JP4993353B2 - Tip deflectable catheter - Google Patents

Description

  The present invention relates to a catheter capable of tip deflection operation. More specifically, the distal end of a catheter inserted into a body cavity is operated by operating an operation portion on the proximal end side disposed outside the body. The present invention relates to a catheter capable of tip deflection operation that can easily change the direction of the distal end.

  For example, in the case of an electrode catheter inserted into the heart through arterial blood vessels, the orientation of the distal end (tip) of the catheter inserted into the heart is set to the proximal end (rear end or proximal side) of the catheter placed outside the body. ) Needs to be operated to change (deflection).

  Conventionally, the following mechanism is known as a mechanism for deflecting the distal end of the catheter by operating on the proximal side.

  As the first mechanism, for example, as shown in Patent Document 1 below, a flexible support plate or support wire and a tension wire are mounted inside the distal end of a flexible catheter. It has been known. In this mechanism, it is possible to bend the support plate or the support wire connected to the tip of the tension wire by operating the tension wire on the hand side. As a result, the distal end of the catheter can be turned in a predetermined direction.

  As a second mechanism, a metal plate or the like is punched into a duckbill-shaped ring, and the ring is connected in the axial direction with a wire or the like to constitute a distal end portion of the catheter.

  Further, as a third mechanism, a shape memory alloy is charged in the tube constituting the distal end portion of the catheter, and the shape memory alloy is deformed to change the orientation of the distal end portion of the catheter. Are known.

  However, in the first mechanism described above, the lumen inside the catheter is occupied by a bending operation mechanism such as a support plate or a support wire, the lumen cross-sectional area is narrowed, and another functional member is arranged inside the lumen. It has the problem of becoming difficult. Examples of other functional members include wiring for a plurality of electrodes, cooling means, and an optical fiber.

  Since the catheter is used by being pushed through a narrow blood vessel, it is necessary to make the outer diameter of the catheter as small as possible. However, in the first mechanism, it is difficult to reduce the outer diameter of the catheter.

  In the first mechanism, when the catheter is passed through the blood vessel in a bent state through a sheath or the like and the catheter is rotated around the axis, the rotational operation force may be transmitted to the support plate having a spring force. . In such a case, there is a possibility that the distal end of the catheter is suddenly displaced by a restoring force due to twisting of the support plate. In a catheter inserted into a blood vessel, it is preferable to avoid an operation that causes sudden displacement.

  Further, the second mechanism described above requires a step of punching a metal plate or the like to form a plurality of duckbill-like rings and connecting them with a wire or the like, which is complicated in processing and increases the manufacturing cost of the catheter. It has a problem. Further, in this second mechanism, since a plurality of rings are arranged in the axial direction and the rings are connected to the rings through the wires, when the wires are cut for some reason, the plurality of rings May fall apart. For this reason, it is inferior to the reliability as a medical catheter.

Furthermore, in the third mechanism described above, a heating mechanism is required inside the catheter in order to change the shape of the shape memory alloy, the internal structure of the catheter becomes complicated, and the lumen of the catheter cannot be used effectively. There is. In addition, deformation of a shape memory alloy is difficult to control the deformation speed and the degree of deformation, and a time delay occurs due to the shape change, and there is a problem in the followability of the shape operation.
Japanese Patent No. 3232308

  The present invention has been made in view of such a situation, and an object thereof is to make effective use of the internal lumen of the catheter, and even when it is bent and rotated about the axis, a sudden displacement occurs. There is no tip deflection maneuverable catheter.

In order to achieve the above object, a catheter capable of tip deflection operation according to the present invention is provided.
A catheter tube having at least one lumen extending along an axial direction;
A single coil spring housed inside the lumen and having a flat cross-sectional shape ,
The distal end of the operation wire is connected to the flat-shaped short diameter side .
In the present invention, “the cross section is a flat shape” is not limited to “the cross section is an elliptical shape”, but includes “a rectangular shape having a flat cross section” or other “a shape having a flat cross section”. is there. In the present invention, in the “shape having a flat cross section”, the short diameter means the shortest diameter (width) of the flat cross section, and the long diameter means the longest diameter (width) of the flat cross section. ).

  In the distal deflection operable catheter according to the present invention, the coil spring having a flat cross section forms a deflection mechanism, and the distal end of the coil spring can be bent in the flat minor axis direction. Further, the inside of the coil spring is hollow, and the inside can be used as an insertion hole for an operation wire or a passage for wiring. Therefore, the internal lumen of the catheter is not blocked by the deflection mechanism, and the lumen can be used effectively.

  Further, in the distal deflection operable catheter according to the present invention, the coil spring exhibits the effect of reinforcing the catheter tube and improves the push-in characteristic of the catheter. Further, in the catheter capable of deflecting the distal end according to the present invention, since the leaf spring is not arranged inside the catheter tube, even if it is rotated around the axis in a bent state, the distal end of the catheter is suddenly moved. No significant displacement. That is, the coil spring gradually absorbs the rotational operation force and does not cause a sudden displacement at the distal end of the catheter.

  Furthermore, in the catheter capable of deflecting the distal end according to the present invention, since the deflection mechanism is constituted by a flat coil spring, the number of parts is reduced and its manufacture is easy.

  Preferably, the distal end of the operation wire is connected to the distal end side of the coil spring which is located on the flat minor axis side of the coil spring. By pulling the operation wire on the proximal end side of the catheter, the distal end of the coil spring bends to the short diameter side of the flat shape. One operation wire may be provided on each of the flat-shaped short diameter sides of the coil spring, or only one of them may be provided.

  Alternatively, the distal end of the operation wire is connected to the distal end side of the catheter tube located on the short diameter side of the flat shape of the coil spring. Also in this case, by pulling the operation wire on the proximal end side of the catheter, the distal end of the coil spring bends to the flat minor axis side. One operation wire may be provided on each of the flat-shaped short diameter sides of the coil spring, or only one of them may be provided.

  Alternatively, a distal end tip is attached to the distal end of the catheter tube, and the distal end of the operation wire is connected to the distal end tip located on the flat short side of the coil spring. Also in this case, by pulling the operation wire on the proximal end side of the catheter, the distal end of the coil spring bends to the flat minor axis side. One operation wire may be provided on each of the flat-shaped short diameter sides of the coil spring, or only one of them may be provided.

Alternatively, the catheter tube is formed with a plurality of lumens, and the coil spring is housed inside the lumen located at the approximate center of the cross section of the plurality of lumens,
An operation wire is inserted into the lumen located on the short diameter side of the flat shape of the coil spring, and the distal end of the operation wire is prevented from being detached from the distal end of the catheter tube. It is joined to the locking piece.

  Also in this case, by pulling the operation wire on the proximal end side of the catheter, the distal end of the coil spring bends to the flat minor axis side. One operation wire may be provided for each of the pair of lumens positioned on the flat minor axis side of the coil spring, or only one of the lumens may be provided.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic side view of an electrode catheter according to an embodiment of the present invention.
2 is a cross-sectional view of an essential part of the distal end side of the catheter shown in FIG.
FIG. 3 is a perspective view of a main part of the flat coil spring shown in FIG.
4 is a sectional view taken along line IV-IV shown in FIG.
FIG. 5 is a schematic view of the electrode catheter shown in FIG. 1 inserted into the sheath;
FIG. 6 is a perspective view of a main part of a catheter tube used for an electrode catheter according to another embodiment of the present invention,
7 is a cross-sectional view taken along the line VII-VII shown in FIG.

  As shown in FIG. 1, an electrode catheter 2 as a catheter capable of tip deflection operation according to an embodiment of the present invention is used, for example, for diagnosis or treatment of arrhythmia in the heart, and a distal end portion of a catheter tube 4. A tip electrode 10 and a plurality of ring electrodes 12 are attached to 4a. A connector 6 is attached to the proximal end 4 b of the catheter tube 4. From the connector 6, lead wires for conducting wires electrically connected to the electrodes 10 and 12 are drawn out. The connector 6 is equipped with a knob 7 for performing a deflection movement operation of the distal end portion of the catheter tube 4.

  The tip electrode 10 and the ring electrode 12 shown in FIG. 1 are made of a metal having good thermal conductivity, such as aluminum, copper, stainless steel, gold, or platinum. In addition, in order to give favorable contrast properties for X-rays, the tip electrode 10 and the ring electrode 12 are preferably made of platinum or the like. The outer diameters of the distal tip electrode 10 and the ring-shaped electrode 12 are not particularly limited, but are preferably about the same as the outer diameter of the catheter tube 4 and are usually about 0.5 to 3 mm. These electrodes 10 and 12 are used for measuring the potential of a living tissue such as the heart or used for ablation of living tissue.

  The catheter tube 4 is made of a synthetic resin such as polyolefin, polyamide, polyether polyamide, or polyurethane. The outer diameter of the catheter tube 4 is generally about 0.5 to 3 mm, and the inner diameter is about 0.2 to 2.5 mm. As shown in FIG. 2, the catheter tube 4 is formed with a single lumen 14 along the axial direction.

  As shown in FIGS. 3 and 4, a coil spring 20 having a flat cross section is attached to the lumen 14 of the catheter tube 4. In the embodiment shown in FIG. 4, the cross section of the coil spring 20 is elliptical, and the flatness ratio L1 / L2 of the short diameter L1 with respect to the long diameter L2 is preferably 1/2 to 1/4. The cross-sectional flat shape of the coil spring 20 is not limited to an ellipse, but may be other flat shapes.

  The major axis L2 of the coil spring 20 is a dimension equal to or smaller than the inner diameter of the catheter tube 4 shown in FIG. The cross-sectional shape of the wire 22 constituting the coil spring 20 may be circular or rectangular, or other cross-sectional shapes. When the cross section of the wire 22 constituting the coil spring 20 is circular, the outer diameter is preferably about 50 to 300 μm. Further, when the cross section of the wire 22 constituting the coil spring 20 is rectangular or other shapes, the diagonal length and the representative length in the cross section are approximately the same as the outer diameter in the case of the circular cross section. Preferably there is.

  The coil spring 20 has a wire 22 wound in an elliptical coil shape. The material of the wire 22 is not particularly limited as long as it is a material having spring characteristics. Specifically, the wire 22 is made of SUS, Ni—Ti, Fe, or the like.

  As shown in FIG. 2, the distal end 20 a of the coil spring 20 extends close to the distal tip electrode 10 connected and fixed to the distal end of the catheter tube 4, and is not in contact with the electrode 10. Although it is preferable, it may be connected and fixed as long as insulation is ensured. The proximal end (not shown) of the coil spring 20 having a flat cross section is preferably located at a distance L3 from the distal end of the catheter 2 as shown in FIG. The distance L3 is preferably about 5 to 15% of the total length L0 of the catheter 2 excluding the connector 6. The total length L0 of the catheter 2 is not particularly limited, but is preferably 300 to 1200 mm.

  At a position at a distance L3 from the distal end of the catheter 2, the proximal end of the coil spring 20 having a flat cross section is connected and fixed to the distal end of a coil spring (not shown) having a circular cross section, for example. Is preferred. The proximal end side coil spring has a reinforcing function on the proximal end side of the catheter tube 4.

  Further, as will be described later, by operating the knob 7, the distal end of the catheter tube 4 bends in the direction of the arrow A1 and the direction of the arrow A2 from the position of the distance L3 from the distal end of the catheter 2. Become. Therefore, the proximal end side coil spring may be made of a material or a structure that has higher bending elasticity than the coil spring 20 having a flat cross section disposed at the distal end thereof and is relatively difficult to bend.

  As shown in FIG. 2, near the distal end 20a of the coil spring 20 having a flat cross section, the distal ends of a pair of operation wires 30 are provided with means such as laser welding, spot welding, welding, brazing, and caulking. Are joined together. As shown in FIG. 4, the distal ends of the pair of operation wires 30 are respectively joined to the minor axis L1 side in the flat cross section of the coil spring 20.

  The outer diameter of the operation wire 30 is not particularly limited, but is preferably 0.01 to 0.2 mm, and more preferably 0.03 to 0.08 mm. The operation wire 30 is made of, for example, a Ni—Ti superelastic alloy. The operation wire 30 is inserted into the operation tube so as to be movable in the axial direction. The operation tube is made of, for example, a low-friction coefficient fluororesin (eg, PTFE) tube, and its inner diameter is slightly larger than the outer diameter of the operation wire 30, and its thickness is not particularly limited. 0.03 to 0.08 mm.

  As shown in FIG. 2, the pair of operation wires 30 passes through the inside of the flat coil spring 20 and has a circular cross-section proximal end to which the proximal end of the flat coil spring 20 is connected. It passes through the inside of the side coil spring and further extends to the operation connector 6 shown in FIG.

  The proximal end portions of the pair of operation wires 30 are driven to rotate by, for example, the rotary knob 7 of the operation connector 6 shown in FIG. 1, and one operation wire 30 is pulled, and the other operation wire 30 is pulled. It is unwound in the same amount as the amount.

  For example, as a result of operating the rotary knob 7 shown in FIG. 1, when the upper wire 30 is pulled and the lower wire 30 is unwound in FIGS. 2 to 4, the distal end 20 a of the coil spring 20 is It is deflected in the upward direction A1 along the short diameter direction L1, not the long diameter L2. This is because the coil spring 20 has low bending rigidity along the minor axis direction L1 rather than the major axis L2 direction. As a result, as shown in FIG. 1, the distal end of the catheter 2 is deflected in the upward direction A1 along the minor axis direction L1 from the position of the distance L3.

  2 to 4, if the lower wire 30 is pulled and the upper wire 30 is unwound, the distal end 20a of the coil spring 20 is not in the major axis L2 direction but in the minor axis direction L1. Is deflected in the downward direction A2. As a result, as shown in FIG. 1, the distal end of the catheter 2 is deflected in the downward direction A2 from the position of the distance L3.

  Therefore, the distal end of the catheter 2 can be deflected and bent in any A1 or A2 direction by operating the rotary knob of the connector 6 shown in FIG. If the connector 6 is rotated about the axis, the direction of the bending direction A1 or A2 with respect to the catheter tube 4 can be freely set while being inserted into the body cavity.

  In the electrode catheter 2 according to the present embodiment, the coil spring 20 having a flat cross section forms a deflection mechanism, and the distal end 20a of the coil spring 20 can be displaced in the direction of the short axis L1 of the flat shape. . Further, the inside of the coil spring 20 is hollow, and the inside thereof can be used as an insertion hole for the operation wire 30 or a path for wiring from the electrodes 10 and 12. Therefore, the internal lumen of the catheter 2 is not blocked by the deflection mechanism, and the lumen can be used effectively.

  Further, in this electrode catheter 2, the coil spring 20 exerts a reinforcing effect on the distal end side of the catheter tube 4, and improves the pushing characteristics of the catheter 2. Furthermore, in this catheter 2, since a leaf spring is not arranged inside the catheter tube 4, it is arranged in a sheath 35 and rotated around the axis in a bent state, for example, as shown in FIG. However, a sudden displacement does not occur at the distal end of the catheter 2. That is, the coil spring 20 gradually absorbs the rotational operation force and does not cause a sudden displacement at the distal end portion of the catheter 2.

  Further, in this catheter, since the deflection mechanism is constituted by the flat coil spring 20, the number of parts is reduced and its manufacture is easy.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
For example, as shown in FIG. 2, the distal ends of the pair of operation wires 30 a may be bonded to the tip electrode 10 without being bonded to the distal end 20 a of the coil spring 20. However, the joining positions of the distal ends of the pair of operation wires 30a are positioned so as to face the minor axis L1 side of the flat cross-sectional shape of the coil spring 20.

  Alternatively, the distal ends of the pair of operation wires 30 a may be joined so as to be embedded in the distal end portion 4 a of the catheter tube 4. However, the joining positions of the distal ends of the pair of operation wires 30a are positioned so as to face the minor axis L1 side of the flat cross-sectional shape of the coil spring 20.

  In the above-described embodiment, the catheter tube 4 does not have to be a single-layer resin tube, and may be a multilayer resin tube. Furthermore, the inner and outer peripheral surfaces of the metal coil spring are covered with resin. Things can be used.

  Furthermore, in the present invention, as shown in FIGS. 6 and 7, a multi-lumen type catheter tube 40 having a plurality of lumens 42 to 50 may be used. In the embodiment shown in FIG. 6 and FIG. 7, the coil spring 20 having a flat cross section is accommodated inside the lumen 42 located at the approximate center of the cross section of the plurality of lumens 42 to 50. An operation wire 30 is inserted into each of the two lumens 44 and 46 located on the flat minor axis L1 side of the coil spring 20. The distal end of each operation wire 30 is joined to a locking piece 60 that is secured to the distal end 40 a of the catheter tube 40. The other lumens 48 and 50 may be routed through wiring from the electrodes 10 and 12 shown in FIG.

  Also in this embodiment, by pulling the operation wire 30 on the proximal end side of the catheter tube 40, the distal end of the coil spring 20 is not bent toward the long diameter L2 side of the flat cross section, and the short diameter The side end L1 is bent, and the distal end 40a of the catheter tube 40 is also bent to the short diameter side L1. Other structures and operational effects of the embodiment shown in FIGS. 6 and 7 are the same as those of the embodiment shown in FIGS.

  Furthermore, the tip deflection operable catheter according to the present invention is not limited to the electrode catheter 2, and can be applied to catheters for other purposes.

FIG. 1 is a schematic side view of an electrode catheter according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the main part on the distal end side of the catheter shown in FIG. 3 is a perspective view of an essential part of the flat coil spring shown in FIG. 4 is a cross-sectional view taken along line IV-IV shown in FIG. FIG. 5 is a schematic view of the electrode catheter shown in FIG. 1 inserted into the sheath. FIG. 6 is a perspective view of a main part of a catheter tube used in an electrode catheter according to another embodiment of the present invention. 7 is a cross-sectional view taken along the line VII-VII shown in FIG.

Explanation of symbols

2 ... Electrode catheter 4, 40 ... Catheter tube 6 ... Connector 7 ... Knob 10, 12 ... Electrode 14, 42, 44, 46, 48, 50 ... Lumen 20 ... Coil spring 22 ... Wire 30 ... Operation wire 60 ... Locking Fragment

Claims (5)

A catheter tube having at least one lumen extending along an axial direction;
A single coil spring housed inside the lumen and having a flat cross-sectional shape ,
A tip deflection operable catheter in which a distal end of an operation wire is connected to the flat-shaped short diameter side .   The catheter according to claim 1, wherein a distal end of an operation wire is connected to a distal end side of the coil spring that is located on a flat minor axis side of the coil spring.   The distal deflection operable catheter according to claim 1, wherein a distal end of an operation wire is connected to a distal end side of the catheter tube located on a flat minor axis side of the coil spring. A distal tip is attached to the distal end of the catheter tube,
2. The tip deflectable manipulatable catheter according to claim 1, wherein a distal end of an operation wire is connected to the tip of the coil spring that is positioned on a flat minor axis side. In the catheter tube, a plurality of lumens are formed, and the coil spring is housed inside a lumen located at the approximate center of the cross section of the plurality of lumens,
An operation wire is inserted into the lumen located on the short diameter side of the flat shape of the coil spring, and the distal end of the operation wire is prevented from being detached from the distal end of the catheter tube. The tip-deflable manipulatable catheter according to claim 1, wherein the catheter is joined to a locking piece.

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