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`EDWARDS LIFESCIENCES EX. 1218
`Edwards Lifesciences v. Boston Scientific Scimed
`U.S. Patent No. 6,915,560
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`US. Patent
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`6,051,002
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`US. Patent
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`Apr. 18, 2000
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`US. Patent
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`US. Patent
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`US. Patent
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`Apr. 18, 2000
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`6,05 1,002
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`1
`STENT CRIMPING DEVICE AND METHOD
`OF USE
`
`BACKGROUND OF THE INVENTION
`
`This invention relates to a stent crimping device of the
`type that will enable the user to uniformly and tightly crimp
`a stent onto the distal end of a catheter assembly, for
`example of the kind used in a typical percutaneous translu-
`minal coronary angioplasty (PTCA) procedure or percuta-
`neous transluminal angioplasty (PTA) procedure.
`In a typical PTCA procedure, for compressing lesion
`plaque against the artery wall to dilate the artery lumen, a
`guiding catheter is percutaneously introduced into the car-
`diovascular system of a patient
`through the brachial or
`femoral arteries and advanced through the vasculature until
`the distal end is in the ostium. A guide wire and a dilatation
`catheter having a balloon on the distal end are introduced
`through the guiding catheter with the guide wire sliding
`within the dilatation catheter. The guide wire is first
`advanced out of the guiding catheter into the patient’s
`coronary vasculature, and the dilatation catheter is advanced
`over the previously advanced guide wire until the dilatation
`balloon is properly positioned across the lesion. Once in
`position across the lesion, a flexible, expandable, preformed
`balloon is inflated to a predetermined size at relatively high
`pressures to radially compress the atherosclerotic plaque of
`the 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 with-
`drawn from the patient’s vasculature and blood flow
`resumed through the dilated artery. While this procedure is
`typical, it is not the only method used in angioplasty. Other
`methods for compressing plaque or removing it are known,
`such as atherectomies or use of plaque dissolving drugs.
`In angioplasty procedures of the kind referenced above, a
`restenosis of the artery may develop over several months,
`which may require another angioplasty procedure, a surgical
`bypass operation, or some method of repairing or strength-
`ening the area. To reduce the likelihood of the development
`of restenosis and strengthen the area, a physician can
`implant an intravascular prosthesis for maintaining vascular
`patency, typically called a stent. A stent is a device used to
`hold tissue in place in a vessel or to provide a support for a
`vessel to hold it open so that blood flows freely. Avariety of
`devices are known in the art for use as stents, including
`expandable tubular members, in a variety of configurations,
`that are able to be crimped onto a balloon catheter, and
`expanded after being positioned intraluminally on the bal-
`loon catheter, and that retain their expanded form. Typically,
`the stent is loaded and crimped onto the balloon portion of
`the catheter, and advanced to a location inside the artery at
`the lesion. The stent is then expanded to a larger diameter,
`by the balloon portion of the catheter, to implant the stent in
`the artery at the lesion. Examples of stents and delivery
`catheters of the type described herein are disclosed in more
`detail in US. Pat. No. 5,102,417 (Palmaz); US. Pat. No.
`5,569,295 (Lam); and US. Pat. No. 5,514,154 (Lau et al.).
`If the stent is not effectively crimped onto the catheter
`balloon portion when the catheter
`is advanced in the
`patient’s vasculature, the stent may move or possibly slide
`off the catheter balloon portion in the coronary artery prior
`to expansion, and may block the flow of blood, requiring
`procedures to remove the stent.
`In procedures where the stent is placed over the balloon
`portion of the catheter, the stent must be compressed or
`crimped onto the balloon portion to prevent the stent from
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`sliding off the catheter when the catheter is advanced in the
`patient’s vasculature. In the past this crimping was often
`done by hand, which does not provide optimum results due
`to the uneven force being applied, resulting in non-uniform
`crimps. In addition, it was difficult to judge when a uniform
`and reliable crimp had been applied. Though some tools,
`such as ordinary pliers, have been used to crimp the stent,
`these tools have not been entirely adequate in achieving an
`effective crimp. Moreover, an ineffectively crimped stent
`may result in an ineffectively expanded stent in the vessel or
`artery, which is undesirable.
`
`SUMMARY OF THE INVENTION
`
`The invention is directed to a crimping tool and method
`of use for enabling effective crimping of a stent onto the
`balloon portion of a catheter in order to better secure a stent
`onto the catheter for low-profile delivery of the stent through
`the patient’s vascular system. The present
`invention
`attempts to solve several problems associated with crimping
`stents onto balloon catheters.
`
`In an exemplary embodiment ofthe present invention, the
`stent crimping tool
`includes a pair of handles pivotally
`engaged such that a first handle member receives within it a
`second handle member. The invention further includes a
`
`cylindrical loop crimping member comprising a flexible
`sheet or film of material, such as a thin piece of Mylar
`material, in the form of a loop. The ends of the loop are
`attached respectively to the first handle and the second
`handle. An application of force on the handles causes the
`prospective ends of the cylindrical loop to move in opposite
`directions thereby providing a tension force which results in
`reducing the opening of the cylindrical loop.
`The invention further provides for mounting a stent on the
`balloon portion of a catheter, and positioning the stent and
`balloon portion of the catheter within the cylindrical loop.
`As the handles of the stent crimping tool are compressed, the
`ends of the cylindrical loop are pulled in opposite directions
`thereby reducing the size of the loop and tightly compress-
`ing the stent in a uniform manner on the balloon portion of
`the catheter.
`
`the
`By releasing the handles, which are biased open,
`cylindrical loop returns to its original size, thereby permit-
`ting the stent and balloon portion of the catheter to be
`removed from the cylindrical loop.
`In one embodiment of the invention, the cylindrical loop
`is formed from a substantially non-stretchable plastic mate-
`rial having a high tensile strength and a low modulus.
`One of the handles of the stent crimping tool includes
`reference indicia relative to the other handle member so that
`
`the reference indicia correspond to the crimping diameter of
`the cylindrical loop. As the two handles are compressed one
`into the other, the reference indicia will indicate the size or
`diameter of the cylindrical loop, and thereby determine the
`ultimate travel and thus, the resultant crimped diameter of
`the stent onto the balloon portion of the catheter.
`These and other advantages of the invention will become
`more apparent from the following detailed description
`thereof when taken in conjunction with the accompanying
`drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a perspective view of an exemplary embodiment
`of the present invention, in which the pivotally-engaging
`member is pivoted into engagement with the receiving
`member.
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`6,05 1,002
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`3
`FIG. 2 is a plan view of the first handle member of the
`crimping tool.
`FIG. 3 is a plan view depicting the second handle member
`of the crimping tool, which is configured for slidably engag-
`ing the first handle member of FIG. 2.
`FIG. 4 is a plan view depicting the first and second handle
`members pivotally engaged so that the cylindrical loop is
`positioned for receiving a stent for crimping onto the balloon
`portion of a catheter.
`FIG. 5 is a plan view depicting the second handle member
`squeezed into the first handle member thereby restricting the
`diameter of the cylindrical loop which provides the crimping
`force on the stent.
`
`FIGS. 6—9 are side elevational views depicting a series of
`crimping steps wherein the cylindrical loop gradually tight-
`ens onto the stent
`thereby crimping it onto the balloon
`portion of the catheter as the loop ends are moved in
`opposite directions.
`FIG. 10 is a perspective view of the cylindrical loop with
`the stent and the balloon portion of the catheter positioned
`within the loop.
`FIG. 11 is a plan view depicting one preferred embodi-
`ment of the cylindrical loop in an uncoiled and flattened
`configuration.
`FIGS. 12A—12C are perspective views depicting various
`embodiments of protective sheaths.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`The present invention provides for a crimping tool which
`uniformly and tightly crimps an expandable stent onto a
`catheter, such as a balloon catheter, so that the stent remains
`removably attached to the catheter until the stent and cath-
`eter are positioned in a body lumen. In keeping with the
`invention, device 10 comprises crimping tool 20 for
`enabling effective crimping of an intravascular stent 11 onto
`the collapsed balloon portion 12 adjacent the distal end 13
`of a balloon catheter assembly 14. In the exemplary embodi-
`ment of device 10, as shown in FIGS. 1—5, crimping tool 20
`is adapted to be held in the hand of the user, so as to enable
`stent 11 and catheter 14 to be supported in tool 20, and to
`enable the user to apply compressive force to tool 20 to
`crimp stent 11 on catheter 14.
`Crimping tool 20 includes first handle member 22, second
`handle member 24 pivotally movable into engagement with
`first handle member 22 in a generally pendulum-like
`movement, and pin 26 pivotally connecting the upper por-
`tions of first handle member 22 and second handle member
`24. First handle member 22 and second handle member 24
`
`are engageable and generally complementary and preferably
`somewhat triangular in shape to ergonomically fit the hand,
`and include slots 28 and 30 therein which are preferably
`somewhat arcuate-shaped. Preferably, first handle member
`22 is configured to receive second handle member 24.
`Crimping tool 20 further includes crimping member 32
`which is disposed within slots 28,30 which is adapted to
`receive stent 11 mounted on balloon portion 12 of the
`catheter assembly 14. Crimping member 32 includes cylin-
`drical loop 34 having first end 36 and second end 38. First
`end 36 of cylindrical loop 34 is attached to first attachment
`member 40 on first handle member 22. Second end 38 of
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`cylindrical loop 34 is attached by second attachment mem-
`ber 42 to second handle member 24. First attachment
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`member 40 and second attachment member 42 can be of any
`design which can removably attach first end 36 and second
`
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`end 38 respectively to the first and second handle members.
`As an example, first attachment member 40 and second
`attachment member 42 can include a snap or jaw-like
`member which grips first end 36 and second end 38 of
`cylindrical loop 34. It is intended, for example, that cylin-
`drical loop 34 be replaceable when it wears out.
`While cylindrical loop 34 can have various configurations
`to suit particular needs, a preferred embodiment is shown in
`FIG. 11. Thus, first end 36 of the cylindrical loop is attached
`to first attachment member 40 on first handle member 22 and
`
`second end 38 is attached by second attachment member 42
`to second handle member 24. As indicated, the first and
`second attachment members can be of any design which can
`removably attach the first and second ends of the cylindrical
`loop to the handle members. In the FIG. 11 embodiment,
`apertures 44,46 are provided as convenient attachment
`means to correspond with a snap or jaw-like member on the
`handle members to help grip and removably attach first and
`second ends 36,38. A slot 48 is provided in the cylindrical
`loop to receive first end 36 to form the loop. Flanges 49 are
`provided to prevent the loop overtravel. The width 45 of the
`cylindrical loop should coincide with the length of the stent
`which typically is from about 6 mm to 30 mm. The width
`can be selected to accommodate either shorter or longer
`stents as necessary. Preferably, width 45 is selected so that
`the full length of the stent is covered by the cylindrical loop
`since it generally is undesirable to crimp less than the entire
`stent length at one time. The cylindrical loop can be formed
`of any non-stretchable material, and preferably is formed of
`Mylar or a similar flexible, but non-stretchable plastic mate-
`rial.
`
`In a manufacturing context, the crimping tool can be used
`repeatedly to crimp stents onto the balloon portion of
`catheters. Repeated use will result in the cylindrical loop
`wearing out, whereby it should be replaced. Thus,
`it is
`contemplated that first attachment member 40 second attach-
`ment member 42 provide means for releasing the ends of the
`cylindrical loop and accepting ends of a replacement cylin-
`drical loop for further use. Additionally, an adhesive may be
`used to permanently attach first end 36 and second end 38 to
`the handle members, for use in those situations where the
`crimping tool 20 is designed for a single-use application, as
`will be described.
`
`Crimping tool 20 also is adapted for a single-use
`application, for example, by a cath lab physician or cath lab
`personnel. In that situation, crimping tool 20 can be dis-
`carded after the stent is crimped onto the balloon portion of
`the catheter. Further, first attachment member 40 and second
`attachment member 42 can be a permanent attachment, as
`opposed to a removable attachment to attach the ends of the
`cylindrical loop to the handle members.
`In the preferred method of use, as shown in FIGS. 6—10,
`stent 11 is first positioned over balloon portion 12 by hand,
`and then catheter assembly 14 is moved within cylindrical
`loop 34 to receive the crimping procedure. For ease of
`illustration, FIGS. 6—10 depict loop 34 as having no or very
`little width, however, loop 34 should preferably have a width
`that approximates the length of the stent, which typically
`may be 20 mm or more as previously described for thc FIG.
`11 embodiment. First handle member 22 and second handle
`
`member 24 are compressed together thereby moving ends
`36, 38 in opposite directions as depicted in FIGS. 6—9. As the
`opening of cylindrical loop 34 becomes smaller, the loop
`tightens around stent 11 thereby crimping it onto the balloon
`portion of the catheter. Reference indicia 50 on second
`handle member 24 corresponds to the size or diameter of
`cylindrical loop 34. Thus, one using the crimping tool can
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`6,05 1,002
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`5
`easily determine the crimping force, and importantly, the
`crimped diameter of the stent on the balloon portion of the
`catheter. Thus, the reference indicia correspond to the final
`diameter, or crimped diameter of the stent, thereby taking
`the guesswork out of the crimping procedure as it relates to
`the amount of force applied to the stent and the final crimped
`diameter.
`
`The first and second handle members are biased open,
`such as by a coil spring or other biasing means, so that when
`the compressive force of the user’s hand is released, the
`handles will move open and away from each other. When the
`handles move open, cylindrical loop 34 has enough resil-
`iency in the material that it naturally will open, allowing the
`crimped stent and balloon catheter assembly to be with-
`drawn.
`
`In each of the embodiments of the crimping tool, sheath
`60 can be positioned over the stent, preferably prior to
`crimping the stent. The sheath can have various configura-
`tions such as those shown in FIGS. 12A—12C, and prefer-
`ably has sufficient length and wall thickness to cover the
`stent and uniformly distribute the crimping forces applied to
`the stent by crimping tool 20. As the crimping tool applies
`force to the sheath, the force is evenly distributed over the
`sheath and hence to the stent. The sheath can be left on the
`
`stent after crimping and provide a cover to protect the stent
`in a safe manner until just before the stent is implanted in the
`patient.
`In one preferred embodiment of sheath 60, slots 61 are
`formed in the sheath so that strips 62 in between the slots
`cover specific portions of the stent to prevent fish scaling
`during the crimping process. Fish scaling, which results
`from portions of the stent moving radially outwardly due to
`uneven crimping forces, can occur during the crimping
`process with some stent configurations. Thus, strips 62 are
`positioned over portions of the stent susceptible to fish
`scaling to counteract the effect and maintain a cylindrical
`geometry in the stent.
`The sheath can be formed from an elastic material known
`
`in the art and can have various thicknesses depending on the
`particular stent configuration. Slots 51 or other apertures 54
`are formed in the sheath using a laser or by other means
`known in the art. The sheath is removed prior to implanting
`the stent in the patient.
`It is contemplated that the present invention crimping tool
`20 can be used in a manufacturing facility having a sterile
`environment to be used multiple times to crimp multiple
`stents on catheter assemblies. It is also contemplated that the
`crimping tool 20 will be used for single use applications by
`cath lab personnel, where a stent is crimped onto the balloon
`portion of a catheter, and the tool is then discarded, since
`there is no assurance that the tool can be sterilized after the
`
`single use application in the cath lab.
`While certain dimensions and materials of manufacture
`have been described herein, modifications can be made
`without departing from the scope and spirit of the invention.
`While in the preferred embodiment the stent described is
`intended to be an intraluminal vascular prosthesis for use
`within a blood vessel, such as a saphenous vein, coronary
`artery, carotid artery, etc., and the balloon delivery catheter
`is of the same or similar to that used in therapeutic coronary
`angioplasty, it will be appreciated by those skilled in the art
`that modifications may be made to the present invention to
`allow the present invention to be used to crimp any type of
`stent onto any catheter. The present invention is not limited
`to stents that are deployed in a patient’s vasculature, but has
`wide applications to loading any type of graft, prosthesis,
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`the stent may be
`liner or similar structure. Furthermore,
`delivered and implemented not only into coronary arteries,
`but into any body lumen. Other modifications can be made
`to the present invention by those skilled in the art without
`departing from the scope thereof.
`What is claimed is:
`1. A device for crimping a stent onto a balloon catheter
`assembly, comprising:
`a pair of handles including a first handle member config-
`ured for pivotable engagement with a second handle
`member and a pivot pin extending through each of the
`handle members;
`a crimping member including a strip that is looped and
`having a first end and a second end, the first end being
`attached to the first handle member and the second end
`being attached to the second handle member;
`the looped strip forming a substantially cylindrical loop
`for receiving the stent and balloon catheter assembly,
`whereby the stent and balloon catheter assembly are
`positioned within the cylindrical loop and the first and
`second handle members are squeezed together so that
`the first and second ends of the crimping member move
`in opposite directions thereby constricting the cylindri-
`cal loop to a smaller diameter and forcibly compressing
`the stent onto the balloon catheter assembly.
`2. A device as in claim 1, wherein the second handle
`member is configured to receive the first handle member
`when the handle members are squeezed together.
`3. A device as in claim 1, wherein the first and second
`handles are ergonomically shaped in a substantially
`triangular-shaped configuration to fit the hand.
`4. A device as in claim 1, wherein the crimping member
`is formed from a non-stretchable plastic material.
`5. A device as in claim 4, wherein the non-stretchable
`plastic material
`includes material having a high tensile
`strength and a low elastic modulus.
`6. A device as in claim 1, wherein the handles are formed
`from a rigid plastic.
`7. Adevice as in claim 1, wherein the first handle member
`includes reference indicia relative to the second handle
`
`the reference indicia correspond to the
`member so that
`crimping diameter of the cylindrical loop.
`8. Adevice as in claim 1, wherein the first handle member
`and the second handle member include a first attachment
`
`member and a second attachment member respectively
`associated therewith for attaching the first end and the
`second end of the crimping member to the first handle
`member and the second handle member.
`
`9. A device for crimping a stent onto a balloon catheter
`assembly, comprising:
`first and second handles pivotably connected at a common
`location;
`a strip curved into a loop and having first and second ends,
`wherein the first end is attached to the first handle and
`the second end is attached to the second handle;
`wherein the stent and balloon assembly are positioned
`within the loop, and squeezing the handles pulls the
`first and second ends in opposite directions collapsing
`the loop and crimping the stent onto the balloon assem-
`bly.
`10. The crimping device of claim 9, wherein the first and
`second handles each includes opposite ends and the handles
`are pivotably connected at a common end, and wherein each
`handle includes a slot formed adjacent to the hinged ends
`and the loop is disposed in the slot.
`11. The crimping device of claim 9, wherein the strip
`includes a slot and the first end of the strip passes through
`the slot.
`
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`6,05 1,002
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`7
`12. A method of crimping an intravascular stent onto a
`balloon catheter assembly, comprising:
`positioning an intravascular stent over the balloon portion
`of the catheter assembly;
`placing the stent and balloon portion of the catheter
`assembly in a radially compressible device;
`disposing the stent and balloon portion of the catheter
`Within a strip curved into a cylindrical loop having a
`pair of ends, the pair of ends being attached to a pair of
`handle members hinged for pivotal movement;
`
`8
`applying leveraged pivotably-engageable compressive
`force to the pair of handle members to pull the ends and
`collapse the loop to crimp the stent onto the balloon
`portion of the catheter; and
`
`releasing the compressive force, to enable removal of the
`crimped stent and the balloon portion of the catheter
`together from the radially compressible device.
`
`Page 12 of 13
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`CERTIFICATE OF CORRECTION
`
`PATENTNO.
`
`:6,051.002
`
`DATED
`
`:Apr. 18, 2000
`
`'NVENTOH(S) : Stephen A. Morales
`
`It is certified that error appears in the above-identified patem and that said Letters Patent is hereby
`corrected as shown below:
`
`Title page, under "U.S. PATENT DOCUMENTS”, add the following:
`-—1,966,543
`7/1934
`O'Russa——.
`
`Title page, under "FOREIGN PATENT DOCUMENTS" add the following:
`-—0 938 880
`9/1999
`European Pat. Off.,
`297 14 857U
`10/1997
`Germany,
`0 303 889
`2/1989
`European Pat. Off.,
`975 797 A
`3/1951
`France--.
`
`Title page, under "OTHER PUBLICATIONS", line 2, after "1977",
`delete "No Drawings are enclosed", and delete the
`duplication at lines 19 & 20, and line 24, after "1998",
`delete "Lost? Not available."
`
`
`
`Signed and Sealed this
`
`Third Day of April, 2001
`
`74% PM;
`
`NICHOLAS P. GODICI
`
`Arresting Officer
`
`AcriIig Direcmr nflhe Uniled Slates Patent and Trademark Offirc
`
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