Percutaneous 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 technology]

[0002] Traditionally, percutaneous cardiopulmonary support (PCPS) has been used to provide cardiopulmonary resuscitation, circulatory support, and respiratory support in emergency care. PCPS is a method of temporarily supporting or substituting for cardiopulmonary function 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 removal line, a blood transfer line, etc., and performs gas exchange on the removed blood before transferring it to the blood transfer line.

[0004] In this regard, for example, Patent Document 1 listed below describes a circulation circuit of an extracorporeal circulation device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2007 / 123156 Summary of the Invention [Problem to be solved by the invention]

[0006] When blood is circulated in this circulation circuit, it is circulated by the power of a pump driven by a motor. Therefore, to ensure optimal blood circulation, it is necessary to reduce pressure loss in the blood removal tube (percutaneous catheter) that constitutes the circulation circuit.

[0007] However, if the inner diameter of the blood removal tube is small, the pressure loss increases and the flow rate through the circulation circuit decreases. Therefore, unless the inner diameter of the blood removal tube is large enough, the required amount of blood circulating cannot be obtained.

[0008] On the other hand, increasing the inner diameter of the blood removal tube also increases the outer diameter of the blood removal tube. Therefore, increasing the inner diameter of the blood removal tube inserted into the patient's body increases the degree of invasiveness to the patient's body, and increases the strain on the patient's body.

[0009] Therefore, an object of the present invention is to provide a percutaneous catheter that can reduce the burden on the patient's body and the pressure loss of the liquid circulating in the circulation circuit. [Means for solving the problem]

[0010] A percutaneous catheter that achieves the above object is a percutaneous catheter having a lumen through which blood flows. The percutaneous catheter has a main body portion extending in an axial direction, and an expansion portion provided on the main body portion, configured to be deformable in a radial direction so as to be expandable and contractible, and having a plurality of expansion pieces arranged along a circumferential direction so as to form gaps between the expansion pieces when expanded. Furthermore, when expanded, the expansion pieces have apexes that protrude radially outward and are bent. [Effects of the Invention]

[0011] With the percutaneous catheter configured as described above, when a dilator is inserted into the percutaneous catheter, the expansion pieces expand axially to close the gaps between them, causing the expansion section to contract and reducing the outer diameter of the percutaneous catheter. By inserting the percutaneous catheter into a living body in this state, the burden on the patient's body can be reduced. Furthermore, after the percutaneous catheter is placed in the living body, removing the dilator from the percutaneous catheter causes the expansion section to expand radially. This reduces the pressure loss of the liquid circulating through the circulation circuit. Therefore, with the percutaneous catheter configured as described above, it is possible to provide a percutaneous catheter that reduces the burden on the patient's body and reduces the pressure loss of the liquid circulating through the circulation circuit. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a system diagram showing an example of an extracorporeal circulation device to which a percutaneous catheter according to an embodiment of the present invention is applied. [Figure 2] FIG. 10 is a side view showing the state before the dilator is inserted into the catheter according to the embodiment. [Figure 3] 1 is a side cross-sectional view showing a catheter according to an embodiment of the present invention. [Figure 4] 1 is a schematic diagram showing the vicinity of the tip of a catheter according to an embodiment of the present invention. [Figure 5] FIG. 10 is a side view showing the state after the dilator has been inserted into the catheter according to the present embodiment. [Figure 6] 10 is a schematic diagram showing the vicinity of the tip of the dilator after it has been inserted into the catheter according to this embodiment. FIG. [Figure 7] FIG. 1 is a schematic diagram showing blood removal in a blood vessel. [Figure 8] FIG. 1 is a plan view showing the state before the dilator is inserted into the double lumen catheter. [Figure 9] FIG. 1 is a side cross-sectional view showing a double lumen catheter. [Figure 10]FIG. 10 is a plan view showing the state after the dilator has been inserted into the double lumen catheter. [Figure 11] FIG. 5 is a view corresponding to FIG. 4 of a catheter according to a first modified example. [Figure 12] FIG. 5 is a view corresponding to FIG. 4 of a catheter according to a second modification. [Figure 13] FIG. 10 is a view corresponding to FIG. 4 of a catheter according to a third modification. DETAILED DESCRIPTION OF THE INVENTION

[0013] 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 meaning of terms described in the claims. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0014] FIG. 1 is a system diagram showing an example of an extracorporeal circulation device to which a percutaneous catheter according to an embodiment of the present invention is applied and which is used as percutaneous cardiopulmonary support (PCPS) to temporarily assist and substitute for the functions of the heart and lungs of a patient whose heart is weakened until cardiac function recovers.

[0015] The extracorporeal circulation device 1 can perform a veno-arterial (VA) procedure in which a pump is operated to withdraw blood from a patient's vein (vena cava), an artificial lung is used to exchange gases in the blood to oxygenate the blood, and the blood is then returned to the patient's artery (aorta). This extracorporeal circulation device 1 is a device that assists the heart and lungs. Hereinafter, the procedure of withdrawing blood from a patient, performing a prescribed treatment outside the body, and then returning the blood to the patient's body will be referred to as "extracorporeal circulation."

[0016] 1, the extracorporeal circulation device 1 has a circulation circuit for circulating blood. The circulation circuit has an oxygenator 2, a centrifugal pump 3, a drive motor 4 as a driving means for driving the centrifugal pump 3, a venous catheter (percutaneous catheter for blood removal) 5, an arterial catheter (catheter for blood supply) 6, and a controller 10 as a control unit.

[0017] The venous catheter (blood removal catheter) 5 is inserted through the femoral vein, and the tip of the venous catheter 5 is placed in the right atrium or the transition area from the inferior vena cava to the right atrium via the inferior vena cava. The venous catheter 5 is connected to the centrifugal pump 3 via a blood removal tube (blood removal line) 11. The blood removal tube 11 is a conduit for sending blood.

[0018] The arterial catheter (blood transfer catheter) 6 is inserted from the femoral artery.

[0019] When the drive motor 4 operates the centrifugal pump 3 in response to a command SG from the controller 10, the centrifugal pump 3 can draw blood from the blood removal tube 11, pass the blood through the oxygenator 2, and then return the blood to the patient P via the blood transfer tube (blood transfer line) 12.

[0020] The oxygenator 2 is disposed between the centrifugal pump 3 and the blood feed tube 12. The oxygenator 2 performs gas exchange (addition of oxygen and / or removal of carbon dioxide) with the blood. The oxygenator 2 is, for example, a membrane oxygenator, but a hollow fiber membrane oxygenator is particularly preferred. Oxygen gas is supplied to the oxygenator 2 from an oxygen gas supply unit 13 via a tube 14. The blood feed tube 12 is a conduit connecting the oxygenator 2 and the arterial catheter 6.

[0021] Pipes made of highly transparent, elastically deformable, flexible synthetic resin, such as polyvinyl chloride resin or silicone rubber, can be used for the blood removal tube 11 and the blood transfer tube 12. In the blood removal tube 11, blood, which is liquid, flows in the direction V1, and in the blood transfer tube 12, blood flows in the direction V2.

[0022] 1, an ultrasonic air bubble detection sensor 20 is disposed midway through the blood removal tube 11. A fast clamp 17 is disposed midway through the blood transfer tube 12.

[0023] The ultrasonic air bubble detection sensor 20 detects air bubbles that have been introduced into the circulation circuit during extracorporeal circulation due to erroneous operation of the three-way stopcock 18, tube damage, or the like. When the ultrasonic air bubble detection sensor 20 detects the presence of air bubbles in the blood being sent into the blood removal tube 11, the ultrasonic air bubble detection sensor 20 sends a detection signal to the controller 10. Based on this detection signal, the controller 10 issues an alarm and either reduces the rotation speed of the centrifugal pump 3 or stops the centrifugal pump 3. Furthermore, the controller 10 commands the fast clamp 17 to immediately close the blood transfer tube 12 with the fast clamp 17, thereby preventing air bubbles from being sent into the body of the patient P. The controller 10 controls the operation of the extracorporeal circulation device 1 to prevent air bubbles from entering the body of the patient P.

[0024] A pressure sensor is provided in the tube 11 (12, 19) of the circulation circuit of the extracorporeal circulation apparatus 1. The pressure sensor can be attached to, for example, any one or all of the following: attachment position A1 of the blood removal tube 11, attachment position A2 of the blood transfer tube 12 of the circulation circuit, or attachment position A3 of the connection tube 19 connecting the centrifugal pump 3 and the oxygenator 2. This allows the pressure sensor to measure the pressure inside the tube 11 (12, 19) when extracorporeal circulation is being performed for the patient P by the extracorporeal circulation apparatus 1. Note that the attachment positions of the pressure sensors are not limited to the above-mentioned attachment positions A1, A2, and A3, and any number of pressure sensors can be attached to any positions of the circulation circuit.

[0025] Next, the configuration of a percutaneous catheter (hereinafter referred to as "catheter") 30 through which the dilator 50 is inserted will be described with reference to Figures 2 to 7. Figures 2 to 7 are diagrams used to explain the configuration of the catheter 30. This catheter 30 is used as the venous catheter (blood removal catheter) 5 in Figure 1.

[0026] As shown in Figure 2, the catheter 30 has a main body 31 extending in the axial direction, an expansion section 32 provided at the tip of the main body 31, a clamping tube 34 arranged on the base end side of the main body 31, a catheter connector 35 connecting the main body 31 and the clamping tube 34, and a lock connector 36.

[0027] In this specification, the side inserted into the living body is referred to as the "distal end" or "distal side," and the side operated by the surgeon is referred to as the "proximal end" or "proximal side." The distal end refers to a certain range including the distal end (the most distal end) and its surroundings, and the proximal end refers to a certain range including the proximal end (the most proximal end) and its surroundings.

[0028] As shown in Fig. 3, the catheter 30 has a lumen 30A that penetrates from the tip to the base end. The gap 33L and base end opening 33H (see Fig. 4) provided in the expansion section 32 are configured to be positioned at the blood removal target in the living body to enable efficient blood removal.

[0029] When inserting the catheter 30 into a living body, a dilator 50 shown in Figure 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 where they are previously integrated.

[0030] Each component of the catheter 30 will be described below.

[0031] As shown in Figures 2 and 3, the main body 31 is configured to extend in the axial direction. As shown in Figure 4, the diameter R1 of the opening 31A at the tip of the main body 31 is configured to be smaller than the outer diameter R2 of the base end of the main body 31. This configuration allows the outer diameter of the dilator 50 inserted into the catheter 30 to be reduced. Therefore, when the catheter 30 and the dilator 50 are inserted into a living body while they are previously integrated, insertion resistance can be reduced. Furthermore, the dilator 50 can be improved in terms of followability with respect to a guidewire inserted therethrough.

[0032] As shown in Figures 2 and 3, the expansion section 32 is provided at the tip of the main body section 31. As shown in Figures 2 to 6, the expansion section 32 is configured to be capable of expanding and contracting in the radial direction. As shown in Figure 4, the expansion section 32 has a plurality of expansion pieces 33 provided along the circumferential direction so that gaps 33L are formed between them when expanded.

[0033] In this embodiment, ten expansion pieces 33 are provided along the circumferential direction, but the number is not limited to ten. Each expansion piece 33 is provided along the axial direction in a bent state when expanded. Gaps 33L are formed between the ten expansion pieces 33. The gaps 33L function as blood removal holes.

[0034] As shown in FIG. 4, the extension piece 33 has, in order from the distal end side, a first curved portion 33A, a top portion 33B, and a second curved portion 33C.

[0035] 4, the first curved portion 33A is curved so as to convex radially inward. With this configuration, the step with the outer periphery of the dilator 50 can be reduced, and the dilator 50 can suitably extend the expansion portion 32 in the axial direction.

[0036] The first curved portion 33A has a closed shape as shown in Fig. 4. With this configuration, as will be described later, during blood removal, blood that has entered through the proximal opening 33H of the second curved portion 33C collides with the first curved portion 33A and moves into the lumen 30A of the catheter 30, thereby enabling preferable blood removal.

[0037] Furthermore, the closed shape of the first curved portion 33A can reduce recirculation. Here, recirculation refers to the phenomenon in which blood is drawn from a patient's vein (vena cava), oxygenated through gas exchange in the blood using an artificial lung, and then returned to the patient's artery (aorta), causing the oxygenated blood to be drawn again. Recirculation generally occurs when blood flows from the distal end to the proximal end of the catheter 30 (see the right-pointing arrow in FIG. 7 ). However, in the catheter 30 according to this embodiment, the closed shape of the first curved portion 33A can reduce the amount of blood flowing from the distal end to the proximal end of the catheter 30 that moves into the lumen 30A of the catheter 30, thereby reducing recirculation.

[0038] The apex 33B protrudes radially outward when the expansion section 32 is expanded. The apex 33B has a bent shape as shown in FIG. 4. According to this configuration, when the expansion section 32 is expanded, the bent apex 33B comes into contact with the blood vessel wall BW (see the left-pointing arrow in FIG. 7). This prevents the base-end opening 33H provided on the base end side of the apex 33B from sticking to the blood vessel wall, allowing blood to be removed preferably from the base-end opening 33H.

[0039] The second curved portion 33C is configured to be curved so as to convex radially inward, similar to the first curved portion 33A.

[0040] As shown in Figure 4, a base-end opening 33H is formed in the second curved section 33C. The base-end opening 33H functions as a blood removal hole. Generally, within a blood vessel, the venous flow is greater from the base end side to the tip end side of the catheter 30 (see Figure 7). Therefore, when the expansion section 32 is expanded, the base-end opening 33H opens so as to face the base end side, and blood can be removed preferably from the base-end opening 33H.

[0041] The proximal opening 33H has an elliptical shape with the axial direction as the major axis. This configuration allows for more effective blood removal than a circular proximal opening. Furthermore, compared to a circular proximal opening, the proximal opening 33H applies less shear stress to the blood, making it less likely for red blood cells to be destroyed, thereby suppressing hemolysis.

[0042] In this embodiment, the target for blood removal is the inferior vena cava. The catheter 30 is inserted and left in the living body so that the gap 33L and the proximal opening 33H of the expansion section 32 are positioned in the inferior vena cava.

[0043] With the gap portion 33L and the base end opening 33H of the expansion portion 32 positioned in the blood removal target, the expansion portion 32 is placed in the inferior vena cava, which is a relatively large blood vessel, and the main body portion 31 is placed in the femoral vein, which is a relatively small blood vessel.

[0044] Furthermore, when the dilator 50 is inserted into the lumen 30A of the catheter 30, the expansion section 32 is stretched in the axial direction, reducing its outer and inner diameters, as shown in Figures 5 and 6. At this time, the outer diameter of the expansion section 32 becomes approximately the same as the outer diameter of the main body section 31. Because the catheter 30 is inserted into the living body with the expansion section 32 stretched in the axial direction and its outer and inner diameters reduced, the catheter 30 can be inserted minimally invasively.

[0045] Furthermore, after the catheter 30 is placed in the living body, when the dilator 50 is removed from the lumen 30A of the catheter 30, the expansion section 32 expands radially outward, increasing its inner diameter. Here, the expansion section 32 is placed in the inferior vena cava, which is a relatively thick blood vessel.

[0046] Here, the pressure loss inside the expansion section 32 is calculated as the total length of the expansion section 32 multiplied by the (average) cross-sectional area of ​​the passage. That is, by increasing the inner diameter of the expansion section 32, the pressure loss inside the expansion section 32 is reduced. When the pressure loss inside the expansion section 32 is reduced, the flow rate of blood flowing through the circulation circuit increases without increasing the rotation speed of the centrifugal pump. For this reason, in order to obtain a sufficient amount of blood circulation, it is necessary to increase the inner diameter of the expansion section 32.

[0047] The inner diameter of the main body portion 31 is, for example, 2.0 to 10.0 mm. The inner diameter of the expansion portion 32 when expanded is, for example, 2.5 to 40.0 mm.

[0048] The material for forming the main body 31 and the extension portion 32 is not particularly limited, but polyethylene, polypropylene, PVC, pelprene, nylon, polyurethane, PEEK, polyimide, and fluorine-based tubes can be used.

[0049] 2 and 5, the clamping tube 34 is provided on the proximal end side of the main body portion 31. A lumen through which the dilator 50 can be inserted is provided inside the clamping tube 34. The clamping tube 34 can be formed using the same material as the main body portion 31.

[0050] 2 and 5, the catheter connector 35 connects the main body 31 and the clamp tube 34. Inside the catheter connector 35, a lumen is provided through which the dilator 50 can be inserted.

[0051] 2 and 5, the lock connector 36 is connected to the proximal end side of the clamp tube 34. A lumen through which the dilator 50 can be inserted is provided inside the lock connector 36. A male screw portion 36A having a screw thread is provided on the outer surface of the proximal end side of the lock connector 36.

[0052] Next, a description will be given of the configuration of the dilator 50. Note that the configuration of the dilator 50 is not limited to the following configuration.

[0053] As shown in FIG. 2, the dilator 50 has a dilator tube 51 extending in the axial direction, a dilator hub 52 to which the base end of the dilator tube 51 is fixed, and a screw ring 53 provided at the tip of the dilator hub 52.

[0054] The dilator tube 51 is a long body that extends in the axial direction and has relatively high rigidity. The total axial length of the dilator tube 51 is longer than the total axial length of the catheter 30. The dilator tube 51 is provided with a guidewire lumen 54 through which a guidewire (not shown) can be inserted. The dilator tube 51 is guided by the guidewire and inserted into the living body together with the catheter 30. After the catheter 30 has been placed 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.

[0055] 2, the tip of the dilator tube 51 has a tapered surface 50a that abuts against the opening 31A at the tip of the main body 31. The dilator tube 51 has a relatively high rigidity and is strong enough to transmit a pushing force toward the tip side to the main body 31 when operated by hand.

[0056] The screw ring 53 has a female thread portion (not shown) with a screw groove formed on the inner surface of the lumen. The dilator 50 can be attached to the catheter 30 by screwing the female thread portion of the screw ring 53 into the male thread portion 36A of the lock connector 36.

[0057] <How to use the dilator> Next, a method of using the above-mentioned catheter 30 will be described with reference to Figures 2 to 7. Figure 2 shows the state before the dilator tube 51 of the dilator 50 is inserted into the lumen 30A of the catheter 30, and Figure 5 shows the state after the dilator tube 51 has been inserted into the lumen 30A of the catheter 30.

[0058] 5, the dilator tube 51 of the dilator 50 is inserted into the lumen 30A of the catheter 30. The dilator tube 51 passes through the main body portion 31 and the expansion portion 32 in that order, and the tapered surface 50a of the dilator tube 51 abuts against the opening 31A at the tip of the main body portion 31.

[0059] 2, the total axial length of the dilator tube 51 is longer than the total axial length of the catheter 30 before the expansion section 32 is expanded. Therefore, by inserting the dilator 50 into the catheter 30, the catheter 30 receives a force that expands it in the axial direction, causing the expansion section 32 to expand in the axial direction and suitably contract radially inward.

[0060] Thereafter, the female thread portion of the screw ring 53 is screwed into the male thread portion 36A provided on the lock connector 36 of the catheter 30, thereby attaching the dilator 50 to the catheter 30.

[0061] Next, the catheter 30 with the dilator 50 inserted therethrough is inserted along a guide wire (not shown) that has been inserted into the target site in advance inside the living body. At this time, because the dilator 50 is inserted through the catheter 30, the outer diameter of the expansion section 32 is approximately the same as the outer diameter of the main body section 31, allowing the catheter 30 to be inserted into the living body in a minimally invasive manner, thereby reducing the burden on the patient's body.

[0062] Furthermore, catheter 30 is inserted into the living body and left in place until gap 33L and base end opening 33H of expansion section 32 are positioned at or near the right atrium. With gap 33L and base end opening 33H positioned at the target for blood removal, expansion section 32 is positioned in the inferior vena cava, which is a relatively large blood vessel, and main body section 31 is positioned in the femoral vein, which is a relatively small blood vessel.

[0063] Next, the dilator 50 and guide wire are removed from the catheter 30. At this time, the dilator 50 and guide wire are first removed to the clamping tube 34 of the catheter 30 and clamped with forceps (not shown), and then completely removed from the catheter 30. By removing the dilator 50 from the lumen of the catheter 30, the catheter 30 is released from the axially stretching force that the catheter 30 was receiving from the dilator 50. As a result, the expansion section 32 contracts in the axial direction, and the inner diameter of the expansion section 32 increases. This reduces pressure loss within the expansion section 32 and ensures the required flow rate of liquid.

[0064] Next, the lock connector 36 of the catheter 30 is connected to the blood removal tube 11 of the extracorporeal circulation device shown in Figure 1. After confirming that the connection of the blood supply catheter is complete, the clamp on the clamping tube 34 is released to start extracorporeal circulation.

[0065] 7, blood is removed through the gap 33L and the base-end opening 33H of the expansion section 32. According to the catheter 30 of this embodiment, the first curved section 33A has a closed shape, so that recirculation can be suppressed.

[0066] After the extracorporeal circulation is completed, the catheter 30 is removed from the blood vessel, and the insertion site is surgically repaired for hemostasis, if necessary.

[0067] As described above, the catheter 30 according to this embodiment includes a lumen 30A through which blood flows. The catheter 30 includes a main body 31 extending in the axial direction and an expansion section 32 attached to the main body 31, configured to be radially expandable and contractible, and including multiple expansion pieces 33 arranged along the circumferential direction so as to form gaps 33L between the expansion pieces 33 upon expansion. Each expansion piece 33 has a top portion 33B that protrudes radially outward upon expansion and a proximal opening 33H located closer to the proximal end than the top portion 33B. When a dilator 50 is inserted into the catheter 30 configured in this manner, the expansion pieces 33 expand in the axial direction to close the gaps 33L between the expansion pieces 33, thereby contracting the expansion section 32 and reducing the outer diameter of the catheter 30. Inserting the catheter 30 into a living body in this state reduces the strain on the patient's body. Furthermore, when the dilator 50 is removed from the catheter 30 after the catheter 30 has been placed in the living body, the expansion section 32 expands radially. This reduces the pressure loss of the fluid circulating through the circulation circuit. Furthermore, since the base-end opening 33H is located closer to the base end than the apex 33B, blood can be removed effectively from the venous flow that flows from the base end toward the tip end. As described above, the catheter 30 configured as described above reduces the burden on the patient's body, reduces the pressure loss of the fluid circulating through the circulation circuit, and enables more efficient blood removal.

[0068] Furthermore, the apex portion 33B has a curved shape. According to the catheter 30 configured in this manner, when the expansion section 32 is expanded, the curved apex portion 33B can also come into contact with the blood vessel wall BW (see FIG. 7). In this case, the base-end opening 33H provided on the base end side of the apex portion 33B can be prevented from sticking to the blood vessel wall BW, and blood can be preferably removed from the base-end opening 33H.

[0069] Furthermore, the region (first curved portion 33A) of the multiple expansion pieces 33 that is distal to the apex 33B has a closed shape. With the catheter 30 configured in this manner, during blood removal, blood that has entered through the proximal opening 33H of the second curved portion 33C collides with the first curved portion 33A and moves into the lumen 30A of the catheter 30, thereby enabling favorable blood removal. Furthermore, recirculation can be reduced.

[0070] The proximal opening 33H has an elliptical shape with the axial direction as the major axis. The catheter 30 configured in this manner allows for more effective blood removal than a circular proximal opening. Furthermore, the proximal opening 33H is less susceptible to shear stress being applied to the blood, which reduces the likelihood of red blood cell destruction, compared to a circular proximal opening, thereby suppressing hemolysis.

[0071] Furthermore, the diameter R1 of the opening 31A at the tip of the main body 31 is configured to be smaller than the outer diameter R2 of the base end of the main body 31. With a catheter 30 configured in this manner, the outer diameter of the dilator 50 inserted into the catheter 30 can be reduced. Therefore, when the catheter 30 and the dilator 50 are inserted into a living body while they are previously integrated, insertion resistance can be reduced. Furthermore, the followability of the dilator 50 to the guidewire inserted inside can be improved.

[0072] Furthermore, among the multiple expansion pieces 33, the region (corresponding to the first curved portion 33A) that is distal from the apex 33B has a shape that curves radially inward. With the catheter 30 configured in this manner, the step with the outer periphery of the dilator 50 can be reduced, and the dilator 50 can suitably extend the expansion portion 32 in the axial direction.

[0073] <Modified Catheter> Next, modified examples of the catheter will be described. In the above-described embodiment, the dilator 50 is applied to the catheter 30 having one lumen 30A. However, it can also be used for a catheter 60 having double lumens as shown in Figures 8 to 10. Hereinafter, the configuration of the catheter 60 having double lumens will be described with reference to Figures 8 to 10.

[0074] The catheter 60 is a so-called double lumen catheter, which is capable of both blood feeding and blood removal at the same time. Therefore, in this embodiment, the extracorporeal circulation device of Fig. 1 does not use two catheters, the venous catheter (blood removal catheter) 5 and the arterial catheter (blood feed catheter) 6, but instead uses only the venous catheter 60 for the procedure.

[0075] As shown in FIGS. 8 and 9, the catheter 60 has a double-tube structure in which a third tube 161 having a first lumen 61 communicating with a blood feed side hole 163 is disposed in the inner cavity of the main body portion 31.

[0076] The catheter 60 enables veno-venous (VV) extracorporeal blood circulation using an artificial lung, in which blood is drawn from the patient's vein (vena cava) by operating the pump of the extracorporeal circulation device, gas exchange is carried out in the blood using an artificial lung to oxygenate the blood, and the blood is then returned to the patient's vein (vena cava).

[0077] 8 to 10, the catheter 60 has a main body section 31 extending in the axial direction, an expansion section 32 provided at the tip of the main body section 31, and a third tube 161 disposed in the lumen of the main body section 31. The configurations of the main body section 31 and the expansion section 32 are the same as those of the catheter 30 of the first embodiment, and therefore description thereof will be omitted.

[0078] As shown in FIG. 9, the catheter 60 has a first lumen 61 that functions as a blood feed channel and a second lumen 62 that functions as a blood removal channel.

[0079] 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 passes through from the distal end to the proximal end.

[0080] The main body 31 is provided with a blood feed side hole 163 that communicates with the first lumen 61, which is a blood feed path.

[0081] The shape of the blood feed side hole 163 is not limited, but as an example, it is configured to be elliptical.

[0082] The third tube 161 is inserted into the second lumen 62 from the base end side of the main body portion 31 and is connected to the blood feed side hole 163 .

[0083] The blood feed side hole 163 is placed at a blood feed target inside the living body, and blood that has been oxygenated by the artificial lung is fed into the living body via the blood feed side hole 163.

[0084] The gap 33L and the proximal opening 33H of the expansion section 32 are configured to be placed at the blood removal target in the living body to enable efficient blood removal.

[0085] In this embodiment, the catheter 60 is inserted through the internal jugular vein in the neck, passes through the superior vena cava and the right atrium, and its tip is placed in the inferior vena cava. The target for blood supply is the right atrium, and the targets for blood removal are the superior vena cava and the inferior vena cava.

[0086] As shown in FIG. 10, with the dilator 50 inserted, the catheter 60 is inserted and placed in the living body so that the gap 33L and the base end opening 33H of the expansion section 32 are positioned in the inferior vena cava.

[0087] The expansion section 32 is configured to have an inner diameter larger than that of the main body section 31. With the gap section 33L and the base end opening section 33H of the expansion section 32 placed in the blood removal target, the expansion section 32 is placed in the inferior vena cava, which is a relatively thick blood vessel, and the main body section 31 is placed in the superior vena cava, which is a relatively thin blood vessel.

[0088] 9, lock connector 136 has a first lock connector 137 that communicates with first lumen 61, and a second lock connector 138 that is provided in parallel to first lock connector 137 and communicates with second lumen 62. Lock connector 136 is a Y-shaped Y connector formed by first lock connector 137 branching off from second lock connector 138.

[0089] The first lock connector 137 is connected to the base end of the third tube 161. The second lock connector 138 is coaxially connected to the base end of the main body 31. A blood transfer tube (blood transfer line) is connected to the first lock connector 137, and a blood removal tube (blood removal line) is connected to the second lock connector 138.

[0090] As described above, the catheter 60 according to this embodiment can perform both the functions of blood removal and blood transfer with a single catheter.

[0091] The catheter according to the present invention has been described above through embodiments and modifications thereof, but the present invention is not limited to the configurations described in the embodiments and modifications thereof, and can be modified as appropriate based on the claims.

[0092] For example, in the above-described embodiment, the first curved portion 33A of the expansion piece 33 of the expansion section 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 section 232. With this configuration, blood can also be removed from the tip opening 233H, allowing a larger amount of blood to be removed.

[0093] In the above-described embodiment, the extension portion 32 is disposed at the tip of the main body portion 31. However, the extension portion 32 may be disposed at a position moved from the tip toward the base end, as shown in FIG.

[0094] In the above-described embodiment, one extension portion 32 is arranged along the axial direction. However, two extension portions 32 may be arranged along the axial direction as shown in Fig. 13. Furthermore, three or more extension portions 32 may be arranged.

[0095] In the above-described embodiment, the apex 33B has a bending point. However, the apex may be configured to be curved so as to be convex outward in the radial direction without having a bending point.

[0096] Furthermore, in the above-described embodiment, the proximal end opening 33H has an elliptical shape with the axial direction being the major axis, but the configuration of the proximal end opening is not limited as long as it is open.

[0097] Furthermore, the diameter R1 of the opening 31A at the tip of the main body 31 is configured to be smaller than the outer diameter R2 on the base end side of the main body 31. However, the diameter R1 of the tip opening 31A of the main body 31 may be configured to be equal to the outer diameter R2 on the base end side of the main body 31, or the diameter R1 of the tip opening 31A of the main body 31 may be configured to be larger than the outer diameter R2 on the base end side of the main body 31. [Explanation of symbols]

[0098] 30, 60 catheters (percutaneous catheters), 30A catheter lumen, 31 main body, 31A opening, 32, 232 extensions, 33, 233 extension pieces, 33A, 233A first curved section, 33B top, 33C second curved section, 33H proximal opening, 33L gap, 233H Tip opening.

Claims

1. A percutaneous catheter having a lumen through which blood flows, a main body portion extending in an axial direction; an expansion section provided on the main body section, configured to be deformable in a radial direction and expand and contract, and having a plurality of expansion pieces along a circumferential direction so that gaps are formed between the expansion pieces when expanded; The extension piece is A percutaneous catheter having a top portion that protrudes radially outward and has a curved shape when expanded.

2. The main body has an opening at a tip, The lumen extends from the distal end to the proximal end, The percutaneous catheter according to claim 1 , wherein the gap and the opening communicate with the lumen.

3. A percutaneous catheter having a lumen through which blood flows, a main body portion extending in an axial direction; an expansion section provided on the main body section, configured to be deformable in a radial direction and expand and contract, and having a plurality of expansion pieces along a circumferential direction so that gaps are formed between the expansion pieces when expanded; The extension piece is an apex portion that protrudes outward in the radial direction when expanded; a first curved portion disposed distally of the apex; a second curved portion disposed on the base end side relative to the apex portion, A percutaneous catheter, wherein at least one of the first curved portion and the second curved portion has a shape that curves radially inward.

4. The percutaneous catheter of claim 3 , wherein the apex comprises a curved shape.

5. The percutaneous catheter according to any one of claims 1 to 4, wherein the region of the plurality of expansion pieces that is distal to the apex has a closed shape.

6. The percutaneous catheter according to any one of claims 1 to 5, wherein the expansion section is provided in at least one of the plurality of expansion pieces, and further has a tip opening provided on the tip side of the apex, and a base opening provided on the base side of the apex.

7. The percutaneous catheter according to any one of claims 1 to 6, wherein the proximal end opening has an elliptical shape with the axial direction as its major axis.

8. The percutaneous catheter according to any one of claims 1 to 7, wherein the diameter of the opening at the tip of the main body is smaller than the outer diameter of the base end of the main body.

9. The percutaneous catheter according to claim 1 or 2, wherein a region of the plurality of expansion pieces that is distal from the apex has a shape that curves inward in the radial direction.

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