(12) United States Patent
`(10) Patent No.:
`US 6,167,605 B1
`
`Morales
`(45) Date of Patent:
`Jan. 2, 2001
`
`USOO6167605B1
`
`(54) COLLET TYPE CRIMPING TOOL
`
`(75)
`
`Inventor: Stephen A. Morales, Mountain View,
`CA (US)
`
`(*) Notice:
`
`(73) Assignee: Advanced Cardiovascular Systems,
`Inc. Santa Clara CA (US)
`’
`’
`This patent issued on a continued pros-
`ecution application filed under 37 CFR
`1.53(d), and is subject to the twenty year
`patent
`term provisions of 35 U.S.C.
`154(a)(2).
`
`4,987,722 *
`5,026,377 *
`5,132,066
`5,133,732
`5,183,085
`
`5,540,124
`5,546,646
`5,626,604
`596309830
`*
`5,736,25 1
`5,810,873 *
`5,893,867 *
`
`1/1991 Koebbeman .
`........................ 606/108
`6/1991 Burton et a1.
`7/1992 CharleSWOfih 6t a1~ ~
`7/1992 Wiktor .
`2/1993 Timmermans .
`
`.
`
`7/1996 thoj~
`8/1996 Williams et a1.
`5/1997 Cottone, Jr.
`.
`5/1997 Verbeek-
`4/1998 Pinchuck .............................. 428/447
`
`9/1998 Morales ............ 606/198
`........................ 606/108
`4/1999 Burton et a1.
`
`FOREIGN PATENT DOCUMENTS
`
`Under 35 U.S.C. 154(b), the term of this
`patent shall be extended for 0 days.
`
`W0 97 09946
`
`3/1997 (WO) .
`
`(21) Appl. No.: 08/928,877
`
`(22)
`
`Flled:
`
`7
`
`Sep. 12’ 1997
`
`Int. Cl.
`(51)
`(52) US. Cl.
`
`..................................................... B21D 39/04
`................................ 29/282; 29/2835; 606/1;
`606/198; 623/1
`29/283 5 243 522
`(58) Field of Search
`29/234 235243519237 243:5, 243.518,
`515, 282; 279/42; 72/402; 606/1, 108, 198;
`623/1
`
`(56)
`
`References Cited
`US. PATENT DOCUMENTS
`
`8/1873 can ’
`141992 *
`3/1897 Adams .
`579,214 *
`4/1907 Neal
`852 290 *
`3/1909 Keiin .
`915,184 *
`1,045,886 * 12/1912 Reay.
`1,230,561 *
`6/1917 Chige.
`1,268,171 *
`6/1918 Spaulding .
`1,758,261 *
`5/1930 Leland .
`274657433 *
`3/1949 Domger -
`3,496,684 *
`2/1970 Banning et a1.
`*
`3’898’897
`8/1975 Jaumamen ’
`4,107,964
`8/1978 Smith.
`4,215,871 *
`8/1980 Hirsch et al.
`4,907,336
`3/1990 Gianturco .
`
`.
`
`.
`
`OTHER PUBLICATIONS
`
`The eXTraordinary Stent, C.R. Bard Brochure (Undated).
`
`* cited by examiner
`
`Primary Examiner—S. Thomas Hughes
`Assistant Examiner—Jermie E. Cozart
`(74) Attorney, Agent, or Firm—Fulwider Patton Lee &
`UteCht> LLP
`(57)
`
`ABSTRACT
`
`A sterile tool for crimping a stent onto a balloon catheter is
`disclosed. The stent crimping tool
`includes two major
`components, a cylindrical body having external threads and
`a rotating collar with internal threads engaging the external
`.
`.
`.
`.
`.
`threads. The collet end of the cylindrical body is split into
`segmented jaws that are biased to flare outward in an open
`state. A stent loaded onto a balloon catheter and situated
`inside the open segmented jaws can undergo a crimping
`operation when the collar is rotated and advances toward the
`flared open segmented jaws. When the collar engages the
`segmented jaws, the jaws are forced to converge and close
`onto the stent-catheter assembly thereby crimping the stent
`onto the balloon catheter.
`
`16 Claims, 2 Drawing Sheets
`
`IPR2017-00444 EX. 2042
`
`Edwards Lifesciences v. Boston Scientific
`
`US. Patent N0. 6,915,560
`
`Page 1 of 8
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`Page 1 of 8
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`

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`US. Patent
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`Jan.2,2001
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`Sheet1,0f2
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`US 6,167,605 B1
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`US. Patent
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`Jan. 2, 2001
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`US 6,167,605 B1
`
`1
`COLLET TYPE CRIMPING TOOL
`
`BACKGROUND OF THE INVENTION
`
`The present invention relates to an apparatus for loading
`a tubular graft, such as a stent, onto the distal end of a
`catheter assembly of the kind used, for example, in percu-
`taneous transluminal coronary angioplasty (PTCA)
`procedures, in percutaneous transluminal angioplasty (PTA)
`procedures, atherectomies, and the like.
`In typical 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 vasculature until the distal end of the
`guiding catheter is in the ostium of the aorta leading to the
`coronary arteries. 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 arterial lesion. Once in position across
`the lesion, a flexible and expandable balloon is inflated to a
`predetermined size with a radiopaque liquid 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 withdrawn from the patient’s vasculature and the blood
`flow resumed through the dilated artery. As should be
`appreciated by those skilled in the art, while the above-
`described procedure is typical, it is not the only method used
`in angioplasty.
`In angioplasty procedures of the kind referenced above,
`restenosis of the artery may develop at or near the treatment
`area, which may require another angioplasty procedure, a
`surgical bypass operation, or some other method of repairing
`or strengthening the area. To reduce the likelihood of the
`development of restenosis and to strengthen the area, a
`physician can implant an intravascular prosthesis for main-
`taining vascular patency, commonly known as a stent, inside
`the artery at the treated area. The stent is transported in its
`delivery diameter through the patient’s vasculature. At the
`deployment site, the stent is expanded to a larger diameter,
`often by inflating the balloon portion of the catheter. The
`stent also may be of the self-expanding type.
`Since the catheter and stent travel through the patient’s
`vasculature, and typically through the coronary arteries, the
`stent must have a small delivery diameter and must be firmly
`attached to the catheter until
`the physician is ready to
`implant it. Thus, the stent must be loaded onto the catheter
`so that it does not interfere with delivery, and it must not
`come off the catheter until it is implanted.
`In procedures where the stent is placed over the balloon
`portion of the catheter, it is necessary to crimp the stent onto
`the balloon portion to reduce its diameter and to prevent it
`from sliding off the catheter when the catheter is advanced
`through the patient’s vasculature. Non-uniform crimping
`can result in sharp edges being formed along the now uneven
`surface of the crimped stent. Furthermore, non-uniform stent
`crimping may not achieve the desired minimal profile for the
`stent and catheter assembly. Where the stent is not reliably
`crimped onto the catheter, the stent may slide off the catheter
`and into the patient’s vasculature prematurely as a loose
`foreign body, possibly causing blood clots in the
`vasculature, including thrombosis. Therefore, it is important
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`to ensure the proper crimping of a stent onto a catheter in a
`uniform and reliable manner.
`
`This crimping is often done by hand, which can be
`unsatisfactory due to the uneven application of force result-
`ing in non-uniform crimps. In addition,
`it
`is difficult
`to
`visually judge when a uniform and reliable crimp has been
`applied.
`Some self-expanding stents are difficult to load by hand
`onto a delivery device such as a catheter. Furthermore, the
`more the stent is handled the higher the likelihood of human
`error, which would be antithetical to a properly crimped
`stent. Accordingly, there is a need in the art for a device for
`reliably crimping a stent onto a catheter.
`There have been attempts at devising a tool for crimping
`a stent onto a balloon delivery catheter. An example of such
`a tool comprises a series of plates having substantially flat
`and parallel surfaces that move in a rectilinear fashion with
`respect to each other. A stent carrying catheter is disposed
`between these surfaces, which surfaces crimp the stent onto
`the outside of the catheter by their relative motion and
`applied pressure. The plates have multiple degrees of free-
`dom and may have force-indicating transducers to measure
`and indicate the force applied to the catheter during crimp-
`ing of the stent.
`loading tool design is comprised of a
`Another stent
`tubular member housing a bladder. The tubular member and
`bladder are constructed to hold a stent that is to be crimped
`onto a balloon catheter assembly. Upon placement of the
`stent over the balloon portion of the catheter, a valve in the
`loading tool is activated to inflate the bladder. The bladder
`compresses the stent radially inward to a reduced diameter
`onto the balloon portion of the catheter to achieve a snug fit.
`In this way, the stent is crimped onto the distal end of a
`balloon catheter with a minimum of human handling. The
`foregoing stent crimping tools are disclosed in, for example,
`commonly owned and assigned US. Pat. Nos. 5,437,083
`and 5,546,646 to Williams et al.
`Yet another stent crimping tool is known in the art as the
`BARD XT, which is actually a stent loader. It is constructed
`of a tubular body with a ball at one end connected to a
`plurality of long, thin strips passing through the rigid tubular
`body. An uncrimped stent is placed over the plurality of
`long, thin strips, which hold the stent in an expanded state.
`The balloon portion of a catheter is inserted into the cylin-
`drical space formed by the plurality of strips. When the user
`pulls on the ball while holding the tubular body against the
`stent, the strips are slid from beneath the stent and the stent
`is transferred onto the balloon portion.
`Still another conventional stent crimping tool is manu-
`factured by JOHNSON & JOHNSON and appears similar to
`a hinged nutcracker. Specifically, the tool is comprised of
`two hand operated levers hinged at one end and gripped in
`the palm of the hand at the opposite end. A cylindrical
`opening holding a crimping tube is provided through the
`mid-portion of the tool to receive therein a stent loaded onto
`a balloon catheter. The crimping operation is performed by
`the user squeezing the handle thereby pressing the crimping
`tube which in turn pinches the stent onto the balloon
`catheter.
`
`While the prior art devices are suitable for crimping stents
`onto balloon catheters, they suffer from problems such as
`non-uniform crimping forces,
`resulting in non-uniform
`crimps, and they are unsuitable for use by physicians in a
`cath lab who desire to crimp the stent onto the balloon
`catheter.
`
`SUMMARY OF THE INVENTION
`
`The present invention is directed to a method and appa-
`ratus for crimping an intravascular stent onto the distal end
`
`Page 4 of 8
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`

`US 6,167,605 B1
`
`3
`of a catheter. The apparatus is comprised of a cylindrical
`body having a gripping end and a collet end, wherein the
`cylindrical body at the collet end transitions into a plurality
`of segmented jaws that are flared outward. Threads are
`disposed on the cylindrical body in between the collet end
`and the gripping end. A collar is rotatably mounted on the
`cylindrical body and has an internal
`threaded opening
`engaging the threads on the body and a front inside diameter
`of the internal threaded opening that engages the plurality of
`segmented jaws, wherein advancing the collar along the
`threads translates the front inside diameter over the flared
`
`segmented jaws to converge the jaws into a closed state.
`In a preferred embodiment, a groove is formed along a
`length of each jaw so that when the plurality of segmented
`jaws are in the closed state, the grooves collectively form a
`cylindrical cavity leading to an opening at the collet end of
`the cylindrical body. Thus, closing the segmented jaws onto
`the stent mounted to the balloon portion of the catheter when
`the stent and catheter are situated within the cavity crimps
`the stent onto the catheter.
`
`In the preferred embodiment, the present invention crimp-
`ing apparatus has four segmented jaws and each segmented
`jaw includes a generally quarter-circle, cross-sectional
`shape. The segmented jaws may be modified with a liner,
`various coatings, foam plates, or a floating head. Such
`modifications are aimed at gripping and holding the stent
`without damaging the part. Moreover, when the converged
`segmented jaws in the closed state are lined,
`the lining
`material ensures a constant diameter crimp. The diameter
`can be adjusted by changing the thicknesses or shapes of the
`lining material.
`In the preferred embodiment of the present invention, the
`tool is designed to be used in a cath lab to crimp intravas-
`cular stents onto balloon catheters by forcing the stent to
`compress from four points around its circumference onto the
`exterior diameter of the balloon. The balloon with the
`
`uncrimped stent mounted in the correct position thereon is
`placed inside the flared collet end of the cylindrical body
`with the collar threaded thereon half way toward the flared
`collet end.
`
`The balloon and stent are held in position by a third party,
`a table, or other support. While the balloon and stent are
`supported, another person can twist the collar to advance it
`along the length of the threads thereby forcing the seg-
`mented jaws at the collet end to converge and close down on
`to the stent. This closing action crimps the stent onto the
`balloon.
`
`As mentioned earlier, grooves are formed along the length
`of each jaw so that
`in their closed state,
`the grooves
`collectively form a cylindrical cavity the dimensions and
`shape of which match the crimped stent and contain the
`crimped stent and the catheter balloon when the segmented
`jaws have fully converged. The grooves may be profiled to
`vary the diameter and contours along the length of the
`crimped stent. Some resistance should be encountered, but is
`normal to the compression process. The stent and catheter
`balloon can be released from the tool by unscrewing the
`collar from the cylindrical body thereby releasing the exter-
`nal pressure on the converged segmented jaws allowing the
`jaws to open.
`If the crimping process is not satisfactory, the process can
`be repeated for as many times as the user would wish. The
`tool and the operation thereof are extremely simple and
`repeatable. Indeed, with the rotating motion of the collar
`along the cylindrical body, it is possible to mark the tool for
`the precise distance the collar is advanced along the threads
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`of the cylindrical body for accurate crimping of the stent by
`the converging segmented jaws.
`The present invention thus provides the end user with a
`precise and repeatable method of crimping a stent onto a
`balloon catheter. To achieve precision, the present invention
`may be modified with an optional micrometer, strain gauges,
`or the like for tight control. In contrast, many conventional
`processes are unreliable and achieve inconsistent and non-
`uniform crimps. Furthermore, the present invention crimp-
`ing tool can be used with any stent that is released without
`a delivery system. The crimping tool may also be sold alone.
`Finally, the present invention tool solves a common problem
`with conventional tools of not being able to crimp down to
`any exact diameter. These and other advantages of the
`present
`invention will become more apparent from the
`following detailed description when taken in conjunction
`with the accompanying drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is an elevational view, partially in section, depict-
`ing an intravascular stent that is mounted on a delivery
`balloon catheter and disposed within a vessel.
`FIG. 2 is a perspective view of a preferred embodiment of
`the present invention crimping tool showing the segmented
`jaws in the open state.
`FIGS. 3A and 3B show a side elevational and a front view,
`respectively, of a preferred embodiment cylindrical body
`having a gripping end and a flared collet end with the
`segmented jaws in the flared open state.
`FIGS. 4A and 4B depict a side elevational and a front
`view, respectively, of a preferred embodiment collar having
`internal threads, a leading edge, and a knurled exterior.
`FIG. 5 is a side elevational view of the present invention
`wherein a catheter-stent assembly has been loaded into the
`collet end just prior to the crimping operation.
`FIG. 6 is a side elevational view of the present invention
`crimping tool shown in FIG. 5, wherein the crimping
`operation has occurred and the segmented jaws have con-
`verged onto the stent-catheter assembly due to advancement
`of the collar along the cylindrical body of the crimping tool.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`FIG. 1 illustrates intravascular stent 10 which is mounted
`
`onto delivery catheter 11. Stent 10 generally comprises a
`plurality of radially expandable cylindrical elements 12
`disposed generally coaxially and interconnected by mem-
`bers 13 disposed between adjacent cylindrical elements 12.
`Delivery catheter 11 has an expandable portion or balloon 14
`for expanding stent 10 within artery 15 or other vessel.
`Artery 15, as shown in FIG. 1, has dissected lining 16 which
`has occluded a portion of the arterial passageway.
`Delivery catheter 11, onto which stent 10 is mounted, can
`be essentially the same as a conventional balloon dilatation
`catheter for angioplasty procedures. Balloon 14 may be
`formed of suitable materials such as polyethylene, polyvinyl
`chloride, polyethylene terephthalate and other like poly-
`mers. In order for stent 10 to remain in place on balloon 14
`during delivery to the site of the damage within artery 15,
`stent 10 is compressed onto balloon 14. This compressing
`step is known as crimping.
`An optional retractable protective delivery sleeve or
`sheath 20 may be provided to further ensure that stent 10
`stays in place on balloon 14 of delivery catheter 11 and to
`prevent abrasion of the body lumen by the open surface of
`
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`

`US 6,167,605 B1
`
`5
`stent 10 during delivery to the desired arterial location.
`Other means for securing stent 10 onto balloon 14 may also
`be used, such as providing collars or ridges on the ends of
`the working portion, i.e., the cylindrical portion of balloon
`14.
`
`The catheter-stent assembly can be introduced into the
`patient’s vasculature through processes known in the art,
`generally immediately after PTCA, PTA, or atherectomy
`procedures. Briefly, guide wire 18 is disposed across the
`treated arterial section, referred to as target area 16, and the
`catheter-stent assembly is advanced over guide wire 18
`within artery 15 until stent 10 is directly under target area 16.
`Prior to inflation of balloon 14, delivery sleeve 20 is
`retracted to expose stent 10. Balloon 14 of delivery catheter
`11 is then expanded using an inflation fluid. Expansion of
`balloon 14 in turn expands stent 10 into contact with artery
`15. Next, balloon 14 is deflated and catheter 11 is withdrawn
`leaving stent 10 to support the target area 16. As mentioned
`above,
`in order to ensure proper seating of stent 10 on
`balloon 14, and to ensure proper deployment of stent 10 at
`target area 16 within artery 15, the stent crimping procedure
`is highly critical.
`In order to implant stent 10 in a vessel, it is first mounted
`onto inflatable balloon 14 on the distal extremity of delivery
`catheter 11. Stent 10 is crimped down onto balloon 14 to
`ensure a low profile. The present invention addresses this
`crimping procedure.
`FIG. 2 provides a perspective view of a preferred embodi-
`ment of the present invention stent crimping tool 22. In the
`preferred embodiment shown, stent crimping tool 22 is
`comprised of cylindrical body 25 having gripping end 26
`opposed to collet end 28. Collet end 28 is comprised of a
`plurality of flared open segmented jaws 30 formed by
`splitting collet end 28 into discrete branches.
`Cylindrical body 25 further includes external threads 32
`disposed in between gripping end 26 and collet end 28. The
`present invention stent crimping tool 22 further includes
`rotating cylindrical collar 34 having internal threads that
`engage external threads 32 of cylindrical body 24. Cylin-
`drical collar 34 also includes leading edge 36 designed to
`engage segmented jaws 30 as collar 34 is advanced forward
`toward collet end 28. As this engagement progresses, lead-
`ing edge 36 forces segmented jaws 30 from their flared open
`state into a closed state in which all segmented jaws 30
`converge toward a theoretical axial center line of cylindrical
`body 24. FIG. 2 further illustrates optional groove 38
`preferably formed into each segmented jaw 30 that extends
`the length of each jaw 30.
`As best seen in FIGS. 3A and 3B, which provide a side
`elevational view and a front view, respectively, of a pre-
`ferred embodiment of cylindrical body 24, groove 38 tran-
`sitions at confluence point 40 into bore 42 extending the
`length of cylindrical body 24. Gripping end 26 may be
`optionally knurled to provide a better gripping surface.
`Other finishing methods known in the art can be used to
`enhance the friction at this point as well.
`Cylindrical body 24 preferably is approximately 3.75
`inches long, however, this length can vary depending upon
`the application. At gripping end 26, the edges are chamfered
`44 and as mentioned earlier, a section of cylindrical body 24
`just beyond chamfer 44 is knurled for better gripping. Just
`beyond knurled portion 46 are external threads 32 which in
`the preferred embodiment are a 5 degree coarse thread.
`External threads 32 wind to approximately 2.5 inches up the
`shaft of cylindrical body 24. Then the profile of cylindrical
`body 24 flares out at a preferable 4 degree angle from its
`
`6
`center axis, and transitions into collet end 28. Collet end 28
`is not only flared out but is also split down the shaft 2.5
`inches where the threads begin, approximately coinciding
`with confluence point 40. The split is preferably a 4 degree
`taper that begins at the 2.5 inches mark from gripping end
`26 and expands at 4 degrees relative to the center axis to
`collet end 28, creating an approximate 0.189 inch gap
`between the ends of cylindrical body 24.
`In this embodiment, collet end 28 is split into preferably
`four discrete segmentedjaws 30 and each segmented jaw 30
`flares outward at an approximate 4 degree angle relative to
`the axial center line of cylindrical body 24. Segmented jaws
`30 are preferably formed from four quarter-tube sections
`defined by a small inner radius of 0.007 inch. In their flared
`open state, the outside diameter of flared open segmented
`jaws 30 is approximately 1.205 inch contrasted with the
`preferably 1 inch diameter of the unflared section of cylin-
`drical body 24. Groove 38 formed in each segmented jaw 30
`is best seen in the front view of cylindrical body 24 in FIG.
`3B.
`
`FIGS. 4A and 4B provide a side elevational view and a
`front view, respectively, of cylindrical collar 34 that
`is
`rotatably mounted to cylindrical body 24. In the preferred
`embodiment shown in FIGS. 4A and 4B, cylindrical collar
`34 has a generally cylindrical shape with a first diameter, and
`has leading edge 36 with a smaller second diameter.
`Therefore, as seen in the side elevational view of FIG. 4A,
`cylindrical collar 34 preferably has a step down diameter.
`Cylindrical collar 34 is thus a two-stage cylinder that in the
`preferred embodiment is approximately 1.5 inch in length
`with a maximum diameter of 2 inches. The inner diameter is
`
`a constant at 1 inch, and is tapped with a 5 degree coarse
`internal thread 50 to match external threads 32 on cylindrical
`body 24. The large diameter section of cylindrical collar 34
`is preferably 1 inch in length and has a 2 inch diameter, and
`is further chamfered on both edges. This section also is
`knurled 52 to facilitate a better grip on the part.
`Leading edge 36 has a 0.5 inch length and is cut down in
`diameter to preferably 1.5 inch. Leading edge 36 is signifi-
`cant in forcing the flared outward segmented jaws 30 from
`the open state into the closed state in which each segmented
`jaw 30 converges toward the axial center line of cylindrical
`body 24.
`FIGS. 5 and 6 are side elevational views of a preferred
`embodiment of the present invention stent crimping tool 22.
`In FIG. 5, segmented jaws 30 are flared open to receive
`balloon catheter 11 with stent 10 loaded onto balloon 14. The
`
`stent-balloon catheter assembly are shown in FIG. 5 situated
`within a space or cavity 58 formed by segmented jaws 30 in
`their flared open state.
`As mentioned earlier, the present invention stent crimping
`tool 22 is designed to be used in a cath lab to crimp stents
`onto the balloon portion of catheters by compressing the
`stent onto the balloon from preferably four points around its
`outer circumference. Therefore, as seen in FIG. 5, balloon
`14, with the uncrimped stent mounted in the correct position,
`is placed inside collet end 28 of cylindrical body 24. At this
`stage, cylindrical collar 34 has already been threaded half-
`way toward collet end 28, preferably 1.5 inch as measured
`from the back edge of gripping end 26. The stent-catheter
`assembly can be advanced in through either method until it
`is aligned in the collet segments.
`In the cath lab, ideally, the stent-catheter assembly is held
`in position by a third party, a table, or other support known
`in the art. While the stent-catheter assembly is supported,
`another person can twist cylindrical collar 34 thereby
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`US 6,167,605 B1
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`7
`advancing collar 34 along cylindrical body 24 in the direc-
`tion of arrow 54.
`
`In this motion, leading edge 36 is translated into engage-
`ment with segmented jaws 30. The preferably smooth inside
`diameter 56 of cylindrical collar 34 slides over the flared
`open segmented jaws 30. As cylindrical collar 34 is
`advanced farther in the direction of arrow 54, inside diam-
`eter 56 engages and forces segmented jaws 30 from their
`open state to converge toward an axial center line of
`cylindrical body 24 into a closed state. The convergence of
`segmented jaws 30 into the stent-catheter assembly com-
`presses stent 10 onto balloon 14.
`Cavity 58 is formed when segmented jaws 30 converge
`and completely engage the stent-catheter assembly. Cavity
`58 is partially formed by the collective convergence of
`grooves 38. FIG. 6 shows this condition in which segmented
`jaws 30 have assumed their closed state and cylindrical
`collar 34 has been advanced fully forward on cylindrical
`body 24. As seen in FIG. 6, bore 42 is needed to accom-
`modate longer catheters in which the balloon sits farther
`back.
`
`The stent-catheter assembly can be released by unscrew-
`ing cylindrical collar 34 from cylindrical body 24. This
`action disengages leading edge 36 from contact with seg-
`mented jaws 30 which are preferably biased to flare outward.
`Segmented jaws 30 then return to their flared open state thus
`releasing the stent-catheter assembly permitting removal
`thereof.
`
`invention
`the present
`If the crimp is not satisfactory,
`process can be repeated for as many times as necessary to
`achieve a tight, uniform crimp. As seen here, the operation
`of stent crimping tool 22 is simple, repeatable, and can be
`controlled precisely. In fact, with the rotating motion of
`cylindrical collar 34, it is possible to mark cylindrical body
`24 to indicate the amount of forward advancement translat-
`
`ing to the amount of convergence in segmented jaws 30
`thereby accurately crimping stent 10. To ensure accuracy,
`FIG. 6 depicts optional indicator mark 60 to help the user
`control the amount of advancement of cylindrical collar 34
`and the associated amount of convergence of segmented
`jaws 30 during the crimping operation.
`the
`As will be appreciated by those skilled in the art,
`present invention stent crimping tool 22 is designed both for
`single use applications in a cath lab by a physician, or for
`multiple use applications in a sterile environment in a high
`volume manufacturing facility. In the manufacturing facility
`where sterile conditions exist, stent crimping tool 22 can be
`used repeatedly to crimp stents onto balloon catheters until
`the mechanism wears out. Thus, repeated uses of the present
`invention are contemplated for controlled, sterile environ-
`ments although single use applications are required when
`used by cath lab personnel.
`The present invention stent crimping tool can be used
`with any stent that is released without a delivery system. The
`crimping tool may also be sold alone because its design is
`robust enough to undergo many uses. The present invention
`crimping tool 22 can be used to crimp any expandable stent
`onto any catheter, and is particularly suitable for stents
`implanted in the coronary arteries, arteries, veins, and other
`body lumens, and also is suitable to crimp saphenous vein
`grafts.
`In a preferred embodiment, all parts of stent crimping tool
`22 are made from machined polymers. On the other hand,
`the present invention is also well suited to be made from
`surgical steel, aluminum, or other metals, where it can be
`used and reused.
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`In an alternative embodiment, the grooves of the seg-
`mented jaws and the jaws themselves can be coated with
`rubber or other resilient materials. In addition,
`in other
`alternative embodiments, the grooves and/or the segmented
`jaws can include floating heads, foam plates, or a lining in
`order to effect a desired outside diameter or a specific profile
`for the stent. For the same effect, a lining may also be used
`to cover the stent and catheter prior to crimping.
`The split in cylindrical body 24 at collet end 28 can be
`achieved by using a band saw or rotating blade type tool
`wherein the natural reaction of the polymer base material is
`to bias the segmented jaws outward into a flared configu-
`ration. It is also possible through processes known in the art
`to heat treat the polymer to create the outward bias of the
`flared segmented jaws.
`Other modifications can be made to the present invention
`without departing from the scope thereof. The specific
`dimensions, procedural steps, and materials of construction
`are provided as examples, and substitutes are readily con-
`templated which do not depart from the invention.
`What is claimed is:
`
`1. A combination tool for crimping a stent onto a catheter
`and the stent, the combination comprising:
`the tool having a cylindrical body having a gripping end
`and a collet end, wherein the cylindrical body at the
`collet end transitions into a plurality of segmented jaws
`that are flared outward to receive the stent therein;
`external
`threads disposed on the cylindrical body in
`between the collet end and the gripping end;
`a collar rotatably mounted on the cylindrical body having
`an internal
`threaded opening engaging the external
`threads on the body and a front inside diameter of the
`internal threaded opening engages the plurality of seg-
`mented jaws;
`wherein advancing the collar along the threads translates
`the front inside diameter over the segmented jaws to
`converge the segmented jaws into a closed state; and
`a groove formed along a length of each jaw engaging the
`stent, wherein when the plurality of segmented jaws are
`in the closed state,
`the grooves collectively form a
`cylindrical cavity leading to an opening at the collet
`end of the cylindrical body;
`whereby closing the segmented jaws onto the stent
`mounted on the catheter, when the stent and catheter are
`situated within the cavity, crimps the stent onto the
`catheter.
`
`2. The combination according to claim 1, wherein the tool
`includes four segmented jaws and each segmented jaw
`includes a generally quarter-tubular wall cross-sectional
`shape.
`3. The combination according to claim 1, wherein the
`groove formed along each segmented jaw includes a lining.
`4. The combination according to claim 1, wherein the
`collar includes an annular cross-sectional shape.
`5. The combination according to claim 1, wherein the
`collar includes a segment that has a smooth inside diameter.
`6. The combination according to claim 1, wherein the
`cylindrical body includes a metallic material.
`7. The combination according to claim 1, wherein the
`collet end is rounded.
`
`8. The combination according to claim 1, wherein the
`segmented jaws include a coating of material on at least a
`portion thereof.
`9. The combination according to claim 1, wherein the
`plurality of segmented jaws of the cylindrical body include
`a polymer.
`
`Page 7 of 8
`
`Page 7 of 8
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`

`

`US 6,167,605 B1
`
`9
`10. Acombination tool for crimping a stent onto a catheter
`and the stent, the combination comprising:
`the tool having a cylindrical body having a gripping