A balloon dilatation catheter

Abstract

The present invention discloses a balloon dilatation catheter, which belongs to the technical field of interventional treatment instruments, and includes: the catheter includes an inner tube and a multi-lumen tube, and a push rod cavity is arranged inside the multi-lumen tube; the balloon includes a balloon body that can expand radially relative to the catheter; a plurality of folding mechanisms are arranged around the circumference of the catheter, and the folding mechanism includes a folding rod assembly located inside the balloon body and a push rod movably arranged in the push rod cavity; the distal end of the push rod is rotatably connected to the proximal end of the folding rod assembly; a control mechanism is connected to the proximal end of the push rod and can slide axially and rotate circumferentially relative to the multi-lumen tube. By arranging a plurality of folding mechanisms in the balloon body, when the balloon body is depressurized and contracted, the folding mechanism is controlled to unfold and rotate through the control mechanism, thereby driving the balloon body to fold into a plurality of folding wings to wrap around the inner tube, so that the overall diameter of the balloon after contraction is minimized, which is conducive to withdrawing the balloon from the blood vessel and avoiding damage to the blood vessel during the balloon withdrawal process.

Description

Technical Field

[0001] The present invention relates to the technical field of interventional treatment instruments, 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 After the balloon is expanded, the pressure needs to be released to shrink it, and then it is withdrawn out of the body.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 and it is difficult to return to the original shape of multiple folded wings. After depressurization, the balloon usually presents a two-piece bonding 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 make the overall outer diameter of the balloon smaller when it is deflated and folded into its initial state when entering the blood vessel 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] The catheter comprises an inner tube and a multi-lumen tube, wherein the multi-lumen tube is sleeved on the outside of the inner tube; the inside of the multi-lumen tube is provided with a plurality of push rod cavities arranged along the axial direction of the multi-lumen tube;

[0009] The balloon comprises a distal tube segment connected to the distal end of the inner tube, a proximal tube segment connected to the distal end of the multi-lumen tube, and a balloon body connected between the distal tube segment and the proximal tube segment; the balloon body can expand relative to the radial direction of the catheter;

[0010] A folding mechanism is provided in multiple numbers around the circumference of the catheter, and the folding mechanism includes a folding rod assembly and a push rod; the folding rod assembly is located inside the balloon body and includes at least three folding rods that are rotatably connected; the push rod is movably arranged in the push rod cavity, and the distal end of the push rod is rotatably connected to the proximal end of the folding rod assembly;

[0011] A control mechanism is transmission-connected to the proximal end of the push rod and is capable of axial sliding and circumferential rotation relative to the multi-lumen tube;

[0012] Under the action of the control mechanism, the folding rod assembly has a linear arrangement state in which multiple folding rods are arranged in a linear manner along the axial direction of the inner tube, a planar expansion state in which at least two folding rods are rotated outward along the radial direction of the inner tube and multiple folding rods are in the same plane, and a twisted expansion state in which the folding rods are twisted after being in the planar expansion state so that the multiple folding rods are not in the same plane.

[0013] Furthermore, the folding mechanism also includes a fixing rod, and the fixing rod is fixedly connected to the distal end of the inner tube and the distal tube section.

[0014] Further, the folding rod assembly includes a first folding rod, a second folding rod and a third folding rod; the distal end of the first folding rod is rotatably connected to the proximal end of the fixed rod, the distal end of the second folding rod is rotatably connected to the proximal end of the first folding rod, the distal end of the third folding rod is rotatably connected to the proximal end of the second folding rod, and the proximal end of the third folding rod is rotatably connected to the distal end of the push rod.

[0015] Furthermore, the balloon body includes a balloon expansion section located in the middle and in a cylindrical shape, a balloon distal connecting section and a balloon proximal connecting section located at the axial ends of the balloon expansion section and in a truncated cone shape; when the folding rod assembly is in the planar unfolded state, the connecting position of the first folding rod and the second folding rod is set corresponding to the connecting position of the balloon distal connecting section and the balloon expansion section, and the connecting position of the second folding rod and the third folding rod is set corresponding to the connecting position of the balloon expansion section and the balloon proximal connecting section.

[0016] Furthermore, when the balloon is in the expanded state and the folding rod assembly is in the planar unfolded state, there is a gap between the multiple folding rods in the folding rod assembly and the inner wall of the balloon body.

[0017] Furthermore, the folding mechanisms are evenly arranged in number of three, four or more around the circumference of the catheter.

[0018] Furthermore, the proximal end of the multi-lumen tube is connected to a catheter seat, the proximal end of the push rod extends into the catheter seat, and a groove for accommodating the proximal end of the push rod is provided on the outer wall of the catheter seat; the control mechanism is arranged on the catheter seat.

[0019] Furthermore, the control mechanism includes a gear installed in the groove and sleeved and fixed on the outer periphery of the proximal end of the push rod, and a control member located on the opening side of the groove and meshingly connected to the gear; the control member is provided with a pair of limiting steps located at both axial ends of the gear.

[0020] Furthermore, the control member is an annular structure sleeved on the outer circumference of the catheter seat, and the inner wall of the control member is provided with a toothed structure meshing and transmission connected with the plurality of gears.

[0021] Furthermore, the catheter seat is provided with a guidewire interface and a balloon filling interface, the multi-lumen tube is provided with a guidewire cavity and a balloon filling cavity, the guidewire interface is communicated with the inner cavity of the inner tube through the guidewire cavity, and the balloon filling interface is communicated with the inner cavity of the balloon body through the balloon filling cavity.

[0022] The technical solution of the present invention has the following advantages: by arranging multiple folding rod assemblies inside the balloon body, multiple push tube cavities and multiple push rods are arranged in the multi-lumen tube of the catheter, the distal end of the push rod is rotatably connected to the proximal end of the corresponding folding rod assembly, and the proximal end of the push rod is connected to a control mechanism that can slide axially and rotate circumferentially relative to the multi-lumen tube; before the balloon body is depressurized and retracted, the control mechanism moves from the proximal end to the distal end along the axial direction of the multi-lumen tube, and the control mechanism drives the push rod to move from the proximal end to the distal end, thereby making the folding rod assembly rotate outward from a linear arrangement state to a planar expansion state in which multiple folding rods are in the same plane; then the fluid in the balloon body is extracted, and the balloon body is opened. After the pressure is released, the balloon body retracts to the outside of the folding rod assembly. After the pressure is released, the part of the balloon body that wraps the folding rod assembly and the folding rod assembly are combined to form a plurality of folding wings. Finally, the control mechanism is rotated along the circumference of the multi-lumen tube, and the control mechanism drives the push rod to rotate, thereby driving the plurality of folding rods of the folding rod assembly to twist a certain angle. The plurality of folding rods of the folding rod assembly are twisted from a planar unfolded state in the same plane to a twisted unfolded state in which the plurality of folding rods are not in the same plane. At the same time, the plurality of folding wings are wound around the outer circumference of the inner tube to minimize the overall diameter of the balloon after contraction, which is beneficial for 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

[0023] 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.

[0024] Figure 1 It is a schematic diagram of the three-dimensional structure of the balloon dilatation catheter in an embodiment of the present invention, wherein the balloon body is in an expanded state, and the folding rod assembly in the balloon body is in a linear arrangement state;

[0025] Figure 2 for Figure 1 A cross-sectional view of

[0026] Figure 3 for Figure 2 The enlarged view of point I in the middle;

[0027] Figure 4 for Figure 2 The enlarged view of II in the middle;

[0028] Figure 5 Schematic diagram of the three-dimensional structure of a balloon dilatation catheter in an embodiment of the present invention, wherein the balloon body is in an expanded state, and the folding rod assembly in the balloon body is in a planar unfolded state;

[0029] Figure 6 for Figure 5 A front view of

[0030] Figure 7 for Figure 6 Sectional view of the AA plane;

[0031] Figure 8 Schematic diagram of the three-dimensional structure of a balloon dilatation catheter in an embodiment of the present invention, wherein the balloon body is in a retracted state, and the folding rod assembly in the balloon body is in a twisted and unfolded state;

[0032] Fig. 9 for Figure 8 A front view of

[0033] Fig.10 for Fig. 9 Sectional view of the BB plane.

[0034] Explanation of the reference numerals in the accompanying drawings: 1. catheter; 11. inner tube; 12. multi-lumen tube; 2. balloon; 21. distal tube segment; 22. balloon body; 22a. balloon expansion segment; 22b. balloon distal connecting segment; 22c. balloon proximal connecting segment; 23. proximal tube segment; 31. folding rod assembly; 32. push rod; 33. fixing rod; 311. first folding rod; 312. second folding rod; 313. third folding rod; 4. catheter seat; 41. guidewire interface; 42. balloon filling interface; 43. groove; 5. control mechanism; 51. gear; 52. control member; 521. limit step. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] like Figure 1-Figure 10 A balloon dilatation catheter shown includes a catheter 1, a balloon 2, a plurality of folding mechanisms, a catheter seat 4 and a control mechanism 5. The catheter 1 includes an inner tube 11 and a multi-lumen tube 12, wherein the multi-lumen tube 12 is sleeved on the outside of the inner tube 11; the interior of the multi-lumen tube 12 is provided with a guidewire cavity, a balloon filling cavity and a plurality of push rod cavities arranged along the axial direction of the multi-lumen tube 12. The inner cavity of the inner tube 11 is connected to the guidewire cavity of the multi-lumen tube 12, and together serve as a guidewire channel. The catheter seat 4 is connected to the proximal end of the multi-lumen tube 12, and the catheter seat 4 is provided with a guidewire interface 41 and a balloon filling interface 42, wherein the guidewire interface 41 is connected to the inner cavity of the inner tube 11 through the guidewire cavity of the multi-lumen tube 12, and the balloon filling interface 42 is connected to the inner cavity of the balloon 2 through the balloon filling cavity, and the balloon filling interface 42 is used to fill or extract fluid into or from the balloon 2.

[0038] In this embodiment, if Figure 1 and Figure 5 As shown, the balloon 2 includes a distal tube segment 21, a proximal tube segment 23 and a balloon body 22; the distal tube segment 21 and the proximal tube segment 23 are both tubular, the distal tube segment 21 is welded and sealed at the outer periphery of the distal end of the inner tube 11, and the proximal tube segment 23 is welded and sealed at the outer periphery of the distal end of the multi-lumen tube 12. The balloon body 22 is integrally connected between the distal tube segment 21 and the proximal tube segment 23, and the balloon body 22 can expand relative to the radial direction of the inner tube 11 after the medium is flushed into the inner cavity. Specifically, the material of the balloon body 22 is one or more of polyvinyl chloride, polyethylene, polyurethane, polyamide, polyether block polyamide, polyethylene terephthalate or other polymer materials with good biocompatibility.

[0039] In this embodiment, if Figure 5 and Figure 6As shown, multiple folding mechanisms are arranged around the circumference of the catheter 1. The folding mechanism includes a folding rod assembly 31 and a push rod 32. The folding rod assembly 31 is located inside the balloon body 22 and includes at least three folding rods that are rotatably connected. The push rod 32 is movably arranged in the push rod cavity of the multi-lumen tube 12, and the distal end of the push rod 32 is rotatably connected to the proximal end of the folding rod assembly 31. The control mechanism 5 is transmission-connected to the proximal end of the push rod 32 and can slide axially and rotate circumferentially relative to the multi-lumen tube 12. In some embodiments, the folding mechanism also includes a fixing rod 33, and the fixing rod 33 is welded and fixed to the distal end of the inner tube 11 and the distal tube section 21. In other alternative embodiments, a fixing ring is welded and fixed to the outer periphery of the distal end of the inner tube 11, and a folding rod connected to the fixing ring of the folding rod assembly 31 is rotatably connected to the hinged portion at the proximal end of the fixing ring.

[0040] The folding rod assembly 31, under the action of the control mechanism 5, has a linear arrangement state in which multiple folding rods are arranged in a straight line along the axial direction of the inner tube 11, a planar deployment state in which at least two folding rods are rotated outward along the radial direction of the inner tube 11 and multiple folding rods are in the same plane, and a twisted deployment state in which multiple folding rods are twisted after being in the planar deployment state so that multiple folding rods are not in the same plane. Figure 1-Figure 3 is a schematic diagram of the folding rod assembly 31 being in a linear arrangement state, Figure 5-Figure 6 is a schematic diagram of the folding rod assembly 31 in a planar unfolded state, Figure 8-Figure 10 It is a schematic diagram of the folding rod assembly 31 in a twisted and unfolded state.

[0041] In some embodiments, Figure 5 and Figure 6 As shown, three folding mechanisms are evenly arranged around the circumference of the catheter 1; accordingly, the number of folding rod assemblies 31 in the balloon body 22 and the number of push rods 32 in the multi-lumen tube 12 are both three. In other alternative embodiments, the number of folding mechanisms can also be four or more.

[0042] In some embodiments, Figure 5 and Figure 6As shown, the folding rod assembly 31 includes a first folding rod 311, a second folding rod 312 and a third folding rod 313; the distal end of the first folding rod 311 is rotatably connected to the proximal end of the fixing rod 33, the distal end of the second folding rod 312 is rotatably connected to the proximal end of the first folding rod 311, the distal end of the third folding rod 313 is rotatably connected to the proximal end of the second folding rod 312, and the proximal end of the third folding rod 313 is rotatably connected to the distal end of the push rod 32. The balloon body 22 includes a balloon expansion section 22a located in the middle and in a cylindrical shape, a balloon distal connection section 22b and a balloon proximal connection section 22c located at both axial ends of the balloon expansion section 22a and in a truncated cone shape. When the balloon body 22 is in an expanded state and the folding rod assembly 31 is in a planar unfolded state, the connecting position of the first folding rod 311 and the second folding rod 312 is set corresponding to the connecting position of the balloon distal connecting section 22b and the balloon expansion section 22a, and the connecting position of the second folding rod 312 and the third folding rod 313 is set corresponding to the connecting position of the balloon expansion section 22a and the balloon proximal connecting section 22c. There is a gap between the first folding rod 311 and the inner wall of the balloon distal connecting section 22b, there is a gap between the second folding rod 312 and the inner wall of the balloon expansion section 22a, and there is a gap between the third folding rod 313 and the inner wall of the balloon proximal connecting section 22c. When the balloon body 22 is depressurized and retracted, the distal connecting section 22b of the balloon contracts to the first folding rod 311, and the first folding rod 311 provides support for the distal connecting section 22b of the balloon; the balloon expansion section 22a contracts to the second folding rod 312, and the second folding rod 312 provides support for the balloon expansion section 22a; the proximal connecting section 22c of the balloon contracts to the third folding rod 313, and the third folding rod 313 provides support for the proximal connecting section 22c of the balloon. It can be understood here that the number of folding rods on the folding rod assembly 31 is not limited to three, and the actual number of folding rods can be selected according to the adaptability of the shape of the balloon 2 after expansion. Figure 8-Figure 10 As shown, when the balloon body 22 is depressurized and retracted into the folding rod assembly 31 , the portion of the balloon body 22 that wraps the folding rod assembly 31 is combined with the folding rod assembly 31 to form three folding wings 6 , and the three folding wings 6 are evenly arranged around the circumference of the inner tube 11 .

[0043] In some embodiments, Figure 4 and Figure 7As shown, the proximal end of the push rod 32 extends into the catheter seat 4, and the outer wall of the catheter seat 4 is provided with three grooves 43 for accommodating the proximal ends of the three push rods 32 respectively; the control mechanism 5 is arranged on the catheter seat 4. Specifically, the control mechanism 5 includes a gear 51 installed in the groove 43 and sleeved and fixed on the outer periphery of the proximal end of the push rod 32, and a control member 52 located on the opening side of the groove 43 and meshingly connected with the gear 51; the inner side of the control member 52 is provided with a pair of limiting steps 521 located at both ends of the axial direction of the gear 51, and the pair of limiting steps 521 extend from the outside to the inside along the radial direction of the control member 52. In other alternative embodiments, the control mechanism 5 can also be arranged on a sleeve fixedly connected to the proximal end of the multi-lumen tube 12, and the sleeve can be connected to the distal end of the catheter seat 4 as an extension of the catheter seat 4, or it can be an independent component located at the distal end of the catheter seat 4 and not connected to the catheter seat 4.

[0044] In some embodiments, Figure 7 As shown, the control member 52 is an annular structure sleeved on the outer periphery of the catheter seat 4, and the inner wall of the control member 52 is provided with a toothed structure meshing and transmission connected with the three gears 51. In other alternative embodiments, the control member 52 can also be divided into three, and the three control members 52 are evenly arranged around the circumference of the catheter seat 4. Each control member 52 is specifically a gear ring or an arc-shaped rack meshing and transmission connected to the outer periphery of the corresponding single gear 51. The three gear rings or arc-shaped racks can drive the gear 51 and the push rod 32 to rotate at the same time under the action of external force, or drive the corresponding gear 51 and the push rod 32 to rotate separately.

[0045] When the above-mentioned balloon dilatation catheter is used, the balloon body 22 is in a contracted state and is sent to the lesion site, and then fluid is input into the balloon body 22 to expand the balloon body 22. The expanded balloon body 22 expands the stenotic site of the blood vessel, such as Figure 3 As shown, at this time, the first folding rod 311, the second folding rod 312, and the third folding rod 313 are connected in sequence and arranged in a straight line around the inner tube 11; when the balloon dilatation catheter needs to be withdrawn from the body, as shown in FIG. Figure 4 As shown, the operator pushes the control member 52 to move the control member 52 from the proximal end to the distal end along the outer wall of the catheter seat 4, and the control member 52 drives the push rod 32 to move from the proximal end to the distal end, thereby making the first folding rod 311, the second folding rod 312, and the third folding rod 313 radially expand from a linear arrangement state relative to the inner tube 11 to a planar expansion state in the same plane. Then the fluid in the balloon body 22 is extracted to release the pressure of the balloon body 22. Since there are three folding rod assemblies 31 in a planar expansion state in the balloon body 22, the pressure relief of the balloon body 22 will form three folding wings 6 on the three folding rod assemblies 31. Finally, as shown in FIG. Figure 8-Figure 10As shown, the operator rotates the control member 52, and the control member 52 rotates to drive the gear 51 to rotate, thereby driving the push rod 32 to rotate, and the push rod 32 drives the first folding rod 311, the second folding rod 312, and the third folding rod 313 to twist a certain angle, thereby driving the folding wings 6 of the balloon 2 to roll into Fig.10 The balloon dilatation catheter is then withdrawn from the body.

[0046] In summary, the balloon dilatation catheter provided by the embodiment of the present invention has multiple folding rod assemblies 31 arranged inside the balloon body 22, multiple push tube cavities and multiple push rods 32 arranged inside the multi-lumen tube 12 of the catheter 1, the distal end of the push rod 32 is rotatably connected to the proximal end of the corresponding folding rod assembly 31, and the proximal end of the push rod 32 is connected to the control mechanism 5 that can slide axially and rotate circumferentially relative to the multi-lumen tube 12; before the balloon body 22 is depressurized and retracted, the control mechanism 5 moves from the proximal end to the distal end along the axial direction of the multi-lumen tube 12, and the control mechanism 5 drives the push rod 32 to move from the proximal end to the distal end, thereby making the folding rod assembly 31 rotate outward from a linear arrangement state to a planar expansion state in which multiple folding rods are in the same plane; then the flow in the balloon body 22 is folded outward, and the folding rod assembly 31 is rotated outward from a linear arrangement state to a planar expansion state in which multiple folding rods are in the same plane; then the flow in the balloon body 22 is folded outward, and the folding rod assemblies 31 are folded outward, and ... The balloon body 22 is withdrawn, and the pressure is released and the balloon body 22 retracts to the outside of the folding rod assembly 31. The part of the balloon body 22 that wraps the folding rod assembly 31 after the pressure is released and the folding rod assembly 31 are combined to form a plurality of folding wings 6; finally, the control mechanism 5 is rotated along the circumferential direction of the multi-lumen tube 12, and the control mechanism 5 drives the push rod 32 to rotate, thereby driving the plurality of folding rods of the folding rod assembly 31 to twist a certain angle, and the plurality of folding rods of the folding rod assembly 31 are twisted from a planar unfolded state in the same plane to a twisted unfolded state in which the plurality of folding rods are not in the same plane. At the same time, the plurality of folding wings 6 are wound around the outer circumference of the inner tube 11, so that the overall diameter of the balloon 2 after contraction is minimized, 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.

[0047] 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: A catheter (1) comprises an inner tube (11) and a multi-lumen tube (12), wherein the multi-lumen tube (12) is sleeved on the outside of the inner tube (11); the interior of the multi-lumen tube (12) is provided with a plurality of push rod cavities arranged along the axial direction of the multi-lumen tube (12); The balloon (2) comprises a distal tube segment (21) connected to the distal end of the inner tube (11), a proximal tube segment (23) connected to the distal end of the multi-lumen tube (12), and a balloon body (22) connected between the distal tube segment (21) and the proximal tube segment (23); the balloon body (22) is capable of radial expansion relative to the catheter (1); A folding mechanism is provided in plurality around the circumference of the catheter (1), the folding mechanism comprising a folding rod assembly (31) and a push rod (32); the folding rod assembly (31) is located inside the balloon body (22) and comprises at least three folding rods that are rotatably connected; the push rod (32) is movably arranged in the push rod cavity, and the distal end of the push rod (32) is rotatably connected to the proximal end of the folding rod assembly (31); A control mechanism (5) is transmission-connected to the proximal end of the push rod (32) and is capable of axial sliding and circumferential rotation relative to the multi-lumen tube (12); Under the action of the control mechanism (5), the folding rod assembly (31) has a linear arrangement state in which the plurality of folding rods are arranged linearly along the axial direction of the inner tube (11), a planar expansion state in which at least two of the folding rods are rotated outwardly along the radial direction of the inner tube (11) and the plurality of folding rods are in the same plane, and a twisted expansion state in which the plurality of folding rods are twisted after being in the planar expansion state so that the plurality of folding rods are not in the same plane.

2. The balloon dilatation catheter according to claim 1, characterized in that: The folding mechanism further comprises a fixing rod (33), wherein the fixing rod (33) is fixedly connected to the distal end of the inner tube (11).

3. The balloon dilatation catheter according to claim 2, characterized in that: The folding rod assembly (31) includes a first folding rod (311), a second folding rod (312) and a third folding rod (313); the distal end of the first folding rod (311) is rotatably connected to the proximal end of the fixing rod (33), the distal end of the second folding rod (312) is rotatably connected to the proximal end of the first folding rod (311), the distal end of the third folding rod (313) is rotatably connected to the proximal end of the second folding rod (312), and the proximal end of the third folding rod (313) is rotatably connected to the distal end of the push rod (32).

4. The balloon dilatation catheter according to claim 3, characterized in that: The balloon body (22) includes a balloon expansion segment (22a) located in the middle and in a cylindrical shape, a balloon distal connection segment (22b) and a balloon proximal connection segment (22c) located at both axial ends of the balloon expansion segment (22a); when the folding rod assembly (31) is in the planar unfolded state, the connecting position of the first folding rod (311) and the second folding rod (312) is arranged correspondingly to the connecting position of the balloon distal connection segment (22b) and the balloon expansion segment (22a), and the connecting position of the second folding rod (312) and the third folding rod (313) is arranged correspondingly to the connecting position of the balloon expansion segment (22a) and the balloon proximal connection segment (22c).

5. The balloon dilatation catheter according to claim 1, characterized in that: When the balloon (2) is in the expanded state and the folding rod assembly (31) is in the planar unfolded state, a gap exists between the plurality of folding rods in the folding rod assembly (31) and the inner wall of the balloon body (22).

6. The balloon dilatation catheter according to claim 1, characterized in that: The folding mechanisms are evenly arranged in three, four or more numbers around the circumference of the catheter (1).

7. The balloon dilatation catheter according to any one of claims 1 to 6, characterized in that: The proximal end of the multi-lumen tube (12) is connected to a catheter seat (4), the proximal end of the push rod (32) extends into the catheter seat (4), and a groove (43) for accommodating the proximal end of the push rod (32) is provided on the outer wall of the catheter seat (4); the control mechanism (5) is arranged on the catheter seat (4).

8. The balloon dilatation catheter according to claim 7, characterized in that: The control mechanism (5) comprises a gear (51) installed in the groove (43) and sleeved and fixed on the outer periphery of the proximal end of the push rod (32), and a control member (52) located on the opening side of the groove (43) and meshingly connected with the gear (51); the control member (52) is provided with a pair of limit steps (521) located at both ends of the axial direction of the gear (51).

9. The balloon dilatation catheter according to claim 8, characterized in that: The control member (52) is an annular structure sleeved on the outer circumference of the catheter seat (4), and the inner wall of the control member (52) is provided with a toothed structure meshingly connected to the plurality of gears (51).

10. The balloon dilatation catheter according to claim 7, characterized in that: The catheter seat (4) is provided with a guidewire interface (41) and a balloon filling interface (42); the multi-lumen tube (12) is provided with a guidewire cavity and a balloon filling cavity; the guidewire interface (41) is connected to the inner cavity of the inner tube (11) through the guidewire cavity; the balloon filling interface (42) is connected to the inner cavity of the balloon body (22) through the balloon filling cavity.

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