Balloon catheter for iabp

Abstract

To provide a balloon catheter for IABP capable of improving effects of the IABP by appropriately assisting blood flow generation during IABP implementation.SOLUTION: A balloon catheter 10 for IABP includes a catheter tube 30, a distal tip 20 attached to a distal end of the catheter tube 30, and a balloon 40 provided at the distal end of the catheter tube 30 and inflatable by fluid supplied from a proximal side of the catheter tube 30, where the balloon 40 is comprised of a balloon matrix 100 formed in a cylindrical shape, a proximal end 130 of the balloon matrix 100 is joined to the catheter tube 30, and a distal end 120 of the balloon matrix 100 is joined to the distal tip 20 or the catheter tube 30 in a state where it is rotated by a prescribed angle or more in a circumferential direction with respect to the proximal end 130 of the balloon matrix 100 attached to the catheter tube 30.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a balloon catheter for IABP (Intra-Aortic Balloon Pumping) that is inserted into the body for IABP. [Background technology]

[0002] IABP has traditionally been known as one of the methods of assisting cardiac function. In IABP, a balloon is generally placed in the descending thoracic aorta, and the balloon expands and contracts in time with the heartbeat. The balloon expands during systole to increase blood flow to the coronary arteries, and contracts during diastole to facilitate blood flow from the heart to the entire body via the descending thoracic aorta, thereby assisting cardiac function.

[0003] The balloon catheter used in IABP has an expandable and contractible balloon attached to the distal end of the catheter tube, and is configured so that the balloon can be expanded and contracted by controlling the amount of fluid, such as helium gas, that is pumped into the balloon from the proximal side of the catheter tube (for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-130883 Summary of the Invention [Problem to be solved by the invention]

[0005] IABP involves the inflation and deflation of a balloon, which can disrupt the blood flow around the balloon, making it difficult for blood to flow in the desired direction, reducing the amount of blood flowing to the coronary arteries and the entire body, and potentially reducing the effectiveness of the IABP.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an IABP balloon catheter that can appropriately assist in generating blood flow when IABP is performed, thereby improving the effectiveness of IABP. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an IABP balloon catheter comprising a catheter tube, a distal tip attached to the distal end of the catheter tube, and a balloon provided at the distal end of the catheter tube and inflatable with a fluid supplied from the proximal side of the catheter tube, wherein the balloon is constituted by a tubular balloon matrix, the proximal end of the balloon matrix is ​​joined to the catheter tube, and the distal end of the balloon matrix is ​​joined to the distal tip or the catheter tube in a state rotated by a predetermined angle in the circumferential direction with respect to the proximal end of the balloon matrix attached to the catheter tube.

[0008] According to the above configuration, the balloon matrix constituting the balloon is attached to the distal end of the catheter tube with the distal joint rotated circumferentially by a predetermined angle or more relative to the proximal joint. As a result, when the balloon is inflated, it expands while rotating around its axis, and this rotation can generate blood flow toward the distal side (coronary artery side). When the balloon is deflated, it contracts while rotating around its axis, and this rotation can generate blood flow toward the proximal side (descending thoracic aorta side). As a result, blood flow generation can be appropriately assisted when IABP is performed, improving the cardiac function support effect of IABP. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram schematically illustrating a state in which a balloon of an IABP balloon catheter according to an embodiment of the present invention is placed in the descending thoracic aorta. [Figure 2] 1 is a cross-sectional view showing the configuration of an IABP balloon catheter according to an embodiment of the present invention. [Figure 3] FIG. 1 is a diagram illustrating an example of a method for fabricating a balloon by attaching a balloon matrix to the distal end of an IABP balloon catheter in the prior art, where (a) to (c) are diagrams showing the first to third steps, respectively. [Figure 4] 1A to 1D are diagrams illustrating an example of a method for fabricating a balloon by attaching a balloon matrix to the distal end of an IABP balloon catheter in an embodiment of the present invention, and show the first to fourth steps, respectively. [Figure 5] 1A and 1B are diagrams for explaining the operation when the balloon of an IABP balloon catheter in an embodiment of the present invention is inflated and deflated, in which (a) shows the state in which the balloon is deflated and (b) shows the state in which the balloon is inflated. [Figure 6] 10A and 10B are diagrams showing another example of a balloon of an IABP balloon catheter according to an embodiment of the present invention. [Figure 7]FIG. 1 is a diagram illustrating an experimental system for confirming the function of the balloon of an IABP balloon catheter according to an embodiment of the present invention. [Figure 8] 1 is a graph showing results of experiments conducted in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The drawings referred to in this specification do not necessarily have accurate scales relative to actual dimensions, and some parts are exaggerated or simplified to schematically illustrate the configuration according to the present invention.

[0011] In the present embodiment, the IABP balloon catheter 10 has a balloon 40 provided near the distal end, which is placed in the descending thoracic aorta, and the balloon 40 expands and contracts in accordance with the heartbeat to assist cardiac function, as shown in FIG.

[0012] As an example, Figure 1 shows a state in which the balloon 40 of an IABP balloon catheter 10 inserted through the femoral artery is placed in the descending thoracic aorta. Figure 1 illustrates the distal tip 20, catheter tube 30, and balloon 40 that make up the IABP balloon catheter 10.

[0013] FIG. 2 is a cross-sectional view showing the configuration of an IABP balloon catheter 10 according to an embodiment of the present invention.

[0014] As shown in Figure 2, the IABP balloon catheter 10 has a distal tip 20, a catheter tube 30, a balloon 40, and a bifurcation 50. In Figure 2, a portion of the catheter tube 30 is cut away and not shown, but in reality, the catheter tube 30 is connected, and the IABP balloon catheter 10 has a long shape. In this specification, the direction in which the IABP balloon catheter 10 extends is referred to as the axial direction, the distal tip 20 side of the IABP balloon catheter 10 is referred to as the distal side, and the bifurcation 50 side of the IABP balloon catheter 10 is referred to as the proximal side.

[0015] The distal tip 20 is a component located at the distal end of the IABP balloon catheter 10. The distal tip 20 has a cylindrical shape, and its distal end is formed in a rounded, tapered shape to enable good insertion into the artery and to avoid damaging the arterial wall. A through-hole 21 is formed axially inside the distal tip 20, and an inner tube 31 is inserted and fixed into the through-hole 21. A distal joint 42a located at the distal end of the balloon 40 is joined to the outer peripheral surface on the proximal side of the distal tip 20.

[0016] There are no particular limitations on the material of the distal tip 20, and examples that can be used include polymeric materials such as resins (e.g., polyurethane and polyamide), elastomers, and metal materials (e.g., stainless steel). In order to provide contrast in X-ray fluoroscopic images, the material of the distal tip 20 may contain a contrast agent, or metal may be embedded in the distal tip 20.

[0017] The size of the distal tip 20 is not particularly limited, and for example, the axial dimension of the distal tip 20 is 5 to 25 mm, the outer diameter is 1.6 to 3.4 mm, and the inner diameter is 0.1 to 1.5 mm. Since the inner tube 31 is inserted into the through-hole 21, it is preferable that the inner diameter of the proximal side of the through-hole 21 is equal to the outer diameter of the distal end of the inner tube 31.

[0018] The catheter tube 30 is composed of an inner tube 31 and an outer tube 32, each of which has a tubular shape extending in the axial direction. Figure 2 shows a balloon catheter with a double lumen structure as an example of the IABP balloon catheter 10.

[0019] The inner diameter of the outer tube 32 is larger than the outer diameter of the inner tube 31, and the inner tube 31 is inserted into the lumen of the outer tube 32. A portion of the outer peripheral surface of the inner tube 31 is fixed to a portion of the inner peripheral surface of the outer tube 32 over part or all of the axial direction of the inner tube 31. In addition, in order to provide contrast in X-ray fluoroscopic images, a metallic X-ray fluoroscopy member may be provided near the distal end of the inner tube 31 or the outer tube 32. This X-ray fluoroscopy member is sometimes called a contrast marker.

[0020] The distal end of the outer tube 32 terminates near the proximal joint 43a of the balloon 40 and opens into the space inside the balloon 40, and the proximal end of the outer tube 32 is joined to the outer tube fixing part 51 of the branching part 50. Meanwhile, both ends of the inner tube 31 inserted into the lumen of the outer tube 32 protrude from the outer tube 32. The distal end of the inner tube 31 passes through the space inside the balloon 40 and is inserted into and fixed to the through-hole 21 of the distal tip 20, and the proximal end of the inner tube 31 passes through the side branch part 53 of the branching part 50 and is connected to the blood pressure measurement port 56.

[0021] A first lumen 31L is formed inside the inner tube 31, and a second lumen 32L is formed inside the outer tube 32 but outside the inner tube 31. The first lumen 31L and the second lumen 32L are isolated from each other.

[0022] The first lumen 31L communicates with the through-hole 21 of the distal tip 20 on the distal side of the inner tube 31, and communicates with the blood pressure measurement port 56 of the branching part 50 on the proximal side of the inner tube 31, as described below. The first lumen 31L is used as a blood flow path that takes in blood for blood pressure measurement and as a passage through which a guide wire can be inserted.

[0023] The second lumen 32L communicates with the space inside the balloon 40 on the distal side of the outer tube 32, and communicates with a fluid supply / discharge port 55 of the branching section 50 on the proximal side of the outer tube 32, as will be described later. The second lumen 32L is used as a supply / discharge path that can supply and discharge fluid through the fluid supply / discharge port 55, and the balloon 40 can be expanded and deflated by supplying and discharging fluid through this supply / discharge path.

[0024] Here, a configuration in which both ends of the inner tube 31 protrude from the outer tube 32 is given as an example, but it is also possible to configure the inner tube 31 to terminate at the same end face as one or both ends of the outer tube 32, and to connect another tubular member to the end of the inner tube 31, so that the other tubular member protrudes from one end or both ends of the outer tube 32.

[0025] The material of the catheter tube 30 is not particularly limited, but is preferably flexible, and examples of materials that can be used include resin materials such as polyurethane, polyvinyl chloride, polyethylene, polyamide, and polyether ether ketone (PEEK), and metal materials such as nickel-titanium alloy and stainless steel. The materials of the inner tube 31 and the outer tube 32 may be the same or different. For example, the inner tube 31 of the catheter tube 30 is made of a PEEK tube, and the outer tube 32 is made of a polyamide tube, with the outer surface of the outer tube 32 coated with polyurethane, which has excellent antithrombogenic properties.

[0026] The size of the inner tube 31 is not particularly limited, and for example, the axial dimension of the inner tube 31 is 500 to 1100 mm, the inner diameter is 0.1 to 2.0 mm, and the wall thickness is 0.05 to 0.4 mm. The size of the outer tube 32 is not particularly limited, and the inner diameter of the outer tube 32 is set to be larger than the outer diameter of the inner tube 31, and for example, the axial dimension of the outer tube 32 is 300 to 800 mm, the inner diameter is 1.0 to 4.0 mm, and the wall thickness is 0.05 to 0.4 mm.

[0027] The balloon 40 is a cylindrical thin film that can expand and contract when a fluid is supplied to and discharged from the interior thereof, and is disposed at the distal end of the IABP balloon catheter 10. More specifically, the balloon 40 has an inflation / deflation section 41, a distal tapered section 42, and a proximal tapered section 43. The inflation / deflation section 41 is disposed at the axial center of the balloon 40 and is configured such that the outer diameter expands uniformly in the axial direction into a straight cylindrical shape when a fluid is supplied to and discharged from the interior of the balloon 40. The distal tapered section 42 is disposed distal to the inflation / deflation section 41 and is tapered such that the outer diameter decreases distally. The proximal tapered section 43 is disposed proximal to the inflation / deflation section 41 and is tapered such that the outer diameter decreases proximally.

[0028] The distal end of the distal tapered section 42 forms a distal joint 42a. The distal joint 42a is joined to the outer circumferential surface of the proximal side of the distal tip 20. The space inside the balloon 40 is closed near the distal joint 42a. In this embodiment, the distal joint 42a of the balloon 40 is joined to the distal tip 20, but it may also be joined to the outer circumferential surface of the inner tube 31 located proximal to the distal tip 20, or it may be joined so as to straddle both the distal tip 20 and the inner tube 31.

[0029] Meanwhile, the proximal end of the proximal tapered section 43 forms a proximal joint 43a. The proximal joint 43a is joined to the outer peripheral surface of the distal side of the outer tube 32. Near the proximal joint 43a, the space inside the balloon 40 communicates with the second lumen 32L via an opening at the distal end of the outer tube 32. Fluid is supplied to and discharged from the space inside the balloon 40 through the second lumen 32L and the fluid supply / discharge port 55, allowing the balloon 40 to expand and contract depending on the amount of fluid supplied and discharged. Note that the method for joining the distal joint 42a and the proximal joint 43a of the balloon 40 to the distal tip 20 or the catheter tube 30 (the inner tube 31 or the outer tube 32) is not particularly limited, and examples of suitable methods include bonding using an adhesive, heat fusion, solvent welding, and ultrasonic welding.

[0030] The IABP balloon catheter 10 is used with its distal end inserted into an artery via the femoral artery or brachial artery, and the balloon 40 placed in the descending thoracic aorta. When inserted into the artery, the balloon 40 is inserted in close contact with the inner tube 31, and after being placed in the descending thoracic aorta, it is expanded and deflated by fluid.

[0031] The material of the balloon 40 is not particularly limited, but is preferably a material with excellent resistance to bending fatigue, such as a resin material such as polyurethane. The size of the balloon 40 is not particularly limited, and is determined according to the internal volume of the balloon 40 and the inner diameter of the arterial blood vessel, which greatly affect the cardiac function support effect. For example, the internal volume of the balloon 40 is 20 to 50 ml, the membrane thickness is 20 to 200 μm, the outer diameter (when expanded) is 10 to 25 mm, and the axial dimension is 110 to 300 mm.

[0032] The branching section 50 is a molded body having an inner cavity with openings at three locations: an outer tube insertion port 54, a fluid supply / discharge port 55, and a blood pressure measurement port 56, and is composed of an outer tube fixing section 51, a main trunk 52, and a side branch section 53.

[0033] The outer tube fixing part 51 is a part on the distal side of the branching part 50, and has an outer tube insertion port 54 on its distal side. The proximal end of the outer tube 32 is inserted into the outer tube insertion port 54, and the outer tube 32 is fixed by the outer tube fixing part 51. The outer tube 32 opens into the lumen of the branching part 50 at the outer tube fixing part 51.

[0034] The main trunk 52 is one of the parts branched into two from the outer tube insertion port 54 of the outer tube fixing part 51, and has a fluid supply / discharge port 55 on its proximal side. The fluid supply / discharge port 55 communicates with the outer tube insertion port 54 where the outer tube 32 opens, i.e., the fluid supply / discharge port 55 communicates with the second lumen 32L.

[0035] The fluid supply / discharge port 55 is connected to an IABP drive device (not shown) and is capable of supplying fluid to the space inside the balloon 40 through the second lumen 32L and discharging the fluid from the space. With the balloon 40 placed in the descending thoracic aorta, the balloon 40 is inflated and deflated in accordance with the heartbeat while controlling the amount and timing of fluid supply and discharge, thereby assisting cardiac function. The fluid used to inflate and deflate the balloon 40 is not particularly limited, but in consideration of safety and responsiveness to the drive of the IABP drive device, for example, helium gas, an inert gas with low viscosity and mass, is used.

[0036] Side branch portion 53 is the other part that branches into two from the opening of outer tube fixing portion 51, and has blood pressure measurement port 56 on its proximal side. Blood pressure measurement port 56 is connected to inner tube 31, that is, blood pressure measurement port 56 communicates with first lumen 31L.

[0037] The blood pressure measurement port 56 is connected to a blood pressure measurement device (not shown), and is capable of measuring fluctuations in arterial blood pressure through the through-hole 21 and first lumen 31L of the distal tip 20. By controlling the drive of the IABP drive device based on the fluctuations in blood pressure measured by this blood pressure measurement device, it becomes possible to inflate and deflate the balloon 40 in accordance with the heartbeat.

[0038] The blood pressure measurement port 56 also functions as a guidewire insertion port used when inserting the IABP balloon catheter 10. When placing the balloon 40 in the descending thoracic aorta, the distal end of the IABP balloon catheter 10, with a guidewire inserted through the first lumen 31L and the through-hole 21 of the distal tip 20, is inserted from the blood pressure measurement port 56 into the femoral artery or brachial artery, and the balloon 40 can be guided and placed in the descending thoracic aorta by advancing the distal end of the IABP balloon catheter 10 along the guidewire while leading the guidewire forward. A guidewire with an outer diameter smaller than the inner diameter of the inner tube 31 and capable of passing through the inner tube 31 is used.

[0039] The material of the branching portion 50 is not particularly limited, and for example, a thermoplastic resin material such as ABS (acrylonitrile butadiene styrene copolymer), polystyrene, polypropylene, polycarbonate, etc. can be used, and a molding die may be used to form the branching portion 50. The size (axial dimension) of the branching portion 50 is not particularly limited, and is, for example, 10 to 150 mm.

[0040] The balloon 40 of the IABP balloon catheter 10 of this embodiment will be described in detail below.

[0041] In order to clearly explain the characteristics of the balloon 40 of the IABP balloon catheter 10 of this embodiment, the balloon 240 of the IABP balloon catheter 200 according to the prior art will first be described with reference to Figure 3. Figure 3 is a diagram illustrating an example of a method for fabricating the balloon 240 by attaching the balloon matrix 100 to the distal end of the IABP balloon catheter 200 according to the prior art, with (a) to (c) showing the first to third steps, respectively.

[0042] In the prior art, when providing a balloon 240 at the distal end of an IABP balloon catheter 200, first a balloon matrix 100 that constitutes the balloon 240 is prepared. The balloon matrix 100 is a member in which a thin film is formed into a cylindrical shape, and can be obtained by molding the material that constitutes the balloon 240 (e.g., a resin material such as polyurethane) using a method such as blow molding or dip molding. The lumen of the balloon matrix 100 is open at both the distal and proximal ends.

[0043] The balloon matrix 100 has a body portion 110 in its axial center, a distal end portion 120 distal to the body portion 110, and a proximal end portion 130 proximal to the body portion 110.

[0044] When the balloon matrix 100 is attached to the distal end of the IABP balloon catheter 200 to form the balloon 240, the body portion 110 of the balloon matrix 100 forms the inflation / deflation portion 241 of the balloon 240. The distal end portion 120 of the balloon matrix 100 forms the distal tapered portion 242 and distal junction portion 242a of the balloon 240, and the proximal end portion 130 of the balloon matrix 100 forms the proximal tapered portion 243 and proximal junction portion 243a of the balloon 240.

[0045] Here, the distal end portion 120 and the proximal end portion 130 of the balloon matrix 100 are also formed to have a tapered shape in advance to match the shapes of the distal tapered portion 242, the distal joint portion 242a, the proximal tapered portion 243, and the proximal joint portion 243a of the balloon 240, but the distal end portion 120 and the proximal end portion 130 of the balloon matrix 100 may also have an inner diameter that is uniform in the axial direction.

[0046] When no external force is applied (hereinafter referred to as the natural state), the balloon matrix 100 is not twisted in the circumferential direction and extends straight in the axial direction. To illustrate this natural state without twisting in the circumferential direction, in Figures 3(a) to 3(c), a linear marker line M (the marker line ends Ma, Mb are highlighted with circles) is drawn on the outer peripheral surface of the body portion 110 of the balloon matrix 100 along the axial direction of the balloon matrix 100.

[0047] 3(a), the inner tube 31 to which the distal tip 20 is attached is inserted into the lumen of the balloon matrix 100, with the distal end 120 of the balloon matrix 100 positioned near the distal tip 20 and the proximal end 130 of the balloon matrix 100 positioned near the distal end of the outer tube 32. At this time, the marker line M drawn on the outer peripheral surface of the body 110 is approximately parallel to the inner tube 31 inserted into the lumen of the balloon matrix 100.

[0048] 3(b), the proximal end portion 130 of the balloon matrix 100 is bonded to the outer peripheral surface of the outer tube 32. The proximal side of the proximal end portion 130 is bonded to the outer peripheral surface of the outer tube 32 to form the proximal bonded portion 243a of the balloon 240. The proximal bonded portion 243a is bonded in close contact with the outer peripheral surface of the outer tube 32 so that the fluid inside the balloon 240 does not leak from the proximal bonded portion 243a to the outside of the balloon 240.

[0049] 3(c), the distal end 120 of the balloon matrix 100 is bonded to the outer peripheral surface of the tip 20. The distal side of the distal end 120 is bonded to the outer peripheral surface of the tip 20 to form the distal joint 242a of the balloon 240. The distal joint 242a is bonded in close contact with the outer peripheral surface of the tip 20 so that the fluid inside the balloon 240 does not leak from the distal joint 242a to the outside of the balloon 240.

[0050] As described above, in the prior art, the balloon matrix 100 is attached to the distal end of the IABP balloon catheter 200 with the body 110 not twisted, thereby forming the balloon 240. In the balloon 240 attached to the distal end of the IABP balloon catheter 200 according to the prior art, the marker line M drawn on the outer peripheral surface of the body 110 of the balloon matrix 100 constituting the balloon 240 is positioned so as to be approximately parallel to the inner tube 31, as shown in FIG. 3(c).

[0051] The balloon 40 of the IABP balloon catheter 10 in this embodiment will be described below with reference to Fig. 4. Fig. 4 is a diagram for explaining an example of a method for fabricating a balloon 240 by attaching a balloon matrix 100 to the distal end of the IABP balloon catheter 10 in this embodiment, with (a) to (d) showing first to fourth steps, respectively.

[0052] In this embodiment, similar to the prior art described above with reference to Figures 3(a) to 3(c), when providing a balloon 40 at the distal end of an IABP balloon catheter 10, first a balloon matrix 100 that constitutes the balloon 40 is prepared. The balloon matrix 100 can be the same as that in the prior art described above. That is, the balloon matrix 100 in this embodiment is also a cylindrical member that has a body portion 110 in its axial center, a distal end portion 120 distal to the body portion 110, and a proximal end portion 130 proximal to the body portion 110.

[0053] When the balloon 40 is formed by attaching the balloon matrix 100 to the distal end of the IABP balloon catheter 10, the body portion 110 of the balloon matrix 100 forms the inflation / deflation portion 41 of the balloon 40. The distal end portion 120 of the balloon matrix 100 forms the distal tapered portion 42 and distal joint portion 42a of the balloon 40, and the proximal end portion 130 of the balloon matrix 100 forms the proximal tapered portion 43 and proximal joint portion 43a of the balloon 40.

[0054] In addition, in its natural state without any external force applied, the balloon matrix 100 is not twisted in the circumferential direction and extends straight in the axial direction. To illustrate this natural state without twisting in the circumferential direction, a linear marker line M (the marker line ends Ma, Mb are highlighted with circles) is drawn on the outer circumferential surface of the body portion 110 of the balloon matrix 100 along the axial direction of the balloon matrix 100 in Figures 4(a) to 4(d).

[0055] 4(a), the inner tube 31 to which the distal tip 20 is attached is inserted into the lumen of the balloon matrix 100, with the distal end 120 of the balloon matrix 100 positioned near the distal tip 20 and the proximal end 130 of the balloon matrix 100 positioned near the distal end of the outer tube 32. At this time, the marker line M drawn on the outer peripheral surface of the body 110 is approximately parallel to the inner tube 31 inserted into the lumen of the balloon matrix 100.

[0056] Next, as shown in Figure 4(b), the proximal end 130 of the balloon matrix 100 is bonded to the outer peripheral surface of the outer tube 32. The proximal side of the proximal end 130 is bonded to the outer peripheral surface of the outer tube 32 to form the proximal bonded portion 43a of the balloon 40. The proximal bonded portion 43a is bonded in close contact with the outer peripheral surface of the outer tube 32 so that fluid inside the balloon 40 does not leak from the proximal bonded portion 43a to the outside of the balloon 40. The steps up to this point are similar to the steps of the prior art shown in Figures 3(a) and 3(b).

[0057] Next, as shown in Figure 4(c), the distal end 120 of the balloon matrix 100 is rotated circumferentially by a predetermined angle. Here, the distal end 120 of the balloon matrix 100 is shown rotated 180° counterclockwise as viewed from the tip side. Because the proximal end 130 of the balloon matrix 100 is bonded to the outer peripheral surface of the outer tube 32, when the distal end 120 of the balloon matrix 100 is rotated circumferentially by a predetermined angle, the body portion 110 of the balloon matrix 100 becomes twisted.

[0058] When the body 110 is twisted, the marker line M drawn on the outer peripheral surface of the body 110 of the balloon matrix 100 is arranged in a spiral shape with the inner tube 31 inserted into the lumen of the balloon matrix 100 as the central axis. The marker line end Ma has rotated approximately 180° in the circumferential direction and moved to a position on the far side of the page. In the drawing, the marker line M that can be seen from the front side of the page is shown with a solid line, while the marker line M that cannot be seen from the front side of the page is shown with a dashed line.

[0059] 4(d), with the body portion 110 of the balloon matrix 100 in a twisted state, the distal end portion 120 of the balloon matrix 100 is bonded to the outer circumferential surface of the tip 20. The distal side of the distal end portion 120 is bonded to the outer circumferential surface of the tip 20 to form the distal bonded portion 42a of the balloon 40. The distal bonded portion 42a is bonded in close contact with the outer circumferential surface of the tip 20 so that the fluid inside the balloon 240 does not leak from the distal bonded portion 42a to the outside of the balloon 240.

[0060] As described above, in this embodiment, the distal end 120 of the balloon matrix 100 is joined to the distal tip 20 in a state where it is rotated circumferentially by a predetermined angle or more relative to the proximal end 130 of the balloon matrix 100, which is attached to the outer tube 32 of the catheter tube 30. The balloon matrix 100 is attached to the distal end of the IABP balloon catheter 10 in a twisted state, thereby constituting the balloon 40. In the balloon 40 attached to the distal end of the IABP balloon catheter 10 in this embodiment, the marker line M drawn on the outer peripheral surface of the body 110 of the balloon matrix 100 constituting the balloon 40 is arranged in a spiral shape with the inner tube 31 as the central axis, as shown in FIG. 4(d).

[0061] The predetermined angle by which the distal end portion 120 of the balloon matrix 100 is rotated in the circumferential direction is preferably 90° (1 / 4 turn) or more. As will be described later, by twisting the balloon 40, the balloon 40 expands and contracts while rotating, and the rotation of the balloon 40 generates a force to push out (extrusion force) and a force to pull in (retraction force) the fluid around the balloon 40 (blood around the balloon 40). In order to generate sufficient pushing and retraction forces on the fluid around the balloon 40, the predetermined angle is preferably at least 90° (1 / 4 turn); the larger the predetermined angle, the stronger the pushing and retraction forces can be.

[0062] On the other hand, if the predetermined angle by which the distal end 120 of the balloon matrix 100 is rotated in the circumferential direction is made too large, the balloon 40 may become difficult to inflate or may remain twisted in the inflation / deflation section 41 (the body section 110 of the balloon matrix 100) after inflation. Therefore, in order to properly inflate and deflate the balloon 40, it is preferable that the predetermined angle by which the distal end 120 of the balloon matrix 100 is rotated in the circumferential direction be 1800° (5 rotations) or less.

[0063] From the above viewpoints, the predetermined angle by which the distal end portion 120 of the balloon matrix 100 is rotated in the circumferential direction is preferably from 90° (1 / 4 rotation) to 1800° (5 rotations), more preferably from 90° (1 / 4 rotation) to 720° (2 rotations), and even more preferably from 90° (1 / 4 rotation) to 360° (1 rotation). For example, by setting the predetermined angle to 90° (1 / 4 rotation), 180° (half rotation), 360° (1 rotation), 540° (1.5 rotations), or 720° (2 rotations), a balloon 40 is realized that efficiently generates a liquid flow associated with the rotational movement and can be appropriately expanded and contracted.

[0064] The direction of rotation of the distal end portion 120 of the balloon matrix 100 in the circumferential direction is not particularly limited, and may be either clockwise or counterclockwise as viewed from the tip end side.

[0065] In the explanation given with reference to Figures 4(a) to (d), after the proximal end 130 of the balloon matrix 100 is joined to the outer tube 32 of the catheter tube 30, the distal end 120 of the balloon matrix 100 is rotated and joined to the tip chip 20; however, after the distal end 120 of the balloon matrix 100 is joined to the tip chip 20, the proximal end 130 of the balloon matrix 100 may be rotated and joined to the outer tube 32 of the catheter tube 30.

[0066] In this embodiment, the distal end 120 and the proximal end 130 of the balloon matrix 100 constituting the balloon 40 are twisted circumferentially by a predetermined angle or more. This state can be expressed as a state in which the distal bonded portion 42a of the balloon matrix 100 is rotated circumferentially by a predetermined angle or more relative to the proximal bonded portion 43a, but it can also be expressed as a state in which the proximal bonded portion 43a of the balloon matrix 100 is rotated circumferentially by a predetermined angle or more relative to the distal bonded portion 42a. Both of these expressions describe the same state.

[0067] Alternatively, the distal end 120 and the proximal end 130 of the balloon matrix 100 may be rotated relative to each other to create a twisted state beforehand, and the inner tube 31 to which the distal tip 20 is attached may be inserted into the lumen of the twisted balloon matrix 100. The bonding position of the distal end 120 of the balloon matrix 100 is not limited to the outer circumferential surface of the distal tip 20, but may also be, for example, the outer circumferential surface of the inner tube 31 located near the distal tip 20. Furthermore, the distal end 120 of the balloon matrix 100 may be bonded so as to straddle the outer circumferential surfaces of both the distal tip 20 and the inner tube 31.

[0068] The operation of the balloon 40 of the IABP balloon catheter 10 of this embodiment when it is inflated and deflated will be described below with reference to Fig. 5. Fig. 5 is a diagram for explaining the operation of the balloon 40 of the IABP balloon catheter 10 of this embodiment when it is inflated and deflated, with (a) showing the balloon 40 in a deflated state (balloon deflated state) and (b) showing the balloon 40 in an inflated state (balloon expanded state). The balloon 40 shown in Fig. 5 was produced by the method shown in Figs. 4(a) to (d), and is attached in a twisted state with the distal end 120 of the balloon matrix 100 rotated 180° circumferentially relative to the proximal end 130 of the balloon matrix 100.

[0069] In the deflated state of the balloon shown in Figure 5(a), the inflation / deflation section 41 of the balloon 40 is twisted. The balloon 40 is joined at the distal joint 42a and the proximal joint 43a so that the fluid inside the balloon 40 does not leak to the outside. By supplying fluid to the space inside the balloon 40 through the opening at the distal end of the outer tube 32, the balloon 40 can be expanded as shown in Figure 5(b).

[0070] When a fluid is supplied to the space inside the balloon 40, a force (expansion force) acts on the inflation / deflation portion 41 of the balloon 40, expanding it radially outward. This expansion force acts uniformly across the entire inner circumferential surface of the inflation / deflation portion 41. The inflation / deflation portion 41 expands radially outward to eliminate its twisted state. As a result, in the balloon's expanded state, the inflation / deflation portion 41 returns to a shape close to the natural shape of the balloon matrix 100 and expands in a straight, axially extending shape. At this time, the inflation / deflation portion 41 of the balloon 40 expands so that its cross-sectional shape is uniform in the axial direction. As shown in FIG. 5(b), the marker line M drawn on the outer circumferential surface of the inflation / deflation portion 41 is approximately parallel to the inner tube 31 inserted inside the balloon 40.

[0071] Note that because the balloon 40 itself is attached in a twisted state, rotated by a predetermined angle in the circumferential direction, the preset twist does not disappear when the balloon 40 is inflated. During inflation of the balloon 40, the twist set in the balloon 40 itself is concentrated in the distal tapered portion 42 and the proximal tapered portion 43, or the inner tube 31 rotates and twists about its axis, thereby eliminating the twist in the inflation / deflation portion 41 and allowing the inflation / deflation portion 41 to expand in a shape that extends straight in the axial direction. In this way, by expanding the inflation / deflation portion 41 in a shape that extends straight in the axial direction, it is possible to appropriately compress the inner wall of the descending thoracic aorta when IABP is performed.

[0072] When the fluid is discharged from the space inside the balloon 40 through the opening at the distal end of the outer tube 32 in the expanded state, the balloon returns to the deflated state shown in Fig. 5(a). At this time, the expansion force acting on the expansion / contraction portion 41 of the balloon 40 decreases, and the expansion / contraction portion 41 returns to its twisted state.

[0073] When the balloon 40 of this embodiment is inflated, the expansion / contraction section 41 expands from a deflated and twisted state to a straight, elongated shape. At this time, the expansion / contraction section 41 does not simply expand in the radial direction, but also expands with a rotational movement that eliminates the twist.

[0074] Furthermore, when the balloon 40 of this embodiment is deflated, the expansion / contraction section 41 contracts from its expanded, straight shape to a twisted, deflated state. At this time, the expansion / contraction section 41 does not simply contract radially but also rotates to return to its original twisted state.

[0075] In other words, the balloon 40 in this embodiment is configured to be inflated and deflated while rotating like a screw. In this way, the balloon 40 expands and contracts while rotating, thereby appropriately assisting in the generation of blood flow when IABP is performed, thereby improving the effectiveness of IABP.

[0076] When performing IABP, a balloon 40 is placed in the descending thoracic aorta as shown in FIG. 1, and the balloon 40 is inflated during cardiac systole and deflated during cardiac diastole.

[0077] In order to increase the amount of blood flowing into the coronary arteries during cardiac systole, it is desirable to create a blood flow that pushes blood toward the distal side of the balloon 40. The balloon 40 in this embodiment is configured to expand with rotational movement about its axis, and is able to generate a pushing force that pushes blood toward the distal side of the balloon 40. As a result, a blood flow toward the coronary arteries (distal-directed blood flow) can be created on the distal side of the balloon 40, thereby increasing the amount of blood flowing into the coronary arteries.

[0078] Furthermore, in order to increase the amount of blood flowing from the heart toward the descending thoracic aorta during cardiac diastole, it is desirable to create a blood flow that draws blood toward the distal side of the balloon 40. The balloon 40 in this embodiment is configured to contract while rotating about its axis, and a retraction force that draws blood can be generated on the distal side of the balloon 40. As a result, a blood flow toward the descending thoracic aorta (blood flow toward the proximal side) can be created on the distal side of the balloon 40, thereby increasing the amount of blood flowing from the heart to the descending thoracic aorta.

[0079] Figure 6 shows another example of the balloon 40 of the IABP balloon catheter 10 according to this embodiment. The balloon 40 shown in Figure 6 is attached in a twisted state, with the distal end 120 of the balloon matrix 100 rotated 360° in the circumferential direction relative to the proximal end 130 of the balloon matrix 100. The balloon 40 shown in Figure 6 differs from the balloon 40 shown in Figure 5 only in the angle of rotation when the balloon matrix 100 is attached, i.e., the strength of the twist.

[0080] In the deflated state of the balloon, the marker line M drawn on the outer peripheral surface of the inflation / deflation section 41 of the balloon 40 is arranged in a spiral shape with the inner tube 31 inserted inside the balloon 40 as the central axis. The marker line M goes around in the circumferential direction, and both of the marker line ends Ma and Mb are positioned so that they can be seen from the front side of the page.

[0081] When the balloon 40 shown in Figure 6 is inflated, the inflation / deflation section 41 returns to a shape close to the natural state of the balloon body 100, and expands in a shape that extends straight in the axial direction, similar to the balloon 40 that is attached in a twisted state by rotating 180 degrees (see Figure 5(b)).

[0082] The balloon 40 shown in FIG. 6 also expands and contracts with a rotational movement, and can appropriately assist in generating blood flow when IABP is performed, thereby improving the effect of IABP.

[0083] The greater the angle of rotation when the balloon matrix 100 is attached, the stronger the push-out and pull-in forces that are generated by the rotational movement during inflation and deflation of the balloon 40. Therefore, the balloon 40 shown in Fig. 6 has a stronger blood flow generation assist function than the balloon 40 shown in Fig. 5.

[0084] The operation of the IABP balloon catheter 10 of this embodiment will be described below.

[0085] The IABP balloon catheter 10 of this embodiment comprises a catheter tube 30, a distal tip 20 attached to the distal end of the catheter tube 30, and a balloon 40 provided at the distal end of the catheter tube 30 and inflatable with a fluid supplied from the proximal side of the catheter tube 30. The balloon 40 is composed of a tubular balloon matrix 100, a proximal end 130 of the balloon matrix 100 is joined to the catheter tube 30, and a distal end 120 of the balloon matrix 100 is joined to the distal tip 20 or the catheter tube 30 in a state rotated circumferentially by a predetermined angle or more with respect to the proximal end 130 of the balloon matrix 100 attached to the catheter tube 30.

[0086] According to the above configuration, the balloon matrix 100 constituting the balloon 40 is attached to the distal end of the catheter tube 30 with the distal joint 42a rotated circumferentially by a predetermined angle or more relative to the proximal joint 43a. As a result, when the balloon 40 is inflated, the balloon 40 expands while rotating around its axis, and this rotation generates blood flow toward the distal side (coronary artery side). When the balloon 40 is deflated, the balloon 40 contracts while rotating around its axis, and this rotation generates blood flow toward the proximal side (descending thoracic aorta side). As a result, blood flow generation during IABP can be appropriately assisted, improving the cardiac function support effect of IABP.

[0087] In addition, in the IABP balloon catheter 10 of this embodiment, when the balloon 40 is inflated, the inflation / deflation section 41 located in the axial center of the balloon 40 may extend straight in the axial direction and expand so that its cross-sectional shape is uniform in the axial direction.

[0088] According to the above configuration, when IABP is performed, the balloon 40 can be inflated so as to appropriately compress the inner wall of the descending thoracic aorta.

[0089] Furthermore, according to the present embodiment, there is provided a method for manufacturing an IABP balloon catheter 10 having a balloon 40 that is inflatable by fluid supplied from the proximal side of the catheter tube 30 attached to the distal end of the catheter tube 30, the method comprising: rotating the cylindrically formed balloon matrix 100 so that the distal end 120 and the proximal end 130 of the balloon matrix 100 are twisted circumferentially by a predetermined angle or more; joining the proximal end 130 of the balloon matrix 100 to the catheter tube 30; and joining the proximal end 130 of the balloon matrix 100 to the distal tip 20 attached to the distal end of the catheter tube 30 or to the catheter tube 30. The IABP balloon catheter 10 of this embodiment can be manufactured by this method.

[0090] (Experimental example) An experiment conducted to confirm the function of the balloon 40 of the IABP balloon catheter 10 of this embodiment will be described below. This experiment was conducted under the environment shown in Fig. 7. Fig. 7 is a diagram illustrating an experimental system for confirming the function of the balloon 40 of the IABP balloon catheter 10 of this embodiment.

[0091] As shown in Figure 7, a circulation channel was created in which distilled water W placed in reservoir 1 was pumped up by pump 2 and circulated back to the reservoir. By pumping the distilled water W placed in reservoir 1 with pump 2 and flowing it through the circulation channel, a constant speed water flow was created in the circulation channel. Tracer particles Tr were added to the distilled water W, and the water flow in the circulation channel was visualized by observing the tracer particles Tr suspended in the distilled water W.

[0092] A balloon placement space S was provided in part of the circulation flow path, and the balloon of an IABP balloon catheter could be placed in this balloon placement space S. The balloon placement space S was composed of a tube with a diameter of 30 mm and a length of 34 mm, and the distal end of the balloon was placed facing upstream of the circulation flow path. In addition, an IABP driver 3 capable of supplying and discharging fluid to and from the balloon was connected to the IABP balloon catheter, so that the balloon could be inflated and deflated using the IABP driver 3.

[0093] Furthermore, a high-speed camera 4 was installed to capture images of the vicinity of the distal end of the balloon placed in the balloon placement space S.

[0094] In this experiment, the following three types of balloons were prepared as balloons for IABP balloon catheters. (1) Normal balloon (a balloon made by attaching the balloon base in a natural state without twisting) (2) 90° twisted balloon (a balloon fabricated by attaching the balloon base in a state where the distal end is rotated 90° circumferentially relative to the proximal end) (3) 360° twisted balloon (a balloon fabricated by attaching the balloon base in a state where the distal end is rotated 360° circumferentially relative to the proximal end) Note that (1) is a balloon according to the prior art, and (2) and (3) are balloons according to the present invention.

[0095] For each of the balloons (1) to (3) above, the balloon was expanded and contracted using the IABP drive device 3 while distilled water W was flowing through the circulation flow path at a constant rate, and the water flow near the distal end of the balloon was captured as a video using a high-speed camera 4.

[0096] The video images taken for each of the balloons (1) to (3) above were played back, and the movements of the tracer particles Tr when the balloons were expanded and contracted were visually observed.

[0097] For all of the balloons (1) to (3) above, it was confirmed that when the balloon was inflated, the tracer particles Tr moved in the direction toward the distal side of the balloon, i.e., in the opposite direction (reverse direction) to the water flow in the circulation channel. Furthermore, from the graph shown in Figure 8, it was confirmed that for all of the balloons (1) to (3) above, when the balloon was deflated, the tracer particles moved in the direction toward the proximal side of the balloon, i.e., in the same direction (forward direction) as the water flow in the circulation channel.

[0098] The video captured for each of the balloons (1) to (3) above was played back, and the movement (length) of 10 tracer particles Tr randomly selected from the many tracer particles Tr displayed was measured from the contracted state to the expanded state of the balloon, and the average value was calculated. The average movement (reverse direction) of the tracer particles Tr when each of the balloons (1) to (3) above was expanded is shown in Figure 8. In the graph shown in Figure 8, the average movement (reverse direction) of the tracer particles Tr when the balloon was expanded is plotted as a triangle.

[0099] The video captured for each of the balloons (1) to (3) above was played back, and the movement (length) of 10 tracer particles Tr randomly selected from the many tracer particles Tr displayed was measured from the expanded state to the contracted state of the balloon, and the average value was calculated. The average movement (forward direction) of the tracer particles Tr when each of the balloons (1) to (3) above was expanded is shown in Figure 8. In the graph shown in Figure 8, the average movement (forward direction) of the tracer particles Tr when the balloon was expanded is plotted as a square.

[0100] 8, it can be seen that the average movement amount (in the reverse direction) of the tracer particles Tr is larger in the twisted balloons (balloons according to the present invention) in the states (2) and (3) above than in the normal balloon (balloon according to the prior art) without twisting in the state (1) above. In other words, the balloon according to the present invention has a greater extrusion force for pushing out the liquid on the distal side of the balloon than the balloon according to the prior art, and can more effectively create blood flow toward the coronary arteries when the balloon is inflated, thereby increasing the amount of blood flowing into the coronary arteries.

[0101] When comparing the twisted balloons (2) and (3) above, it can be seen that the average movement (reverse direction) of the tracer particles Tr is greater in the balloon (3) fabricated with the balloon matrix attached at a 360° circumferential rotation than in the balloon (2) fabricated with the balloon matrix attached at a 90° circumferential rotation. In other words, increasing the circumferential rotation angle (twist angle) increases the extrusion force that pushes out the liquid on the distal side of the balloon, more effectively creating blood flow toward the coronary arteries during balloon inflation and increasing the amount of blood flowing into the coronary arteries.

[0102] 8, it can be seen that the average movement amount (forward direction) of the tracer particles Tr is greater in the twisted balloons (balloons according to the present invention) described in (2) and (3) above, compared to the normal balloon without twist (balloon according to the prior art) described in (1) above. In other words, the balloon according to the present invention has a greater retraction force for drawing in liquid on the distal side of the balloon than the balloon according to the prior art, and can more effectively create blood flow toward the descending thoracic aorta when the balloon is deflated, thereby increasing the amount of blood flowing from the heart to the descending thoracic aorta.

[0103] When comparing the twisted balloons (2) and (3) above, it can be seen that the average movement (forward direction) of the tracer particles Tr is greater in the balloon (3) fabricated with the balloon matrix attached at a 360° circumferential rotation than in the balloon (2) fabricated with the balloon matrix attached at a 90° circumferential rotation. In other words, increasing the circumferential rotation angle (twist angle) increases the force of attraction that draws in the liquid on the distal side of the balloon, more effectively creating blood flow toward the descending thoracic aorta when the balloon is deflated, thereby increasing the amount of blood flowing from the heart to the descending thoracic aorta.

[0104] The above-described embodiments are provided to facilitate understanding of the present invention and are not intended to limit the present invention. The components disclosed in the above-described embodiments are intended to encompass 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 encompassed by the present invention. [Explanation of symbols]

[0105] 1. Reservoir 2 pumps 3 IABP drive unit 4. High-speed camera 10, 200 IABP balloon catheter 20 Tip 21 Through hole 30 catheter tube 31 Inner tube 31L 1st lumen 32 Outer tube 32L second lumen 40, 240 balloons 41, 241 Expansion and contraction section 42, 242 Distal tapered section 42a, 242a distal junction 43, 243 Proximal tapered section 43a, 243a proximal junction 50 Branch 51 Outer tube fixing part 52 Main executives 53 Lateral branch 54 Outer tube insertion port 55 Fluid supply / discharge port 56 Blood pressure measurement port 100 balloon mother 110 Torso 120 distal end 130 proximal end M marker line Ma, Mb marker line ends S Balloon placement space Tr tracer particles W Distilled water

Claims

[Claim 1] A catheter tube; a distal tip attached to the distal end of the catheter tube; a balloon provided at the distal end of the catheter tube and expandable by a fluid supplied from the proximal side of the catheter tube; The balloon is composed of a balloon base body formed in a cylindrical shape, a proximal end of the balloon body joined to the catheter tube; a distal end of the balloon matrix attached to the catheter tube, the distal end of the balloon matrix being joined to the distal tip or the catheter tube in a state rotated by a predetermined angle in the circumferential direction relative to the proximal end of the balloon matrix attached to the catheter tube.

Images