Restraint bracket for balloon catheter and balloon catheter system

Abstract

Provided are a restraint bracket for balloon catheter and a balloon catheter system. The restraint bracket comprises a restraining part and one or more connecting parts. The connecting parts are arranged at axial end parts of the restraining part, and the connecting part comprises a first axial end part and a second axial end part. The first axial end part is further away from the restraining part than the second axial end part; the second axial end part is connected to the restraining part, and the first axial end part of at least one of the connecting parts is a circumferential non-closed structure. The radial size of the first axial end of the connecting part of the restraint bracket can be increased and / or reduced as required to reduce the risk of the first axial end part scratching the outer surface of the balloon during the manufacturing process of the balloon catheter system. Moreover, the first axial end part can well match the size of a tubular part of the balloon catheter, which is beneficial to improving the propelling performance and the safety performance of the balloon catheter system.

Description

Constraint stent for balloon catheter and balloon catheter system Technical Field

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

[0002] From the 1970s to today, vascular interventional therapy has experienced rapid development. Balloon angioplasty is a fundamental procedure for the endovascular treatment of lower extremity arteriosclerosis obliterans. Common balloons include scored balloons, plain endovascular angioplasty (POBA), and drug-coated peripheral angioplasty (DCB).

[0003] The principle of balloon angioplasty is as follows: When an artery is narrowed, angiography is performed to confirm the location, diameter, and length of the stenosis, and then a balloon catheter of appropriate specifications is selected. A sheath is then inserted to establish a channel, and a guidewire is placed to establish a track. A balloon dilation catheter is then advanced externally along this channel and track until the distal end of the catheter passes through the stenosis (aligning the balloon with the stenosis). An additional pressure dilation device is used to apply pressure to the balloon catheter, causing it to expand. The balloon expands and squeezes the stenosis, converting its internal pressure into an expansion force that deforms atherosclerotic material, arterial plaque, and other particles in the stenosis, causing them to adhere to the inner wall of the vessel. Further expansion of the balloon causes appropriate tearing of the smooth muscle of the vessel wall, further expanding the vessel and its lumen. After a period of time (approximately tens of seconds to several minutes), the balloon pressure is removed and withdrawn along the guidewire and channel. Ultimately, the lumen of the stenotic segment is expanded, restoring proper blood flow.

[0004] The problem of the current balloon catheters on the market is that when they expand, the flaps of the balloon expand first, causing the flaps to contact the inner wall of the blood vessel first, resulting in uneven stress on the inner wall of the blood vessel, which is easy to tear the inner wall of the blood vessel and form a flow-restricting dissection. By installing a restraining stent on the balloon, the restraining stent can expand as the balloon expands to restrain the overall expansion of the balloon, so that the stress on the inner wall of the blood vessel is more uniform. The two ends of the restraining stent are mounted on the tubular member (e.g., inner tube or outer tube) of the balloon catheter through a connecting ring and then firmly fixed to the tubular member by heat fusion or other methods. When the radial dimension of the connecting ring is large, the risk of the connecting ring scratching the outer surface of the balloon during assembly with the balloon can be reduced. However, when the connecting ring with a large radial dimension is mounted on the tubular member for fixing, it is often difficult to fit well with the outer wall of the tubular member and a large step is formed. This large step is easy to scratch the catheter or the blood vessel wall during delivery of the balloon catheter. When the radial dimension of the connecting ring is small and matches the size of the tubular member, it is easy to scratch the outer surface of the balloon during assembly with the balloon. Summary of the Invention

[0005] The present invention provides a restraining stent for a balloon catheter and a balloon catheter system, so as to reduce the risk of the connecting end of the restraining stent scratching the outer surface of the balloon during the manufacturing process of the balloon catheter system, and the connecting end of the restraining stent can well match the size of the tubular part of the balloon catheter.

[0006] The present invention provides a restraining stent for a balloon catheter, which is used to be sheathed outside the balloon of the balloon catheter, comprising:

[0007] a restraining portion having an axial end;

[0008] One or more connecting parts, which are arranged at the axial ends of the constraint part, and the connecting parts include a first axial end and a second axial end, the first axial end is farther away from the constraint part than the second axial end, and the second axial end is connected to the constraint part, and the first axial end of at least one of the connecting parts is a circumferential non-closed structure.

[0009] In one embodiment, the circumferential non-closed structure includes at least one end connection unit in the circumferential direction, and circumferential spacing is provided on both sides of the end connection unit along the circumferential direction of the restraint bracket.

[0010] In one embodiment, the circumferential non-closed structure includes at least two end connection units that are evenly spaced apart in the circumferential direction, and the two end connection units are arranged opposite to each other in the radial direction.

[0011] In one embodiment, the shape of the end connection unit includes one or more of a circle, an ellipse, a teardrop, a triangle, a T-shape, and a fork shape.

[0012] In one embodiment, the end connection unit includes a closed or non-closed annular connection piece and a connection hole provided in the annular connection piece.

[0013] In one embodiment, the restraint bracket includes two connecting parts, namely a first connecting part and a second connecting part, the first connecting part is connected to the proximal end of the restraint part, and the second connecting part is connected to the distal end of the restraint part, and the first axial ends of the two connecting parts both include an end connection unit, and the shape of the end connection unit of the first connecting part is different from the shape of the end connection unit of the second connecting part, and the surface area of ​​the end connection unit of the first connecting part is larger than the surface area of ​​the end connection unit of the second connecting part.

[0014] In one embodiment, the first axial end further includes an intermediate connection unit arranged between the constraint portion and the end connection unit, the end connection unit is connected to the constraint portion through the corresponding intermediate connection unit, and along the circumferential direction of the constraint bracket, circumferential spacing is provided on both sides of the intermediate connection unit.

[0015] In one embodiment, the intermediate connecting unit includes a connecting rod, one end of which is connected to the constraint portion, and the other end of which is connected to the corresponding end connecting unit. The shape of the connecting rod includes one or more of a straight line, a curve, and a broken line, wherein the curve includes one or more of an arc, a wave, and a zigzag shape.

[0016] In one embodiment, the intermediate connecting unit includes a connecting rod, and the two axial ends of the connecting rod and the central axis of the constraint bracket are located in the same axial plane; or, one axial end of the connecting rod and the central axis of the constraint bracket are located in a first axial plane, and the other axial end of the connecting rod and the central axis of the constraint bracket are located in a second axial plane, and the first axial plane and the second axial plane intersect.

[0017] In one embodiment, the end of the intermediate connecting unit directly connected to the constraint portion is defined as the first end, and the end of the intermediate connecting unit directly connected to the end connecting unit is defined as the second end. The deflection direction of the second end of the intermediate connecting unit relative to the first end in the circumferential direction of the constraint bracket is opposite to the folding direction of the balloon.

[0018] The present invention also provides a constraint bracket for a balloon catheter, which is used to be mounted outside the balloon of the balloon catheter, and includes a constraint portion, the constraint portion includes a mesh structure, the mesh structure includes at least one row of meshes, each row of meshes includes at least one first mesh and at least one second mesh, the first mesh and the second mesh are alternately arranged in the circumferential direction of the constraint portion, and when the constraint portion is in a first state, the area of ​​the first mesh is larger than the area of ​​the second mesh.

[0019] By arranging the first mesh and the second mesh on the circumference of the constraint part, on the one hand, it is beneficial to improve the flexibility of the constraint part, so that the area where the constraint part is located can better adapt to the curved blood vessel morphology; on the other hand, it is beneficial to improve the retraction performance of the constraint part (that is, the ability of the constraint part to restore the initial contracted state after the balloon is contracted), so that the balloon catheter system can repeatedly expand and contract in the body while still maintaining a good treatment effect. Therefore, it can treat multiple narrow blood vessel segments in the body without repeatedly sheathing and releasing the same balloon catheter for treatment of different treatment areas, or replacing the balloon catheter multiple times to treat different treatment areas.

[0020] In one embodiment, the ratio of the area of ​​the first mesh to the area of ​​the second mesh is in the range of 1.5 to 2.5.

[0021] In one embodiment, when the constraint portion is in the second state, the area of ​​the first mesh is substantially equal to the area of ​​the second mesh.

[0022] In one embodiment, the constraint portion includes a plurality of circumferential constraint rings spaced apart in the axial direction of the constraint portion and a plurality of axial struts spaced apart in the circumferential direction of the constraint portion, and the axial struts divide the space between two adjacent circumferential constraint rings into a plurality of first meshes and a plurality of second meshes.

[0023] In one embodiment, the constraint portion includes a circumferential constraint ring, which includes a plurality of first vertices and second vertices alternately arranged in sequence along the circumference of the circumferential constraint ring, the first vertex is closer to the distal end of the constraint portion than the second vertex, and the circumferentially adjacent first and second vertices are connected by a wave rod, and the wave rod includes a first end bending section connected to the first vertex, a second end bending section connected to the second vertex, and an intermediate section with the first end bending section and the second end bending section connected at both ends respectively. When the constraint portion is in the first state, the proximal end point of the intermediate section is farther away from the busbar of the constraint portion where the first vertex is located than the distal end point of the intermediate section.

[0024] In one embodiment, the middle section includes a straight rod sub-segment and / or a middle bent sub-segment.

[0025] In one embodiment, the middle section includes a middle bending sub-segment. When the constraint portion is in the first state, the middle bending sub-segment includes an even number of bending points, and the bending directions of two adjacent bending points are opposite.

[0026] In one embodiment, the middle bending sub-segment is convexly bent at its bending point closest to the first vertex toward the direction of the busbar of the constraint portion away from the first vertex, and the bending sub-segment is convexly bent at its bending point closest to the second vertex toward the direction of the busbar of the constraint portion away from the second vertex.

[0027] In one embodiment, the constraint portion includes a circumferential constraint ring, the circumferential constraint ring includes a plurality of vertices arranged in sequence in the circumferential direction, the circumferential constraint ring also includes a wave rod connecting two adjacent vertices, the wave rod includes an end bending segment connected to the vertex, the end bending segment includes an end transition sub-segment and an end bending sub-segment, the end transition sub-segment is closer to the vertex than the end bending sub-segment; the end transition sub-segment is a straight line segment or an arc segment, and when the end transition sub-segment is an arc segment, the curvature of the end transition sub-segment is smaller than the curvature of the end bending sub-segment.

[0028] In one embodiment, the constraint portion includes a circumferential constraint ring. When in the second state, the circumference of the circumferential constraint ring and the nominal diameter of the balloon satisfy the following expression: L1∈[π(D-1),π(D-0.2)]

[0029] Wherein, L1 represents the circumference of the circumferential constraint ring, in mm, and D represents the nominal diameter of the balloon, in mm.

[0030] In one embodiment, the balloon includes two developing portions spaced apart in the axial direction. When the constraining portion is in the second state, the constraining portion completely covers the spaced area between the two developing portions in the axial direction.

[0031] The constraining stent for a balloon catheter of the present invention includes a constraining portion and a connecting portion, wherein the connecting portion is arranged at an axial end portion of the constraining portion, the connecting portion including a first axial end portion and a second axial end portion, the first axial end portion being further away from the constraining portion than the second axial end portion, the second axial end portion being connected to the constraining portion, and the first axial end portion of at least one connecting portion being a circumferentially non-closed structure. By providing a circumferentially non-closed structure at the first axial end portion of the connecting portion, the radial dimension of the first axial end portion of the connecting portion can be expanded and / or reduced as needed, thereby reducing the risk of the first axial end portion scratching the outer surface of the balloon during the manufacture of the balloon catheter system. The first axial end portion can also well match the size of the tubular member of the balloon catheter, thereby facilitating improved propulsion performance and safety performance of the balloon catheter system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a schematic structural diagram of a balloon catheter system according to an embodiment of the present invention;

[0033] FIG2 is a schematic diagram of a partial structure of a balloon catheter according to an embodiment of the present invention;

[0034] FIG3 is a schematic diagram of a partial structure of a balloon catheter system when the balloon is in an expanded state according to one embodiment of the present invention;

[0035] FIG4 is a schematic diagram of a planar expansion of a restraining bracket according to an embodiment of the present invention;

[0036] 5a to 5e are schematic structural diagrams of an end connection unit in one embodiment of the present invention;

[0037] FIG6 is a schematic diagram of a planar expansion of a restraining bracket according to an embodiment of the present invention;

[0038] FIG7 is a planar expansion schematic diagram of a restraining bracket according to another embodiment of the present invention;

[0039] FIG8 is a schematic diagram of a folded balloon according to an embodiment of the present invention;

[0040] FIG9 is a schematic diagram of a planar deployment of a restraining bracket according to an embodiment of the present invention (the black filled portion is only used to identify the first mesh and the second mesh);

[0041] FIG10 is an enlarged schematic diagram of area A in FIG9 (the black filled portion is only used to identify the first mesh and the second mesh);

[0042] FIG11 is a schematic diagram of a planar deployment of a constrained stent following balloon expansion according to an embodiment of the present invention;

[0043] FIG12 is an enlarged schematic diagram of area A in FIG9 ;

[0044] FIG13 is a schematic diagram of a partial structure of a restraining bracket according to an embodiment of the present invention;

[0045] FIG14 is a schematic diagram of a planar expansion of a restraining bracket according to an embodiment of the present invention;

[0046] FIG15 is an enlarged schematic diagram of area B in FIG14 ;

[0047] FIG16 is a planar unfolding schematic diagram of a restraining bracket according to another embodiment of the present invention;

[0048] FIG17 is a planar expansion diagram of a restraining bracket according to another embodiment of the present invention;

[0049] FIG18 is a schematic structural diagram of an additional portion according to an embodiment of the present invention;

[0050] FIG19 is a schematic structural diagram of a balloon catheter system according to one embodiment of the present invention;

[0051] FIG20 is a schematic diagram of a planar expansion of a restraining bracket according to an embodiment of the present invention;

[0052] FIG21 is a schematic diagram of a partial structure of a balloon catheter system when the balloon is in an expanded state according to one embodiment of the present invention;

[0053] FIG22 is a schematic structural diagram of a balloon in an expanded state according to an embodiment of the present invention;

[0054] FIG23 is a schematic diagram of a planar expansion of a restraining bracket according to an embodiment of the present invention;

[0055] FIG24 is a schematic diagram of a partial structure of a balloon catheter system when the balloon is in an expanded state according to one embodiment of the present invention;

[0056] FIG25 is a schematic structural diagram of a traction unit according to an embodiment of the present invention;

[0057] FIG. 26 is a schematic structural diagram of a position limiting portion in one embodiment of the present invention. DETAILED DESCRIPTION

[0058] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0059] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0061] In the field of interventional medical devices, the end of a medical device implanted in the human or animal body that is closer to the operator is generally called the "proximal end", and the end farther from the operator is called the "distal end". The "proximal end" and "distal end" of any component of a medical device are defined based on this principle.

[0062] Example 1

[0063] 1 and 2 , this embodiment provides a balloon catheter system 100, which includes a balloon catheter 10 and a constraining stent 20. The balloon catheter 10 may include a balloon 11 and a tubular assembly 12. The balloon 11 is provided with a constraining stent 20 for limiting its expansion.

[0064] The balloon 11 can expand and contract radially under the control of the operator. The balloon 11 has an inner cavity. The radial expansion and radial contraction of the balloon 11 can be controlled by injecting a medium (liquid or gas, etc.) into the inner cavity of the balloon 11 and extracting the medium. When the balloon 11 is in an expanded state, the balloon 11 includes a proximal segment 111, a distal segment 113 and a middle segment 112 with both ends respectively connected to the proximal segment 111 and the distal segment 113. Among them, the middle segment 112 of the balloon 11 is the area where the balloon 11 has a therapeutic effect (also called the effective area). In this embodiment, the cross-sectional shape of the balloon 11 is roughly circular. In other embodiments, the cross-sectional shape of the balloon 11 can also be any other suitable shape such as an ellipse, a crescent shape, a semicircle, etc. The proximal section 111 and the distal section 113 are generally conical, and the middle section 112 is generally cylindrical. The cross-sectional area of ​​the proximal end of the proximal section 111 is smaller than the cross-sectional area of ​​the distal end of the proximal section 111, the cross-sectional areas of the middle section 112 are generally equal, and the cross-sectional area of ​​the proximal end of the distal section 113 is larger than the cross-sectional area of ​​the distal end of the distal section 113. In other embodiments, the shapes of the proximal section 111, the distal section 113, and the middle section 112 of the balloon 11 can be any suitable shape. The balloon 11 can be a semi-compliant balloon or a compliant balloon, for example, made of one or a mixture of nylon, Pebax, polyurethane, latex, polyethylene terephthalate, and polyethylene.

[0065] The tubular assembly 12 includes at least one tubular member. For example, the tubular assembly 12 includes two tubular members, namely an inner tube 121 and an outer tube 122. The inner tube 121 is disposed within the outer tube 122, axially extending through the inner lumen of the balloon 11 and fixedly connected to the distal end of the balloon 11. The distal end of the outer tube 122 is fixedly connected to the proximal end of the balloon 11. A delivery channel is formed between the inner tube 121 and the outer tube 122. The delivery channel is in communication with the inner lumen of the balloon 11, through which a medium can be injected into or withdrawn from the inner lumen of the balloon 11. The inner tube 121 also includes a guidewire channel, through which a guidewire can axially extend through the inner tube 121.

[0066] The constraint bracket 20 is sleeved on the outside of the balloon 11 and is capable of limiting the expanded shape of the balloon 11. Referring to Figures 2, 3, and 4, the constraint bracket 20 includes a constraint portion 21 and a connecting portion 27. In this embodiment, the constraint portion 21 is only provided on the middle section 112 of the balloon 11, that is, the constraint portion 21 does not extend to the proximal section 111 and the distal section 113 of the balloon 11. A plurality of constraint holes (or gaps) are provided on the constraint portion 21. When the pressure inside the balloon 11 reaches a preset pressure (for example, the inside of the balloon 11 reaches a nominal pressure) and is in an expanded state, since the constraint portion 21 contacts part of the outer surface of the balloon 11 and limits the radial expansion of the balloon 11 in the contact area with the outer surface of the balloon 11, the area of ​​the balloon 11 not restricted by the constraint portion 21 protrudes outward through the plurality of constraint holes on the constraint portion 21 to form a plurality of protrusions 115. The protrusions 115 protrude relative to the constraint portion 21 in a direction away from the inner cavity of the balloon 11. The multiple protrusions 115 compress the narrowed section of the blood vessel, causing the atheromatous material, arterial plaque, etc. in the narrowed section to be squeezed and deformed, adhering to the inner wall of the blood vessel, thereby effectively dilating the blood vessels. Furthermore, because the multiple protrusions 115 form recessed areas, the squeezed atheromatous material, arterial plaque, etc. can move to the nearest recessed areas between the protrusions 115, partially relieving the squeezing force and preventing excessive tearing of the smooth muscle of the blood vessel wall, which could damage the vessel.

[0067] 1 and 4 , the connecting portion 27 is used to connect the restraining portion 21 to other components. For example, the connecting portion 27 fixes the restraining portion 21 to the tubular component 12 , so that the restraining stent 20 is fixed to the balloon catheter 10 .

[0068] Exemplarily, the connection portion 27 is disposed at an axial end of the constraint portion 21 and is connected to the constraint portion 21. In this embodiment, the connection portion 27 is provided at both ends of the constraint portion 21, wherein the connection portion 27 located at the distal end of the constraint portion 21 is fixedly connected to the inner tube 121, and the connection portion 27 located at the proximal end of the constraint portion 21 is fixedly connected to the outer tube 122, while the constraint portion 21 and the balloon 11 are not directly connected. In other embodiments, the constraint portion 21 may only have a connection portion 27 at one end. The connection portion 27 includes a first axial end and a second axial end, wherein the first axial end is further away from the constraint portion 21 than the second axial end, and the second axial end is connected to the constraint portion 21. The first axial end of at least one connection portion 27 is a circumferentially non-closed structure. The so-called circumferentially non-closed structure means that the structure has a non-closed profile in the circumferential direction and has a circumferential gap (or circumferential gap, circumferential notch). Because the first axial end is circumferentially non-closed, it can deform radially before being connected to the tubular member, thereby changing its radial dimension. By providing a circumferentially non-closed structure at the first axial end of the connecting portion 27, the radial dimension of the first axial end of the connecting portion 27 can be expanded and / or reduced as needed, thereby reducing the risk of the first axial end scraping the outer surface of the balloon 11 during the manufacture of the balloon catheter system 100. The first axial end can also well match the dimensions of the tubular member of the balloon catheter 10, thereby improving the propulsion performance and safety of the balloon catheter system 100. For example, in some embodiments, the first axial end has an end opening, and in a natural state (i.e., when not subject to external force), the radial dimension of the first axial end matches the outer diameter of the tubular member to be sleeved, thereby reducing the probability of a large step being formed after the first axial end and the tubular member are connected. Furthermore, during the sleeve process with the balloon 11, the first axial end can be radially deformed, thereby expanding the end opening, allowing the balloon 11 to enter the constraining stent 20 through the end opening, thereby reducing the risk of the first axial end scraping the surface of the balloon 11. In some embodiments, the radial dimension of the first axial end in its natural state is sufficiently large (for example, its end opening is larger than the maximum radial dimension of the constraining stent 20). During the assembly process with the balloon 11, the risk of the first axial end scraping the surface of the balloon 11 can be reduced. During the connection process with the tubular member, the radial dimension of the first axial end can be reduced, for example, by reducing its end opening to match the outer diameter of the tubular member, thereby reducing the probability of a large step being formed after the first axial end and the tubular member are connected to each other. In some embodiments, the radial dimension of the first axial end in its natural state can be any other suitable dimension. During the assembly process with the balloon catheter 10, the probability of a large step being formed after the first axial end and the tubular member are connected to each other can be reduced by expanding or reducing its radial dimension, and the risk of the first axial end scraping the surface of the balloon 11 can be reduced.

[0069] In this embodiment, the first axial ends of the connecting portion 27 connecting the two axial ends of the constraining portion 21 are both circumferentially non-closed structures. This allows both axial ends of the constraining stent 20 to be well adapted to tubular members of different diameters (in this embodiment, the outer diameter of the inner tube 121 is smaller than the inner diameter of the outer tube 122). When the balloon 11 is inserted into the inner lumen of the constraining stent 20, either end can be selected for insertion. In other embodiments, only the first axial end of the connecting portion 27 at one axial end of the constraining portion 21 can be circumferentially non-closed, which can also solve the technical problems of the present invention.

[0070] In this embodiment, the circumferentially non-closed structure includes one or more end connection units 271 and circumferential spacers 273 disposed on either side of the end connection units 271. The end connection units 271 can be connected to the tubular member. When there are multiple end connection units 271, the multiple end connection units 271 are arranged along the circumference of the tubular member, with at least two end connection units 271 forming a spaced relationship around the circumference of the constraining stent 20. Before the end connection units 271 are connected to the tubular member, the end connection units 271 can at least move in the radial direction relative to the constraining portion 21 of the constraining stent 20. Before connecting to the tubular member, pushing any end connection unit 271 can change the radial size of the end opening of the first axial end, resulting in simple operation and high efficiency. This can reduce the risk of the first axial end end scratching the outer surface of the balloon 11 during the manufacturing process of the balloon catheter system 100, and the first axial end end can well match the size of the tubular member of the balloon catheter 10. Due to the existence of the circumferential gap 273, the end connection unit 271 can move more easily relative to the constraint portion 21 and has a larger movement space, so that the circumferential non-closed structure can undergo radial deformation more conveniently and flexibly, so that the radial dimension change space is large enough to meet a wider range of needs during the assembly process.

[0071] For example, the circumferentially non-closed structure includes at least two end connection units 271 evenly spaced about the circumference of the restraining bracket 20, with the two end connection units 271 facing each other in the radial direction of the restraining bracket 20. This arrangement facilitates uniform force distribution on the end connection units 271 and improves the secure connection between the connecting portion 27 and the tubular member, while also preventing a significant increase in the radial dimension of the connection between the end connection units 271 and the tubular member. In other embodiments, the number of end connection units 271 may be one or more than two.

[0072] 4 and 5a to 5e, in this embodiment, the shape of the end connection unit 271 includes one or more of a circle (refer to FIG5b), an ellipse (refer to FIG4 271b), a teardrop shape (refer to FIG4 271a), a triangle (refer to FIG5a and FIG5c), a T-shape (refer to FIG5d), and a fork shape (refer to FIG5e). In other embodiments, the end connection unit 271 may adopt any other suitable shape. For example, the end connection unit 271 may include a closed or non-closed annular connector 2711 and a connection hole 2712 provided in the annular connector 2711. When it is necessary to connect the end connection unit 271 to the tubular member, the end connection unit 271 can first be fully fitted to the outer surface of the tubular member, and then a heat shrink tube can be provided on the outer surface of the tubular member. The heat shrink tube can be reduced in diameter by heating and the end connection unit 271 and the tubular member can be firmly wrapped and fixed together. The provision of the annular connector and the connection hole 2712 allows the end connection unit 271 to better conform to the surface of the tubular member, resulting in a smoother surface after the two are connected, further reducing the probability of forming large steps, and thus improving the propulsion performance and safety of the balloon catheter system 100. Furthermore, during the heating process, the polymer material on the heat shrink tubing and / or the tubular member can enter the connection hole 2712 and fuse together, which helps to improve the connection strength between the end connection unit 271 and the tubular member. In particular, when the annular connector 2711 is a closed annular structure, the connection strength between the end connection unit 271 and the tubular member can be further improved.

[0073] In this embodiment, the restraining bracket 20 includes two connecting portions 27, namely a first connecting portion 27a and a second connecting portion 27b. The first connecting portion 27a is connected to the proximal end of the restraining portion 21, and the second connecting portion 27b is connected to the distal end of the restraining portion 21. The first axial ends of both connecting portions 27 include an end connecting unit 271 that is movable relative to the restraining portion 21 in the radial direction of the restraining bracket 20. For example, the end connecting unit 271 of the first connecting portion 27a is denoted as the first end connecting unit 271a, and the end connecting unit 271 of the second connecting portion 27b is denoted as the second end connecting unit 271b. The shape of the first end connecting unit 271a can be different from the shape of the second end connecting unit 271b, which helps the operator better distinguish the proximal and distal ends of the restraining bracket 20. The end connecting unit 271 of the appropriate shape can also be selected according to actual needs to connect the proximal or distal end of the restraining bracket 20 to other components. For example, the first end connection unit 271a is roughly teardrop-shaped, and the second end connection unit 271b is roughly elliptical. Both can better fit the outer surface of the tubular member and have a larger contact area with the tubular member, thereby facilitating a stable connection with the tubular member and a relatively smooth surface after connection. The first end connection unit 271a is connected to the outer tube 122, and the second end connection unit 271b is connected to the inner tube 121. Because the outer diameter of the outer tube 122 is larger than the outer diameter of the inner tube 121, the connection stability between the outer tube 122 and the end connection unit 271 is required to be higher. The teardrop shape of the first end connection unit 271a can better fit the surface of the tubular member than other shapes. Therefore, the teardrop shape of the first end connection unit 271a is conducive to improving the connection stability between the first end connection unit 271a and the outer tube 122. Furthermore, the surface area of ​​the first end connection unit 271a is greater than that of the second end connection unit 271b, which helps increase the contact area between the first end connection unit 271a and the outer tube 122, thereby further improving the connection stability between the first end connection unit 271a and the outer tube 122. The teardrop-shaped tip is connected to other components and points toward the constraint portion 21, which helps improve its flexibility relative to other components and helps reduce stress concentration at the connection between the teardrop-shaped tip and other components.

[0074] Furthermore, the connecting portion 27 may also include an intermediate connecting unit 272 provided between the constraint portion 21 and the end connecting unit 271, and the end connecting unit 271 is connected to the constraint portion 21 through the corresponding intermediate connecting unit 272. Along the circumferential direction of the constraint bracket 20, a circumferential gap 273 is provided on both sides of the intermediate connecting unit 272. Such an arrangement enables the intermediate connecting unit 272 to be movable relative to the constraint portion 21 at least in the radial direction of the constraint bracket 20, thereby facilitating further increasing the space in which the end connecting unit 271 connected thereto can be movable relative to the constraint portion 21, thereby further increasing the space for variation in the radial dimensions of the circumferential non-closed structure, and being able to meet a wider range of needs during the assembly process. In this embodiment, each end connecting unit 271 is connected to the constraint portion 21 through the corresponding intermediate connecting unit 272. In other embodiments, some or all of the end connecting units 271 may also be directly connected to the constraint portion 21.

[0075] The above-mentioned intermediate connecting unit 272 may not be directly connected to the balloon 11, so that the intermediate connecting unit 272 can move relative to the balloon 11, which is not only conducive to better sheathing during the sheathing process, but also when the length of the constraint part 21 changes due to the expansion and contraction process, the intermediate connecting unit 272 can follow its movement to a certain extent, so as not to excessively pull the balloon 11 and cause damage to the balloon 11.

[0076] Exemplarily, the intermediate connection unit 272 includes a connecting rod 2721, one end of which is connected to the constraint portion 21, and the other end is connected to the corresponding end connection unit 271. The shape of the connecting rod 2721 includes one or more of a straight line, a curved line, and a broken line, wherein the curved line includes one or more of an arc, a wave, and a sawtooth. Referring to Figures 4 and 6, in this embodiment, the shape of the connecting rod 2721 is a straight line. Referring to Figure 7, in another embodiment, the shape of the connecting rod 2721 may be a wave. When the length of the constraint portion 21 changes, the curved or broken line-shaped connecting rod 2721 itself can also change in length to a certain extent, thereby providing a change space for the length change of the constraint portion 21, which is conducive to reducing the risk of breaking the intermediate connection unit 272 when the constraint portion 21 expands and contracts.

[0077] Referring to Figure 4, in this embodiment, the two axial ends of the connecting rod 2721 and the central axis of the constraint bracket 20 can be located in the same axial plane. Referring to Figures 6 and 7, in other embodiments, one axial end of the connecting rod 2721 and the central axis of the constraint bracket 20 are located in a first axial plane, and the other axial end of the connecting rod 2721 and the central axis of the constraint bracket 20 are located in a second axial plane, and the first axial plane and the second axial plane intersect. This arrangement allows the connecting rod 2721 (even if it is a straight line) to change in length to a certain extent when the length of the constraint portion 21 changes, thereby providing room for the length change of the constraint portion 21, which helps reduce the risk of the intermediate connecting unit 272 being broken when the constraint portion 21 expands or contracts. For a curved or broken-line connecting rod 2721, the axial ends of the connecting rod 2721 are located in different axial planes, which can further reduce the risk of the intermediate connecting unit 272 being broken when the constraint portion 21 expands or contracts.

[0078] 8 , when the balloon 11 is in the initial contracted state (i.e., the initial contracted state before treatment), the balloon 11 folds to form a plurality of flaps 114, and the plurality of flaps 114 fold circumferentially in a predetermined folding direction (e.g., clockwise or counterclockwise). Furthermore, with reference to FIG6 and FIG7 , in other embodiments, the end of the intermediate connecting unit 272 directly connected to the constraint portion 21 is defined as a first end 2722, and the end of the intermediate connecting unit 272 directly connected to the end connecting unit 271 is defined as a second end 2723. The deflection direction of the second end 2723 of the intermediate connecting unit 272 relative to the first end 2722 in the circumferential direction of the constraint stent 20 is opposite to the folding direction of the balloon 11. When the balloon 11 begins to expand, the balloon 11 generates a force on the constraint portion 21 opposite to its folding direction due to the expansion. When the circumferential deflection direction of the intermediate connecting unit 272 is opposite to the folding direction of the balloon 11, it can effectively buffer the circumferential deflection force exerted on the constraint portion 21, thereby reducing the degree of deflection of the constraint portion 21, and further reducing the risk of damage and breakage of both ends of the intermediate connecting unit 272 due to the deflection of the constraint portion 21.

[0079] The structure of the restraining portion 21 of this embodiment can be various, and examples are given below with reference to the accompanying drawings.

[0080] 9 and 10 , in this embodiment, the constraint portion 21 includes a mesh structure 21a. The mesh structure 21a includes one or more rows of meshes 22, each row of meshes 22 including a plurality of meshes 22 arranged along the circumference of the constraint portion 21, the plurality of meshes 22 including one or more first meshes 22a and one or more second meshes 22b, the first meshes 22a and the second meshes 22b being arranged alternately along the circumference of the constraint portion 21. For example, in this embodiment, each row of meshes 22 is formed by alternating first meshes 22a and second meshes 22b. When the constraint portion 21 is in a first state, the area of ​​the first mesh 22a is greater than the area of ​​the second mesh 22b. The first state can be the initial natural radial contraction state of the constraint portion 21, that is, the state when the balloon 11 in the constraint portion 21 is in a contracted state and the constraint portion 21 is not subjected to an artificial external force. By providing the first mesh 22a and the second mesh 22b on the circumference of the constraint portion 21, on the one hand, it is beneficial to improve the flexibility of the constraint portion 21, so that the area where the constraint portion 21 is located can better adapt to the curved blood vessel morphology. On the other hand, it is beneficial to improve the retraction performance of the constraint portion 21 (i.e., the ability of the constraint portion 21 to return to its initial contracted state after the balloon 11 is deflated), so that the balloon catheter system 100 can repeatedly expand and contract in the body while still maintaining a good treatment effect. Therefore, it is possible to treat multiple stenotic blood vessel segments in the body without repeatedly retracting and releasing the same balloon catheter 10 for different treatment areas, or replacing the balloon catheter 10 multiple times to treat different treatment areas. Exemplarily, when the constraint portion 21 is in the first state, the ratio R of the area of ​​the first mesh 22a to the area of ​​the second mesh 22b is in the range of 1.5 to 2.5. When R is greater than 2.5, the difficulty of radial expansion of the constraint part 21 increases. When R is less than 1.5, the retraction performance of the constraint bracket 20 is poor. Therefore, by setting R within the above range, the constraint part 21 is not only easy to expand radially, but also has excellent retraction performance.

[0081] Furthermore, the mesh structure 21a includes one or more rows of meshes 22, each row of meshes 22 includes multiple meshes 22 arranged along the circumference of the constraint portion 21, the multiple meshes 22 include one or more of the above-mentioned first meshes 22a and one or more of the above-mentioned second meshes 22b, and the first meshes 22a and the second meshes 22b are alternately arranged in the axial direction of the constraint portion 21. For example, in this embodiment, each row of meshes 22 is formed by the alternating arrangement of the above-mentioned first meshes 22a and the second meshes 22b.

[0082] Referring to FIG11 , in this embodiment, when the constraint portion 21 is in the second state, the area of ​​the first mesh 22a and the area of ​​the second mesh 22b are substantially equal. For example, when the constraint portion 21 is in the second state, the areas of all meshes 22 are substantially equal, forming a quadrilateral-like shape. The second state refers to the radially expanded state of the constraint portion 21 when the pressure within the balloon 11 reaches a preset pressure (for example, the interior of the balloon 11 reaches a nominal pressure). Because the constraint portion 21 has uniform meshes 22 when in the second state, the size of the protrusions 115 (refer to FIG3 ) protruding from the multiple meshes 22 is also relatively uniform, allowing the multiple protrusions 115 to better fit the narrowed section of the blood vessel, achieving a good vascular dilation effect. At the same time, the multiple uniform protrusions 115 can apply a relatively uniform squeezing force to the inner wall of the blood vessel, thereby preventing excessive tearing of the smooth muscle of the blood vessel wall and damaging the blood vessel.

[0083] 9, 10, and 12, illustratively, the constraint portion 21 includes a plurality of circumferential constraint rings 23 spaced apart in the axial direction of the constraint portion 21 and a plurality of axial struts 26 spaced apart in the circumferential direction of the constraint portion 21. The axial struts 26 divide the space between two adjacent circumferential constraint rings 23 into a plurality of first meshes 22a and second meshes 22b. When the constraint portion 21 is in the second state, the axial struts 26 may be substantially parallel to the central axis of the constraint portion 21 (i.e., the angle between the line connecting the two axial ends of the axial struts 26 and the central axis of the constraint portion 21 does not exceed 15°). In this embodiment, the circumferential constraint rings 23 are circumferentially closed annular structures (or circumferentially closed loop structures). In other embodiments, the circumferential constraint rings 23 may be circumferentially non-closed structures (or circumferentially open loop structures).

[0084] The circumferential constraining ring 23 includes a plurality of vertices 24 spaced apart along the circumference of the circumferential constraining ring 23. These vertices 24 include first vertices 24a (or peaks) and second vertices 24b (or valleys). The first vertices 24a and the second vertices 24b are alternately spaced apart along the circumference of the circumferential constraining ring 23. For example, the first vertices 24a are closer to the distal end of the constraining portion 21 than the second vertices 24b. In other embodiments, the vertices 24 closer to the proximal end of the constraining portion 21 may be the first vertices 24a.

[0085] The first vertex 24a and the second vertex 24b adjacent in the circumferential direction are connected by wave rods 25, thereby forming a plurality of waves arranged in sequence in the circumferential direction. Each vertex 24 is connected to two wave rods 25, and the two wave rods 25 are arranged on both sides of the vertex 24 in the circumferential direction of the constraint portion 21. The wave rods 25 can expand and contract relative to the vertex 24 by deformation. When the constraint portion 21 is in the first state, the wave rods 25 on both sides of the vertex 24 are close to each other. When the constraint portion 21 is in the second state, the wave rods 25 on both sides of the vertex 24 flip in a direction away from each other and extend in the circumferential direction of the constraint portion 21. The whole and the wave rods 25 connected thereto are roughly located on the same radial plane (cross section) of the constraint portion 21.

[0086] 13 , the wave bar 25 includes a bent end section 251 connected to the vertex 24. For example, when the constraint portion 21 is in the first state, the wave bar 25 includes a first bent end section 251a connected to the first vertex 24a and a second bent end section 251b connected to the second vertex 24b. The bent end section 251 connected to the vertex 24 reduces stress at the connection between the end of the wave bar 25 and the vertex 24 during deformation of the wave bar 25, thereby reducing the risk of fracture at the connection between the wave bar 25 and the vertex 24.

[0087] To further reduce stress at the connection between the wave bar 25 and the apex 24 during deformation, when the constraint portion 21 is in the first state, the end bend segment 251 may include an end transition sub-segment 2511 and an end bend sub-segment 2512. The end transition sub-segment 2511 is closer to the apex 24 than the end bend sub-segment 2512. As shown in FIG13 , in one embodiment, the end transition sub-segment 2511 may be a straight segment. As shown in FIG14 and FIG15 , the end transition sub-segment 2511 may also be an arc segment with a smaller curvature than the end bend sub-segment 2512 to achieve a better transition connection. It is understood that in other embodiments, the end transition sub-segment 2511 may be omitted. The end bend segment 2511 can still reduce the risk of stress concentration at the connection between the wave bar 25 and the apex 24 to a certain extent.

[0088] Referring to Figure 13 , in this embodiment, when the constraint portion 21 is in the first state, the wave bar 25 may further include an intermediate section 252 whose ends connect the first end bend section 251a and the second end bend section 251b, respectively. The proximal end of the intermediate section 252 is further from the generatrix 21b of the constraint portion 21, where the first vertex 24a is located, than the distal end of the intermediate section 252. In other words, the distal end of the intermediate section 252 is further from the generatrix 21b of the constraint portion 21, where the second vertex 24b is located, than the proximal end of the intermediate section 252. This configuration reduces the amount of rotation required by the wave bar 25 toward the vertex 24 to which it is connected during the transition of the constraint portion 21 from the first state to the second state. This further reduces the likelihood of stress concentration within the end bend section 251 and at the junction between the end bend section 251 and the vertex 24, thereby further reducing the risk of fracture of the end bend section 251 itself or at the junction between the end bend section 251 and the vertex 24.

[0089] 13 and 16 , in this embodiment, when the constraint portion 21 is in the first state, the middle section 252 includes a straight rod sub-segment 2521. The included angle between the straight rod sub-segments 2521 of two adjacent wave arms 25 ranges from 8° to 35°. For example, the included angle between the straight rod sub-segments 2521 of two adjacent wave arms 25 can be 8°, 10°, 15°, 20°, 25°, 30°, 25°, etc.

[0090] Referring to Figure 14 , in another embodiment, when the restraining portion 21 is in the first state, the middle section 252 includes a middle bent sub-segment 2522. The middle bent sub-segment 2522 can be curved, including arcuate, wavy, and other shapes. The middle bent sub-segment 2522 includes at least one bending point 2523 (or bending vertex). At the bending point 2523, the middle bent sub-segment 2522 can bend convexly (or ridged) toward one circumferential direction of the restraining portion 21 or convexly toward another circumferential direction of the restraining portion 21. The provision of the middle bent sub-segment 2522 further improves the re-embracing performance of the restraining portion 21.

[0091] The bending sub-segment may include an even number of bending points 2523, with the bending directions of two adjacent bending points 2523 being opposite. This arrangement is intended to ensure that the wave shape at the first vertex 24a and the wave shape at the second vertex 24b are more consistent, resulting in a more uniform force on the wave rod 25 and better re-embracing performance of the constraint portion 21.

[0092] For example, the middle bending sub-segment 2522 in FIG15 includes two bending points 2523. The bending point 2523 closer to the first vertex 24a is designated as the first bending point 2523a, and the bending point 2523 closer to the second vertex 24b is designated as the second bending point 2523b. The middle bending sub-segment 2522 convexly bends at the first bending point 2523a toward the generatrix 21b of the constraint portion 21, away from the first vertex 24a (i.e., convexly bends toward the outside of the wave where the first vertex 24a is located). The middle bending sub-segment 2522 convexly bends at the second bending point 2523b toward the generatrix 21b of the constraint portion 21, away from the second vertex 24b (i.e., convexly bends toward the outside of the wave where the second vertex 24b is located). This configuration helps reduce the risk of stress concentration in the region of the end bending segment 251. In other embodiments, the middle bending sub-segment 2522 may include more than two even number bending points 2523. As long as the middle bending sub-segment 2522 is convexly bent at the bending point 2523 closest to the first vertex 24a toward the direction of the busbar 21b of the constraint portion 21 away from the first vertex 24a, and the middle bending sub-segment 2522 is convexly bent at the bending point 2523 closest to the second vertex 24b toward the direction of the busbar 21b of the constraint portion 21 away from the second vertex 24b, the risk of stress concentration in the area where the end bending segment 251 is located can be reduced to a certain extent.

[0093] Furthermore, the middle section 252 may include straight rod sub-segments 2521 disposed at both ends of the middle bent sub-segment 2522. This arrangement allows for a smooth transition between the middle bent sub-segment 2522 and the end bent sections 251, thereby increasing the freedom of movement of the middle bent sub-segment 2522 relative to the end bent sections 251 and facilitating radial expansion of the restraining portion 21. In other embodiments, the straight rod sub-segments 2521 connecting the middle bent sub-segment 2522 may be omitted.

[0094] 9, 12, and 15, in this embodiment, each vertex 24 is fixedly connected to a corresponding axial strut 26. The axial struts 26 intersect at the vertex 24 to which they are connected, within the circumferential constraint ring 23. This allows each wave rod 25 to be connected between two circumferentially adjacent axial struts 26. The axial struts 26 and wave rods 25 together form a mesh 22. The axial struts 26 arranged axially form a circle, and the circumferential constraint ring 23 arranged axially fixedly connects each axial strut 26, circumferentially constraining the circle of axial struts 26 and forming the mesh 22. In other embodiments, not every vertex 24 is necessarily connected to an axial strut 26.

[0095] In this embodiment, the axial strut 26 extends from the proximal end of the constraint portion 21 to the distal end of the constraint portion 21. The axial strut 26 includes a plurality of axial bending segments 261 evenly arranged along the axial direction. The axial bending segments 261 can be extended and contracted by deformation to buffer the axial tension of the axial constraint ring during the deployment process. Exemplarily, the axial bending segment 261 includes two or more bending points 2523, and the bending directions at two adjacent bending points 2523 are opposite to form a wave shape. Furthermore, the axial strut 26 may also include a straight reinforcement segment 262 connecting two adjacent axial bending segments 261. The straight reinforcement segment is provided at the vertex 24 of the circumferential constraint ring 23 to enhance the connection strength of the connection between the axial strut 26 and the circumferential constraint ring 23. In other embodiments, the above-mentioned straight reinforcement segment 262 may be omitted.

[0096] In this embodiment, when in the second state, the circumference of the circumferential constraint ring 23 and the nominal diameter of the balloon 11 can satisfy the following expression: L1∈[π(D-1),π(D-0.2)]

[0097] Where L1 represents the circumference of the circumferential constraint ring 23, in mm, and D represents the nominal diameter of the balloon 11, in mm. This arrangement ensures that the raised height of the protrusion 115 (see FIG. 3 ) formed from the mesh 22 (i.e., the height relative to the constraining portion 21) is appropriate. This allows the protrusion 115 to effectively dilate blood vessels without causing vascular damage. It also prevents the constraining portion 21 from exerting excessive force on the surface of the balloon 11, potentially damaging it. In other embodiments, the circumference of the circumferential constraint ring 23 and the nominal diameter of the balloon 11 do not necessarily satisfy the above expression; appropriate parameters may be selected based on actual needs.

[0098] Further, referring to Figure 3, in this embodiment, the balloon 11 includes two developing portions 123 spaced apart in the axial direction (for example, the developing portions 123 are spaced apart on the inner tube 121). When the constraint portion 21 is in the second state, the constraint portion 21 completely covers the spaced area between the two developing portions 123 in the axial direction. This arrangement includes the constraint portion 21 being able to effectively cover the entire effective area of ​​the balloon 11, so that the balloon catheter system 100 can more comprehensively and effectively achieve expansion of the entire narrow area, avoiding the situation where the entire effective area of ​​the balloon 11 cannot be covered due to shortening of the constraint portion 21 during the transition from the first state to the second state.

[0099] Further, with reference to FIG17 , in this embodiment, at least one axial end portion of the constraint portion 21 is provided with an additional portion 28, which is provided between the connecting portion 27 and the constraint portion 21. The axial ends of the additional portion 28 are respectively connected to the connecting portion 27 and the constraint portion 21. When the balloon 11 is inflated, the additional portion 28 can follow the radial expansion of the balloon 11 before the constraint portion 21. The provision of the additional portion 28 is conducive to sharing part of the force for the connecting portion 27 during the expansion of the balloon 11. On the other hand, since it follows the radial expansion of the balloon 11 before the constraint portion 21, after expansion, a relative constraint in the circumferential direction is formed between the surface of the inflated balloon 11 and the additional portion 28, thereby reducing the risk of the constraint portion 21 driving the connecting portion 27 to deflect relative to the balloon 11 during the expansion process, thereby helping to reduce the risk of the connecting portion 27 breaking.

[0100] Exemplarily, the additional portion 28 includes one or more additional circumferential rings 281 and additional axial columns 282. The radial support force of the additional circumferential rings 281 is less than the radial support force of the circumferential constraint ring 23, which allows the additional portion 28 to expand faster and before the constraint portion 21. The additional circumferential rings 281 and the additional axial columns 282 enclose at least one row of additional meshes 283. Each row of additional meshes 283 includes at least one first additional mesh 283a and at least one second additional mesh 283b. The first additional mesh 283a and the second additional mesh 283b are alternately arranged in the circumferential direction of the additional portion 28. For example, in this embodiment, each row of additional meshes 283 is formed by alternating first additional meshes 283a and second additional meshes 283b. When the additional portion 28 is in the first state (i.e., the initial natural radial contraction state), the ratio of the area of ​​the first additional mesh 283a to the area of ​​the second additional mesh 283b is smaller than the ratio of the area of ​​the first mesh 22a to the area of ​​the second mesh 22b. For example, the ratio of the area of ​​the first additional mesh 283a to the area of ​​the second additional mesh 283b may be in the range of 1.0 to 1.4. Such a setting may also enable the additional portion 28 to expand faster than the constraint portion 21. Referring to Figure 18, further, the additional portion 28 may be a frustum-shaped structure as a whole, for example, the cross-sectional area of ​​the axial end farther away from the constraint portion 21 is smaller than the axial end closer to the constraint portion 21, so as to better match the shape of the end of the balloon 11, thereby being able to better respond to the expansion of the end of the balloon 11 and expand accordingly. For example, the additional portion 28 located at the distal end of the constraint portion 21 and / or the additional portion 28 located at the proximal end of the constraint portion 21 is roughly a frustum-shaped structure as a whole, and the cross-sectional area of ​​the axial end farther away from the constraint portion 21 is smaller than the axial end closer to the constraint portion 21.

[0101] Referring to Figure 1 , in this embodiment, a catheter adapter 13 may be provided at the proximal end of the tubular assembly 12 to connect the tubular assembly 12 to the outside world. The catheter adapter 13 may be provided with interfaces 131 that communicate with the delivery channel and guidewire channel of the tubular assembly 12, respectively. It should be noted that the above description of the structure of the catheter adapter 13 and tubular assembly 12 is merely exemplary. In other embodiments, the structures of the tubular assembly 12 and catheter adapter 13 may differ from those of this embodiment, and in other embodiments, the catheter adapter 13 may be omitted.

[0102] The restraining bracket 20 can be cut or woven from one or more elastic materials such as nickel-titanium alloy, stainless steel, and polymer materials. The various components of the restraining bracket 20 can be an integrated structure or can be made separately and then spliced ​​together.

[0103] It can be understood that the structures of the connecting portion 27, the restraining portion 21, and the additional portion 28 exemplified in this embodiment can be implemented separately and can also produce their respective beneficial effects, or they can be implemented in combination with each other to produce their respective beneficial effects.

[0104] Example 2

[0105] 19 and 20 , this embodiment provides a balloon catheter system 100, which includes a balloon catheter 10 and a constraining stent 20. The balloon catheter 10 may include a balloon 11 and a tubular assembly 12. The balloon 11 is provided with a constraining stent 20 for limiting its expansion.

[0106] 21 , the balloon 11 can be radially expanded and contracted under the control of the operator. The balloon 11 has an inner cavity. By injecting a medium (liquid or gas, etc.) into the inner cavity of the balloon 11 and extracting the medium, the radial expansion and radial contraction of the balloon 11 can be controlled respectively. When the balloon 11 is in an expanded state, the balloon 11 includes a proximal section 111, a distal section 113, and a middle section 112 whose two ends are respectively connected to the proximal section 111 and the distal section 113. Among them, the middle section 112 of the balloon 11 is the area of ​​action (also referred to as the effective area) where the balloon 11 has a therapeutic effect. In this embodiment, the cross-sectional shape of the balloon 11 is roughly circular. In other embodiments, the cross-sectional shape of the balloon 11 can also be any other suitable shape such as an ellipse, a crescent shape, a semicircle, etc. The proximal section 111 and the distal section 113 are roughly conical, and the middle section 112 is roughly cylindrical. The cross-sectional area of ​​the proximal end of the proximal section 111 is smaller than the cross-sectional area of ​​the distal end of the proximal section 111, and the cross-sectional area of ​​the proximal end of the distal section 113 is larger than the cross-sectional area of ​​the distal end of the distal section 113. In other embodiments, the shapes of the proximal section 111, the distal section 113, and the middle section 112 of the balloon 11 can be any suitable shape. The balloon 11 can be a semi-compliant balloon 11 or a compliant balloon 11, and can be made of one or a mixture of materials selected from nylon, Pebax, polyurethane, latex, polyethylene terephthalate, and polyethylene. The specific structure of the tubular component 12 can refer to the description of the first embodiment and is not repeated here.

[0107] 20 and 21 , the outer surface of the balloon 11 has a recessed portion 116. The constraint bracket 20 is provided on the outside of the balloon 11, which can limit the expanded shape of the balloon 11. The constraint bracket 20 includes a constraint portion 21, and the axial ends of the constraint portion 21 can be directly connected to the axial ends of the balloon 11, or connected to the axial ends of the balloon 11 through a connecting portion 27 (the specific structure of the connecting portion 27 can refer to the embodiment 1 and will not be described here). In other embodiments, the constraint portion 21 can be fixed to the axial end of the balloon 11 at only one end, and the constraint bracket 20 as a whole may not be connected to the balloon 11, but is only sleeved on the outside of the balloon 11. When the inside of the balloon 11 reaches a preset pressure (for example, the inside of the balloon 11 reaches a nominal pressure) and is in an expanded state, the constraint portion 21 contacts the outer surface of the balloon 11 and limits the radial expansion of the balloon 11 in the contact area with the outer surface of the balloon 11. The recessed portion 116 and the constraining portion 21 cooperate to form a plurality of raised portions 115 on the surface of the balloon 11. The raised portions 115 protrude relative to the constraining portion 21 and the recessed portion 116 in a direction away from the inner cavity of the balloon 11. The raised portions 115 protrude relative to the constraining portion 21 in a direction away from the inner cavity of the balloon 11. The plurality of raised portions 115 can squeeze the narrowed section of the blood vessel, causing the atherosclerotic material, arterial plaque, etc. in the narrowed section to be squeezed and deformed, adhering to the inner wall of the blood vessel, thereby achieving a good vasodilation effect. At the same time, due to the recessed areas formed between the plurality of raised portions 115, the squeezed atherosclerotic material, arterial plaque, etc. can move to the nearest recessed areas between the raised portions 115, releasing some of the squeezed force and preventing excessive tearing of the smooth muscle of the blood vessel wall and damage to the blood vessel. In addition, compared with the solution of simply constraining the surface of the balloon 11 by the constraint part 21 to form multiple protrusions 115, the solution of this embodiment can reduce the coverage of the constraint part 21 on the surface of the balloon 11, which is beneficial to improving the flexibility of the area where the balloon 11 is located, so that the balloon catheter 10 can better conform to the curvature of the blood vessel. Compared with the solution of simply setting a recessed part 116 on the surface of the balloon 11, the constraint part 21 of this embodiment can constrain and support the formed protrusions 115 to a certain extent, which can prevent the protrusions 115 from being greatly deformed due to the squeezing of the narrowed section of the blood vessel, and is beneficial to stabilizing the protruding shape of the protrusions 115, thereby ensuring that the protrusions 115 can achieve the desired vascular expansion effect.

[0108] Exemplarily, the balloon 11 includes at least two balloon bodies 112a arranged in sequence along the axial direction of the balloon catheter 10. For example, the middle section 112 of the balloon 11 includes two balloon bodies 112a arranged in sequence along the axial direction of the balloon catheter 10. The recessed portion 116 includes a circumferential recessed unit 116a located between two adjacent balloon bodies 112a. The circumferential recessed unit 116a extends circumferentially of the balloon 11. When the balloon 11 is inflated to its nominal diameter, the diameter of the circumferential recessed unit 116a is smaller than the nominal diameter of the balloon 11. In this embodiment, circumferential recessed units 116a are provided at both axial ends of each balloon body 112a. The constraint portion 21 includes axial struts 26 extending in the axial direction of the balloon 11. The number of axial struts 26 can be one or more. When there are multiple axial struts 26, the multiple axial struts 26 can be evenly spaced along the circumference of the balloon 11. When the balloon 11 reaches a preset pressure and is in an expanded state, the axial struts 26 restrict radial expansion of the balloon 11. The axial struts 26 and the circumferential recessed units 116a cooperate to form a plurality of raised portions 115 on the surface of the balloon 11. The axial ends of the axial struts 26 can be directly connected to the axial ends of the balloon 11, or connected to the axial ends of the balloon 11 via connectors 27 (the specific structure of the connector 27 can be referred to in Example 1 and will not be described in detail here). The cooperation between the circumferential recessed units 116a and the axial struts 26 allows the balloon 11 to uniformly form a plurality of raised portions 115 when the preset pressure is reached. These multiple raised portions 115 can conform well to the narrowed section of the blood vessel, achieving a good vascular dilation effect. Furthermore, the multiple uniform raised portions 115 can apply a relatively uniform compressive force to the inner wall of the blood vessel, preventing excessive tearing of the smooth muscle of the blood vessel wall and damaging the vessel. Furthermore, the axial struts 26 easily follow the expansion of the balloon 11 and effectively constrain the balloon 11 when the preset pressure is reached.

[0109] Furthermore, referring to FIG22 , the recessed portion 116 of this embodiment may also include an axial recessed unit 116b, which extends in the axial direction of the balloon 11 and intersects with the circumferential recessed unit 116a. When the balloon 11 is expanded to its nominal diameter, the axial recessed unit 116b is recessed toward the inner cavity of the balloon 11. The axial recessed unit 116b and the circumferential recessed unit 116a cooperate to form an array of raised portions 115 on the surface of the balloon 11, for example, forming a crisscross grid-like array of raised portions 115. Referring to FIG23 and FIG24 , the constraint portion 21 may also include a circumferential constraint ring 23 extending in the circumferential direction of the balloon 11. The number of the circumferential constraint rings 23 may be one or more. When there are multiple circumferential constraint rings 23, the multiple circumferential constraint rings 23 may be evenly spaced along the axial direction of the balloon 11. The specific structure of the constraint portion 21 can refer to the description of the first embodiment. Such a configuration makes it easier to form the raised portion 115. When the interior of the balloon 11 reaches a relatively low preset pressure, the raised portion 115 of a predetermined height can be formed, which is beneficial to reducing the restraining force of the constraint portion 21 on the surface of the balloon 11, thereby reducing the risk of damage to the surface of the balloon 11 by the constraint portion 21. The addition of a circumferential constraint ring 23 is also beneficial to better maintain the shape of the raised portion 115, which is beneficial to improving the vasodilation effect. For a balloon catheter system 100 in which a drug layer (e.g., a drug coating) is provided on the surface of the balloon 11, when the balloon catheter system 100 is in a delivery state, the constraint portion 21 can well protect the drug layer, reducing the risk of drug sheathing caused by the drug layer rubbing against the delivery sheath. In addition, the provision of the recessed portion 116 can further increase the surface area of ​​the balloon 11, which can increase the drug loading on the surface of the balloon 11, which is beneficial to improving the drug treatment effect.

[0110] It can be understood that in other embodiments, the recessed portion 116 may only include the circumferential recessed unit 116a, and the constraint portion 21 may only include the axial support 26; or, in other embodiments, the recessed portion 116 may only include the axial recessed unit 116b, and the constraint portion 21 may only include the circumferential constraint ring 23; of course, in other embodiments, recessed units and constraint portions 21 of other shapes or structures may be included.

[0111] In this embodiment, the constraint bracket 20 is fixedly connected to the balloon 11 through the axial end portion. For example, the axial ends of the constraint bracket 20 are respectively fixedly connected to the axial ends of the balloon 11, and the constraint portion 21 can move relative to the surface of the balloon 11. When the interior of the balloon 11 reaches a preset pressure and is in an expanded state, part or all of the constraint portion 21 is located in the recessed portion 116. This arrangement is conducive to better matching the recessed portion 116 to form a regular protrusion 115, and can increase the contact area between the surface of the balloon 11 and the inner wall of the blood vessel, which is conducive to improving the vascular dilation effect. For the balloon 11 with a drug layer on the surface, it is conducive to improving the drug application effect, and when the outer surface of the recessed portion 116 is provided with a drug layer, the constraint portion 21 can promote the fragmentation and release of the drug layer after entering the recessed portion 116.

[0112] Further, with reference to Figure 25, the balloon catheter system 100 of this embodiment may also include a traction portion 117, which is connected to the constraint portion 21 and the recessed portion 116 respectively, and is used to pull the constraint portion 21 during the expansion process of the balloon 11, so that the constraint portion 21 is located in the recessed portion 116 when the preset pressure inside the balloon 11 reaches the expanded state. By providing the traction portion 117, the probability of the constraint portion 21 entering the recessed portion 116 after the balloon 11 is expanded can be increased. Exemplarily, the traction portion 117 includes one or more of a flexible traction unit and an adhesion unit. Among them, the flexible traction unit includes a traction rope, traction line, traction wire, etc. connected to the recessed portion 116 at one end and connected to the constraint portion 21 at the other end. The flexible traction unit may be elastic or inelastic. During the expansion process of the balloon 11, the flexible traction unit can pull the portion where the constraint portion 21 is connected to it into the area of ​​the recessed portion 116 connected to it. The adhesion unit may include adhesion points. By adhering the constraint portion 21 and the recessed portion 116 at a certain adhesion point, for example, adhering the axial end of the constraint portion 21 to the corresponding recessed portion 116 region at a single adhesion point, the relative position of the constraint portion 21 and the recessed portion 116 at the adhesion point remains unchanged during the inflation process of the balloon 11, thereby encouraging other unadhered portions of the constraint portion 21 to enter the corresponding recessed portion 116 region. In other embodiments, different traction portion 117 structures may be employed to increase the probability that the constraint portion 21 enters the recessed portion 116 after the balloon 11 is inflated. In other embodiments, the traction portion 117 may be omitted.

[0113] In other embodiments, referring to Figure 26, the balloon catheter system 100 may include at least one limiting portion 118, which is arranged on one axial side of the constraint portion 21 (refer to Figure 25) and is used to limit the circumferential deflection of the constraint portion 21 relative to the balloon 11 during the expansion of the balloon 11, thereby increasing the probability of the constraint portion 21 entering the recessed portion 116 after the balloon 11 is expanded.

[0114] Exemplarily, referring to Figures 25 and 26, the constraint portion 21 is provided on the middle section 112, the proximal section 111 and the distal section 113 are located outside the constraint portion 21, and a limiting portion 118 can be provided on the proximal section 111 and / or the distal section 113. The limiting portion 118 includes a limiting groove 1181 provided on the balloon 11 and a limiting member 1182 provided in pair with the limiting groove 1181. The limiting member 1182 is provided at the axial end of the constraint portion 21 and is connected to the constraint portion 21. During the expansion process of the balloon 11, the limiting member 1182 is located in the limiting groove 1181 to limit the circumferential deflection of the constraint portion 21 relative to the balloon 11.

[0115] In other embodiments, referring to FIG. 17 , the balloon catheter system 100 may further include an additional portion 28 as described in Example 1. The specific structure and description of Example 1 are omitted here. The additional portion 28 facilitates sharing some of the force on the connecting portion 27 during balloon 11 expansion. Furthermore, since the additional portion 28 expands radially with the balloon 11 before the constraint portion 21, after expansion, a circumferential constraint is formed between the expanded balloon 11 surface and the additional portion 28. This reduces the risk of the constraint portion 21 causing the connecting portion 27 to deflect relative to the balloon 11 during expansion, further increasing the probability of the constraint portion 21 entering the recess 116 after balloon 11 expansion, and also reduces the risk of the connecting portion 27 fracturing. It is understood that the additional portion 28 may be omitted.

[0116] In this embodiment, referring to FIG. 22 , the compliance of the raised portion 115 can be set to be greater than the compliance of the recessed portion 116, so that the recessed portion 116 can better maintain its concave shape when a predetermined pressure is reached inside the balloon 11. For example, when the raised portion 115 and the recessed portion 116 are made of the same material, the compliance of the recessed portion 116 can be reduced by making the sidewall thickness of the recessed portion 116 greater than the sidewall thickness of the raised portion 115. Alternatively, a low elastic modulus layer can be provided within the recessed portion 116, where the elastic modulus of the material used for the low elastic modulus layer is less than that of the material used for the raised portion 115, to reduce the compliance of the recessed portion 116.

[0117] The restraining bracket 20 can be cut or woven from one or more elastic materials such as nickel-titanium alloy, stainless steel, and polymer materials. The various components of the restraining bracket 20 can be an integrated structure or can be made separately and then spliced ​​together.

[0118] In this embodiment, referring to FIG1 , a catheter seat 13 may be further provided at the proximal end of the tubular assembly 12 . The specific structure of the catheter seat 13 and the connection method of the tubular assembly 12 may refer to the first embodiment and will not be described in detail here. In other embodiments, the catheter seat 13 may be omitted.

[0119] It can be understood that the structures of the connecting portion 27, the restraining portion 21, the pulling portion 117, and the additional portion 28 exemplified in this embodiment can be implemented separately and can also produce their respective beneficial effects, or can be implemented in combination with each other to produce their respective beneficial effects.

[0120] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A restraining stent for a balloon catheter, which is used to be sleeved outside the balloon of the balloon catheter, and is characterized in that, Comprising: A constraint part having axial ends; One or more connection parts, the connection parts being arranged at the axial ends of the constraint part, the connection parts including a first axial end and a second axial end, the first axial end being farther from the constraint part than the second axial end, the second axial end being connected to the constraint part, and the first axial end of at least one of the connection parts being a circumferentially non-closed structure.

2. The restraint stent for balloon catheter according to claim 1, wherein, The circumferentially non-closed structure includes at least one end connection unit in the circumferential direction, and circumferential intervals are provided on both sides of the end connection unit along the circumferential direction of the constraint bracket.

3. The restraining stent for balloon catheter according to claim 1, wherein, The circumferentially non-closed structure includes at least two end connection units evenly spaced in the circumferential direction, and the two end connection units are arranged opposite to each other in the radial direction.

4. The restraining stent for a balloon catheter according to claim 2 or 3, characterized in that, The shape of the end connection unit includes one or more of circular, oval, teardrop-shaped, triangular, T-shaped, and fork-shaped.

5. The restraining stent for a balloon catheter according to claim 2 or 3, characterized in that, The end connection unit includes a closed or non-closed annular connecting member and a connection hole provided in the annular connecting member.

6. The restraint stent for a balloon catheter according to any one of claims 1 to 3, characterized in that, The constraint bracket includes two connection parts, namely a first connection part and a second connection part. The first connection part connects the proximal end of the constraint part, and the second connection part connects the distal end of the constraint part. The first axial ends of the two connection parts both include end connection units, and the shape of the end connection unit of the first connection part is different from the shape of the end connection unit of the second connection part, and the surface area of the end connection unit of the first connection part is larger than the surface area of the end connection unit of the second connection part.

7. The restraining stent for a balloon catheter according to claim 2 or 3, characterized in that, The first axial end further includes an intermediate connection unit provided between the constraint part and the end connection unit. The end connection unit is connected to the constraint part through the corresponding intermediate connection unit, and circumferential intervals are provided on both sides of the intermediate connection unit along the circumferential direction of the constraint bracket.

8. The restraint stent for balloon catheter according to claim 7, wherein, The intermediate connection unit includes a connecting rod. One end of the connecting rod is connected to the constraint part, and the other end of the connecting rod is connected to the corresponding end connection unit. The shape of the connecting rod includes one or more of linear, curved, and zigzag, wherein the curved shape includes one or more of arc-shaped, wavy, and serrated.

9. The restraining stent for a balloon catheter according to claim 1, characterized in that, The constraint part includes a mesh structure. The mesh structure includes at least one row of mesh holes. Each row of mesh holes includes at least one first mesh hole and at least one second mesh hole. The first mesh hole and the second mesh hole are alternately arranged in the circumferential direction of the constraint part. When the constraint part is in the first state, the area of the first mesh hole is larger than the area of the second mesh hole.

10. The restraining stent for a balloon catheter according to claim 9, characterized in that, The ratio range of the area of the first mesh hole to the area of the second mesh hole is 1.5 to 2.

5.

11. The restraining stent for a balloon catheter according to claim 9, wherein, When the constraint part is in the second state, the area of the first mesh hole and the area of the second mesh hole are basically equal.

12. The restraining stent for a balloon catheter according to claim 1, wherein, The constraint part includes a circumferential constraint ring, the circumferential constraint ring includes a plurality of first vertices and second vertices which are alternately arranged at intervals in the circumferential direction of the circumferential constraint ring, the first vertices are closer to the distal end of the constraint part than the second vertices, and adjacent first and second vertices in the circumferential direction are connected by a wave rod. The wave rod includes a first end bending section connected to the first vertex, a second end bending section connected to the second vertex, and an intermediate section with two ends respectively connected to the first end bending section and the second end bending section. When the constraint part is in the first state, the proximal end point of the intermediate section is farther from the generatrix of the constraint part where the first vertex is located than the distal end point of the intermediate section.

13. The restraint stent for balloon catheter according to claim 12, characterized in that, The intermediate section includes a straight rod section and / or a middle bending sub-section.

14. The restraining stent for a balloon catheter according to claim 12, characterized in that, The intermediate section includes a middle bending sub-section. When the constraint part is in the first state, the middle bending sub-section includes an even number of bending points, and the bending directions at adjacent two bending points are opposite.

15. The restraining stent for a balloon catheter according to claim 14, characterized in that, The middle bending sub-section bulges and bends in a direction away from the generatrix of the constraint part where the first vertex is located at the bending point closest to the first vertex, and the bending sub-section bulges and bends in a direction away from the generatrix of the constraint part where the second vertex is located at the bending point closest to the second vertex.

16. The restraint stent for balloon catheter according to claim 1, wherein, The constraint part includes a circumferential constraint ring, the circumferential constraint ring includes a plurality of vertices arranged at intervals in the circumferential direction, the circumferential constraint ring further includes a wave rod connecting adjacent two vertices, the wave rod includes an end bending section connected to the vertex, the end bending section includes an end transition sub-section and an end bending sub-section, and the end transition sub-section is closer to the vertex than the end bending sub-section; the end transition sub-section is a straight line section or an arc section, and when the end transition sub-section is an arc section, the radian of the end transition sub-section is smaller than the radian of the end bending sub-section.

17. A balloon catheter system, characterized in that, It includes a balloon catheter and the constraint stent as described in claims 1 to 16.

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