United States Patent (19)
`Enger
`
`54 RAPIDLY EXCHANGEABLE CORONARY
`CATHETER
`
`75 Inventor: Christine D. Enger, Tenafly, N.J.
`73 Assignee: Arterial Vascular Engineering, Inc.,
`Santa Rosa, Calif.
`
`21 Appl. No.: 08/095,036
`22 Filed:
`Jul. 20, 1993
`Related U.S. Application Data
`63 Continuation of application No. 07/999,589, Dec. 30, 1992,
`abandoned, which is a continuation of application No.
`07/759,107, Sep. 6, 1991, abandoned, which is a continua
`tion of application No. 07/618,531, Nov. 26, 1990, aban
`doned, which is a continuation of application No. 07/303,
`803, Jan. 30, 1989, abandoned.
`(51) Int. Cl." .................................................... A61M 29/00
`52 U.S. Cl. ............................. 604/102; 604/96; 606/194
`58 Field of Search ................................ 604/96-103, 51,
`604/54, 164, 171; 606/192, 194
`
`56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`871,474 11/1907 Buckner .................................. 604/102
`2,024.301 12/1935 Norwood ................................ 128/344
`(List continued on next page.)
`FOREIGN PATENT DOCUMENTS
`0274129A2 7/1988 European Pat. Off..
`O397357 11/1990 European Pat. Off..
`2340078 10/1977 France.
`WO 8603129 6/1986 WIPO.
`WO 8803422 5/1988 WIPO.
`
`OTHER PUBLICATIONS
`Werns, “Review of Hardware for PTCA”, Journal of Inter
`ventional Cardiology, vol. 1, No, 3, 1988, pp. 209-219.
`Thomas et al., “Efficacy of a New Angioplasty Catheter for
`Severely Narrowed Coronary Lesions”, Journal of the
`American College of Cardiology, vol. 12, pp. 694-702.
`
`
`
`USOO5980486A
`Patent Number:
`11
`(45) Date of Patent:
`
`5,980,486
`Nov. 9, 1999
`
`Meier, “Coronary Angioplasty”, 1987, pp. 13-15.
`Myler et al., “The Balloon on a Wire Device: A New
`Ultra-Low-Profile Coronary Angioplasty System/Con
`cept, Catheterisation and Cardiovascular Diagnosis, Vol.
`14, 1988, pp. 135-140.
`Brochure for Bard “Probe" PTCA Dilatation System, 1987.
`Brochure for SciMed “Ace” fixed-wire PTCA catheter, Dec.
`1988.
`
`(List continued on next page.)
`
`Primary Examiner-Corrine McDermott
`Attorney, Agent, or Firm-Richard L. Klein, Esq.
`57
`ABSTRACT
`A rapidly exchangeable catheter for use in the coronary
`arteries includes an elongate relatively Stiff proximal Seg
`ment that defines an inflation lumen, an intermediate, shorter
`Segment formed from a more flexible plastic material and
`having two lumens, and a third, Single lumen distal Segment.
`A balloon or other instrumentality adapted to operate in a
`coronary artery is mounted to the distal region of the
`catheter. The intermediate and distal Segments include a
`guidewire lumen by which the catheter may be advanced
`along a guidewire. The proximal Segment may include an
`inflation lumen when the operating instrumentality at the
`distal end of the catheter is a balloon. The intermediate and
`distal Segments of the catheter are of a length of between
`about 35 to 45 cm Such that when the catheter is advanced
`into the most remote distal portions of the coronary anatomy,
`the flexible plastic intermediate and distal Segments will
`extend over the aortic arch of the patient thereby containing
`the guidewire over the aortic arch and maintaining the
`juncture of the relatively Stiff proximal Segment and the
`more flexible intermediate Segment proximally of the aortic
`arch. The relatively stiff proximal section thus extends
`generally along a Straight line from the femoral artery into
`the descending aorta but not So far as into the aortic arch.
`Buckling of the catheter is avoided So that the catheter is
`more easily manipulated.
`
`28 Claims, 3 Drawing Sheets
`
`Page 1
`
`Medtronic Exhibit 1050
`
`

`

`5,980,486
`Page 2
`
`U.S. PATENT DOCUMENTS
`2.930,377 3/1960 Cowley.
`3,769,981 11/1973 McWhortes ............................... 604/96
`4,055,682 10/1977 Merrill .......
`... 427/2
`4,173,981 11/1979 Mortenson .....
`... 604/282
`4,195,637 4/1980 Grintzog et al.
`... 128/348
`4.328,806
`5/1982 Coopes ...................................... 604/99
`4,402,307 9/1983 Hanson et al..
`4,490,421 12/1984 Levy.
`4,545,390 10/1985 Leary.
`4,581,017 4/1986 Sahota ..................................... 604/101
`4,616,652 10/1986 Simpson ...
`128/344
`4,616,653 10/1986 Samson et al..
`604/53
`4,652,258 3/1987 Drach .........
`... 604/96
`4,655,748 4/1987 Mushika ........
`... 128/344
`4,748,982 6/1988 Horzewski et al.
`... 128/344
`4,762,129 8/1988 Bojzel ...............
`... 128/344
`4,771,777 9/1988 Horzewski et al.
`... 604/280
`4,775,371 10/1988 Mueller, Jr. ...
`4,798,193
`1/1989 Giesy et al. ................................ 128/7
`4,813,930 3/1989 Elliot ...
`604/53
`4,820.271
`4/1989 Deutsch .....
`604/99
`4,824,435 4/1989 Giesy et al. ...
`... 604/49
`4,827,941
`5/1989 Taylor et al. ........................... 128/657
`
`
`
`4,846,174 7/1989 Willard et al. .......................... 128/344
`4,877,031 10/1989 Conway et al. ........................ 606/194
`4,892.519
`1/1990 Songer et al..
`4,943.278 7/1990 Euteneuer et al..
`4,988,356
`1/1991 Crittenden.
`4,998,923 3/1991 Samson et al. ......................... 606/194
`5,024,234 6/1991 Leary et al. .
`5,040,548 8/1991 Yock.
`5,046,503 9/1991 Schneiderman.
`5,061,273 10/1991 Yock.
`5,102,403 4/1992 Alt.
`5,154,725 10/1992 Leopold.
`
`OTHER PUBLICATIONS
`Catalogue for Schneider-Shiley Monorail Bonzel Coronary
`Dilatation System, Oct. 1988.
`Brochure for Schneider MonorailTM-Plccolino catheter, Oct.
`1988.
`Finci et al., “Clinical Experience with the Monorail Balloon
`Catheter for C
`Angioplastv’. Catheterisati
`d
`atneter Ior coronary Angioplasty taineerisation an
`Cardiovascular Diagnosis, vol. 14, 1988 pp. 206-212.
`Brochure for ACS HartzlerTM LPSC) Dilatation catheter,
`1985.
`
`Page 2
`
`Medtronic Exhibit 1050
`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 1 of 3
`
`5,980,486
`
`
`
`Page 3
`
`Medtronic Exhibit 1050
`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 2 of 3
`
`5,980,486
`
`
`
`Page 4
`
`Medtronic Exhibit 1050
`
`

`

`U.S. Patent
`
`Nov. 9, 1999
`
`Sheet 3 of 3
`
`5,980,486
`
`
`
`
`
`
`
`
`
`*********************=========~==+==~::~~====~~~
`
`Page 5
`
`Medtronic Exhibit 1050
`
`

`

`5,980,486
`
`1
`RAPIDLY EXCHANGEABLE CORONARY
`CATHETER
`
`This application is a continuation of Ser. No. 07/999,589,
`filed Dec. 30, 1992, now abandoned, which is a continuation
`of Ser. No. 07/759,107, filed Sep. 6, 1991, now abandoned,
`which is a continuation of Ser. No. 07/618,531 filed Nov. 26,
`1990, now abandoned, which in turn is a continuation of Ser.
`No. 07/303,803, filed Jan. 1, 1989, which is also now
`abandoned.
`
`2
`the proximal end of the guidewire thereby effectively
`extending the length of the guidewire that protrudes out of
`a patient sufficiently to permit the catheter to be withdrawn
`and a new catheter to be threaded back into the patient
`without losing guidewire position.
`Still another technique for performing a catheter eXchange
`is that described in “New Instruments for Catheterization
`and Angiocardiography’ by Bjorn Nordenstrom, Radiology,
`Vol. 85, 1965, pp. 256-259, which describes a catheter
`having a relatively short guidewire lumen at the distal end of
`the catheter, the guidewire lumen having a proximal termi
`nal opening located distally of the proximal end of the
`catheter shaft. In this arrangement, the guidewire passes
`through the catheter Shaft only for a Segment of the length
`of the Shaft. The catheter can be moved along the guidewire
`in the fashion of a “monorail”. Because the guidewire lumen
`is relatively short and is considerably shorter than the overall
`length of the catheter, the catheter can be withdrawn from
`the patient over the original guidewire without dragging the
`guidewire out of the artery together with the catheter
`because the length of guidewire protruding from the patient
`is longer than the length of the guidewire lumen of the
`catheter. Thus, a portion of the guidewire is exposed at all
`times and may be grasped by the physician. Such a monorail
`system has recently been incorporated into PTCA catheters
`as illustrated, for example, in U.S. Pat. Nos. 4,762,129
`(Bonzel) and 4,748,982 (Horzewski).
`Although the use of the monorail System facilitates cath
`eter exchanges, the PTCA catheters in which the monorail
`System have been incorporated have presented Some diffi
`culties. One of the problems presented is that because the
`guidewire only extends through a relatively Small portion of
`the overall length of the catheter, the remaining portion of
`the catheter shaft is unsupported by the guidewire. When the
`balloon catheter and guidewire are advanced through the
`guide catheter by pushing the catheter Shaft, the unsupported
`portion of the catheter shaft tends to buckle within the guide
`catheter. Buckling of the catheter Shaft within the guide
`catheter increases the number and area of points of contact
`between the catheter Shaft and the inner Surface of the guide
`catheter lumen, thus increasing friction and causing the
`balloon catheter to bind up in the guide catheter and impair
`ing the ability of the catheter to be pushed along the
`guidewire. The tendency to become bound up in the guide
`catheter increases with the extent to which the catheter is
`advanced through the guide catheter and prevents the cath
`eter from being advanced into distal coronary vasculature.
`The tendency for the dilatation catheter shaft to buckle is
`particularly acute in the region of the aortic arch.
`It is among the general objects of the invention to provide
`an improved PTCA catheter having a rapid exchange feature
`which avoids the foregoing and other difficulties.
`
`15
`
`40
`
`45
`
`50
`
`25
`
`FIELD OF THE INVENTION
`This invention relates to balloon dilatation catheters and
`particularly to Such catheters as are used in percutaneous
`transluminal coronary angioplasty.
`BACKGROUND OF THE INVENTION
`Dilatation catheters, and particularly, those used for per
`cutaneous transluminal coronary angioplasty (PTCA), typi
`cally include an elongate flexible shaft of the order of 150
`cm long having a dilatation balloon mounted to the distal
`end of the Shaft and an inflation lumen extending longitu
`dinally within the shaft from its proximal end to the interior
`of the balloon so that the balloon may be inflated and
`deflated. Typically, such PTCA catheters also are provided
`with a full length guidewire lumen that is open at the distal
`tip of the shaft at a distal outlet opening. The proximal end
`of the guidewire lumen is open at the proximal end of the
`catheter. The guidewire lumen receives a guidewire which,
`when the guidewire and catheter are placed within a
`patient's artery, can be manipulated to guide the wire and
`catheter to the desired branch of the patient's arteries.
`Typically, the balloon dilatation catheter and guidewire
`are guided to the entrance to the coronary arteries by a
`previously placed guide catheter. The guide catheter com
`35
`monly is percutaneously inserted into the patient's femoral
`artery and is advanced along the aorta toward the heart. The
`guide catheter typically is provided with a preshaped distal
`tip adapted to remain at the coronary ostium leading to the
`coronary artery. Once placed, the guide catheter provides
`direct, quick access to the entrance to the coronary arteries.
`It is common during a PTCA procedure for the physician
`to exchange the balloon catheter for another catheter, for
`example, if it is desired to change balloon sizes. This may
`occur, for example, if the physician initially performed a
`partial dilatation with a Small diameter balloon and then
`wished to further dilate the patient's artery by using a
`catheter having a larger balloon. Such a catheter eXchange
`may be accomplished in Several ways. In one technique, the
`conventional guidewire which may be approximately 175
`cm long is removed from the in Situ balloon catheter and is
`replaced with a longer eXchange wire, typically about 300
`cm long. The length of the eXchange wire that extends out
`of the patient is greater than the length of the balloon
`catheter thus providing a means by which the guidewire may
`be grasped at all times to prevent inadvertent withdrawal of
`the guidewire as the catheter is withdrawn. Once the catheter
`is withdrawn over the exchange wire, the next catheter can
`be threaded over the exchange wire and inserted into the
`patient, the exchange wire providing a direct path to guide
`the catheter to the portion of the artery to be dilated. If
`desired, the exchange wire then may be removed and
`replaced with a shorter conventional wire, although Some
`physicians may prefer to permit the eXchange wire to remain
`in place for the remainder of the procedure.
`Another technique omits the necessity for an exchange
`wire by providing a guidewire extension that is attached to
`
`55
`
`60
`
`65
`
`SUMMARY OF THE INVENTION
`The catheter of the present invention is formed from a
`composite shaft that includes an elongate proximal Segment
`formed from a relatively stiff metal tube and defining an
`inflation lumen, an intermediate, shorter Segment formed
`from a more flexible, plastic material and having two
`lumens, and a third Single lumen distal Segment. The inter
`mediate Segment includes an inflation lumen that is a
`continuation of the inflation lumen of the proximal Segment
`and a Second, parallel guidewire lumen. The third, distal
`tubular Segment is formed from flexible plastic material and
`has a Single lumen which is a continuation of the guidewire
`lumen in the intermediate Segment and opens at a distal
`
`Page 6
`
`Medtronic Exhibit 1050
`
`

`

`3
`outlet tip. The dilatation balloon is mounted on the distal end
`of the catheter with its proximal end mounted to the inter
`mediate Segment and its distal end mounted to the distal
`Segment. The guidewire lumen has a proximal opening
`proximally of the balloon and communicates with the lumen
`of the distal Segment and distal outlet opening distally of the
`balloon.
`The intermediate and distal Segments are of a combined
`length, between about 35 cm to 45 cm, such that with the
`catheter advanced into the most remote distal portions of the
`coronary anatomy, the flexible plastic intermediate Segment
`will extend over the aortic arch of the patient. The juncture
`of the relatively stiff proximal segment and the more flexible
`intermediate Segment thus remains proximally of the aortic
`arch So that the relatively Stiff elongate proximal Section
`extends generally along a Straight line from the femoral
`artery into the descending aorta, but not So far as into the
`aortic arch. The moderately flexible proximal Segment is
`Sufficiently Stiff and is Self-Supporting So that it will not
`buckle in the guide catheter as the catheter is pushed in a
`distal direction. Additionally, the intermediate and distal
`Segments of the catheter are fully Supported by the
`guidewire that extends through the guidewire lumen and
`thereby provides Substantial Support for the intermediate and
`distal Segments of the catheter. The catheter construction
`does not tend to bind up within the guide catheter and
`thereby facilitates advancement of the distal balloon end of
`the catheter into more distal regions of a patient's coronary
`anatomy. Moreover, because the cross-section of the metal
`tubular proximal Segment is relatively Small, it presents
`reduced obstruction through the guide catheter to a flow of
`radiopaque contrast liquid and, thereby, makes it easier for
`the physician to inject contrast liquid into the patients
`coronary arteries in order to visualize them fluoroscopically.
`It is among the general objects of the invention to provide
`an improved rapidly exchangeable balloon dilatation cath
`eter.
`Another object of the invention is to provide a rapidly
`eXchangeable balloon dilatation catheter which is provided
`with axial Support along the full length of the catheter.
`Another object of the invention is to provide a rapidly
`eXchangeable catheter having a relatively flexible distal
`portion that receives a guidewire and is of Sufficient length
`that it can extend from the distal coronary anatomy over the
`aortic arch and into the descending aorta.
`A further object of the invention is to provide a rapidly
`eXchangeable catheter having an elongate moderately flex
`ible Self-Supporting proximal Section and at least one distal
`Section that is more flexible and has a guidewire lumen
`extending therethrough whereby the guidewire may Support
`Said distal Segments.
`A further object of the invention is to provide a rapidly
`eXchangeable catheter which has a reduced tendency to
`buckle within the guide catheter.
`Another object of the invention is to provide a rapidly
`eXchangeable catheter which provides reduced friction in the
`guide catheter.
`A further object of the invention is to provide a rapidly
`eXchangeable catheter which better enables the physician to
`advance the distal end of the catheter into the distal coronary
`anatomy of a patient.
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`DESCRIPTION OF THE DRAWINGS
`The foregoing and other objects and advantages of the
`invention will be appreciated more fully from the following
`
`65
`
`5,980,486
`
`4
`further description thereof, with reference to the accompa
`nying drawings wherein:
`FIG. 1 is a fragmented illustration of the catheter;
`FIG. 2 is an enlarged illustration of the catheter;
`FIG. 3 is a diagrammatic illustration of a patient showing
`the manner in which a balloon catheter is advanced from the
`femoral artery through the aorta to the patient's heart;
`FIG. 4 is an illustration of the aorta leading from the heart
`and coronary arteries with a guide catheter in place and the
`catheter of the present invention extending through the guide
`catheter;
`FIG. 5 is a cross-sectional illustration of the two lumen
`Segment of the intermediate Segment of the catheter as Seen
`along the line 5-5 of FIG. 2;
`FIG. 6 is an enlarged illustration of the proximal end of
`the balloon and its point of attachment to the intermediate
`Segment,
`FIG. 7 is a sectional longitudinal illustration of the
`catheter in the region where the proximal metal tubular
`Segment is joined to the intermediate more flexible plastic
`Segment; and
`FIG. 8 is an enlarged longitudinal sectional illustration of
`the distal end of the catheter showing the balloon and the
`manner of its attachment to the intermediate and distal
`Segments.
`DESCRIPTION OF THE ILLUSTRATIVE
`EMBODIMENT
`FIG. 3 illustrates, diagrammatically, a conventional over
`the-wire balloon dilatation catheter 10 and a guidewire 12
`inserted into the patient's vasculature through a guide cath
`eter 14. The guide catheter 14 is initially placed,
`percutaneously, into the patient's femoral artery 16 and is
`advanced along the descending aorta 18 over the aortic arch
`20 and into the ascending aorta 22 that leads from the heart
`24. As will be appreciated by those skilled in the art, the
`distal end of the guide catheter is Specially shaped So that the
`distal tip 23 of the guide catheter will easily lodge in the
`entrance to the right 25 or left 27 coronary artery (see FIG.
`4).
`When it is desired to exchange the balloon catheter 10 for
`another, it is important that the guidewire 12 be maintained
`within the patient's artery So that it may guide the next
`Succeeding catheter quickly and efficiently to the intended
`Site in the patient's vascular System. Typically, the clear
`ances between the guidewire 12 and the inner lumen of the
`catheter 10, coupled with the bends which the catheter 10
`and guidewire 12 must follow along the patient's artery are
`such that withdrawal of the catheter 10 tends to drag the
`guidewire 12 out with the catheter 10. In order to maintain
`the guidewire 12 in place while the catheter 10 is withdrawn,
`it is necessary to hold the guidewire 12 by its proximal end
`while withdrawing the catheter 10 over the guidewire 12.
`Among the techniques for facilitating a catheter exchange
`is the use of a monorail-type of catheter in which the
`guidewire lumen in the catheter extends only over a rela
`tively short length of the catheter at the distal end of the
`catheter. Because the guidewire lumen is shorter than the
`portion of the guidewire that protrudes out of the patient,
`Some part of the guidewire is always exposed and may be
`grasped to maintain guidewire position. With the monorail
`System, it is unnecessary to use exchange wires or other
`devices to increase the effective length of the guidewire in
`order to perform a catheter exchange.
`FIG. 2 is a fragmented illustration of a catheter in accor
`dance with the invention. The catheter 26 includes an
`
`Page 7
`
`Medtronic Exhibit 1050
`
`

`

`S
`elongate proximal Segment 28 which is formed from metal
`lic hypodermic tubing, preferably StainleSS Steel. The proxi
`mal segment may be of the order of 100 to 110 cm long. The
`tubing 28 may be of the order of 0.022" outer diameter with
`a wall thickness of about 0.003". The catheter 26 also
`includes an intermediate Segment 30 attached at its proximal
`end to the distal end of the metal tube 28 and being shorter
`in length than the metal tube 28. The catheter also includes
`a distal segment 32 (FIGS. 2 and 8) attached to the distal end
`of the intermediate segment 30. A dilatation balloon 34 is
`mounted on the distal segment 32 as will be described. The
`metallic tubular proximal segment 28 defines a lumen 36
`(FIG. 7) that extends fully through its length. A luer fitting
`38 is attached to the proximal end of the tubing 28 to connect
`the lumen 36 with an inflation/deflation device, Such as a
`Syringe (not shown). The lumen 36 communicates with a
`lumen 40 (FIG. 8) in the intermediate segment 30. The
`lumen 40 terminates at a port 42 disposed within the balloon
`34. Thus, the balloon 34 may be inflated and deflated
`through the inflation/deflation lumens 36, 40 in the metal
`tube 28 and intermediate segment 30, respectively.
`As will be described, the metal tubular segment 28
`provides for a high degree of column Strength and enables
`the catheter to be pushed from its proximal end without
`buckling. The metal tube 28 may be coated with a thin film
`of lubricious material, Such as Teflon, polytetrafluoroethyl
`CC.
`The flexible plastic intermediate segment 30 may be an
`extruded tube of Suitable plastic Such as high density poly
`ethylene. The intermediate segment 30 may be of the order
`of 0.045 inches outer diameter. The length of the interme
`diate segment 30 is between about 30 to 40 cm for reasons
`discussed below. The intermediate segment 30 has two
`lumens including the inflation lumen 40 which may be
`somewhat D-shaped as illustrated in FIG. 5. The other lumen
`44 may be circular as shown in FIG. 5 and is adapted to
`receive the guidewire 12. The guidewire lumen 44 may be
`of the order of 0.020 inches diameter. The guidewire lumen
`terminates in a proximal opening 46 So that the guidewire is
`exposed proximally of the intermediate Segment 30. Thus,
`the guidewire may extend within the guide catheter 14 in
`parallel to and outside of the proximal Segment 28.
`The distal segment 32 of the catheter is formed from a
`Separate length of Single lumen tubing which may be
`extruded from a relatively flexible plastic material Such as
`low density polyethylene. The distal Segment 32 is circular
`in cross-section and has a circular lumen 48, FIG. 6, which
`is an extension of the guidewire lumen 44 in the intermediate
`segment 30. The distal tip of the distal segment 32 is open
`at a distal outlet orifice 33, FIG. 8. The distal segment 32
`may be attached by fusing its proximal end to the distal end
`of the intermediate Segment 30 while maintaining continu
`ation of the guidewire lumen 44, 48 and the opening 42 of
`the inflation lumen 40 by inserting mandrels in those lumens
`during the fusion process. A highly radiopaque marker band
`preferably is mounted on the distal Segment 32 and is
`encapsulated in an overlying thin polyethylene sleeve 37,
`the sleeve 37 extending proximally over the joint 39
`between the intermediate segment 30 and distal segment 32.
`The sleeve 37 also is heat fused to the shaft. The distal
`segment 32 may have a wall thickness of the order of 0.0035
`inches thereby making it more flexible than the more mas
`sive intermediate segment 30. A radiopaque marker band 35
`formed from an appropriate radiopaque material, Such as
`gold or platinum, may be mounted on the distal Segment 32.
`The balloon 34 is mounted on the distal region of the
`catheter. The balloon 34 may be formed from a suitably
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`5,980,486
`
`6
`flexible Strong and relatively inelastic material Such as
`polyethylene terephthalate. The balloon may be formed in a
`procedure described in U.S. Pat. No. 4,490,421 to Levy. The
`balloon may be of the order of 20 mm long and may have
`a balloon diameter when inflated of from about 1.5 mm to
`4.0 mm. The wall thickness may be of the order of 0.0005"
`to 0.001". The balloon includes an elongate cylindrical
`portion having integral tapering conical Sections 49, 51 at
`each of its proximal and distal ends. Each of the conical
`Sections merges into a Small diameter cylindrical neck, the
`neck 52 at the proximal end of the balloon being larger in
`diameter than the neck 54 at the distal end. The proximal
`neck 52 is mounted on the distal region of the intermediate
`segment 30 and the distal neck 54 is mounted on the distal
`portion of the distal segment 32. The neck portions 52, 54
`are Securely bonded to the intermediate and distal Segments
`30, 32, respectively, by an appropriate adhesive Such as an
`epOXy.
`The manner in which the catheter of the present invention
`is used will be appreciated from FIGS. 3 and 4. In a typical
`procedure, the femoral artery 16 is accessed percutaneously
`by a hollow needle. After inserting the needle into the
`femoral artery, a relatively large diameter guidewire (about
`0.038" diameter) is advanced through the needle and into the
`femoral artery. The needle is removed and an introducer
`sheath and dilator are placed inside the artery. The dilator is
`then removed. The guide catheter is inserted over the
`guidewire and is advanced along with the guidewire to the
`ascending aorta when the 0.038" guidewire is removed. The
`distal end of the guide catheter 14 is shaped specially to be
`easily inserted into the entrance of one of the two coronary
`Ostia to access either the right or left main coronary arteries.
`FIG. 4 illustrates a guide catheter 14 seated in the left
`coronary ostium. Once the guide catheter is in place, the
`0.038" guidewire may be removed. The guide catheter 14
`then is ready to receive the dilatation catheter and its Small
`diameter (e.g., 0.010"-0.018" diameter) guidewire.
`In placing the Small diameter Steerable guidewire 12 and
`the conventional over-the-wire balloon dilatation catheter
`10, it is conventional practice to first assemble the guidewire
`12 with the balloon catheter 10 and then pass them both in
`unison through the guide catheter. Alternately, with the
`present invention, the guidewire 12 may be inserted through
`the guide catheter by itself. The guidewire is advanced to the
`coronary ostium and then may be further advanced into the
`coronary arteries. The guidewire may be of the type
`described in U.S. Pat. No. 4,545,390 to Leary and may be
`Steerable So that it can be manipulated and guided to the
`desired branch of the coronary arteries to be treated. The
`progreSS of the guidewire through the patient's coronary
`arteries may be monitored fluoroscopically by the physician.
`The physician also may inject radiopaque contrast liquid
`through the guide catheter to visualize the coronary anatomy
`on the fluoroscope. Once the guidewire 12 has been
`advanced through the Stenosis to be treated, the balloon
`catheter 26 of the present invention is advanced over the
`guidewire 12 and within the guide catheter 14. The catheter
`26 will track Smoothly and easily along the guidewire with
`no significant tendency to buckle. This results from the
`relatively Stiff, pushable nature of the elongate metal tubular
`proximal Segment 28 of the catheter. Additionally, the inter
`mediate and distal segments 30, 32 are supported by the
`guidewire 12 which provides significant resistance to buck
`ling of the intermediate and distal segments 30, 32. It will be
`appreciated, therefore, that when the catheter 26 is advanced
`over the guidewire, the catheter will have significant axial,
`column Support fully along its length. In this regard, it is
`
`Page 8
`
`Medtronic Exhibit 1050
`
`

`

`7
`important to note that the proximal end of the guidewire
`lumen 44 in the intermediate segment 30 overlaps
`longitudinally, the distal end of the metal tubular proximal
`segment 28 that is embedded in the proximal end of the
`intermediate segment 30. Thus, when the catheter is
`advanced over the guidewire 12, there is column Support
`fully along the length of the catheter, from its proximal to its
`distal end. As a result, there is considerably reduced ten
`dency for any portion of the catheter to buckle longitudi
`nally. Consequently, the friction between the balloon dila
`tation catheter 26 and the guide catheter 14 is Substantially
`reduced thereby enabling the distal end of the catheter to be
`advanced into distal, remote and tortuous regions of the
`patient's coronary anatomy.
`In order to better grasp the proximal end of the catheter to
`push it through the guide catheter, a gripping device 56 may
`be mounted on the proximal Segment 28. The gripping
`device 56 includes a nut 58 which is threaded into a tubular
`collet 60. The collet 60 and nut 58 are screwed together over
`the proximal segment 28 to cause the collet 60 to securely
`grip the proximal Segment 28. The position of the gripping
`device 56 may be adjusted by loosening the nut and repo
`Sitioning the device.
`It should be noted that the length of the intermediate and
`distal segments 30, 32 are selected so that when the balloon
`is placed in a very distal region of the coronary anatomy, the
`juncture of the proximal end of the intermediate Segment
`with the proximal tubular segment 28 is disposed in the
`descending aorta 18 and does not extend into the aortic arch
`20. Thus, the combined length of the intermediate and distal
`segments 30, 32 should be between 35 to 45 cm long, with
`a length of 40 cm being preferred for most patients anato
`mies. It will be appreciated from the foregoing construction
`that the flexible intermediate and distal portions 30, 32 will
`pass easily through the curve of the aortic arch 20 without
`tendency to buckle because they are fully Supported by the
`guidewire 12. The relatively Stiff elongate metal proximal
`Segment 28 does not pass through the aortic arch 20 and
`maintains its relatively Straight configuration So that its
`pushable characteristics are not compromised. There is
`minimal tendency of the catheter to dislodge the distal tip of
`the guide catheter from its position in the coronary ostium.
`Should it be desired to exchange the balloon catheter 26
`for another catheter, there is no need to use an extended
`length guidewire. Typically, about 50 cm of the guidewire 12
`will protrude exterioraly of the patient. When the catheter 26
`is withdrawn, a Segment of the guidewire 12 will be exposed
`at all times, thereby enabling the guidewire 12 to be grasped
`to maintain its position in the patient. Thus, the catheter 26
`may be withdrawn without dragging the guidewire 12 out of
`position. After the first catheter has been removed, another
`catheter may be threaded onto the guidewire and advanced
`through the guide catheter and into the coronary anatomy,
`guided by the guidewire 12. The catheter constructed in
`accordance with the invention will be advanced easily,
`without tendency to buckle or develop high friction within
`the guide catheter and with no significant tendency to
`dislodge the guide catheter from its position at the coronary
`ostium.
`From the foregoing, it will be appreciated that the inven
`tion provides an improved rapidly exchangeable catheter
`construction and catheterization method.
`It should be understood, however, that the foregoing
`description of the invention is intended merely to be illus
`trative thereof and that other modifications and embodi
`ments may be apparent to those skilled in the art without
`departing from its Spirit.
`
`1O
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`5,980,486
`
`8
`For example, although the invention has been illustrated
`in connection with a balloon dilatation catheter, it may also
`be incorporated in other types of catheters, Such as laser
`catheters, hot tip catheters, infusion catheters, ar