An occlusion device for preventing the passage of blood through an artery or vein

Abstract

The present invention relates to an occlusion device for use in the vascular system to prevent the passage of blood through an artery or vein. The aim of the invention is to pass an occlusion device through a smaller-caliber catheter. This objective is achieved by an occlusion device (10) for preventing the passage of blood into an artery or vein comprising a wire structure (20) and a blood-impermeable membrane (25), the wire structure having a proximal end and a distal end and comprising a proximal tip (22) and a distal tip (21) and between the tips a proximal tapered section (52), a cylindrical section (51) and a distal tapered section (50). The tips (21, 22) contain an even number of wires greater than five, and that the wires (20) extend from the tips (21, 22) in pairs along the conical sections (50, 52) and that the cylindrical section (51) is formed by wire pairs consisting of two wires (20) of the adjacent wire pairs of the conical sections (50, 52).

Description

An occlusion device for preventing the passage of blood through an artery or vein

[0001] The present invention relates to an occlusion device for use in the vasculature, preventing the passage of blood through an artery or vein.

[0002] The occlusion devices described in this disclosure are intended for the treatment of defects in arteries and veins. These defects include arteriovenous malformations, arteriovenous fistulas and end organ bleeding. Preferably, these defects would be treated with devices and techniques that leave the associated parent artery or vein intact.

[0003] The alternative, when the parent artery preservation is not advisable, is parent artery occlusion, or PAO. Parent artery occlusion is achieved by quickly and securely closing off a length of a blood vessel near the defect, and preferably results in the immediate and complete physical blockage of the blood flow to the defect. Several endovascular devices and techniques have been developed to accomplish parent artery occlusion. Detachable balloons have been previously proposed and used for parent artery occlusion, but were not successful because the balloons too often leaked and deflated leading to major embolic complications. Occlusive coils have been used to pack arteries, but this sometimes might require numerous coils and then becoming quite expensive. In addition this technique does not allow for immediate occlusion. The blood that passes the coils as the coagulation is taking place may lead to the creation and migration of thrombus from the mass of coils. Vascular plugs, such as described in US 5,725,552 and known as “Amplatzer” vascular plugs have been used to accomplish parent artery occlusion. The open braid of the these plugs may result in dislodgement of thrombus as it is forming on the plug, leading to embolization downstream of the occluded artery. These devices exist in numerous sizes for use in vessels of different diameters. The larger the device the larger the catheter size that is required to introduce the device. This can often cause problems because some vessels can only be accessed with small bore catheters.

[0004] Other devices such as the Medtronic MVP occlusion device have a stent-like structure that comes to a point at each end of the device. It is covered over theproximal side of the device with a Polytetrafluoroethylene (PTFE) film. The distal end of the device is open to allow blood to enter. The stent structure forces the film into contact with the vessel wall. Once in place, the device provides a complete physical obstruction to blood flow.

[0005] When the devices are implanted into the artery or vein there is a force generated by the blood pressure pushing against the occluded surface of the device. To prevent the migration of the occlusion device, the device is held in place in the artery by the frictional force generated by the radial force of the device against the vessel wall and the deformation caused by the device on the vessel wall.

[0006] The optimal goal for the clinician is to be able to introduce the largest device through the smallest catheter. This is because in many cases the vascular pathway that must be traversed by the introduction catheter is tortuous and relatively small. In many clinical situations the target vessel to be occluded is larger in caliber than vessels that are navigated by the introduction catheter to access the target vessel. Since larger catheters are intrinsically more rigid than the smaller catheters, they sometimes cannot pass through smaller caliber tortuous vasculature.

[0007] However this design goal creates other problems. In order for the device to pass through a smaller catheter, the structure of the device must be smaller. The smaller the device, the lower its radial force and the lower the frictional force to resist the force which tries to push the device forward. There is a need for a device that passes through a smaller catheter and occludes larger vessels without the risk of migration.

[0008] The invention achieves the goal of passing a device through a smaller caliber catheter with an occlusion device for preventing the passage of blood through an artery or vein, comprising a wire structure and a blood-impermeable membrane, wherein the wire structure has a proximal and a distal end and comprises a proximal and a distal tip and between the tips a proximal conical section, a cylindrical section and a distal conical section. The device in accordance with the invention is characterized in that the tips embrace a pair number of wires larger than 5, and in that the wires extend from the tips in pairs along the conical sections, and thecylindrical section are formed by pairs of wires consisting of two wires of adjacent wire pairs of the conical sections.

[0009] The pairs of wires of an occlusion device in accordance with the invention may be held together by suitable means at the end of the conical sections opposite to the tips and the proximal and distal ends of the cylindrical sections, respectively, in particular by gluing, welding, clamping and / or by metallic bands. Such metallic bands may preferably be made from a Platinum based alloy. The use of Platinum based alloy for the bands make them radio opaque and hence more visible under fluoroscopic imaging.

[0010] The device in accordance with the invention may in particular comprise 6 or 8 wires that form 3 or 4 pairs of wires, respectively. The pairs of wires are split at the end of the proximal conical section into single wires, and each of the single wires of such pair joins a single wire of one of the adjacent wire pairs of the conical section to form new pairs of wires in the cylindrical section. At the end of the cylindrical section, the wire pairs are split up again to form in the same way new pairs of wires in the distal conical section, consisting of wires of adjacent wire pairs of the cylindrical section.

[0011] In this way, a transitional section is formed between the conical sections and the cylindrical section, where single wires are distributed along the circumference of the device, thus doubling the number of struts in this section compared to the conical and cylindrical sections. This transitional section is located in the area where the device gets into contact with the vessel wall when it is unfolded. The number of single wires ensures that the device is safely anchored and that the membrane occluding the vessel is well maintained on the device towards the vessel walls.

[0012] The wires being maintained in pairs along the conical and cylindrical sections ensures sufficient stability of the device at the same time.

[0013] Preferably, the wires are made from super-elastic material, for example Nitinol. In particular, the material may have shape-memory properties.

[0014] In an embodiment of the device in accordance with the invention, the diameter of the cylindrical section is less than the maximum diameter of the conical section. Thus, the transitional section between the conical and the cylindrical sections engages efficiently with the vessel wall and prevents the device even better from migrating in the vessel.

[0015] Preferably, the device may comprise hooks extending in distal direction from the distal end of the cylindrical section. The hooks engage the vessel wall when the device opens and resist any forward movement of the device due to blood pressure. The device and method described provide for embolization of arteries with an embolic implant, suitable for use for PAO. The device allows for rapid occlusion of the artery and active fixation of the device in the wall of the vasculature preventing any possibility of device migration.

[0016] The hooks may in particular extend in a direction parallel to the outer surface of the cylindrical section. When the device is positioned by means of a catheter and deployed therefrom, the distal conical section and the distal side of the cylindrical section are deployed first, such that the hooks in this case extend slightly outwards, so that they engage easily with the vessel wall, so that the device is safely positioned and cannot migrate within the vessel.

[0017] When the device exits the catheter, and the distal half of the device starts to open, the elongated members on the hook bands are oriented at an oblique angle to the vessel wall. Given that the device diameter is larger than the recommend vessel diameter, the hooks will engage in the vessel wall.

[0018] The device may in addition comprise hooks located at the proximal end of the cylindrical section, extending in distal direction.

[0019] The membrane may be sealed to prevent ingress of blood in the cylindrical section of the device.

[0020] To assist in manufacture of the support structure whilst making use of the mechanical effect required of the membrane, the invention proposes another featurewhereby the intermediate portion of one of the wires forming the structure is joined at one end to the proximal portion and at the other end to the distal portion of the same wire by rounded elbows subtending at an angle ^ delta such that 90° < ^ < 135°.

[0021] Preferably, the proximal tip has connection means for a guide wire. The device may then be attached to a pushing stylet. This allows for the device to be introduced and positioned, and to be repositioned, if necessary. The device is pushed the length of the catheter and exits the catheter into the target artery. If the clinician decides that the position is not optimal, the device can be withdrawn into the catheter. In order to confirm the correct fixation of the device, the pushing stylet can be pushed forward. If the device does not move forward it is an indication to the clinician that the hooks have engaged into the vessel wall. Once the correct position has been confirmed, the device can be removed from the pushing stylet by rotating the stylet to separate the device from the stylet.

[0022] The device can be temporarily attached to the stylet by numerous techniques. One method is to have a female or male screw element attached to the proximal end of the device and a mating screw on the distal end of the delivery stylet. When the device is to be deployed definitively, the operator rotates the proximal part of the stylet unscrewing the distal end of the stylet from the proximal end of the device.

[0023] Various embodiments of the invention are described in greater detail in the following, using the attached figures:

[0024] Figure 1 is a schematic perspective view of one embodiment of the present invention;

[0025] Figure 2 is a schematic perspective view of the embodiment of figure 1 with the membrane removed;

[0026] Figure 3 is a schematic representation of the embodiment of the invention of the previous figures showing the device expanding as it exits the delivery catheter ;

[0027] Figure 4 is a schematic representation of one aspect of the embodiment of the previous figures showing a hook engaging a vessel wall ;

[0028] Figure 5 is a schematic representation of another embodiment of the invention;

[0029] Figure 6 is a schematic representation of an embodiment of the invention compressed within the delivery catheter ;

[0030] Figure 7 is a schematic representation of an aspect of the invention showing an embodiment of the hook;

[0031] Figure 8 is a schematic representation of an aspect of the invention showing another embodiment of the hook;

[0032] Figure 9 is a schematic representation of an aspect of the invention showing a further embodiment of the hook;

[0033] Figure 10 is a schematic representation of an aspect of the invention showing an embodiment of the hook when it is compressed within the delivery catheter ;

[0034] Figure 11 is a schematic representation of an aspect of an embodiment of the invention implanted in the vessel.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. As used herein, the singular form “a”, “an” and “the” are intended to include the plural forms as well as the singular forms, unless the contextclearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising” when used in this specification, specify the presence of stated features, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0036] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one having ordinary skill in the art to which this invention belongs. It will further be understood that the terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0037] In describing the invention, it will be understood that a number of techniques and steps are disclosed. Each of these has individual benefits and each can also be used in conjunction with one or more, or in some cases all, of the other disclosed techniques. Accordingly, for the sake of clarity, this description will refrain from repeating every possible combination of the individual steps in an unnecessary fashion. Nevertheless, the specification and claims should be read with the understanding that such combinations are entirely within the scope of the invention and the claims.

[0038] Figure 1 shows one embodiment an occlusion device 10 in accordance with the present invention. The occlusion device consists of a distal conical section 50, a central cylindrical section 51 and a proximal conical section 52. The occlusion device of this embodiment comprises eight wires 20 that are connected between a distal tip 21 and a proximal tip 22.

[0039] The wires extend in pairs from the proximal and distal tips 22, 21 along the conical sections 52, 50, as well as along the cylindrical section 51, wherein the pairs of wires 20 are maintained in their position by metallic bands 23.

[0040] The pairs of wires are split at the end of the conical sections towards the cylindrical section, so that new pairs are formed in the cylindrical section, that consist of two wires of two adjacent wire pairs of the conical sections. Thus, transitional sections 54 are formed between the conical sections 52, 50 and the cylindrical section 51 that consists of single wires. These sections 54 ensure an evenly distributed contact of the device with the vessel wall and anchors the device safely in the vessel.

[0041] To enhance the anchorage of the device in the vessel further, four hook elements 24 are located near the distal end of the central cylindrical zone 51.

[0042] To prevent blood passage once the device is deployed in a vessel, the metal structure of the device is covered by a thin polymeric film 25 as an impermeable membrane. The thin polymeric film 25 does not cover the distal conical zone 50 including and adjacent to the hook elements 24.

[0043] Figure 2 shows view of the present invention with the film removed.

[0044] Figure 3 shows an embodiment of the of the present invention 10 as it exits a catheter 26 with which it is delivered to the area of implantation. When the distal conical section 50 opens as the device 10 exits the distal end of the catheter 26 and the central cylindrical section 51 opens the angle of the hook elements 24 to the vessel wall 30 allowing them to engage with the vessel wall 30 for the hook elements 25.

[0045] Figure 4 shows a detail view of the hook element 24 of an embodiment of a device in accordance with the present invention 10 as the elongated element 28 of the hook element 24 engages with the vessel wall 30.

[0046] Figure 5 shows another embodiment of a device 10 in accordance with the present invention. The elements of the device 10 are the same as that shown in Figure 1, the difference are the relative positions of the twelve bands 23 and the four hook bands 24. A maximum of only two bands 23 are on any given orthogonal plane53. Additionally there are only two hook elements 24 on any given orthogonal plane 53.

[0047] In addition, the diameter of the transitional section between the conical sections and the central cylindrical section is larger than the diameter of the cylindrical section. This enables the wires of the transitional section to even better engage with the vessel wall and to support better the membrane to occlude the vessel.

[0048] Figure 6 shows a cross section cut of the plane of the bands 23 of the embodiment of the occlusion device 10 of Figure 5 when the device 10 is compressed down and inside the introduction catheter 26. For clarity the polymeric film 25 is not shown. The compressed polymeric film (not shown in this figure) would occupy the intraluminal space 34 between the wires 20 and the bands 23. Because there are only two bands 23 on a plane it is obvious that it allows for more room for the polymeric film 25 to fold down in the lumen of the introduction catheter 26.

[0049] Figure 7 shows one embodiment of the hook element 24 on the wires 20 of the device 10. The hook element 24 has an elongated member 27 extending from the hook element 24 with a bend 29.

[0050] Figure 8 shows one embodiment of the hook element 24 on the wires 20 of the invention 10. The hook element 24 has elongated member 27 extending from the hook element 24.

[0051] Figure 9 shows another embodiment of the device in accordance with the invention 10 where the hook element 24 is created by using a long band 35 that is longer and wider than the other bands 23. An additional bent hook wire 36 creates the hook element 24. The hook wire 36 can be fixed to the long band 35 and wires 20 by crimping or laser welding 37

[0052] Figure 10 shows the invention 10 compressed within a catheter 26. The bend 29 in the hook wire 36 is tangent to the inner wall 31 of the catheter 26. Thiscauses the hook tip of the hook 36 element 24 to be pushed away from the inner wall 31 of the catheter 26. This allows the occlusion device 10 to be advanced through the catheter 26 without hook tip 30 of the hook element 24 touching the inner wall 31 of the catheter 26.

[0053] Figure 11 shows an aspect of the present invention 10 implanted in a vessel 32. The wires 20 of the structure push against the vessel wall 32 deforming the vessel wall 32 slightly. The elongated member of the hook 28 enters the vessel wall 32. The wires 20 of the device 10 prevent the elongated element 28 of the hook element 24 from entering the vessel any further than the length of the elongated element 28 of the hook element 24. Once engaged the hook elements 28 should prevent the invention 10 from moving distally under the pressure of the blood flow.

Claims

CLAIMS 1. An occlusion device (10) for preventing the passage of blood through an artery or vein (30), comprising a wire structure (20) and a blood-impermeable membrane (25), the wire structure having a proximal and a distal end and comprising a proximal (22) and a distal tip (21) and between the tips a proximal conical section (52), a cylindrical section (51) and a distal conical section (50), characterized in that the tips embrace a pair number of wires larger than 5, and the wires (20) extend from the tips (21, 22) in pairs along the conical sections (50, 52), and the cylindrical section (51) is formed by pairs of wires consisting of two wires (20) of adjacent wire pairs of the conical sections (50, 52).

2. An occlusion device (10) in accordance with claim 1, characterized in that the pairs of wires (20) are held together by suitable means at the end of the conical sections (50, 52) opposite to the tips (21, 22) and the proximal and distal ends of the cylindrical section (51), respectively, in particular by gluing, welding or clamping and / or by metallic bands (23).

3. An occlusion device (10) in accordance with claim 1 or 2, characterized in that it comprises 4 wire pairs (20) in each conical (50, 52) or cylindrical section (50).

4. An occlusion device (10) in accordance with any one of claims 1 to 3, characterized in that the wires (20) have form memory.

5. An occlusion device (10) in accordance with any one of claims 1 to 4, characterized in that the diameter of the cylindrical section (51) is less than the maximum diameter of the conical section.

6. An occlusion device (10) in accordance with any one of claims 1 to 5, characterized in that the device comprises hooks (24) extending in distal direction from distal end of the cylindrical section (51).

7. An occlusion device (10) in accordance with claim 6, characterized in that the hooks (24) extend parallel to the cylindrical section (51).

8. An occlusion device (10) in accordance with any one of claims 1 to 7, characterized in that the proximal tip (22) has connection means for a guide wire.

9. An occlusion device (10) in accordance with any one of claims 1 to 8, characterized in that the membrane (25) covers at least the proximal conical section (52).

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