Delivery catheter

Abstract

To provide a delivery catheter capable of suppressing an increase in release resistance even when a stent is released with a mount hand side part in an inner shaft present in a bent part of an endoscope and the bent part bent largely.SOLUTION: An inner shaft 10 of a delivery catheter 3 delivering a stent 2 to an affected part includes an inner tube 11 and an inner tube 12. A distal end part of the inner tube 12 extends from the inner tube 11 and composes a stent mount part 12a. The inner shaft 10 is movably inserted in an outer tube 4 in an axial direction. An adhesive filling region 15 including an adhesive layer 16 adhering the inner tube 11 in the inner shaft 10 and the inner tube 12 is provided on the hand side away from the stent mount part 12a. A mount hand side part 14 more flexible than the adhesive filling region 15 is placed between the stent mount part 12a and the adhesive filling region 15.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a delivery catheter for delivering a stent to a stenosis in a body lumen, and more particularly to a delivery catheter suitable for being inserted through a channel of an endoscope and used.

Background Art

[0002] For example, when a body lumen such as the large intestine is stenosed due to a lesion such as colorectal cancer, a surgical method is known in which a cylindrical stent is placed in the stenosis to maintain a patent state. The stent is delivered to the stenosis by a delivery catheter and released.

[0003] Generally, as disclosed in Patent Document 1, for example, a delivery catheter includes an inner shaft and an outer tube. The inner shaft includes an inner tube through which a guide wire passes and an inner tube that covers the inner tube. The distal end portion of the inner tube extends out from the inner tube to form a stent mounting portion. The stent before release is held in a constricted state between the outer periphery of the stent mounting portion and the outer tube. An endoscope visual recognition marker of a conspicuous color is provided on the outer periphery of the distal end portion of the inner tube located near the proximal side of the stent mounting portion. The endoscope visual recognition marker can be visually recognized from the outside through the transparent outer tube.

[0004] A centering tube for centering is interposed between the distal end portion of the inner tube and the inner tube. The distal end portion of the inner tube, the centering tube, and the inner tube are adhered with an adhesive. Therefore, a portion of the inner shaft over a length of several centimeters (for example, about 3 cm to 4 cm) immediately proximal to the stent mounting portion is a relatively hard adhesive filling region.

[0005] The delivery catheter is usually used in combination with an endoscope. After the endoscope is inserted along the body lumen to near the stenosis, the delivery catheter is inserted through the channel of the endoscope. Eventually, the endoscopic visual marker enters the field of view of the endoscope and is displayed on the endoscopic monitor. This allows confirmation that the entire stent mount portion has protruded from the distal end of the endoscope. Thereafter, the outer tube is pulled toward the operator side with respect to the inner shaft, and the stent release operation is performed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the clinical field, the stent may be released when the stent mount portion does not protrude sufficiently from the endoscope. In such a case, the proximal side portion of the mount on the proximal side of the stent mount portion in the inner shaft is in a state of being disposed inside the curved portion near the distal end of the endoscope, and the stent release is performed. At this time, assuming that the curved portion is greatly bent, the relatively hard adhesive filling region included in the proximal side portion of the mount does not bend to the same curvature as the curved portion. Therefore, at one or several locations within the curved portion, the tube wall of the outer tube strongly contacts the inner peripheral surface of the curved portion or the proximal side portion of the mount, or is strongly sandwiched between the inner peripheral surface of the curved portion and the proximal side portion of the mount (see Fig. 6(b)). For this reason, the release resistance increases. If the release resistance is too large, there is a risk that the outer tube will break. In view of such circumstances, an object of the present invention is to provide a delivery catheter capable of suppressing an increase in release resistance even when the stent is released in a state where the proximal side portion of the mount in the inner shaft is within the curved portion of the endoscope and the curved portion is greatly bent.

Means for Solving the Problem

[0008] To solve the above problems, the present invention provides a delivery catheter for delivering a stent to a lesion, including an inner tube and an inner shaft covered by the inner tube, wherein a distal end portion of the inner shaft extends beyond the inner tube to form a stent mount portion, an outer tube through which the inner shaft is axially movably inserted, and is provided with an adhesive filling region including an adhesive layer that adheres the inner tube and the inner shaft in the inner shaft is provided away from the hand side of the stent mount portion, and a mount hand side portion more flexible than the adhesive filling region is interposed between the stent mount portion and the adhesive filling region. Preferably, the length of the mount hand side portion is equal to or greater than the length of the curved portion of the endoscope.

[0009] According to the delivery catheter, when the entire stent mount portion protrudes from the distal end of the endoscope, the mount hand side portion is disposed inside the curved portion of the endoscope, and the adhesive filling region is disposed inside the insertion portion on the hand side of the curved portion of the endoscope. At this time, if the curved portion is bent, the flexible mount hand side portion can be bent to the same extent as the curved portion accordingly. Therefore, the pressing force or pinching force received by the tube wall of the outer tube from the inner peripheral surface of the curved portion and the mount hand side portion is reduced. As a result, an increase in release resistance can be suppressed during the stent release operation. As a result, breakage of the outer tube or the like can be prevented.

[0010] Preferably, the delivery catheter according to the present invention further includes an endoscope visual recognition marker disposed near the proximal side of the stent mounting portion in the inner shaft. When the endoscope visual recognition marker is located around the distal end of the endoscope or slightly protrudes from the distal end of the endoscope, the endoscope visual recognition marker enters the visual field of the endoscope. Thereby, it can be confirmed that the entire stent mounting portion protrudes from the distal end of the endoscope. In a preferred embodiment of the present invention, the distal end of the inner tube is disposed at a distance equal to the length of the proximal side portion of the mount from the proximal side of the endoscope visual recognition marker. Thereby, the outer diameter of the proximal side portion of the mount can be made smaller than the outer diameter of the inner tube. Therefore, the pressing force or clamping force received by the tube wall of the outer tube from the inner peripheral surface of the curved portion and the proximal side portion of the mount can be reliably reduced. Thereby, an increase in release resistance can be sufficiently suppressed, and breakage of the outer tube can be reliably prevented.

[0011] A further preferred embodiment of the present invention is that the inner shaft further includes an intermediate tube that extends from a position near the proximal side of the stent mounting portion across the proximal side portion of the mount to the adhesive filling region, and the inner tube is passed through the intermediate tube. The endoscope visual recognition marker is provided on the outer periphery of the distal end portion of the intermediate tube. The proximal end portion of the intermediate tube is interposed between the inner periphery of the distal end portion of the inner tube and the outer periphery of the inner tube and is adhered to the inner tube and the inner tube through the adhesive layer. The intermediate tube has a smaller diameter than the inner tube and functions as a centering tube that centers the inner tube and the inner pipe, and also functions to support the endoscopic viewing marker and connect it to the inner tube. The outer peripheral portion of the proximal side portion of the mount is constituted by the intermediate tube. Therefore, when the proximal side portion of the mount is disposed inside the curved portion of the endoscope, the outer tube is sandwiched between the inner peripheral surface of the curved portion and the intermediate tube. Since the intermediate tube has a smaller diameter than the inner tube, the pressing force or clamping force received by the tube wall of the outer tube is reduced. As a result, an increase in release resistance can be sufficiently suppressed. Consequently, breakage of the outer tube can be reliably prevented.

[0012] Preferably, an annular release receiving member is provided on the outer periphery of the distal end portion of the intermediate tube, and the endoscopic viewing marker is provided on the outer periphery of the release receiving member. The distal end face of the release receiving member constitutes a release receiving surface against which the proximal end of the stent can abut. When pulling the outer tube proximally with respect to the inner shaft for stent release, the proximal end of the stent abuts against the release receiving surface of the release receiving member, thereby preventing the stent from being pulled proximally together with the outer tube. As a result, the stent can be reliably released.

[0013] Preferably, a tapered guiding portion that tapers toward the proximal side from the release receiving member is provided on the outer periphery of the intermediate tube. Thereby, when assembling the delivery catheter, the distal end of the outer tube can be smoothly guided onto the outer periphery of the release receiving member along the guiding portion. That is, it is possible to prevent the distal end of the outer tube from hitting and getting caught on the proximal end of the release receiving member.

[0014] Preferably, the guiding portion is constituted by an adhesive that is integral with an adhesive layer interposed between the intermediate tube and the release receiving member. Accordingly, when filling an adhesive between the intermediate tube and the release receiving member during the production of the inner shaft, a guide portion can be formed with the same adhesive, and the formation of the adhesive layer and the guide portion can be made efficient.

[0015] Preferably, the release receiving member is constituted by a resin tube having the same material and the same diameter as the inner tube. Accordingly, the end material of the resin tube used as the inner tube can be used as the release receiving member.

[0016] Here, when the intermediate tube is exposed on the outer periphery of the mount proximal side portion of the inner shaft, the clearance between the inner diameter of the outer tube surrounding the mount proximal side portion and the outer diameter of the mount proximal side portion becomes large. Then, when bent, the cross-sectional shape of the outer tube may be deformed from circular to flat, and the outer tube is likely to kink. Therefore, in the further preferred embodiment, one or a plurality of annular kink prevention members may be provided at intervals in the axial direction on the outer periphery of the intermediate tube in the mount proximal side portion. Accordingly, in addition to being able to prevent an increase in release resistance by maintaining the bendability of the mount proximal side portion, the kink of the outer tube can be prevented by holding the cross-sectional shape of the outer tube in a circular shape by the kink prevention member.

[0017] In the one preferred embodiment, a tubular kink prevention member that is more flexible than the inner tube and has an outer diameter equal to or less than the outer diameter of the inner tube may be provided in the mount proximal side portion. Accordingly, it is possible to prevent an increase in release resistance by maintaining the bendability of the mount proximal side portion, and to prevent the kink of the outer tube. The tubular kink prevention member may be a spiral tube. The tubular kink prevention member may have a smaller wall thickness than the inner tube. The tubular kink prevention member may have a lower hardness than the inner tube.

Advantages of the Invention

[0018] According to the delivery catheter of the present invention, even when a stent is released in a state where the proximal side portion of the inner shaft at the hand side of the mount is within the curved portion of the endoscope and the curved portion is bent greatly, an increase in release resistance can be suppressed.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. <First Embodiment (FIGS. 1 to 6)> As shown in FIG. 1(a), a delivery system 1 includes a stent 2 and a delivery catheter 3. As shown in FIGS. 1(b) and 1(c), the stent 2 has an expandable tubular network structure. By delivering the stent 2 to a stenosis (lesion) (not shown) by the delivery catheter 3 and releasing and implanting it, the stenosis is kept in an open state. Note that the delivery system 1 of the present embodiment is a colon delivery system applied to the procedure for opening a stenosis in the colon blocked by colon cancer or the like, but the present invention is not limited to this.

[0021] As shown in FIG. 1(a), the delivery catheter 3 includes an outer tube 4 and an inner shaft 10. At least the distal portion (the left side in FIG. 1(a)) of the outer tube 4 is transparent. As shown in FIG. 1(b), the inner shaft 10 is inserted into the outer tube 4 so as to be movable in the axial direction (left and right in FIG. 1(b)). As shown in FIG. 1(c), the inner shaft 10 includes an inner tube 11, an inner pipe 12, and an intermediate tube 13. The inner tube 12 is covered by the inner tube 11.

[0022] As shown in FIG. 2, an intermediate tube 13 is provided between the distal end portion 11a of the inner tube 11 and the inner pipe 12. The intermediate tube 13 has a smaller diameter than the inner tube 11 and a larger diameter than the inner pipe 12. As shown in FIG. 4, the wall thickness t of the intermediate tube 13 13 is smaller than the difference between the inner radius of the inner tube 11 and the outer radius of the inner pipe 12. As shown in FIG. 2, the length of the intermediate tube 13 is preferably several tens of mm to several hundreds of mm, for example, about one hundred and several tens of mm. The intermediate tube 13 extends distally (the left side in FIG. 2) from the inner tube 11.

[0023] As shown in FIG. 2, the inner pipe 12 is passed through the inner tube 11, extends distally (the left side in FIG. 2) from the inner tube 11, and is passed through the intermediate tube 13. As shown in FIGS. 1(b) and 1(c), the distal end portion of the inner pipe 12 extends further distally (the left side in FIG. 1(c)) than the intermediate tube 13. The portion of the inner pipe 12 that extends beyond the intermediate tube 13 constitutes a stent mount portion 12a. As shown in FIG. 1(b), the stent 2 before release is held in a constricted state between the outer periphery of the stent mount portion 12a and the outer tube 4. A guide wire 5 for guiding the delivery catheter 3 is passed through the inside of the inner pipe 12.

[0024] As shown in FIG. 2, a mount proximity piece 20 is provided at a position 10p on the inner shaft 10 that is close to the proximal end portion 13a of the intermediate tube 13, that is, the end near the stent mount portion 12a. The mount proximity piece 20 includes a release receiving member 21 and an endoscope visual recognition marker 22.

[0025] As shown in FIG. 2, the release receiving member 21 is formed in a short tubular or annular shape. The axial length L of the release receiving member 21 21 is preferably about several millimeters, more preferably L 21 = about 3 mm. The material of the release receiving member 21 is the same resin material as the inner tube 11. The outer diameter of the release receiving portion 21 is equal to the outer diameter of the inner tube 11, and the inner diameter of the release receiving portion 21 is equal to the inner diameter of the inner tube 11. Preferably, the release receiving member 21 is constituted by a resin tube of the same material and the same diameter as the inner tube 11. Thus, the end material of the resin tube used as the inner tube 11 can be used as the release receiving member 21.

[0026] The release receiving member 21 is fitted on the outer periphery of the proximal end portion 13a of the intermediate tube 13. The distal end face of the release receiving member 21 constitutes a release receiving surface 21a against which the proximal end of the stent 2 can abut. As shown in FIG. 3, an adhesive layer 25 is interposed between the release receiving member 21 and the intermediate tube 13.

[0027] As shown in FIG. 2, an endoscope visual recognition marker 22 is provided on the outer periphery of the release receiving member 21. Therefore, an endoscope visual recognition marker 22 is provided on the outer periphery of the proximal end portion of the intermediate tube 13. The endoscope visual recognition marker 22 is constituted by a colored adhesive tape of a conspicuous color such as white, and is annularly attached to the outer periphery of the release receiving member 21. As shown in FIG. 3, the adhesive layer 22b on the inner peripheral surface of the endoscope visual recognition marker 22 is adhered to the outer peripheral surface of the release receiving member 21. As shown in FIG. 2, preferably, the axial length L of the endoscope visual recognition marker 22 22 is the axial length L of the release receiving member 21 21is approximately equal to, on the order of several millimeters (e.g., L 22 = about 3 mm). As shown in Fig. 1(b), the endoscopic visual recognition marker 22 is visible from the outside of the delivery catheter 3 through the transparent outer tube 4.

[0028] As shown in Fig. 3, an X-ray marker 23 is sandwiched between the distal end portion 13a of the intermediate tube 13 and the inner tube 12. The X-ray marker 23 is composed of a thin-walled annular X-ray-impermeable metal having a diameter smaller than the inner diameter of the release receiving member 21. Adhesive layers 27 and 28 are interposed between the outer periphery of the X-ray marker 23 and the intermediate tube 13, and between the inner periphery of the X-ray marker 23 and the inner tube 12, respectively.

[0029] As shown in Fig. 2, a guide portion 24 is provided on the outer periphery of the intermediate tube 13. The guide portion 24 is formed in a tapered shape that decreases in diameter axially from the proximal end face 21b of the release receiving member 21 toward the proximal side in the axial direction (the right side in Fig. 2). The axial length of the guide portion 24 is less than 1 mm to on the order of several millimeters. The guide portion 24 is composed of an adhesive 26 that is the same as the adhesive layer 25 interposed between the intermediate tube 13 and the release receiving member 21.

[0030] When manufacturing the inner shaft 10, when filling the adhesive 26 between the intermediate tube 13 and the release receiving member 21, the guide portion 24 can be formed with the same adhesive 26. Therefore, the formation of the adhesive layer 25 and the guide portion 24 can be made more efficient.

[0031] When assembling the delivery system 1, the distal end of the outer tube 4 can be smoothly guided onto the outer periphery of the release receiving member 21 along the guide portion 24. In short, it is possible to prevent the distal end of the outer tube 4 from hitting and getting caught on the proximal end face 21b of the release receiving member 21.

[0032] As shown in FIG. 2, in the inner shaft 10, the portion from the endoscope visual recognition marker 22 to the distal end 11e of the inner tube 11 constitutes the proximal side portion 14 at the handpiece. In the proximal side portion 14 at the handpiece, the intermediate tube 13 is exposed on the outer periphery of the inner shaft 10. The length L 14 of the proximal side portion 14 at the handpiece is sufficiently larger than the axial length of the release receiving member 21 and the length L 6a of the bending portion 6a of the endoscope 6 described later. (L 14 ≧L 6a ), for example, L 14 is about ten-odd cm, preferably L 14 is about 12 cm. By setting L 14 ≧L 6a , the proximal side portion 14 at the handpiece can be arranged over the entire length within the bending portion 6a, and the distal end 15e of the adhesive filling region 15 described later can be arranged within the insertion portion 6b on the proximal side of the bending portion 6a (FIG. 5). Note that the axial length of the tapered guide portion 24 is sufficiently smaller than the length L 14 of the entire proximal side portion 14 at the handpiece.

[0033] As shown in FIG. 2, the distal end 11e of the inner tube 11 is separated from the endoscope visual recognition marker 22 by the length of the proximal side portion 14 at the handpiece on the proximal side. The proximal end portion 13b of the intermediate tube 13 is inserted into the distal end portion 11a of the inner tube 11 and is interposed between the inner periphery of the inner tube 11 and the outer periphery of the inner tube 12.

[0034] As shown in FIG. 2, an adhesive filling region 15 is formed on the proximal side (the right side in FIG. 2) of the proximal side portion 14 at the handpiece in the inner shaft 10. The adhesive filling region 15 is arranged farther on the proximal side than the endoscope visual recognition marker 22 and thus the stent mount portion 12a. In other words, the proximal side portion 14 at the handpiece is interposed between the stent mount portion 12a and the adhesive filling region 15. The intermediate tube 13 straddles the adhesive filling region 15 through the proximal side portion 14 at the handpiece from the proximal side proximity position 10p at the handpiece.

[0035] As shown in FIG. 4, in the adhesive filling region 15, the inner tube 11, the intermediate tube 13, and the inner pipe 12 are adhered by an adhesive layer 16. Therefore, the adhesive filling region 15 is harder than the mount proximal portion 14 and also harder than the shaft portion 17 (FIG. 2) on the proximal side of the inner shaft 10 with respect to the adhesive filling region 15. In other words, the mount proximal portion 14 has a lower bending rigidity and is softer (more flexible) than the adhesive filling region 15.

[0036] As shown in FIG. 2, the distal end 15e of the adhesive filling region 15 is disposed at the same axial position as the distal end 11e of the inner tube 11. The proximal end 15d of the adhesive filling region 15 is disposed on the proximal side (right side in FIG. 2) of the intermediate tube 13. The proximal end 13d of the intermediate tube 13 is disposed at the axial middle portion of the adhesive filling region 15. The length L of the adhesive filling region 15 15 is preferably about several cm, more preferably L 15 = about 3 cm to 4 cm.

[0037] As shown in FIG. 4, the adhesive layer 16 includes an adhesive layer portion 16a filled between the inner tube 11 and the intermediate tube 13, an adhesive layer portion 16b filled between the intermediate tube 13 and the inner pipe 12, and an adhesive layer portion 16c filled between the inner tube 11 and the inner pipe 12 on the proximal side (right side in FIG. 4) of the proximal end 13d of the intermediate tube 13. These adhesive layer portions 16a to 16c are constituted by the same adhesive 16d. At the proximal end 13d of the intermediate tube 13, the two adhesive layer portions 16a, 16b and the adhesive layer portion 16c are integrally continuous.

[0038] As shown in FIG. 4, an injection hole 11d for injecting the adhesive 16d is formed in the vicinity of the proximal end 13d of the intermediate tube 13 in the inner tube 11. The injection hole 11d penetrates from the outer peripheral surface to the inner peripheral surface of the inner tube 11.

[0039] As shown in FIG. 1(a), usually, this type of delivery system 1 is used in combination with an endoscope 6 shown by the two-dot chain line in the figure. The endoscope 6 is inserted into, for example, the large intestine (internal lumen) of a patient (not shown) from the anus, and is directed at the stenosed lesion. Next, the guide wire 5 shown in FIG. 1(b) is inserted into the forceps channel 6c of the endoscope 6. Further, the distal end portion of the guide wire 5 is passed through the lesion. Subsequently, the delivery system 1 is inserted into the forceps channel 6c of the endoscope 6 along the guide wire 5. Eventually, the endoscope visual recognition marker 22 enters the visual field of the endoscope 6 and is projected onto an endoscope monitor (not shown). Thereby, it can be confirmed that the stent mount portion 12a has protruded from the endoscope 6 and reached the lesion.

[0040] Then, as shown in FIG. 1(c), by pulling the outer tube 4 toward the operator side with respect to the inner shaft 10, the stent 2 is released. At this time, when the proximal end of the stent 2 abuts against the release receiving surface 21a of the release receiving member 21, the stent 2 is prevented from being drawn toward the operator side together with the outer tube 4. Thereby, the stent 2 can be reliably released.

[0041] As shown in FIG. 5, depending on the situation, there may be a case where the stent 2 should be released in a state where the stent mount portion 12a has not sufficiently protruded from the endoscope 6 and, moreover, in a state where the bendable bending portion 6a of the endoscope 6 is greatly bent. In this case, the endoscope visual recognition marker 22 is located around the distal end 6e of the endoscope 6 or protrudes slightly from the distal end 6e of the endoscope 6, and the mount proximal side portion 14 is disposed inside the bending portion 6a of the endoscope 6. The adhesive filling region 15 is disposed inside the insertion portion 6b on the operator side of the bending portion 6a of the endoscope 6. Since the insertion portion 6b has a smaller curvature than the bending portion 6a, excessive sliding friction does not act between the adhesive filling region 15 and the outer tube 4 during stent release.

[0042] As shown in FIG. 6( a), the flexible mount proximal portion 14 located within the curved portion 6a can bend to the same extent as the curved portion 6a, following the curve of the curved portion 6a. This reduces the pressing or pinching force that the tube wall of the outer tube 4 receives from the inner circumferential surface of the curved portion 6a and the mount proximal portion 14. (If the mount proximal portion 14' were rigid and difficult to bend because it included the adhesive-filled region 15', as shown in FIG. 6( b), the tube wall of the outer tube 4 would be pressed strongly against the inner circumferential surface of the curved portion 6a or the mount proximal portion 14' or pinched firmly between the inner circumferential surface of the curved portion 6a and the mount proximal portion 14' at one or several locations.) Furthermore, because the mount proximal portion 14 has a smaller diameter than the adhesive-filled region 15 and the inner tube 11, the pressing or pinching force that the tube wall of the outer tube 4 receives can be further reduced.

[0043] This reduces the sliding friction between the outer tube 4 and the inner circumferential surface of the bending section 6a, and between the outer tube 4 and the proximal mount portion 14, when the outer tube 4 is pulled toward the proximal side relative to the inner shaft 10 to release the stent 2, thereby keeping the release resistance low. As a result, breakage of the outer tube 4 can be prevented.

[0044] After the stent 2 is released, the delivery catheter 3 and the guide wire 5 are withdrawn. The stent 2 can maintain the patency of the lesion by being placed in the lesion in an expanded state.

[0045] Next, another embodiment of the present invention will be described. In the following embodiment, the same components as those already described will be denoted by the same reference numerals in the drawings and the description thereof will be omitted. <Second embodiment (FIGS. 7 and 8)> As shown in FIG. 7, in the delivery catheter 3B according to the second embodiment of the present invention, one or a plurality of kink prevention members 30 are provided on the outer periphery of the intermediate tube 13 in the mount proximal portion 14. Preferably, the plurality of kink prevention members 30 are arranged at intervals in the axial direction of the mount proximal portion 14. More preferably, the plurality of kink prevention members 30 are provided at equal intervals. Each kink prevention member 30 is preferably formed in an annular shape of the same material and the same cross-sectional dimensions (outer diameter, inner diameter) as the release receiving member 21. And the axial length of each kink prevention member 30 is about the same (several mm) as the axial length of the release receiving member 21.

[0046] An adhesive 31 is provided between the inner peripheral surface of the kink prevention member 30 and the outer peripheral surface of the intermediate tube 13. The kink prevention member 30 is fixed to the intermediate tube 13 by the adhesive 31.

[0047] Between adjacent kink prevention members 30 in the mount proximal portion 14 and both end portions of the mount proximal portion 14 are resistance suppression portions 14a. In the resistance suppression portion 14a, the intermediate tube 13 is exposed on the outer periphery of the inner shaft 10. The outer diameter of the resistance suppression portion 14a is smaller than the outer diameter of the kink prevention member 30. Therefore, the relatively large-diameter kink prevention members 30 and the relatively small-diameter resistance suppression portions 14a are alternately arranged in the axial direction of the mount proximal portion 14.

[0048] Since the resistance suppression portion 14a does not include the kink prevention member 30, it has a lower bending rigidity and is more flexible and easier to bend than the adhesive filling region 15. As a result, the mount proximal portion 14 is more flexible and easier to bend as a whole than the adhesive filling region 15. Therefore, as shown in FIG. 8, even if the bending portion 6a of the endoscope 6 is greatly bent during the release operation, the mount proximal portion 14 can be sufficiently bent following the bending portion 6a. Thereby, an increase in the release resistance applied to the outer tube 4 can be prevented.

[0049] As shown in Fig. 7, a relatively large clearance CL is formed between the inner peripheral surface of the outer tube 4 and the outer peripheral surface of the resistance suppression portion 14a. 14a Thus, the contact area between the outer tube 4 and the mount proximal portion 14 can be reduced, and the frictional resistance during the release operation can be reduced. As a result, the release resistance applied to the outer tube 4 during the release operation can be reliably suppressed, and breakage of the outer tube 4 can be reliably prevented.

[0050] On the other hand, the clearance CL between the inner peripheral surface of the outer tube 4 and the outer peripheral surface of the kink prevention member 30 30 is sufficiently smaller than the clearance CL 14a (CL 30 < CL 14a ). Thereby, the cross-sectional shape of the outer tube 4 surrounding the mount proximal portion 14 can be maintained circular. In particular, as shown in Fig. 8, even if the mount proximal portion 14 within the curved portion 6a is greatly curved, the kink prevention member 30 can maintain the cross-sectional shape of the outer tube 4 circular. That is, it is possible to prevent the cross-section of the outer tube 4 from being deformed so as to be flattened. As a result, according to the delivery catheter 3B, it is possible to prevent the outer tube 4 from kinking while preventing an increase in the release resistance.

[0051] <Third Embodiment (Fig. 9)> As shown in Fig. 9(a), in the delivery catheter 3C according to the third embodiment of the present invention, a tubular kink prevention member 32 is provided on the outer periphery of the intermediate tube 13 in the mount proximal portion 14. The kink prevention member 32 is preferably constituted by a resin tube of the same material and the same cross-sectional dimensions (outer diameter, inner diameter) as the release receiving member 21. The kink prevention member 32 extends over the entire length of the mount proximal portion 14. The proximal end 32d of the kink prevention member 32 abuts against the distal end 11e of the inner tube 11. The distal end 32e of the kink prevention member 32 abuts against the proximal end 21b of the release receiving member 21.

[0052] The kink prevention member 32 is not fixed to the intermediate tube 13. An adhesive is not provided between the inner peripheral surface of the kink prevention member 32 and the outer peripheral surface of the intermediate tube 13, and a clearance (clearance) corresponding to the difference in their diameters is formed. Therefore, the kink prevention member 32 is slidable with respect to the intermediate tube 13.

[0053] As shown in Fig. 9(b), a spiral slit 33 is formed in the kink prevention member 32. The spiral slit 33 is in the form of a cut penetrating from the outer peripheral surface to the inner peripheral surface of the kink prevention member 32 and extends in a helical shape over the entire area of the kink prevention member 32. The width w of the spiral slit 33 33 is preferably w 33 = 0 to about several millimeters in a state where no external force such as tension is applied to the kink prevention member 32. As a result, the kink prevention member 32 is in a spiral tubular shape. Therefore, the kink prevention member 32 is more flexible and easier to bend than the inner tube 11. Consequently, the mount hand side portion 14 including the kink prevention member 32 is more flexible and easier to bend than the adhesive filling region 15 including the inner tube 11 and the adhesive layer 16.

[0054] Therefore, even if the bending portion 6a (see Fig. 5) is greatly bent during the release operation, the mount hand side portion 14 can be sufficiently bent following the bending portion 6a. This can prevent an increase in the release resistance applied to the outer tube 4.

[0055] Moreover, the outer tube 4 within the bending portion 6a is held in a circular cross-sectional shape by the kink prevention member 32. Since the kink prevention member 32 is provided over the entire area of the mount hand side portion 14, the cross-sectional shape of the outer tube 4 can be held in a circular shape over the entire area of the mount hand side portion 14 and thus over the entire area of the bending portion 6a. As a result, it is possible to reliably prevent kinking of the outer tube 4 while preventing an increase in the release resistance.

[0056] <Fourth Embodiment (Fig. 10)> As shown in Fig. 10, in the delivery catheter 3D according to the fourth embodiment of the present invention, a protection tube 34 (kink prevention member) is provided at the proximal side portion 14 of the mount. Preferably, the protection tube 34 is continuously connected integrally with the inner tube 11. The inner tube 11 and the protection tube 34 are formed of a common resin tube. In other words, the distal end of the resin tube constituting the inner tube 11 extends to the proximal end 21b of the release receiving member 21, and the portion disposed at the proximal side portion 14 of the mount in the resin tube constitutes the protection tube 34. The material of the protection tube 34 is the same as that of the inner tube 11.

[0057] The protection tube 34 is provided over the entire length of the proximal side portion 14 of the mount. The distal end 34e of the protection tube 34 abuts against the proximal end 21b of the release receiving member 21.

[0058] The inner diameter of the protection tube 34 is equal to the inner diameter of the inner tube 11. The inner peripheral surface of the protection tube 34 and the inner peripheral surface of the inner tube 11 are flush and continuous. On the other hand, the outer diameter of the protection tube 34 is smaller than the outer diameter of the inner tube 11. A step 10d is formed between the outer peripheral surface of the protection tube 34 and the outer peripheral surface of the inner tube 11. Therefore, the thickness of the protection tube 34 is smaller than the thickness of the inner tube 11.

[0059] The outer peripheral surface of the protection tube 34 constitutes the outer peripheral surface of the proximal side portion 14 of the mount. Therefore, the outer diameter of the proximal side portion 14 of the mount is larger than the outer diameter of the intermediate tube 13.

[0060] The protection tube 34 is not fixed to the intermediate tube 13. No adhesive is provided between the inner peripheral surface of the protection tube 34 and the outer peripheral surface of the intermediate tube 13, and a clearance (gap) corresponding to the difference in their diameters is formed.

[0061] Since the protective tube 34 is thinner than the inner tube 11, it has higher flexibility than the inner tube 11. Therefore, the part 14 on the side of the mount hand is more flexible and easier to bend than the adhesive filling area 15. Thus, even if the bending part 6a (see FIG. 5) is greatly bent during the release operation, the part 14 on the side of the mount hand can be bent sufficiently following the bending part 6a. Thereby, an increase in the release resistance applied to the outer tube 4 can be prevented. Also, since the protective tube 34 has a larger diameter than the intermediate tube 13, it is possible to prevent the cross-sectional shape of the outer tube 4 surrounding the protective tube 34 from being deformed so as to be crushed. As a result, it is possible to prevent an increase in the release resistance while preventing kinking of the outer tube 4.

[0062] <Modification Example of the Fourth Embodiment (FIG. 11)> In the modification example of the fourth embodiment shown in FIG. 11, the protective tube 35 (kink prevention member) is constituted by a resin tube separate from the inner tube 11. The protective tube 35 extends over the entire length of the part 14 on the side of the mount hand. The proximal end 35d of the protective tube 35 abuts against the distal end 11e of the inner tube 11. The distal end 35e of the protective tube 35 abuts against the proximal end 21b of the release receiving member 21. Preferably, the protective tube 35 is constituted by the same resin material as the inner tube 11. The point that the protective tube 35 has a smaller outer diameter and is thinner than the inner tube 11 is the same as the protective tube 34 of the fourth embodiment (FIG. 10).

[0063] <Fifth Embodiment (FIG. 12)> As shown in FIG. 12, in the delivery catheter 3E according to the fifth embodiment, the protection tube 36 (kink prevention member) is constituted by a resin tube that is separate from the inner tube 11 and made of a different material. The resin tube constituting the protection tube 36 is preferably a heat shrinkable tube. The protection tube 36 extends over the entire length of the mount proximal side portion 14. The proximal end 36d of the protection tube 36 abuts against the distal end 11e of the inner tube 11. The distal end 36e of the protection tube 36 abuts against the proximal end 21b of the release receiving member 21.

[0064] The cross-sectional dimension of the protection tube 36 (in the case of a heat shrinkable tube, the dimension after shrinkage; the same applies hereinafter) is the same as the cross-sectional dimension of the inner tube 11. The outer peripheral surface of the protection tube 36 and the outer peripheral surface of the inner tube 11 are continuously flush without a step. Note that the outer diameter, inner diameter, and wall thickness of the protection tube 36 and the inner tube 11 may be different from each other. For example, the inner diameter of the protection tube 36 may be smaller than the inner diameter of the inner tube 11, and the outer diameter of the protection tube 36 may be smaller than the outer diameter of the inner tube 11. Also, if the protection tube 36 is a soft tube, the inner diameter of the protection tube 36 may be larger than the outer diameter of the intermediate tube 13, and the outer diameter of the protection tube 36 may be smaller than the outer diameter of the inner tube 11.

[0065] The resin material constituting the protection tube 36 has a lower hardness than the resin material constituting the inner tube 11. Therefore, the protection tube 36 has a lower bending rigidity than the inner tube 11, is flexible, and is easy to bend. For this reason, the mount proximal side portion 14 is more flexible and easier to bend than the adhesive filling region 15.

[0066] Therefore, even if the curved portion 6a (see FIG. 5) is greatly curved during the release operation, the portion 14 on the operator's hand side of the mount can be sufficiently curved following the curved portion 6a. As a result, an increase in the release resistance applied to the outer tube 4 can be prevented. Further, since the protective tube 36 has the same diameter as the inner tube 11, the cross-sectional shape of the outer tube 4 surrounding the protective tube 36 can be surely maintained circular. As a result, while preventing an increase in the release resistance, kinking of the outer tube 4 can be surely prevented.

[0067] <Sixth Embodiment (FIG. 13)> As shown in FIG. 13, in the delivery catheter 3F according to the sixth embodiment, the intermediate tube and the protective tube are constituted by a common tube 37 with respect to each other. In other words, the intermediate tube and the protective tube (kink prevention member) are integrally connected to form the common tube 37. Alternatively, the intermediate tube also serves as the protective tube. Or the protective tube also serves as the intermediate tube. Preferably, the resin material constituting the common tube 37 has a lower hardness than the resin material constituting the inner tube 11. Therefore, the common tube 37 has a lower bending rigidity than the inner tube 11, is flexible, and is easily bent.

[0068] The common tube 37 extends along the axial direction of the delivery catheter 3F from the position of the mount proximity piece 20, through the portion 14 on the operator's hand side of the mount, to the position of the distal end portion 11a of the inner tube 11. The common tube 37 includes tube portions 37a and 37b on both axial end sides and a protective tube portion 37c between these end side tube portions 37a and 37b.

[0069] The distal-side tube portions 37a and 37b are thinner than the protective tube 37c. That is, the outer diameter of the distal-side tube portions 37a and 37b is smaller than the outer diameter of the protective tube portion 37c. A step 37d is formed between the outer peripheral surface of the distal-side tube portion 37a and the outer peripheral surface of the protective tube portion 37c. A step 37e is formed between the outer peripheral surface of the protective tube portion 37c and the outer peripheral surface of the proximal-side tube portion 37b. The inner diameter of the common tube 37 is constant over the entire length and is larger than the outer diameter of the inner tube 12. The inner tube 12 is passed through the common tube 37.

[0070] The distal-side tube portion 37a is arranged so as to be sandwiched between the release receiving member 21 and the X-ray marker 23. Although detailed illustration is omitted, adhesive layers 25 and 27 (see FIG. 3) are interposed between the release receiving member 21 and the distal-side tube portion 37a, and between the distal-side tube portion 37a and the X-ray marker 23, respectively. The step 37d abuts against the proximal-side end face 21b of the release receiving member 21.

[0071] The proximal-side tube portion 37b is inserted into the distal end portion 11a of the inner tube 11 and is interposed between the inner periphery of the inner tube 11 and the outer periphery of the inner tube 12. Although detailed illustration is omitted, adhesive layer portions 16a and 16b (see FIG. 4) are interposed between the inner tube 11 and the proximal-side tube portion 37b, and between the proximal-side tube portion 37b and the inner tube 12, respectively. The step 37d abuts against the distal end 11e of the inner tube 11.

[0072] The protective tube portion 37c extends over the entire area of the mount proximal-side portion 14 and covers the outer periphery of the inner tube 12 in the mount proximal-side portion 14. Preferably, the outer diameter of the protective tube portion 37c is smaller than the outer diameter of the inner tube 11 and larger than the inner diameter of the inner tube 11. Note that the outer diameter of the protective tube portion 37c may be the same as the outer diameter of the inner tube 11.

[0073] According to the delivery catheter 3F, since the protective tube portion 37c has a lower bending rigidity than the inner tube 11, is flexible, and is easily bent, the mount proximal side portion 14 is more flexible and easier to bend than the adhesive filling region 15. Therefore, at the time of the release operation, when the bending portion 6a (see FIG. 5) is greatly bent, the mount proximal side portion 14 can be sufficiently bent following the bending portion 6a. Further, since the outer diameter of the protective tube portion 37c is larger than the inner diameter of the inner tube 11, the cross-sectional shape of the outer tube 4 surrounding the protective tube portion 37c can be surely maintained in a circular shape. As a result, it is possible to surely prevent kinking of the outer tube 4 while preventing an increase in release resistance.

[0074] The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, in the delivery catheter 3 of the first embodiment (FIG. 2), the inner tube 11 may extend distally (toward the endoscope visual recognition marker 22 side) from the adhesive filling region 15. The distal end 11e of the inner tube 11 may be disposed at an intermediate portion of the mount proximal side portion 14. Further, the inner tube 11 may extend to the vicinity of the stent mount 12a and may be integrally continuous with the release receiving member 22.

[0075] In the delivery catheter 3C of the third embodiment (FIG. 9), the kink prevention member 32 may be integrally continuous with the inner tube 11. The kink prevention member 32 may be integrally continuous with the release receiving member 21. The inner tube 11, the kink prevention member 32, and the release receiving member 21 may be integrally continuous and may be configured by a single resin tube. In this case, a spiral slit 33 is formed in a range that becomes the mount proximal side portion 14 in the resin tube. In the delivery catheter 3C of the third embodiment (FIG. 9), the intermediate tube 13 may be omitted.

[0076] In the delivery catheter 3D of the fourth embodiment (FIG. 10), the outer diameter of the protection tube 34 is the same as the outer diameter of the inner tube 11, and the inner diameter of the protection tube 34 is larger than the inner diameter of the inner tube 11, whereby the protection tube 34 may be thinner than the inner tube 11. In the delivery catheter 4D of the fourth embodiment (FIG. 10) or a modified example thereof (FIG. 11), the protection tube 34 and the release receiving member 21 may be integrally connected, and further, the inner tube 11, the protection tube 34, and the release receiving member 21 may be formed of a single resin tube. In the delivery catheter 4D of the fourth embodiment (FIG. 10) or a modified example thereof (FIG. 11), the intermediate tube 13 may be omitted.

[0077] In the delivery catheter 4E of the fifth embodiment (FIG. 12), the intermediate tube 13 may be omitted.

Industrial Applicability

[0078] The present invention can be applied to a delivery catheter used to deliver a stent for expanding a stenotic portion of a body lumen to the stenotic portion.

Explanation of Reference Numerals

[0079] 1 Delivery system 2 Stent 3 Delivery catheter 3B to 3F Delivery catheter 4 Outer tube 6 Endoscope 6a Curved portion 10 Inner shaft 10d Step 10p Mount proximal position 11 Inner tube 12 Inner tube 12a Stent mount portion 13 Intermediate tube 14 Mount proximal portion 14a Resistance suppression portion 15 Adhesive filling area 16 Adhesive layer 16d Adhesive 20 Mount proximity piece 21 Release receiving member 21a Release receiving surface 22 Endoscope visual marker 24 Guide 30, 32 Kink prevention member 33 Helical slit 34 - 36 Protection tube (kink prevention member) 37 Common tube (kink prevention member) 37c Protection tube part

Claims

1. A delivery catheter for delivering a stent to a lesion site, comprising an inner tube and an inner shaft covered by the inner tube, wherein a distal end portion of the inner shaft extends beyond the inner tube to form a stent mounting portion, an outer tube through which the inner shaft is axially movable, and an adhesive filling region including an adhesive layer for bonding the inner tube and the inner shaft in the inner shaft is provided on the proximal side away from the stent mounting portion, and a mounting proximal side portion more flexible than the adhesive filling region is interposed between the stent mounting portion and the adhesive filling region. The delivery catheter is characterized by this.

2. The inner shaft further comprises an endoscope visual recognition marker close to the proximal side of the stent mounting portion, The delivery catheter according to claim 1, wherein a distal end of the inner tube is disposed on the proximal side of the endoscope visual recognition marker at a distance equal to the length of the mounting proximal side portion.

3. The inner shaft further includes an intermediate tube that straddles the adhesive filling region through the mounting proximal side portion from a position close to the proximal side of the stent mounting portion, and the inner tube is passed through the intermediate tube, The endoscope visual recognition marker is provided on an outer periphery of a distal end portion of the intermediate tube, The delivery catheter according to claim 2, wherein a proximal end portion of the intermediate tube is interposed between an inner periphery of a distal end portion of the inner tube and an outer periphery of the inner shaft and is bonded to the inner tube and the inner shaft through the adhesive layer.

4. An annular release receiving member is provided on an outer periphery of the distal end portion of the intermediate tube, and the endoscope visual recognition marker is provided on an outer periphery of the release receiving member, The delivery catheter according to claim 3, wherein a distal end face of the release receiving member constitutes a release receiving surface against which a proximal end of the stent can abut.

5. The delivery catheter according to claim 4, wherein a tapered guide portion that reduces in diameter from the release receiving member toward the proximal side is provided on an outer periphery of the intermediate tube.

6. The delivery catheter according to claim 5, wherein the guide portion is constituted by an adhesive that is integral with an adhesive layer interposed between the intermediate tube and the release receiving member.

7. The delivery catheter according to any one of claims 4 to 6, wherein the release receiving member is constituted by a resin tube having the same material and the same diameter as the inner tube.

8. The delivery catheter according to claim 3, wherein one or a plurality of annular kink prevention members are provided on the outer periphery of the intermediate tube at the proximal side portion of the mount, with intervals in the axial direction.

9. The delivery catheter according to claim 2, wherein a tubular kink prevention member that is more flexible than the inner tube and has an outer diameter equal to or smaller than the outer diameter of the inner tube is provided at the proximal side portion of the mount.

10. The delivery catheter according to claim 9, wherein the kink prevention member is in a spiral tubular shape.

11. The delivery catheter according to claim 9, wherein the kink prevention member has a smaller wall thickness than the inner tube.

12. The delivery catheter according to claim 9, wherein the kink prevention member has a lower hardness than the inner tube.

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