Patent Description:
Embodiments of the instant disclosure address a weakness of both industry standard guidewire types to provide both tactile feedback and easy device passage. No currently available guidewire provides both of these features. Rather, hybrid guidewires offer improved tactile feedback to increase control and positioning accuracy within the bodily lumen, but do not allow for easy passage of surgical devices thereover. On the other hand, hydrophilic guidewires offer easy passage of surgical devices thereover, but lack tactile feedback. Consequently, the embodiments of the instant disclosure address a need in the art currently unmet.

It is a first aspect of the present invention to provide a guidewire comprising a hydrophilic surface coating encasing a metal coil and a majority length of a core to form a distal closed tip, the metal coil circumscribing the core along a predetermined length, the core extending longitudinally beyond the metal coil in both a proximal direction and a distal direction, wherein a proximal section of the guidewire includes a hydrophobic surface coating over a minority length of the core.

In a more detailed embodiment of the first aspect, at least a portion of the core extending in the distal direction beyond the metal coil includes a silane coating. In yet another more detailed embodiment, the core includes a frustroconical shape that extends beyond the metal coil in the distal direction. In a further detailed embodiment, the silane coating is separated from the hydrophilic surface coating by a thermoplastic polymer layer. In still a further detailed embodiment, the thermoplastic polymer layer is radiopaque. In a more detailed embodiment, the thermoplastic polymer layer comprises a polycaprolactone based polyurethane elastomer. In a more detailed embodiment, the polycaprolactone based polyurethane elastomer comprise tungsten loaded pellethane. In another more detailed embodiment, the core is coated in an epoxy primer. In yet another more detailed embodiment, the epoxy primer comprises a mixture of an epoxy resin, an epoxy polyamine adduct, and a glycidyl ester. In still another more detailed embodiment, the epoxy primer is adjacent the hydrophobic surface coating.

In yet another more detailed embodiment of the first aspect, an overall length of the guidewire is between <NUM> and <NUM> (ten and two hundred inches). In yet another more detailed embodiment, the core has a median diameter between approximately <NUM> (<NUM> inches) and <NUM> (<NUM> inches). In a further detailed embodiment, the distal closed tip is atraumatic. In still a further detailed embodiment, the core is at least one of solid and hollowed. In a more detailed embodiment, the core comprises an alloy of nickel, titanium, and cobalt. In a more detailed embodiment, the core includes a cross-sectional shape comprising at least one of circular, oblong, and rectangular. In another more detailed embodiment, the core includes a tapered section. In yet another more detailed embodiment, the core includes a frustroconical section. In still another more detailed embodiment, the guidewire further includes a silane coating interposing the core and the hydrophilic surface coating.

In a more detailed embodiment of the first aspect, the silane coating is spaced from the hydrophilic surface coating by a thermoplastic polymer layer. In yet another more detailed embodiment, the thermoplastic polymer layer is radiopaque. In a further detailed embodiment, the thermoplastic polymer layer comprises a polycaprolactone based polyurethane elastomer. In still a further detailed embodiment, the polycaprolactone based polyurethane elastomer comprise tungsten loaded pellethane. In a more detailed embodiment, the core is coated in an epoxy primer in the form of two ring-shaped coatings spaced apart from one another. In a more detailed embodiment, each of the two ring-shaped coatings is no greater than <NUM> (ten inches) in length. In another more detailed embodiment, the metal coil comprises stainless steel. In yet another more detailed embodiment, the metal coil has a radial cross-section that is rectangular in shape.

It is a second aspect of the present invention to provide a guidewire comprising: (a) a first section comprising a core, a hydrophilic layer, and a polymer layer interposing the core and the hydrophilic layer; (b) a second section comprising the core, the hydrophilic layer, and a metal coil interposing the core and the hydrophilic layer; and, (c) a third section comprising the core and a hydrophobic layer, where the hydrophilic layer and the hydrophobic layer comprise an exterior surface of the guidewire; and the hydrophobic layer comprises more than ninety percent of the exterior surface.

Disclosed is as well a method of fabricating a guidewire comprising: (a) mounting a metal coil over a core so that the metal coil circumscribes the core along a predetermined length, the core extending longitudinally beyond the metal coil in both a proximal direction and a distal direction; (b) encasing the metal coil and a majority of the core in a hydrophilic exterior surface layer so a distal tip of the guidewire is closed; and, (c) forming a hydrophobic exterior surface over a minority of the core.

In a more detailed embodiment, the method further includes shaping the core to create a tapered distal segment. In yet another more detailed embodiment, the method includes shaping the core to create the tapered distal segment include grinding the core to remove material from the core. In a further detailed embodiment, the method includes forming the hydrophobic exterior surface over the minority of the core includes heat shrinking a hydrophobic tube over the minority of the core. In still a further detailed embodiment, the hydrophobic tube is heat shrinked over a proximal-most section of the core. In a more detailed embodiment, the hydrophobic tube comprises polytetrafluoroethylene. In a more detailed embodiment, the method further includes applying an epoxy primer to the core so as to interpose the core and metal coil. In another more detailed embodiment, the epoxy primer is applied to form two rings around the core that are spaced apart from one another. In yet another more detailed embodiment, the method further includes heat treating the applied epoxy primer to bond the core to the metal coil where the epoxy primer was applied. In still another more detailed embodiment, the method further includes applying a silane primer to a distal most portion of the core.

In yet another more detailed embodiment, the method further includes curing the applied silane primer via a heat treatment. In yet another more detailed embodiment, the method includes encasing the metal coil and a majority of the core in the hydrophilic coating also includes encasing the silane primer.

Furthermore a method is disclosed of using a guidewire comprising: (a) inserting a closed distal tip of a guidewire into a bodily lumen, the guidewire comprising a hydrophilic surface coating encasing a core and a metal coil along a longitudinal length of the hydrophilic surface coating to form a distal closed tip, the metal coil circumscribing the core along a predetermined length, the core extending longitudinally beyond the metal coil in both a proximal direction and a distal direction, wherein a proximal section of the guidewire includes a hydrophobic surface coating; (b) repositioning the guidewire within the bodily lumen to reach an end location for the closed distal tip while receiving real-time images from a radiation imager that depict a relative location of the distal tip with respect to a section of the bodily lumen; (c) inserting a medical instrument over the guidewire post the distal tip reaching the end location; (d) carrying out a medical procedure using the medical instrument; and, (e) withdrawing the guidewire from the bodily lumen post insertion of the medical instrument.

The exemplary embodiments of the present disclosure are described and illustrated below to encompass exemplary guidewires, methods of fabricating the same, as well as methods of using the same. Of course, it will be apparent to those of ordinary skill in the art that the embodiments discussed below are exemplary in nature and may be reconfigured without departing from the scope of the present invention. However, for clarity and precision, the exemplary embodiments as discussed below may include optional steps, methods, and features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present invention.

Referencing <FIG>, a first exemplary guidewire <NUM> is configured for insertion into a bodily lumen such as, without limitation, a ureter. In this exemplary embodiment, the guidewire <NUM> may have an overall length of between <NUM> to <NUM> (ten to two hundred inches). For purposes of exemplary explanation only, the guidewire <NUM> will be described as having an overall length of approximately <NUM> (fifty-nine inches). The guidewire <NUM> may have a circular or rounded cross-sectional profile (i.e., axial profile) taken perpendicular to the dominant longitudinal dimension (i.e., the lengthwise dimension). By way of example, an outside diameter of the guidewire <NUM> may be between <NUM> to <NUM> (<NUM> to <NUM> inches), and more specifically range between <NUM> and <NUM> (<NUM> and <NUM> inches). For purposes of exemplary explanation only, the guidewire <NUM> will be described as having generally a circular axial profile with an outside diameter between approximately <NUM> - <NUM> (<NUM>-<NUM> inches). By way of example, the guidewire <NUM> may be comprised of differing layers and constituents along its length that may correspondingly change the cross-sectional make-up of the guidewire. As a result, the following discussion of the guidewire <NUM> constituents is broken down into a series of guidewire sections that are seamlessly coupled to one another between a distal tip (inserted first into the bodily lumen) and the proximal end.

Referring specifically to <FIG>, a first section <NUM> includes a distal tip <NUM> and a predetermined length extending proximally away from the tip. By way of example, the distal tip may comprise an atraumatic tip, though this is not a necessity. The first section <NUM> comprises a core <NUM> that may be solid or partially hollowed. In exemplary form, the core <NUM> comprises an alloy of nickel, titanium, and cobalt having a circular axial profile that need not be constant along the axial length of the first section <NUM>. More specifically, the core <NUM> may taper in shape so that, in the case of a circular or rounded axial profile, the outside circumference of the core material decreases between the proximal portion of the first section <NUM> and the distal tip <NUM>. By way of further example, the core <NUM> may have a circular axial profile that gradually tapers until reaching a blunt distal end <NUM>, thereby embodying a frustoconical shape.

A second constituent of the first section <NUM> comprises a silane coating <NUM> applied over the exterior of the core <NUM> that is operative to encapsulate the distal end <NUM>. In this exemplary embodiment, the core <NUM> may be dipped in liquid silane that cures to form the coating <NUM>. Alternatively, the core <NUM> may be sprayed with a liquid silane that dries to form the coating <NUM>. Those skilled in the art will understand the plethora of techniques that may be used to form a silane coating <NUM> over a core <NUM>, with such techniques being omitted only in furtherance of brevity, and each of which shall fall within the scope of the instant disclosure. By way of example, the silane coating <NUM> may comprise any silane composition operative to promote adherence between the core <NUM> and a top coating <NUM>.

By way of example, the top coating <NUM> may comprise a radiopaque thermoplastic polymer operative to encapsulate the distal end <NUM> of the core material, as well as the silane coating <NUM>. By way of further example, the top coating <NUM> may comprise a polyester polycaprolactone based polyurethane elastomer such as, without limitation, tungsten loaded PELLETHANE, available from The Lubrizol Corporation. By making the top coating <NUM> radiopaque, the first section <NUM> is relatively impenetrable to the transmission of radiation, thus creating a clearly visible darkened image when within the field of view for X-ray, fluoroscopy, CT, or other radiation imaging technologies.

The top coating <NUM> is itself encapsulated by a surface coating <NUM>. In exemplary form, the surface coating <NUM> may comprise a hydrophilic coating, where the distal end of the coating comprises the distal tip <NUM> of the guidewire. In exemplary form, the first section <NUM> may have a length of approximately <NUM> (two inches).

Referring to <FIG>, <FIG>, the first section <NUM> may be seamlessly bonded to a second section <NUM> that is operative to form a transition between a third section <NUM> and the first section <NUM>. The second section <NUM> may include three of the same constituents as the first section <NUM>, namely the core <NUM>, the top coating <NUM>, and the surface coating <NUM>, in addition to a metal coil <NUM> positioned adjacent to the top coating <NUM>. In exemplary form, the metal coil <NUM> provides micro ridges and valleys when covered by the top coating <NUM>, which is operative to provide increased traction or a coefficient of friction greater than the first section. As will be discussed in more detail hereafter, a heat treatment may be applied to the guidewire <NUM> resulting in a portion of the top coating <NUM> diffusing beyond the first section <NUM> and into the second section <NUM> between the coil <NUM> turns and the core <NUM>. In this fashion, post heat treatment, a thin portion of the top coating <NUM> sits atop and/or protrudes between the turns of the coil <NUM>.

In this exemplary embodiment, the metal coil <NUM> may comprise stainless steel (such as a 304V alloy) or any other biologically inert/compatible or acceptable metal or metal alloy. The turns of the metal coil <NUM> may have a helical shape with an outer diameter substantially constant and ranging between <NUM> to <NUM> (<NUM> to <NUM> inches), and more specifically range between <NUM> and <NUM> (<NUM> and <NUM> inches). The metal comprising the turns of the coil <NUM> may have a circular, rounded, or other shaped cross-section. By way of example, the coil turns may have a square or rectangular cross-section. In other words, the metal wire comprising the coil <NUM>, before it is coiled, may have a square or rectangular cross-section. In exemplary form, the second section <NUM> may have a length of approximately <NUM> (<NUM> inches).

Referencing <FIG>, <FIG>, post the second section <NUM> is the third section <NUM>. This third section <NUM> may include the core <NUM> and, rather than having a silane coating <NUM> as in the first section <NUM>, may include an epoxy primer coating <NUM> over top of the core <NUM> along a predetermined length of a distal portion and the proximal most portion. By way of example, this predetermined length may be <NUM> (<NUM> inches) so that a distal portion has a <NUM> (<NUM> inch) length epoxy primer coating <NUM> and the proximal most <NUM> (<NUM> inch) length includes the epoxy primer coating <NUM> directly over the core <NUM>. In exemplary form, the epoxy primer coating <NUM> may comprise a mixture of an epoxy resin, an epoxy polyamine adduct, and a glycidyl ester. The same metal coil <NUM> that may be present in the second section <NUM> may be present in the third section <NUM> and overlie the epoxy primer coating <NUM> (where present) and otherwise overlie and directly contact the core <NUM>. The same surface coating <NUM> may be applied over the metal coil <NUM>.

Referencing <FIG>, the vast majority of the length of the third section <NUM> may omit the epoxy primer coating <NUM>. In such a configuration, the core <NUM> is circumscribed by the metal coil <NUM>, which itself is covered with the surface coating <NUM> to encapsulate the metal coil and core material. In this configuration, the metal coil <NUM> may be free floating over the core <NUM> thereby allowing the metal coil to move independent of the core <NUM>. In exemplary form, the third section <NUM> may have a length of approximately <NUM> (<NUM> inches).

Referencing <FIG>, <FIG>, a fourth section <NUM> may seamlessly abut the third section <NUM> opposite the second section <NUM>. This fourth section <NUM> may include the same core <NUM>, yet omit the epoxy primer coating <NUM>, the metal coil <NUM>, and the surface coating <NUM>. In exemplary form, the core <NUM> of this fourth section may include a hydrophobic coating <NUM>. This hydrophobic coating <NUM> may comprise any number of hydrophobic materials such as, without limitation, polytetrafluoroethylene (PTFE). In exemplary form, the hydrophobic coating <NUM> may be applied in the form of a PTFE tube that is heat-shrinked to precisely circumscribe and contact the adjacent core <NUM>. In this exemplary embodiment, the fourth section may have a length of <NUM> (<NUM> inches). By way of further example, the first section <NUM> has a lesser coefficient of friction than the second section <NUM>, where the second section has a lesser coefficient of friction than the fourth section <NUM>.

Turning to <FIG>, an exemplary process <NUM> for producing the exemplary guidewire <NUM> is provided. Specifically, fabrication of the foregoing guidewire <NUM> may commence at step <NUM> by forming the core <NUM> into a desired shape. By way of example, a predetermined length of core <NUM> (such as <NUM> (<NUM> inches)), which length may vary depending upon the desired length of the guidewire, may be unwound from a spool of core material. The core <NUM> may have a generally uniform cross-section along its dominant longitudinal length that may be circular, oblong, or another shape. In exemplary form, the uniform cross-sections of the core may range between <NUM> and <NUM> (<NUM> and <NUM> inches) in diameter and, more specifically, may range between <NUM> - <NUM> (<NUM>-<NUM> inches) in diameter. This generally uniform cross-section may be supplemented by longitudinal lengths that are tapered or otherwise varied to change the overall width of the guidewire <NUM> and/or to change the proportion of the cross-section occupied by the core <NUM>. By way of further example, the core <NUM> may comprise a cylindrical shape having a circular axial profile that is tapered along a predetermined length to provide a frustoconical tip. This tapering process may be part of step <NUM> and may be carried out by grinding or any other material removal process. In exemplary form, the tapering may occur on a <NUM> (<NUM> inch) distal end of the core <NUM>.

Post forming the core <NUM> into a desired shape in step <NUM>, a subsequent step <NUM> may include formation of the hydrophobic coating <NUM> at a proximal end of the core material. Specifically, a hydrophobic tube of PTFE may be positioned to circumscribe a proximal section (or end) of the core <NUM>. Post positioning of the PTFE tube around the core <NUM>, heat is applied to the tube, which causes the tube to shrink and form fit to the exterior of the core <NUM>, thereby providing a hydrophobic coating <NUM>. In exemplary form, the resulting hydrophobic coating <NUM> may have a radial thickness ranging between <NUM> and <NUM> (<NUM> and <NUM> inches). More specifically, the hydrophobic coating may have a radial thickness of approximately <NUM> (<NUM> inches).

Before, during, or after formation of the hydrophobic coating <NUM> about the core <NUM>, at step <NUM>, the metal coil <NUM> is slid over a distal end of the core <NUM> until a proximal end of the metal coil abuts an intended or actual distal end of the hydrophobic coating <NUM>. The length of the metal coil <NUM> may be chosen so that a distal section of the core <NUM> is not circumscribed by the coil. In exemplary form, the metal coil <NUM> may comprise any biocompatible metal or metal alloy including, without limitation, stainless steel 304V. It should also be known that the cross-section of each metal strand wound to form the coil may have a cross-sectional shape other than circular or oblong. For example, the metal strand may have a square or rectangular cross-sectional shape.

Before, during, or after positioning the metal coil <NUM> around the core <NUM>, at step <NUM>, an epoxy primer coating <NUM> is applied to predetermined portions of the core <NUM> to eventually interpose the core and metal coil. During step <NUM>, an epoxy primer may be applied to a predetermined length of the core <NUM> (such as, without limitation, <NUM> (<NUM> inches)) immediately distal to the intended or actual end location of the hydrophobic coating <NUM>, as well as to a more distal location located about six inches (about <NUM> centimeters) from the distal tip of the core. Post application of the epoxy primer coating <NUM> and the metal coil <NUM>, a heat treatment step <NUM> may be carried out to bond the metal coil <NUM> to the core <NUM> by curing the epoxy primer coating <NUM>.

At step <NUM>, a distal-most section (e.g., about <NUM> (two inches)) of the core <NUM> may be dipped in a silane primer or have a silane primer spray applied thereto. Heat is applied to the wet silane composition post application to cure the silane and form a coating <NUM> over the distal core <NUM>.

After the silane coating <NUM> is formed in step <NUM>, a top coating step <NUM> may be carried out. In this step <NUM>, a polymer coating <NUM> may be applied over the silane coating <NUM> by dipping or spraying a liquid polymer composition to the distal-most section (e.g., about <NUM> (two inches)) of the core <NUM>. Alternatively, the polymer coating <NUM> may be in the form of a tube wrapped in a disposable peel-away heat shrink tube, which are both applied over the silane coating <NUM>. In exemplary form, the polymer composition may comprise a radiopaque material, when cured, such as, without limitation, tungsten loaded pellethane. Post application of the polymer coating <NUM> over the silane coating <NUM>, a heat treatment may be carried to bond the polymer coating <NUM> to the silane coating <NUM> and core <NUM>. During such a heat treatment, portions of the polymer coating <NUM> may flow into communication with and under the metal coil <NUM> and become entrained within the coils, thereby bonding the polymer coating <NUM> to the metal coil <NUM>. Post heat treatment, in the context where a peel-away heat shrink tube is utilized, the disposable heat shrink tube may be peeled away to leave only the polymer coating <NUM> as the outermost surface of the guidewire <NUM>.

At step <NUM>, a hydrophilic surface coating126 is applied over the complete length of the polymer top coating <NUM> and the metal coil <NUM>, but need not be applied over the hydrophobic coating <NUM>. Application of the hydrophilic surface coating and any resulting cure sub-steps may be fashioned to arrive at a guidewire with an atraumatic distal tip <NUM>. In exemplary form, the hydrophilic surface coating may have a radial thickness of between <NUM> and <NUM> (<NUM> and <NUM> inches) and, more specifically have a radial thickness of approximately <NUM> (<NUM> inches).

Turning to <FIG>, an exemplary process <NUM> for using the exemplary guidewire <NUM> is disclosed. Specifically, the distal tip <NUM> may be inserted at step <NUM> into the bodily lumen of a mammal. Post insertion of the distal tip <NUM>, an operator of the guidewire <NUM> may twist and manipulate the guidewire at step <NUM> to force more of the guidewire deeper into the bodily lumen until the distal tip reaches a desired position within the bodily lumen. As part of twisting and manipulating the guidewire, a fluoroscopic unit (known to those skilled in the art) may be utilized by the operator at step <NUM> to provide visual indications of the location of the distal tip <NUM> relative to the bodily lumen.

As discussed previously, the first section <NUM> of the guidewire <NUM> includes a radiopaque polymer coating <NUM> (e.g., tungsten loaded pellethane) that, under fluoroscopy or other radiation-based imager, shows up as a darkly shaded object contrasting against the lighter shades of the bodily lumen. Consequently, the operator of the guidewire <NUM> can redirect the guidewire in real-time responsive to real-time images generated from a radiation-based imager. This same imager may be used by the operator to identify an appropriate termination location for the distal tip. Upon reaching the appropriate termination location for the distal tip within the bodily lumen, the operator may move to step <NUM> to thread the appropriate surgical instrument over the guidewire <NUM>.

In exemplary form, the surgical instrument threaded over the guidewire <NUM> may vary greatly depending upon the bodily lumen the guidewire is located within as well as the intended surgical procedure. Consequently, any surgical device that may be threaded over a guidewire is implicated herein and within the scope of the intended use of being threaded over the instant guidewire <NUM>. By way of example, in the context of the bodily lumen comprising a ureter, the surgical instrument may comprise a ureteroscope. By way of further example, in the context of the bodily lumen comprising a ureter, the surgical instrument may comprise at least one of a ureteral stent and a ureteral access sheath. It should be understood that the exemplary guidewire <NUM> is not limited to urinary applications. Instead, the exemplary guidewire <NUM> may be used in circulatory procedures including, without limitation, angioplasty procedures. It should be noted that contrary to conventional wisdom, the hydrophilic surface coating <NUM> provides a lower coefficient of friction for sliding surgical instruments thereover than a comparable hydrophobic coating.

Before, during, or post the surgical procedure, an operator of the guidewire <NUM> may pull or otherwise withdraw the guidewire through the bodily lumen including withdrawal of the distal tip <NUM> from the bodily lumen at step <NUM>.

It should also be noted that the exemplary guidewire <NUM> may be disposable or may be used repeatedly for the same or different surgical procedures.

Claim 1:
A guidewire comprising:
a hydrophilic surface coating (<NUM>) encasing a metal coil (<NUM>) and a majority length of a core (<NUM>) to form a distal closed tip (<NUM>), the metal coil (<NUM>) circumscribing the core (<NUM>) along a predetermined length, the core (<NUM>) extending longitudinally beyond the metal coil (<NUM>) in both a proximal direction and a distal direction, wherein a proximal section of the guidewire includes a hydrophobic surface coating (<NUM>) over a minority length of the core.