JPH0910215A - Ultrasonic catheter - Google Patents

Abstract

PURPOSE: To prevent the breaking of a shaft tip and to make the deviation of a driving shaft by the expansion and contraction of a catheter absorbed by fitting a housing to a locking member provided with elasticity on the inner side of the catheter freely rotatably and movably into the longitudinal axis directions of the catheter. CONSTITUTION: A coil-shaped elastic member 41 is connected to the tip of the housing 27 of a catheter tip and the elastic member 41 is extended to a catheter tip side. A projecting part 42 provided with the elasticity composed of elastomer is formed on the inner side at the tip side of the exterior shaft 2 of the catheter and is freely rotatably and loosely fitted to the recessed part 43 of the elastic member 41. Also, a member 14 provided with a contrast forming property is formed at the tip of the catheter, the catheter tip part 17 is fixed to a stricture part of the like inside a blood vessel by the fitting part of the exterior shaft 12 of the catheter and the coil-shaped elastic member 41 and the catheter tip 17 is connected with the housing 27 even when stress more than breaking strength is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic catheter used by inserting it into a body cavity such as a blood vessel or a blood vessel.

[0002]

BACKGROUND OF THE INVENTION Traditionally, the coronary arteries of the heart and other small blood vessels,
Alternatively, there is known an ultrasonic catheter which is inserted into a blood vessel such as a bile duct to display a cross-sectional image of a lumen and measure blood flow. In this ultrasonic catheter, for example, as shown in FIG. 1 or 2, the ultrasonic transducer 3 and the transducer 3 directly or with the ultrasonic reflection plate 4 are attached to the distal end of a hollow catheter shaft 2 inserted into a body cavity. A drive transmission shaft 6 that transmits a driving force to rotate, and a signal line 7 that connects the vibrator 3 and the external electric circuit 5.
There is known an ultrasonic catheter that incorporates a laser and scans an ultrasonic wave by mechanically driving a drive shaft by an external drive source 8. By the way, in general, a catheter is required to have a softer characteristic toward the tip end portion in order to enhance the running property in a blood vessel. Further, in order to know the position of the catheter, a contrasting property is added to the catheter body, and a flat plate or a ring-shaped or coiled metal having a contrasting property is provided at the tip portion. Therefore, the above catheter characteristics are required even in the ultrasonic catheter, but in the ultrasonic catheter,
As shown in FIG. 1 and FIG. 2, a rigid vibrator 3 or a reflector 4 and a metal piece 14 for contrast are provided at the tip. Further, the portion 12 of the catheter shaft 2 for transmitting and receiving ultrasonic waves.
Must be made of a material with excellent ultrasonic permeability and thin. Therefore, the distal end portion of the ultrasonic catheter shaft has a low mechanical strength, and tensile breakage easily occurs.
This causes a problem that when the ultrasonic catheter is inserted into a blood vessel or the like, the catheter tip portion is broken and left inside the blood vessel.

Japanese Patent Laid-Open No. 5-507219 discloses an ultrasonic catheter in which a rigid housing is fixed to the distal end of the catheter sheath shaft. In this catheter, the fixed member at the tip of the catheter and the rotating part are rotatably joined with a lock pin, but the rigidity is poor due to the rigid housing, and expansion and contraction of the catheter due to bending is sufficient with the drive shaft and lock pin. There is a problem that it cannot be absorbed.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure for preventing breakage of the distal end portion of the ultrasonic catheter shaft and absorbing displacement of the drive shaft due to expansion and contraction of the catheter.

[0005]

The object is to incorporate a drive shaft for transmitting a mechanical drive force from the proximal side to the distal side in a catheter used by being inserted into a body cavity, and the distal side of the drive shaft. An ultrasonic catheter having a housing provided with an ultrasonic transducer and / or an ultrasonic reflecting plate inside the catheter, and having a mechanism for rotating and scanning the housing by the drive shaft, wherein the catheter is provided at a distal end portion of the housing. An elastic member extending toward the distal end side is provided, a locking portion is provided on the elastic member, and the housing moves in the longitudinal axis direction of the catheter to the elastic locking member provided inside the catheter at the locking portion. Achieved by an ultrasonic catheter characterized by a possible and pivotable fit.

Further, the engagement of the engaging portion of the elastic member and the engaging member of the catheter is such that the drive shaft is 0.5 to 0.5 in the longitudinal direction.
It is preferably formed so as to be movable by 20 mm.

Further, it is preferable that the tensile breaking strength of the fitting between the locking portion of the elastic member and the locking member inside the catheter is 0.4 kgf or more.

Further, it is preferable that the elastic member is a coil-shaped member.

Further, it is preferable to use a super elastic metal for at least a part of the elastic member.

Further, it is preferable that the elastic member has a smaller diameter toward the distal end side of the catheter.

Further, it is preferable that a substantially circular, hemispherical or spherical member having a larger diameter than the outer diameter of the tip is provided at the tip of the elastic member.

Further, it is preferable to provide an elastic member at the tip of the catheter.

Further, it is preferable to use a coil-shaped member as the elastic member provided at the distal end portion of the catheter.

Further, it is preferable to use a super elastic metal for at least a part of the elastic member provided at the distal end of the catheter.

Further, a locking portion is provided inside the elastic member provided at the distal end portion of the catheter, and is rotatably fitted to the locking portion of the elastic member provided at the distal end side of the housing. Is preferred.

[0016]

【Example】

(Embodiment 1) FIGS. 3 and 4 show an ultrasonic catheter 10 according to Embodiment 1 of the present invention. FIG. 3 is a view showing an axial cross section of the ultrasonic catheter of the present invention and a system configuration. FIG.
[Fig. 3] is a partial axial cross-sectional view showing a hand operation unit and an external unit of the ultrasonic catheter of the present invention. Next, the structure of the ultrasonic catheter of the present invention will be described. A housing 27 having a transducer 11 for transmitting and receiving ultrasonic waves is built into the distal end side of the exterior shaft 2 of the catheter, and the housing 27 is connected to the distal end of a coil-shaped drive shaft 6. The drive shaft 6 has a signal line 7 built-in, the catheter tip side of the signal line 7 is connected to a transducer formed on the transducer 11, and the hand side is the terminal 2 of the hand operation unit 20.
1 and 22 are connected. The hand operation unit 20 is detachably connected to the fitting unit 25 of the external unit 13. The terminals 21 and 22 in the hand operation unit 20 are electrically connected to the transmission / reception circuit 5 via a rotary sliding terminal 26 such as a slip ring, and the driving force from the motor 16 is transmitted to the drive shaft 6. , Terminals 23, 24 of the external drive source 8
And detachably connected. The external unit 13 includes a drive source 5 including a transmission / reception circuit 5 and a motor 16.
The external unit 13 is also electrically connected to the console 1 having a signal processing circuit and an image display device.

A coil-shaped elastic member 41 is connected to the distal end of the housing 27 at the distal end of the catheter, and the elastic member 4
1 extends toward the tip side of the catheter. On the tip side of the exterior shaft 2 of the catheter, an elastic convex portion 42 made of an elastomer of a resin such as urethane type, silicon type, and fluorine type is formed on the inner side, and is loosely rotatably loose with the concave portion 43 of the elastic member 41. It is fitted. A member 14 having a contrast property is formed at the tip of the catheter. The contrast member 14 is made of a resin such as a metal ring having a contrast property such as Pt or a mixture of tungsten powder having a contrast property. Catheter exterior shaft 12 and coiled member 41
The catheter tip portion 17 is fixed to the stenosis portion or the like in the blood vessel by the fitting portion, and the catheter tip portion 17 is connected to the housing 27 even when stress exceeding the breaking strength is applied. Note that, in FIG. 3, the locking portion is formed with a convex portion inside the exterior shaft 12 of the catheter and a concave portion on the coil-shaped member 41, but on the contrary, the exterior shaft 1 of the catheter is processed.
A concave portion may be formed on the inner side of 2, and a convex portion may be formed on the coil-shaped member 41.

The exterior shaft 2 of the catheter is made of a so-called catheter material such as a polyolefin-based, polyurethane-based, polyacetal-based, polyimide-based, or fluorine-based resin tube or stainless steel (SUS304, SUS31).
6 etc.) and the like, super elastic metal tubes such as NiTi, resin and stainless steel (SUS304,
(SUS316, etc.) is a composite tube in which a wire is coiled or braided and has a wall thickness of 30 to 300 μ.
m, and the tensile strength at break is preferably at least 0.4 kgf or more. Further, the ultrasonic wave transmitting / receiving portion 12 on the catheter tip side is preferably made of a resin such as a polyolefin-based, urethane-based, or fluorine-based resin having excellent ultrasonic permeability, and has a wall thickness of 10 to 10.
About 100 μm is preferable.

In the ultrasonic scanning of the ultrasonic catheter 10 of the present invention, the rotational movement of the motor 16 in the external unit 13 is controlled by the terminal 2 in the hand operation section 20 on the catheter side.
The ultrasonic waves transmitted and received by the transducer 11 provided in the housing 27 of the catheter 2 are transmitted to the drive shaft 6 via 1, 2 and 22, and the housing 27 fixed to the tip of the drive shaft 6 is rotated. It is performed by scanning in a substantially radial direction. The ultrasonic image obtained here is a cross-sectional image of a blood vessel or a blood vessel. Further, by moving the entire ultrasonic catheter 10 or the drive shaft 6 in the long axis direction, a longitudinal cross-sectional image of the blood vessel and the blood vessel can be obtained.

Next, a procedure for operating the ultrasonic catheter of the present invention in a blood vessel will be described. Not shown here.
As with the normal vascular catheterization procedure, an ultrasound catheter is first secured from outside the body using an introducer, etc., and then a guiding catheter for imaging, examination, or treatment catheter is selected and inserted using a guide wire. After reaching the target site to be inspected or treated, the ultrasonic catheter of the present invention is inserted into the guiding catheter to obtain a cross-sectional image of the blood vessel. At this time, the guide wire may be left inside the guiding catheter or may be pulled out of the body. In another procedure, the ultrasonic catheter of the present invention can be inserted and used in the guide wire lumen of a therapeutic catheter such as a balloon catheter. In this case, the outer diameter of the ultrasonic catheter is 0.25 mm to 0.97 mm and 0.35 m.
m to 0.46 mm is preferred.

FIG. 5 is a sectional view showing the structure of the transducer 11 provided in the housing 27 of the ultrasonic catheter 10 of the present invention. The oscillator 3 is a rectangular PZ
Electrodes 32 are formed on both surfaces of the piezoelectric body 31 such as T by vapor deposition, printing or the like. Here, the shape of the piezoelectric body 31 may be circular. On the back surface side of the vibrator 3, a resin material such as epoxy, urethane, acrylic resin or the like for absorbing and attenuating ultrasonic waves, or a back material 33 in which metal or inorganic powder is mixed with resin is provided. Here, as shown in FIG. 5A, the backing material 33 is provided with the unevenness 34 having a thickness difference D of λ / 4 (where λ is the wavelength in the backing material at the transmission frequency) on the back surface, so that the back surface is formed. Material 33
5B, or a low acoustic impedance layer 36 (Z = 1 × 10 ⁶ kg / m ^{2 s-} 8 × 10 ⁶ Kg / m ² s
) And the high impedance layer 37 (Z = 20 × 10 ⁶ kg / m ² s
The above may be a backing material in which the influence of reflected waves from the back surface of the backing material 33 is reduced by alternately laminating the above.

A so-called acoustic matching layer 35 is formed on the acoustic radiation surface of the vibrator 3 so as to have a thickness of λ / 4 (λ is the wavelength in the matching layer at the transmission frequency). Although only one layer is shown in this example, two or more layers may be provided.

(Embodiment 2) FIGS. 6, 7, and 8 show an ultrasonic catheter according to Embodiment 2 of the present invention. FIG. 6 is a partial axial cross-sectional view of the ultrasonic catheter distal end portion, and FIG. Top view,
FIG. 8 is a sectional view taken along line AA of FIG. Transducer 1
1 is fixed to the housing 27 with an adhesive or the like so that the ultrasonic wave transmitting / receiving surface is about ± 10 ° in the direction perpendicular to the long axis direction of the ultrasonic catheter 11. Housing 27
Has a joint strength of at least 0.0 at the tip of the drive shaft 6.
Bonded, brazed, and welded to 4 Kgf or more. The housing 27 has a pipe shape whose outer diameter is substantially equal to that of the drive shaft 6, and the fixing portion 18 of the transducer 11 is removed inside in a rectangular shape. The material may be metal, resin or ceramics, but stainless steel (SUS30) is used from the viewpoint of joining strength and reinforcement of the transducer 11.
4, SUS316, etc.) or a ceramic material is preferable.

A coil-shaped elastic member 41 made of a metal such as stainless steel (SUS304, SUS316, etc.), Pt, etc., or a resin such as polyacetal, etc. is connected to the tip of the housing 27 by adhesion, brazing, welding, etc. The concave portion 43 of the tubular member 41 is rotatably fitted to the convex portion 42 of the outer shaft, and the coil-shaped member 41 is movable about 0.5 mm to 20 mm in the longitudinal direction of the catheter. A spherical or hemispherical member 44 is connected to the tip of the coil-shaped member 41. The coil-shaped member 41 may be a single layer or a multi-layer, and the winding direction of the outermost layer coil is the direction tightened with respect to the rotation direction of the drive shaft. FIG. 6 shows a case of a single-layer coil, which is rotated clockwise.

The signal lines 7 are connected to the electrodes 32 on both sides of the vibrator 3. Although the signal line 7 is a twisted pair in FIG. 6, it may be a coaxial line.

In FIG. 6, the drive shaft 6 is formed by winding two flat layers of stainless steel (SUS304, SUS316, etc.) in two layers, and the breaking strength is 0.4 Kgf or more. The drive shaft 6 is also made of round wire or flat metal or resin.
It may be a coil wound or a blade wound in multiple layers, or a wire having a breaking strength of 0.4 Kgf or more and a signal wire horizontally wound.

At the connecting portion between the proximal side 15 and the distal side 12 of the exterior shaft of the catheter, the proximal side 15 is processed so that the distal end is thinner, and the distal side 12 is formed outside thereof. In this example, since the length of the connecting portion can be relatively long, the strength of the connecting portion is high, and mechanical properties such as flexibility and flexibility of the exterior shaft 2 of the catheter are sequentially changed from the proximal side 15 to the distal side 12. Can be done.

(Modification) FIGS. 9, 10, 11 and 1
2 and 13 show another modification of the present invention.

The tip 17 of the catheter is open in FIG. 6, but the tip 51 of the catheter may be closed as shown in FIG. When it is open, it is easy to prime the ultrasonic transmission fluid 9 in the catheter, and when it is closed, there is an advantage that blood does not flow into the catheter.

In the modification of FIG. 10, the coiled elastic member 4 is provided with a spherical or hemispherical circular member 45 having a larger outer diameter than the coil outer diameter at the tip of the coil whose outer diameter is uniform in the major axis direction.
1 is connected to the tip of the housing 27. The circular member 45 is rotatably connected to the convex portion 43 which is an elastic locking portion of the catheter exterior shaft.

Further, the modification of FIG. 11 shows a case where the coil-shaped elastic member 41 is made thinner toward the tip side.

In the modified example of FIG. 12, a round wire-shaped elastic member 46 of superelastic metal such as NiTi alloy is used so that the diameter becomes smaller toward the tip.

In the modified example of FIG. 13, a coil-shaped elastic member 52 is brazed to the distal end of the outer shaft of the catheter, or a coil-shaped elastic member 52 fixed with an adhesive 54 or the like is connected by adhesion or the like. A circular member 45 having a diameter larger than the outer diameter of the coil is fitted to the tip of the coil-shaped elastic member 41 connected to the tip of the housing 27 in the convex portion 48 of the member 52. The distal end of the exterior shaft 12 may be completely sealed by adhering the coil-shaped elastic member 52, but by preventing the adhesive 54 from entering the inner cavity of the coil-shaped elastic member 52, It is preferable that the ultrasonic transmission liquid such as physiological saline can flow out between the coils of the elastic member 52.
The coil-shaped elastic member 52 connected to the tip of the outer shaft 12 of the catheter is made of stainless steel (SU) having contrast properties.
S304, SUS316, etc.), Pt, Au, and other metals are preferable. The supporting member 53 is a metal having elasticity and is made of stainless steel (SUS304, SUS316).
Etc.), a super elastic metal made of a NiTi alloy material, or the like is preferable. Further, instead of the circular member 45, an uneven portion which is a locking portion of the coil-shaped elastic member may be fitted as in FIG.

FIG. 14 shows another modification of the exterior shaft of the ultrasonic catheter of the present invention. In this example,
The exterior shaft 15 on the hand side has a two-layer structure, and the tip side including the ultrasonic wave transmitting / receiving unit has a one-layer structure. Inner layer 48 on the hand side 15
Is a metal tube of stainless steel (SUS304, SUS316, etc.), a superelastic metal tube of NiTi alloy, etc., or a tube of stainless steel (SUS304, SUS316, etc.) wire wound by a coil or a blade, and the outer layer 49 is formed on the tip side. It is the same material such as polyolefin resin and fluorine resin. The outer layer 49 is formed by heat shrinkage,
It is carried out by a method of swelling with a solvent to coat the inner layer and then drying and shrinking, a dipping method, a melt extrusion molding method and the like.

[0035]

As described above, according to the present invention, the catheter used by being inserted into the body cavity has the built-in drive shaft for transmitting the mechanical driving force from the proximal side to the distal side, and the catheter is superposed on the distal side. An ultrasonic catheter having a housing provided with an acoustic wave oscillator and / or an ultrasonic reflection plate inside the catheter, and having a mechanism for directly or indirectly rotating and scanning the oscillator, the catheter being provided at a distal end portion of the housing. An elastic member extending toward the distal end side is provided, a locking portion is provided on the elastic member, and the housing moves in the longitudinal axis direction of the catheter to the elastic locking member provided inside the catheter at the locking portion. By allowing the catheter tip to rotatably and rotatably fit, the tip of the catheter fits into the housing even when stress exceeding the breaking strength is applied because the tip of the catheter is fixed to the stenosis in the blood vessel. And for that, it is possible to reduce the risk of leaving the body.

Further, since the housing allows the fitting portion between the housing and the catheter to move in the longitudinal direction of the catheter by about 0.5 mm to 20 mm, the bending of the catheter causes the drive shaft to expand and contract when the catheter expands and contracts. Can be prevented from being stretched or protruding beyond the tip of the catheter.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an axial sectional structure and system of a conventional ultrasonic catheter.

FIG. 2 is a sectional view of a part of the distal end of another conventional ultrasonic catheter in the axial direction.

FIG. 3 is a partial axial cross-sectional view of the ultrasonic catheter according to the first embodiment of the present invention and a system configuration diagram,

FIG. 4 is a partial axial cross-sectional view of a hand operation part and an external unit of the ultrasonic catheter according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing the structure of the transducer of the ultrasonic catheter according to the first embodiment of the present invention.

FIG. 6 is an axial cross-sectional view showing the distal end structure of the ultrasonic catheter according to the second embodiment of the present invention.

FIG. 7 is a top view of the distal end portion of the ultrasonic catheter according to the second embodiment of the present invention.

8 is an ultrasonic catheter of Embodiment 2 of the present invention shown in FIG.
FIG.

FIG. 9 is a diagram showing an ultrasonic catheter of a modified example of the present invention.

FIG. 10 is a diagram showing an ultrasonic catheter of a modified example of the present invention.

FIG. 11 is a diagram showing an ultrasonic catheter of a modified example of the present invention.

FIG. 12 is a diagram showing an ultrasonic catheter of a modified example of the present invention.

FIG. 13 is a view showing an ultrasonic catheter of a modified example of the present invention.

FIG. 14 is a diagram showing an ultrasonic catheter of a modified example of the present invention.

[Explanation of symbols]

1: Console 2, 12, 15, 48, 49: Exterior shaft (catheter) 3: Transducer 4: Reflector 5: Transmitter / receiver circuit
6: Drive shaft 7: Signal line 8: Drive source 9: Ultrasonic transmission liquid
10: Ultrasonic catheter 11: Transducer 13: External unit
14: Metal piece for contrast 16: Motor 17, 51: Catheter tip 1
8, 27: Housing 20: Hand operation part 21, 22, 23, 24: Terminal 2
5: Fitting part 26: Rotating / sliding terminal 31: Piezoelectric body 32: Electrodes 33, 34, 36, 37: Back material 35: Matching layer 41, 46: Housing tip elastic member 44, 45, 4
7: Tip member 42, 48: Convex portion 43: Recessed portion 52: Catheter tip elastic member 53: Support member 54: Adhesive portion

Claims (11)

[Claims] 1. A drive shaft for transmitting a mechanical drive force from a proximal side to a distal side is built in a catheter used by being inserted into a body cavity, and an ultrasonic transducer and / or an ultrasonic reflection is provided at the distal side of the drive shaft. An ultrasonic catheter having a housing provided with a plate in the catheter, the ultrasonic catheter having a mechanism for rotationally scanning the housing by the drive shaft,
An elastic member extending toward the distal end of the catheter is provided at the distal end of the housing, a locking portion is provided at the elastic member, and the housing is provided at the elastic locking member provided inside the catheter at the locking portion. An ultrasonic catheter characterized by being fitted so as to be movable and rotatable in the longitudinal direction of the catheter. 2. The engagement between the engaging portion of the elastic member and the engaging member of the catheter is such that the drive shaft is 0.5 to 20 m in the longitudinal direction.
The ultrasonic catheter according to claim 1, wherein the ultrasonic catheter is formed so as to be movable. 3. The ultrasonic catheter according to claim 1, wherein the tensile breaking strength of the engagement between the engaging portion of the elastic member and the engaging member of the catheter is 0.4 kgf or more. 4. The ultrasonic catheter according to claim 1, wherein the elastic member is a coil-shaped member. 5. The ultrasonic catheter according to claim 1, wherein a superelastic metal is used for at least a part of the elastic member. 6. The ultrasonic catheter according to claim 1, wherein the elastic member has a smaller diameter toward the distal end side of the catheter. 7. The ultrasonic catheter according to claim 1, wherein a substantially circular, hemispherical or spherical member larger than the outer diameter of the tip is provided at the tip of the elastic member. 8. The ultrasonic catheter according to claim 1, wherein an elastic member is provided at the tip of the catheter. 9. An ultrasonic catheter, wherein a coil-shaped member is used as the elastic member according to claim 8. 10. An ultrasonic catheter, wherein a superelastic metal is used for at least a part of the elastic member according to claim 8. 11. An engaging portion is provided inside the elastic member according to claim 9, and the engaging portion of the elastic member provided at the front end side of the housing according to claim 1 is rotatably fitted. The ultrasonic catheter according to claim 1, wherein: