JP2022123938A - balloon catheter - Google Patents

Abstract

To provide a balloon catheter capable of easily adjusting a balloon to obtain a plurality of mutually different expansion diameters.SOLUTION: A balloon catheter 1A includes: a balloon 3 that can be expanded and contracted between an expanded state and a contracted state; and a diameter control member 6 for controlling an expansion diameter of the balloon 3 having a plurality of control elements 6C fixed to different positions of the balloon 3 in a circumferential direction, in which the plurality of control elements 6C are switched between a separated state in which they are separated from each other in a circumferential direction and a close state in which a distance between at least two control elements 6C of one set or more is shorter than in the separated state according to a change in external force applied between at least two control elements 6C, the balloon 3 being brought into a maximum diameter state, in which the expansion diameter is the maximum, in the separated state, and the balloon 3 being brought into an intermediate diameter state, in which the expansion diameter is an intermediate diameter smaller than the maximum diameter, in the close state.SELECTED DRAWING: Figure 3

Description

The present invention relates to balloon catheters.

The dilation capability of dilating a stenosed part in a blood vessel with a balloon catheter depends on the diameter of the balloon in its dilated state (hereinafter referred to as "expanded diameter"). Therefore, it is required to select and use a balloon catheter including a balloon with an expansion diameter suitable for the type and size of the stenosis in the blood vessel. However, in many cases, the inner diameter of the stenotic part is not constant over the longitudinal direction, and there are many cases where multiple stenotic parts with different inner diameters exist at the same time. The appropriate dilated diameter of the is not constant. In this case, even if one treatment is performed, it is necessary to use a plurality of balloon catheters each having a different expansion diameter. In this case, the longer treatment time may increase the burden on the patient, the medical staff, the operator, and the like.

US Pat. No. 5,300,009 discloses an angioplasty balloon having a selectively deployable cutting or scoring element (hereinafter simply "element"). In an angioplasty balloon, the element is helically wrapped around the balloon. In an angioplasty balloon, the balloon can be switched between fully inflated and partially inflated states by adjusting the degree of tension on a tension member connected to the element. This allows the expanded diameter of the balloon to be varied during the procedure, thus avoiding the use of multiple balloon catheters.

Japanese Patent Publication No. 2016-520369

However, with the angioplasty balloon described above, the degree of tension of the tension member must be adjusted so that the balloon has the proper expanded diameter. For this reason, there is a problem that even a user skilled in the operation often finds it difficult to operate the balloon to a desired expanded diameter.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a balloon catheter in which the balloon can be easily adjusted to a plurality of different expansion diameters.

A balloon catheter according to the present invention includes a balloon that can be expanded and contracted between an expanded state and a contracted state, and a diameter control member for controlling an expanded diameter, which is the diameter of the balloon in the expanded state, and a plurality of control elements fixed at different positions on the balloon, each of the plurality of control elements being separated from each other in the circumferential direction, and a distance between one or more sets of at least two control elements An approaching state smaller than the spaced state is switched in response to a change in an external force acting between the at least two control elements, and in the spaced state the balloon is expanded to a maximum diameter at which the expanded diameter is the maximum diameter. and the diameter control member that brings the balloon into an intermediate diameter state in which the expanded diameter is an intermediate diameter smaller than the maximum diameter in the approaching state.

The balloon catheter controls the expansion diameter of the balloon with a diameter control member. The diameter control member makes the expansion diameter of the balloon the maximum diameter when the plurality of control elements are in the separated state, and makes the expansion diameter of the balloon the intermediate diameter when the plurality of control elements are in the close state. Here, the diameter control member switches the plurality of control elements between a separated state and an approached state according to the external force acting on each. Thus, the user can switch the expanded diameter of the balloon by adjusting the external forces acting on the multiple control elements. Thus, the user can easily adjust the balloon for different expansion diameters.

In the present invention, the plurality of control elements may include four or more control elements, and the distance between two or more sets of two control elements may be smaller in the close state than in the separated state. In this case, since the balloon catheter can stabilize the approaching state of the plurality of control elements, the balloon can be stably maintained at the intermediate diameter state.

In the present invention, the plurality of control elements may be arranged at equal intervals in the circumferential direction in the separated state. In this case, in the balloon catheter, the cross-sectional shape of the balloon in the intermediate diameter state can be approximated to a circular shape, so that the narrowed portion can be uniformly expanded in the circumferential direction of the balloon.

In the present invention, said at least two control elements may contact each other in said approaching state. In this case, since the balloon catheter can appropriately exert an attractive force between the plurality of control elements, the plurality of control elements can be reliably switched between the distant state and the close state, and the expansion diameter of the balloon can be appropriately adjusted. .

In the present invention, the external force may be expansion force of the balloon, and the diameter control member may control the expansion diameter of the balloon by frictional force. In this case, the balloon catheter can stably maintain multiple control elements in approximation.

In the present invention, the at least two control elements may include at least a first control element including a recess and a second control element having a protrusion that can fit into the recess. In this case, the balloon catheter can effectively exert frictional forces between the at least two control elements.

In the present invention, the external force may be an external magnetic field, and the diameter control member may control the expanded diameter of the balloon by magnetic force. In this case, the balloon catheter can utilize magnetic forces to switch the control elements between a distant state and an approximated state.

In the present invention, the plurality of control elements may be made of magnetic material. In this case, in the balloon catheter, the diameter control member capable of switching the plurality of control elements between the separated state and the approached state using magnetic force can be realized with a magnetic material.

In the present invention, the external force may be energization of the plurality of control elements, and the diameter control member may control the expanded diameter of the balloon by electrostatic force. In this case, the balloon catheter can utilize electrostatic forces to switch the control elements between a distant state and an approximated state.

In the present invention, the plurality of control elements may be made of conductors or charged bodies. In this case, in the balloon catheter, the diameter control member capable of switching the plurality of control elements between the distant state and the close state using electrostatic force can be realized by a conductor or a charged body.

In the present invention, the plurality of control elements have a columnar shape partly notched by a plane extending parallel to the axis, and correspond to the plane from the axis in a cross section orthogonal to the axis. The angle between the two straight lines extending toward the ends of the string may be within the range of 90° to 180°. In this case, the balloon catheter can exert a strong attractive force between the two control elements. Accordingly, the balloon catheter can stably maintain multiple control elements in approximation.

In the present invention, a drug may be applied to at least part of the balloon. A balloon catheter can treat a narrowed area by applying a drug applied to the balloon to the narrowed area.

In the present invention, the balloon has a first exposed portion that is exposed in the intermediate diameter state and a second exposed portion that is not exposed in the intermediate diameter state and is exposed in the maximum diameter state. Different agents may be applied to one exposed portion and the second exposed portion. By switching the balloon between an intermediate diameter state and a maximum diameter state, the balloon catheter can apply different drugs to the stenosis.

In the present invention, the plurality of control elements may be stiffer than the balloon. Balloon catheters can perform, for example, the function of incising a stenosis with a plurality of control elements.

In the present invention, the plurality of control elements may be harder than the balloon, and the plurality of control elements may be coated with the same drug as the drug applied to the balloon. A balloon catheter, for example, when a stenosis is incised by a plurality of control elements, allows the same drug applied to the balloon to act on the incision site.

In the present invention, the plurality of control elements may be harder than the balloon, and a drug different from the drug applied to the balloon may be applied to the plurality of control elements. A balloon catheter, for example, when a stenosis is incised by a plurality of control elements, can act on the incised location with a drug different from the drug applied to the balloon.

Fig. 10 shows the balloon catheter 1A when the balloon 3 is in a contracted state; Fig. 10 shows the balloon catheter 1A when the balloon 3 is in an intermediate diameter state; FIG. 10 is a diagram showing the balloon catheter 1A when the balloon 3 is in the maximum diameter state; FIG. 3 is a diagram for explaining a mode of use of the balloon catheter 1A; FIG. 3 is a diagram for explaining a mode of use of the balloon catheter 1A; FIG. 10 is a diagram for explaining a balloon catheter 1A in a first modified example; FIG. 11 is a diagram for explaining a plurality of control elements 6D in a second modified example and a plurality of control elements 6E and 6F in a third modified example; FIG. 11 is a diagram for explaining balloon catheters 1B and 1C in a fourth modified example;

<Overview of balloon catheter 1A>
One embodiment of a balloon catheter 1A according to the present invention will be described with reference to the drawings. The drawings to be referred to are used to explain the technical features that can be employed by the present invention, and the configuration and the like of the devices described are not meant to be limited to them, but merely illustrative examples.

The balloon catheter 1A is used to dilate stenotic lesions (hereinafter referred to as "stenotic lesions") formed in vessels such as blood vessels, vas deferens, fallopian tubes, lymph vessels, etc., and to reperfuse the vessels. used. Here, when the inner diameter of the stenotic lesion is not constant in the longitudinal direction, or when multiple stenotic lesions with different lumen diameters exist at the same time, it is necessary to dilate the stenotic lesion appropriately. There is a possibility that the diameter of time (hereinafter referred to as "expansion diameter") will not be constant.

On the other hand, the balloon catheter 1A has a catheter shaft 2, a balloon 3 and a diameter control member 6 (see FIGS. 1 to 3) which will be described later. By using the diameter control member 6, the balloon catheter 1A can be inflated to a plurality of different expansion diameters. Therefore, by controlling the balloon 3 so as to have an appropriate expansion diameter according to the stenotic lesion, it is possible to perform surgery using the common balloon catheter 1A.

As shown in FIGS. 1-3, the balloon 3 is connected to one end of the catheter shaft 2 . A diameter control member 6 is provided on the balloon 3 . The balloon catheter 1A is used with a hub (not shown) connected to the other end of the catheter shaft 2 . The hub can supply compressed fluid to the balloon 3 through the catheter shaft 2 . One of the two ends of the catheter shaft 2 is hereinafter referred to as the "tip". The end on the other side of both ends of the catheter shaft 2 is called a "proximal end". A direction extending along the catheter shaft 2 is referred to as an "extending direction". On a plane orthogonal to the extending direction, the side closer to the cross-sectional center of the catheter shaft 2 in the radial direction with respect to the cross-sectional center of the catheter shaft 2 is called the "inner side" and is separated from the cross-sectional center of the catheter shaft 2. The side is called "outside".

<Catheter shaft 2>
The catheter shaft 2 has an outer tube 21 and an inner tube 22 . The outer tube 21 and the inner tube 22 are each flexible tubular members. The inner diameter of the outer tube 21 is larger than the outer diameter of the inner tube 22 . The inner tube 22 is arranged in the lumen of the outer tube 21 except for a predetermined portion on the distal end side. A predetermined portion on the distal end side of the inner tube 22 protrudes toward the distal end side from the distal end of the outer tube 21 (hereinafter referred to as "the distal end 211"). The distal end of the inner tube 22 (hereinafter referred to as “the distal end 221 ”) is arranged further distally than the distal end 211 of the outer tube 21 . A predetermined portion on the distal end side of the inner tube 22 is hereinafter referred to as a "protruding portion 225". Although the material of the outer tube 21 and the inner tube 22 is not particularly limited, polyamide-based resin is used as an example.

Compressed fluid supplied from the hub flows through a space of the lumen of the outer tube 21 other than the lumen of the inner tube 22 . The balloon 3 is inflated in response to the supply of compressed fluid. A guide wire (not shown) is passed through the lumen of the inner tube 22 .

<Balloon 3>
The balloon 3 can expand and contract between a deflated state (see FIG. 1) and an expanded state (see FIGS. 2 and 3). A deflated state indicates a state of the balloon 3 in which no compressed fluid is supplied. The expanded state indicates the state of the balloon 3 supplied with compressed fluid. One end of the balloon 3 in the extending direction (hereinafter referred to as “distal end 3D”) is connected to the vicinity of the distal end 221 of the projecting portion 225 of the inner tube 22 by heat welding. The end of the balloon 3 on the other side in the extending direction (hereinafter referred to as “base end 3P”) is connected to the vicinity of the distal end 211 of the outer tube 21 by heat welding. The balloon 3 covers the projecting portion 225 of the inner tube 22 from the outside. Although the material of the balloon 3 is not particularly limited, polyamide-based resin is used as an example.

As shown in FIG. 1, the balloon 3 is a three-wing type balloon in which three wings (wings 31, 32, 33) are formed in a deflated state. Each of wings 31 , 32 , 33 is folded and wrapped around protruding portion 225 of inner tube 22 . The wings 31, 32, 33 are also called "flaps" and "wings". The diameter of the balloon 3 in the contracted state is called "minimum diameter Rmin". 1, a diameter control member 6 (see FIGS. 2 and 3), which will be described later, is omitted.

As shown in FIGS. 2 and 3, the diameter of the balloon 3 in the expanded state is larger than the minimum diameter Rmin, which is the diameter of the balloon 3 in the deflated state. A distal cone region 3A, an expansion region 3B, and a proximal cone region 3C of the balloon 3 are defined below. The distal cone region 3A is a region that extends from the distal end 3D toward the proximal end 3P of the expanded balloon 3 while increasing in diameter. The proximal-side cone region 3C is a region that extends from the proximal end 3P toward the distal end 3D of the expanded balloon 3 while increasing in diameter. The expanded region 3B is a region sandwiched between the distal cone region 3A and the proximal cone region 3C in the expanded balloon 3, and has substantially the same diameter along the extending direction. A side surface of the expansion region 3B of the balloon 3 is referred to as a "side surface 30". Although the details will be described later, the expanded diameter of the balloon 3 in the expanded state is controlled in multiple stages by the diameter control member 6 described later (see FIGS. 2 and 3).

A drug is applied to the side surface 30 of the balloon 3 . Although the type of drug is not particularly limited, for example, a well-known drug that can be adhered to a stenotic lesion for treatment can be used.

<Diameter control member 6>
The diameter control member 6 shown in FIGS. 2 and 3 controls the expanded diameter of the balloon 3 in the expanded state. The diameter control member 6 has control elements 61A, 61B, 62A, 62B, 63A, and 63B (hereinafter collectively referred to as "a plurality of control elements 6C"). Each of the plurality of control elements 6C has a columnar shape and extends along the outer peripheral surface of the balloon 3 in the extension direction. A plurality of control elements 6C are arranged and fixed in the inflation region 3B of the balloon 3 . The extension direction length of each of the plurality of control elements 6C is substantially equal to the extension direction length of the inflation region 3B of the balloon 3 . Various materials described later can be used as the material of each of the plurality of control elements 6C, but at least a material harder than the balloon 3 is used. Hereinafter, the control elements 61A and 61B are also collectively referred to as "a pair of control elements 61". The control elements 62A and 62B are also collectively referred to as "a pair of control elements 62". The control elements 63A and 63B are also collectively referred to as "a pair of control elements 63". The pair of control elements 61, 62, 63 are collectively referred to as "a pair of control elements 60". Control elements 61A, 62A and 63A are collectively referred to as "control element 60A", and control elements 61B, 62B and 63B are collectively referred to as "control element 60B".

The diameter control member 6 switches between a state in which the control elements 60A and 60B are in contact with each other and a state in which the control elements 60B are separated from each other according to an external force (external magnetic field, energization of an external conductor (not shown), etc.), which will be described later. More specifically, an attractive force acts between the control elements 60A, 60B in the presence of an external force. This attraction forces the control elements 60A, 60B into contact with each other. This state is maintained even when the compressed fluid is supplied to the balloon 3 . On the other hand, when no external force acts, the attractive force between the control elements 60A, 60B is eliminated. In this case, the control elements 60A, 60B are separated from each other in response to the supply of compressed fluid to the balloon 3 .

As shown in FIG. 2, the state of the plurality of control elements 6C in which the respective control elements 60A and 60B of the pair of control elements 61, 62 and 63 are in contact with each other is called "approach state". The expansion diameter of the balloon 3 in which the plurality of control elements 6C are in an approaching state is referred to as "intermediate diameter Rmid". The expanded state of the balloon 3 in which the plurality of control elements 6C are in the closed state is referred to as the "intermediate diameter state".

In the balloon 3 in the intermediate diameter state, the tips of the wings 31 are close to part of the wings 32 on the side surface 30 . The tip of wing 32 is close to a portion of wing 33 on side surface 30 . The tip of wing 33 is close to a portion of wing 31 on side surface 30 . Control element 61A is located at the tip of wing 31 . The control element 61B is arranged on the portion of the wings 32 on the side 30 of the balloon 3 that is adjacent to the tips of the wings 31 . The control elements 61A, 61B are in contact. Control element 62A is located at the tip of wing 32 . The control element 62B is located on the portion of the wing 33 on the side 30 of the balloon 3 that is adjacent to the tip of the wing 32 . The control elements 62A, 62B are in contact. Control element 63A is located at the tip of wing 33 . The control element 63B is arranged on the part of the wings 31 on the side 30 of the balloon 3 that is adjacent to the tips of the wings 33 . The control elements 63A, 63B are in contact. Note that the locations where the control elements 61A, 62A, and 63A are arranged are not limited to the tips of the wings 31, 32, and 33, and any other location (for example, inside each of the wings 31, 32, and 33). abdomen).

A portion of the side surface 30 of the balloon 3 that is exposed even in the intermediate diameter state is referred to as a "first exposed portion 30A". A portion of the side surface 30 of the balloon 3 that is covered by the wings 31, 32, and 33 in the intermediate diameter state and is not exposed is referred to as a "second exposed portion 30B." Different chemicals are applied to the first exposed portion 30A and the second exposed portion 30B. Hereinafter, the chemical applied to the first exposed portion 30A is referred to as "first chemical". The chemical applied to the second exposed portion 30B is called "second chemical".

Of the side surface 30 of the balloon 3 in the intermediate diameter state, the portion between the control elements 61A and 63B in the circumferential direction corresponds to the first exposed portion 31A that is exposed even in the contracted state, and the portion between the control elements 61A and 61B in the circumferential direction The portion corresponds to the second exposed portion 31B which is not exposed in the contracted state. Of the side surface 30 of the balloon 3 in the intermediate diameter state, the portion between the control elements 62A, 61B in the circumferential direction corresponds to the first exposed portion 32A exposed even in the deflated state, and the portion between the control elements 62A, 62B in the circumferential direction corresponds to the first exposed portion 32A exposed even in the contracted state. corresponds to the second exposed portion 32B which is not exposed in the contracted state. Of the side surface 30 of the balloon 3 in the intermediate diameter state, the portion between the control elements 63A and 62B in the circumferential direction corresponds to the first exposed portion 33A that is exposed even in the contracted state, and the portion between the control elements 63A and 63B in the circumferential direction corresponds to the second exposed portion 33B which is not exposed in the contracted state.

On the other hand, as shown in FIG. 3, the state in which the plurality of control elements 6C are all separated from each other in the expanded balloon 3 is referred to as the "separated state." The expansion diameter of the balloon 3 in which the plurality of control elements 6C are separated is called "maximum diameter Rmax". The expanded state of the balloon 3 in which the plurality of control elements 6C are separated is referred to as the "maximum diameter state". When the balloon 3 is in the maximum diameter state, the positions where each of the plurality of control elements 6C are fixed differ in the circumferential direction of the balloon 3 . Each of the plurality of control elements 6C is circumferentially arranged at regular intervals with respect to the balloon 3 . The control elements 61A, 61B, 62A, 62B, 63A, 63B are arranged in this order in the circumferential direction. Each of the plurality of control elements 6C are spaced apart from each other in the circumferential direction. The wings 31 to 33 of the balloon 3 are eliminated when the balloon 3 reaches its maximum diameter. In this case, not only the first exposed portion 30A of the balloon 3 but also the second exposed portion 30B are exposed.

A chemical is applied to the plurality of control elements 6C. Although the type of drug is not particularly limited, for example, a well-known drug that can be adhered to a stenotic lesion for treatment can be used. Also, the drug may be the same drug as the drug applied to the side surface 30 of the balloon 3 (the first drug or the second drug), or may be a different drug.

<External force>
Although the attractive force acting between the control elements 60A and 60B is not particularly limited, magnetic force or electrostatic force is preferably used as an example.

When magnetic force is used as the attractive force, the plurality of control elements 6C are made of magnetized magnetic bodies. Although the material of the magnetic body is not particularly limited, electromagnetic stainless steel, silicon iron, neodymium magnets, etc. are preferably used. Also, an external magnetic field is used as an external force for switching the control elements 60A and 60B between the contact state and the separated state.

For example, when an external magnetic field acts on a plurality of control elements 6C, magnetic force acts as an attractive force between all control elements 60A and 60B. In this case, the magnetic force acts in a direction in which the control elements 61A and 61B, the control elements 62A and 62B, and the control elements 63A and 63B approach each other. In this case, as shown in FIG. 2, the expanded diameter of the balloon 3 is an intermediate diameter Rmid that is larger than the minimum diameter Rmin in the contracted state and smaller than the maximum diameter Rmax in the maximum diameter state.

On the other hand, the magnetic forces between all the control elements 60A and 60B are nullified when the external magnetic field does not act on the plurality of control elements 6C, for example. No magnetic force acts between the control elements 60A, 60B. When the balloon 3 is inflated by being supplied with compressed fluid, all the control elements 60A and 60B are separated from each other. As a result, as shown in FIG. 3, the expanded diameter of the balloon 3 becomes a maximum diameter Rmax larger than the minimum diameter Rmin in the contracted state and the intermediate diameter Rmid in the intermediate diameter state. Therefore, by controlling the magnitude of the external magnetic field acting on the plurality of control elements 6C, the balloon 3 in the inflated state can be switched between the intermediate diameter state and the maximum diameter state.

When electrostatic force is used as the attractive force, the plurality of control elements 6C are formed by charged conductors or electrified bodies. Although the material of the conductor or charged body is not particularly limited, copper, aluminum, silver and the like are preferably used. Also, by switching the energized state of the plurality of control elements 6C, the control elements 60A and 60B are switched between a state in which they are in contact with each other and a state in which they are separated from each other. In other words, energization of the plurality of control elements 6C is used as an external force for switching the control elements 60A and 60B between the state in which they are in contact with each other and the state in which they are separated.

For example, an electrostatic force acts as an attractive force between all the control elements 60A and 60B in a state where the plurality of control elements 6C are energized via external conductors (not shown). In this case, the control elements 61A and 61B, the control elements 62A and 62B, and the control elements 63A and 63B act in a direction in which the control elements 61A and 61B, the control elements 62A and 62B, and the control elements 63A and 63B approach each other. In this case, as shown in FIG. 2, the expanded diameter of the balloon 3 is an intermediate diameter Rmid that is larger than the minimum diameter Rmin in the contracted state and smaller than the maximum diameter Rmax in the maximum diameter state.

On the other hand, for example, when the energization of the plurality of control elements 6C is stopped, the electrostatic forces between the control elements 61A and 61B, between the control elements 62A and 62B, and between the control elements 63A and 63B are all nullified. There is no longer any electrostatic force between the control elements 60A, 60B. When the balloon 3 is inflated by being supplied with compressed fluid, all the control elements 60A and 60B are separated from each other. As a result, as shown in FIG. 3, the expanded diameter of the balloon 3 becomes a maximum diameter Rmax larger than the minimum diameter Rmin in the contracted state and the intermediate diameter Rmid in the intermediate diameter state. Therefore, it is possible to switch the balloon 3 between the intermediate diameter state and the maximum diameter state by controlling the magnitude of the electric current applied to the plurality of control elements 6C.

As described above, the plurality of control elements 6C control the expansion diameter of the balloon 3 in the expanded state by switching between the state in which the control elements 60A and 60B are in contact with each other and the state in which they are separated from each other according to external force.

<Usage example>
A usage example of the balloon catheter 1A will be described with reference to FIGS. 4 and 5. FIG. A case in which the balloon catheter 1A is used to dilate stenotic lesions 90A and 90B that have occurred on part of the inner wall of the vessel 9 is illustrated. The inner diameter of the lumen of stenosing lesion 90B is larger than the inner diameter of the lumen of stenosing lesion 90A.

A guide wire G is passed through the vessel 9 . As shown in FIG. 4A, a balloon catheter 1A is prepared with the balloon 3 in a deflated state. For example, when a magnetic material is used as the plurality of control elements 6C, the external magnetic field does not act on the plurality of control elements 6C. Further, for example, when a conductor or a charged body is used as the plurality of control elements 6C, energization to the plurality of control elements 6C is stopped. Next, a portion of the balloon catheter 1A that includes at least the balloon 3 is placed inside the vessel 9 . A guide wire G is passed through the inner tube 22 of the balloon catheter 1A.

Next, the balloon catheter 1A is pushed into the vessel 9 along the guide wire G by manipulating the proximal end of the balloon catheter 1A. As shown in FIG. 4B, the balloon catheter 1A moves distally in the vessel 9 toward the stenotic lesion 90A with the balloon 3 positioned at the head in the movement direction. When the balloon 3 reaches the stenotic lesion 90A, movement of the balloon catheter 1A is stopped.

Next, for example, when a magnetic material is used as the plurality of control elements 6C, an external magnetic field is applied to the plurality of control elements 6C. Further, for example, when a conductor or a charged body is used as the plurality of control elements 6C, current is passed through the plurality of control elements 6C through external conductors. In these cases, magnetic force or electrostatic force acts between all control elements 60A and 60B, and all control elements 60A and 60B are brought into contact with each other by magnetic force or electrostatic force. In this state, the compressed fluid is started to be supplied to the balloon 3, and the balloon 3 is in an inflated state. However, since all the control elements 60A, 60B are in contact with each other, the diameter of the balloon 3 increases from the minimum diameter Rmin in the contracted state to the intermediate diameter Rmid. As a result, the balloon 3 dilates the stenotic lesion 90A, as shown in FIG. 4(C).

The supplied compressed fluid is then removed from the balloon 3 and the balloon 3 is deflated. As a result, the diameter of the balloon 3 also decreases from the intermediate diameter Rmid to the minimum diameter Rmin (see FIG. 4(D)). Also, the application of external force is stopped and no magnetic or electrostatic force acts between all control elements 60A, 60B.

The proximal end of the balloon catheter 1A is then manipulated to move the balloon 3 distally within the vessel 9 toward the stenotic lesion 90B. As shown in FIG. 5A, movement of the balloon catheter 1A is stopped when the balloon 3 reaches the stenotic lesion 90B.

Next, the supply of compressed fluid to the balloon 3 is started. Note that unlike the case where the stenotic lesion 90A is dilated by the balloon 3 (see FIG. 4C), no external force is applied to the plurality of control elements 6C. Therefore, the state in which no magnetic force or electrostatic force acts between all the control elements 60A and 60B is maintained. The expanded diameter of the balloon 3 increases from a minimum diameter Rmin to a maximum diameter Rmax. As a result, the balloon 3 dilates the stenotic lesion 90B, as shown in FIG. 5(B).

The compressed fluid is then removed from the balloon 3 . In this case, as shown in FIG. 5(C), the balloon 3 is contracted and the diameter is reduced to the minimum diameter Rmin.

After dilation of the stenotic lesions 90A and 90B is completed, the proximal end of the balloon catheter 1A is manipulated to move the balloon catheter 1A proximally as shown in FIG. 5(D). The operation is completed by pulling out the balloon catheter 1A from the vessel 9 to the outside.

<Actions and effects of the present embodiment>
The balloon catheter 1A controls the expansion diameter of the balloon 3 with the diameter control member 6. As shown in FIG. The diameter control member 6 sets the expansion diameter of the balloon 3 to the maximum diameter Rmax when the plurality of control elements 6C are in the separated state. On the other hand, the diameter control member 6 sets the expansion diameter of the balloon 3 to the intermediate diameter Rmid when the plurality of control elements 6C are in the close state. Here, the diameter control member 6 switches the plurality of control elements 6C between the distant state and the close state in accordance with the external force acting on each. Therefore, the user can switch the expanded diameter of the balloon 3 by adjusting the external force acting on the plurality of control elements 6C. Therefore, the user can easily adjust the balloon 3 to have a plurality of different expansion diameters.

An appropriate balloon catheter is preferably selected so that the balloon can be expanded to the desired expansion diameter. However, if it is difficult to specify the desired dilation diameter, for example, if the procedure is performed using a balloon with a medium dilation diameter and the stenotic lesion is inadequately dilated, a balloon with a large dilation diameter is used. It may also occur when surgery is performed. The balloon catheter 1A is also effective for such problems. This is because a common balloon catheter 1A can be used, and the expansion diameter of the balloon 3 can be switched between a plurality of sizes.

The control elements 60A, 60B contact each other in the closed state. Therefore, the balloon catheter 1A can appropriately apply an attractive force between the control elements 60A and 60B, so that the plurality of control elements 6C can be reliably switched between the distant state and the close state, and the expansion diameter of the balloon 3 can be properly adjusted. can be adjusted to

The diameter control member 6 has a pair of control elements 61 , 62 , 63 . When the plurality of control elements 6C are in the closed state, the control elements 60A, 60B contact each other as shown in FIG. In this case, since the balloon catheter 1A can stabilize the approaching state of the plurality of control elements 6C, the balloon 3 can be stably maintained in the intermediate diameter state.

6 C of several control elements are arrange|positioned at equal intervals in the circumferential direction in a separated state (refer FIG. 3). In this case, the balloon catheter 1A can make the cross-sectional shape of the balloon 3 in the intermediate diameter state approximate to a circle. Therefore, the balloon catheter 1A can uniformly dilate the stenotic lesion in the circumferential direction of the balloon 3 .

When an external magnetic field is used as the external force, the diameter control member 6 controls the expanded diameter of the balloon 3 by magnetic force. Also, the plurality of control elements 6C are made of a magnetic material. In this case, the balloon catheter 1A can switch the plurality of control elements 6C between the separated state and the approached state using magnetic force.

When energization of a plurality of control elements 6C is used as an external force, the diameter control member 6 controls the expanded diameter of the balloon 3 by electrostatic force. Also, the plurality of control elements 6C are made of conductors or charged bodies. In this case, the balloon catheter 1A can switch the plurality of control elements 6C between the distant state and the close state using electrostatic force.

A drug is applied to the side surface 30 of the balloon 3 . In this case, the balloon catheter 1A can treat the stenotic lesion by causing the drug applied to the balloon 3 to act on the stenotic lesion. In addition, different drugs are applied to the first exposed portion 30A of the side surface 30 of the balloon 3 that is exposed in the intermediate diameter state and the second exposed portion 30B that is not exposed in the intermediate diameter state and is exposed in the maximum diameter state. . In this case, by switching the balloon 3 between the intermediate diameter state and the maximum diameter state, the balloon catheter 1A can apply different drugs to the stenotic lesion.

Since the plurality of control elements 6C are harder than the balloon 3, the balloon catheter 1A can realize, for example, the function of incising a stenotic lesion with the plurality of control elements 6C. Further, for example, when the same drug as the drug applied to the balloon 3 is applied to the plurality of control elements 6C, the balloon catheter 1A applies the same drug to the balloon 3 as the stenotic lesion incised by the plurality of control elements 6C. The same drug can act as the drug given. On the other hand, for example, when a drug different from the drug applied to the balloon 3 is applied to the plurality of control elements 6C, the balloon catheter 1A applies the balloon 3 to the stenotic lesion incised by the plurality of control elements 6C. A drug different from the drug used can act.

<First modification>
Each of the pair of control elements 61 , 62 , 63 may differ in tendency of change in attractive force when an external force acts on the control elements 60</b>A, 60</b>B. In this case, for example, by adjusting the magnitude of the external force, for each of the pair of control elements 61, 62, 63, it is possible to individually switch between the state in which the control elements 60A, 60B are in contact with each other and the state in which they are separated from each other. can.

For example, when an external force of a predetermined first strength F1 acts on the balloon 3, no magnetic or electrostatic force acts between the control elements 61A, 61B and they may be separated from each other. On the other hand, a magnetic force or an electrostatic force acts as an attractive force between the control elements 62A, 62B and between the control elements 63A, 63B, and they may come into contact with each other. In this case, as shown in FIG. 6, the control elements 61A, 61B may be spaced apart and the wings 31 (see FIG. 1) eliminated. On the other hand, the control elements 62A, 62B are kept in contact with each other and the control elements 63A, 63B are kept in contact with each other, and the wings 32, 33 may also be kept. The expanded diameter of the balloon 3 in this state is larger than the intermediate diameter Rmid (see FIG. 2) and smaller than the maximum diameter Rmax (see FIG. 3). Hereinafter, the expanded diameter of the balloon 3 in this state is referred to as "intermediate diameter Rmid(1)".

Also, for example, when an external force of a predetermined second strength F2 smaller than the first strength F1 acts on the balloon 3, not only between the control elements 61A and 61B but also between the control elements 62A and 62B. Magnetic or electrostatic forces cease to act and may separate from each other. In this case, balloon 3 may be further expanded from the state shown in FIG. 6, control elements 62A, 62B may be further spaced apart from each other and wings 32 (see FIG. 2) may be dissolved. Since the control elements 63A and 63B are maintained in contact with each other, the wing 33 is maintained. The expanded diameter of the balloon 3 in this state is larger than the intermediate diameter Rmid(1) and smaller than the maximum diameter Rmax. Hereinafter, the expanded diameter of the balloon 3 in this state is referred to as "intermediate diameter Rmid(2)".

Also, for example, if an external force of a predetermined third strength F3, less than the second strength F2, acts on the balloon 3, all control elements 60A, 60B may move away from each other. In this case, the balloon 3 is in the maximum diameter state, and the expansion diameter becomes the maximum diameter Rmax.

As described above, the balloon 3 is in the maximum diameter state (see FIG. 2) in response to the external force of the first strength F1 or the second strength F2 greater than the third strength F3. On the other hand, it is possible to make it a state in which only a part is folded. In this case, the balloon catheter 1A can switch the expanded diameter of the balloon 3 to any one of the intermediate diameters Rmid, Rmid(1), Rmid(2), and the maximum diameter Rmax.

In the above, the expanded diameter of the balloon 3 may be reversibly controlled between the intermediate diameters Rmid(0), Rmid(1), Rmid(2) and the maximum diameter Rmax. For example, the expansion diameter of the balloon 3 may be controlled in order as Rmid, Rmid(1), Rmax, Rmid(2), Rmax to expand a plurality of stenotic lesions.

<Second modification>
A second modification of the balloon catheter 1A will be described. In a second modification shown in FIG. 7A, instead of the plurality of control elements 6C in the diameter control member 6, a plurality of control elements 6D are used. The configuration other than the plurality of control elements 6C is the same as the balloon catheter 1A described in the above embodiment. As shown in FIG. 7A, the plurality of control elements 6D includes a plurality of pairs of control elements 65, and each pair of control elements 65 is composed of control elements 65A and 65B.

Each of the control elements 65A, 65B has a partially notched columnar shape and extends in the extension direction. More specifically, the control elements 65A and 65B have a shape in which a portion of the cylinder is cut away by a plane extending parallel to the axis C1 of the cylinder. A cross section of the control elements 65A, 65B taken along a plane perpendicular to the axis C1 includes an arc 651 and a chord 652 extending between the ends of the arc 651. Also, when viewed from the direction in which the axis C1 extends, the angle θ between two straight lines extending from the axis C1 toward both ends Q of the chord 652 is not particularly limited, but is preferably 90° to 180°. is within the range of

Magnetic force, for example, is preferably used as the attractive force acting between the control elements 65A and 65B. For example, a magnetic force acts as an attractive force between the control elements 65A and 65B while an external magnetic field acts on the plurality of control elements 6D. In addition, since both ends Q of the string 652 are magnetic poles, a strong magnetic force acts between the control elements 65A and 65B in a direction to bring them closer to each other. As a result, the control elements 65A, 65B contact with their respective strings 652 facing each other. On the other hand, for example, when no external magnetic field acts on the plurality of control elements 6D, the magnetic force between the control elements 65A and 65B is nullified. In this case, the control elements 65A and 65B are separated.

As described above, each pair of control elements 65 can exert a strong magnetic force between the control elements 65A and 65B. Therefore, the balloon catheter 1A can stably maintain the contact state of the control elements 65A and 65B.

<Third modification>
A third modification of the balloon catheter 1A will be described. In the third modification shown in FIGS. 7B and 7C, instead of the plurality of control elements 6C in the diameter control member 6, a plurality of control elements 6E (see FIG. 7B), 6F (see FIG. 7C) )) is used. The configuration other than the plurality of control elements 6C is the same as the balloon catheter 1A described in the above embodiment.

As shown in FIG. 7B, the plurality of control elements 6E includes a plurality of pairs of control elements 66, and each pair of control elements 66 is composed of control elements 66A and 66B. Further, as shown in FIG. 7C, the plurality of control elements 6F includes a plurality of pairs of control elements 67, and each pair of control elements 67 is composed of control elements 67A and 67B. . Frictional force is preferably used as the attractive force acting between the control elements 66A and 66B and between the control elements 67A and 67B. Furthermore, as an external force for switching the control elements 66A, 66B and the control elements 67A, 67B between the contact state and the separated state, a circumferential force acting on the side surface 30 of the balloon 3 during expansion (hereinafter referred to as (referred to as “expansion force”) is used.

As shown in FIG. 7B, the control elements 66A, 66B have a prismatic shape and extend in the extension direction. One surface Sa of the control element 66A is formed with a recess 661 recessed toward a surface Ua facing the surface Sa. The cross-sectional shape of the recess 661 is circular, and the diameter is constant regardless of the depth. One surface Sb of the control element 66B has a protrusion 662 projecting in the direction opposite to the surface Ub facing the surface Sb. The convex portion 662 has a cylindrical shape and a constant diameter regardless of its height. The protrusion 662 of the control element 66B can fit into the recess 661 of the control element 66A. With the protrusion 662 fitted in the recess 661, the control elements 66A, 66B are in contact. Also, the control elements 66A and 66B are difficult to separate due to the frictional force acting on the contact surfaces that contact each other.

As shown in FIG. 7C, the control elements 67A, 67B have a prismatic shape and extend in the extension direction. One surface Fa of the control element 67A has a plurality of recesses 671 recessed toward the surface Ea opposite to the surface Fa. Each of the plurality of recesses 671 has a circular cross-sectional shape, and the diameter decreases as the depth increases. One surface Fb of the control element 67B has a plurality of protrusions 672 projecting in the direction opposite to the surface Eb facing the surface Fb. Each of the plurality of protrusions 672 has a conical shape, and the diameter decreases as the height increases. The plurality of protrusions 672 of the control element 67B can fit into the plurality of recesses 671 of the control element 67A. The control elements 67A and 67B are in contact with each other with the plurality of protrusions 672 fitted into the plurality of recesses 671 . Also, the control elements 67A and 67B are difficult to separate due to the frictional force acting on the contact surfaces that contact each other.

A usage example of the plurality of control elements 6E and 6F will be described by taking the plurality of control elements 6E as an example. In the deflated state of the balloon 3, the protrusion 662 fits into the recess 661 and the control elements 66A, 66B are in contact with each other. In this state, the compressed fluid is started to be supplied to the balloon 3, and the balloon 3 is in an inflated state. However, the control elements 66A and 66B are in contact with each other, and are difficult to separate due to the frictional force acting on their contact surfaces. Therefore, the balloon 3 is in the intermediate diameter state, and the expanded diameter becomes the intermediate diameter Rmid (see FIG. 2).

More compressed fluid is then supplied to the balloon 3 to space the control elements 66A, 66B apart. In this case, the balloon 3 is inflated and a circumferential force (expansion force) acts on the side surface 30 . When this force of expansion becomes greater than the frictional force between the control elements 66A, 66B, the control elements 66A, 66B move apart. In this case, the balloon 3 is in the maximum diameter state, and the expansion diameter becomes the maximum diameter Rmax.

As described above, the multiple control elements 6E can stably maintain the multiple control elements 6E in the approaching state by utilizing the frictional force between the control elements 66A and 66B. Further, by fitting the concave portion 661 and the convex portion 662, frictional force can be efficiently applied between the control elements 66A and 66B.

In order for the frictional force to act efficiently between the control elements 66A and 66B, the mutual contact surfaces do not have to be smooth, and for example, slight irregularities are preferably formed.

<Fourth modification>
Balloon catheters 1B and 1C according to the fourth modification will be described with reference to FIG. Balloon catheters 1B and 1C each differ from the above embodiment in the shape of the control element.

In the balloon catheter 1B shown in FIG. 8(A), the plurality of control elements 71 have a cylindrical shape and extend in the extension direction. The length of the plurality of control elements 71 in the extension direction is shorter than the length of the expansion region 3B of the balloon 3 in the extension direction. A plurality of control elements 71 are arranged not only in the circumferential direction of the balloon 3 but also in the stretching direction. That is, the plurality of control elements 71 have a shape in which each of the plurality of control elements 6C described in the above embodiment is divided into a plurality of pieces in the extending direction. Furthermore, in the balloon catheter 1B, not only the inflation region 3B of the balloon 3 but also the distal cone region 3A and the proximal cone region 3C are provided. In the balloon catheter 1C shown in FIG. 8(B), the multiple control elements 72 have a spherical shape. A plurality of control elements 72 are randomly fixed to the sides 30 of the balloon 3 .

A balloon catheter 1B having a plurality of control elements 71 shown in FIG. 8A has better followability to the vessel 9 than the balloon catheter 1A. Further, the balloon catheter 1C having a plurality of control elements 72 shown in FIG. 8(B) has better followability to the vessel 9 than the balloon catheter 1B.

<Other Modifications>
The present invention is not limited to the above embodiments, and various modifications are possible. Although the modified example will be described below on the premise of the balloon catheter 1A, it goes without saying that it can be applied to the balloon catheters 1B, 1C and the like as appropriate.

The balloon catheter 1A may not have the outer tube 21 and the inner tube 22. In this case, the balloon catheter 1A should have at least the balloon 3 and the diameter control member 6. The total number of control elements 6C is not limited to six, and may be any number of two or more. However, in order to stabilize the intermediate diameter state, the total number of the plurality of control elements 6C is preferably 4 or more and 10 or less. Furthermore, it is most preferable that the number of control elements 6C is six. The plurality of control elements 6C are not limited to being fixed to the side surface 30 of the balloon 3, and may be fixed to the inner surface of the balloon 3 or incorporated inside the balloon 3, for example. The distal ends of the plurality of control elements 6C may be connected near the distal end 221 of the inner tube 22 . The proximal ends of the plurality of control elements 6C may be connected near the distal end 211 of the outer tube 21 .

The material of the plurality of control elements 6C is preferably rigid metal, resin, or the like so that the expanded diameter of the balloon 3 during expansion can be stably maintained at the intermediate diameter Rmid. In consideration of the followability of the balloon 3 to the vessel 9, it is preferable to use a shape memory alloy such as a nickel-titanium alloy, a hard resin, or the like.

The plurality of control elements 6C may be radiopaque. In this case, since the position of the balloon 3 inside the body can be easily grasped during the operation, the balloon 3 can be arranged at an appropriate position for the target stenotic lesion. In addition, since the expanded diameter of the balloon 3 during the operation can be easily grasped, an external force can be applied to the plurality of control elements 6C so as to obtain the desired expanded diameter.

A plurality of control elements 6C may have the function of crushing or dissecting hardened stenosed lesions. In this case, it is preferable that the plurality of control elements 6C be made of a hard material and have pointed tips.

The shape of the plurality of control elements 6C is not limited to a columnar shape, and may be a prismatic shape (for example, a triangular prism). Hollows extending along the stretching direction may be formed inside the plurality of control elements 6C. That is, the plurality of control elements 6C may have a hollow shape.

When a plurality of control elements 6C are in a close state, the control elements 60A and 60B may not be in contact with each other, and a gap may be formed between them. In this case, the distance between the control elements 60A and 60B in the distant state should be larger than the distance between the control elements 60A and 60B in the close state.

The plurality of control elements 6C may not be arranged at equal intervals in the circumferential direction in the separated state. For example, the distance between a pair of control elements 61, 62, 63 may be shorter or longer than the distance between other control elements.

A plurality of control elements 6C may be provided only in part of the expansion region 3B of the balloon 3 in the stretching direction. In this case, the plurality of control elements 6C can vary the expanded diameter of the balloon 3 for each region in the extending direction.

The balloon 3 may be coated with the drug only on part of the side surface 30 . Different agents may be applied to the second exposed portions 31B, 32B, 33B of the balloon 3, respectively. The sides 30 of the balloon 3 may not be coated with the drug. The hardness of the plurality of control elements 6C may be the same as the balloon 3 or may be softer than the balloon 3.

In the balloon catheter 1A, magnetic force or electrostatic force may act as an attractive force between all the control elements 60A and 60B while no external magnetic field acts on the plurality of control elements 6C. When the compressed fluid is supplied to the balloon 3 in this state and the balloon 3 is inflated, the balloon 3 may be in an intermediate diameter state. On the other hand, in the balloon catheter 1A, the magnetic force or electrostatic force between all the control elements 60A and 60B may be nullified with the external magnetic field acting on the plurality of control elements 6C. In this state, when the balloon 3 is inflated by being supplied with the compressed fluid, the balloon 3 may be in the maximum diameter state.

1A, 1B, 1C: balloon catheter 3: balloon 6: diameter control members 6C, 6D, 6E, 6F: control elements 30A, 31A, 32A, 33A: first exposed portions 30B, 31B, 32B, 33B: second exposed portions 661, 671: concave portions 662, 672: convex portions G: guide wire Q: both ends

Claims (16)

a balloon expandable and retractable between an expanded state and a contracted state;
A diameter control member for controlling an expansion diameter, which is the diameter of the balloon in the expanded state,
having a plurality of control elements each fixed at a different location on the balloon in the circumferential direction;
A separated state in which each of the plurality of control elements is separated from each other in the circumferential direction, and a close state in which the distance between at least two sets of at least two control elements is smaller than the separated state, is defined between the at least two control elements. switches according to changes in the external force acting on
In the separated state, the balloon is set to a maximum diameter state in which the expanded diameter is the maximum diameter,
A balloon catheter according to claim 1, further comprising the diameter control member that brings the balloon into an intermediate diameter state in which the expanded diameter is smaller than the maximum diameter in the approximated state. The plurality of control elements includes four or more control elements,
2. The balloon catheter of claim 1, wherein in the approximated state the distance between two or more sets of two control elements is less than in the separated state. The plurality of control elements are
3. The balloon catheter according to claim 1, wherein the balloon catheter is arranged at equal intervals in the circumferential direction in the separated state. The at least two control elements are
4. A balloon catheter according to any one of claims 1 to 3, wherein in said approximated state they contact each other. the external force is the expansion force of the balloon;
The balloon catheter according to any one of claims 1 to 4, wherein the diameter control member controls the expanded diameter of the balloon by frictional force. The at least two control elements are
a first control element including a recess;
6. The balloon catheter according to claim 5, further comprising at least a second control element having a protrusion that can be fitted into the recess. the external force is an external magnetic field;
The balloon catheter according to any one of claims 1 to 4, wherein the diameter control member controls the expansion diameter of the balloon by magnetic force. 8. The balloon catheter according to claim 7, wherein said plurality of control elements are made of magnetic material. the external force is energization of the plurality of control elements;
The balloon catheter according to any one of claims 1 to 4, wherein the diameter control member controls the expansion diameter of the balloon by electrostatic force. 10. The balloon catheter according to claim 9, wherein said plurality of control elements are made of conductors or charged bodies. The plurality of control elements are
It has a cylindrical shape partially notched by a plane extending parallel to the axis,
In a cross section orthogonal to the axial center, an angle between two straight lines extending from the axial center toward both ends of the chord corresponding to the plane is within a range of 90° to 180°. The balloon catheter according to any one of claims 7 to 10. 12. The balloon catheter according to any one of claims 1 to 11, wherein at least part of said balloon is coated with a drug. The balloon is
a first exposed portion exposed in the intermediate diameter state;
a second exposed portion that is not exposed in the intermediate diameter state and is exposed in the maximum diameter state;
13. The balloon catheter according to claim 12, wherein different drugs are applied to the first exposed portion and the second exposed portion. 14. The balloon catheter of any of claims 1-13, wherein the plurality of control elements are stiffer than the balloon. the plurality of control elements being stiffer than the balloon;
13. The balloon catheter of claim 12, wherein said plurality of control elements are coated with said drug that is the same as said drug applied to said balloon. the plurality of control elements being stiffer than the balloon;
13. The balloon catheter of claim 12, wherein said plurality of control elements are coated with a drug different from said drug applied to said balloon.

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