(19)
(11)EP 1 941 848 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
28.07.2010 Bulletin 2010/30

(21)Application number: 08250014.1

(22)Date of filing:  03.01.2008
(51)International Patent Classification (IPC): 
A61F 2/90(2006.01)

(54)

Intraluminal medical device having varialble axial flexibility about the circumference of the device

Intraluminale medizinische Vorrichtung mit variabler Axialbeweglichkeit um den Umfang des Geräts

Dispositif médical intralumineux ayant une flexibilité axiale variable autour de la circonférence du dispositif


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

(30)Priority: 08.01.2007 US 620749

(43)Date of publication of application:
09.07.2008 Bulletin 2008/28

(73)Proprietor: Cordis Corporation
Miami Lakes, FL 33014 (US)

(72)Inventors:
  • Marrey, Ramesh V
    NJ 07920 (US)
  • Krever, Matthew
    Warren, NJ 07059 (US)
  • Olsen, Daniel
    Califon, NJ 07830 (US)
  • Burgermeister, Robert
    Bridgewater, NJ 08807 (US)

(74)Representative: Belcher, Simon James 
Urquhart-Dykes & Lord LLP Tower North Central
Merrion Way Leeds LS2 8PA
Merrion Way Leeds LS2 8PA (GB)


(56)References cited: : 
WO-A-98/34668
WO-A-2008/005111
US-A1- 2001 041 930
WO-A-2007/082189
US-A- 5 855 600
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] This invention concerns an expandable intraluminal medical device for use within a body passageway or duct in which the device has regions that exhibit differing degrees of flexibility about the device.

    [0002] The use of intraluminal prosthetic devices has been demonstrated to present an alternative to conventional vascular surgery. Intraluminal prosthetic devices are commonly used in the repair of aneurysms, as liners for vessels, or to provide mechanical support and prevent the collapse of stenosed or occluded vessels.

    [0003] Intraluminal endovascular prosthetics involve the percutaneous insertion of a generally tubular prosthetic device, such as a stent, into a vessel or other tubular structure within the vascular system. The stent is typically delivered to a specific location inside the vascular system in a low profile (pre-deployed) state by a catheter. Once delivered to the desired location, the stent is deployed by expanding the stent into the vessel wall. The expanded stent typically has a diameter that is several times larger than the diameter of the stent in its compressed state. The expansion of the stent may be performed by several methods known in the art, such as by a mechanical expansion device (balloon catheter expansion stent) or by self-expansion.

    [0004] Preferably, a stent would possess a minimum width and wall thickness, which should minimize thrombosis at the stent site after implantation. The preferred stent would also possess sufficient hoop strength to resist elastic recoil of the vessel. Many current tubular stents employ a multiplicity of circumferential sets of strut members connected by either straight longitudinal connectors or undulating longitudinal connecting connectors in an effort to fulfill the above requirements.

    [0005] The strut members, of which there are ordinarily a plurality that extend around the circumference of the device, can be formed from a number of diagonal sections in turn connected to curved or arced members reminiscent of elbows, thereby forming a zig-zagging structure in a closed ring arrangement. When expanded, the stent provides structural support for the vessel wall. Strut members may be formed from a single piece of metal having a uniform wall thickness and generally uniform strut width. The curved members are formed having a generally uniform wall thickness and generally uniform width.

    [0006] While the geometry of the stent members is uniform, under load, the strain experienced by each strut member is not. The "stress" applied to the stent across any particular cross section is the force per unit area. These dimensions are those of pressure, and are equivalent to energy per unit area. The stress applied to the stent includes forces experienced by the stent during deployment, and comprises the reactive force per unit area applied against the stent by the vessel wall. The resulting "strain" (deformation) that the stent experiences is defined as the fractional extension perpendicular to the cross section under consideration.

    [0007] During deployment and in operation, each strut member experiences varying load along its length. High stress and/or strain can cause cracking of the metal and potential fatigue failure of the stent under the stress of a beating heart. It should also be remembered that arteries "pulse" at typically 70 times per minute or more, about 40 million times per year - necessitating that these devices are designed to last in excess of 108 loading cycles for a 10-year life. Thus, guarding against cyclic fatigue failure is a particularly important consideration in stent design. Designs can be physically tested and analytically evaluated to ensure acceptable stress and strain levels are achievable based on physiologic loading considerations. This is typically achieved using the traditional stress/strain-life (S-N) approach, where design and life prediction rely on a combination of numerical stress predictions as well as experimentally-determined relationships between the applied stress or strain and the total life of the component. Fatigue loading for the purpose of this description includes, but is not limited to, axial loading, bending, torsional/twisting loading of the stent, individually and/or in combination. One of skill in the art would understand that other fatigue loading conditions can also be considered.

    [0008] A bifurcation is a location where the vessel divides into two branches or parts, that is, a main branch vessel and a side branch vessel. One, two, or both branches may exhibit a curvature or bend. The vessel bifurcations generally have circumferential asymmetry. That is, bifurcated vessels generally exhibit asymmetry around their circumference at the point where the main vessel divides into one or more branches. Thus, the opening in the side branch vessel where the side branch vessel joins the main branch vessel may be asymmetrical. The side branch vessel may join the main branch vessel at an oblique angle, which may contribute to the asymmetry of the side branch opening.

    [0009] In any event, a bifurcation or bend in a vessel can present challenges if an implant is to be deployed there. Where the implant needs to be in a specific orientation (such as for maximizing the therapeutic effect, such as to conform to the bend in one of the main branch or side branch vessels, it would be helpful if the implant were flexible over at least a portion of its surface, so that the device could conform to the bend.

    [0010] US-5855600 discusses a stent of generally cylindrical open-ended shape. The stent has a greater rigidity in a mid section of the length of the cylinder a greater flexibility at each end of the cylinder.

    [0011] WO-A-98/34668 relates to an intraluminal prosthesis which can be provided with varying flexibility or rigidity at different portions along its length. In one embodiment connecting members are omitted to increase flexibility.

    [0012] US-A-2001/0041930 discusses a variable flexibility stent which has variable flexibility and stiffness along its length. In one embodiment annular members have a larger cross-section near the middle of the stent and a smaller cross-section towards the ends of the stent.

    [0013] US-2005/0149168A1 discusses a stent to be deployed on a bend. The stent may include a strip extending across at least a portion of the length of the stent. The strip may have a greater flexibility than the rest of the stent, for example, by providing it with struts of greater flexibility.

    [0014] WO-2007/053791 forms prior art under Article 54(3) EPC. It discusses a stent in which some structural elements are not connected to flex linkages to facilitate unidirectional bending.

    [0015] A medical implant, such as a stent, which has circumferential regions that exhibit a relatively high degree of flexibility when compared to other circumferential regions of the device, to exhibit relatively increased flexibility in at least one bending direction while also providing a relative increased degree of stiffness in another bending direction, would be advantageous and advance the state of the art. Such an arrangement, provided for in the implant, would allow the stent to preferentially bend in at least one direction, so the device may conform to curves in the vessels as it traverses in its crimped state on the way to the deployment site, or otherwise in its deployed state conform to the geometry of the vessel at the deployment site, if the implant is deployed at a bend. Likewise, flexibility and conformability are advantageous where the vessel has lesions that render the interior vessel configuration nonlinear.

    [0016] According to the present invention there is provided an implantable medical device as defined in appended claim 1. The present invention is directed to an expandable intralumenal medical device, such as a medical implant, possessing regions of varying axial flexibility or stiffness along the circumference of the device. In one specific embodiment, the present invention is a stent, having substantially cylindrical shape, and the stent is provided with locations of variable axial flexibility, stiffness, or both, at locations about the circumference. That is, the stent can be provided with structure that renders it axially flexible in at least one region of the device circumference, or, in at least one region of the device circumference, axially stiff, or, it can be provided with structural attributes in a plurality of regions that render it both axially flexible and stiff. In yet another specific aspect, the present invention is directed to an expandable intralumenal medical device, for use within a body passageway or duct. The device possesses at least one circumferential region or segment exhibiting greater axial flexibility than at least a second circumferential region of the device. Alternatively, the device possesses at least one circumferential region or segment exhibiting greater axial stiffness than at least a second circumferential region of the device. Again, the expandable intralumenal medical device can be a medical implant such as a stent.

    [0017] In a particular embodiment of the invention, the stent has at least two regions exhibiting a relatively greater degree of axial flexibility than at least two other regions. By way of alternative, the stent has at least two regions exhibiting a relatively greater degree of axial stiffness than at least two other regions. In a more specific aspect of the invention, the regions are positioned in an alternating relationship around the circumference of the device, so that, for example, a given region of relatively greater axial flexibility is positioned between regions of relatively greater axial stiffness (and vice versa).

    [0018] In a more specific embodiment of the invention, the regions exhibiting a relatively greater degree of axial flexibility are positioned to oppose each other across the cross-section of the device, and the regions exhibiting a relatively greater degree of axial flexibility are positioned to oppose each other across the device. In a more specific arrangement, the regions of increased flexibility are positioned 180° from each other, and the regions of increased stiffness are positioned 180° across from each other.

    [0019] In a specific embodiment of the present invention, the medical device can bend in substantially only one direction, owing to the structural attributes and/or construction that provide the device with axially stiff and axially flexible regions. A structural arrangement of this kind can result by arranging the axially stiff and axially flexible regions such that there is only one preferential bending direction of the device. This particular region or side becomes the interior, or short side, of the bend, and is relatively more flexible than other regions of the device.

    [0020] The device of the present invention, provided with a relatively stiff axial region and a relatively flexible axial region facilitates device orientation, a desirable feature as it travels (1) through curves or bifurcations in the vessel, (2) over curves or bends in the guidewire, or (3) traverses other eccentricities located within the vessel that force the member into a curved path. So long as the device possesses a sufficient degree of freedom to rotate about its longitudinal axis, it will assume the path of least resistance in the course of its travel, and thereby rotate/orient itself to conform to the bend in the vessel. Thus, orientation of the device can be attained as a result of device rotation to align the relatively flexible regions of the device to the bending direction of the vessel or guidewire.

    [0021] Aside from being adapted to pass relatively easily through bends and curves in the vasculature, the device can be used in a number of beneficial ways. A device, such as a stent that is deployed at the site of or in the vicinity of a bifurcation may have circumferentially asymmetrical design features intended to conform to the bifurcation, and in particular, the side branch ostium. Such devices must be deployed in the proper circumferential orientation, a result that can be obtained by providing the vessel with-a relatively stiff region and a relatively flexible region, thereby allowing the device to self orient to the curve in the vessel. The self-orienting nature is useful where the bend, so to speak, is imparted by the guidewire, which passes through the device. For example, the device may travel over a guide wire passed into a bifurcation side branch, allowing a properly oriented device to be deployed in its in the side branch. In yet another example, a guidewire having a prebent section can be used to effect orientation of the device in situations where vessel characteristics are not of an orientation-producing nature. In other words, by positioning the bend in the guidewire at the desired location, the device will orient itself as it traverses the bend. This arrangement is advantageous where it is desirable to achieve orientation in a relatively straight vessel segment. In any event, with these arrangements, rotation of the device for positioning purposes, whether for deployment or other medically useful purpose is facilitated.

    [0022] Upon implantation of the medical implant into a vessel of an animal, such as the artery of a human, the implant can be aligned to conform to the vessel shape and geometry. This manifests itself in at least two ways. First, the implant can flex or bend in accordance with curves or bends in the vessel, when in proper alignment with the vessel bend. For instance, the circumferential region of the implant that exhibits a relatively greater degree of axial flexibility can be aligned to curve along with a bend in the artery, thereby conforming to the path of the vessel. In this arrangement, at least one circumferential region of the implant with relatively greater flexibility is in axial tension and one region is in axial compression. Second, due to the presence of lesions, the vessel may exhibit a non-symmetrical cross section at the target site of implantation. Therefore, aligning the stent so that a flexible region is in contact with the lesions would permit the stent to conform to the region where the lesion is present.

    [0023] The stent of the present invention, possessing circumferential regions of different axial flexibility and stiffness, should be easier to deploy when compared to stents of uniform stiffness/flexibility. The stent can be aligned for delivery through a tortuous arterial pathway in order to provide flexibility in the desired bending plane. The stent would minimize circumferential twisting during the expansion process. Thus, the orientation of the flexible sections or regions of the stent would remain in the same locations after implantation.

    [0024] It should be understood that a stent is usually delivered in a crimped state via a delivery device, and thus may pass through a curve or bend in a vessel while in the crimped state. The stent of the present invention is capable of flexing to conform to the curve or bend whether in the crimped state, or later, at the time of deployment (and subsequent thereto), when the stent is expanded.

    [0025] The device of the present invention can be used in a method of performing a medical procedure on a patient comprising the steps of moving the medical implant of claim 1 to a site of diagnosis or therapy within a conduit in a patient's body, and permitting the medical implant to orient into position within the conduit. The sit may be a bifurcation in a vessel.

    [0026] Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

    Figure 1 is a perspective view of an intraluminal stent in an unexpanded or crimped, pre-deployed condition.

    Figure 2 is a perspective view of an intraluminal stent in the fully expanded condition.

    Figure 3 is a perspective view of an example, useful for understanding the present invention.

    Figure 4 is a perspective view of another example, useful for understanding the present invention.

    Figure 5 is a perspective view of yet another example, useful for understanding the present invention.

    Figure 6 is a perspective view of yet still another example, useful for understanding the present invention.

    Figure 7 is a perspective view of yet still another example, useful for understanding the present invention.

    Figures 8A-8F depict alternative arrangements for constructing devices of the present invention.

    FIG. 9 is a cross sectional view of a first bifurcation configuration in a patient's vasculature; and

    FIG. 10 is a cross sectional view of a second bifurcation configuration in a patient's vasculature.



    [0027] Figure 1 shows an exemplary medical device, here a stent, illustrating a device that can be modified in accordance with the present disclosure. The medical device 100 comprises one or more hoop components 106 having a tubular configuration with proximal and distal open ends defining a longitudinal axis extending therebetween. Each hoop component is formed as a continuous series of substantially longitudinally oriented radial strut members 108 and a plurality of radial arc members 110 connecting adjacent radial struts.

    [0028] The device of the present invention includes connecting elements 114 joined to longitudinally adjacent hoop components 106. In this specific depiction, adjacent flexible struts 116 are connected at opposite ends in a waveform-like pattern shown here as substantially N-shaped. As illustrated, the plurality of flexible arc members 118 of connecting elements 114 have a substantially semi-circular configuration and are substantially symmetric about their centers, though these specific features should not be regarded as essential to the invention.

    [0029] Each connecting element 114 has two ends. One end of connecting elements 114 is attached to the radial arc 110 on one hoop, for example hoop 106(b), and the other end of the connecting element 114 is attached to a second radial arc 110 on an adjacent hoop, for example hoop 106(c). The connecting elements 114 connect longitudinally adjacent hoops 106(a) - (d) together at to radial are connection regions 117. Figure 2 shows the device of Figure 1 in an expanded state. The device may be expanded by an expansion device, such as a balloon, or it may be made of a self-expandable material, such as nitinol.

    [0030] The device can be provided with at least one region of axial flexibility greater than at least other region of the device in a number of ways. For instance, by manipulating the number, location, and design parameters of the connecting elements 114, the medical device can be provided with regions of relatively greater axial flexibility and/or with regions of relatively greater axial stiffness. As shown in Fig. 3, a region of relatively greater axial flexibility is formed by omitting the connecting elements 114 to create a flexible segment or region. Fig. 3 shows a device having a relatively flexible circumferential region in which connecting elements 114 have been removed along a line extending lengthwise on the device. The reduction in connecting elements renders the device more flexible in the "removed" region when compared to regions having a relatively greater number of connecting elements 114. Figure 3 shows that all connecting elements are omitted from the relatively flexible region, though arrangements in which a number of connecting elements are selectively omitted - i.e., less than all connecting elements are omitted -- are possible. For example, the connecting elements may be omitted longitudinally from one end of the device to the other, or for a portion of such longitudinal segment. In a further alternative arrangement, the connecting elements may be omitted circumferentially, that is, at locations corresponding to a pattern along the circumference of the device. Likewise, the connecting elements can be omitted from a combination of lengthwise and circumferential locations. In yet another arrangement, the connecting elements is omitted in two locations, across the device from each other, substantially 180° apart.

    [0031] Figure 4 shows an example in which the dimensions of the connecting elements 114, and in particular, the width, depth (or both) of such elements can be reduced in the relatively more flexible regions of the device. Fig. 4 specifically shows a segment along the surface of a device in which connecting elements 114 (a) has a relatively smaller width dimension than the width dimension of connecting elements 114 (b), and thus connecting elements 114 (a) would be expected to exhibit greater flexibility than connecting elements 114 (b). The depth of the connecting elements 114 (a) can be varied in comparison to the depth of connecting elements 114 (b) (or in relation to other connecting elements 114 of the device not shown in the segment) or the amplitude of the connecting element. Furthermore, it should be appreciated that the width, depth, or both of other components, such as the hoop member 106, can also be varied.

    [0032] Alternatively, the width and/or depth, the amplitude, path length, or combination of any such factors concerning the design of connecting elements 114 can be modified in one circumferential region or segment of the device to provide a region that is relatively axially stiffer than a second circumferential region of the device (or on the other hand, modified to provide for a relatively axially flexible region). For example, connecting elements 114 possessing an increased width and/or depth dimension (when compared to the connecting elements 114 in a second region of the device), will exhibit increased resistance to bending, and thus, exhibits increased stiffness over at least a portion of the surface of the device. Also, the location where the connecting elements join to adjacent hoop members 106 can be selected to modify the flexibility or rigidity of a device segment.

    [0033] There are other ways in which the implant can be provided with a circumferential region that is relatively more flexible and/or stiffer than other circumferential regions of the device. For example, the wall thickness of the implant, in a given segment can be larger than in a second region of the implant. Fig. 5 depicts such an arrangement, where region A is radially thicker than region B. It would be expected that the device would be less flexible in thicker region A. Likewise, the wall thickness of the implant in region B renders the device more flexible there than in region A. In this arrangement, the connecting elements 114, hoop components 106, radial strut members 108, and radial arc members 110, flexible struts 116, and flexible arc members 118 in the selected segment can be made either radially thicker or thinner than in a second region of the implant. An implant with varying regions of wall thickness can be produced by extruding a device though a dye exhibiting the desired different wall thickness regions. With this arrangement, a portion of the device, and components comprising same, as described above, will be thicker or thinner, that is, stiffer or more flexible, depending on the dimensions of the dye. Alternatively, a portion of the device can be made thinner by machining or polishing its surface; to create a relatively thinner, and thereby more flexible, region of the device. This works particularly well when the device is produced from a metallic material.

    [0034] In another example, shown in FIG. 6, the amplitude of the hoop components 106 varies over a 180° section of the device. Starting at a location on the device circumference, designated 0°, where the amplitude of the hoop components are at their smallest (A1), and then traversing around the circumference 180°, the amplitude of the hoop component 106 (a) increases over the circumference, with the amplitude of hoop components 106(b) to 106 (f) gradually increasing, and is largest at hoop component 106 (g) (A4). The backside of the device, not shown in FIG. 6, is substantially symmetric with what is shown in the figure. In this arrangement, smaller amplitude hoop components, such as 106 (a) and 106(b), exhibit relatively greater flexibility than larger amplitude hoop components, such as 106 (f) and 106 (g).

    [0035] In yet another example shown in Figure 7, the relatively more flexible region of the device is provided with connecting elements 114b that are longer than the length of the connecting elements 114a found in a second less flexible region of the device. The connecting elements in the second, less flexible region of the device that are relatively straighter, that is, with smaller, whereas in the relatively more flexible sections, the connecting elements exhibit a relatively more tortuous path leading to larger path length, which, thereby can exhibit a greater degree of flexibility. It should be understood that the connecting elements opposite the connecting elements 114b may be substantially the same in kind as elements 114b, and the connecting elements opposite the connecting elements 114a may be substantially the same in kind as elements 114a.

    [0036] FIGS. 8A-8F illustrate arrangements for positioning regions of relatively greater flexibility and regions of relatively greater stiffness around the circumference of the device. In FIG. 8A, the device is provided with a single region of relatively greater axial stiffness in relation to the remainder of the circumference. In FIG. 8B, the device is provided with a single region of relatively greater axial flexibility in relation to the remainder of the circumference. According to the present invention, a stiffening rod that runs longitudinally through a majority of the device's length can provide a degree of stiffness that is greater than exhibited by the remainder of the device's circumference. FIG. 8B shows a device provided with a single region of relatively lesser axial stiffness in relation to the remainder of the device circumference. The region of relatively greater axial stiffness could predominate the device circumference as depicted in Fig. 8B, or it could comprise just a minor portion of the device circumference.

    [0037] FIG. 8C shows a device in which regions of relatively greater axial stiffness are positioned 180° apart from each other. FIG. 8E shows a device in which regions of relatively greater and relatively higher axial stiffness alternate at 90° orientations. FIG. 8D shows a device in which regions of relatively lower axial stiffness are positioned 180° apart from each other. FIG. 8F shows a device in which axial stiffness increases from high to low across a 90 degree section as device circumference is traversed, or conversely, in which axial flexibility increases from low to high. Any of the aforementioned embodiments can be arranged in the patterns described in the Figure 8 series.

    [0038] The device can be used with dissimilar branch arrangements, such as a vessel anatomy having a main branch bend and a side branch off the outside of the main branch bend shown in Figure 9, and a vessel anatomy having a main branch bend and a side branch off the inside bend on the main branch shown in Figure 10. By rotating the device it will orient for deployment in the main branch or the side branch ostium, as called for in the course of treatment.

    [0039] The device may be fabricated by laser machining of a material into a cylindrical device. Suitable materials that can be used to fabricate the stent include, cobalt chromium alloy and other non-ferrous alloys, such as Cobalt and Nickel based alloys, Nickel Titanium alloys, stainless steel, other ferrous metal alloys, refractory metals, refractory metal alloys, titanium and titanium based alloys. The stent may also be fabricated from a ceramic or polymer material.

    [0040] Therapeutic or pharmaceutical agents may be applied to the device, such as in the form of a drug or drug-eluting layer, or surface treatment after the device has been formed. In a preferred embodiment, the therapeutic and pharmaceutical agents may include any one or more of the following: antiproliferative/antimitotic agents including natural products such as vinca alkaloids (i.e. vinblastine, vincristine, and vinorelbine), paclitaxel, epidipodophyllotoxins (i.e. etoposide, teniposide), antibiotics (dactinomycin (actinomycin D) daunorubicin, doxorubicin and idarubicin), anthracyclines, mitoxantrone, bleomycins, plicamycin (mithramycin) and mitomycin, enzymes (L-asparaginase which systemically metabolizes L-asparagine and deprives cells which do not have the capacity to synthesize their own asparagine); antiplatelet agents such as G(GP) llb/llla inhibitors and vitronectin receptor antagonists; antiproliferative/antimitotic alkylating agents such as nitrogen mustards (mechlorethamine, cyclophosphamide and analogs, melphalan, chlorambucil), ethylenimines and methylmelamines (hexamethylmelamine and thiotepa), alkyl sulfonates-busulfan, nirtosoureas (carmustine (BCNU) and analogs, streptozocin), trazenes - dacarbazinine (DTIC); antiproliferative/antimitotic antimetabolites such as folic acid analogs (methotrexate), pyrimidine analogs (fluorouracil, floxuridine, and cytarabine), purine analogs and related inhibitors (mercaptopurine, thioguanine, pentostatin and 2-chlorodeoxyadenosine {cladribine}); platinum coordination complexes (cisplatin, carboplatin), procarbazine, hydroxyurea, mitotane, aminoglutethimide; hormones (i.e. estrogen); anticoagulants (heparin, synthetic heparin salts and other inhibitors of thrombin); fibrinolytic agents (such as tissue plasminogen activator, streptokinase and urokinase), aspirin, dipyridamole, ticlopidine, clopidogrel, abciximab; antimigratory; antisecretory (breveldin); antiinflammatory: such as adrenocortical steroids (cortisol, cortisone, fludrocortisone, prednisone, prednisolone, 6α-methylprednisolone, triamcinolone, betamethasone, and dexamethasone), non-steroidal agents (salicylic acid derivatives i.e. aspirin; para-aminophenol derivatives i.e. acetominophen; indole and indene acetic acids (indomethacin, sulindac, and etodalac), heteroaryl acetic acids (tolmetin, diclofenac, and ketorolac), arylpropionic acids (ibuprofen and derivatives), anthranilic acids (mefenamic acid, and meclofenamic acid), enolic acids (piroxicam, tenoxicam, phenylbutazone, and oxyphenthatrazone), nabumetone, gold compounds (auranofin, aurothioglucose, gold sodium thiomalate); immunosuppressives: (cyclosporine, tacrolimus (FK-506), sirolimus (rapamycin), azathioprine, mycophenolate mofetil); angiogenic agents: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF); angiotensin receptor blockers; nitric oxide donors; anti-sense oligionucleotides and combinations thereof; cell cycle inhibitors, mTOR inhibitors, and growth factor receptor signal transduction kinase inhibitors; retenoids; cydin/CDK inhibitors; HMG co-enzyme reductase inhibitors (statins); and protease inhibitors.

    [0041] It is contemplated that various combinations or sub combinations of the specific embodiments may be made and still fall within the scope of the invention. For example, the embodiments variously shown to be cardiac stents may be modified to treat other vessels or lumens in the body, in particular other regions of the body where vessels or lumen need to be supported. This may include, for example, the coronary, vascular, non-vascular and peripheral vessels and ducts.


    Claims

    1. An implantable medical device comprising:

    a tubular configuration defined by interconnected elements, the tubular configuration having first and second open ends and a length dimension extending between the ends, wherein the tubular configuration of the device has a first circumferential segment substantially extending the length of the device, the first circumferential segment exhibiting relatively greater axial stiffness and a second circumferential segment substantially extending the length of the device, the second circumferential segment exhibiting relatively greater axial flexibility; characterized in that the segment of relatively greater stiffness includes a longitudinally extending stiffening rod extending substantially the entire length of the device.


     
    2. The implantable medical device of claim 1 wherein the interconnected elements are provided in a serpentine course.
     
    3. The medical device of claim 1 wherein the interconnected elements are further comprised of a plurality of curved elements arrayed substantially lengthwise and circumferentially about the device, wherein the elements that neighbor in the length direction are linked with each other by connecting elements, the second circumferential segment is provided with a lesser number of connecting elements when compared to the number of connecting elements provided in the first circumferential segment.
     
    4. The medical device of claim 1 wherein the device is provided with two circumferential segments of relatively greater stiffness and two circumferential segments of relatively greater flexibility in which the relatively greater flexible segments and the relatively stiffer segments are positioned on the device in an alternating arrangement.
     
    5. The device of claim 1 wherein the segment of relatively greater stiffness is the predominant portion of the device wall periphery.
     
    6. The device of claim 1 wherein the segment of relatively greater stiffness is the minor portion of the device wall periphery.
     
    7. The implantable medical device of claim 1, wherein the plurality of interconnected elements comprise a plurality of components comprised of a plurality of hoop components (106) being formed as a continuous series of substantially longitudinally oriented radial strut members (108) and a plurality of radial arc members (110) connecting circumferentially adjacent radial struts (108), and a plurality of connecting elements (114) having first and second ends, which first and second ends bridge adjacent radial strut members (108) and/or radial arc members (110).
     
    8. The medical device of claim 7 wherein the second circumferential segment is provided with a lesser number of connecting elements (114) when compared to the number of connecting elements (114) provided in the first circumferential segment.
     
    9. The medical device of claim 7 wherein the device is provided with two circumferential segments of relatively greater axial stiffness and two circumferential segments of relatively greater axial flexibility in which the relatively greater flexible segments and the relatively stiffer segments are positioned on the device in an alternating arrangement on the device circumference.
     
    10. The medical device of claim 9 wherein the two circumferential segments of relatively greater axial flexibility are provided with a lesser number of connecting elements (114) when compared to the number of connecting elements (114) provided in the two circumferential segments of relatively greater axial stiffness.
     
    11. The medical device of claim 9 wherein the relatively flexible segments are positioned approximately 180° across the device.
     
    12. The medical device of claim 9 wherein the circumferential segments of relatively greater axial stiffness are positioned approximately 180° across the device.
     
    13. The medical device of claim 11 wherein the circumferential segments of relatively greater flexibility is provided with a lesser number of connecting elements (114) when compared to the number of connecting elements (114) provided in the circumferential segments of relatively greater axial stiffness.
     
    14. The medical device of claim 11 wherein at least one of the two relatively flexible segments (114) omits connecting elements in a discernible pattern.
     
    15. The medical device of claim 7 wherein the connecting elements (114) located in the second segment of relatively greater flexibility are provided with at least one relatively smaller dimension when compared to the dimensions of the connecting elements (114) located in the first segment of relatively greater stiffness.
     
    16. The medical device of claim 15 wherein at least one of the connecting elements (114) of the second circumferential segment of relatively greater flexibility is provided with at least one of a reduced width or radial thickness dimension for at least a portion of its length when compared to the width or depth dimension of the connecting element (114) of the first relatively stiffer segment.
     
    17. The medical device of claim 9 wherein the two circumferential segments of relatively greater axial flexibility include connecting elements (114) in which at least one dimension is relatively smaller when compared to the comparable dimensions of the connecting elements (114) in the two circumferential segments of relatively greater axial stiffness.
     
    18. The medical device of claim 17 wherein the two circumferential segments of relatively greater axial flexibility include connecting elements (114) which are provided with at least one of a reduced width or radial thickness dimension for at least a portion of its length when compared to the width or depth dimension of the connecting elements (114) of the circumferential segments of relatively greater axial stiffness.
     
    19. The medical device of claim 9 wherein the circumferential segments of relatively greater stiffness are provided with connecting elements (114) having at least one dimension that is relatively larger when compared to the comparable dimensions of the connecting elements (114) in the circumferential segments of relatively greater axial flexibility.
     
    20. The medical device of claim 19 wherein the circumferential segments of relatively greater axial stiffness include connecting elements (114) which are provided with at least one of a greater width or radial thickness dimension for at least a portion of its length when compared to the width or depth dimension of the connecting elements (114) of the circumferential segments of relatively greater axial flexibility.
     
    21. The medical device of claim 7 wherein the at least one of the connecting elements (114) of the second segment of relatively greater flexibility is provided with a path length that is relatively greater than the path length of the connecting elements (114) in the segment of relatively greater stiffness.
     
    22. The medical device of claim 9 wherein the circumferential segments of relatively greater axial flexibility are provided with connecting elements (114) having a path length that is relatively greater than the path length of the connecting elements (114) in the circumferential segments of relatively greater stiffness.
     
    23. The medical device of claim 9 wherein the two circumferential segments of relatively greater axial stiffness are provided with connecting elements (114) having a path length that is relatively shorter than the path length of the connecting elements (114) in the segment of relatively greater flexibility.
     
    24. The medical device of claim 7 wherein the hoop components (106) exhibit amplitude that varies from relatively smallest amplitude (106a) to relatively largest amplitude (106g).
     
    25. The medical device of claim 24 wherein amplitude of the hoop components (106) varies incrementally from relatively smallest amplitude (106a) to relatively largest amplitude (106g).
     
    26. The medical device of claim 7 wherein the first circumferential segment of relatively greater axial stiffness is provided with a wall thickness that is relatively greater than the wall thickness of the second circumferential segment of relatively greater axial flexibility.
     
    27. The medical device of claim 9 wherein the circumferential segments of relatively greater axial stiffness are provided with a relatively greater wall thickness than the wall thickness of the two circumferential segments of relatively greater flexibility.
     
    28. The medical device of claim 9 wherein the circumferential segments of relatively greater axial flexibility are provided with a wall thickness that is relatively smaller than the wall thickness of the circumferential segments of relatively greater stiffness.
     
    29. The medical device of claim 17, 19, 22, 23, 27 or 28, wherein the circumferential segments of greater axial flexibility are positioned approximately 180° across the device.
     
    30. The medical device of claim 17, 19, 22, 23, 27 or 28, wherein the circumferential segments of greater axial stiffness are positioned approximately 180° across the device.
     


    Ansprüche

    1. Implantierbare medizinische Vorrichtung, welche Folgendes umfasst:

    eine röhrenförmige Anordnung, welche durch miteinander verbundene Elemente definiert ist, wobei die röhrenförmige Anordnung ein erstes und ein zweites offenes Ende und eine Längenabmessung aufweist, welche sich zwischen den Enden erstreckt, wobei die röhrenförmige Anordnung der Vorrichtung ein erstes Umfangssegment, welches sich im Wesentlichen über die Länge der Vorrichtung erstreckt, wobei das erste Umfangssegment eine verhältnismäßig größere axiale Steifigkeit aufweist, und ein zweites Umfangssegment aufweist, welches sich im Wesentlichen über die Länge der Vorrichtung erstreckt, wobei das zweite Umfangssegment eine verhältnismäßig größere axiale Flexibilität aufweist; dadurch gekennzeichnet, dass das Segment verhältnismäßig größerer Steifigkeit eine sich längs erstreckende Versteifungsstange aufweist, welche sich im Wesentlichen über die gesamte Länge der Vorrichtung erstreckt.


     
    2. Implantiere medizinische Vorrichtung nach Anspruch 1, wobei die miteinander verbundenen Elemente mit einem gewundenen Verlauf versehen sind.
     
    3. Medizinische Vorrichtung nach Anspruch 1, wobei die miteinander verbundenen Elemente weiter mehrere gekrümmte Elemente umfassen, welche im Wesentlichen der Länge nach und peripher über die Vorrichtung angeordnet sind, wobei die Elemente, welche in der Längsrichtung benachbart sind, miteinander über Verbindungselemente verbunden sind, wobei das zweite Umfangssegment mit einer kleineren Anzahl von Verbindungselementen versehen ist im Vergleich zu der Anzahl von Verbindungselementen, mit welchen das erste Umfangssegment versehen ist.
     
    4. Medizinische Vorrichtung nach Anspruch 1, wobei die Vorrichtung mit zwei Umfangssegmenten verhältnismäßig größerer Steifigkeit und zwei Umfangssegmenten verhältnismäßig größerer Flexibilität versehen ist, wobei die verhältnismäßig flexibleren Segmente und die verhältnismäßig steiferen Segmente in einer alternierenden Weise auf der Vorrichtung angeordnet sind.
     
    5. Vorrichtung nach Anspruch 1, wobei das Segment verhältnismäßig größerer Steifigkeit den überwiegenden Teil der Wandungsperipherie der Vorrichtung ausmacht.
     
    6. Vorrichtung nach Anspruch 1, wobei das Segment verhältnismäßig größerer Steifigkeit den geringeren Teil der Wandungsperipherie der Vorrichtung ausmacht.
     
    7. Implantierbare medizinische Vorrichtung nach Anspruch 1, wobei die mehreren miteinander verbundenen Elemente mehrere Komponenten umfassen, welche mehrere Schlaufenkomponenten (106), welche als eine kontinuierliche Folge von im Wesentlichen in Längsrichtung orientierten radialen Strebenelementen (108) und mehrere radiale Bogenelementen (110), welche in Umfangsrichtung benachbarte radiale Streben (108) verbinden, gebildet sind und mehrere Verbindungselemente (114) umfassen, welche erste und zweite Enden aufweisen, wobei die ersten und zweiten Enden benachbarte radiale Strebenelemente (108) und/oder radiale Bogenelemente (110) überbrücken.
     
    8. Medizinische Vorrichtung nach Anspruch 7, wobei das zweite Umfangssegment mit einer kleineren Anzahl von Verbindungselementen (114) versehen ist im Vergleich zu der Anzahl von Verbindungselementen (114), mit welchen das erste Umfangssegment versehen ist.
     
    9. Medizinische Vorrichtung nach Anspruch 7, wobei die Vorrichtung mit zwei Umfangssegmenten verhältnismäßig größerer axialer Steifigkeit und zwei Umfangssegmenten verhältnismäßig größerer axialer Flexibilität versehen ist, wobei die verhältnismäßig flexibleren Segmente und die verhältnismäßig steiferen Segmente auf der Vorrichtung in einer alternierenden Weise auf dem Vorrichtungsumfang angeordnet sind.
     
    10. Medizinische Vorrichtung nach Anspruch 9, wobei die zwei Umfangssegmente verhältnismäßig größerer axialer Flexibilität mit einer kleineren Anzahl von Verbindungselementen (114) versehen sind im Vergleich zu der Anzahl von Verbindungselementen (114), mit welchen die zwei Umfangssegmente verhältnismäßig größerer axialer Steifigkeit versehen sind.
     
    11. Medizinische Vorrichtung nach Anspruch 9, wobei die verhältnismäßig flexiblen Segmente um ungefähr 180° über die Vorrichtung angeordnet sind.
     
    12. Medizinische Vorrichtung nach Anspruch 9, wobei die Umfangssegmente verhältnismäßig größerer axialer Steifigkeit um ungefähr 180° über die Vorrichtung angeordnet sind.
     
    13. Medizinische Vorrichtung nach Anspruch 11, wobei die Umfangssegmente verhältnismäßig größerer Flexibilität mit einer kleineren Anzahl von Verbindungselementen (114) versehen sind im Vergleich zu der Anzahl von Verbindungselementen (114), mit welchen die Umfangssegmente verhältnismäßig größerer axialer Steifigkeit versehen sind.
     
    14. Medizinische Vorrichtung nach Anspruch 11, wobei zumindest eines der zwei verhältnismäßig flexiblen Segmente (114) in einem erkennbaren Muster Verbindungselemente auslässt.
     
    15. Medizinische Vorrichtung nach Anspruch 7, wobei die Verbindungselemente (114), welche sich in dem zweiten Segment verhältnismäßig größerer Flexibilität befinden, mit zumindest einer verhältnismäßig kleineren Abmessung versehen sind im Vergleich zu den Abmessungen der Verbindungselemente (114), welche sich in dem ersten Segment verhältnismäßig größerer Steifigkeit befinden.
     
    16. Medizinische Vorrichtung nach Anspruch 15, wobei zumindest eines der Verbindungselemente (114) des zweiten Umfangssegments verhältnismäßig größerer Flexibilität über zumindest einen Teilbereich seiner Länge mit einer verringerten Breiten- und/oder radialen Dickenabmessung versehen ist im Vergleich zu der Breiten- oder Tiefenabmessung der Verbindungselemente (114) des ersten verhältnismäßig steiferen Segments.
     
    17. Medizinische Vorrichtung nach Anspruch 9, wobei die zwei Umfangssegmente verhältnismäßig größerer axialer Flexibilität Verbindungselemente (114) aufweisen, bei welchen zumindest eine Abmessung verhältnismäßig kleiner ist im Vergleich zu den vergleichbaren Abmessungen der Verbindungselemente (114) in den zwei Umfangssegmenten verhältnismäßig größerer axialer Steifigkeit.
     
    18. Medizinische Vorrichtung nach Anspruch 17, wobei die zwei Umfangssegmente verhältnismäßig größerer axialer Flexibilität Verbindungselemente (114) aufweisen, welche über zumindest einen Teilbereich ihrer Länge mit einer verringerten Breiten- und/oder radialen Dickenabmessung versehen sind im Vergleich zu der Breiten- oder Dickenabmessung der Verbindungselemente (114) der Umfangssegmente verhältnismäßig größerer axialer Steifigkeit.
     
    19. Medizinische Vorrichtung nach Anspruch 9, wobei die Umfangssegmente verhältnismäßig größerer Steifigkeit mit Verbindungselementen (114) versehen sind, welche zumindest eine Abmessung aufweisen, welche verhältnismäßig größer ist im Vergleich zu den vergleichbaren Abmessungen der Verbindungselemente (114) in den Umfangssegmenten verhältnismäßig größerer axialer Flexibilität.
     
    20. Medizinische Vorrichtung nach Anspruch 19, wobei die Umfangssegmente verhältnismäßig größerer axialer steifigkeit Verbindungselemente (114) aufweisen, welche über zumindest einen Teilbereich ihrer Länge mit einer größeren Breiten- und/oder radialen Dickenabmessungen versehen sind im Vergleich zu der Breiten- oder Dickenabmessung der Verbindungselemente (114) der Umfangssegmente verhältnismäßig größerer axialer Flexibilität.
     
    21. Medizinische Vorrichtung nach Anspruch 7, wobei das zumindest eine der Verbindungselemente (114) des zweiten Segments verhältnismäßig größerer Flexibilität mit einer Pfadlänge versehen ist, welche verhältnismäßig größer als die Pfadlänge der Verbindungselemente (114) in dem Segment verhältnismäßig größerer Steifigkeit ist.
     
    22. Medizinische Vorrichtung nach Anspruch 9, wobei die Umfangssegmente verhältnismäßig größerer axialer Flexibilität mit Verbindungselementen (114) versehen sind, die eine Pfadlänge aufweisen, welche verhältnismäßig größer als die Pfadlänge der Verbindungselemente (114) in den Umfangssegmenten verhältnismäßig größerer Steifigkeit ist.
     
    23. Medizinische Vorrichtung nach Anspruch 9, wobei die zwei Umfangssegmente verhältnismäßig größerer Steifigkeit mit Verbindungselementen (114) versehen sind, welche eine Pfadlänge aufweisen, welche verhältnismäßig kürzer als die Pfadlänge der Verbindungselemente (114) in dem Segment verhältnismäßig größerer Flexibilität ist.
     
    24. Medizinische Vorrichtung nach Anspruch 7, wobei die Schlaufenkomponenten (106) eine Amplitude aufweisen, welche sich von einer verhältnismäßig kleinsten Amplitude (106a) zu einer verhältnismäßig größten Amplitude (106g) ändert.
     
    25. Medizinische Vorrichtung nach Anspruch 24, wobei sich die Amplitude der Schlaufenkomponenten (106) zunehmend von der verhältnismäßig kleinsten Amplitude (106a) zu der verhältnismäßig größten Amplitude (106g) ändert.
     
    26. Medizinische Vorrichtung nach Anspruch 7, wobei das erste Umfangssegment verhältnismäßig größerer axialer Steifigkeit mit einer Wandstärke versehen ist, welche verhältnismäßig größer als die Wandstärke des zweiten Umfangssegments verhältnismäßig größerer axialer Flexibilität ist.
     
    27. Medizinische Vorrichtung nach Anspruch 9, wobei die Umfangssegmente verhältnismäßig größerer axialer Steifigkeit mit einer verhältnismäßig größeren Wandstärke versehen sind als die Wandstärke der zwei Umfangssegmente verhältnismäßig größerer Flexibilität.
     
    28. Medizinische Vorrichtung nach Anspruch 9, wobei die Umfangssegmente verhältnismäßig größerer axialer Flexibilität mit einer Wandstärke versehen sind, welche verhältnismäßig kleiner als die Wandstärke der Umfangssegmente verhältnismäßig größerer Steifigkeit ist.
     
    29. Medizinische Vorrichtung nach Anspruch 17, 19, 22, 23, 27 oder 28, wobei die Umfangssegmente größerer axialer Flexibilität um ungefähr 180° über die Vorrichtung angeordnet sind.
     
    30. Medizinische Vorrichtung nach Anspruch 17, 19, 22, 23, 27 oder 28, wobei die Umfangssegmente größerer axialer Steifigkeit um ungefähr 180° über die Vorrichtung angeordnet sind.
     


    Revendications

    1. Dispositif médical implantable, comprenant :

    une configuration tubulaire définie par des éléments interconnectés, la configuration tubulaire ayant une première et une seconde extrémité ouverte et une dimension longitudinale s'étendant entre les extrémités, dans lequel la configuration tubulaire du dispositif a un premier segment circonférentiel s'étendant sensiblement sur la longueur du dispositif, le premier segment circonférentiel présentant une rigidité axiale relativement supérieure et un second segment circonférentiel s'étendant sensiblement sur la longueur du dispositif, le second segment circonférentiel présentant une flexibilité axiale relativement supérieure ; caractérisé en ce que le segment de rigidité relativement supérieure comprend une tige de raidissement longitudinale s'étendant sensiblement sur la longueur tout entière du dispositif.


     
    2. Dispositif médical implantable selon la revendication 1, dans lequel les éléments interconnectés sont disposés selon une conformation ondulée.
     
    3. Dispositif médical selon la revendication 1, dans lequel les éléments interconnectés comprennent en outre une pluralité d'éléments incurvés arrangés sensiblement dans le sens de la longueur et de manière circonférentielle autour du dispositif, dans lequel les éléments avoisinants dans le sens de la longueur sont reliés les uns aux autres par des éléments de connexion, et le second segment circonférentiel est doté d'un nombre moindre d'éléments de connexion par rapport aux éléments de connexion apportés dans le premier segment circonférentiel.
     
    4. Dispositif médical selon la revendication 1, dans lequel le dispositif est doté de deux segments circonférentiels de rigidité relativement supérieure et deux segments circonférentiels de flexibilité relativement supérieure, dans lequel les segments de flexibilité relativement supérieure et les segments de rigidité relativement supérieure sont disposés de manière alternée sur le dispositif.
     
    5. Dispositif selon la revendication 1, dans lequel le segment de rigidité relativement supérieure forme la partie majeure de la périphérie de la paroi du dispositif.
     
    6. Dispositif selon la revendication 1, dans lequel le segment de rigidité relativement supérieure forme la partie mineure de la périphérie de la paroi du dispositif.
     
    7. Dispositif médical implantable selon la revendication 1, dans lequel la pluralité d'éléments interconnectés comprend une pluralité de composants comprenant une pluralité de composants de cerclage (106) en forme d'une série continue d'éléments radiaux d'étayage (108) orientés dans un sens sensiblement longitudinal, et une pluralité d'éléments radiaux arqués (110) reliant de manière circonférentielle les étais radiaux (108) adjacents, et une pluralité d'éléments de connexion (114) présentant une première et une seconde extrémité, lesdites premières et secondes extrémités reliant les éléments radiaux d'étayage (108) et/ou les éléments radiaux arqués (110) adjacents.
     
    8. Dispositif médical selon la revendication 7, dans lequel le second segment circonférentiel est doté d'un nombre moindre d'éléments de connexion (114) comparativement au nombre d'éléments de connexion (114) apportés dans le premier élément circonférentiel.
     
    9. Dispositif médical selon la revendication 7, dans lequel le dispositif est doté de deux segments circonférentiels présentant une rigidité axiale relativement supérieure et de deux segments circonférentiels présentant une flexibilité axiale relativement supérieure, dans lequel les segments relativement plus flexibles et les segments relativement plus rigides sont disposés de manière alternée sur la circonférence du dispositif.
     
    10. Dispositif médical selon la revendication 9, dans lequel les deux segments circonférentiels de flexibilité axiale relativement supérieure sont dotés d'un nombre moindre d'éléments de connexion (114) comparativement au nombre d'éléments de connexion (114) apportés dans les deux segments circonférentiels de rigidité axiale relativement supérieure.
     
    11. Dispositif médical selon la revendication 9, dans lequel les segments relativement flexibles sont disposés à environ 180° à travers le dispositif.
     
    12. Dispositif médical selon la revendication 9, dans lequel les segments circonférentiels de rigidité axiale relativement supérieure sont disposés à environ 180° à travers le dispositif.
     
    13. Dispositif médical selon la revendication 11, dans lequel les segments circonférentiels de flexibilité axiale relativement supérieure sont dotés d'un nombre moindre d'éléments de connexion (114) comparativement au nombre d'éléments de connexion (114) disposés dans les segments circonférentiels de rigidité axiale relativement supérieure.
     
    14. Dispositif médical selon la revendication 11, dans lequel au moins un des deux segments relativement flexibles (114) présente un motif discernable d'omission d'éléments de connexion.
     
    15. Dispositif médical selon la revendication 7, dans lequel les éléments de connexion (114) disposés dans le second segment de flexibilité relativement supérieure sont dotés d'au moins une dimension relativement inférieure comparativement aux dimensions des éléments de connexion (114) disposés dans le premier segment de rigidité relativement supérieure.
     
    16. Dispositif médical selon la revendication 15, dans lequel au moins un des éléments de connexion (114) du second segment circonférentiel de flexibilité relativement supérieure présente au moins une dimension réduite parmi la largeur ou l'épaisseur radiale sur au moins une partie de sa longueur comparativement à la largeur ou la profondeur des éléments de connexion (114) du premier segment relativement plus rigide.
     
    17. Dispositif médical selon la revendication 9, dans lequel les deux segments circonférentiels de flexibilité axiale relativement supérieure comprennent des éléments de connexion (114) dans lesquels au moins une dimension est relativement inférieure comparativement aux dimensions comparables des éléments de connexion (114) dans les deux segments circonférentiels de rigidité axiale relativement supérieure.
     
    18. Dispositif médical selon la revendication 17, dans lequel les deux segments circonférentiels de flexibilité axiale relativement supérieure comprennent des éléments de connexion (114) qui présentent au moins une dimension réduite parmi la largeur ou l'épaisseur radiale sur au moins une partie de leur longueur comparativement à la largeur ou la profondeur des éléments de connexion (114) des segments circonférentiels de rigidité axiale relativement supérieure.
     
    19. Dispositif médical selon la revendication 9, dans lequel les segments circonférentiels de rigidité relativement supérieure sont dotés d'éléments de connexion (114) présentant au moins une dimension relativement supérieure comparativement aux dimensions comparables des éléments de connexion (114) dans les segments circonférentiels de flexibilité axiale relativement supérieure.
     
    20. Dispositif médical selon la revendication 19, dans lequel les segments circonférentiels de rigidité axiale relativement supérieure comprennent des éléments de connexion (114) qui présentent au moins une dimension supérieure parmi la largeur ou l'épaisseur radiale sur au moins une partie de leur longueur comparativement à la largeur ou la profondeur des éléments de connexion (114) des segments circonférentiels de flexibilité axiale relativement supérieure.
     
    21. Dispositif médical selon la revendication 7, dans lequel l'au moins un des éléments de connexion (114) du second segment de flexibilité relativement supérieure présente une longueur de parcours relativement supérieure à la longueur de parcours des éléments de connexion (114) dans le segment de rigidité relativement supérieure.
     
    22. Dispositif médical selon la revendication 9, dans lequel les segments circonférentiels de flexibilité axiale relativement supérieure sont munis d'éléments de connexion (114) présentant une longueur de parcours relativement supérieure à la longueur de parcours des éléments de connexion (114) dans les segments circonférentiels de rigidité relativement supérieure.
     
    23. Dispositif médical selon la revendication 9, dans lequel les deux segments de rigidité axiale relativement supérieure sont munis d'éléments de connexion (114) présentant une longueur de parcours relativement inférieure à la longueur de parcours des éléments de connexion (114) dans le segment de flexibilité relativement supérieure.
     
    24. Dispositif médical selon la revendication 7, dans lequel les composants de cerclage (106) présentent une ampleur variant de l'ampleur relativement la plus petite (106a) à l'ampleur relativement la plus grande (106g).
     
    25. Dispositif médical selon la revendication 24, dans lequel l'ampleur des composants de cerclage (106) varie progressivement de l'ampleur relativement la plus petite (106a) à l'ampleur relativement la plus grande (106g).
     
    26. Dispositif médical selon la revendication 7, dans lequel le premier segment circonférentiel de rigidité axiale relativement supérieure est doté d'une épaisseur de paroi qui est relativement supérieure à l'épaisseur de paroi du second segment circonférentiel de flexibilité axiale relativement supérieure.
     
    27. Dispositif médical selon la revendication 9, dans lequel les segments circonférentiels de rigidité axiale relativement supérieure sont dotés d'une épaisseur de paroi relativement supérieure à l'épaisseur de paroi des deux segments circonférentiels de flexibilité relativement supérieure.
     
    28. Dispositif médical selon la revendication 9, dans lequel les segments circonférentiels de flexibilité axiale relativement supérieure sont dotés d'une épaisseur de paroi relativement inférieure à l'épaisseur de paroi des segments circonférentiels de rigidité relativement supérieure.
     
    29. Dispositif médical selon la revendication 17, 19, 22, 23, 27 ou 28, dans lequel les segments circonférentiels de flexibilité axiale supérieure sont disposés à environ 180° à travers le dispositif.
     
    30. Dispositif médical selon la revendication 17, 19, 22, 23, 27 ou 28, dans lequel les segments circonférentiels de rigidité axiale supérieure sont disposés à environ 180° à travers le dispositif.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description