JP2012065824A - Stent delivery catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent delivery catheter allowing stable operation without needing excessive force when operating a sheath for disposing a stent in a lesion part, having excellent operability to a curved passage, and allowing accurate disposal of the stent inside a target portion.SOLUTION: This stent delivery catheter includes a catheter body 101, and an inner catheter 105 which has at least a part inserted through a lumen 104 formed in the catheter body 101, and has a near end and a remote end. The inner catheter 105 has: a tubular member 201 having a guide wire lumen; a core wire 203 disposed outside the tubular member 201 or inside the wall face parallel thereto; a flexible covering member 204 disposed such that the covering member 204 covers the periphery of the tubular member 201 and the core wire 203; and a stopper 106 preventing that the stent 102 moves to the near side when moving the catheter body 101 to the near side relatively to the inner catheter 105.

Description

  The present invention generally relates to a stent delivery catheter for placing a tubular stent within a blood vessel.

  Stents are typically used to expand the stenosis or occlusion site to treat various diseases caused by stenosis or occlusion of blood vessels or other in vivo lumens, and to the lesion site to maintain the lumen size. Used as a medical device for indwelling. Stents consist of a coiled stent made of a single linear metal or polymer material, processed by cutting a metal tube with a laser, assembled by welding linear members with a laser, There are things made by weaving multiple linear metals. Generally, a stent is composed of a metal, a polymer, or a composite thereof, and is most commonly composed of a metal such as SUS316 steel, a Co—Cr alloy, or a Ni—Ti alloy.

  Stents are tubular structures that can be radially expanded to keep constricted blood vessels open. The expansion mechanism of the stent is roughly classified into a self-expandable stent that expands due to the shape memory property and superelasticity of the stent itself, and a balloon-expandable stent that is expanded by a balloon catheter. .

  Of these, the self-expanding stent is generally attached to the vicinity of the distal end of the intravascular catheter, and is used with a sheath or the like placed thereon, and the catheter is advanced to the treatment site in the body lumen of the patient. The sheath and the like are removed, and the stent is self-expanded along with this, and is used in a method of indwelling. In recent years, many of these stents have been used for ureteral, bile duct, and lower limb arterial surgery.

  After transporting to the lesion site with the stent delivery catheter, the operator pulls the sheath from the proximal side to place the stent in the catheter. At this time, the force pulling the sheath from the proximal side causes the sheath and the stent to be static at first. It is fixed to and has a great resistance to operate. Thereafter, the resistance dynamically decreases as the stent moves axially relative to the sheath.

  Due to the placement of the stent, the force required during operation must overcome the friction both between the stent and the sheath and between the endovascular catheter and the sheath. The tension acting on the outside of the sheath opposes the equivalent compressive force acting on the intravascular catheter. If compression occurs in the endotracheal catheter, it may not be possible to retract the sheath relative to the stent. Alternatively, the sheath may be withdrawn after the catheter is compressed by a certain amount. As a result, the axial position of the stent may shift within the body lumen. This results in the stent being placed at a location different from the originally intended location. If the stent is not placed at the intended location, it will not be possible to treat the lesion to be treated, which will have a major impact on the therapeutic effect and will require a heavy burden on the patient's body. End up. Prior art stent delivery catheters have been proposed that achieve superior stent placement and are beneficial for stent delivery. These are disclosed in Patent Documents 1 to 4, for example.

  In the structure having a locking stay on the shaft as described in Patent Document 1, the operation of releasing the stent and the mechanism for holding the stent are independent and complicated structures, so that the catheter can be made smaller. It becomes difficult and it becomes impossible to realize a minimally invasive treatment.

  Moreover, in the structure which changes the expansion force of a stent center part and a stent edge part as described in patent document 2, since the stent design is changed by a center part and an edge part, the change part In this case, stress concentration occurs, and the stent may be damaged by the pulsation of the blood vessel and various movements.

  Further, in a structure in which a stabilizing element and a movable member are provided in the catheter as described in Patent Document 3 and control is performed in the operation unit, the structure of the catheter and the operation member becomes complicated, and the catheter is more It becomes difficult to reduce the size, and a minimally invasive treatment cannot be realized.

  In addition, reducing the release load by applying a hydrophilic coating on the inner surface of the outer tube as described in Patent Document 4 removes the coating by contact with the stent, leaving the coating peeled off in the body. The possibility of doing this cannot be denied.

Japanese Patent No. 3679466 JP 2008-193 A JP-T-2002-525168 Special table 2003-510134 gazette

  When operating the sheath to place the stent in the affected area, if the operation resistance is too high, the stent cannot be placed, and even if it can be placed, the stent must be placed at a location different from the originally intended location. Bring. The above phenomenon greatly affects the therapeutic effect and places a heavy burden on the patient's body.

  In view of these situations, the problem to be solved by the present invention is that a stable operation can be performed without requiring excessive force when operating the sheath (catheter body) in order to place the stent in the lesion. It is possible to provide a stent delivery catheter that has excellent operability with respect to a bent passage and can accurately place a stent in a target site.

As a result of intensive studies in view of the above problems, the present inventor,
(1) A stent for disposing a self-expanding stent formed in a substantially tubular body and radially expandable from a compressed first diameter to a second expanded diameter at a target site in a blood vessel A delivery catheter comprising a proximal end and a distal end, an elongated flexible body insertable into a blood vessel having a lumen therein and a stent holder for holding the stent in the vicinity of the distal end A catheter body, and an inner catheter having a proximal end and a distal end at least partially inserted into a lumen formed in the catheter body, the inner catheter having a tubular member having a guide wire lumen; A core wire disposed outside or on the wall surface of the tubular member, and a flexible coating disposed so as to cover the periphery of the tubular member and the core wire. And a stopper for preventing the stent from moving proximally when the catheter body is moved proximally relative to the inner catheter. Provided. According to this, when manipulating a catheter body (hereinafter, also referred to as a sheath) for placing a stent, an excessive force is not required and the catheter body can be stably manipulated. In addition, compared with the prior art, it has excellent operability with respect to the bent passage, and the stent can be accurately placed in the target site.

  (2) The stent delivery catheter is characterized in that the core wire is arranged in parallel to the outer side of the tubular member.

  (3) The stent delivery catheter is characterized in that the catheter body has a three-layer structure including an outer layer made of a resin, an intermediate layer made of a metal material, and an inner layer made of a resin.

  (4) The stent delivery catheter is provided in which the Shore hardness of the covering member is 55D or less.

  (5) In at least a part of the cross section perpendicular to the catheter axis, the difference between the inner diameter of the lumen formed in the catheter body and the maximum outer diameter composed of the tubular member, the core wire, and the covering member of the inner catheter is The stent delivery catheter is characterized by being 0.20 mm or less.

  (6) The stent delivery catheter is provided in which at least a part of the covering member and / or the core wire has a coil shape.

  According to the present invention, when a sheath (catheter body) is operated to place a stent in a lesion, an excessive force is not required and the operation can be performed stably. In addition, compared with the prior art, it has excellent operability with respect to the bent passage, and the stent can be accurately placed in the target site.

FIG. 1 is an overall view (side sectional view) of a stent and a stent delivery catheter. FIG. 2 is an enlarged view of a cross section perpendicular to the catheter axis of the stent delivery catheter. FIG. 3 is a diagram showing a method for evaluating stent discharge load and stent placement accuracy using a lower limb simulated blood vessel.

  Hereinafter, a stent delivery catheter according to the present invention will be described with reference to an example of the drawings, but the present invention is not limited to this specific structure.

  FIG. 1 shows an overall view (side sectional view) of one embodiment of the stent delivery catheter of the present invention. Reference numeral 101 denotes an elongated flexible catheter body that can be inserted into a lumen, and has a stent holding portion 103 that holds a stent at a distal portion thereof. An inner catheter 105 is inserted into a lumen 104 formed in the catheter body 101. The inner catheter 105 includes a tubular member 201 having a guide wire lumen therein, a core wire 203 arranged in parallel to the outside of the tubular member 201, and covers the periphery of the tubular member 201 and the core wire 203. And a stopper 106 for preventing the stent from moving proximally at the same time when the catheter body is moved proximally relative to the inner catheter. (Preferably, it is disposed on the proximal side of the stent 102 and supports the stent 102 from the proximal side.). Further, the distal end of the inner catheter 105 has a guide wire lumen inside and extends distally from the distal end of the catheter body 101 to constitute the tip tip 107 (the tip tip 107 is simultaneously formed with the guide wire). Constitutes the distal opening of the lumen.). Furthermore, an operation member 108 used when the catheter body is moved relative to the inner catheter is provided near the proximal end of the catheter body 101. Hereinafter, each of these components will be sequentially described.

  The stent 102 is held in the stent holding portion 103 in a reduced diameter state (preferably stored). The stent 102 is a self-expanding stent that expands and treats a stenosis of a blood vessel. When the restriction by the stent holder 103 is released, the stent 102 expands so that its inner diameter becomes equal to or larger than the outer diameter of the stent holder 103. Form the outer diameter after expansion. The stent 102 is preferably formed by arranging a plurality of tubular sections, each of which is formed of a substantially corrugated component that is extensible in the circumferential direction, perpendicular to the axial direction. Moreover, it is preferable that the substantially waveform component is comprised by the strut. The outer diameter and axial length of the stent 102 are selected according to the inner diameter and length of the lesioned lumen, and are completely different depending on the target lumen. For example, a stent for the superficial femoral artery is used. For example, the outer diameter is preferably set to 6.0 mm to 10.0 mm and the axial length is set to about 30 to 200 mm. As the stent, generally, a nickel-titanium alloy pipe subjected to laser cutting and subjected to a heat treatment by expanding the diameter is used.

  The inner catheter 105 is at least partially inserted into a lumen 104 formed in the catheter body 101, and a guide wire is inserted into a guide wire lumen 202 provided in a tubular member 201 included in the inner catheter 105. Lead 101 to the lesion. In addition, the inner catheter 105 preferably has flexibility to follow the lumen to be inserted, kink resistance, and tensile strength that does not extend when the catheter is pulled during the procedure. When the catheter is moved relative to the inner catheter, the sliding resistance with the inner peripheral surface of the catheter body 101 is reduced, and the stent holding portion 103 can be easily moved. It is desirable that the surface has low friction (has a low coefficient of friction).

  From the viewpoint of satisfying the above characteristics, the inner catheter 105 is formed in a tubular member 201 having a guide wire lumen 202, outside the tubular member 201, or in a wall surface, as shown in FIG. On the other hand, the core wires 203 arranged in parallel (in particular, from the viewpoint of ease of processing and strength, as shown in FIG. Preferably, it has a structure comprising a tubular member 201 and a covering member 204 disposed so as to cover the periphery of the core wire 203. Further, the tubular member 201 and the covering member 204 are made of a resin material, and the core wire 203 Is preferably made of a metal material. Moreover, it is one of the possible embodiments of the present invention that the covering member 204 is bonded or welded around the tubular member 201 and the core wire 203, and the provision of two or more core wires 203 is a possible implementation of the present invention. One of the forms.

  The inner catheter 105 shown in FIG. 1 includes a tubular member 201, a core wire 203, and a covering member 204 around the proximal side of the stopper 106, and further includes a guide wire lumen around the proximal operation portion 108. In addition to such a structure, the entire proximal side of the stopper 106 may be constituted by the tubular member 201, the core wire 203, the covering member 204, or a rapid exchange type structure. As such, the guide wire lumen may be guided to the outside along the way.

  In addition, the distance between the inner wall of the lumen 104 formed on the catheter body 101 and the outer wall of the inner catheter 105 affects the sliding resistance when releasing the stent, and is preferably optimized. For this reason, the difference between the inner diameter 205 of the lumen 104 formed in the catheter body 101 and the maximum outer diameter 206 of the cross section made of the tubular member 201, the core wire 203, and the covering member 204 is 0.20 mm or less. It is further preferable to do so.

  As a constituent material of the covering member 204 of the inner catheter 105, for example, polyethylene, fluororesin (polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), etc.), polyamide, polyamide elastomer, polyimide And various elastic resin materials such as polyurethane, polyester, and silicone. In addition, when operating the sheath (catheter body) to place the stent in the lesion, it does not require excessive force and can be operated stably (operability during stent placement). In particular, it is preferable that the covering member 204 is made of a flexible resin material having a Shore hardness of 55D or less. Furthermore, it is preferable that the shape of the covering member 204 has a coil shape in part in order to obtain excellent operability (followability) with respect to the bent passage.

  On the other hand, examples of the constituent material of the core wire 203 of the inner catheter 105 include various metal materials such as stainless steel, nickel titanium alloy, tungsten, gold, and platinum. Moreover, it is preferable that the core wire 203 has a coil shape at a part thereof in order to obtain excellent operability (followability) with respect to the bent path.

  The stent holding portion 103 preferably has flexibility that can follow the insertion lumen, kink resistance, and tensile strength that does not extend when the catheter is pulled during the procedure. In addition, the stent holding surface of the stent holding portion 103 (the inner surface of the stent holding portion 103 when the stent holding portion 103 stores the stent 102) holds the stent when the catheter body moves relative to the inner catheter. The stent holding surface (when the stent holding part 103 stores the stent 102, the stent holding part so that the sliding resistance with the stent 102 in contact with the part 103 is reduced and the moving operation can be easily performed). It is desirable that the inner surface 103 has a low friction property (a low friction coefficient). Moreover, it is preferable that a part of the stent holding portion 103 is blasted to roughen the surface and further have low friction.

  From the viewpoint of satisfying the above characteristics, the stent holding portion 103 is a three-layer resin-metal composite tube in which the outer layer and the inner layer are formed of a resin material, and a metal wire (reinforcing layer) is embedded between the outer layer and the inner layer. Preferably, the outer layer is made of, for example, polyethylene, fluororesin (polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), etc.), polyamide, polyamide-based elastomer. And various elastic resin materials such as polyurethane, polyester, and silicone.

  In addition, as a constituent material of the said metal strand, various metal materials, such as stainless steel, nickel titanium alloy, tungsten, gold | metal | money, platinum, are mentioned, for example. The metal strand is preferably formed from a proximal end to a distal end of the stent holding portion in a braided structure or a coil structure. Examples of the constituent material of the inner layer include a low friction material such as fluororesin (polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), etc.) and polyethylene. On the other hand, the stent holding part may be formed of a single-layer tube. As a constituent material, for example, a fluororesin (polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), etc.) And low friction materials such as polyethylene.

  Moreover, it is preferable to have a stopper 106 that prevents the stent 102 from moving proximally when the catheter body 101 is moved relatively proximal to the inner catheter 105. The stopper 106 is preferably bonded or welded to the inner catheter 105. The outer diameter of the stopper 106 is preferably smaller than the inner diameter of the stent holding portion 103 and larger than the inner diameter of the stent 102 that is crimped and held in the stent holding portion 103. As a result, the wall surface of the proximal end of the stent 102 can be supported (pushed) over the entire circumference, so that the stent 102 can be more efficiently moved when the catheter body 101 is moved relative to the inner catheter 105. A stent delivery catheter that can be released can be provided.

  The constituent material of the stopper 106 is preferably a metal, a resin material or the like, for example, a metal material such as stainless steel, nickel titanium alloy, cobalt chrome alloy, polyethylene, fluororesin (polytetrafluoroethylene (PTFE), tetrafluoroethylene). -Various elastic resin materials such as perfluoroalkyl vinyl ether copolymer (PFA), polyamide, polyamide-based elastomer, polyurethane, polyester, silicone and the like are preferable.

  The stopper 106 is preferably made of a radiopaque material and functions as a radiopaque marker. As a result, the catheter body 101 can be advanced to the lesioned part in the body lumen under fluoroscopy, and the positional relationship between the stent 102 and the catheter body 101 can be confirmed when placing the stent. A stent delivery catheter capable of transporting and releasing a stent safely and efficiently can be provided.

  The radiopaque marker is formed of a contrast-enhancing substance such as an X-ray contrast-enhancing substance or a contrast-enhancing substance such as an ultrasound contrast-enhancing substance. As the constituent material of the marker, for example, gold, platinum, tungsten, tantalum, iridium, palladium or an alloy thereof, or a gold-palladium alloy, platinum-iridium, NiTiPd, NiTiAu, or the like is preferable.

  Further, it is preferable that the distal tip 107 is disposed on the distal end portion of the inner catheter 105 by, for example, bonding or welding. In particular, as in the embodiment shown in FIG. 1, it is preferable to have a tip tip 107 that is provided with a guide wire lumen inside and that extends distally from the distal end of the catheter body 101. (Thus, the tip 107 simultaneously constitutes the distal opening of the guidewire lumen.) The distal tip 107 makes it easier for the catheter body 101 to pass through the lesion (stenosis). Moreover, it is preferable that the front-end | tip chip | tip 107 has contrast property. Accordingly, the distal end portion of the catheter main body 101 can be grasped, and the relative position of the stent 102 with respect to the stent holding portion 103 can be grasped by the operation of the operation portion 108.

  The distal tip 107 preferably has a flexibility capable of following the lumen to be inserted and has a long-axis rigidity capable of passing through the narrowed portion. For example, various elastic resin materials such as polyethylene, fluororesin (polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), etc.), polyamide, polyamide-based elastomer, polyurethane, polyester, silicone, etc. It is done. Furthermore, it is preferable that barium sulfate, a bismuth compound, a tungsten compound, etc. contain from the viewpoint of adding contrast.

  Below, although the stent delivery catheter concerning the present invention is explained based on an example, the present invention is not restricted to this.

Example 1
A tube having a braided structure using a polyamide elastomer for the outer layer and polytetrafluoroethylene (PTFE) for the inner layer and a stainless steel flat wire having a width of 100 μm and a thickness of 25 μm as the reinforcing layer was used as the catheter body 101. The inner diameter 205 of the lumen 104 formed on the catheter body 101 was 1.78 mm.

  In the inner catheter 105, a core wire 203 made of stainless steel is disposed outside the tubular member 201 made of polyimide so as to be parallel to the tubular member 201, and further, a covering member made of polyamide elastomer having a Shore hardness of 55D. It was created by winding 204 to cover the periphery. The maximum outer diameter 206 of the cross section perpendicular to the catheter axis of the inner catheter 105 composed of the tubular member 201, the core wire 203, and the covering member 204 was 1.60 mm. Further, the inner catheter 105 was inserted into the lumen of the catheter body 101 to create a stent delivery catheter (note that the operation member 108 for moving the catheter body relative to the inner catheter was replaced with the catheter body 101). Provided near the proximal end).

  On the other hand, in the stent delivery catheter, the vicinity of the distal end of the lumen of the catheter body was used as the stent holding portion 103, and the self-expanding stent 102 was housed and held. The stent 102 is obtained by laser-cutting a φ2.2 mm nickel-titanium (Ni—Ti) alloy pipe and expanding the pipe to φ6 mm and performing heat treatment. Before being held by the stent holder 103, the stent 102 had an outer diameter of 6 mm and an axial length of 45 mm.

(Comparative Example 1)
A tube having a braided structure using a polyamide elastomer for the outer layer and polytetrafluoroethylene (PTFE) for the inner layer and a stainless steel flat wire having a width of 100 μm and a thickness of 25 μm as the reinforcing layer was used as the catheter body 101. The inner diameter 205 of the lumen 104 formed on the catheter body 101 was 1.78 mm.

  In the inner catheter 105, a core wire 203 made of stainless steel is arranged outside the tubular member 201 made of polyimide so as to be parallel to the outer side. The maximum outer diameter 206 of the cross section perpendicular to the catheter axis of the inner catheter 105 made of the tubular member 201 and the core wire 203 was 1.22 mm. Further, the inner catheter 105 was inserted into the lumen of the catheter body 101 to create a stent delivery catheter (note that the operation member 108 for moving the catheter body relative to the inner catheter was replaced with the catheter body 101). Provided near the proximal end).

  On the other hand, in the stent delivery catheter, the vicinity of the distal end of the lumen of the catheter body was used as the stent holding portion 103, and the self-expanding stent 102 was housed and held. The stent 102 is obtained by laser-cutting a φ2.2 mm nickel-titanium (Ni—Ti) alloy pipe and expanding the pipe to φ6 mm and performing heat treatment. Before being held by the stent holder 103, the stent 102 had an outer diameter of 6 mm and an axial length of 45 mm.

(Comparative Example 2)
A tube having a braided structure using a polyamide elastomer for the outer layer and polytetrafluoroethylene (PTFE) for the inner layer and a stainless steel flat wire having a width of 100 μm and a thickness of 25 μm as the reinforcing layer was used as the catheter body 101. The inner diameter 205 of the lumen 104 formed on the catheter body 101 was 1.78 mm.

  In the inner catheter 105, a core wire 203 made of stainless steel is arranged outside the tubular member 201 made of polyimide so as to be parallel to the tubular member 201, and further, a covering member made of polyamide elastomer having a Shore hardness of 72D. It was created by winding 204 to cover the periphery. The maximum outer diameter 206 of the cross section perpendicular to the catheter axis of the inner catheter 105 composed of the tubular member 201, the core wire 203, and the covering member 204 was 1.60 mm. Further, the inner catheter 105 was inserted into the lumen of the catheter body 101 to create a stent delivery catheter (note that the operation member 108 for moving the catheter body relative to the inner catheter was replaced with the catheter body 101). Provided near the proximal end).

  On the other hand, in the stent delivery catheter, the vicinity of the distal end of the lumen of the catheter body was used as the stent holding portion 103, and the self-expanding stent 102 was housed and held. The stent 102 is obtained by laser-cutting a φ2.2 mm nickel-titanium (Ni—Ti) alloy pipe and expanding the pipe to φ6 mm and performing heat treatment. Before being held by the stent holder 103, the stent 102 had an outer diameter of 6 mm and an axial length of 45 mm.

  (Evaluation) The following evaluation was performed on Example 1 and Comparative Examples 1 and 2.

(1) Evaluation of stent release load As shown in FIG. 3, a stent delivery catheter in which a lower limb simulated blood vessel 304 (simulated lesion site) is placed in a warm bath 303 controlled at 37 ° C. ± 2 ° C. The lower limb simulated blood vessel 304 was inserted. In addition, it is confirmed whether the stent 102 can be delivered to the lower limb simulated blood vessel 304 without being deployed (stent delivery correct / incorrect), and for the delivered one, the operation member 108 of the catheter body 101 is moved with a training distance of 80 mm. The stent was loaded at a speed of 10 mm / sec toward the proximal end, and the stent release load generated at that time was measured using a 20N force gauge 306 (Nidec Symposium). Evaluation was performed when the catheter body 101 started to move with respect to the stent 102 in which the number of samples was three and the movement toward the proximal end side by the inner catheter 105 was suppressed in each of Example 1 and Comparative Examples 1 and 2. The average of the load values was evaluated as the stent discharge load.

(2) Evaluation of stent placement deviation At the time of the above-mentioned stent release load evaluation, the stent placement deviation generated when releasing the stent 102 from the catheter was evaluated. Specifically, the initial position of the distal end of the stent holding portion 103 is marked on the lower limb simulated blood vessel 304 before the stent is released, and the catheter body 101 is pulled to the proximal end side and placed. The distance from the distal end of 102 to the marked location was measured. In the evaluation, in Example 1 and Comparative Examples 1 and 2, the number of samples was set to 3, and the average of the displacement was obtained.

  (Evaluation results)

  Table 1 shows the evaluation results of delivery correctness, stent release load, and stent placement deviation. As shown in Table 1, both Example 1 and Comparative Examples 1 and 2 were able to be delivered to the virtual lesion site and the stent 102 could be released. In Example 1, compared with Comparative Examples 1 and 2, the stent release load was greatly reduced. Moreover, in Example 1, the stent placement deviation decreased compared with Comparative Examples 1 and 2, and the stent placement accuracy was improved.

DESCRIPTION OF SYMBOLS 101 Catheter main body 102 Stent 103 Stent holding | maintenance part 104 Catheter main body lumen 105 Inner catheter 106 Stopper 107 Tip 108 Operation part 201 Tubular member 202 Guide wire lumen 203 Core wire 204 Covering member 205 Catheter main body lumen inner diameter 206 Inner catheter cross section (201, 203, 204) Maximum outer diameter 301 Stent delivery catheter 302 Stent 303 Warm bath 304 Model simulating lower limb blood vessels 305 Slider 306 Force gauge

Claims (6)

A stent delivery catheter for deploying a self-expanding stent formed in a generally tubular body and radially expandable from a compressed first diameter to an expanded second diameter at a target site in a blood vessel There,
An elongate flexible catheter body insertable into a blood vessel having a proximal end and a distal end, and a stent holding portion for holding the stent in the vicinity of the distal end of the lumen;
An inner catheter having a proximal end and a distal end at least partially inserted into a lumen formed in the catheter body;
The inner catheter is disposed so as to cover a tubular member having a guide wire lumen, a core wire disposed in parallel to the outside or the wall surface of the tubular member, and surrounding the tubular member and the core wire. And a stopper that prevents the stent from moving proximally when the catheter body is moved proximally relative to the inner catheter. , Stent delivery catheter.   The stent delivery catheter according to claim 1, wherein the core wire is disposed in parallel to the outer side of the tubular member.   3. The catheter body according to claim 1, wherein the catheter body has a three-layer structure including an outer layer made of a resin, an intermediate layer made of a metal material, and an inner layer made of a resin. 4. Stent delivery catheter.   The stent delivery catheter according to any one of claims 1 to 3, wherein the covering member has a Shore hardness of 55D or less.   In at least a part of the cross section perpendicular to the catheter axis, the difference between the inner diameter of the lumen formed in the catheter body and the maximum outer diameter composed of the tubular member, the core wire and the covering member of the inner catheter is 0.20 mm. The stent delivery catheter according to any one of claims 1 to 4, wherein:   The stent delivery catheter according to any one of claims 1 to 5, wherein at least a part of the covering member and / or the core wire has a coil shape.

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