United States Patent [19J
`Marin et al.
`
`111111111111111111111111111111111111111111111111111111111111111111111111111
`US005397355A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,397,355
`Mar. 14, 1995
`
`[54]
`[75]
`
`INTRALUMINAL STENT
`Inventors: Michael L. Marin; Ralph Marin, both
`of New York, N.Y.
`[73] Assignee: Stentco, Inc., Elmwood Park, N.J.
`[21] Appl. No.: 278,546
`[22] Filed:
`Jul. 19, 1994
`Int. Cl.6 ................................................ A61F 2/04
`[51]
`[52] U.S. Cl ....................................................... 623/12
`[58] Field of Search ............................... 623/1, 11, 12;
`606/191-200, 151-158; 411/74, 71, 61;
`138/108, 112
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,910,156 10/1975 Soltysik ................................. 411/61
`4,657,456 4/1987 Anguetin ............................... 411/61
`5,018,919 5/1991 Stephan ................................. 411/61
`5,330,500 7/1994 Song .................................... 606/198
`Primary Examiner-David Isabella
`
`Assistant Examiner-Debra S. Brittingham
`Attorney, Agent, or Firm-Darby & Darby
`
`ABSTRACT
`[57]
`An improved stent provides mechanical anchoring of
`the stent to a blood or other body vessel. The stent has,
`in a preferred embodiment, barbs which remain within
`the surface of the stent when the stent is in its unex(cid:173)
`panded condition, but which extend from the surface of
`the stent when the stent is expanded. These barbs are
`adapted to engage, for example, a graft and/or the inner
`layers of a blood vessel to mechanically attach the stent
`to the vessel. Because friction is not solely relied upon
`to hold the stent in place, the stent may exert less force
`on the blood vessel which, in turn, means that a thinner
`stent requiring less force for expansion may be used. In
`addition, there may be less radial force permanently
`exerted in an artery after stent deployment which may
`be less injurious to the vessel.
`
`6 Claims, 1 Drawing Sheet
`
`Medtronic and Medtronic Vascular
`Exhibit 1007 - Page 1
`
`

`

`U.S. Patent
`
`Mar. 14, 1995
`
`5,397,355
`
`FIG. 2
`
`FIG. I
`
`18
`
`~-12
`
`18
`
`12 ---t+i1rl
`
`FIG. 3
`
`FIG. 4
`
`16
`
`FIG. 5
`
`18
`
`18
`
`16
`
`oc
`
`Medtronic and Medtronic Vascular
`Exhibit 1007 - Page 2
`
`

`

`1
`
`INTRALUMINAL STENT
`
`5,397,355
`
`FIELD OF THE INVENTION
`This invention relates to intraluminal stents and, more 5
`particularly, to intraluminal stents of the type used to
`retain a grafted stent within a blood vessel.
`
`15
`
`2
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a perspective view of a preferred embodi(cid:173)
`ment of the invention showing the stent in its unex(cid:173)
`panded condition;
`FIG. 2 is a perspective view of the stent of FIG. 1 in
`its expanded condition;
`FIG. 3 is an exploded view of a portion of the stent
`showing the manner in which the barb is connected to
`the mesh-like wall of this stent;
`FIG. 4 is a sectional view along the line 4-4 of FIG.
`2;and
`FIG. 5 is a perspective view of a modification of the
`preferred embodiment showing the stent in its unex(cid:173)
`panded condition with a staggered arrangement of cir(cid:173)
`cumferential ribs.
`
`BACKGROUND OF THE INVENTION
`Endoluminal grafts have been used to repair blood 10
`vessels affected with any of a variety of lesions which
`can compromise circulation through the blood vessel to
`a portion of the body. The graft may be made of dacron,
`expanded polytetrafluoroethelyne (ePTFE), or a natu-
`ral substitute such as a vein or artery taken from another
`portion of the body. Typically, the graft is held in place
`within a blood vessel by means of an expandable stent.
`DETAILED DESCRIPTION OF THE
`A variety of different stents have been used and pro(cid:173)
`INVENTION
`posed for this purpose. One stent, known as a Palmaz 20
`In its preferred embodiment, the invention is intended
`stent, has been used as a means for anchoring a graft
`to be used as part of a stented graft, but it is contem-
`within a blood vessel. The Palmaz stent is illustrated in
`plated that the invention would have utility for other
`FIGS.1A and 1B ofPalmaz U.S. Pat. No. 5,102,417. In
`purposes, including but not limited to the purposes
`this patent, the Palmaz stent is characterized as an "ex-
`pandable intraluminal graft" The patent contains an 25 itemized in the Palmaz patent.
`Delivery and deployment of a stent in accordance
`extensive description of the prior art and the problems
`with the invention may be by conventional means in-
`which the Palmaz stent was designed to overcome. U.S.
`Pat. No. 5,102,417 (the "Palmaz patent") and its parents
`eluding, but not limited to, the balloon catheters dis-
`are hereby incorporated by reference into this specifica-
`closed in the Palmaz patents. The mechanical delivery
`tion.
`30 and deployment means disclosed in U.S. patent applica-
`The basic Palmaz stent comprises a mesh-like tubular
`tion Ser. No. 08/196,278 filed on Feb. 10, 1994, in the
`names of Michael and Ralph Marin and entitled APPA-
`member which can be expanded from a first diameter to
`a second diameter. The stent may be expanded by
`RA TUS AND METHOD FOR DEPLOYMENT OF
`means of a balloon catheter, the force applied by the
`RADIALLY EXPAND ABLE STENTS BY A ME-
`balloon exceeding the elastic limit of the stent so that 35 CHANICAL LINKAGE may also be used. Since the
`when the balloon is deflated, the stent remains in its
`device for delivering and deploying the stent forms no
`expanded form. Since expansion of the stent can be
`part of this invention, it is neither illustrated nor de-
`closely controlled, if the stent is expanded into contact
`scribed in this application.
`with the surface of a blood vessel, a graft positioned
`Referring now to the drawings, a stent comprises a
`between the stent and blood vessel can be secured 40 tubular mesh-like member 10. The stent may be made
`within the blood vessel.
`from a stainless steel tube or other metal in which elon-
`As explained in the Palmaz patent, the Palmaz stent
`gated openings 12 are cut, for example by conventional
`provides benefits in addition to the ability to anchor a
`laser cutting techniques or electrical discharge machin-
`graft at a desired location within a blood vessel. For
`ing. Removal of the tubular material to form the elon-
`example, the stent can be used by itself to prevent the 45 gated openings 12 results in a multiplicity of intersect-
`ing members which may be characterized as circumfer-
`recurrence of stenoses, and to prevent recoil of an elas-
`tic vascular stenosis. It is usable in critical vessels such
`entia! ribs 14 and bars 16 which are colinear with the
`as the left main coronary artery where the possibility of
`axis of the tube. As shown in FIG. 1, each of the cir-
`the intimal flap blocking blood flow limits the use of
`cumferential ribs 14 intersects one of the colinear bars
`so 16 at the halfway point of an adjacent rectangular open-
`balloon dilatation procedures.
`ing 12.
`As explained in the Palmaz patents, the stent may be
`made of various materials, but a thin-walled stainless
`steel tube is preferred. The material must deform when
`pressure is applied to the interior surface of the tubular
`member (for example by means of a balloon) and, of
`course, must be strong enough to withstand any pres(cid:173)
`sure applied by the blood vessel (or other body lumen)
`in which it is to be placed.
`The diameter of the unexpanded stent is shown at "d"
`in FIG. 1. When pressure is applied to the interior sur(cid:173)
`face of the stent, the colinear bars 16 are deformed
`causing the openings 12 to assume a diamond-like shape.
`By virtue of this deformation of the bars 16, the diame-
`65 ter of the stent increases from "d" to "D", with the
`length of the stent being reduced proportionately to
`accommodate the increase in diameter (compare FIG. 1
`with FIG. 2).
`
`SUMMARY OF THE INVENTION
`The present invention provides an improvement over
`the basic Palmaz stent in that it provides a means for
`mechanically anchoring the stent to the blood vessel. In 55
`the preferred embodiment, these means comprise barbs
`which remain within the surface of the stent when the
`stent is in its unexpanded condition, but which extend
`from the surface of the stent when the stent is expanded.
`These barbs are adapted to engage the graft and the
`surface of the blood vessel to mechanically attach the
`stent to the vessel. Because friction is not solely relied
`upon to hold the stent in place, the stent may exert less
`force on the blood vessel which, in turn, means that a
`thinner stent requiring less force for expansion may be
`used. In addition, there may be less radial force perma(cid:173)
`nently exerted in an artery after stent deployment
`which may be less injurious to the vessel.
`
`60
`
`Medtronic and Medtronic Vascular
`Exhibit 1007 - Page 3
`
`

`

`5,397,355
`
`3
`In accordance with the invention, a barb 18 extends
`into each of the elongated openings 12 from a circum(cid:173)
`ferential rib 14 at one end of the opening. Each of the
`barbs lies flat in the surface of the tubular member in its
`unexpanded state. It has been discovered that if a pair of 5
`oblique slots 20 and 22 (see FIG. 3) are provided in the
`circumferential rib 14 at its juncture with the barb 18,
`when a force is applied to the inner surface of the stent,
`expansion of the stent will cause the barb 18 to move
`radially outwardly from the surface of the stent as it 10
`expands (see FIG. 4). In other words, as the stent is
`deployed, the barbs 18 are also deployed so that when
`the stent contacts the surface of the blood vessel, the
`barbs penetrate the inner lining of the blood vessel to
`anchor the stent in place.
`The dimensions of the components of the stent, in(cid:173)
`cluding the barb are not critical and may be determined
`empirically. It is believed that the angle a illustrated in
`FIG. 3 should be between 30• and 600, optimally 45•.
`Likewise the length of the slots 20 and 22 may be deter- 20
`mined empirically with a view toward optimizing the
`deployment of the barbs without weakening excessively
`the circumferential ribs 14. The slots 20 and 22 serve an
`important function in causing the barbs to deploy dur-
`ing expansion of the stent.
`It is also possible that opposing barbs 18 may extend
`toward each other in each slot 12. In other words, two
`barbs 18 would extend in opposite directions from each
`circumferential rib 14. This, of course would double the
`number of barbs, which would enhance attachment of 30
`the stent to the blood vessel.
`Also contemplated is a stent having a staggered ar(cid:173)
`rangement of circumferential ribs 14 as shown in FIG.
`5. By staggering or displacing the circumferential ribs
`14 as shown in FIG. 5, expansion of the stent will create
`forces in an oblique direction which may increase the
`
`25
`
`4
`strain in the ribs 14 and thereby magnify the force on
`the junction between each barb 18 and rib 14.
`Many modifications of the illustrated embodiment are
`possible within the scope of the invention. The illus(cid:173)
`trated embodiment is therefore to be considered in all
`respects as illustrative and not restrictive; the scope of
`the invention being indicated by the appended claims,
`and not limited to the foregoing description.
`What is claimed is:
`1. An implantable intraluminal stent, comprising a
`tubular wall defined by a multiplicity of intersecting
`members forming a multiplicity of openings, said tubu(cid:173)
`lar wall being expandable from a first diameter to a
`second diameter upon application of a radially directed
`15 force to the interior surface of said wall, at least some of
`said intersecting members including a barb, each said
`barb lying flat in the surface of said tubular wall when
`it is unexpanded and extending out of the surface of said
`tubular wall for engagement of a lumen when it is ex(cid:173)
`panded.
`2. A stent according to claim 1, wherein said barbs
`are colinear with the axis of said tubular wall.
`3. A stent according to claim 2, wherein said inter(cid:173)
`secting members include circumferential ribs, said barbs
`extending from said ribs.
`4. A stent according to claim 1, wherein oblique slots
`are formed in said ribs at each intersection of a barb and
`rib.
`5. A stent according to claim 2, wherein oblique slots
`are formed in said ribs at each intersection of a barb and
`rib.
`6. A stent according to claim 3, wherein oblique slots
`are formed in said ribs at each intersection of a barb and
`35 rib.
`
`* * * * *
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Medtronic and Medtronic Vascular
`Exhibit 1007 - Page 4
`
`