Patent Application
20250040955
The present disclosure generally relates to a tissue-removing catheter.
Tissue-removing catheters are used to remove unwanted tissue in body lumens. As an example, atherectomy catheters are used to remove material from a blood vessel to open the blood vessel and improve blood flow through the vessel. This process can be used to prepare lesions within a patient's coronary artery to facilitate percutaneous coronary angioplasty (PTCA) or stent delivery in patients with severely calcified coronary artery lesions. Atherectomy catheters typically employ a rotating element which is used to abrade or otherwise break up the unwanted tissue.
In one aspect, the present disclosure provides a tissue-removing catheter for removing tissue in a body lumen. The tissue-removing catheter includes an elongate drive member and a tissue-removing element. The elongate drive member has proximal and distal ends with a length and a longitudinal axis extending between the proximal and distal ends. The elongate drive member is sized and shaped to be received in the body lumen and rotates about its longitudinal axis. The elongate drive member further includes first and second longitudinal portions. The first longitudinal portion is proximal to and stiffer than the second longitudinal portion. The tissue-removing element is operatively coupled to the distal end of the elongate drive member and rotates by the elongate drive member to remove the tissue in the body lumen.
Corresponding reference characters indicate corresponding parts throughout the drawings.
The present disclosure is generally directed to a tissue-removing catheter configured to remove tissue in a body lumen. In some examples, the catheter is a rotational atherectomy device suitable for removing (e.g., abrading, cutting, excising, ablating, etc.) occlusive tissue (e.g., embolic tissue, plaque tissue, atheroma, thrombolytic tissue, stenotic tissue, hyperplastic tissue, neoplastic tissue, etc.) from a vessel wall (e.g., coronary arterial wall, etc.). The catheter may be used to facilitate percutaneous transluminal coronary angioplasty (PTCA) or the subsequent delivery of a stent. Features of the disclosed examples may also be suitable for treating chronic total occlusion (CTO) of blood vessels, and stenosis of other body lumens and other hyperplastic and neoplastic conditions in other body lumens, such as the ureter, the biliary duct, respiratory passages, the pancreatic duct, the lymphatic duct, and the like. Neoplastic cell growth may occur as a result of a tumor surrounding and intruding into a body lumen. Removal of such material can thus be beneficial to maintain patency of the body lumen.
In general, examples of the tissue-removing catheters described herein include an elongate catheter body having proximal and distal end portions, a rotatable tissue-removing element coupled to the distal end portion of the catheter body and configured to be rotated about its axis for removing tissue from the body lumen, and a handle coupled to the proximal end portion of the catheter body. The catheter body includes first and second longitudinal portions having different stiffness. In particular, the first longitudinal portion is proximal of the second longitudinal portion, and the first longitudinal portion is stiffer than the second longitudinal portion. Through this construction, the first longitudinal portion provides stiffness to the catheter body for suitable “pushability” of the catheter, and the second longitudinal portion provides flexibility to the catheter body for suitable “navigation” or “trackability” of the catheter. As used in the art, “pushability” refers to relationship between push force applied to the proximal end portion of the catheter and advancement of the catheter body in the body lumen. As used in the art, the “navigation” or “trackability” of the catheter body refers to the ability of the catheter body to move through turns or obstructions in the lumen/anatomy. The first longitudinal portion may also have a greater strength than the second longitudinal portion. Overall, and in general, the first longitudinal portion may be more robust to dynamic loading.
Referring to the drawings, and in particular
The catheter body 12 includes first and second longitudinal portions, generally indicated at 12A and 12B, respectively, having different stiffness. In particular, the first longitudinal portion 12A is proximal of the second longitudinal portion 12B, and the first longitudinal portion 12A is stiffer than the second longitudinal portion 12B. The catheter body 12 of the illustrated catheter 10 includes an elongate drive member, generally indicated at 18, and an elongate inner liner, generally indicated at 20, each of which extend along the length of the catheter body. In general, as shown best in
In one or more embodiments, the catheter 10 includes an isolation sheath. The catheter body 12 is disposed in the isolation sheath, and the catheter body is longitudinally movable relative to and in the isolation sheath. The isolation sheath isolates the body lumen from at least a portion of the drive member 18 and inner liner 20. In one example, the isolation sheath has an inner diameter of about 0.050 inches (1.27 mm), an outer diameter of about 0.055 inches (1.4 mm), and a length of about 1500 mm (59 inches). The isolation sheath can have other dimensions without departing from the scope of the disclosure. In one example, the isolation sheath is made from Polytetrafluorethylene (PTFE). Alternatively, the isolation sheath may comprise a multi-layer construction. For example, the isolation sheath may comprise an inner layer of perfluoroalkoxy alkane (PFA), a middle braided wire layer, and an outer layer including a Pebax® (a polyether-block-amide available from Arkema, The King of Prussia, Pennsylvania).
The elongate drive member 18 has length and a longitudinal axis extending between proximal and distal ends of the drive member. In the present illustrated example, the elongate drive member 18 includes first and second longitudinal portions (e.g., proximal and distal longitudinal portions) generally indicated at 18A and 18B, respectively, having different stiffness. In particular, the first longitudinal portion 18A is proximal of the second longitudinal portion 18B, and the first longitudinal portion 18A is stiffer than the second longitudinal portion 18B. In general, the first longitudinal portion 18A of the elongate drive member 18 at least partially defines the first longitudinal portion 12A of the catheter body 12, and the second longitudinal portion 18B of the elongate drive member at least partially defines the second longitudinal portion 12B of the catheter body. In one example, the first longitudinal portion 18A of the drive member 18 extends at least about 90% of the length of the drive member 18, for example, between about 90% and 99% of the length of the drive member, and the second longitudinal portion 18B of the drive member extends from about 10% to about 1% of the length of the drive member 18.
In one example, the first longitudinal portion 18A of the drive member 18 comprises a first drive coil (e.g., stainless steel coil), and the second longitudinal portion 18B of the drive member comprises a second drive coil (e.g., stainless steel coil), as best seen in
The presently illustrated elongate drive member 18 includes a coupler 24 coupling the first longitudinal portion 18A of the drive member to the second longitudinal portion 18B such that rotation of the first longitudinal portion 18A is imparted to the second longitudinal portion 18B. For example, as shown in
The present illustrated coupler 24 shown in
The bearing assembly 25 of the coupler 24 includes a bushing 27 secured to the inner liner 20, and one or more bearings 29 (e.g., proximal and distal bearings) rotatably engaging the bushing. The inner liner 20 extends through the bushing 27 and may be secured thereto such as by adhesive or in other ways. In one example, the bushing 27 is made from polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE). In another example, the bushing 27 is made from polyetheretherketone (PEEK) with carbon fiber filler. The PEEK/carbon fiber bushing 27 may be preferred for its performance in high temperatures, low coefficient of friction, and wear resistance. For example, the PEEK/carbon fiber bushing 27 can maintain its structural integrity at temperatures exceeding 300° C. However, the bushing 27 can be formed from other material without departing from the scope of the disclosure. The proximal and distal bearings 29 are ring-shaped (e.g., annular) and surround proximal and distal outer surfaces of the bushing 27. In one example, the bearings 29 are made from zirconia (zirconium oxide) or other material. The proximal and distal bearings 29 are secured within recesses of the coupler body, and a center shoulder of the bushing 27 is disposed longitudinally between the proximal and distal bearings 29. The proximal and distal bearings 29 rotate with the coupler body and the drive member 18 and ride on the outer surface of the bushing 27. Through this construction, the coupler 24 inhibits longitudinal movement of the inner liner 20 relative to the drive member 18, the coupler body, and the tissue-removing element 14 while enabling rotation of the drive member and the tissue-removing element 14 relative to the inner liner 20. The coupler 24 may have other constructions configured to inhibit longitudinal movement of the inner liner 20 relative to the drive member 18 and the tissue-removing element 14 while enabling rotation of the drive member 18 and the tissue-removing element 14 relative to the inner liner 20.
In the present illustrated example, the inner liner 20 also includes first and second longitudinal portions 20A, 20B (e.g., proximal and distal longitudinal portions) having different stiffness. In particular, the first longitudinal portion 20A is proximal of the second longitudinal portion 20B, and the first longitudinal portion is stiffer than the second longitudinal portion. In this example, the first longitudinal portion 20A of the inner liner 20, in combination with the first longitudinal portion 18A of the elongate drive member 18, at least partially defines the first longitudinal portion 12A of the catheter body 12, and the second longitudinal portion 20B of the inner liner, in combination with the second longitudinal portion 18B of the elongate drive member, at least partially defines the second longitudinal portion 12B of the catheter body. In other examples, the inner liner 20 may have a uniform stiffness along its length.
In one example, material(s) of the proximal and distal longitudinal portions 20A, 20B of the inner liner 20 may be different, leading to proximal longitudinal portion of the inner liner being stiffer than the distal longitudinal portion. For example, the proximal portion 20A of the inner liner 20 may comprise or consist of an outer layer of one or more of a polyimide, a polyamide (e.g., nylon 12), a polyether block amide (e.g., PEBAX, such as PEBAX 7233); and inner layer comprising a braided metal; and an inner liner comprising one or more of fluorinated ethylene propylene, polytetrafluoroethylene, high density polyethylene, polycarbonate urethane, or polyether ether ketone. In another example, different structures of the proximal and distal longitudinal portions 20A, 20B of the inner liner 20 may enable the proximal longitudinal portion to be stiffer than the distal longitudinal portion. The inner liner 20 may be formed with the same material along its length, and the proximal longitudinal portion 20A may include a braid (e.g., metal braid) coupled to be a material to make the proximal longitudinal portion stiffer than the distal longitudinal portion 20B that does not include the braid or other structure that adds stiffness to the portion. For example, the inner liner 20 may comprise an inner PTFE layer, and an outer layer of polyimide. The PTFE inner layer provides the inner liner 20 with a lubricous interior which aids in the passing of the guidewire 22 though the inner liner. The outer polyimide layer provides wear resistance as well as having a lubricous quality which reduces friction between the inner liner 20 and the drive coil 18. Additionally, a lubricious film, such as silicone, can be added to the inner liner 20 to reduce friction between the inner liner and the drive coil 18. The proximal longitudinal portion 20A of the inner liner 20 includes braid (e.g., braided stainless steel) intermediate the inner and outer layers to provide rigidity and strength to the proximal longitudinal portion. The distal longitudinal portion 20B of the inner liner 20 may be free from the braid or have a braid with varied density which transitions from stiff to flexible to provide suitable flexibility to the distal longitudinal portion. The inner liner 20 may be of other constructions.
In one example, the inner liner 20 has an inner diameter of about 0.016 inches (0.4 mm), an outer diameter of about 0.021 inches (0.5 mm), and a length of about 59 inches (1500 mm). The inner diameter of the inner liner 20 provides clearance for the standard 0.014-inch guidewire 22. The outer diameter of the inner liner 20 provides clearance for the drive coil 18 and tissue-removing element 14. Having a space between the inner liner 20 and the drive coil 18 reduces friction between the two components as well as allows for saline perfusion between the components.
The tissue-removing element 14 engages and removes tissue in the body lumen when centered in the lesion. Any suitable tissue-removing element 14 for removing tissue in the body lumen as it is rotated may be used in one or more examples. In the illustrated example, the tissue-removing element 14 may comprise an abrasive burr configured to abrade tissue in the body lumen when the drive (e.g., motor), rotates the abrasive burr. In other examples, the tissue-removing element 14 may include one or more cutting elements having smooth or serrated cutting edges, a macerator, a thrombectomy wire, etc. In the illustrated example, a plain bearing 31 is received in and secured to the tissue-removing element 14 and is configured to engage and rotate about the inner liner 20.
As described above, the tissue-removing element 14 is coupled to (e.g., directly coupled to) the distal end of the distal longitudinal portion 18B of the drive member 18. When coupled, rotation from the drive member 18 is transferred to the tissue-removing element 14. The tissue-removing element 14 may be welded and/or crimped and/or adhered to the drive member 18. The tissue-removing element 14 may be secured to the drive member 18 in other ways. In one or more examples of catheter 10, a connector (e.g., a hypotube) may be used to secure the drive member to the tissue-removing element 14.
In one example, to remove tissue in the body lumen of a subject, a practitioner inserts the guidewire 22 into the body lumen of the subject, to a location distal of the tissue that is to be removed. Subsequently, the practitioner inserts the proximal end portion of the guidewire 22 through a guidewire lumen of the inner liner 20 and through the handle 16 so that the guidewire extends through a proximal port in the handle. With the catheter 10 loaded onto the guidewire 22, the practitioner advances the catheter along the guidewire until the tissue-removing element 14 is positioned proximal and adjacent the tissue. When the tissue-removing element 14 is positioned proximal and adjacent the tissue, the practitioner actuates the motor using an actuator to rotate the drive member 18 and the tissue-removing element 14 mounted on the drive coil. The tissue-removing element 14 abrades (or otherwise removes) the tissue in the body lumen as it rotates. While the tissue-removing element 14 is rotating, the practitioner may selectively move the drive coil 18 and inner liner 20 distally along the guidewire 22 and relative to an outer sheath to abrade the tissue and, for example, increase the size of the passage through the body lumen. The practitioner may also move the drive coil 18 and inner liner 20 proximally along the guidewire 22, and may repetitively move the components in distal and proximal directions to obtain a back-and-forth motion of the tissue-removing element 14 across the tissue by sliding an advancer. During the abrading process, the coupling allows the drive coil 18 and tissue-removing-element 14 to rotate around the inner liner 20. The inner liner 20 also isolates the guidewire 22 from the rotating drive coil 18 and tissue-removing element 14 to protect the guidewire from being damaged by the rotating components. As such, the inner liner 20 is configured to withstand the torsional and frictional effects of the rotating drive coil 18 and tissue-removing element 14 without transferring those effects to the guidewire 22. When the practitioner is finished using the catheter 10, the catheter can be withdrawn from the body lumen and unloaded from the guidewire 22 by sliding the catheter proximally along the guidewire. The guidewire 22 used for the abrading process may remain in the body lumen for use in a subsequent procedure.
Referring to
As with the prior coupler 24, the present illustrated coupler 124 couples together the proximal and distal longitudinal portions 118A, 118B of the drive member 118 such that rotation of the first longitudinal portion is imparted to the second longitudinal portion. For example, as best shown in
As illustrated, the coupler 124 does not include the bearing assembly 25. Instead, a bearing assembly 125 is disposed in the tissue-removing element 114. The bearing assembly 125 includes a bushing 127 secured to the inner liner 120, and one or more bearings (e.g., proximal and distal bearings) rotatably engaging the bushing. The constructions of the bushing 127 and bearing(s) 129 may be the same as the bushing 27 and bearing(s) 29. The inner liner 120 extends through the bushing 127 and may be secured thereto such as by adhesive or in other ways. The proximal and distal bearings 129 are ring-shaped (e.g., annular) and surround proximal and distal outer surfaces of the bushing 127. The proximal and distal bearings 129 are secured within recesses of the tissue-removing element 114, and a center shoulder of the bushing 127 is disposed longitudinally between the proximal and distal bearings. The proximal and distal bearings 129 rotate with the coupler body and the drive member 118 and ride on the outer surface of the bushing 127. Through this construction, the coupler 124 inhibits longitudinal movement of the inner liner 120 relative to the drive member 118 and the tissue-removing element 114 while enabling rotation of the drive member and the tissue-removing element relative to the inner liner. The coupler 124 may have other constructions configured to inhibit longitudinal movement of the inner liner 120 relative to the drive member 118 and the tissue-removing element 114 while enabling rotation of the drive member and the tissue-removing element relative to the inner liner. In the illustrated example, a wrap 126 may be disposed at the transition of the first and second longitudinal portions 120A, 120B of the inner liner 120 to strengthen the inner liner at the transition and protect the liner from any edges within the coil/coupler which may cause damage. It is understood that the wrap 126 may be omitted. It is also understood that the inner liner 120 may have a uniform stiffness along its length.
Referring to
The illustrated catheter 210 includes an inner liner 220 with a uniform stiffness along its length. In other examples, the inner liner 220 may have a non-uniform stiffness along its length, similar to the previous examples. The illustrated catheter 210 includes the drive member 218 that includes a drive body (e.g., a drive coil) and a laminate 228 disposed over a first longitudinal portion 218A of the drive body. The drive coil 218 has a uniform stiffness along its length; however, the laminate 228 over the first longitudinal portion 218A of the drive coil 218 increases the stiffness of the first longitudinal portion such that the stiffness of the first longitudinal portion is greater than a second longitudinal portion 218B of the drive coil that is unlaminated. This construction provides the catheter body 212 with the first (proximal) longitudinal portion 212A being stiffer than the second (distal) longitudinal portion 212B such that the first longitudinal portion provides suitable pushability and the second longitudinal portion provides suitable navigation. Suitable material for the laminate includes, but is not limited to a polyimide, a polyamide (e.g., nylon 12), a polyurethane, a polyether block amide (e.g., PEBAX, such as PEBAX 7233 or PEBAX 7033), fluorinated ethylene propylene, polytetrafluoroethylene, high density polyethylene, polycarbonate urethane, or polyether ether ketone.
Referring to
The illustrated drive coil 318 includes first and second longitudinal portions generally indicated at 318A and 318B, respectively, and may have a uniform stiffness along its length; however, post-processing over the second longitudinal portion of the drive coil decreases the stiffness of the second longitudinal portion such that the stiffness of the first longitudinal portion of the drive coil that is not post processed is greater than a second proximal longitudinal portion. As shown, in one example the catheter 310, decrease in stiffness of the drive coil 318 includes post processing gaps 330 in the second longitudinal portion 318B of the drive coil. For example, but not limiting to, targeted and discrete filars can be removed to create gaps 330 in the second longitudinal portion 318B of the drive coil 318, as shown. In some examples, post processing may be imparted by, for example, but not limiting to, laser ablation, welding, or discrete stretching of the drive coil 318 in certain areas, providing a change in stiffness of the second longitudinal portion of the coil. This construction provides the catheter body 312 with the first (proximal) longitudinal portion 312A being stiffer than the second (distal) longitudinal portion 312B such that the first longitudinal portion provides suitable pushability and the second longitudinal portion provides suitable navigation.
Referring to
The illustrated drive coil 418 includes first and second longitudinal portions generally indicated at 418A and 418B, respectively, of different stiffness. The illustrated inner liner 420 includes first and second longitudinal portions generally indicated at 420A and 420B, respectively, of different stiffness. For example, as shown, a proximal end of the second longitudinal portions 418B, 420B of the drive coil 418 and the inner liner 420 are directly coupled to a distal end of the first longitudinal portion 418A, 420B of the drive coil and the inner liner by, for example but not limiting to welding (e.g., butt welding), crimping, and/or adhering.
In this example, the first longitudinal portion 420A of the inner liner 420, in combination with the first longitudinal portion 418A of the elongate drive member 418, at least partially defines the first longitudinal portion 412A of the catheter body 412, and the second longitudinal portion 420B of the inner liner, in combination with the second longitudinal portion 418B of the elongate drive member, at least partially defines the second longitudinal portion 412B of the catheter body. This construction provides the catheter body 412 with the first (proximal) longitudinal portion 412A being stiffer than the second (distal) longitudinal portion 412B such that the first longitudinal portion provides suitable pushability and the second longitudinal portion provides suitable navigation.
The couplers 24 and 124 described with reference to
When introducing elements of the present invention or the one or more example(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
As various changes could be made in the above apparatuses, systems, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/051390 | 11/30/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63284387 | Nov 2021 | US |
