Catheter for delivery

Abstract

To provide a catheter for delivery having a new structure, the catheter making it possible to perform delivery and detention of a stent and the like to a blood vessel and the like using simple equipment and easy operation without requiring an expansion balloon as before.SOLUTION: A catheter for delivery includes: a holding part 16 having a self-expanding type skeletal structure on the distal end side of a shaft part 12 to be inserted into a lumen; and an outer cylinder member 24 that covers the holding part 16 to hold it in a contraction state and exposes the holding part 16 to permit its deformation into an expanded state. By externally inserting an expandable detention object 28 such as a stent to the holding part 16 and performing coverage using the outer cylinder member 24, the expandable detention object 28 can be held in a contraction state, and by exposing the holding part 16 from the outer cylinder member 24, expansion force can be applied from the holding part 16 to the expandable detention object 28.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a delivery catheter used when inserting an expandable indwelling device such as a stent into a human body lumen such as a blood vessel. [Background technology]

[0002] Conventionally, expandable implantable devices such as stents that are placed in human body lumens have been used for treating stenosis in human body lumens such as blood vessels. After being delivered to a predetermined site in the human body lumen, such expandable implantable devices are placed in the human body lumen in an expanded state.

[0003] Incidentally, when delivering a stent or the like to a blood vessel, a balloon catheter has been used conventionally for minimally invasive treatment. That is, the stent is positioned and supported in an externally inserted state by a wound balloon and inserted into the blood vessel, whereby the stent is delivered to the site of the intended treatment.

[0004] However, with a balloon catheter, the outer diameter is relatively large even in a wound state, and when a stent is fitted onto it, the outer diameter at the time of delivery becomes large, making the delivery operation difficult and limiting the areas where it can be applied.

[0005] In addition, depending on the material and type of the expandable indwelling device, it may be difficult to reliably maintain the expandable indwelling device in a contracted state until delivery is complete, and therefore it may be necessary to cover the expandable indwelling device with an external tubular member to maintain the expandable indwelling device in a contracted state, which may result in an even larger outer diameter. For example, in stents made of biodegradable materials that have been considered in recent years, not only is the material thickness of the stent itself greater than that of conventional metal stents, but the diameter is also relatively large even in the contracted state, which may further exacerbate the above-mentioned problems.

[0006] Furthermore, because the delivery of an expandable implant requires the manipulation of a balloon catheter, a control device including a special pressure source for supplying and discharging pressurized fluid to the balloon is required. In addition, the operation of these devices requires skill, which creates problems such as a heavy burden on equipment, labor, and ability. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2019-126519 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made against the background of the above-mentioned circumstances, and an object of the present invention is to provide a novel delivery catheter that enables the delivery and expansion of an expandable indwelling device to a human body lumen without the need for a stent expansion balloon. [Means for solving the problem]

[0009] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely illustrative and may be combined with one another as appropriate, and the multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0010] In a first embodiment, there is provided a delivery catheter used for delivery and placement into a lumen of a living body of an expandable device that is expanded and placed in the lumen of the living body, the delivery catheter having a shaft portion that is inserted into the lumen of the living body, and a holding portion having a self-expanding skeletal structure that is expandable and contractible is provided on the distal end side of the shaft portion, and an outer tubular member is arranged to be movable relative to the holding portion in the longitudinal direction, and covers the holding portion to hold the holding portion in a contracted state, and exposes the holding portion to allow the holding portion to deform to an expanded state. By inserting the expandable device over the holding portion and covering it with the outer tubular member, the expandable device can be held in a contracted state, and by exposing the holding portion from the outer tubular member, an expansion force can be applied from the holding portion to the expandable device.

[0011] According to this aspect, the holding part can be held in a contracted state by the outer tubular member, and can be expanded by exposing the holding part from the outer tubular member. Therefore, by inserting and supporting an expandable device onto the holding part and covering it with the outer tubular member, the expandable device can be delivered to a target site within a human body lumen in a contracted state, and then by exposing it from the outer tubular member, the expansion force of the holding part can be applied to the expandable device to expand it and place it in place.

[0012] Therefore, the delivery catheter according to this embodiment makes it possible to perform the delivery and expansion of the expandable indwelling device to a body lumen without the need for a stent expansion balloon. Therefore, in addition to not needing equipment, labor, or ability to expand and contract the balloon when performing a procedure using an expandable indwelling device, it is also easy to set the outer diameter of the holding part of the self-expanding skeletal structure in a contracted state to be smaller than that of a balloon, which has a relatively large diameter even in a wound state, and by reducing the outer diameter of the expandable indwelling device when delivered into a body lumen, it is possible to improve the ease of delivery, etc.

[0013] A second aspect is the delivery catheter according to the first aspect, wherein the holding portion has an open end shape that opens toward the distal end.

[0014] According to this aspect, by making the distal end of the holding portion an open end, the deformation constraint force of the holding portion can be reduced. For example, by increasing the amount of expansion and contraction deformation of the holding portion and, by extension, the expandable indwelling object, it is possible to reduce the diameter dimension in the contracted state while sufficiently ensuring the diameter dimension in the expanded state, thereby further improving delivery operability.

[0015] A third aspect is a delivery catheter according to the second aspect, wherein the holding portion has a straight portion which is approximately cylindrical in an expanded state, and a tip portion which is located at the tip side of the straight portion and has a smaller diameter toward the opening on the distal end side, and the expandable device is inserted and held on the straight portion.

[0016] According to this aspect, since the tip portion is reduced in diameter when the holding portion is in an expanded state, it is possible to reduce the risk of damage to the inner surface of the lumen by the tip portion of the holding portion in an expanded state. Note that the specific manner in which the diameter of the tip portion of the holding portion is reduced is not limited, and for example, the tip portion may be tapered so that the diameter gradually decreases toward the opening over a predetermined axial length, or the edge of the opening at the tip may be bent inwardly in a short region so as to be folded.

[0017] A fourth aspect is a delivery catheter described in any one of the first to third aspects, in which the expandable indwelling device is inserted over the holding portion and covered with the outer tube member, thereby being held in a contracted state and assembled.

[0018] According to this embodiment, the device is configured to include an expandable indwelling device, and the expandable indwelling device can be stably maintained in a contracted state with a small diameter by being covered with an external tubular member. Therefore, it becomes possible to set various materials and characteristics of the expandable indwelling device with a large degree of freedom, and for example, as described in the fifth embodiment below, it becomes possible to advantageously adopt an expandable indwelling device such as a stent made of a biodegradable material (e.g., biodegradable resin), and it becomes easy to deliver the expandable indwelling device to the target location while stably positioned at a predetermined position on the catheter.

[0019] A fifth aspect is the delivery catheter according to the fourth aspect, wherein the expandable indwelling device is made of a biodegradable material.

[0020] A sixth aspect is a delivery catheter according to the fourth or fifth aspect, wherein the expandable device has a skeletal structure, and the holding portion has a finer skeletal structure than the skeletal structure of the expandable device.

[0021] According to this embodiment, since both the expandable indwelling object and the holding part have an expandable skeletal structure, the amount of expansion / contraction deformation can be advantageously secured, and in particular, since the skeletal structure of the holding part is finer than the skeletal structure of the expandable indwelling object, the holding force and expansion force of the holding part can act more stably on the expandable indwelling object.

[0022] A seventh aspect is a delivery catheter according to any one of the first to sixth aspects, further comprising a heating means for heating the holding portion.

[0023] According to this embodiment, the temperature of the expandable implant can be adjusted by heating the implant via the holding section, etc. This makes it possible to improve the adhesion of the expandable implant to the inner surface of a living lumen, for example, and in the case of an expandable implant having a high physical recoil rate such as a resin stent, it is possible to improve the stability of the shape and dimensions by suppressing the rate of diameter reduction after expansion by heating the expandable implant in the expanded state.

[0024] The eighth aspect is a delivery catheter as described in the seventh aspect, wherein the holding portion is made of metal and the heat generated by the heating means is diffused over a wide area of ​​the holding portion by utilizing the thermal conductivity of the holding portion.

[0025] According to this aspect, by utilizing the heat transfer performance of the holding portion, it is easily possible to efficiently regulate the temperature of the expandable indwelling object over substantially the entirety. Effect of the Invention

[0026] In the delivery catheter according to the present invention, a retaining section having a self-expanding skeletal structure is employed to retain the expandable indwelling object, so that the external dimensions can be kept small even when the expandable indwelling object is retained in a contracted state by the outer tubular member and delivered, and the expandable indwelling object can be quickly expanded by exposing the retaining section that retains the expandable indwelling object from the outer tubular member. Furthermore, compared to the case where an expandable indwelling object is delivered using a conventional balloon, no equipment or operation for expanding or contracting the balloon is required, and the equipment and operation can be simplified. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is an explanatory diagram illustrating the overall structure of a delivery catheter according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a self-expanding skeletal structure that constitutes the delivery catheter shown in FIG. [Diagram 3] FIG. 3 is a side view of the self-expanding scaffold structure shown in FIG. [Figure 4] FIG. 3 is an axial elevational view of the self-expanding scaffold structure shown in FIG. [Diagram 5] FIG. 4 is a side view corresponding to FIG. 3, illustrating an alternative embodiment of a skeletal structure that can be used in the delivery catheter shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In order to clarify the present invention more specifically, embodiments of the present invention will be described in detail below with reference to the drawings.

[0029] 1 shows the overall schematic structure of a delivery catheter 10 according to a first embodiment of the present invention. This delivery catheter 10 is a medical device used for treatment of internal lumens of the human body, and can be used for treatment of delivering an expandable indwelling device such as a stent to a treatment site such as a partially stenosed site in a blood vessel and placing it in an expanded state.

[0030] The delivery catheter 10 of this embodiment includes a longitudinal catheter body 12, and a skeletal structure 14 that is expandable and contractible is provided on the distal end side of the catheter body 12 that is inserted into the body.

[0031] The catheter main body 12 constitutes a shaft portion that can be curved and deformed along a blood vessel, and may have a solid structure, but in this embodiment, it has a hollow structure with a lumen through which a guidewire can be inserted. When a guidewire lumen is provided, it is not limited to an over-the-wire type, and a rapid exchange type lumen structure may be adopted, or, for example, a tube with a guidewire lumen may be inserted inside the catheter main body 12, and by extending the distal end side of such a tube through the skeletal structure 14, it is possible to prevent the guidewire from getting caught on the skeletal structure 14.

[0032] The catheter body 12 can be formed with an outer diameter and length that can be set according to the treatment site where the skeletal structure 14 is delivered and placed, for example, with an outer diameter dimension in the range of 1 to 5 mm and a length in the range of 10 to 100 cm. The material of the catheter body 12 is not particularly limited, and it can be suitably formed of soft or elastomeric synthetic resin materials such as polypropylene, polyamide, polytetrafluoroethylene, fluorine-based resin, polyurethane, polyamide, etc. In addition, for the purpose of improving kink resistance, a reinforced resin structure reinforced with fibers such as short fibers or long fibers, linear bodies (including coil-shaped linear bodies extending helically in the length direction inside the catheter body 12), braids, etc. can also be appropriately adopted.

[0033] An appropriate hub is attached to the proximal end of the catheter body 12. The hub is a known type, generally made of a hard synthetic resin material, and is designed to be gripped and operated by the practitioner with the fingers. Such a hub has a through hole communicating with the lumen of the catheter body 12, and a guide wire can be inserted into and removed from the catheter body 12 through this through hole. The hub to be used is not limited, and various types of known hubs can be used depending on the required functions, such as a branched type or a type equipped with a luer lock.

[0034] A skeletal structure 14 is provided at the distal end of the catheter main body 12. This skeletal structure 14 has a self-expanding skeletal structure that is expandable and contractible. Specifically, as shown in Figures 2 to 4, for example, a cylindrical net-like skeleton that is expandable and contractible in the radial direction and has a porous peripheral wall shape as a whole is formed by continuously connecting easily deformable basic skeletons like a mesh of approximately diamond-shaped windows.

[0035] The skeletal structure 14 of this embodiment has a holding portion 16 that extends in a cylindrical shape with a substantially constant diameter dimension in a large-diameter expanded state, and the tip side of this holding portion 16 is a circular opening 18 that opens toward the tip in the axial direction. In addition, the base end side of the holding portion 16 is a cylindrical tapered portion 20 that gradually decreases in diameter toward the base end side in the axial direction, and a substantially cylindrical fitting portion 22 is integrally formed at the minimum diameter portion on the base end side of this tapered portion 20.

[0036] The fitting portion 22 is fixed to the distal end side of the catheter main body 12 by fitting inside and outside, gluing, or the like, so that the skeletal structure 14 is fixedly attached coaxially to the catheter main body 12. The fitting portion 22 of the skeletal structure 14 may be fixed to the tip of the distal end side of the catheter main body 12, or the distal end side of the catheter main body 12 may protrude into the skeletal structure 14 by a predetermined length, or may even reach the opening 18 of the skeletal structure 14, or the catheter main body 12 may protrude and extend further from the opening 18 of the skeletal structure 14 to the tip side.

[0037] Furthermore, the catheter main body 12 and the skeletal structure 14 may be partially fitted with X-ray impermeable markers as required. Known markers may be used as such markers, and the catheter main body 12 and the skeletal structure 14 may be made X-ray impermeable by mixing a contrast agent such as X-ray impermeable powder (e.g., barium sulfate, bismuth oxide, powdered tungsten, etc.) with the material forming the catheter main body 12, or by using a X-ray impermeable material as the material forming the skeletal structure 14. It is desirable that such a marker is attached to, for example, a portion of the skeletal structure 14 where a stent is to be mounted. However, a marker may be attached to the stent itself. Also, by attaching a marker to, for example, the tip of the skeletal structure 14, a good recognition effect by X-rays can be obtained, particularly in consideration of safety.

[0038] Furthermore, it is desirable that the skeletal structure 14 having the holding portion 16 and the tapered portion 20 as described above has a sufficiently large radial expansion / contraction deformation amount and elastic restoring force to the expanded state. Taking into consideration the required expansion force and expansion / contraction deformation amount, it is possible to adopt a highly elastic synthetic resin material such as elastomer, but it is preferably formed of a superelastic metal material such as a nickel-titanium alloy.

[0039] As a result, by applying an external force directed radially inward to restrain the skeletal structure 14, it is possible to deform the skeletal structure 14 so that the tip side narrows and is maintained in a small-diameter tubular shape, and by releasing the restraint caused by the external force, it is possible to restore the skeletal structure 14 to its initial expanded shape in which each diamond-shaped window that makes up the mesh is expanded as shown in Figures 2 to 4.

[0040] Here, in this embodiment, an outer tubular member 24 can be used as a member that applies an external force in a radially inward direction to the skeletal structure 14. This outer tubular member 24 is a cylindrical sleeve that can be inserted onto the skeletal structure 14, and is assembled so that the skeletal structure 14 can be inserted and removed by moving relative to the outer tubular member 24 in the axial direction.

[0041] The outer tube member 24 is not limited in terms of its specific material or structure, as long as it has the strength or rigidity required against an external force in the diameter expansion direction so that it can hold the skeletal structure 14 in a reduced diameter state by being inserted around the skeletal structure 14. For example, the outer tube member 24 can be made of a synthetic resin material, or can be reinforced with a metallic linear or braided body, or made of a synthetic resin material reinforced with inorganic fibers. In addition, the outer tube member 24 that covers the skeletal structure 14 may be provided with an X-ray opaque marker or a material mixed with a contrast agent to provide visibility under X-ray fluoroscopy.

[0042] Incidentally, the outer tube member 24 is operable from the proximal end side of the catheter main body 12 extending outside the body so that the skeletal structure 14 can be exposed from the outer tube member 24 when the distal end side of the catheter main body 12 is inserted into a blood vessel. Specifically, for example, the tubular outer tube member 24 is externally inserted onto the catheter main body 12 so as to be relatively movable in the axial direction, and is provided extending to the proximal end side of the catheter main body 12 so that the proximal end side of the outer tube member 24 exposed outside the body can be operated. Alternatively, for example, the outer tube member 24 is formed with a length sufficient to cover the skeletal structure 14 and is structured to include an operating wire or the like extending toward the base end side, so that the proximal end side of the operating wire extending outside the body along the catheter main body 12 can be operated.

[0043] It is preferable that the outer tubular member 24 thus constructed can be fixedly positioned relative to the catheter body 12 in the axial direction. This prevents the outer tubular member 24 from being externally disposed at a predetermined position relative to the catheter body 12 and from unintentionally moving relative to the catheter body 12, thereby exposing the skeletal structure 14. Such a positioning mechanism can be configured, for example, by releasably positioning the outer tubular member 24 or the operating wire extending outside the body along the catheter body 12 as described above, relative to the catheter body 12 or to a hub provided at the proximal end of the catheter body 12, using a screw structure, a concave-convex engagement structure, a fitting structure, or the like.

[0044] When a stent, which is a type of expandable indwelling device, is delivered to a blood vessel treatment site using the delivery catheter 10 of this embodiment having the above-described structure, a stent 26 is assembled as shown in Fig. 1. Specifically, the stent 26 is fitted onto the skeletal structure 14, and the delivery catheter 10 is constructed by assembling the stent 26 together with the skeletal structure 14 in a state in which the stent 26 is held in a reduced diameter state by the outer tubular member 24.

[0045] The stent 26 is placed on the skeletal structure 14 in an expanded state, and then inserted into the outer tubular member 24 together with the skeletal structure 14 to reduce its diameter, but since the proximal end side of the skeletal structure 14 is formed as the tapered portion 20, the outer tubular member 24 can be relatively easily inserted from the proximal end side. Alternatively, the stent 26 in a reduced diameter state may be inserted on the skeletal structure 14 in a reduced diameter state. Note that, for the purpose of improving the ease of inserting the outer tubular member 24, the axial end of the outer tubular member 24 may be tapered so that the diameter expands toward the opening side.

[0046] The specific shape, structure, material, etc. of the stent 26 are not particularly limited, but the stent 26 is arranged by extrapolating the skeletal structure 14 in a state where the outer diameter fits within the length range of the holding part 16, which has a substantially constant outer diameter, so that the expansion force of the skeletal structure 14 can be efficiently applied. The stent 26 is required to be able to be contracted together with the skeletal structure 14 to an outer diameter that does not interfere with delivery, and to be able to be expanded to an outer diameter required for the treatment of the blood vessel in which it is placed, and to have a characteristic of maintaining the expanded state or a characteristic of resisting an external force in the direction of contraction so that the stent 26 is stably retained at a predetermined site of the blood vessel. Considering a general blood vessel, it is preferable that the length dimension can be set within a range of 5 to 100 mm, the outer diameter in the contracted state can be set within a range of 1 to 5 mm, and the radial expansion ratio is within a range of 1.5 to 10 times.

[0047] The material of the stent 26 may be a shape-memory metal such as a nickel-titanium alloy, or a shape-memory polymer such as polynorbornene or trans-polyisoprene. The material of the stent 26 may be a biodegradable metal (Mg, Ca, Zn, Li, Fe, or the like), or a biodegradable polymer such as polylactic acid, polycaprolactone, or polyglycolic acid. The stent 26 made of various materials may be an integrally formed product by cutting out a cylindrical molded body with a laser or the like, or may be formed into a mesh structure in which a plurality of wires are braided or combined in a spiral shape, or may be formed into a composite structure in which an integrally formed product having a predetermined skeletal structure is combined with a wire.

[0048] The resin material as described above can be appropriately mixed or blended with a plurality of types of compositions, and can be realized by adjusting biodegradable properties and shape memory properties. In any case, the stent 26 made of a resin material can be suitably adopted in this embodiment. That is, the resin stent 26 tends to have a larger wall thickness than a metal stent in order to realize properties such as strength, but by adopting the delivery catheter 10 of this embodiment, it is easy to reduce the outer diameter dimension in the contracted state compared to a catheter equipped with a conventional balloon, and the problem of the wall thickness of the stent 26, which is likely to be a problem during delivery, can be reduced or eliminated.

[0049] Such a stent 26 is delivered to a treatment site in a blood vessel together with the skeletal structure 14 in a state where it is in a contracted state and incorporated into the delivery catheter 10 as shown in Fig. 1, and then the skeletal structure 14 is exposed from the skeletal structure 24 by relatively moving the skeletal structure 14 toward the axial proximal side as shown by the imaginary line in Fig. 3. By this operation, the skeletal structure 14, which has been released from the restraining force of the skeletal structure 24, undergoes a radially expanding deformation due to its self-expansion action, and this radially expanding deformation force of the skeletal structure 14 is directly applied to the inserted stent 26, causing the stent 26 to rapidly expand and deform.

[0050] The expanded stent 26 can be pressed against the inner peripheral surface of the blood vessel and positioned and held in a substantially tight contact state based on its own shape memory properties, etc. Thereafter, the outer tubular member 24 is operated to move the outer tubular member 24 relative to the distal end side of the catheter main body 12 in the axial direction, thereby storing the skeletal structure 14 in the outer tubular member 24 in a contracted state while leaving the stent 26 outside, and then the outer tubular member 24 and the catheter main body 12 are pulled out together from the blood vessel, whereby the stent 26 can be placed in the expanded state at the treatment site in the blood vessel.

[0051] In this embodiment, the skeletal structure 14 has a tapered portion 20 on the base end side, and the outer tubular member 24 is inserted from the tapered portion 20 side, so that the diametrically reduced deformation of the skeletal structure 14 including the holding portion 16 progresses gradually. Therefore, the skeletal structure 14 can be housed again in the outer tubular member 24 more smoothly, and the detachment from the stent 26 is efficiently realized. When the outer tubular member 24 reaches the holding portion 16 with the stent 26 inserted therein, a radial gap is formed between the stent 26 and the holding portion 16, and the outer tubular member 24 can be smoothly inserted therein.

[0052] It is also possible to take measures to improve the shape stability in the expanded state, resistance to radial contraction force, circumferential compressive rigidity, etc. of the stent 26 expanded in the blood vessel. Specifically, when a stent 26 made of a synthetic resin material such as a biodegradable resin is used, it is possible to reduce the amount of radial contraction and recoil rate of the stent 26 after expansion by heating the expanded stent 26, preferably to a temperature equal to or higher than the glass transition point.

[0053] Such heating of the stent 26 can be performed, for example, by inserting a separate heating device into the blood vessel after delivering the stent 26 and removing the catheter body 12, but it is preferable to provide a heating means in the delivery catheter 10.

[0054] 1, a heating means can be configured by providing a heat generating member 30 made of an electric heating material or the like that generates heat when current is applied through a power supply line 28 on the distal end side of the catheter main body 12, and controlling the current to the heat generating member 30 with an external power supply controller 32. As the heat generating member 30, for example, a radiation-type heat generating element that heats the skeletal structure 14 by irradiating it with far infrared rays or the like can be disposed opposite the skeletal structure 14, but it is preferable to dispose a self-heating element that generates heat by itself so that it is kept in contact with or fixed to the skeletal structure 14.

[0055] In such a heating means, the stent 26 is delivered to a treatment site in a blood vessel by the catheter main body 12, and the stent 26 is exposed from the outer tubular member 24 together with the skeletal structure 14 in an expanded state, and then the power supply controller 32 is operated to pass electricity through the heat generating member 30 to generate heat, so that the generated heat can be applied to the stent 26 through the skeletal structure 14. In particular, by making the skeletal structure 14 out of a metal or the like having high thermal conductivity, it becomes possible to diffuse the heat generated by the heat generating member 30 over a wide area of ​​the stent 26, and to apply substantially uniform heating to substantially the entire stent 26.

[0056] Furthermore, when the skeletal structure 14 and the stent 26 are both formed as mesh-like skeletal structures having a plurality of aligned windows, it is preferable that the mesh windows of the skeletal structure 14 are made smaller than those of the stent 26, so that the skeletal structure 14 has a finer skeletal structure. This allows the stent 26 to be held more stably by the skeletal structure 14. Furthermore, when the stent 26 is heated by heat transfer through the skeletal structure 14 as described above, the contact area of ​​the skeletal structure 14 with the stent 26 can be stably secured, and the entire stent 26 can be heated more uniformly.

[0057] Although the embodiments of the present invention have been described in detail above, the present invention should not be construed as being limited to the above specific description.

[0058] For example, the specific skeletal structure of the skeletal structure 14 is not limited. For example, in the above embodiment, a mesh-like skeletal structure is used in which approximately diamond-shaped windows are connected, but the skeletal structure may be a mesh-like structure in which windows of other shapes, such as hexagons, are connected, or a mesh-like structure in which windows of different shapes or sizes are connected. In addition, the linear structural parts constituting the skeleton of the skeletal structure 14 can also be partially made different in thickness to adjust the strength characteristics of expansion and contraction.

[0059] It is also possible to overlap multiple types of mesh-like skeletal structures with different window sizes, shapes, etc. in an internally and externally inserted state to form a skeletal structure 14 that is partially fixed as necessary, which makes it possible to adjust the size of the mesh, etc.

[0060] Furthermore, it is also possible to adopt a tapered stent or the like whose diameter dimension varies in the length direction as the stent 26. In that case, the straight portion (retaining portion 16) of the skeletal structure 14 may also have a diameter dimension in the expanded state that varies in the axial direction so as to correspond to the stent 26.

[0061] 5, the skeletal structure 14 may be provided with a tip portion 34 having a reduced diameter toward the opening 18 at the tip side located closer to the opening 18 than the holding portion 16 where the stent 26 is extrapolated and held. By directing the opening 18 side end of the skeletal structure 14 inward in this manner, it is possible to reduce the risk of damage to the inner surface of the blood vessel by the end portion.

[0062] Furthermore, the delivery catheter according to the present invention may be provided with a sheath that is fitted onto the catheter body 12 in an externally inserted state, or the catheter body 12 may have a structure having multiple lumens, such as a double lumen.

[0063] Furthermore, in the present invention, the outer tubular member 24 that is fitted onto the skeletal structure 14 need only be capable of being fitted onto at least the stent 26 that is fitted onto and held on the skeletal structure 14 and held in a contracted state, and does not need to cover the entire skeletal structure 14.

[0064] In addition, the heat generating member 30 that generates heat when electricity is applied thereto may be configured by the skeletal structure, and the skeletal structure 14 itself may be made to generate heat when electricity is applied to the skeletal structure 14.

[0065] In addition, although not listed one by one, the present invention can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it goes without saying that all such embodiments are included within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0066] 10 Delivery Catheter 12 Catheter body 14 Skeletal Structure 16 Holding part 18 Openings 20 Tapered section 22 Fitting part 24 External cylinder member 26 Stent 28 Power line 30 Heat generating components 32 Power Supply Controller 34 Tip

Claims

1. A delivery catheter used for delivering and placing an expandable indwelling object into a lumen of a living body, the expandable indwelling object being expanded and placed in the lumen of the living body, The device has a shaft portion that can be inserted into a lumen of a living body, A retaining portion having a self-expanding skeletal structure capable of expanding and contracting is provided on the distal end side of the shaft portion, an outer tube member that is disposed to be movable relative to the holding portion in the longitudinal direction, covers the holding portion to hold the holding portion in a contracted state, and exposes the holding portion to allow the holding portion to be deformed to an expanded state; A delivery catheter in which the expandable indwelling object can be held in a contracted state by inserting the expandable indwelling object over the holding portion and covering it with the outer tube member, and in which an expansion force can be applied from the holding portion to the expandable indwelling object by exposing the holding portion from the outer tube member.

2. The delivery catheter according to claim 1 , wherein the holding portion has an open end that opens toward a distal end side.

3. the holding portion has a straight portion that is substantially cylindrical in an expanded state, and a tip portion that is located on a tip side of the straight portion and has a diameter reduced toward an opening on the distal end side, 3. The delivery catheter according to claim 2, wherein the expandable indwelling object is fitted onto and held by the straight portion.

4. 3. The delivery catheter according to claim 1, wherein the expandable indwelling device is fitted onto the holding portion and covered with the outer tubular member, thereby being held in a contracted state when assembled.

5. 5. The delivery catheter according to claim 4, wherein the expandable indwelling device is made of a biodegradable material.

6. The expandable indwelling device has a skeletal structure, 5. The delivery catheter according to claim 4, wherein the retaining portion has a finer skeletal structure than that of the expandable indwelling device.

7. 3. The delivery catheter according to claim 1, further comprising a heating means for heating the holding portion.

8. 8. The delivery catheter of claim 7, wherein the holding portion is made of metal, and the heat generated by the heating means is diffused over a wide area of ​​the holding portion by utilizing the thermal conductivity of the holding portion.

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