Catheter braided wire having variable cross-sectional shape

Abstract

To provide a system capable of providing smooth transition to a relatively flexible distal part from a relatively rigid proximal part of a catheter while maintaining rigidity in an axial direction, a device, and a method.SOLUTION: A catheter braid includes a wire segment 108 having a variety of cross-sectional shapes. A wire segment in a proximal part of the braid 100 can have a virtually rectangular cross-sectional shape, while a wire segment in a distal part of the braid can have a virtually circular cross-sectional shape. The cross-sectional shape can gradually transit from a rectangle to a circle along length of the braid. The catheter braid can include a wire segment having an outer core and an inner core. The inner core in a proximal section of the braid can have a virtually rectangular cross-sectional shape; the inner core at a distal part of the braid can have a virtually circular cross-sectional shape.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Patent Application No. 63 / 110,613, filed November 6, 2020, the entire contents and abstract of which are incorporated herein by reference as if fully set forth below.

[0002] FIELD OF THE INVENTION FIELD OF THE INVENTION The present disclosure relates generally to devices and methods for accessing blood vessels during intravascular medical care. More particularly, the present disclosure relates to catheters having improved flexibility while maintaining axial stiffness. [Background technology]

[0003] Catheters serve a wide variety of functions in intravascular medical procedures. Catheters are typically thin tubes made of medical-grade materials that can be inserted into the body and used to deliver drugs or other devices, perform surgical procedures, remove blockages from blood vessels, and for a variety of other purposes. By varying the material or adjusting the way the catheter is manufactured, it is possible to tailor different sections of the catheter for specific uses.

[0004] Several designs and methods have been proposed for navigating a catheter to a target site. In one method, the catheter is fitted over a guidewire used to access the target site and slid along the guidewire. However, thin guidewires almost always have a greater reach and distal flexibility than catheter tubing. Newer designs have been proposed that utilize various methods for varying the stiffness between the proximal and distal sections of the catheter, such as polymer tubing sets, often with braids or windings that include wires or bands of other materials for reinforcement. Current designs may include a softer, more flexible distal section of the catheter while increasing stiffness toward the proximal section. Such designs can facilitate successful use in vascular applications by providing a smooth transition from the softer, more flexible distal section to the stiffer proximal section. However, some existing designs lack the strength useful for some medical procedures or include abrupt stiffness or geometric changes that can impair compliance, introduce significant stress concentrations, and potentially increase the likelihood of device kinking or buckling. As a result, some designs often have unacceptable levels of pushability, compliance, and twistability for widespread adoption among physicians. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, there is a need for systems, devices, and methods that can provide a smooth transition from a relatively stiff proximal section to a relatively flexible distal section of a catheter while maintaining axial stiffness. [Means for solving the problem]

[0006] Generally, an object of the present invention is to provide a catheter braid including wire segments having various cross-sectional shapes, thereby providing a relatively soft and flexible catheter shaft at the distal portion of the braid and a relatively stiff catheter shaft at the proximal portion of the braid. In one embodiment, the wire segments at the proximal portion can have a substantially rectangular cross-sectional shape, and the wire segments at the distal portion can have a substantially circular cross-sectional shape. The cross-sectional shapes of the wire segments can gradually transition from the rectangular cross-sectional shape to the circular cross-sectional shape, thereby minimizing the possibility of kinking. In a further embodiment, the wire segments can have an outer core and an inner core. The inner core at the proximal portion of the braid can have a substantially rectangular cross-sectional shape, and the inner core at the distal portion of the braid can have a substantially circular cross-sectional shape. The cross-sectional shape of the inner core can gradually transition from rectangular to circular, providing a smooth transition. The composition of the outer shell can be different from the composition of the inner core, and the composition of the inner core can change as the wire segment extends from the proximal portion to the distal portion. By varying the cross-sectional shape and / or composition of the inner core, the catheter can smoothly transition from a hard, rigid shaft in the proximal section to a soft, flexible shaft in the distal section.

[0007] An exemplary catheter braid can include a proximal portion having a proximal end, a distal portion having a distal end, and a length extending between the proximal and distal ends. The catheter braid can include multiple wire segments, each wire segment including an outer shell and an inner core. The outer shell can have a first material composition. The inner core can extend through the outer shell and can have a second material composition different from the first material composition over at least a portion of the length of the catheter braid. The inner core can have a first cross-sectional shape near the proximal end and a second cross-sectional shape near the distal end. The first cross-sectional shape can transition to the second cross-sectional shape along the length of the catheter braid.

[0008] A proximal portion of the catheter braid can have a first number of picks per inch and a distal portion of the catheter braid can have a second number of picks per inch. The first number of picks per inch can be less than the second number of picks per inch.

[0009] The first number of picks per inch can be from about 20 to about 45. The second number of picks per inch can be from about 120 to about 200.

[0010] The first cross-sectional shape may be substantially rectangular and the second cross-sectional shape may be substantially circular.

[0011] The catheter braid can further include a transition portion extending over at least a portion of the proximal portion and over at least a portion of the distal portion. The transition portion can have a variable cross-sectional shape that can gradually transition from being substantially rectangular near the proximal portion to being substantially circular near the distal portion.

[0012] The second material composition can include a first metal in the proximal portion, a second metal in the transition portion, and a third metal in the distal portion. The first metal can have a higher stiffness than the second and third metals. The second metal can have a higher stiffness than the third metal.

[0013] The inner core may be hollow at the distal end of the distal portion.

[0014] The first cross-sectional shape may be substantially rectangular, and the second cross-sectional shape may be substantially rectangular.

[0015] The inner core can include a first metal at a proximal portion and a second metal at a distal portion. The first metal can have a greater stiffness than the second metal.

[0016] The outer shell may include an upper semi-cylinder relative to the longitudinal axis and a lower semi-cylinder relative to the longitudinal axis.

[0017] The inner core can include a first metal, the upper semi-cylinder can include a second metal, and the lower semi-cylinder can include a third metal, which can have a higher density than the first metal, and both the second metal and the first metal can have higher densities than the second metal.

[0018] The upper half-cylinder may include one or more air channels.

[0019] Another exemplary catheter may include a tubular body, a first braid, and a second braid. The tubular body may include a proximal portion and a distal portion. The first braid may be disposed over the proximal portion. The first braid may include a first plurality of wire segments. Each wire segment may include a first outer shell and a first inner core having a substantially rectangular cross-sectional shape. The second braid may be disposed over the distal portion. The second braid may include a second plurality of wire segments. Each wire segment may include a second outer shell and a second inner core having a substantially circular cross-sectional shape.

[0020] The first braid can have a first number of picks per inch and the second braid can have a second number of picks per inch. The second number of picks per inch can be greater than the first number of picks per inch.

[0021] The inner core of each wire segment of the second plurality of wire segments may be hollow near the distal end of the distal portion.

[0022] Another exemplary catheter braid disposed along the length of a catheter can include a proximal portion and a distal portion. The proximal portion can include wire segments having a first cross-sectional shape that is substantially rectangular. The distal portion can include wire segments having a second cross-sectional shape that is substantially circular.

[0023] The proximal portion may have a lower number of picks per inch than the distal portion.

[0024] The catheter braid can further include a transition section disposed between the proximal and distal sections, the transition section having a higher number of picks per inch than the proximal section and a lower number of picks per inch than the distal section.

[0025] The transition section can extend from about 5 to about 15 centimeters in length and can have a variable cross-section that can be substantially rectangular near the proximal section and substantially circular near the distal section.

[0026] The proximal portion can have from about 20 to about 50 picks per inch, the transition portion can have from about 50 to about 90 picks per inch, and the distal portion can have from about 110 to about 200 picks per inch.

[0027] The features of the exemplary catheters described above may be combined in accordance with the teachings herein and / or in any manner apparent to one of ordinary skill in the art. [Brief explanation of the drawings]

[0028] The above and further aspects of the present invention will be further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in the various drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. The figures depict one or more implementations of devices of the present invention, by way of example only, and not by way of limitation. [Figure 1A] 1 is a diagram of an exemplary braided catheter, in accordance with an aspect of the present invention. [Figure 1B] 1B is a diagram of an exemplary wire segment of the braid of FIG. 1A, according to an embodiment of the present invention. [Figure 1C]1C is a cross-sectional view of the wire segment of FIG. 1B at a proximal portion of an exemplary braid, according to an embodiment of the present invention. [Figure 1D] 1C is a cross-sectional view of the wire segment of FIG. 1B at a distal portion of an exemplary braid, according to an embodiment of the present invention. [Figure 2A] 10A-10C are diagrams of catheters including alternative exemplary braids, in accordance with aspects of the present invention. [Figure 2B] 2B is a cross-sectional view of a wire segment in a proximal portion of the exemplary braid of FIG. 2A, according to an embodiment of the present invention. [Figure 2C] 2B is a cross-sectional view of a wire segment at a transition portion of the exemplary braid of FIG. 2A, according to an embodiment of the present invention. [Figure 2D] 2B is a cross-sectional view of a wire segment in a distal portion of the exemplary braid of FIG. 2A, according to an embodiment of the present invention. [Figure 3A] 2B is a cross-sectional view of an alternative exemplary wire segment of the braid of FIG. 2A, according to an embodiment of the present invention. [Figure 3B] 2B is a cross-sectional view of an alternative exemplary wire segment of the braid of FIG. 2A, according to an embodiment of the present invention. [Figure 4A] 2B is a cross-sectional view of an alternative exemplary wire segment of the braid of FIG. 2A, according to an embodiment of the present invention. [Figure 4B] 2B is a cross-sectional view of an alternative exemplary wire segment of the braid of FIG. 2A, according to an embodiment of the present invention. [Figure 4C] 2B is a cross-sectional view of an alternative exemplary wire segment of the braid of FIG. 2A, according to an embodiment of the present invention. [Figure 5A] FIG. 1 is a diagram of a catheter including a first braid and a second braid, according to an embodiment of the present invention. [Figure 5B] 5B is a cross-sectional view of a wire segment of the first braid of FIG. 5A according to an embodiment of the present invention. [Figure 5C] FIG. 5B is a cross-sectional view of a wire segment of the second braid of FIG. 5A, according to an embodiment of the present invention. [Figure 5D] FIG. 5B is a cross-sectional view of a wire segment of the second braid of FIG. 5A, according to an embodiment of the present invention. [Figure 6]FIG. 1 is a flow diagram outlining an exemplary method for manufacturing an exemplary braid. [Figure 7] FIG. 10 is a flow diagram outlining an additional or alternative method of manufacturing an exemplary braid. DETAILED DESCRIPTION OF THE INVENTION

[0029] The disclosed technology can include a catheter braid including wire segments having various cross-sectional shapes along the length of the braid, providing a relatively soft, flexible shaft in the distal section, a relatively stiff shaft in the proximal section, and a gradual transition between the flexible and stiff shafts. In one embodiment, the wire segments in the proximal section of the braid can have a substantially rectangular cross-sectional shape, thereby providing a stiff proximal shaft and maximizing column strength. The cross-sectional shapes of the wire segments can gradually transition from rectangular to circular to provide increased radial flexibility in the distal section. The gradual transition from one cross-sectional shape to a different cross-sectional shape can reduce the likelihood of kinking. In a further embodiment, the wire segments can have an outer core and an inner core. The inner core in the proximal section of the braid can have a substantially rectangular cross-sectional shape, and the inner core in the distal section of the braid can have a substantially circular cross-sectional shape. The cross-sectional shape of the inner core can gradually transition from rectangular to circular to provide a smooth transition. The composition of the outer shell may be different from the composition of the inner core, and the composition of the inner core may vary as the wire segment extends from the proximal to the distal portion. By varying the cross-sectional shape and / or composition of the inner core, the catheter can smoothly transition from a hard, rigid shaft in the proximal portion to a soft, flexible shaft in the distal portion without sacrificing the pushing efficiency of the proximal shaft.

[0030] While exemplary embodiments of the disclosed technology are described in detail herein, it should be understood that other embodiments are contemplated. Accordingly, it is not intended that the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings be used to limit the scope of the disclosed technology. The disclosed technology is capable of other embodiments and of being practiced or carried out in various ways.

[0031] It should also be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. "Comprising" or "containing" or "including" means that at least the referenced compound, element, particle, or method step is present in a composition or article or method, but does not exclude the presence of other compounds, materials, particles, or method steps, even if such other compounds, materials, particles, or method steps have the same function as the referenced one.

[0032] In describing the exemplary embodiments, technical terminology is utilized for clarity. Each term is intended to have its broadest meaning as understood by one of ordinary skill in the art and is intended to include all technical equivalents that operate in a similar manner to accomplish a similar purpose. It should also be understood that a reference to one or more steps of a method does not preclude the presence of additional or intervening method steps between those explicitly identified steps. Method steps may be performed in an order different from that set forth herein without departing from the scope of the disclosed technology. Similarly, it should also be understood that a reference to one or more components in a device or system does not preclude the presence of additional or intervening components between those explicitly identified components.

[0033] As discussed herein, the vasculature may be that of any "subject" or "patient," including any human or animal. It should be understood that the animal may be of any of a variety of relevant types, including, but not limited to, mammals, veterinary animals, livestock animals, or pet animals. By way of example, the animal may be a laboratory animal (e.g., rats, dogs, pigs, monkeys, etc.) specifically selected to have certain characteristics similar to humans. It should be understood that the subject may, for example, be any relevant human patient.

[0034] As discussed herein, the term "about" or "approximately" used in connection with any numerical value or range of numerical values ​​indicates a suitable dimensional tolerance that enables a portion of a component or a collection of components to function in accordance with its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value, for example, "about 90%" may refer to a range of values ​​of 71% to 99%.

[0035] As used herein, the term "substantially" when describing geometric characteristics refers to suitable dimensional tolerances that allow a portion of a collection of components to function for its intended purpose, and the geometric characteristics approximate the exact shape being described despite deviations from the exact shape. For example, a "substantially" rectangular shape may deviate from an exact rectangular shape, e.g., rounded corners, sides that are not exactly parallel, and / or corners that are not exactly 90°, while the "substantially" rectangular shape achieves a similar function as that of an exact rectangular shape. A "substantially" rectangular shape may be close enough to an exact rectangular shape that "rectangle" is a reasonably appropriate description in the plain and ordinary sense of the word. In a rectangle with a semicircle on each short side, sometimes referred to as a "stadium" shape, "stadium" is a less common shape descriptor than "rectangle," and a feature with a "stadium" shape can be considered "substantially" rectangular if it retains its function when substituted for a "rectangle" shape.

[0036] The figures show generally hollow or tubular structures in accordance with the present invention. As used herein, the terms "tubular" and "pipe / tube" are intended to be broadly construed and are not limited to structures that are right cylindrical or strictly circular in cross section, or to structures that are uniform in cross section along their entire length. For example, tubular structures or tubular systems are generally illustrated as substantially right cylindrical structures. However, tubular systems may have tapered or curved outer surfaces without departing from the scope of the present invention.

[0037] Referring now to the figures, FIG. 1A shows a catheter 10 having a braid 100. The catheter 10 can include an elongated tubular body 120. The tubular body 120 can be made from various medical grade polymers, such as PTFE, polyether block amide (Pebax®), or nylon. The catheter 10 can include a braid 100 disposed over the tubular body 120. The braid 100 can extend over a length L. The braid 100 can extend a length L that is substantially the same as the length of the tubular body 120. Alternatively, the braid 100 can extend over a portion of the tubular body 120. The braid 100 can be a single continuous braid extending over the tubular body 120 and can have a proximal portion 102, a transition portion 104, and a distal portion 106. By way of example, the proximal portion 102 can extend from about 45 centimeters to about 55 centimeters, the transition portion 104 can extend from about 5 centimeters to about 15 centimeters, and the distal portion 106 can extend from about 25 centimeters to about 35 centimeters.

[0038] The braid 100 can be made from multiple wire segments 108. The wire segments 108 can be made from a variety of metallic materials. By way of example, the wire segments 108 can be made from stainless steel, cobalt chromium, molybdenum and niobium alloys, or any other hard metal alloy. The braid 100 can have a varying number of picks per inch along its length L. The proximal portion 102 of the braid 100 can have a lower number of picks per inch compared to the transition portion 104 and the distal portion 106, thereby aiding in axial stiffness. By way of example, the proximal portion 102 can have a number of picks per inch of about 20 to about 50. To provide increased radial flexibility near the distal end of the catheter 10, the number of picks per inch of the braid 100 can be increased within the transition portion 104 and the distal portion 106. The transition portion 104 can have a number of picks per inch of about 50 to about 90. The distal portion 106 can have a picks per inch of about 110 to about 200, thereby providing a flexible catheter shaft capable of effectively navigating tortuous vasculature.

[0039] As discussed further herein, each wire segment of the plurality of wire segments 108 can have a first cross-sectional shape at the proximal portion 102 and a second cross-sectional shape at the distal portion 106. The transition portion 104 can facilitate a gradual transition of the wire segment 108 from the first cross-sectional shape to the second cross-sectional shape.

[0040] The catheter 10 may further include a marker band 110 positioned near the distal end 122 of the tubular body 120. The marker band 110 may be secured to the tubular body 120 to provide radiopacity, thereby allowing a user to accurately position the catheter 10 within the patient's vasculature. By way of example, the marker band 110 may be a platinum marker band.

[0041] A polymer jacket 124a can be disposed around the braid 100. A first polymer jacket 124a can be disposed around the proximal portion 102 of the braid 100. In some cases, the first polymer jacket 124a can be disposed around the proximal portion 102 and at least a portion of the transition portion 104. The first polymer jacket 124a can have a durometer of about 60 to about 80. A second polymer jacket 124b can be disposed around at least a portion of the transition portion 104 and the distal portion 106 of the braid 100. In some cases, the second polymer jacket 124b can extend to the tubular body distal end 122, thereby covering the marker band 110. The second polymer jacket 124b can have a durometer of about 40 to about 80.

[0042] FIG. 1B illustrates a wire segment 108 of the braid 100 shown in FIG. 1A. FIGS. 1C and 1D illustrate cross sections of respective wire segment portions 108a, 108c of the wire segment 108 as shown in FIG. 1B. Referring collectively to FIGS. 1A-1D, the wire segments 108 of the braid 100 can have various cross sections as the braid 100 extends from the proximal portion 102 to its distal portion 106. As shown in FIGS. 1B and 1C, the proximal portion 102 can include a wire segment portion 108a having a substantially rectangular cross section. The wire segment portion 108a within the proximal portion 102 of the braid 100 can be designed to maximize its width 112. By way of example, the width 112 of the wire segment portion 108a in the proximal portion 102 can be approximately 0.25 millimeters (0.01 inches). By maximizing the width 112 of the wire segment portions 108a, the resulting braid 100 can substantially resemble a metal hypotube. The wire segment portions 108a can be further designed to have a height 110 of approximately 0.01 millimeters (0.0004 inches). Thus, the proximal portion 102 of the braid 100 can provide sufficient column strength and axial stiffness.

[0043] As shown in FIGS. 1B and 1D , the distal portion 106 can include a wire segment 108c having a substantially circular cross-section. By way of example, the wire segment 108c can have a diameter 114 of approximately 0.06 millimeters (0.0025 inches). Furthermore, if the wire segment 108c of the distal portion 106 is made of an alloy, including stainless steel and chromium alloys, cobalt-chromium alloys, and molybdenum and niobium alloys, the diameter 114 can be kept relatively small, allowing the overall inner diameter of the catheter 10 to be larger compared to some commercially available catheters. This can allow for an increased lumen for translating an auxiliary catheter through the catheter 10, if needed, or for aspiration. The circular cross-section of the wire segment 108c can provide increased flexibility compared to the wire segment 108a in the proximal portion 102. Having a flexible catheter tip can facilitate navigating the distal end of the catheter 10 through tortuous vasculature.

[0044] 1B, the transition portion 104 of the braid 100 can include wire segment portions 108b having various cross-sectional shapes. The wire segment portions 108b can have a substantially rectangular cross-sectional shape near the proximal portion 102 and can gradually transition to a substantially circular cross-sectional shape near the distal portion 106. The gradual transition from the rectangular cross-sectional shape of the wire segment portions 108a in the proximal portion 102 to the circular cross-sectional shape of the wire segment portions 108c in the distal portion 106 can reduce the likelihood of one or more kinks. The smooth transition can facilitate force transmission as the catheter 10 is pushed distally through the vasculature.

[0045] By varying the cross-sectional shape of the braid 100 (by varying the cross-sectional shape of the wires 108 of the braid 100) as the braid 100 extends along the tubular body 120 of the catheter 10, the proximal shaft of the catheter 10 can have the desired stiffness and column strength for sufficient navigation, thereby reducing the likelihood of injury during navigation, while the distal shaft of the catheter 10 can have the desired flexibility and trackability.

[0046] Figure 2A illustrates a catheter 10 including alternative exemplary braids 200, 300, 400. Figures 2A-2D illustrate an exemplary braid 200 including multiple wire segments 208. Figures 2A and 3A-3C illustrate an exemplary braid 300 including multiple wire segments 308. Figures 2A and 4A-4B illustrate an exemplary braid 400 including multiple wire segments 408. Thus, although the exemplary braids 200, 300, 400 may be similarly disposed over the tubular body 120 of the catheter 10, some properties of the multiple wire segments 208, 308, 408 may vary depending on the exemplary braid 200, 300, 400.

[0047] The catheter 10 may include a tubular body 120. The braid 200, 300, 400 may extend over a length L of the catheter 10. In some cases, the braid 200, 300, 400 may extend over a portion of the catheter 10. Alternatively, the braid 200, 300, 400 may extend over the entire length of the catheter 10. The braid 200, 300, 400 may have a proximal portion 202, 302, 402 having a proximal end 202 a, 302 a, 402 a and a distal portion 206, 306, 406 having a distal end 206 a, 306 a, 406 a. Specifically, the braid 200 may further include a transition portion 204 that may extend over at least a portion of the proximal portion 202 and over at least a portion of the distal portion 206.

[0048] The braid 200, 300, 400 can be made from multiple wire segments 208, 308, 408 and can have various picks per inch as the braid 200, 300, 400 extends along the length L of the catheter 10. The proximal portion 202, 302, 402 of the braid 200, 300, 400 can have a picks per inch of about 20 to about 45. The distal portion 206, 306, 406 of the braid 200, 300, 400 can have a picks per inch of about 120 to about 200.

[0049] 2B-2D show cross-sectional views of each wire segment portion 208a, 208b, 208c of each wire segment 208 of braid 100b. Wire segment 208 may be drawn filled tube (DFT), with each wire segment 208 having an outer shell 210 and an inner core 212. Outer shell 210 may have a material composition, and inner core 212 may have a material composition that is different from the material composition of outer core 212 over at least a portion of wire segment 208. As shown in FIG. 2D, portion 208c of wire segment 208 having inner core 212 with a circular cross-section allows wire segment 208 to bend and flex equally in all radial directions. 2B and 2C , for portions 208a, 208b of wire segment 208 having a non-circular inner core 212, the wire segment can bend or flex in any preferred direction as defined by the non-circular shape of inner core 212 while maintaining a circular outer profile. The first metal composition of outer shell 210 can remain the same as braid 100b and extend along the length L of braid 200. The second composition of inner core 212 can vary as braid 200 extends from proximal portion 202 to distal portion 206, such that the second composition can be different from the first composition along at least a portion of length L of braid 200. Inner core 212 can have various cross-sectional shapes as braid 100b extends over tubular body 120. By gradually varying the cross-sectional shape of the inner core 212 and / or varying the material composition of the inner core 212, the catheter 10 can have a relatively stiff proximal shaft and a relatively flexible distal shaft, thereby providing effective navigation through the vasculature.

[0050] FIG. 2B shows a cross-sectional view of the first wire segment portion 208a of the wire segment 208. The first wire segment portion 208a can be disposed over the proximal portion 202 of the braid 200. The first wire segment portion 208a can include an outer shell 210 and an inner core 212. The outer shell 210 can have a substantially circular cross-section. The outer shell 210 can have a diameter 214 of approximately 0.06 millimeters (0.0025 inches). Preferably, the outer shell 210 comprises stainless steel, and the composition of the inner core 212 in the proximal portion 202 of the wire segment 208 comprises a relatively stiff metal and / or combination of metals compared to the outer shell 210. By way of example, the inner core 212 of the first wire segment portion 208a can be made of cobalt chrome, martensitic steel, or chrome steel. Alternatively, the outer shell 210 can be stiffer than the inner core 212 in the proximal portion 202. The overall stiffness of each segment portion 208a, 208b, 208c of the wire segment 208 can be determined based on the relative cross-sectional area of ​​the outer shell 210 compared to the inner core 212, with the material encompassing the largest cross-sectional area having the greatest impact on the overall stiffness of the wire segment. In embodiments where the inner core 212 has a larger cross-sectional area compared to the outer shell 210, the shape and material properties of the inner core 212 can more significantly determine the overall material properties of the wire segment 208 than the outer shell 210. The relative stiffness of the outer shell 210 and inner core 212 can be based on the Young's modulus and / or ultimate tensile strength ("UTS") values ​​of the metal compositions of the outer shell 210 and inner core 212.

[0051] The inner core 212 can have a substantially rectangular cross-sectional shape. The inner core 212 has a length 218 similar to the diameter 214 and width 216 of the outer shell 210. By way of example, the inner core 212 can have a length 218 of approximately 0.05 millimeters (0.0018 inches) and a width 216 of approximately 0.01 millimeters (0.0003 inches). Similarly, the ratio of the inner core length 218 to the inner core width 216 can be approximately 6 to 1. By having the inner core 212 with a substantially rectangular cross-sectional shape and the circular outer shell 210 with a relatively stiff metal composition (e.g., having a Young's modulus and / or UTS substantially similar to or greater than that of the outer shell 210), the wire segment portion 208a can be a round wire, but can have properties and functionality similar to a flat wire. This allows the first wire segment portion 208a to provide increased axial stiffness and rigidity at the proximal end of the catheter 10 compared to a catheter having a fully round wire without an inner core 212.

[0052] FIG. 2C shows a cross-sectional view of the second wire segment portion 208b of the wire segment 208. The second wire segment portion 208b can be disposed above the transition portion 204 of the braid 200. The composition of the inner core 212 in the second wire segment portion 208b can be made of a second metal and / or combination of metals that is less stiff (e.g., has a lower Young's modulus and / or UTS value) than the first metal of the inner core 212 of the proximal portion, thereby increasing flexibility as the braid 100b extends along the length L of the catheter 10. The outer shell 210 can have a substantially circular cross-section with the same diameter 214 as the second wire segment portion 208a. The inner core 212 can have a variety of cross-sectional shapes. The inner core 212 can have a substantially rectangular cross-sectional shape near the proximal portion 202 and a substantially circular cross-sectional shape near the distal portion 206. As shown in FIG. 2C , the inner core 212 can have a substantially elongated, oval, or stadium-like shape approximately in the middle of the transition portion 204. The edge length 222 of the inner core 212 is approximately 0.02 millimeters (0.00065 inches). The width 224 of the inner core 212 can be approximately 0.03 millimeters (0.0012 inches). The gradual transition from the rectangular cross-sectional shape of the wire segment portion 208 a of the proximal portion 202 to the circular cross-sectional shape of the wire segment portion 208 c of the distal portion 206 can reduce the likelihood of kinking.

[0053] FIG. 2D shows a cross-sectional view of the third wire segment portion 208c of the wire segment 208. The third wire segment portion 208c can be disposed over the distal portion 206 of the braid 100b. The outer shell 210 can maintain a substantially circular cross-section having the same diameter 214 as the first and second wire segment portions 208a and 208b. The composition of the inner core 212 can be a third metal and / or combination of metals that is less stiff (e.g., has a lower Young's modulus and / or UTS value) than the second and first metals of the inner core 212 in the transition portion 204 and proximal portion 202, respectively. In some cases, the inner core 212 can be hollow or void, thereby providing increased flexibility of the catheter shaft in the distal portion 206. The inner core 212 can have a substantially circular cross-section. The diameter of the inner core 212 can be approximately 0.04 millimeters (0.0015 inches). The gradual transition from a relatively rigid first metal to a relatively flexible third metal in the proximal portion 202, or even a cavity or void, results in a catheter 10 that can have a relatively rigid proximal shaft that can become gradually more flexible in the distal direction.

[0054] Varying the cross-sectional shape of the inner core 212 along the proximal section 202, the transition section 204, and the distal section 206 of the braid 200 can provide the catheter 10 with sufficient axial stiffness at the proximal end of the catheter 10 and sufficient flexibility at the distal end of the catheter 10. This does not sacrifice column strength and axial stiffness to provide a flexible catheter tip capable of navigating tortuous vasculature. The gradual transition from a rectangular to a circular cross-sectional shape of the inner core 212 can further reduce the likelihood of kinking during navigation.

[0055] 3A and 3B illustrate alternative exemplary wire segments 308 of the braid 300. FIG. 3A illustrates a first wire segment portion 308a of the wire segment 308. The first wire segment portion 308a can be disposed on the proximal portion 302 of the braid 300. FIG. 3B illustrates a second wire segment portion 308b of the wire segment 308. The second wire segment portion 308b can be disposed on the distal portion 206 of the braid 300. The wire segment 308 can have an outer shell 310 and an inner core 312. As shown in FIGS. 2B-2D , the outer shell 310 can have a substantially circular cross-sectional shape. The inner core 312 can have a substantially rectangular cross-sectional shape at both the proximal portion 202 and the distal portion 206. Thus, the inner core 312 can have a substantially rectangular cross-sectional shape along the entire length L of the braid 300. The length 318a of the inner core 312 at the proximal portion 302 may be substantially equal to the length 318b of the inner core 312 at the distal portion 306. By way of example, the lengths 318a, 318b may be approximately 0.04 millimeters (0.0018 inches). Similarly, the width 316a of the inner core 312 at the proximal portion 202 may be substantially equal to the width 316b of the inner core 212 at the distal portion 206. By way of example, the widths 316a, 316b may be approximately 0.01 millimeters (0.0003 inches). In this configuration, the ratio of the inner core length 318 to the width 316 of the inner core 312 may be approximately 6 to 1.

[0056] 3A and 3B have a uniform rectangular cross-sectional shape, the inner core 312 of the first wire segment portion 308a in the proximal portion 302 of the braid 300 can include one or more metals, while the inner core 312 of the second wire segment portion 308b in the distal portion 306 of the braid 300 can include one or more different metals. The inner core 312 of the first wire segment portion 308a can include a stiffer metal or combination of metals, providing the catheter 10 with increased column strength compared to the inner core 312 of the second wire segment portion 308b. The second wire segment portion 308b can include a metal or combination of metals having a lower Young's modulus and / or ultimate tensile strength (“UTS”) than the metal or combination of metals of the first wire segment portion 308a. By way of example, the second wire segment portion 308b can comprise nitinol, titanium, austenitic steel, and / or stainless steel, while the first wire segment portion 308a can comprise martensitic steel, stainless steel, tantalum, tungsten, molybdenum, rhenium, and / or cobalt-chromium alloy. In this configuration, the braid 300 can provide increased flexibility at the distal end of the catheter 10 by changing the metal composition of the inner core 312 as the braid 300 extends along the length of the catheter 10.

[0057] 4A-4C show further examples of wire segments 408 of the braid 400. In FIGS. 4A-4C, the outer shell 410 is divided into an upper semi-cylinder 420 and a lower semi-cylinder 422 relative to the longitudinal axis LA. The upper semi-cylinder 420 can include a first metal and / or a combination of first metals, and the lower semi-cylinder 422 can include a second metal and / or a combination of second metals. The second metal and / or a combination of second metals in the lower semi-cylinder 422 can have a higher density than the first metal and / or a combination of first metals. This allows the wire segment 408 to automatically rotate and position itself so that the lower semi-cylinder 422 of the wire segment 408 is oriented toward the inner lumen of the braid 400. This configuration can reduce the likelihood of twisting of the wire segment 408 during braiding. The inner core 412 can be made of a metal having a different density than both the first metal and / or combination of first metals of the upper semi-cylinder 420 and the second metal and / or combination of second metals of the lower semi-cylinder 422. The inner core 412 can be made of a metal having a higher density than the first metal and / or combination of metals and a lower density than the second metal and / or combination of metals.

[0058] By manipulating the density relationship between the first metal of the upper semi-cylinder 420, the second metal of the lower semi-cylinder 422, and the metal composition of the inner core 412, one or more air channels 414 can be formed in the top semi-cylinder 420 to further prevent twisting of the wire segments 408. Any number of air channels 414 can be formed in the top semi-cylinder 420. The air channels 414 can have any shape. As shown in FIG. 4B, the top semi-cylinder 420 can include three air channels 414 having circular cross-sections. The air channel 414 can have a diameter 416 of approximately 0.01 millimeters (0.00045 inches). As shown in FIG. 4C, the top cylinder 420 can include one air channel 414 having a substantially semi-circular cross-sectional shape, such that the air channel 414 can resemble the shape and / or size of the top semi-cylinder 420. The semi-circular air channel 414 may have a diameter 418 of approximately 0.05 millimeters (0.002 inches).

[0059] By incorporating one or more air channels 414 as shown in Figures 4B and 4C, the density difference between the upper and lower semi-cylinders 420 and 422 can be further differentiated, thereby further biasing the wire segments 408 to orient the lower semi-cylinder 422 toward the lumen of the braid 400 and positioning it to prevent twisting during braiding.

[0060] 5A is a diagram of a catheter 10 including a first braid 506 and a second braid 508. In this configuration, the first braid 506 and the second braid 508 can be used as alternative wire braids in place of the braids 100, 200, 300, and 400 shown in FIGS. 1A-4C. The catheter 10 can include a tubular body 120. The tubular body 120 can have a proximal portion 502 and a distal portion 504. The first braid 506 can be disposed over the proximal portion 502 of the tubular body 120, and the second braid 508 can be disposed over the distal portion 504 of the tubular body 120.

[0061] The first braid 506 can be made from a first plurality of wire segments 514, and the second braid 508 can be made from a second plurality of wire segments 516. The first braid 506 can be constructed to have a lower number of picks per inch than the second braid 508. By way of example, the first braid 506 can have between about 20 and about 45 picks per inch, and the second braid 508 can have between about 120 and about 200 picks per inch.

[0062] The first braid 506 and the second braid 508 can be arranged on the tubular body 120 such that gaps between the first braid 506 and the second braid 508 are minimized, as gaps can cause potential kink points. In one example, the first braid 506 and the second braid 508 can abut one another such that the first braid 506 transitions into the second braid 508, and thus the first plurality of wire segments 514 transitions into the second plurality of wire segments 516. Alternatively, the first braid 506 and the second braid 508 can overlap. By way of example, the distal end of the first braid 506 can overlap the proximal end of the second braid 508. Such overlapping of the first braid 506 and the second braid 508 can eliminate gaps between the two braids 506, 508, thereby reducing the possibility of kinking points and failure to deliver the catheter 10 to the proper position.

[0063] FIG. 5B illustrates a cross-sectional view of a wire segment 514 of the first braid 506. As shown in FIGS. 2B-4C, the wire segment 514 can include a first outer shell 510a having a substantially circular cross-sectional shape. The wire segment 514 can have a first inner core 512a that can have a substantially rectangular cross-sectional shape. The first inner core 512a of the wire segment 514 can have a composition that includes a first metal. The first metal can be a relatively rigid metal (e.g., cobalt chromium, martensitic steel, chromium steel).

[0064] FIG. 5C shows a cross-sectional view of a wire segment 516 of the second braid 508. The wire segment 516 can also have a second outer shell 510b having a substantially circular cross-sectional shape. However, unlike the first braid 506, the wire segment 516 can have a second inner core 512b having a substantially circular cross-sectional shape. The second inner core 512b of the wire segment 516 can have a composition including a second metal that is less rigid than the first metal of the inner core 512b of the wire segment 514. As shown in FIG. 5D, in some embodiments, the second inner core 512b of the wire segment 516 can be an air cavity 520 such that the second inner core 512b does not include any metal.

[0065] By varying the cross-sectional shape and metal composition of the inner core 512 with respect to the first braid 506 disposed on the proximal portion 502 of the tubular body 120 and the second braid 508 disposed on the distal portion 504 of the tubular body 120, the catheter 10 can have a relatively flexible distal shaft and a relatively stiff proximal shaft, such that the catheter 10 does not have to sacrifice column strength in order to have the flexibility necessary to navigate tortuous vasculature.

[0066] 6 shows a flowchart outlining an exemplary method 600 of manufacturing the catheter braid 200. In step 602, a catheter 10 is provided having a tubular body 120. The tubular body can have a proximal portion and a distal portion.

[0067] At step 604, a plurality of wire segments 208 may be provided. Each wire segment of the plurality of wire segments 208 may have an outer shell 210 and an inner core 212 extending through the outer shell 210.

[0068] In step 606, the cross-sectional shape of the inner core 212 may be changed such that the cross-sectional shape of the inner core 212 transitions from substantially rectangular to substantially circular.

[0069] In step 608, the multiple wire segments 208 may be braided around the tubular body 120 such that the cross-sectional shape of the inner core 212 is substantially rectangular near the proximal portion of the tubular body 120 and substantially circular near the distal portion of the tubular body 120.

[0070] 7 shows a flowchart outlining an additional and / or alternative exemplary method 700 of manufacturing the catheter braid 200, 300. In step 702, a catheter 10 is provided having a tubular body 120. The tubular body can have a proximal portion and a distal portion.

[0071] At step 704, a plurality of wire segments 208, 308 may be provided. Each wire segment of the plurality of wire segments 208, 308, 408 may have an outer shell 210, 310 and an inner core 212, 312 extending through the outer shell 210, 310.

[0072] In step 706, the material composition of the inner core 212, 312 can be varied so that the material composition of the inner core 212, 312 transitions from relatively stiff to relatively flexible. For example, the material composition of the inner core 212, 312 can include different metals to create wire segments 208, 308 with different stiffnesses.

[0073] In step 708, multiple wire segments 208, 308 may be braided around the tubular body 120 such that the cross-sectional shape of the inner core 212, 312 is relatively rigid near the proximal portion of the tubular body 120 and relatively flexible near the distal portion of the tubular body 120.

[0074] The descriptions contained herein are examples of embodiments of the present invention and are not intended to limit the scope of the present invention in any way. As described herein, the present invention contemplates numerous variations and modifications of the inventive delivery and release system for vaso-occlusive devices, including numerous configurations, numerous stiffness characteristics, and methods of delivery thereof. There are also many possible variations in materials and release mechanism configurations. These modifications will be apparent to those skilled in the art to which the present invention pertains, and are intended to be encompassed within the scope of the following claims.

[0075] [Embodiment] (1) A catheter braid extending a length having a proximal portion having a proximal end and a distal portion having a distal end, the catheter braid including a plurality of wire segments, each wire segment comprising: an outer shell having a first material composition; an inner core extending through the outer shell and having a second material composition different from the first material composition along at least a portion of the length, the inner core having a first cross-sectional shape near the proximal end and a second cross-sectional shape near the distal end, the first cross-sectional shape transitioning to the second cross-sectional shape along the length. (2) A catheter braid as described in embodiment 1, wherein the proximal portion has a first number of picks per inch and the distal portion has a second number of picks per inch, the first number of picks per inch being less than the second number of picks per inch. (3) The catheter braid according to embodiment 2, wherein the first number of picks per inch is about 20 to about 45, and the second number of picks per inch is about 120 to about 200. (4) A catheter braid as described in embodiment 1, wherein the first cross-sectional shape is substantially rectangular and the second cross-sectional shape is substantially circular. (5) The catheter braid of embodiment 1, further comprising a transition portion extending over at least a portion of the proximal portion and over at least a portion of the distal portion, the transition portion having a variable cross-sectional shape that gradually transitions from being substantially rectangular near the proximal portion to being substantially circular near the distal portion.

[0076] (6) The catheter braid of embodiment 5, wherein the second material composition comprises a first metal in the proximal portion, a second metal in the transition portion, and a third metal in the distal portion, the first metal having a higher stiffness than the second metal and the third metal, and the second metal having a higher stiffness than the third metal. (7) A catheter braid as described in embodiment 1, wherein the inner core is hollow at the distal end of the distal section. (8) A catheter braid as described in embodiment 1, wherein the first cross-sectional shape is substantially rectangular and the second cross-sectional shape is substantially rectangular. (9) The catheter braid of embodiment 8, wherein the inner core comprises a first metal in the proximal portion and a second metal in the distal portion, the first metal having a higher stiffness than the second metal. (10) A catheter braid as described in embodiment 8, wherein the outer shell includes an upper semi-cylinder relative to the longitudinal axis and a lower semi-cylinder relative to the longitudinal axis.

[0077] (11) The catheter braid of embodiment 10, wherein the inner core comprises a first metal, the upper semi-cylinder comprises a second metal, and the lower semi-cylinder comprises a third metal, the third metal having a higher density than the first metal and the second metal, and the first metal having a higher density than the second metal. (12) A catheter braid as described in embodiment 10, wherein the upper semi-cylinder includes one or more air channels. (13) A catheter, a tubular body including a proximal portion and a distal portion; a first braid disposed over the proximal portion, the first braid including a first plurality of wire segments, each wire segment having a first outer shell and a first inner core having a substantially rectangular cross-sectional shape; a second braid disposed over the distal portion, the second braid including a second plurality of wire segments, each wire segment having a second outer shell and a second inner core having a substantially circular cross-sectional shape. (14) The catheter of embodiment 13, wherein the first braid has a first number of picks per inch and the second braid has a second number of picks per inch, the second number of picks per inch being greater than the first number of picks per inch. (15) The catheter of embodiment 13, wherein the second inner core of each wire segment of the second plurality of wire segments is hollow near the distal end of the distal portion.

[0078] (16) A catheter braid disposed along the length of the catheter, a proximal portion including a wire segment having a first cross-sectional shape, the first cross-sectional shape being substantially rectangular; a distal portion including wire segments having a second cross-sectional shape, the second cross-sectional shape being substantially circular. (17) The catheter braid of embodiment 16, wherein the proximal portion has a lower number of picks per inch than the distal portion. (18) The catheter braid of claim 16, further comprising a transition section disposed between the proximal section and the distal section, the transition section having a higher number of picks per inch than the proximal section and a lower number of picks per inch than the distal section. (19) The catheter braid of embodiment 18, wherein the transition section extends over a length of about 5 to about 15 centimeters and has a variable cross-sectional shape, the variable cross-sectional shape being substantially rectangular near the proximal section and substantially circular near the distal section. (20) The catheter braid of embodiment 18, wherein the proximal section has about 20 to about 50 picks per inch, the transition section has about 50 to about 90 picks per inch, and the distal section has about 110 to about 200 picks per inch.

Claims

1. A catheter braid extending a length having a proximal portion having a proximal end and a distal portion having a distal end, the catheter braid including a plurality of wire segments, each wire segment comprising: an outer shell having a first material composition; an inner core extending through the outer shell and having a second material composition different from the first material composition along a portion of the length, the inner core having a first cross-sectional shape near the proximal end and a second cross-sectional shape near the distal end, the first cross-sectional shape transitioning to the second cross-sectional shape along the length; The catheter braid, wherein the inner core defines a cavity near the distal end of the distal section.

2. 10. The catheter braid of claim 1, wherein the proximal portion has a first number of picks per inch and the distal portion has a second number of picks per inch, the first number of picks per inch being less than the second number of picks per inch.

3. 3. The catheter braid of claim 2, wherein the first number of picks per inch is about 20 to about 45 and the second number of picks per inch is about 120 to about 200.

4. The catheter braid of claim 1 , wherein the first cross-sectional shape is substantially rectangular and the second cross-sectional shape is substantially circular.

5. 10. The catheter braid of claim 1, further comprising a transition portion extending across at least a portion of the proximal portion and across at least a portion of the distal portion, the transition portion having a variable cross-sectional shape that gradually transitions from being substantially rectangular near the proximal portion to being substantially circular near the distal portion.

6. 6. The catheter braid of claim 5, wherein the second material composition comprises a first metal in the proximal portion, a second metal in the transition portion, and a third metal in the distal portion, the first metal having a higher stiffness than the second metal and the third metal, and the second metal having a higher stiffness than the third metal.

7. The catheter braid of claim 1 , wherein the first cross-sectional shape is substantially rectangular and the second cross-sectional shape is substantially rectangular.

8. 8. The catheter braid of claim 7, wherein the inner core comprises a first metal in the proximal portion and a second metal in the distal portion, the first metal having a higher stiffness than the second metal.

9. The catheter braid of claim 7 , wherein the outer shell comprises an upper semi-cylinder relative to the longitudinal axis and a lower semi-cylinder relative to the longitudinal axis.

10. 10. The catheter braid of claim 9, wherein the inner core comprises a first metal, the upper semi-cylinder comprises a second metal, and the lower semi-cylinder comprises a third metal, the third metal having a higher density than the first metal and the second metal, and the first metal having a higher density than the second metal.

11. The catheter braid of claim 9 , wherein the upper half-cylinder includes one or more air channels.

12. A catheter braid as described in claim 1, wherein the outer shell has a substantially circular cross-sectional shape from near the proximal end to near the distal end.

13. A catheter braid as described in claim 12, wherein the outer shell has substantially the same diameter from near the proximal end to near the distal end.

14. A catheter comprising: a tubular body including a proximal portion and a distal portion; a first braid disposed over the proximal portion, the first braid including a first plurality of wire segments, each wire segment of the first plurality of wire segments having a first outer shell and a first inner core having a substantially rectangular cross-sectional shape; a second braid disposed over the distal portion, the second braid including a second plurality of wire segments, each wire segment of the second plurality of wire segments having a second outer shell and a second inner core having a substantially circular cross-sectional shape; A catheter, wherein the second inner core of each wire segment of the second plurality of wire segments defines a cavity near the distal end of the distal portion.

15. 15. The catheter of claim 14, wherein the first braid has a first number of picks per inch and the second braid has a second number of picks per inch, the second number of picks per inch being greater than the first number of picks per inch.

16. A catheter as described in claim 14, wherein the first outer shell and the second outer shell have a substantially circular cross-sectional shape.

17. The catheter of claim 16, wherein the first outer shell and the second outer shell have substantially the same diameter.

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