Patent Publication Number: US-2021178128-A1

Title: Guidewire devices having distally extending coils and shapeable tips

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/611,328, filed Jun. 1, 2017 and titled “GUIDEWIRE DEVICES HAVING DISTALLY EXTENDING COILS AND SHAPEABLE TIPS”, which claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/363,760, filed Jul. 18, 2016 and titled “GUIDEWIRE DEVICES HAVING SHAPEABLE TIPS”. The disclosures of each of the foregoing are incorporated herein by this reference. 
    
    
     BACKGROUND 
     Guidewire devices are often used to lead or guide catheters or other interventional devices to a targeted anatomical location within a patient&#39;s body. Typically, guidewires are passed into and through a patient&#39;s vasculature in order to reach the target location, which may be at or near the patient&#39;s heart or neurovascular tissue, for example. Radiographic imaging is typically utilized to assist in navigating a guidewire to the targeted location. In many instances, a guidewire is left in place within the body during the interventional procedure where it can be used to guide multiple catheters or other interventional devices to the targeted anatomical location. 
     Some guidewire devices are constructed with a curved or bent tip to enable an operator to better navigate a patient&#39;s vasculature. With such guidewires, an operator can apply a torque to the proximal end of the guidewire or attached proximal handle in order to orient and point the tip in a desired direction. The operator may then direct the guidewire further within the patient&#39;s vasculature in the desired direction. 
     Tuning the flexibility of a guidewire device, particularly the distal sections of the guidewire device, is also a concern. In many circumstances, relatively high levels of flexibility are desirable in order to provide sufficient bendability of the guidewire to enable the guidewire to be angled through the tortuous bends and curves of a vasculature passageway to arrive at the targeted area. For example, directing a guidewire to portions of the neurovasculature requires passage of the guidewire through curved passages such as the carotid siphon and other tortuous paths. 
     Another concern related to guidewire devices is the ability of a given guidewire device to transmit torque from the proximal end to the distal end (i.e., the “torquability” of the guidewire device). As more of a guidewire is passed into and through a vasculature passageway, the amount of frictional surface contact between the guidewire and the vasculature increases, hindering easy movement of the guidewire through the vasculature passage. A guidewire with good torquability enables torqueing forces at the proximal end to be transmitted through the guidewire to the distal end so that the guidewire can rotate and overcome the frictional forces. 
     Some guidewire devices include a distally placed micro-machined hypotube positioned over the distal end of the guidewire core in order to direct applied torsional forces further distally toward the end of the device. Because torsional forces are primarily transmitted through the outer sections of a cross-section of a member, the tube is configured to provide a path for increased transmission of torque as compared to the amount of torque transmitted by a guidewire core not sheathed by a tube. 
     While such guidewire devices have provided many benefits, several limitations remain. For example, many of the design characteristics of a guidewire having a torque-transmitting tube, although functioning to provide increased torque transmission, work against and limit the shapeability of the guidewire tip. 
     BRIEF SUMMARY 
     The present disclosure relates to guidewire devices having shapeable tips and effective torquability. In one embodiment, a guidewire device includes a core with a proximal section and a distal section. The distal section may taper to a smaller diameter than at the proximal section. A tube structure is coupled to the core such that the distal section of the core passes into the tube structure and passes distally beyond the tube structure to form a shapeable tip. The guidewire device also includes an inner coil that encompasses at least a portion of the distal portion of the core. The inner coil is positioned such that a proximal portion of the inner coil is disposed between an outer surface of the core and an inner surface of the tube structure, and such that a distal portion of the inner coil extends distally beyond the tube structure to encompass at least a portion of the shapeable tip. The guidewire device also includes an outer coil coupled to a distal end of the tube structure and extending distally from the tube structure. The outer coil is positioned to encompass at least a portion of the inner coil. The tip is configured to reduce the tendency of resilient forces from the tube structure to disrupt a customized shape of the tip. 
     In one embodiment, the core is formed from and/or includes stainless steel, the tube structure is formed from and/or includes a superelastic material such as nitinol, the inner coil is formed from and/or includes a radiopaque material such as platinum, and the outer coil is formed from and/or includes stainless steel. 
     In some embodiments, the tube structure includes a plurality of fenestrations that define a plurality of axially extending beams coupling a plurality of circumferentially extending rings. The tube structure may include one or more of a one-beam, two-beam, three-beam cut pattern, or cut pattern of more than three beams. In some embodiments, a rotational offset is applied between successive segments to minimize preferred bending directions along a length of the tube structure. 
     Additional features and advantages will be set forth in part in the description that follows, and in part will be obvious from the description, or may be learned by practice of the embodiments disclosed herein. The objects and advantages of the embodiments disclosed herein will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing brief summary and the following detailed description are exemplary and explanatory only and are not restrictive of the embodiments disclosed herein or as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates an exemplary embodiment of a guidewire device providing effective torquability and having a shapeable tip; 
         FIG. 2  is a cross-sectional view of the guidewire device of  FIG. 1 ; 
         FIGS. 3 through 8  illustrate various exemplary cut patterns that may be formed in the tube of the guidewire device; and 
         FIGS. 9 through 11  illustrate various distal tip configurations that may be utilized with the guidewire device. 
     
    
    
     DETAILED DESCRIPTION 
     Introduction 
     The present disclosure relates to guidewire devices providing effective anatomical navigation capabilities. The ability to steer and direct a guidewire to a targeted anatomical location depends on balancing and optimizing tradeoffs between torquability and the ability to maintain a shaped tip. A guidewire device may include a shapeable tip to allow an operator to point the tip in a desired direction within the vasculature by rotating the distal tip. However, if the torquability of such a guidewire device is insufficient, the operator will be unable to transmit torsional forces all the way to the shaped distal tip to control the orientation of the shaped distal tip. This hindrance will become increasingly problematic as the guidewire device is advanced farther into the vasculature and experiences increasing frictional resistance. In addition, if a guidewire device is unable to properly form and maintain a shaped tip, it will have limited ability to adjust tip orientation, making intravascular navigation more difficult. 
     Embodiments described herein provide one or more features that balance and/or optimize the relationship between guidewire torquability and the ability to form and maintain a shaped tip. Such guidewires are responsive to operator manipulation during guidewire deployment, and provide effective navigation capabilities by enabling a shaped distal tip to receive transmitted torsional forces. 
     In some embodiments, the shapeable tip allows an operator to custom shape the tip, such as by manually shaping the tip just prior to deploying the guidewire device within the patient&#39;s vasculature. The operator is thus enabled to customize the shaping of the distal tip according to preferences and/or conditions particular to a given application. The guidewire device is also configured to effectively transmit torque while maintaining the shaped tip. At least some embodiments described herein include tips that are able to maintain a bent or curved shape throughout a procedure, or throughout multiple procedures, or even indefinitely until subjected to a counteracting reshaping force. 
     Guidewire Devices with Shapeable Tips 
       FIGS. 1 and 2  illustrate an exemplary guidewire device  100  having an effective shapeable tip.  FIG. 1  illustrates a side view of the device and  FIG. 2  illustrates a cross-sectional view of the device. The guidewire device  100  includes a core  102 . A tube  104  is coupled to the core  102  and extends distally from a point of attachment to the core  102 . As shown, a distal section of the core  102  extends into the tube  104  and is surrounded by the tube  104 . In some embodiments, the core  102  includes one or more tapering sections so that the core  102  is able to fit within and extend into the tube  104 . For example, the distal section of the core  102  may be ground so as to progressively taper to a smaller diameter at the distal end. In this example, the core  102  and the tube  104  have substantially similar outer diameters at the attachment point  103  where they adjoin and attach to one another. 
     The tube  104  is coupled to the core  102  (e.g., using adhesive, soldering, and/or welding) in a manner that allows torsional forces to be transmitted from the core  102  to the tube  104  and thereby to be further transmitted distally by the tube  104 . A medical grade adhesive may be used to couple the tube  104  to the core wire  102  at one or more points (e.g., including attachment point  103 ). A medical grade adhesive/polymer may also be used at the distal end of the device and to form an atraumatic covering  120 . 
     As explained in more detail below, the tube  104  is micro-fabricated to include a plurality of cuts. The cuts are arranged to form a cut pattern which beneficially provides for effective shapeability near the distal tip of the guidewire device  100  while also maintaining good torquability. For clarity, the cut pattern is not shown in  FIGS. 1 and 2 . Examples of cut patterns which may be utilized in the tube  104  are shown in  FIGS. 3 through 8 . 
     In some embodiments, the proximal section  110  of the guidewire device  100  extends proximally to a length necessary to provide sufficient guidewire length for delivery to a targeted anatomical area (not shown). The proximal section  110  typically has a length ranging from about 50 to 300 cm (about 19.69 to 118.11 inches). The proximal section  110  may have a diameter of about 0.36 mm (about 0.014 inches), or a diameter within a range of about 0.20 to 3.175 mm (about 0.008 to 0.125 inches). The distal section  112  of the core  102  may taper to a diameter of about 0.051 mm (about 0.002 inches), or a diameter within a range of about 0.025 to 1.27 mm (about 0.001 to 0.050 inches). In some embodiments, the tube  104  has a length within a range of about 3 to 100 cm (about 1.18 to 39.37 inches). The tube  104  may be formed from and/or include a superelastic material such as nitinol. Alternatively, the tube  104  may be formed from and/or include a linear elastic material (e.g., with a recoverable strain of at least about 6%). The portion of the device extending distally beyond the tube  104  (referred to as the tip  106 ) may measure about 0.5 to 5 cm in length, or about 1 to 3 cm in length. 
     In some embodiments, the distal section  112  of the core  102  tapers to a round cross-section. In other embodiments, the distal section  112  of the core  102  has a flat or rectangular cross-section. The distal section  112  may also have another cross-sectional shape, such as another polygon shape, an ovoid shape, an erratic shape, or combination of different cross-sectional shapes at different areas along its length. 
     Typically, a user will shape the distal end of the guidewire device  100  by manually bending, twisting, or otherwise manipulating the distal 1 cm to 3 cm (approximately) of the guidewire device  100  to a desired shape. The illustrated guidewire device  100  includes a distal tip  106  which extends distally beyond the tube  104 . The tip  106  is configured to be shapeable so that an operator may manually bend, twist, or otherwise manipulate the tip  106  to a desired shape. In some embodiments, the tip  106  includes one or more shapeable components formed from stainless steel, platinum, and/or other shapeable materials. In preferred embodiments, the tip  106  includes one or more components formed from a material that exhibits work hardening properties, such that the tip, when shaped (i.e., plastically deformed), provides a higher elastic modulus at the shaped sections than prior to being shaped. 
     An inner coil  114  is positioned partially within the tube  104  upon at least a portion of the distal section  112  of the core  102 . The inner coil  114  extends distally beyond the tube  104  to form part of the tip  106 . The inner coil  114  is preferably formed from one or more radiopaque materials, such as platinum group, gold, silver, palladium, iridium, osmium, tantalum, tungsten, bismuth, dysprosium, gadolinium, and the like. Additionally, or alternatively, the coil  114  may be at least partially formed from a stainless steel or other material capable of effectively holding shape after being bent or otherwise manipulated by a user. 
     In the illustrated embodiment, the inner coil  114  is disposed at or near the distal end of the device and extends a distance proximally toward the attachment point  103 . In the illustrated device, the majority of the length of the inner coil  114  extends distally beyond the tube  104 . In other embodiments, the inner coil  114  may extend farther proximally. The inner coil  114  may extend from the distal end by 1, 2, 4, 6, 8, 10, 12, 15, 20, 25, 30, or 35 cm, or may extend a distance within a range defined by any two of the foregoing values. 
     In some embodiments, the section of the inner coil  114  extending distally beyond the tube  104  may be formed from a different material than more proximal sections of the inner coil  114 . For example, the distal section of the inner coil  114  may be formed from stainless steel and/or other materials primarily selected to provide effective shapeability, while the proximal sections of the inner coil  114  are formed from platinum or other materials primarily selected to provide effective radiopacity. In some embodiments, the inner coil  114  is formed as one integral piece. In other embodiments, the inner coil  114  includes a plurality of separate sections positioned adjacent to one another and/or interlocked through intertwining coils. Such separate segments may additionally or alternatively be soldered, adhered, or otherwise fastened to one another to form the complete inner coil  114 . 
     Although the illustrated embodiment shows a space between the outer surface of the inner coil  114  and the inner surface of the tube  104 , it will be understood that this is done schematically for ease of visualization. In some embodiments, the inner coil  114  is sized to fill and pack a greater proportion of the space between the core  102  and the tube  104 . For example, the inner coil  114  may be sized so as to abut both the outer surface of the core  102  and the inner surface of the tube  104 . Some embodiments may include a space between the core  102  and the tube  104  for at least a portion of the section of the guidewire device  100  where the tube  104  and the core  102  are co-extensive. 
     The portion of the inner coil  114  disposed within the tube  104  may beneficially function to pack the space between the core  102  and the tube  104  so as to align the curvature of the distal section  112  of the core  102  with the curvature of the tube  104 . For example, when a curvature is formed in the tube  104 , the closely packed segments of the inner coil  114  function as a packing between the tube  104  and the distal section  112  to impart the same curvature to the distal section  112 . In contrast, a core of a guidewire device omitting such packing, may not follow the same curve as the tube but may extend until abutting against the inner surface of the tube before being forced to curve. 
     As shown, the tip  106  extends further distally than the tube  104 . The illustrated configuration beneficially allows the tip  106  to be shaped to a desired position relative to the tube  104  and the rest of the guidewire  100  and to remain in the shaped position for a sufficiently extended period of time. In contrast to a guidewire device relying on shapeability of a tube or upon shapeable components disposed more fully within a tube, the illustrated tip  106  is able to maintain a shaped configuration without being subjected to counteracting forces imparted by the tube  104  itself. 
     In addition, as described more fully below, the tube  104  may include a cut pattern which maintains effective torquability while also providing sufficient flexibility at the distal region of the tube  104  so as to avoid disrupting the custom shape of the tip  106 . In preferred embodiments, the shapeable distal section of the core has a stiffness that is able to withstand an expected bending force from the tube acting upon the distal section of the core after it has been shaped. In some embodiments, the shapeable distal section of the core is formed from a material or combination of materials providing a modulus of elasticity that is about 1.5 to 4 times greater, or about 2 to 3 times greater than the modulus of elasticity of the material(s) used to form the tube. 
     In contrast to the illustrated embodiments, a guidewire device which relies on shaping of a tube to provide a desired distal tip shape will not be capable of holding the shaped configuration or will only be capable of holding the shaped configuration for a relatively short period of time. This degradative effect on the shaped tip happens at least in part because tube structures are typically formed from nitinol or other superelastic materials. Such tubes will be biased, upon being bent or shaped, toward their original (e.g., straight) position, and will impart recovery forces against any shapeable internal components, resulting in deformation and a loss of the customized shape of the tip. 
     Often, for example, a guidewire that distally terminates with a tube structure or that otherwise substantially relies on bending of the tube structure to shape the tip will have a shaped tip prior to deployment. However, the shaped tip will be lost or degraded during use of the guidewire as the superelastic tube flexes toward its original shape in opposition to the desired tip shape. In contrast, embodiments described herein provide tips capable of being shaped without being subjected to deforming recovery forces of adjoining components of the guidewire device. 
     In the illustrated guidewire device  100 , an outer coil  118  overlies the distally extending section of the inner coil  114 . The inner coil  114  and outer coil  118  may use similar or dissimilar coil characteristics (coil wire diameter, pitch, etc.). Typically, the outer coil  118  is formed from larger diameter coil wiring as compared to the wire diameter of the inner coil  114 . The outer coil  118  may be formed from stainless steel or other suitable material capable of providing suitable shapeability. 
     Cut Patterns 
       FIGS. 3 through 8  illustrate exemplary embodiments of tube cut patterns that may be utilized in one or more of the guidewire device embodiments described herein. For example, the tube  104  of the embodiment shown in  FIGS. 1 and 2  may be cut according to one or more of the configurations shown in  FIGS. 3 through 8 . 
     Cut patterns are referred to herein according to the number of axially extending beams disposed between each pair of adjacent circumferentially extending rings.  FIGS. 3 and 4  illustrate “one-beam” cut patterns,  FIGS. 5 and 6  illustrate “two-beam” cut patterns, and  FIG. 7  illustrates a “three-beam” cut pattern. Other embodiments may include more than three beams between each pair of adjacent rings (e.g., a four-beam cut pattern, five-beam cut pattern, etc.). 
     The tube structure  304  illustrated in  FIG. 3  includes a single beam  332  disposed between each pair of adjacent rings  334 . Pairs of adjacent beams may alternate by 180 degrees, as shown. Additionally, or alternatively, sections may include beams positioned on a single side along a length of the tube, as shown by the beams  432  and rings  434  of the tube  404  of  FIG. 4 . 
     The tube structure  504  illustrated in  FIG. 5  includes a pair of circumferentially opposing beams  532  disposed between each pair of adjacent rings  534 . The corresponding beams  532  in each pair may be symmetrically circumferentially spaced (i.e., by about 180 degrees) as shown by  FIG. 5 . Alternatively, the corresponding beams may be circumferentially non-symmetric, as shown by the beams  632  and rings  634  of the tube  604  of  FIG. 6 . The tube structure  704  illustrated in  FIG. 7  includes a triad of beams  732  disposed between each pair of adjacent rings  734 . The corresponding beams in each triad may be symmetrically circumferentially spaced (i.e., by about 120 degrees) as shown, or may be positioned according to some non-symmetric arrangement. 
     Generally, the higher the number of beams left between each pair of adjacent rings, the relatively greater the stiffness of the tube. Cut patterns may therefore be selected to provide a desired flexibility profile along the length of the tube. Cut spacing, width, and/or depth may also be varied to provide desired flexibility characteristics. For example, one tube configuration can include a proximal section with relatively lower flexibility and relatively higher torquability that rapidly progresses to a distal section with relatively higher flexibility and relatively lower torquability. Beneficially, the flexibility provided by such cut patterns can minimize or prevent the tube from deforming the shape of the internal structures of the guidewire (e.g., the core) so that a customized shape of the tip can be better formed and maintained. 
     A section of tube having a two-beam cut pattern with substantially circumferentially equally spaced beams (as in  FIG. 5 ) will typically have relatively higher ability to transmit torque and relatively lower flexibility, while a section of tube having non-symmetrically spaced beams (as in  FIG. 6 ) will typically have a torque transmissibility and flexibility between that of a symmetrically spaced beam pattern and a one-beam pattern. The less circumferentially symmetric the corresponding pair of beams are positioned, the closer together circumferentially the resulting beams will be, and therefore the more similar the non-symmetric two-beam cut will be to a one-beam cut pattern. Such a non-symmetric two-beam pattern may therefore be used as a transition between a symmetric two-beam pattern and a one-beam pattern. 
     The cut patterns may form “segments” of repeating structural units along a length of the tube. In a typical one-beam embodiment, a single segment can be defined as a first beam  332  disposed between two adjacent rings  334  (one proximal ring and one distal ring) and a second opposing beam  332  extending from the distal ring and being rotationally offset by about 180 degrees from the first beam  332 . Likewise, in a typical two-beam embodiment, a single segment can be defined as a first pair of beams  532  disposed between two adjacent rings  534  (one proximal ring and one distal ring) and a second pair of beams  532  extending from the distal ring and being rotationally offset from the first pair of beams by about 90 degrees. Likewise, in a typical three-beam embodiment, a single segment can be defined as a first triad of beams  732  disposed between two adjacent rings  734  (one proximal ring and one distal ring) and a second triad of beams  732  extending from the distal ring and being rotationally offset from the first triad by about 60 degrees. 
       FIG. 8  illustrates a tube  804  having a plurality of beams  832  and rings  834 . The illustrated cut pattern includes a rotational offset applied at each successive segment of the tube  804  to minimize preferred bending directions in the tube. As used herein, a “rotational offset” is the angular rotation between two adjacent segments. A rotational offset is therefore applied from one segment to the next, even though individual cuts within a segment may also be offset from one another. 
     As shown, the cuts may be arranged to form a substantially consistent rotational offset from one segment to the next. The illustrated cut pattern shows a rotational offset of about 5 degrees from one segment to the next. When multiple successive segments having such an angular offset are formed, the resulting pattern of beams along a sufficient length of the tube  804  wraps around the axis of the tube  804  in a continuously rotating helical pattern. The angular offset may be about 5, 15, 30, 45, 60, 75, 80, or 85 degrees. In some embodiments, the angular offset is applied at each successive segment. In other embodiments, a plurality of successive segments are disposed next to one another without an offset before the angular offset is applied. 
     The illustrated example shows a two-beam cut pattern with a series of rotational offsets. It will be understood, however, that the same principles may be applied to other cut patterns, such as a one-beam cut pattern, three-beam cut pattern, or cut pattern having greater than three beams per pair of adjacent rings. In preferred embodiments, each successive cut or sets of cuts (e.g., every second cut, third, fourth, etc.) along the length of a given section is rotationally offset by about 1, 2, 3, 5, or 10 degrees, or is offset by about 1, 2, 3, 5, or 10 degrees off from 180 degrees in a one-beam pattern, 1, 2, 3, 5, or 10 degrees off from 90 degrees in a two-beam pattern, 1, 2, 3, 5, or 10 degrees off from 60 degrees in a three-beam pattern, and so on for patterns having a higher beam count. These rotational offset values have beneficially shown good ability to eliminate flexing bias. 
     The separate components and features of the cut patterns shown in  FIGS. 3 through 8  may be combined to form different tube configurations. For example, some tubes may be configured so as to have a section of two-beam cuts which transitions to a section of one-beam cuts. 
     Tip Variations 
       FIGS. 9 through 11  illustrate embodiments of various distal tip configurations that may be utilized with one or more of the embodiments described herein.  FIG. 9  illustrates a continuous diameter tip configuration. Where the coil  918  surrounding the tapering core  902  has a substantially continuous diameter.  FIG. 10  illustrates a stepped tip configuration where an outer coil  1018  positioned over the core  1002  has a substantially continuous diameter. A smaller diameter inner coil  1014  is positioned so as to extend further distally than the outer coil  1018  to provide a step-wise change in diameter of the tip.  FIG. 11  illustrates a tapered tip configuration where the coil  1118  is tapered so as to match a taper of at least a portion of the core  1102 . The tip embodiments illustrated in  FIGS. 9 through 11  may be combined with any of the guidewire device embodiments described herein. For example, a desired tip configuration may be selected so as to provide desired shapeability and/or flexibility characteristics for a given guidewire application. 
     The terms “approximately,” “about,” and “substantially” as used herein represent an amount or condition close to the stated amount or condition that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount or condition that deviates by less than 10%, or by less than 5%, or by less than 1%, or by less than 0.1%, or by less than 0.01% from a stated amount or condition. 
     Elements described in relation to any embodiment depicted and/or described herein may be combinable with elements described in relation to any other embodiment depicted and/or described herein. For example, any element described in relation to a tube section of any of  FIGS. 3 through 8  and/or any element described in relation to a tip configuration of any of  FIGS. 9 through 11  may be combined and used with the guidewire device of  FIGS. 1 and 2 . In any of the foregoing combinations, the distal tip of the core wire may be rounded, flat, or another shape. 
     The present invention may be embodied in other forms, without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.