A balloon dilatation catheter

Abstract

The present invention discloses a balloon dilatation catheter, which belongs to the technical field of interventional treatment instruments, and comprises: a catheter; a balloon connected to the outer periphery of the distal end of the catheter, and having a fully filled state and a recovered folded state folded and wound around the circumference of the catheter; the balloon comprises an expansion portion and a connecting portion located at both axial ends of the expansion portion; an elastic support member located inside the balloon, and comprising a fixing ring fixed to the outer periphery of the catheter, and an elastic rod connected to the outer periphery of the fixing ring; the elastic rod has a bending elastic state of bending deformation around the circumference of the catheter; an elastic member fixed to the outside of the connecting portion and having an elastic stretching state of being stretched and deformed. When the balloon is depressurized and retracted, the balloon retracts and the multiple elastic rods form a plurality of folding wings, and the multiple folding wings form a winding state around the catheter under the action of the elastic force released by the multiple elastic members, so that the overall diameter of the balloon after contraction is smaller, which is conducive to withdrawing the balloon from the blood vessel and avoiding damage to the blood vessel during the withdrawal process of the balloon.

Description

Technical Field

[0001] The present invention relates to the technical field of interventional medical devices, and in particular to a balloon dilatation catheter. Background Art

[0002] The balloon dilatation catheter usually includes a long catheter and an expandable balloon at the distal end of the catheter. The balloon expands after reaching the target location of the blood vessel, which can dilate the narrow part of the blood vessel. After the balloon is expanded, the pressure needs to be released to shrink it, and then it is withdrawn out of the body.

[0003] In the prior art, the shape of the balloon after depressurization is irregular. After depressurization, the balloon usually presents a two-piece fitting structure attached to the surface of the catheter. This structure makes the overall outer diameter of the balloon after depressurization relatively large, which can easily cause damage to the blood vessel wall and is not conducive to the withdrawal of the balloon from the body.

[0004] Therefore, how to reduce the overall outer diameter of the balloon when it is deflated and contracted is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] In view of this, the present invention provides a balloon dilatation catheter to solve the defect that the balloon of the existing balloon dilatation catheter has a large overall outer diameter after decompression and contraction, which is not conducive to the withdrawal of the balloon from the body, thereby providing a balloon dilatation catheter.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] A balloon dilatation catheter, comprising:

[0008] catheter;

[0009] The balloon is connected to the outer periphery of the distal end of the catheter, and has a fully filled state in which the balloon expands outward after the inner cavity is filled, and a recovered folded state in which the balloon is folded and rolled around the circumference of the catheter after the inner cavity is depressurized; the balloon comprises an expansion portion and connecting portions located at both axial ends of the expansion portion, and the connecting portions are connected between the expansion portion and the catheter;

[0010] An elastic support member is located inside the balloon, and includes a fixing ring fixed to the outer periphery of the catheter, and a plurality of elastic rods connected to the outer periphery of the fixing ring and made of elastic material; the elastic rods have an upright state without elastic deformation and a bent elastic state with bending deformation around the circumference of the catheter;

[0011] An elastic member, both ends of which are fixed outside the connecting portion and have an elastic stretching function;

[0012] When the balloon expands outward, the elastic member is stretched along with the expansion of the balloon, and the elastic rod recovers from the bent elastic state to the upright state;

[0013] When the balloon is depressurized and retracted, the balloon retracts outside the multiple elastic rods in an upright state and combines with the multiple elastic rods to form a multiple folding wings. The elastic member is shortened and stretched as the balloon retracts, and the multiple folding wings are bent and deformed in the same direction around the circumference of the catheter under the action of the elastic force generated in the process of shortening and stretching the elastic member.

[0014] Furthermore, the stretching direction of the elastic member does not intersect with the central axis of the catheter.

[0015] Furthermore, the elastic member is an elastic pull wire that can be stretched and contracted in length, one end of the elastic pull wire is fixed to an end where the connecting portion is connected to the catheter, and the other end of the elastic pull wire is fixed to an end where the connecting portion is connected to the expansion portion.

[0016] Furthermore, when the balloon is in the fully filled state, the truncated cone-shaped portions at both axial ends of the balloon are the connecting portions, and the length of the elastic pull line after being stretched is greater than the generatrix length of the truncated cone-shaped connecting portion.

[0017] Furthermore, the number of the elastic members is three or more, and the three or more elastic members are evenly arranged along the conical surface of the truncated cone-shaped connecting portion.

[0018] Furthermore, when the balloon is in the fully filled state, the elastic rod is in an upright state without elastic deformation, and an end of the elastic rod away from the fixing ring is spaced from the inner wall of the balloon.

[0019] Furthermore, three or more elastic rods are evenly arranged around the circumference of the fixing ring.

[0020] Furthermore, a portion of the catheter located inside the balloon is sleeved with a developing ring for indicating the position of the balloon, the developing ring is provided with a groove, and the elastic rod is inserted into the groove along the axial direction of the developing ring.

[0021] Furthermore, there are two developing rings and two elastic supporting members, the two developing rings correspond to two axial ends of the expansion portion respectively, and each developing ring is connected to one elastic supporting member.

[0022] Furthermore, the material of the balloon is any one or more of polyvinyl chloride, polyethylene, polyurethane, polyamide, polyether block polyamide, and polyethylene terephthalate.

[0023] The technical solution of the present invention has the following advantages: by arranging a plurality of elastic rods inside the balloon that can be circumferentially bent and deformed relative to the catheter, and arranging an elastic member that can be stretched and deformed outside the connecting portion of the balloon; when the balloon is depressurized and retracted, the balloon first retracts outside the plurality of elastic rods and combines with the plurality of elastic rods to form a plurality of folding wings, and the plurality of folding wings are bent and deformed in the same direction around the circumference of the catheter under the action of the elastic force released by the elastic member, and the plurality of folding wings are coiled around the catheter, so that the overall diameter of the balloon after contraction is smaller, which is conducive to withdrawing the balloon from the blood vessel and avoiding damage to the blood vessel during the withdrawal process of the balloon. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the balloon on the balloon dilatation catheter in an embodiment of the present invention when the balloon is in a fully filled state;

[0026] Figure 2 for Figure 1 Left view of

[0027] Figure 3 for Figure 2 Sectional view of the AA plane;

[0028] Figure 4 for Figure 1 A front view of

[0029] Figure 5 for Figure 4 Sectional view of the middle BB plane;

[0030] Figure 6 It is a schematic diagram of the three-dimensional structure of the balloon on the balloon dilatation catheter in the embodiment of the present invention when the balloon is in a contracted state;

[0031] Figure 7 for Figure 6 A front view of

[0032] Figure 8 for Figure 7 Sectional view of the middle CC plane;

[0033] Fig. 9 for Figure 6 Left view of

[0034] Fig.10 for Fig. 9Sectional view of the middle DD plane;

[0035] Fig.11 It is a schematic diagram of the three-dimensional structure of the balloon on the balloon dilatation catheter in the embodiment of the present invention when it is in a retracted and folded state;

[0036] Fig.12 for Fig.11 A front view of

[0037] Fig.13 for Fig.12 Sectional view of the middle EE plane;

[0038] Fig.14 for Fig.11 Left view of

[0039] Fig.15 Schematic diagram of the connection structure between the elastic support member and the developing ring in an embodiment of the present invention, wherein the elastic rod of the elastic support member is in an upright state;

[0040] Fig.16 for Fig.15 A front view of

[0041] Fig.17 for Fig.16 Sectional view of the FF plane;

[0042] Fig.18 Schematic diagram of the connection structure between the elastic support member and the developing ring in an embodiment of the present invention, wherein the elastic rod of the elastic support member is in an elastically stretched state;

[0043] Fig.19 for Fig.18 A front view of

[0044] Fig. 20 for Fig.19 Sectional view of the GG plane.

[0045] Explanation of the reference numerals: 1. catheter; 2. balloon; 21. expansion part; 22. connection part; 3. elastic support member; 31. fixing ring; 32. elastic rod; 4. elastic member; 5. folding wing; 6. developing ring; 7. catheter seat; 71. balloon filling interface; 72. guide wire interface. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of this application, it should be understood that the terms "proximal end" and "distal end" used throughout the text refer to near and far relative to the operator. When the present invention is used, the end close to the doctor or operator is the "proximal end", that is, the end where the operator is located, and the end away from the doctor or operator is the "distal end", that is, the end where the balloon is located. The above-mentioned description of the orientation is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0048] like Figure 1 A balloon dilatation catheter shown includes a catheter 1, a balloon 2 and a catheter seat 7; the balloon 2 is connected to the outer periphery of the distal end of the catheter 1, and the catheter seat 7 is connected to the proximal end of the catheter 1. The catheter seat 7 is provided with a guidewire interface 72 and a balloon filling interface 71; the catheter 1 has a guidewire cavity and a balloon filling cavity. When in use, the guidewire enters along the distal end of the catheter 1, passes through the guidewire cavity and exits from the guidewire interface 72, and the guidewire is used to transport the balloon dilatation catheter to the lesion site. The balloon 2 is connected to the balloon filling cavity, and the balloon filling cavity is connected to the balloon filling interface 71.

[0049] In this embodiment, the balloon 2 has a fully filled state in which it expands outward after its inner cavity is filled, a contracted state in which it retracts inward to form a plurality of folding wings 5 ​​after its inner cavity is depressurized, and a recovered folded state in which a plurality of folding wings 5 ​​are folded and rolled in the same direction around the circumference of the catheter 1. Figure 1-Figure 5 is a schematic diagram of the balloon 2 being in a fully inflated state, Figure 6-Figure 10 is a schematic diagram of the balloon 2 in a contracted state, Figure 11-Figure 14 It is a schematic diagram of the balloon 2 in a retracted folded state. It should be noted that the contracted state of the balloon 2 is only an intermediate state that may occur during the decompression and retraction process of the balloon 2. During the decompression and retraction process of the balloon 2, the process of the balloon 2 forming a plurality of folding wings 5 ​​and the process of the plurality of folding wings 5 ​​being wound in the same direction around the circumference of the catheter 1 can be performed separately or simultaneously.

[0050] In some embodiments, Figure 4 As shown, the balloon 2 includes an expansion portion 21 and connecting portions 22 located at both axial ends of the expansion portion 21, the connecting portion 22 is connected between the expansion portion 21 and the catheter 1, and the expansion portion 21 and the connecting portions 22 at both ends are an integrated structure. When the balloon 2 is in a fully filled state, the cylindrical portion in the middle of the balloon 2 is the expansion portion 21, and the truncated cone-shaped portions at both axial ends of the balloon 2 are the connecting portions 22. In other alternative embodiments, the shape of the connecting portion 22 after the balloon 2 is expanded is not limited to a truncated cone, but can also be a paraboloid of revolution.

[0051] In this embodiment, if Figure 2 and Figure 3As shown, the balloon dilatation catheter further includes an elastic support member 3 and an elastic member 4; wherein the elastic support member 3 is located inside the balloon 2, the elastic member 4 is fixed outside the two connecting parts 22, and the two ends of the elastic member 4 are fixed outside the connecting part 22, and the middle part of the elastic member 4 is not connected to the connecting part 22. Figure 4 , Figure 6 , Fig. 9 and Fig.14 As shown, the elastic member 4 has an unstretched initial state and a stretched elastic state; when the balloon 2 is in a fully filled state, the elastic member 4 is in a stretched elastic state. Figure 5 , Fig.13 , Fig.15 and Fig.18 As shown, the elastic support member 3 includes a fixing ring 31 fixed on the outer periphery of the catheter 1, and a plurality of elastic rods 32 connected to the outer periphery of the fixing ring 31 and made of elastic material; the elastic rods 32 have an upright state without elastic deformation and a bent elastic state in which bending deformation occurs around the circumference of the catheter 1.

[0052] In some embodiments, Figure 5 , Fig.15 and Fig.18 As shown, three elastic rods 32 are evenly arranged around the circumference of the fixing ring 31, and the three elastic rods 32 are bent in the same direction around the circumference of the catheter 1 when bent and deformed; for example, the three elastic rods 32 are all bent in the clockwise direction around the circumference of the catheter 1, or the three elastic rods 32 are all bent in the counterclockwise direction around the circumference of the catheter 1. In other alternative embodiments, the number of elastic rods 32 can also be more than three, and the more than three elastic rods 32 are evenly spaced around the circumference of the fixing ring 31.

[0053] In some embodiments, Figure 5 , Fig.15 and Fig.18 As shown, the elastic rod 32 is in the form of a thin sheet, and the elastic rod 32 can be elastically bent and deformed along its thickness direction after being subjected to force. When the elastic rod 32 is in an upright state without elastic bending and deformation, the length direction of the elastic rod 32 is arranged to extend outwardly along the radial direction of the fixing ring 31, and the width direction of the elastic rod 32 is arranged along the axial direction of the catheter 1. When the balloon 2 is in a fully filled state, there is a gap between the end of the elastic rod 32 away from the fixing ring 31 and the inner wall of the balloon 2. When the elastic rod 32 is bent and deformed, the end of the elastic rod 32 away from the fixing ring 31 is bent around the circumference of the catheter 1, and at this time, the distance between the end of the elastic rod 32 away from the fixing ring 31 and the central axis of the catheter 1 is shortened, thereby reducing the outer diameter of the balloon 2 after recovery and folding. In order to avoid scratches on the inner wall of the balloon 2 caused by the end of the elastic rod 32 away from the fixing ring 31, a circular arc transition surface is provided at the end of the elastic rod 32 away from the fixing ring 31.

[0054] In this embodiment, if Figure 2 , Figure 4 , Figure 6 , Fig. 9 and Fig.14 As shown, the elastic member 4 has an elastic stretching function. When the balloon 2 is in a fully filled state, the elastic member 4 is in an elastic stretching state in which it is stretched and lengthened; when the balloon 2 is in a recovered and folded state, the elastic member 4 restores the length of the initial state. When the elastic member 4 is restored from the elastic stretching state to the initial state, the elastic force released by the elastic member 4 is greater than the minimum elastic force required for the multiple elastic rods 32 to bend and deform.

[0055] In some embodiments, Figure 2 As shown, the number of elastic members 4 is three, and the three elastic members 4 are evenly arranged along the conical surface of the truncated cone-shaped connecting portion 22. In other alternative embodiments, the number of elastic members 4 can also be more than three, and the more than three elastic members 4 are evenly arranged along the conical surface of the truncated cone-shaped connecting portion 22.

[0056] In some embodiments, Figure 1 , Figure 2 and Figure 6 As shown, the length of the elastic member 4 in the elastic stretching state is greater than the generatrix length of the truncated cone-shaped connecting portion 22; the elastic member 4 can be in a straight line or a spiral curve shape. The stretching direction of the elastic member 4 does not intersect with the central axis of the catheter 1, for example, the stretching direction of the elastic member 4 is tangent to the outer peripheral edge of the catheter 1. In the circumferential direction of the catheter 1, the node where the elastic member 4 intersects with the catheter 1 and the node where the elastic rod 32 intersects with the catheter 1 are staggered, so that the elastic member 4 can better pull the folding wing 5 to bend and deform around the circumference of the catheter 1.

[0057] In some embodiments, Figure 2 , Figure 4 , Figure 6 , Fig. 9 and Fig.14 As shown, the elastic member 4 can be specifically an elastic pull line with a length that can be stretched and contracted, one end of the elastic pull line is fixed to the end where the connecting portion 22 is connected to the catheter 1, the other end of the elastic pull line is fixed to the end where the connecting portion 22 is connected to the expansion portion 21, and the middle part of the elastic pull line is not connected to the connecting portion 22. The use of a retractable elastic pull line as the elastic member 4 has the advantages of simple structure and easy production. In an alternative embodiment, the elastic member 4 is not limited to a linear elastic structure form, and the elastic member 4 can also be a grid-shaped elastic structure form, and each grid rib of the grid-shaped elastic member 4 can be elastically stretched or contracted, as long as the elastic member 4 can drive the folding wings 5 ​​to bend around the circumference of the catheter 1.

[0058] In some embodiments, Figure 3 , Fig.10 , Figure 15-Figure 20 As shown, the portion of the catheter 1 located inside the balloon 2 is sleeved with two developing rings 6 for indicating the position of the balloon 2, and the two developing rings 6 are respectively aligned with the two axial ends of the expansion portion 21. The developing rings 6 are visible under X-rays and can mark the position of the balloon 2 during surgery, making it easier for the operator to smoothly deliver the balloon 2 to the diseased blood vessel area. Specifically, the developing rings 6 are made of platinum-iridium alloy.

[0059] In some embodiments, Figure 3 , Fig.10 , Figure 15-Figure 20 As shown, there are two elastic support members 3, and each elastic support member 3 is connected to one of the developing rings 6. Specifically, a plurality of grooves are provided on one side of the developing ring 6 close to the elastic support member 3, and the number of the grooves is the same as the number of the elastic rods 32 on the elastic support member 3 and the positions are arranged one by one, and the notches of the plurality of grooves are all facing the elastic rods 32, and the elastic rods 32 are all inserted into the grooves corresponding to one of the positions along the axial direction of the developing ring 6. The method of fixing the position of the elastic rod 32 by the grooves on the developing ring 6 can improve the stability of the installation structure of the elastic rod 32. Furthermore, the concave and convex matching parts of the developing ring 6 and the elastic rod 32 can also be fixed by gluing to further improve the connection reliability between the two and prevent the elastic rod 32 from loosening along the axial direction of the catheter 1 when subjected to force.

[0060] In some embodiments, the material of the balloon 2 is any one or more of polyvinyl chloride, polyethylene, polyurethane, polyamide, polyether block polyamide, and polyethylene terephthalate.

[0061] In this embodiment, when the balloon 2 is depressurized and retracted from a fully filled state to a contracted state, Figure 6-Figure 10 As shown in FIG. 1 , the fluid in the balloon 2 is drawn out, and the volume of the balloon 2 after contraction becomes smaller. Since the elastic support member 3 is provided in the balloon 2, the balloon 2 tends to retract outside the three elastic rods 32 during contraction and is combined with the three elastic rods 32 to form three folding wings 5. When the balloon 2 is further folded and rolled from the contracted state to the recovered folded state, as shown in FIG. Figure 11-Figure 15 As shown, since the volume of the balloon 2 decreases after contraction, the elastic member 4 outside the connecting portion 22 changes from the elastically stretched state to the initial state, and the length of the elastic member 4 becomes shorter. During this process, the elastic force generated by the elastic member 4 drives the elastic rods 32 in the three folding wings 5 ​​to bend and deform in the same direction around the circumference of the catheter 1. Figure 18-Figure 20 As shown, during the bending and deformation of the three elastic rods 32, the three folding wings 5 ​​bend around the circumference of the catheter 1, so that the overall outer diameter of the balloon 2 tends to be minimized, and the volume of the balloon 2 after recovery and folding is similar to that of the balloon 2 before expansion.

[0062] When the above-mentioned balloon dilatation catheter is used, the balloon 2 in the initial folded state is first delivered to the lesion site; when the balloon 2 needs to be filled, fluid is input into the inner cavity of the balloon 2 through the balloon filling interface 71 to fill the inner cavity of the balloon 2. After the inner cavity is filled, the balloon 2 expands outward along the radial direction of the catheter 1 to a fully filled state. At this time, Figure 1-Figure 5 As shown in FIG. 1 , the elastic member 4 is stretched to a certain length and accumulates elastic potential energy as the balloon 2 expands, and the elastic rod 32 is in an upright state. When the balloon 2 completes the expansion treatment of the vascular stenosis, the expanded balloon 2 needs to be depressurized. At this time, the balloon 2 is depressurized from the fully filled state and retracted to the contracted state, as shown in FIG. Figure 6-Figure 10 As shown, the fluid in the balloon 2 is drawn out, and the volume of the balloon 2 becomes smaller after contraction. Since the elastic support member 3 is provided in the balloon 2, the balloon 2 tends to retract outside the three elastic rods 32 during contraction and combines with the three elastic rods 32 to form three folding wings 5. Then the balloon 2 automatically folds and rolls from the contracted state to the recovered folded state, as shown in FIG. Figure 11-Figure 15 As shown, since the volume of the balloon 2 decreases after contraction, the elastic member 4 outside the connecting portion 22 changes from the elastically stretched state to the initial state, and the length of the elastic member 4 becomes shorter. During this process, the elastic force generated by the elastic member 4 drives the elastic rods 32 in the three folding wings 5 ​​to bend and deform in the same direction around the circumference of the catheter 1. Figure 18-Figure 20 As shown, during the bending and deformation of the three elastic rods 32, the three folding wings 5 ​​bend around the circumference of the catheter 1, so that the overall outer diameter of the balloon 2 tends to be minimized, and the volume of the balloon 2 after recovery and folding is similar to that of the balloon 2 before expansion. Then the balloon dilation catheter can be withdrawn out of the body as a whole.

[0063] To summarize, the balloon dilatation catheter provided in the embodiment of the present invention has a plurality of elastic rods 32 inside the balloon 2 that can be circumferentially bent and deformed relative to the catheter 1, and an elastic member 4 that can be stretched and deformed outside the connecting portion 22 of the balloon 2; when the balloon 2 is depressurized and retracted, the balloon 2 first retracts to the outside of the plurality of elastic rods 32 and is combined with the plurality of elastic rods 32 to form a plurality of folding wings 5, and the plurality of folding wings 5 ​​are bent and deformed in the same direction around the circumference of the catheter 1 under the action of the elastic force released by the elastic member 4, and the plurality of folding wings 5 ​​are coiled around the catheter 1, so that the overall diameter of the balloon 2 after contraction is smaller, which is conducive to withdrawing the balloon 2 from the blood vessel and avoiding damage to the blood vessel during the withdrawal process of the balloon 2.

[0064] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A balloon dilatation catheter, characterized in that: include: Catheter (1); The balloon (2) is connected to the outer periphery of the distal end of the catheter (1), and has a fully filled state in which it expands outward after the inner cavity is filled, and a recovered folded state in which it folds and rolls around the circumference of the catheter (1) after the inner cavity is depressurized; the balloon (2) comprises an expansion portion (21) and connecting portions (22) located at both axial ends of the expansion portion (21), and the connecting portions (22) are connected between the expansion portion (21) and the catheter (1); An elastic support member (3) is located inside the balloon (2), and comprises a fixing ring (31) fixed to the outer periphery of the catheter (1), and a plurality of elastic rods (32) connected to the outer periphery of the fixing ring (31) and made of elastic material; the elastic rods (32) have an upright state without elastic deformation and a bent elastic state with circumferential bending deformation around the catheter (1); An elastic member (4), both ends of which are fixed outside the connecting portion (22) and have an elastic stretching function; When the balloon (2) expands outward, the elastic member (4) is stretched along with the expansion of the balloon (2), and the elastic rod (32) recovers from the bent elastic state to the upright state; When the balloon (2) is depressurized and retracted, the balloon (2) retracts outside the plurality of elastic rods (32) in an upright state and is combined with the plurality of elastic rods (32) to form a plurality of folding wings (5). The elastic member (4) is shortened and stretched as the balloon (2) retracts. Under the action of the elastic force generated in the process of shortening and stretching the elastic member (4), the plurality of folding wings (5) are bent and deformed in the same direction around the circumference of the catheter (1).

2. The balloon dilatation catheter according to claim 1, characterized in that: The stretching direction of the elastic member (4) does not intersect with the central axis of the catheter (1).

3. The balloon dilatation catheter according to claim 1, characterized in that: The elastic member (4) is an elastic pull wire that can be stretched and contracted in length, one end of the elastic pull wire is fixed to an end where the connecting portion (22) is connected to the catheter (1), and the other end of the elastic pull wire is fixed to an end where the connecting portion (22) is connected to the expansion portion (21).

4. The balloon dilatation catheter according to claim 3, characterized in that: When the balloon (2) is in the fully filled state, the truncated cone-shaped portions at both axial ends of the balloon (2) are the connecting portions (22), and the length of the elastic pull line after being stretched is greater than the generatrix length of the truncated cone-shaped connecting portion (22).

5. The balloon dilatation catheter according to claim 4, characterized in that: The number of the elastic members (4) is three or more, and the three or more elastic members (4) are evenly arranged along the conical surface of the truncated cone-shaped connecting portion (22).

6. The balloon dilatation catheter according to claim 1, characterized in that: When the balloon (2) is in the fully filled state, the elastic rod (32) is in an upright state without elastic deformation, and an end of the elastic rod (32) away from the fixing ring (31) is spaced from the inner wall of the balloon (2).

7. The balloon dilatation catheter according to claim 1, characterized in that: The elastic rods (32) are evenly arranged in a number of three or more in the circumferential direction around the fixing ring (31).

8. The balloon dilatation catheter according to claim 1, characterized in that: The portion of the catheter (1) located inside the balloon (2) is sleeved with a developing ring (6) for indicating the position of the balloon (2), the developing ring (6) is provided with a groove, and the elastic rod (32) is inserted into the groove along the axial direction of the developing ring (6).

9. The balloon dilatation catheter according to claim 8, characterized in that: There are two of each of the developing ring (6) and the elastic support member (3), the two developing rings (6) respectively correspond to the two axial ends of the expansion portion (21), and each of the developing rings (6) is connected to one of the elastic support members (3).

10. The balloon dilatation catheter according to claim 1, characterized in that: The material of the balloon (2) is any one or more of polyvinyl chloride, polyethylene, polyurethane, polyamide, polyether block polyamide, and polyethylene terephthalate.

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