dilator

Abstract

To provide a dilator that allows for the injection of contrast agent while suppressing deformation. [Solution] The dilator comprises a shaft 12 having a lumen through which a guide wire can be inserted. At least a portion of the tip 18 of the shaft 12 has a non-circular lumen 28.

Description

TECHNICAL FIELD

[0001] The present invention relates to a dilator. BACKGROUND ART

[0002] For the treatment of arrhythmia, a procedure is known in which an ablation catheter is percutaneously inserted into the left atrium to ablate (cauterize) the signal transmission pathway that causes arrhythmia. When performing ablation in the left atrium, a procedure called transseptal puncture (Brockenbrough technique) is sometimes performed, which creates a hole in the interatrial septum that separates the right atrium and the left atrium, so that the ablation catheter can be inserted from the right atrium side into the left atrium. Regarding this transseptal puncture, for example, Patent Document 1 discloses a transseptal puncture device that forms a through hole by applying high-frequency waves to the interatrial septum. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 Japanese Patent Publication No. 2016-509942 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] When inserting a medical device into the body, a dilator may be used to expand the hole created by the transseptal puncture device. This dilator typically includes a shaft in which a lumen through which a guide wire is inserted is formed. When using this dilator, a part of the guide wire is left indwelling in the body, and the shaft is pushed into the body while being guided by the guide wire.

[0005] In atrial septal puncture, contrast agent is used to confirm tenting of the atrial septum. When administering contrast agent from the tip of the shaft with the guidewire inserted through the shaft lumen, if the clearance between the inner diameter of the lumen and the outer diameter of the guidewire is small, it becomes difficult to inject the contrast agent from the tip of the shaft. On the other hand, to ensure clearance without increasing the outer diameter of the dilator, it is conceivable to increase the inner diameter of the lumen, but in this case, the thickness of the shaft wall becomes thinner, and the shaft becomes more prone to deformation.

[0006] This invention has been made in view of these problems, and its objective is to provide a dilator that can inject contrast agent while suppressing deformation. [Means for solving the problem]

[0007] To solve the above problems, a dilator according to one aspect of the present invention comprises a shaft having a lumen through which a guide wire can be inserted, wherein the cross-sectional shape of the lumen is non-circular in at least a portion of the tip of the shaft. [Effects of the Invention]

[0008] According to the present invention, a dilator is provided that can inject contrast agent while suppressing deformation. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram showing a dilator according to an embodiment. [Figure 2] Figure 1 shows a cross-sectional view of the dilator AA. [Figure 3] Figure 1 is a cross-sectional view of the dilator BB. [Figure 4] This is a perspective view of the tip of the shaft. [Figure 5] Figure 1 is a cross-sectional view of the CC of the dilator. [Figure 6] Figures 6(a) to 6(c) are diagrams illustrating the advantages of the dilator according to this embodiment. [Modes for carrying out the invention]

[0010] Embodiments for carrying out the present invention will be described below. The same or equivalent components are denoted by the same reference numerals, and redundant explanations will be omitted. In each drawing, components are omitted, enlarged, or reduced as appropriate for the sake of explanation. The drawings should be viewed in accordance with the orientation of the reference numerals. In this specification, the side of the dilator that is inserted into the body is referred to as the "tip side," and the side that is operated is referred to as the "proximal side."

[0011] Figure 1 shows a dilator 10 according to an embodiment. The dilator 10 comprises a long, hollow shaft 12 and a hub 14 provided on the base end side of the shaft 12. In this specification, "tip portion" means a certain range including the tip of the shaft 12. For example, when the total length of the shaft 12 from the tip to the base end is L, the "tip portion" means the portion of the shaft 12 that extends from the tip towards the base end with a length of (1 / 3) × L.

[0012] In this embodiment shown in Figure 1, the shaft 12 has a base portion 16 with a constant outer diameter along the axial direction and a tip portion 18 provided on the tip side of the base portion 16. A lumen is formed inside the shaft 12. The tip portion 18 includes a tapered portion 20 whose outer diameter decreases towards the tip. In this embodiment, the tapered portion 20 includes the tip 20a of the shaft. The tapered portion 20 does not necessarily include the tip 20a of the shaft. The shaft 12 may be formed using a flexible resin material that can be bent and deformed. Examples of resin materials for forming the shaft 12 include various thermoplastic elastomers such as polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, and polybutadiene-based materials.

[0013] The hub 14 includes an insertion port 22 through which a guidewire can be inserted, and a connection port 24 to which a device such as a syringe for injecting contrast agent can be connected. The guidewire inserted through the insertion port 22 can pass through the lumen of the shaft 12 and exit from the tip 20a of the tapered portion 20. When contrast agent is injected from the connection port 24 with the guidewire inserted through the lumen of the shaft 12, the contrast agent flows towards the tip through the gap between the inner surface of the shaft 12 and the guidewire in the lumen and is released from the tip 20a.

[0014] Figure 2 is a cross-sectional view AA of the dilator 10 shown in Figure 1. Figure 2 shows a cross-section (a section perpendicular to the axial direction) of the base 16 of the shaft 12. As shown in Figure 2, a circular lumen 26 with a circular cross-sectional shape is formed in the base 16 along the central axis C. The cross-sectional shape of the outer circumferential surface 16a of the base 16 is circular, and the cross-sectional shape of the inner circumferential surface 16b of the base 16 is also circular.

[0015] The circular lumen 26 is formed to a size that allows a guide wire (not shown) to be inserted. That is, the inner diameter of the circular lumen 26 is formed to be larger than the outer diameter of the guide wire.

[0016] Figure 3 is a cross-sectional view of BB of the dilator 10 shown in Figure 1. Figure 3 shows a cross-section (a section perpendicular to the axial direction) of the tip portion 18 of the shaft 12. Figure 4 is a perspective view of the tip portion 18 of the shaft 12. As shown in Figures 3 and 4, a non-circular lumen 28 with a non-circular cross-sectional shape is formed on the tip portion 18 along the central axis C. The non-circular lumen 28 of the tip portion 18 communicates with the circular lumen 26 of the base portion 16. In this embodiment shown in Figures 3 and 4, the cross-section of the non-circular lumen 28 has a petal shape, but it is not limited to a petal shape as long as it is non-circular; it may be elliptical or polygonal. The inner circumferential surface 18b of the tip portion 18 is non-circular, while the outer circumferential surface 18a of the tip portion 18 is circular.

[0017] The distal end portion 18 of the shaft 12 in which the non-circular lumen 28 is formed has a thinned portion 30 with the smallest wall thickness from the outer peripheral surface 18a to the inner peripheral surface 18b, and a thickened portion 32 with the largest wall thickness. The thinned portion 30 is a portion where the minimum distance from the central axis C to the inner peripheral surface 18b is Rmin, and the thickened portion 32 is a portion where the maximum distance from the central axis C to the inner peripheral surface 18b is Rmax. At the distal end portion 18 of the shaft 12, the thinned portions 30 and the thickened portions 32 are formed alternately in the circumferential direction. The "circumferential direction" refers to the circumferential direction of a circle centered on the central axis C. The ratio of the thickness of the thinned portion 30 to the thickened portion 32 may be 0.1 to 0.5. It is sufficient that at least a part of the distal end portion 18 of the shaft 12 satisfies this ratio. Further, in order to ensure the rigidity of the distal end portion 18 of the shaft 12, the wall thickness of the distal end portion 18 of the shaft 12 is preferably set to 0.05 mm or more.

[0018] The non-circular lumen 28 is formed to a size that allows a guide wire (not shown) to be inserted therethrough. That is, the non-circular lumen 28 is formed such that twice the minimum distance Rmin is larger than the outer diameter of the guide wire.

[0019] It is sufficient that the non-circular lumen 28 is formed in at least a part of the distal end portion 18 of the shaft 12, and the non-circular lumen 28 may be formed only in the tapered portion 20 of the distal end portion 18.

[0020] FIG. 5 is a C-C cross-sectional view of the dilator 10 shown in FIG. 1. FIG. 5 shows a longitudinal cross section (a cross section along the axial direction) of the distal end portion 18 of the shaft 12. As described above, the distal end portion 18 includes the tapered portion 20 whose outer diameter decreases toward the distal end side. In this tapered portion 20, the non-circular lumen 28 is also formed to be tapered. In the tapered portion 20, the cross-sectional area of the non-circular lumen 28 may gradually decrease toward the distal end side. Alternatively, in the tapered portion 20, the cross-sectional area of the non-circular lumen 28 may decrease stepwise toward the distal end side.

[0021] It is sufficient that the non-circular lumen 28 is formed to taper at at least a part of the distal end portion 18 of the shaft 12, and the non-circular lumen 28 may be formed to taper only at the tapered portion 20.

[0022] FIGS. 6(a) to 6(c) are diagrams for explaining the advantages of the dilator 10 according to the present embodiment. FIG. 6(a) shows a state in which a guide wire 40 is inserted through the non-circular lumen 28 of the dilator 10 according to the present embodiment. FIG. 6(b) shows a state in which the guide wire 40 is inserted through the circular lumen 50 of the dilator according to the first comparative example. FIG. 6(c) shows a state in which the guide wire 40 is inserted through the circular lumen 52 of the dilator according to the second comparative example. All of FIGS. 6(a) to 6(c) show the opening at the distal end of the shaft. The dilators shown in FIGS. 6(a) to 6(c) all have the same outer diameter of the shaft and the same outer diameter of the guide wire 40.

[0023] The circular lumen 50 of the dilator according to the first comparative example shown in FIG. 6(b) has a radius R1. The radius R1 of the circular lumen 50 is set to be the same as the maximum distance Rmax in the non-circular lumen 28 of the dilator 10 according to the present embodiment. In this first comparative example, since the gap 51 between the guide wire 40 and the inner peripheral surface of the shaft can be made large, the contrast medium can flow smoothly through this gap 51. However, in this first comparative example, since the inner diameter of the circular lumen 50 is increased, the wall thickness at the distal end of the shaft is reduced over the entire circumference (that is, the maximum value of the wall thickness at the distal end of the shaft is reduced), which may cause the shaft to be easily deformed.

[0024] The circular lumen 52 of the dilator in the second comparative example shown in Figure 6(c) has a radius R2. The radius R2 of the circular lumen 52 is the same as the minimum distance Rmin in the non-circular lumen 28 of the dilator 10 according to this embodiment. In this second comparative example, the inner diameter of the circular lumen 52 is reduced, which increases the wall thickness of the shaft compared to the first comparative example, thus suppressing shaft deformation. However, in the second comparative example, the gap 53 between the guide wire 40 and the inner surface of the shaft cannot be made large, so there is a risk that the contrast agent cannot flow smoothly through this gap 53.

[0025] In the dilator 10 according to this embodiment shown in Figure 6(a), a non-circular lumen 28 is formed at the tip 18 of the shaft 12, thereby creating alternating portions circumferentially within the non-circular lumen 28: portions 41 with a large gap between the guide wire 40 and the inner circumferential surface 18b of the tip 18, and portions 42 with a small gap between the guide wire 40 and the inner circumferential surface 18b of the tip 18. According to the dilator 10 according to this embodiment, the contrast agent can flow more smoothly through these portions with a large gap 41 compared to the second comparative example shown in Figure 6(b). Furthermore, according to the dilator 10 according to this embodiment, a thickened portion 32 is provided at the tip 18 of the shaft 12, so deformation of the tip 18 of the shaft 12 can be suppressed compared to the first comparative example shown in Figure 6(a). Thus, according to the dilator 10 according to this embodiment, by providing a non-circular lumen 28 at the tip 18 of the shaft 12, it is possible to inject the contrast agent while suppressing deformation of the tip 18 of the shaft 12.

[0026] The embodiments and variations described above are illustrative. The abstract technical ideas derived from them should not be interpreted restrictively to the content of the embodiments and variations. Many design changes, such as changes, additions, and deletions of components, are possible in the embodiments and variations. In the embodiments described above, the content that allows for such design changes is emphasized with the notation "embodiment." However, design changes are also permitted in content without such notation. The hatching applied to the cross-sections in the drawings does not limit the material to which the hatching is applied. The structures and numerical values ​​mentioned in the embodiments and variations naturally include those that can be considered identical when considering manufacturing tolerances, etc. [Explanation of Symbols]

[0027] 10 Dilator, 12 Shaft, 14 Hub, 16 Base, 18 Tip, 20 Tapered section, 22 Insertion port, 24 Connection port, 26 Circular lumen, 28 Non-circular lumen, 30 Thin section, 32 Thick section, 40 Guide wire.

Claims

1. It has a shaft with a lumen through which a guide wire can be inserted, A dilator in which the cross-sectional shape of the lumen is non-circular in at least a portion of the tip of the shaft.

2. The dilator according to claim 1, wherein thin-walled portions and thick-walled portions are alternately formed in the circumferential direction in at least a portion of the tip of the shaft.

3. The dilator according to claim 2, wherein the ratio of the thickness of the thin portion to the thickness of the thick portion is 0.1 to 0.

5.

4. The dilator according to any one of claims 1 to 3, wherein the tip of the shaft includes a tapered portion whose outer diameter decreases towards the tip.

5. The dilator according to claim 4, wherein only the tapered portion includes a portion in which the cross-sectional shape of the lumen is non-circular.

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