JPH09108357A - Balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to measure blood pressure near a balloon indwelling part in the balloon catheter of a single lumen type which is relatively easy to be made to have narrow diameter. SOLUTION: This balloon catheter 1 is equipped with a catheter shaft 3, a balloon 5, a connector 9, an end chip 11, etc., a pressure sensor 13 which is able to measure circumference pressure is provided at the tip of the end chip 11, and a signal line 15 which can transfer an output signal from the pressure sensor 13 to a pressure monitor device M is provided in the hollow part of the catheter shaft 3. The signal line 15 has appropriate flexibility to an extent that prevents the balloon 5 and the catheter shaft 3 from being bent and also serves as a reinforcing material. A wrapping sheath 17 covering around the balloon 5 can be inserted into a blood vessel with a covered balloon as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balloon catheter inserted into a blood vessel for use.

[0002]

2. Description of the Related Art Conventionally, as a balloon catheter used for IABP (intra-aortic balloon pumping), a so-called double lumen type, as shown in FIG. 4 (a), is known.

In the case of this balloon catheter 101, as shown in FIG. 4 (a), the catheter shaft 103 has a structure in which an inner tube 103b is arranged in the inner cavity of an outer tube 103a, and an outer tube 103a and an inner tube 103b are provided. The first lumen 105a formed between the
Serves as a supply / discharge passage for gas supplied to the balloon 107, and is the second lumen 1 which is the inner cavity of the inner tube 103b.
05b is a passage for passing the guide wire. Further, since the second lumen 105b communicates with the blood vessel on the distal end side, the pressure in the second lumen 105b is measured on the proximal end side during use to measure the blood pressure near the balloon placement position. It has the advantage of being observable.

By the way, this type of catheter becomes an obstacle in the blood vessel and impedes the flow of blood to some extent. Therefore, the outer diameter of the catheter (hereinafter also referred to as the catheter diameter)
It is desirable to use a thinner catheter because it may cause a risk of blood circulation, especially in patients with a thin blood vessel or those with severe calcification of the blood vessel and narrowing of the blood vessel. Those with a diameter are desired. However, since the double-lumen type balloon catheter 101 has a double-tube structure in the catheter shaft 103, there is a limit in reducing the diameter, and the balloon catheter 101 has not been sufficiently thin.

On the other hand, as a balloon catheter having a catheter diameter smaller than that of the double lumen type, a single lumen type is conventionally known. The single lumen type balloon catheter 111 is
As shown in FIG. 4B, the catheter shaft 113 has only one lumen 115, and the lumen 115 serves as a gas supply / discharge passage for supplying gas to the balloon 117. Further, instead of having no lumen for passing the guide wire, a reinforcing wire 119 is arranged at the center of the catheter shaft 113 and the balloon 117 in order to prevent bending and the like at the time of inserting the blood vessel. With such a balloon catheter 111, the catheter diameter can be made smaller than that of the double-lumen type, and it can be used even when the blood vessel diameter is smaller.

[0006]

However, the single-lumen type balloon catheter 111 cannot measure blood pressure like the double-lumen type balloon catheter 101, and if some other means is not taken. There is a problem in that it is not possible to observe changes in blood pressure of patients undergoing treatment. Therefore, although the single-lumen type balloon catheter 111 is superior in that it is less likely to cause blood circulation disorder and can be used in patients with smaller blood vessel diameters, the double-lumen type balloon catheter 101 is actually used. Most cases were.

Therefore, an object of the present invention is to make it possible to measure the blood pressure in the vicinity of the balloon indwelling position in a single-lumen type balloon catheter whose diameter can be relatively easily reduced.

[0008]

In order to achieve the above-mentioned object, the present invention provides, as claimed in claim 1, an elongated tubular flexible catheter shaft and a distal end of the catheter shaft. A balloon catheter that is provided on the side of the balloon and that is inflated / deflated by a fluid supplied / exhausted through the lumen of the catheter shaft, in a blood vessel that is disposed near the balloon and in which the balloon is placed A pressure sensor capable of measuring the surrounding blood pressure with a signal transmission path that is connected to the pressure sensor and is guided to the outside through the catheter shaft and can transmit the output signal from the pressure sensor to an external device. It is characterized by having and.

Further, the balloon catheter according to the present invention is characterized in that the signal transmission path is made of a flexible member which is arranged so as to penetrate through the inside of the balloon and the catheter shaft in the axial direction. .

Further, in addition to the above structure, the balloon catheter according to claim 3 further comprises a wrapping sheath that covers the outer circumference of the balloon when the balloon is folded, and the wrapping sheath covers the balloon. It is characterized in that it can be inserted into the blood vessel together with the balloon as it is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the balloon catheter according to claim 1, the pressure sensor converts a pressure change into an analog signal and outputs the analog signal. A semiconductor strain gauge is preferable because it can be configured with a strain gauge or the like that can be detected as a change in resistance, and in particular, considering that it is relatively easy to miniaturize.

The signal transmission path may be any medium as long as it is a medium for transmitting a detection signal from the pressure sensor to an external device. When a strain gauge is used as the pressure sensor, for example, a conductive metal wire is used as a current source. It is only necessary to configure the forward and return routes. The metal wire is not limited to a linear shape, but a coil spring shape, a net shape, a foil shape, or the like can be used. Further, not only a metal wire, but also a coating film or the like having conductivity provided by a conductive material such as carbon can be used as a signal transmission path if it is formed on the inner surface of the catheter shaft or the like.

Further, as a pressure sensor used for invasive blood pressure measurement, in addition to an electric sensor such as a strain gauge,
Optical type using optical fiber is also known,
Even with this, it is possible to configure the pressure sensor and the signal transmission path. The external device may be any device as long as it has a function of converting the output signal from the pressure sensor into a blood pressure value and providing it to the user. More specifically, the blood pressure change is digitized or graphed. Examples of the display device include a display device capable of displaying information, a recording device for recording and outputting on recording paper, or a computer for comprehensively processing other information.

According to the balloon catheter thus constructed, the output signal from the pressure sensor arranged in the vicinity of the balloon can be transmitted to the external device through the signal transmission path, and the output signal can be transmitted to the external device. Can be processed and displayed or recorded. Therefore, even if there is no lumen communicating with the blood vessel, the blood pressure in the blood vessel in which the balloon is placed can be measured, so that the blood pressure can be measured even with a so-called single-lumen type balloon catheter. As a result, for example, even if it is applied to a patient with a small blood vessel diameter or a patient with severe calcification of the blood vessel and the inside of the blood vessel is narrowed, it does not cause blood circulation disorder, etc. Since it is not necessary to wear a device or the like, it is not troublesome and the physical burden on the patient is minimized. Further, even a patient with a large blood vessel diameter can maintain more blood flow, so that there is no concern of blood circulation disorder and the physical burden on the patient can be reduced.

By the way, as described in claim 2, when the signal transmission path is constituted by a flexible member arranged so as to penetrate through the inside of the balloon and the catheter shaft in the axial direction,
This member functions not only as a signal transmission path but also as a reinforcing material, and there is an effect that the bending of the balloon and the catheter shaft can be prevented without separately providing a reinforcing material or the like.

Further, when the wrapping sheath according to the third aspect is provided, the balloon can be inserted into the blood vessel while the balloon is covered with the wrapping sheath, so the wrapping is performed after the balloon portion is completely in the blood vessel. By removing the sheath, the balloon does not melt before entering the blood vessel, and melting does not make insertion difficult. In addition, the loosened balloon does not damage the skin at the insertion site and, conversely, does not damage the balloon. Furthermore, since the surface of the wrapping sheath can be a smooth surface with less unevenness as compared with a folded balloon, insertion into the human body is easier than with a balloon regardless of whether or not it is unraveled.

By the way, the balloon catheter according to claim 3 is particularly characterized in that the wrapping sheath has a structure which can be inserted into a blood vessel together with the balloon while covering the balloon. Specifically, the wrapping sheath is
At least an outer diameter that can be inserted into a blood vessel, sufficient flexibility that does not hinder the flexibility of a folded balloon, the tip side (distal end side) does not curl up during insertion, blood vessel It is required that the balloon can be easily removed after the insertion of the balloon into the inside is completed.

The above items cannot be specified by numerical values and the like because they differ depending on the blood vessel to be inserted and individual differences of patients, but the thinner the thinner, the better in order to suppress blood circulation disorders and the like as much as possible. Although the above cannot be specified numerically, the desired flexibility can be imparted to some extent by adjusting the material and wall thickness of the wrapping sheath, so that it is more desirable within the range that the required strength is secured. It is desirable to be able to flexibly deform.

With respect to the above, a method of adhering or closely adhering the distal end portion of the wrapping sheath to a member (for example, a balloon, a distal end tip, etc.) to be included can be considered. As a method of closely contacting, for example, the inside of the wrapping sheath is made airtight and sufficiently decompressed, the dimension of the wrapping sheath is set to be slightly smaller than the outer diameter of the folded balloon, and the balloon is pushed into the wrapping sheath. Alternatively, a method of forming the wrapping sheath with a heat-shrinkable resin material and applying heat to the tip side to shrink the wrapping sheath can be considered. Furthermore, if there is a step at the boundary between the wrapping sheath and the member included in the wrapping sheath on the tip side of the wrapping sheath, a force such as rolling up may be applied to the end of the wrapping sheath. If the shape of the member is adjusted to protect the end of the wrapping sheath, or if the shape of the end of the wrapping sheath is adjusted to prevent a large step at the boundary, the end of the wrapping sheath will be rolled up. It becomes difficult to apply strong force. In addition, when adhering or adhering, in consideration of removing the wrapping sheath later, it is necessary to adhere or adhering with a force such that the lapping sheath does not cause curling but can be removed.

With respect to the above, in the simplest case, the catheter shaft may be pulled out with the shaft as an axis. This requires that the rear end side of the wrapping sheath is exposed outside the body by a length sufficient to pull out the wrapping sheath when the balloon is inserted into the blood vessel. Further, in order not to damage the balloon and the wrapping sheath to each other when the balloon is pulled out, it is preferable that the frictional resistance between the wrapping sheath and the balloon is small.
The wrapping sheath pulled out through the axis of the catheter shaft can be removed from the catheter shaft by, for example, tearing or severing the catheter shaft. Therefore, it is desirable that the wrapping sheath has a structure that allows easy tearing or severing in advance.

In constructing the wrapping sheath that satisfies the above-mentioned conditions, the material is not particularly limited, but synthetic resin materials (for example, polyurethane) generally used for medical instruments can be used. ,
To make it particularly thin and soft, a fluororesin (for example, polytetrafluoroethylene resin (PTFE), tetrafluoroethylene-6-fluoropropylene copolymer resin (FE
P), tetrafluoroethylene-perfluoroalkylvinylether copolymer resin (PFA), tetrafluoroethylene-ethylene copolymer resin (ETFE), polytrifluoroethylene chloride (CTFE), polyvinylidene fluoride (PFV), etc. ) Should be used.

Further, in order to facilitate the insertion of the catheter into the body, it is better that the frictional resistance of the outer peripheral surface of the wrapping sheath is smaller, and in order to facilitate the pulling out of the wrapping sheath from the body, The smaller the frictional resistance of the inner peripheral surface, the better. However, in order to reduce such frictional resistance, the inner and outer peripheral surfaces of the wrapping sheath are made of a hydrophilic polymer (for example, polyvinyl alcohol, carboxymethyl cellulose, polyacrylic acid, sodium polyacrylate, polyacrylamide). , Polyhydroxyethyl methacrylate, polyvinyl methyl ether, polyvinyl pyridine, polyethylene oxide, polyvinyl pyrrolidone, etc.).

The main conditions for constructing the wrapping sheath according to the present invention have been specifically mentioned above. However, in addition to this, it is needless to say that the wrapping sheath is made of a material that does not adversely affect the human body. Is. In addition, for example, after determining the material and wall thickness, if it is determined that further flexibility is required, innumerable minute holes may be formed on the side surface of the wrapping sheath, or a plurality of grooves or slits may be provided. Good. Further, the flexibility is improved even when the wrapping sheath is not formed in a tubular shape but is in a band shape spirally wound around the balloon.

Further, for example, as a structure for preventing the wrapping sheath from curling up on the distal end side, in addition to the above-mentioned adhesion or close contact, a screw structure may be provided for joining, and torque may be applied to release the joining. is there. Furthermore, for example, as a means for removing the wrapping sheath, in addition to pulling out the wrapping sheath, for example, a material that dissolves in the blood vessel (for example, saccharides, starch, collagen,
Heparin, wafer, etc.) may be selected to form a wrapping sheath. This will dissolve and remove the wrapping sheath after insertion of the catheter. In this case, like the resin material described above, the wrapping sheath may be formed first and then attached to the balloon, but the material before molding is coated on the surface of the balloon and directly applied on the balloon. It is also possible to shape the wrapping sheath.

As described above, various specific structures can be considered for inserting the wrapping sheath into the blood vessel together with the balloon while covering the balloon, but in any case, the balloon can be inserted before insertion into the body. Since it cannot be unraveled, it has the effect that the balloon can be inserted into the body more smoothly than before.

[Specific Example] Next, in order to further clarify the embodiment of the present invention, a specific example of a balloon catheter to which the present invention is applied will be described with reference to the drawings. The specific examples described below are merely examples of the embodiments of the present invention, and the embodiments of the present invention are not limited to the specific examples illustrated below.

The balloon catheter 1 is of a so-called single lumen type, and as shown in FIG. 1 (a), it is a long tubular tubular shaft that can be flexibly bent, and the distal end side of the catheter shaft 3. A balloon 5 which is provided on the balloon 5 and is inflated / deflated by a fluid supplied / exhausted through the lumen of the catheter shaft 3, and an index which is provided on the proximal end side of the catheter shaft 3 and communicates with the lumen of the catheter shaft 3. A connector 9 having an aeration port 7, a tip 11 that can be bent flexibly and that is arranged on the tip side of the balloon 5, and a pressure sensor 13 that is arranged at the tip of the tip 11 and that can measure the ambient pressure. ,
One end is connected to the pressure sensor 13, the other end is led out from the connector 9, and a signal line 15 capable of transmitting an output signal from the pressure sensor 13 to the pressure monitoring device M is provided. As shown in FIG. 1B, a wrapping sheath 17 that covers the outer circumference of the balloon 5 is attached to the outer circumference of the balloon 5 in a folded state.

Among these structures, the pressure sensor 13 is a semiconductor strain gauge whose electric resistance changes according to the deformation caused by the pressure change. In addition, the signal line 15 is made of conductors that are insulated from each other and serve as a forward path and a return path for the current. The signal line 15 is arranged so as to penetrate through the inside of the balloon 5 and the catheter shaft 3 in the axial direction, and has flexibility to the extent that bending of the balloon 5 and the catheter shaft 3 can be prevented. In addition to the function of transmitting the signal from the pressure sensor 13, it also functions as a reinforcing material.

Furthermore, the wrapping sheath 17 has a structure which can be inserted into a blood vessel together with the balloon 5 while the balloon 5 is covered. More specifically, the wrapping sheath 17 is a bag-shaped thin and flexible film whose surface is coated with a hydrophilic polymer based on a fluororesin, as shown in FIG. 1 (b). ,
The front end 17a is narrowed to a tapered shape, while the rear end 17
A part of b is cut into two, and a plastic knob 19 is attached to the outermost end thereof. Further, a tear line 21 extends from the base of the tear portion toward the tip 17a, so that the tear line 21 is easier to tear than the other portions.

The tip 17a of the wrapping sheath 17 is in close contact with the outer periphery of the tip 11 as shown in FIG. 2 (a). To make such a close contact, the wrapping sheath 1
7, the tip 17a of the wrapping sheath 17 is narrowed down to be smaller than the outer diameter of the tip 11, and the tip 11 is pushed in to wrap the sheath 17.
Can be attached to the balloon 5.

Alternatively, instead of the structure shown in FIG. 2 (a), as shown in FIG. 2 (b), the diameter is partially reduced on the proximal end side 11b than on the distal end side 11a of the tip 11. To form a step, and the tip 17a of the wrapping sheath 17 is
Located on the proximal end side 11b of the step and on the distal end side 1 of the step
The diameter may be smaller than 1a.

With the structure of the present balloon catheter 1, the catheter diameter can be set to about 6 to 8 Fr (1.8 to 2.4 mm), depending on the diameter of the signal line 15. This is the same catheter diameter as the conventional single lumen type, and double lumen type (catheter diameter: 9 to 11 Fr (3.0 to 3.3 m
Since the second lumen required in m)) and the partition wall for separating the first and second lumens are both unnecessary, the diameter can be reduced.

Next, a method of using the present balloon catheter 1 will be described. First, the balloon catheter 1 is prepared for insertion by a procedure similar to a general sheathless insertion method. That is, one stopper is attached to the indeflation port 7 (see FIG. 1A) of the balloon catheter 1, and the inside of the balloon 5 is kept in a negative pressure by sucking it with the injection cylinder through the one stopper. Then, a puncture needle is used to puncture a blood vessel (for example, a femoral artery), a guide wire is inserted through the lumen of the puncture needle, and the puncture needle is pulled out. Next, the dilator is inserted along the guide wire, the punctured hole is sufficiently widened, and the guide wire and the dilator are pulled out.

Here, in the case of the conventional balloon catheter, the wrapping sheath is removed at least before it is inserted into the human body.
As shown in (a), it is introduced from the skin 31 into the blood vessel 33 while the wrapping sheath 17 is covered. In the balloon catheter 1, unlike the conventional balloon catheter, the tip 17a of the wrapping sheath 17 is structured so as not to be rolled up, so that the wrapping sheath 17 does not get caught on the skin 31 or the like.

In this way, the balloon catheter 1 is inserted by such a length that the balloon 5 can be sufficiently inserted into the blood vessel 33. In this state, the wrapping sheath 17 has a length sufficient to be pulled out of the skin 31. Exposed. Therefore, if the wrapping sheath 17 is grasped and pulled out toward the operator's side, only the wrapping sheath 17 can be pulled out of the body. The pulled-out wrapping sheath 17 can be removed from the catheter shaft 3 by tearing the knob 19 outward with both hands as shown in FIG. 3 (b).

After that, like the conventional single-lumen type balloon catheter, the balloon 5 is pushed to a desired position (for example, in the aorta) and connected to a well-known air driving device to assist blood pressure. be able to. At this time, the blood pressure in the blood vessel in which the balloon 5 is placed is measured by the pressure sensor 13 and transmitted to the pressure monitoring device M via the signal line 15. Therefore, for example, even when the intended blood pressure is not maintained due to a sudden change in the patient's condition or an unexpected failure of the air drive device, it can be immediately detected.

Although specific examples of the present invention have been described above, various modes other than the above specific examples can be adopted as the specific configuration of the present invention. For example, as a specific example, the one provided with the balloon 5 and the wrapping sheath 17 that can be inserted into the blood vessel is shown, but of course, a wrapping sheath similar to the conventional one may be provided.

Further, as a specific example, the signal line also serves as a reinforcing material for the balloon and the catheter shaft. However, in addition to the same reinforcing material as the conventional one, the signal line may be separately provided. You can also In this case, the inside of the lumen of the catheter shaft may become slightly narrower, but it is still thinner than the double lumen type,
Moreover, there is an advantage that a material suitable as a reinforcing material and a material suitable as a signal line can be selected on a functional basis, and the range of material selection can be expanded.

[0039]

As described above, according to the balloon catheter according to any one of claims 1 to 3, the blood pressure can be measured even with a single lumen type balloon catheter. Even if it is applied to patients with thin blood vessels or patients with severe calcification of the blood vessels and narrowing of the inside of the blood vessels, it does not cause blood circulation disorders, etc. Moreover, another blood pressure measuring instrument etc. is attached. Since it is not necessary, it is both labor-saving and the physical burden on the patient is minimal. Further, even a patient with a large blood vessel diameter can maintain more blood flow, so that there is no concern of blood circulation disorder and the physical burden on the patient can be reduced.

In particular, according to the balloon catheter of the second aspect, since the member serving as the signal transmission path also functions as a reinforcing material, the bending of the balloon and the catheter shaft can be prevented without providing a separate reinforcing material. It has the effect of being prevented. Furthermore, according to the balloon catheter of the third aspect, the balloon is not melted before entering the blood vessel, and there is no difficulty in insertion due to the melt. In addition, the loosened balloon does not damage the skin at the insertion site and, conversely, does not damage the balloon. Furthermore, since the surface of the wrapping sheath can be a smooth surface with less unevenness as compared with a folded balloon, insertion into the human body is easier than with a balloon regardless of whether or not it is unraveled.

[Brief description of the drawings]

FIG. 1 shows a specific example of a balloon catheter, (a)
[Fig. 4] is a front view of a state in which a wrapping sheath is removed, and (b) is a partial front view of a state in which the wrapping sheath is attached.

FIG. 2 is a partial cross-sectional view illustrating the structure near the tip of the wrapping sheath.

FIG. 3 is an explanatory view showing a part of a procedure for inserting a balloon catheter.

FIG. 4 shows a conventional balloon catheter, (a) is a front view of a double lumen type, and (b) is a front view of a single lumen type.

[Explanation of symbols]

1 ... Balloon catheter, 3 ... Catheter shaft, 5 ... Balloon, 7 ... Indeflation port, 9 ... Connector, 11 ... Tip tip, 1
3 ... pressure sensor, 15 ... signal line, 17 ... wrapping sheath, 19 ... knob, 21 ... tear line.

Claims (3)

[Claims] 1. A long and flexible tube-shaped flexible catheter shaft, and expansion / contraction by a fluid which is provided on the distal end side of the catheter shaft and is supplied and exhausted through the lumen of the catheter shaft. A balloon catheter provided with a balloon, the pressure sensor being arranged in the vicinity of the balloon and capable of measuring the blood pressure in the blood vessel in which the balloon is placed; A balloon catheter provided with a signal transmission path that is guided to the outside via a shaft and is capable of transmitting an output signal from the pressure sensor to an external device. 2. The balloon catheter according to claim 1, wherein the signal transmission path is made of a flexible member arranged so as to penetrate through the inside of the balloon and the catheter shaft in the axial direction. Balloon catheter. 3. The balloon catheter according to claim 1, further comprising a wrapping sheath that covers the outer circumference of the balloon when the balloon is folded, and the wrapping sheath keeps covering the balloon. A balloon catheter having a structure that can be inserted into a blood vessel together with the catheter.