catheter

Abstract

This catheter is provided with a shaft part having a first shaft and a second shaft. The first shaft is a cylindrical member having a guide wire lumen into which a guide wire is inserted. The second shaft is shaped as a cylinder having an imaging lumen into which an imaging device for acquiring an image of the interior of a biological lumen is inserted, and is disposed alongside the first shaft. In a first region extending from a first position on the tip section of the shaft part to a second position located on the base end side relative to the first position, the second shaft is not joined to the first shaft, and in a second region that continues from the first region and that is located on the base end side relative to the first region, the second shaft is joined to the first shaft.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a catheter.

Background Art

[0002] Conventionally, in order to obtain clearer images in IVUS, a configuration has been known in which a large opening (a portion where no resin material exists) is provided at a position facing the transducer in a first shaft having a guide wire lumen (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional IVUS catheter, a second shaft is joined to a first shaft over the entire length. That is, even at the position where the transducer of the IVUS device is disposed, the second shaft is joined to the first shaft. Therefore, at the joint, transmission and reception of ultrasonic waves by the transducer of the IVUS device inserted into the IVUS lumen of the second shaft are hindered, and acquisition of clear images by the IVUS device is inhibited. More specifically, when the joint between the first shaft and the second shaft is realized using an adhesive, transmission and reception of ultrasonic waves on the first shaft side by the transducer are hindered due to the presence of the adhesive. Also, when the joint between the first shaft and the second shaft is realized by welding, distortion occurs in the shaft due to welding, and the range in which transmission and reception of ultrasonic waves on the first shaft side by the transducer are hindered increases. Thus, in a conventional IVUS catheter, there is room for improvement in terms of acquisition of clear images by the IVUS device.

[0005] Furthermore, these challenges are not limited to IVUS catheters having an IVUS lumen into which an IVUS device is inserted, but are common to catheters having an imaging lumen into which an imaging device for acquiring images of the inside of a biological lumen is inserted. [Means for solving the problem]

[0006] A catheter disclosed herein comprises a shaft portion having a first shaft and a second shaft. The first shaft is a tubular member having a guidewire lumen into which a guidewire is inserted. The second shaft is a tubular member having an imaging lumen into which an imaging device for acquiring images of a biological lumen is inserted, and is positioned alongside the first shaft. In a first region from a first position at the tip of the shaft portion to a second position located proximal to the first position, the second shaft is not joined to the first shaft, while in a second region continuous with the first region and located proximal to the first region, the second shaft is joined to the first shaft. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram schematically shows the configuration of the recanalization catheter system in the first embodiment. [Figure 2] Diagram illustrating the configuration of an IVUS catheter. [Figure 3] Diagram illustrating the configuration of an IVUS catheter. [Figure 4] Diagram illustrating the configuration of an IVUS catheter. [Figure 5] Diagram illustrating the configuration of an IVUS catheter. [Figure 6] Diagram illustrating the configuration of an IVUS catheter. [Figure 7] An explanatory diagram showing an example of how to use an IVUS catheter. [Figure 8] An explanatory diagram showing another example of how an IVUS catheter is used. [Figure 9]A schematic diagram illustrating the configuration of an IVUS device. [Figure 10] An explanatory diagram showing an example of how to use the recanalization catheter system. [Figure 11] An explanatory diagram showing an example of how to use the recanalization catheter system. [Figure 12] This diagram schematically shows the configuration of the IVUS catheter in the second embodiment. [Figure 13] This diagram schematically shows the configuration of the IVUS catheter in the third embodiment. [Modes for carrying out the invention]

[0008] A. First Embodiment: A-1. Configuration of the recanalization catheter system 10: Figure 1 is a schematic diagram illustrating the configuration of the recanalization catheter system 10 in the first embodiment. The recanalization catheter system 10 is used, for example, when treating a CTO (cardiac tumor) in a blood vessel using an antegrade approach. The recanalization catheter system 10 comprises an IVUS catheter 100, an IVUS device 200, and an imaging console 300.

[0009] Note that in Figure 1, a portion of the recanalization catheter system 10 is omitted from the illustration. Also, Figure 1 shows mutually orthogonal XYZ axes. In devices such as the IVUS catheter 100, the positive Z-axis side is the tip side (distal side) that is inserted into the body, and the negative Z-axis side is the proximal end (proximal side) that is manipulated by a physician or other operator. Also, in Figure 1, the IVUS catheter 100 is shown in a state that is approximately straight parallel to the Z-axis direction, but the IVUS catheter 100 has enough flexibility to be bent. These points are the same in subsequent figures. In this specification, for the recanalization catheter system 10 and its components, the tip end is referred to as the "tip," the tip and its vicinity as the "tip portion," the proximal end is referred to as the "proximal end," and the proximal end and its vicinity as the "proximal end portion."

[0010] (Components of IVUS catheter 100) Figures 2 to 6 are explanatory diagrams showing the configuration of the IVUS catheter 100. Figure 2 shows an enlarged view of the side configuration of the tip of the IVUS catheter 100, Figure 3 shows an enlarged view of the side (bottom) configuration of the IVUS catheter 100 as seen from direction A in Figure 2, Figure 4 shows the cross-sectional configuration of the IVUS catheter 100 at the IV-IV position in Figure 2, Figure 5 shows the cross-sectional configuration of the IVUS catheter 100 at the VV position in Figure 2, and Figure 6 shows the cross-sectional configuration of the IVUS catheter 100 at the VI-VI position in Figure 2.

[0011] The IVUS catheter 100 is a long medical device used when performing IVUS, a technique for acquiring images of the inside of a living lumen such as a blood vessel. The IVUS catheter 100 has a long shaft portion 110. As shown in Figure 2, the shaft portion 110 includes a first inner shaft 111, a second inner shaft 112, and an outer shaft 113. The first inner shaft 111 is an example of the first shaft in the claims, and the second inner shaft 112 is an example of the second shaft in the claims.

[0012] The second inner shaft 112 is a substantially cylindrical member having an IVUS lumen 160L into which the IVUS device 200 is inserted. A second tip opening 110b is formed at the tip of the second inner shaft 112, which connects the IVUS lumen 160L to the outside, and a second base opening 110d is formed at the base end of the second inner shaft 112, which also connects the IVUS lumen 160L to the outside (Figure 1). The second tip opening 110b is an opening for discharging fluid injected into the IVUS lumen 160L from the second base opening 110d. The second tip opening 110b does not need to be formed at the tip of the second inner shaft 112, but may be formed at the tip portion of the second inner shaft 112. The IVUS lumen 160L is an example of an imaging lumen in the claims.

[0013] The first inner shaft 111 is a substantially cylindrical member having a guide wire lumen 150L into which a guide wire is inserted. A tip first opening 110a that communicates the guide wire lumen 150L with the outside is formed at the tip of the first inner shaft 111, and a base first opening 110c that communicates the guide wire lumen 150L with the outside is formed at the base end of the first inner shaft 111 (FIG. 1).

[0014] The first inner shaft 111 and the second inner shaft 112 are arranged side by side in the Y-axis direction with their extending directions parallel to each other. As shown in FIG. 2, the foremost end portion of the first inner shaft 111 (hereinafter referred to as "protrusion 115") protrudes to the tip side of the third position P3 which is the position of the tip of the second inner shaft 112. Therefore, the tip first opening 110a is located on the tip side of the tip second opening 110b. Further, the tip end portion of the second inner shaft 112 has an outer diameter that gradually decreases from the base end side toward the tip end side, and the tip end surface has a shape that smoothly connects to the protrusion 115 of the first inner shaft 111.

[0015] A tip chip 120 is joined to at least a part of the protrusion 115 of the first inner shaft 111. The tip chip 120 is formed of, for example, a material having radiopacity. The shape of the tip chip 120 can be arbitrarily set, and for example, it can be a substantially cylindrical shape with an R attached to the tip end portion, or a substantially frustum-shaped cone whose outer diameter gradually decreases from the base end side toward the tip end side.

[0016] The second inner shaft 112 is joined to the first inner shaft 111 in a part along its extending direction and is not joined to the first inner shaft 111 in the remaining part. More specifically, as shown in FIG. 2, in a part on the distal end side in the shaft portion 110, specifically, in a first region R1 from a first position P1 located on the proximal end side of the distal end of the second inner shaft 112 to a second position P2 located on the proximal end side of the first position P1, the second inner shaft 112 is not joined to the first inner shaft 111. Note that the length of the first region R1 along the extending direction of the shaft portion 110 can be, for example, from 10 mm to 30 mm. On the other hand, in a second region R2 that is continuous with the first region R1 and is located on the proximal end side of the first region R1, specifically, in a region from the second position P2 to the proximal end of the second inner shaft 112, the second inner shaft 112 is joined to the first inner shaft 111. Also, in a third region R3 that is continuous with the first region R1 and is located on the distal end side of the first region R1, specifically, in a region from the first position P1 to a third position P3 that is the distal end of the second inner shaft 112, the second inner shaft 112 is joined to the first inner shaft 111. Thus, in the IVUS catheter 100 of the present embodiment, three parts, namely, a joined part where the second inner shaft 112 is joined to the first inner shaft 111, a non-joined part where the second inner shaft 112 is not joined to the first inner shaft 111, and another joined part where the second inner shaft 112 is joined to the first inner shaft 111, are arranged in order from the distal end side to the proximal end side.

[0017] For joining the first inner shaft 111 and the second inner shaft 112, joining of resins by thermal melting (welding) or joining with an insulating adhesive such as epoxy adhesive can be employed. In this embodiment, the joining of the first inner shaft 111 and the second inner shaft 112 is achieved by welding. Therefore, in the first region R1 where the first inner shaft 111 and the second inner shaft 112 are not joined, the cross-sections of both are close to a perfect circle as shown in Figure 4, whereas in the second region R2 where they are joined, the cross-sections of both are distorted into a flattened shape due to welding, as shown in Figures 5 and 6.

[0018] As shown in Figures 4 to 6, the second inner shaft 112 has a single-layer structure along its entire length. On the other hand, the first inner shaft 111 has a single-layer structure consisting only of the first layer 111a in the third region R3 and the first region R1, but has a two-layer structure consisting of the first layer 111a and the second layer 111b in the second region R2. In this embodiment, the thickness t111a of the first layer 111a is approximately the same as the thickness t111b of the second layer 111b.

[0019] As shown in Figure 6, the outer shaft 113 is a substantially elliptical cylindrical member. The first inner shaft 111 and the second inner shaft 112 are housed in the internal space of the outer shaft 113. A filler material 116 is filled around the first inner shaft 111 and the second inner shaft 112 in the internal space of the outer shaft 113, thereby fixing the first inner shaft 111 and the second inner shaft 112 in place. As shown in Figure 2, the tip of the outer shaft 113 is located at the fourth position P4, which is closer to the base end than the second position P2. That is, the outer shaft 113 does not cover the first inner shaft 111 and the second inner shaft 112 in the fourth region R4, which is the area from the third position P3 to the fourth position P4, and covers the first inner shaft 111 and the second inner shaft 112 in the fifth region R5, which is continuous with the fourth region R4 and located closer to the base end than the fourth region R4. The fourth region R4 is the region that encompasses the first region R1. In the following, the region of the fourth region R4 from the third position P3 to the second position P2 will be called the first sub-region R41, and the region from the second position P2 to the fourth position P4 will be called the second sub-region R42.

[0020] In the IVUS catheter 100 of this embodiment, the minimum wall thickness of the shaft portion 110 at the position of the guidewire lumen 150L differs depending on the position along the extension direction. Here, the minimum wall thickness of the shaft portion 110 at the position of the guidewire lumen 150L is the shortest distance from the inner circumferential surface of the guidewire lumen 150L to the outer circumferential surface of the shaft portion 110 in the cross-section of the shaft portion 110 (see Figures 4 to 6), and is hereinafter referred to as the "minimum wall thickness of the shaft portion on the guidewire lumen side". Specifically, in the first sub-region R41 of the fourth region R4 (third region R3 and first region R1), as shown in Figure 4, the minimum wall thickness t41 of the shaft portion on the guidewire lumen side coincides with the wall thickness t111a of the first layer 111a of the first inner shaft 111. Furthermore, in the second sub-region R42 of the fourth region R4, as shown in Figure 5, the minimum wall thickness t42 of the guidewire lumen-side shaft portion is equal to the sum of the wall thickness t111a of the first layer 111a and the wall thickness t111b of the second layer 111b of the first inner shaft 111. Also, in the fifth region R5, as shown in Figure 6, the minimum wall thickness t5 of the guidewire lumen-side shaft portion is equal to the sum of the wall thickness t111a of the first layer 111a, the wall thickness t111b of the second layer 111b, and the wall thickness t113 of the outer shaft 113. Therefore, the minimum wall thickness of the guidewire lumen-side shaft portion increases in the order of the first sub-region R41, the second sub-region R42, and the fifth region R5. In other words, the minimum wall thickness of the guidewire lumen-side shaft portion gradually increases from the tip side to the base side.

[0021] As shown in Figures 2 and 3, the first inner shaft 111 has a notch 130 that connects the guidewire lumen 150L to the outside. The notch 130 is located in the second region R2 (more specifically, the second sub-region R42) described above. The notch 130 is formed on the side surface of the first inner shaft 111, on the opposite side from the IVUS lumen 160L, with respect to the central axis O of the guidewire lumen 150L. As shown in Figure 3, the notch 130 has a substantially elliptical shape with the extension direction of the first inner shaft 111 (Z-axis direction) as its major axis when viewed in the direction in which the guidewire lumen 150L and the IVUS lumen 160L are aligned (Y-axis direction). Near the notch 130 (on the tip side of the notch 130 in this embodiment), a marker 141 made of, for example, a radiopaque material is provided.

[0022] The IVUS lumen 160L formed in the second inner shaft 112 extends along the central axis of the second inner shaft 112 from its tip to its base. On the other hand, as shown in Figure 3, the guidewire lumen 150L formed in the first inner shaft 111 similarly extends along the central axis of the first inner shaft 111 from its tip to its base, but branches off at an intermediate position (for example, about 200mm to 400mm from the tip) and communicates with the outside via a port 110e formed on the side of the shaft portion 110. Hereinafter, the lumen that branches off from the guidewire lumen 150L and connects to the port 110e will be referred to as the "branched lumen 150Lb". Furthermore, the area around the connection point between the guidewire lumen 150L and the branched lumen 150Lb within the shaft portion 110 will be referred to as the "branch portion 150".

[0023] The branching section 150 has a large diameter section 151, a raised section 152, and a boundary wall 153. The large diameter section 151 is the part with a larger inner diameter compared to the rest of the guide wire lumen 150L. The raised section 152 is a raised portion of the inner circumferential surface 152i of the branching section 150 that defines the guide wire lumen 150L. The raised section 152 is located on the tip side of the inner circumferential surface 152i of the branching section 150, compared to the large diameter section 151. In the raised section 152, the inner circumferential surface 152i of the branching section 150 is raised toward the side where the branched lumen 150Lb extends. The boundary wall 153 is a part of the shaft section 110 located on the base end side of the large diameter section 151, and separates the guide wire lumen 150L from the branched lumen 150Lb. The tip A1 of boundary wall 153 is located further forward than the tip A2 of port 110e.

[0024] Figure 7 is an explanatory diagram showing an example of how the IVUS catheter 100 is used. Column (A) of Figure 7 shows a side view of the IVUS catheter 100 viewed from the same direction as in Figure 2, and column (B) of Figure 7 shows a side (bottom) view of the IVUS catheter 100 viewed from the same direction as in Figure 3. Figure 7 shows how the IVUS catheter 100 is used when the delivery guidewire 70, used for delivery of the IVUS catheter 100, is inserted into the guidewire lumen 150L from the first tip opening 110a and advances from the tip to the proximal end within the guidewire lumen 150L (in other words, when the IVUS catheter 100 is used as a rapid exchange type (Rx type) catheter, hereinafter referred to as "the first case").

[0025] In the first case, the operator inserts the proximal end of the delivery guidewire 70 into the guidewire lumen 150L through the first tip opening 110a of the IVUS catheter 100 and withdraws it to the outside through the branch lumen 150Lb and port 110e. At this time, the proximal end of the delivery guidewire 70 comes into contact with the raised portion 152, which naturally guides it toward the branch lumen 150Lb (moving in the direction of the thick arrow).

[0026] Figure 8 is an explanatory diagram showing another example of how the IVUS catheter 100 is used. Column (A) of Figure 8 shows a side view of the IVUS catheter 100 viewed from the same direction as in Figure 2, and column (B) of Figure 8 shows a side (bottom) view of the IVUS catheter 100 viewed from the same direction as in Figure 3. Figure 8 shows how the IVUS catheter 100 is used, for example, when a penetrating guidewire 400 used to penetrate a CTO lesion is inserted into the guidewire lumen 150L from the proximal first opening 110c (Figure 1) and advances from the proximal end to the distal end within the guidewire lumen 150L (in other words, when the IVUS catheter 100 is used as an over-the-wire (OTW) type catheter, hereinafter referred to as "the second case").

[0027] In the second case, the surgeon inserts the tip of the penetrating guidewire 400 into the guidewire lumen 150L through the proximal first opening 110c, guides it straight through the branching section 150 (without causing the penetrating guidewire 400 to wander into the branching lumen 150Lb), and pulls it out to the outside through the notch 130. At this time, the tip of the penetrating guidewire 400 comes into contact with the boundary wall 153, which guides it to naturally pass through the branching section 150 (moving in the direction of the thick arrow).

[0028] Returning to Figure 1, let's continue the explanation. The IVUS catheter 100 is further equipped with a regulator 105. The regulator 105 is the part that controls the forward or backward movement of the IVUS device 200 in the IVUS lumen 160L. The regulator 105 is equipped with a dial that can be operated by the operator, for example, and when the dial is rotated, the IVUS device 200 moves forward or backward.

[0029] The outer shaft 113, the first inner shaft 111, the second inner shaft 112, the filler 116, and the regulator 105 can be formed from known materials such as nylon resins like polyamide, polyethylene, polypropylene, polyolefins such as ethylene-propylene copolymer, polyesters such as polyethylene terephthalate, thermoplastic resins such as polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer, and polyurethane, polyamide elastomers, polyolefin elastomers, polyurethane elastomers, silicone rubber, and latex rubber. The outer shaft 113, the first inner shaft 111, the second inner shaft 112, the filler 116, and the regulator 105 may be formed from the same material, or at least a part or all of them may be formed from different materials. It is preferable that at least a portion of the outer shaft 113, the first inner shaft 111, the second inner shaft 112, and the filler 116 located near the notch 130 be formed from a resin with a small difference in acoustic impedance with biological tissue, such as polyethylene.

[0030] (Configuration of IVUS device 200, etc.) Figure 9 is a schematic diagram illustrating the configuration of the IVUS device 200. The IVUS device 200 is a device for acquiring images within a biological lumen and has an overall elongated shape. The IVUS device 200 is an example of an imaging device within the claims.

[0031] The IVUS device 200 includes a transducer 201, a driving cable 202, a connector 203, and a motor drive 204.

[0032] The transducer 201 has an ultrasonic probe (also called an ultrasonic transducer, piezoelectric element, ultrasonic transmitting / receiving element, or ultrasonic element) that emits ultrasonic waves and receives the reflected waves. The motor drive 204 is a device for controlling the rotation of the transducer 201. The motor drive 204 is electrically connected to the imaging console 300 via a cable 50 (Figure 1). The driving cable 202 is a long member and has a coaxial cable that electrically connects the transducer 201 and the motor drive 204. The connector 203 is a member for connecting the coaxial cable of the driving cable 202 to the motor drive 204.

[0033] The imaging console 300 (Figure 1) controls the IVUS device 200 and generates and displays images based on signals received from the IVUS device 200. Specifically, the imaging console 300 moves the transducer 201 in the IVUS lumen 160L in the extension direction (Z-axis direction) of the shaft 110 and rotates it in the circumferential direction of the shaft 110 in response to the operation of the controller 105. The range of movement of the transducer 201 along the extension direction of the shaft 110 can be set, for example, from the tip of the second inner shaft 112 to a position approximately 100 mm to 200 mm away from that tip. The imaging console 300 also causes the transducer 201 to transmit and receive ultrasound waves in response to the operator's operation via an input means (not shown). The reflected waves received by the transducer 201 are input to the imaging console 300 via the driving cable 202 and cable 50. The imaging console 300 generates an image represented by grayscale tones corresponding to the intensity of the received reflected wave, and displays the generated image on the display 302. Hereafter, the image acquired by the IVUS device 200 and displayed on the display 302 is also referred to as the "sensor image".

[0034] (How to use the recanalization catheter system 10) Figures 10 and 11 are explanatory diagrams illustrating an example of how to use the recanalization catheter system 10. Figures 10 and 11 show a coronary artery 80 as an example of a biological lumen, a CTO 81 occurring in the coronary artery 80, the true lumen 84, the false lumen 82 formed in or beneath the intima of the coronary artery 80 (all dissection lumens other than the true lumen 84 formed by a medical device such as a delivery guidewire 70), and a fibrous capsule (plaque) 83 present between the true lumen 84 and the false lumen 82. The fibrous capsule 83 may form in a fibrous manner on the surface of the CTO lesion.

[0035] Column (A) of Figure 10 shows the insertion of the delivery guidewire 70 into the coronary artery 80. In Column (A) of Figure 10, the delivery guidewire 70, manipulated by the operator, has become lost in the intima of the coronary artery 80, or is forming a false lumen 82 beneath the intima.

[0036] Column (B) of Figure 10 shows the delivery of the IVUS catheter 100 using the delivery guidewire 70. The operator inserts the delivery guidewire 70 into the IVUS catheter 100 by performing the procedure described above with reference to Figure 7. Then, the operator uses the delivery guidewire 70 as a guide to deliver the IVUS catheter 100 to the false lumen 82. At this time, the transducer 201 of the IVUS device 200 is positioned in the first region R1 of the IVUS catheter 100.

[0037] Column (A) in Figure 11 shows the adjustment of the positions of the delivered IVUS catheter 100 and IVUS device 200. The operator adjusts the positions as shown in a1 to a3 below. Adjustment a2 may be omitted.

[0038] (Adjustment a1: Adjustment of the position of the IVUS catheter 100 along the extension direction) The operator moves the IVUS catheter 100 along the coronary artery 80 to position the notch 130 of the IVUS catheter 100 in the optimal location for penetration into the true lumen 84 by the penetrating guidewire 400. Adjustment a1 can be performed while confirming the position of the coronary artery 80 on the sensor image or the position of the marker 141 on the X-ray image. This adjustment is performed, for example, so that the first region R1 of the IVUS catheter 100 is at the position of the tip of the CTO 81, in order to make it easier to confirm the position to be penetrated by the penetrating guidewire 400 pulled out from the notch 130 (the position of the tip of the CTO 81) using the sensor image. At this time, by referring to the sensor image based on the signal from the transducer 201 located in the first region R1, the position of the IVUS catheter 100 along the extension direction can be precisely adjusted so that the first region R1 is at the position of the tip of the CTO 81, while confirming the position of the tip of the CTO 81.

[0039] (Adjustment a2: Adjustment of the orientation of the IVUS catheter 100 along the circumferential direction) The operator rotates the IVUS catheter 100 circumferentially to adjust its orientation so that the notch 130 faces the CTO 81. Adjustment a2 can be performed while confirming the positional relationship between the delivery guidewire 70 and the coronary artery 80 on the sensor image.

[0040] (Adjustment a3: Adjustment of the longitudinal position of transducer 201 of IVUS device 200) The operator moves the transducer 201 by manipulating the adjuster 105 so that it is in a position suitable for observing the penetration of the guidewire 400. Adjustment a3 can be performed while confirming the coronary artery 80 on the sensor image.

[0041] Column (B) in Figure 11 shows how the penetrating guidewire 400 penetrates biological tissue. The penetrating guidewire 400 is a long medical device with a pointed tip. The pointed tip of the penetrating guidewire 400 is an arrowhead or wedge-shaped portion that tapers in diameter from the proximal end to the tip, enabling the penetrating guidewire 400 to penetrate biological tissue.

[0042] First, the operator removes the delivery guidewire 70. After removing the delivery guidewire 70, the operator inserts the penetration guidewire 400 into the IVUS catheter 100 by performing the above-described procedure with reference to Figure 8. Then, while confirming the position of the penetration guidewire 400 on the sensor image, the operator guides the pointed end of the penetration guidewire 400 to the optimal site for penetration as described above. Then, the pointed end of the penetration guidewire 400 is used to penetrate the biological tissue (target tissue), and the tip of the penetration guidewire 400 reaches the true lumen 84. At this time, in order to make it easier to confirm the penetration position by the penetration guidewire 400 on the sensor image, the transducer 201 of the IVUS device 200 is positioned in the first region R1 of the IVUS catheter 100.

[0043] This method enables the recanalization catheter system 10 to open the CTO 81. It should be noted that the method described above is merely one example, and the recanalization catheter system 10 can be used in various procedures. For example, the recanalization catheter system 10 may be used not only for approaches from the false lumen 82 to the true lumen 84, but also for approaches that penetrate the CTO from the proximal true lumen 84 to the distal true lumen 84.

[0044] A-2. Effects of the first embodiment: As described above, the IVUS catheter 100 of this embodiment comprises a shaft portion 110 having a first inner shaft 111 and a second inner shaft 112. The first inner shaft 111 is a cylindrical member having a guidewire lumen 150L into which a guidewire is inserted. The second inner shaft 112 is a cylindrical member having an IVUS lumen 160L into which an IVUS device 200 is inserted, and is arranged alongside the first inner shaft 111. In the first region R1 from a first position P1 at the tip of the shaft portion 110 to a second position P2 located more proximal to the first position P1, the second inner shaft 112 is not joined to the first inner shaft 111. In the second region R2, which is continuous with the first region R1 and located more proximal to the first region R1, the second inner shaft 112 is joined to the first inner shaft 111.

[0045] Thus, in the IVUS catheter 100 of this embodiment, there is a first region R1 at the tip of the shaft portion 110 in which the second inner shaft 112 is not joined to the first inner shaft 111. In this first region R1, there is no adhesive for joining the first inner shaft 111 and the second inner shaft 112, and no distortion due to thermal welding occurs in the first inner shaft 111 and the second inner shaft 112. Therefore, when the transducer 201 of the IVUS device 200 is positioned in the first region R1, the presence of adhesive does not hinder the transmission and reception of ultrasound on the first inner shaft 111 side by the transducer 201. Furthermore, as shown in Figure 4, since no welding-induced distortion occurs in the first inner shaft 111 in the first region R1, the range in which the transmission and reception of ultrasound on the first inner shaft 111 side by the transducer 201 of the IVUS device 200 is obstructed (the range of angle θ1 shown in Figures 4 and 5) is narrower compared to the area in the first inner shaft 111 where welding-induced distortion occurs, as shown in the second region R2 in Figure 5. Therefore, with the IVUS catheter 100 of this embodiment, the obstruction of the transmission and reception of ultrasound on the first inner shaft 111 side by the transducer 201 due to the joint between the first inner shaft 111 and the second inner shaft 112 is avoided, and clearer images can be obtained by the IVUS device 200.

[0046] For example, as described above, when the IVUS catheter 100 is delivered or when the penetration guide wire 400 is used for penetration, if the transducer 201 is positioned in the first region R1 of the IVUS catheter 100, the position of the tip of the CTO 81 can be accurately confirmed by referring to the sensor image based on the signal from the transducer 201 located in the first region R1, thereby enabling the IVUS catheter 100 to be delivered to the appropriate position. Furthermore, the penetration position by the penetration guide wire 400 and whether or not the penetration guide wire 400 has successfully penetrated the CTO 81 can be accurately confirmed.

[0047] Furthermore, according to the IVUS catheter 100 of this embodiment, the flexibility of the shaft portion 110 can be improved at the tip of the shaft portion 110, which tends to harden when the IVUS device 200 is inserted, due to the presence of a first region R1 in which the second inner shaft 112 is not joined to the first inner shaft 111, even though flexibility is required for the shaft portion 110. This improves the operability of the IVUS catheter 100.

[0048] Furthermore, according to the IVUS catheter 100 of this embodiment, compared to the conventional configuration in which a large opening (a portion without resin material) is provided at a position facing the transducer 201 in the first inner shaft in order to acquire clearer images, the rigidity gap of the shaft portion 110 can be reduced, and the kink resistance of the shaft portion 110 can be improved.

[0049] Furthermore, in the IVUS catheter 100 of this embodiment, the first position P1 is located proximal to the tip of the second inner shaft 112, and in the third region R3, which is continuous with the first region R1 and located more distal to the first region R1, the second inner shaft 112 is joined to the first inner shaft 111. Therefore, with the IVUS catheter 100 of this embodiment, the presence of the first region R1, where the second inner shaft 112 is not joined to the first inner shaft 111, enables the acquisition of clearer images, while the presence of the third region R3, located more distal to the first region R1 and where the second inner shaft 112 is joined to the first inner shaft 111, suppresses the decrease in operability of the shaft portion 110 caused by the provision of the unjoined first region R1.

[0050] Furthermore, in the IVUS catheter 100 of this embodiment, the minimum wall thickness of the guidewire lumen-side shaft portion in the fourth region R4, which encompasses the first region R1, is smaller than the minimum wall thickness of the guidewire lumen-side shaft portion in the fifth region R5, which is continuous with the fourth region R4 and located more proximal to the fourth region R4. Therefore, when the transducer 201 is located in a portion of the fourth region R4 other than the first region R1, even if it is not in the first region R1, interference with the transmission and reception of ultrasound on the first inner shaft 111 side by the transducer 201 is suppressed compared to when the transducer 201 is located in the fifth region R5. Accordingly, with the IVUS catheter 100 of this embodiment, by positioning the transducer 201 in the fourth region R4, interference with the transmission and reception of ultrasound on the first inner shaft 111 side (guidewire lumen 150L side) by the transducer 201 can be more effectively avoided, and even clearer images can be acquired by the IVUS device 200.

[0051] For example, when delivering the IVUS catheter 100 or when penetrating with the penetration guidewire 400, even if the transducer 201 is positioned in a part of the fourth region R4 other than the first region R1, the position of the tip of the CTO 81 can be accurately confirmed by referring to the sensor image based on the signal from the transducer 201, allowing the IVUS catheter 100 to be delivered to the appropriate position. Furthermore, the penetration position by the penetration guidewire 400 and whether the penetration guidewire 400 has reliably penetrated the CTO 81 can be accurately confirmed.

[0052] Furthermore, in the IVUS catheter 100 of this embodiment, the fourth region R4 consists of a first sub-region R41 and a second sub-region R42 that is continuous with the first sub-region R41 and located more proximal to the first sub-region R41. The minimum wall thickness of the guidewire lumen-side shaft portion in the second sub-region R42 is greater than the minimum wall thickness of the guidewire lumen-side shaft portion in the first sub-region R41. Therefore, the IVUS catheter 100 of this embodiment can increase the rigidity of the shaft portion 110 in the second sub-region R42, ensuring rigidity when advancing through curved sections within blood vessels, for example. In addition, the rigidity of the shaft portion 110 can be gradually reduced in the order of the fifth region R5, the second sub-region R42, and the first sub-region R41, which are arranged from the proximal to the distal end, effectively reducing the rigidity gap and effectively improving the kink resistance of the shaft portion 110.

[0053] B. Second Embodiment: Figure 12 is an explanatory diagram schematically showing the configuration of the IVUS catheter 100a in the second embodiment. In the following, for the configuration of the IVUS catheter 100a in the second embodiment that is the same as that of the IVUS catheter 100 in the first embodiment described above, the same reference numerals are used and their explanations are omitted as appropriate.

[0054] In the IVUS catheter 100a of the second embodiment, the position of the first region R1 where the second inner shaft 112 is not joined to the first inner shaft 111 differs from that of the IVUS catheter 100 of the first embodiment. Specifically, in the IVUS catheter 100a of the second embodiment, the first region R1 is set to encompass a portion of the tip of the notch 130 formed in the shaft portion 110. That is, in the IVUS catheter 100a of the second embodiment, the second inner shaft 112 is not joined to the first inner shaft 111 at a portion of the tip of the notch 130. Therefore, the IVUS device 200 can acquire a clear image near the notch 130. Accordingly, with the IVUS catheter 100a of the second embodiment, when withdrawing the tip of the penetrating guidewire 400 from the notch 130, the procedure can be performed by referring to a clear image acquired by the IVUS device 200, thereby improving convenience.

[0055] C. Third Embodiment: Figure 13 is a schematic diagram illustrating the configuration of the IVUS catheter 100b in the third embodiment. In the following, for the configuration of the IVUS catheter 100b in the third embodiment that is the same as that of the IVUS catheter 100 in the first embodiment described above, the same reference numerals are used, and their explanations will be omitted as appropriate.

[0056] The IVUS catheter 100b of the third embodiment differs from the IVUS catheter 100 of the first embodiment in that it has three lumens. Specifically, the shaft portion 110 of the IVUS catheter 100b of the third embodiment includes a first inner shaft 111 having a guidewire lumen (delivery guidewire lumen) 150L into which a delivery guidewire 70 (see Figure 7) is inserted, a second inner shaft 112 having an IVUS lumen 160L into which an IVUS device 200 is inserted, and a third inner shaft 30 having a guidewire lumen (through guidewire lumen) 170L into which a through guidewire 400 (see Figure 8) is inserted. The third inner shaft 30 is an example of the third shaft in the claims.

[0057] The third inner shaft 30 is a substantially cylindrical member. The tip of the third inner shaft 30 is located closer to the base end than the tips of the first inner shaft 111 and the second inner shaft 112. A third tip opening 30a is formed at the tip of the third inner shaft 30, which connects the guide wire lumen 170L to the outside. The first inner shaft 111, the second inner shaft 112, and the third inner shaft 30 are arranged side by side with their extension directions parallel to each other and are housed in the internal space of the outer shaft 113. In this embodiment, the first inner shaft 111 does not have a notch 130.

[0058] In the IVUS catheter 100b of the third embodiment, similar to the IVUS catheter 100 of the first embodiment, in the first region R1 from the first position P1 at the tip of the shaft portion 110 to the second position P2 located proximal to the first position P1, the second inner shaft 112 is not joined to the first inner shaft 111. In the second region R2, which is continuous with the first region R1 and located proximal to the first region R1, the second inner shaft 112 is joined to the first inner shaft 111. Therefore, according to the IVUS catheter 100b of the third embodiment, interference with the transmission and reception of ultrasound on the first inner shaft 111 side by the transducer 201 due to the joining of the first inner shaft 111 and the second inner shaft 112 is avoided, and clearer images can be acquired by the IVUS device 200.

[0059] Furthermore, in the IVUS catheter 100b of the third embodiment, similar to the IVUS catheter 100 of the first embodiment, the first position P1 is located proximal to the tip of the second inner shaft 112, and in the third region R3, which is continuous with the first region R1 and located more distal to the first region R1, the second inner shaft 112 is joined to the first inner shaft 111. Therefore, according to the IVUS catheter 100b of the third embodiment, the presence of the first region R1, where the second inner shaft 112 is not joined to the first inner shaft 111, enables the acquisition of clearer images, while the presence of the third region R3, located more distal to the first region R1 and where the second inner shaft 112 is joined to the first inner shaft 111, suppresses the decrease in operability of the shaft portion 110 caused by the provision of the unjoined first region R1.

[0060] D. Variations: The technologies disclosed herein are not limited to the embodiments described above and can be modified in various forms without departing from their essence, for example, the following modifications are possible.

[0061] The configuration of the recanalization catheter system 10 and the IVUS catheter 100 and other devices that constitute it in the above embodiment is merely an example and can be modified in various ways. For example, in the above embodiment, a third region R3 exists where the second inner shaft 112 and the first inner shaft 111 are joined, located at the tip of the first region R1 where the second inner shaft 112 is not joined. However, the third region R3 may not exist, and the tip of the second inner shaft 112 may not be joined to the first inner shaft 111.

[0062] In the above embodiment, the minimum wall thickness of the guidewire lumen-side shaft in the second small region R42 is greater than the minimum wall thickness of the guidewire lumen-side shaft in the first small region R41, but the relationship between the two may be reversed or they may be the same. Also, in the above embodiment, the minimum wall thickness of the guidewire lumen-side shaft in the fourth region R4 is smaller than the minimum wall thickness of the guidewire lumen-side shaft in the fifth region R5, but the relationship between the two may be reversed or they may be the same.

[0063] In the above embodiment, the first inner shaft 111 and the second inner shaft 112 are formed from a single cylindrical body from the tip to the base end, but the first inner shaft 111 and / or the second inner shaft 112 may have a configuration in which multiple cylindrical bodies aligned in the extension direction are joined together. Also, in the above embodiment, the first inner shaft 111 and the second inner shaft 112 are covered by an outer shaft 113, but the outer shaft 113 may be omitted.

[0064] In the above embodiment, a notch 130 is formed in the IVUS catheter 100, but the notch 130 may not be formed. Also, in the above embodiment, a raised portion 152 and a boundary wall 153 are formed in the branch portion 150 of the IVUS catheter 100, but the raised portion 152 and / or boundary wall 153 may not be formed. Also, in the above embodiment, a branch lumen 150Lb branching from the guidewire lumen 150L is formed in the IVUS catheter 100, but the branch lumen 150Lb may not be formed.

[0065] In the above embodiment, an IVUS device 200 is used as the imaging device, but other imaging devices such as an OCT (Optical Coherence Tomography) device or a camera may be used instead of the IVUS device 200.

[0066] In the above embodiment, the recanalization catheter system 10 is described as a system for the use of a penetrating guidewire 400, but it may also be configured as a system to open a CTO using a plasma guidewire that performs plasma-assisted ablation of biological tissue, without using a penetrating guidewire 400. Furthermore, the recanalization catheter system 10 may be used in other ways not described above. For example, the recanalization catheter system 10 may be used in blood vessels other than coronary arteries (e.g., cerebral blood vessels), in biological tubular lumen other than blood vessels, or for treatments or examinations other than CTO opening.

Claims

1. It is a catheter, A cylindrical first shaft having a guidewire lumen into which a guidewire is inserted, It is cylindrical in shape and has an imaging lumen into which an imaging device for acquiring images of the inside of a biological lumen is inserted, and a second shaft is arranged alongside the first shaft, It has a shaft portion having the following In the first region from the first position at the tip of the shaft portion to the second position located closer to the base end than the first position, the second shaft is not joined to the first shaft, and in the second region which is continuous with the first region and located closer to the base end than the first region, the second shaft is joined to the first shaft. A notch is formed in the first shaft at a position closer to the base end than the tip, which communicates with the guide wire lumen. The first region in the shaft portion is a region that includes at least a part of the notch. catheter.

2. A catheter according to claim 1, The minimum thickness of the shaft portion at the position of the guide wire lumen in the fourth region encompassing the first region is smaller than the minimum thickness of the shaft portion at the position of the guide wire lumen in the fifth region which is continuous with the fourth region and located closer to the base end than the fourth region. catheter.

3. A catheter according to claim 2, The fourth region in the shaft portion consists of a first subregion and a second subregion that is continuous with the first subregion and located closer to the base end than the first subregion. The minimum thickness of the shaft portion at the position of the guide wire lumen in the second small region is greater than the minimum thickness of the shaft portion at the position of the guide wire lumen in the first small region. catheter.

4. A catheter according to any one of claims 1 to 3, The first position is located on the proximal end side of the tip of the second shaft. In the third region of the shaft portion, which is continuous with the first region and located closer to the tip than the first region, the second shaft is joined to the first shaft. catheter.

Images