JP2006136382A - Catheter for self-expandable stent delivery, stent delivery assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stent delivery assembly capable of mounting a stent keeping a small bore to place a stent in a fine blood vessel. <P>SOLUTION: The new stent delivery assembly equipped with a first linear structure at the distal end of a catheter and a second linear structure which has a very fine diameter and is wound around the outer periphery of the self-expandable stent attached to the first linear structure is provided. Since the distal end of the second linear structure is fixed on the first linear structure by a soluble resin, the self-expansion of the stent is prevented, and the stent is released and is expanded by itself by dissolving the soluble resin when electric or heat energy is applied. Since the stent delivery assembly never uses any balloons and sheathes, the diameter is made to be identical to the diameter of the stent when the stent is mounted. Consequently, the stent is delivered to narrower blood vessels, and injuries to blood vessel walls in the passage to an affected area are prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stent (intraluminal graft) delivery catheter and stent delivery assembly that are widely used as minimally invasive therapy.

  The primary stent is an intraluminal graft that is carried through a lumen such as a blood vessel and supported by an action from the inside by expanding its diameter at the treatment site of the lumen. It was developed to solve acute coronary occlusion and re-stenosis (so-called restenosis) at the site of PTCA, which were problems of percutaneous transluminal coronary angioplasty (PTCA).

  However, while stents are widely used in the above-mentioned coronary arteries, in recent years, the same percutaneous transluminal minimally invasive therapy has been applied to the treatment of aneurysm closure by a stained graft. It is also widely used as a very good treatment that can reliably close the aneurysm.

  In addition to the diversified deployment of such cases, self-expanding stents that are housed in sheaths called self-expanding stents and expanded from the sheath at the affected area and biodegradable polymers impregnated with drugs Various advances have been made, such as drug-eluting stents, where a drug is coated on a stent and the drug is gradually released at the site of placement.

  However, these stent delivery methods include only a balloon expansion method in which a balloon catheter is mounted and the balloon is expanded at the affected part, and a self-expanding method by being accommodated in the sheet catheter and released from the sheet at the affected part. There is no significant progress in the delivery method itself.

  In the conventional method of mounting on a balloon, the outer diameter of the balloon catheter corresponds to the inner diameter of the stent, and therefore cannot be made smaller than the outer diameter of the catheter. In addition, there is a limit to reducing the diameter of a balloon catheter in order to give strength sufficient to withstand the expansion pressure of the stent.

  On the other hand, since the sheet-type catheter accommodates the stent body in the sheet, it is necessary to use a sheath whose inner diameter is larger than the outer diameter of the stent. Naturally, the sheet stent is thicker than the balloon catheter because it is thicker than the outer diameter of the stent. A combination of a self-expanding stent and a sheath catheter has been reported in JP 2000-517223.

Special Table 2000-517223

  Thus, in a situation where the diameter of the catheter cannot be reduced, it is difficult to reach the back of the stent inside the skull, and the target of stent therapy is limited to the lesion blood vessels outside the skull. The present invention has been accomplished as a result of diligent examination in view of such problems, and according to the stent delivery assembly of the present invention that has achieved a narrow aperture, blood vessels within the reach of the microcatheter including subarachnoid blood vessels can be treated. It provides a very meaningful minimally invasive therapy that is of interest.

  In order to solve the above-mentioned problems, the present invention is a catheter for delivering a self-expanding stent, wherein the first wire structure has a diameter of 0.01 mm to 5.0 mm and a length of 0.5 mm to 50 mm. Is attached to a substantially central portion of the distal end of the catheter in the direction of the long axis of the catheter, and the second wire having a diameter of 0.005 mm to 0.1 mm is attached to the substantially distal end portion of the catheter or the first wire structure. The present invention provides a self-expanding stent delivery catheter to which a structure is attached.

  Furthermore, the present invention relates to the self-expanding stent delivery catheter, wherein the second wire structure is wrapped around an outer peripheral portion of a self-expanding stent attached to be inserted into the first wire structure. Thus, the expansion of the stent at a temperature higher than the transformation point temperature of the stent is suppressed, and the end portion of the second wire structure wound so as to surround the stent is A stent delivery assembly arranged to be fixed or sacrificially bonded to a thin wire structure is provided.

  According to the present invention, a first wire structure is disposed at the distal end of a catheter, and a second wire structure having an extremely small diameter is wound around the outer periphery of a self-expanding stent attached thereto to suppress the self-expansion of the stent. A novel stent delivery assembly having a structure in which a distal end portion of a wire structure is fixed to a part of a microcatheter with a soluble resin is provided. Since the stent delivery assembly of the present invention does not use a balloon or a sheath, the diameter when the stent is mounted can be matched to the diameter of the stent as much as possible, and the stent can be delivered to a thinner blood vessel. Thus, damage to the blood vessel wall can be suppressed in the route to the affected area.

  As described above, the present invention provides a micro catheter for stent delivery to which a fine wire structure is added. The stent delivery microcatheter of the present invention has (1) a flexible and short first wire structure and (2) a second wire structure having high elasticity, high slidability, high strength, and an ultrafine diameter at its distal end. It consists of a structure that is arranged.

  Then, a self-expanding stent is mounted on the first wire structure, and the second wire structure is wound around the outer periphery of the self-expanding stent to suppress the self-expansion of the stent. And the stent delivery assembly of this invention is constructed | assembled by arrange | positioning so that the front-end | tip of a 2nd wire structure may be fixed or sacrificial joined to a part of 1st wire structure or the substantially front-end | tip part of a catheter with soluble resin. . When the soluble resin is dissolved after positioning the stent in this stent delivery assembly, the restriction of the stent expansion due to the binding of the second wire structure is released, and the stent is self-expanding. The second wire structure is highly slidable and is removed by sliding along the interface between the stent and the blood vessel wall that is self-expanding as the catheter is removed. Here, “sacrificial bonding” means bonding that is bonded before use, but has an effect by being cut later. The material used for the sacrificial bonding and the method for cutting the joint portion of the sacrificial bonding will be described in detail later.

  The material of the catheter used in the present invention is not particularly limited, and a catheter of a material generally used in the current medical field can be appropriately used for the purpose of the present invention. Examples of suitable catheter materials include polypropylene, polyacetal, polyethylene, polyester, polycarbonate, polyurethane, polyamide, ethylene-butylene-styrene block copolymer, polystyrene, butadiene-isoprene composition, polyvinyl chloride, thermoplastic rubber. Examples thereof include, but are not limited to, silicone resins, polycarbonate copolymers, and ethylene-vinyl acetate copolymers.

  The first wire structure is attached to the distal end portion of the catheter. The material of the first wire structure is not particularly limited, but examples of suitable materials include titanium, platinum, gold, tungsten, and alloys thereof, as well as fluorine resin, polyolefin, polyamide, polyimide, polyurethane, and silicone resin. However, it is not limited to them. In order to achieve smooth insertion into the body, the first wire structure is preferably sufficiently flexible to follow the flexibility of the stent. The diameter of the first wire structure of the present invention is preferably 0.01 mm to 5.0 mm. Moreover, the length becomes like this. Preferably it is 0.5 mm-50 mm. However, the diameter and length of the first wire structure are not limited within the range. The first wire structure may be the catheter itself, and such an embodiment is also within the scope of the present invention.

  Further, an extra fine second wire structure is attached to the substantially distal end portion of the catheter or the first wire structure. The material of the second line structure is not particularly limited, but may be anything as long as it is rigid without being limited to metal. Examples of suitable materials for the second line structure include aromatic polyamide, aromatic polyimide, aromatic polyester, polypropylene, polystyrene, acrylic resin, melanin resin, PEEK resin, fluororesin, and a rigid alloy. It can be mentioned, but is not limited to them. In order to prevent the outer diameter from becoming larger than that of the catheter after being wound around the stent, the second wire structure needs to be extremely fine, and its diameter is preferably 0.005 to 0.1 mm. It is not necessarily limited within the range. The second wire structure is highly slidable on the surface, and it is necessary that the inner wall of the blood vessel is not damaged when the catheter is removed and the stent is placed.

  This can be achieved by following the general guide wire surface treatment technology. The surface treatment technology is not limited to this, but when made of a metal material, a coating with a resin such as polyolefin, polyvinyl chloride, polyester, polyamide, polyurethane, polystyrene, fluororesin, or silicone rubber is employed. be able to.

  More specifically, such surface treatment can be achieved by immersing and drying the fine wire structure in a resin solution obtained by dissolving these resins in a solvent. Further, the surface of the resin film is treated with a compound having a chemically active functional group, such as a compound having an isothiocyanate group or an aminosilane coupling agent, and the introduced functional group is used as a scaffold such as polyethylene glycol. It is also possible to bind a hydrophilic polymer. Examples of the hydrophilic polymer that can be used here include, but are not limited to, polyvinyl pyrrolidone, vinyl acetate, hydroxyalkyl (meth) acrylate acid, alkyl cellulose, and hyaluronic acid. It is also possible to fix the hydrophilic polymer on the surface of the resin coating by creating radical active sites by low temperature plasma initiated graft polymerization or the like and bringing the monomer into contact therewith. Examples of the monomer used here include, but are not limited to, hydroxyalkyl (meth) acrylate and N-alkylacrylamide.

  In the present invention, the outer peripheral portion of the self-expanding stent attached to the first wire structure can be surrounded so as to wind the second wire structure. In order to enable sufficiently strong winding, the second wire structure needs to have high elasticity and high strength. By performing such winding, the expansion of the stent at a temperature higher than the transformation point temperature of the stent is suppressed. Preferably, the winding pattern of the second wire structure is optimized so that the self-expanding stent can be mounted with the second wire structure as short as possible, i.e. with a small number of turns. Mounting with a small number of turns reduces the friction and physical load that slides and moves on the interface between the vessel wall and the outer peripheral surface of the stent when the elongated first thin wire structure is removed together with the catheter. This is because the load on the blood vessel wall when the self-expanding stent placement is completed and the catheter is removed is reduced.

  When the soluble material is melted by the application of electrical or thermal energy, the sacrificial joint between the first wire structure and the second wire structure is cut, thereby wrapping the second wire structure to surround the stent. The body releases and the self-expanding stent self-expands. The electric or thermal energy applied here needs to be in a range that does not adversely affect the living body into which the stent is inserted.

  Two leads for applying electricity can be used to cut the sacrificial joint with such electrical energy. These two lead wires are both embedded in the catheter so that they do not come into contact with blood, and a terminal for connecting to the electrode is arranged on the external side of the catheter (the side not inserted into the body). You can also. One lead wire is connected to the second wire structure, and the other lead wire is connected to the sacrificial joint. The second wire structure is in contact with blood, but the portion is covered with resin to provide insulation. In addition, it is preferable to minimize the exposure of the lead wire in the sacrificial joint, and only the sacrificial joint is exposed to blood, or the slightly exposed lead wire is covered with an insulator.

  Examples of resins that can be used as such insulators include, but are not limited to, polyolefins, polyurethanes, fluororesins, and the like. The electric energy applied during electrolysis is preferably 0.1 to 2.0 mA in terms of current value and 0.1 to 2.0 V in terms of voltage value, but is not limited thereto. In consideration of the time required for electrolysis, leakage in blood, and influence on the living body, it is possible to apply electric energy in other ranges. The application of such current causes corrosion of the sacrificial joint, and the sacrificial joint is cut. Although the sacrificial joint is exposed in the blood, corrosion of the sacrificial joint and the first wire structure occurs in the presence of blood. In the present invention, since the sacrificial joint needs to be cut, the sacrificial joint needs to be preferentially corroded as compared with the first line structure.

  Therefore, by using a metal material that has a lower ionization tendency than the first wire structure and has less influence on the living body than the first wire structure, and a noble metal is used for the lead wire. Electrolytic cutting can be achieved and the use of such materials for sacrificial joint welds and leads is a preferred aspect of the present invention. More specifically, examples of suitable metal materials used for the sacrificial joint include magnesium, aluminum, and iron, and noble metals used for the lead wires include tungsten, platinum, gold, silver, copper, and titanium. Nickel, and alloys thereof, but are not limited to these materials. A technique for cutting such a sacrificial joint by electrolysis is described in US Pat. No. 5,122,136.

  In the stent delivery catheter of the present invention, the placement of the stent can be assisted as a cylindrical sleeve structure having a diameter larger than the outer diameter of the stent using the catheter tip, and the structure with the catheter tip is applied. It is a preferred embodiment in the present invention.

  In the stent delivery catheter of the above aspect, one end of the stent can be inserted into the sheath-like structure portion arranged at the distal end portion of the catheter. Here, the sheath-like structure means a protruding structure in which the inner diameter of the catheter is wide at the distal end of the catheter, and when viewed from the cross section, the distal end of the catheter in this aspect is also in a concave recess. It has a similar form. The sheath-like structure preferably has an inner diameter of 0.5 to 4.5 mm, an outer diameter of 0.6 to 4.6 mm, and a length of 1 to 10 mm, but the size is particularly limited is not. By adopting such a structure, the stent delivery assembly of the present invention can flexibly cope with a place where the blood vessel is twisted, and smoothly conveys the stent without damaging the blood vessel due to the rigidity of the exposed stent. It becomes possible to do.

  Furthermore, although an Example and a figure are given and this invention is demonstrated further more concretely, this invention is not limited to them.

  The stent delivery catheter of the present invention is manufactured by attaching the first wire structure 2 to the central portion of the distal end of the catheter 1 to be inserted, and further welding the second wire structure 3 to the substantially distal portion of the catheter 1. (FIG. 1). Moreover, the aspect which welded the 2nd line structure 3 in the middle of the 1st line structure is also possible in this invention (FIG. 2). A self-expanding stent 4 to be inserted into the first wire structure 2 of the stent delivery catheter of FIG. 1 is mounted (FIG. 3), and the second wire structure 3 is wound around the mounted self-expanding stent 4. The self-expanding stent 4 is tightened (FIG. 4). By being tightened in this manner, the self-expansion of the stent 4 is suppressed. And the front-end | tip part of a 2nd line structure is sacrificially joined to a 1st line structure with a soluble material (sacrificial junction part 5), and the state where the self-expansion of the stent 4 was suppressed is maintained (FIG. 5) The stent delivery assembly of the present invention is produced.

  The catheter 1 having the stent delivery assembly of the present invention produced as described above is inserted from a blood vessel of, for example, a lower limb of a rat or mouse, and finally guided to the affected part (FIG. 6). When the thin wire structure is inserted as it is, a microcatheter used for the purpose of protecting the blood vessel from electric current or heat is further inserted to the front of the stent. In general, since the catheter to which the fine wire structure is attached performs this function, it is usually unnecessary to perform this operation separately. Then, by applying an electric current or heat, the second wire structure 3 that has been wound is released when the joint portion that has fixed the tip portion of the second wire structure with the sacrificial joint portion 5 is dissolved. Then, the suppression of the self-expanding stent 4 is released, and the stent 4 self-expands in the affected area (FIG. 7). Thereafter, when the stent delivery assembly is removed, only the self-expanding stent 4 remains, and the object of the present invention is achieved to expand in the affected area.

  Further, as described above, it is also possible to adopt a mode in which the sheath-like structure portion 6 having a concave shape is disposed at the distal end portion of the catheter 1 and one end of the stent 4 is inserted into the sheath-like structure portion 6. Yes (Fig. 8). FIG. 9 is a cross-sectional view thereof. As described above, in this embodiment, since the stent 4 is inserted into the sheath-like structure portion 6 at the distal end portion of the catheter, the blood vessel is hardly damaged and the catheter can be inserted.

  Since the stent delivery assembly of the present invention does not use a balloon or a sheath, the diameter when the stent is mounted can be matched to the diameter of the stent as much as possible, and the stent can be delivered to a thinner blood vessel. Thus, damage to the blood vessel wall can be suppressed in the route to the affected area. Therefore, since the delivery system of the stent of the present invention can be applied to patients who could not be treated with a stent until now, it is considered that the application range of the stent is newly expanded. It is done.

FIG. 1 is a view showing a structure of a stent delivery catheter of the present invention in a mode in which a second wire structure is welded to a substantially distal end portion of a catheter. FIG. 2 is a view showing the structure of the stent delivery catheter of the present invention in a mode in which the second line structure is welded in the middle of the first line structure. FIG. 3 is a view showing a state where a self-expanding stent is mounted on the stent delivery catheter of the present invention. FIG. 4 is a view showing a state in which the second wire structure is wound around the self-expanding stent and the self-expanding stent is tightened. FIG. 5 is a view showing the stent delivery assembly of the present invention in a state where the tip portion of the second wire structure is fixed with a polymer which is a soluble material. FIG. 6 is a view showing a state where a catheter having the stent delivery assembly of the present invention is guided to an affected area. FIG. 7 is a view showing a state where the wound second wire structure is released and the restraint of the stent is released. FIG. 8 is a view showing a state where the sheath-like structure portion 6 is arranged at the distal end portion of the catheter and one end of the stent 4 is inserted. FIG. 9 is a cross-sectional view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Catheter 2 1st wire structure 3 2nd wire structure 4 Stent 5 Sacrificial junction 6 Sheath-like structure

Claims (12)

A catheter for delivering a self-expanding stent, wherein a first wire structure is mounted in a substantially central portion of the distal end of the catheter in the direction of extension of the long axis of the catheter, and is further attached to a substantially distal end portion of the catheter. A self-expanding stent delivery catheter equipped with a two-wire structure. The first wire structure has a diameter of 0.01 mm to 5.0 mm and a length of 0.5 mm to 50 mm, and the second wire structure has a diameter of 0.005 mm to 0.1 mm. The self-expanding stent delivery catheter as described. A catheter for delivering a self-expanding stent, wherein a first wire structure is attached to a substantially central portion of the distal end of the catheter in a direction of extending the long axis of the catheter, and the first wire structure is further attached to the first wire structure. A self-expanding stent delivery catheter equipped with a two-wire structure. The first wire structure has a diameter of 0.01 mm to 5.0 mm and a length of 0.5 mm to 50 mm, and the second wire structure has a diameter of 0.005 mm to 0.1 mm. The self-expanding stent delivery catheter as described. The catheter material is polypropylene, polyacetal, polyethylene, polyester, polycarbonate, polyurethane, polyamide, ethylene-butylene-styrene block copolymer, polystyrene, butadiene-isoprene composition, polyvinyl chloride, thermoplastic rubber, silicone resin, polycarbonate. The self-expanding stent delivery catheter according to any one of claims 1 to 4, wherein the catheter is selected from the group consisting of a copolymer and an ethylene-vinyl acetate copolymer. The material of the first wire structure is selected from the group consisting of titanium, platinum, gold, tungsten, and alloys thereof, and fluororesin, polyolefin, polyamide, polyimide, polyurethane, and silicone resin. The self-expanding stent delivery catheter according to any one of claims 1 to 4. The material of the second line structure is selected from the group consisting of aromatic polyamide, aromatic polyimide, aromatic polyester, polypropylene, polystyrene, acrylic resin, melanin resin, PEEK resin, fluororesin and rigid alloy The self-expanding stent delivery catheter according to any one of claims 1 to 4, wherein the catheter is self-expanding. The said catheter front-end | tip part is a cylindrical sleeve structure which has an internal diameter larger than the outer diameter of the said self-expanding stent, The Claim 1 characterized by the above-mentioned. Self-expanding stent delivery catheter. 9. The self-expanding stent delivery catheter according to any one of claims 1 to 8, wherein the second is provided on an outer peripheral portion of a self-expanding stent mounted to be inserted into the first wire structure. By encircling the wire structure so as to be wound, expansion of the stent at a temperature higher than the transformation point temperature of the stent is suppressed, and the second wire structure wound so as to surround the stent. A stent delivery assembly in which a distal end portion of the first thin wire structure is fixed or sacrifice-bonded to the first fine wire structure. The stent delivery assembly according to claim 9, wherein a joint portion of the fixed or sacrificial joint is cut by decomposition with electric energy or thermal energy. The stent delivery assembly according to claim 9, wherein a sheath-like structure portion is disposed at a distal end portion of the catheter, and one end of the stent is inserted into the sheath-like structure portion. The stent delivery assembly according to claim 11, wherein the sheath-like structure portion has an inner diameter of 0.5 to 4.5 mm, an outer diameter of 0.6 to 4.6 mm, and a length of 1 to 10 mm.

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