Patent Application
20230210545
This application claims priority to U.S. provisional patent application No. 63/295,340 filed Dec. 30, 2021 entitled “Expandable Intraluminal Device,” the disclosure of which is hereby incorporated by reference in its entirety.
This application relates generally to medical devices and methods of making and using medical devices. In particular, various embodiments of an expandable intraluminal device and a method of removing obstructions such as clots from human blood vessels are described.
Intraluminal devices such as stent retrievers are known and commonly used to remove obstructions, such as clots, from human blood vessels. A stent retriever includes an expandable mesh-like structure, which can be in a thin compact form to allow it to penetrate through a blood clot. Once incapsulated in a clot, the mesh-like structure is expanded, exerting a radial force on the clot to expand into and capture the clot inside the mesh-like structure. The clot can be removed from the vessel by retrieving the stent retriever.
Conventional stent retrievers are constructed of shape memory materials and rely on the shape memory property to expand to a certain dimension. However, relying solely on the shape memory property does not allow the user to control the radial expansion of a stent retriever which may be needed for effective penetration through a blood clot and successful removal of the clot through variably sized vessels.
Therefore, there remains a need for improved intraluminal devices to treat various medical conditions in blood vessels or other hollow body organs. It would be desirable to provide an expandable intraluminal device that allows the user to control the expansion and contraction of the device, and thus the radial force of expansion, to facilitate effective penetration and removal of an obstruction from blood vessels.
In one aspect, embodiments of the disclosure feature an intraluminal device. In general, an embodiment of the intraluminal device comprises a radially expandable body having a proximal end portion and a distal end portion and a control member operable to expand and contract the radially expandable body. The radially expandable body comprises plural sets of first filaments spiraling in a first direction from the proximal end portion to the distal end portion and plural sets of second filaments spiraling in a second direction from the proximal end portion to the distal end portion. The plural sets of first filaments intersect the plural sets of second filaments, forming plural cross sections of the radially expandable body. At least one of the plural sets of first filaments comprises a filament constructed of a radiopaque material.
In various embodiments of the aspect, each of the plural sets of first filaments comprises a filament constructed of a radiopaque material.
In various embodiments of the aspect, each of the plural sets of second filaments is free of a filament constructed of a radiopaque material.
In various embodiments of the aspect, each of the plural sets of first filaments comprises two filaments that are twisted and each of the plural sets of the second filaments comprises two filaments that are twisted.
In various embodiments of the aspect, at a cross section where one of the plural sets of first filaments and one of the plural sets of second filaments intersect, one of the two filaments of the one of plural sets of first filaments passes between the two filaments of the one of plural sets of second filaments, and one of the two filaments of the one of plural sets of second filaments passes between the two filaments of the one of plural sets of first filaments. In a specific embodiment, the plural sets of first filaments each comprises a radiopaque filament and a non-radiopaque filament, and the plural sets of second filaments each comprises two non-radiopaque filaments.
In various embodiments of the aspect, the control member comprises a pull wire having a distal end portion coupled to the distal end portion of the radially expandable body, allowing to apply an axial force to move the distal and proximal end portions of the radially expandable body relative to each other.
In another aspect, embodiments of the disclosure feature an intraluminal device. The intraluminal device comprises a radially expandable body having a proximal end portion and a distal end portion and a control member operable to expand and contract the radially expandable body. The radially expandable body comprises plural sets of first filaments spiraling in a first direction from the proximal end portion to the distal end portion, plural sets of second filaments spiraling in a second direction from the proximal end portion to the distal end portion. The plural sets of second filaments intersect the plural sets of first filaments, forming plural cross sections of the radially expandable body. The intraluminal device further comprises plural radiopaque filaments including at least a first radiopaque filament and a second radiopaque filament. The first radiopaque filament comprises a first section grouped with one of the plural sets of first filaments, and the second radiopaque filament comprises a first section grouped with one of the plural sets of second filaments. The first radiopaque filament and the second radiopaque filament are twisted at a cross section where the one of the plural sets of first filaments and the one of the plural sets of second filaments intersect, to allow a second section of the first radiopaque filament to be grouped with the one of the plural sets of second filaments and allow a second section of the second radiopaque filament to be grouped with the one of the plural sets of first filaments.
In various embodiments of the aspect, each of the plural sets of first filaments comprises two filaments that are twisted, and each of the plural sets of second filaments comprises two filaments that are twisted.
In various embodiments of the aspect, the number of the plural radiopaque filaments is equal to the total number of sets of first and second filaments.
In a further aspect, embodiments of the disclosure feature an intraluminal device. The intraluminal device comprises a radially expandable body having a proximal end portion and a distal end portion and a control member operable to expand and contract the radially expandable body. The radially expandable body comprises plural elongate ribbons each extending from the proximal end portion to the distal end portion and one or more filaments coupled to the plural elongate ribbons forming a mesh structure.
In various embodiments of the aspect, the plural elongate ribbons are formed by cutting plural slits in a tubular member.
In various embodiments of the aspect, each of the plural ribbons comprises plural attachment features to couple the one or more filaments.
In various embodiments of the aspect, the plural attachment features are arranged to allow the one or more filaments to form plural circular filaments each intersecting the plural elongate ribbons. The plural circular filaments are generally perpendicular to a longitudinal axis of the radially expandable body.
In various embodiments of the aspect, the plural attachment features are arranged to allow the one or more filaments to extend spirally from the proximal end portion to the distal end portion and intersect the plural elongate ribbons.
In various embodiments of the aspect, the plural attachment features are arranged to allow the one or more filaments to sway between two or more elongate ribbons in a sine-wave manner.
In various embodiments of the aspect, the plural elongate ribbons are constructed of a shape memory material.
In various embodiments of the aspect, the plural elongate ribbons are generally evenly spaced apart circumferentially.
In various embodiments of the aspect, the plural elongate ribbons extend spirally from the proximal end portion to the distal end portion in a first direction, and the one or more plural filaments extend spirally from the proximal end portion to the distal end portion in a second direction opposite to the first direction. In a specific embodiment, the plural elongate ribbons are formed by cutting plural slits in a spiral pattern in a tubular member constructed of a shape memory material.
This Summary is provided to introduce selected aspects and embodiments of this disclosure in a simplified form and is not intended to identify key features or essential characteristics of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The selected aspects and embodiments are presented merely to provide the reader with a brief summary of certain forms the invention might take and are not intended to limit the scope of the invention. Other aspects and embodiments of the disclosure are described in the section of Detailed Description.
These and various other aspects, embodiments, features, and advantages of the disclosure will become better understood upon reading of the following detailed description in conjunction with the accompanying drawings.
With reference to the figures, various embodiments of an intraluminal device will now be described. It should be noted that the figures are intended for illustration of embodiments but not for exhaustive description or limitation on the scope of the disclosure. Alternative structures and components will be readily recognized as being viable without departing from the principle of the claimed invention.
Intraluminal Device Including a Spiral Wrap
Embodiments of the disclosure provide an intraluminal device which allows the user to control radial expansion and contraction of the device. The intraluminal device comprises a radially expandable body, or a mesh-like structure, or a continuous spiral wrap. Starting in a thin compact form, the intraluminal device can penetrate through an obstruction such as a clot in a blood vessel. Once the distal portion of the spiral wrap has traveled through a clot and the spiral wrap is incapsulated in the clot, the user can manually expand the spiral wrap. With manual expansion, the user can increase and/or decrease the radial force to help the spiral wrap work its way through the clot. Providing a capability of control of radial expansion of the spiral wrap allows the user to achieve greater penetration of a clot as compared to conventional stent retrievers. The user can expand the spiral wrap more for a larger vessel or less for a smaller vessel. During expansion, the spiral wrap can penetrate radially through the clot and create a hold on the bulk of the clot. The more the spiral wrap expands, the better hold the device has on the clot. Once the spiral wrap has fully expanded, the user can then remove the clot from the vessel by retrieving the spiral wrap. Greater hold on the clot gives greater confidence that the entire clot will be extracted during the first retrieval of the spiral wrap from the patient. Conventional stent retriever relies on the shape memory property of the stent material to expand. Relying solely on shape memory property limits the amount of radial force a stent retriever can achieve and does not allow the user to control of the radial expansion which may be needed for effective penetration and successful removal of a clot through variably sized vessels.
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Radiopaque filaments can be constructed of a material comprising platinum, gold, tantalum, barium, lodin, bismuth, etc., or an alloy containing any of the above metals. In some embodiments, radiopaque filaments may be in the form of drawn filled tubing (DFT) wires, which may include a core of a radiopaque material such as platinum, gold, tantalum etc. and an outer sheath of a non-radiopaque material such as nitinol. Whereas the core of DFT wires provides radiopacity, the outer sheath of DFT wires can provide strength, flexibility, elasticity, and other desirable properties. Non-radiopaque filaments may be constructed of a material comprising nickel, titanium, nickel-titanium alloy such as nitinol, and other suitable materials. Nitinol exhibits flexibility, elasticity, shape memory and other desirable properties, and is a preferred material for constructing non-radiopaque filaments.
For illustration and by way of example, in a non-limiting specific embodiment of the disclosure, an intraluminal device may include 12 filaments, of which 9 are constructed of a non-radiopaque material and the remaining 3constructed of a radiopaque material. The 12 filaments may be grouped in 6 sets or pairs wherein each set or pair contains two filaments twisted or bundled together in extending from the proximal end portion to the distal end portion of the radially expandable body. Of the 6 sets or pairs of filaments, 3 sets extend spirally in a clockwise direction and 3 sets in a counterclockwise direction. Of the 3 sets of filaments that extend spirally in the same direction, each set contains a radiopaque filament and a non-radiopaque filament. At a cross section of the mesh body, a filament of a set of passes between two filaments of another set. As such, a set of two filaments may rotate about a filament of another set, thereby allowing the mesh body to freely expand. The twist between filaments of a set prevents or limits slipping of a filament of another set, thereby allowing the cell of the mesh body to maintain a predetermined size during expansion and contraction of the mesh body.
According to embodiments of the disclosure, the filaments may have a diameter ranging e.g., from 0.003″ to 0.006″ depending on applications. The mesh body may have a minimal diameter when in a thin compact form e.g., about 0.012″, and a maximal diameter when in a large expanded configuration e.g., about 0.019″. it should be noted that the dimensions are provided for understanding of the disclosure and the present claims are not so limited. The expansion of the mesh body can be controlled by operating the control member, allowing the mesh structure to have a diameter ranging from the minimal diameter and the maximal diameter, to adapt to variably sized blood vessels and provide variable radial expansion force for penetration and removal of a clot.
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In a non-limiting specific embodiment, the number of radiopaque filaments in the radially expandable body 210 may be the same as the total number of the sets of first and second filaments. By way of example, the radially expandable body may include totally six sets of filaments (three sets of first filaments and three sets of second filaments) and six radiopaque filaments. In alternative embodiments, the number of radiopaque filaments in the radially expandable body may be different from the total number of the sets of first and second filaments.
Intraluminal Device Including Laser-Cut Ribbons
Embodiments of the disclosure provide an intraluminal device which allows the user to control radial expansion and contraction of a mesh-like structure. The mesh-like structure can be formed by cutting a single tube of a material, optionally in combination of other wires or filaments. The cutting of a single tube can create an expandable body including plural elongate ribbons, either in a straight or spiral form, extending between the proximal end and distal end of the expandable body. The elasticity properties of a shape memory material, such as a nickel-titanium alloy, allow the expandable body to be properly shaped and radially evenly expanded. The ribbons created by cutting a tube may be provided with holes, slits, cuts, or other attachment features to allow additional wires or filaments to be threaded or looped through forming a mesh-like structure. The mesh-like structure can be expanded and/or contracted with a control member such as a pull wire. The pull wire allows the user to control the radial force of the mesh structure, facilitating penetration and removal of a clot from a blood vessel. Conventional stent retrievers consist of a structure made of a laser-cut tube that is expandable to a certain maximal diameter based solely on the shape memory property of the material, but lack the ability of control of the device integration into blood clots.
With reference to
The plural elongate ribbons 312 may be formed by cutting a material from a single tube. By way of example, a pattern of plural slits may be laser-cut in a tubular member. The slits may be cut such that the plural ribbons 312 formed are generally in a straight or one-dimensional form (
The tube or tubular member used for creating elongate ribbons 312 can be constructed of a shape memory material such as a metal alloy comprising nickel (Ni) and titanium (Ti), also known as Nitinol. Nitinol shape memory alloys can be deformed at a low temperature and are able to recover their original, permanent shape when exposed to a high temperature. Tubular members constructed of other shape memory materials can also be used to create elongate ribbons of a radially expandable body.
With reference to
Various embodiments of an intraluminal device have been described. Advantageously, the intraluminal device of the disclosure allows the user to control the outer diameter of a mesh structure, and pulse or manipulate radial force of the mesh structure to facilitate penetration and retrieval of blood clots. The pattern of filament cross sections allows the mesh structure to expand to variable diameters while maintaining a predetermined cell size. This helps create a precise repeatable expansion and radial force. Free and precise expansion allows for ease of application of radial force and creates tactile feedback to the user. In conventional stent retrievers, the cross sections of filaments slip during expansion, causing the size of one cell to be reduced and the size of another cell to be increased. In some conventional stent retrievers, filaments at cross sections weave too tightly into each other, limiting a free expansion state and creating inconsistent performance. The intraluminal device of the disclosure includes radiopaque filament or filaments to assist in holding the cell structure and creating radiopacity for the mesh structure. The intraluminal device of the disclosure also allows for a large cell structure while still maintaining structural integrity, which in turn allows for holding a larger majority of a blood clot together. Keeping a larger majority of the clot intact ensures that the entire clot can be removed the first time and small pieces do not detach. The intraluminal device allows for a distal portion with a tighter weave pattern serving as a backstop when removing a clot. A tight weave pattern creates smaller cells and decreases the possibility for a clot to dislodge from the mesh structure during extraction. If a clot does slip, the tight weave backstop can catch the clot and pull it along.
In use, an intraluminal device of the disclosure may be delivered to a target site using a microcatheter. A microcatheter may be first introduced to the target site through an access in the patient using a guiding catheter. The microcatheter may be guided to the target site through the use of a guidewire. The guidewire may be visible via fluoroscopy, allowing the microcatheter to be reliably advanced over the guidewire to the target site. Once the target site has been accessed with the microcatheter tip, the guidewire can be withdrawn, clearing the lumen of the microcatheter. The intraluminal device of the disclosure can be placed into the proximal open end of the microcatheter and advanced through the microcatheter. In delivery to the target site, the intraluminal device can be in a thin compact form to allow the device to penetrate through e.g., a blood clot at the target site. By using an operating device such as handle, the user may pulse or manipulate the radial force of the mesh structure to aid the device to travel through the clot. Once the mesh body or at least the distal portion of the mesh body has travelled through and is incapsulated in the clot, the user can expand the device. The user may control the radial expansion of the device, for example, expand the device more for a larger vessel or less for a smaller vessel. During expansion, the mesh structure penetrates radially through the clot and creates a hold on the bulk of the clot. The user can then remove the clot from the vessel by retrieving the intraluminal device.
Various embodiments of an intraluminal device have been described with reference to figures. It should be noted that the figures are intended to facilitate illustration and some figures are not necessarily drawn to scale. Further, in the figures and description, specific details may be set forth in order to provide a thorough understanding of the disclosure. It will be apparent to one of ordinary skill in the art that some of these specific details may not be employed to practice embodiments of the disclosure. In other instances, well known components or process steps may not be shown or described in detail in order to avoid unnecessarily obscuring embodiments of the disclosure.
All technical and scientific terms used herein have the meaning as commonly understood by one of ordinary skill in the art unless specifically defined otherwise. As used in the description and appended claims, the singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. The term “or” refers to a nonexclusive “or” unless the context clearly dictates otherwise. The term “proximal” and its grammatically equivalent refers to a position, direction or orientation towards the user or physician's side. The term “distal” and its grammatically equivalent refers to a position, direction or orientation away from the user or physician's side. The term “first” or “second” etc. may be used to distinguish one element from another in describing various similar elements. It should be noted the terms “first” and “second” as used herein include references to two or more than two. Further, the use of the term “first” or “second” should not be construed as in any particular order unless the context clearly dictates otherwise.
Those skilled in the art will appreciate that various other modifications may be made. All these or other variations and modifications are contemplated by the inventors and within the scope of the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63295340 | Dec 2021 | US |
