United States Patent [19]
`Verbeek
`
`[54] DEVICE AND METHOD FOR MOUNTING
`STENTS
`
`[75] Inventor: Marcel A.E. Verbeek, Heerlen,
`Netherlands
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`-
`-
`e
`-
`-
`-
`[73] Assignee: Medtronic, Inc., Minneapolis, Minn.
`
`US005951540A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,951,540
`Sep. 14, 1999
`
`5,476,506 12/1995 Lunn ........................................... 623/1
`5,571,540 11/1996 Weyenberg et al.
`. 425/343
`5,626,604 5/1997 Cottone, Jr. ........
`. 606/198
`5,630,830 5/1997 Verbeek ......
`... 606/198
`5,672,169 9/1997 Verbeek ...................................... 606/1
`5,681,346 10/1997 Orth et al. .............................. 606/198
`5,693,066 12/1997 Rupp et al. ............................. 606/198
`5,725,519 3/1998 Penner et al. ...
`. 606/198
`5,738,674 4/1998 Williams et al. ........................... 606/1
`5,785,715 7/1998 Schatz ............
`... 606/108
`5,810,838 9/1998 Solar ...
`... 606/108
`
`[21] Appl. No.: 09/176,968
`-
`[22] Filed:
`Oct. 22, 1998
`[51] Int. Cl." … A61B 1700 Primary Examiner—Michael Buiz
`
`
`[52] U.S. Cl. … 6061 Assistant Examiner—Kevin Truong
`[58] Field of Search ................................ 606/1, 198, 194, †† i. º W. Raasch; Dianne
`606/192, 195, 108; 623/1, 12
`unkell Launam; Harold K. Pallon
`[57]
`ABSTRACT
`Crimping sleeves, devices and methods of crimping stents
`onto delivery devices are disclosed. The stent is located
`within a channel formed by a crimping sleeve including a set
`of crimping elements located about the channel. The crimp
`ing elements are connected by rotatable links such that
`compressing at least two opposing crimping elements
`together results in a reduction in the diameter of the channel
`and crimping of a stent located therein on a delivery device
`located therein.
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`1/1972 Berger et al. ........................... 156/180
`3,637,447
`1/1975 Green ................................. 29/203 DT
`3,862,482
`4,515,550 5/1985 Miller.
`4,655,064 4/1987 Hoback.
`4,825,682 5/1989 Orav et al. .
`4,886,062 12/1989 Wiktor .
`5,138,864 8/1992 Tarpill.
`5,314,464 5/1994 Knight et al. ........................... 607/132
`5,437,083 8/1995 Williams et al.
`.... 606/1
`5,458,581. 10/1995 Hull ........................................ 604/248
`
`20 Claims, 6 Drawing Sheets
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`30c
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`EDWARDS LIFESCIENCES EX. 1017
`Edwards Lifesciences v. Boston Scientific Scimed
`U.S. Patent No. 6,915,560
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`U.S. Patent
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`Sep. 14, 1999
`Sep. 14,1999
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`1
`DEVICE AND METHOD FOR MOUNTING
`STENTS
`FIELD OF THE INVENTION
`The present invention relates to methods and devices for
`mounting intravascular stent implants on delivery devices.
`More particularly, the present invention relates to methods
`and devices for crimping intravascular stent implants on
`delivery devices.
`BACKGROUND OF THE INVENTION
`Percutaneous transluminal coronary angioplasty (PTCA)
`is used to increase the lumen diameter of a coronary artery
`partially or totally obstructed by a build-up of cholesterol
`fats or atherosclerotic plaque. Typically a first guidewire of
`about 0.038 inches in diameter is steered through the vas
`cular system to the site of therapy. A guiding catheter, for
`example, can then be advanced over the first guidewire to a
`point just proximal of the stenosis. The first guidewire is
`then removed. A balloon catheter on a smaller 0.014 inch
`diameter second guidewire is advanced within the guiding
`catheter to a point just proximal of the stenosis. The second
`guidewire is advanced into the stenosis, followed by the
`balloon on the distal end of the catheter. The balloon is
`inflated causing the site of the stenosis to widen. The
`dilatation of the occlusion, however, can form flaps, fissures
`and dissections which threaten reclosure of the dilated vessel
`or even perforations in the vessel wall. Implantation of a
`metal stent can provide support for such flaps and dissec
`tions and thereby prevent reclosure of the vessel or provide
`a patch repair for a perforated vessel wall until corrective
`surgery can be performed. It has also been shown that the
`use of intravascular stents can measurably decrease the
`incidence of restenosis after angioplasty thereby reducing
`the likelihood that a secondary angioplasty procedure or a
`surgical bypass operation will be necessary.
`An implanted prosthesis such as a stent can preclude
`additional procedures and maintain vascular patency by
`mechanically supporting dilated vessels to prevent vessel
`reclosure. Stents can also be used to repair aneurysms, to
`support artificial vessels as liners of vessels or to repair
`dissections. Stents are suited to the treatment of any body
`lumen, including the vas deferens, ducts of the gallbladder,
`prostate gland, trachea, bronchus and liver. The body lumens
`range in diameter from small coronary vessels of 3 mm or
`less to 28 mm in the aortic vessel. The invention applies to
`acute and chronic closure or reclosure of body lumens.
`A typical stent is a cylindrically shaped wire formed
`device intended to act as a permanent prosthesis. A typical
`stent ranges from 5 mm to 50 mm in length. A stent is
`deployed in a body lumen from a radially compressed
`configuration into a radially expanded configuration which
`allows it to contact and support a body lumen. Many stents
`are designed to be expanded by the use of an expansion
`device within a body lumen. As a result, the stents are
`typically manufactured from materials that are plastically
`deformable. A plastically deformable stent can be implanted
`during a single angioplasty procedure by using a balloon
`catheter bearing a stent which has been crimped onto the
`balloon. The stent expands radially as the balloon is inflated,
`forcing the stent into contact with the interior of the body
`lumen thereby forming a supporting relationship with the
`vessel walls. After deployment, the biocompatible metal
`stent props open blocked coronary arteries, keeping them
`from reclosing after balloon angioplasty.
`The problems facing those attempting to crimp stents onto
`expandable delivery devices, such as balloon catheters, are
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`numerous. In some instances, the stents are manually
`crimped onto the delivery device using finger pressure or
`pliers. Such crimping can however, result in damage to the
`stent during handling prior to use as well as during the act
`of crimping because of the lack of control over the forces
`used during crimping. In either case, the damaged stents
`cannot be used. Furthermore, if the damage to the stent is not
`noticed, the stent may fail to perform as intended after
`deployment. In addition to damage to the stent itself before
`or during crimping, the crimping process can damage the
`delivery device if the forces applied during crimping are
`excessive.
`Even if the stent and/or the delivery device are not
`damaged, other potential problems remain. For example, the
`stent may be non-uniformly crimped onto the delivery
`device which can cause problems during advancement of the
`stent to the desired location within a body lumen and/or
`during deployment of the stent.
`Other problems include maintaining sterility of the stent.
`To assist with maintaining sterility, it is often preferred that
`the crimping devices be disposable such that they can be
`discarded after a single use. By disposing of the crimping
`device, the chance of cross-contamination originating with
`the crimping device itself can be eliminated.
`Examples of crimping devices for stents are known, such
`as U.S. Pat. No. 5,626,604 to Cottone, Jr. which discloses a
`stent crimping device including a collet for radially crimping
`a stent onto a catheter. The collet includes radially com
`pressible members that are compressed by use of sliding
`collet or a rotating collet.
`U.S. Pat. No. 5,672,169 to Verbeek discloses a manual
`stent crimping device in which the stent is mounted between
`four comer blocks, with the upper and lower pairs of comer
`blocks being separated by compressible members. Compres
`sion of the upper and lower pairs of comer blocks forces the
`stent diameter to decrease, thereby crimping the stent onto
`a delivery device extending through the stent.
`SUMMARY OF THE INVENTION
`The present invention provides devices and methods of
`crimping stents onto delivery devices. In the preferred
`crimping devices, the stent is located within a channel
`formed by a crimping sleeve including a set of crimping
`elements located about the channel. The crimping elements
`are connected by rotatable links such that application of
`force to opposing crimping elements results in equal force
`being applied simultaneously by all of the crimping ele
`ments. As a result, the crimping device may be used to crimp
`stents onto delivery devices have a range of profiles. In
`addition, in some embodiments including a compression
`apparatus, the force used to crimp the stent can be easily and
`accurately controlled to provide increased uniformity in the
`crimping process.
`The crimping device can be reusable and designed for
`operation in a manufacturing facility or closer to the point
`of-use. It may be desirable that the crimping device act as a
`storage device for a stent before use in addition to crimping
`the stent onto a desired delivery device. If so provided, the
`crimping device and enclosed stent can be supplied as a
`single sterile unit with the crimping device being discarded
`after crimping.
`In one aspect, the present invention provides a device for
`crimping a stent onto a catheter delivery system, the device
`including a generally tubular channel having a first, uncom
`pressed diameter and a second, compressed diameter, the
`channel defining a longitudinal axis; a set of
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`circumferentially-adjacent crimping elements located about
`the channel, each crimping element having a crimping
`surface defining a portion of the channel; a radial slot located
`between each pair of circumferentially-adjacent crimping
`elements; an offset slot located between each pair of
`circumferentially-adjacent crimping elements; a link located
`between the radial slot and the offset slot separating each
`pair of the circumferentially-adjacent crimping elements, the
`link having an inner end rotatably connected to one of the
`crimping elements in the pair of circumferentially-adjacent
`crimping elements and an outer end rotatably connected to
`the other crimping element in the pair of circumferentially
`adjacent crimping elements; wherein motion of one crimp
`ing element inwardly towards the longitudinal axis causes
`all of the crimping elements in the set of crimping elements
`to move inwardly towards the channel, and further wherein
`the channel is compressed from the uncompressed diameter
`to the compressed diameter
`In other aspects, the crimping devices may include one or
`more of the following features or characteristics: the set of
`crimping elements may be biased outwardly from the tubu
`lar channel; the set of crimping elements may include four
`crimping elements; and the radial slot may include an inner
`portion extending radially away from the tubular channel
`with the link aligned with the inner portion of the radial slot.
`The crimping device may also include a plurality of sets
`of crimping elements located along the channel and the
`plurality of the sets of crimping elements may be connected
`to each other, wherein inward motion of one of the sets of
`crimping elements causes inward motion of the adjacent set
`of crimping elements.
`The device may further include a compression apparatus
`acting on at least one of the crimping elements, the com
`pression apparatus capable of forcing the at least one crimp
`ing element inwardly towards the longitudinal axis. The
`compression apparatus may be capable of acting on two
`opposing crimping elements simultaneously, or it may be
`capable of acting on each of the crimping elements in the set
`of crimping elements simultaneously. The compression
`apparatus may include a compression chamber containing
`the set of crimping elements and compression fluid and it
`may also include a compressor. Alternatively, the compres
`sion apparatus may include at least one bladder for each of
`the crimping elements in the set of crimping elements.
`Further, the compression apparatus may include a pair of
`handles adapted for manual compression.
`In another aspect, the present invention provides a com
`bination comprising a stent and a crimping device, the
`crimping device including a generally tubular channel con
`taining the stent, the channel having a first, uncompressed
`diameter and a second, compressed diameter, the channel
`defining a longitudinal axis; a set of circumferentially
`adjacent crimping elements located about the channel, each
`crimping element having a crimping surface defining a
`portion of the channel; a radial slot located between each
`pair of circumferentially-adjacent crimping elements; an
`offset slot located between each pair of circumferentially
`adjacent crimping elements; a link located between the
`radial slot and the offset slot separating each pair of the
`circumferentially-adjacent crimping elements, the link hav
`ing an inner end rotatably connected to one of the crimping
`elements in the pair of circumferentially-adjacent crimping
`elements and an outer end rotatably connected to the other
`crimping element in the pair of circumferentially-adjacent
`crimping elements; wherein motion of one crimping element
`inwardly towards the longitudinal axis causes all of the
`crimping elements in the set of crimping elements to move
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`4
`inwardly towards the channel, and further wherein the
`channel and the stent are compressed from the uncom
`pressed diameter to the compressed diameter.
`In another aspect, the present invention provides a method
`of crimping a stent onto a delivery device by providing a
`crimping device containing a stent, the crimping device
`including a generally tubular channel containing the stent,
`the channel having a first, uncompressed diameter and a
`second, compressed diameter, the channel defining a longi
`tudinal axis; a set of circumferentially-adjacent crimping
`elements located about the channel, each crimping element
`having a crimping surface defining a portion of the channel;
`a radial slot located between each pair of circumferentially
`adjacent crimping elements; an offset slot located between
`each pair of circumferentially-adjacent crimping elements; a
`link located between the radial slot and the offset slot
`separating each pair of the circumferentially-adjacent crimp
`ing elements, the link having an inner end rotatably con
`nected to one of the crimping elements in the pair of
`circumferentially-adjacent crimping elements and an outer
`end rotatably connected to the other crimping element in the
`pair of circumferentially-adjacent crimping elements; locat
`ing a delivery device within the channel, at least a portion of
`the delivery device being located within the stent; moving at
`least one of the crimping elements towards the longitudinal
`axis, wherein the channel and the stent are compressed
`against the delivery device.
`As used in connection with the present invention,
`“crimping,” refers to the plastic deformation caused by
`reducing the diameter of a stent from a first, uncompressed
`diameter to a second, compressed diameter;
`“delivery device” refers to any device useful in the
`delivery of the stent to a desired location within a body
`lumen, the delivery device will typically be expandable
`with one specific example of a delivery device being a
`balloon catheter;
`“longitudinal axis” refers to an imaginary line extending
`through the center of the tubular channel in which a
`stent is located during the crimping process;
`“circumferentially-adjacent crimping elements” are
`crimping elements adjacent to each other when moving
`about the circumference of the crimping device;
`“biased” in a direction means that the device will, in the
`absence of outside forces, assume a particular position.
`These and other features and advantages of the present
`invention are discussed below with respect to various
`illustrative embodiments of the invention.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective view of one crimping device
`according to the present invention;
`FIG. 2 is an end view of the device of FIG. 1;
`FIG. 3 is a partial exploded view of another crimping
`device according to the present invention;
`FIG. 4 is an end view of the crimping device of FIG. 3;
`FIG. 5 is an end view of another crimping device accord
`ing to the present invention with the tubular channel in the
`uncompressed diameter;
`FIG. 6 is an end view of the crimping device of FIG. 5
`with the tubular channel in the compressed diameter;
`FIG. 7 is an end view of another crimping device includ
`ing a compression apparatus;
`FIG. 8 is an end view of another crimping device includ
`ing another compression apparatus;
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`FIG. 9 is a partial cross-sectional view of another crimp
`ing device including another compression apparatus; and
`FIG. 10 is a perspective view of another crimping device
`including a stent and delivery device on which the stent is to
`be mounted.
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`DETAILED DESCRIPTION OF ILLUSTRATIVE
`EMBODIMENTS
`The present invention provides a device useful for crimp
`ing stents onto a delivery device. FIGS. 1 and 2 illustrate one
`crimping sleeve 10 according to the present invention. The
`sleeve 10 includes a generally tubular channel 20 having an
`opening in the first end 12 of the sleeve 10. The channel 20
`preferably defines a longitudinal axis 22 extending through
`the center of the channel 20 along its length.
`It is preferred, but not required, that the tubular channel 20
`extend completely through the sleeve 10 from the first end
`12 to the second end 14. By extending the tubular channel
`completely through the sleeve 10, a catheter or other deliv
`ery device may be more easily located within the channel 20
`during the crimping process.
`As seen at the first end 12 of the sleeve 10, a set of
`circumferentially-adjacent crimping elements 30a, 30b, 30c
`and 30d (referred to generally as crimping elements 30
`below) are located about the channel 20. Each of the
`crimping elements 30a—d includes a crimping surface
`32a–d, respectively, that collectively define the channel 20
`formed in crimping sleeve 10.
`Referring now to the pair of circumferentially-adjacent
`crimping elements 30a and 30b, the connection between
`each pair of circumferentially-adjacent crimping elements
`30 will now be described. A pair of slots 44a and 48a are
`formed in the sleeve 10. Radial slot 44a preferably extends
`radially from the tubular channel 20. One end of the radial
`slot 44a opens into the channel 20 and defines one edge of
`the crimping surface 32a and an opposing edge of crimping
`surface 32b. It is preferred that the radial slot 44a not extend
`to the outer perimeter of the sleeve 10.
`Offset slot 48a is slightly offset circumferentially from the
`radial slot 44a and opens to the exterior of the sleeve 10 as
`seen in FIG. 1 (where both offset slots 48a and 48d are
`illustrated). The radial slot 44a and offset slot 48a form a
`link 40a that extends from the outer end of the radial slot 44a
`to the inner end of the offset slot 48a.
`The link 40a is rotatably connected to crimping element
`30b at inner end 43a and the outer end 45a is connected to
`crimping element 30a as indicated in FIG. 2. It is preferred
`that the connections between the link 40a and the crimping
`elements 30a/30b at both the inner end 43a and the outer end
`45a be relatively flexible and the link 40a be relatively rigid
`and incompressible. It is further preferred that, in response
`to compressive forces on the crimping sleeve 10, the link
`40a rotate about axes of rotation extending through the inner
`and outer ends 43a and 45a. The hinges 43a and 45a and
`their corresponding axes of rotation preferably extend par
`allel to the central longitudinal axis 22 extending through the
`tubular channel 20.
`The crimping elements 30 are preferably biased out
`wardly in the position illustrated in FIGS. 1 and 2, i.e.,
`biased outwardly such that the tubular channel 20 is in its
`first, uncompressed diameter. As the crimping sleeve 10 is
`compressed, the rotation of the link 40 about the inner and
`outer ends 43a and 45a allows the tangential width of the
`slots 44a and 48a to decrease. As illustrated in FIGS. 1 and
`2, each of the crimping elements 30a—d includes a link
`40a–d, respectively, along with the corresponding radial
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`slot, offset slot, inner hinge, and outer hinge. As a result,
`during compression of the crimping sleeve 10, the tangential
`widths of the radial slots and the offset slots all typically
`decrease. By decreasing the width of the radial and offset
`slots, the diameter of the tubular channel 20 is decreased
`from a first, uncompressed diameter to a second, compressed
`diameter. Any stent located within the channel 20 also
`experiences that compression.
`It is further preferred that, after the compressive forces are
`released, the crimping elements 30 move back outwardly
`from the longitudinal axis 22 to assist in removal of the stent
`and delivery device from the channel 20. In some instances
`the channel may return to its uncompressed diameter, but in
`other instances, some permanent deformation of the crimp
`ing sleeve 10 may have occurred during crimping.
`FIGS. 3 and 4 illustrate another crimping sleeve 110
`according to the present invention. The crimping sleeve 110
`includes a plurality of sets 150 of crimping elements 130a–d
`(collectively referred to as crimping elements 130). The sets
`150 are aligned along a longitudinal axis 122, with the sets
`150 collectively forming a tubular channel 120 in which a
`stent to be crimped can be located. The crimping elements
`130 in each of the sets 150 are constructed similar to the
`crimping elements 30 discussed with respect to FIGS. 1 and
`2 above, with the primary difference being the length or
`depth of the crimping elements 130.
`Another difference in the crimping sleeve 110 is that the
`offset slots 148 in longitudinally adjacent sets 150 (i.e., sets
`150 located next to each other along the longitudinal axis
`122) are preferably located on alternating sides of their
`respective radial slots 144. This is illustrated in FIG. 3 where
`the offset slots 148 in successive sets of crimping elements
`are not aligned with each other, as well as in FIG. 4 where
`the offset slots 148' in the successive set 150 of crimping
`elements are depicted in broken lines.
`Because alignment of the successive sets 150 of crimping
`elements 130 is desired, the illustrated sets 150 include
`alignment pins 152 and associated bores 154 that receive the
`pins 152 to maintain alignment of the crimping elements 130
`between successive sets 150. It is preferred that each crimp
`ing element 130 include two or more alignment pins 152 and
`bores 154 to prevent rotation of the crimping elements 130
`around the alignment pins 152 and bores 154 during the
`crimping process. It will be understood that many other
`mechanisms or techniques of maintaining alignment
`between the successive sets 150 of crimping elements 130
`may be substituted for the illustrated alignment pins 152 and
`bores 154. The substitutions may include, but are not limited
`to shaping the mating surfaces of the sets 150 so that they
`nest in a particular orientation or bonding the sets 150
`together during or after assembly (through the use of welds,
`adhesives, etc.).
`It is preferred, but not required, that the alignment mecha
`nism also transmit the compressive forces applied during
`crimping to the adjacent sets 150 of crimping elements 130.
`The pins 152 and bores 154 illustrated in FIG. 3 accomplish
`that function in addition to maintaining the alignment
`between crimping elements 130. By transmitting the com
`pressive forces, the alignment pins 152 and bores 154 may
`provide more uniform compression along the longitudinal
`length of the crimping sleeve 110 even if the applied forces
`are not evenly distributed along that length.
`Another crimping sleeve according to present invention is
`illustrated in FIG. 5. The sleeve 210 also includes a plurality
`(preferably four) crimping elements 230a—d (collectively
`referred to as crimping elements 230) located about a tubular
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`channel 220. The interconnection of the crimping elements
`230 will now be described with specific reference to crimp
`ing element 230a, although t will be understood that the
`construction is the same for each of the crimping elements
`230.
`Crimping element 230a is separated from its
`circumferentially-adjacent crimping elements 230b and
`230d by a radial slot 244a and an offset slot 248a. The radial
`slot 244a opens into the channel 220 and the offset slot 248a
`opens to the exterior of the crimping sleeve 210.
`A relatively rigid link 240a is located between the radial
`slot 244a and the offset slot 248a. It is preferred that the link
`240a be radially aligned with the inner portion 242a of the
`radial slot 244a as seen in FIG. 5. The link 240a is connected
`to crimping element 230a at its outer end 245a and is
`connected to crimping element 230b at its inner end 243a.
`The connections of the link 240a to crimping elements 230a
`and 230b preferably allow the link 240a to rotate about axes
`extending through the connections 243a and 245a (those
`axes extend out of the page in the view illustrated in FIG. 5).
`In other words, the connections 243a and 245a function as
`hinges, allowing the relatively rigid links (such as link 240a)
`to rotate while the crimping elements 230 are moving
`inward to compress a stent.
`During compression of the crimping sleeve, movement of
`the opposing crimping elements 230a and 230c towards
`each other (see FIG. 6) causes corresponding inward motion
`of the intervening crimping element 230b and 230d because
`of the hinged or rotatable connections between the crimping
`elements 230 provided by the links as discussed above. In
`addition, the forces applied to the opposing crimping ele
`ments 230a and 230c is also distributed by the hinged link
`connections.
`The results of the rotation of the links includes the
`narrowing of the inner portion 242a of the radial slot 244a
`which, in FIG. 6, is depicted as being entirely closed. It will
`be understood that the inner portions of the radial slots may,
`in some instances, not be entirely closed during crimping.
`Furthermore, it should be understood that the inner portions
`of the radial slots may not close uniformly, i.e., one or more
`of the slots may have different tangential widths as the
`crimping sleeve 210 conforms to the profile of the delivery
`device on which the stent is being mounted.
`One advantage of the crimping sleeve 210 over the other
`embodiments described above is that the tangential width of
`the inner portion 242a of the radial slot 244a can typically
`be narrower that the corresponding width of the radial slots
`44/144 in the crimping sleeves 10/110. That narrower width
`assists in reducing the likelihood that struts on a stent
`inserted into the tubular channel 220 can be caught in the
`inner portion 242a of the radial slot 242a and damaged
`during crimping.
`In addition to the crimping devices described above, the
`crimping devices according to the present invention may
`also include a compression apparatus used in compressing
`the crimping sleeve. FIGS. 7–9 depict various illustrative
`crimping devices including compression apparatus in accor
`dance with the present invention. Although the crimping
`devices described above can be compressed manually (using
`finger pressure), it may be desirable to use a compression
`apparatus that can allow for more precise control of the
`crimping forces. Control over the crimping forces can result
`in more reliable crimping of stents on delivery devices.
`FIG. 7 illustrates one crimping device 300 including a
`compression apparatus in the form of a chamber 360 and
`plunger 362 with a crimping sleeve 310 located within the
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`5,951,540
`
`8
`chamber 360. The plunger 362 can be extended downward,
`causing the opposing crimping elements 330a—d in the
`sleeve 310 to move towards each other, thereby reducing the
`diameter of the tubular channel 320. It is preferred that the
`plunger 362 be driven hydraulically by fluid pressure sup
`plied through line 364, although alternative techniques of
`providing for motion of the plunger 362 are also envisioned.
`One alternative could include, e.g., an electromagnetically
`driven plunger. Regardless of the source of the driving force,
`it is preferred that it be controllable with respect to magni
`tude.
`FIG. 8 illustrates another crimping device 400 including
`an alternative compression apparatus including a series of
`bladders 470a-d (collectively referred to as bladders 470)
`located about a crimping sleeve 410. Each bladder 470 is
`located between an outer wall 472 and one of the crimping
`elements 430a–d. As a result, inflation of the bladders 470
`by a fluid source (not shown) causes the crimping elements
`430a—d to move inwardly, compressing the tubular channel
`420. One advantage of the compression apparatus illustrated
`in FIG. 8 is that the inflation pressures of the bladders 470
`can be balanced such that the force on each of the crimping
`elements 430a—d is also balanced. This force-balancing may
`improve the uniformity of the crimping process.
`FIG. 9 illustrates another crimping device 500 including
`a compression apparatus in which the crimping sleeve 510
`including crimping elements 530a—d is located within a
`pressure chamber 580. The compression apparatus includes
`a pressure source 582 in fluid communication with the
`pressure chamber 580. Because the crimping sleeve 510 is
`located within a single chamber 580, the forces applied to
`each of the crimping elements 530a—d of the sleeve 510 will
`be balanced.
`FIG. 9 also depicts one actuator for providing the pressure
`from source 582 in the form of a pair of handles 584 that can
`be moved together, causing a plunger 586 to act on the
`source 582. Because this compression apparatus includes
`manual input, it may be preferred to supply a gauge 588 as
`shown to allow monitoring of the fluid pressure and, as a
`result, the forces applied to the crimping sleeve 510.
`FIG. 10 illustrates one crimping device 600 in which a
`portion of the device is removed to expose the stent 602
`located within the tubular channel 620. In some instances, it
`may be desirable to manufacture the crimping device 600
`separate from the stent 602 and locate the stent 602 within
`the channel 620 of the crimping device 600 after manufac
`turing. In other instances, it may be possible to manufacture
`the crimping device 600 around the stent 602 by, e.g., insert
`injection molding or other suitable techniques.
`Regardless of how manufactured, the crimping device
`600 with the stent 602 located within channel 620 are then
`provided for insertion of a delivery device 604 into the
`channel 620. Because the stent 602 is already located within
`the channel 620, the delivery device 604 is also located
`within the stent 602 when in channel 620. To assist in
`positioning of the delivery device 604, it may be desirable
`to provide a crimping device 600 that is translucent or
`tra