Transcutaneous catheter

Abstract

To provide a percutaneous catheter capable of suppressing a burden on a patient's body, reducing a pressure loss of liquid circulating through a circulation circuit, and efficiently removing blood.SOLUTION: A catheter 30 includes a body part extending in an axial direction, and an expansion part 32 configured to be deformable in an expansion and contraction manner in a radial direction and provided with a plurality of extension pieces 33 along a circumferential direction so as to form gaps 30L therebetween. Each extension piece includes a top part 32B projecting in radially outward of the extension piece, and a proximal end opening 32H provided in at least one of the extension pieces and provided closer to a proximal end side than the top part.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a percutaneous catheter.

Background Art

[0002] Conventionally, for cardiopulmonary resuscitation, circulatory assistance, and respiratory assistance in emergency treatment, treatment by percutaneous cardiopulmonary support (PCPS) has been performed. This percutaneous cardiopulmonary support method is a method of temporarily assisting and substituting cardiopulmonary functions using an extracorporeal membrane oxygenation (ECMO) device.

[0003] The extracorporeal circulation device includes an extracorporeal circulation circuit composed of a centrifugal pump, an artificial lung, a blood extraction path, a blood delivery path, etc., and performs gas exchange on the extracted blood and delivers it to the blood delivery path.

[0004] In relation to this, for example, Patent Document 1 below describes a circulation circuit of an extracorporeal circulation device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When performing blood circulation in this circulation circuit, the blood is circulated by the force of a pump driven by a motor. Therefore, in order to suitably perform blood circulation, reduction of pressure loss in the blood extraction tube (percutaneous catheter) constituting the circulation circuit is required.

[0007] However, if the inner diameter of the blood extraction tube is small, the pressure loss will be high and the flow rate through the circulation circuit will decrease. Therefore, if the inner diameter of the blood extraction tube is not made sufficiently large, the required blood circulation volume cannot be obtained.

[0008] On the other hand, if the inner diameter of the blood extraction tube is increased, the outer diameter of the blood extraction tube will also increase. Therefore, if the inner diameter of the blood extraction tube inserted into the patient's body is increased, the degree of invasion to the patient's body will increase, and the burden on the patient's body will increase.

[0009] On the other hand, in the blood extraction tube, it is also required to extract blood more efficiently.

[0010] Therefore, an object of the present invention is to provide a percutaneous catheter that can suppress the burden on the patient's body, reduce the pressure loss of the liquid circulating in the circulation circuit, and extract blood more efficiently.

Means for Solving the Problems

[0011] The percutaneous catheter for achieving the above object is a percutaneous catheter having a lumen through which blood flows. The percutaneous catheter has a main body portion extending in the axial direction, and an expansion portion provided on the main body portion and configured to be radially expandable and contractible, and having a plurality of expansion pieces along the circumferential direction so that a gap portion is formed therebetween when expanded. Further, the expansion piece has a top portion protruding outward in the radial direction when expanded, and a proximal opening provided on at least one of the plurality of expansion pieces and provided on the proximal end side of the top portion.

Effects of the Invention

[0012] According to the percutaneous catheter configured as described above, when a dilator is inserted into the percutaneous catheter, the plurality of expansion pieces extend axially so as to close the gap provided between the plurality of expansion pieces, whereby the expansion portion contracts and the outer diameter of the percutaneous catheter becomes smaller. In this state, by inserting the percutaneous catheter into the living body, the burden on the patient's body can be suppressed. Further, after the percutaneous catheter is left in the living body, when the dilator is removed from the percutaneous catheter, the expansion portion expands in the radial direction. Therefore, the pressure loss of the liquid circulating in the circulation circuit can be reduced. Furthermore, since the proximal end opening is provided on the proximal end side rather than the top, the venous flow flowing from the proximal end side to the distal end side of the percutaneous catheter can be preferably drained. From the above, according to the percutaneous catheter configured as described above, it is possible to provide a percutaneous catheter that suppresses the burden on the patient's body, reduces the pressure loss of the liquid circulating in the circulation circuit, and can drain blood more efficiently.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope or the meaning of terms described in the claims. Also, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0015] FIG. 1 shows a schematic diagram of an extracorporeal circulation device applied to a percutaneous catheter according to an embodiment of the present invention, which is used as a percutaneous cardiopulmonary support method (PCPS) for temporarily assisting and substituting the functions of the heart and lungs until the cardiac function recovers when the patient's heart is weakened.

[0016] According to the extracorporeal circulation device 1, it is possible to perform a veno-arterial (VA) procedure in which a pump is operated to withdraw blood from a patient's vein (vena cava), gas exchange in the blood is performed by an artificial lung to oxygenate the blood, and then this blood is returned to the patient's artery (aorta) again. This extracorporeal circulation device 1 is a device for assisting the heart and lungs. Hereinafter, the procedure of withdrawing blood from a patient, performing a predetermined treatment outside the body, and then sending the blood back into the patient's body is referred to as "extracorporeal circulation".

[0017] As shown in FIG. 1, the extracorporeal circulation device 1 has a circulation circuit for circulating blood. The circulation circuit includes an artificial lung 2, a centrifugal pump 3, a drive motor 4 which is a driving means for driving the centrifugal pump 3, a venous side catheter (percutaneous catheter for blood withdrawal) 5, an arterial side catheter (blood delivery catheter) 6, and a controller 10 as a control unit.

[0018] The venous side catheter (blood withdrawal catheter) 5 is inserted from the femoral vein, and the tip of the venous side catheter 5 is placed at the right atrium or the transition part from the inferior vena cava to the right atrium through the inferior vena cava. The venous side catheter 5 is connected to the centrifugal pump 3 via a blood withdrawal tube (blood withdrawal line) 11. The blood withdrawal tube 11 is a pipeline for sending blood.

[0019] The arterial side catheter (blood delivery catheter) 6 is inserted from the femoral artery.

[0020] When the drive motor 4 operates the centrifugal pump 3 according to the command SG of the controller 10, the centrifugal pump 3 can withdraw blood from the blood withdrawal tube 11, pass the blood through the artificial lung 2, and then return the blood to the patient P via a blood delivery tube (blood delivery line) 12.

[0021] The artificial lung 2 is arranged between the centrifugal pump 3 and the blood delivery tube 12. The artificial lung 2 performs gas exchange (oxygen addition and / or carbon dioxide removal) on the blood. The artificial lung 2 is, for example, a membrane type artificial lung, and particularly preferably a hollow fiber membrane type artificial lung is used. Oxygen gas is supplied to this artificial lung 2 from an oxygen gas supply unit 13 through a tube 14. The blood delivery tube 12 is a pipeline connecting the artificial lung 2 and the arterial side catheter 6.

[0022] As the blood withdrawal tube 11 and the blood delivery tube 12, for example, pipelines made of synthetic resin with high transparency and elastic deformable flexibility such as vinyl chloride resin and silicone rubber can be used. Inside the blood withdrawal tube 11, the liquid blood flows in the V1 direction, and inside the blood delivery tube 12, the blood flows in the V2 direction.

[0023] In the circulation circuit shown in FIG. 1, the ultrasonic bubble detection sensor 20 is disposed in the middle of the blood extraction tube 11. The fast clamp 17 is disposed in the middle of the blood delivery tube 12.

[0024] The ultrasonic bubble detection sensor 20 detects the bubbles mixed into the circulation circuit when bubbles are mixed into the circulation circuit due to, for example, a malfunction of the three-way stopcock 18 or a breakage of the tube during extracorporeal circulation. When the ultrasonic bubble detection sensor 20 detects that there are bubbles in the blood sent in the blood extraction tube 11, the ultrasonic bubble detection sensor 20 sends a detection signal to the controller 10. Based on this detection signal, the controller 10 notifies an alarm by an alarm, reduces the rotational speed of the centrifugal pump 3, or stops the centrifugal pump 3. Further, the controller 10 commands the fast clamp 17 to immediately block the blood delivery tube 12 by the fast clamp 17. Thereby, it is prevented that the bubbles are sent into the body of the patient P. The controller 10 controls the operation of the extracorporeal circulation device 1 to prevent the bubbles from being mixed into the body of the patient P.

[0025] A pressure sensor is provided in the tube 11 (12, 19) of the circulation circuit of the extracorporeal circulation device 1. The pressure sensor can be mounted at any one or all of, for example, the mounting position A1 of the blood extraction tube 11, the mounting position A2 of the blood delivery tube 12 of the circulation circuit, or the mounting position A3 of the connection tube 19 connecting between the centrifugal pump 3 and the artificial lung 2. Thereby, when performing extracorporeal circulation on the patient P by the extracorporeal circulation device 1, the pressure in the tube 11 (12, 19) can be measured by the pressure sensor. Note that the mounting position of the pressure sensor is not limited to the mounting positions A1, A2, and A3, and any number can be mounted at any position of the circulation circuit.

[0026] Next, with reference to FIGS. 2 to 7, the configuration of the percutaneous catheter (hereinafter referred to as "catheter") 30 through which the dilator 50 is inserted will be described. FIGS. 2 to 7 are diagrams for explaining the configuration of the catheter 30. This catheter 30 is used as the venous side catheter (blood withdrawal catheter) 5 in FIG. 1.

[0027] As shown in FIG. 2, the catheter 30 has a main body portion 31 extending in the axial direction, an expansion portion 32 provided at the tip of the main body portion 31, a clamp tube 34 disposed on the proximal end side of the main body portion 31, a catheter connector 35 connecting the main body portion 31 and the clamp tube 34, and a lock connector 36.

[0028] In this specification, the side inserted into the living body is referred to as the "tip" or "tip side", and the side where the operator operates is referred to as the "proximal end" or "proximal end side". The tip portion means a certain range including the tip (the most distal end) and its periphery, and the proximal end portion means a certain range including the proximal end (the most proximal end) and its periphery.

[0029] As shown in FIG. 3, the catheter 30 has a lumen 30A penetrating from the tip to the proximal end. The gap portion 33L and the proximal end opening 33H (see FIG. 4) provided in the expansion portion 32 are configured to be disposed on the blood withdrawal target in the living body so as to perform blood withdrawal efficiently.

[0030] When inserting the catheter 30 into the living body, the dilator 50 shown in FIG. 2 is used. The dilator 50 is inserted into the lumen 30A of the catheter 30, and the catheter 30 and the dilator 50 are inserted into the living body in a state of being integrated in advance.

[0031] Hereinafter, each configuration of the catheter 30 will be described.

[0032] As shown in FIGS. 2 and 3, the main body portion 31 is configured to extend in the axial direction. As shown in FIG. 4, the diameter R1 of the opening 31A at the tip of the main body portion 31 is configured to be smaller than the outer diameter R2 on the proximal end side of the main body portion 31. According to this configuration, the outer diameter of the dilator 50 inserted into the catheter 30 can be reduced. Therefore, when inserting the catheter 30 and the dilator 50 into the living body in a pre-integrated state, the insertion resistance can be reduced. Furthermore, the followability with respect to the guide wire inserted through the dilator 50 can be improved.

[0033] As shown in FIGS. 2 and 3, the expansion portion 32 is provided at the tip of the main body portion 31. As shown in FIGS. 2 to 6, the expansion portion 32 is configured to be radially expandable and contractible. As shown in FIG. 4, the expansion portion 32 has a plurality of expansion pieces 33 provided along the circumferential direction such that a gap portion 33L is formed therebetween when expanded.

[0034] In the present embodiment, ten expansion pieces 33 are provided along the circumferential direction, but the number is not limited to ten. One expansion piece 33 is provided along the axial direction in a bent state when expanded. A gap portion 33L is formed between the ten expansion pieces 33. The gap portion 33L functions as a blood drainage hole.

[0035] As shown in FIG. 4, the expansion piece 33 has a first curved portion 33A, a top portion 33B, and a second curved portion 33C in order from the tip side.

[0036] As shown in FIG. 4, the first curved portion 33A is curved so as to protrude inward in the radial direction. According to this configuration, the step with the outer periphery of the dilator 50 can be reduced, and the expansion portion 32 can be preferably extended in the axial direction by the dilator 50.

[0037] As shown in FIG. 4, the first curved portion 33A has a closed shape. According to this configuration, as will be described later, when bloodletting, the blood that has entered from the proximal opening 33H of the second curved portion 33C collides with the first curved portion 33A and moves inside the lumen 30A of the catheter 30, so that bloodletting can be suitably performed.

[0038] Further, since the first curved portion 33A has a closed shape, recirculation can be reduced. Here, recirculation refers to a phenomenon in which when blood is drawn from a patient's vein (large vein), gas exchange in the blood is performed by an artificial lung to oxygenate the blood, and then when this blood is returned to the patient's artery (large artery) again, the oxygenated blood is drawn again. Recirculation generally occurs when blood flows from the distal end side to the proximal end side of the catheter 30 (see the rightward arrow in FIG. 7). However, in the catheter 30 according to the present embodiment, since the first curved portion 33A has a closed shape, the amount of blood flowing from the distal end side to the proximal end side of the catheter 30 moving into the lumen 30A of the catheter 30 can be reduced, and recirculation can be reduced.

[0039] The top portion 33B protrudes radially outward when the expansion portion 32 expands. The top portion 33B has a bent shape as shown in FIG. 4. According to this configuration, when the expansion portion 32 expands, the bent top portion 33B abuts against the blood vessel wall BW (see the leftward arrow in FIG. 7). Therefore, it is possible to prevent the proximal opening 33H provided on the proximal end side of the top portion 33B from sticking to the blood vessel wall, and bloodletting can be suitably performed from the proximal opening 33H.

[0040] The second curved portion 33C is curved so as to protrude inward in the radial direction, similarly to the first curved portion 33A.

[0041] As shown in FIG. 4, a proximal opening 33H is formed in the second bent portion 33C. The proximal opening 33H functions as a blood drainage hole. Generally, in a blood vessel, venous flow mostly flows from the proximal side to the distal side of the catheter 30 (see FIG. 7). Therefore, when the expansion portion 32 expands, the proximal opening 33H opens so as to face the proximal side, and thus blood can be preferably drained from the proximal opening 33H.

[0042] The proximal opening 33H has an elliptical shape with its axial direction as the major axis. According to this configuration, blood can be drained more preferably than with a circular proximal opening. Also, compared with a circular proximal opening, shear stress is less likely to be applied to the blood and red blood cells are less likely to be destroyed, so hemolysis can be suppressed.

[0043] In this embodiment, the blood drainage target is the inferior vena cava. The catheter 30 is inserted into the living body and retained so that the gap portion 33L and the proximal opening 33H of the expansion portion 32 are arranged in the inferior vena cava.

[0044] With the gap portion 33L and the proximal opening 33H of the expansion portion 32 arranged in the blood drainage target, the expansion portion 32 is arranged in the inferior vena cava, which is a relatively thick blood vessel, and the main body portion 31 is arranged in the femoral vein, which is a relatively thin blood vessel.

[0045] Also, when the dilator 50 is inserted into the lumen 30A of the catheter 30, the expansion portion 32 extends in the axial direction and its outer diameter and inner diameter become smaller as shown in FIGS. 5 and 6. At this time, the outer diameter of the expansion portion 32 becomes substantially the same as the outer diameter of the main body portion 31. With the expansion portion 32 extended in the axial direction and its outer diameter and inner diameter reduced, the catheter 30 can be inserted into the living body with less invasion.

[0046] Also, after the catheter 30 is retained in the living body, when the dilator 50 is removed from the lumen 30A of the catheter 30, the expansion portion 32 expands radially outward and its inner diameter becomes larger. Here, the expansion portion 32 is arranged in the inferior vena cava, which is a relatively thick blood vessel.

[0047] Here, the pressure loss in the expansion part 32 is the total length of the expansion part 32 × (average) passage cross-sectional area. That is, by increasing the inner diameter of the expansion part 32, the pressure loss in the expansion part 32 is reduced. When the pressure loss in the expansion part 32 is reduced, the flow rate of the blood flowing through the circulation circuit increases without increasing the rotational speed of the centrifugal pump. Therefore, in order to obtain a sufficient blood circulation volume, it is necessary to increase the inner diameter of the expansion part 32.

[0048] The inner diameter of the main body part 31 is, for example, 2.0 to 10.0 mm. Also, the inner diameter at the time of expansion of the expansion part 32 is, for example, 2.5 to 40.0 mm.

[0049] The materials constituting the main body part 31 and the expansion part 32 are not particularly limited, but polyethylene, polypropylene, PVC, perprene, nylon, polyurethane, PEEK, polyimide, and fluorine-based tubes can be used.

[0050] As shown in FIGS. 2 and 5, the clamp tube 34 is provided on the proximal end side of the main body part 31. Inside the clamp tube 34, a lumen through which the dilator 50 can be inserted is provided. The clamp tube 34 can be formed using the same material as the main body part 31.

[0051] As shown in FIGS. 2 and 5, the catheter connector 35 connects the main body part 31 and the clamp tube 34. Inside the catheter connector 35, a lumen through which the dilator 50 can be inserted is provided.

[0052] As shown in FIGS. 2 and 5, the lock connector 36 is connected to the proximal end side of the clamp tube 34. Inside the lock connector 36, a lumen through which the dilator 50 can be inserted is provided. On the outer surface of the proximal end side of the lock connector 36, a male screw part 36A provided with a thread is provided.

[0053] Next, the configuration of the dilator 50 will be described. Note that the configuration of the dilator 50 is not limited to the following configuration.

[0054] As shown in FIG. 2, the dilator 50 includes a dilator tube 51 that extends in the axial direction, a dilator hub 52 to which the proximal end of the dilator tube 51 is fixed, and a torsion ring 53 provided at the distal end of the dilator hub 52.

[0055] The dilator tube 51 is an elongated body that extends in the axial direction and has relatively high rigidity. The entire length of the dilator tube 51 along the axial direction is configured to be longer than the entire length of the catheter 30 along the axial direction. The dilator tube 51 is provided with a guide wire lumen 54 through which a guide wire (not shown) can be inserted. The dilator tube 51 is guided by the guide wire and inserted into the living body together with the catheter 30. After the catheter 30 is left in the living body, the dilator tube 51 is removed from the catheter 30 by pulling out the dilator hub 52 toward the proximal end side.

[0056] As shown in FIG. 2, the distal end of the dilator tube 51 is provided with a tapered surface 50a that abuts against the opening 31A at the distal end of the main body portion 31. The dilator tube 51 has relatively high rigidity and has a stiffness that enables the pushing force applied to the distal end side by the operation at hand to be transmitted to the main body portion 31.

[0057] The torsion ring 53 has a female screw portion (not shown) provided with a screw groove on the inner surface of the lumen. By screwing the female screw portion of the torsion ring 53 onto the male screw portion 36A of the lock connector 36, the dilator 50 can be attached to the catheter 30.

[0058] <Method of using the dilator> Next, with reference to FIGS. 2 to 7, the method of using the catheter 30 described above will be described. FIG. 2 shows a state before the dilator tube 51 of the dilator 50 is inserted into the lumen 30A of the catheter 30, and FIG. 5 shows a state after the dilator tube 51 is inserted into the lumen 30A of the catheter 30.

[0059] First, as shown in FIG. 5, the dilator tube 51 of the dilator 50 is inserted into the lumen 30A of the catheter 30. The dilator tube 51 sequentially passes through the inside of the main body portion 31 and the expansion portion 32, and the tapered surface 50a of the dilator tube 51 abuts against the opening 31A at the tip of the main body portion 31.

[0060] Here, as shown in FIG. 2, the total axial length of the dilator tube 51 is configured to be longer than the total axial length of the catheter 30 before the expansion portion 32 expands. Therefore, by inserting the dilator 50 into the catheter 30, the catheter 30 receives a force to extend in the axial direction, the expansion portion 32 extends in the axial direction, and preferably contracts radially inward.

[0061] Thereafter, the dilator 50 is attached to the catheter 30 by screwing the female screw portion of the screw ring 53 onto the male screw portion 36A provided on the lock connector 36 of the catheter 30.

[0062] Next, the catheter 30 through which the dilator 50 is inserted is inserted along a guide wire (not shown) that has been previously inserted into a target site in the living body. At this time, since the dilator 50 is inserted into the catheter 30, the outer diameter of the expansion portion 32 is substantially the same as the outer diameter of the main body portion 31, and the catheter 30 can be inserted into the living body with low invasiveness, and the burden on the patient's body can be suppressed.

[0063] Also, the catheter 30 is inserted into and retained in the living body until the gap portion 33L and the proximal end opening 33H of the expansion portion 32 are disposed in the right atrium or near the right atrium. In a state where the gap portion 33L and the proximal end opening 33H are disposed in the blood extraction target, the expansion portion 32 is disposed in the inferior vena cava, which is a relatively thick blood vessel, and the main body portion 31 is disposed in the femoral vein, which is a relatively thin blood vessel.

[0064] Next, the dilator 50 and the guide wire are removed from the catheter 30. At this time, the dilator 50 and the guide wire are first withdrawn to the location of the clamping tube 34 of the catheter 30 and clamped by forceps (not shown), and then completely removed from the catheter 30. When the dilator 50 is removed from the lumen of the catheter 30, the catheter 30 is released from the axially extending force received from the dilator 50. For this reason, the expansion part 32 contracts axially, and the inner diameter of the expansion part 32 increases. Thereby, the pressure loss in the expansion part 32 can be reduced and the flow rate of the required liquid can be ensured.

[0065] Next, the lock connector 36 of the catheter 30 is connected to the blood withdrawal tube 11 of the extracorporeal circulation device shown in FIG. 1. After confirming that the connection of the blood supply side catheter is completed, the clamp of the clamping tube 34 is released to start extracorporeal circulation.

[0066] At this time, as shown in FIG. 7, blood withdrawal is performed through the gap part 33L and the proximal end opening part 33H of the expansion part 32. According to the catheter 30 according to the present embodiment, since the first bending part 33A has a closed shape, recirculation can be suppressed.

[0067] When the extracorporeal circulation is completed, the catheter 30 is removed from the blood vessel, and the insertion site is hemostatically repaired by surgical techniques as necessary.

[0068] As described above, the catheter 30 according to the present embodiment is a catheter 30 having a lumen 30A through which blood flows. The catheter 30 includes a main body portion 31 extending in the axial direction, and an expansion portion 32 provided on the main body portion 31 and configured to be radially expandable and contractible, and having a plurality of expansion pieces 33 along the circumferential direction so that a gap portion 33L is formed therebetween when expanded. The expansion piece 33 has a top portion 33B protruding outward in the radial direction and a proximal end opening 33H provided on the proximal end side of the top portion 33B when expanded. When the dilator 50 is inserted into the catheter 30 configured as described above, the plurality of expansion pieces 33 extend in the axial direction so as to close the gap portion 33L provided between the plurality of expansion pieces 33, whereby the expansion portion 32 contracts and the outer diameter of the catheter 30 becomes smaller. In this state, by inserting the catheter 30 into the living body, the burden on the patient's body can be suppressed. Further, after the catheter 30 is left in the living body, when the dilator 50 is removed from the catheter 30, the expansion portion 32 expands in the radial direction. Therefore, the pressure loss of the liquid circulating in the circulation circuit can be reduced. Furthermore, since the proximal end opening 33H is provided on the proximal end side of the top portion 33B, venous blood flowing from the proximal end side toward the distal end side can be preferably drained. From the above, according to the catheter 30 configured as described above, the burden on the patient's body can be suppressed, the pressure loss of the liquid circulating in the circulation circuit can be reduced, and blood can be drained more efficiently.

[0069] Further, the top portion 33B has a bent shape. According to the catheter 30 configured as described above, when the expansion portion 32 expands, the bent top portion 33B can also contact the blood vessel wall BW (see FIG. 7). In this case, it is possible to prevent the proximal end opening 33H provided on the proximal end side of the top portion 33B from sticking to the blood vessel wall BW, and blood can be preferably drained from the proximal end opening 33H.

[0070] Among the plurality of extension pieces 33, the region on the distal end side of the top 33B (the first curved portion 33A) has a closed shape. According to the catheter 30 configured in this way, when blood is drained, the blood that has entered from the proximal end opening 33H of the second curved portion 33C collides with the first curved portion 33A and moves inside the lumen 30A of the catheter 30, so that blood can be preferably drained. Furthermore, recirculation can be reduced.

[0071] Also, the proximal end opening 33H has an elliptical shape with the axial direction as the major axis. According to the catheter 30 configured in this way, blood can be drained more preferably than with a circular proximal end opening. In addition, compared with a circular proximal end opening, shear stress is less likely to be applied to the blood and red blood cells are less likely to be destroyed, so hemolysis can be suppressed.

[0072] Also, the diameter R1 of the opening 31A at the distal end of the main body portion 31 is configured to be smaller than the outer diameter R2 on the proximal end side of the main body portion 31. According to the catheter 30 configured in this way, the outer diameter of the dilator 50 inserted into the catheter 30 can be made smaller. Therefore, when inserting the catheter 30 and the dilator 50 into the living body in a pre-integrated state, the insertion resistance can be reduced. Furthermore, the followability with respect to the guide wire inserted through the dilator 50 can be improved.

[0073] Among the plurality of extension pieces 33, the region on the distal end side of the top 33B (corresponding to the first curved portion 33A) has a shape that curves inward in the radial direction. According to the catheter 30 configured in this way, the step with the outer periphery of the dilator 50 can be reduced, and the expansion portion 32 can be preferably extended in the axial direction by the dilator 50.

[0074] <Modified Example of Catheter> Next, a modified example of the catheter will be described. In the above-described embodiment, the dilator 50 was applied to the catheter 30 having one lumen 30A. However, as shown in FIGS. 8 to 10, it can also be used for a catheter 60 having a double lumen. Hereinafter, with reference to FIGS. 8 to 10, the configuration of the catheter 60 having a double lumen will be described.

[0075] The catheter 60 is a so-called double-lumen catheter that can perform both blood delivery and blood drainage simultaneously. Therefore, in the extracorporeal circulation device of FIG. 1, in this embodiment, it is not necessary to use two catheters, that is, the venous side catheter (blood drainage catheter) 5 and the arterial side catheter (blood delivery catheter) 6, and the procedure is performed using only the venous side catheter 60.

[0076] In the catheter 60, as shown in FIGS. 8 and 9, the third tube 161 having the first lumen 61 communicating with the blood delivery side hole 163 is arranged in the double tube structure in the lumen of the main body portion 31.

[0077] According to the catheter 60, after the pump of the extracorporeal circulation device is operated to drain blood from the vein (vena cava) of the patient, gas exchange in the blood is performed by the artificial lung to oxygenate the blood, and then this blood is returned to the vein (vena cava) of the patient again, and veno-venous (VV) artificial lung extracorporeal blood circulation can be performed.

[0078] As shown in FIGS. 8 to 10, the catheter 60 has a main body portion 31 extending in the axial direction, an expansion portion 32 provided at the tip of the main body portion 31, and a third tube 161 arranged in the lumen of the main body portion 31. Since the configurations of the main body portion 31 and the expansion portion 32 are the same as those of the catheter 30 of the first embodiment, the description thereof will be omitted.

[0079] As shown in FIG. 9, the catheter 60 has a first lumen 61 that functions as a blood delivery path and a second lumen 62 that functions as a blood drainage path.

[0080] The first lumen 61 is formed in the inner cavity of the third tube 161. The second lumen 62 is formed in the inner cavity of the main body portion 31 and penetrates from the distal end to the proximal end.

[0081] The main body portion 31 is provided with a blood delivery side hole 163 that communicates with the first lumen 61 which is a blood delivery path.

[0082] The shape of the blood delivery side hole 163 is not limited, but as an example, it is configured in an elliptical shape.

[0083] The third tube 161 is inserted into the second lumen 62 from the proximal end side of the main body portion 31 and is connected to the blood delivery side hole 163.

[0084] The blood delivery side hole 163 is disposed in the blood delivery target in the living body, and the blood oxygenated by the artificial lung is sent into the living body through the blood delivery side hole 163.

[0085] The gap portion 33L and the proximal end opening 33H provided in the expansion portion 32 are configured to be disposed in the blood withdrawal target in the living body so as to perform blood withdrawal efficiently.

[0086] In the present embodiment, the catheter 60 is inserted from the internal jugular vein in the neck, and the distal end is placed in the inferior vena cava through the superior vena cava and the right atrium. The blood delivery target is the right atrium, and the blood withdrawal targets are two locations, namely the superior vena cava and the inferior vena cava.

[0087] As shown in FIG. 10, the catheter 60 is inserted and placed in the living body such that the gap portion 33L and the proximal end opening 33H provided in the expansion portion 32 are disposed in the inferior vena cava with the dilator 50 inserted.

[0088] The expansion portion 32 is configured such that the inner diameter is larger than that of the main body portion 31. With the gap portion 33L and the proximal end opening 33H provided in the expansion portion 32 disposed in the blood withdrawal target, the expansion portion 32 is disposed in the inferior vena cava which is a relatively thick blood vessel, and the main body portion 31 is disposed in the superior vena cava which is a relatively thin blood vessel.

[0089] As shown in Fig. 9, the lock connector 136 has a first lock connector 137 communicating with the first lumen 61 and a second lock connector 138 provided in parallel with the first lock connector 137 and communicating with the second lumen 62. The lock connector 136 is a Y-shaped Y-connector in which the first lock connector 137 branches from the second lock connector 138.

[0090] The first lock connector 137 is connected to the proximal end portion of the third tube 161. The second lock connector 138 is coaxially connected to the proximal end portion of the main body portion 31. A blood delivery tube (blood delivery line) is connected to the first lock connector 137, and a blood withdrawal tube (blood withdrawal line) is connected to the second lock connector 138.

[0091] As described above, according to the catheter 60 according to the present embodiment, both the functions of blood withdrawal and blood delivery can be achieved with a single catheter.

[0092] As described above, the catheter according to the present invention has been described through the embodiments and the modified examples. However, the present invention is not limited to only the configurations described in the embodiments and the modified examples, and can be appropriately changed based on the description of the claims.

[0093] For example, in the above-described embodiment, the first curved portion 33A of the expansion piece 33 of the expansion portion 32 has a closed shape. However, as shown in Fig. 11, a tip opening 233H may be provided in the first curved portion 233A of the expansion piece 233 of the expansion portion 232. According to this configuration, blood can also be withdrawn from the tip opening 233H, so that more blood can be withdrawn.

[0094] Also, in the above-described embodiment, the expansion portion 32 is disposed at the tip of the main body portion 31. However, the expansion portion 32 may be disposed at a location moved from the tip toward the proximal end side, as shown in Fig. 12.

[0095] In the above-described embodiment, one extension portion 32 is arranged along the axial direction. However, as shown in FIG. 13, two extension portions 32 may be arranged along the axial direction. Furthermore, three or more extension portions 32 may be arranged.

[0096] In the above-described embodiment, the top portion 33B has a bending point. However, the top portion may be curved so as to protrude outward in the radial direction without having a bending point.

[0097] In the above-described embodiment, the proximal end opening 33H has an elliptical shape with the axial direction as the major axis. However, the configuration of the proximal end opening is not limited as long as it is open.

[0098] In the above-described embodiment, the diameter R1 of the opening 31A at the distal end of the main body portion 31 is configured to be smaller than the outer diameter R2 on the proximal end side of the main body portion 31. However, the diameter R1 of the distal end opening 31A of the main body portion 31 may be equal to the outer diameter R2 on the proximal end side of the main body portion 31, or the diameter R1 of the distal end opening 31A of the main body portion 31 may be configured to be larger than the outer diameter R2 on the proximal end side of the main body portion 31.

Explanation of Reference Numerals

[0099] 30, 60 Catheter (Percutaneous Catheter), 30A Lumen of the catheter, 31 Main body portion, 31A Opening, 32, 232 Extension portion, 33, 233 Extension piece, 33A, 233A First bending portion, 33B Top portion, 33C Second bending portion, 33H Proximal end opening, 33L Gap portion, 233H Distal end opening.

Claims

**Claim 1** A percutaneous catheter having a lumen through which blood flows, comprising: a main body portion extending in the axial direction; an expansion portion provided on the main body portion and configured to be radially expandable and contractible, the expansion portion having a plurality of expansion pieces along the circumferential direction such that a gap portion is formed therebetween when expanded; wherein each of the expansion pieces has a top portion that protrudes outward in the radial direction when expanded; and a proximal opening provided in at least one of the plurality of expansion pieces and provided on the proximal side of the top portion, the percutaneous catheter. **Claim 2** The percutaneous catheter according to claim 1, wherein the top portion has a bent shape. **Claim 3** The percutaneous catheter according to claim 1 or 2, wherein a region of the plurality of expansion pieces on the distal side of the top portion has a closed shape. **Claim 4** The percutaneous catheter according to claim 1 or 2, wherein the expansion portion further has a distal opening provided in at least one of the plurality of expansion pieces and provided on the distal side of the top portion. **Claim 5** The percutaneous catheter according to any one of claims 1 to 4, wherein the proximal opening has an elliptical shape with the axial direction as the major axis. **Claim 6** The percutaneous catheter according to any one of claims 1 to 5, wherein the diameter of the opening at the distal end of the main body portion is configured to be smaller than the outer diameter on the proximal side of the main body portion. **Claim 7** The percutaneous catheter according to any one of claims 1 to 6, wherein a region of the plurality of expansion pieces on the distal side of the top portion has a shape that curves inward in the radial direction.

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