JP3139561B2 - Dilatation catheter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dilatation catheter for dilating a stenosis formed in a blood vessel to increase the flow rate of blood on the distal side of the stenosis.

[0002]

2. Description of the Related Art Conventionally, dilatation catheters of this type are roughly classified into over the wire.
e) a monorail system, a steerable system in which a guidewire and a dilatation catheter are integrated, and a perfusion system in which blood flows from the center to the periphery of the balloon when the balloon is inflated. First over
The wire method has become mainstream. In this dilatation catheter, as shown in FIG. 3, a guide wire insertion tube 2 is inserted into a hollow shaft 1 and a balloon 3 for expanding a stenosis in a blood vessel is provided at the distal end of the hollow shaft 1. The base 4 has a guide wire insertion port 5 and a balloon inflation port 6. The balloon 3 is an inelastic body, and is formed by expanding a synthetic resin such as polyethylene or polyethylene terephthalate so as to be inflated and contractible . The outer diameter of the balloon 3 when expanded is usually 2.0, 2.5, 3.0, or 3.0. 5,
It is set to 4.0 mm.

[0003] Since the balloon 3 is inelastic, the physician first determines the inner diameter of the blood vessel in the stenosis region from a contrast finding and selects a dilatation catheter equipped with the balloon 3 having a size suitable for the inner diameter of the blood vessel. I do. Next, the dilatation catheter is percutaneously inserted into the arterial system of the patient, the balloon is inserted into the stenosis part, and then the liquid is supplied from the balloon inflation port 6 to inflate the balloon 3 so that the stenosis part is outward. The treatment has been completed after dilation and confirming the enlarged inner diameter of the blood vessel by imaging.

[0004]

However, in the above-mentioned conventional dilatation catheter, the pressure at which the balloon 3 is inflated is detected, but the pressure at which the balloon 3 compresses the stenosis cannot be directly detected. Various problems exist. For example, it is not possible to confirm whether the balloon 3 is optimally compressing the stenosis, the optimal dilation of the stenosis is affected by individual differences among doctors, and as a result, if the dilatation is insufficient, restenosis may occur. And overexpansion can rupture the blood vessels, so inexperienced physicians cannot perform this procedure. An object of the present invention is to improve a conventional dilatation catheter to eliminate the above-mentioned problems.

[0005]

To achieve the above object, a dilatation catheter of the present invention comprises a dilatation catheter having a hollow shaft for dilating a stenosis in a blood vessel, wherein the balloon compresses the stenosis. a pressure sensor for detecting the pressure directly has a configuration the Attach the portion in contact with the narrowed portion of the balloon surface.

The pressure sensor includes a conductive rubber whose electric resistance changes according to pressure, and an elastic body sandwiched between a pair of electrodes, which converts a change in distance between electrodes due to pressure into a change in electric capacity. A piezoelectric element that generates a voltage by pressure or a dye capsule that breaks down by pressure and releases a built-in dye is used. When a dye capsule is used for the pressure sensor, an optical fiber that transmits the color of the dye emitted from the dye capsule is used as a conductor.

[0007]

In the dilatation catheter having the above structure, when the balloon is inflated to expand a stenosis in a blood vessel, a pressure sensor is interposed between the balloon and the stenosis to directly apply pressure for the balloon to press the stenosis. The pressure is detected and transmitted as a pressure signal via a conductor to the base of the hollow shaft.
This allows the physician to know the optimal dilation pressure at which the balloon will compress the stenosis, making it possible to easily succeed in the subsequent dilation of the stenosis. In this case, the pressure signal is different depending on the type of the pressure sensor. When the pressure sensor is a conductive rubber, the electric signal of electric resistance, and when the pressure sensor is an elastic body sandwiched between a pair of electrodes, the electric signal of electric capacitance. When the pressure sensor is a piezoelectric element, it is a voltage electric signal, and when the pressure sensor is a dye capsule, it is a color light signal. These pressure signals are then converted to pressure by a pressure detector connected to the base of the hollow shaft.

[0008]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. However, the present invention is not limited to these embodiments. Embodiment 1 The dilatation catheter of this embodiment is a conventional over-the-wire type dilatation catheter having a pressure sensor provided on a balloon. As shown in FIG. Is provided at the distal end of the hollow shaft 11 to provide a balloon 13 for expanding a stenosis in the blood vessel, and at a portion of the balloon 13 that comes into contact with the stenosis, the pressure at which the balloon 13 presses the stenosis is directly detected. A pressure sensor 14 is attached, a conductor 16 for transmitting a pressure signal generated by the pressure sensor 14 to a base 15 of the hollow shaft 11 is inserted into the hollow shaft 11, and a guide wire insertion port 17, a balloon inflation port 18 and pressure detection are inserted through the base 15. A mouth 19 is provided. Although illustration is omitted,
A pressure supply source (usually a diluted contrast agent) is connected to the balloon inflation port 18, and a pressure detector for converting a pressure signal from the pressure sensor 14 into pressure is connected to the pressure detection port 19.

The balloon 13 is made of a non-elastic body and is formed by expanding a synthetic resin such as polyethylene or polyethylene terephthalate so as to be able to expand and contract. The outer diameter when expanded is usually 2.0, 2.5, 3.0, 3.5, 4.0.
mm, and the outer diameter during contraction is set small enough to facilitate passage through the stenosis. In addition, since the coronary artery including the stenosis is bent, sufficient flexibility is provided.

The pressure sensor 14 is made of a material that does not emit a substance harmful to the living body. The thickness of the pressure sensor 14 is set to 50 μm or less at the maximum to facilitate passage through the stenosis, but is set to 10 μm or less. And preferably 5 μm.
It is even more preferable to set m or less. Pressure sensor 1
As the sensor 4, a sensor that transmits a detected pressure as an electric signal, for example, a conductive rubber, an elastic body sandwiched between a pair of electrode plates, a piezoelectric element, and the like are preferable. The conductor 16 is used to transmit the electric signal generated by the sensor. Use electric wires.

The conductive rubber pressure sensor 14 is a sensor in which fine powder of a conductive substance is uniformly contained in rubber, and the contact ratio between the fine powders increases according to the pressure with which the balloon 13 presses the stenosis. Since the electric resistance decreases in inverse proportion thereto, the pressure can be known by measuring the change in the electric resistance.

Since the capacitance of the elastic pressure sensor 14 held between the pair of electrode plates changes as the distance between the electrode plates changes due to the pressure, it is necessary to measure the change in the capacitance. Can tell the pressure.

The piezoelectric element pressure sensor 14 is made of a crystal such as quartz, Rochelle salt, barium titanate, or a piezoelectric element material such as polyvinylidene fluoride. Since the neutral charge in the crystal is biased and a voltage is generated on the crystal surface, the pressure can be known by measuring the change in the voltage.

In order to use the dilatation catheter having the above structure, first, since the balloon 13 is an inelastic body, the inner diameter of the blood vessel in the stenosis region is determined from a contrast finding, and a balloon having a size adapted to the inner diameter of the blood vessel is determined. 13 is selected. Next, the dilatation catheter is percutaneously inserted into the arterial system of the patient, and the balloon 13 is inserted into the stenosis to be fixed. Subsequently, a liquid is supplied from the balloon inflation port 18 to inflate the balloon 13, thereby expanding the stenosis part outward. At this time, the pressure sensor 14 directly detects the pressure between the balloon 13 and the stenosis portion, at which the balloon 13 presses the stenosis portion, and outputs the detected pressure as a pressure signal,
That is, the electric signal such as electric resistance, electric capacity, and voltage is transmitted to the base 15 of the hollow shaft 11 via the conductor 16. The doctor receives this pressure signal by a pressure detector connected to the pressure detection port 19 to know the pressure, and appropriately dilates the stenosis with an optimal dilation pressure. After that, the expanded inside diameter of the blood vessel is confirmed by imaging, and the treatment is terminated.

Embodiment 2 As shown in FIG. 2, the dilatation catheter of this embodiment uses a dye capsule for transmitting a detected pressure as a color optical signal as a pressure sensor 14, and a conductor for transmitting the optical signal. 16 uses an optical fiber. The distal end of the conductor 16 is inside the balloon 13.

The dye capsule pressure sensor 14 comprises a plurality of capsules containing dyes of different colors which are broken according to the strength of the pressure with which the balloon 13 presses the stenosis. Since the color of the dye emitted by the capsule is different, the pressure can be known by detecting the change in the color of the dye with an optical fiber. Other configurations and usage of the dilatation catheter are the same as those in the first embodiment.

Although the dilatation catheters of the above embodiments are all of the over-the-wire type, the present invention is not necessarily limited to this type, and other monorail types, steerable types and perfusion types can be used. Needless to say, it can be applied to

[0018]

As described above, according to the present invention, when a balloon is inflated to expand a stenosis in a blood vessel, a pressure sensor is interposed between the balloon and the stenosis, and the balloon compresses the stenosis. Since the pressure is directly detected and transmitted as a pressure signal to the base of the hollow shaft via a conductor, the doctor knows the pressure and can appropriately dilate the stenosis with the optimal dilation pressure. Accordingly, it is possible to eliminate individual differences among doctors in angioplasty, to prevent restenosis from occurring due to insufficient dilation, and to prevent blood vessel rupture due to excessive dilation, and to always provide the best therapeutic effect. Also,
Even a doctor with little experience in angioplasty can easily and safely perform the procedure.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a dilatation catheter according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a dilatation catheter according to a second embodiment of the present invention.

FIG. 3 is a partially cutaway front view showing an example of a conventional dilatation catheter.

[Explanation of symbols]

 Reference Signs List 11 hollow shaft 12 guide wire insertion tube 13 balloon 14 pressure sensor 15 base 16 conductor 17 guide wire insertion port 18 balloon inflation port 19 pressure detection port 1 hollow shaft 2 guide wire insertion tube 3 balloon 4 hollow shaft base 5 guide wire insertion port 6 balloon inflation port

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-54-36083 (JP, A) JP-A-62-5328 (JP, A) JP-A-60-24428 (JP, A) JP-A-60-1985 158833 (JP, A) JP-A-62-294928 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61M 25/00 A61B 5/00 101

Claims (5)

(57) [Claims] 1. A dilatation catheter comprising a hollow shaft and a balloon for expanding a stenosis in a blood vessel, wherein a pressure sensor for directly detecting a pressure at which the balloon compresses the stenosis is provided at a portion of the balloon surface which comes into contact with the stenosis. A dilatation catheter which is attached. 2. The dilatation catheter according to claim 1, wherein the pressure sensor is made of conductive rubber whose electric resistance changes with pressure. 3. The dilatation catheter according to claim 1, wherein the pressure sensor is an elastic body sandwiched between a pair of electrodes, and converts a change in distance between the electrodes due to pressure into a change in capacitance. 4. The dilatation catheter according to claim 1, wherein the pressure sensor comprises a piezoelectric element that generates a voltage by pressure. 5. The pressure sensor comprises a dye capsule which breaks down by pressure to release a built-in dye, and the conductor comprises:
The dilatation catheter according to claim 1, comprising an optical fiber for transmitting the color of the dye released from the dye capsule.