Intra-aortic balloon catheter

Abstract

This invention provides an intra-aortic balloon catheter that can further enhance the effectiveness of IABP (Intra-Aortic Balloon Padding). [Solution] The intra-aortic balloon catheter 1 used in IABP according to the present invention comprises a catheter tube 2 and a balloon portion 3 attached to the distal end of the catheter tube 2, which can be expanded and contracted by supplying and discharging fluid into and out of the catheter, characterized in that the balloon diameter D when the balloon portion 3 is expanded is greater than D:L = 1:9 with respect to the balloon length L.

Description

Technical Field

[0001] The present invention relates to an intra-aortic balloon catheter used for IABP (Intra-Aortic Balloon Pumping).

Background Art

[0002] In IABP, a balloon catheter is inserted into the aorta and the balloon part is placed in the descending thoracic aorta, and the balloon part is expanded and contracted in accordance with the heartbeat to assist cardiac function.

[0003] In IABP, generally, an intra-aortic balloon catheter having a size suitable for the patient's physique is used. For example, in Patent Document 1 below, the length (l) is 15 to 25 cm, and the cross-sectional area (a) based on the outer diameter is 1.4 to 2.0 cm 2 and an intra-aortic balloon pumping balloon catheter having a cylindrical balloon part within the range of l = 15a·(4.5 ± 2) is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] IABP involves risks such as blood flow obstruction due to occlusion of the balloon part, aortic deviation, and balloon rupture. Therefore, currently, in order to assist cardiac function while ensuring safety, an intra-aortic balloon catheter with a balloon diameter smaller than the aortic diameter is used, but the development of an intra-aortic balloon catheter that further improves the effect of IABP is desired.

[0006] This invention has been made in view of the above-mentioned problems, and aims to provide an intra-aortic balloon catheter that can further improve the effectiveness of IABP. [Means for solving the problem]

[0007] After extensive research, the inventors have found that the operation of IABP likely affects the side branches (such as coronary arteries) located near the balloon portion implanted in the descending aorta, thereby improving blood flow and hemodynamics.

[0008] Furthermore, the inventors have experimentally confirmed that while conventional intra-aortic balloon catheters have a balloon diameter smaller than the aortic diameter, increasing the balloon diameter and balloon volume enhances the effectiveness of IABP, and that even if the balloon expands beyond the aortic diameter and occludes the aorta, it does not obstruct blood flow. Based on these findings, the inventors have completed the present invention.

[0009] In other words, to achieve the above objective, the present invention provides an intra-aortic balloon catheter for use in IABP, comprising a catheter tube and a balloon portion attached to the distal end of the catheter tube, which is expandable and deflated by supplying and discharging fluid into and out of the catheter, characterized in that the balloon diameter D when the balloon portion is expanded is greater than D:L = 1:9 with respect to the balloon length L.

[0010] According to the above configuration, by considering the ratio of balloon diameter to balloon length during balloon expansion and making the balloon diameter larger than a certain ratio to the balloon length, the effect of IABP can be further improved, and blood flow to the side branches can be improved more effectively. This makes it possible to appropriately support the patient's cardiac function and improve blood flow and hemodynamics. [Brief explanation of the drawing]

[0011] [Figure 1]This is a schematic cross-sectional view showing an example of an intra-aortic balloon catheter in an embodiment of the present invention. [Figure 2] Figure 1 is a side view of the balloon portion of the intra-aortic balloon catheter. [Figure 3] This is a cross-sectional view along line AA shown in Figure 2. [Figure 4] This figure schematically shows the measurement sites for circulatory system parameters in an embodiment of the present invention. [Figure 5] This graph shows an example of the measurement results of common carotid artery blood flow (CCA-F) in an embodiment of the present invention. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. In this specification, the proximal side (outside the patient's body) of the user using the intra-aortic balloon catheter will be referred to as the proximal side, and the distal side (inside the patient's body) will be referred to as the distal side. The drawings referenced in this specification are not necessarily to an accurate scale to the actual dimensions, and some parts have been exaggerated or simplified in order to schematically illustrate the configuration of the present invention.

[0013] Figure 1 is a schematic cross-sectional view showing an example of an intra-aortic balloon catheter 1 in this embodiment.

[0014] As shown in Figure 1, the intra-aortic balloon catheter 1 in this embodiment has a catheter tube 2, a balloon portion 3, and a branch portion 4. The intra-aortic balloon catheter 1 is inserted into an artery and used in IABP to assist cardiac function by expanding and contracting the balloon portion 3, which is placed in the descending aorta, in accordance with the heartbeat.

[0015] The catheter tube 2 has a double-tube structure consisting of an inner tube 21 and an outer tube 22.

[0016] Inside the inner tube 21, a first lumen 21L is formed. The first lumen 21L is a lumen formed axially inside the inner tube 21 and is open at the distal end and proximal end of the inner tube 21.

[0017] Inside the outer tube 22, a second lumen 22L is formed. The second lumen 22L is a gap formed between the outer peripheral surface of the inner tube 21 inserted into the lumen of the outer tube 22 and the inner peripheral surface of the outer tube 22, and is open at the distal end and proximal end of the outer tube 22.

[0018] Also, the outer peripheral surface of the inner tube 21 inserted into the outer tube 22 is fixed to the inner peripheral surface of the outer tube 22 with an adhesive. By fixing the inner tube 21 and the outer tube 22 in this way, the flow path resistance of the fluid in the second lumen 22L can be reduced, and the responsiveness of the balloon portion 3 can be improved. The adhesive used for fixing is not particularly limited, and adhesives such as cyanoacrylate adhesives and epoxy adhesives can be used, and it is particularly preferable to use a cyanoacrylate adhesive.

[0019] The inner tube 21 is inserted into the second lumen 22L formed inside the outer tube 22, and the first lumen 21L and the second lumen 22L are isolated from each other. The first lumen 21L is used as an insertion path for the guide wire. The second lumen 22L is used as a flow path for the fluid introduced into the balloon portion 3. The fluid introduced into the balloon portion 3 is not particularly limited, but by using a helium gas or the like with low viscosity and mass, the balloon portion 3 can be quickly expanded and contracted according to the drive of the pump device.

[0020] The inner tube 21 protrudes distally from the opening 22a at the distal end of the outer tube 22. At the distal end of the inner tube 21, a cylindrical tip tip 5 having an axially through hole 51 formed therein is attached by means such as heat fusion or adhesion. The first lumen 21L formed inside the inner tube 21 communicates with the outside (inside the artery) through the through hole 51 of the tip tip 5.

[0021] The inner diameter of the inner tube 21 is not particularly limited as long as the guide wire can be inserted therethrough. For example, it is 0.15 to 1.5 mm, preferably 0.3 to 1 mm. Also, the outer diameter of the inner tube 21 is not particularly limited, for example, it is 0.5 to 1.5 mm, and preferably it is 30 to 60% of the inner diameter of the outer tube 22. The outer diameter of the outer tube 22 is not particularly limited either, and it may be any size that allows the balloon portion 3 to be inserted from the femoral artery into the descending aorta according to a conventional method.

[0022] The materials of the inner tube 21 and the outer tube 22 are not particularly limited either. The inner tube 21 can be constituted by, for example, a synthetic resin tube such as polyurethane, polyvinyl chloride, polyethylene, polyamide, polyetheretherketone (PEEK), or a nickel-titanium alloy thin tube, a stainless steel thin tube, etc. When the inner tube 21 is constituted by a synthetic resin tube, a stainless steel wire or the like may be embedded therein. Also, the outer tube 22 can be constituted by, for example, a synthetic resin such as polyurethane, polyvinyl chloride, polyethylene terephthalate, polyamide, etc., and a stainless steel wire or the like may be embedded therein.

[0023] The distal end of the tip 5 is formed in a hemispherical shape. The axial length of the tip 5 is not particularly limited, for example, it is from 5 to 25 mm. The inner diameter (the diameter of the through-hole 51) of the tip 5 may be about the same as the inner diameter of the inner tube 21, and the outer diameter of the tip 5 may be about the same as the outer diameter of the outer tube 22. The material of the tip 5 is not particularly limited, but it is preferably constituted by a relatively flexible material, and soft polyvinyl chloride, silicone, polyurethane, polyamide, various elastomers, natural rubber, etc. can be used. From the viewpoint of antithrombogenicity, it is preferable to use polyurethane.

[0024] The balloon portion 3 is attached to the distal end of the catheter tube 2. The balloon portion 3 is composed of a thin film with a thickness of approximately 50 to 150 μm. The material of the thin film constituting the balloon portion 3 is not particularly limited, but it is preferably a material with excellent bending fatigue resistance, such as polyurethane, silicone, soft polyethylene, soft polyamide, soft polyester, or polyamide elastomer, and it is preferable to use polyurethane, which has high thrombus formation suppression ability and abrasion resistance. The method for molding the balloon portion 3 is not particularly limited, but dipping molding or blow molding is preferably used.

[0025] The tubular distal end 30a of the balloon section 3 is attached to the outer surface of the tip 5 by means of heat fusion or adhesive. The tubular proximal end 30b of the balloon section 3 is attached to the outer surface of the distal end of the outer tube 22 by heat fusion or adhesive. The tubular distal end 30a of the balloon section 3 may be attached to an area that spans both the tip 5 and the inner tube 21. In addition, a contrast marker 2M made of an X-ray opaque metal ring or the like may be provided near the balloon section 3 so that its position can be confirmed under X-ray fluoroscopy. In Figure 1, the contrast marker 2M is provided at the distal end of the outer tube 22.

[0026] The cylindrical distal end 30a of the balloon section 3 is attached tightly to the outer surface of the tip 5 to prevent the fluid introduced into the balloon section 3 from leaking to the outside. The cylindrical proximal end 30b of the balloon section 3 is attached tightly to the outer surface of the outer tube 22 to prevent the fluid introduced into the balloon section 3 from leaking to the outside. As a result, the balloon section 3 is positioned to cover the inner tube 21 that protrudes from the opening 22a at the distal end of the outer tube 22.

[0027] The inside of the balloon section 3 is airtight except for the opening 22a at the distal end of the outer tube 22, forming a balloon space 3S. The balloon space 3S communicates only with the second lumen 22L formed inside the outer tube 22. By adjusting the amount of fluid introduced from the second lumen 22L to the balloon space 3S by driving the pump device, the balloon section 3 can be expanded and contracted radially (in a direction perpendicular to the axial direction of the inner tube 21). The balloon section 3 is inserted into the body while wrapped around the inner tube 21 located within the balloon space 3S.

[0028] Furthermore, a sensor housing space is formed inside the tip 5, and a pressure sensor 6 for measuring blood pressure is arranged in the sensor housing space. As the pressure sensor 6, for example, a sensor capable of measuring pressure using light can be used. In this embodiment, the distal end of an optical fiber 7 is connected to the pressure sensor 6, and the pressure can be detected by utilizing the path difference of the optical signal transmitted through the optical fiber 7.

[0029] A through-hole 52 is formed between the sensor housing space formed inside the tip tip 5 and the outside of the tip tip 5 (inside the artery). The sensor housing space and the through-hole 52 are filled with a pressure-transmitting material, and the opening of the through-hole 52, which opens on the outer surface of the tip tip 5, is covered and sealed with a resin film 53. As a result, external pressure (blood pressure) is transmitted to the pressure sensor 6 located inside the sensor housing space via the resin film 53 and the pressure-transmitting material.

[0030] The optical fiber 7 extends from its distal end, which is connected to the pressure sensor 6, toward the proximal end. The optical fiber 7 is led out into the balloon space 3S from the proximal end of the tip tip 5 through a fiber insertion hole formed axially within the tip tip 5. The fiber insertion hole is filled with a curable resin or the like when the optical fiber 7 is inserted, and the fiber insertion hole is sealed to prevent leakage of fluid from the balloon space 3S. Between the cylindrical distal end 30a and the cylindrical proximal end 30b of the balloon section 3, the optical fiber 7 is spirally wound around the inner tube 21 and introduced into the second lumen 22L through the opening 22a at the distal end of the outer tube 22, extending to the proximal end of the catheter tube 2.

[0031] A branch section 4, which is placed outside the patient's body, is connected to the proximal end of the catheter tube 2. The branch section 4 is molded separately from the catheter tube 2 and fixed to the catheter tube 2 by means of heat fusion or adhesive. The branch section 4 is made of a thermoplastic resin such as polycarbonate, polyamide, polysulfone, polyacrylate, methacrylate-butylene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, or polyetheretherketone (PEEK).

[0032] The branching section 4 is formed with a first passage 41 that communicates with the first lumen 21L of the catheter tube 2 and opens at the first port 41P, a second passage 42 that communicates with the first lumen 21L of the catheter tube 2 and opens at the second port 42P, and a third passage 43 that communicates with the second lumen 22L of the catheter tube 2 and opens at the third port 43P.

[0033] The first passage 41 is a passage for supplying and discharging fluid into the first lumen 21L. The first port 41P is connected to a pump device (not shown), which allows fluid to be supplied to and discharged from the balloon space 3S within the balloon section 3 through the first lumen 21L.

[0034] The second passage 42 is a passage for inserting an optical fiber 7 that extends axially within the first lumen 21L. The proximal end of the optical fiber 7 is bonded and fixed inside the second passage 42 and is led out to the outside from the second port 42P. The exit point for the optical fiber 7 at the second port 42P is designed to prevent fluid inside the first passage 41 and the second passage 42 from leaking to the outside.

[0035] An optical connector 8 is connected to the proximal end of the optical fiber 7. The optical connector 8 is connected to a blood pressure measuring device (not shown), and based on the fluctuations in blood pressure measured by this device, the pump device is controlled in accordance with the heartbeat, allowing the balloon portion 3 to expand and contract in short cycles of, for example, 0.4 to 1 second. Electrocardiogram information obtained from the patient can also be used to control the pump device in accordance with the heartbeat.

[0036] The third passage 43 communicates with the second lumen 22L and is a pathway that communicates with the outside (into the artery) through the through-hole 51 of the tip 5. An inner tube 21 is inserted through the third passage 43, and the proximal end of the inner tube 21 is connected to the third port 43P. The third passage 43 functions as a passage for inserting a guidewire, allowing the guidewire to be inserted from the third port 43P through the third passage 43 into the second lumen 22L.

[0037] The balloon portion 3 of the intra-aortic balloon catheter 1 in this embodiment will be described in detail with reference to Figures 2 and 3. Figure 2 is a side view of the balloon portion 3 of the intra-aortic balloon catheter 1 shown in Figure 1, and Figure 3 is a cross-sectional view along line AA shown in Figure 2. Figures 2 and 3 show the balloon portion 3 in an expanded state.

[0038] As shown in Figures 2 and 3, the balloon portion 3 is made of a thin film formed in a cylindrical shape. The distal end 30a of the balloon portion 3 is attached to the outer surface of the tip 5, and the proximal end 30b of the balloon portion 3 is attached to the outer surface of the outer tube 22. However, the space between the distal end 30a and the proximal end 30b is not fixed, and a balloon space 3S is formed inside the balloon portion 3. By introducing fluid into this balloon space 3S, the balloon portion 3 can be expanded radially. Conversely, by releasing fluid from the balloon space 3S, the balloon portion 3 can be contracted radially.

[0039] The balloon portion 3 has a distal tapered portion 31, a proximal tapered portion 32, and a body portion 33 between the tubular distal end 30a and the tubular proximal end 30b.

[0040] The distal tapered portion 31 is connected to the cylindrical distal end 30a attached to the tip 5, and is formed so that its outer diameter gradually increases towards the proximal side.

[0041] The proximal tapered portion 32 is connected to the cylindrical proximal end portion 30b attached to the outer tube 22, and is formed so that its outer diameter gradually increases toward the distal end.

[0042] The body portion 33 is positioned between the distal tapered portion 31 and the proximal tapered portion 32, with one end connected to the proximal end of the distal tapered portion 31 and the other end connected to the proximal tapered portion 32. The cross-sectional shape of the body portion 33 is formed so that when the balloon portion 3 is expanded, it becomes a uniform straight body in the longitudinal direction (the axial direction of the inner tube 21 located inside the balloon portion 3).

[0043] In other words, the balloon portion 3 is fixed at the cylindrical distal end 30a and the cylindrical proximal end 30b, with the distal tapered portion 31 tapering toward the distal end, the proximal tapered portion 32 tapering toward the proximal end, and the body portion 33 expanding into a straight body shape. As shown in Figure 3, the body portion 33 in this embodiment is formed to expand into a cylindrical shape, but it may also expand into a polygonal cylindrical shape, for example.

[0044] The following describes the size of balloon section 3 (balloon size).

[0045] The length of the balloon portion 3 (balloon length L) is defined as shown in Figure 2. Specifically, the balloon length L is the length between the boundary between the cylindrical distal end 30a and the distal tapered portion 31 (the distal end of the distal tapered portion 31) and the boundary between the cylindrical proximal end 30b and the proximal tapered portion 32 (the proximal end of the cylindrical proximal end 30b). The balloon length L is the longitudinal length of the portion of the balloon portion 3 that expands when fluid is introduced into the inside of the balloon portion 3 (balloon space 3S), and is the sum of the lengths of the distal tapered portion 31, the proximal tapered portion 32, and the body portion 33 of the balloon portion 3 when expanded.

[0046] The outer diameter (balloon diameter D) of the balloon portion 3 is defined as shown in Figures 2 and 3. Specifically, the balloon diameter D is the size of the cross-section of the body portion 33 when the balloon portion 3 is fully expanded by introducing fluid into the balloon space 3S. In the case of a body portion 33 that expands into a cylindrical shape, the cross-section of the body portion 33 when expanded is a perfect circle, and its diameter is the balloon diameter D. In the case of a body portion 33 that expands into a polygonal tube shape, the cross-section of the body portion 33 when expanded is a polygon, and the diameter of the circumscribed circle of that polygon is the balloon diameter D.

[0047] In this embodiment, the balloon portion 3 is formed such that the balloon diameter D is greater than a certain ratio to the balloon length L, taking into consideration the ratio of the balloon diameter D to the balloon length L when the balloon portion 3 is expanded. More specifically, the balloon diameter D when the balloon portion 3 is expanded is greater than D:L = 1:9 to the balloon length L. That is, the balloon diameter D and balloon length L satisfy the condition that the ratio of balloon length L to balloon diameter D (L / D) is less than 9 (inequality L / D < 9).

[0048] The overall size of the balloon section 3 should preferably be selected appropriately according to the patient's age and physique. The balloon volume of the balloon section 3 (the volume of the balloon space 3S when expanded) is not particularly limited, but is, for example, 20 to 50 mL.

[0049] The balloon length L is preferably such that it fits within the patient's descending aorta, for example, 30 to 260 mm. The lengths of the distal tapered portion 31, the proximal tapered portion 32, and the body portion 33 of the balloon portion 3 during expansion are not particularly limited.

[0050] The balloon diameter D can be determined in relation to the balloon length L such that it satisfies the inequality L / D < 9 described above and secures a predetermined balloon volume. Furthermore, in the balloon portion 3 of the intra-aortic balloon catheter 1 used in a typical adult male, the balloon diameter D may be 18 mm or more. As an example, the intra-aortic balloon catheter 1 in this embodiment can have a balloon diameter D of 18 mm and a balloon length L of 147 mm. This is based on the understanding that even if the balloon portion 3 expands to a size larger than the aortic diameter and occludes the aorta, blood flow will not be obstructed, thus allowing the balloon diameter D to be larger than conventional designs.

[0051] As described above, the intra-aortic balloon catheter 1 in this embodiment is configured such that the balloon diameter D of the balloon portion 3 during expansion is greater than D:L = 1:9 relative to the balloon length L. This configuration further enhances the effectiveness of IABP and more effectively improves blood flow to side branches. This allows for appropriate support of the patient's cardiac function and improvement of blood flow and hemodynamics. [Examples]

[0052] The following describes specific examples related to the present invention. However, the present invention is not limited to the following examples.

[0053] The inventors conducted an experiment to verify the relationship between balloon size and peripheral blood flow of an intra-aortic balloon catheter (hereinafter sometimes referred to as "IABP balloon") used in IABP. In this experiment, adult beagle dogs were used as experimental animals (model animals), but the experimental results can be said to be useful in considering balloon sizes applicable to humans. In this experiment, the IABP balloon used had the same configuration as the embodiment shown in Figure 1, and the balloon portion of each balloon size was manufactured by molding polyurethane using a dipping molding method, with the ratio of the longitudinal lengths of the distal tapered portion:body portion:proximal tapered portion being 1:8:1.

[0054] An adult Beagle (8.4 kg) was prepared as an experimental animal. After sedation with intravenous injection of propofol (5.0 mg / kg), slow induction was performed with oxygen and isoflurane (5.0%), and tracheal intubation was performed after sufficient sedation was achieved. Anesthesia was maintained with air, oxygen, and isoflurane (0.8-1.5%), and rocuronium (5.0 mg / h) was continuously infused intravenously as muscle relaxant.

[0055] As schematically shown in Figure 4, circulatory system parameters were measured at a specific location.

[0056] An electrocardiogram was recorded from the body surface, and aortic pressure (AP) was measured by exposing the right common carotid artery and placing a pressure-sensing catheter (SPR-330, Millar, USA) in the ascending aorta.

[0057] In addition, the left common carotid artery was exposed, and an ultrasound flow probe (MA2.5PSB, Transonic, USA) was attached to measure common carotid artery blood flow (CCA-F).

[0058] In each experiment, an IABP balloon of the balloon size described below was prepared. The IABP balloon was specially made to fit the size of a Beagle dog and was inserted through the left femoral artery. An IABP console (ZUIRYU, manufactured by Zeon Medical Co., Ltd., JPN) was used as the pumping device, and the IABP balloon was driven with an assist ratio (cardiac beat: balloon expansion / contraction cycle) of 1:1 in electrocardiogram synchronization.

[0059] Ivabradine (Hydrochloride, Tokyo Chemical Industry Co., Ltd., JPN) was administered by continuous intravenous infusion at a rate of 0.4 mg / h·kg to induce sinus bradycardia. Then, electrode leads were placed directly in contact with the right atrium, and the heart was stimulated at a pace of 95 beats / min, 110 beats / min, or 130 beats / min using an external cardiac stimulator (External Pacemaker 3077, Ospica Medical, DEU) to stabilize the heart rate. Under fluoroscopy, the placement of the IABP balloon in the descending aorta was confirmed. After the patient was sufficiently stable without activating the IABP, the IABP balloon was activated with an assist ratio of 1:1 in ECG synchronization.

[0060] All analog signals measured at each site were amplified, digitally converted to 200Hz (PowerLab 16 / 30, AD Instruments, AUS), recorded on a hard disk, and analyzed. For each measurement result at each site, the change in the average value of 4 heartbeats between the baseline (without IABP balloon operation) and 10 seconds after IABP balloon operation was calculated for each experiment.

[0061] Figure 5 shows an example of the measurement results for common carotid artery blood flow (CCA-F). As shown in Figure 5, the common carotid artery blood flow changes before and after IABP balloon activation due to the action of the IABP balloon, and an increase in blood flow due to the diastric augmentation effect of IABP and a decrease in blood flow due to the systolic unloading effect can be confirmed.

[0062] (Example 1) Under the conditions described above, circulatory parameters were measured at heart rates of 95 beats / min, 110 beats / min, and 130 beats / min using an IABP balloon A1 with a balloon diameter D of 8 mm, a balloon length L of 50 mm, and a balloon volume of 1.83 mL. The ratio of balloon length L to balloon diameter D for IABP balloon A1 (L / D) is 6.3. Table 1 shows the changes in aortic pressure and common carotid artery blood flow due to the systolic unloading effect at each heart rate for the balloon size of IABP balloon A1.

[0063] (Comparative Example 1) Under the conditions described above, circulatory parameters were measured at heart rates of 95 beats / min, 110 beats / min, and 130 beats / min using an IABP balloon B1 with a balloon diameter D of 6 mm, a balloon length L of 100 mm, and a balloon volume of 1.85 mL. The ratio of balloon length L to balloon diameter D for IABP balloon B1 (L / D) is 16.7. Table 1 shows the balloon size of IABP balloon B1 and the changes in aortic pressure and common carotid artery blood flow due to the systolic unloading effect at each heart rate.

[0064] [Table 1]

[0065] Although IABP balloon A1 and IABP balloon B1 have similar balloon volumes, the ratio L / D for IABP balloon A1 is 6.3, while the ratio L / D for IABP balloon B1 is 16.7. From Table 1, it can be said that in IABP balloon A1, where the balloon diameter D during expansion is greater than D:L = 1:9 relative to the balloon length L, the absolute values ​​of the changes in aortic pressure and common carotid artery blood flow due to the systolic unloading effect are larger at all heart rates, indicating that the effect of IABP is more pronounced (comparison between Example 1 and Comparative Example 1).

[0066] Furthermore, similar experiments were conducted with yet another IABP balloon.

[0067] (Example 2) Under the conditions described above, circulatory parameters were measured at heart rates of 95 beats / min, 110 beats / min, and 130 beats / min using an IABP balloon A2 with a balloon diameter D of 6 mm, a balloon length L of 50 mm, and a balloon volume of 0.96 mL. The ratio of balloon length L to balloon diameter D for IABP balloon A2 (L / D) is 8.3. Table 2 shows the changes in aortic pressure and common carotid artery blood flow due to the systolic unloading effect for IABP balloon A2 at each heart rate.

[0068] (Comparative Example 2) Under the above conditions, circulatory parameters were measured at heart rates of 95 beats / min, 110 beats / min, and 130 beats / min using an IABP balloon B2 with a balloon diameter D of 4 mm, a balloon length L of 150 mm, and a balloon volume of 1.05 mL. The ratio of balloon length L to balloon diameter D for IABP balloon B2 (L / D) is 37.5. Table 2 shows the changes in aortic pressure and common carotid artery blood flow due to the systolic unloading effect at each heart rate for the balloon size of IABP balloon B2.

[0069] [Table 2]

[0070] Although IABP balloon A2 and IABP balloon B2 have similar balloon volumes, the L / D ratio for IABP balloon A2 is 8.3, while the L / D ratio for IABP balloon B2 is 37.5. From Table 2, in IABP balloon A2, where the balloon diameter D during expansion is greater than D:L = 1:9 relative to the balloon length L, the absolute values ​​of the changes in aortic pressure and common carotid artery blood flow due to the systolic unloading effect are larger at all heart rates, indicating that the IABP effect is more pronounced (comparison between Example 2 and Comparative Example 2).

[0071] Furthermore, although IABP balloons A1 and B1 differ significantly in balloon volume from IABP balloons A2 and B2, Tables 1 and 2 show that the effect of IABP is greater as the balloon volume increases (comparison between Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2). This suggests that increasing the balloon diameter D can secure a larger balloon volume and improve the effect of IABP.

[0072] The embodiments described above are provided to facilitate understanding of the present invention and do not limit it. The components disclosed in the embodiments described above are intended to include all design modifications and equivalents that fall within the technical scope of the present invention. Furthermore, configurations obtained by appropriately combining the components described in each embodiment are also included in the present invention. [Explanation of Symbols]

[0073] 1. Intra-aortic balloon catheter 2 Catheter tube 2M contrast marker 3. Balloon section 3S Balloon Space 4 Branching point 5 Tip 6. Pressure Sensor 7 Fiber Optics 8 Optical connectors 21 Inner tube 21L, 1st Lumen 22 Outer tube 22a opening 22L, 2nd Lumen 30a Tubular distal end 30b Tubular proximal end 31 Distal tapered section 32 Proximal tapered section 33 Torso 41 1st aisle 41P Port 1 42 2nd aisle 42P Port 2 43 3rd aisle 43P Third Port 51 Through hole 52 Through hole 53 Resin film

Claims

[Claim 1] An intra-aortic balloon catheter used in IABP, Catheter tube and The catheter tube has a balloon portion attached to its distal end, which can be expanded and contracted by supplying and discharging fluid into it, An intra-aortic balloon catheter characterized in that the balloon diameter D when the balloon portion is expanded is greater than D:L = 1:9 with respect to the balloon length L.

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