Intravascular occlusion devices

Abstract

The present invention relates to an intravascular occlusion device used to occlude a lumen of the vasculature and induce tissue ischemia or necrosis to treat certain medical conditions, such as deformed, bleeding, or occluded blood vessels. The occlusion device includes a deformable sleeve that is displaceable between a contracted state and an expanded state, and a conical array of cantilevered arms extending from the distal end of the sleeve and converging toward a distal tip, defining a first hemostatic valve around the distal end of the sleeve. The distal end of the sleeve is at least partially covered with a polymeric, fluid-impermeable membrane to provide a seal that prevents fluid flow through the occlusion device. The internal valve provides hemostatic effect regardless of the initial direction of blood flow and allows for distal intravascular delivery of surgical instruments, such as catheters, which can be manipulated and used to deliver therapeutic agents, such as liquids or small particle emboli.

Description

[Technical Field]

[0001] The present invention relates to intravascular occlusion devices, particularly for use in occluding lumens in the vascular system to treat certain medical conditions, and more particularly to occlusion devices for the appropriate treatment of deformed, bleeding, or occluded blood vessels to induce tissue ischemia or necrosis. [Background technology]

[0002] There are many clinical situations where it is necessary to occlude blood vessels such as arteries and veins. Inducing necrosis or tissue ischemia is the desired effect in certain medical conditions, such as uterine fibroids, prostatic hyperplasia, benign or malignant renal tumors, and liver parenchyma, when attempting to induce compensatory thickening in intact, non-embolized livers in the weeks prior to liver surgery. The number of indications and procedures performed for the purpose of distal embolization to induce ischemia and necrosis is increasing.

[0003] Additionally, certain cancer treatments require drug delivery to arteries and veins. By occluding flow proximally, flow can be redirected (flow redistribution) away from distal vessels and toward the tumor. If drug delivery is then performed through the occluded proximal artery, for example, in transarterial chemoembolization (TACE), delivered through an occlusion catheter (bTACE, balloon-occluded TACE), more distal and complete penetration of drug delivery can be achieved.

[0004] Endovascular occlusion has been performed for over 60 years. In recent decades, major technological advances have improved the techniques used and led to the development of a variety of devices for different conditions and an increasing number of indications. Early embolic materials included glass particles, high-temperature contrast agents, paraffin, fibrin, and tissue fragments such as muscle fibers and blood clots. Current occlusion materials include metal devices, small particles, and liquid materials, and can be adapted to proximal or distal occlusions, high-flow and low-flow situations, and large- or small-caliber vessels, as needed.

[0005] Metallic Devices: Coils are one of the most frequently applied embolic devices. They consist of a spiral of different materials, such as stainless steel, platinum, their alloys, or other materials, and may be coated with synthetic materials to promote clotting. One of the main concerns with coils is their proximal occlusion. When coils are used in hemorrhagic conditions, if there is an existing distal vascular network, proximal occlusion can prevent access to the bleeding site. It is important to specify the coil size because undersized coils may migrate, and oversized coils may stretch and therefore not adequately occlude the vessel. Furthermore, coils are prone to dislodging, which can lead to non-target embolization.

[0006] The Amprazer® Vascular Plug (AVP, AGA Medical, Golden Valley, MN, USA) is a braided nitinol device that can be used to achieve permanent vascular occlusion. It is a type of embolic plug. Its main advantage is that it can be recaptured and repositioned. This reduces the risk of mispositioning or migration and allows for accurate placement. If the size is incorrect, the plug can be removed and replaced. However, one major drawback of all such plugs is their reliance on effective coagulation in patients with severe coagulopathy. In addition, occlusion time can be unpredictable in situations with large vessel size and high flow rates. Although the plug can be safely, quickly, and easily deployed, it cannot secure distal small-vessel embolization distal to the deployed intravascular plug. It cannot induce distal small-vessel ischemia.

[0007] Coils and vaso-occlusive plugs are not suitable for use alone when ischemia or necrosis is required because they are unable to embolize small distal vessels.

[0008] Liquid embolic agents are gaining popularity due to their rapid application, low radiation dose, and ability to occlude small distal vessels, which allows for superior induction of ischemia and necrosis. Onyx® is a non-adherent liquid embolic material consisting of three main components: ethylene and vinyl alcohol copolymer (EVOH) for occlusion, dimethyl sulfoxide (DMSO) as a solubilizing agent, and tantalum powder for radiopaque visualization. Meanwhile, N-butyl cyanoacrylate (NBCA) is a fast-acting embolic agent, potentially reducing radiation exposure during intervention. One major drawback is the potential for backflow due to hasty injection or inadequate injection volume, which can result in non-target embolization. Migration of solidified material can also occur during catheter retraction, as material attached to the catheter tip detaches. Other causes of migration include premature polymerization and a poor correlation between polymerization rate and blood flow in high-flow vessels.

[0009] Small particle embedding agents: Polyvinyl alcohol (PVA) is a synthetic, non-resorbable embolic agent for permanent vascular occlusion. Acrylic microspheres (triscryl gelatin) are non-resorbable microspheres with precisely calibrated particle size and uniform shape. Their smooth surface structure prevents particle aggregation and allows for better penetration of the particles into distal arteries. Both of these agents are effective at inducing distal tissue necrosis, but they depend on the direction of blood flow to enable safe embolization and are prone to backflow if the flow rate slows within the administered vessel.

[0010] Current vascular occlusion plugs and coils do not allow for distal catheter placement for further embolization. An increasing number of clinical scenarios are being recognized in which distal small-vessel embolization down to the level of the capillary bed is required. These include hepatic and portal vein embolization (used to induce hypertrophy of the contralateral liver lobe before surgery), embolization of bleeding varices due to portal hypertension (where the entire length of the varix must be occluded, rather than occluding the capillary bed), transarterial chemoembolization, and prostatic artery embolization. When liquids or small particles are used for embolization and induce ischemia, there is a risk of non-target embolization and severe patient complications. Furthermore, when particles (e.g., yttrium-90) releasing concentrated drugs or radiotherapy need to be administered intravascularly for locoregional therapy, the risk of reflux or non-target embolization can mean that suboptimal doses are delivered.

[0011] In some situations, liquids or small particles cannot be safely used. For example, when hepatic vein embolization is being performed, distal vein embolization is essential to prevent the development of veno-venous collaterals, which could render the procedure ineffective. However, liquids or small particles cannot be safely injected using a catheter inserted into the hepatic vein from the jugular or femoral vein because these agents immediately follow the direction of blood flow from the liver to the heart and lungs.

[0012] Occlusion balloon catheters are used to temporarily occlude hepatic veins, allowing the injection of liquids or small particles through their central lumen; however, when the balloon is deflated, the liquid embolic agent may migrate into the heart. Also, the occlusion balloon may become stuck within the liquid embolic agent. Similarly, if a liquid embolic agent or small particles is used within an artery or portal vein after stasis or slow flow is achieved, there is an increased risk of the liquid embolic agent, small particles, or drug backflowing into another vessel, resulting in non-target embolization / treatment.

[0013] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved occlusion device that addresses the above-mentioned problems. Summary of the Invention

[0014] In accordance with the present invention, there is provided an intravascular occlusion device comprising a deformable sleeve displaceable between a contracted state and an expanded state, and a conical array of cantilevered arms extending from a distal end of the sleeve and converging toward a distal tip to define a first hemostatic valve about the distal end of the sleeve.

[0015] Preferably, the resilience of the cantilever arm array acts to bias the first hemostatic valve in a closed state.

[0016] Preferably, the cantilever arm array is sufficiently elastically deformable to allow the tips to be radially separated to facilitate passage of a surgical instrument.

[0017] Preferably, the cantilever arm array is sufficiently elastically deformable to exert a radial compressive force on a surgical instrument protruding through the first hemostatic valve that is sufficient to maintain hemostasis between the instrument and the first hemostatic valve.

[0018] Preferably, one or more of the cantilevered arms have a varying cross-sectional area along the length of the cantilevered arm.

[0019] Preferably, one or more of the cantilevered arms include a live hinge.

[0020] Preferably, the distal tips of the cantilevered arms are configured to cooperate with one another to establish a hemostatic seal at the distal tips.

[0021] Preferably, one or more of the distal tips are longitudinally offset relative to one or more other distal tips.

[0022] Preferably, one or more of the cantilevered arms include a radially inwardly extending portion located proximal to the distal tip of the respective cantilevered arm.

[0023] Preferably, the occlusion device includes an annular support connecting the sleeve and the cantilever arms, said annular support having a proximal side fixed to the distal end of the sleeve and a distal side from which the conical array of cantilever arms extends.

[0024] Preferably, the annular support is configured to substantially isolate or decouple the cantilever arm from deformation or displacement of the sleeve.

[0025] Preferably, the occlusion device comprises an array of elastically deformable spokes connected between the distal end of the sleeve and the proximal side of the annular support.

[0026] Preferably, the annular support is substantially resistant to radial deformation.

[0027] Preferably, the annular support defines a flexible region around the connection to the one or more cantilevered arms and / or the one or more deformable spokes.

[0028] Preferably, the proximal and / or distal sides of the annular support include scalloped edges.

[0029] Preferably, the sleeve includes a plurality of interconnected annular sinusoidal ribs defining a braided cylindrical sidewall.

[0030] Preferably, the cylindrical sidewall includes a plurality of radially outwardly extending projections.

[0031] Preferably, the occlusion device comprises a remotely operable actuator arranged to effect displacement of the sleeve between the expanded and contracted states.

[0032] Preferably, the occlusion device includes a membrane surrounding the cantilevered arm and at least a portion of the distal end of the sleeve.

[0033] Preferably, the membrane surrounds the distal tip of at least one of the cantilevered arms.

[0034] Preferably, the membrane is dimensioned to accommodate the relative displacement between at least two adjacent cantilevered arms.

[0035] Preferably, the occlusion device includes one or more elements provided at the proximal end of the sleeve and configured to facilitate recapture of the occlusion device.

[0036] Preferably, the occlusion device includes a second hemostatic valve about the proximal end of the sleeve.

[0037] Preferably, the second hemostatic valve comprises a conical array of cantilevered arms extending from the proximal end of the sleeve and converging towards a distal end to define the second hemostatic valve.

[0038] Preferably, the first hemostatic valve and / or the second hemostatic valve are operable to maintain bidirectional hemostasis regardless of the original direction of flow through the body cavity in which the occlusion device is to be placed.

[0039] According to a further aspect of the present invention, a method for delivering a therapeutic agent into a lumen of an intravascular system includes placing an occlusion device in a contracted state within a lumen, the occlusion device including a deformable sleeve and a conical array of cantilever arms extending from a distal end of the sleeve and converging toward a distal tip; expanding the sleeve to anchor the occlusion device within the lumen so that the cantilever arms define a first hemostatic valve; and passing a surgical instrument through the array of arms to deliver the therapeutic agent distal to the occlusion device.

[0040] Preferably, the method includes deforming the tips of at least some of the cantilevered arms radially outwardly under pressure applied by a surgical instrument to facilitate passage of the surgical instrument.

[0041] Preferably, the method includes biasing at least some of the cantilevered arms against an exterior of the surgical instrument to maintain hemostasis between the surgical instrument and the first hemostasis valve.

[0042] Preferably, the method includes providing an annular support in the occlusion device between the first hemostatic valve and the sleeve, thereby at least partially isolating the hemostatic valve from deformation or displacement of the sleeve.

[0043] Preferably, the method includes passing a surgical instrument in a first axial direction through a first hemostatic valve while maintaining hemostasis between the surgical instrument and the first hemostatic valve.

[0044] Preferably, the method includes passing a surgical instrument in a second axial direction through the first hemostatic valve while maintaining hemostasis between the surgical instrument and the first hemostatic valve.

[0045] Preferably, the method includes withdrawing the surgical instrument through the hemostatic valve and closing the hemostatic valve by elastic radial inward deformation of the array of cantilever arms.

[0046] Preferably, the method includes washing the therapeutic agent from the exterior of the surgical instrument while retracting the surgical instrument through the hemostatic valve.

[0047] As used herein, the term "surgical instrument" is intended to mean any tool or instrument used during placement / retrieval of an occlusion device that can pass through the central lumen of the device, including, but not limited to, conventional guidewires used to deliver the device to the placement site, catheters for administering embolic agents or the like distal to the device during placement, and the like.

[0048] The term "annular" as used herein is intended to mean any generally circular or ring-like element that may be cylindrical or conical in shape, may have solid or open sidewalls, and may have varying levels of rigidity.

[0049] The terms "axial" and "radial" as used herein are intended to refer to a substantially cylindrical sleeve of an occlusion device having a longitudinal direction along which the "axial" extends and perpendicular to which the "radial" extends.

[0050] The present invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0051] [Figure 1] 1 shows a side view of an intravascular occlusion device according to an embodiment of the present invention. [Figure 1a] A schematic diagram of the intravascular occlusion device shown in Figure 1 is shown to illustrate the possible angle variations at different portions of the device. [Figure 2] 2 shows a side view of the distal end of the occlusion device of FIG. 1. [Figure 3] FIG. 3 shows a perspective view of the distal end shown in FIG. 2. [Figure 4] FIG. 4 shows a perspective view of the occlusion device of FIGS. [Figure 5] 5 shows an alternative partial perspective view of the occlusion device of FIGS. 1-4. FIG. [Figure 6] 6 shows the occlusion device of FIGS. 1-5 in an expanded state. [Figure 7] 7 shows the occlusion device of FIG. 6 in a partially deflated state. [Figure 8] 8 shows the occlusion device of FIGS. 6 and 7 in a fully deflated state. [Figure 9] 1-8 depict the occlusive device, showing the membrane-forming portion of the device. [Figure 10] 10 illustrates the occlusion device of FIG. 9 with the distal end open to permit passage of a surgical instrument therethrough. [Figure 11] 11 illustrates the configuration of FIG. 10 showing a surgical instrument passing through the occlusion device. [Figure 12] 1 shows an annular support forming part of an occlusion device. [Figure 13] 13 shows an alternative form of the annular support shown in FIG. 12. [Figure 14]13 illustrates yet another alternative form of the annular support shown in FIG. 12. [Figure 15] 3 illustrates an alternative configuration of the distal end shown in FIG. 2. [Figure 16] 3 illustrates yet another alternative configuration of the distal end shown in FIG. 2. [Figure 17] 3 illustrates yet another alternative configuration of the distal end shown in FIG. 2. [Figure 18] 3 illustrates an additional alternative configuration of the distal end shown in FIG. 2. [Figure 19] 3 shows a perspective view of yet another alternative configuration of the distal end shown in FIG. 2. [Figure 20] FIG. 20 is a front view of the distal end shown in FIG. 19. [Figure 21] 1-11 shows the occlusion device of FIGS. 1-11 with a second hemostatic valve around the proximal end of the occlusion device. [Figure 22] 1 shows a side view of an intravascular occlusion device according to a second embodiment of the present invention. [Figure 23] 10 shows a side view of an intravascular occlusion device according to a third embodiment of the present invention. [Figure 24] FIG. 10 shows a side view of an intravascular occlusion device according to a fourth embodiment of the present invention. [Figure 25] FIG. 10 shows a side view of an intravascular occlusion device according to a fifth embodiment of the present invention. [Figure 26] FIG. 10 shows a side view of an intravascular occlusion device according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0052] 1-11 of the accompanying drawings, there is shown an intravascular occlusion device according to one embodiment of the present invention, generally designated 10, for use in occluding the lumen of an intravascular system to treat vascular malformations, bleeding vessels, or to occlude blood vessels to induce tissue ischemia or necrosis. As will be explained in detail hereinafter, occlusion device 10 functions to block blood flow from the distal portion of device 10 to the proximal side, and vice versa, before, during, and after delivery of an embolic or other therapeutic substance at the distal side of device 10. Occlusion device 10 also induces coagulation.

[0053] Occlusion device 10 includes sleeve 12, which preferably has an axially symmetric cross-section, is more preferably cylindrical, and is most preferably a mesh-like structure. As described in detail hereinafter, sleeve 12 is displaceable between an expanded state, as shown in FIG. 1, and a contracted state, as shown in FIG. 8, and is thus similar in structure and operation to a vascular stent. In the expanded state, sleeve 12 is radially sized to engage and retain against the interior of a vessel wall (not shown) in which intravascular device 10 is to be deployed, and may have an expanded diameter, for example, ranging from 4 mm to 20 mm. In the expanded state, sleeve 12 defines an interior lumen that provides functionality to occlusion device 10, as described below, particularly allowing for the passage of a guidewire through occlusion device 10 to facilitate deployment and a catheter for delivering embolic material distal to occlusion device 10. In the contracted state, sleeve 12 has a significantly reduced radial dimension to allow delivery to the deployment site and / or to allow for repositioning or removal of device 10.

[0054] The occlusion device 10 further includes an annular support 14 connected to the distal end via an array of spokes 16 axially spaced from the distal side or end of the sleeve 12 and connected to the distal end via a shoulder or transition zone between the sleeve 12 and the annular support 14. The annular support 14 and the sleeve 12 are preferably, but not necessarily, coaxially arranged. Unlike the sleeve 12, the annular support 14 is preferably substantially resistant to radial deformation, but may have controlled flexibility as described below. The annular support 14 has a substantially reduced diameter relative to the expanded sleeve 12 and, in exemplary embodiments, may have an inner diameter ranging from 0.5 mm to 4 mm. The annular support 14 may have an outer diameter that approximately corresponds to the outer diameter of the sleeve 12 when in a contracted state, as shown, for example, in FIG. 8.

[0055] The occlusion device 10 further comprises a first hemostatic valve 18 defined by a conical array of cantilever arms 20 extending from the distal end of the annular support 14 and converging and terminating at distal tips 22. The cantilever arms 20 are elastically deformable or otherwise displaceable to allow passage of a surgical instrument, such as a catheter or guidewire, therebetween, and in particular, allow the tips 22 to be reversibly separated from one another by elastic outward deformation of the arms 20. In a preferred arrangement, the cantilever arms 20 are elastically deformable and / or are provided with a flexible or elastically deformable connection to the annular support 14. However, it will be understood that any other mechanism may be used to achieve this function, for example, one or more hinges or the like may be provided on or about one or more of the cantilever arms 20. Additionally, as described herein below, the geometry of the arms 20 and tip 22 can be varied to modify the operation of the hemostatic valve 18, for example, by tapering the arms 20 to define a sharp tip 22 that effectively fully converges to create a hemostatic seal, or the tip 22 may be rounded or otherwise contoured to reduce friction with a passing surgical instrument, such as a guidewire or catheter.

[0056] Occlusion device 10 is illustrated schematically in FIG. 1a, highlighting the angular inclination alpha (α) of the transition zone defined by spokes 16 relative to the longitudinal axis, the angular inclination beta (β) of annular support 14, and the angular inclination gamma (γ) of arms 22. Each of these angles can vary between 0 and 90 degrees; for example, angle β is zero degrees in FIG. 1 and greater than zero degrees in FIG. 1a. The angles selected relate to the mechanical performance of various portions of occlusion device 10 and allow for fine tuning to achieve desired performance characteristics.

[0057] In the illustrated first embodiment, the sleeve 12 is formed from a biocompatible, self-expanding material, such as Nitinol, and may be at least partially covered with a polymeric, fluid-impermeable membrane 24, such as polytetrafluoroethylene (PTFE), a woven fabric (such as Dacron), or other elastomeric material (such as silicone, polyurethane, or copolymers thereof), as shown in FIGS. 9-11 . The membrane 24 is positioned to cover at least the distal end of the sleeve 12 and extend over the spokes 16 and hemostatic valve 18 to provide a seal that prevents fluid flow through the occlusion device 10 in either direction. The sleeve 12 is defined by a plurality of axially adjacent, interconnected annular rings 26, each including sinusoidal or undulating elements that facilitate transition of the sleeve 12 between expanded and contracted states through relative articulation and / or flexion of adjacent sections, providing a concertina-type action. The number of rings 26 may be varied as needed, for example, to vary the overall length of the sleeve 12. In the illustrated embodiment, each ring 26 defines 16 picks and troughs, with adjacent rings 26 secured to one another via a plurality of struts 28 extending between aligned picks on adjacent rings 26. In this embodiment, this arrangement creates an open-cell configuration, such that every two cells create a closed cell. The open-cell design promotes luminal thickening and allows the vascular endothelium to protrude through the sleeve 12. This configuration allows tissue to protrude between gaps in the sleeve 12, thus providing an anti-migration anchor feature that prevents unintended migration of the occlusion device 10 after deployment. In an exemplary, but non-limiting, embodiment, the defining elements of the rings 26 have a width of 50-400 μm and a thickness of 50-400 μm.

[0058] The sleeve 12 may be crimped onto a delivery system (not shown) prior to delivery and placement within the target vessel. In the neutral position, upon exiting the delivery system, the sleeve 12 expands to a desired size (e.g., 4 mm to 20 mm). Once placed within the vessel, the outer diameter of the sleeve 12 decreases from its heat-set diameter to a reduced diameter due to radial resistance exerted by the vessel wall, and as a result of the elasticity of the sleeve 12, it tends to exert a chronic outward force against said wall, e.g., to prevent migration. The polymer membrane 24 is left and positioned so as not to interfere with this mechanical action, e.g., by not covering the entire length of the sleeve 12.

[0059] It will be appreciated that the number, size, and exact geometry of the rings 26 may be varied as needed. For example, one or more picks may be raised from the cylindrical surface of the sleeve 12 to provide additional anchoring within the vessel. Additionally or alternatively, the cross-sectional shape of the sleeve 12 may be varied to reduce the effective radius of curvature at one or more locations on the surface of the sleeve 12 to enhance stress concentration and anchoring at the vessel wall. As a further variation, alternate rings 26 may be heat-set with different diameters to enhance stress concentration and anchoring upon deployment of the occlusion device 10.

[0060] The spokes 16 provide a transition between the relatively large diameter, flexible sleeve 12 (in the deployed or expanded state) and the relatively rigid or incompressible annular support 14 . The occlusion device 10 preferably includes four to eight spokes 16, which may have a width between 50 and 400 μm and a thickness between 50 and 400 μm, and which are covered by a membrane 24. The spokes 16 may have a different cross-sectional shape than the ring 26, and their geometry may be selected to at least partially isolate the displacement of the sleeve 12 from the rest of the occlusion device 10, particularly the annular support 14 and the hemostatic valve 18.

[0061] The spokes 16 may be formed from the same biocompatible material as the rings 26 of the sleeve 12 and, in the illustrated embodiment, have a radially sinusoidal shape. This shape facilitates controlled deformation of the spokes 16 during transition of the sleeve 12 between its expanded and contracted states, again minimizing the transmission of any deformation or movement of the sleeve 12 to the remainder of the occlusion device 10 during use. The sinusoidal shape of the spokes 16 keeps the annular support 14 and hemostatic valve 18 centered within the vessel, preventing rotation, deformation, or bending of the device, regardless of vessel diameter. This is a key aspect of the operation of the occlusion device 10, axially aligning the central lumen of the annular support 14 and the hemostatic valve 18 to allow a vascular catheter to pass through the central lumen of the occlusion device 10.

[0062] It will be understood, of course, that the number and configuration of the spokes 16 may be varied. The spokes 16 may be shaped to define an axial curve, for example, so that the end of a spoke 18 connected to the sleeve 12 may be axially offset from the opposing end of the spoke 18 connected to the annular support 14. Such a shape may provide flexibility for rotational displacement of the sleeve 12 and further isolate that rotational displacement from the annular support 14 and hemostasis valve 18. Several radial elements or spars (not shown) connected between two or more adjacent spokes 16 may be provided. These provide additional rotational stability during use. Additionally or alternatively, one or more spokes 16 and / or connecting struts (not shown) may have a wave-like shape similar to the ring 26 to facilitate bending and thereby absorb strain transmitted from the sleeve 12.

[0063] With particular reference to FIGS. 12-14 , the annular support 14 is shown in isolation in several alternative configurations. The annular support 14 serves two primary functions: first, as previously described, to isolate movement or distortion of the sleeve 12 from the hemostatic valve 18. Second, it provides a stable platform or base from which the cantilevered arms 20 of the hemostatic valve 18 extend and are displaceable to accommodate the passage of surgical instruments while providing a hemostatic seal at the distal end of the occlusion device 10. As noted above, the annular support 14 is preferably, but not necessarily, resistant to radial compression to resist deformation transmitted from the sleeve 12 during use, thereby providing a stable platform for the cantilevered arms 20 and thus ensuring consistent operation during use of the occlusion device 10. The annular support 14 can define a substantially solid sidewall, as shown in FIGS. 12 and 13 , but may also be cellular or reticulated, as shown, for example, in FIG. 14 . The annular support 14 provides a low level of compressibility or crimpability, allowing it to undergo expansion during deployment. However, it is also contemplated that the occlusion device 10 may be configured without the annular support 14, whereby the array of cantilever arms 20 extends directly from the spokes 16, although such an arrangement would not provide the above-described isolation of the hemostatic valve 18 from the sleeve 12.

[0064] Referring to FIG. 12 , the annular support 14 may be provided with holes 30 adjacent its proximal end where the spokes 16 connect. These holes 30 provide a localized increased level of flexibility, thereby reducing stress concentrations in those areas and effectively acting as hinges between the spokes 18 and the annular support 14. Corresponding holes 30 are provided adjacent the distal end to provide the same function for the cantilever arms 20. The annular support 14 also preferably has glenoid or zigzag proximal and distal edges. The spokes 16 and cantilever arms 20 are connected to respective valleys of the respective zigzag edges, which serves to shorten the overall length of the occlusion device 10. The shaped edges further provide flexibility and protection from looping / rotational forces potentially transmitted by the spokes 16 and / or cantilever arms 20. The valleys or troughs of the distal edge are preferably offset or out of phase with those of the proximal edge. This serves to further avoid the transmission of displacement or strain between the spokes 16 and arms 20, again further stabilizing the occlusion device 10 to ensure consistent performance during use. In the arrangement of FIG. 14, the holes 30 are configured to define a lattice or open frame type arrangement of the annular supports 14. Of course, more or fewer annular rows of the framework may be used to achieve desired mechanical properties and vary the overall or local flexibility of the support 14.

[0065] Extending distally from the annular support 14 is a hemostatic valve 18, preferably comprised of four to eight cantilever arms 20. In an exemplary embodiment, the cantilever arms 20 have a width (circumferential dimension) between 50 and 400 μm and a thickness (radial dimension) between 50 and 400 μm. The cantilever arms 20 are preferably disposed at an angle between 20 and 60 degrees relative to the central or longitudinal axis of the occlusion device 10. The cantilever arms 20 are preferably formed from a biocompatible, elastically deformable material and may be formed from the same material as the sleeve 12 and / or spokes 18. The cantilever arms 20 are configured to converge at their distal tips 22, particularly to provide closed ends that establish a hemostatic seal when the valve 18 is encased by the membrane 24. However, because the cantilever arms 20 are elastically deformable, the tips 22 can be spaced apart to provide a cannulation / penetration lumen that allows for the passage of surgical instruments through the hemostatic valve 18. Additionally, when a guidewire G (see FIG. 11 ) or vascular catheter is pushed through the lumen of the occlusion device 10, the cantilever arms 20 deform, opening the hemostatic valve 18 and allowing the guidewire G or catheter to pass through the lumen to access the distal side of the occlusion device 10 within the blood vessel in which the device 10 is placed. The tips 22 of the cantilever arms 20 may be shaped or otherwise configured to reduce friction with the guidewire / catheter so that the cantilever arms 20 can be easily opened during guidewire / catheter introduction. The membrane 24, particularly between adjacent cantilever arms 20, is dimensioned to enable this relative movement during opening and closing of the hemostatic valve 18, thus ensuring that a sheet is established around the guidewire or catheter to prevent fluid leakage across the occlusion device 10.

[0066] The cantilever arms 20 can be configured to adjust their flexibility and movement during use. For example, the cross-section of the cantilever arms 20 is preferably square or rectangular at the connection to the annular support 14, then tapers in thickness toward the distal tip 22. The tapered cross-section provides sufficient space for the cantilever arms 20 to converge at the apex that defines the distal-most portion of the occlusion device 10. Such a configuration establishes a hemostatic seal. The shape of the cantilever arms 20 and / or tips 22 may be modified to serve a specific function. For example, the cross-section of the cantilever arms 20 is tapered with a sharp distal tip 22, although in an alternative configuration, the distal tip 22 has a rounded taper to reduce friction between the tip 22 and the guidewire / catheter. The aspect ratio of the cantilever arms 20 is preferably selected to minimize the risk of off-axis bending during displacement of the cantilever arms 20, which could compromise the function and symmetry of the hemostatic valve 18.

[0067] Referring to FIG. 15 , the cantilever arms 20 may be provided with notches 32 or equivalent localized thickness reductions to define live hinges or regions of increased flexibility that allow the cantilever arms 20 to deform radially outward to facilitate passage of a guidewire / catheter. FIG. 16 illustrates a modification to the cantilever arms 20 to provide radially inwardly extending abutments 34 that are contacted by an advancing guidewire / catheter to urge the cantilever arms 20 radially outward. A similar function may be achieved by providing the cantilever arms 20 with a radially curved or arcuate shape that causes the cantilever arms 20 to converge toward each other along a curved path. As the guidewire / catheter passes through the hemostatic valve 18, it initially engages the curved or converging portions, opening the hemostatic valve 18 and eliminating engagement between the distal tip 22 and the guidewire / catheter. This avoids potential damage to the guidewire / catheter and prevents the cantilever arms 20 from bending inward, which could occur as a result of excessive friction between them when the guidewire / catheter is withdrawn. A similar arrangement is shown in FIG. 17, but the cantilever arms 20 are not curved but rather define a converging / diverging configuration. FIG. 18 shows a cantilever arm 20 in which the distal tip 22 is sharpened to a narrow point to ensure complete convergence. In FIGS. 19 and 20, two opposing pairs of cantilever arms 20 are connected to each other by respective flexible couplings 20a located between the annular support 14 and the distal tip 22, or at the distal tip 22, thereby retuning the mechanical performance of the cantilever arms 20. It will be understood that a greater or lesser number of cantilever arms 20 may be secured together in this manner.

[0068] The hemostatic valve 18 may also be configured such that every two cantilever arms 20 are shorter in length and / or directed further radially inward, so that the membrane 24 between each of two adjacent longer cantilever arms 20 folds inward at the distal portion to achieve a complete seal at the distal tip 22.

[0069] A section of fabric material such as Dacron or other polymer / fabric can be attached to the distal tip 22 of the cantilever arm 20 to act not only as a pro-thrombogenic fiber but also as a wiper seal or brush when the embolic injection catheter is withdrawn, thereby cleaning embolic fluid or other liquids / particles from the exterior surface of the injection catheter. This can protect against inadvertent backflow of adhesive or other material proximally as the catheter is returned through the lumen / channel of the occlusion device 10. The above modifications may be combined in various permutations and combinations with any of the embodiments disclosed herein to achieve desired performance or usage characteristics.

[0070] 21 , occlusion device 10 is shown with a second hemostatic valve 40 of the same configuration and operation as first hemostatic valve 18, but located at the opposite end of sleeve 12, i.e., proximal to occlusion device 10. This location provides an additional level of hemostatic sealing and facilitates recapture of occlusion device 10 after initial deployment from a delivery sheath or system (not shown) if the operator deems the deployment location suboptimal. A similar tapered geometry can also be used to facilitate recapture of the device without incorporating a second hemostatic valve 40.

[0071] 22 shows an endovascular occlusion device according to a second embodiment of the present invention, generally designated 100, used to occlude a lumen of an endovascular system to treat vascular malformations, bleeding vessels, or to occlude a blood vessel to induce tissue ischemia or necrosis. In this second embodiment, like components are designated with like reference numerals and perform like functions unless otherwise noted. Occlusion device 110 also includes a retractable sleeve 112, an annular support 114, a shoulder or transition zone defined by spokes 116, and a hemostatic valve 118. The proximal end of sleeve 112, defined by one of an array of annular rings 126, flares radially outward such that ring 26 forms a circular array of projections that can be deployed to engage the wall of a vessel into which device 110 is mated during use, providing additional anchoring to hold device 110 in place.

[0072] FIG. 23 illustrates a third embodiment of an occlusion device in accordance with the present invention, generally designated 210. In this third embodiment, like components are labeled with like reference numerals and perform like functions unless otherwise noted. Occlusion device 210 also includes a flared proximal end defined by one of an array of annular rings 226, forming a circular array of protrusions that, in use, engage the wall of the vessel in which device 210 is deployed to provide additional anchoring. Each of the protrusions, shown enlarged on the left side of FIG. 23, defines an opening 226a that may incorporate a radiopaque marker to enable imaging of the proximal end of occlusion device 210 during deployment or subsequent procedures. Similarly, one or more of cantilever arms 220 may define an opening 220a, which may also incorporate a radiopaque marker to enable imaging of the distal end of device 210, shown enlarged on the right side of FIG. 23.

[0073] FIG. 24 illustrates a fourth embodiment of an occlusion device in accordance with the present invention, generally designated 310. In this alternative embodiment, like components are labeled with like reference numerals and perform like functions unless otherwise noted. The occlusion device includes a contractible sleeve 312, an annular support 314, a transition zone or shoulder defined by spokes 316, and a hemostatic valve defined by cantilevered arms 320. Unlike the previous embodiment, the annular support 314 is positively inclined relative to the longitudinal axis, such as having a positive angle beta, as detailed above with reference to FIG. 1a. The annular support 314 is also a simple lattice or framework configuration having a simple zigzag configuration, with arms 320 extending from the picks of the zigzag while spokes 316 connect with the troughs of the zigzag. This arrangement allows for a shorter overall length of the occlusion device 310 and allows for tailoring of the isolation function of the support 314.

[0074] FIG. 25 shows a fifth embodiment of an occlusion device, generally designated 410, which is similar in structure to the fourth embodiment, but in which the spokes 416 and cantilevered arms 420 are connected to the same locations on the annular support 414, i.e., the zigzag-shaped picks of the support 414, again providing alternative adjustments to the flexibility of the components of the device 310.

[0075] 25 shows a sixth embodiment of an occlusion device, generally designated 510, similar in construction to the fourth embodiment but with a greater number of spokes 516, thus connecting to both the picks and troughs of a wave or zigzag formed annular support 514. An array of cantilevered arms 520 for hemostatic valves, one arm 520 extending from each pick of support 514.

[0076] During use, the occlusion device 10, 110, 210, 310, 410, 510 is initially provided in a contracted state, as shown in FIG. 8 , and delivered through a vascular catheter or sheath or custom delivery system (not shown), most preferably along a pre-placed guidewire G through which the occlusion device 10, 110, 210, 310, 410, 510 can be passed as described above. Upon reaching the deployment site, the occlusion device 10, 110, 210, 310, 410, 510 is displaced outward from the vascular catheter. The occlusion device 10, 110, 210, 310, 410, 510 may include a remotely operable actuator (not shown) that can be triggered to allow the sleeve to expand outward to the deployed or expanded state. In the absence of such an actuator, the sleeve will simply expand as soon as it is moved out of the vascular catheter. The occlusion device 10, 110, 210, 310, 410, 510 is then pressed against the wall of the vessel and anchored in place.

[0077] Following deployment of the occlusion device 10, 110, 210, 310, 410, 510, the relative stiffness of the annular support 14, 214, 314, 414, 514 can be utilized as a backstop by the delivery catheter / sheath (not shown) to help disengage the introducer / pusher (not shown) from the deployed occlusion device 10, 110, 210, 310, 410, 510.

[0078] At this point, the vascular catheter may be withdrawn or used to advance the injection catheter to the deployment site. The injection catheter is then advanced axially into the lumen of the occlusion device 10, 110, 210, 310, 410, 510, which then engages the inner surfaces of the cantilever arms 20, elastically deforming them radially outward as shown in Figures 10 and 11 to allow passage of the injection catheter. The elasticity of the cantilever arms 20 ensures that they remain engaged against the exterior of the injection catheter, and in combination with the surrounding membrane 24 (if provided), prevents fluid flow through the occlusion device 10, 110, 210, 310, 410, 510.

[0079] Once the tip of the injection catheter is positioned appropriately distal to the occlusion device 10, 110, 210, 310, 410, 510, a liquid embolic agent or other substance or therapeutic agent can then be injected through the catheter into the blood vessel. The injection catheter can then be removed, after which the cantilever arms 20 deform and return together, establishing a suitable seal to prevent backflow of emboli or other substances. It will be appreciated, therefore, that it is the resilience and orientation of the cantilever arms 20 that ensures hemostasis, and as a result, the occlusion device 10, 110, 210, 310, 410, 510 does not rely on blood pressure within the blood vessel to close the hemostatic valve 18, 118. As a result, the occlusion device 10, 110, 210, 310, 410, 510 provides hemostasis regardless of the direction of blood or fluid flow, whether from proximal to distal or vice versa.

[0080] Thus, the occlusion devices 10, 110, 210, 310, 410, 510 of the present invention enable immediate proximal permanent embolization combined with vascular occlusion. Repositioning and / or removal and replacement of the occlusion devices 10, 110, 210, 310, 410, 510 may also be possible after positioning before final release and deployment. Unlike current coils or vascular plugs, a catheter can then be passed through the occlusion device 10, 110, 210, 310, 410, 510 to access its distal side. This allows for safe and effective distal small vessel embolization with liquid embolic agents or small particles without the risk of backflow or proximal flow of the liquid embolic agent or small particles. Alternatively, high-dose distal drug infusion or small particle radiation therapy may be possible through the proximal occlusion vessel without the risk of backflow. The devices 10, 110, 210, 310, 410, 510 allow various embolic materials, including but not limited to, particulates, to be delivered distal to the deployed devices 110, 210, 310, 410, 510 via commercially available vascular catheters and microcatheters (not shown), independent of the delivery system (not shown) used to deploy the devices 10, 110, 210, 310, 410, 510. Such catheters and microcatheters can be manipulated and guided distal to the devices 10, 110, 210, 310, 410, 510, allowing these forms of embolic material to be delivered more distally and to a targeted location.

Claims

1. An intravascular occlusion device comprising a deformable sleeve that is displaceable between a condensed state and an expanded state, and a conical array of cantilever arms extending from the distal end of the sleeve and converging toward the distal tip, defining a first hemostatic valve around the distal end of the sleeve.

2. The intravascular occlusion device according to claim 1, wherein the elasticity of the array of cantilever arms acts to bias the first hemostatic valve into a closed state.

3. The intravascular occlusion device according to claim 1, wherein the array of cantilever arms is elastically deformable to allow the tips to be separated radially to facilitate the passage of surgical instruments.

4. The intravascular occlusion device according to claim 1, wherein the cantilever arm array is elastically deformable to exert a radial compressive force on a surgical instrument protruding through the first hemostatic valve, and is sufficient to maintain hemostasis between the instrument and the first hemostatic valve.

5. The intravascular occlusion device according to claim 1, wherein one or more of the cantilever arms have a cross-sectional area that changes along the length of the cantilever arm.

6. The intravascular occlusion device according to claim 1, wherein one or more of the cantilever arms include a live hinge.

7. The intravascular occlusion device according to claim 1, wherein the distal tip of the cantilever arm is configured to cooperate with each other to establish a hemostatic seal at the distal tip.

8. The intravascular occlusion device according to claim 1, wherein one or more distal tips are longitudinally offset from the other one or more distal tips.

9. The intravascular occlusion device according to claim 1, wherein one or more of the cantilever arms include a portion extending radially inward located proximal to the distal tip of each of the cantilever arms.

10. The intravascular occlusion device according to claim 1, comprising an annular support connecting the sleeve and the cantilever arm, wherein the annular support has a proximal side fixed to the distal end of the sleeve and a distal side from which the conical array of the cantilever arm extends.

11. The intravascular occlusion device according to claim 10, wherein the annular support is configured to substantially isolate or detach the cantilever arm from deformation or displacement of the sleeve.

12. The intravascular occlusion device according to claim 10, comprising an array of elastically deformable spokes connected between the distal end of the sleeve and the proximal side of the annular support.

13. The intravascular occlusion device according to claim 10, wherein the annular support is substantially resistant to radial deformation.

14. The intravascular occlusion device according to claim 10, wherein the annular support defines a flexible region around the connection to the one or more cantilever arms and / or the one or more deformable spokes.

15. The intravascular occlusion device according to claim 10, wherein the proximal and / or distal sides of the annular support include a wavy edge.

16. The intravascular occlusion device according to claim 1, wherein the sleeve includes a plurality of interconnected annular sinusoidal ribs defining a mesh-like cylindrical side wall.

17. The intravascular occlusion device according to claim 16, wherein the cylindrical side wall includes a plurality of radially outward-extending projections.

18. The intravascular occlusion device according to claim 1, comprising a remotely operated actuator positioned to cause displacement of the sleeve between the expanded state and the contracted state.

19. The intravascular occlusion device according to claim 1, comprising the cantilever arm and a membrane surrounding at least a portion of the distal end of the sleeve.

20. The intravascular occlusion device according to claim 19, wherein the membrane surrounds the distal tip of at least one of the cantilever arms.

21. The intravascular occlusion device according to claim 19, wherein the membrane is sized to correspond to the relative displacement between at least two adjacent cantilever arms.

22. The intravascular occlusion device according to claim 1, comprising one or more elements provided at the proximal end of the sleeve and configured to facilitate recapture of the occlusion device.

23. The intravascular occlusion device according to claim 1, comprising a second hemostatic valve around the proximal end of the sleeve.

24. The intravascular occlusion device according to claim 23, wherein the second hemostatic valve includes a conical array of cantilever arms extending from the proximal end of the sleeve and converging toward the tip to define the second hemostatic valve.

25. The intravascular occlusion device according to claim 23, wherein the first hemostatic valve and / or the second hemostatic valve are operable to maintain hemostasis regardless of the original direction of blood flow through the body cavity in which the occlusion device will be implanted.

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