EMBOLISATION SYSTEM FOR PROMOTING CLOT FORMATION
20230056089 · 2023-02-23
Inventors
Cpc classification
A61B17/12131
HUMAN NECESSITIES
A61B17/12177
HUMAN NECESSITIES
A61B17/12172
HUMAN NECESSITIES
A61B17/1215
HUMAN NECESSITIES
International classification
Abstract
An embolisation device (100) for promoting clot formation in a bodily lumen (170), comprising a stem (110) and a plurality of flexible bristles (120) extending outwardly from the stem, the bristles having a contracted delivery configuration and an expanded deployed configuration in which the bristles extend at least radially outwardly from the stem to anchor the device in the lumen. The embolisation device comprises a flow restrictor configured to restrict flow through the bodily lumen. The flow restrictor comprises: a membrane support (135) having a contracted delivery configuration and an expanded deployed configuration and comprising a self-expanding mesh extending at least radially outwardly from the stem; and an occluding membrane (130) mounted on the membrane support (135). The occlusion rate of the occluding mesh membrane is greater than that of the membrane support. The flow restrictor is attached to the stem at a first longitudinal end, the flow restrictor further comprising an open second longitudinal end. The occluding membrane is configured to restrict flow through the lumen when the device is deployed and the membrane support is in the expanded deployed configuration.
Claims
1. An embolisation device for promoting clot formation in a bodily lumen, comprising a stem and a plurality of flexible bristles extending outwardly from the stem, the bristles having a contracted delivery configuration and an expanded deployed configuration in which the bristles extend at least radially outwardly from the stem to anchor the device in the lumen, wherein the embolisation device further comprises: a flow restrictor configured to restrict flow through the bodily lumen, the flow restrictor comprising: a membrane support having a contracted delivery configuration and an expanded deployed configuration and comprising a self-expanding mesh extending at least radially outwardly from the stem; and an occluding mesh membrane mounted on the membrane support, wherein the occlusion rate of the occluding mesh membrane is greater than that of the membrane support; wherein the flow restrictor is attached to the stem at a first longitudinal end, the flow restrictor further comprising an open second longitudinal end, and wherein the occluding mesh membrane is configured to restrict flow through the lumen when the device is deployed and the membrane support is in the expanded deployed configuration.
2. An embolisation device according to claim 1, wherein the occluding mesh membrane is a metallic mesh membrane, preferably a Nitinol mesh membrane.
3. An embolisation device according to claim 1, wherein the self-expanding mesh is attached to the stem at a first longitudinal end, the self-expanding mesh further comprising a tubular section extending longitudinally along the stem, wherein the tubular section is configured to contact the bodily lumen in the expanded deployed configuration.
4. An embolisation device according to claim 1, wherein the occluding mesh membrane is mounted radially outside of the self-expanding mesh.
5. An embolisation device according to claim 1, wherein the occluding mesh membrane comprises a first network of wires having a first average diameter, and the self-expanding mesh comprises a second network of wires having a second average diameter, wherein the second average diameter is greater than the first average diameter.
6. An embolisation device according to claim 1, wherein the occluding mesh membrane comprises a plurality of pores, and wherein the number of pores per unit area of the occluding mesh membrane is greater than the number of pores per unit area of the self-expanding mesh.
7. An embolisation device according to claim 1, wherein the occluding mesh membrane comprises a plurality of pores having a lateral extent of less than 200 μm, and preferably less than 100 μm.
8. An embolisation device according to claim 1, further comprising a tubular connector receiving the stem and the membrane support to attach the membrane support to the stem.
9. An embolisation device according to claim 8, wherein the occluding mesh membrane is attached to the stem by the tubular connector.
10. An embolisation device according to claim 8, the tubular connector is a crimping connector.
11. An embolisation device according to claim 1, wherein the occluding mesh membrane is attached to the membrane support by adhesive or welding.
12. An embolisation device according to claim 1, wherein the flow restrictor is spaced apart from the plurality of bristles such that in the expanded deployed configuration the flow restrictor is free from contact with any bristles.
13. An embolisation device according to claim 12, wherein the embolisation device is configured to be delivered from a delivery catheter to the bodily lumen in a distal direction, and comprises a bristle segment positioned distally from the flow restrictor.
14. An embolisation device according to claim 1, wherein the embolisation device comprises a bristle segment and the flow restrictor is located longitudinally within the bristle segment or directly adjacent the bristle segment.
15. An embolisation device according to claim 14, wherein the embolisation device is configured to be delivered from a delivery catheter to the bodily lumen in a distal direction, the bristle segment is a proximal bristle segment and the embolisation device further comprises a distal bristle segment spaced apart in the distal direction from the proximal bristle segment.
16. A method of manufacturing an embolisation device for promoting clot formation in a bodily lumen, comprising: providing a stem; providing a plurality of flexible bristles extending outwardly from the stem, the bristles having a contracted delivery configuration and an expanded deployed configuration in which the bristles extend at least radially outwardly from the stem to anchor the device in the lumen; providing a membrane support having a contracted delivery configuration and an expanded deployed configuration and comprising a self-expanding mesh; mounting an occluding mesh membrane on the membrane support, the occluding mesh membrane having a greater occlusion rate than that of the membrane support; and attaching the membrane support to the stem such that it extends at least radially outwardly from the stem, the membrane support having a contracted delivery configuration and an expanded deployed configuration in which the radial profile of the membrane support is greater than in the contracted delivery configuration; wherein the membrane support is attached to the stem at a first longitudinal end, the membrane support further comprising an open second longitudinal end, and the occluding mesh membrane is configured to restrict flow through the lumen when the device is deployed and the membrane support is in the expanded deployed configuration.
17. The method of claim 16, wherein the steps of providing the membrane support, mounting the occluding mesh membrane on the membrane support and attaching the membrane support to the stem comprise the steps of: providing a self-expanding tubular mesh; wrapping the occluding mesh membrane around, and attaching it to, the tubular mesh; providing a tubular connector on the stem; inserting an end of the tubular mesh into the tubular connector; and crimping the connector.
18. The method of claim 17, wherein the occluding mesh membrane is wrapped around and attached to the tubular mesh before the tubular mesh is connected to the stem by the crimping connector.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] To enable a better understanding of the present disclosure, and to show how the same may be carried into effect, reference will now be made, by way of example only, to the accompanying schematic drawings, in which:
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
DETAILED DESCRIPTION
[0030] Throughout this disclosure the term ‘embolisation device’ may refer to a device which may be permanently or semi-permanently implanted in a bodily lumen. Accordingly, the ‘embolisation device’ may be configured to be disposed within the bodily lumen for a period of time, such as a number of days, or disposed in the lumen indefinitely. To this end, the ‘embolisation device’ may be configured to be selectively detached from a delivery element so that it may be implanted in the bodily lumen in isolation.
[0031] Throughout this disclosure the term ‘bodily lumen’ may refer to the inside space within a tubular structure of the human or animal body. The ‘bodily lumen’ may be, for example, an artery or vein.
[0032] Throughout this disclosure the term ‘contracted delivery configuration’ of an element may refer to a configuration of the element which has a smaller radial extent than an expanded deployed configuration of the element.
[0033] Throughout this disclosure the term ‘to anchor’ may refer to partly or fully securing an element in a position.
[0034] Throughout this disclosure, the term ‘stem’ may refer to an elongate element which extends longitudinally along the length of the embolisation device to act as a backbone for the device, and has a significantly smaller radial extent than the further elements of the embolisation device (for example, the plurality of flexible bristles). The stem may extend along substantially the whole longitudinal extent of the plurality of flexible bristles (e.g. when the embolisation device is in an unrestrained configuration, contracted delivery configuration and/or expanded deployed configuration). The stem may extend along substantially the whole length of the embolisation device.
[0035] In any of the examples described herein, the term ‘bristle’ may refer to an elongate strand of material formed substantially a single piece. The ‘bristle’ may be a resilient bristle. The resilient bristle may be biased towards a particular curvature.
[0036] Throughout this disclosure, the term ‘radially outwardly’ does not exclude the element additionally extending in the longitudinal direction of the device. For example, the plurality of flexible bristles may extend radially outwardly and longitudinally from the stem.
[0037] Through this disclosure, the term “radial profile” may refer to a radial extent in a particular direction radially outwardly from the stem of the embolisation device. For example, the embolisation device has a lower radial extent in the contracted delivery configuration than in the expanded deployed configuration.
[0038] The plurality of flexible bristles may have a contracted configuration in the contracted delivery configuration. The plurality of flexible bristles may have an expanded configuration in the expanded deployed configuration. The plurality of bristles may extend radially outwardly from the stem in a plurality of circumferential directions about the stem.
[0039] In the expanded configuration, the plurality of flexible bristles may be configured to anchor the device in the bodily lumen. The plurality of flexible bristles may be configured to provide part or substantially all of the anchoring force for the embolisation device in the bodily lumen. The membrane support may additionally be configured to provide part of the anchoring force for the embolisation device in the bodily lumen.
[0040] In the expanded configuration, the plurality of flexible bristles may be configured to contact the bodily lumen.
[0041] In the contracted delivery configuration, the plurality of flexible bristles extending outwardly from the stem are contracted such that radial extent of the device is less than the radial extent of the expanded deployed configuration of the element. In the contracted delivery configuration the device fits inside the delivery catheter.
[0042] The bristles may be made of a flexible or resiliently deformable material such as stainless steel, Elgiloy or Nitinol. Other suitable materials may also be used, such as any suitable polymer or any other shape memory metal or metal alloy. The membrane may be a metallic mesh membrane made of materials such as stainless steel or Nitinol. The membrane support may be made of any self-expanding material, such as a polymer, Nitinol or stainless steel. The stem may be made of stainless steel or other suitable material and may comprise a twisted wire from which the bristles extend and on which the flow restrictor is mounted. The stem may alternatively comprise a hollow tube wherein the walls of the hollow tube hold the radially extending bristles in place. For example, the tube may be formed from a heat shrinkable material as is well known in the art. Alternatively or additionally, the bristles may be held by the stem using other means such as adhesives.
[0043] The diameter of an individual flexible bristle may range from 0.036 mm (0.0014 inches) to 0.053 mm (0.0021 inches). For example, the diameter of an individual flexible bristle may be 0.381 mm (0.015 inches), 0.445 mm (0.0175 inches) or 0.508 mm (0.02 inches). The overall radial diameter of the expanded flexible bristles may range from 5 mm to 30 mm.
[0044] The occluding membrane may be a thin film membrane. For example, the occluding membrane may have a thickness of 4 μm to 35 μm and a radial diameter, in the deployed configuration, of 5 mm to 20 mm. For example, the diameter of the membrane may be 6.5 mm, 9 mm or 16 mm.
[0045] In the illustrated embodiments described herein, the same reference numerals are used for corresponding elements in each example.
[0046]
[0047] In some examples, the plurality of bristles 120 may all extend radially outwardly and longitudinally distally in the contracted delivery configuration, or longitudinally proximally in the contracted delivery configuration, or combination of the two. In the illustrated example, the plurality of bristles 120 are divided into a proximal bristle segment 120a and a distal bristle segment 120b. The bristles of the proximal bristle segment 120a extend radially outwardly and longitudinally proximally in the contracted delivery configuration, whereas the bristles of the distal bristle segment 120b extend radially outwardly and longitudinally distally in the contracted delivery configuration. Such a configuration effectively anchors the device to the bodily lumen once deployed.
[0048] In the illustrated example, the flow restrictor is situated adjacent to the distal end of the proximal bristle segment 120a, whereas in other examples it may be situated elsewhere, such as, for example, longitudinally within one of the bristle segments, adjacent to the proximal end of the proximal bristle segment 120a or adjacent to the proximal or distal ends of the distal bristle segment 120b.
[0049] The occluding membrane has greater occluding properties than the membrane support. In other words, the occluding membrane causes a greater rate of occlusion in the vessel than the membrane support. Due to the presence of the membrane support, the occluding rate of the occluding membrane may be selected to be high without compromising on the required structural strength of the flow restrictor, as this structural strength is provided by the membrane support.
[0050] The occluding membrane may be a mesh membrane. The use of a mesh membrane provides a structure for cell attachment an growth and thus increase occlusion of the device. Reducing the mesh pattern size (i.e. increasing the number of pores per unit area) increases the blood contact surface area to facilitate increased occlusion rates. This is especially true of micro-mesh patterns that can be achieved by using thin film membranes (i.e. membranes having a thin film thickness).
[0051] Some devices may use a polymer membrane. Polymer membranes are prone to tearing during manufacturing or movement of the device between the contracted delivery configuration and the expanded deployed configuration, reducing the effectiveness of the device, especially when recaptured and redeployed. Some devices may have the membrane positioned adjacent a bristle segment or longitudinally within a bristle segment. The neighbouring bristles will guide the membrane passively between the contracted delivery configuration and the expanded deployed configuration. However, especially for thin film membranes, the passive force of the neighbouring bristles may not reliably move the thin film membrane between the contracted delivery configuration and the expanded deployed configuration (i.e. may not provide adequate support to the membrane to fold and unfold the membrane in a reliable manner, which may in turn affect occlusion of the device).
[0052] The embolisation device is guided through the delivery catheter 160 using the delivery element 140. The delivery element 140 is connected to a proximal end of the embolisation device 100 via a releasable connecting mechanism 150.
[0053] Once the embolisation device has been delivered to the target site within the bodily lumen 170, then the embolisation device is moved distally relative to the delivery catheter 160 such that the bristles 120 expand to the expanded deployed configuration and engage the walls of the bodily lumen 170 to anchor the device to the lumen 170. This configuration is shown in
[0054] If it is determined that the embolisation device is incorrectly placed within the bodily lumen 170, then it may be recaptured by the delivery catheter 160 and redeployed at a new position within the bodily lumen 170. Once it is determined that the final placement of the embolisation device 100 is correct, the embolisation device 100 is released from the delivery element 140 and the device 100 is implanted in the bodily lumen 170. This is shown in
[0055]
[0056] In the example shown in
[0057] The occluding membrane 130 is mounted on a self-expanding membrane support 135. The occluding membrane 130 is a mesh membrane and the membrane support 135 comprises a self-expanding mesh onto which the occluding membrane is mounted. In the device 100 shown in
[0058] The flow restrictor, which comprises the occluding membrane 130 and the membrane support 135, is attached to the stem at a first longitudinal end (the left end shown in
[0059]
[0060] The membrane support 135 may be any self-expanding structure that is suitable for moving the occluding membrane 130 between the contracted delivery configuration and the expanded deployed configuration. For example, the membrane support 135 may comprise a self-expanding mesh. The mesh membrane support provides support across the surface area of the membrane 130 and ensures that the membrane 130 moves between the contracted delivery configuration and the expanded deployed configuration in a reliable manner. In the example illustrated in
[0061]
[0062] Whilst in the examples disclosed with respect to
[0063]
[0064] As in the examples shown in
[0065] In yet further examples, the occluding membrane 130 shown in
[0066] The various embolisation devices 100 according to the present disclosure can be manufactured by the following method: [0067] providing a stem; [0068] providing a plurality of flexible bristles extending outwardly from the stem, the bristles having a contracted delivery configuration and an expanded deployed configuration in which the bristles extend at least radially outwardly from the stem to anchor the device in the lumen; [0069] providing a self-expanding membrane support; [0070] mounting an occluding membrane on the membrane support; and [0071] attaching the membrane support to the stem such that it extends at least radially outwardly from the stem, the membrane support having a contracted delivery configuration and an expanded deployed configuration in which the radial profile of the structure is greater than in the contracted delivery configuration; [0072] wherein the occluding membrane is configured to restrict flow through the lumen when the device is deployed and the membrane support is in the expanded deployed configuration.
[0073] It is noted that the steps of the above method are not necessarily presented in chronological order. For example, the bristles could be provided on the stem before or after the membrane support is attached to the stem. Likewise, the membrane support could be attached to the stem before or after the occluding membrane is mounted on the membrane support. Other variants will be apparent to the skilled person.
[0074] In some examples, the method may comprise the steps of: [0075] providing a self-expanding tubular mesh; [0076] wrapping the occluding membrane around, and attaching it to, the tubular self-expanding mesh; [0077] providing a tubular connector on the stem; [0078] inserting an end of the tubular mesh into the tubular connector; and [0079] crimping the connector.
[0080] It is again noted that the steps are not necessarily presented in chronological order. For example, the membrane could be wrapped around and attached to the tubular mesh before or after and end of the tubular mesh is inserted into the tubular connector, and before or after the connector is crimped. Similarly, the tubular connector could be provided on the stem before or after an end of the tubular mesh is inserted into the tubular connector. Other variants will be apparent to the skilled person.
[0081] Table 1 below contains exemplary dimensions for the implant.
TABLE-US-00001 TABLE 1 Membrane Membrane thickness Diameter Bristle Diameter 4-35 microns 6.5 mm 0.381 mm (0.015″) 4-35 microns 9 mm 0.445 mm (0.0175″) 4-35 microns 16 mm 0.508 mm (0.02″)
[0082] All of the above are fully within the scope of the present disclosure, and are considered to form the basis for alternative embodiments in which one or more combinations of the above described features are applied, without limitation to the specific combination disclosed above.
[0083] In light of this, there will be many alternatives which implement the teaching of the present disclosure. It is expected that one skilled in the art will be able to modify and adapt the above disclosure to suit its own circumstances and requirements within the scope of the present disclosure, while retaining some or all technical effects of the same, either disclosed or derivable from the above, in light of his common general knowledge in this art. All such equivalents, modifications or adaptations fall within the scope of the present disclosure.