Intravascular device having an enhanced one-beam cutting pattern

Abstract

An intravascular device is disclosed having a reinforced one-beam cutting pattern. The elongated member includes a plurality of windows defining a plurality of axially extending beams interspersed among a plurality of circumferentially extending rings. The beams are formed using a dual-pass cutting method in which a blade makes two rotationally offset cutting passes at a given longitudinal position of the elongated member. The resulting beam has a reinforced structure that avoids excessively sharp edges and minimizes structural weaknesses.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0001] This application claims priority to U.S. Patent Application No. 16 / 855,366, filed on April 22, 2020, entitled "INTRAVASCULAR DEVICE WITH ENHANCED ONE - BEAM CUT PATTERN", which claims priority and benefit to U.S. Provisional Patent Application No. 62 / 842,216, filed on May 2, 2019, entitled "INTRAVASCULAR DEVICE WITH ENHANCED ONE - BEAM CUT PATTERN", the entire contents of each of which are incorporated herein by reference in their entirety.

Background Art

[0002]

[0002] Interventional devices such as guidewires and catheters are frequently used in the medical field to perform delicate procedures deep within the body. Typically, a catheter is inserted into a blood vessel in a patient's thigh, radial artery, carotid artery, or jugular vein and guided through the patient's vasculature to the heart, brain, or other target tissue as needed. In many cases, a guidewire is first sent to the target tissue, and subsequently one or more catheters are passed over the guidewire and sent to the target tissue. Once in place, a catheter can be used to deliver drugs, stents, embolization devices, radiopaque dyes, or other devices or substances that treat the patient in the desired manner.

[0003]

[0003] In many applications, such interventional devices must be angled to reach the target tissue through the tortuous bends and curves of the vasculature pathway. For example, guiding a guidewire and / or catheter to a part of the neurovascular system requires passing through the internal carotid artery and other tortuous paths. Such interventional devices require sufficient flexibility, especially near their distal ends, to navigate such tortuous paths.

[0004]

[0004] In some cases, part of the device is microfabricated to enhance flexibility. For example, a guide wire can comprise an outer elongate tube with a series of windows machined mechanically near the distal end and sometimes at other locations. The cuts are typically arranged to define a series of axially extending "beams" that connect a series of circumferentially extending "rings".

[0005]

[0005] Such microfabrication techniques are beneficial for enhancing the flexibility of elongate intravascular components, but some challenges remain. Therefore, improved intravascular devices and methods for manufacturing such devices have been continuously needed for many years.

Summary of the Invention

Means for Solving the Problems

[0006]

[0006] An intravascular device is disclosed that includes a guide wire and a microcatheter having an enhanced one-beam cutting pattern. The elongate member includes a plurality of windows that define a plurality of axially extending beams interspersed between a plurality of circumferentially extending rings. The beams are formed using a dual-path cutting method in which the blade makes two cutting paths offset in the rotational direction at each longitudinal position of the elongate member. The beams thus obtained have enhanced structural features that avoid overly sharp edges and minimize structural weaknesses.

[0007]

[0007] In one embodiment, the intravascular device includes an elongate member extending between a proximal end and a distal end along a longitudinal axis, the elongate member having a plurality of windows that define a plurality of axially extending beams and circumferentially extending rings. At least one beam has an inner surface, an outer surface, and a pair of side surfaces, and the angle formed between the inner surface and one or both of the side surfaces is less than 135°.

[0008]

[0008] In one embodiment, a method of manufacturing an intravascular device includes: preparing a single piece of stock material; inserting a blade into the stock material without completely penetrating the stock material to form a first cut in the stock material, wherein the blade is oriented such that the cutting edge is substantially perpendicular to the longitudinal axis of the stock material; rotating the stock material relative to the blade without advancing the stock material longitudinally relative to the blade; and inserting the blade into the stock material to form a second cut.

[0009]

[0009] It should be understood that both the foregoing general description and the following detailed description of the invention are exemplary and explanatory only and are intended to further explain the claimed invention.

Brief Description of the Drawings

[0010]

[0010] Various objects, features, characteristics, and advantages of the present invention will become apparent from the following description of the invention in conjunction with the accompanying drawings and the appended claims, and will be more readily understood. All of these form a part of this specification, and like reference numerals indicate corresponding parts of the various drawings, and the various elements described are not necessarily drawn to scale.

Figure 1

[0011] An exemplary intravascular device such as a guidewire or microcatheter is shown.

Figure 2

[0012] The distal end of one embodiment of an intravascular device configured as a guidewire is shown.

Figure 3

[0013] An elongate member having a one-beam cutting pattern is shown.

Figure 4

[0014] A typical process for forming a one-beam cutting pattern in a single piece of stock material is shown.

Figure 5

[0015] FIG. 5A shows the structure of the beam obtained from the standard cutting procedure shown in FIG. 4.

[0011] Figure 5B shows the structure of the beam obtained from the standard cutting procedure shown in FIG. 4.

Figure 6A

[0016] An alternative cutting procedure is shown.

Figure 6B

Figure 6C

[0012] Overview of the Intravascular Device

[0017] FIG. 1 shows an exemplary intravascular device 100 comprising an elongate member 104 extending between a proximal end 106 and a distal end 108. Any handle / hub / torque 102 can be attached to the proximal end 106. The elongate member 104 can be, for example, a guide wire or a microcatheter.

[0013]

[0018] The elongate member 104 can comprise a plurality of windows cut into its outer surface. The windows can be formed by cutting one or more pieces of stock material to form a cutting pattern that leaves the windows. The windows can provide various advantages, including enhancing the flexibility of the elongate member 104. In some embodiments, the windows are configured to provide improved flexibility (compared to a similar section of stock material without windows) while maintaining sufficient outer peripheral structure to effectively transmit torque.

[0014]

[0019] The elongate member 104 may be of any length necessary to advance through a patient's tissue to reach the target tissue region. A typical length may be, for example, in the range of about 50 to 300 cm. In catheter embodiments, the outer diameter of the elongate member 104 may be in the range of about 0.0254 cm (0.010 inches) to about 0.381 cm (0.150 inches), although larger or smaller diameters may be utilized depending on preferences and / or application needs. In guidewire embodiments, the outer diameter of the elongate member 104 may be about 0.03556 cm (0.014 inches), or may be in the range of about 0.02032 cm (0.008 inches) to about 0.3683 cm (0.145 inches), although larger or smaller sizes may be utilized depending on preferences and / or application needs.

[0015]

[0020] In catheter embodiments, the elongate member 104 is typically formed from a material having a modulus of elasticity of about 3000 MPa to about 4500 MPa, or about 3500 MPa to about 4000 MPa. In one exemplary embodiment, the elongate member 104 is formed from or includes polyetheretherketone (PEEK). Other polymers having higher moduli of elasticity may be utilized if permitted by cost and / or manufacturing considerations. In some embodiments, the elongate member 104 includes or is formed from a nickel-titanium alloy having superelastic properties at body temperature. In some embodiments, at least a portion (e.g., the proximal portion) of the elongate member 104 is formed from stainless steel or other materials having similar stress-strain and modulus of elasticity characteristics. Typically, when the elongate member 104 is formed from two or more different materials, the higher modulus of elasticity material is used in the more proximal section and the lower modulus of elasticity material is used in the more distal section.

[0016]

[0021] Figure 2 shows the distal end of one embodiment of an intravascular device configured as a guidewire 200. The embodiment shown in Figure 2 can represent the distal end 108 of the guidewire embodiment of the elongate member 104 of Figure 1. The embodiment shown in Figure 2 includes an inner member configured as a core 212. Other embodiments can include, additionally or alternatively, one or more other inner members, such as one or more inner tube structures.

[0017]

[0022] The illustrated guidewire 200 includes a core 212 and a tube structure 214 coupled to the core 212. As shown, the distal section 221 of the core 212 extends into and is surrounded by the tube 214. In some embodiments, the distal section 221 of the core 212 is ground to taper progressively to a smaller diameter (e.g., about 0.00508 cm (0.002 inches)) at the distal end. The distal section 221 of the core 212 can have a round cross-section, a rectangular cross-section, or other suitable cross-sectional shape. In this example, the core 212 and the tube 214 have substantially similar outer diameters at the attachment point 213 where they are attached adjacent to each other.

[0018]

[0023] The tube 214 can be coupled to the core 212 (e.g., using an adhesive, soldering, and / or welding) such that torsional forces are transmitted from the core 212 to the tube 214 and thereby further transmitted distally by the tube 214. A medical grade adhesive 220 can be used to couple the tube 214 to the core 212 at the distal end of the device to form a non-traumatic coating.

[0024] The guidewire 200 can further include one or more coils, such as coil 224, disposed within the tube 214 such that the coil is disposed between the outer surface of the distal section of the core 212 and the inner surface of the tube 214. The coil 224 may be formed from a radiopaque material such as platinum. The illustrated coil 224 is formed as a single integral part. In alternative embodiments, the coil 224 comprises a plurality of separate sections that are laminated, disposed adjacent to each other, and / or intertwined and connected together.

[0019]

[0025] The tube 214 can comprise a microfabricated window configured to provide effective flexibility and torquability of the intravascular device. Some embodiments can additionally or alternatively comprise a notch formed in the core 212 itself, for example along the distal section 221 of the core.

[0020] Standard one-beam cutting pattern

[0026] FIG. 3 shows an elongate member 900 having a plurality of beams 932 and rings 934. The elongate member 900 is an example of a one-beam cutting pattern because a single beam 932 is disposed between each pair of adjacent rings 934. In this example, each successive beam is rotated approximately 180° from the previous beam 932 and offset. In other embodiments, different rotational offset patterns may be used, or the rotational offset may be omitted such that the beams are aligned on one side of the elongate member 900.

[0021]

[0027] In some embodiments, the beams 932 can be arranged in a "helical" pattern, or a non-linear pattern such as a "dispersed" pattern, an "incomplete ramp" pattern, a "serrated" pattern, or combinations thereof, respectively, in different sections of the elongate member 900. These cutting patterns are described in more detail in PCT International Application No. PCT / US2018 / 034756, published as International Publication No. WO 2018 / 218216 A1, which is hereby incorporated by reference in its entirety.

[0022]

[0028] In some embodiments, the rings and beams of the intravascular device can be encapsulated in a polymer. Intravascular devices including guidewires and microcatheters having polymer-encapsulated microfabricated structures are described in further detail in U.S. Patent Nos. 9,067,332, 9,950,137, 9,067,333, and 9,072,873, each of which is hereby incorporated by reference in its entirety.

[0023]

[0029] FIG. 4 shows a typical process of forming a single-beam cut pattern in a piece of stock material 302. The stock material 302 (typically a tube structure) is placed in a cutting machine having a blade 304 (or multiple blades). As shown by arrow 306, the blade 304 is movable along an axis perpendicular to the longitudinal axis of the stock material 302 to form a window 303. The blade 304 is shown here as moving up and down along a vertical axis, although other configurations may have a blade (or multiple blades) that move along a horizontal axis or even a diagonal axis.

[0024]

[0030] To make the cuts, the blade 304 is brought into contact with the stock material 302 and can cut to a desired depth, and as a result, is moved inward until a beam 310 remains in the stock material 302. The blade 304 is then withdrawn from the stock material 302. Next, the stock material 302 is moved longitudinally relative to the blade 304 until the next desired cutting position is aligned with the blade 304, as shown by arrow 308. This process can then be repeated to form a desired number of cuts.

[0025]

[0031] The depth of the cuts and / or the spacing between the cuts can be varied from device to device or even from section to section of the same device. For example, a section intended to form the distal portion of an intravascular device can have relatively deep and / or relatively small spaced cuts to increase the relative flexibility at the distal portion.

[0026]

[0032] In some embodiments, such as embodiments forming helical or non-linear patterns, the stock material 302 may be rotated between successive cuts or between sets of successive cuts to allow for a rotational offset in the resulting beam, as indicated by arrow 312. Further details related to the cutting machine and associated manufacturing methods are described in U.S. Patent No. 10,232,141, which is hereby incorporated by reference in its entirety.

[0027]

[0033] Figures 5A and 5B show in more detail the structure of the beam 310 obtained from the standard cutting procedure shown in Figure 4. Figure 5A shows a front cross-sectional view of the stock material 302 along a line running parallel to the blade path of a particular cut, and Figure 5B shows an enlarged view of an edge section of the resulting beam 310. As shown, the blade 304 typically has a diameter significantly larger than the diameter of the stock material 302 (a typical blade diameter may range, for example, from 5.08 to 10.16 cm (2 to 4 inches)). Figure 5A shows the blade 304 at the deepest point within the stock material 302. After the blade 304 is withdrawn, the resulting beam 310 remains.

[0028]

[0034] As best shown in Figure 5B, the resulting beam 310 includes an inner surface 320, an outer surface 322, and two side surfaces 324 (only one is shown in Figure 5B). Each side surface 324 connects to the inner surface 320 along an internal edge 326 and to the outer surface 322 along an external edge 328. An angle 330 is formed where the inner surface 320 connects to the side surface 324.

[0029]

[0035] Due to the geometry of the notch, angle 330 is significantly larger than 90°, typically about 135°. As a structural result of the size of angle 330, the radial thickness of beam 310 decreases from inner edge 326 towards outer edge 328. "Radial thickness" means the thickness of the beam along a radial line extending from the geometric center of the cross-section of the tube structure 302 to the outer surface 322. Thus, beam 310 has a substantially uniform radial thickness over most of its circumferential length (as indicated by radial line 332a), but the radial thickness tapers (as indicated by progressively shorter radial lines 332b and 332c) between inner edge 326 and outer edge 328.

[0030]

[0036] Another structural result of edge 328 is that it is relatively "sharp". That is, the angle 331 formed between side surface 324 and outer surface 322 is relatively small, such as about 45° or less.

[0031] Reinforced single-beam cutting pattern

[0037] Figures 6A through 6C show an alternative method of forming beam 410 in a section of stock material 402. As shown in Figure 6A, blade 404 first passes through stock material 402 at a relatively short depth compared to the standard notch shown in Figure 5A. For example, if the standard notch shown in Figure 5A typically has a depth of about 70% or more of the diameter of the stock material, the depth of the first notch shown in Figure 6A is about 50% (e.g., from about 30% to about 70%).

[0032]

[0038] After the initial cut is formed, as shown in FIG. 6B, the stock material 402 is rotated relative to the blade 404 such that the blade 404 passes through the stock material 402 a second time. The stock material 402 maintains the same longitudinal position relative to the blade between the first and second passes of the blade 404 such that the second cut is in the same plane as the first cut. During the first cut, a first side surface 424a is formed and a temporary side surface 424c is formed. Next, the temporary side surface 424c is removed by the second cut and additional material is cut to form the second side surface 424b.

[0033]

[0039] In the sequence from FIG. 6A to FIG. 6B, the blade 404 appears to rotate clockwise relative to the stock material 402, but this is for exemplary convenience only, and it will be understood that any suitable means of relative rotation between the stock material 402 and the blade 404 can be utilized by rotating the blade 404, the stock material 402, or both. Typically, the stock material 402 is rotated relative to a rotatably stationary blade 404. The relative rotation is preferably about 90° (e.g., from about 60° to about 120°, or from about 75° to about 105°).

[0034]

[0040] FIG. 6C shows an enlarged view of an edge section of the resulting beam 410. The resulting beam 410 includes an inner surface 420, an outer surface 422, and a pair of side surfaces 424 (here only a single side surface 424b is shown). Each side surface 424 connects to the inner surface 420 along an inner edge 426 and to the outer surface 422 along an outer edge 428. An angle 430 is formed where the inner surface 420 connects to the side surface 424.

[0035]

[0041] Compared with the angle 330 of the beam 310 shown in FIG. 5B, the angle 430 of the beam 410 is significantly smaller. For example, the angle 430 can have a value within a range having a lower endpoint of about 75°, 80°, 85°, or 90° and an upper endpoint of about 130°, 120°, 110°, or 100°. Most preferably, the angle 430 is about 90° such that the side surface 424b is substantially perpendicular to the inner surface 420.

[0036]

[0042] The structure of the beam 410 provides a significant improvement compared to the standard beam 310. For example, the beam 410 avoids the "sharp" external edge 428 present in the standard beam 310. That is, the angle 431 formed between the side surface 424 and the outer surface 422 is greater than about 45°, for example, from about 50° to about 90°.

[0037]

[0043] The improved beam 410 also avoids the tapered profile of the standard beam 310 and has a more uniform radial thickness over the circumferential length of the beam 410. This advantageously minimizes structural weaknesses and results in a longer fatigue life for the beam 410.

[0038]

[0044] The dual-pass cutting process has surprisingly been found to improve manufacturing efficiency and yield compared to the standard single-pass process. Even though the number of blade passes is doubled, the dual-pass process results in a smaller depth per cut and typically forms a more accurate cut. It has been found that this more than compensates for the time required to make two cuts per beam.

[0039] Additional Exemplary Embodiments

[0045] The following are selected from exemplary embodiments of the disclosed intravascular devices and related methods. These are presented as merely examples and are not intended to limit the scope of the invention in any way.

[0040]

[0046] Embodiment 1: An intravascular device comprising an elongate member extending between a proximal end and a distal end along a longitudinal axis, wherein the elongate member has a plurality of windows defining a plurality of axially extending beams and circumferentially extending rings. At least one beam has an inner surface, an outer surface, and a pair of side surfaces, and the angle formed between the inner surface and one or both of the side surfaces is less than 135°.

[0041]

[0047] Embodiment 2: The device according to Embodiment 1, wherein the angle is from about 75° to about 130°.

[0048] Embodiment 3: The device according to Embodiment 1 or 2, wherein the angle is from about 80° to about 120°, or from about 85° to about 110°, or from about 90° to about 100°, or the angle is about 90°.

[0042]

[0049] Embodiment 4: The device according to any one of Embodiments 1 to 3, wherein the elongate member is a tube structure.

[0050] Embodiment 5: The device according to Embodiment 4, further comprising a core disposed within the tube structure.

[0043]

[0051] Embodiment 6: The device according to Embodiment 4 or Embodiment 5, further comprising an inner tube disposed within the tube structure.

[0052] Embodiment 7: The device according to any one of Embodiments 4 to 6, further comprising one or more coils disposed within the tube structure, the one or more coils optionally including one or more radiopaque coils.

[0044]

[0053] Embodiment 8: The device according to any one of Embodiments 1 to 7, wherein the elongate member comprises a polymer.

[0054] Embodiment 9: The device according to any one of Embodiments 1 to 8, wherein the rings and beams are encapsulated in a polymer.

[0045]

[0055] Embodiment 10: The device according to any one of Embodiments 1 to 9, wherein the elongated member comprises a nickel-titanium alloy.

[0056] Embodiment 11: The device according to any one of Embodiments 1 to 10, wherein the elongated member comprises stainless steel.

[0046]

[0057] Embodiment 12: The device according to any one of Embodiments 1 to 11, wherein the elongated member is formed from two or more different materials.

[0058] Embodiment 13: The device according to any one of Embodiments 1 to 12, wherein at least one beam has a substantially uniform thickness over its circumferential length.

[0047]

[0059] Embodiment 14: The device according to any one of Embodiments 1 to 13, wherein the angle formed between the outer surface and one or both of the side surfaces is greater than about 45°.

[0060] Embodiment 15: The device according to any one of Embodiments 1 to 14, wherein the intravascular device is a guide wire.

[0048]

[0061] Embodiment 16: The device according to any one of Embodiments 1 to 15, wherein the intravascular device is a microcatheter.

[0062] Embodiment 17: An intravascular device comprising an elongated member extending between a proximal end and a distal end along a longitudinal axis, the elongated member having a plurality of windows defining a plurality of axially extending beams and a circumferentially extending ring. At least one beam comprises an inner surface, an outer surface and a pair of side surfaces, and the angle formed between the inner surface and one or both of the side surfaces is from about 75° to about 130°, and the angle formed between the outer surface and one or both of the side surfaces is greater than about 45°.

[0049]

[0063] Embodiment 18: A method for manufacturing an intravascular device as described in any one of Embodiments 1 to 17, comprising the steps of: preparing a single piece of stock material; inserting a blade into the stock material without completely penetrating the stock material to form a first cut in the stock material, wherein the blade is oriented such that the cutting edge is substantially perpendicular to the longitudinal axis of the stock material; rotating the stock material relative to the blade without advancing the stock material longitudinally relative to the blade; and inserting the blade into the stock material to form a second cut.

[0050]

[0064] Embodiment 19: The method according to Embodiment 18, wherein the stock material is rotated about 60° to about 120° relative to the blade.

[0065] Embodiment 20: The method according to Embodiment 18 or Embodiment 19, wherein the first cut is made by inserting the blade into the stock material to a depth of about 30% to about 70% of the diameter of the stock material.

[0051]

[0066] Embodiment 21: The method according to any one of Embodiments 18 to 20, wherein the second cut is made by inserting the blade into the stock material to a depth of about 30% to about 70% of the diameter of the stock material.

[0052] Conclusion

[0067] While specific embodiments of the present disclosure have been described in detail with reference to specific configurations, parameters, components, elements, etc., this description is illustrative and should not be construed as limiting the scope of the claimed invention.

[0053]

[0068] Furthermore, for any given element of a component of the described embodiments, it should be understood that any of the possible alternatives listed for that element or component may generally be used alone or in combination with each other, unless otherwise implicitly or explicitly stated otherwise.

[0054]

[0069] In addition, unless otherwise indicated, it should be understood that any numbers used in this specification and the claims to represent amounts, components, distances, or other measurements are optionally modified by the term "about" or its synonyms. Terms such as "about", "approximately", "substantially", etc., when used in combination with a recited amount, value, or condition, may be construed to mean an amount, value, or condition that deviates by less than 20%, less than 10%, less than 5%, or less than 1% from the recited amount, value, or condition. Without intending to limit the application of the doctrine of equivalents to the claims, each numerical parameter should be construed in light of the reported number of significant digits and by applying ordinary rounding methods.

[0055]

[0070] Any headings and subheadings used herein are for organizational purposes only and are not meant to limit the specification or the claims.

[0071] Furthermore, it should also be noted that when used in this specification and the appended claims, the singular forms "a", "an", and "the" do not exclude a plurality of referents unless the context clearly dictates otherwise. Thus, for example, embodiments that refer to a singular referent (e.g., "widget") can include two or more such referents.

[0056]

[0072] Also, it will be understood that the embodiments described herein can have the characteristics, features (e.g., components, parts, members, elements, portions, and / or sub - portions) described in other embodiments described herein. Thus, the various features of a given embodiment can be combined with and / or incorporated into other embodiments of the disclosure. Accordingly, the disclosure of a particular feature in relation to a particular embodiment of the disclosure should not be construed as limiting the application or incorporation of the above - mentioned feature to that particular embodiment. Rather, it will be understood that other embodiments can also include such features.

Claims

**Claim 1** A method for manufacturing an intravascular device, comprising: preparing a single piece of stock material; inserting a blade into the stock material without completely penetrating the stock material to form a first cut in the stock material, wherein the blade is oriented such that the cutting edge is substantially perpendicular to the longitudinal axis of the stock material; rotating the stock material relative to the blade without advancing the stock material longitudinally relative to the blade; inserting the blade into the stock material to form a second cut, wherein the first cut and the second cut form a single axially extending beam disposed between a pair of adjacent circumferentially extending rings; and a method comprising the steps of. **Claim 2** The method of claim 1, wherein the stock material is rotated about 60° to about 120° relative to the blade. **Claim 3** The method of claim 1, wherein the first cut is made by inserting the blade into the stock material to a depth of about 30% to about 70% of the diameter of the stock material. **Claim 4** The method of claim 3, wherein the second cut is made by inserting the blade into the stock material to a depth of about 30% to about 70% of the diameter of the stock material.

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