Conduit braid wire having variable cross-sectional shape

Abstract

The invention is entitled "Catheter Braided Wire with Variable Cross-Section Shape." The disclosed technology can include a catheter braid that includes wire segments with varying cross-sectional shapes. The wire segments at a proximal portion of the braid can have a substantially rectangular cross-sectional shape, while the wire segments at a distal portion of the braid can have a substantially circular cross-sectional shape. The cross-sectional shape can gradually transition from rectangular to circular along the length of the braid. The catheter braid can include wire segments that have an outer core and an inner core. The inner core at the proximal section of the braid can have a substantially rectangular cross-sectional shape, while 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 to provide a smooth transition. The composition of the inner core can vary along the length of the braid.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims the benefit of U.S. Patent Application 63 / 110,613, filed November 6, 2020, the entire contents and substance of which are hereby incorporated by reference as if fully set forth below. TECHNICAL FIELD

[0003] The present invention relates generally to devices and methods for accessing blood vessels during intravascular medical treatment. More particularly, the present disclosure relates to catheters having improved flexibility while maintaining axial stiffness. BACKGROUND

[0004] Catheters provide a wide range of functions in intravascular medical treatment. Catheters are typically small 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 various other purposes. By varying the materials or adjusting the way the catheter is manufactured, different sections of the catheter can be tailored for specific applications.

[0005] Several designs and methods have been proposed to navigate a catheter to a target site. In one method, a catheter is assembled over a guidewire and slides along the guidewire, which is used to access the target site. However, a small guidewire almost always has greater reach and distal flexibility than a catheter tube. Newer designs have been proposed that utilize various methods to vary the stiffness between the proximal and distal portions of the catheter, such as braids or wound sets of polymer tubes that typically have wires or bands involving other materials for reinforcement. Current designs can include a more flexible, more pliable distal portion of the catheter while increasing stiffness toward the proximal portion of the catheter. In such designs, a smooth transition from the more flexible, more pliable distal portion to the more rigid proximal portion can facilitate successful use of the catheter for vascular applications. However, some existing designs lack the strength that can be used for some medical procedures or contain abrupt stiffness or geometric changes that can impede trackability, introduce significant stress concentrations, and potentially increase the likelihood of device kinking or buckling. As a result, some designs typically have pushability, trackability, or kink levels that are not acceptable for widespread adoption by physicians.

[0006] Accordingly, there is a need for systems, devices, and methods that can provide a smooth transition from a relatively rigid proximal portion to a relatively pliable distal portion of a catheter while maintaining axial stiffness. SUMMARY

[0007] Generally, it is an object of the present disclosure to provide a catheter braid that includes wire segments having varying cross-sectional shapes to provide a relatively soft, pliable catheter shaft at a distal portion of the braid and a relatively rigid catheter shaft at a proximal portion of the braid. In one embodiment, the wire segments at the proximal portion can have a substantially rectangular cross-sectional shape, while the wire segments at the distal portion can have a substantially circular cross-sectional shape. The cross-sectional shape of the wire segments can gradually transition from a rectangular cross-sectional shape to a circular cross-sectional shape to provide a smooth transition that minimizes the potential for kinking. In further embodiments, 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, while 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 to provide a smooth transition. The composition of the outer core can be different than the composition of the inner core, and the composition of the inner core can vary as the wire segments extend 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 stiff and rigid shaft at the proximal portion to a soft pliable shaft at the distal portion.

[0008] 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 end and the distal end. The catheter braid can include a plurality of wire segments, each wire segment including an outer core and an inner core. The outer core can have a first material composition. The inner core can extend through the outer core and can have a second material composition different than 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 proximate the proximal end and a second cross-sectional shape proximate the distal end. The first cross-sectional shape can transition to the second cross-sectional shape along the length of the catheter braid.

[0009] The proximal portion of the catheter braid can have a first number of wefts per inch, and the distal portion of the catheter braid can have a second number of wefts per inch. The first number of wefts per inch can be less than the second number of wefts per inch.

[0010] The first number of wefts per inch can be between about 20 and about 45. The second number of wefts per inch can be between about 120 and about 200.

[0011] The first cross-sectional shape can be substantially rectangular, and the second cross-sectional shape can be substantially circular.

[0012] 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 be substantially rectangular proximate the proximal portion and gradually transition to substantially circular proximate the distal portion.

[0013] The second material composition can include a first metal at the proximal portion, a second metal at the transition portion, and a third metal at the distal portion. The first metal can have a greater stiffness than the second metal and the third metal. The second metal can have a greater stiffness than the third metal.

[0014] The inner core can be a hollow cavity at a distal end of the distal portion.

[0015] The first cross-sectional shape can be substantially rectangular, and the second cross-sectional shape can be substantially circular.

[0016] The inner core can include a first metal at the proximal portion and a second metal at the distal portion. The first metal can have a greater stiffness than the second metal.

[0017] The outer shell can include an upper half-cylinder relative to the longitudinal axis and a lower half-cylinder relative to the longitudinal axis.

[0018] The inner core can include a first metal, the upper half-cylinder can include a second metal, and the lower half-cylinder can include a third metal. The third metal can have a greater density than the first metal and the second metal, and the first metal can have a greater density than the second metal.

[0019] The upper half-cylinder can include one or more air channels.

[0020] Another example catheter can include a tubular body, a first braid, and a second braid. The tubular body can include a proximal portion and a distal portion. The first braid can be disposed over the proximal portion. The first braid can include a first plurality of segments. Each segment can include a first outer shell and a first inner core having a substantially rectangular cross-sectional shape. The second braid can be disposed over the distal portion. The second braid can include a second plurality of segments. Each segment can have a second outer shell and a second inner core having a substantially circular cross-sectional shape.

[0021] The first braid can have a first number of wefts per inch, and the second braid can have a second number of wefts per inch. The second number of wefts per inch can be greater than the first number of wefts per inch.

[0022] The inner core of each segment of the second plurality of segments can be a hollow cavity proximate a distal end of the distal portion.

[0023] Another example catheter braid disposed along a length of a catheter can include a proximal portion and a distal portion. The proximal portion can include a segment having a first cross-sectional shape that is substantially rectangular. The distal portion can include a segment having a second cross-sectional shape that is substantially circular.

[0024] The proximal portion can have a smaller number of wefts per inch than the distal portion.

[0025] The catheter braid can further include a transition portion disposed between the proximal portion and the distal portion. The transition portion can have a greater number of wefts per inch than the proximal portion and a smaller number of wefts per inch than the distal portion.

[0026] The transition portion can extend a length between about 5 centimeters and about 15 centimeters and can have a variable cross-section. The variable cross-section can be substantially rectangular proximate the proximal portion and substantially circular proximate the distal portion.

[0027] The proximal portion can have a number of wefts per inch between about 20 and about 50, the transition portion can have a number of wefts per inch between about 50 and about 90, and the distal portion can have a number of wefts per inch between about 110 and about 200.

[0028] The features of the above-described example catheter can be combined in accordance with the teachings herein and / or in ways that would be apparent to those of ordinary skill in the art. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above aspects and further aspects of the present application will be further discussed with reference to the following description and drawings, wherein like numbers indicate similar structural elements and features in the various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the application. The drawings depict one or more specific embodiments in accordance with the present application in which:

[0030] Figure 1A Illustrations of a catheter including an example braid in accordance with aspects of the present application;

[0031] Figure 1B Illustrations of a braid in accordance with aspects of the present application Figure 1A Illustrations of an example strand of a braid in accordance with aspects of the present application;

[0032] Figure 1C Cross-sectional view of a strand at a proximal portion of an example braid in accordance with aspects of the present application Figure 1B

[0033] Figure 1D Cross-sectional view of a strand at a distal portion of an example braid in accordance with aspects of the present application Figure 1B

[0034] Figure 2A Illustrations of a catheter including an example braid in accordance with aspects of the present application;

[0035] Figure 2B Cross-sectional view of a strand at a proximal portion of an example braid in accordance with aspects of the present application Figure 2A ​​​

[0036] Figure 2C Cross-sectional view of a strand at a transition portion of an exemplary braid in accordance with aspects of the present application; Figure 2A

[0037] Cross-sectional view of a strand at a distal portion of an exemplary braid in accordance with aspects of the present application; Figure 2D Figure 2A Cross-sectional view of an alternative exemplary strand of a braid in accordance with aspects of the present application;

[0038] Figures 3A-3B Figure 2A Cross-sectional view of an alternative exemplary strand of a braid in accordance with aspects of the present application;

[0039] Figures 4A-4C Cross-sectional view of an alternative exemplary strand of a braid in accordance with aspects of the present application; Figure 2A

[0040] Figure 5A Diagram of a catheter including a first braid and a second braid in accordance with aspects of the present application;

[0041] Figure 5B Cross-sectional view of a strand of a first braid in accordance with aspects of the present application; Figure 5A

[0042] Cross-sectional view of a strand of a second braid in accordance with aspects of the present application; Figures 5C-5D Figure 5A

[0043] Figure 6 Flowchart outlining an exemplary method of manufacturing an exemplary braid; and

[0044] Figure 7 Flowchart outlining an additional or alternative method of manufacturing an exemplary braid. DETAILED DESCRIPTION

[0045] ​​​​​The disclosed technology can include a catheter braid that includes wire segments having varying cross-sectional shapes along the length of the braid to provide a relatively soft flexible shaft at a distal portion, a relatively rigid shaft at a proximal portion, and a gradual transition between the flexible shaft and the rigid shaft. In one embodiment, the wire segments at the proximal portion of the braid can have a substantially rectangular cross-sectional shape, thereby providing a stiff proximal shaft and maximizing column strength. The cross-sectional shape of the wire segments can gradually transition from rectangular to circular to provide increased radial flexibility at the distal portion. By gradually transitioning from one cross-sectional shape to a different cross-sectional shape, the likelihood of kinking can be reduced. In further embodiments, the wire segments can have an outer core and an inner core. The inner core at the proximal section of the braid can have a substantially rectangular cross-sectional shape, while 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 to provide a smooth transition. The composition of the outer shell can be different than the composition of the inner core, and the composition of the inner core can vary as the wire segments extend 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 stiff and rigid shaft at the proximal portion to a soft flexible shaft at the distal portion without sacrificing proximal shaft push efficiency.

[0046] While example embodiments of the disclosed technology are explained in detail herein, it should be understood that other embodiments can be contemplated. Thus, it is not intended that the scope of the disclosed technology be limited to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The disclosed technology is capable of other embodiments and of being practiced or carried out in various ways.

[0047] It should also be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. By "comprising" or "containing" or "including" it is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but not excluding the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.

[0048] In describing example embodiments, terminology will be employed for the sake of clarity. Each term is intended to encompass its broadest meaning as understood by those skilled in the art and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. It is also to be understood that a recitation of one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those explicitly identified. Steps of a method can be performed in an order different than that described herein without departing from the scope of the disclosed technology. Similarly, it is also to be understood that a recitation of one or more components in an apparatus or system does not preclude the presence of additional components or intervening components between those explicitly identified.

[0049] As discussed herein, vasculature can be vasculature of any "subject" or "patient," including any human or animal. It is to be understood that an animal can be of any applicable type, including but not limited to a mammal, a veterinary animal, a farm animal, or a pet class animal, etc. For example, an animal can be an experimental animal specifically selected to have certain characteristics similar to humans (e.g., a rat, a dog, a pig, a monkey, etc.). It is to be understood that a subject can be, for example, any applicable human patient.

[0050] As discussed herein, the term "about" or "approximately" with respect to any numerical or range of values indicates suitable dimensional tolerances that allow the parts or components to function for their intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of values ±20% of the recited value, e.g., "about 90%" can refer to a range of values from 71% to 99%.

[0051] As used herein, in describing geometric characteristics, the term "substantially" indicates suitable dimensional tolerances that allow portions of components to function for their intended purpose, and the geometric characteristic is still properly described as approximating the described strict shape despite deviations from the strict shape. For example, a "substantially" rectangular shape can deviate from a strict rectangular shape, e.g., rounded corners, imprecisely parallel sides, and / or imprecisely 90° angles, where the "substantially" rectangular shape achieves similar functionality to a strict rectangular shape. The "substantially" rectangular shape can be close enough to a strict rectangular shape that "rectangular" is a reasonably appropriate descriptor of the plain and ordinary meaning of the word "rectangular." A rectangle with a semicircle at each short side, sometimes referred to as a "stadium" shape, can be considered "substantially" rectangular because "stadium" is a less common shape descriptor than "rectangular," and the feature with the "stadium" shape retains its functionality when the "stadium" shape is replaced with a "rectangular" shape.

[0052] The drawings illustrate generally hollow or tubular structures in accordance with the present application. As used herein, the terms "tubular" and "tube" are to be interpreted broadly and are not limited to structures that are right cylinders or have a complete circular cross-section or have a uniform cross-section along their entire length. For example, tubular structures or systems are generally illustrated as structures that are substantially right cylinders. However, the tubular systems can have tapered or curved outer surfaces without departing from the scope of the present application.

[0053] Referring now to the drawings, Figure 1A A catheter 10 is shown having a braid 100. The catheter 10 can include an elongate tubular body 120. The tubular body 120 can be made from various medical grade polymers such as PTFE, polyether block amide or nylon. The catheter 10 can include a braid 100 disposed over the tubular body 120. The braid 100 can extend a length L. The braid 100 can extend substantially the same length L 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 between about 45 centimeters to about 55 centimeters, the transition portion 104 can extend between about 5 centimeters and about 15 centimeters, and the distal portion 106 can extend between about 25 centimeters and about 35 centimeters.

[0054] The braid 100 can be made from a plurality of 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-chrome, molybdenum and niobium alloys, or any other hard metallic alloy. The braid 100 can have a varying number of wefts per inch along its length L. The proximal portion 102 of the braid 100 can have a lower number of wefts per inch compared to the transition portion 104 and the distal portion 106, thereby facilitating axial stiffness. By way of example, the proximal portion 102 can have between about 20 and about 50 wefts per inch. To provide increased radial flexibility near the distal end of the catheter 10, the number of wefts per inch of the braid 100 can increase within the transition portion 104 and the distal portion 106. The transition portion 104 can have between about 50 and about 90 wefts per inch. The distal portion 106 can have between about 110 and about 200 wefts per inch, thereby providing a flexible catheter shaft capable of effectively navigating through tortuous vasculature.

[0055] As further discussed herein, each of the plurality of line segments 108 may 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 may facilitate a gradual transition of the line segment 108 from the first cross-sectional shape to the second cross-sectional shape.

[0056] The catheter 10 may also include a marking strip 110 disposed near the distal end 122 of the tubular body 120. The marking strip 110 may be attached to the tubular body 120 to provide radiation impermeability, thereby allowing the user to precisely position the catheter 10 within the patient's vascular system. By way of example, the marking strip 110 may be a platinum marking strip.

[0057] A polymer sheath 124a may be disposed around the braid 100. A first polymer sheath 124a may be disposed around the proximal portion 102 of the braid 100. In some cases, the first polymer sheath 124a may be disposed around at least a portion of the proximal portion 102 and the transition portion 104. The first polymer sheath 124a may have a stiffness between approximately 60 and approximately 80. A second polymer sheath 124b may 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 sheath 124b may extend to the end 122 of the tubular body and thus cover the marking tape 110. The second polymer sheath 124b may have a stiffness between approximately 40 and approximately 80.

[0058] Figure 1B It shows Figure 1A The line segment 108 of the woven fabric 100 shown. Figure 1C and Figure 1D As shown Figure 1B The cross-sections of the corresponding segment portions 108a and 108c of line segment 108 shown. See also Figures 1A-1D As the woven fabric 100 extends from its proximal portion 102 to its distal portion 106, the line segments 108 of the woven fabric 100 may have varying cross-sections. For example... Figure 1B and Figure 1C As shown, the proximal portion 102 may include a line segment portion 108a having a substantially rectangular cross-section. The line segment portion 108a within the proximal portion 102 of the braid 100 may be designed to maximize the width 112. By way of example, the width 112 of the line segment portion 108a at the proximal portion 102 may be approximately 0.25 mm (0.01 inch). By maximizing the width 112 of the line segment portion 108a, the resulting braid 100 may substantially resemble a metal slub tube. The line segment portion 108a may also be designed to have a height 110 of approximately 0.01 mm (0.0004 inch). Therefore, the proximal portion 102 of the braid 100 can provide sufficient column strength and axial stiffness.

[0059] like Figure 1B and Figure 1D As shown, the distal portion 106 may include a segment portion 108c having a substantially circular cross-section. By way of example, the segment portion 108c may have a diameter 114 of approximately 0.06 mm (0.0025 inches). Additionally, when the segment portion 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 remain relatively small, allowing the overall inner diameter of the catheter 10 to be larger than that of several commercially available catheters. This allows for an increase in the lumen used to assist in the translation of the catheter through the catheter 10 as needed, or it may allow for an increase in the lumen used for aspiration. The circular cross-section of the segment portion 108c provides increased flexibility compared to the segment portion 108a within the proximal portion 102. Having a flexible catheter tip can facilitate navigation of the distal end of the catheter 10 through tortuous vascular systems.

[0060] like Figure 1B As shown, the transition portion 104 of the braid 100 may include a segment portion 108b with a varying cross-sectional shape. The segment portion 108b may have a substantially rectangular cross-sectional shape approaching the proximal portion 102 and gradually transition to a substantially circular cross-sectional shape approaching the distal portion 106. By gradually transitioning from the rectangular cross-sectional shape of the segment portion 108a within the proximal portion 102 to the circular cross-sectional shape of the segment portion 108c within the distal portion 106, the likelihood of one or more kinks can be reduced. This smooth transition facilitates force transmission when the catheter 10 is pushed distally through the vascular system.

[0061] By altering the cross-sectional shape of the braid 100 as it extends along the tubular body 120 of the conduit 10 (by altering the cross-sectional shape of the lines 108 of the braid 100), the proximal axis of the conduit 10 can have the desired stiffness and column strength for adequate navigation, thereby reducing the likelihood of damage during navigation, while the distal axis of the conduit 10 can have the desired flexibility and trackability.

[0062] Figure 2A The catheter 10 is shown, including alternative exemplary braids 200, 300, and 400. Figures 2A to 29A show catheters 10 including alternative exemplary braids 200, 300, and 400. Figure 2D An exemplary braided fabric 200 comprising multiple line segments 208 is shown. Figure 2A and Figure 3A to Figure 3B An exemplary braided fabric 300 comprising multiple line segments 308 is shown. Figure 2A as well as Figure 4A and Figure 4BAn exemplary braid 400 including a plurality of wire segments 408 is shown. Thus, exemplary braids 200, 300, 400 can be similarly disposed over the tubular body 120 of the catheter 10, however, some characteristics of the plurality of wire segments 208, 308, 408 can vary according to the exemplary braid 200, 300, 400.

[0063] The catheter 10 can include a tubular body 120. The braid 200, 300, 400 can extend a length L over the catheter 10. In some cases, the braid 200, 300, 400 can extend over a portion of the catheter 10. Alternatively, the braid 200, 300, 400 can extend over an entire length of the catheter 10. The braid 200, 300, 400 can have a proximal portion 202, 302, 402 having a proximal end 202A, 302A, 402A and a distal portion 206, 306, 406 having a distal end 206A, 306A, 406A. In particular, the braid 200 can further include a transition portion 204 that can extend over at least a portion of the proximal portion 202 and at least a portion of the distal portion 206.

[0064] The braid 200, 300, 400 can be made of a plurality of wire segments 208, 308, 408 and can have a varying number of wefts per inch as the braid 200, 300, 400 extends the length L along the catheter 10. The proximal portion 202, 302, 402 of the braid 200, 300, 400 can have a number of wefts per inch between about 20 and about 45. The distal portion 206, 306, 406 of the braid 200, 300, 400 can have a number of wefts per inch between about 120 and about 200.

[0065] Figures 2B-2D A cross-sectional view of the respective wire segment portions 208a, 208b, 208c of each wire segment 208 of the braid 100b is shown. The wire segment 208 can be a drawn filled tube (“DFT”) in which each wire segment 208 has an outer shell 210 and an inner core 212. The outer shell 210 can have a material composition and the inner core 212 can have a material composition that is different than the material composition of the outer core 212 over at least a portion of the wire segment 208. For wire segments 208 having an inner core 212 with a circular cross-section as shown in Figure 2D For the portion 208c of the wire segment 208 having an inner core 212 with a circular cross-section as shown in Figure 2B and Figure 2CThe portions 208a, 208b of the wire segment 208 shown with the non-circular inner core 212 can bend or flex in a preferred direction dictated by the non-circular shape of the inner core 212 while maintaining a circular outer profile. The first metal composition of the outer shell 210 can remain the same as the braid 100b and extend along the length L of the braid 200. The second composition of the inner core 212 can vary as the braid 200 extends from the proximal portion 202 to the distal portion 206 such that the second composition can differ from the first composition along at least a portion of the length L of the braid 200. The inner core 212 can have a varying cross-sectional shape as the braid 100b extends over the tubular body 120. By gradually changing the cross-sectional shape of the inner core 212 and / or changing the material composition of the inner core 212, the catheter 10 can have a relatively rigid proximal shaft and a relatively flexible distal shaft, thereby providing effective navigation through the vasculature.

[0066] Figure 2B A cross-sectional view of a first wire segment portion 208a of the wire segment 208 is shown. 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 the outer shell 210 and the 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 includes stainless steel and the composition of the inner core 212 includes a metal and / or metal combination that is relatively rigid compared to the outer shell 210 over the proximal portion 202 of the wire segment 208. By way of example, the inner core 212 of the first wire segment portion 208a can be made of cobalt-chromium, 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, where the material encompassing the largest cross-sectional area has the greatest impact on the overall stiffness of the wire segment. Thus, in examples where the inner core 212 has a larger cross-sectional area than 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 the inner core 212 can be based on the Young's modulus and / or ultimate tensile strength ("UTS") values of the metal composition of the outer shell 210 and the inner core 212.

[0067] The inner core 212 can have a substantially rectangular cross-sectional shape. The inner core 212 has a length 218 that is similar to the diameter 214 of the outer shell 210 and a width 216. 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 between the length 218 of the inner core and the width 216 of the inner core can be approximately 6 to 1. By having a circular outer shell 210 with an inner core 212 that has a substantially rectangular cross-sectional shape and a relatively rigid metal composition (e.g., having a Young's modulus and / or UTS that is substantially similar to or greater than the outer shell 210), the wire segment portion 208a can allow for a circular wire, but with similar properties and functionality as a flat wire. Thus, the first wire segment portion 208a can provide increased axial stiffness and rigidity at the proximal end of the catheter 10 compared to a catheter having a completely circular wire without the inner core 212.

[0068] Figure 2C A cross-sectional view of a second wire segment portion 208b of the wire segment 208 is shown. The second wire segment portion 208b can be disposed over 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 metal combination that is less rigid (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 a diameter 214 that is the same as the second wire segment portion 208a. The inner core 212 can have a varying cross-sectional shape. The inner core 212 can have a substantially rectangular cross-sectional shape proximate to the proximal portion 202 and a substantially circular cross-sectional shape proximate to the distal portion 206. As shown, the inner core 212 can have a substantially elongated oval or stadium shape at approximately the middle of the transition portion 204. The length 222 of the edge 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). By gradually transitioning from the rectangular cross-sectional shape of the wire segment portion 208a in the proximal portion 202 to the circular cross-sectional shape of the wire segment portion 208c in the distal portion 206, the likelihood of kinking can be reduced. Figure 2C As shown, the inner core 212 can have a substantially elongated oval or stadium shape at approximately the middle of the transition portion 204. The length 222 of the edge 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). By gradually transitioning from the rectangular cross-sectional shape of the wire segment portion 208a in the proximal portion 202 to the circular cross-sectional shape of the wire segment portion 208c in the distal portion 206, the likelihood of kinking can be reduced.

[0069] Figure 2DA cross-sectional view of a third line segment portion 208c of the line segment 208 is shown. The third line segment portion 208c can be disposed over the distal portion 206 of the braid 100b. The outer shell 210 can maintain its substantially circular cross-section of the same diameter 214 as the first line segment portion 208a and the second line segment portion 208b. The composition of the inner core 212 can be a third metal and / or metal combination that is less stiff (e.g., has a lower Young's modulus and / or UTS value) than the second metal and the first metal of the inner core 212 at the transition portion 204 and the proximal portion 202, respectively. In some cases, the inner core 212 can be a cavity or void, thereby providing enhanced flexibility of the catheter shaft at 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). Gradual transition from the relatively stiff first metal at the proximal portion 202 to the relatively flexible third metal or even a cavity or void can provide a catheter 10 that can have a proximal shaft that is relatively stiff that can gradually become more flexible distally.

[0070] Varying the cross-sectional shape of the inner core 212 along the proximal portion 202, the transition portion 204, and the distal portion 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, thereby not sacrificing column strength and axial stiffness in order to provide a flexible catheter tip that is capable of navigating tortuous vasculature. The gradual transition of the inner core 212 from a rectangular cross-sectional shape to a circular cross-sectional shape can further reduce the likelihood of kinking during navigation.

[0071] Figure 3A and Figure 3B An alternative exemplary line segment 308 of a braid 300 is shown. Figure 3A A first line segment portion 308a of the line segment 308 is shown. The first line segment portion 308a can be disposed over the proximal portion 302 of the braid 300. Figure 3B A second line segment portion 308b of the line segment 308 is shown. The second line segment portion 308b can be disposed over the distal portion 206 of the braid 300. The line segment 308 can have an outer shell 310 and an inner core 312. As Figures 2B-2DAs shown, 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 can 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 can be approximately 0.04 millimeters (0.0018 inches). Similarly, the width 316a of the inner core 312 at the proximal portion 202 can be substantially equal to the width 316b of the inner core 312 at the distal portion 206. By way of example, the widths 316a, 316b can be approximately 0.01 millimeters (0.0003 inches). In this configuration, the ratio between the length 318 of the inner core and the width 316 of the inner core 312 can be approximately 6 to 1.

[0072] Although Figure 3A and Figure 3B the inner core 312 of the braid 300 has a constant rectangular cross-sectional shape, the inner core 312 of the first wire segment portion 308a at 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 at the distal portion 306 of the braid 300 can include a different one or more metals. The inner core 312 of the first wire segment portion 308a can include a metal or combination of metals that is stiffer than the inner core 312 of the second wire segment portion 308b, and can provide increased column strength to the catheter 10. The second wire segment portion 308b can include a metal or combination of metals that has 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 include nitinol, titanium, austenitic steel, and / or stainless steel, while the first wire segment portion 308a can include martensitic steel, stainless steel, tantalum, tungsten, molybdenum, rhenium, and / or cobalt-chromium alloy. In this configuration, the braid 300 can provide increased flexibility to the distal end of the catheter 10 by varying the metal composition of the inner core 312 as the braid 300 extends along the length of the catheter 10.

[0073] Figures 4A-4C Additional examples of wire segments 408 of a braid 400 are shown. In Figures 4A-4CIn this configuration, the outer shell 410 is divided into an upper half-cylinder 420 and a lower half-cylinder 422 with respect to the longitudinal axis LA. The upper half-cylinder 420 can comprise the first metal and / or first metal combination, and the lower half-cylinder 422 can comprise the second metal and / or second metal combination. The second metal and / or second metal combination in the lower half-cylinder 422 can have a greater density than the first metal and / or first metal combination. As such, the wire segment 408 can automatically rotate and position itself such that the lower half-cylinder 422 of the wire segment 408 is directed toward the interior lumen of the braid 400. In this configuration, the likelihood of the wire segment 408 twisting during braiding can be reduced. The inner core 412 can be made of a metal having a density different from both the first metal and / or first metal combination of the upper half-cylinder 420 and the second metal and / or second metal combination of the lower half-cylinder 422. The inner core 412 can be made of a metal having a greater density than the first metal and / or metal combination and a lesser density than the second metal and / or metal combination.

[0074] To further prevent twisting of the wire segment 408 by manipulating the density relationship of the first metal of the upper half-cylinder 420, the second metal of the lower half-cylinder 422, and the metal composition of the inner core 412, one or more air channels 414 can be formed within the upper half-cylinder 420. Any number of air channels 414 can be created within the upper half-cylinder 420. The air channels 414 can have any shape. As shown in FIG. 4A, the upper half-cylinder 420 can include three air channels 414 having a circular cross-section. Figure 4B Figure 4C As shown in FIG. 4B, the upper half-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 upper half-cylinder 420. The semi-circular air channel 414 can have a diameter 418 of approximately 0.05 millimeters (0.002 inches).

[0075] By incorporating one or more air channels 414 as shown in FIGS. 4A and 4B, the density differential between the upper half-cylinder 420 and the lower half-cylinder 422 can be further distinguished, thereby additionally biasing the wire segment 408 to be positioned such that the lower half-cylinder 422 is directed toward the interior lumen of the braid 400 to prevent twisting during braiding. Figure 4B Figure 4C

[0076] Figure 5A For illustration, a catheter 10 including a first braid 506 and a second braid 508 is shown. In this configuration, the first braid 506 and the second braid 508 can be used as a replacement for the braid 400 as shown in FIGS. 1-4B. Figure 1A ​​​An alternative braid of braids 100, 200, 300, 400 is shown in FIG. 4C. Catheter 10 can include a tubular body 120. Tubular body 120 can have a proximal portion 502 and a distal portion 504. A first braid 506 can be disposed over the proximal portion 502 of the tubular body 120, and a second braid 508 can be disposed over the distal portion 504 of the tubular body 120.

[0077] 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 configured to have a smaller 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.

[0078] The first braid 506 and the second braid 508 can be disposed over the tubular body 120 such that any gap between the first braid 506 and the second braid 508 is 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, a distal end of the first braid 506 can overlap with a proximal end of the second braid 508. Such overlap of the first braid 506 and the second braid 508 can eliminate a gap between the two braids 506, 508, and thus reduce the chance of kink points and unsuccessful delivery of the catheter 10 to the proper location.

[0079] Figure 5B A cross-sectional view of a wire segment 514 of the first braid 506 is shown. As Figure 2B As shown in FIG. 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, which 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-chrome, martensitic steel, chrome steel).

[0080] Figure 5CA cross-sectional view of the wire segment 516 of the second braid 508 is shown. The wire segment 516 can also have a second outer shell 510b that is substantially circular in cross-sectional shape. However, unlike the first braid 506, the wire segment 516 can have a second inner core 512b that is substantially circular in cross-sectional shape. The second inner core 512b of the wire segment 516 can have a composition that includes a second metal that is less rigid than the first metal of the inner core 512b of the wire segment 514. As shown in some examples, 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 contain any metal. Figure 5D

[0081] By varying the cross-sectional shape and metal composition of the inner core 512 relative to the first braid 506 disposed over the proximal portion 502 of the tubular body 120 and the second braid 508 disposed over the distal portion 504 of the tubular body 120, the catheter 10 can have a relatively flexible distal shaft and a relatively rigid proximal shaft such that the catheter 10 does not have to sacrifice column strength to have the necessary flexibility to navigate tortuous vasculature.

[0082] Figure 6 A flowchart outlining an example method 600 of manufacturing a catheter braid 200 is shown. In step 602, a catheter 10 having a tubular body 120 is provided. The tubular body can have a proximal portion and a distal portion.

[0083] In step 604, a plurality of wire segments 208 can be provided. Each wire segment of the plurality of wire segments 208 can have an outer shell 210 and an inner core 212 extending through the outer shell 210.

[0084] In step 606, the cross-sectional shape of the inner core 212 can be varied such that the cross-sectional shape of the inner core 212 transitions from substantially rectangular to substantially circular.

[0085] In step 608, the plurality of wire segments 208 can be braided around the tubular body 120 such that the cross-sectional shape of the inner core 212 is substantially rectangular proximate the proximal portion of the tubular body 120 and substantially circular proximate the distal portion of the tubular body 120.

[0086] Figure 7 A flowchart outlining an additional and / or alternative example method 700 of manufacturing a catheter braid 200, 300 is shown. In step 702, a catheter 10 having a tubular body 120 is provided. The tubular body can have a proximal portion and a distal portion.

[0087] ​In step 704, a plurality of wire segments 208, 308 can be provided. Each wire segment of the plurality of wire segments 208, 308, 408 can have a shell 210, 310 and an inner core 212, 312 extending through the shell 210, 310.

[0088] In step 706, the material composition of the inner core 212, 312 can vary such that the material composition of the inner core 212, 312 transitions from relatively rigid to relatively flexible. For example, the material composition of the inner core 212, 312 can include different metals that form wire segments 208, 308 having different stiffnesses.

[0089] In step 708, the plurality of wire segments 208, 308 can be woven around the tubular body 120 such that the cross-sectional shape of the inner core 212, 312 is relatively rigid proximate the proximal portion of the tubular body 120 and relatively flexible proximate the distal portion of the tubular body 120.

[0090] The description contained herein is an example of embodiments of the present application and is not intended to limit the scope of the present application in any way. As described herein, the present application contemplates many variations and modifications of the delivery and release system of the present application for vascular occlusion devices, including various configurations, various stiffness properties, and methods of delivery thereof. Further, there are many possible variations of configurations of materials and release mechanisms. These modifications will be apparent to one of ordinary skill in the art and are intended to be within the scope of the following claims.

Claims

1. A catheter braid having a proximal portion and a distal portion and extending a length, the proximal portion having a proximal end, the distal portion having a distal end, the catheter braid comprising a plurality of wire segments, each wire segment comprising: an outer shell having a first material composition; and an inner core extending through the outer shell and having a second material composition different from the first material composition over at least a portion of the length, the inner core having a first cross-sectional shape proximate the proximal end and a second cross-sectional shape proximate the distal end, the first cross-sectional shape transitioning to the second cross-sectional shape along the length, and wherein: (a) the second cross-sectional shape is different from the first cross-sectional shape; and / or (b) the inner core comprises a first metal composition proximate the proximal end and a second metal composition proximate the distal end, wherein the second metal composition is different from the first metal composition.

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

3. The catheter braid of claim 2, wherein the first number of wefts per inch is between about 20 and about 45 and the second number of wefts per inch is between about 120 and 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. The catheter braid of claim 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 is substantially rectangular proximate the proximal portion and gradually transitions to substantially circular proximate the distal portion.

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

7. The catheter braid of claim 1, wherein the inner core is hollow at the distal end of the distal portion.

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

9. The catheter braid of claim 8, wherein the first metal composition has a greater stiffness than the second metal composition.

10. The catheter braid of claim 8, wherein the outer shell comprises an upper half cylinder relative to a longitudinal axis and a lower half cylinder relative to the longitudinal axis.

11. The catheter braid of claim 10, wherein the inner core comprises a first metal, the upper half-cylinder comprises a second metal, and the lower half-cylinder comprises a third metal, the third metal having a greater density than the first and second metals, and the first metal having a greater density than the second metal.

12. The catheter braid of claim 10, wherein the upper half-cylinder comprises one or more air channels.

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

14. The catheter of claim 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 claim 13, wherein the second inner core of each segment of the second plurality of segments is hollow proximate a distal end of the distal portion.

16. A catheter braid disposed along a length of a catheter, the catheter braid comprising: a proximal portion comprising segments having a first cross-sectional shape, the first cross-sectional shape being substantially rectangular; and a distal portion comprising segments having a second cross-sectional shape, the second cross-sectional shape being substantially circular.

17. The catheter braid of claim 16, wherein the proximal portion has a smaller number of picks per inch than the distal portion.

18. The catheter braid of claim 16, further comprising a transition portion disposed between the proximal portion and the distal portion, the transition portion having a greater number of picks per inch than the proximal portion and a smaller number of picks per inch than the distal portion.

19. The catheter braid of claim 18, wherein the transition portion extends a length of between about 5 centimeters and about 15 centimeters and has a variable cross-sectional shape that is substantially rectangular proximate the proximal portion and substantially circular proximate the distal portion.

20. The catheter braid of claim 18, wherein the proximal portion has a number of picks per inch of between about 20 and about 50, the transition portion has a number of picks per inch of between about 50 and about 90, and the distal portion has a number of picks per inch of between about 110 and about 200. ​

Images