Patent Application
20230301672
This application relates generally to medical catheters and methods of making and using medical catheters. In particular, various embodiments of an aspiration catheter useful in thrombectomy and other medical procedures are described.
Stroke is one of the leading causes of death worldwide with an annual mortality rate of more than five million. In the United State, every year about 800, 000 people have a stroke. With all the medical advancement, over 17% of the patients still die. Patients who survive stroke may end up with long-term disability, creating immense economic and social consequences.
An ischemic stroke occurs when clots or other occlusions block the blood vessels to the brain. A hemorrhagic stroke happens when an artery in the brain ruptures. In either case, parts of the brain become damaged or die, causing brain damage, long-term disability, or death. Ischemic stroke is the more common type of stroke.
Various medical procedures are known and have been used in treating stroke. For example, in a thrombectomy procedure for treating ischemic stroke, an aspiration catheter may be used to remove occlusions such as clots from blood vessels. While significant advancement in aspiration thrombectomy has been achieved, there remains a general need for improvement. For example, it would be desirable to provide an aspiration catheter with improved flexibility and trackability to navigate the complex, tortuous cerebral anatomy in performing various medical procedures including removing occlusions or clots to treat stroke.
In one aspect, embodiments of the disclosure feature a catheter. In general, an embodiment of the catheter comprises an elongate tubular body having a proximal end portion and a distal end portion. The elongate tubular body comprises an inner liner and one or more outer layers. The inner liner comprises a first surface defining a lumen of the elongate tubular body and a second surface. The one or more outer layers are disposed over the second surface of the inner liner. The inner liner has a first thickness at the proximal end portion of the elongate tubular body and a second thickness at the distal end portion of the elongate tubular body, where the second thickness is smaller than the first thickness.
In various embodiments of the aspect, the second surface of the inner liner defines a first outer diameter at the proximal end portion of the elongate tubular body and a second outer diameter at the distal end portion of the elongate tubular body, wherein the second outer diameter is smaller than the first outer diameter.
In an embodiment, the first outer diameter defined by the second surface of the inner liner at the proximal end portion is substantially constant, the second outer diameter defined by the second surface of the inner liner at the distal end portion is substantially constant, and the second surface of the inner liner comprises a transition section having a tapering function from the first outer diameter to the second outer diameter.
In another embodiment, the first outer diameter defined by the second surface of the inner liner at the proximal end portion is substantially constant, the second outer diameter defined by the second surface of the inner liner at the distal end portion is substantially constant, and the second surface of the inner liner comprises a transition section having a step function from the first outer diameter to the second outer diameter.
In a further embodiment, the first surface of the inner liner defines a diameter of the lumen substantially constant between the proximal end portion and the distal end portion of the elongate tubular body.
In various embodiments of the aspect, the inner liner is constructed from a material comprising polytetrafluoroethylene (PTFE).
In various embodiments of the aspect, the inner liner is provided with plural voids between the first surface and the second surface of the inner liner.
In some embodiments, the plural voids are located at the distal end portion of the elongate tubular body. In some embodiments, the plural voids are located throughout the entire length of the elongate tubular body from the proximal end portion to the distal end portion.
In another aspect, embodiments of the disclosure feature a catheter. In general, an embodiment of the catheter comprises an elongate tubular body having a proximal end portion and a distal end portion. The elongate tubular body comprises an inner liner and one or more outer layers. The inner liner comprises a first surface defining a lumen of the elongate tubular body and a second surface. The one or more outer layers are disposed over the second surface of the inner liner. The inner liner is provided with plural voids between the first surface and the second surface of the inner liner.
In various embodiments of the aspect, the plural voids are located at the distal end portion of the elongate tubular body.
In various embodiments of the aspect, the plural voids are located throughout the entire length of the elongate tubular body from the proximal end portion to the distal end portion.
In various embodiments of the aspect, the inner liner comprises a first thickness at the proximal end portion of the elongate tubular body and a second thickness at the distal end portion of the elongate tubular body. The second thickness is smaller than the first thickness.
In various embodiments of the aspect, the second surface of the inner liner defines a first outer diameter at the proximal end portion of the elongate tubular body and a second outer diameter at the distal end portion of the elongate tubular body. The second outer diameter is smaller than the first outer diameter. The first outer diameter defined by the second surface of the inner liner at the proximal end portion can be substantially constant, and the second outer diameter defined by the second surface of the inner liner at the distal end portion can be substantially constant. In an embodiment, the second surface of the inner liner further comprises a transition section having a tapering function from the first outer diameter to the second outer diameter. In another embodiment, the second surface of the inner liner further comprises a transition section having a step function from the first outer diameter to the second outer diameter.
In various embodiments of the aspect, the inner liner is constructed from a material comprising polytetrafluoroethylene (PTFE).
In various embodiments of the aspect, the elongate tubular body comprises a length between the proximal end portion and the distal end portion, and the inner liner extends the length of the elongate tubular body and comprises a substantially constant thickness along the length. The plural voids can be located at the distal end portion of the elongate tubular body. The plural voids can also be located throughout the entire length of the elongate tubular body.
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 aspiration catheter, system, and method will now be described. The figures are intended to facilitate illustration and are not necessarily drawn to scale. Certain specific details may be set forth in the figures and description 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, structures, materials, components, systems, and/or operations often associated with intravascular procedures are not shown or described in detail to avoid unnecessarily obscuring embodiments of the disclosure.
Embodiments of the disclosure provide an aspiration catheter including an inner liner constructed to improve the flexibility and trackability of the catheter desirable for performing various medical procedures, including aspiration thrombectomy in the cerebral anatomy. The inner liner of the aspiration catheter can be constructed with a smaller thickness at the tip or distal section of the catheter to reduce stiffness. This can be achieved by selectively removing a portion of the inner liner at the tip or distal section via mechanical, thermal, or chemical means, and returning to an original or initial thickness of the remaining section via a step or tapering function. The thinning of the inner liner can also be achieved by selectively depositing layers on a mandrel to build up the inner liner and at some point, discontinuing deposition of the material at the distal end or section of the inner liner. Alternatively, or additionally, small voids or bubbles can be created in the inner liner to increase the flexibility of the catheter. The bubbles can be formed in the inner liner throughout the entire length of the catheter, or just through a distal end section. By forming bubbles in the inner liner, the liner material is replaced with empty space, resulting in the same effect as thinning the inner liner and thus improving the flexibility of the catheter. Generally, the inner liner of a catheter is made of a stiff material. Reducing the thickness of the inner liner at the distal end of a catheter, and/or, creating voids or bubbles in the inner liner can reduce the stiffness of the liner, thereby improving the flexibility and trackability of the overall catheter. The improved flexibility and trackability can help the user navigate the catheter through the complex, tortuous vasculature at the cerebral anatomy, thereby facilitating medical procedures including aspiration thrombectomy to treat stroke.
It should be pointed that while the term “aspiration” is used in describing various embodiments of the disclosure, the catheter, system, and method described herein can be used in medical procedures other than or in addition to aspiration. For example, the catheter can be used to deliver therapeutical agents, fluids or medical devices to a treatment site in a vasculature, or as a support catheter to provide a conduit that facilitates and guides delivery of other devices such as interventional devices. Further, it should be appreciated that while embodiments of the disclosure may be described in conjunction with an aspiration thrombectomy procedure in the cerebral anatomy, the catheter, system, and method described herein can be configured to access, deliver agents or devices, or perform procedures in other anatomies such as peripheral and coronary anatomies.
The catheter device 102 may include an aspiration catheter 110 configured to access and aspirate an occlusion or clot 101 from a treatment site. The aspiration catheter 110 comprises an elongate tubular body 112 defining a working lumen 114 extending between a proximal end portion 116 and a distal end portion 118 of the elongate tubular body 112. The proximal end portion 116 of the aspiration catheter 110 may be coupled to the hub 106, forming a fluidic communication between the working lumen 114 and the vacuum source 104. As will be described in greater detailed below, the aspiration catheter 110 of the disclosure has a higher degree of flexibility and trackability, and is capable of providing an access to locations even through the extreme tortuosity at the cerebral anatomy. As such, the aspiration catheter 110 of the disclosure allows for delivering aspirational forces to a treatment site of extreme tortuosity, and/or, for delivering interventional devices such as a stent, stent retriever, flow diverter, or other devices to a treatment site of extreme tortuosity.
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The inner liner 120 or 220 can be constructed from a lubricious or low-friction material to provide a smooth surface for advancement of devices or objects through the inner lumen. Suitable lubricious materials include but are not limited to polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), and other suitable polymeric materials.
The one or more outer layers 122, 124 may include a jacket or sheath layer 122 to provide mechanical integrity to the aspiration catheter 110. The jacket layer 122 may be constructed from a material such as a thermoplastic elastomer (TPE) e.g., polyether block amide, thermoplastic polyurethane, polyethylene, nylon, or the like. The jacket layer 122 may extend from the proximal end portion 116 to the distal end portion 118 of the elongate tubular body 112.
The one or more outer layers 122, 124 may also include a reinforcement layer 124 incorporated between the inner liner 120 or 220 and the jacket layer 122. The reinforcement layer 124 can be constructed to prevent kinking or flattening of the inner lumen 114 of the elongate tubular body 112 in navigation through a tortuous vasculature. The reinforcement layer 124 can be made from metal such as stainless steel, nitinol, or from polymers, or any combinations thereof. The reinforcement layer 124 can be in a structure of a coil or braid, or flexible tubing with a laser-cut pattern, or a hypotube such as a cut nitinol hypotube or cut rigid polymer, or the like. The reinforcement layer 124 may extend from the proximal end portion 116 to the distal end portion 118 of the elongate tubular body 112, or substantially entire length of the elongate tubular body 112. Alternatively, the reinforcement layer 124 may extend partially along the elongate tubular body 112. For example, the reinforcement layer 124 may be omitted in a portion of the proximal end portion 116 of the elongate tubular body 112.
The inner liner 120 or 220 and the one or more outer layers 122, 124 may be configured to provide the catheter 110 with varying flexibilities, rigidity, hardness, and/or other properties in/along the elongate tubular body 112. For example, the inner liner 102 or 220 and the one or more outer layers 122, 124 may be configured to render the proximal end portion 116 of the catheter 110 harder or more rigid to improve the pushability of the aspiration catheter 110, and/or render the distal end portion 118 of the catheter 110 more flexible to facilitate navigating through a tortuous vasculature.
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The thickness of the inner liner 120 can be varied by removing materials from selected portions of an inner liner using various means including mechanical means, thermal means, electrical means, chemical means, or any combination thereof. For example, a distal end portion of an inner liner can be thinned via an abrasive process using a grinding workpiece, or by cutting using a micro-cutting tool. As another example, the material of an inner liner can be selectively removed via electrical discharge machining (EMD) using a series of rapidly recurring current discharges between electrodes. The material of an inner liner can also be selectively removed by immersing e.g., a distal end portion of the inner liner in a chemical solution. Alternatively, or additionally, the thickness of an inner liner can be varied or controlled by selective deposition of liner materials. For example, using a mandrel, a thickness of the inner liner can be built up and at some point, deposition of the liner material can be discontinued at a distal end portion of the inner liner, but continued at a proximal end portion of the inner liner.
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The bubbles or voids 222 can be created in the inner liner 220 using various methods known in the art, including e.g., ultrasound extraction, flow boiling and condensation, aeration, bubble nucleation, mechanical agitation, extrusion, and so on. By way of example, in an extrusion method, a dispersion of e.g., a polymeric material may pass a commercially available mini-extruder through a porous membrane to arrive at a dispersion of monodispersed vesicles. Using the extrusion technique, nanobubbles may be uniformly formed in e.g., a PTFE layer. The various techniques of forming bubbles or microbubbles are generally known in the art, and thus their detailed description is omitted herein to avoid obscuring the description of embodiments of the disclosure.
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Various embodiments of an aspiration catheter, system, and method have been described with reference to figures. 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, components, and materials will be readily recognized as being viable without departing from the principle of the claimed invention.
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.
This application claims priority to U.S. provisional patent application No. 63/322,508 filed Mar. 22, 2022 entitled “Aspiration Catheter with Lubricious Inner Liner with an Improved Flexible Distal Tip for Improved Trackability,” the disclosure of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63322508 | Mar 2022 | US |
