Endoscopic catheter device

Abstract

To provide catheters that are hardly compressed along their length by sufficiently securing column strength for effective puncturing.SOLUTION: A device may include a catheter 200 and a support tube 210. The catheter includes a lumen extending therethrough. The catheter is sized and shaped to extend through an endoscopic shaft to a target tissue within a living body. The lumen is sized and shaped for receiving a puncturing device therethrough. The catheter includes a first catheter portion. The first catheter portion is distal to a second catheter portion. The first catheter portion is formed as a braided polymer tube and the second catheter portion is formed of metal. The first catheter portion has a flexible curved distal end. The device comprises the support tube.The support tube is fixed about an outer surface of a proximal end of the first catheter portion and an outer surface of a distal end of the second catheter portion.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to endoscopic catheter devices, and in particular to microcatheters for use in ultrasound endoscopic access procedures. [Background technology]

[0002] Endoscopic ultrasound (EUS) access procedures are often performed to access patient anatomical structures such as the bile duct, pancreatic duct, pancreatic fluid reservoir, etc., to relieve blockages, for example by inserting a stent. Curved (J-tip) catheters are often used for such procedures. The catheters can be rotated so that the curved distal end of the catheter faces in a desired direction, for example down the lumen of a duct, to deliver a guidewire to a target site within the body. However, existing catheters may exhibit limitations that make them unsuitable for certain applications. For example, some catheters may be prone to compression in length due to insufficient column strength for effective puncture. Summary of the Invention

[0003] The present disclosure relates to an apparatus that may include a catheter. The catheter includes a lumen extending therethrough. The catheter is sized and shaped to extend through an endoscope shaft to a target tissue in a living body. The lumen is sized and shaped to receive a puncture device therethrough. The catheter includes a first catheter portion, the first catheter portion distal to a second catheter portion. The first catheter portion and the second catheter portion are formed from different materials. The first catheter portion has a flexible, curved distal end.

[0004] In one embodiment, the device may also include a support tube secured about an outer surface of the proximal end of the first catheter portion and an outer surface of the distal end of the second catheter portion. In one embodiment, the first catheter section is formed from a braided polymer and the second catheter section is formed from Nitinol.

[0005] In one embodiment, the support tube is formed from flexible laser cut steel. In one embodiment, the apparatus further includes a layer of electrical insulation surrounding the support tube. In one embodiment, the first catheter section and the second catheter section are butted together at a butt joint and joined to the support tube.

[0006] In one embodiment, the device further comprises an echogenic material on the flexible distal end and / or the support tube. In one embodiment, the echogenic material is a coating comprising particles suspended in an acoustically transparent material.

[0007] In one embodiment, the echogenic material is a coiled or braided wire or polymer that is wrapped around the distal end. In one embodiment, the apparatus further includes a puncture device sized and shaped to pass through the lumen of the catheter and extend distally from the curved distal end, the puncture device straightening the curved distal end as it extends through the curved distal end such that when the puncture device punctures the access hole into the target tissue, the straightened distal end follows the puncture device into the access hole.

[0008] In one embodiment, the device further includes an electrosurgical sheath that is slidable longitudinally along the exterior of the catheter and support tube, the electrosurgical sheath having an electrosurgical tip for electrosurgically widening the access hole when the electrosurgical sheath is slid over the curved distal end and an electric current is applied.

[0009] In one embodiment, the proximal end of the first catheter section has a reduced outer diameter relative to the outer diameter of the distal end of the first catheter section. In one embodiment, the second catheter section has an outer diameter approximately equal to the reduced outer diameter of the proximal end of the first catheter section.

[0010] In one embodiment, the support tube has an outer diameter approximately equal to the outer diameter of the distal end of the first catheter section. In one embodiment, the device further includes a polymer that surrounds one of the outer surfaces of the proximal end of the first catheter section and the distal end of the second catheter section when the outer surfaces are not aligned.

[0011] In one embodiment, one of the edges of the inner surface of the proximal end of the first catheter section and the inner surface of the distal end of the second catheter section is chamfered. In one embodiment, the device further includes a metal hypotube surrounding the outer surface of the first catheter portion just proximal to the curved distal end.

[0012] In one embodiment, the device may further include a polymer having a first diameter surrounding an outer surface of the proximal end of the first catheter section and a second diameter surrounding an outer surface of the distal end of the second catheter section, the second diameter being greater than the first diameter. [Brief description of the drawings]

[0013] [Figure 1] 1 illustrates an endoscopic access assembly for use in an EUS-guided procedure. [Diagram 2] 2 illustrates a distal end of a catheter of the endoscopic access assembly of FIG. 1. [Diagram 3] 3 shows a cross-sectional view of the catheter of FIG. 2. [Figure 4] 1 shows a catheter with an echogenic material on the exterior surface of a J-tip. [Diagram 5] 1 shows a catheter having a polymeric portion with a varying outer diameter. [Figure 6] A catheter with an extended hypotube is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention may be further understood with reference to the following description and the accompanying drawings, in which like elements are referred to by the same reference numerals. Exemplary embodiments are described for an endoscopic catheter device, in particular a microcatheter for use during EUS-guided procedures, such as pancreaticobiliary access procedures. The microcatheter has high column strength for smooth puncture when used with a sharp puncture tip (needle instrument) extending from the catheter lumen. Some embodiments are electrically insulating and heat resistant for electrosurgical dilation. Each of the described embodiments may have echogenic material added to improve visibility of the device under ultrasound guidance during the procedure.

[0015] FIG. 1 illustrates an endoscopic access assembly 100 for use during an EUS-guided procedure, according to an exemplary embodiment. The endoscopic access assembly 100 has a microcatheter 200, which is described in more detail below with respect to FIG. 3. The microcatheter 200 has a flexible tip 202. In an exemplary embodiment, the tip 202 may be configured to assume a curved shape (in an unstressed state), such as a J-shaped tip, as shown in FIG. 2. The curved shape may be a circular arc, a J-shape, or other shape. In an exemplary embodiment, the curved shape is a J-shape.

[0016] The microcatheter 200 further includes an outer support tube 210, as described in more detail below. In FIG. 1, a piercing element with a rigid needle-like tip 102 extends through the lumen and out of the tip 202 of the microcatheter 200. The needle 102 is generally straight in an unstressed state such that when the needle 102 is advanced through the lumen of the microcatheter 200 to the distal end of the tip 202, the tip 202 straightens out. In this straight configuration, i.e., with the needle 102 extending out of the distal end of the J-tip 202 (but prior to extending the needle 102 and tip 202 distal to the electrosurgical sheath 104), the combined needle / J-tip is advanced to a target location within the body (e.g., through an endoscope). The user may then pierce the anatomical target site to a predetermined depth with the needle instrument 102 while advancing the distal end 202 with the needle instrument 102 such that the tip 202 follows the needle instrument 102 through the tissue to the target location (e.g., through the wall of the small intestine and into the target bile duct). When the tip 202 is at the desired location within the bile duct, the needle instrument 102 is withdrawn from the tip 202, allowing the tip 202 to return to its curved shape. The tip 202 may then be rotated in the desired direction such that the distal hook of the tip 202 points the distal opening of the tip 202 in the direction in which the guidewire should be advanced into the bile duct.

[0017] A guidewire is then inserted into the microcatheter 200 and tip 202 and extended from the tip 202, and moved further into the bile duct until a desired length of the guidewire is received within the bile duct. Once the guidewire is positioned as desired, a flexible electrosurgical sheath 104 with an electrosurgical tip 106 is advanced over the catheter 200 and tip 202, and an RF current is applied from the electrosurgical tip 106 through the tissue to expand the access hole(s) created by the needle instrument 102 and tip 202. This ensures the integrity of these openings, after which the catheter 200 may be withdrawn from the body, leaving the guidewire in place within the bile duct. A stent or other therapeutic and / or diagnostic device may then be inserted over the guidewire through the access hole to a target site within the bile duct, as will be appreciated by those skilled in the art.

[0018] 3 shows a cross-section of catheter 200 in greater detail. Catheter 200 exhibits increased column strength based in part on the construction of outer support tube 210 and metal hypotube section 206, which are engineered for strength and flexibility, as described in more detail below. Catheter 200 also exhibits increased heat resistance, radiopacity, rotational control, water tightness, and flexibility.

[0019] The catheter 200 comprises a two-component catheter shaft having a distal braided polymer section 204 that includes a tip 202, with the proximal end of the polymer section 204 butting against a hypotube 206 proximal to the polymer section 204. The proximal end of the polymer section 204 and the distal end of the hypotube 206 butt at a butt junction 208. An outer support tube 210 is provided on the outer diameter of both the polymer section 204 and the hypotube 206, with a portion of the support tube 210 covering and supporting the junction 208 between the tube sections. The outer support tube 210 may extend the entire length of the catheter 200.

[0020] As will be appreciated by those skilled in the art, the polymer used for the braided polymer section 204 is selected to have a relatively high melting temperature (to prevent melting or deformation during electrosurgical expansion), shape memory (to allow the J-tip to return to its natural curved shape), and good dielectric strength (to electrically insulate the internal braid of the exposed tip). The polymer may be, for example, Alniter®, Pebax®, nylon, polyurethane, etc. One polymer may be better suited for high temperature applications, while another polymer may be better suited for low temperature applications. The braid within the polymer may be a round wire or ribbon made from fine stainless steel, steel, Nitinol, a more radiopaque material such as tungsten or platinum, or other metal. The braid may also include a high strength non-metallic braided reinforcement material such as liquid crystal polymer (LCP), PEEK, etc. The braided polymer may have a thin innermost layer. The innermost layer may be made, for example, of PTFE, FEP, HDPE, or other polymers that provide a braided surface and have lubricious additives to reduce friction, thereby reducing the force required to remove the needle device and / or pass the guidewire.

[0021] The tip 202 of the polymer portion 204 in this embodiment may be set into a J-shape using heat. As will be appreciated by one of ordinary skill in the art, the curved shape allows for the insertion of a guidewire into a target lumen (e.g., a bile duct) in a desired direction once the J-shaped tip 202 has entered the target anatomy, by rotating the J-shaped tip 202 to orient the distal opening of the lumen of the tip 202 in the desired direction. The braid provides durability, kink resistance, torque transmission, and tensile strength.

[0022] In addition, the distal end of the braided polymer section 204 of the tapered tip 202 can be beveled or tapered to reduce the force required to penetrate the target tissue upon initial puncture. The tip 202 can have a short, non-braided section at its most distal end to allow for tapering. The non-braided section can be, for example, a different material suitable for withstanding compressive forces upon tip entry, such as a harder material such as Vestamid nylon. The tip 202 can further have a radiopaque (RO) marker 214 at the distal end of the braid to help terminate the braid and / or to help provide radiopacity (e.g., to more easily visualize the marker 214, and thus the tip 202, via x-ray).

[0023] The metal hypotube 206 may be made of, for example, Nitinol to provide, for example, flexibility, column strength, and torque transmission. As will be appreciated by one of ordinary skill in the art, the distal end of the hypotube 206 (adjacent the polymer portion 204) may be chamfered on its inner diameter to prevent the guidewire from skiving along the inner edge.

[0024] The outer support tube 210 in this embodiment may be laser cut steel to provide flexibility, although other means of providing flexibility to the support tube 210, such as mechanical cutting or coiling, may be used. The steel material for the support tube 210 is less likely to crack than Nitinol and provides improved durability. The outer support tube 210 may have a short section that is not laser cut and is positioned at the junction 208 to prevent bending at the junction 208. Such bending may also lead to skiving of the guidewire at the butt junction 208 between the polymer 204 and the hypotube 206. To further prevent bending, the junction 208 between the polymer 204 and the hypotube 206 may be set sufficiently proximal from the distal tip such that the junction 208 does not enter the target anatomy through the tissue opening so that it may always be supported by the electrosurgical sheath 104.

[0025] The support tube 210 is secured to the outer diameter of the proximal end of the polymer 204 and the distal end of the hypotube 206, providing additional column strength, kink resistance, torsional stiffness and twist resistance to the polymer portion 204. The support tube 210 may be secured to the polymer 204 and the hypotube 206, for example, via an adhesive. It may also provide a chamfer or taper at the distal end of the hypotube 206 for smoother passage into tissue upon initial penetration using a needle instrument. The support tube 210 is covered with a thin layer of electrical insulator 212 to prevent burning of non-target tissue adjacent to the support tube 210 as the electrosurgical dilator tip 106 is advanced over the support tube 210.

[0026] In an alternative embodiment, the catheter 200 may form part of a cold device that provides puncture and directional guidewire access rather than cauterization or electrosurgical dilation. In this embodiment, the microcatheter does not need to be heat resistant or electrically insulated. Thus, the braided polymer can be made of Anitel®, Pebax®, PEEK, or another material. In this embodiment, electrical insulation is not required. The cold device may be used, for example, in a rendezvous EUS access procedure where a guidewire is fed into a duct and out of the papilla. If used in a transmural stent procedure, an exchange may be required to introduce an additional dilation tool, or a taper may be added to the electrosurgical tip 106 for cryo-dilation.

[0027] In yet another embodiment, the tip 202 of the catheter 200 is made long and flexible enough to be advanced through the duct to or through the stricture. As will be appreciated by those skilled in the art, having the tip 202 adjacent to the stricture provides additional support and ease of use when advancing the guidewire through the stricture during a rendezvous procedure. In some procedures, a stent may be placed over the guidewire. The laser cut steel design provides additional flexibility for passing through the pancreaticobiliary tree. Permanent shape changes during passage of the microcatheter 200 through the duct are acceptable, as shape changes are only detrimental to rotation and puncture, which are already completed at this point during use of the disposable device.

[0028] The exemplary embodiments also describe a microcatheter with added echogenic material for improved ultrasound viewing during the procedure. Echogenic material can be added to any of the embodiments described herein.

[0029] FIG. 4 shows a catheter 300 with an echogenic material 302 on the outer surface of the J-tip. The echogenic material, in this embodiment, can be a coating of hard echogenic particles suspended in a soft acoustically transparent material. Alternatively, the echogenic material can be a coiled or braided wire or polymer that covers the J-tip. The wire can be, for example, Nitinol, steel, tungsten, or other material that can be echogenic and at the same time radiopaque to enhance the radiopacity of the catheter 300. The wire can be, for example, round or ribbon-shaped with a diameter of about 0.1 / 1000 to about 5 / 1000 inches (about 2.54 / 1000 millimeters to about 127 / 1000 millimeters). If the echogenic material 302 is a wire or coil on the tip surface, an extended electrical insulator 304 can cover both the outer support tube and the echogenic material 302. However, if the catheter 300 is a cold device, electrical insulation would not be required.

[0030] Exemplary embodiments also describe a microcatheter that has a relatively small outer diameter despite including a laser cut support tube thereon, which may be desirable for physicians as a microcatheter with a reduced outer diameter may reduce the size of the puncture hole created in the tissue.

[0031] 5 shows a catheter 400 with a polymeric section 402 having a varying outer diameter. The catheter 400 has a larger outer diameter at a curved distal end comparable to previously described embodiments, and a smaller outer diameter at a proximal end surrounded by an outer support tube 408. The outer support tube 408 may have a thickness that substantially bridges the difference between the diameter of the curved distal end and the smaller proximal end. The outer support tube 408 gives the catheter 400 a substantially uniform outer diameter from the support tube section to the distal tip, although this uniform diameter is not required.

[0032] The hypotube 404 has a cross-sectional area generally similar to that of the reduced diameter proximal end of the polymeric portion 402, which is joined to the polymeric portion at junction 406, as in the previously described embodiments. The support tube 408 protects the junction 406 in a manner similar to that described with respect to the previously described embodiments. The reduced cross-sectional area allows for more precise puncture of the anatomical structure. The braided wires in the polymeric portion 402 may be partially exposed at the proximal end of the polymeric portion 402. These exposed braided wires are covered by the support tube 408 and / or electrical insulation 412. The catheter 400 may also include an echogenic material 410 covered by electrical insulation 412 for electrosurgical dilation applications.

[0033] In another embodiment, the inner and outer diameters of the polymer portion and the hypotube may not match exactly. When such an arrangement with mismatched inner diameters is used, the smaller diameter portion may be chamfered or tapered to prevent skiving of items such as guidewires. Alternatively, if the outer diameters are mismatched, skiving may be prevented by layering another material over the polymer or hypotube (whichever is smaller) to fill the gap between them and the support tube. This material may be, for example, heat shrink.

[0034] In yet another embodiment, the outer support tube may be omitted from the design and replaced with a hypotube. This embodiment may be desirable for applications where a less flexible or smaller device is acceptable, such as urological applications. When used in applications with less tortuous pathways or where the device is smaller overall, it may be easier to rotate without excessive whipping.

[0035] FIG. 6 shows a catheter 500 with an expanded hypotube 504. The catheter 500 includes a polymer section 502. Similar to FIG. 4, the polymer section 502 has a larger outer diameter at the curved distal end and a smaller outer diameter at the proximal end. However, rather than being surrounded by an outer support tube, the smaller diameter proximal end is surrounded by the hypotube 504. Alternatively, as shown in FIG. 4, the polymer may have a constant outer diameter. In this embodiment, the polymer section 502 extends proximally the entire length of the catheter at the smaller diameter, and the hypotube 504 provides support along the length of the catheter until the junction 506 where the hypotube 504 terminates. The polymer 502 and hypotube 504 may be bonded using adhesive, polymer reflow, or other means. The junction 506 may be located further distally than in previous embodiments. For example, the hypotube 504 may extend to the puncture site.

[0036] In another embodiment, the metal hypotube may be omitted from the design. In this embodiment, the polymer extends the length of the catheter, and the outer support tube extends the longer proximally. This embodiment may be particularly suitable for applications where the device may be short in length, such as urological or respiratory applications. In these cases, the axial compression of the laser cut support tube and polymer is increased over the shorter overall length, resulting in less overall axial compression upon puncture.

[0037] (Additional Note) As a preferred embodiment, the technical ideas that can be understood from the above embodiment will be described below. [Item 1] An apparatus comprising: a catheter including a lumen therethrough, the catheter sized and shaped to extend through an endoscope shaft to a target tissue within a living body, the lumen sized and shaped to receive a puncture device therethrough, the catheter including a first catheter portion distal to a second catheter portion, the first catheter portion and the second catheter portion being formed from different materials, the first catheter portion having a flexible curved distal end; a support tube secured around an outer surface of the proximal end of the first catheter section and an outer surface of the distal end of the second catheter section, wherein an outer diameter of a portion of the catheter extending distally of the distal end of the support tube is approximately the same as an outer diameter of the support tube. [Item 2] 2. The device of claim 1, wherein the first catheter portion is formed of a braided polymer and the second catheter portion is formed of Nitinol. [Item 3] Item 1, the device according to The apparatus further comprising an electrically insulating layer surrounding the support tube. [Item 4] 4. The device according to any one of items 1 to 3, wherein the first catheter portion and the second catheter portion are butted together at a butt joint and joined to the support tube. [Item 5] The device according to any one of items 1 to 4, The device further comprises an echogenic material on the flexible distal end or on the support tube, or on the flexible distal end and on the support tube. [Item 6] 6. The device according to claim 5, wherein the echogenic material is a coating comprising particles suspended in an acoustically transparent material. [Item 7] 6. The device of claim 5, wherein the echogenic material is a coiled or braided wire or polymer overlying the distal end. [Item 8] The device according to any one of items 1 to 7, The device further comprises a puncture device sized and shaped to pass through the lumen of the catheter and extend distally from the curved distal end, the puncture device straightening the curved distal end as the puncture device extends through the curved distal end such that when the puncture device punctures an access hole into a target tissue, the straightened distal end follows the puncture device into the access hole. [Item 9] The device according to any one of items 1 to 8, The apparatus further comprises an electrosurgical sheath slidable longitudinally along the exterior of the catheter and support tube, the electrosurgical sheath having an electrosurgical tip for electrosurgically widening an access hole when the electrosurgical sheath is slid over the curved distal end and an electric current is applied. [Item 10] 10. The device according to any one of claims 1 to 9, wherein a proximal end of the first catheter portion has a reduced outer diameter relative to an outer diameter of a distal end of the first catheter portion. [Item 11] 11. The device according to claim 10, wherein the second catheter section has an outer diameter approximately equal to the reduced outer diameter of the proximal end of the first catheter section. [Item 12] The device according to any one of items 1 to 11, and wherein an outer diameter of the proximal end of the first catheter portion and an outer diameter of the distal end of the second catheter portion are of different dimensions, and wherein a polymer surrounds one of an outer surface of the proximal end of the first catheter portion and an outer surface of the distal end of the second catheter portion. [Item 13] 13. The device according to any one of items 1 to 12, wherein an edge of one of an inner surface of the proximal end of the first catheter portion and an inner surface of the distal end of the second catheter portion is chamfered. [Item 14] The device according to any one of items 1 to 13, The device, wherein the support tube is a metal hypotube that surrounds the exterior surface of the first catheter section just proximal to the curved distal end. Those skilled in the art will appreciate that the above embodiments may be modified without departing from the concept of the present invention. It will also be appreciated that structural features and methods associated with one of the embodiments may be incorporated into other embodiments. Therefore, it will be appreciated that the present invention is not limited to the specific embodiments described, and that modifications are also included within the scope of the present invention as defined by the appended claims.

Claims

[Claim 1] An apparatus comprising: The apparatus comprises a catheter including a lumen therethrough, the catheter sized and shaped to extend through an endoscope shaft to a target tissue within a living body, the lumen sized and shaped to receive a puncture device therethrough, the catheter including a first catheter section distal to a second catheter section, the first catheter section being formed as a braided polymer tube and the second catheter section being formed of metal, the first catheter section having a flexible curved distal end; the apparatus includes a support tube secured about an outer surface of the proximal end of the first catheter portion and an outer surface of the distal end of the second catheter portion; The apparatus further comprises an electrosurgical sheath longitudinally slidable along the exterior of the catheter, the electrosurgical sheath having an electrosurgical tip for electrosurgically widening an access hole when the electrosurgical sheath slides over the flexible curved distal end and an electric current is applied.

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