JP4910566B2 - Stent delivery catheter - Google Patents

Description

  The present invention relates to a stent delivery catheter used for indwelling a stent in a body, and more specifically, a phenomenon in which an inner tube and an outer tube are in close contact with each other, and an inner tube when the inner tube is removed from an open stent. The present invention relates to a stent delivery catheter in which the phenomenon that the stent is caught at the same time is prevented at the same time, and as a result, the stent can be easily placed at the intended position.

  For example, in order to ensure the patency of the digestive tract narrowed by cancer cells and the blood vessels narrowed due to arteriosclerosis, a medical method in which a stent is placed at the stenotic site is known. Stents are roughly classified into self-expandable stents and balloon-expandable stents. When a self-expandable stent is placed in the body, for example, a stent as described in Patent Document 1 It is known to use a delivery catheter.

  The stent delivery catheter (device) described in Patent Document 1 is composed of two tubes arranged concentrically, and a self-expanding stent is arranged between an inner tube and an outer tube At the site where the stent is to be placed, the stent is released by pulling the outer tube toward the outside of the body and placed in the body.

  However, in the stent delivery catheter described in Patent Document 1, since there is a step near the distal end of the inner tube (inner catheter), when the inner tube is pulled out of the opened stent, the stent is placed at the step of the inner tube. In some cases, the stent may be detained and the indwelling position of the stent may be shifted, or the inner tube may not be pulled out.

In order to solve this problem, a stent delivery catheter (a device for treating a stenosis in a body cavity) as described in Patent Document 2 has been proposed. In the stent delivery catheter described in Patent Document 2, in order to eliminate the step of the inner tube that causes the stent to be caught, the vicinity of the distal end of the stent accommodating small-diameter portion gradually increases in diameter toward the distal end side. It is formed in the part.
JP 2004-223262 A Japanese Patent Laid-Open No. 9-84880

  However, even when the stent delivery catheter described in Patent Document 2 is used, the placement position of the stent sometimes deviates from the intended position. When the present inventors examined the cause, in the stent delivery catheter as described in Patent Document 2, the outer tube is positioned so as to cover the stent disposed on the inner tube. As a result, it became clear that the inner tube taper portion was fitted into the edge of the distal end opening of the outer tube, and as a result, the inner tube and the outer tube were in close contact with each other. And since the inner tube and the outer tube are in close contact with each other like this, it is necessary to release the contact with a strong force when pulling the outer tube to the proximal end side in order to open the stent. In this case, a strong recoil is generated, and it has become clear that the indwelling position of the stent is shifted by the recoil.

  Therefore, in view of the above situation, the present invention can simultaneously prevent the phenomenon in which the inner tube and the outer tube are in close contact with each other and the phenomenon in which the stent is caught on the inner tube when the inner tube is removed from the opened stent. As a result, an object of the present invention is to provide a stent delivery catheter in which a stent can be easily placed at an intended position.

  The present inventors have examined a stent delivery catheter as described in Patent Document 2 in order to avoid a phenomenon in which the inner tube and the outer tube are strongly adhered to each other. Based on this finding, the inventors have found that a groove extending in the direction may be provided.

That is, the stent delivery catheter of the present invention includes an outer tube having a distal end and a proximal end, and an inner tube inserted into the outer tube, and the outer tube and the inner tube are arranged along the axial direction. The inner tube includes a cylindrical inner tube body, and a protrusion provided on the distal end side of the inner tube body and projecting from the distal end of the outer tube, The inner tube main body includes a cylindrical main body portion, and a small diameter portion provided on a distal end side of the main body portion and having a diameter smaller than that of the main body portion for disposing the stent, The projecting portion is provided so as to be continuous with the small-diameter portion, and has a tapered portion formed with a taper that increases in diameter toward the distal end side, and a distal end portion on the distal end side of the tapered portion. A groove extending in a direction along the axial direction of the inner tube is formed on the tapered surface of the tapered portion. Are, the groove in the protruding portion is only provided on the tapered portion, and is characterized in that it is formed such that the width toward the proximal end is wider at the tapered portion.

In this embodiment, the grooves are preferably continuously extends to the proximal end from the distal end of the front Symbol tapered portion.

  In addition, it is preferable that there are a plurality of the grooves, and in this case, it is preferable that the plurality of grooves are provided at equal intervals in the circumferential direction around the axis of the inner tube main body. Moreover, it is preferable that all the plurality of grooves have the same shape.

  Moreover, the said inner pipe main body and the said protrusion part may be integral, and are good also as another body.

  In the stent delivery catheter of the present invention, since the tapered portion connected to the small diameter portion is provided, the inner tube is prevented from being caught on the stent when the catheter is removed from the body. Further, since the groove is provided in the tapered portion, the contact area between the tapered portion and the edge of the distal end opening of the outer tube covering the surface of the tapered portion is reduced, and the adhesion force between the inner tube and the outer tube is reduced. As a result, resistance to pulling out the outer tube is reduced, so that the stent can be placed smoothly. That is, according to the present invention, the phenomenon in which the inner tube and the outer tube are strongly adhered to each other and the phenomenon that the stent is caught on the inner tube when the inner tube is pulled out from the opened stent are simultaneously prevented. A stent delivery catheter is provided that can easily place the stent in the intended location.

  Hereinafter, in order to facilitate understanding of the present invention, an embodiment of the present invention will be described with reference numerals attached to the accompanying drawings. However, the present invention is not limited to the illustrated embodiment.

  FIG. 1A and FIG. 1B are side views showing the entirety of a stent delivery catheter 100 (hereinafter also simply referred to as catheter 100), which is an embodiment of the present invention. FIG. 1A is a view showing a state of the catheter 100 before the stent placement operation, and FIG. 1B shows that the outer tube 20 is moved to the proximal end side by operation after the catheter 100 is inserted into the body. The state where the stent 40 is exposed is shown.

  As shown in FIGS. 1 (a) and 1 (b), the catheter 100 has an inner tube 10 and an outer tube 20 having a distal end and a proximal end, respectively. The inner tube 10 is inserted into the outer tube 20, and the outer tube 20 and the inner tube 10 are configured to be relatively movable along the axial direction. Contrast markers 15 and 25 are attached near the distal ends of the inner tube 10 and the outer tube 20, respectively. The inner tube 10 is a cylindrical inner tube body 11 and a portion that is provided on the distal end side of the inner tube body 11 and protrudes from the distal end of the outer tube 20 when in the state of FIG. It is comprised from the protrusion part 30. FIG.

  As shown in FIG. 1B, the inner tube main body 11 is provided on the distal end side of the cylindrical main body portion 10b and the main body portion 10b. The inner tube main body 11 is narrower than the main body portion 10b in order to arrange the stent 40. And a small-diameter portion 10a formed in a diameter. The stent 40 is disposed so as to cover the outer peripheral surface of the small-diameter portion 10a, and the outer tube 20 is disposed so as to cover the outer peripheral side of the stent 40.

  The projecting portion 30 is provided so as to be continuous with the small-diameter portion 10a, and has a tapered portion 32 formed with a taper that increases in diameter toward the distal end side, and is positioned on the distal end side of the tapered portion 32. And a distal end portion 31. In the state before the stent placement operation, the tapered portion 32 of the protruding portion 30 is covered with the edge of the distal end opening of the outer tube 20 as shown in FIG.

  The inner tube 10 and the outer tube 20 are connected to the slide guide pipe 60 and the connector 50 on the proximal end side, respectively. The inner tube 10 and the slide guide pipe 60 are slidably inserted into the lumens of the outer tube 20 and the connector 50, and when the connector 50 is pulled toward the proximal end side with respect to the slide guide pipe 60, The connected outer tube 20 moves relative to the inner tube 10 toward the proximal end side along the axial direction.

  When the catheter 100 is inserted into the patient's body, as shown in FIG. 1A, the outer tube 20 covers the entire surface of the stent 40 and covers the tapered portion 32 of the protruding portion 30 at the distal end opening. The expansion of the stent 40 in the radial direction is restricted.

  In FIG. 1B, in order to clarify the positional relationship between the stent 40 and the inner tube 10 and the outer tube 20, the stent 40 in an unexpanded state is shown, but the stent 40 is self-expanding. In the case of a type of stent, when the stent is released from the outer tube 20 as shown in the figure, it expands and is separated from the outer peripheral surface of the inner tube 10.

  2A is a side view of the protrusion 30 of the stent delivery catheter 100 of FIG. 1, and FIG. 2B is a plan view of the protrusion 30 viewed from the direction of arrow A in FIG. 2A. is there. As described above, the projecting portion 30 is formed in a tapered portion 32 that expands in diameter toward the distal end side, and a tapered shape that is located on the distal end side of the tapered portion and becomes thinner toward the distal end side. It has the tip part 31 formed. As shown in FIGS. 2A and 2B, the tapered surface of the tapered portion 32 of the present embodiment is along the axial direction of the inner tube with the boundary between the tip portion 31 and the tapered portion 32 as a vertex. Four grooves 33 extending in the proximal end side direction are formed at equal intervals in the circumferential direction, whereby the surface of the tapered portion 32 is cut out in an isosceles triangle shape in plan view. In the present embodiment, all of the grooves 33 have substantially the same shape.

  The tapered shape of the distal end portion 31 of the protruding portion 30 mainly serves to reduce insertion resistance and facilitate the insertion of the catheter 100 into the body. The tapered shape of the tapered portion 32 completes the stent placement operation. It has a role to prevent the protrusion 30 from being caught on the stent 40 when the catheter 100 is later removed from the body.

  By providing the protruding portion 30 with the tapered portion 32 and eliminating the step, it is possible to prevent the stent 40 from being caught. However, as a result, when the tapered portion 32 is covered with the edge of the distal end opening of the outer tube 20 (FIG. 1A), the surface of the tapered portion 32 is tightly covered by the outer tube 20. In addition, the contact area between the protrusion 30 and the outer tube 20 increases. The protruding portion 30 and the outer tube 20 are usually formed of a relatively elastic or adhesive material such as resin or elastomer, and the inner tube 10 and the outer tube 20 are strongly strengthened by increasing the contact area. It will be in close contact. As a result, when the outer tube 20 is moved to the proximal end side, a strong force is required to peel off the outer tube 20 from the projecting portion 30, and a strong reaction occurs when the contact is released. As a result, the indwelling position of the stent 40 is shifted. Therefore, in the stent delivery catheter 100 of the present invention, by providing the tapered portion 32 to prevent the stent 40 from being caught, the groove 33 is further provided in the tapered portion 32 to reduce the surface area of the tapered portion 32. The contact area between the tapered portion 32 and the outer tube 20 and hence the adhesion force is reduced, and the outer tube 20 is smoothly separated from the tapered portion 32 when the outer tube 20 is moved to the proximal end side of the stent placement operation. ing.

  The shape and number of the grooves 33 provided on the taper surface of the taper portion 32 are not limited. However, from the viewpoint of preventing the distal end opening of the outer tube 20 from being caught on the taper portion 32, the groove 33 is formed on the taper portion 32. Instead of being continuous in the circumferential direction, the individual grooves 33 are independently formed in a shape extending in the direction along the axial direction. Here, the shape extending in the direction along the axial direction is a shape in which the longitudinal center line in the side view of the groove 33 (broken line L in FIG. 2A) is parallel to the axial center of the catheter 100. Say. On the other hand, in plan view (see FIG. 2B), the grooves 33 are formed radially from the axial center of the catheter 100 toward the outer periphery. From the viewpoint of further reducing the resistance and smoothly moving the outer tube 20 toward the proximal end side, the shape of the groove 33 on the surface of the tapered portion 32 increases from the distal end side toward the proximal end side. It is preferable that the width is wide, and it is preferable that the taper portion 32 is continuously extended from the distal end to the proximal end. Furthermore, from the viewpoint of reducing the adhesion between the tapered portion 32 and the outer tube 20 without unevenness, a plurality of grooves 33 are provided at equal intervals in the circumferential direction centering on the axis of the inner tube body. These grooves are preferably all the same shape.

  As described above, the groove 33 mainly serves to reduce the surface area of the tapered portion 32 and reduce the contact area between the tapered portion 32 and the outer tube 20. As long as it has a simple shape, the three-dimensional shape of the groove 33 is not limited, and it can be cut into any shape such as a curved surface, a rectangular shape, or a prism.

  The total area of the grooves 33 on the surface of the tapered portion 32 is from the viewpoint of effectively reducing the frictional resistance while preventing the edge of the distal end opening of the outer tube 20 from coming off from the tapered portion 32 due to resistance at the time of insertion into the body. Is preferably 20 to 80%, where the surface area of the tapered portion 32 without the grooves 33 is 100%.

  In order to prevent the inner wall 10 from perforating the body wall, the protrusion 30 is preferably formed of a material having rubber elasticity, and a thermoplastic elastomer is particularly preferable. Among these, those having a Shore hardness of 25D to 72D are preferably used. In the illustrated form, the protrusion 30 is formed of a polyamide elastomer. In the present embodiment, the tip portion 31 and the tapered portion 32 are attached to the distal end of the inner tube 10 as a protruding portion 30 formed separately from the inner tube 10. The tapered portion 32 may be integrally formed on the distal end side of the inner tube 10 as a part of the inner tube 10. Moreover, between the front-end | tip part 31 and the taper part 32, the center part which is an area | region with a uniform thickness connected with these may be provided. The length of the distal end portion 31 is preferably 1 to 12 mm, and the length of the tapered portion 32 is preferably 1 to 5 mm. Moreover, it is preferable that the outer diameter of the part used as the largest diameter part of the protrusion part 30, ie, the outer diameter of the part which is a boundary of the front-end | tip part 31 and the taper part 32 in this embodiment, is 1-4 mm.

  In the present embodiment, the inner tube main body 11 has a two-layer structure including an inner tube inner layer and an inner tube outer layer formed so as to cover the inner tube inner layer on the proximal end side of the stent 40 attachment site. ing. The distal end of the inner tube inner layer is located on the distal end side with respect to the distal end of the inner tube outer layer, thereby forming a small-diameter portion 10 a for placing the stent 40. The step formed at the boundary between the small-diameter portion 10a and the distal end of the inner tube outer layer (that is, the main body portion 10b) is the proximal end side of the outer tube 20 which is an operation required when the stent 40 is placed at a predetermined position. It serves as a stopper to prevent the stent 40 from moving to the proximal end side together with the outer tube 20 during the movement operation.

  Although there is no restriction | limiting in particular as a material of the inner tube | pipe 10, It is desired to have flexibility and a synthetic resin is normally used. Since the inner tube 10 is required to have a certain degree of rigidity and slidability, the inner tube 10 is preferably formed of a material that does not substantially have rubber elasticity. In the present embodiment, the inner tube inner layer is a high-rigidity polyetheretherketone resin, and the inner tube outer layer is a high-density polyethylene excellent in slidability. In order to improve rigidity and slidability, the surface of the material may be coated. As for the dimension of the inner tube 10, the length is generally the sum of the lengths of the outer tube 20 and the connector 50, and is about 300 to 2000 mm. The outer diameter of the small-diameter portion 10a, that is, the outer diameter of the inner tube inner layer in the present embodiment is about 0.5 to 2.5 mm, depending on the size of the stent 40, etc. The diameter, that is, the outer diameter of the inner tube outer layer in this embodiment is about 1.5 to 3.0 mm.

  Although there is no restriction | limiting in particular as a material of the outer tube | pipe 20, Since it is desired to have flexibility, a synthetic resin and an elastomer are normally used. The outer tube 20 in the illustrated catheter 100 has a two-layer structure in which the inner layer is made of polytetrafluoroethylene, the outer layer is made of polyamide on the proximal end side, and the distal end side is made of polyamide elastomer, and a metal wire is interposed between the inner layer and the outer layer. A net-like reinforcement body made of is arranged. These materials may be reinforced with a metal wire or the like, or the surface may be coated. The outer tube 20 has an outer diameter slightly larger than the outer diameter of the inner tube 10, usually 1.0 to 4.0 mm, an inner diameter of 0.8 to 3.0 mm, and a length of about 300 to 2500 mm. .

  The contrast markers 15 and 25 attached to the vicinity of the distal ends of the inner tube 10 and the outer tube 20 shown in FIG. 1B are detected by X-ray fluoroscopy and serve as markers in the body. For example, it is formed of a metal material such as gold, platinum or tungsten, or a polymer blended with barium sulfate or bismuth oxide. When the contrast markers 15 and 25 are attached in the vicinity of the distal end of the inner tube 10 and / or the outer tube 20, the positions of the contrast markers 15 and 25 can be detected by X-ray fluoroscopy. This is preferable because the position can be accurately grasped. In particular, it is preferable to attach the contrast markers 15 and 25 to both the inner tube 10 and the outer tube 20 as shown in the figure, because it is possible to know whether or not the stent 40 has been released by grasping the relative positions of the respective tubes. The shape of the contrast markers 15 and 25 is not particularly limited, but is preferably a ring shape. The contrast markers 15 and 25 may be attached to the inner peripheral surface or the outer peripheral surface of the inner tube 10 and / or the outer tube 20, or may be embedded in the inner tube 10 and / or the outer tube 20.

  The slide guide pipe 60 to which the inner tube 10 is connected has a guide wire insertion lumen formed therein, and the distal end of the slide guide pipe 60 is connected to the proximal end of the inner tube 10. Thus, a continuous through hole is formed from the proximal end of the slide guide pipe 60 to the distal end of the inner tube 10, and a guide wire for guiding the catheter 100 from the outside of the body to the stent placement site can be inserted.

  A connector 50 to which the outer tube 20 is connected is attached to the outer periphery of the slide guide pipe 60 so as to be movable in the axial direction with respect to the slide guide pipe 60. By pulling the connector 50 toward the proximal end side with respect to the slide guide pipe 60, the outer tube 20 connected to the connector 50 also moves toward the proximal end side, and the stent 40 is gradually exposed from the distal end side. To go. When the outer tube 20 is finally completely detached from the stent 40, the stent 40 that is restrained by the outer tube 20 is released and expands.

  Although there is no restriction | limiting in particular as a material which comprises the connector 50 and the slide guide pipe 60, From a viewpoint of weight reduction, it may form with synthetic resins, such as a polycarbonate, polyamide, a polyarylate, a methacrylate-butylene-styrene copolymer. preferable.

  Although there is no restriction | limiting in particular in the stent 40 with which the stent delivery catheter 100 of this embodiment is mounted | worn, Usually, a self-expanding stent is used. The self-expanding stent is a stent that expands from its contracted state by its own elastic force, and is usually composed of a superelastic metal such as a nickel titanium alloy or a cobalt chromium alloy or a shape memory metal.

  The part of the body where the stent 40 is placed by the stent delivery catheter 100 of the present invention described above is not particularly limited. It can be used to place the stent 40 in any body lumen such as a tube, trachea or blood vessel. Among these, the stent delivery catheter 100 of the present invention is suitably used when the stent 40 is placed in the digestive tract via an endoscope. Furthermore, among them, when used when placing the stent 40 in a bile duct where there are many bends and branches and the placement operation of the stent 40 is difficult, the effect of the ease of placement operation of the catheter 100 of the present invention is maximized. Can be particularly effective.

<Modification>
FIG. 3A is a perspective view of a protrusion 130 according to another embodiment of the stent delivery catheter 100 of FIG. FIG. 3B is a plan view of the protrusion 130 viewed from the direction of arrow B in FIG. FIG.3 (c) is a side view of the protrusion part 130 of Fig.3 (a). FIG.3 (d) is a top view of the protrusion part 130 seen from the arrow C direction of Fig.3 (a).

  The projecting portion 130 has a tip portion 131 formed in a tapered shape that becomes thinner toward the distal end side, and a tapered portion 132 that is continuous with the tip portion 131 and expands toward the distal end side. Yes. As shown in FIGS. 3A and 3B, the tapered surface of the tapered portion 132 of the present embodiment is along the axial direction of the inner tube with the boundary between the tip portion 131 and the tapered portion 132 as an apex. Four grooves 133 extending in the proximal end direction are provided at equal intervals in the circumferential direction. The surface of the groove 133 is formed in a curved surface shape. At the boundary portion between the tip portion 131 and the taper portion 132, the groove 133 is formed so as not to have a step.

  The number of grooves is not limited. The interval between the grooves is not limited to an equal interval. Moreover, it is preferable that the ratio of a groove | channel is 20 to 80% by making the surface area of the taper part 132 in the state without the groove | channel 133 into 100%. 3A to 3D, the function of the protrusion 130 and the shape, nature, and material of each component are the same as those of the protrusion 30 except for the shape of the groove 133 of the protrusion 130. Since it is the same as the shape, property, material, and the like of each component, description thereof is omitted here.

It is a side view which shows the stent delivery catheter 100 which is one Embodiment of this invention. It is an enlarged view of the protrusion part 30 of the stent delivery catheter 100, (a) is a side view, (b) is the top view seen from the arrow A direction. It is a figure which shows the protrusion part 130 of another form, (a) is a perspective view, (b) is the top view seen from the arrow B direction, (c) is a side view, (d) is seen from the arrow C direction. It is a top view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inner pipe 10a Thin diameter part 10b Main body part 11 Inner pipe main body 20 Outer pipe 30, 130 Protruding part 31, 131 Tip part 32, 132 Tapered part 33, 133 Groove 40 Stent 50 Connector 60 Slide guide pipe 100 Stent delivery catheter

Claims (6)

A stent delivery catheter for placing a stent in a body lumen,
An outer tube having a distal end and a proximal end, and an inner tube inserted into the outer tube,
The outer tube and the inner tube are configured to be relatively movable along the axial direction,
The inner tube includes a cylindrical inner tube main body, and a protrusion provided on the distal end side of the inner tube main body and protruding from the distal end of the outer tube,
The inner tube main body includes a cylindrical main body portion, and a small diameter portion provided on a distal end side of the main body portion and formed to have a smaller diameter than the main body portion in order to dispose the stent.
The projecting portion is provided so as to be continuous with the small-diameter portion, and has a tapered portion formed with a taper that increases in diameter toward the distal end side, and a tip portion on the distal end side of the tapered portion, With
A groove extending in a direction along the axial direction of the inner tube is formed on the tapered surface of the tapered portion ,
The stent delivery catheter , wherein the groove is provided only in the tapered portion in the protruding portion, and is formed so that the width becomes wider toward the proximal end in the tapered portion . The stent delivery catheter according to claim 1 , wherein the groove continuously extends from a distal end to a proximal end of the tapered portion. The stent delivery catheter according to claim 1 or 2 , wherein the groove is plural. The stent delivery catheter according to claim 3 , wherein the plurality of grooves are provided at equal intervals in a circumferential direction centering on an axis of the inner tube main body. The stent delivery catheter according to claim 3 or 4 , wherein all of the plurality of grooves have the same shape. The stent delivery catheter according to any one of claims 1 to 5 , wherein the inner tube main body and the protruding portion are separate bodies.

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