Catheter for sucking foreign body

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to a foreign body suction catheter used for sucking and holding a foreign substance in a blood vessel such as a thrombus and removing it from the blood vessel.

【0002】

[Conventional technology]

Conventionally, as a catheter for removing a foreign substance such as a thrombus from the inside of a blood vessel, for example, as shown in FIG. 7, a storage unit having a suction port 102 for sucking the foreign substance B and accommodating the sucked foreign substance B. A foreign body suction catheter 106 having 104 at its tip is known. Since the foreign matter B is held in the decompressed storage portion 104 in the foreign matter suction catheter 106, there is little possibility that the foreign matter B will fall off during the extraction operation of the foreign matter suction catheter 106, which is excellent in this respect.

【0003】

[Problems to be Solved by the Invention]

However, in the foreign matter suction catheter 106, the outer diameter of the storage portion 104 has to be increased in order to store the foreign matter inside. Therefore, it could be used for large-diameter blood vessels such as pulmonary veins, but it is extremely difficult to insert it into blood vessels with a smaller diameter than pulmonary veins such as coronary arteries. Was virtually unusable.

【0004】

[Means for solving problems]

As a means for solving the above problems, the foreign body suction catheter of the present invention is a foreign body suction catheter having a tubular storage portion for storing the sucked foreign matter, and the outer diameter can be reduced or expanded and the outer diameter can be reduced or expanded. It is characterized in that the storage portion capable of maintaining the above-mentioned state and the expansion means for expanding the outer diameter of the storage portion are provided.

【0005】

[Action]

In the foreign body suction catheter having the above configuration, first, the foreign body suction catheter is inserted into the blood vessel in a state where the outer diameter is reduced by folding the storage portion along the axis, for example. Therefore, the foreign body suction catheter can be inserted into a blood vessel having a relatively small diameter. When the storage portion of the foreign body suction catheter reaches, for example, the vicinity of a thrombus, the outer diameter of the storage portion is expanded by the expanding means, and the outer diameter of the storage portion is maintained in the expanded state. After that, the thrombus is sucked and taken into the storage part, and the foreign body suction catheter is pulled out from the blood vessel with the thrombus housed in the storage part. In this way, even in a blood vessel having a relatively small diameter, foreign matter in the blood vessel can be removed by catheter operation.

【0006】

[Example]

Next, examples of the present invention will be described. (Example 1) As shown in FIG. 1, the foreign body suction catheter 10 of this example has a double structure of an outer tube 12 and an inner tube 14.

【0007】

The outer pipe 12 is made of a flexible synthetic resin, and has a structure in which a large-diameter storage portion 22 having a funnel-shaped tapered portion 18 and an opening 20 is joined to the tip of a relatively small-diameter conduit portion 16. Further, although not shown, a pump mechanism capable of depressurizing the inside of the outer pipe 12 is attached to the other end of the conduit portion 16.

【0008】

As shown in FIGS. 1 (b) and 1 (c), a metal wire 26 having a small diameter and plastically deformable is spirally built in the wall 24 of the storage portion 22. Therefore, when the storage portion 22 is deformed by applying an external force, the storage portion 22 maintains the deformed state by the action of the metal wire 26 that is plastically deformed in response to the external force.

【0009】

On the other hand, the inner tube 14 includes a thin tube 28, a balloon 30 provided at the tip of the thin tube 28, a thin tube 28, and a wire 32 inserted inside the balloon 30, and has a structure well known as a balloon catheter. Although not shown, a balloon operating mechanism is attached to the hand-side end of the inner tube 14, and the balloon 30 can be expanded and contracted and deformed via the balloon operating mechanism.

【0010】

In the inner tube 14, the thin tube 28 is inserted through the conduit portion 16, the hemispherical portion 30a and the body portion 30b on the thin tube 28 side of the balloon 30 are positioned in the storage portion 22, and the hemisphere portion 30c and the tip protrusion 30d on the tip side are It is stored in the outer tube 12 in a state of being exposed from the storage unit 22. The shape of the hemispherical portion 30a on the thin tube 28 side of the balloon 30 is substantially the same as the tapered portion 18 of the outer tube 12. Note that FIG. 1 shows a state in which the balloon 30 is inflated and movement of the balloon 30 to the conduit portion 16 side is restricted, but the balloon 30 in the contracted state can pass through the conduit portion 16.

【0011】

As shown in FIG. 2, in the foreign body suction catheter 10 having the above-mentioned structure, the storage portion 22 and the balloon 30 are folded before use, and the major axis d2 of the folded storage portion 22 is the outer diameter d1 of the conduit portion 16. Is almost the same as. At this time, the metal wire 26 plastically deformed by the external force accompanying the folding holds the storage portion 22 in the folded state. When the inside of the balloon 30 is inflated in the state of FIG. 2, the storage portion 22 is gradually expanded from the folded state according to the inflating of the balloon 30 and becomes tubular as shown in FIG.

【0012】

Next, a case where the foreign body suction catheter 10 is used will be described. First, as shown in FIG. 2, the storage portion 22 and the balloon 30 are placed in a folded state, and these are inserted into the blood vessel. By folding the storage portion 22 and the balloon 30, the outer diameter of this portion is reduced to approximately equal to the outer diameter of the conduit portion 16. Therefore, if the blood vessel into which the conduit portion 16 can be inserted, the foreign body suction catheter 10 Can be inserted. Further, since there is no radial protrusion, the foreign body suction catheter 10 can be easily inserted into the blood vessel. Further, since the tip protrusion 30d and the hemisphere portion 30c on the tip side function as a guide member, the insertion operation becomes easier.

【0013】

When the storage portion 22 reaches the vicinity of the affected portion where the thrombus has occurred, for example, the balloon 30 is inflated to expand the storage portion 22 in a tubular shape (see FIG. 1), and then the balloon 30 is contracted. Since the storage portion 22 is held in a tubular shape by the metal wire 26, the diameter of the storage portion 22 does not decrease as the balloon 30 contracts.

【0014】

After that, the thin tube 28 is moved to the operator side (direction of arrow S in FIG. 1) to pull the balloon 30 into the conduit portion 16. Further, the balloon 30 is moved in the direction of arrow S together with the thin tube 28, and the inner tube 14 is removed from the outer tube 12. As shown in FIG. 3, when the inner tube 14 is removed, the inside of the outer tube 12 becomes hollow. In this state, the pressure inside the outer pipe 12 is reduced via the pump mechanism. By this decompression, thrombus K is sucked, separated from the affected part, and moves into the storage part 22 through the opening 20. Further, by removing the outer tube 12 from the blood vessel while keeping the outer tube 12 in the decompressed state, the thrombus K held in the storage portion 22 can be removed from the blood vessel. The outer pipe 12 is removed with the outer diameter of the storage portion 22 enlarged. However, since the passage resistance of the storage portion 22 is particularly reduced due to the presence of the tapered portion 18, the outer pipe 12 must be removed. It's not difficult. Further, even if an external force in the direction of reducing the diameter of the storage portion 22 acts due to contact with the blood vessel wall, the diameter on the opening 20 side, which has relatively little resistance to the force in the reduction direction, is reduced. It is effective in preventing the thrombus K from coming off from the storage portion 22.

【0015】

As described above, in the foreign body suction catheter 10 of the present embodiment, the storage portion 22 and the balloon 30 can be folded to reduce the outer diameter of this portion to substantially the outer diameter of the conduit portion 16, so that the conduit portion 16 can be inserted into the blood vessel. If so, the foreign body suction catheter 10 can be inserted. Therefore, it can be used for blood vessels having a relatively small diameter such as coronary arteries, and the range of application for thrombectomy by a catheter can be expanded.

【0016】

Further, as shown in FIG. 4, an oversheath 40 having a variable axial relative position to the outer tube 12 can be attached to the outer tube 12 on the outside. When this oversheath 40 is attached, the oversheath 40 is relatively moved in the direction of arrow X from the state shown in FIG. 4 (a), and as shown in FIG. 4 (b), the storage portion 22 is pressed to reduce the outer diameter of the storage portion 22. It can be reduced. Therefore, for example, when the storage unit 22 storing the thrombus K is used in the blood vessel when the outer tube 12 is removed from the blood vessel after sucking the thrombus K, the storage unit 22 is as shown in FIG. 4 (b). Is covered with an oversheath and pressed to reduce the outer diameter of the storage unit 22 so that it can be easily removed from the blood vessel. The oversheath 40 also has a function as a guide tube when the foreign body suction catheter 10 is inserted into the blood vessel. When the storage portion 22 is covered with the oversheath 40, the tips of the two do not necessarily have to match. (Example 2) The foreign body suction catheter 50 of this example is an example in which the outer diameter of the storage portion 52 is enlarged or reduced by expansion and contraction. The foreign body suction catheter 50 has a double structure provided with an inner tube similar to that shown in Example 1, but the illustration and description of this inner tube will be omitted.

【0017】

As shown in FIG. 5, in the foreign body suction catheter 50, the storage portion 52 provided at the tip of the conduit portion 56 of the outer tube 54 is made of stretchable silicone rubber, and is contained in the wall 58 of the storage portion 52. A plurality of plastically deformable metal wires 60a to 60e are bent in a lightning-like shape and sealed along the circumferential direction as shown in the figure.

【0018】

When a balloon (not shown) is inflated in the storage portion 52, the wall 58 is expanded by the expansion pressure of the balloon and the diameter of the storage portion 52 is expanded. In addition, the metal wires 60a to 60e are plastically deformed as the wall 58 is stretched (see FIG. 5 (c)). Since the vicinity of the metal wire 60e corresponds to the hemispherical portion of the balloon, it is deformed in a tapered shape. When the balloon is further contracted, the wall 58 tries to contract, but the plastically deformed metal wires 60a to 60e as described above hold the storage portion 52 in the state shown in FIG. 5 (c) against the contraction of the wall 58. ..

【0019】

The foreign body suction catheter 50 is inserted into the blood vessel in a state where the storage portion 52 is contracted. Since the subsequent operation procedure is the same as that of the first embodiment, the description thereof will be omitted. The foreign body suction catheter 50 of this embodiment can be inserted into the blood vessel in a state where the storage portion 52 is contracted and the outer diameter is substantially the same as that of the conduit portion 56. Catheter 50 can be inserted. Therefore, it can be used for blood vessels having a relatively small diameter such as coronary arteries, and the range of application for thrombectomy by a catheter can be expanded.

【0020】

In the foreign body suction catheter 50, for example, as shown in FIG. 6, if a balloon 62 having a shape in which the outer diameter gradually increases from the vicinity of the opening 52a of the storage portion 52 is used, the shape of the storage portion 52 near the opening 52a is used. Can be funnel-shaped. Therefore, as compared with the example shown in FIG. 5 and Example 1, the thrombus can be sucked more reliably. Further, even if the opening is made in a funnel shape in this way, the force exerted from the blood vessel wall at the time of removing the foreign body suction catheter 50 acts in the direction of closing (reducing) the opening 52a, so that there is no inconvenience at the time of removal.

【0021】

Further, as in the first embodiment, the outer tube 54 is removed with the outer diameter of the storage portion 52 expanded, but the passage resistance of the storage portion 52 due to the presence of the tapered portion formed near the metal wire 60e. Is particularly reduced, so it is not difficult to remove the outer tube 54. Further, even if an external force in the direction of reducing the diameter of the storage portion 52 acts due to contact with the blood vessel wall, the diameter on the opening 52a side, which has relatively little resistance to the force in the reduction direction, is reduced. It is effective in preventing the blood clot from coming off from the storage portion 52. It is also possible to attach an oversheath as in Example 1, and the effect of the oversheath is the same as in Example 1.

【0022】

Although the two examples have been described above, the present invention is not limited to these examples, and can be variously implemented without departing from the gist of the present invention. For example, the metal wire can have an appropriate shape such as a mesh shape in addition to a spiral shape or a lightning bolt shape, but it is not always required to have an orderly shape as in these examples. Alternatively, instead of the metal wire, a plastic wire that can be plastically deformed or the like can be used. Further, if the storage portion itself is made of a plastically deformable material, it is not necessary to use a metal wire, a plastic wire, or the like.

【0023】

Further, instead of the metal wires of Examples 1 and 2, a shape memory alloy that changes its shape in the direction of expanding the outer diameter of the storage portion at a temperature slightly higher than the body temperature is used, and the shape memory alloy is used, and the shape is passed through the outer tube. Alternatively, if the outer diameter of the storage portion is expanded by passing an electric current through the shape memory alloy itself to heat it, the balloon becomes unnecessary. Further, it is also possible to make this shape memory alloy into a two-stage shape memory alloy in which the outer diameter is expanded at a temperature higher than the body temperature and the outer diameter is reduced at a temperature below the body temperature. If this two-stage type is adopted, the diameter of the storage portion can be reduced when the catheter is removed, the removal resistance can be reduced, and foreign matter can be prevented from falling out of the storage portion.

【0024】

Alternatively, the storage portion itself may be a shape memory plastic, and the outer diameter may be similarly enlarged.

【0025】

[Effect of the invention]

As described above, according to the foreign matter suction catheter of the present invention, foreign matter in the blood vessel can be removed by catheter operation even in a blood vessel having a relatively small diameter.

[Simple explanation of drawings]

[Figure 1]

It is explanatory drawing of the structure of the foreign body suction catheter of Example 1, FIG. 1 (a) is the cross-sectional view in the state which the outer diameter of the accommodating part was enlarged, and FIG. 1 (b) is the part A in FIG. 1 (a). An enlarged cross-sectional view, FIG. 1 (c) is a partially enlarged cross-sectional view taken along the line BB of FIG. 1 (a).

[Figure 2]

It is explanatory drawing of the state which the accommodating part was folded in the foreign body suction catheter of Example 1, FIG. 2 (a) is a front view near the accommodating part, and FIG. 2 (b) is an enlarged cross section by CC line of FIG. 2 (a). It is a figure.

[Fig. 3]

It is explanatory drawing of the state in which the thrombus was sucked by the foreign body suction catheter of Example 1.

[Fig. 4]

It is explanatory drawing when the oversheath was attached to the foreign body suction catheter of Example 1, FIG. 4A is a cross-sectional view in the state where the storage part was exposed from the oversheath, and FIG. 4B is over the storage part. It is sectional drawing in the state of covering and pressing with a sheath.

[Fig. 5]

It is explanatory drawing of the accommodating part of the foreign body suction catheter of Example 2, FIG. 5 (a) is the front view in the state which the accommodating part was contracted, and FIG. The cross-sectional view and FIG. 5 (c) are front views in a state where the storage portion is extended.

[Fig. 6]

It is an example figure at the time of using the balloon which changed the diameter in the foreign body suction catheter of Example 2.

[Fig. 7]

It is explanatory drawing of the conventional foreign body suction catheter.

[Explanation of symbols]

10, 50 ... Foreign body suction catheter, 22, 52 Storage part, 26, 60a ~ 60e Metal wire (outer diameter holding means), 30, 62 ... Balloon (expansion means), K ... Blood clot.