reinforcing the transition. The remaining distal segment
`of the catheter is made of standard coaxial extrusions.
`
`

`

`Page 10 of 14
`
`5,328,472
`
`5
`
`3
`It would be desirable to develop a catheter which
`allows rapid exchange, has the benefits of a coaxial
`guidwire lumen, has the advantages of a spring coil
`design, and which can be designed for appropriate but
`varying flexibility along the length of the catheter,
`without abrupt changes in stiffness, or an undesirably
`stiff transition region.
`SUMMARY OF THE INVENTION
`The present
`invention is directed to an improved 10
`catheter and method of making and using same which
`can be manufactured with variable stiffness characteris
`tics, appropriate flexibility, and desired amounts of axial
`stiffness.
`In one aspect, the invention is a method of making a 15
`catheter including the following steps:
`selecting two tubular members for the catheter body,
`each defining a lumen;
`placing the tubular members end-to-end;
`spacing the ends of the tubular members from each 20
`other to create a transition region therebetween;
`and
`providing a linking element in the transition region
`defining a lumen to communicate between the lu
`mens of the two tubular members, so that by vary- 25
`ing the characteristics of the tubular members and
`the linking element, the handling characteristics of
`the catheter can be controlled.
`In another aspect, the invention is a catheter body
`comprised of
`two tubular members having lumens 30
`placed end-to-end and spaced apart by a linking element
`having a lumen communicating between the lumens of
`the two tubular members. Generally, the method also
`includes the steps of providing a side port entry in the
`transition region and a third tubular member within the 35
`distal tubular member to act as a guidewire lumen. The
`catheter also preferably includes such a third tubular
`member. The first two tubular members are preferably
`formed of spring coils and the linking element is a flexi
`ble tube, sometimes two flexible tubes, usually formed 40
`of polyisnide. Sometimes the linking element is a single
`multilumen element comprising both the guidewire
`lumen and a lumen communicating between the infla
`tion lumens of the spring coils.
`In another aspect, the invention is a catheter having a 45
`spring coil shaft defining a lumen and a side port and
`having a distal and proximal end. The catheter prefera
`bly includes a balloon located generally at the distal end
`of the shaft, the balloon having a distal and a proximal
`end, and a lumen extending from the distal end to the 50
`side port, the lumen adapted to receive a guidewire in a
`sliding fit. The distal end of the balloon is sealed to the
`lumen and the proximal end of the balloon is sealed to
`the shaft. The shaft is usually jacketed with polyethyl
`ene and a core wire is bonded to the shaft to stiffen the 55
`catheter. Preferably the spring coil shaft is formed of
`two spring coils placed end-to-end to define a transition
`region therebetween; the side port entry located in the
`transition region, as described in more detail above.
`Alternately, the entry may be located in a single spring 60
`coil shaft, and one or more flexible tubes, preferably
`polyimide, sealed adjacent
`the entry to communicate
`between the distal and proximal ends of the coil.
`In another aspect, the invention is a method of using
`a catheter including the following steps:
`providing a catheter including a spring coil shaft
`defining a lumen and a side port and having a distal~
`and proximal end, a lumen extending from the
`
`65
`
`4
`distal end to the side port, said lumen adapted to
`receive a guidewire in a sliding fit and a treatment
`region located at the distal end of the shaft;
`providing a guiding catheter;
`providing a guidewire;
`inserting the guiding catheter into a vascular system
`having a stenosis;
`threading the guidewire through the vascular system
`and through the stenosis;
`threading the catheter over the guidewire to locate
`the treatment means with respect to the stenosis;
`and
`withdrawing the catheter.
`Preferably,
`the method also includes the following
`steps:
`providing a second catheter including a spring coil
`shaft defining a lumen and a side port and having a
`distal and proximal end, a lumen extending from
`the distal end to the side port, said lumen adapted
`to receive a guidewire in a sliding fit and a treat
`ment region located at the distal end of the shaft;
`inserting the second catheter over the guidewire;
`treating the stenosis; and
`withdrawing the second catheter.
`Generally, the treatment means of the catheter is a
`dilatation balloon having a distal end sealed to the
`lumen and a proximal end sealed to the shaft, and the
`step of treating the stenosis includes inflating the bal
`loon to dilate the stenosis. The spring coil shaft of the
`catheter is preferably formed of two spring coils located
`end-to-end and defining a transition region therebe
`tween; the side port located in the transition region, and
`the catheter most preferably has one or more of the
`additional features already described above.
`In another aspect, the invention is a catheter includ
`ing an elongated shaft defining a lumen and a core wire
`for stiffening the shaft, where the core wire is bonded
`directly to the shaft. Preferably the shaft is a spring coil
`and the core wire is brazed to it. Most preferably, the
`shaft is comprised of two spring coils spaced end-to-end
`and the core wire is fixed to both spring coils, and the
`catheter has one or more of the additional features al
`ready mentioned.
`In another aspect, the invention is a method of creat
`ing a side entry along the length of the shaft of a cathe
`ter having the following steps:
`providing a spring coil shaft;
`connecting the coils together in an area of the shaft;
`crimping some of the connected coils sufficiently to
`create an entrance to the shaft while maintaining a
`lumen through the crimped coils.
`The step of connecting the coils generally includes
`brazing the coils to render them more shapable and may
`include welding them to a core wire extending through
`the coil. One or more core wires may be inserted
`through the coils to be crimped to maintain a lumen
`through the crimped coils. The core wire is usually
`0.014” in diameter and may be a hypotube mandrel
`shaped in a “U” or crescent. One or more flexible shafts
`may be inserted into the lumen to carry the inflation
`fluid. A guidewire lumen is usually inserted in the distal
`portion of the coils and opens to the exterior of the
`catheter at the side port entry.
`In yet another aspect, the invention is apparatus for
`creating a side port entry in a spring coil shaft including
`means for retaining the spring coil
`in a fixed position,
`means for crimping a length of spring coil, and means
`
`

`

`Page 11 of 14
`
`5
`
`15
`
`5,328,472
`
`5
`6
`for adjusting the crimping means between crimping and
`into the balloon. An inner lumen 10 located within the
`non-crimping position.
`catheter body extends through the balloon, and the
`in a fixed
`The means for retaining the spring coil
`distal end of the balloon is sealed to the inner lumen
`position are usually two blocks forming a space therebe
`near the distal end of the lumen.
`tween for holding the spring coil. The crimping means
`The inner lumen exits to the exterior of the catheter
`is a tongue having a lower edge extending lengthwise
`through a side port entry 12 distal to the proximal end
`with respect to the coil. The two blocks are movable
`of the catheter 8, but proximal to the balloon. Prefera
`relative to each other, via an arm attached to an eccen
`bly the side port entry is located about 20 centimeters
`tric cam, so that coils of different sizes can be accommo
`from the distal tip 14 of the catheter. A guidewire 1~
`dated. The tongue can be variably positioned with re
`10 can be slidingly received within the inner lumen. The
`spect to the spring coil via an arm attached to an eccen
`length of the balloon will vary but,
`in the preferred
`tric cam. The tongue is removable and tapered length
`embodiment, it is about 20 mm long and blow-molded
`wise to provide a desired entry angle (of about 6 de
`from a polyethylene tube in a manner known to those in
`grees) for the side port entry.
`the art.
`Other aspects and advantages of the invention will be
`Details of the preferred embodiment are shown in
`apparent to those of ordinary skill in the art.
`FIGS. 2 and 3 and cross-sections are shown in FIGS.
`4A through 4F. In the preferred embodiment, the cathe
`BRIEF DESCRIPTION OF THE DRAWINGS
`ter body 4 is formed of jacketed spring coil, preferably
`a proximal 20 and distal 22 coil placed end-to-end and
`FIG. 1 is a perspective view of the preferred embodi-
`20 spaced apart so that a linking element (here formed of
`ment of the catheter of the present invention.
`flexible tubes 32) can form the transition region 24
`FIG. 2 is a top plan view, partially cut away, of the
`therebetween. (The spring coils are of a flat wire type
`preferred catheter of the present invention, showing the
`and are made of a biocompatible material such as stain-
`transition zone and side port entry.
`less steel.) The spring coil provides the catheter with
`FIG. 3 is a cross-section,
`taken lengthwise, of the
`preferred catheter of
`the present
`invention,
`taken 25 flexibility while providing axial stiffness.
`lengthwise, showing the balloon,
`the transition zone,
`The coils are jacketed with polyethylene 28 and de
`and the side port entry.
`fme an inflation lumen 30 which passes through the
`FIGS. 4A, 4B, 4C, and 4D, 4E, and 4F are cross-sec-
`proximal coil, the transition region, and the distal coil
`tions of the catheter taken at lines 4A, 4B, 4C, 4D, 4E,
`into balloon 6 so that the fluid can be passed through the
`and 4F, of FIG. 3, respectively.
`30 lumen to inflate the balloon for an angioplasty proce
`FIG. 5 is a cross-section of the transition region and
`dure.
`adjacent shaft,
`taken lengthwise, of another embodi
`A core wire 26 extends through the proximal coil 20
`ment of the present invention.
`into the distal coil 22 and is bonded directly to both at
`FIGS. 6A, 6B, 6C, 6D, 6E and 6F are cross-sections
`points 21. The core wire is also formed of stainless steel
`of the transition region and shaft of the present inven- 35
`and is brazed, welded or soldered to the coil. (Laser
`tion taken at lines 6A, 6B, 6C, 6D, 6E and 6F of FIG. 5.
`welding is preferred.) The bond avoids the necessity of
`FIG. 7 is a cross-section of the transition region and
`melting or otherwise creating a separate lumen for the
`adjacent shaft,
`taken lengthwise, of another embodi
`core wire and imparts stability and stiffness to the cathe
`ment of the present invention.
`ter.
`FIGS. 8A, SB, SC, 8D, SE and SF are cross-sections 40
`The core wire stiffens the catheter in the area where
`of the transition region and shaft, taken at lines SA, SB,
`the guidewire runs exterior to the catheter body, pro
`vides additional axial support, and also forms a safety
`SC, SD, 8E and SF, respectively, of FIG. 7.
`FIG. 9 is a cross section of the transition region and
`wire to anchor the distal coil to the proximal coil. The
`adjacent shaft,
`taken lengthwise, of another embodi
`diameter of the core wire in the preferred embodiment
`ment of the present invention.
`tapers from about 0.016 in. at the proximal end to about
`FIGS. bA, lOB, 1OC, 1OD, and iCE are cross-sec
`0.0 10 in. at the transition region to about 0.0025 in. at its
`tions of the transition region and shaft,
`taken at
`lines
`distal end, but can vary depending on grade of material.
`bA, lOB, bC, lCD, and 1OE of FIG. 9, respectively.
`The transition region 24 is formed in this catheterof
`FIG. ibis a side elevation of apparatus used to create
`a linking element (here flexible tubes 32) which pro
`the side port entry in the transition region of the em- 50
`vides a bridge between the two spring coils forming the
`bodiment of the present catheter shown in FIG. 9.
`catheter body. It serves in this catheter to locate the
`guidewire entry 12 (also referred to as the distal entry
`FIG. 12 is an exploded view of the apparatus of FIG.
`or side port entry). The use of a linking element such as
`11.
`FIGS. 13 and 14 are side elevational views, in cross-
`that described herein to create a three-part catheter
`55 shaft provides great
`flexibility in manufacturing the
`section, of the apparatus of FIG. 11,
`in non-crimping
`catheter; by varying the materials and design of the
`and crimping positions, respectively.
`linking element and the shaft, different catheter charac
`FIG. 15 is a top view in cross-section of the device of
`teristics can be obtained. In the preferred embodiment,
`FIG. 11, showing the variably-positioned holder for the
`catheter.
`the linking element is formed from one or more, prefer-
`60 ably two, parallel flexible tubes 32 which link the infla
`DETAILED DESCRIPTION OF THE SPECIFIC
`tion lumens of the two adjacent coils. (In another em
`EMBODIMENTS
`bodiment described in more detail below, it is formed of
`An angioplasty catheter 1 of the present invention is
`a multilumen insert.)
`shown schematically in FIG. 1. It includes an adapter 2,
`The tubes 32 are formed of a flexible biocompatible
`65 material. The material should be heat resistant and will
`a catheter body 4 defining an inflation lumen 30, and a
`retain its shape during the heating operation. The mate
`balloon 6 disposed at the distal end of the catheter body.
`rial used in the preferred embodiment is a polyimide.
`The balloon is inflated by fluid passing through the
`The advantage of a polyimide is that polyethylene or
`inflation lumen from the proximal end S of the catheter
`
`45
`
`

`

`Page 12 of 14
`
`5,328,472
`
`7
`other materials needed to seal off the remainder of the
`inflation lumen or anchor the flexible tubes in place will
`bond to it. Teflon mt can be used but does not bond
`well without special surface treatment; polyethylene
`may be used but has a lower melting point and will
`require the use of a mandrel during manufacture to
`maintain the patency of the lumen due to its heat sensi
`tivity.
`The flexible tubes must also be large enough to pro
`vide adequate balloon inflation and deflation times 10
`while maintaining a small cross-section. For a catheter
`with a transition region diameter of about 0.43 in., poly
`imide tubes having an outer diameter of 0.0 12 in. and an
`inner diameter of 0.010 in. are preferred.
`The polyimide tubes are anchored in place by a poly
`ethylene plug 34 which also serves to seal
`the coils’
`inflation lumen from the exterior of the catheter at the
`side port entry. The transition zone is preferably about
`1.5 cm. in length and the flexible tubes about 2.0 cm. in
`length.
`The inner lumen 10 is formed of a high density poly
`ethylene tube; in the preferred embodiment, it is about
`0.017 in. in inner diameter and 0.022 in. in outer diame
`ter. It is located within the catheter body and extends 25
`through the balloon to form, at its distal end, the distal
`end of the catheter, 14. It is anchored in place at its
`proximal end by polyethylene plug 34; at its distal end,
`it is sealed to balloon 10 and simultaneously anchored.
`The catheter is made by first welding the core wire to
`the appropriately positioned spring coils. The poly
`imide tubes are sleeved with polyethylene (which will
`ultimately form the polyethylene plug) and positioned
`in the transition zone. The guidewire lumen, containing
`a mandrel tapered at its underside at the proximal end,
`is positioned in the transition region also. The tapered
`mandrel is desirable because it provides a smooth ramp
`at
`the side port entry. An alternate approach to the
`tapered mandrel is to offset the two spring coils slightly
`during manufacture, and use a standard mandrel.
`The polyethylene jacket (which jackets the coil and
`the transition region) is positioned over the catheter and
`heat shrunk in place. The transition region is heated to
`assure that the polyethylene plug has formed and sealed
`the transition region. The guidewire port is cut using
`methods known in the art. The balloon and manifold are
`then attached in a conventional manner.
`Other ways of manufacturing are to form the linking
`element or transition region in advance, preferably by
`molding a multilumen polyethylene unit or element 44
`shown in the catheter of FIGS. 5 and 6a through 6F.
`This catheter also contains two jacketed spring coils 20
`and 22 placed end-to-end and linked by a linking ele
`ment, here in the form of the molded multilumen ele
`ment 44. This multilumen linking element has a crescent
`shaped lumen 4.6 instead of the flexible polyimide tubes
`(for more economical use of space), and includes the
`guidewire lumen 10, although the guidewire lumen 10
`may be formed separately from the multilumen insert
`and bonded to it.
`The multilumen element can be molded of polyimide
`or polyethylene and anchored to the jacketing polyeth
`ylene and the spring coils during the heat shrinking
`operation. Wire (not shown) from the distal end of the
`proximal coil 20 or the proximal end of the distal coil 22 65
`wound helically about the multilumen transition region
`may be added as a safety wire. A disadvantage of poly
`ethylene for the multilumen insert is that mandrels have
`
`8
`to be placed during manufacture in the lumens during
`the heating operation so that they do not collapse.
`Another version of the catheter is shown in FIGS. 7
`and 8A through SF. This embodiment retains the spring
`5 coil 20 and its advantages at the proximal end of the
`catheter, but uses a multilumen extrusion 47 for the
`distal portion. The multilumen extrusion can be formed
`of polyethylene, polyimide or other flexible material,
`and bonded to the proximal
`lumen during the heat
`shrinking operation. The multilumen extrusion is a sin
`gle bilumen extrusion and contains both the guidewire
`lumen 10 and a crescent shaped inflation lumen 48 for
`economical use of space; it is inserted at its proximal end
`into the proximal coil 20 and anchored in a fashion
`15 similar to that described above.
`Although the extrusion in this embodiment is gener
`ally convenient to manufacture, mandrels are necessary
`during the heat shrinking operation to keep the lumens
`open. A disadvantage, of course, is that the distal seg
`20 ment of the catheter lacks the handling characteristics
`of the spring coil, i.e., axial stiffness with flexibility, and
`that it is very difficult to bond a core wire to the extru
`sion, further reducing the stability and axial stiffness of
`the catheter. This drawback can be overcome, how
`ever, by reinforcing the extrusion with a braid or fibers.
`For example,
`fibers in an extrudable matrix such as
`Vectra m made by Hoechst Celanese might be suitable
`for this extrusion (and, indeed, the proximal segment of
`30 this or. the other embodiments of the catheter as well).
`In yet another embodiment of the present invention,
`shown in FIGS. 9 and 1OA through 1OF, the entire
`catheter shaft is made of one spring coil 50. The side
`port entry 12 in the transition region is formed by first
`~ connecting adjacent coils together in what will be the
`transition zone 24. Connecting adjacent coils together
`helps to hold the spring coil steady during crimping;
`brazing or another high temperature treatment is pre
`ferred over welding because it makes the coils more
`~ ductile and therefore more amenable to shaping. Addi
`tional strength can be obtained by laser welding each
`adjacent coil to the core wire as well.
`The group of adjacent connected coils in zone 24 are
`then carefully crimped using a crimping tool such as a
`~ machinist’s scribe or the specially designed tool of
`FIGS. 11 through 15. The crimping is controlled to
`provide a gradual, smooth transition into the spring coil
`shaft, while retaining the inflation lumen. As shown in
`FIG. 9, the desired entry angle 71 is about 6 degrees,
`~o and the entry can be hand-crimped to provide the de
`sired angle, or a device such as that shown in FIG. 11
`can be used to easily create the crimping angle.
`To maintain the inflation lumen during crimping, a
`core wire, (preferably two of about 0.0 14” in diameter)
`~ is placed in the lumen during the crimping. In the pre
`ferred embodiment, a hypotube mandrel split length
`wise to form a crescent or U, is inserted during crimp
`ing to maintain and shape the inflation lumen.
`After crimping, one or more, preferably two, short
`60 flexible tubes, specifically polyimide shafts 32 such as
`those described earlier, are inserted by mandrel into the
`inflation lumen in the transition zone to transport infla
`tion fluid between the distal and proximal portion of the
`spring coil shaft. A seal, preferably of a polymer such as
`polyethylene, or an adhesive such as a cyanoacrylate, a
`UV-cured adhesive, or an epoxy, is then inserted to seal
`the polyimide shafts in place and block the remainder of
`the inflation lumen from fluid flow.
`
`

`

`Page 13 of 14
`
`5,328,472
`
`10
`
`15
`
`9
`The guidewire lumen itself is then inserted and fixed
`to the side port entry, and the remainder of the catheter
`is finished.
`In the preferred version of this embodiment of the
`invention, the spring coil Outer diameter is about 0.034 5
`in., the length of crimp is about 0.200 in. (200mm), and
`the angle 71 of taper is 6 degrees.
`The crimping apparatus 51 illustrated in FIGS. 11
`through 15 is a prototype designed to crimp spring coils
`of various sizes. As shown in particular i