Double-membrane balloon catheter

Abstract

The invention provides a balloon catheter with a single expansion cavity. The balloon catheter can prevent a balloon from being broken and improve contraction response. The inner balloon (3) and the inner tube (5) are bonded to each other and the outer balloon (2) and the inner balloon (3) are bonded to each other in the tip-side bonding section (12a). Furthermore, in the base-end-side adhesive section (12b), the inner balloon (3) is adhered to the outer tube (4), and the outer balloon (2) is adhered to the inner balloon (3), thereby forming a balloon catheter having a single dilation lumen (8). In the expansion part (11), the outer balloon (2) and the inner balloon (3) are not adhered to each other. The maximum diameter ([phi] 2) of the inner balloon (3) is set to be smaller than the maximum diameter ([phi] 1) of the outer balloon (2). In addition, the length (L2) of the inner balloon (3) in the expansion part (11) is set to be shorter than the length (L1) of the outer balloon (2).

Description

Technical Field

[0001] This invention relates to a balloon catheter, and more particularly to a balloon catheter for treating aortic stenosis. Background Technology

[0002] For patients with severe aortic stenosis who are difficult to treat surgically or undergo transcatheter aortic valve implantation (TAVI) / transcatheter aortic valve replacement (TAVR), balloon aortic valve repair (BAV) is used. However, current BAV procedures require high-velocity pacing to reduce cardiac output and prevent serious complications caused by balloon displacement during dilation. However, some patients cannot tolerate high-velocity pacing, and frequent high-velocity pacing can worsen prognosis. Therefore, there is an urgent need for a technique that allows for frequent dilation without high-velocity pacing.

[0003] Aortic valve expansion (BAV) using a drive system synchronized with an electrocardiogram (ECG) (hereinafter also referred to as "ECG-synchronized BAV" or "ECG-synchronized aortic valve dilation system") can dilate the aortic valve according to physiological rhythm. Therefore, frequent dilation can be performed without high-frequency pacing, thus providing this treatment option for patients who cannot undergo conventional aortic valve dilation. Furthermore, this system offers a significantly improved therapeutic effect compared to existing aortic valve balloons.

[0004] ECG-synchronized BAV, by frequently (at least 6 times) dilating the aortic valve with a balloon, significantly increases the valve orifice area compared to the traditional method that requires 1 to 3 dilations, and therefore has the potential to save patients whose lives could not be saved until now (see Non-Patent Literature 1).

[0005] The most serious complication of synchronized BAV on ECG is air embolism (cerebral infarction) caused by balloon rupture. To make synchronized BAV on ECG practical, this risk must be reduced to as close to zero as possible.

[0006] As a technique to prevent balloon rupture, the inventors have proposed a balloon catheter consisting of a shaft, an inner balloon, and an outer balloon (see Patent Document 1). This catheter covers the inner balloon with the outer balloon, and both the front and rear ends of the catheter are mounted on the shaft. The radial elongation of the outer balloon is smaller than that of the inner balloon, thereby preventing over-inflation of the outer balloon and avoiding the risk of balloon rupture, thus making treatment safer.

[0007] However, in the balloon catheter of Patent Document 1, the shaft has an inner balloon connecting lumen that communicates with the interior of the inner balloon through the end face of the rear end side in the length direction, and an outer balloon connecting lumen that communicates with the interior of the outer balloon. This technology does not involve a balloon catheter with a single dilatation lumen.

[0008] In balloon catheters with a single expansion lumen, as a technique for making the balloon double-layered, there are balloon catheters with inner and outer inflatable balloons coupled to the catheter axis, wherein the inner balloon is less elastic than the outer balloon (see Patent Document 2).

[0009] However, the balloon catheter in Patent Document 2 is a technology based on cryoballoons. Therefore, when this technology is applied to BAV, the inner balloon has less elasticity than the outer balloon, resulting in insufficient strength and easy rupture of the outer balloon.

[0010] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2011-152181

[0012] [Patent Document 2] Japanese Patent No. 7018501

[0013] [Non-patent literature]

[0014] [Non-Patent Literature 1] Konishi A, "The effect of multiple-inflation balloonaortic valvuloplasty", Heart and Vessels 2020, 35, 1557-1562 Summary of the Invention

[0015] The technical problem that the invention aims to solve

[0016] Therefore, in ECG-synchronized BAV, it is necessary to reduce the risk of air embolism due to balloon rupture to near zero. On the other hand, rapid balloon inflatation and deflation are required in BAV, and the balloon's contraction response capability also needs to be improved.

[0017] In view of this situation, the object of the present invention is to provide a balloon catheter with a single dilatation lumen that can prevent balloon rupture and improve contraction response.

[0018] To address the aforementioned problems, the present invention provides a double-membrane balloon catheter having a single expansion lumen within a double-membrane balloon. The double-membrane balloon comprises an outer balloon and an inner balloon. The proximal end of the outer balloon is bonded to the proximal end of the inner balloon, and the distal end of the outer balloon is bonded to the distal end of the inner balloon. When the double-membrane balloon expands, the inner surface of the expansion portion of the outer balloon is not bonded to the outer surface of the expansion portion of the inner balloon. The inner diameter of the outer balloon is larger than the outer diameter of the inner balloon.

[0019] By designing the membrane as a double-layered structure with an outer and an inner balloon, even if holes appear on the balloon surface, fluids such as air will not leak into the bloodstream. Furthermore, because the outer and inner balloons are not bonded together at the expansion portion, they do not form a single unit, thus offering the advantage that the inner balloon will not be affected if the outer balloon is damaged.

[0020] In addition, since the diameters of the lateral and medial balloons are not the same, with the inner diameter of the lateral balloon being larger than that of the medial balloon, the contractile force of the medial balloon is increased during the contraction phase after balloon inflation, resulting in a balloon with good contractile response.

[0021] In the dual-membrane balloon catheter of the present invention, the axial length of the outer balloon is preferably longer than that of the inner balloon. Regarding the dimensions of the outer and inner balloons, this includes not only their diameters but also their lengths. By increasing the axial length of the outer balloon and shortening the axial length of the inner balloon, the contraction response can be improved.

[0022] In the dual-membrane balloon catheter of the present invention, the outer balloon is preferably made of a material with a higher hardness than the inner balloon. By using a material that is harder than the inner balloon to construct the outer balloon, rupture of the outer balloon can be effectively prevented. Specifically, as the material of the outer balloon, polyether block amide or polyamide, polyurethane, polyethylene or mixtures thereof are preferably used; as the material of the inner balloon, polyurethane or a mixture of polyurethane and polyamide or polyether block amide is preferably used.

[0023] In the dual-membrane balloon catheter of the present invention, the lateral balloon and the inner balloon can have different cross-sectional shapes in part or all of the longitudinal region. Because the lateral balloon is pressed against the inner balloon by external pressure (atmospheric pressure or intracardiac blood pressure), the lateral and inner balloons each exhibit different shapes. Therefore, if the lateral balloon is made of a rigid material, it follows the shape of the inner balloon during expansion and eventually stabilizes in the shape of the lateral balloon. Here, the cross-sectional shape, for example, when the lateral balloon is nearly cylindrical, the inner balloon will also be nearly cylindrical at the end of expansion.

[0024] Because the fixation force of the balloon catheter tends to decrease during balloon contraction, it is necessary to prevent the balloon from shifting its fixed position as it transitions from the contraction to the expansion phase. For example, by designing the outer balloon as an ellipse or cylinder and the inner balloon as an hourglass, dumbbell, or triangular prism polygon, the outer balloon will expand following the shape of the inner balloon during the initial to mid-expansion phases, thereby strengthening the fixation on the affected area.

[0025] Furthermore, during the mid-to-late stage of expansion (maximum expansion), the lateral balloon is already in contact with the affected area and is less prone to slippage. Therefore, effective expansion of the affected area is more important than enhanced fixation. Because the lateral balloon is made of a material with higher rigidity than the medial balloon, the medial balloon will expand to conform to the shape of the lateral balloon during this stage. In this way, the affected area can be firmly fixed while effectively expanding.

[0026] In the dual-membrane balloon catheter of the present invention, before assembly, the ratio of the outer diameter of the inner balloon to the inner diameter of the outer balloon is 70% to 90%, and the ratio of the axial length of the inner balloon to the axial length of the outer balloon is 75% to 90%. In this case, the gap between the inner surface of the outer balloon dilation portion and the outer surface of the inner balloon dilation portion can be filled with less than 0.1 mL of gas. By setting the amount of gas filling the space between the balloons within this range, the risk of balloon rupture can be reduced and the contraction response improved.

[0027] The aortic valve dilation system of the present invention comprises any of the aforementioned double-membrane balloon catheters and a drive unit. This drive unit synchronously expels and draws in gas into the dilation lumen of the double-membrane balloon catheter in sync with the electrocardiogram (ECG), thereby causing the dilation lumen to automatically and repeatedly contract and dilate in sync with the ECG. Because the drive unit synchronously expels and draws in gas into the dilation lumen of the double-membrane balloon catheter in sync with the ECG, high-frequency pulsation is not required, allowing for multiple dilations and enabling treatment of patients who were previously untreatable. Furthermore, the use of a double-membrane balloon catheter reduces the risk of balloon rupture while improving contraction response, resulting in a system with high safety and effectiveness.

[0028] Invention Effects

[0029] The double-membrane balloon catheter of the present invention has a single dilatation lumen, which can prevent balloon rupture and improve the effect of contraction response. Attached Figure Description

[0030] Figure 1 This is a cross-sectional view of the double-membrane balloon catheter of Example 1;

[0031] Figure 2 This is an explanatory diagram of the double-membrane balloon catheter of Example 1;

[0032] Figure 3 This is a schematic diagram of the contraction of the double-membrane balloon catheter in Example 1;

[0033] Figure 4 This is a functional block diagram of the aortic valve dilation system in Example 1;

[0034] Figure 5 This is a schematic diagram of the use of the double-membrane balloon catheter in Example 1;

[0035] Figure 6This is an explanatory diagram of the gas measurement experiment between the inner and outer balloons;

[0036] Figure 7 This is a schematic diagram of the contraction of a comparative example balloon catheter. Detailed Implementation

[0037] Hereinafter, an example of an embodiment of the present invention will be described with reference to the accompanying drawings. Furthermore, the scope of the present invention is not limited to the following embodiments and examples, and other modifications and changes are possible.

[0038]

Example 1

[0039] Figure 1 This is a cross-sectional view of the double-membrane balloon catheter of Example 1. Figure 1 As shown, the double-membrane balloon catheter 1 consists of an outer balloon 2, an inner balloon 3, an outer tube 4, an inner tube 5, and a holding part 6. The inner tube 5 is inserted into the outer tube 4, forming a lumen 7a between the outer tube 4 and the inner tube 5. Additionally, a lumen 7b is formed within the inner tube 5 to accommodate the guidewire 14 (see reference). Figure 5 () can be inserted into it.

[0040] An outer balloon 2 and an inner balloon 3 are provided at the front end of the outer tube 4 and the inner tube 5, and a holding part 6 is provided at the base end of the outer tube 4 and the inner tube 5. A through hole 61 communicating with the lumen 7a is provided on the holding part 6, and carbon dioxide gas is filled / discharged into the expansion chamber 8 through the through hole 61 and the lumen 7a.

[0041] Figure 2 This is an explanatory diagram of the double-membrane balloon catheter of Example 1. (As shown...) Figure 2 As shown, at the adhesive portion 12a on the anterior side, the inner balloon 3 is adhered to the inner tube 5, and the outer balloon 2 is adhered to the inner balloon 3. At the adhesive portion 12b on the basal side, the inner balloon 3 is adhered to the outer tube 4, and the outer balloon 2 is adhered to the inner balloon 3. Thus, the double-membrane balloon catheter 1 is a balloon catheter with a single dilation lumen 8. In addition, the outer balloon 2 and the inner balloon 3 are not adhered at the dilation portion 11.

[0042] The reinforcing part 51 is used to locally reinforce the inner tube 5 located at the expansion part 11 and to prevent the inner tube from bending due to the compressive force generated by the deformation of the balloon during balloon expansion. In addition, the reinforcing part 51 is provided with markings (not shown) for easy identification under X-ray fluoroscopy.

[0043] The outer balloon 2 is made of polyether block amide. The inner balloon 3 is made of polyurethane.

[0044] The outer balloon 2 is made of a material with a hardness higher than that of the inner balloon 3. The hardness of the outer balloon 2 is 72D, and the hardness of the inner balloon 3 is 80A.

[0045] The lateral sac 2 is elliptical in shape, but is not limited to this shape; it can also be polygonal, such as roughly triangular prism. Figure 2 As shown, the medial balloon 3 differs from the lateral balloon 2 in that it has an hourglass shape with a concave central portion along its length. This hourglass shape enhances the fixation force on the heart valves. In contrast, the medial balloon 3 can have, for example, an elliptical shape without a central concavity in the longitudinal direction.

[0046] The maximum outer diameter φ2 of the inner balloon 3 is smaller than the maximum inner diameter φ1 of the outer balloon 2. Furthermore, the length L2 of the inner balloon 3 in the expansion section 11 is shorter than the length L1 of the outer balloon 2. The advantage of intentionally designing the inner balloon 3 to have a smaller diameter and length is that, after balloon inflation, the material's action generates a balloon contraction force, thereby increasing the balloon's contraction speed.

[0047] Here, the bonding structure of the outer balloon 2 and the inner balloon 3 will be described. During the manufacturing stage, the outer balloon 2 and the inner balloon 3 are placed on the core (not shown) in the order of inner balloon 3 and outer balloon 2. Then, the bonding parts (12a, 12b) at both ends are bonded together. Finally, the core is removed. Therefore, the air between the outer balloon 2 and the inner balloon 3 is extracted, but it does not become a vacuum, and a gap 9 is formed between the outer balloon 2 and the inner balloon 3.

[0048] Here, the amount of gas present in gap 9 will be explained. The dimensions of the outer balloon 2 and inner balloon 3 before assembly into the outer tube 4 and inner tube 5 are preferably as follows: the inner diameter of the outer balloon 2 is 15–30 mm, the outer diameter of the inner balloon 3 is 10.5–27 mm, the axial length of the outer balloon 2 is 30–50 mm, the axial length of the inner balloon is 22.5–45 mm, the ratio of the outer diameter of the inner balloon 3 to the inner diameter of the outer balloon 2 is 70% or more and 90% or less, and the ratio of the axial length of the inner balloon 3 to the axial length of the outer balloon 2 is 75% or more and 90% or less. In this embodiment, the dimensions of the outer balloon 2 and inner balloon 3 before assembly into the outer tube 4 and inner tube 5 are: the inner diameter of the outer balloon 2 is 20 mm, the outer diameter of the inner balloon 3 is 14 mm, the axial length of the outer balloon 2 is 40 mm, and the axial length of the inner balloon is 30 mm. Furthermore, the dimensions of the lateral balloon 2 and the medial balloon 3 disclosed herein do not include the adhesive portions 12a and 12b.

[0049] Under these conditions, a test was conducted to measure the amount of gas present between the outer balloon 2 and the inner balloon 3.

[0050] Figure 6 This is an explanatory diagram of the gas measurement experiment between the inner and outer balloons. For ease of explanation, Figure 6The double-membrane balloon catheter 1 is not shown in detail. (For example...) Figure 6 As shown, firstly, water 16 is filled into water tank 15, immersing beaker 17 in water tank 15 in a non-air-containing state. The expansion lumen 8 of the double-membrane balloon catheter 1 is filled with water. In this state, the double-membrane balloon catheter 1 is immersed in water tank 15, and beaker 17 covers the areas of the outer balloon 2 and inner balloon 3. A needle 18 is inserted into the outer balloon 2 and inner balloon 3 to form a hole. Then, the outer balloon 2 is pressed, squeezing out the gas 7 in the gap 9 and storing it in beaker 17. Subsequently, the gas is collected using a 1mL syringe 19 and its volume is measured. The results show that the collected gas volume is less than 0.1mL.

[0051] As can be seen from the above, the gap between the inner surface of the expansion portion 11 of the outer balloon 2 and the outer surface of the expansion portion 11 of the inner balloon 3 is filled with less than 0.1 mL of gas.

[0052] As described above, since the inner balloon 3 is made with a smaller diameter than the outer balloon 2, it covers the core under tension when mounted on the core. This improves the contraction response of the balloon during contraction. Furthermore, since the outer balloon 2 is pressed against the inner balloon 3 by external pressure, when the outer balloon 2 is made of a rigid material, it will follow the shape of the inner balloon 3 during expansion and eventually stabilize within the shape of the outer balloon 2.

[0053] Since the outer balloon 2 and the inner balloon 3 are not bonded at the expansion portion 11, the balloons will not become a single unit. The advantage is that if the outer balloon 2 is damaged, the inner balloon 3 will not be involved in the damage.

[0054] Figure 3 This is a schematic diagram of the contraction of the double-membrane balloon catheter in Example 1. (1) shows the state of folding of the outer balloon, and (2) shows the state of folding of the inner balloon. Additionally, Figure 7 A schematic diagram showing the contraction of the balloon catheter in the comparative example. Additionally, in Figure 3 The illustration of the reinforcing part 51 is omitted in the text.

[0055] Figure 7 In the comparative example balloon catheter shown, the outer balloon 2 and the inner balloon 3 are bonded together on almost the entire surface of the dilation portion 11a. Therefore, when the balloon contracts, as... Figure 7 As shown in region P3, the integrated lateral balloon 2 and medial balloon 3 will bend simultaneously at the same location. Due to the greater thickness of the integrated lateral balloon 2 and medial balloon 3, the anterior part of the balloon is more susceptible to damage. Furthermore, if the lateral balloon 2 is damaged, the medial balloon 3 may also be affected.

[0056] In contrast, in the balloon catheter 1 of Embodiment 1, since the dilation portion 11 is in a contracted state, therefore, as Figure 3 As shown in (1), even if the lateral balloon 2 folds at region P1, the medial balloon 3 may not necessarily fold as well. Furthermore, as... Figure 3 As shown in (2), even if the inner balloon 3 has a fold at region P2, the outer balloon 2 may not also have a fold.

[0057] Therefore, even if folds appear in the lateral balloon 2 or the medial balloon 3, there is an advantage that the balloon thickness will not place a load on the top of the folds. In addition, since the lateral balloon 2 and the medial balloon 3 are not integrally formed, folds will be generated separately when the balloons contract, thus reducing the risk that damage to one balloon may simultaneously affect the other balloon.

[0058] In this way, since the outer balloon 2 and the inner balloon 3 are not bonded at the expansion portion 11, not only can the rupture of each balloon be prevented, but the simultaneous rupture of both balloons can also be effectively prevented.

[0059] Figure 4 A functional block diagram of the aortic valve dilation system of Embodiment 1 is shown. Figure 4 As shown, the aortic valve dilation system 10 consists of a double-membrane balloon catheter 1 and a drive unit 13. The dilation chamber 8 automatically and repeatedly contracts and dilates in sync with the electrocardiogram (ECG). The drive unit 13, synchronized with the ECG, expels and inhales carbon dioxide gas 7 into the dilation chamber 8 of the double-membrane balloon catheter 1. Here, the drive unit 13 is connected to an ECG data acquisition unit (not shown) and an ECG synchronization calculation unit. The ECG data acquisition unit acquires the patient's ECG data, and the ECG synchronization calculation unit calculates data for ECG synchronization based on the ECG data acquired by the ECG data acquisition unit. The drive unit 13 is driven synchronously with the ECG based on the calculated data for ECG synchronization.

[0060] Figure 5 This is a schematic diagram illustrating the use of the double-membrane balloon catheter in Example 1. Figure 5 As shown, the double-membrane balloon catheter 1 inserts a guidewire 14 from the ascending aorta 21 of the heart 20 into the left ventricle 23, and guides the dilator 11 to the position of the aortic valve 22, where it dilates and contracts.

[0061] The aortic valve dilation system 10, because it does not require high-frequency pacing and can dilate frequently, can not only treat patients who were previously untreatable, but also has advantages such as effectiveness, safety and ease of operation.

[0062] Using the aortic valve dilation system 10 of this embodiment, 500 dilations were performed in a non-clinical trial environment simulating human subjects. Neither the lateral balloon 2 nor the medial balloon 3 ruptured, confirming the effectiveness of the system, including reducing the aortic valve pressure gradient.

[0063] Industrial application

[0064] This invention is useful as a balloon catheter for treating heart disease and other conditions.

[0065] Explanation of symbols in the diagram

[0066] 1. Double-membrane balloon catheter; 2. Lateral balloon; 3. Medial balloon; 4. Outer tube; 5. Inner tube; 6. Handling part;

[0067] 7. Carbon dioxide gas; 7a, 7b. Lumens; 8. Dilation lumen; 9. Interval; 10. Aortic valve dilation system;

[0068] 11, 11a Expansion section; 12a, 12b Adhesion section; 13 Drive section; 14 Guide wire; 15 Water tank; 16 Water;

[0069] 17 Beaker; 18 Needle; 19 Syringe; 20 Heart; 21 Aorta; 22 Aortic valve;

[0070] 23 Left ventricle; 51 Reinforcing part; 61 Through hole; L1, L2 length; P1~P3 location; φ1, φ2 diameter.

Claims

1. A double-membrane balloon catheter, wherein the balloon catheter has a single dilatation lumen within a double-membrane balloon, wherein, The dual-membrane balloon includes an outer balloon and an inner balloon. The lateral balloon and the medial balloon are bonded at their proximal ends to each other and at their distal ends. When the double-membrane balloon inflates, it expands, and the inner surface of the expansion portion of the outer balloon and the outer surface of the expansion portion of the inner balloon do not adhere to each other. Furthermore, the inner diameter of the outer balloon is larger than the outer diameter of the inner balloon.

2. The double-membrane balloon catheter according to claim 1, wherein, The axial length of the outer balloon is longer than that of the inner balloon.

3. The double-membrane balloon catheter according to claim 1, wherein, The outer balloon is made of a material with a higher hardness than the inner balloon.

4. The double-membrane balloon catheter according to claim 3, wherein, The outer balloon and the inner balloon may have different cross-sectional shapes in some or all of their longitudinal regions.

5. The double-membrane balloon catheter according to claim 2, wherein, Before assembly into a catheter, when the ratio of the outer diameter of the inner balloon to the inner diameter of the outer balloon is 70% to 90%, and the ratio of the axial length of the inner balloon to the axial length of the outer balloon is 75% to 90%, The gap between the inner surface of the expansion portion of the outer balloon and the outer surface of the expansion portion of the inner balloon is filled with less than 0.1 mL of gas.

6. An aortic valve dilation system, comprising: The double-membrane balloon catheter according to any one of claims 1 to 5; and A drive section for discharging and filling gas into the dilation lumen of the double-membrane balloon catheter in sync with an electrocardiogram; The expansion chamber automatically and repeatedly contracts and expands in sync with the electrocardiogram.

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