United States Patent
`Osborn
`
`119)
`
`[54] APPARATUS FOR UNIFORMLY
`IMPLANTINGA STENT
`
`[75]
`
`Inventor: Kenneth L. Osborn, Mountain View,
`Calif.
`
`[73] Assignee: Advanced Cardiovascular Systems,
`Inc., Santa Clara, Calif.
`
`[21] Appl. No.: 111,173
`
`[22] Filed:
`
`Aug. 24, 1993
`
`[SL] Unt, C16 ne ceetsencnereseeseenseres A61M 29/02
`[52] US. Ch. cee eee ceeseeenecsneeeees 606/108; 606/194;
`604/101
`[58] Field of Search............... 606/108, 194, 195, 192,
`606/198; 604/96, 101, 103
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`~
`
`4,327,736 5/1982 WOVE .escscscssessesresesesecsersneees 604/101
`4,733,665
`3/1988 Palmaz .
`4,739,762 4/1988 Palmaz .
`4,776,337 10/1988 Palmaz .
`4,856,516
`8/1989 Hillstead .
`4,913,141 4/1990 Hillstead .
`4,950,227 8/1990 Savin et al.
`5,019,085
`5/1991 Hillstead .
`5,064,435 11/1991 Porter .
`
`.
`
`US005409495A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,409,495
`Apr. 25, 1995
`
`5,102,417 4/1992 Palmaz .
`5,108,416 4/1992 Ryanetal. .
`5,116,318
`5/1992 Hillstead .
`5,122,154 6/1992 Rhodes .
`5,133,732 7/1992 Wiktor .
`5,147,377 9/1992 Sahota...eeeecseeseseeeessee 606/194
`5,226,889 7/1993 Sheiban .
`5,226,913
`7/1993 Pinchuk .
`5,242,452 9/1993 Inoue .
`
`Primary Examiner—Michael H. Thaler
`Attorney, Agent, or Firm—Fulwider Patton Lee &
`Utecht
`
`[57]
`ABSTRACT
`An improved system for uniformly implanting a stent in
`a body lumen comprising an intravascular catheter hav-
`ing an elongated catheter bodyandat least one inflation
`lumen contained therein, the catheter body including
`proximal and distal ends, a balloon near the distal end of
`the catheter for expanding the stent, an elastic sleeve
`surrounding andin contact with the balloon for control-
`ling the radial expansion of the balloon and either re-
`straining bands or a pair of control balloons to control
`the expansion of the balloon so that controllable expan-
`sion characteristics of the stent are achieved.
`
`_ 15 Claims, 3 Drawing Sheets
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 1
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 1
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`U.S. Patent
`
`Apr. 25, 1995
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`Sheet 1 of 3
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`5,409,495
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 2
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 2
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`Sheet 2 of 3
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`5,409,495
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`U.S. Patent
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`Apr. 25, 1995
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 3
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 3
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`Apr. 25, 1995
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`Sheet 3 of 3
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`5,409,495
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`U.S. Patent
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 4
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 4
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`1
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`5,409,495
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`APPARATUS FOR UNIFORMLY IMPLANTING A
`STENT
`
`BACKGROUNDOF THE INVENTION
`
`_
`1. Field of the Invention
`This invention relates generally to improvements in
`methods and apparatus for uniformly implanting a stent
`and, more particularly, to improved uniform stent im-
`plantation systems wherein radial expansion is con-
`trolled.
`2. Description of Related Art
`In typical percutaneous transluminal coronary angio-
`plasty (PTCA)procedures, a guiding catheter is percu-
`taneously introduced into the cardiovascular system of
`a patient through the brachial or femoral arteries and
`advanced through the patient’s vasculature until the
`distal end of the guiding catheteris in the ostium of the
`desired coronary artery. A guidewire and a dilatation
`catheter having a balloon on the distal end ofthe dilata-
`tion catheter are introduced through the guiding cathe-
`ter with the guidewire sliding within the dilatation cath-
`eter. First, the guidewire is passed through the guiding
`catheter and into the patient’s coronary vasculature.
`Second, the dilatation catheter is’ advanced over the
`previously passed guidewire until the dilatation balloon
`is properly positioned across a lesion. Once in position
`across the lesion, a preformed balloon carried by the
`catheteris inflated to a predetermined size with a liquid
`at relatively high pressures (e.g., greater than about 4
`atmospheres) to radially compress the atherosclerotic
`plaque ofthe lesion against the inside of the artery wall
`and thereby dilate the lumen of the artery. The balloon
`is then deflated to a small profile, so that the dilatation
`catheter can be withdrawn from the patient’s vascula-
`ture and blood flow resumed through the dilated artery.
`The PTCA procedureis also typically performed with
`the use of a guiding catheter, wherein a conventional
`over-the-wire system is employed.
`In such angioplasty procedures, there may be reste-
`nosis of the artery, which necessitates either another
`angioplasty procedure, a surgical bypass operation, or
`some other method of repairing or strengthening the
`dilated area. Toassist in the prevention of restenosis and
`to strengthen the dilated area, a physician can implant
`an intravascular prothesis, generally called a stent, to
`maintain vascular patencyinside the artery at the site of
`the lesion. Stents are also used to repair vessels having
`a flap or dissection or to generally strengthen a weak-
`ened section of a vessel. The stent is expanded to a
`larger diameter, often by the balloon portion of the
`dilatation catheter. Stents delivered to a restricted coro-
`nary artery, expanded to a larger diameter by a balloon
`catheter, and left in place within the artery at the site of
`the dilated lesion are shown, for example, in U.S. Pat.
`No. 4,740,207 (Kreamer) and U.S. Pat. No. 5,007,926
`Derbyshire).
`"
`Although stents have been used effectively for some
`time, the effectiveness of a stent can be diminished ifit
`is not uniformly implanted within the artery. For exam-
`ple, balloons having a stent placed upon them tend to
`have non-uniform radial expansion dueto the increased
`restriction the stent imposes on the working length of
`the balloon. Consequently, the balloon expandsfirst at
`the proximal and distal balloon ends along the path of
`least resistance, i.e., towards the distal and proximal
`ends of the balloon, which expands the balloon in a
`“dog bone” fashion lacking uniform radial expansion.
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`Thus, when the balloon expands in this “dog bone”
`fashion, the proximal and distal regions of the balloon
`over expand to form a characteristic “dog bone” shape,
`the stent is not expanded uniformly and the stent may be
`improperly implanted.
`Accordingly, those concerned with the design, devel-
`opment, and use of stent implantation systems have long
`recognized the desirability and need for further im-
`provements in systems for uniformly implanting a stent
`in order to maximize stent performance. In this regard,
`what has been needed and, heretofore unavailable, is a
`stent delivery system which controls the radial expan-
`sion ofthe stent alongits entire length to ensure uniform
`expansion.
`
`SUMMARYOF THE INVENTION
`Briefly, and in general terms, the present invention
`provides an improved method and apparatus for con-
`trolling the radial expansion of a catheter balloon used
`to deliver a stent, in order to enhance uniform implanta-
`tion of the stent.
`Moreparticularly, the present invention comprises a
`catheter having first means on the catheter for expand-
`ing a stent, second means cooperating with the first
`means to control the radial expansion characteristics of
`the first means, and third means for controlling the
`radial expansion of the proximal and distal ends of the
`first means. In this way, the stent is more uniformly
`expanded to its implantation diameter and properly
`placed within the vasculature ofa patient.
`In one embodiment, by way of example and not nec-
`essarily by way of limitation, a balloon catheter includes
`an elongated catheter body and a balloon member on
`the distal end of the catheter. The balloon member has
`a proximal end and a distal end with each end having
`tapered balloon segments. Elastic restraining bands
`surround each of these distal and proximal tapered seg-
`ments of the balloon. These restraining bands exert a
`resistive force in response to theresistive force created
`by the addition of the stent on the balloon. An uneven
`expansion is created in the balloon by the existence of
`the stent, thus the restraining bands help to offset this
`force. In orderto further control the radial expansion of
`the balloon, a coaxial elastic sheath or sleeve surrounds
`and is in contact with the balloon member and the re-
`straining bands. This results in only radial displacement
`along the entire length of the balloon. A stent, whichis
`placed over the working length of the balloon,is there-
`fore, uniformly expandedas the balloonis inflated, since
`radial expansion of the balloon is more precisely con-
`trolled.
`Duringinflation of the balloon,the elastic restraining
`bandsexert a force at the proximal and distal endsof the
`balloon equal and opposite to that generated by the
`combinedresistance of the sleeve and the stent tending
`to deform the balloon. In this way, the uneven expan-
`sion (end effects) are limited when the balloon is ex-
`panded which,in turn, inhibits a “dog boning” deforma-
`tion at the proximal and distal regions of the balloon.
`Further, as the balloon inflates, the sleeve surrounding
`the balloon distributes the radial forces evenly over an
`extended area, which then controls the radial expansion
`ofboth the balloon and the surrounding stent carried on
`the balloon.
`In an another embodiment, a catheter includes an
`elongated catheter body and three balloonsat the distal
`end of the catheter. The three balloons comprise a pair
`
`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 5
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 5
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`4
`the artery walls in the eventthe balloon developsa leak,
`which could enable high pressure fluid to escape
`through the leak, knownas “pin-holing.”In either case,
`the sleeve, with or without the restraining bands, forms
`a protective barrier which minimizes the harmfuleffects
`in the event the balloon is punctured ora pin-hole leak
`develops.
`Further, the sleeve and restraining bands also provide
`a substrate for the stent, so that the stent may be secured
`to a balloon in a morepositive manner. The sleeve, with
`or without the restraining bands, provides a cushion for
`the stent to sink into, and provides more friction for the
`stent than the slippery surface of the balloon which may
`be covered with an anti-friction material. Finally, the
`sleeve, with or without the restraining bands allows for
`a decrease in deflation time when the balloon is de-
`flated, after the stent is implanted. The sleeve, with or
`without the restraining bands, reduces the deflation
`time by squeezing the balloon so it will deflate faster.
`Similarly, the sleeve and/or bands ensure that the bal-
`loon will deflate into a uniform, round balloon, and not
`into an undesirable flat or pancake shape, known as
`“balloon winging.” Balloon winging is unacceptable
`becauseit increases thelikelihood that the balloon will
`entangle when it
`is withdrawn from the stent and
`through the coronary arteries.
`Other features and advantages of the present inven-
`tion will become apparent from the following detailed
`description, taken in conjunction with the accompany-
`ing drawings, which illustrate, by way of example, the
`features of the present invention.
`
`3
`of control balloons and a central balloon located be-
`tween the control balloons. In addition, a coaxial elastic
`sleeve surroundsail of the balloons and is in contact
`with the balloons.
`In the latter catheter embodiment, the central balloon
`is formed of a conventional elastic material and is in-
`flated to provide the primary expansion force, i.e., ra-
`dial expansion to a stent which is placed upon the cen-
`tral balloon. It is noted, but not shown, that the stent
`may be placed overall three of the balloons.
`Thecentral balloonis the first of the three balloons to
`be inflated. As the central balloon inflates, it expands
`both radially and longitudinally. In order to control the
`longitudinal expansion, which occursalong the path of
`least resistance, the control balloons are formed of a
`material whichis less compliant than the material form-
`ing the central balloon. One balloon ofthe pair is lo-
`cated proximally of the central balloon and the other
`balloon is located distally. Therefore, as the control
`balloonsare inflated, they limit the longitudinal expan-
`sion of the central balloon by containing the central
`balloon between them.
`Similarly, the elastic sleeve surrounding the three
`balloons controls the radial expansion of the central
`balloon. As discussed in the previous embodiment, the
`sleeve distributes the radial expansion forces generated
`by the central balloon over an extended area,
`thus,
`enabling the radial expansion of the balloon to remain
`more uniform.
`Hence, by using the control balloons to contain the
`longitudinal expansion of the central balloon, and the
`elastic sleeve to control the radial expansion of the
`central balloon, the central balloon expands uniformly
`which, in turn, uniformly expands the stent from its
`smaller insertion diameter to its larger implantation
`diameter. This results in improved stent implantation
`which maximizes stent performance.
`'
`In another embodiment, the tri-balloon structure is
`again utilized, but without an elastic sleeve extending
`overtheballoonsto aid in distributing the radial expan-
`sion forces. In this embodiment, the control balloons
`again limit the longitudinal expansion of the elastic
`central balloon, and the central balloon, as the primary
`expansion balloon, expandsradially upon inflation due
`to its elastic nature. Therefore, the control balloons not
`only limit the longitudinal expansion of the central bal-
`loon by containing the longitudinal expansion of the
`central balloon between them, but the control balloons
`also augmentthe radial expansion ofthe central balloon.
`Consequently, the expansion characteristics of the cen-
`tral balloon are controlled.
`In still another embodiment, the tri-balloon structure
`is utilized either with or withouttheelastic sleeve cov-
`ering the three balloons; however,in this embodiment,
`the central balloon is formed of a material having sub-
`stantially similar elastic properties as the control bal-
`loons. Although the control balloons are no longer
`substantially less compliant than the central balloon, the
`DETAILED DESCRIPTION OF THE
`controlballoonsstill limit the longitudinal expansion of
`PREFERRED EMBODIMENTS
`the central balloon during inflation as described above
`by containing the central balloon between them.
`The present invention comprises a catheter having
`The present invention, in addition to implanting the
`first balloon means for expandingastent, cooperating
`stent, uniformly, reliably, rapidly, and precisely, also
`with meansfor controlling the expansion characteristics
`has numerous other advantages. The elastic sleeve, or
`of the balloon means. In this way, the stent is uniformly
`the sleeve and restraining bands, are between the stent
`expanded to its implantation diameter and properly
`and the balloon memberof the catheter. This prevents
`placed within the vasculature of a patient.
`puncture of the balloon by any protuberance or other
`Referring now to the drawings, wherein like refer-
`irregularity on the stent. This also prevents damage to
`ence numbers denote like or corresponding elements
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`FIG. 1 depicts a partial cross-sectional view of one
`embodimentofthe present invention, illustrating a bal-
`loon catheter having an elastic sleeve and a plurality of
`elastic restraining bands outside the balloon member of
`the catheter, wherein the balloonis deflated;
`FIG.2 depicts a partial cross-sectional view of the
`balloon, the elastic sleeve and the elastic restraining
`bands of FIG. 1, wherein the balloon is inflated;
`FIG. 3 depicts a partial cross-sectional view of an-
`other embodiment ofthe present invention,illustrating
`a tri-balloon catheter and an elastic sleeve surrounding
`the balloons, wherein thetri-balloon portion is deflated;
`FIG. 4 depicts a partial cross-sectional view of the
`elastic sleeve and the three balloons of FIG. 3, wherein
`the tri-balloon catheteris inflated;
`FIG. 5 depicts a partial cross-sectional view of an-
`other embodimentof the present invention,illustrating
`a tri-balloon catheterin its deflated state;
`FIG.6 depicts a partial cross-sectional view of the
`tri-balloon catheter of FIG. 5, showingall three of the
`balloons, in their inflated state; and
`FIG.7 is a transverse cross-sectional view taken sub-
`stantially along lines 7—7 of the catheter shown in FIG.
`6.
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 6
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 6
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`5
`throughout the various figures of the drawings, and
`more particularly to FIGS. 1 and 2, there is shown a
`catheter 20 embodying the novelfeatures of the present
`invention. Catheter 20 includes a longitudinally extend-
`ing outer tubular member 21 with an inflatable balloon
`member 22 near the distal end thereof, and an inflation
`lumen 28. The balloon 22 has a proximal end 26 and a
`distal end 27 with each end having tapered balloon
`segments 26a and 27a respectively. Elastic restraining
`bands 23 surround each of balloon segments 26a and 27a
`(FIG. 2). Restraining bands 23 are sealed to the outer
`tubular member 21 in any acceptable manner, as by way
`of standard adhesive techniques or via standard shrink
`tubing. In addition, an elastic sleeve 24 which is coaxial
`with the catheter, extends over the surface of balloon 22
`and over restraining bands 23 and is in contact with
`both the balloon and the bands. A stent 25 is placed over
`sleeve 24 and positioned between restraining bands 23
`or, alternatively, just slightly over the restraining bands.
`In order to aid in the balloon’s inflation, lubrication,
`such as MICROGLIDET™ coating (or a similar mate-
`rial), marketed by Advanced Cardiovascular Systems,
`Inc. (ACS)of Santa Clara, Calif., is placed betweenall
`the interfacing surfaces of restraining bands 23, balloon
`22 and sleeve 24. This lubrication is used to offset the
`additional friction that is imparted by restraining bands
`23 and sleeve 24 so that balloon 22 is still able to inflate
`without additional difficulty,
`i.e., the purpose of the
`restraining bands and the sleeve is to enhance the uni-
`form expansion ofthe balloon, not to interfere with its
`inflation.
`Balloon member22 of catheter 20 is formed of poly-
`ethylene or other suitable materials well known in the
`art, and is either bonded to outer tubular member 21 in
`an integral manner, as shown,or is made one-piece with
`the outer member. Balloon 22 can beinflated by radi-
`opaquefluid from an inflation port (not shown) extend-
`ing from inflation lumen 28 contained in the catheter
`shaft, or by other means, such as fluid in communication
`from a passageway formed between the outside of the
`catheter shaft and the member forming the balloon,
`depending on the particular design of the catheter. The
`details and mechanics of balloon inflation vary accord-
`ing to the specific design of the catheter, and are well
`knownin theart.
`Asstated above,sleeve 24 is coaxial with the catheter
`20 and it surrounds both balloon 22 and restraining
`bands 23 which are located at proximal 26 and distal 27
`endsof the balloon. The sleeve 24 has an inner diameter
`which is smaller than the outer diameter of balloon 22.
`Accordingly, sleeve 24 is attached to balloon 22 by
`stretching the sleeve over the balloon and restraining
`bands 23. In this way, compression is applied by sleeve
`24 against balloon 22 and restraining bands 23 to form a
`secure seal. Sleeve 24 is also attached to the catheter
`outer tubular member21 at proximal end 26 ofballoon
`22 via standard adhesive techniques or via standard
`shrink tube. Sleeve 24 is attached to proximal end 26 of
`balloon 22, because in the event of a rupture, the sleeve
`will be connected at the end upstream from the location
`of the tear and, thus, the sleeve will not curl or bunch
`when catheter 20 is withdrawn. Thedistal end of sleeve
`24, howeveris not secured to the catheter outer tubular
`member 21 by adhesives. This allows for the translation
`of the sleeve during expansion and the passage offluid
`distal to balloon 22 in the event of a balloon rupture.
`Sleeve 24 may be formed of any suitable material that
`is elastic and resilient. The material is preferably one
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`that has a high degree of linearity (non-plasticity) for a
`wide range of stress and strain values. However, any
`elastic material may be used. Commercially available
`tubing such as “C-FLEX” tubing may be used. “C-
`FLEX”tubing may be obtained from Concept Polymer
`Technologies of Largo, Florida. Further, the material
`should have goodtear strength to prevent fracturing or
`splitting when it is stretched. Suitable materials include
`silicones, latexes, urethanes, polysiloxane modified sty-
`rene-ethylene/butylene-styrene
`block
`copolymers
`(SEBS) and their associated families.
`While it is envisioned, in the embodiment of FIG.1,
`that an elastic material is used to form sleeve 24 in order
`to maximize the benefits of the present invention, it is
`contemplated that other materials may be used, includ-
`ing materials such as the type used to form a balloon
`member of a PTCA catheter, like PE-600, a polyethyl-
`ene based material marketed by Advanced Cardiovas-
`cular Systems, Inc. (ACS) of Santa Clara, Calif. Such
`materials are expandable,i.e., inflatable, but would not
`necessarily have to be resilient, as is the material con-
`templated in the embodiment shown in FIG. 1. There-
`fore, as is knownin the art, materials that constitute the
`balloon members of PTCA catheters are expandable
`fromone diameter to a larger predetermined diameter,
`being preformed to expand to the larger diameter, but
`are not necessarily elastic or resilient.
`Similarly, elastic restraining bands 23 can be formed
`of the same material forming elastic sleeve 24. Alterna-
`tively, restraining bands 23 can be formedof a different
`material than that forming sleeve 24; however, the ma-
`terial chosen to form the restraining bands should have
`the similar elastic properties as that of the sleeve. Suit-
`able materials for this purposes include “TYGON”
`available from U.S. Stoneware Co., or silicone.
`As best observed in FIG. 2, when balloon 22 inflates,
`it expands radially. Restraining bands 23 control the
`expansion of balloon 22 by imparting a force which
`restricts the balloon’s expansion at its proximal and
`distal ends, which is along the path ofleast resistance.
`Sleeve 24 also controls the radial expansion of balloon
`22 by distributing the radial expansion of the balloon
`over an extended area. In other words, restraining
`bands 23 impart a resistance towards the proximal and
`distal ends of the balloon, equivalent to the combined
`resistance of sleeve 24 and stent 25. Thus, the radial
`expansion of balloon 22 is controlled to produce uni-
`form expansion of the stent 25 from its smaller insertion
`diameter to its larger implantation diameter. This novel
`approach eliminates the “dog boning” affect that is
`common with prior art devices.
`In an alternative embodiment, as shownin FIG.3, a
`catheter 20 comprises three balloons 30, 33 and 34 near
`the distal end of the catheter, two inflation lumens 41
`and 44, and an elastic sleeve 24 whichis coaxial with the
`catheter and surrounds andis in contact with the three
`balloons. The three balloons 30, 33 and 34 include a pair
`of control balloons 33 and 34 formed of a non-compliant
`material, and a central balloon 30 which is located cen-
`trally between the control balloons. Control balloon 33
`is located proximal to central balloon 30 and control
`balloon 34 is located distal to the central balloon.
`Distal balloon 34 of the present invention is formed of
`a high pressure material, such as polyester. As shownin
`FIG. 4, distal balloon 34 is attached to outer tubular
`member 21 of catheter 20. A proximal seal 46 of distal
`balioon 34 is completed with the balloon 34 turned
`inside-out and the distal end laying towards the proxi-
`
`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 7
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`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 7
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`mal end of outer tubular member47. Once the proximal
`seal 46 is made, distal balloon 34 is folded back over the
`proximal seal so that distal seal 48 is formed using a -
`standard tip seal technique as is well knownin theart.
`Proximal balloon 33 is similarly formed of a high
`pressure material. It is attached to the outer tubular
`member21in basically the reverse order as the proce-
`dure used to attach distal balloon 34. Proximal balloon
`33 is turned inside-out, but this time with the proximal
`end ofballoon 50 laying towardsthe distal end of outer
`tubular member 51. Distal seal 52 is then completed at
`the same time as the proximal seal 55 of the central
`balloon 30. Finally, proximal balloon 33 is folded back
`towards its proximal end 50 and proximal seal 53 is
`formed using a standard proximal seal technique as is
`well knownin the art.
`Central balloon 30 is formed of a compliant material,
`such as polyethylene. Generally, the entire stent 25 will
`be placed over central balloon 30, however, the stent
`may be placed over proximal and distal balloons 33 and
`34, so long as these balloons also have a suitable work-
`ing surface. Like proximal balloon 33 above, central
`balloon 30 is attached to outer tubular member 21 of
`catheter 20 turning it inside-out, with proximal end 31
`of the central balloon laying towards the distal end of
`outer tubular member 51 to form distal seal 56. Then,
`central balloon 30 is folded back overitself and proxi-
`mal seal 55 is formed, as stated above, at the same time
`distal seal 52 of the proximal balloon 33 is formed.
`Coaxial elastic sleeve 24 is formed of “C-FLEX”or
`other similar elastic material and it surrounds andis in
`contact with balloons 30, 33 and 34. Sleeve 24 has an
`inner diameter which is smaller than the outer diameter
`of balloons 30, 33 and 34. Therefore, sleeve 24 is at-
`tachedto balloons 30, 33 and 34 by stretching and plac-
`ing the sleeve overall three balloons to form a secure
`seal. A stent 25 is placed oversleeve 24, typically, in the
`region overlying central balloon 30. As central balloon
`30 inflates to provide radial expansion,sleeve 24 distrib-
`utes the radial expansion force over an extended area,
`thus making the radial expansion uniform. This in turn
`allows stent 25 to be expanded uniformly for proper
`implantation.
`Central balloon 30 is the first of balloons 30, 33 and 34
`to be inflated and provides the primary radial expansion
`force necessary to expand the stent 25 to its larger im-
`plantation diameter. Inflation of central balloon 30 is
`accomplished through the use of an inflation medium
`from inflation port 40 extending from first inflation
`lumen 41 contained in catheter shaft 21. After central
`balloon 30 has been inflated, proximal and distal bal-
`loons 33 and 34 are inflated via inflation medium from
`two additional inflation ports 42 and 43 which extend
`from a commonsecondinflation lumen 44 contained in
`catheter shaft 21. In FIG.7, a transverse cross-sectional
`view of the catheter shown in FIG. 6 illustrates the
`configuration of inflation lumens 41 and 44 along with
`wire lumen 45.
`Therefore, catheter 20 is inserted into a patient’s vas-
`culature and central balloon 30 is inflated to produce
`both radial and longitudinal expansion of the balloon.
`Next, proximal balloon 33 and distal balloon 34 are
`inflated. Because of their less compliant construction,
`proximal and distal balloons 33:and 34 contain the cen-
`tral balloon 30 between them and, thus, limit the longi-
`tudinal expansion of the central balloon. Likewise,
`sleeve 24 controls the radial expansionofthe balloon 30,
`which,in turn, controls the radial expansionof stent 25.
`
`8
`In still another embodiment,as illustrated in FIG.5,
`the tri-balloon catheter of FIG. 4 can be used without a
`coaxialelastic sleeve 24 surrounding balloons 30, 33 and
`34. Except for the absence of sleeve 24, the tri-balloon
`catheter 20 of this embodiment comprises the same
`structure and is constructed in the same manneras the
`tri-balloon catheter previously described in connection
`with the structure shownin FIG.4.
`As discussed in the aforedescribed embodiment, as
`central balloon 30 inflates, it provides radial expansion
`forces in order to implantstent 25. As central balloon 30
`inflates it also expandslongitudinally, along the path of
`least resistance. By inflating proximal and distal bal-
`loons 33 and 34, the longitudinal expansion of the cen-
`tral balloon 30 is restricted. In turn, the uniform radial
`expansion of central balloon 30 is enhanced. This in turn
`results in a more uniform expansion of stent 25 which
`aids in the uniform implantation of the stent.
`In still another embodiment, the tri-balloon catheter
`20 is utilized either with or without elastic sleeve 24;
`however, in this embodiment, balloons 30, 33 and 34 are
`formed of materials having substantially similarelastic
`properties. Therefore, control balloons 33 and 34 are
`not necessary less compliant than central balloon 30.
`Nevertheless, the catheter of this embodiment performs
`in substantially the same way as previously described.
`The central balloon 30 is inflated first to provide the
`primary radial expansion force necessary to implant
`stent 25. Subsequently, control balloons 33 and 34 are
`inflated to restrict the longitudinal expansionof central
`balloon 30. Although controlballoons 33 and 34 are not
`less compliant than central balloon 30, theystill provide
`adequate containment of the central balloon to restrict
`the longitudinal expansion of the central balloon. Once
`again, this allows for controlled expansion of stent 25
`and more uniform implantation in the patient’s vascula-
`ture.
`It is clear from the above descriptions, that the pres-
`ent inventionfulfills a long felt need for a system which
`can uniformly implant a stent in the vasculature of a
`patient. By controlling the uniform radial expansion of
`a balloon, a more uniform implantation of the stent is
`accomplished.
`It will be apparent from the foregoing that, while
`particular forms of the invention have beenillustrated
`and described, various modifications can be made with-
`out departing from the spirit and scopeof the invention.
`Accordingly, it is not intended that the invention be
`limited, except as by the appendedclaims.
`I claim:
`1. In an intravascular catheter system for implanting
`a stent in a body lumen, the combination comprising:
`a catheter having an elongated catheter body and at
`least one inflation lumen contained therein, said
`catheter body having proximal and distal ends;
`a stent carried upon said catheter;
`a balloon attached to said catheter body near said
`distal end for controllably expanding said stent
`which is mounted thereon, said balloon in fluid
`communication with said inflation lumen to expand
`said balloon radially and longitudinally;
`an elastic sleeve coaxial with and surrounding said
`catheter body to control the radial expansion of
`said balloon; and
`:
`an elastic restraining band positioned at each of the
`distal and proximal endsofsaid balloon to control
`longitudinal expansion of said balloon, whereby
`said stent mounted onsaid balloonis similarly con-
`
`35
`
`45
`
`35
`
`60
`
`65
`
`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 8
`
`Petitioner Edwards Lifesciences Corporation - Exhibit 1024 - Page 8
`
`

`

`9
`trolled in its radial and longitudinal expansion to
`provide a cylindrically shaped stent
`implanted
`within the body lumen.
`2. In an intravascular catheter system for implanting
`a stent in a body lumen, the combination comprising:
`a catheter having an elongated catheter body and at
`least one inflation lumen contained therein, said
`catheter body having proximal and distal ends;
`a stent carried upon said catheter;
`‘a balloon having a proximal and distal end, said bal-
`loon attached to said catheter body