Catheter, examination system and thrombus removing device

The present invention relates to a catheter, an examination system, and a thrombus removing device.

A catheter is a flexible tube with a diameter of approximately 2 mm and a length of approximately 1 m. The catheter can be inserted from a femoral artery and advanced to a target site such as the heart or the brain. When a contrast agent is supplied from the front end of the catheter, radiography can be performed.

A catheter through a hole of which a guide wire is passed has been known. When the catheter is inserted from a femoral region, first, the wire is first inserted in the femoral region, and then the catheter is sent out along the guide wire, whereby the catheter can be made to reach a target site.

For a thrombolytic treatment of heart and brain vessels, a catheter is inserted in the body, and a thrombolytic agent (urokinase) is released from a front-end portion thereof. Moreover, a thrombolytic treatment using a laser beam is also known. Since the laser beam is attenuated by blood vessels, several devices have been proposed.

In a thrombolytic treatment described in the following Patent Document 1, it has been described that attenuation of a laser beam can be suppressed by advancing a laser beam into a contrast agent while releasing the contrast agent from the front-end portion of a catheter, whereby a thrombus can be dissolved. It has been provided that the laser beam is emitted from a movable optical fiber through a hole provided in the catheter.

In a thrombolytic treatment described in the following Patent Document 2, it has been provided that a pulsed laser radiation is emitted from the front end of an optical fiber protruded from the front-end portion of a capillary tube to cause ultrasonic vibration, whereby a thrombus can be dissolved.

Patent Document 1: Japanese Patent Registration No. 322885 Patent Document 2: Japanese Translation of International Application (Kohyo) No. 2000-508938

Problem to be Solved by the Invention

Meanwhile, with a conventional catheter, since the distance between a laser beam and a thrombus is unclear, a large quantity of contrast agent has been used and a laser beam has been emitted depending on skill and intuition, and thus the laser beam could not be effectively irradiated onto a target such as a thrombus.

The present invention has been made in view of such a problem, and an object thereof is to provide a catheter which can effectively irradiate an object with a laser beam and an examination system and a thrombus removing device which can effectively dissolve a thrombus as the object.

Means for Solving the Problem

In order to solve the problem described above, a catheter according to the present invention includes: a resinous capillary tube having a hole to pass a wire therethrough; a marker attached to a front-end portion of the capillary tube; and an optical fiber which is buried in the capillary tube and whose position relative to the marker is fixed, wherein a position, in an optical fiber longitudinal direction, of a front-end face of the optical fiber is coincident with a position, in an optical fiber longitudinal direction, of a front-end face of the marker. The front end of the optical fiber can be approximated to such an extent as to contact a thrombus or up to a close range. In such a state, it becomes possible to dissolve a thrombus more safely by only irradiating a laser beam with a specific wavelength, a specific pulse width, and a repetition frequency from the optical fiber.

When the catheter is inserted from a femoral region, the wire is first inserted in the femoral region, and then the catheter is sent out along the wire, whereby the catheter is made to reach a target site. In this case, when radiography is performed, the marker is displayed on a screen. As the marker, a metal marker that absorbs X-rays is favorably used. Since the position of this metal marker relative to the optical fiber is fixed, the metal marker can be moved up close to the target site such as a thrombus. More specifically, since the distance between the target site and the front end of the optical fiber is known, it becomes unnecessary to use a large quantity of contrast agent and irradiate a laser beam depending on skill and intuition, and therefore an effective laser beam irradiation becomes possible.

It is preferable that the catheter further includes a resin material interposed between the optical fiber and the capillary tube. The resin material is also bent when the catheter is curved, to suppress trace elements in blood from entering. Therefore, deterioration of the optical fiber can be prevented.

An examination system having this catheter includes: the catheter; and a light source which emits light to be inputted to the optical fiber of the catheter. Here, it is preferable the light source is a laser light source, and a center wavelength λ, a pulse width T, and a repetition frequency f of the laser beam are set as follows:

520 nm≤λ≤590 nm

1 μsec≤T≤100 μsec

1 Hz≤f≤10 Hz

In this case, since the laser beam effectively acts for thrombolysis and does not act on vessel walls, a thrombus can be dissolved efficiently and safely in a short time.

Effects of the Invention

According to the catheter, examination system, and thrombus removing device of the present invention, a laser beam can be effectively irradiated onto a target, so that a thrombus being the target can be effectively dissolved.

FIG. 1 A longitudinal sectional view of a catheter.

FIG. 2 A sectional view along arrows II-II of the catheter shown in FIG. 1 .

FIG. 3 block diagram of an inspection system to which the catheter shown in FIG. 1 is connected.

1 . . . catheter, 2 . . . wire, 3 . . . hole, 5 . . . marker, 6 . . . optical fiber, 7 . . . branching adapter, 8 . . . connector, 9 . . . contrast agent introducing tube, 10 . . . connector, 11 . . . packing, 12 . . . terminal cap, 13 . . . connector, 61 a . . . ferule, 61 . . . optical fiber, DRV . . . drive circuit, DSP . . . display, INJ . . . contrast agent injector, LD . . . laser diode.

Hereinafter, a catheter, an examination system, and a removing device according to an embodiment will be described. Here, identical elements are designated with identical numerical symbols so as to avoid overlapping descriptions.

FIG. 1 is a longitudinal sectional view of a catheter.

A catheter 1 includes a resinous capillary tube 4 having a hole 3 to pass a wire 2 therethrough, a metal marker 5 attached to a front-end portion of the capillary tube 4 , and an optical fiber 6 which is embedded in the capillary tube 4 and whose position relative to the metal marker 5 is fixed.

The capillary tube 4 has a branching portion 4 a , and the hole 3 passes through one branched capillary tube 4 X and an optical fiber 6 passes through the other branched capillary tube 4 Y. The annular metal marker 5 made of a metal such as platinum is fitted to the front-end portion of the capillary tube 4 , and is thus fixed to the capillary tube 4 . The metal marker 5 may be formed by plating or vapor-depositing the resin capillary tube 4 with a metal material.

To a base-end portion of the branched capillary tube 4 X, a Y-type branching adapter 7 is fixed. The branching adapter 7 has a wire inserting through-hole 7 a and a contrast agent introducing through-hole 7 b , these through-holes 7 a and 7 b are connected at the branching capillary tube 4 X side to form a common through-hole 7 c , and this is connected with the hole 3 of the branched capillary tube 4 X. The branched capillary tube 4 X and the branching adapter 7 are coupled by a connector 8 .

A coupling portion 7 d at the branched capillary tube 4 X side of the branching adapter 7 has a screw portion 7 y at the periphery and includes, at the inside, a branched capillary tube insertion hole 7 x communicated with the common through-hole 7 c . A base-end portion 4 X 1 of the branched capillary tube 4 X is inserted in the branched capillary tube insertion hole 7 x , and the periphery of the base-end portion 4 X 1 has a screw portion 4 X 1 T.

The connector 8 forms a cap being a cylinder with a bottom, has a screw portion 8 a at the inner surface of its cylindrical portion, and has a screw portion 8 b at the inside of an opening of its bottom portion. When the connector 8 serving as a cap is screwed on, the screw portions 8 a and 8 b at the inside thereof are screwed with screw portions 7 y and 4 X 1 T formed on the periphery of the coupling portion 7 d and the periphery of the base-end portion 4 X 1 , whereby the branching adapter 7 is fixed to the branched capillary tube 4 X.

A connecting portion 7 e at the side of a contrast agent introducing tube 9 of the branching adapter 7 has a screw portion 7 f at the periphery and includes, at the inside, a contrast agent introducing tube insertion hole 7 g communicated with the contrast agent introducing through-hole 7 b . In the contrast agent introducing tube insertion hole 7 g , a base-end portion 91 of the contrast agent introducing tube 9 is inserted, and the periphery of the base-end portion 91 has a screw portion 91 T.

The connector 10 forms a cap being a cylinder with a bottom, has a screw portion 10 a at the inner surface of its cylindrical portion, and has a screw portion 10 b at the inside of an opening at its bottom portion. When the connector 12 serving as a cap is screwed on, the screw portions 10 a and 10 b at the inside thereof are screwed with the screw portions 7 f and 91 T formed on the periphery of the coupling portion 7 e and the periphery of the base-end portion 91 , whereby the contrast agent introducing tube 9 is fixed to the branching adapter 7 .

A wire inserting tail-end portion 7 h of the branching adaptor 7 has a screw portion 7 i at the periphery and includes, on its tail-end face, a packing 11 that blocks the wire inserting through-hole 7 a.

A tail-end cap 12 is a cylinder with a bottom, and has a screw portion 12 a at the inner surface of its cylinder portion. When the cap 12 is screwed on, the screw portion 12 a at the inside thereof is screwed with the screw portion 7 i formed on the periphery of the wire inserting tail-end portion 7 h , and the packing 11 is pressed against the wire inserting tail-end portion 7 h . The columnar-shaped packing 11 has a wire passing hole 11 a at the center, and the wire 2 passes through the wire passing hole 11 a.

To a base-end portion of the branched capillary tube 4 Y, another optical fiber 61 is connected via a connector 13 , and the optical fiber 61 within the branched capillary tube 4 Y is optically coupled with the optical fiber 61 . A ferrule 61 a is attached to the periphery of the optical fiber 61 . The connector 13 is composed of a connector body 13 X and caps 13 Y and 13 Z provided at both ends of the connector body 13 X. The connector body 13 X has a branched capillary tube insertion hole 13 a and a ferule insertion hole 13 b , and these insertion holes 13 a and 13 b are communicated within the connector.

A coupling portion 13 d at the branched capillary tube 4 Y side of the connector body 13 X has a screw portion 13 y at the periphery. In the branched capillary tube insertion hole 13 a , a base-end portion 4 Y 1 of the branched capillary tube 4 Y is inserted, and the periphery of the base-end portion 4 Y 1 has a screw portion 4 Y 1 T.

A cap 13 Y forms a cylinder with a bottom, has a screw portion 13 Ya at the inner surface of its cylindrical portion, and has a screw portion 13 Yb at the inside of its bottom portion. When the cap 13 Y is screwed on, the screw portions 13 Ya and 13 Yb at the inside thereof are screwed with screw portions 13 y and 4 Y 1 T formed on the periphery of the coupling portion 13 d and the periphery of the base-end portion 4 Y 1 , whereby the branched capillary tube 4 Y is connected to the connector 13 .

A coupling portion 13 e at the ferule side of the connector body 13 X has a screw portion 13 f at the periphery. In the ferule insertion hole 13 b , the ferule 61 a that includes the optical fiber 61 is inserted. A cap 13 Z forms a cylinder with a bottom, and has a screw portion 13 Za at the inner surface of its cylindrical portion. When the cap 13 Z is screwed on, the screw portion 13 Za at the inside thereof is screwed with the screw portion 13 f formed at the periphery of the coupling portion 13 e , whereby the ferule 61 a is fixed to the connector 13 . Therefore, the ferule 61 a and the branched capillary tube 4 Y are coupled by the connector 13 , and the optical fiber 61 and the optical fiber 6 within these respective portions are optically coupled.

Since a laser beam is introduced into the optical fiber 61 from a laser diode LD (light source), the laser beam is inputted to the optical fiber 6 , and is emitted from the front end of the catheter 1 .

When the catheter 1 is inserted in the body from a femoral region, the wire 2 that slides within the capillary tube 4 is first inserted in the femoral region, and then the catheter 1 is sent out along the wire, whereby the catheter 1 is made to reach a target site. In this case, when radiography of a front-end portion of the catheter is performed, the metal marker 5 is displayed on a screen of an X-ray apparatus.

The position of the metal marker 5 relative to the optical fiber 6 is fixed, and the metal marker 5 can be moved up close to the target site such as a thrombus. Although it is preferable that the position, in an optical fiber longitudinal direction, of a front-end face of the optical fiber 6 is coincident with the position, in an optical fiber longitudinal direction, of a front-end face of the metal marker 5 , the invention is not limited thereto. More specifically, since the distance between the target site and the front end of the optical fiber 6 is known by radiography, it becomes unnecessary to use a large quantity of contrast agent and irradiate a laser beam depending on skill and intuition, and therefore an effective laser beam irradiation becomes possible.

In other words, the front end of the optical fiber 6 can be approximated to such an extent as to contact the thrombus or up to a close range. In such a state, it becomes possible to dissolve the thrombus more safely by only irradiating a laser beam with a specific wavelength, a specific pulse width, and a repetition frequency from the optical fiber 6 .

Moreover, when radiography of the target site is performed, a contrast agent (iodine containing water-soluble contrast medium) is introduced via the contrast agent introducing tube 9 according to necessity, passed through the through-holes 7 b , 7 c , and 3 , and released from the front end of the catheter 1 . Also, when the contrast agent is introduced, it is preferable to withdraw the wire 2 from the capillary tube 4 of the catheter 1 .

FIG. 2 is a sectional view along arrows II-II of the catheter shown in FIG. 1 .

The optical fiber 6 is provided in a buried condition in the resinous capillary tube (body) 4 , and its longitudinal direction is coincident with a longitudinal direction of the capillary tube 4 . The center position of the optical fiber 6 is off the center position in a section vertical to the longitudinal direction of the capillary tube 4 , and the wire 2 passes through the inside of the hole 3 provided side by side with the optical fiber 6 . The capillary tube 4 is made of a material such as Teflon (registered trademark).

A resin material 14 is interposed between the optical fiber 6 and the capillary tube 4 . The resin material 14 is also bent when the catheter 1 is curved, to suppress trace elements in blood from entering the optical fiber 6 , so that deterioration of the optical fiber 6 can be prevented. The resin material 14 is an elastic material, which is formed of a silicone resin or the like. Here, without using the resin material 14 , the optical fiber 6 may be directly buried in the capillary tube 4 .

As a method for burying the optical fiber 6 , a method can be mentioned, which is for forming a capillary tube 4 opened with one hole by metallic molding, then passing an optical fiber 6 coated with an unsolidified resin material 14 through one narrow hole, and cutting a front-end portion of the capillary tube 4 along with the optical fiber 6 after the resin material 14 is solidified. Mechanical polishing is performed for this front-end portion.

Moreover, as another method, a method can be mentioned, which is for arranging an optical fiber 6 coated with a solidified resin material 14 and a molding wire such as a piano wire in a die for a capillary tube 4 , introducing a capillary tube forming material into this die and solidifying the material, then withdrawing the molding wire from the capillary tube 4 , and then cutting a front-end portion of the capillary tube 4 along with the optical fiber 6 . Mechanical polishing is performed for this front-end portion.

Further, as a method for branching the capillary tube 4 , a method for tearing one capillary tube up to halfway can be mentioned, besides the abovementioned metallic molding.

The optical fiber 6 is composed of a core 6 a made of silica glass and a clad 6 b located around the core 6 a . A laser beam that has passed through the core 6 a of the optical fiber 6 is emitted from the front-end face.

FIG. 3 is a block diagram of an inspection system to which the catheter shown in FIG. 1 is connected.

As described above, in this examination system, a thrombus can be dissolved more safely by only irradiating a laser beam with a specific wavelength, a specific pulse width, and a repetition frequency from the optical fiber 6 . More specifically, the present examination system functions mainly as a thrombus removing device. The present examination system includes the catheter 1 , the laser diode LD that emits a laser beam to be inputted to the optical fiber 6 of the catheter 1 , and a drive circuit DRV of the laser diode LD.

A center wavelength λ, a pulse width T, and a repetition frequency f of the laser beam has the following relationship.

Center wavelength λ: 532 nm(effective wavelength: 520 nm≤λ≤590 nm)

1 μsec≤T≤100 μsec

1 Hz≤f≤10 Hz

In this case, since the laser beam effectively acts for thrombolysis and does not act on vessel walls, a thrombus can be dissolved efficiently and safely in a short time. The power of the laser beam is set to 10 to 100 mJ.

Laser driving conditions of the drive circuit DRV are set by a controller CON. After the catheter 1 is inserted in the body, the wire 2 is withdrawn, and a contrast agent is released from the contrast agent injector INJ into the contrast agent introducing tube 9 according to necessity. The contrast agent injector INJ is controlled by the controller CON.

When an image of the thrombus and marker 5 (see FIG. 5 ) is obtained by an X-ray apparatus XI, this image data is transferred to a display DSP of the controller CON and displayed on the display DSP. Once the thrombus and marker 5 approximate to visually contact each other on the screen, the controller CON inputs a control signal to the drive circuit DRV to drive the laser diode LD by the abovementioned conditions. This allows dissolving the thrombus very safely and efficiently.

Although, in the above embodiment, a laser light source (laser diode LD) has been exemplified as the light source, the light source is not limited thereto and may be, for example, a light-emitting diode, a DPSS laser (Diode Pumped Solid-State Laser) or the like.

The present invention can be used for a catheter, an examination system, and a thrombus removing device.