Patent Publication Number: US-2020276413-A1

Title: Catheter

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of International Application No. PCT/JP2018/002180 filed Jan. 25, 2018. The entire content of the priority application is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a medical device, and specifically to a catheter used by inserting into a lumen of a blood vessel or the like of a patient. 
     BACKGROUND ART 
     A catheter used by inserting into a lumen of a blood vessel or the like of a patient is known. A physician performing a procedure inserts a guidewire into the lumen of the catheter, protrudes a distal end of the guidewire from a distal end of the catheter, leads the catheter to a lesion using the guide wire, and places a device such as a stent or an embolic coil in the lesion through the lumen of the catheter. 
     A distal portion of the catheter used in the procedure is generally configured to be soft in order to improve a tracking performance to the guide wire, or to reduce a risk of perforating the lumen of the blood vessel or the like. For example, in Patent Document 1, a catheter tube is described in which the flexural modulus of the distal end is lowered, and the flexural modulus of the proximal end is raised (see  FIG. 2 , etc.).
     Patent Document 1: Japanese Patent Application Publication No. H08(1996)-57035 A   

     SUMMARY 
     However, recently there is often the procedure for severe patients having CTO (Chronic Total Occlusion) or a lesion close to CTO, and the conventional catheter described above cannot be inserted into such lesions smoothly. 
     The present disclosure has been made in response to forgoing problems of the conventional technique, and is intended to provide a catheter capable of preventing collapse of the catheter tip even when inserted into a stenosis such as CTO or the like, and being inserted easily into the stenosis. 
     Solution for Problems 
     It is characterized in that, to solve the foregoing problems, a catheter according to a first aspect of the present disclosure comprises a main body and a distal portion joined to a distal end of the main body, and made of a resin including metal or metal compound, wherein the distal portion includes a distal region and a proximal region disposed in a proximal side of the distal region, and a hardness of the distal region is higher than a hardness of the proximal region. 
     A second aspect of the present disclosure is characterized in that, in the catheter according to the first aspect, a surface roughness of the distal region is greater than a surface roughness of the proximal region. 
     A third aspect of the present disclosure is characterized in that, in the catheter according to the first aspect or the second aspect, a degree of exposure of the metal or metal compound on the surface of the distal region is higher than a degree of exposure of metal or metal compound on the surface of the proximal region. 
     Furthermore, a fourth aspect of the present disclosure is characterized in that, in the catheter according to any one of the first aspect to the third aspect, the metal or metal compound includes radiopaque metal. 
     Advantageous Effects 
     According to the first aspect of the present disclosure, as the catheter comprises a main body, and a distal portion joined to a distal end of the main body and made of a resin including metal or metal compound, wherein the distal portion includes a distal region and a proximal region disposed in a proximal side of the distal region, and a hardness of the distal region is higher than a hardness of the proximal region, the proximal region has a followability to a medical device such as a guidewire used together, and the catheter has an effect of improving insertability into the stenosis and an effect of preventing the collapse of the distal portion of the catheter when the catheter is inserted into the stenosis. 
     According to the second aspect of the present disclosure, as a surface roughness of the distal region is greater than a surface roughness of the proximal region in the catheter of the first aspect of the present disclosure, in addition to the effects of the catheter of the first aspect of the present disclosure, it is capable of further improving insertability into the stenosis to reduce the contact resistance between the hard distal region and the stenosis. 
     According to the third aspect of the present disclosure, as a degree of exposure of the metal or metal compound on the surface of the distal region is higher than a degree of exposure of the metal or metal compound on the surface of the proximal region in the catheter of the first aspect or the second aspect of the present disclosure, in addition to the effects of the catheter of the first aspect or the second aspect of the present disclosure, it is capable of improving insertability into the stenosis to reduce the contact resistance between the distal region and the stenosis by utilizing the metal or metal compound contained. 
     Further, according to the fourth aspect of the present disclosure, as metal or metal compound includes radiopaque metal in the catheter of any one of the first aspect to the third aspect of the present disclosure, in addition to the effects of the catheter of any one of the first aspect to the third aspect of the present disclosure, it is capable of improving a visibility of the distal portion by adding a performance of a visibility. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an overall view of the catheter of a first embodiment of the present disclosure. 
         FIG. 2  is a longitudinal sectional view around a distal portion of the catheter of the first embodiment. 
         FIG. 3  is a longitudinal sectional view around a distal portion of the catheter of the second embodiment. 
         FIG. 4  is a longitudinal sectional view around a distal portion of the catheter of the third embodiment. 
         FIG. 5  is a longitudinal sectional view around a distal portion of the catheter of the fourth embodiment. 
         FIG. 6  is a longitudinal sectional view around a distal portion of the catheter of the fifth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. 
     First Embodiment 
     First of all, a first embodiment of the present disclosure will be described. The drawings used in the present embodiment are provided to facilitate understanding of the present disclosure, and the dimensions of the drawings may differ from actual dimensions. 
       FIG. 1  is an overall view of the catheter of a first embodiment of the present disclosure, and  FIG. 2  is a longitudinal sectional view around a distal portion of the catheter of the first embodiment. 
     As shown in  FIG. 1 , a catheter  1  of the present embodiment includes a catheter body  5  (corresponding to “a main body” of the present disclosure), a distal tip  3  (corresponding to “a distal portion” of the present disclosure) joined to a distal end of the catheter body  5 , and a connector  8  joined to a proximal end of the catheter body  5 . 
     The catheter body  5  includes an inner layer  6   a , a braid  6   b  wound around an outer periphery of the inner layer  6   a , and an outer layer  6   c  covering the inner layer  6   a  and the braid  6   b  as shown in  FIG. 2 . 
     The inner layer  6   a  is an elongated hollow tubular body made of, for example, a resin and forms a lumen  4   b  for inserting a guidewire or other medical devices inside. Resin material forming the inner layer  6   a  is not particularly limited, and PTFE (polytetrafluoroethylene) may be used in the present embodiment. 
     The braid  6   b  is formed by weaving a total of 24 element wires of twelve first wires and twelve second wires (12×12) into a mesh alternately. The material constituting the braid  6   b  is also not particularly limited, and a stainless alloy, for example, may be used in the present embodiment. 
     The outer layer  6   c  is made of, for example, resin and covers the inner layer  6   a  and the braid  6   b . Resin material forming the outer layer  6   c  is not particularly limited, and, for example, polyamide, polyamide elastomer, polyester, polyurethane and the like may be used, with polyamide being used in the present embodiment. 
     The distal tip  3  is joined to the distal end of the catheter body  5  and has a tubular shape with a lumen  4   a  communicating with the lumen  4   b  of the catheter body  5 , and the distal tip  3  has a tapered periphery gradually decreasing in diameter toward the distal end from the catheter body  5 . 
     Further, the distal tip  3  includes a distal region  7  located on a distal side of the distal tip  3  and a proximal region  9  located on a proximal side of the distal region  7 . 
     Resin material forming the distal tip  3  is also not particularly limited, and polyurethane elastomer may be used in the present embodiment. 
     Powder made of, for example, biocompatible metal or metal compound may be mixed inside the distal tip  3 , with tungsten powder  2  being mixed inside the distal tip  3  in the present embodiment. 
     Incidentally, the material mixed inside the distal tip  3  is not limited to tungsten powder, and it may be powder made of, for example, radiopaque metal or radiopaque metal compound such as gold, platinum, iridium, platinum-iridium alloys, barium, barium sulfate, bismuth, bismuth compounds (bismuth oxide, bismuth trioxide, bismuth subcarbonate, bismuth subcarbonate, tungsten bismuth), zirconium oxide, tantalum, cobalt chrome alloys, tungsten, tungsten-based compound (tungsten oxide, tungsten dioxide, tungsten trioxide), stainless steel, or titanium. It may also be powder made of radiolucent metal or radiolucent metal compound. 
     However, if the powder consisting of radiopaque metal is mixed inside the distal tip  3 , visibility of the distal tip  3  under X-ray fluoroscopy can be enhanced. 
     This point is similar with respect to a powder of biocompatible metal or metal compound mixed inside the distal tip  3  in embodiments described below. 
     In the present embodiment, tungsten powder  2  is mixed only in the distal region  7 , not mixed in the proximal region  9 . Thus, in the present embodiment, the hardness of the distal region  7  is set higher than the hardness of the proximal region  9 . In addition, an outer surface  7   a  of the distal region  7  and an outer surface  9   a  of the proximal region  9  are smooth in the present embodiment. 
     The connector  8  is also made of resin, has a lumen communicating with the lumen  4   b  of the catheter body  5 , and is joined to the proximal end of the catheter body  5 . 
     According to the catheter  1  of the present embodiment, as the catheter  1  comprises a catheter body  5 , and a distal tip  3  joined to a distal end of the catheter body  5  and made of a resin including tungsten powder  2 , wherein the distal tip  3  includes a distal region  7  and a proximal region  9  disposed in a proximal side of the distal region  7 , and a hardness of the distal region  7  is higher than a hardness of the proximal region  9 , the proximal region  9  has a followability to a medical device such as a guidewire and the like used together, thus, the catheter  1  has an effect of improving insertability into the stenosis and an effect of preventing the collapse of the distal tip  3  of the catheter  1  when the catheter  1  is inserted into the stenosis. 
     Second Embodiment 
     Next, a second embodiment of the present disclosure will be described. The drawings used in the present embodiment are provided to facilitate understanding of the present disclosure, and the dimensions of the drawings may differ from actual dimensions. 
     Hereinafter the second embodiment of the present disclosure will be described, and the overall view of the catheter will not be described because it is similar to  FIG. 1 . Portions common to the first embodiment will be denoted by the same reference numerals, and descriptions of the portions will be omitted. 
     The catheter  11  of the second embodiment differs from the catheter  1  of the first embodiment in a distal tip configuration. That is, in the distal tip  3  of the catheter  1  of the first embodiment, powder of biocompatible metal or metal compound was mixed only in the distal region  7 , not mixed in the proximal region  9 . 
     In contrast, in the distal tip of the present embodiment, powder of biocompatible metal or metal compound is mixed in the distal region and the proximal region of the distal tip. 
       FIG. 3  is a longitudinal sectional view around a distal portion of the catheter of the second embodiment. 
     A catheter  11  of the present embodiment includes a catheter body  5  (corresponding to “a main body” of the present disclosure), a distal tip  3  (corresponding to “a distal portion” of the present disclosure) joined to a distal end of the catheter body  5 , and a connector  8  joined to a proximal end of the catheter body  5 . 
     The distal tip  13  is joined to the distal end of the catheter body  5  and has a tubular shape with a lumen  14   a  communicating with the lumen  4   b  of the catheter body  5 , and the distal tip  13  has a tapered periphery gradually decreasing in diameter toward the distal end from the catheter body  5 . 
     Further, the distal tip  13  includes a distal region  17  located on a distal side of the distal tip  13  and a proximal region  19  located on a proximal side of the distal region  17 . 
     Resin material forming the distal tip  13  is not particularly limited, and polyurethane elastomer may be used in the present embodiment. 
     Powder made of, for example, biocompatible metal or metal compound may be mixed inside the distal tip  13 , with tungsten powder  12  being mixed inside the distal tip  13  in the present embodiment. 
     In the present embodiment, tungsten powder  12  is mixed in the distal region  17  and the proximal region  19 . The amount per unit volume of tungsten powder  12  in the distal region  17  is greater than the amount per unit volume of the tungsten powder  12  in the proximal region  19 . 
     Thus, in the present embodiment, the hardness of the distal region  17  is set higher than the hardness of the proximal region  19 . In addition, an outer surface  17   a  of the distal region  17  and an outer surface  19   a  of the proximal region  19  are smooth in the present embodiment. 
     According to the catheter  11  of the present embodiment, as the catheter  11  comprises a catheter body  5 , and a distal tip  13  joined to a distal end of the catheter body  5  and made of a resin including tungsten powder  12 , wherein the distal tip  13  includes a distal region  17  and a proximal region  19  disposed in a proximal side of the distal region  17 , and a hardness of the distal region  17  is higher than a hardness of the proximal region  19 , the proximal region  19  has a followability to a medical device such as a guidewire and the like used together, thus, the catheter  1  has an effect of improving insertability into the stenosis and an effect of preventing the collapse of the distal tip  13  of the catheter  11  when the catheter  11  is inserted into the stenosis. 
     Third Embodiment 
     Next, a third embodiment of the present disclosure will be described. The drawings used in the present embodiment are provided to facilitate understanding of the present disclosure, and the dimensions of the drawings may differ from actual dimensions. 
     Hereinafter the third embodiment of the present disclosure will be described, and the overall view of the catheter will not be described because it is similar to  FIG. 1 . Portions common to the first embodiment will be denoted by the same reference numerals, and descriptions of the portions will be omitted. 
     The catheter  21  of the third embodiment differs from the catheter  11  of the second embodiment in condition of an outer surface of the distal tip of the catheter. That is, an outer surface  17   a  and an outer surface  19   a  of the distal tip  13  of catheter  11  of the second embodiment are smooth. In contrast, an outer surface of the distal tip of the present embodiment is irregular. 
       FIG. 4  is a longitudinal sectional view around a distal portion of the catheter of the third embodiment. 
     A catheter  21  of the present embodiment includes a catheter body  5  (corresponding to “a main body” of the present disclosure), a distal tip  23  (corresponding to “a distal portion” of the present disclosure) joined to a distal end of the catheter body  5 , and a connector  8  joined to a proximal end of the catheter body  5 . 
     The distal tip  23  is joined to the distal end of the catheter body  5  and has a tubular shape with a lumen  24   a  communicating with the lumen  4   b  of the catheter body  5 , and the distal tip  23  has a tapered periphery gradually decreasing in diameter toward the distal end from the catheter body  5 . 
     Further, the distal tip  23  includes a distal region  27  located on a distal side of the distal tip  23  and a proximal region  29  located on a proximal side of the distal region  27 . 
     Resin material forming the distal tip  23  is not particularly limited, and polyurethane elastomer may be used in the present embodiment. 
     Powder made of, for example, biocompatible metal or metal compound may be mixed inside the distal tip  23 , with tungsten powder  22  being mixed inside the distal tip  23  in the present embodiment. 
     In the present embodiment, tungsten powder  22  is mixed in the distal region  27  and the proximal region  29 . The amount per unit volume of tungsten powder  22  in the distal region  27  is greater than the amount per unit volume of the tungsten powder  22  in the proximal region  29 . Thus, in the present embodiment, the hardness of the distal region  27  is set higher than the hardness of the proximal region  29 . 
     Further, in the present embodiment, a surface roughness of an outer surface  27   a  of the distal region  27  is greater than a surface roughness of the outer surface  29   a  of the proximal region  29 . Incidentally, it is possible by known techniques such as sandblasting to control the surface roughness of the distal tip  23 . 
     According to the catheter  21  of the present embodiment, as the catheter  21  comprises a catheter body  5 , and a distal tip  23  joined to a distal end of the catheter body  5  and made of a resin including tungsten powder  22 , wherein the distal tip  23  includes a distal region  27  and a proximal region  29  disposed in a proximal side of the distal region  27 , a hardness of the distal region  27  is higher than a hardness of the proximal region  29 , and the surface roughness of the outer surface  27   a  of the distal region  27  is greater than the surface roughness of the outer surface  29   a  of proximal region  29 , in addition to the effects of the catheter  1  of the first embodiment and the catheter  11  of the second embodiment, it is capable of further improving insertability into the stenosis to reduce the contact resistance between the distal region  27  having high-hardness and the stenosis. 
     Fourth Embodiment 
     Next, a fourth embodiment of the present disclosure will be described. The drawings used in the present embodiment are provided to facilitate understanding of the present disclosure, and the dimensions of the drawings may differ from actual dimensions. 
     Hereinafter the fourth embodiment of the present disclosure will be described, and the overall view of the catheter will not be described because it is similar to  FIG. 1 . Portions common to the first embodiment will be denoted by the same reference numerals, and descriptions of the portions will be omitted. 
     The catheter  31  of the fourth embodiment differs from the catheter  21  of the third embodiment in structure of an outer surface of the distal tip of the catheter. That is, an outer surface  27   a  and an outer surface  29   a  of the distal tip  23  of catheter  21  of the third embodiment were configured to form an irregular state by resin constituting the distal tip  23 . In contrast, an outer surface of the distal tip of the present embodiment is configured to form an irregular state by powder of biocompatible metal or metal compound mixed inside the distal tip  23 . 
       FIG. 5  is a longitudinal sectional view around a distal portion of the catheter of the fourth embodiment. 
     A catheter  31  of the present embodiment includes a catheter body  5  (corresponding to “a main body” of the present disclosure), a distal tip  33  (corresponding to “a distal portion” of the present disclosure) joined to a distal end of the catheter body  5 , and a connector  8  joined to a proximal end of the catheter body  5 . 
     The distal tip  33  is joined to the distal end of the catheter body  5  and has a tubular shape with a lumen  34   a  communicating with the lumen  4   b  of the catheter body  5 , and the distal tip  33  has a tapered periphery gradually decreasing diameter toward the distal end from the catheter body  5 . 
     Further, the distal tip  33  includes a distal region  37  located on a distal side of the distal tip  33  and a proximal region  39  located on a proximal side of the distal region  37 . 
     Resin material forming the distal tip  33  is not particularly limited, and polyurethane elastomer may be used in the present embodiment. 
     Powder made of, for example, biocompatible metal or metal compound is mixed inside the distal tip  33 , with tungsten powder  32  being mixed inside the distal tip  33  in the present embodiment. 
     In the present embodiment, tungsten powder  32  is mixed in the distal region  37  and the proximal region  39 . The amount per unit volume of tungsten powder  32  in the distal region  37  is greater than the amount per unit volume of the tungsten powder  32  in the proximal region  39 . Thus, in the present embodiment, the hardness of the distal region  37  is set higher than the hardness of the proximal region  39 . 
     Further, in the present embodiment, a surface roughness of an outer surface  37   a  of the distal region  37  is greater than a surface roughness of the outer surface  39   a  of the proximal region  39 . 
     A convex portion in the irregular state defining a surface roughness is formed by protrusion of tungsten  32  mixed inside the distal region  37  and the proximal region  39  from the outer surface  37   a  of the distal region  37  and the outer surface  39   a  of the proximal region  39  (a tungsten  32  protruding from the outer surface  39   a  is written as a projecting tungsten  32   a  in  FIG. 5 ) in the present embodiment. 
     In the present embodiment, as the amount per unit volume of tungsten powder  32  in the distal region  37  is larger than the amount per unit volume of tungsten powder  32  in the proximal region  39 , the number per unit area of the projecting tungsten  32   a  on the outer surface  37   a  of the distal region  37  can be easily increased more than the number per unit area of the projecting tungsten  32   a  on the outer surface  39   a  of the proximal region  39  to remove resin constituting the distal tip  33  by means of simply melting, evaporating or the like. 
     In this case, a degree of exposure of the tungsten  32   a  on the outer surface  37   a  of the distal region  37  is higher than a degree of exposure of the tungsten  32   a  on the outer surface  39   a  of the proximal region  39 . 
     According to the catheter  31  of the present embodiment, as the catheter  31  comprises a catheter body  5 , and a distal tip  33  joined to a distal end of the catheter body  5  and made of a resin including tungsten powder  32 , wherein the distal tip  33  includes a distal region  37  and a proximal region  39  disposed in a proximal side of the distal region  37 , a hardness of the distal region  37  is higher than a hardness of the proximal region  39 , and degree of exposure of tungsten  32   a  on the outer surface  37   a  of the distal region  37  is higher than degree of exposure of tungsten  32   a  on the outer surface  39   a  of the proximal region  39 , in addition to the effects of the catheter  21  of the third embodiment, it is capable of further improving insertability into the stenosis to reduce the contact resistance between the distal region  37  having high-hardness and the stenosis easily. 
     Fifth Embodiment 
     Next, a fifth embodiment of the present disclosure will be described. The drawings used in the present embodiment are provided to facilitate understanding of the present disclosure, and the dimensions of the drawings may differ from actual dimensions. 
     Hereinafter the fifth embodiment of the present disclosure will be described, and the overall view of the catheter will not be described because it is similar to  FIG. 1 . Portions common to the first embodiment will be denoted by the same reference numerals, and descriptions of the portions will be omitted. 
     The catheter  41  of the fifth embodiment differs from the catheter  31  of the fourth embodiment in structure of a distal region of the distal tip of the catheter. That is, a distal region  32  of the distal tip  33  of the catheter  31  of the fourth embodiment is constituted by resin in normal state except tungsten  32 . In contrast, a distal region of the distal tip of the present embodiment is constituted by evaporating a certain amount of resin from resin constituting the distal region  37 . 
       FIG. 6  is a longitudinal sectional view around a distal portion of the catheter of the fifth embodiment. 
     A catheter  41  of the present embodiment includes a catheter body  5  (corresponding to “a main body” of the present disclosure), a distal tip  43  (corresponding to “a distal portion” of the present disclosure) joined to a distal end of the catheter body  5 , and a connector  8  joined to a proximal end of the catheter body  5 . 
     The distal tip  43  is joined to the distal end of the catheter body  5  and has a tubular shape with a lumen  44   a  communicating with the lumen  4   b  of the catheter body  5 , and the distal tip  43  has a tapered periphery gradually decreasing diameter toward the distal end from the catheter body  5 . 
     Further, the distal tip  43  includes a distal region  47  located on a distal side of the distal tip  43  and a proximal region  49  located on a proximal side of the distal region  47 . 
     Resin material forming the distal tip  43  is not particularly limited, and polyurethane elastomer may be used in the present embodiment. 
     Powder made of, for example, biocompatible metal or metal compound may be mixed inside the distal tip  43 , with tungsten powder  42  being mixed inside the distal tip  43  in the present embodiment. 
     In the present embodiment, tungsten powder  42  is mixed in the distal region  47  and the proximal region  49 . The amount per unit volume of tungsten powder  42  in the distal region  47  is substantially equal to the amount per unit volume of the tungsten powder  42  in the proximal region  49 . 
     On the other hand, in the distal region  47  of the distal tip  43  of the present embodiment, a certain amount of resin is evaporated from the outer surface  47   a  of the distal region  47  by laser irradiation such as with an excimer laser etc. Thus, the hardness of the distal region  47  is set higher than the hardness of the proximal region  49  in the present embodiment. 
     Further, in the present embodiment, a surface roughness of an outer surface  47   a  of the distal region  47  is greater than a surface roughness of the outer surface  49   a  of the proximal region  49 . This is set by controlling irradiation time and the like of the excimer laser, etc., so that the evaporation amount of the resin in the distal region  47  is more than the evaporation amount of the resin in the proximal region  49 . 
     In the present embodiment, as in the fourth embodiment, a convex portion in the irregular state defining a surface roughness is formed by protrusion of tungsten  42  mixed inside the distal region  47  and the proximal region  49  from the outer surface  47   a  of the distal region  47  and the outer surface  49   a  of the proximal region  49  (a tungsten  42  protruding from the outer surface  39   a  is written as a projecting tungsten  42   a  in  FIG. 6 ). 
     That is, in the present embodiment, the protrusion height of the projection tungsten  42   a  on the outer surface  47   a  of the distal region  47  is higher than the protrusion height of the projection tungsten  42   a  on the outer surface  49   a  of the proximal region  49 . Thus, the surface roughness of the outer surface becomes great. 
     According to the catheter  41  of the present embodiment, as the catheter  41  comprises a catheter body  5 , and a distal tip  43  joined to a distal end of the catheter body  5  and made of a resin including tungsten powder  42 , wherein the distal tip  43  includes a distal region  47  and a proximal region  49  disposed in a proximal side of the distal region  47 , a hardness of the distal region  47  is higher than a hardness of the proximal region  49  by evaporating a certain amount of resin from the distal region  47 , and a surface roughness of the outer surface  47   a  of the distal region  47  is greater than a surface roughness of the outer surface  49   a  of the proximal region  49  by control the height of the projection tungsten  42   a  that tungsten  42  mixed inside the distal tip  43  protrudes from the outer surface of the distal tip  43 , in addition to the effects of the catheter  31  of the fourth embodiment, the catheter  41  can be easily set a hardness difference between the distal region  47  and the proximal region  49 . The proximal region  49  also has a followability to a medical device such as a guidewire and the like used together, thus, the catheter  41  has an effect of improving insertability into the stenosis and an effect of preventing the collapse of the distal tip  43  of the catheter  41  when the catheter  41  is inserted into the stenosis. 
     The catheter  41  includes the distal region  47  characterized in that it is formed by evaporating the resin of a distal portion more than the proximal region  49 . According to this catheter  41 , as the distal region  47  is formed by evaporating the resin of the distal portion more than the proximal region  49 , a manufacturer can easily set a hardness of the distal region  47  and a hardness of the proximal region  49  by only adjusting energy of the laser, etc., and can easily set a surface roughness of the distal region  47  and a surface roughness of the proximal region  49  by only adjusting energy of the laser, etc. 
     While catheters of the various embodiments of the present disclosure have been described in each of the foregoing embodiments as an example of catheters, such catheters are not limited to the foregoing embodiments. Any catheter can be implemented with various modifications within a scope not departing from a subject matter thereof. 
     For example, a hardness difference between the distal region and the proximal region in the first to fourth embodiments is caused on the basis of the amount of biocompatible metal or metal compound exemplified by tungsten mixed inside the distal region and the proximal region. However, as shown in the fifth embodiment, it is possible to set higher a hardness of the distal region than a hardness of the proximal region by evaporating a certain amount of resin from the distal region in the first to fourth embodiments. 
     Catheters in the first to fifth embodiments have been described as the distal tip  3 ,  13 ,  23 ,  33  and  43  as being applied to a catheter of the simplest configuration. However, they are not limited thereto. The distal tip  3 ,  13 ,  23 ,  33  and  43  are applicable to any medical catheter such as a balloon catheter and a multi-lumen catheter. 
     DESCRIPTION OF THE CODE 
     
         
           1 ,  11 ,  21 ,  31 ,  41  . . . catheter 
           2 ,  12 ,  22 ,  32 ,  42  . . . tungsten (Examples of biocompatible metal or metal compound) 
           3 ,  13 ,  23 ,  33 ,  43  . . . distal tip 
           7 ,  17 ,  27 ,  37 ,  47  . . . distal region 
           9 ,  19 ,  29 ,  39 ,  49  . . . proximal region 
           5  . . . catheter body 
           8  . . . connector 
           6   a  . . . inner layer 
           6   b  . . . braid 
           6   c  . . . outer layer