United States Patent [19]
`Williams et a1.
`
`US005437083A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,437,083
`Aug. 1, 1995
`
`[54]
`[75]
`
`[73]
`
`[21]
`[22]
`[51]
`[52]
`[58]
`
`[56]
`
`STENT-LOADING MECHANISM
`
`Inventors: Michael S. Williams, Chapel Hill,
`NC; Lilip Lau, Sunnyvale, Ca1if.;
`Farhad Khosravi, Belmont, Calif.;
`William Hartigan, Fremont, Cali?;
`Avegel Hernando, Union City, Calif.
`
`.
`Ass1gnee: Advanced Cardiovascular Systems,
`Inc” Santa Clara, Calif
`
`Appl. No.: 66,707
`_
`F?ed:
`
`May 24’ 1993
`
`6
`
`el'd of'
`
`_
`""""""""""" " 1323p 19/ ozég‘j‘gg
`"""""""""
`234 zéz 283_
`""""""
`/164_ 606/131 2’01 1’
`’
`’
`’
`
`References Cited
`
`Us PATENT DOCUMENTS
`
`696,289 3/1902 Williams ............................. .. 29/235
`5,189,786 3/1993 Ishikawa et a1. .................... .. 29/285
`
`FOREIGN PATENT DOCUMENTS
`
`159065 2/1921 United Kingdom .............. .. 269/164
`Primary Examiner-Tamara L. Graysay
`Attorney, Agent, or Firm—-—Fulwider Patton Lee &
`Utecht
`
`ABSTRACT
`57
`.
`_
`_
`[
`1
`A stent-loadmg mechanism for loading a stent onto a
`balloon delivery catheter of the kind typically used in
`typical percutaneous transluminal coronary angioplasty
`(PT CA) procedures.
`The device comprises a series of plates having substan
`tially ?at and parallel surfaces that move in a rectilinear
`fashion with respect to each another. A stent carrying
`catheter can be disposed between these surfaces to af?x
`the stent onto the outside of the catheter by relative
`motion between the plates. The plates have multiple
`degrees of freedom and may have force-indicating
`transducers to measure and indicate the force applied to
`the catheter during af?xation of the stent.
`
`13 Claims, 3 Drawing Sheets
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`Page 1 of 7
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`

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`U.S. Patent
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`Aug. 1, 1995
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`Sheet 1 of 3
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`Reissue/256v
`Fw/p ae
`GAS
`$00246‘
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`Page 2 of 7
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`Aug. 1, 1995
`Aug. 1, 1995
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`Sheet 2 of 3
`Sheet 2 of 3
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`5,437,083
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`US. Patent
`US. Patent
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`5,437,083
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`0/871 19 Y
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`3/9:
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`Page 3 of 7
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`Aug. 1, 1995
`599lL,meA
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`Sheet 3 of 3
`Sheet 3 of 3
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`5,437,083
`5,437,083
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`US. Patent
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`US. Patent
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`Page 4 of 7
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`

`1
`
`STENT-LOADING MECHANISM
`
`BACKGROUND OF THE INVENTION
`Field of the Invention
`This invention relates to a stent loading device that
`will automatically load a stent onto the distal end of a
`balloon dilatation catheter assembly, for example, of the
`kind used in typical percutaneous transluminal coronary
`angioplasty (PT CA) procedures.
`In typical PTCA procedures, a guiding catheter is
`percutaneously introduced into the cardiovascular sys
`tem of a patient through the brachial or femoral arteries
`and advanced through the vasculature until the distal of
`the guiding catheter end is in the ostium. A guidewire
`and a dilatation catheter having a balloon on the distal
`end are introduced through the guiding catheter with
`the guidewire sliding within the dilatation catheter. The
`guidewire is ?rst advanced out of the guiding catheter
`into the patient’s coronary vasculature and the dilata
`tion catheter is advanced over the previously advanced
`guidewire until the dilatation balloon is properly posi
`tioned across the lesion. Once in position across the
`lesion, a ?exible, expandable, preformed balloon is in
`?ated 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 de?ated to a small pro?le, so
`that the dilatation catheter can be withdrawn from the
`patient’s vasculature and blood ?ow resumed through
`the dilated artery. As should be appreciated by those
`skilled in the art, while the procedure just described is
`typical, it is not the only method used in angioplasty.
`In angioplasty procedures of the kind referenced
`above, there may be restenosis of the artery, which may
`require another angioplasty procedure, a surgical by
`pass operation, or some method of repairing or
`strengthening the area. To reduce the chance of reste
`nosis and strengthen the area, a physician can implant
`an intravascular prosthesis for maintaining vascular
`patency, typically called a stent, inside the artery at the
`lesion. The stent is typically expanded to a larger diame
`ter, often by the balloon portion of the catheter. The
`45
`stent may be of the self-expanding type.
`
`5,437,083
`2
`entirely adequate in achieving a satisfactory crimp.
`Further, some self-expanding stents are dif?cult to load
`by hand onto a delivery device such as a catheter.
`In one embodiment of the present invention, the
`stent-loading device includes a tubular member housing
`a bladder. The tubular member and bladder are de
`signed to hold a stent that is to be loaded onto a balloon
`catheter assembly. Upon placement of the stent over the
`balloon portion of the catheter, a valve in the loading
`device is activated to in?ate the bladder. The bladder
`compresses the stent radially inwardly to a reduced
`diameter onto the balloon portion of the catheter, to
`achieve a snug ?t. In this way the stent can be affixed
`onto the distal end of a balloon catheter with a mini
`mum of human handling.
`In other embodiments of the present invention, the
`stent-loading device is made of sliding plates having ?at
`surfaces that allow a stent carrying catheter to be re
`ceived in between them. The surfaces are moved rela
`tive to one another to apply force uniformly to the
`outside of the stent disposed on the catheter, allowing
`the stent to be crimped onto the outside of the catheter.
`These and other advantages of the invention will
`become more apparent from the following detailed
`description thereof when taken in conjunction with the
`accompanying drawings.
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a cross-sectional schematic of one embodi
`ment of the stent-loading device depicting the bladder
`and chamber for receiving the stent.
`FIG. 2 is a cut-awayperspective view of the stent
`loading device of FIG. 1.
`FIG. 3 is a cut-away perspective view of the stent
`loading device of FIG. 1, showing a balloon catheter
`assembly about to be inserted into the device, and a
`stent received by the device.
`FIG. 4 is a cut-away perspective view of the stent
`loading device of FIG. 1, when it is operated to load a
`stent onto a balloon catheter assembly that has been
`placed inside the device.
`FIG. 5 is a perspective view of a second embodiment
`of the present invention depicting sliding plates with a
`stent mounted to be placed between the plates.
`FIG. 6 is a perspective view of the back of one of the
`blocks of the embodiment shown in FIG. 5.
`FIG. 7 is a side view of the second embodiment of the
`present invention.
`FIG. 8 is a perspective view of a third embodiment of
`the present invention.
`FIG. 9 shows the slider plate of the embodiment of
`FIG. 8.
`FIG. 10 shows the spring-loaded plate of the embodi
`ment of FIG. 8.
`FIG. 11 shows the housing of the embodiment of
`FIG. 8.
`~
`
`SUMMARY OF THE INVENTION
`This invention is directed to a vascular prosthesis
`loading device, which automatically loads a stent onto
`the distal end of a catheter assembly, with a minimum of
`human handling, to better secure the stent onto the
`catheter while the stent is being delivered through the
`patient’s vasculature.
`The present invention attempts to solve several prob
`lems associated with placing stents onto balloon cathe
`ters. In procedures where the stent is placed over the
`balloon portion of the catheter, one must crimp the stent
`onto the balloon portion, to prevent the stent from
`sliding off the catheter when the catheter is advanced in
`a patient’s vasculature. In the past this crimping was
`often done by hand, which was found to be unsatisfac
`tory clue to uneven force being applied, resulting in
`non-uniform crimps. In addition, it is difficult to judge
`when a uniform and reliable crimp has been applied.
`Furthermore, the more the stent is handled, the greater
`the chance of human error in crimping the stent prop
`erly. Though some tools, such as ordinary pliers, have
`been used to apply the stent, these tools have not been
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`As shown by FIGS. 1-4, the ?rst embodiment of the
`stent-loading device 1 includes an elongated tubular
`member 5, having an open end 10 and a sealed-off end
`15. The tubular member houses an elastic bladder 20,
`which extends longitudinally along the inside of the
`tubular member. The bladder is secured to the tubular
`member by fastener ring 25, which clamps the bladder
`onto the tubular member. The bladder extends out of
`
`65
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`5,437,083
`3
`4
`the open end of the tubular member and is folded over
`assembly. The delivery catheter, now loaded with a
`outside end 30 of the tubular member.
`stent, is ready to be inserted into the body of a patient
`for deployment.
`The tubular member can be made of a stainless steel
`or polytetra?uoroethylene (manufactured under the
`Furthermore, the stent-loading device of FIGS. 14
`trademark TEFLON) lined hypotube. The bladder can
`may be used to compress and af?x a stent that has been
`be made of any ?exible, elastic material, such as poly
`?rst manually placed over a balloon catheter.
`ethylene material.
`Turning attention now to the embodiment of FIGS.
`The bladder is sealed at its end 35. The bladder end
`5-7, there is shown a second embodiment of the present
`may be sealed by heat sealing, by an adhesive, by tying,
`invention. In FIG. 5 there is shown an isometric per
`or by clamping with a hemostat, depending on the blad
`spective view of the device. The device comprising a
`der material used. As shown in the ?gures, the bladder
`pair of plates, a lower support plate 100 and an upper
`seals from atmosphere an annular ?uid chamber 40 in
`support plate 120, that form ?at surfaces or faces 125,
`the tubular member. Chamber 40 can be placed under
`130, in between which a stent-carrying catheter may be
`pressure by a pressurized ?uid source 50, which is in
`placed, as indicated by arrow 135. Uniform pressure
`?uid communication with the chamber via in?ation
`may be applied to crimp the stent onto the catheter, by
`port 55 ?tted with an in?ation valve 60. In the preferred
`reciprocating surfaces 125, 130 relative to one another.
`embodiment an adaptor with a male-threaded Luer
`Plates 100, 120 may be made of aluminum, and may be
`?tting is used as an in?ation port. A syringe, an in?a
`hollow. Thin rubber or elastomeric surfaces are lami
`tion/de?ation device commonly referred to as an “inde
`nated onto faces 125, 130 to better grip the stent and
`?ator,” a compressed ?uid source or another pressuriz
`catheter and prevent them from sliding. The upper face
`ing means 50 is attached to the in?ation port.
`130 has a thicker rubber or elastomeric surface, about 3"
`Operation of the stent-loading device of FIGS. 1-4
`thick, and the lower face 125 has a thinner rubber sur
`will now be described. When it is desired to load a stent
`face, about i" thick.
`65 onto a balloon catheter assembly 70, a stent is in
`Lower support plate 100 is ?xed to base 140 while
`serted inside the open end 10 of the tubular member 5.
`upper support plate 120 is movable, being af?xed to ?at
`The stent is con?ned inside the tubular member by the
`rectangular surface 145 which in turn is af?xed to chan
`inner walls of the bladder, with the bladder being in a
`nel-shaped block 150. Channel-shaped block 150 trans
`non-compressed state. The collapsed balloon portion
`lates in two directions. Channel-shaped block 150 has a
`85, adjacent distal end 90 of the balloon catheter 95, is
`horizontally-extending channel or groove 155 extend
`inserted inside the stent so the stent overlies the balloon
`ing along its length through which it slidably receives a
`portion. At this point there is no pressure inside the
`guide-bearing surface 160. Guide-bearing surface 160 in
`sealed ?uid chamber 40.
`turn has a vertically-extending channel or groove 165
`To load and attach the stent onto the balloon portion
`on its back side, as can be seen in FIG. 6, which receives
`of the catheter assembly, the catheter is brought into
`a rail 170. Rail 170 is ?xed to upright channel-shaped
`operating engagement with the stent loading device.
`support 175. Upright channel support 175 in turn has a
`The catheter has been checked and prepped before this
`groove 180 that can slidably receive a ?xed rail 185.
`time, and the pro?le of the balloon portion 85 has been
`Fixed rail 185 is immobile, ?xed to a vertical post 190,
`reduced to its
`As illustrated in FIG. 3, the
`which is attached to base 140.
`catheter is inserted with its distal end ?rst into open end
`Spring arms 172, 174 provide bias along the axial
`10 of the tubular member. To achieve insertion, the
`direction (the direction of arrow 135) to keep block 150,
`balloon catheter assembly may be held stationary while
`guide-bearing surface 160, and rail 170 together. In
`the stent delivery device is moved relative to the cathe
`addition spring arms 172, 174 provide a vertical bias to
`ter. The catheter distal end is inserted far enough into
`keep faces 125, 130 separated.
`the tubular member so the stent is positioned over the
`As can be appreciated from an examination of FIGS.
`desired position on the catheter. At this point the stent
`5—7, guide bearing surface 160 allows two degrees of
`is not ?xed onto the balloon catheter assembly, because
`freedom for the translation of plate 120, that is, allowing
`the stent has not been compressed.
`for movement along vertical and horizontal directions.
`The stent is attached onto the balloon 85 of catheter
`Preferably these directions are substantially orthogonal
`95 by ?rst pressurizing chamber 40. As chamber 40 is
`pressurized, tubular member 5 becomes pressurized,
`directions, that is, at right angles to one another, as
`shown by the unmarked double headed arrows in FIG.
`and the pressure is transferred to the bladder, which
`5.
`causes it to compress radially inwardly the stent onto
`Furthermore, the use of several redundant sliding
`the balloon portion of the catheter, at a substantially
`surfaces, such as guide-bearing surface 160 in conjunc
`uniform rate. The in?ation of the chamber is depicted
`tion with channel-shaped support 175, both sliding
`by dotted shading in FIG. 4. Pressurized ?uid may be
`introduced into chamber 40 through in?ation port 55
`along rails in the vertical direction, allows for reduced
`friction in the event there is excessive friction along one
`controlled by a suitable valve 60 by way of a com
`sliding surface. Multiple sliding surfaces may be em
`pressed ?uid source 50, as shown in FIG. 1. The ?uid
`ployed for horizontal travel as well.
`may also be introduced by way of a syringe or plunger
`Furthermore, upper block 150 is spring biased up
`arrangement, such as an inde?ator. Other suitable pres
`wards from lower support plate 100 by spring arms 172,
`surizing gas or ?uid sources are contemplated, as should
`be appreciated by one skilled in the art.
`174. The arms provide for the upper block 150 to be
`spaced from lower support plate 100, and to give a
`After a predetermined pressure has been achieved
`and the stent has been affixed to the outside of the bal
`resilient feel to an operator pressing down on upper
`loon portion of the balloon catheter assembly, the blad
`block 150. The spring-biased arms may have spring
`der 10 is decompressed by releasing the pressurized
`tensioning means to adjust the spring tension in the
`?uid from inside the chamber through valve 60. Tubu
`arms, as well as dampening means for providing damp
`ening.
`lar member 5 is then withdrawn from over the catheter
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`5,437,083
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`nary angioplasty, it will be appreciated by those skilled
`In addition, a force transducer 195, such as a strain
`gage or piezoelectric crystal, may be disposed in plate
`in the art that modi?cations may be made to the present
`100 and/or plate 120, or in faces 125, 130, to measure
`invention to allow the present invention to be used to
`the contact force applied to the stent disposed between
`load any type of prosthesis. The present invention is not
`the plates. Force transducer 195 may have a display 200,
`limited to stents that are deployed in a patient’s vascula
`giving visual and/or audio output, to provide feedback
`ture, but has wide applications to loading any type of
`to the operator and to indicate when either suf?cient
`graft, prosthesis, liner or similar structure. Further
`and/or excessive force has been imparted to the cathe
`more, the stent may be delivered not only into coronary
`ter.
`arteries but into any body lumen. Other modi?cations
`Operation of the FIGS. 5-7 embodiment is achieved
`can be made to the present invention by those skilled in
`by placing a catheter that has a stent disposed about its
`the art without departing from the scope thereof.
`stent-receiving portion, which in a balloon catheter
`What is claimed is:
`would be the balloon portion of the catheter, in between
`1. A stent-loading device for loading a stent onto a
`the space formed between the substantially ?at surfaces
`catheter comprising:
`of faces 125, 130. The operator then gently reciprocates
`a ?rst substantially flat surface and a second substan
`plate 120 to move face 130, which contacts the stent
`tially ?at surface, said second ?at surface being
`receiving catheter, with respect to face 125, which is
`disposed substantially in parallel to said ?rst ?at
`?xed and also contacts the catheter, to apply a slight
`surface and spaced therefrom a distance sufficient
`downward force and evenly crimp the stent onto the
`to allow a catheter having a stent disposed about its
`catheter. The gentle reciprocating motion of the two
`periphery to be received between said ?rst and
`substantially flat rubberized faces 125, 130, together
`second surfaces; and
`with the downward application of force, insures an
`means for allowing said surfaces to be forced toward
`even application of force to the outside of the stent and
`one another while simultaneously allowing said
`achieves a uniform crimping of the stent onto the cathe
`surfaces to be shifted laterally relative one another
`ter.
`for crimping the stent, disposed about the catheter
`25
`Turning attention now to FIGS. 8-11, there is shown
`and positioned between said ?rst and second sur
`another embodiment of the present invention employ
`faces, onto the outside of the catheter.
`ing sliding plates that operate in principle according to
`2. The stent-loading device of claim 1, wherein said
`the embodiment of FIG. 5. A horizontally-sliding plate
`?rst and second substantially ?at surfaces are formed
`215 moves relative to a vertically-sliding plate 220.
`from plates.
`Horizontally-sliding plate 215 slides along grooves 225
`3. The stent-loading device of claim 2, wherein said
`in housing 230, via rails 235. Vertically-sliding plate 220
`?at surfaces are elastomeric.
`is retained in U-shaped housing 230 by a ridge 240, but
`4. The stent-loading device of claim 2, wherein said
`is free to travel upwards along the inside edge 245 of
`?at surfaces are spring biased towards one another.
`housing 230. Vertically-sliding plate 220 has a push
`5. The stent-loading device of claim 2, wherein said
`plate 250 connected to it by springs 255. By pushing on
`?rst ?at surface comprises a stationary plate, and said
`push plate 250 the plates 215 and 220 can be resiliently
`second ?at surface comprises a moveable plate, wherein
`biased together. In this way a user may apply pressure
`said moveable plate is rigidly attached to a block ele
`to the underside of vertically-sliding plate 220 by push
`ment that is shiftably mounted to a support member that
`ing on push plate 250. As can be appreciated from
`is in turn rigidly attached to said stationary plate.
`FIGS. 8-11, horizontally sliding plate 215 and vertical
`6. The stent-loading device of claim 5 wherein said
`ly-sliding plate 220 move along substantially orthogonal
`block has a groove formed therein and further compris
`directions.
`ing a guide-bearing member slideably received within
`In the operation of the device, a stent carrying cathe
`said groove wherein said guide-bearing member has a
`ter 260 is placed in between plates 220 and 215, with
`groove formed therein which is perpendicularly ori
`catheter 260 entering through slot 265, and facing trans
`ented relative said groove formed in said block.
`verse to the direction of movement of horizontally-slid
`7. The stent-loading device of claim 6, wherein said
`ing plate 215. Thereinafter, horizontally-sliding plate
`support member has a rail attached thereto, and
`215 is moved relative to vertically-sliding plate 220, to
`wherein said rail is slideably received within said
`compress the stent about the catheter. As can be seen
`groove formed in said guide-bearing member.
`from the drawings, horizontally-sliding plate 215 is
`8. The stent loading device of claim 2, wherein said
`constrained by grooves 225 to move along a single
`?rst and second surfaces are plates, and further compris
`direction relative to vertically sliding plate 220.
`ing a housing supporting said plates.
`As before, a force measuring transducer and suitable
`9. The stent loading device of claim 8, wherein said
`output may be placed in either or both of plates 215 and
`220 to measure the force imparted to the stent-carrying
`housing is sized to ?t in a human hand. i
`10. The stent loading device of claim 8, wherein said
`catheter and indicate the results.
`plates are constrained by said housing to move in sub
`The embodiment of FIGS. 8-11 is sized to ?t into a
`stantially orthogonal directions.
`user’s palm. The horizontally-sliding plate 215 can be
`reciprocated with a thumb while housing 230 is held in
`11. The stent loading device of claim 8, further com
`the user’s palm, and the user’s ?ngers can apply pressure
`prising a plurality of springs attached to one of said
`plates, and a push plate attached to said springs.
`to push plate 250 af?xed to the underside of vertically
`sliding plate 220. Springs 255 oppose the force of the
`12. The stent-loading device of claim 1, further com
`user’s fngers. In this way feedback can be experienced
`prising a force transducer to measure the force applied
`by the user.
`to at least one of said ?at surfaces.
`While in the preferred embodiment the stent de
`13. The stent-loading device of claim 12, further com
`prising means for indicating the force measured by said
`scribed is intended to be an intraluminal vascular pros
`thesis for use within a blood vessel, and the balloon
`transducer as said stent is crimped onto said catheter.
`delivery catheter is of the kind'used in therapeutic coro
`# i * * *
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