CN118251253A - Intravascular Guidewire and Microcatheter Systems - Google Patents

Abstract

A guidewire and catheter system are disclosed that can be used to facilitate a desired catheter axial response (e.g., pushability) on the guidewire for advancement through a patient's vasculature. The features of the guidewire and catheter system enable the catheter to be advanced over the guidewire in a tortuous path of the patient's vasculature in response to a push force of no more than 50 g. The constructed catheter device may be advanced over a guidewire within the tortuous path of the patient's vasculature in response to a 50g or less push force. For example, using a tortuous path model with a total path length of 21.5cm, an inner diameter of 3.68mm, with three complete loops, the guidewire and catheter system can be advanced over the guidewire without exceeding 30 grams of thrust.

Description

Intravascular Guidewire and Microcatheter Systems

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Utility Application No. 17/901,819, filed on September 1, 2022, entitled “Intravascular Guidewire and Microcatheter System,” U.S. Provisional Application No. 63/271,114, filed on October 22, 2021, entitled “Intravascular Guidewire and Microcatheter System,” and U.S. Provisional Application No. 63/240,845, filed on September 3, 2021, entitled “Microcatheter Device with Non-Linear Bending Stiffness,” and the entire contents of each of the foregoing applications are incorporated herein by reference in their entirety.

Background Art

Interventional devices, such as guidewires and catheters, are often used in the medical field to perform delicate procedures deep inside the human body. Typically, a catheter is inserted into a patient's femoral, radial, carotid, or jugular blood vessel and guided through the patient's vasculature to the heart, brain, or other target anatomical structures via a guidewire. Once in place, the catheter can be used to deliver drugs, stents, embolic devices, radiopaque dyes, or other devices or substances for treating the patient in a desired manner.

In many applications, such an interventional device must be guided through the tortuous bends and bends of a vascular system passage to reach the target anatomical structure. Such an interventional device (especially near its distal end) needs to be flexible enough to guide such a tortuous path. However, other design aspects must also be considered. For example, the interventional device must also be able to provide sufficient torsionability (i.e., the ability to transmit torque applied at the proximal end all the way to the distal end), pushability (i.e., the ability to transmit axial thrust to the distal end rather than the bending and constraining middle portion), and structural integrity for performing the intended medical function.

It is desirable that the catheter device has a good axial response, so that when a thrust is applied to the proximal end of the catheter device located on the guide wire (e.g., in the patient's vascular system), the middle portion and the distal portion of the catheter device advance on the guide wire (e.g., further into the patient's vascular system) according to the thrust. However, typically, when the catheter device advances in the bends and flexures of the vascular system, most of the axial movement will incidentally push the middle portion of the device into the wall of the flexure of the vascular system, rather than actually advancing the distal end of the catheter device. This lack of correspondence between the amount of axial push provided by the user at the proximal end and the forward movement of the distal end makes guidance more difficult and less intuitive in terms of touch.

Thus, several limitations exist in the art of guidewire and catheter systems, and there is a continuing need for systems that can effectively advance a catheter over a guidewire within the vasculature without requiring excessive pushing force to reach a desired anatomical target.

BRIEF DESCRIPTION OF THE DRAWINGS

Various objects, features, characteristics and advantages of the present invention will become apparent and more easily understood from the following description of the embodiments in conjunction with the accompanying drawings and the appended claims, all of which constitute a part of this specification. In the drawings, similar reference numerals may be used to indicate corresponding or similar parts in the various drawings, and the various elements depicted are not necessarily drawn to scale, wherein:

FIG1 shows an overview of a catheter system, including a catheter and a hub;

FIG. 2 shows a detailed view showing various cross sections of a catheter of the catheter system;

3A-3C illustrate examples of single beam segments, dual beam segments, and triple beam segments, respectively, that may be included in a microfabricated shaft for use in the catheter systems described herein;

FIG4 shows a detailed view of the distal section of the catheter;

5A to 5D are photographs showing differences in axial response that can occur within a blood vessel (artificial blood vessel shown), wherein FIGS. 5A and 5B show the axial response of a conventional catheter, and FIGS. 5C and 5D show the improved axial response of a catheter according to the present disclosure;

FIG6 schematically illustrates a cross-section of a catheter during bending, showing how the catheter is configured to distribute bending, torsional, and axial forces in a tortuous anatomical structure;

7A and 7B show a microfabricated shaft configured to compensate for a step change in stiffness in an outer polymer layer due to a transition from one polymer to another;

8A and 8B compare the bending stiffness profile of a catheter device according to the present disclosure (labeled "Plato 17") with the bending stiffness profiles of various conventional catheter devices, wherein FIG. 8A shows the bending stiffness up to 60 cm from the distal tip and FIG. 8B shows the bending stiffness up to 15 cm from the distal tip;

FIG. 9 compares the outer diameter along the distal length of a catheter device according to the present disclosure (labeled “Plato 17”) with various conventional catheter devices;

FIG10 illustrates an exemplary embodiment of a guidewire device that provides effective torquability and has a formable tip;

FIG11 is a cross-sectional view of the guidewire device of FIG10 ;

FIG12 illustrates an exemplary embodiment of a tube structure that may be used with the guidewire device of FIGS. 10 and 11 , the tube having a bypass cut pattern (i.e., a single beam cut pattern) configured to provide effective flexibility and formability of the distal tip;

FIG13 shows an alternative embodiment of a tube structure including segments having an alternative single beam cutout pattern;

FIG14 illustrates an embodiment of a tube structure including a dual beam cutout pattern with symmetrically spaced opposing beams;

FIG15 shows an embodiment of a tube structure including a segment having a single-sided single beam cutout pattern;

FIG. 16 illustrates an embodiment of a tube structure including a bypass cut pattern having an exemplary angular offset providing a helical pattern of the resulting beam;

FIG17 shows a perspective view of an embodiment of a tube structure comprising three sections;

FIG18A illustrates a side view of an embodiment of a tube including a distal segment of a core disposed therein;

FIG. 18B shows a cross-sectional view of the tube of FIG. 18A ;

FIG. 19 shows an enlarged side view of the transition between the first and second sections of the tube of FIGS. 18A and 18B ; and

20 shows an enlarged side view of the distal tip of the tube of FIGS. 18A and 18B , including the second and third sections of the tube.

DETAILED DESCRIPTION

Overview of the combined system

As described above, many catheter devices lack correspondence between the application of proximal thrust and the advancement of the distal portion and the middle portion (for example, when the catheter device is positioned above the guidewire in the curved portion of the patient's vascular system). Conventional catheter devices typically utilize a variety of different materials to provide a bending stiffness gradient from the proximal end to the distal end. However, whenever there is a transition between materials of different stiffness, the bending stiffness distribution, axial stiffness distribution, and torsional stiffness distribution of the device include sudden step changes. Such sudden changes in bending stiffness are undesirable because they can concentrate mechanical stresses at specific locations, cause kink points, destroy the smooth movement and bending of the device, and complicate guidance in tortuous vascular systems. Such sudden changes in bending stiffness can lead to the lack of correspondence between the above-mentioned proximal thrust and the distal advancement.

When faced with a situation where applying excessive proximal thrust (e.g., greater than about 30 grams to 50 grams) fails to adequately promote further advancement of the catheter device over the guidewire within the patient's vasculature, medical practitioners typically withdraw the catheter (and sometimes the guidewire) to re-attempt routing of the guidewire and/or catheter through the patient's vasculature to the target. Such events result in inefficiencies related to time and materials and may adversely affect patient outcomes.

Therefore, at least one aspect of the present disclosure is to provide a guide wire and a catheter system, which can be used to promote the desired catheter axial response (e.g., shoveability) to advance through the patient's vascular system (or through the environment of a simulated patient's vascular system). At least some of the example guide wires and catheter systems discussed herein present a smooth bending stiffness distribution along the length of the device, thereby contributing to reducing the concentration of mechanical stress at a specific location. These features can make the catheter device of the present disclosure show shoveability, torsion and/or bending flexibility features, thereby allowing the catheter device to advance on the guide wire in a manner that reduces the axial force loss to the vascular system wall, and contribute to effectively (with minimal thrust) advancing to a predetermined target.

The catheter device constructed according to the present disclosure can advance on the guide wire in the tortuous path of the patient's vascular system in response to 50g or lower thrust.For example, for a total path length of 21.5cm, an internal diameter of 3.68mm, an example tortuous path model with three complete loops (each loop radius is 6.4mm), the guide wire and catheter system constructed according to the present disclosure can advance on the guide wire when being no more than 30 grams of thrust (no more than 20 grams of thrust in some cases).Especially, the catheter/guide wire system with 0.017 inch (internal diameter) catheter and 0.014 inch (external diameter) guide wire advances through the model when the thrust is no more than 18g, and the catheter/guide wire system with 0.027 inch (internal diameter) catheter and 0.024 inch (external diameter) guide wire advances through the model when the thrust is no more than 29g.

Other combinations of devices, such as the STRYKER SYNCHRO 2 used in conjunction with the STRYKER EXCELSIOR SL-10, failed to match this performance. In fact, the STRYKER SYNCHRO 2 and STRYKER EXCELSIOR SL-10 combined system could not pass the entire model even with an applied thrust of 50g (which jumped to a high of 200g).

The ratio of the model to the tested catheter is 557% (e.g., the inner diameter of the model is 3.68 mm, and the outer diameter of the catheter is 0.66 mm). The guidewire and catheter combinations of different sizes utilizing the structural features disclosed herein are also expected to perform similarly in models with similar size ratios. For example, as long as the ratio of the inner diameter of the model to the outer diameter of the catheter is about 250% to about 800%, or about 300% or 350% to about 750%, or about 400% to about 700%, or about 450% to about 650%, or about 500% to about 600%, or its ratio is within the endpoint range defined by any two of the aforementioned values, similar effective results can be expected.

Thus, the guidewire and catheter system of the present disclosure enables a medical practitioner to more efficiently advance a catheter to a predetermined target, reducing instances where a safe level of thrust fails to fully advance the catheter over the guidewire, thereby avoiding the inefficiencies associated with the withdrawal and/or re-advancement of the catheter device and/or guidewire device.

Experiments similar to those shown in Figures 5A to 5D have demonstrated that a catheter constructed in accordance with the present disclosure (e.g., including one or more features described with reference to catheter 102) is capable of advancing over a guidewire in a blood vessel in response to application of a thrust force of about 50 g or less, or about 40 g or less, or about 35 g or less, or about 30 g or less, or about 25 g or less, or about 20 g or less (e.g., within a range of about 10 g to about 20 g, or within a range of about 20 g to about 30 g, or within a range of about 30 g to about 40 g, or within a range of about 40 g to about 50 g, or within a range with any of the foregoing values as endpoints).

This functionality can be demonstrated by the catheter device of the present disclosure in an operating environment (e.g., a real blood vessel or a model blood vessel) having a path length of approximately 21.5 cm with bends and/or loops (e.g., 1 bend and/or loop, 2 bends and/or loops, 3 bends and/or loops, or more than 3 bends and/or loops) of various radii (e.g., in a range of approximately 3 mm to approximately 10 mm, such as 6.4 mm).

The disclosed system can be used for various vessel-catheter ratios. For example, the vessel inner diameter can be in the range of about 2mm to about 6mm (e.g., about 3.68mm), and the catheter outer diameter can be in the range of about 0.2mm to about 1.5mm (e.g., about 0.66mm), resulting in a vessel-catheter ratio in the range of about 133% to about 3,000% (e.g., about 371% or greater, such as 557% for a lumen inner diameter of 3.68mm and a catheter outer diameter of 0.66mm). The test model can use other sizes. Those skilled in the art will recognize that, as long as the same model conditions are used for each catheter/guidewire combination, various catheter/guidewire combinations can be effectively tested against each other using this test model. This thrust test is easily carried out within the capabilities of the technician.

Example Catheter Device

1 is an overview of an example catheter device 100 that includes features described in more detail below that provide one or more of: improved axial responsiveness, improved bending force distribution, and/or smooth device bending stiffness profile.

The catheter device 100 includes a catheter 102 connected to a hub 104 at a proximal end and extending from the hub 104 to a distal end 103. The catheter 102 can be coupled to the hub 104 using an adhesive, a friction fit, by insertion molding, and/or other suitable attachment means. A strain relief member 106 is also disposed on a proximal section of the catheter 102 near the hub 104. The strain relief member 106 has an outer diameter that substantially matches an adjacent section of the hub 104. The strain relief member 106 extends a distance from the hub 104 and has a substantially constant outer diameter before tapering distally to an end where the catheter 102 emerges and extends further distally. The strain relief member 106 can include a groove pattern 108 disposed at a section of substantially constant outer diameter for providing additional flexibility to the strain relief member 106 and/or providing surface features for enhancing user grip and tactile engagement.

The working length of the catheter 102 (i.e., the distance between the distal end of the strain relief (106) and the distal end (103) of the catheter (102)) can vary depending on the needs of a particular application. As an example, the catheter 102 can have a working length of about 50 cm to about 200 cm, although shorter or longer lengths can be used in appropriate circumstances. The catheter size (generally referred to as the inner diameter/lumen size) can also vary depending on the needs of a particular application. Examples include 0.010 inches, 0.013 inches, 0.017 inches, 0.021 inches, 0.027 inches, 0.030 inches, 0.035 inches, 0.038 inches, 0.045 inches, 0.065 inches, 0.085 inches, 0.100 inches, or a range including any two of the above values as endpoints. The inner diameter of the catheter can taper from a smaller distal portion to a larger proximal portion. In certain applications, smaller or larger sizes may be appropriately used.

In addition, the outer diameter of the catheter 102 can vary depending on the needs of a particular application. Examples include 0.010 inches, 0.013 inches, 0.017 inches, 0.021 inches, 0.026 inches, 0.027 inches, 0.030 inches, 0.035 inches, 0.038 inches, 0.045 inches, 0.065 inches, 0.085 inches, 0.100 inches, 0.135 inches, 0.165 inches, 0.20 inches, or a range including any two of the above values as endpoints.

Although the distal section of the catheter 102 is shown in this example as having a straight shape, other embodiments may include a shaped distal tip. For example, the distal section of the catheter 102 may have an angled shape, a curved shape (e.g., a 45 degree angle, a 90 degree angle, a J shape, etc.), a compound curved shape, or other suitable angled or curved shapes known in the art.

The catheter device 100 described herein can be used for a variety of interventional applications, most commonly for cardiovascular, peripheral vascular and neurovascular interventional procedures. Examples include access to distal anatomical structures, through vascular lesions or clots, ischemic treatment, delivery of therapeutic agents (e.g., embolic coils or other embolic agents), injection of diagnostic agents (e.g., contrast agents or saline), retrieval applications, aspiration applications, or other applications where the use of a microcatheter is beneficial.

The internal features of the catheter 102 will be described in more detail below. The outer surface of the catheter 102 can be coated with a suitable coating material, such as a hydrophilic coating, to make the surface smoother. The coating material can substantially cover the entire working length of the catheter 102 or a portion thereof. For example, the coating material can be applied to the most distal 30% to 80% of the working length of the catheter 102.

Fig. 2 shows a detailed view of the catheter 102, better showing some of the internal components and different longitudinal sections of the catheter 102. As shown, the catheter 102 includes an inner lining 110 that defines the internal lumen of the device. The lining 110 can be formed by polytetrafluoroethylene (PTFE) and/or other suitable polymers. The coil 114 is located on the line near the distal end 103. The coil 114 is attached to or positioned near a micro-fabricated shaft 112 (also referred to as "inner shaft" here), which extends proximally from the coil. An outer member 115 formed by one or more polymer materials is usually heat-shrink laminated on the coil 114 and the shaft 112 and passes through the coil 114 and the shaft 112, covering both and also being attached to the liner at the same time.

In one embodiment, the coil 114 is formed of stainless steel and the shaft 112 is formed of nitinol. These materials, when used in conjunction with the other features described herein, have been found to provide effective axial response, effective distribution of bending forces, and smooth bending stiffness distribution. Other embodiments may use one or more different materials for the coil 114, the shaft 112, or both. For example, in some embodiments, the shaft 112 may include other superelastic alloys and/or one or more polymers, such as polyetheretherketone (PEEK) or other polyaryletherketones (PAEK). In some embodiments, the coil 114 may include a superelastic alloy (such as nitinol), one or more other metals, alloys, or polymers.

Catheter 102 is configured to make the overall bending stiffness distribution transition from the higher stiffness (and less bending flexibility) at the proximal section to the lower stiffness (and greater bending flexibility) at the distal section. In most applications, it is desirable to give the proximal section of the device relatively high axial stiffness, torsional stiffness and bending stiffness so that they can provide a good combination of flexibility, pushability and torsionalness. However, the distal section is usually guided through a tortuous vascular system, so it is preferably relatively more flexible when bent. It is possible to coat the shaft 112 by adjusting certain features of the micro-fabricated shaft 112 and/or by utilizing different polymer materials and embed the shaft 112 in the external member 115 to produce this stiffness distribution gradient. As explained in more detail below, in some embodiments, the micro-catheter 112 and the external member 115 are configured to work together to provide an overall stiffness distribution that minimizes sudden changes in stiffness and provides a smooth stiffness transition.

The illustrated embodiment includes a distal section 120, an intermediate section 122, and a proximal section 124. In the distal section 120, the outer member 115 is formed of a first polymer material 116a. In the intermediate section 122, the outer member 115 is formed of a second polymer material 116b. In the proximal section 124, the outer member 115 is formed of a third polymer material 116c. The polymer materials 116a, 116b, and 116c have different hardnesses, thus affecting the stiffness of their respective sections differently. The second polymer material 116b has a higher hardness than the first polymer material 116a, and the third polymer material 116c has a higher hardness than the second polymer material 116b.

As an example of a group of polymer materials found to be effective when used together, the first polymer material 116a can have a Shore D hardness of about 20 to about 30, the second polymer material 116b can have a Shore D hardness of about 30 to about 50, and the third polymer material 116c can have a Shore D hardness of about 50 to about 80. Other embodiments can change these values as needed, such as being softer in the distal portion, but the above values have been found to be particularly effective. Polymer material 116a, polymer material 116b, and polymer material 116c can be independently formed of suitable polymers, such as polyether block amide (PEBA) polymers, and the range in the polymer hardness scale can be from about 10 Shore A hardness to about 100 Shore D hardness.

The shaft 112 also includes features that provide variable bending stiffness. As shown, the shaft 112 is a tube structure that includes a series of micro-machined cuts. The cuts form axially extending "beams" that connect continuous circumferentially extending "rings". These cut patterns can be changed to adjust the bending stiffness of the shaft 112. For example, the bending stiffness can be adjusted by adjusting the number of beams located between each pair of adjacent rings. A "double beam section" (such as shown in the distal section 120) includes two beams between each pair of adjacent rings. A "three beam section" (such as shown in the middle section 122 and the proximal section 124) includes three beams between each pair of adjacent rings. Under all other conditions being equal (shaft material, cut depth, cut width, cut spacing), the three beam section has greater bending stiffness than the double beam section. A "single beam section" in which a single beam connects adjacent rings can also be used, and under other conditions being equal, its bending stiffness is even smaller than the double beam section. "Four-beam sections" and/or sections having more than four beams may also be used, and will provide correspondingly greater bending stiffness as the number of beams between each pair of adjacent rings increases.

Figures 3A to 3C show examples of single beam sections, double beam sections, and triple beam sections, respectively, showing example arrangements of beams 130 and loops 132 in these sections. Depending on the angular offset (or lack of angular offset) between successive beam groups and/or how often the angular offset is applied (e.g., after each loop or after two or more loops), the beams can be configured into a variety of arrangements. For example, the single beam section of Figure 3A includes a 180 degree angular offset from one beam to the next beam, the double beam section of Figure 3B includes a 90 degree offset from a pair of beams to the next pair of beams, and the triple beam section of Figure 3C includes a 120 degree angular offset from one set of beams to the next set of beams. While these types of offsets are beneficial, they are also associated with a preferred bending plane, and other arrangements may be provided to minimize or eliminate the preferred bending plane. Examples include a spiral arrangement, a distributed arrangement, an imperfect ramp arrangement, and a sawtooth arrangement. Additional details regarding beam arrangements that may be used in the presently disclosed shaft 102 are provided in U.S. Patent No. 11,369,351 and U.S. Patent Application No. 2022/0105312, both of which are incorporated herein by reference in their entireties.

In addition to adjusting the number of beams disposed between the rings, the bending flexibility of the shaft 112 can be controlled by adjusting the depth of the cut, the width of the cut and/or the spacing of the cuts. Typically, the cut width is set to a given value (e.g., corresponding to the cutting blade size), and it is easier to adjust the cut depth and/or the cut spacing during the manufacturing process to provide the desired control of the bending stiffness distribution. Under other conditions being the same, when the ring width decreases (i.e., the cut spacing decreases), the cut width increases and/or the beam width decreases (i.e., the cut depth increases), the final bending stiffness decreases. In the illustrated embodiment, the spacing between the cuts in the three-beam section (consistent with the middle section 122 and the proximal section 124) gradually decreases as it approaches the distal section 120. Similarly, the double-beam section (consistent with the distal section 120) starts with a larger spacing between the cuts, and as it approaches the coil 114 and the distal end 103, the spacing between the cuts gradually decreases. Preferably, the transition between different geometries (e.g., three beams to two beams) is configured so that the bending stiffness is the same or similar across the transition between these sections. Thus, the shaft 112 provides a stiffness gradient by transitioning from a three beam section to a two beam section, and provides a stiffness gradient within the respective sections by transitioning from more widely spaced cuts to relatively closely spaced cuts.

At the distal end of the dual beam segment, the cut pattern is configured to have relatively high flexibility to provide a smooth transition to the high flexibility of coil 114. In some embodiments, coil 114 is omitted and replaced by more dual beam segments (or alternatively, single beam segments) extending to a position at or near distal end 103.

The lengths of the segments 120, 122, and 124 can vary depending on specific application requirements or preferences. In one embodiment, the distal segment 120 can have a length of about 5 cm to about 40 cm, the intermediate segment 122 can have a length of about 10 cm to about 50 cm, and the proximal segment 124 occupies the remainder of the working length of the catheter 102. The illustrated embodiment shows that the shaft 112 transitions from a three-beam configuration to a double-beam configuration at the transition from the intermediate segment 122 to the distal segment 120. However, the transition of the shaft 112 does not necessarily correspond to a transition of polymer materials defining independent segments 120, 122, and 124. As explained in more detail below, the shaft 112 and the outer member 115 are configured together to compensate for and minimize sudden stiffness changes, and in some cases, this may involve a shaft transition zone that does not completely overlap with the polymer transition of the outer member 115.

FIG4 shows a detailed view of the distal section 120 of the catheter 102, better showing certain distal features, such as the liner 110, the distal radiopaque marker band 140, the coil 114, the shaft 112, and the proximal radiopaque marker band 142. The marker bands 140 and 142 are formed of a material that is more radiopaque than stainless steel. Examples include platinum, iridium, tungsten, other highly radiopaque metals and alloys thereof. The distal marker band 140 provides an indication of the position of the distal end 103 of the catheter 102, while the proximal marker band 142 is offset by a predetermined length (e.g., 2 cm to 5 cm, or about 3 cm) to aid in the proper positioning of a detachable embolic coil or other component deployed through the catheter 102.

The shaft 112 may include a circumferential groove at the location where the proximal marker band 142 is placed. The groove is capable of receiving the marker band 142 so that the outer surface of the marker band 142 does not overextend beyond the outer diameter of the shaft 112. Once covered by the outer member 115, the outer diameter of the device on the proximal marker band 142 remains substantially flush.

In the illustrated embodiment, the coil 114 is of variable pitch. Each end of the coil 114 includes a region where the pitch narrows, which provides a further improved transition from a geometry to another geometry (such as at the position where the coil transitions to the micro-fabrication tube). For example, the coil 114 can have a length of about 1cm to about 3cm. As shown in the figure, a part of the liner 110 can extend a distance distally from the coil 114 and the distal marking coil 140. For example, the distance can vary from about 0.2mm to about 2mm.

Catheter bending force distribution

Catheter device as described herein includes the feature of effectively distributing bending force, thereby provides improved axial response in use. Fig. 5 A and Fig. 5 B show the common limitation that traditional catheter (STRYKER EXCELSIOR SL-10 shown in this example) is guided through artificial vascular system structure.When catheter approaches the bend in blood vessel, a certain length of catheter extends around bend (initial position in Fig. 5 A).When further promoting, before any continuous promotion causes the distal tip of catheter to actually advance through vascular system, initial axial movement is used to push catheter against vascular wall to fill flexure (after the pushing position in Fig. 5 B; see the contact point shown by the arrow).The correspondence between the amount of axial pushing provided by this user at the proximal end and the forward movement of the distal end caused is reduced, making guiding more difficult and not so intuitive in tactile sense.In addition, as mentioned above, in many cases, practitioners cannot apply additional thrust to overcome the resistance generated by vascular wall, because doing so will have the risk of injuring patients.

In contrast to the response of conventional catheters in Fig. 5A and Fig. 5B, Fig. 5C and Fig. 5D illustrate the use of catheter 102 as described herein to guide the bend of a blood vessel. As shown, from the "initial" position (Fig. 5C) to the position after advancement (Fig. 5D), less axial movement is used to fill the bend of the blood vessel, so more axial movement is converted into actual movement of the distal end of catheter 102. This function stems from the ability to distribute bending forces along the length of catheter 102. By better distributing bending forces, catheter 102 better resists bending at any one specific location, thereby being able to better transmit proximal axial movement to the distal end of the device.

FIG6 further illustrates the ability of the catheter 102 to effectively distribute bending forces. FIG6 illustrates a portion of the shaft 112 during bending. The polymer material 116 fills the gaps between the beams and rings of the shaft 112. For ease of viewing, the polymer material 116 is shown as discrete segments within each gap of the shaft 112. In most cases, the polymer material 116 will fill the gaps, fuse with the liner 110, and also extend over the outer surface of the shaft 112 to completely encapsulate and embed the shaft 112.

During bending of the shaft 112, the shaft structure locally resists more bending stress and distributes that stress more effectively to adjacent portions of the structure than a coil or braid that is less likely to distribute the bending stress and more likely to kink. In addition, the polymer material 116 effectively acts as a series of dampers, each located between adjacent loops of the shaft 112. On the inside of the bend, the polymer material 116 is compressed, thereby providing a reaction force that pushes the loops outward and resists further bending. Similarly, on the outside of the bend, the polymer material 116 is in tension, thereby providing a reaction force that pulls the loops inward and resists further bending. The bending stiffness of the catheter 102 is non-linear in that as the bend angle increases, the catheter 102 becomes increasingly resistant to bending in a non-linear manner.

During the bending process, a conventional catheter will begin to bend at the apex, and the cross-sectional shape of the catheter may tend to be "elliptical". Once ovalization begins, the bending resistance will decrease, so as the bending force continues to be applied, the catheter becomes increasingly easier to bend. In contrast, in the disclosed catheter 102, the bending resistance provided by the microfabricated structure and the action of the polymer material 116 on the shaft 112 tends to distribute the bending force along the axial length of the catheter 102 and avoid ovalization and concentration of the bending force at a specific kink point. For example, the bending resistance tends to expand the bend to a larger radius of curvature rather than concentrating the bend at a specific point, thereby creating a kink position. Therefore, the bending resistance provided by the catheter structure can provide enhanced axial responsiveness (as shown in Figures 5C and 5D), and also enhances protection against mechanical fatigue caused by bending stress.

Smoothing of the bending stiffness distribution of the catheter

7A and 7B illustrate that the microfabricated shaft can be configured to compensate for a step change in stiffness in the outer member due to a transition from one polymer to another. FIG. 7A shows a portion of the catheter 102 where a first polymer material 116a meets a second polymer material 116b. As shown in FIG. 7B , this is associated with an abrupt step change in the bending stiffness of the polymer layer of the outer member. Such abrupt changes in bending stiffness are undesirable because they can concentrate mechanical stresses, induce kink points, disrupt smooth movement and bending of the device, and complicate guidance in tortuous vasculature.

In order to compensate for this step change, the shaft is configured so that the bending stiffness change supplements and compensates for the sudden change in the bending stiffness of the polymer outer member. As a result, the overall bending stiffness of the catheter remains relatively smooth in the transition from the first polymer 116a to the second polymer 116b. Similar configurations can be used at other polymer transition zones to minimize and smooth the sudden step change in bending stiffness. . The shaft 112 can be configured to compensate for the step change in a variety of ways. In the example of FIG. 7A, because the bending stiffness of the second polymer 116b is higher than that of the first polymer 116a, the configuration of the cut/gap of the shaft 112 remains unchanged, or narrows over a short distance across the transition before unfolding again, so as to generally increase the shaft bending stiffness when moving further proximally. Other means of adjusting the bending stiffness of the shaft 112 as described herein (e.g., adjusting the number of beams and/or the depth of the cut) can be used additionally or alternatively to achieve a result of smoothing the overall bending stiffness distribution.

Configuring the shaft 112 to compensate for the sudden bending stiffness change of the polymer outer member 115 beneficially avoids the complexity of other traditional methods of smoothing this transition. Existing methods rely on complex splicing arrangements or polymer co-extrusion and mixing techniques. These add additional layers of complexity to the manufacturing process and may still only slightly address the abruptness of the transition. Other methods utilize polymer tubing of different diameters and diameter gradients to compensate for the transition between polymer types. However, these methods result in uneven outer diameters or increase the requirement to manage this situation in some way by stacking more material.

The smooth features described herein enable the manufacture of microcatheters with improved bending stiffness distributions compared to conventional microcatheters. FIGS. 8A and 8B show test results comparing the bending stiffness distribution of a catheter manufactured according to the present disclosure (labeled "Plato 17") with the bending stiffness distributions of several conventional microcatheters. In the figures, "SL10" refers to Excelsior SL-10 (sold by Stryker Neuralvascular), "XT17" refers to Excelsior XT-17 (sold by Stryker Neuralvascular), "Ech14" refers to Echelon 14 (sold by Medtronic), "Ech10" refers to Echelon 10 (sold by Medtronic), and "HW17" refers to Headway 17 (sold by MicroVention Terumo). FIG. 8A shows the bending stiffness distribution of the distal 50 cm to 60 cm of the device, and FIG. 8B provides a closer view of the bending stiffness distribution of the distal 15 cm of the device. In the figure, Plato 17 data represents the average of 5 repetitions, SL10 data represents the average of 3 repetitions, XT17 represents the average of 2 repetitions, Ech14 represents the average of 2 repetitions, Ech10 represents the average of 3 repetitions, and HW17 represents the average of 2 repetitions. As shown in the figure, the catheter corresponding to the present disclosure provides a smoother distribution with less abrupt changes in bending stiffness.

Table 1 presents the data of Figures 8A and 8B by listing the different distal segment dimensions and providing the highest measured "slope" within that segment. The "slope" represents the change in bending stiffness (N·m ² ) over the distance (cm) between the measured data points. As is apparent from the data points in Figures 8A and 8B , note that the measurements were made in increments of 0.5 cm to 2.5 cm, with measurements generally made every 1 cm, with smaller increments in the region where the polymer transition is pronounced, and larger increments once approximately 15 cm to 20 cm from the distal end are reached. Thus, the slope provides an indication of the abruptness of the change in bending stiffness over a given segment of the catheter.

Table 1: Variation in stiffness of various microcatheters across different distal segment sizes.

As shown, Plato 17 has the lowest measured slope across the distal 15 cm segment, the distal 35 cm segment, and the distal 50 cm segment. Based on the data of FIG. 8A and FIG. 8B , as further disclosed in Table 1, in some embodiments, the catheter devices described herein have a bending stiffness slope ((N·m ² )/cm) of no more than about 6.0×10 ^-7 for the distal 15 cm segment, a bending stiffness slope ((N·m ² )/cm) of no more than about 9.0×10 ^-7 for the distal 35 cm segment, and/or a bending stiffness slope ((N·m ² )/cm) of no more than about 9.0×10 ^-7 for the distal 50 cm segment. Although the Plato 17 device configured according to the present disclosure achieves each of the aforementioned features, none of the other existing catheter devices tested were able to achieve the above features.

In some embodiments, at least a portion of the distal 35 cm of the catheter device has a bending stiffness of 5×10-6 N·m ² or greater. In some embodiments, in addition to the aforementioned stiffness minimums, the catheter devices described herein have a bending stiffness slope ((N·m ² )/cm) of no more than about 4.0× ^10-6 for the distal 35 cm segment and/or a bending stiffness slope ((N·m ² )/cm) of no more than about 4.5× ^10-6 for the distal 50 cm segment. As shown in FIGS. 8A and 8B and Table 1, while the Plato 17 device met these requirements, the Headway-17 catheter did not meet the minimum bending stiffness requirement, and none of the other tested catheters met the slope requirements.

Fig. 9 compares the outer diameters of the Plato 17 device according to the present disclosure and various conventional catheter devices along the distal length. The larger data points represent points where the polymer transition is clearly visible. The data from Fig. 9 are also presented in Table 2, which shows the maximum diameter variation in the distal 15 cm section and the distal 35 cm section of each catheter device. As shown, the Plato 17 diameter does not exceed 0.0017 inch across the distal 15 cm section and the distal 35 cm section.

Table 2: Variation in diameter of various microcatheters across different distal segment sizes.

In some embodiments, the catheter devices described herein have (1) a bending stiffness of 5× ^10-6 N· ^m2 or greater in at least a portion of the distal 35 cm of the catheter device, (2) an outer diameter variation of no more than 0.002 inches across the distal 15 cm segment and/or the distal 35 cm segment, and (3) a bending stiffness slope ((N· ^m2 )/cm) of no more than about 1.3× ^10-6 for the distal 15 cm segment, a bending stiffness slope ((N· ^m2 )/cm) of no more than about 4.2× ^10-6 for the distal 35 cm segment, and/or a bending stiffness slope ((N· ^m2 )/cm) of no more than about 1.1× ^10-5 for the distal 50 cm segment. Although the Plato 17 device configured in accordance with the present disclosure achieves each of the foregoing features, none of the other existing catheter devices tested were able to achieve the above features. That is, the Headway-17 catheter did not meet the minimum bending stiffness requirement, the Echelon-10 catheter met the diameter change requirement, and none of the other tested catheters met the slope requirement.

In some embodiments, the beneficial bending stiffness distribution characteristics described above are particularly applicable to a transition section where a first polymer of the outer member transitions to a second polymer of the outer member.

In some embodiments, shaft 112 maintains substantially the same wall thickness along its length. Other catheter devices based on coils and/or braids typically have adjusted wall thickness at transition points. Variations in wall thickness can introduce additional kink points or stress points and/or require additional manufacturing steps to manage.

In some embodiments, there may be acceptable bending stiffness variations associated with the distal tip region as the shaft 112 transitions to the coil 114 and/or the coil 114 transitions to the distal-most section of the liner 110. These stiffness variations may be acceptable because they are very close to the distal end 103. Thus, in some embodiments, the distal-most 3 to 5 cm may not be within the aforementioned bending stiffness variation limits.

Catheter fatigue resistance

The catheter devices described herein also beneficially provide effective fatigue resistance. For example, in a bending and torsion fatigue test method based on ASTM E2948, the catheter devices described herein are able to achieve greater than 20 cycles before rupture. The bending and torsion fatigue test method is described in more detail in document TM-00127, which is attached hereto as Appendix 1. In short, the test is adapted from ASTM E2948, a standard test method for measuring rotational bending fatigue of solid circular fine wire.

The effective fatigue resistance of the disclosed catheter device can exist along the entire length of the shaft portion of the device, or along one or more sub-sections of the device (e.g., along one or more sections having a length of about 3 cm to 35 cm, or about 3 cm to 20 cm, or about 3 cm to 10 cm). The effective fatigue resistance is provided by one or more of the following parameters: (1) retaining the ring width less than or equal to about 30% of the corresponding outer diameter of the shaft 112; and/or (2) retaining the cutting depth greater than or equal to about 11% of the outer diameter of the shaft 112.

Example Guidewire

As described above, the catheter device of the present disclosure may be operated in conjunction with various guidewire devices to achieve the benefits described herein (e.g., advancing the catheter device over the guidewire device in a tortuous path by applying a pushing force of 50 g or less on the proximal portion of the catheter device).

Figures 10 to 20 illustrate components and aspects of example guidewires that can be used in conjunction with the catheter devices described herein. Although Figures 10 to 20 focus on guidewire devices that include manually shaped tips and/or specific incision patterns, at least in some aspects, in light of this disclosure, it will be appreciated that guidewire devices used in conjunction with the catheter devices of the present disclosure may include additional or alternative features and/or components.

Examples of guidewire features and components that may be used with the guidewires of the disclosed guidewire and catheter systems are described in U.S. Patent No. 11,369,351 (disclosing distributed, incomplete ramp and sawtooth cut patterns for guidewire tubes), U.S. Patent Application No. 2021/0228845 (describing a guidewire device in which the outer diameter of the tube is greater than the outer diameter of the proximal segment of the core and includes various coil configurations to provide centering of the distal segment of the core within the tube), and U.S. Patent Application No. 2021/0346656 (describing a guidewire device having a high ratio of torsional stiffness to lateral bending stiffness), the entire contents of each of the foregoing patent applications are incorporated herein by reference.

Figure 10 shows an example guide wire device 200 with a core 202. A tube 204 is coupled to the core 202 and extends distally from an attachment point 203 to the core 202. As shown, the distal section of the core 202 extends into the tube 204 and is surrounded by the tube 204. In some embodiments, the core 202 includes one or more tapered sections so that the core 202 can fit in the tube 204 and extend into the tube 204. For example, the distal section of the core 202 can be ground so as to taper to a smaller diameter at the distal end. In this example, the core 202 and the tube 204 have substantially similar outer diameters at the attachment point 203, where they abut and attach to each other. In some embodiments, the core 202 and the tube 204 have different outer diameters at the attachment point 203, where they abut and attach to each other, and the difference in diameter is compensated by welding, solder, adhesive, interference fit or other structural attachment methods.

Tube 204 is connected to core 202 (for example, using adhesive, soldering and/or welding) in a manner that allows torsional force to be transmitted from core 202 to tube 204 and thus further transmitted to the distal side by tube 204. Tube 204 can be connected to core wire 202 at the distal end of the device with medical grade adhesive 220, and form an anti-damage covering layer (covering). As explained in more detail below, tube 204 is micro-machined to include a plurality of incisions. The incision is arranged to form an incision pattern, which beneficially provides effective formability near the distal tip of guide wire device 200, while also maintaining good torsional properties. For clarity, incision pattern is not shown in Figures 10 and 11. Figures 12 to 14 show examples of incision patterns that can be used for tube 204.

The proximal section 210 of the guidewire device 200 extends a certain length proximally, and this length is necessary for the sufficient guidewire length provided to be delivered to the target anatomical region. The proximal section 210 generally has a length ranging from about 50cm to 350cm. The proximal section 210 can have a diameter of about 0.014 inches, or a diameter in the range of about 0.008 inches to 0.125 inches. The distal section 212 of the core 202 can taper to a diameter of about 0.002 inches, or a diameter in the range of about 0.001 inches to 0.050 inches. In certain embodiments, the tube 204 has a length in the range of about 3cm to 100cm.

In some embodiments, the distal section 212 of the core 202 tapers to a circular cross section. In other embodiments, the distal section 212 of the core 202 has a flat or rectangular cross section. The distal section 212 may also have another cross-sectional shape, such as another polygonal, oval, irregular shape, or a combination of different cross-sectional shapes at different regions along its length.

Typically, the user will shape the distal end of the guidewire device 200 by manually bending, twisting or otherwise manipulating the distal (approximately) 1 cm to 3 cm of the guidewire device 200 into a desired shape. This length is schematically shown as a distal "tip" 206 in FIG. 10. In some embodiments, the tip 206 includes one or more formable components (inside the tube 204) formed of stainless steel, platinum and/or other formable materials. In a preferred embodiment, the tip 206 includes one or more components formed of a material exhibiting work hardening characteristics, so that the tip provides a higher elastic modulus at the formed section than before forming when forming (i.e., plastic deformation).

FIG. 11 shows a cross-sectional view of the guidewire device 200 of FIG. 10 . As shown, the core 202 includes a proximal section 210 and a distal section 212, and the distal section has a smaller diameter than the proximal section 210. A coil 214 is located on at least a portion of the distal section 212 of the core 202. The coil 214 is preferably formed by one or more radiopaque materials (such as platinum, gold, silver, palladium, iridium, osmium, tantalum, tungsten, bismuth, dysprosium, gadolinium, etc.). Additionally or alternatively, the coil 214 can be at least partially formed by stainless steel or other materials that can effectively maintain shape after being bent or otherwise manipulated by a user. In the illustrated embodiment, the coil 214 is arranged at or near the distal end of the device and extends a distance proximally toward the attachment point 203. In some embodiments, the coil 214 has a length substantially consistent with the length of the tube 204. In other embodiments, the coil 214 is shorter. For example, coil 214 may extend 1, 2, 4, 6, 8, 10, 12, 15, 20, 25, 30, or 35 cm from the distal end, or may extend from the proximal end a distance within a range defined by any two of the foregoing values.

In some embodiments, the coil 214 is formed as a unitary piece. In other embodiments, the coil 214 includes a plurality of separate segments positioned adjacent to each other and/or interlocked by interwoven coils. Such separate segments may additionally or alternatively be brazed, adhered to, or otherwise fastened to each other to form a complete coil 214. Some embodiments may include two or more coils, wherein at least one of the coils is configured to provide non-radioactive properties, and at least one of the coils is configured to improve the centering of the distal segment 212 of the core 202 within the tube 204 in size and shape.

Although the illustrated embodiment shows a space between the coil 214 and the tube 204, it should be understood that this is schematically done for ease of viewing. In some embodiments, the size of the coil 214 is configured to fill and pack a larger proportion of the space between the distal section 212 and the tube 204. For example, the size of the coil 214 can be configured to be close to the distal section 212 of the core 202 and also close to the inner surface of the tube 204. Other embodiments include space between the core 202 and the tube 204 for at least a portion of the section of the guidewire device 200 that the tube 204 and the core 202 extend together.

The coil 214 can be advantageously used to pack the space between the core 202 and the tube 204 so as to align the curvature of the distal section 212 of the core 202 with the curvature of the tube 204. For example, when a curvature is formed in the tube 204, the tightly packed section of the coil 214 acts as a packing between the tube 204 and the distal section 212, imparting the same curvature to the distal section 212. In contrast, a guidewire device that omits the coil does not follow the same curve as the tube when it is bent at the tube, but instead extends until it abuts against the inner surface of the tube and is then forced to bend.

Embodiments described herein advantageously allow distal tip 206 to be shaped to the desired position, and keep a sufficiently long period of time in the shaped position.Compared with traditional guide wire devices, the illustrated embodiments can form and keep a shaped structure.For traditional guide wire devices, due to the performance mismatch between tube structure and internal components (core and coil), problems related to formability often occur.Tube structure is usually formed by nitinol or other superelastic materials.This pipe will deviate to its original (straight) position when being bent or shaped, thereby applying restoring force to any formable internal components, causing the loss of the customized shape of deformation and tip.

Usually, for example, conventional guide wire will have a shaped tip before deployment, but in the use of guide wire, as the superelastic tube flexes toward the initial shape opposite to the desired tip shape, the shaped tip will lose or degenerate. Therefore, the restoring force applied by the tube acts on (acts against, resistively acts on) the internal components to reduce or degenerate the desired shape set by the user. On the contrary, embodiments described herein include such features: tip 206 can be shaped when it will not be subject to the dominant (overriding) restoring force from tube. As described below, pipe 204 can include an incision pattern that keeps effective torsional property, while also providing enough flexibility at distal tip 206, to avoid disturbing the customized shape of tip 206.

Figures 12 to 16 show exemplary embodiments of tube cut patterns that may be used in one or more of the guidewire device embodiments described herein. For example, the tube 204 of the embodiment shown in Figures 10 and 11 may be cut according to one or more of the structures shown in Figures 12 to 16.

FIG. 12 shows a tube 504 having a series of cuts 508 that form (axially extending) beams 530 and rings 540 (extending transversely and circumferentially). In the illustrated embodiment, the cuts 508 are arranged on the tube as a series of "bypass cuts". As used herein, a bypass cut is a cut that has no opposing cut directly opposite it relative to the longitudinal axis of the tube, thereby leaving a single beam 530 of longitudinally extending material between the rings 540 of transversely and circumferentially extending material. The "bypass" cut pattern may also be referred to herein as a "single beam" cut pattern. The cross-sectional geometry of the beam can be a variety of shapes, including semi-circular (such as a shape made by a dicing saw with a circular blade), flat sided (such as a shape made by a laser machining operation), or any type of cross-sectional shape. In the illustrated embodiment, the cuts are arranged as alternating cuts offset by approximately 180 degrees from one cut to the next along the length of the tube 504, but may also be made rotationally offset at angles other than 180 degrees to 0 degrees as described below.

As shown in the figure, the pipe formed by cutting one or more sections of bypass (i.e. single beam) can provide many benefits, particularly provides many benefits about the associated shaped tip of guide wire device.For example, the flexibility of the pipe with bypass otch is relatively greater than the flexibility (for example, assuming that beam width, ring size and otch spacing are equal in other aspects) of the pipe of multiple beams left between continuous rings without otch or the otch with.Advantageously, the flexibility of the increase provided by bypass otch arrangement reduces to greatest extent or prevents that pipe makes the shape deformation of the internal structure of guide wire.For example, the core (for example stainless steel) arranged in pipe can be bent or flexed (i.e. plastic deformation), so that the tip of guide wire provides the shape of expectation.

As described above, in many cases, the forces associated with the elastic recovery of the tube will be exerted on the shaped core and tend to straighten the shaped core (at least relative to the portion of the shaped core that is disposed within the tube). Therefore, appropriately adjusting the flexibility of the tube will reduce the restoring forces exerted on the shaped core and allow the shaped core to better maintain its shape.

In some embodiments, the depth of a continuous bypass incision or a group of bypass incisions gradually increases as each continuous incision or group of incisions moves toward the distal end. Thus, a tube with desired flexibility and torquability can be configured for a given application using a profile of incision depths. For example, a tube configuration can include a proximal section with relatively low flexibility and relatively high torquability that rapidly progresses to a distal section with relatively high flexibility and relatively low torquability as the bypass incisions rapidly deepen toward the distal end. In some embodiments, a section with relatively deep incisions is formed only at the most distal section of the tube where formability is expected or desired (e.g., 1 cm to 3 cm distal to the tube) so as to retain higher torquability for the remainder of the tube.

Bypass incision 508 can change according to depth, width and/or spacing.For example, as incision 508 is closer to the distal tip of device, incision can become deeper and deeper and/or interval is more and more closely.Deeper and/or tighter incision provides relatively greater flexibility.Therefore, a gradient can be formed, which provides more and more guide wire flexibility in the area of the guide wire gradually more distal.As described in more detail below, bypass incision 508 can also be arranged with alternating angular positions according to the angular offset applied at each adjacent incision or applied at the adjacent incision group.The illustrated embodiment shows the angular offset of 180 degrees from one incision to the next incision.Some embodiments can include the angular offset of about 5 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, 80 degrees or 85 degrees from one incision to the next incision or from one group of incisions to the next group of incisions.

FIG13 shows another embodiment of a tube 604 having a bypass cut and a set of opposing, deeply offset dual beam cuts disposed proximal to the bypass cut. In the illustrated embodiment, a set of bypass cuts creates beams 630. Proximal to beams 630 is a set of cuts arranged as opposing cuts that create beams 634. Although not visible in this view, an additional beam is formed opposite each beam 634 (obstructed behind beam 634 in this view). Thus, each ring 640 in the deeply offset dual beam cut pattern has a set of two beams connecting the ring to its proximal neighboring ring, and a set of two beams connecting the ring to its distal neighboring ring.

As shown, the opposing dual beam cuts are offset in depth so that for each opposing pair of cuts (one cut on each side of the tube axis), the depth of one cut is greater than the depth of the opposing cut. Such depth-offset dual beam cuts can be advantageously used to transition from a section of bypass cuts (as shown in FIG. 12 ) to a section of non-offset opposing dual beam cuts (as shown in FIG. 14 ).

14 shows a section of a tube 250 having a dual beam cut pattern, with each cut of each opposing cut pair having approximately the same cut depth so that the resulting beams are substantially equally spaced circumferentially. As shown, the cuts result in a pair of beams 234 between each ring 240. The cuts shown here are angularly offset by approximately 90 degrees from one pair of opposing cuts to the next pair of cuts, but other angular offsets may also be used.

A section of the tube having a dual beam cut pattern with beams substantially equidistantly spaced circumferentially generally has a relatively high ability to transmit torque and a relatively low flexibility, whereas a section of the tube having a bypass cut generally has a relatively low ability to transmit torque and a relatively high flexibility. The torque transmittance and flexibility of a section of the tube having a deep offset dual beam cut configuration generally lies between that of a section of deeply symmetrical opposing dual beam cuts and that of a bypass cut. The greater the difference between the depths of the opposing cuts, the closer the resulting beams are in the circumferential direction, and thus the more similar the offset dual beam cut is to a single beam/bypass cut. Likewise, the more similar the depths of the opposing cuts, the more similar the offset dual beam cut is to a symmetrical dual beam cut.

Embodiments of the tube including an offset dual beam section advantageously provide a transition zone that can be positioned and configured to provide desired transition characteristics between the distal bypass cutout region and the proximal symmetrical dual beam section. For example, the transition zone can be relatively gradual or abrupt, depending on the length of the transition zone and/or on the rapidity of the change in offset in successive cutouts. Thus, the tube can be configured to provide a proximal section with greater torquability and less flexibility that transitions to a more flexible distal section with greater flexibility to better maintain a bent shape when formed by an operator. The position and configuration of the proximal section, transition section, and distal section are adjustable to optimize the benefits of effective torquability and formable tip performance.

15 shows another embodiment of a tube 704 having a single beam cutout that forms a plurality of beams 730 and rings 740. As shown, the cutouts are arranged so that the beams 730 are aligned along one side of the tube 704, rather than being alternately positioned at 180 degrees or some other angular amount. Such an embodiment can advantageously provide preferential bending in one direction (e.g., toward the aligned beams 730), further minimizing the associated restoring forces away from the axis of the tube.

Figure 16 shows an embodiment of pipe 304, and this pipe 304 has the angle offset between bypass incision pattern and incision group.As shown in the figure, angle offset makes the beam 330 obtained along the length of pipe section with rotation/spiral circumferential pattern positioning.In certain embodiments, the first angle offset is applied to the next incision from an incision in a group of incisions, and the second angle offset is applied to the next group of incisions from a group of incisions.For example, as shown in Figure 16, each incision 308 in a pair of adjacent incisions can offset about 180 degrees, thereby being located on the opposite sides relative to the longitudinal axis of guide wire and leaving the formed beam 330, while every pair (incision) and adjacent pair (incision) offset some other angle offsets (for example, offset about 5 degrees in the illustrated embodiment).In this way, the angle offset of setting (intra-set) in the group can position beam 330 on the opposite side of the guide wire axis, and the angle offset of setting (inter-set) between the groups can adjust the angular position of the continuous beam to be enough to minimize the preferred bending direction of guide wire on a section of several groups of incisions 308.

Rotational offsets may also be applied to the cut patterns shown in Figures 12 to 15. In preferred embodiments, each successive cut or group of cuts (e.g., every second cut, every third cut, every fourth cut, etc.) along the length of a given segment is rotationally offset by about 1, 2, 3, 5, or 10 degrees, or about 1, 2, 3, 5, or 10 degrees from 90 degrees in a dual beam configuration, or about 1, 2, 3, 5, or 10 degrees from 180 degrees in a single beam configuration. These rotational offset values have advantageously shown good ability to eliminate buckling deviations.

For example, in the double beam incision pattern, as shown in Figure 14, every pair of beams is equally spaced circumferentially, and the rotational offset of about 1 degree, 2 degree, 3 degree, 5 degree or 10 degree from 90 degrees will position every other pair of beams to have several degrees of misalignment (misalignment) along the length of the incision section. For example, the second pair of beams can be slightly greater than or less than 90 degrees from the first pair of beams rotational offset, but the third pair of beams will only be from the first pair of beams rotational offset several degrees, and the fourth pair of beams will only be from the second pair of beams rotational offset several degrees. When the length of the incision section of the guide wire device is arranged in this way, the resulting structure allows the incision pattern to enhance flexibility, without introducing or aggravating any direction (directional) flexibility deviation.

The individual components and features of the tube embodiments shown in Figures 12-16 can be combined to form different tube configurations. For example, some tubes can be configured with a segment having a bypass (single beam) cutout (as shown in Figures 12, 15, and/or 16) and a segment having a symmetrically spaced dual beam cutout (as shown in Figure 14), optionally with one or more depth offset dual beam cutouts (as shown in Figure 13). For example, some tube embodiments can include a proximal segment having a symmetrically spaced dual beam cutout pattern that transitions to a distal segment having a bypass cutout arrangement.

The embodiments described herein can advantageously enable a more proximal region of the tube to transmit relatively greater torque while reducing the torquability of a more distal section of the tube to allow tip shaping without excessively sacrificing torquability. Thus, the features of the guidewire device can be adjusted to a specific need or application to optimize the operational relationship between torquability, flexibility, and tip formability.

In a preferred embodiment, the formable distal section of the core has a certain stiffness that can withstand the expected bending forces acting on the distal section of the core from the tube after the distal section of the core is formed. In some embodiments, the formable distal section of the core is formed of a material or a combination of materials that provides an elastic modulus greater than about 1.5 to 4 times, or about 2 to 3 times, the elastic modulus of the material (one or more) used to form the tube.

FIG. 17 shows an embodiment of a tube 804 having a first segment 850, a second segment 860, and a third segment 870. The second segment 860 is located distally of the first segment 850, and the third segment 870 is located distally of the second segment 860. Each of the segments 850, 860, and 870 can be distinguished from each other by the cut pattern of each segment. As described above with reference to other embodiments described herein, the cut pattern can produce rings 840 and beams 803 within the tube. The segments 850, 860, and 870 shown in FIG. 17 can have different cut patterns in each segment. For example, the first segment 850 can have a double beam cut pattern, the second segment 860 can have a single beam cut pattern, and the third segment 870 can have a double beam cut pattern.

It will be appreciated that other embodiments may include different cutout patterns than those shown in FIG. 17. For example, in one embodiment, the first segment 850 may have a cutout pattern with more than two beams, the second segment 860 may have a double beam cutout pattern or a single beam cutout pattern, and the third segment 870 may have a single beam cutout pattern or may be omitted. In addition, other embodiments of the tube 804 may include more or less than three segments along its length. For example, an embodiment of the tube 804 may include four or more segments. In addition, for example, an embodiment of the tube 804 may include only one or two segments. The cutout patterns shown in any other embodiment described herein may be used.

FIG. 18A shows a side view of an embodiment of a tube 904 similar to the embodiment of the tube shown in FIG. 17 . The tube of FIG. 18A also shows a partial cross-sectional view of a second section 960 to show the distal section 912 of the core 902 extending through the tube 904 and the coil 914. Although only a partial cross-section is shown here, it should be understood that the core 902 will generally extend all the way to the distal end 922 of the device. In the illustrated embodiment, the second section 960 of the tube 904 includes a single beam cutout pattern. The single beam cutout pattern creates a series of axially extending beams 930, each beam being disposed between a pair of adjacent circumferentially extending rings 940.

In the illustrated embodiment, the consecutive beams 930 alternate in position (i.e., each consecutive beam 930 has a rotational offset of approximately 180°) from the first side 916 of the tube 904 to the second side 918 of the tube 904. In another embodiment, the beams 903 of the single beam cutout pattern of the second segment 960 can all be positioned along the same side of the tube to form a backbone of aligned beams 930 extending axially along the tube 904 and connecting the plurality of rings 940, similar to the embodiment shown in FIG. 15.

As shown in FIG18A , the single beam cut pattern of the second section 960 creates a preferred bending plane B. As shown in FIG18A , the preferred bending plane B extends axially along and transversely through the tube 904. Because the beams 930 of the second section 960 extend axially with the tube 904, the tube 904 is most flexible along the preferred bending plane B. That is, the beams 930 are configured such that the tube 904 has the least resistance to bending along the preferred bending plane B as compared to any other plane. In this example embodiment, the cut pattern of the second section 960 creates the preferred bending plane B, whether creating an alternating pattern of beams 930 as shown in FIG18A or a single trunk of beams 930 as described above.

In addition, as shown in FIG. 18A , the distal section 912 of the core 902 tapers as the core extends distally through the coil 914 and the tube 904, and tapers to a flat ribbon-like configuration at the distal portion. FIG. 18B shows a cross-sectional view of the tube 904 through the plane A-A of FIG. 18A . The distal section 912 of the core 902 is a substantially flat ribbon extending axially within at least the second section 960 of the tube 904. The ribbon-like configuration of the core 912 has a major dimension D1 and a minor dimension D2. The major dimension D1 of the distal section 912 of the core 902 is greater than the minor dimension D2 of the core 912, so that the major plane of the ribbon-like distal section 912 of the core 902 extends orthogonal to (and preferably perpendicular to) the preferred bending plane B. In this way, the bending resistance of the distal section 912 of the core 902 and the tube 904 in the preferred bending plane B is also minimal. In other words, the core 912 can be gradually tapered into a ribbon-like configuration and extend axially along the tube 904 so that the distal section 912 of the core 902 is aligned with the beams 930 of the second section 960, thereby sharing the preferred bending plane B with the tube 904.

In one embodiment, the length of the second section 960 of the tube 904 is about 0.5 cm to about 5 cm. In another embodiment, the length of the second section 960 of the tube 904 is about 1 cm to about 2 cm. In yet another embodiment, the length of the second section 960 of the tube 904 is about 1 cm to about 1.5 cm. The distance to which the second section 960 extends from the distal end 922 can vary according to the length of the tube 904 that is bent or shaped for a given surgery. If necessary, these distances can vary between embodiments to accommodate various surgeries. Other features of the embodiments shown in Figures 17 to 18B, including the materials and dimensions of the coil 914, tube 904, and core 902, as well as specific features related to the incision pattern, can be similar to other embodiments described herein with reference to other figures.

FIG. 19 shows a close-up view of the transition between a first section 950 and a second section 960 of a tube 904. In the illustrated embodiment, the first section 950 includes a dual beam cut pattern and the second section 960 includes a single beam cut pattern. The stiffness of the tube 904 in each section depends at least in part on the amount of material remaining in the tube 904 after the cuts are made and the amount of material remaining in the arrangement/spacing of the remaining beams 930. For example, all other things being equal, a section of the tube 904 having two beams 930 between each pair of adjacent rings 940 will have a greater stiffness than a section of the tube 904 having a single beam 930 of the same size between each pair of adjacent rings 940. Also, for example, all other things being equal, a section of the tube 904 having a greater distance between the cuts will have a greater stiffness than a section having a smaller distance between the cuts. That is, the greater the distance between the cuts, the greater the thickness of the ring 940 formed between the cuts, and the greater the stiffness of the tube 904 in that section.

The cutouts, rings 940, and beams 930 disposed at or near the transition point between the first section 950 and the second section 960 of the tube 904 shown in FIG19 are configured so that the stiffness distribution of the tube 904 is approximately continuous over the transition between the two sections 950 and 960. In other words, the cutout patterns of the first section 950 and the second section 960 are arranged to avoid a significant jump in stiffness, either up or down, from one side of the transition point to the other.

Of course, depending on the particular granularity level at which the stiffness is measured along the tube 904 and on the specified length of the measured segment, there may be some degree of discrete variation in stiffness between different measured segments. Because an infinite number of stiffness measurements cannot be made, the actual measurable stiffness distribution will consist of stiffness levels measured at each of a series of discrete segment lengths of the tube. Although the jump (i.e., change in stiffness) from one measured segment to the next measured segment may be discrete, the overall pattern of such jumps preferably approximates a linear series or at least a smooth curve. Therefore, in the context of the present disclosure, a "significant jump" occurs when the jump from one segment to the next is greater than any immediately adjacent jump by more than about 1.5 times. Therefore, when there is no jump greater than more than about 1.5 times any adjacent jump at a transition point, significant jumps are avoided, and the stiffness distribution at the transition point is therefore "continuous". Preferably, there is no jump greater than more than about 1.2 times any adjacent jump at a transition point.

FIG. 19 shows an embodiment of a tube 904 having rings 940 and beams 930 that achieve a continuous stiffness distribution at the transition between segments 950, 960. In the embodiment shown, the axial thickness of the most proximal ring 940a of the second segment 960 is greater than the axial thickness of the most distal ring 940b of the first segment 950. In this way, the total amount of material of the tube 904 at the transition is similar between the segments 950, 960 at or near the transition. As described above, this results in continuous stiffness across the transition. In addition, the axial thickness of the ring 940 of the second segment 960 can decrease distally along the length of the tube 904, so that the stiffness decreases accordingly. This is shown in FIG. 19, but more clearly shown in FIG. 18A.

Turning now to FIG. 20 , a distal tip 906 of the tube 904 is shown. The distal tip 906 shown in FIG. 20 includes a third segment 970, at least a portion of the second segment 960, and a polymer adhesive 920 disposed distally of the third segment 970 at the distal end 922 of the tube 904. The third segment 970 of the tube 904 includes a double beam cut pattern that forms two beams 930 between each pair of adjacent rings 940. This is in contrast to the single beam cut pattern of the second segment 960. It should be understood that the transition between the second segment 960 and the third segment 970 can be similar to the transition between the first segment 950 and the second segment 960 as described above. That is, the stiffness of the tube 904 can be approximately continuous over the transition from the second segment 960 to the third segment 970.

The adhesive 920 disposed at the distal end 922 of the tube 904 can extend between the tube 904 and the core at the distal end 922 of the tube 904 to secure the tube 904 and the core together. As shown in FIG. 10 , the distal section 212 of the core 202 can extend distally beyond the tube 204 and into the adhesive 220. The adhesive 220 can thus be used to couple the tube 204 to the core and/or the coil 214.

Referring again to FIG. 20 , adhesive 920 may be disposed on the distal end 922 of the tube 904 and at least partially wicked proximally and into one or more of the cutouts between the respective rings 940 and beams 930 of the third section 970. The double beam cutout pattern of the third section 970 provides an increased surface area of the tube 904 material to which the adhesive 920 can be bonded compared to the single beam cutout pattern of the second section 960. Thus, the double beam cutout pattern of the third section 970 provides a stronger connection between the adhesive 920 and the distal section of the core and/or coil. It should be understood that a cutout pattern including more than two beams 930 between each pair of adjacent rings 940 may therefore be used to enhance the connection strength between the tube 904 and the distal section of the core 202 and/or coil. However, as described above, the more material the cutout removes from the tube 904, the less stiff the tube 904 will be, and vice versa.

Furthermore, during manufacturing, placing a greater amount of adhesive 920 on the distal end 922 of the tube 904 will cause the adhesive 920 to wick proximally further up the tube 904. Due to the number and spacing of the cuts in the cut pattern, the double beam cut pattern of the third section 970 provides an effective visual indication for the manufacturer to see how far the adhesive 920 is wicking proximally to the third section 970. This visual indication of the third section 970 can also help a machine or other automated manufacturing device detect how far the adhesive 220 is wicking proximally on the third section 970 during manufacturing.

For example, when the manufacturer places adhesive 920 on the distal end 922 of the tube 904 during manufacturing, the adhesive may begin to wick through the space between the loops 940 and beams 930 in the third section 970. Because the double beam cut pattern of the third section 970 provides a visual indication, the manufacturer can more easily discern how far the adhesive wicks proximally along the tube 904 from one loop 940 to the next compared to the single beam cut pattern of the second section 960. The manufacturer can therefore determine how much adhesive 220 to place on the distal end 922 of the tube 904. The manufacturer can also determine when to stop adding adhesive 220 based on a predetermined distance or predetermined loop 940 to which the adhesive 920 is wicked.

In one embodiment, the third section 970 of the tube 904 extends from the distal end 922 of the tube 904 by about 0.5 mm to 1.5 mm. In another embodiment, the third section 970 of the tube 904 extends from the distal end 922 of the tube 904 by about 0.75 mm to 1.25 mm. In yet another embodiment, the third section 970 of the tube 904 extends from the distal end 922 of the tube 904 by about 1 mm. Depending on the length of the tube 904 that needs to be bent or shaped or the distance required for the adhesive 920 to be fully wicked along the tube 904, the distance to which the third section 970 extends from the distal end 922 can vary. As needed, these distances can vary between different embodiments to accommodate various tubes and surgeries. Other features of the embodiments shown in Figures 19 and 20, including the materials, properties and dimensions of the coil 914, the tube 904 and the core 902, can be similar to other embodiments described herein with reference to other figures.

Additional Terms and Definitions

While certain embodiments of the present disclosure have been described in detail with reference to specific configurations, parameters, components, elements, etc., these descriptions are illustrative and should not be construed as limiting the scope of the claimed invention.

As used herein, the term "microfabrication" refers to any manufacturing process capable of manipulating raw materials to form a catheter device having one or more features disclosed herein, including any manufacturing process capable of forming a gap in the inner shaft disclosed herein. Examples include, but are not limited to, laser cutting and blade cutting.

For any given element or component of the described embodiments, unless otherwise stated or implied, any possible alternatives for that element or component may generally be used alone or in combination with each other.

Unless otherwise indicated, numbers used in the specification and claims to indicate quantities, components, distances, or other measurements should be understood as being optionally modified by the term "about" or its synonyms. When the terms "about," "approximately," "substantially," and the like are used in conjunction with a stated amount, value, or condition, they may be considered to refer to an amount, value, or condition that deviates from the stated amount, value, or condition by less than 20%, less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01%. At a minimum, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Any headings and sub-headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims.

It will also be noted that, as used in this specification and the appended claims, the singular forms "a", "an", and "the" do not exclude plural referents unless the context clearly dictates otherwise. Thus, for example, an embodiment referring to a singular referent (e.g., "a widget") may also include two or more such referents.

It will also be understood that the embodiments described herein may include properties, features (e.g., components, members, elements, parts, and/or portions) described in other embodiments described herein. Therefore, the various features of a given embodiment may be combined with and/or incorporated into other embodiments of the present disclosure. Therefore, the disclosure of certain features relative to a specific embodiment of the present disclosure should not be interpreted as limiting the application or inclusion of the features to the specific embodiment. On the contrary, it will be understood that other embodiments may also include such features.

Claims (20)

1. An intravascular system comprising:

a catheter device configured for guiding through a blood vessel comprising one or more folds having a radius of curvature of 10mm or less than 10mm, wherein for at least a portion of the blood vessel the ratio of the inner diameter of the blood vessel to the outer diameter of the catheter device is about 300% to about 800%; and

A guidewire device configured for guiding through the blood vessel,

Wherein the catheter device and guidewire device are configured such that the catheter device advances over the guidewire device in response to a pushing force of 50g or less applied to the catheter device.

2. The intravascular system of claim 1, wherein the vessel has a path length of at least 10cm.

3. The intravascular system of claim 1, wherein the vessel has a path length of at least 20cm.

4. The intravascular system of claim 1, wherein the one or more flexures comprise 3 or more flexures.

5. The intravascular system of claim 1, wherein each of the one or more flexures has a radius in a range of about 4mm to about 9 mm.

6. The intravascular system of claim 1, wherein the catheter device is configured to advance over the guidewire device in response to a pushing force of 40g or less applied to the catheter device.

7. The intravascular system of claim 6, wherein the catheter device is configured to advance over the guidewire device in response to a pushing force of 30g or less applied to the catheter device.

8. The intravascular system of claim 7, wherein the catheter device is configured to advance over the guidewire device in response to a pushing force of 20g or less applied to the catheter device.

9. The intravascular system of claim 1, wherein a ratio of an inner diameter of the vessel to an outer diameter of the catheter device is at least about 371%.

10. The intravascular system of claim 1, wherein the catheter device comprises:

A microfabricated inner shaft having a plurality of gaps formed therein; and

An outer member comprising a polymeric material disposed within the gap.

11. The intravascular system of claim 10, wherein the inner shaft comprises a plurality of axially extending beams that couple a plurality of circumferentially extending rings.

12. The intravascular system of claim 11, wherein the inner shaft comprises one or both of a tri-beam section and a dual-beam section, wherein the tri-beam section is disposed proximal to the dual-beam section, and wherein at least a portion of the tri-beam section has a higher bending stiffness than the dual-beam section.

13. The intravascular system of claim 10, wherein the outer member comprises a plurality of different polymer durometer.

14. The intravascular system of claim 13, wherein the outer member comprises a transition section in which a first polymer is adjacent to a second polymer of a different stiffness, the transition section comprising a change in bending stiffness of the outer member, and wherein the microfabricated shaft comprises a section consistent with the transition section configured to compensate for the change in bending stiffness of the outer member such that an overall change in bending stiffness of the catheter device at the transition section is less than an overall change in bending stiffness of the outer member itself at the transition section.

15. The intravascular system of claim 14, wherein the second polymer is proximal to the first polymer and has a greater stiffness than the first polymer such that the bending stiffness of the outer member increases across the transition section in a distal-to-proximal direction, and wherein the bending stiffness of the shaft does not increase across at least a portion of the transition section in the distal-to-proximal direction to compensate for the increase in bending stiffness of the outer member.

16. The intravascular system of claim 10, further comprising an inner liner about which the shaft is positioned.

17. The intravascular system of claim 16, wherein the polymeric material of the outer member is fused to the liner, fills the gap of the shaft, and covers an outer surface of the shaft to encapsulate and embed the shaft.

18. The intravascular system of claim 10, wherein the shaft is formed of nitinol.

19. The intravascular system of claim 10, wherein the catheter device has a bending stiffness slope ((N-m ²)/cm) of no more than about 6.0 x 10 ^-7 for a distal 15cm section, a bending stiffness slope ((N-m ²)/cm) of no more than about 9.0 x 10 ^-7 for a distal 35cm section, and/or a bending stiffness slope ((N-m ²)/cm) of no more than about 9.0 x 10 ^-7 for a distal 50cm section.

20. The intravascular system of claim 1, wherein the guidewire device comprises:

a core having a proximal section and a distal section; and

A tube structure coupled to the core such that a distal section of the core enters the tube structure, the tube structure having a first section and a second section distal to the first section,

Wherein the tube structure comprises a pattern of cuts forming a plurality of axially extending beams coupling a plurality of circumferentially extending rings.