Catheter

Abstract

To provide a catheter capable of sufficiently securing an amount of a cooling medium that comes in contact with a temperature sensor, and accurately measuring the temperature of the cooling medium.SOLUTION: A catheter 100 includes: a double pipe structure part 30 including a first lumen 33 and a second lumen 34 formed between an inner shaft 31 and an outer shaft 32; and a tip structure part 40 formed nearer on a tip side than the double pipe structure part 30, including only the first lumen 33. The fluid injected from a hand side all flows into the first lumen 33 from the second lumen 34. Furthermore, the fluid flowing into the first lumen 33 flows out to the outside of the tip structure part 40 from a side hole 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a catheter. [Background technology]

[0002] Measuring absolute blood flow in blood vessels, such as coronary arteries, is believed to enable the diagnosis and understanding of microvascular diseases throughout tissue. Catheters used to measure blood flow in blood vessels include those that measure absolute blood flow by the thermodilution method, which uses a guidewire equipped with a temperature sensor. Thermodilution blood flow measurement involves injecting cooled or heated saline into the target blood vessel and then calculating the blood flow rate from the subsequent temperature change in the blood flow. Therefore, to accurately calculate blood flow rate, it is necessary to accurately measure the temperatures of the blood, the mixture of blood and cooling medium, and the cooling medium in the vessel.

[0003] However, the temperature sensor attached to the guidewire is very small because the guidewire itself is thin. Therefore, it is susceptible to subtle temperature changes due to the environment, and it may not be possible to accurately measure the temperature of the liquid being measured. For example, when measuring the temperature of a cooling medium, if the sensor is in contact with the catheter lumen, the catheter in contact with the blood may become warm, affecting the sensor and causing it to indicate a temperature higher than the temperature of the cooling medium.

[0004] In addition, since the temperature sensor is positioned circumferentially on the side of the wire, depending on the orientation of the wire, there may be a situation where the amount of cooling medium coming into contact with the temperature sensor is insufficient, making it impossible to accurately measure the temperature of the cooling medium. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2-1230 Summary of the Invention [Problem to be solved by the invention]

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a catheter that can ensure a sufficient amount of cooling medium in contact with a temperature sensor and can accurately measure the temperature of the cooling medium. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention employs the following means.

[0008] The catheter according to the present invention comprises: a double-tube structure portion formed distally of the guidewire port, having a double-tube structure of an inner shaft and an outer shaft, the double-tube structure portion including: a first lumen formed inside the inner shaft and communicating with the guidewire port; and a second lumen formed between the inner shaft and the outer shaft and communicating with a fluid flowing in from the proximal side; a distal end structure portion formed distally of the double-tube structure portion, in which the inner shaft and the outer shaft are integrated by bonding or welding, and which has only the first lumen; Equipped with the double-tube structure has a through-hole penetrating from the second lumen to the first lumen, and the tip structure has a side hole penetrating between the first lumen and the outside of the tip structure, The device is characterized in that the fluid injected from the proximal side flows entirely from the second lumen into the first lumen, and further, the fluid that flows into the first lumen flows out of the tip structure portion through the side hole.

[0009] With the catheter of the present invention, all of the injected fluid passes through the first lumen of the inner shaft and comes into contact with the guide wire inserted inside, allowing a sufficient amount of fluid to come into contact with the temperature sensor provided on the guide wire, enabling accurate temperature measurement.

[0010] In the catheter of the present invention, the inner shaft may have a small-diameter portion with a smaller inner diameter located closer to the proximal end than the tip structure portion. By reducing the diameter of the inner shaft closer to the proximal end than the integrated portion, the possibility of fluid that has flowed into the first lumen flowing out through the guidewire port can be reduced.

[0011] Furthermore, in the catheter of the present invention, the small diameter portion may be formed to have an inner diameter that is 0.02 mm to 0.1 mm larger than the outer diameter of the guidewire to be used. By adopting such a configuration, it is possible to minimize resistance to insertion of the guidewire and reduce the possibility that fluid that has flowed into the first lumen will flow out from the guidewire port.

[0012] Furthermore, in the catheter according to the present invention, the small diameter portion may be provided between 0.5 mm and 10 mm from the distal end structure portion proximal to the catheter body. By adopting such a configuration, it is possible to sufficiently deliver fluid to a temperature sensor provided on the guidewire.

[0013] Furthermore, in the catheter according to the present invention, the tip structure may have an inner diameter of φ0.4 mm to φ1.5 mm. By adopting such a configuration, a sufficient amount of fluid can be flowed to the position where the temperature sensor provided on the guidewire is located.

[0014] Furthermore, in the catheter according to the present invention, the tip structure may be made to have an inner diameter that is 0.15 mm to 0.3 mm larger than the outer diameter of the guidewire to be used. By adopting such a configuration, it is possible to allow a sufficient amount of fluid to flow to the position where the temperature sensor provided on the guidewire is located.

[0015] Furthermore, in the catheter according to the present invention, the distal structure may have a small-diameter shaft portion or distal tip manufactured to have an inner diameter 0.02 mm to 0.1 mm larger than the outer diameter of the guidewire to be used distally of the side hole. By employing such a configuration, the amount of fluid leaking out from the distal end is reduced, and fluid that has flowed into the first lumen from the through-hole of the inner shaft is more likely to flow out to the outside through the side hole.

[0016] Furthermore, in the catheter according to the present invention, the through-hole formed in the double-tube structure may be located 1.0 mm to 5.0 mm proximal to the side hole located closest to the proximal side, thereby ensuring an area for arranging a temperature sensor on the guidewire. [Effects of the Invention]

[0017] According to the catheter of the present invention, it is possible to provide a catheter that enables accurate temperature measurement. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a plan view and a front view of a catheter 100 according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the catheter 100 according to the embodiment of FIG. 1 taken along lines AA, BB, and CC. [Figure 3] FIG. 3 is a DD cross-sectional view of the catheter 100 according to the embodiment of FIG. [Figure 4] FIG. 4 is a cross-sectional view of a catheter 100 according to another embodiment. [Figure 5] FIG. 5 is a cross-sectional view showing an application example of the catheter according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Next, an embodiment of a catheter 100 according to the present invention will be described in detail with reference to the drawings. Fig. 1 is a side view of the catheter 100 according to the embodiment. Fig. 2 is a cross-sectional view of the catheter 100 according to the embodiment. Note that the embodiments and drawings described below exemplify some of the embodiments of the present invention, and are not intended to limit the present invention to these configurations, and can be modified as appropriate within the scope of the gist of the present invention.

[0020] (Embodiment) As shown in FIG. 1, a catheter 100 according to this embodiment is a so-called rapid exchange type catheter 100, and includes a shaft portion 10 and a connector 90 on the proximal side.

[0021] As shown in FIG. 1 or 3, the shaft portion 10 has, from the proximal side, a shaft main body portion 20, a double-tube structure portion 30, and a tip structure portion 40.

[0022] The shaft main body 20 is a tubular member made of a single pipe with a lumen 21 formed inside, and is connected to a connector 90 on the proximal side, and is provided up to the double pipe structure portion 30.

[0023] As shown in FIG. 3 , the double-tube structure 30 is formed as a double tube consisting of an inner shaft 31 and an outer shaft 32. The inner shaft 31 has a first lumen 33 formed on the inner cavity side, and its proximal end 33a is arranged so as to be exposed on the outer periphery of the shaft portion 10, and the opening of the proximal end 33a functions as a guidewire port through which a guidewire 80 is led out. The outer shaft 32 is arranged on the outer periphery of the inner shaft 31, and a second lumen 34 is formed between the inner shaft 31 and the outer shaft 32. The second lumen 34 communicates with the lumen 21 of the shaft main body 20, and fluid flowing in from the proximal connector 90 flows from the lumen 21 into the second lumen 34. The double-tube structure 30 has a through-hole 36 formed therein so that fluid can flow from the second lumen 34 to the first lumen 33. Preferably, the through-hole 36 formed in the double-pipe structure 30 is located 1.0 mm to 5.0 mm closer to the proximal side than a side hole 41 (described later) that is located closest to the proximal side. By locating the through-hole 36 in this position, the temperature of the fluid flowing from the second lumen 34 to the first lumen 33 can be effectively measured by the temperature sensor 81.

[0024] The tip structure 40 is formed on the distal end side of the double-tube structure 30 and has a smaller inner diameter than the double-tube structure 30 so that the inner circumference of the outer shaft 32 fits tightly against the outer circumference of the inner shaft 31. The outer shaft 32 and the inner shaft 31 are bonded or bonded together to form an integrated unit, and the tip structure 40 has only the first lumen 33. The tip structure 40 also has a side hole 41 that penetrates the tip structure 40 to allow fluid that has flowed into the first lumen 33 to flow out from the outer periphery of the tip structure 40. The tip structure 40 does not necessarily require the outer shaft 32 and the inner shaft 31 to be bonded or bonded together over the entire length; as shown in FIG. 4, it is sufficient that the distal end of the second lumen 34 is sealed. The tip structure 40 preferably has an inner diameter α of 0.4 to 1.5 mm, as shown in FIG. 1. The inner diameter α of the tip structure 40 is preferably 0.15 to 0.3 mm larger than the outer diameter of the guidewire 80 to be used. By making the inner diameter to this size, the cooling liquid or the warming liquid can be effectively flowed through the first lumen 33.

[0025] As shown in FIG. 1, the connector 90 is provided on the proximal side of the shaft portion 10, and the inner cavity of the connector 90 and the lumen 21 of the shaft main body 20 are in communication with each other.

[0026] The guide wire 80 used in the catheter 100 is of a type having a temperature sensor 81 near the tip that can measure temperature.

[0027] The catheter 100 thus fabricated is prepared by inserting the guidewire 80 having the temperature sensor 81 into a blood vessel and adjusting the position so that the temperature sensor 81 is positioned near the through-hole 36 formed in the inner shaft 31 of the catheter 100 or at a position distal to the through-hole 36 and proximal to the side hole 41. In this state, a cooling or warming liquid such as saline is gradually injected using a syringe or the like connected to the proximal connector 90. The injected cooling or warming liquid passes through the lumen 21 of the shaft main body 20, then flows into the first lumen 33 via the second lumen 34 and through-hole 36 of the double-tube structure 30. Since all of the cooling or warming liquid flows into the first lumen 33, a sufficient amount of fluid for measurement can come into contact with the temperature sensor 81 provided on the guidewire 80, enabling accurate temperature measurement. Furthermore, the injected cooling or warming liquid mixes with the blood, causing a temperature change. The temperature sensor 81 is then moved to record the change in blood temperature. By analyzing the data on the change in blood temperature, blood flow velocity and cardiac output can be calculated.

[0028] In this embodiment, as shown in Fig. 5, the inner shaft 31 preferably has a small-diameter portion 31a whose inner diameter is smaller proximally than the tip structure 40. This small-diameter portion 31a is preferably made to have an inner diameter that is 0.02 mm to 0.1 mm larger than the outer diameter of the guidewire 80 to be used. Furthermore, the small-diameter portion 31a is preferably made so that the distance β from the tip structure 40 is 0.5 mm to 10 mm proximally. By making the proximal side of the inner shaft 31 smaller in diameter in this way, it is possible to effectively prevent the injected cooling liquid or warming liquid from flowing back toward the proximal side after being injected into the first lumen 33.

[0029] 5, the distal structure 40 may be provided with a small-diameter shaft portion or distal tip 70 having a small-diameter region γ with an inner diameter 0.02 mm to 0.1 mm larger than the outer diameter of the guidewire 80 to be used, located distally of the side hole 41. By providing the small-diameter region γ on the distal side of the distal structure 40, the possibility of the injected cooling liquid or warming liquid leaking out from the distal end after flowing into the first lumen 33 is reduced, and the cooling liquid or warming liquid can be effectively discharged from the side hole 41. This has the effect of allowing the blood and the cooling liquid or warming liquid to be efficiently mixed within a short distance within the blood vessel. [Industrial Applicability]

[0030] As shown in the above-described embodiment, the catheter can be used to measure the blood flow rate in a blood vessel. [Explanation of symbols]

[0031] 10...shaft portion, 20...shaft main body portion, 21...lumen, 30...double tube structure portion, 31...inner shaft, 31a...small diameter portion, 32...outer shaft, 33...first lumen, 33a...proximal end portion, 34...second lumen, 36...through hole, 40...tip structure portion, 41...side hole, 70...tip, 80...guide wire, 81...temperature sensor, 90...connector, 100...catheter

Claims

1. a double-tube structure portion formed distally of the guidewire port, having a double-tube structure of an inner shaft and an outer shaft, the double-tube structure portion including: a first lumen formed inside the inner shaft and communicating with the guidewire port; and a second lumen formed between the inner shaft and the outer shaft and communicating with a fluid flowing in from the proximal side; a distal end structure portion formed distally of the double-tube structure portion, in which the inner shaft and the outer shaft are integrated by bonding or welding, and which has only the first lumen; Equipped with the double-tube structure has a through-hole penetrating from the second lumen to the first lumen, and the tip structure has a side hole penetrating between the first lumen and the outside of the tip structure, A catheter characterized in that the fluid injected from the proximal side flows entirely from the second lumen into the first lumen, and further, the fluid that flows into the first lumen flows out of the tip structure portion through the side hole.

2. 2. The catheter according to claim 1, wherein the inner shaft has a small diameter portion with a smaller inner diameter located closer to the proximal end than the tip structure portion.

3. 3. The catheter according to claim 2, wherein the small diameter portion is fabricated to have an inner diameter that is 0.02 mm to 0.1 mm larger than the outer diameter of the guide wire to be used.

4. 3. The catheter according to claim 2, wherein the small diameter portion is provided between 0.5 mm and 10 mm from the distal end structure portion on the proximal side.

5. 2. The catheter according to claim 1, wherein the tip structure has an inner diameter of 0.4 mm to 1.5 mm.

6. 2. The catheter according to claim 1, wherein the distal end structure portion is fabricated to have an inner diameter that is 0.15 mm to 0.3 mm larger than the outer diameter of the guide wire to be used.

7. The catheter according to claim 1, characterized in that the distal structure portion has a small-diameter shaft portion or distal tip that is manufactured to have an inner diameter that is 0.02 mm to 0.1 mm larger than the outer diameter of the guide wire used distally of the side hole.

8. The catheter according to claim 1, characterized in that the through hole formed in the double-tube structure portion is located 1.0 mm to 5.0 mm proximal to the side hole provided closest to the proximal side.

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