United States Patent
`[19]
`[11] Patent Number:
`6,096,027
`
`Layne
`[45] Date of Patent:
`Aug. 1, 2000
`
`U5006096027A
`
`[54] BAG ENCLOSED STENT LOADING
`APPARATUS
`
`[75]
`
`Inventor: Richard Layne, Phoenix, AriZ.
`
`5,725,519
`5,733,325
`5,738,674
`
`............................... 606/1
`3/1998 Penner et al.
`3/1998 Robinson et al.
`.......................... 623/1
`4/1998 Williams et al.
`
`.
`
`5,749,921
`5,800,517
`
`.............................. 623/1
`5/1998 Lenker et al.
`9/1998 Anderson et al.
`.......................... 623/1
`
`[73] Assignee:
`
`Impra, Inc., a subsidiary of C.R.
`Bards Inca TemPe> AM
`
`9/1998 Morales .................................. 606/198
`5,810,873
`FOREIGN PATENT DOCUMENTS
`
`[21] Appl. No; 09/310,763
`
`[22]
`
`Filed:
`
`May 12, 1999
`
`Related US. Application Data
`Prov1s1onal application No. 60/102,404, Sep. 30, 1998.
`[60]
`Int. Cl.7 ..................................................... A61B 17/00
`[51]
`[52] US. Cl.
`606/1' 606/108' 606/198
`
`[58] Field 0f Search
`’ 606/1 108 106
`606/109192194195 198’ 200’ 209?
`’
`’
`’
`’
`’ 623/1 12’
`’
`
`[56]
`
`References Cited
`
`623/1
`
`U.S. PATENT DOCUMENTS
`.
`.
`3’328’33; 1:13; gig—615M111 '
`4,943,297
`7/1990 Saveliev maul”, iiiiiiiiiiiiiiiiiiiiiiiiiiii
`7
`7
`5,382,260
`1/1995 Dormandy, Jr. et al.
`.
`5,591,222
`1/1997 Susawa et al.
`.............................. 623/1
`5,626,604
`5/1997 Cottone, Jr.
`.
`5,630,830
`5/1997 Verbeek.
`576497950
`7/1997 Bourne 6t a1~ -
`giggiiég? 13133;
`IVerbeek '
`,
`,
`noue .
`5,683,451
`11/1997 Lenker et al.
`5,693,066
`12/1997 Rupp et al.
`.
`5,693,089
`12/1997 Inoue .......................................... 623/1
`
`.
`
`WO 98/20812
`
`5/1998 WIPO .
`
`Primary Examiner—Jeffrey A. Smith
`Assistant Examiner—Eduardo C. Robert
`
`Attorney, Agent, or Firm—Graham & James LLP
`[57]
`ABSTRACT
`
`.
`.
`An apparatus for loading a stent onto or into a catheter. A
`flexible sterile sleeve is provided to encase the stent as it is
`pulled through a loading device. The loading device is a
`simple design utilizing a tapered passageway. The passage-
`way has first diameter at a proximal end which tapers to a
`second diameter, forming a funnel. The passageway contin-
`ues at the second diameter forming a tube. The sleeved stent
`is pulled through the loading device from the proximal end
`to the distal end, smoothly compressing the stent. Depending
`on the type of stent and catheter being used, the stent is
`either crimped onto the catheter as it is pulled through the
`funnel, or is loaded into a catheter ositioned at the distal
`P
`end of the loading device. The sleeve acts to minimize the
`frictional forces to which the stent
`is subjected and to
`eliminate the longitudinal force that
`the stent would be
`subjected to if pushed or pulled directly. The sleeve may be
`close-ended to provide an additional sterility barrier about
`the Stem'
`
`15 Claims, 4 Drawing Sheets
`
`I..,.
`
`
`
`".,a.nioiiifi1,157.73.1.,.
`
`
`70
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`
`
`~..1 ’
`
`26'
`
`Edwards Lifesciences v. Boston Scientific
`
`IPR2017-00444 EX. 2028
`
`US. Patent N0. 6,915,560
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`US. Patent
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`Aug. 1, 2000
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`Sheet 4 0f 4
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`6,096,027
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`1
`BAG ENCLOSED STENT LOADING
`APPARATUS
`
`The present application is a continuation-in-part of US.
`Provisional Application No. 60/102,404 filed on Sep. 30,
`1998. Priority is claimed from that application which appli-
`cation is incorporated herein by reference.
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates generally to the field of
`medical devices, and more particularly, to devices for load-
`ing stents onto or into a catheter for use in a medical
`procedure.
`2. Description of Related Art
`Stents and similar endoluminal devices are currently used
`by medical practitioners to treat vessels that become nar-
`rowed so that flow through the vessels is restricted. This
`problem arises, for example, as a result of the disease
`process known as arteriosclerosis or after an angioplasty of
`a coronary artery to correct arteriosclerosis when excess
`tissue proliferation blocks the newly opened vessel. Stents
`can also be used to reinforce collapsed or narrowed tubular
`structures in the respiratory system, the reproductive system,
`biliary ducts or any other tubular body lumen. A procedure
`for inserting stents often involves first passing a guide wire
`through the affected area of the lumen. A catheter is then
`inserted over the guide wire and advanced to the site. The
`stent is inserted either simultaneously with the catheter (e.g.,
`is present on the tip of the catheter) or immediately follow-
`ing insertion of the catheter (e.g.,
`is passed through the
`catheter).
`In many cases, an angioplasty balloon catheter will be
`advanced to the affected site. The balloon is then inflated,
`compressing the growth or material causing the narrowing.
`A stent is then inserted into the compressed area to prevent
`restenosis of the vessel. In some cases a balloon catheter
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`with a metal stent crimped over the balloon is used. This
`device is inserted into the affected site and the balloon
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`40
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`to its full size and
`thereby enlarging the stent
`inflated,
`compressing the growth. Still another variation is placing a
`compressed self-expanding stent inside a catheter. After the
`catheter is advanced to the affected site, the stent is released
`from the catheter, whereupon it expands to its full size.
`Whichever method is used,
`the stent must
`first be
`“loaded” onto or into the delivery catheter. One common
`way of accomplishing this is for the physician to hand crimp
`the stent over the end of a balloon catheter. The physician
`selects the appropriate size and type of stent and manually
`deforms it with his or her fingers to crimp it over the balloon
`prior to insertion of the balloon catheter into the patient. This
`procedure is not optimal because there is a lack of unifor-
`mity in the crimping process. The stent may either be
`inadequately compressed or be excessively compressed so
`that
`it
`is mechanically damaged. In addition,
`traditional
`loading methods potentially subject the stent to contamina-
`tion.
`
`Many prior art solutions to the problems of stent com-
`pression have involved the use of tapering passageways or
`“funnels”. The stent is inserted into the funnel in an enlarged
`state and is pulled or pushed through the funnel, compress-
`ing the stent onto a balloon catheter which has been inserted
`inside the small end of the funnel. US. Pat. No. 5,693,089
`to Inoue discloses one such device. In this reference, a stent
`is crimped onto a balloon catheter by pulling the stent
`through the funnel. The disadvantage to this approach is that
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`2
`pushing or pulling a sometimes fragile stent onto a delivery
`device will distort and/or permanently damage the stent.
`Another example is shown in US. Pat. No. 5,725,519 to
`Penner et al. which discloses loading a stent onto a balloon
`catheter by means of a two piece device which employs a
`funnel-shaped bore to compress the stent. The Penner et al.
`device incorporates an open-ended flexible tube to surround
`the stent. While Penner addresses the need for uniformity in
`compressing stents,
`it
`is intended to crimp stents onto
`balloon catheters and cannot be used to load stents into
`
`catheters. Further, it does not contemplate an embodiment to
`completely enclose and protect
`the sterility of a stent.
`Therefore, it is desirable to provide a loading device for
`stents that would uniformly compress or crimp a stent onto
`or into a catheter while minimizing manipulation of the stent
`prior to the crimping process.
`
`SUMMARY OF THE INVENTION
`
`The present invention compresses and loads stents onto or
`into a catheter by using either an open-ended sleeve to
`prevent stress to the stent or a closed-end bag prevent stress
`and preserve sterilely.
`It is an object of this invention to minimize the frictional
`(shear) forces acting on the wall of a stent during the process
`of loading a stent onto or into a catheter.
`It is a further object of the present invention to provide a
`procedure for crimping a stent onto or into a catheter while
`maintaining stent sterility.
`These and additional objects are accomplished using
`either an open-ended sleeve or a close-ended sleeve (“bag”)
`and a loading device. First, a full-sized stent is placed into
`a flexible sleeve (either open or close-ended). This step is
`contemplated to be carried out by the manufacturer. The
`enclosed stent would be inserted into sterile packaging and
`subjected to routine sterilization procedures (e.g., radiation
`or chemical sterilization). Alternatively, sterile sleeves can
`be provided for “field loading” of the stent. The sleeve or
`bag can consist of many different materials, such as
`polyethylene, polytetrafluoroethylene (“PTFE”) or espe-
`cially expanded polytetrafluoroethylene (“ePTFE”). The bag
`may be advantageously treated with various coatings to
`lubricate passage of the stent through the funnel. In the case
`of an open-ended sleeve, the inner surface is advantageously
`coated with a biocompatible “tacky” coating to enhance
`friction between the sleeve and the stent. Typically,
`the
`sleeve or bag is longer than the stent so that the end of the
`bag or sleeve can be threaded through the small orifice of the
`loading device and grasped. The catheter to be loaded is then
`placed into the loading device so that the distal end of the
`catheter lies near the proximal (small) orifice of the funnel-
`shaped loading device. The sterile outer packaging material
`is opened, and the bag with the stent inside is then inserted
`over the catheter end and the bag and stent are simulta-
`neously pulled through the loading device from large orifice
`to small orifice. This results in a catheter with a stent
`
`uniformly compressed onto its end and with the bag over the
`end to maintain sterile conditions. Although the loading
`procedure normally takes place in a sterile operating
`environment, the sleeve provides an additional barrier to
`guarantee stent sterility. Even an open ended sleeve provided
`significant protection against contamination. Because the
`stent is left in the patient indefinitely, even a single patho-
`genic organism might cause serious complications. Imme-
`diately before the stent is inserted into the patient, the bag
`can be removed. Removal of the bag or sleeve can consist
`of sliding it back off of the device, or tearing it off using a
`
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`6,096,027
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`3
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`tear strip (e.g., an embedded length of fiber that can be
`pulled to cut open the sheath). Also, tear away seams or
`perforations can be incorporated into the bag or sleeve for
`easy removal.
`Providing a buffer layer of sleeve material over the stent
`is beneficial in at least two ways. First, the layer acts to
`minimize the frictional forces to which the stent is subjected
`in being reduced it from full diameter. Second, by pulling the
`bag or sleeve rather than directly pushing or pulling the
`stent, the longitudinally applied force is avoided, thereby
`reducing stresses to the stent. As a result there is less chance
`of perforating any covering (e.g., an encapsulated stent) or
`of damaging the stent struts through bending or fracture.
`The loading device consists of a block of material tra-
`versed by a passageway of varying diameter (e.g., funnel-
`shaped). At the proximal end of the block, the passageway
`has its widest first diameter. This wide first diameter tapers
`down to a second smaller diameter, thereby forming a funnel
`shape. The second diameter runs throughout the remainder
`of the block forming a tubular shape. The cross-section of
`the second diameter can be circular or can be other shapes
`such as a rounded star (e.g., a star shape wherein the arms
`have rounded tips) to aid in the compression and folding of
`the bag and/or enclosed stent. The funnel-shaped passage-
`way can be produced by drilling or cutting a solid block of
`material (plastic such as an acrylic or metal such as
`aluminum). The passageway can also be produced by well-
`known methods of molding. Alternatively, the funnel-shape
`can be constructed from formed sheet metal, etc.
`This device is useful not only for loading a stent onto a
`catheter, as described above, but can also be used to load a
`stent into a catheter. In this case, the catheter is placed into
`a port at the distal end of the loading device. This port has
`a diameter larger than the second diameter and is large
`enough to accommodate a catheter designed for loading
`stents inside. The bagged stent is then pulled through the
`device and into the catheter. The bag or sleeve is pulled over
`the catheter at the same time and remains in place until the
`catheter is used on a patient. The bag or sleeve can be sealed
`(closed) at the distal end at least. If the sleeve is to be pulled
`over the catheter (rather like putting on a sock) as described
`above, then the proximal end, at least, must be left open.
`Although the sleeve may be open at both ends, it is advan-
`tageous to enclose the stent by sealing both ends to allow for
`the stent to be sterilized. Then one end can be sterilely
`opened just before compression of the stent. Alternatively,
`the bag can be split to pass over and around the end of the
`catheter. If the sleeve is to be pulled through the catheter, it
`is not necessary to even have even a single open end, and the
`bag can remain completely closed to ensure sterility.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a longitudinal-sectional view of a first embodi-
`ment of a stent loading apparatus.
`FIG. 2 is a cross-sectional view of FIG. 1 taken at 2—2.
`FIG. 3 is a cross-sectional view of an alternative embodi-
`
`ment of the stent loading device (also taken at a point
`corresponding to 2—2).
`FIG. 4 is a longitudinal-sectional view of an embodiment
`of the stent loading apparatus in the initial phases of com-
`pressing a stent onto an angioplasty balloon.
`FIG. 5 shows the device of FIG. 4 after completion of the
`stent compression.
`FIG. 6 is a longitudinal-sectional view of an additional
`embodiment of the stent loading apparatus wherein the bag
`is pulled through the catheter.
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`FIG. 7 is a longitudinal-sectional view of the embodiment
`of FIG. 1 used with an open-ended sleeve.
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`Referring now to the drawings, in which like reference
`numbers represent similar or identical structures throughout,
`FIG. 1 depicts a stent loading apparatus 10 consisting of a
`loading device 20 and a closed ended sleeve 30 (this and all
`other embodiments can be used with an open-ended sleeve
`as well). A stent 50 and a catheter 40 in which the stent 50
`is loaded are also shown. The loading device 20 is a block
`22 which has at its center a passageway of varying diameter.
`This passageway can be coated with PTFE or other low
`friction material that facilitates the movement of the bag-
`enclosed stent 50. At the proximal end of the block 22, the
`passageway has its largest diameter 26. From there the
`passageway tapers to a second diameter 28 thus forming a
`funnel shape. The second diameter 28 is constant to the
`distal end of the block, forming a tube.
`FIG. 2 shows a cross-section of the loading device 20. At
`the distal end of the block 22, the tube-like section of the
`passageway widens to a third diameter 24 to permit the
`docking of a catheter 40. Pulling the stent 50 through the
`loading device 20 compresses it from its full diameter to the
`illustrated smaller diameter. To accomplish this the stent 50
`is placed inside of the sleeve 30 prior to being pulled through
`the passageway. As mentioned above, there are advantages
`to using a sleeve 30 which is initially closed at both ends. In
`such a case one end is opened prior to the compression
`process leaving only a single closed end 34. The sleeve 30
`is pulled through the loading device 20 by extensions 32 of
`sleeve material located near the open end. As the sleeve 30
`is pulled through the loading device 20, compressing the
`stent, it is also pulled over the end of the catheter 40. The
`sleeve 30 is pulled until the stent 50 is entirely inside the
`catheter 40, where it comes in contact with a catheter
`unloading arm or plunger 44. Following loading the sleeve
`30 can remain over the end of the catheter 40 with its closed
`
`end 34 sealing the stent 50 from the outside. Of course, the
`bag 30 must be torn off prior to insertion of the catheter into
`the patient.
`The sleeve 30 can be made from any of a number of
`plastic films such as polyethylene, polyvinyl, polyurethane,
`cellulose, and PTFE. PTFE is especially preferred because it
`is “slippery”. Alternately, other plastic films can be coated
`with antifriction materials. It may also be advantageous to
`coat
`the inside surface with a slightly plastic or tacky
`composition to “grip” the stent and control the movement of
`the film relative to the stent so that forces are uniformly
`applied to the length of the stent 30 as opposed to being
`applied just by the end 34 of the bag. With an open-ended
`sleeve as shown in FIG. 7 such a “gripping” coating is
`especially important. Expanded PTFE is especially preferred
`because this material is readily permeable to air. Thus, a
`sleeve that is closed at both ends can be readily compressed
`since the air easily escapes through the ePTFE. If a closed
`sleeve of other plastic films is used, special provision must
`be made for escape of trapped air during the compression
`process.
`In the case of stents fabricated from shape memory alloy
`the passageway can advantageously be fabricated from a
`metal with circulation channels for refrigerant embedded in
`the walls of the passageway. The stent is thereby chilled
`below its transformation temperature as it is pulled through
`the device. In this case the stent may advantageously be
`pulled fairly slowly to allow complete temperature equili-
`bration.
`
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`6,096,027
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`5
`the cross-
`There are many different possibilities for
`sectional shape of the passageway of the loading device 20.
`FIG. 3 depicts a cross-section of a second embodiment of the
`invention, showing a loading device 60, with a block 62, a
`first diameter 66 and a second diameter 68.
`In this
`embodiment, however, the second diameter 68 is not round
`and is instead a rounded “star” shape. This design illustrates
`an additional way to crimp the stent 50 onto or into a catheter
`as the cross-sectional shape of the passageway promotes
`folding of the sleeve 30 and/or of the stent 50, itself. It is
`specifically contemplated that the number of lobes of the
`cross-section be related to the underlying structure of the
`stent so that folding and crimping is induced in the most
`favorable areas of the stent or encapsulated stent.
`FIG. 4 shows a third embodiment of the present invention
`comprising the loading device 20, the sleeve 30, and the
`stent 50. This embodiment is different, however, in that the
`catheter 80 is a balloon catheter. The balloon tip of the
`catheter 80 is inserted inside of the tube created by the
`second diameter 28 until the distal end of the catheter 80,
`bearing by a deflated balloon 84, is near the first diameter 26
`of the loading device 20. In FIG. 4, the stent 50 is shown in
`the process of being compressed. The sleeve 30 is pulled
`through the loading device 20 so that the stent 50 begins to
`compress around the balloon 84. At this point the end 34 of
`the sleeve 30 reaches the distal tip of the catheter 80 and both
`the stent 50 and the catheter 80 are pulled through the
`passageway so that the stent 50 is securely crimped around
`the balloon portion 84 of the catheter 80 as shown in FIG.
`5. Again, the end result is the sterile catheter 80 with the
`stent 50 loaded onto it, encased in the bag-sleeve 30. Again,
`the bag 30 is removed before the catheter 80 is used on a
`patient. As discussed above, the sleeve 30 can be removed
`in a variety of ways including pulling a pre-designed tear
`strip. The sheath 30 can be removed prior to catheter
`insertion; alternatively, it can be composed of a polymer that
`spontaneously dissolves in the aqueous milieu of the
`patient’s blood stream.
`FIG. 6 shows an alternate embodiment where the sleeve
`
`30 is pulled through the catheter. In this embodiment the
`sleeve 30 can be closed at both ends. A pull string 70 is
`attached to the proximal end of the sleeve 30 and threaded
`through the catheter. The string is then used to pull the stent
`50 into the end of the catheter 80. If the sleeve 30 is equipped
`with perforations, the pull string 70 can be used to remove
`the sleeve 30 from the stent either before or after the catheter
`
`80 is inserted into a patient.
`FIG. 7 shows the embodiment of FIG. 1 being used with
`an open-ended sleeve. All of the embodiments of the current
`invention can be used with either close or open ended
`sheaths. The stent or the inner surface of the sleeve are
`
`advantageously coated with a material like rosin to prevent
`or control slippage of the sleeve relative to the stent.
`Having thus describe a preferred embodiment of a sleeved
`stent loading apparatus, it will be apparent by those skilled
`in the art how certain advantages of the present invention
`have been achieved.
`It should also be appreciated that
`various modifications, adaptations, and alternative embodi-
`ments thereof may be made within the scope and spirit of the
`present invention. The described embodiments are to be
`considered illustrative rather than restrictive. The invention
`
`is further defined by the following claims.
`I claim:
`
`1. An apparatus for loading a catheter assembly compris-
`ing:
`a flexible sleeve that envelopes a stent placed within;
`
`6
`a loading device comprising a passageway, wherein said
`passageway tapers from a larger first diameter to a
`smaller second diameter; and
`means for pulling the flexible sleeve through the passage-
`way so that the sleeve and the stent enveloped therein
`are compressed by the passageway tapering from the
`first diameter to the second diameter.
`
`2. The apparatus described in claim 1, wherein said sleeve
`further includes a tear strip for opening the sleeve.
`3. The apparatus described in claim 1, wherein said sleeve
`further includes seams or perforations for opening the
`sleeve.
`
`4. The apparatus described in claim 1, wherein said sleeve
`further comprises a coated interior to hold said stent in
`position and a coated exterior to minimize friction.
`5. The apparatus described in claim 1, wherein a cross-
`section of said second diameter is circular.
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`6. The apparatus described in claim 1, wherein a cross-
`section of said second diameter shows a plurality of rounded
`lobes.
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`20
`
`7. The apparatus described in claim 6, wherein spacing of
`the lobes is selected to induce folding during compression of
`the stent.
`
`8. The apparatus described in claim 1, wherein said device
`further comprises an intermediate diameter at a distal end of
`said passageway which is larger than said second diameter
`but smaller than said first diameter, and wherein said inter-
`mediate diameter is sized to accommodate a catheter into
`which a stent is to be loaded.
`
`9. A method for loading a stent onto or into a catheter
`comprising:
`providing a loading device comprising a passageway,
`wherein said passageway tapers from a larger first
`diameter to a smaller second diameter;
`making a sleeved stent by placing a flexible sleeve over
`said stent;
`placing said sleeved stent into said loading device in said
`tapered portion of said passageway so that an end of the
`sleeve can be grasped from a smaller diameter end of
`the passageway;
`placing said catheter at or into the smaller diameter end of
`the passageway; and
`pulling said sleeve through the smaller diameter end of
`the passageway so that said stent is reduced in diameter
`and moved onto or into said catheter.
`10. The method described in claim 9, wherein said sleeve
`has a closed-end.
`
`11. An apparatus for loading a catheter assembly com-
`prising:
`a flexible sleeve having a closed end enveloping a stent
`placed within;
`a loading device comprising a passageway, wherein said
`passageway tapers from a larger first diameter to a
`smaller second diameter; and
`means for pulling the flexible sleeve through the passage-
`way so that the sleeve and the stent enveloped therein
`are compressed by the passageway tapering from the
`first diameter to the second diameter.
`
`12. An apparatus for loading a catheter assembly com-
`prising:
`a flexible sleeve that envelopes a stent placed within,
`wherein said sleeve further includes a tear strip for
`opening the sleeve;
`a loading device comprising a passageway, wherein said
`passageway tapers from a larger first diameter to a
`smaller second diameter; and
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`6,096,027
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`7
`means for pulling the flexible sleeve through the passage-
`way so that the sleeve and the stent enveloped therein
`are compressed by the passageway tapering from the
`first diameter to the second diameter.
`
`13. An apparatus for loading a catheter assembly com-
`prising:
`a flexible sleeve that envelopes a stent placed within;
`a loading device comprising a passageway, wherein said
`passageway tapers from a larger first diameter to a
`smaller second diameter; and
`means for pulling the flexible sleeve through the passage-
`way so that the sleeve and the stent enveloped therein
`are compressed by the passageway tapering from the
`first diameter to the second diameter, wherein a cross-
`section of said second diameter shows a plurality of
`rounded lobes.
`
`14. An apparatus for loading a catheter assembly com-
`prising:
`a flexible sleeve that envelopes a stent placed within;
`a loading device comprising a passageway, wherein said
`passageway tapers from a larger first diameter to a
`smaller second diameter; and
`means for pulling the flexible sleeve through the passage-
`way so that the sleeve and the stent enveloped therein
`
`8
`are compressed by the passageway tapering from the
`first diameter to the second diameter, wherein a cross-
`section of said second diameter shows a plurality of
`rounded lobes, wherein spacing of the lobes is selected
`to induce folding during compression of the stent.
`15. A method for loading a stent onto or into a catheter
`comprising.
`providing a loading device comprising a passageway,
`wherein said passageway tapers from a larger first
`diameter to a smaller second diameter;
`making a sleeved stent by placing a flexible sleeve with a
`closed end over said stent;
`placing said sleeved stent into said loading device in said
`tapered portion of said passageway so that an end of the
`sleeve can be grasped from a smaller diameter end of
`the passageway;
`placing said catheter at or into the smaller diameter end of
`the passageway; and
`pulling said sleeve through the smaller diameter end of
`the passageway so that said stent is reduced in diameter
`and moved onto or into said catheter.
`
`10
`
`15
`
`20
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`Page 9 of 9
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