Abstract:
A wire guide includes a helically wound coil having a proximal end and a distal end. A mandrel is positioned within the helically wound coil and terminates before the distal end of the helically wound coil. First and second safety wires are positioned within the helically wound coil and have proximal ends attached to the mandrel and distal ends attached to the distal end of the helically wound coil. The first and second safety wires are positioned on opposite sides of a distal tip of the mandrel and have contact surfaces facing the distal tip of the mandrel that have a shape other than convex. The interaction between the mandrel tip and the safety wires during a percutaneous vascular procedure inhibit mandrel protrusion and the potential tissue damage associated therewith.

Description:
RELATION TO OTHER PATENT APPLICATION 
       [0001]    This application claims priority to provisional patent application 61/405,768, filed Oct. 22, 2010 with the same title. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates generally to the field of vascular intervention, and more particularly to a wire guide having two safety wires for reducing mandrel protrusion during percutaneous endovascular procedures. 
       BACKGROUND 
       [0003]    Diagnosis and treatment of vascular conditions are commonly performed using percutaneous endovascular procedures, which involve the insertion of a catheter or the like into a blood vessel or artery of the vascular system. Known catheterization procedures include the positioning and use of stents and balloons within constricted vessels or arteries, and the intravenous administration of bloods, drugs, and other fluids. The first step in the performance of these procedures is the establishment of a site through the skin by which access is made to the blood vessel or artery. A wire guide is then introduced into the vessel or artery and advanced to a desired location, often with the assistance of a guide catheter. A working catheter may then be advanced to the desired location over the wire guide in a safe and atraumatic fashion. 
         [0004]    Wire guides typically include an elongate helically wound coil having a mandrel positioned therein for increasing the stiffness of the helically wound coil. The mandrel typically does not extend fully to a distal end of the helically wound coil, to allow increased flexibility at the distal end of the coil. This allows increased maneuverability through convoluted or tortuous pathways within the vascular system. Further, distal ends of the wire guides may be provided with preformed curves to further increase maneuverability of the wire guide into branches of vessels or arteries. Wire guides may also be provided with a single safety wire extending a length of the helically wound coil to reduce the possibility of portions of the helically wound coil breaking lose within a patient, should the helically wound coil unravel. 
         [0005]    It is important for patient safety that a distal tip of the mandrel does not protrude through the helically wound coil while the wire guide is advanced through blood vessels or arteries of the patient. Such mandrel protrusion, which may scrape or puncture the inside of the vessel or artery through which the wire guide is moving, may become more likely when the flexible distal end of the helically wound coil is manipulated through sharp or tortuous curves of the vascular system. 
         [0006]    The present disclosure is directed toward one or more of the problems set forth above. 
       SUMMARY OF THE DISCLOSURE 
       [0007]    In one aspect, a wire guide includes a helically wound coil having a proximal end and a distal end. A mandrel is positioned within the helically wound coil and terminates before the distal end of the helically wound coil. First and second safety wires are positioned within the helically wound coil and have proximal ends attached to the mandrel and distal ends attached to the distal end of the helically wound coil. The first and second safety wires are positioned on opposite sides of a distal tip of the mandrel and have contact surfaces facing the distal tip of the mandrel that have a shape other than convex. 
         [0008]    In another aspect, a method of making a wire guide includes attaching proximal ends of first and second safety wires to opposite sides of a mandrel such that substantially flat contact surfaces or substantially concave contact surfaces of the first and second safety wires face a distal tip of the mandrel. The method also includes inserting the mandrel and the first and second safety wires into a helically wound coil through a proximal end of the helically wound coil such that the mandrel terminates before a distal end of the helically wound coil. The method also includes welding distal ends of the first and second safety wires to the distal end of the helically wound coil. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a sectional view of a wire guide according to one embodiment of the present disclosure; 
           [0010]      FIG. 2  is a sectional view of a wire guide according to another embodiment of the present disclosure; 
           [0011]      FIG. 3  is a cross sectional view of the wire guide of  FIG. 2  taken along lines  3 - 3  according to one embodiment of the present disclosure; 
           [0012]      FIG. 4  is a cross sectional view of the wire guide of  FIG. 2  taken along lines  3 - 3  according to another embodiment of the present disclosure; and 
           [0013]      FIG. 5  is a cross sectional view of the wire guide of  FIG. 2  taken along lines  3 - 3  according to yet another embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIG. 1 , there is shown a first embodiment of a wire guide  100  that may be used in a variety of percutaneous endovascular procedures. The wire guide  100  generally includes a helically wound coil  102  having a proximal end  104  and a distal end  106 . The helically would coil  102  may be made from stainless steel wire, or other similar material, and may be wound from a material having a round or other cross sectional shape. The helically wound coil  102  may be provided in any desired length and may have any outer diameter, suitable for the intended use of the wire guide  100 . The helically wound coil  102  may preferably be coated with a lubricious polymer, such as Teflon, to facilitate smooth movement of the wire guide  100  within a catheter, with which the wire guide  100  is to be used, or a vascular structure of a patient. An inner diameter of the helically wound coil  102  may necessarily be of a size sufficient to house the components described herein. 
         [0015]    A mandrel  108  is positioned within the helically wound coil  102  and, as shown, terminates before the distal end  106  of the helically would coil  102 . Specifically, the mandrel  108  is received within a lumen, or cavity,  110  of the helically wound coil  102  and may extend a majority of a length of the coil  102 . The mandrel  108  may be formed from stainless steel, or other commonly selected material, to provide increased stiffness of a majority of the wire guide  100 , and may include a distal segment  112  that is tapered. The taper may be gradual or abrupt, and may begin at any position along the mandrel  108  from a proximal end  114  of the mandrel  108  to a distal end  116  of the mandrel  108 . 
         [0016]    First and second safety wires  118  and  120  are positioned within the helically wound coil  102  of wire guide  100 . As shown, first and second safety wires  118  and  120  include proximal ends  122  and  124 , respectively, attached to the mandrel  108 , and distal ends  126  and  128 , respectively, attached to the distal end  106  of the helically wound coil  102 . Although the embodiment of  FIG. 1  shows the proximal ends  122  and  124  of the safety wires  118  and  120  attached to the proximal end  114  of the mandrel  108 , it should be appreciated that the proximal ends  122  and  124  may be attached at any position along the length of the mandrel  108 . The distal ends  126  and  128  of the first and second safety wires  118  and  120  and the distal end  106  of the helically wound coil  102  are preferably joined together at a first weldment  130 . The first weldment  130  may be formed using plasma welding or any other well known welding technique. Although welding or soldering may be preferred, it should be appreciated that other means for providing a strong and durable connection are also contemplated, including, the use of adhesives. 
         [0017]    The first and second safety wires  118  and  120  are positioned on opposite sides  132  and  134 , respectively, of a distal tip  136  of the mandrel  108  and have contact surfaces  138  and  140 , respectively, facing the distal tip  136  of the mandrel  108 . The contact surfaces  138  and  140 , which may contact the distal tip  136  of the mandrel  108 , have a shape other than convex. Contemplated shapes, which will be discussed later in greater detail, may be provided only at contact surfaces  138  and  140 , or may extend any length of the first and second safety wires  118  and  120 . As such, each of the first and second safety wires  118  and  120  may have a uniform or a non-uniform cross section throughout its length. 
         [0018]    Preferably, the proximal end  114  of the mandrel  108  and the proximal end  104  of the helically wound coil  102  are joined together at a second weldment  142 , or other similar connection. However, it should be appreciated that the proximal end  114  of the mandrel  108  may be attached to the helically wound coil  102  at another position along the length of the coil  102  or, alternatively, may not be permanently attached to the helically wound coil  102 . It should also be appreciated that the proximal ends  122  and  124  of the first and second safety wires  118  and  120  may attach to one or both of the mandrel  108  and the helically wound coil  102  at the second weldment  142 . 
         [0019]    Turning now to  FIG. 2 , another embodiment of a wire guide according to the present disclosure is shown generally at  200 . Wire guide  200  is similar to wire guide  100  of  FIG. 1  and also includes a helically wound coil  202  having a proximal end  204  and a distal end  206 . However, as shown in  FIG. 2 , a distal segment  207  of the helically wound coil  202  may be curved. As should be appreciated, a variety of preformed shapes may be provided to increase maneuverability of the wire guide  200  into branches of vessels or arteries within a patient. 
         [0020]    A mandrel  208 , which may be similar to mandrel  108  of  FIG. 1 , is positioned within the helically wound coil  202  and terminates before the curved distal segment  207 , also referred to as a preformed curve  209 , of the helically wound coil  202 . The mandrel  208  is received within a lumen  210  of the helically wound coil  202  and may include a distal segment  212  that is tapered, starting at any position along the mandrel  208  from a proximal end  214  of the mandrel  108  to a distal end  216  of the mandrel  208 . 
         [0021]    First and second safety wires  218  and  220  are positioned within the helically wound coil  202  and have proximal ends  222  and  224 , respectively, attached to the mandrel  208  and distal ends  226  and  228 , respectively, attached to the distal end  206  of the helically wound coil  202 . According to the embodiment of  FIG. 2 , the proximal ends  222  and  224  of the first and second safety wires  218  and  220  may be attached to the mandrel  208  at a location that is closer to the distal end  216  than the proximal end  214 . The distal ends  226  and  228  of the first and second safety wires  218  and  220  are preferably attached to the distal end  206  of the helically wound coil  202  at a first weldment  230 . 
         [0022]    In a manner similar to that described with respect to the embodiment of  FIG. 1 , the first and second safety wires  218  and  220  are positioned on opposite sides  232  and  234  of a distal tip  236  of the mandrel  208 , and have contact surfaces  238  and  240  facing the distal tip  236  of the mandrel  208  that have a shape other than convex. Such shapes and the resulting cross sections of first and second safety wires  218  and  220  will be discussed below with reference to  FIGS. 3-5 . 
         [0023]    The proximal end  214  of the mandrel  208  and the proximal end  204  of the helically wound coil  202  may be joined together at a second weldment  242 . Although specific embodiments have been shown, it should be appreciated that numerous modifications or deviations from what is described herein are contemplated. For example, specific materials, shapes, sizes, and attachment means and locations may all vary based on specific use requirements and/or manufacturing constraints. 
         [0024]    According to the embodiment of  FIG. 2 , the first and second safety wires  218  and  220  and preformed curve  209  all occupy a common plane P. Specifically, the first safety wire  218  may occupy an outer curve  244  of the preformed curve  209 , while the second safety wire  220  may occupy an inner curve  246  of the preformed curve  209 . However, alternative orientations are contemplated. 
         [0025]    As stated above, the contact surfaces  138  and  140  of  FIG. 1  and contact surfaces  238  and  240  of  FIG. 2  have shapes other than convex. For ease of explanation, exemplary shapes will be described with reference to the contact surfaces  238  and  240  of  FIG. 2 . However, it should be appreciated that similar shapes may be used for contact surfaces  138  and  140  of  FIG. 1 . 
         [0026]    Turning now to  FIG. 3 , the contact surfaces  238  and  240  may be substantially flat. Specifically, surfaces of the first and second safety wires  218  and  220  may be substantially flat at portions of the safety wires  218  and  220  that face the mandrel tip  236  or, alternatively, may be substantially flat along all or a majority of lengths of the safety wires  218  and  220  facing the mandrel  208 . The first and second safety wires  218  and  220  may contact one or both of the helically wound coil  202  and the mandrel  208  when the wire guide  200  is in use or when the wire guide  200  is not in use. As should be appreciated, safety wires having substantially square or rectangular cross sections may provide a lower profile than safety wires having other cross sections, such as round cross sections, and, thus, may occupy less space within the already limited spatial constraints of the helically wound coil  202 . Further, a portion of the additional space may be utilized by extending the width of the safety wires  218  and  220  relative to the mandrel  208 , such that additional contact surface area is provided for the mandrel  208  to engage. 
         [0027]    Turning now to  FIG. 4 , the contact surfaces  238  and  240  are shown as being substantially concave. By utilizing a shape that is complementary to the round cross section of the mandrel  208 , the mandrel  208  may be urged and, thereafter, maintained within the concave contact surfaces  238  and  240  during movement, such as bending, of the wire guide  200 . Various other shapes, excluding a convex shape, are contemplated for contact surfaces  238  and  240 . However, it should be appreciated that sides opposite the contact surfaces  238  and  240  or, more specifically, sides  260  and  262  of the first and second safety wires  218  and  220 , as shown in  FIG. 5 , may include a substantially convex shape. Such shapes at the opposite sides  260  and  262  of respective contact surfaces  238  and  240  may be useful to maintain first and second safety wires  218  and  220  within the outer curve  244  and inner curve  246 , respectively. Preferably, and as shown, a width of each of the first and second safety wires  218  and  220  is greater than a width of the distal tip  236  of the mandrel  208 . 
         [0028]    An exemplary method of making such a wire guide according to the present disclosure will now be described. For ease of explanation, the exemplary method will be described with reference to  FIG. 2 . However, it should be appreciated that a similar method may be used to make the wire guide  100  of  FIG. 1 . 
         [0029]    According to a first step, the proximal ends  222  and  224  of the first and second safety wires  218  and  220  may be attached to opposite sides  232  and  234  of the mandrel  208  such that substantially flat or substantially concave contact surfaces  238  and  240  of the first and second safety wires  218  and  220 , as depicted in  FIGS. 3-5 , face a distal tip  236  of the mandrel  208 . This attachment step may, for example, include soldering the proximal ends  222  and  224  of the first and second safety wires  218  and  220  to the mandrel  208 . 
         [0030]    The mandrel  208  and the first and second safety wires  218  and  220  may then be inserted into the helically wound coil  202  through the proximal end  204  of the helically wound coil  202  such that the mandrel  208  terminates before the distal end  206  of the helically wound coil  202 . Specifically, this step may include inserting the mandrel  208  and the first and second safety wires  218  and  220  into the helically wound coil  202  such that the mandrel  208  terminates before the distal segment  207 , particularly if the distal segment  207  is to be shaped into a preformed curve  209 . 
         [0031]    The distal ends  226  and  228  of the first and second safety wires  218  and  220  may then be welded to the distal end  206  of the helically wound coil  202 , such as by using a well known plasma welding technique. In addition, the proximal end  214  of the mandrel  208  may be welded to the proximal end  204  of the helically wound coil  202 . 
         [0032]    A final step may include shaping the distal segment  207  of the helically wound coil  202  into the preformed curve  209 . Alternatively, however, the shaping step may be an initial step of the method. If so, it should be appreciated that the mandrel  208  and the first and second safety wires  218  and  220  may be oriented within the helically wound coil  202  such that the first and second safety wires  218  and  220  and the preformed curve  209  occupy a common plane, such as plane P. This step may preferably be performed prior to the welding steps described above. Shaping wire guides is well known in the art and, therefore, will not be described in detail herein. 
         [0033]    Although specific embodiments have been provided, it should be appreciated that various modifications or deviations are contemplated herein. For example, although  FIG. 1  illustrates a wire guide  100  that is single-ended (i.e., includes a mandrel  108  terminating before a distal end  106  of a helically wound coil  102  and includes first and second safety wires  118  and  120  having contact surfaces  138  and  140  that flank a distal tip  136  of the mandrel  108 ), a double-ended construction is also contemplated. In particular, a construction that is similar to the one just described with respect to one end of the wire guide  100  may be provided at both ends of the wire guide  100  such that a proximal end  114  of the mandrel  108  is also tapered and terminates before a proximal end  104  of the helically wound coil  102 . Additional safety wires may be provided that include contact surfaces flanking the tapered proximal end  114  of the mandrel  108 . In such a configuration, the mandrel  108  may only be attached to the helically wound coil  102  via the safety wires. Further, the double-ended construction may include preformed curves, such as the preformed curve  209  of the embodiment of  FIG. 2 , formed at each end of the wire guide. 
       INDUSTRIAL APPLICABILITY 
       [0034]    The present disclosure is generally applicable to wire guides for use in percutaneous endovascular procedures. More specifically, the present disclosure is applicable to wire guides having a mandrel positioned within a helically wound coil and terminating before a distal end of the helically wound coil. Further, the present disclosure finds application in procedures during which it is desirable to reduce mandrel protrusions. 
         [0035]    Referring generally to  FIGS. 1-5  and, more specifically, to the embodiment of  FIG. 2 , a wire guide  200  may include a helically wound coil  202  having a preformed curve  209 . A mandrel  208  is positioned within the helically wound coil  202  and terminates before the preformed curve  209 . First and second safety wires  218  and  220  are positioned within the helically wound coil  202  and have proximal ends  222  and  224  attached to the mandrel  208  and distal ends  226  and  228  attached to the distal end  206  of the helically wound coil  202 , such as at a first weldment  230 . The first and second safety wires  218  and  220  are positioned on opposite sides  232  and  234  of a distal tip  236  of the mandrel  208 , and have contact surfaces  238  and  240  facing the distal tip  236  of the mandrel  208  that have a shape other than convex. Specifically, for example, the shapes may be substantially flat, as shown in  FIG. 3 , or substantially concave, as shown in  FIGS. 4 and 5 . 
         [0036]    The first and second safety wires  218  and  220 , having the relative shapes and positioning described herein, are provided to reduce mandrel protrusion during endovascular procedures. Specifically, while advancing the wire guide  200  through blood vessels or arteries of a patient or, more particularly, while the distal end  206  of the helically wound coil  202  is manipulating sharp curves, the distal tip  236  of the mandrel  208  will tend to contact the contact surfaces  238  and  240  rather than strike through the helically wound coil  202 . Further by utilizing two safety wires  218  and  220  that are both welded to the distal end  206  of the helically wound coil  202  at distal ends  226  and  228  thereof, testing has indicated that the tensile strength of the weld joint, or first weldment  230 , is significantly increased. These benefits, as should be appreciated, will also be recognized in embodiments that do not include the preformed curve  209 . 
         [0037]    It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.