JP3585978B2 - Instrument for treating stenosis in body cavity - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a device for treating a stenosis in a body cavity used for improving a stenosis formed in a living body such as a blood vessel, a bile duct, a trachea, an esophagus, a urethra, and other organs.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been proposed a device for treating a stenosis in a body cavity in which a stent is placed in a stenosis of a living body lumen or a body cavity such as a blood vessel, a bile duct, an esophagus, a trachea, a urethra, and other organs to secure a lumen or a body cavity space. Have been.
As the stents constituting the therapeutic device, there are a balloon expandable stent and a self-expandable stent depending on the function and the placement method.
[0003]
The balloon expandable stent has no expansion function in the stent itself.In order to place the stent at the target site, for example, after inserting the stent to the target site, the balloon is positioned inside the stent, the balloon is expanded, and the balloon is expanded. The stent is expanded (plastically deformed) by the expanding force, and is fixed in close contact with the inner surface of the target portion.
This type of stent requires the operation of expanding the stent as described above. However, since the stent can be directly attached to the deflated balloon and placed, there is not much problem with the placement. However, since the stent itself does not have an expanding force, the diameter decreases over time due to pressure of a blood vessel or the like, and there is a high possibility that restenosis occurs.
[0004]
On the other hand, in the self-expandable stent, the stent itself has contraction and expansion functions. In order to place the stent at the target site, the stent is inserted into the target site in a contracted state, and then the stress applied for maintaining the contracted state is removed. For example, the stent is contracted and stored in a sheath having an outer diameter smaller than the inner diameter of the target portion, and after the distal end of the sheath reaches the target portion, the stent is pushed out of the sheath. When the extruded stent is released from the sheath, the stress load is released, and the stent is restored to the shape before contraction and expanded. Thereby, it adheres and fixes to the inner surface of the target part.
This type of stent does not require an expansion work like a balloon expandable stent because the stent itself has an expanding force, and there is no problem that the diameter gradually decreases due to the pressure of the blood vessel and restenosis occurs. .
[0005]
[Problems to be solved by the invention]
However, on the other hand, since the stent itself attempts to expand, it is difficult to place the stent in a body cavity. Especially in a thin and highly bent blood vessel such as a coronary artery, it is extremely difficult to place a stent at an accurate position because a stent placement device (sheath and catheter) uses a more flexible one.
[0006]
For example, as shown in FIG. 12, there is a conventional self-expandable stent indwelling device (Japanese Patent Application No. 62-501271).
This device comprises a probe 70, a catheter 71 having one end 71a attached to the probe 70 and bent to form a double structure, and a stent 72 housed between the probe 70 and the catheter 71. . By moving the probe 70 in the axial direction, the stent 72 is pushed out of the catheter 71 and is placed in the body cavity. However, with such a structure, the portion in which the stent 72 is stored becomes hard, and it is difficult to use the stent 72 in a narrow and coronary coronary artery. Further, there is no device for accurately placing the coronary artery at a target site in a finely bent coronary artery. In addition, it is difficult to manufacture because a very thin catheter is formed by being folded twice.
[0007]
As described above, conventionally, there has been no stent placement device (assembly) capable of placing the self-expandable stent accurately in a thin and sharply bent blood vessel such as a coronary artery.
Therefore, an object of the present invention is to provide a self-expandable stent at a target site accurately and easily even in a thin and highly bent blood vessel such as a coronary artery with a simple structure. It is an object of the present invention to provide a device for treatment of head and neck.
[0008]
[Means for Solving the Problems]
What achieves the above-mentioned object is a stent for indwelling in a body cavity, which is formed in a substantially cylindrical shape, the outer diameter of which is compressed when inserted into a living body, and which expands when indwelling in a living body to restore the original shape, and the stent A sheath that is held on the inner surface in a state where the outer diameter of the sheath is compressed, and a balloon catheter that is inserted into the stent and the sheath and has a balloon at a site protruding from the distal end of the sheath and the stent. A projecting portion that comes into contact with the stent when moving toward the rear end of the sheath, behind the site where the stent is housed, and ejects the stent from the distal end of the sheath. And when the balloon catheter alone is moved in the rearward direction, abuts against the distal end surface of the sheath, and balloon protection means for preventing entry of the balloon into the sheath. It is a device for treating a stenosis in a body cavity, which has:
[0009]
Preferably, the protrusion is an annular protrusion having an outer diameter smaller than the inner diameter of the sheath and larger than the inner diameter of the compressed stent. It is preferable that the protrusion is formed of an X-ray contrast material (X-ray negative opaque material). The annular protrusion may be provided integrally with an outer tube of the balloon catheter. The protrusion may be a protrusion provided on an outer tube of the balloon catheter. The convex portion may be plural. It is preferable that the protruding portion has a contact portion that comes into contact with a rear end of the stent in a contracted state.
[0010]
It is preferable that the balloon catheter has balloon protection means at a position behind the balloon and protruding from the sheath. The balloon protection means is preferably an annular protrusion having an outer diameter larger than the inner diameter of the sheath. The instrument for treating a stenosis in a body cavity preferably has fixing means for releasably fixing the sheath to the balloon catheter. The fixing means is a lock mechanism provided on the balloon catheter, the sheath, or both.
[0011]
[Action]
Since the instrument for treating a stenosis in a body cavity of the present invention has a balloon catheter having a balloon at a site protruding from the distal end of the stent and the sheath, the balloon is inflated at the stenosis before the stent is placed. Thus, the stenosis can be expanded to some extent. Further, by inflating the balloon in front of the stenosis, the position can be fixed even in a thin and sharply bent blood vessel such as a coronary artery. Therefore, the self-expandable stent can be accurately placed at the target site.
Further, in the device for treating a stenosis in a body cavity according to the present invention, the balloon catheter has a protruding portion behind the portion where the stent is located for locking the movement of the stent accompanying the movement toward the rear end of the sheath. Since the stent held by the sheath is positioned at the stenosis, the stent is moved toward the rear end, so that the stent comes into contact with the protrusion, protrudes from the distal end opening of the sheath, and enters the stenosis. To improve the stenosis and to be fixed within the stenosis.
[0012]
【Example】
A device for treating a stenosis in a body cavity according to the present invention will be described with reference to an embodiment shown in the drawings.
FIG. 1 is a front view of an embodiment of the instrument for treating a stenosis in a body cavity of the present invention, and FIG. 2 is a schematic view showing the vicinity of the distal end of the instrument for treating a stenosis in a body cavity shown in FIG. 3 is a partially enlarged cross-sectional view of FIG. 2, FIG. 4 is a perspective view of one embodiment of a stent for indwelling in a body cavity used in the device for treating a stenosis in a body cavity of the present invention, and FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view of one Example of the stent for indwelling in a body cavity used for the device for treating a stenosis in a body cavity.
[0013]
The instrument 1 for treating a stenosis in a body cavity according to this embodiment is formed in a substantially cylindrical shape as shown in FIG. 2, and is compressed and contracted when inserted into a living body, and expanded and restored to its original shape when placed in a living body. A stent 4 holding the stent 2 in a contracted state on its inner surface, and a balloon 4 inserted into the stent 2 and the sheath 3 and protruding from the distal ends of the stent 2 and the sheath 3. The balloon catheter 5 includes the balloon catheter 5, and the balloon catheter 5 comes into contact with the stent 2 when moving toward the rear end of the sheath 3 behind the portion where the stent 2 is stored, and discharges the stent 2 from the distal end of the sheath 3. Has a protruding portion 6.
[0014]
As shown in FIG. 2 or FIG. 3, the balloon catheter 5 inserted into the substantially cylindrical stent 2 and the sheath 3 includes an inner tube 55 having a first lumen 54 having an open end, and an inner tube 55. An outer tube 52 provided coaxially, having a distal end at a position receded from the distal end of the inner tube 55 by a predetermined length, and forming a second lumen 56 with the outer surface of the inner tube 55; A retractable or foldable balloon 4 having a proximal end attached to the outer tube 52, a distal end attached to the inner tube 55, and communicating with the second lumen 56 near the proximal end; A branch hub 80 provided at the proximal end of the tube 55. The branch hub 80 includes a first opening 59 communicating with the first lumen 54 as shown in FIG. 7 and a second opening provided at the base end of the outer tube 52 and communicating with the second lumen 56. And a portion 51.
[0015]
As shown in FIG. 3, the inner tube 55 has a first lumen 54 having an open end. The first lumen 54 is a lumen through which a guide wire 90 is inserted, and communicates with a first opening 59 provided in a guide wire port 58 provided in a branch hub 80 described later. The inner tube 55 has an outer diameter of 0.40 to 2.50 mm, preferably 0.55 to 2.40 mm, and an inner diameter of 0.25 to 2.35 mm, preferably 0.30 to 1.80 mm. . The inner tube 55 of this embodiment has an outer diameter of 0.52 mm, an inner diameter of 0.43 mm, and a wall thickness of 0.045 mm.
[0016]
The distal end of the inner tube 55 is preferably tapered toward the distal end. This facilitates insertion into a blood vessel. As shown in FIG. 3, the inner tube 55 is inserted into an outer tube 52, which will be described later, and has a distal end projecting from the outer tube 52. A second lumen 56 is formed by the outer surface of the inner tube 55 and the inner surface of the outer tube 52, and has a sufficient volume. Then, the second lumen 56 communicates with the inside of the balloon 4 at the distal end, and the rear end of the second lumen 56 is a fluid (for example, an angiographic agent) for inflating the balloon 4 as shown in FIG. And is communicated with a second opening 51 provided in an injection port 57 for injecting a gas.
[0017]
An X-ray contrast part 9 is provided in the inner tube 55 at a position located inside the balloon 4 described later. In this embodiment, as shown in FIG. 2, the formation position of the X-ray contrast part 9 is near the center of the balloon 4 in the axial direction. Thereby, the position of the balloon 4 can be accurately grasped under X-rays, and the procedure becomes easier. As a method of forming the X-ray contrast part, a ring or coil formed of a metal of an X-ray opaque material (for example, gold, platinum, platinum-iridium alloy, silver, stainless steel, platinum, or an alloy thereof) is used. A method of forming by caulking the outer surface of the tube 55 is considered.
[0018]
The outer tube 52 has an outer diameter of 0.60 to 2.80 mm, preferably 0.80 to 2.60 mm, and an inner diameter of 0.50 to 2.70 mm, preferably 0.60 to 2.00 mm. . In particular, the difference between the outer diameter of the inner tube 55 and the inner diameter of the outer tube 52 is 0.05 to 0.20 mm, preferably 0.1 to 1.20 mm. The thickness of the outer tube 52 is 0.05 to 0.75 mm, preferably 0.07 to 0.3 mm. The outer tube 52 of this embodiment has an outer diameter of 1.0 mm, an inner diameter of 0.80 mm, and a thickness of 0.1 mm.
[0019]
As a material for forming the inner tube 55 and the outer tube 52, a material having a certain degree of flexibility is preferable. For example, polyolefin (eg, polyethylene, polypropylene, ethylene-propylene copolymer, etc.), polyvinyl chloride, ethylene -Thermoplastic resins such as vinyl acetate copolymers, polyamide elastomers and polyurethanes, silicone rubbers and the like can be used, preferably the thermoplastic resins described above, and more preferably polyolefins.
Further, the outer surface of the outer tube 52 may be coated with a resin having biocompatibility, particularly antithrombotic properties. As the antithrombotic material, for example, polyhydroxyethyl methacrylate, a copolymer of hydroxyethyl methacrylate and styrene (for example, a HEMA-St-HEMA block copolymer) and the like can be suitably used.
[0020]
In the balloon catheter 5 according to the present invention, as shown in FIG. 2, the balloon 4 is located at a position protruding from the distal ends of the stent 2 and the sheath 3. By the presence of the balloon at such a site, the balloon can be inflated at the stenosis portion before the stent is placed, and the stenosis portion can be expanded to some extent. Further, by inflating the balloon in front of the stenosis, the position can be fixed even in a thin and sharply bent blood vessel such as a coronary artery, and the self-expandable stent can be accurately placed at the target site.
[0021]
The balloon 4 can be deflated or folded, and is in a state of being closely attached or folded to the outer periphery of the inner tube 55 when not expanded. The balloon preferably has a certain degree of shape retention and a certain degree of elasticity. In other words, it is preferable that the elasticity is high for fixing the catheter in the blood vessel (body cavity), and that the shape retention is high for improving the stenosis. For this reason, it is preferable that both are provided to some extent. When the balloon 4 has a certain shape-retaining property, the balloon 4 has a substantially cylindrical portion 43a having a substantially cylindrical shape and having a substantially cylindrical shape so that the stenotic portion of the blood vessel can be more reliably expanded. Is preferred. The substantially cylindrical portion 43a may not be a perfect cylinder, but may be a polygonal column. Further, in the balloon 4, the front and rear portions of the cylindrical portion 43a are tapered. As the size of the balloon 4, the outer diameter of the cylindrical portion when expanded is 1.50 to 35.00 mm, preferably 2.00 to 30.00 mm, and the length is 10.00 to 80.00 mm. , Preferably 15.00 to 75.00 mm, and the entire length of the expansion body 3 is 15.00 to 120.00 mm, preferably 20.00 to 100.00 mm. The balloon may have low shape retention and high elasticity.
[0022]
As shown in FIG. 2 or FIG. 3, the balloon 4 has a rear end portion 48 fixed to a front end portion of the outer tube 52 in a liquid-tight manner by an adhesive or heat fusion, and a front end portion 47 has a front end portion of the inner tube 55. Similarly, it is fixed in a liquid-tight manner. The balloon 4 forms an expansion space 45 between the inner surface of the balloon 4 and the outer surface of the inner tube 55.
[0023]
As the material for forming the balloon, those having a certain degree of flexibility, shape retention and stretchability are preferable. For example, polyethylene, polypropylene, polyolefin such as ethylene-propylene copolymer, polyvinyl chloride, ethylene-vinyl acetate copolymer, etc. Polymers, crosslinked ethylene-vinyl acetate copolymers, polyurethanes, polyesters such as polyethylene terephthalate, and thermoplastic resins such as polyamide elastomers are conceivable. Silicone rubber, latex rubber, and the like can be considered as materials having high elasticity for forming the balloon.
[0024]
Further, it is preferable that the outer surface of the catheter protruding from the balloon 4 and the sheath has lubricity. For this purpose, for example, a hydrophilic polymer such as poly (2-hydroxyethyl methacrylate), polyhydroxyethyl acrylate, hydroxypropyl cellulose, methyl vinyl ether maleic anhydride copolymer, polyethylene glycol, polyacrylamide, or polyvinylpyrrolidone is coated, or It may be fixed. Also, the above may be coated or fixed on the entire outer surface of the catheter. Further, in order to improve the slidability with the guide wire, the above may be coated or fixed on the inner surface of the catheter.
[0025]
As shown in FIG. 7, the branch hub 80 has a guide wire port 58 that allows the first lumen 54 to communicate with the first opening 59, and is fixed to the inner pipe 55. An outer tube hub 83 having an injection port 57 for communicating the second lumen 56 with the second opening 51 and fixed to the outer tube 52 is provided. The outer tube hub 83 and the inner tube hub 82 are fixed.
[0026]
As a material for forming the branch hub, a thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyarylate, and methacrylate-butylene-styrene copolymer can be suitably used. Note that, without providing the branch hub 80, for example, a tube having a port member that forms an opening at the rear end may be attached to each of the first lumen and the second lumen in a liquid-tight manner.
[0027]
Further, in the balloon catheter 5 of this embodiment, a stiffener 11 is attached to the inner surface of the outer tube 52 as shown in FIG. The stiffness imparting body 11 is for preventing bending and enhancing torque characteristics. The stiffness imparting body 11 is preferably provided from the base end to the vicinity of the distal end of the outer tube 52, that is, over the entire length of the outer tube 52, and may be attached to the outer surface of the inner tube 55.
[0028]
The rigidity imparting body 11 is preferably a mesh-shaped rigidity imparting body, and the mesh-shaped rigidity imparting body 11 is preferably formed of a blade wire. For example, it is a wire blade, and can be formed of a metal wire such as stainless steel, an elastic metal, a superelastic alloy, or a shape memory alloy having a wire diameter of 0.01 to 0.2 mm, preferably 0.03 to 0.1 mm. Alternatively, it may be formed of synthetic fibers such as polyamide fibers, polyester fibers, and polypropylene fibers.
[0029]
The balloon catheter 5 according to the present invention abuts against the stent 2 when moving toward the rear end of the sheath 3 behind the site where the stent 2 is located, and discharges the stent 2 from the distal end of the sheath 3. It has a protrusion 6 (rib 6). In other words, the projecting portion 6 is for locking the movement of the stent 2 accompanying the movement of the sheath 3 toward the rear end. As described above, in the device for treating a stenosis in a body cavity of the present invention, since the balloon catheter has a protruding portion, the stent held by the sheath is located in the stenosis, and the sheath is moved in the posterior direction. Accordingly, the stent comes into contact with the protruding portion, the movement is suppressed, and the stent protrudes from the sheath. Therefore, with such a simple structure, the self-expandable stent can be easily placed at a target site even in a thin and highly bent blood vessel such as a coronary artery.
[0030]
As shown in FIG. 3, the protrusion 6 of this embodiment is formed by an annular protrusion (annular rib) having an outer diameter smaller than the inner diameter of the sheath 3 and larger than the inner diameter of the contracted stent 2. Therefore, the protruding portion 6 does not hinder the movement of the sheath 3 in the axial direction. Further, since the projecting portion 6 is annular, the projecting portion 6 surely comes into contact with the stent when the sheath 3 moves forward, so that the stent can be reliably released. .
[0031]
The outer diameter of the protrusion 6 is 1.0 to 3.2 mm, preferably 1.1 to 3.0 mm, and the outer diameter of the protrusion 6 is 90/100 to 100/100 of the inner diameter of the sheath. Preferably, there is. Specifically, the outer diameter of the protrusion 6 in this embodiment is 1.40 mm. As described above, the inner diameter of the sheath 3 is 1.46 mm, and the thickness of the stent 2 is 0.1 mm. Accordingly, the inner diameter of the stent 2 is 1.26 mm, and the stent 2 is sized to be securely locked to the protrusion 6 having an outer diameter of 1.40 mm.
[0032]
However, the protruding portion 6 of the present invention is not limited to such an annular protruding portion, as long as the protruding portion 6 can lock the movement of the stent 2 accompanying the movement of the sheath 3 toward the rear end. Any shape may be used. For example, the protrusion may be a protrusion provided on the outer tube of the balloon catheter. And the projection may be single or plural. That is, the protruding portion has a contact portion that comes into contact with the rear end of the stent in a contracted state, and may be any type as long as the stent can be locked. Further, the protruding portion may be formed as a separate member from the outer tube, or may be provided integrally with the outer tube.
[0033]
Further, it is preferable that the projecting portion 6 is formed of an X-ray opaque material (X-ray opaque material). Thereby, the position of the stent can be accurately grasped under X-ray contrast, and the procedure becomes easier. As a forming method, a projecting portion formed in a ring shape or a coil by using a metal such as an X-ray opaque material (for example, gold, platinum, a platinum-iridium alloy, silver, stainless steel, platinum, or an alloy thereof) is used. Outer tube 52 There is a method of caulking on the outer surface.
[0034]
The stent 2 used in the device 1 for treating a stenosis in a body cavity is a so-called self-expandable stent. Specifically, it has a shape as shown in FIG. 4 (showing a state where it has been expanded and restored to the original shape). The stent 2 of this embodiment has a cylindrical frame body 20, an opening 24 defined (surrounded) by frames 26a and 26b constituting the cylindrical frame body 20, and a cutout 25 defined by the frame 26a. The frame body 20 has both ends 23a and 23b.
[0035]
As a material for forming the stent body, a synthetic resin or a metal is used. As the synthetic resin, a resin having a certain degree of hardness and elasticity is used, and a biocompatible synthetic resin is preferable. Specifically, polyolefin (eg, polyethylene, polypropylene), polyester (eg, polyethylene terephthalate), fluororesin (eg, PTFE, ETFE), or polylactic acid, polyglycolic acid, or polylactic acid that is a bioabsorbable material And copolymers of polyglycolic acid. Further, as the metal, those having biocompatibility are preferable, and examples thereof include stainless steel, tantalum, and nickel titanium alloy. Particularly, a superelastic metal is preferable. It is preferable that the stent main body 2 is integrally formed without forming sudden changes in physical properties as a whole. The stent body, for example, prepare a metal pipe having an outer diameter adapted to the in-vivo site to be placed, and partially remove the side of the metal pipe by cutting, chemical etching, etc. It is created by forming a notch or a plurality of openings.
[0036]
Since the stent 2 has the cutouts 25 at the ends of the frame body 20, the ends 23a and 23b of the stent 2 can be easily deformed. In particular, the ends can be partially deformed, and the deformed blood vessel can be deformed. Good response to time. Further, since the end portion 23 is formed by the end portions of the plurality of frames 26a, it is hard to be crushed and has sufficient strength. An opening 24 surrounded by frames 26a and 26b is formed between both ends, and this opening 24 is easily deformed by deformation of the frame 26a. For this reason, the stent 2 can be easily deformed at its central portion (the central portion of the frame body 20). The shape and the number of the cutouts and the openings are not limited to the illustrated shapes and the numbers. The cutouts are preferably 3 to 10 and the openings are preferably about 3 to 10.
[0037]
The frame body 20 has an outer diameter of 2.0 to 30 mm, preferably 2.5 to 20 mm, an inner diameter of 1.4 to 29 mm, preferably 1.6 to 29.4 mm, and a length of 10 to 20 mm. To 150 mm, more preferably 15 to 100 mm.
[0038]
The shape of the stent is not limited to the stent shown in FIG. 4. For example, a trapezoidal notch is formed at both ends, and a plurality of hexagonal openings are formed in a honeycomb shape at the center, and Alternatively, a rectangular notch may be formed at both ends, and a plurality of rectangular openings (having twice the length of the notch) may be formed at the center.
[0039]
A superelastic alloy is suitably used as the superelastic metal forming the stent. The superelastic alloy mentioned here is generally called a shape memory alloy, and exhibits superelasticity at least at a biological temperature (around 37 ° C.). Particularly preferably, a TiNi alloy of 49 to 53 atomic% Ni, a Cu-Zn alloy of 38.5 to 41.5 wt% Zn, and a Cu-Zn-X alloy of 1 to 10 wt% X (X = Be, Si, Superelastic metal bodies such as Sn, Al, Ga) and a 36-38 atomic% Al-Ni-Al alloy are preferably used. Particularly preferred is the above-mentioned TiNi alloy. Also, a Ti-Ni-X alloy in which a part of the Ti-Ni alloy is substituted with 0.01 to 10.0% X (X = Co, Fe, Mn, Cr, V, Al, Nb, W, B, etc.) Or a Ti—Ni—X alloy (X = Cu, Pb, Zr) in which part of the Ti—Ni alloy is substituted with 0.01 to 30.0% of atoms, and a cold working rate Alternatively, by selecting the conditions of the final heat treatment, the mechanical properties can be appropriately changed. Further, by selecting the cold working ratio and / or the condition of the final heat treatment using the above-mentioned Ti-Ni-X alloy, the mechanical properties can be appropriately changed.
[0040]
The buckling strength (yield stress under load) of the superelastic alloy used is preferably 8 to 150 kg / mm. ² , Restoration stress (yield stress at the time of unloading) is 3 to 180 kg / mm ² (22 ° C.), more preferably 5 to 130 kg / mm ² It is. Superelasticity here means that even if the metal is deformed (bent, tensioned, compressed) to the area where normal metal plastically deforms at the operating temperature, it recovers to almost its original shape without the need for heating after the deformation is released. Means that.
As described above, since the stent 2 is formed of a superelastic alloy and has the above-described shape, the stent 2 is compressed and contracted when inserted into a living body, and expands and restores its original shape when placed in a living body.
[0041]
In addition, the stent 2 of this embodiment is formed by removing (for example, cutting and dissolving) a notch and an opening portion using a superelastic metal pipe, thereby rapidly changing the physical properties. It is an integrally formed product with no dots formed. If there is a sudden change in physical properties, that part will show a different deformation kinetics than the other parts. Further, there is a risk that metal stress is applied to a portion having different physical properties and the portion is damaged. In addition, if there is a change in the physical properties, the stent as a whole becomes unnaturally deformed, an unnatural flow is formed in the blood flow flowing inside, and again causes stenosis. However, the stent according to the present invention does not have the above-described problem because it is formed of an integrated product in which abrupt changes in physical properties are not formed.
[0042]
The shape of the stent body 2 is not limited to the shape described above, as long as the diameter can be reduced at the time of insertion and the diameter can be expanded (restored) at the time of release into the body. For example, it may be a coil, a cylinder, a roll, a deformed tube, a higher coil, a leaf spring coil, a basket or a mesh.
[0043]
Further, the stent constituting the device for treating a stenosis in a body cavity of the present invention may be as shown in FIG. The stent 42 according to this embodiment has a substantially cylindrical stent body 42a that can be reduced in diameter, a thermoplastic resin layer covering the stent body 42a, and a side wall of the stent body 42a. And a cylindrical cover 43 fixed to the cover. The difference between the stent 42a and the above-described stent 2 is that the side wall (outer or inner or outer or inner peripheral surface) of the stent body 42a is covered (closed) by the cylindrical cover 43. For this reason, since the communicating portion (hole) formed in the side wall of the stent such as the opening and the cutout portion of the stent body 42a is closed by the cover, it is possible to prevent the living tissue from entering the stent from the outside. In addition, the tubular cover 43 is thermally fused to the thermoplastic resin, so that the tubular cover 43 does not peel off from the stent body 42a, and the two do not separate during and after placement of the stent. .
[0044]
The stents 2 and 42 formed as described above are held on the inner wall surface near the distal end of the sheath 3 in a contracted state. Since the stent 2 has an expanding force as described above, the stent 2 presses the inner wall surface of the sheath 3 in the radial direction by itself and is held in a state of sticking.
[0045]
The sheath 3 is a tubular body as shown in FIG. 1 or 3, and has a front end opening 30 and a rear end opening (not shown) at the front and rear ends. The distal end opening 30 is a discharge port of the stent 2 when the stent 2 is placed in a stenosis in a body cavity. When the stent 2 is detached from the distal end opening 30, the stress load is released, and the stent 2 expands and restores its original shape.
[0046]
As shown in FIG. 1 or FIG. 6, a Y-type connector 33 is attached to the proximal end of the sheath 3 having the rear end opening via a connector 32. The instrument for treating a stenosis in a body cavity includes fixing means (fixing mechanism, lock mechanism) for releasably fixing the sheath to the catheter. Specifically, an adapter 34 is attached to the rear end of the Y-type connector 33. 34 Turn clockwise to insert a balloon catheter through the inside 5 The adapter 34 is fixed to the outer tube 52, so that the balloon catheter 5 cannot be slid in the axial direction and is locked. When the adapter 34 is rotated counterclockwise, the lock is released, and the relative position of the sheath 3 and the balloon catheter 5 in the axial direction can be changed. As described above, the instrument for treating a stenosis in a body cavity of the present invention has a lock mechanism for fixing the sheath and the balloon catheter.By operating either the sheath or the balloon catheter in the fixed state, Both can be easily inserted or withdrawn into the body cavity, preventing the stent from being released at unexpected locations. Further, since the lock mechanism has an unlocking mechanism, the relative positional relationship between the sheath and the balloon catheter can be changed when necessary, so that the stent can be released.
You.
[0047]
Specifically, in this embodiment, as shown in FIG. 6, the adapter 34 is formed in a cylindrical body, and the inner surface is formed in a tapered surface whose diameter is reduced toward the rear end. Further, a first screw portion 34a is formed on the tapered surface. The rear end of the Y-shaped connector 33 is formed of a plurality of slits 33a extending in the axial direction. A second screw portion 33b screwed to the first screw portion 34a is formed on an outer surface of the slit 33a. ing. Then, when the adapter 34 is rotated clockwise, the first screw portion 34a and the second screw portion 33b are screwed together, the gap between the slits 33a is reduced, and the slit 33a is connected to the outer tube of the balloon catheter 5. The outer surface of 52 is pressed to enter the locked state. On the other hand, when the adapter 34 is rotated counterclockwise, the screw engagement between the first screw portion 34a and the second screw portion 33b is released, the gap between the slits 33a is widened, the locked state is released, and the balloon catheter 5 is released. Can move in the sheath 3 in the axial direction.
[0048]
The lock mechanism is not limited to the above structure. For example, conversely, a tapered surface that expands in the rear end direction is formed on the inner surface of the rear end of the Y-type connector 33, and a first threaded portion is formed on the tapered surface, and the other end of the connector 34 extends in the axial direction. A plurality of slits are formed, and a second screwing portion 3 screwed to the first screwing portion is formed on an outer surface thereof. Then, the one end of the adapter 34 may be inserted into the rear end of the Y-type connector 33 and locked by rotating.
In addition, it is preferable that a valve body 35 for maintaining liquid tightness between the sheath 3 and the balloon catheter 5 is provided in the Y-type connector 33.
[0049]
It is preferable that an X-ray contrast part 12 is formed on the outer surface of the sheath 3. In this embodiment, as shown in FIG. 2, an imaging portion 12 is formed on a rear outer surface of a portion where the stent 2 is stored. Thereby, the position of the sheath 3 can be accurately grasped under X-rays. Further, if the projecting portion 6 described later is formed of an X-ray opaque material, the relative positions of the sheath 3 and the balloon catheter 5 can be increased. The position can be confirmed, and the procedure becomes easier. The portion where the X-ray contrast part 12 is formed may be near the protruding part 6 as in this embodiment, but may be at the tip of the sheath 3. Thereby, in the former, the procedure can be performed while confirming that the X-ray contrast part 12 is separated from the protruding part 6, whereas in the latter, the X-ray contrast part 12 approaches the protruding part 6 and approaches. You can perform the procedure while confirming that you will go.
[0050]
As a method of forming the X-ray contrast part, a metal of an X-ray opaque material (for example, gold, platinum, a platinum-iridium alloy, silver, stainless steel, platinum, or an alloy thereof) is used to form the X-ray contrast part 12. It is conceivable that the sheath is fitted to a portion to be inserted or is embedded in the outer surface or the inner surface of the sheath. Further, it is preferable that the outer surface or the inner surface of the sheath be a continuous surface having no level difference in a state where the X-ray contrast part 12 is provided.
[0051]
The outer diameter of the sheath 3 is 1.16 to 4.2 mm, preferably 1.3 to 3.8 mm, and the inner diameter is 1.0 to 3.2 mm, preferably 1.1 to 3.0 mm. The thickness is 0.08 to 0.50 mm, preferably 0.10 to 0.3 mm. In this embodiment, the outer diameter is 1.7 mm, the inner diameter is 1.46 mm, and the wall thickness is 0.12 mm.
[0052]
As a material for forming the sheath 3, a thermoplastic elastomer is preferable in consideration of physical properties (flexibility, hardness, strength, kink resistance, stretchability) required for the sheath, and nylon, urethane, polyester, and olefin are preferable. It is appropriately selected from the systems, more preferably a urethane system.
Further, the outer surface of the sheath 3 is preferably subjected to a treatment for providing lubrication. As such a treatment, for example, hydrophilic polymers such as poly (2-hydroxyethyl methacrylate), polyhydroxyethyl acrylate, hydroxypropyl cellulose, methyl vinyl ether maleic anhydride copolymer, polyethylene glycol, polyacrylamide, and polyvinylpyrrolidone are used. Examples of the method include coating or fixing. Further, the above-mentioned material may be coated or fixed on the inner surface of the sheath 3 in order to improve the slidability with the balloon catheter 5.
[0053]
Next, another embodiment of the instrument for treating stenosis in a body cavity of the present invention will be described with reference to FIG.
The difference between this embodiment and the instrument 1 for treating a stenosis in a body cavity described above is that the balloon catheter 5 of the instrument 31 for treating a stenosis in a body cavity of the embodiment is located behind the balloon 4 and in front of the sheath 3. Only the point of having the balloon protection means 14 is the same in other respects. The same parts are denoted by the same reference numerals.
[0054]
Since the treatment instrument 31 of this embodiment has such balloon protection means 14, even if only the balloon catheter 5 is moved toward the rear end, the balloon protection means 14 comes into contact with the distal end surface of the sheath 3. The balloon 4 does not enter the sheath 3. Therefore, the balloon 4 is not damaged by the sheath 3 or the stent 2.
[0055]
Specifically, the balloon protection means 14 of this embodiment is formed in an annular projection having an outer diameter larger than the inner diameter of the sheath 3. Preferably, the balloon protection means has an outer diameter smaller than the outer diameter of the sheath. The balloon protection means may be provided integrally with the outer tube of the balloon catheter. Further, the balloon protection means may be formed of an X-ray opaque material. Further, the balloon protection means may be a projection provided on the outer tube of the balloon catheter. The projection may be plural.
[0056]
Next, a method of using the instrument for treating a stenosis in a body cavity of the present invention will be described with reference to FIGS.
First, as shown in FIG. 8A, a guide wire 90 is inserted through the first opening 59 of the branch hub 80 and passes through the stenosis according to a conventional method. Next, the intracorporeal treatment instrument 1 of the present invention is advanced along the guide wire to a position near the stenosis portion 95 in the body cavity 96. The position of the stenosis is confirmed by X-ray contrast by injecting a contrast agent from a guiding catheter (not shown) connected to the opening of the body cavity (for example, the opening of the coronary artery).
[0057]
Then, as shown in FIG. 8 (b), the treatment instrument 1 is advanced further forward, and after the balloon 4 is positioned at the stenosis part 95, a balloon inflation fluid flows in from the second opening 51 and the balloon 4 To expand. As a result, the blood vessel may not expand depending on the pathological type of the lesion, but may expand by about 90%. As described above, in the device for treating a stenosis in a body cavity according to the present invention, the stenosis can be expanded to some extent by inflating the balloon at the stenosis before placing the stent. The position of the balloon 4 is confirmed by the X-ray contrast unit 9.
[0058]
Next, once the balloon 4 is deflated, the treatment instrument 1 is further advanced forward, and as shown in FIG. 9A, the vicinity of the distal end of the sheath 3 holding the stent 2 is placed inside the stenosis portion 95. Position. This positioning is performed while confirming the projection 6 formed of the radiopaque material by X-ray contrast. Then, the balloon 4 is expanded and fixed in the body cavity 96 as shown in FIG. As described above, the device for treating a stenosis in a body cavity of the present invention can fix the position even in a thin and severely bent blood vessel such as a coronary artery by inflating the balloon on the central side (front) of the stenosis. Therefore, the self-expandable stent can be accurately placed at the target site.
[0059]
Further, the adapter 34 provided on the Y-type connector 33 is rotated counterclockwise to release the locked state between the sheath 3 and the balloon catheter 5, and then the sheath 3 is moved in the axial rear end direction. By releasing the lock, only the sheath 3 can be moved rearward. Therefore, when only the sheath is moved, the stent 2 held in the sheath 3 comes into contact with the protruding portion 6 provided on the balloon catheter 5, and the distal end of the sheath 3 Discharge from the opening 30. This state is shown in FIG. The relative positional relationship between the sheath 3 and the balloon catheter 5 is confirmed by X-ray contrast between the X-ray contrast part 12 of the sheath 3 and the protruding part 6 formed of a radiopaque material.
Finally, as shown in FIG. 10 (b), after the balloon 4 is deflated, the procedure is completed by moving the sheath 3 and the balloon catheter 5 toward the rear end and removing them from the body cavity 96.
[0060]
【The invention's effect】
The instrument for treating a stenosis part in a body cavity of the present invention is formed in a substantially cylindrical shape, the outer diameter is compressed when inserted into a living body, and the outer diameter expands when the body is placed in a living body, and the stent is restored to its original shape. A balloon catheter having a balloon that is inserted into the stent and the sheath and has a balloon at a site protruding from the distal end of the sheath and the stent. Has a protruding portion that comes into contact with the stent at the time of movement toward the rear end of the sheath, behind the portion where the stent is stored, and that discharges the stent from the distal end of the sheath. The self-expandable stent can be accurately and easily positioned on the target site even in a thin and highly curved blood vessel such as a coronary artery with a simple structure. It can be placed.
[0061]
And if the protrusion is an annular protrusion having an outer diameter smaller than the inner diameter of the sheath and larger than the inner diameter of the compressed stent, the protrusion does not hinder the movement of the sheath in the axial direction, Since the sheath is annular, it reliably contacts the stent when the sheath is moved forward, so that the stent can be reliably released.
Furthermore, if the protruding portion is formed of an X-ray contrast material, the position of the stent can be accurately grasped under X-ray contrast, and the procedure becomes easier.
[0062]
In addition, if the instrument for treating a stenosis in a body cavity has a fixing means for releasably fixing the sheath to the balloon catheter, by operating either the sheath or the balloon catheter in the fixed state, both can be placed in the body cavity. The stent or balloon catheter can be easily inserted or withdrawn to prevent release of the stent at unintended locations and, in the released state, can change the relative position of the sheath or balloon catheter, thereby Can be released.
[Brief description of the drawings]
FIG. 1 is a front view of one embodiment of a device for treating a stenosis in a body cavity of the present invention.
FIG. 2 is a schematic view of the vicinity of the distal end of the instrument for treating a stenosis in a body cavity shown in FIG. 1;
FIG. 3 is a partially enlarged sectional view of FIG. 2;
FIG. 4 is a perspective view of one embodiment of a stent for indwelling in a body cavity which constitutes the instrument for treating a stenosis in a body cavity of the present invention.
FIG. 5 is a perspective view of another embodiment of a stent for indwelling in a body cavity which constitutes the device for treating a stenosis in a body cavity of the present invention.
FIG. 6 is a cross-sectional view showing the vicinity of a Y-shaped connector of a sheath constituting the instrument for treating a stenosis in a body cavity of the present invention.
FIG. 7 is a cross-sectional view of the vicinity of a branch hub of a balloon catheter constituting the device for treating a stenosis in a body cavity of the present invention.
FIG. 8 is a schematic cross-sectional view for explaining the operation of the instrument for treating a stenosis in a body cavity of the present invention.
FIG. 9 is a schematic sectional view for explaining the operation of the instrument for treating a stenosis in a body cavity of the present invention.
FIG. 10 is a schematic sectional view for explaining the operation of the instrument for treating a stenosis in a body cavity of the present invention.
FIG. 11 is a sectional view of the vicinity of the distal end of another embodiment of the device for treating a stenosis in a body cavity of the present invention.
FIG. 12 is a cross-sectional view of a conventional instrument for treating a stenosis in a body cavity.
[Explanation of symbols]
1 Instrument for treating stenosis in body cavity
2 Stent for indwelling in body cavity
3 sheath
4 balloon
5 balloon catheter
6 Projection

Claims (4)

A stent for indwelling in a body cavity, which is formed in a substantially cylindrical shape, and whose outer diameter is compressed when inserted into a living body and whose outer diameter is expanded and restored to its original shape during indwelling in a living body, and a state where the outer diameter of the stent is compressed And a balloon catheter having a balloon inserted into the sheath and the distal end of the stent. The balloon catheter contains the stent. Backward from the site, when the sheath comes into contact with the stent when moving in the rear end direction, a protrusion for discharging the stent from the front end of the sheath, and when only the balloon catheter is moved in the rear end direction in, that the sheath of the front end surface in contact, and a balloon protection means for inhibiting the entry into the sheath of said balloon Vivo stenosis treatment device according to symptoms. The device for treating a stenosis in a body cavity according to claim 1, wherein the protrusion is an annular protrusion having an outer diameter smaller than the inner diameter of the sheath and larger than the inner diameter of the compressed stent. The device for treating a stenosis in a body cavity according to claim 1, wherein the protruding portion is formed of an X-ray opaque material. The instrument for treating a stenosis in a body cavity according to any one of claims 1 to 3, wherein the instrument for treating a stenosis in a body cavity has fixing means for releasably fixing the sheath to the balloon catheter.

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