A scalable microneedle drug balloon dilation catheter

Abstract

This invention relates to the field of medical catheter technology, specifically disclosing a retractable microneedle drug delivery balloon dilation catheter, including a catheter assembly and a balloon body located at the distal end of the catheter assembly, and further including multiple microneedle puncture units located outside the balloon body. Each microneedle puncture unit includes a receiving sleeve, a microneedle assembly, and an elastic actuator. The receiving sleeve has openings at both its top and bottom ends, and a sealing cap is provided at the top of the receiving sleeve. A puncture slit is opened at the middle position of the sealing cap. The microneedle assembly is slidably fitted inside the receiving sleeve. The elastic actuator is connected to the bottom opening of the receiving sleeve and to the bottom of the microneedle assembly. When the balloon body expands and is subjected to external pressure, the elastic actuator is compressed, causing it to elastically deform and driving the puncture end of the microneedle assembly to pass through the puncture slit and eject. This allows the microneedle to easily penetrate the hard calcified shell and enter its interior, thereby ensuring the effective establishment of a drug delivery channel.

Description

Technical Field

[0001] This invention relates to the field of medical catheter technology, and more specifically, to a retractable microneedle drug-eluting balloon dilation catheter. Background Technology

[0002] Vascular stenosis and atherosclerosis are the main causes of cardiovascular disease, and percutaneous coronary intervention (PCI) is one of the most effective treatments. In interventional therapy, drug-eluting balloon dilation catheters are widely used clinically because they can directly deliver drugs that inhibit cell proliferation to the lesion site in the vessel wall, effectively preventing restenosis. This is especially true for vascular lesions with severe calcification, where conventional simple balloon dilation often fails to adequately expand the plaque, and drugs struggle to penetrate deep into the lesion. Therefore, the industry has developed drug-eluting balloons with microneedles (microneedle balloons), designed to use microneedles to puncture the hard calcification layer and create a drug delivery channel, precisely and deeply injecting drugs into the vessel wall tissue to improve treatment efficacy and reduce side effects caused by drug loss.

[0003] Existing microneedle drug-eluting balloon dilatation catheters typically have a fixed array of microneedles attached or embedded to the surface of the balloon. When these catheters are in operation, the radial expansion force generated by the inflation of the balloon directly pushes the microneedles on the surface into the blood vessel wall. Some improved designs incorporate a folded and hidden structure, in which the microneedles are hidden within the folds of the balloon when it is not inflated. Once the balloon is inflated and expanded, the microneedles stand upright and pierce out due to the tension on the balloon surface.

[0004] However, existing microneedle drug delivery balloon technology still has two core defects in clinical applications: First, the puncture burst force is insufficient, making it difficult to effectively penetrate calcified lesions. That is, the current microneedle insertion power relies entirely on the slow radial expansion of the balloon during inflation. This static compression method is often insufficient for hard calcified plaques, easily causing the microneedle to fail to penetrate or even collapse or bend after being subjected to force, making it impossible to establish an effective drug delivery channel. Second, the microneedle is directly fixed to the surface of the flexible balloon. When the balloon is inflated, the balloon wall undergoes nonlinear tensile deformation, while the rigid microneedle base cannot extend accordingly. This causes the microneedle to tilt, collapse, or even fall off during the balloon inflation puncture process, thus affecting its effectiveness. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides a retractable microneedle drug balloon dilation catheter to at least solve one of the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A retractable microneedle drug-eluting balloon dilation catheter includes a catheter assembly and a balloon body located at the distal end of the catheter assembly, and further includes a plurality of microneedle puncture units located outside the balloon body;

[0008] The microneedle puncture unit includes a receiving sleeve, a microneedle assembly, and an elastic drive. The receiving sleeve has openings at both the top and bottom. A sealing cap is provided at the top of the receiving sleeve, and a puncture slit is provided at the middle position of the sealing cap. The microneedle assembly is slidably fitted inside the receiving sleeve. The elastic drive is connected to the bottom opening of the receiving sleeve and to the bottom of the microneedle assembly. When the balloon expands and deforms, the elastic drive is squeezed to cause elastic deformation, which drives the puncture end of the microneedle assembly to pass through the puncture slit and eject.

[0009] A connecting base is provided between the multiple microneedle puncture units and the balloon body, and the multiple microneedle puncture units are connected to the balloon body through the connecting base. When the balloon body is inflated, the connecting base extends and deforms as the surface area of ​​the balloon body increases.

[0010] Compared with the prior art, the technical effects and advantages of the present invention include at least the following:

[0011] 1. This invention uses an arched elastic sheet as a power source and utilizes its sudden deformation characteristics after being compressed to convert the static extrusion pressure of the balloon expansion into the instantaneous ejection kinetic energy of the microneedle assembly. This allows the microneedle to obtain an instantaneous impact force sufficient to break through the surface tension of hard calcified plaques, effectively solving the technical problem that traditional microneedles rely on the slow expansion of the balloon, resulting in insufficient puncture force, which leads to slippage and bending.

[0012] 2. This invention achieves a graded progressive puncture mode of "first fixed-length ejection puncture, then variable-length deep drilling" by setting a receiving sleeve with a "rigid-flexible-rigid" segmented structure and configuring the compressive strength of the axially extendable section to be greater than the sudden jump resistance of the arched elastic sheet. This allows the catheter to adaptively increase the effective extension length of the microneedle according to the actual resistance of the lesion tissue, which not only ensures deep penetration of severe thick-walled calcification, but also avoids excessive damage to the fixed long needle at the thin-walled blood vessel.

[0013] 3. This invention employs a spirally wound elastic substrate and protective wings with an elastic contraction tendency. The circumferential stretching deformation of the elastic substrate adapts to the nonlinear expansion of the balloon, ensuring that the microneedle remains perpendicular to the blood vessel wall during expansion without tilting or collapsing. At the same time, it achieves uniform distribution density changes, and the protective wings, when not in use, wrap around the containment sleeve to form a flexible streamlined profile, effectively shielding the sharp edges of rigid components. This significantly improves the catheter's passability in tortuous blood vessels and reduces the risk of scratching the vascular endothelium.

[0014] 4. This invention constructs a position-triggered drug solution switch by cooperating with the clamping protrusion, guide groove, and release recess. Combined with the conical solid tip of the microneedle and the lateral injection hole structure, it ensures that the drug solution is only released after the microneedle has fully penetrated the diseased tissue, completely eliminating premature drug leakage. At the same time, the lateral injection hole design ensures that the needle tip has high strength and hardening ability while effectively preventing tissue core extraction blockage, ensuring the accuracy and uniformity of drug delivery. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0016] Figure 2 This is a schematic diagram of a partial three-dimensional structure of the distal balloon body of the present invention;

[0017] Figure 3 This is a schematic diagram of a partial planar structure of the balloon body of the present invention;

[0018] Figure 4 This is a partial structural schematic diagram of the microneedle puncture unit of the present invention;

[0019] Figure 5 This is a schematic diagram of the internal structure of the receiving sleeve of the present invention, intended to show the unpunctured state of the microneedle;

[0020] Figure 6 This is a schematic diagram of the internal structure of the receiving sleeve of the present invention, intended to illustrate the initial puncture state of the microneedle;

[0021] Figure 7 This is a schematic diagram of the internal structure of the receiving sleeve of the present invention, intended to illustrate the state of secondary deep puncture of the microneedle.

[0022] In the above figures, the reference numerals are as follows: 1. Catheter assembly; 11. Multi-lumen tube; 12. Luer seat; 2. Balloon body; 21. Microneedle puncture unit; 211. Receiving sleeve; 2111. Rigid guide section; 2112. Axially telescopic section; 2113. Rigid connecting section; 2121. Sliding block; 2122. Microneedle; 213. Arched elastic sheet; 214. Telescopic hose; 2141. Elastic valve cavity; 221. Clamping protrusion; 222. Guide groove; 2221. Release recess; 3. Connecting base; 31. Elastic base plate; 32. Protective wing; 33. Receiving groove. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The illustrative embodiments and descriptions of this invention are for illustrative purposes only and are not intended to limit the invention. The embodiments described below are some, but not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] Furthermore, in the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] Example:

[0026] This embodiment provides a retractable microneedle drug balloon dilation catheter. Obviously, this catheter is a medical device used in the field of vascular interventional therapy. Specifically, it is usually delivered to the vascular lesion site (such as a severely calcified stenosis of the coronary artery) via a guidewire to puncture the calcified plaque and dilate the blood vessel wall and deliver drugs to the deep layers, so as to achieve efficient treatment of vascular stenosis and effective prevention of vascular restenosis.

[0027] Please see Figures 1 to 4 As shown, it includes a catheter assembly 1 and a balloon body 2 located at the distal end of the catheter assembly 1, and also includes a plurality of microneedle puncture units 21 located outside the balloon body 2;

[0028] The microneedle puncture unit 21 includes a receiving sleeve 211, a microneedle assembly, and an elastic drive. The receiving sleeve 211 has openings at both the top and bottom. A sealing cap is provided at the top of the receiving sleeve 211, and a puncture slit is provided at the middle position of the sealing cap. The microneedle assembly is slidably fitted inside the receiving sleeve 211. The elastic drive is connected to the bottom opening of the receiving sleeve 211 and is connected to the bottom of the microneedle assembly. When the balloon 2 expands and is subjected to external pressure, the elastic drive is squeezed to cause elastic deformation, which drives the puncture end of the microneedle assembly to pass through the puncture slit and eject.

[0029] A connecting base 3 is provided between the multiple microneedle puncture units 21 and the balloon body 2, and the multiple microneedle puncture units 21 are connected to the balloon body 2 through the connecting base 3. When the balloon body 2 is inflated, the connecting base 3 extends and deforms as the surface area of ​​the balloon body 2 increases.

[0030] Understandably, existing technologies have certain shortcomings in the structural design of microneedle drug delivery balloons. On the one hand, the microneedles are directly fixed to the surface of the balloon, lacking an intermediate buffer structure to adapt to the nonlinear expansion of the balloon, which makes the microneedles prone to tilting and collapsing. On the other hand, the insertion of the microneedles depends entirely on the slow expansion thrust of the balloon, lacking the instantaneous explosive force to deal with hard calcified plaques. Consequently, it is difficult to effectively penetrate some relatively hard calcified lesion areas during use, thus limiting its effectiveness.

[0031] To address this, this solution incorporates a connecting base 3 that deforms with the balloon body 2 and a microneedle puncture unit 21 containing a sleeve 211, a sealing cap, and an elastic drive component. This allows the adaptive extension deformation of the connecting base 3 to dissipate the shear stress during balloon body 2 expansion. Furthermore, the energy storage and ejection mechanism of the elastic drive component converts static compression pressure into instantaneous puncture kinetic energy, thereby effectively solving the combined technical problems of unstable microneedle 2122 posture and insufficient puncture burst force in the prior art.

[0032] Specifically, during actual catheter use, in the catheter delivery stage, the microneedle assembly is in its initial state, fully retracted and hidden inside the receiving sleeve 211, with the sealing cap physically isolating the needle tip from the external environment. Subsequently, when the balloon 2 begins to inflate, the connecting base 3 fixed to the surface of the balloon 2 responds first, extending and deforming as the surface area of ​​the balloon 2 increases. During this process, the connecting base 3 absorbs the shear stress generated by the stretching of the balloon 2 through its own deformation, and drives the multiple microneedle puncture units 21 attached to it to move away from each other to adjust the distribution density. More importantly, the connecting base 3 provides a stable support platform for the receiving sleeve 211, ensuring that the receiving sleeve 211 always maintains a perpendicular posture to the blood vessel wall, preventing the microneedle assembly from tilting due to the deformation of the balloon 2, thus laying the posture foundation for subsequent precise puncture.

[0033] Then, when the balloon 2 is further inflated and pressed against the surface of the blood vessel wall (especially calcified plaques), the microneedle puncture unit 21 is positioned between the balloon 2 and the blood vessel wall. As the balloon 2 continues to expand, under the combined effect of the outward expansion thrust of the balloon 2 and the inward reaction resistance of the blood vessel wall, the elastic drive at the bottom is forced to compress and deform and accumulate elastic potential energy. When the energy accumulates to a certain level, the elastic drive releases the rebound force, driving the puncture end of the microneedle assembly to instantly pass through the puncture suture and eject.

[0034] Therefore, compared with existing technologies, this solution cleverly utilizes the elastic drive to convert the compressive force during the expansion of the balloon body 2 into the elastic potential energy released instantaneously by the elastic drive, so as to enable the microneedle assembly to obtain extremely high instantaneous speed and impact force. This high-speed ejection impact mechanism enables the microneedle assembly to generate pressure far exceeding static compression instantaneously, allowing the microneedle 2122 to easily break through the hard calcified shell and enter its interior. This completely solves the clinical problem that existing microneedles are prone to slipping, bending or failing to penetrate when facing severe calcified lesions, thereby ensuring the effective establishment of drug delivery channels.

[0035] In some embodiments, the catheter assembly 1 is primarily used for delivering and positioning the balloon 2 within the blood vessel and providing independent fluid and instrument access. The balloon 2 refers to an expandable structure located at the distal end of the catheter assembly 1, which is made of a non-compliant or semi-compliant biocompatible material (such as nylon, PEBAX, or polyurethane). Specifically, in this embodiment, the balloon 2 is configured to expand anisotropically upon inflation, i.e., it mainly expands radially to form a cylindrical working surface of a predetermined diameter, while its axial length remains substantially unchanged or only slightly extended.

[0036] In some embodiments, the puncture slit refers to an opening on the sealing cap through which the puncture tip of the microneedle assembly protrudes. It can be a straight, cross-shaped, or star-shaped opening, and its size matches the puncture tip of the microneedle assembly.

[0037] Further possible implementations based on the above embodiments, such as Figure 5 and Figure 6 As shown, the elastic drive includes an arched elastic sheet 213 whose bottom is connected to the surface of the balloon body 2 via a connecting base. The arched elastic sheet 213 has an initial state in which it is concave away from the direction of the sealing cap, and a working state in which it is convex towards the direction of the sealing cap after being flipped over. When the balloon body 2 expands and deforms and squeezes the arched elastic sheet 213 to a preset threshold, the arched elastic sheet 213 undergoes a sudden deformation and flips over from the initial state to the working state.

[0038] Understandably, in this design, the arched elastic sheet 213 is preferably made of a polymer material (such as polyurethane) or a metal sheet (such as nickel-titanium shape memory alloy) with high resilience, and is manufactured through a precision molding process to create an asymmetric bistable mechanical characteristic: that is, its initial concave state is set as a low-potential-energy master stable state, while the working convex state is a high-potential-energy metastable state. This potential energy difference design means that after the external compressive load is removed, the elastic potential energy accumulated inside the sheet will drive it to automatically overcome the potential energy barrier and has a strong tendency to spontaneously jump back to the initial state.

[0039] It should be noted that those skilled in the art can optimize the specific structural parameters of the arched elastic sheet 213 according to actual clinical needs (such as for calcified lesions of different hardness) and catheter size through conventional mechanical simulation or limited experimental testing. For example, by adjusting the ratio of the arch height to the span of the arched elastic sheet 213, the critical load threshold required for its sudden deformation can be adjusted. By adjusting the thickness or radius of curvature of the sheet, the travel distance after flipping and the magnitude of the output impact force can be controlled. This embodiment is not limited to specific dimensional values ​​and is not the core of this application.

[0040] Obviously, due to the special steady-state design of the arched elastic sheet 213, its initial state of being concave away from the sealing cap serves as the main stable state, ensuring that the microneedle assembly always retracts reliably during non-working periods and avoiding false triggering; while when subjected to sufficient external pressure, it undergoes a nonlinear jump and enters the working state, at which point the protrusion points towards the sealing cap, and can directly push the microneedle assembly upward, causing its puncture end to pierce out instantly.

[0041] Therefore, this solution uses the aforementioned arched elastic sheet 213 as an elastic driving element, which cleverly utilizes the nonlinear sudden jump instability mechanism unique to thin shell structures, thus solving the core technical problem in the prior art where microneedles 2122 cannot effectively pierce the hard calcified layer due to a lack of instantaneous explosive force.

[0042] Specifically, the arched elastic sheet 213 has a defined mechanical critical threshold based on its geometry and material properties. During the puncture initiation phase, when the balloon 2 expands and is subjected to external pressure, the arched elastic sheet 213 first utilizes its structural stiffness in its concave state to resist the external load. In this phase, it does not undergo significant axial displacement but instead converts the externally input compressive force into internal elastic potential energy for high-density accumulation. Once the external load accumulates and exceeds the preset critical threshold, the arched elastic sheet 213 immediately becomes structurally unstable, instantly flipping from a concave steady state to a convex steady state. This transition process has an extremely high response speed, capable of releasing the previously accumulated potential energy in a very short time (milliseconds), thus converting it into extremely high instantaneous kinetic energy for the microneedle assembly. This high-speed, high-impact, short-stroke ejection method allows the microneedle to easily overcome the surface tension and structural strength of hard calcified plaques, achieving effective puncture and ensuring the establishment of a drug delivery channel.

[0043] Furthermore, when the treatment is completed, the arched elastic sheet 213 utilizes its own potential energy recovery tendency and achieves double reliable repositioning through the connection between its bottom and the surface of the balloon body 2: when the balloon body 2 is deflating under negative pressure, the surface area of ​​the balloon surface contracts sharply, and this contraction action will generate a centripetal pulling effect on the bottom of the arched elastic sheet 213; this active traction force, combined with the elastic recovery force of the sheet itself, drives the arched elastic sheet 213 to quickly and reliably flip and retract to the initial concave state, thereby completely eliminating the risk of the microneedle scratching the blood vessel wall during catheter withdrawal and ensuring the safety of the interventional procedure.

[0044] Based on the above embodiments, further possible implementations include... Figures 4 to 7 As shown in the diagram, the microneedle assembly includes a sliding block 2121 and a microneedle 2122 disposed on the upper part of the sliding block 2121. The microneedle 2122 is hollow inside and is connected to the infusion channel inside the catheter assembly 1 through a retractable hose 214 passing through the sliding block 2121. The bottom of the sliding block 2121 is connected to the top of the arched elastic sheet 213, and the outer peripheral wall of the sliding block 2121 slides in cooperation with the inner wall of the receiving sleeve 211.

[0045] Understandably, when the microneedle 2122 performs a sudden puncture, due to its extremely high instantaneous acceleration, it is highly susceptible to lateral force deviation and trajectory deflection if there is a lack of effective guiding constraints, resulting in its inability to vertically penetrate the calcified plaque. Therefore, this embodiment specifically constructs an axial guiding mechanism through the cooperation of the sliding block 2121 and the receiving sleeve 211. This rigid guide ensures the straightness of the puncture trajectory, solving the problem of poor motion stability during the high-dynamic puncture process of the microneedle 2122. Specifically, when the arched elastic sheet 213 undergoes a sudden deformation and drives the microneedle assembly upwards, the outer peripheral wall of the sliding block 2121 slides along the inner wall of the receiving sleeve 211, so that the receiving sleeve 211 applies radial limiting constraints to the sliding block 2121. This eliminates the lateral degrees of freedom of the microneedle assembly during movement, ensuring that the microneedle 2122 always exits in a straight line along the central axis of the receiving sleeve 211, thus guaranteeing the vertical puncture angle to the calcified plaque.

[0046] It is also understandable that, due to the significant relative displacement between the microneedle 2122 and the catheter assembly 1, conventional rigid connecting pipes cannot adapt to this instantaneous axial elongation, and are prone to breakage or detachment, leading to drug leakage. Therefore, this embodiment utilizes the flexible expansion and contraction of the telescopic hose 214 to compensate for the movement displacement, so that it undergoes tensile deformation synchronously with the sliding block 2121. Relying on its own elastic expansion and contraction characteristics, it adapts to the instantaneous axial displacement of the microneedle assembly relative to the receiving sleeve 211. Thus, while ensuring the continuous communication between the hollow channel inside the microneedle 2122 and the infusion channel of the catheter assembly 1, it effectively avoids the connection pipe from breaking or failing to seal due to excessive tensile stress, ensuring the reliability of drug delivery.

[0047] In some embodiments, the sliding block 2121 serves as a carrier for the microneedle 2122. Its main function is to fix the microneedle 2122 and to act as a force transmission medium between the microneedle assembly and the elastic drive. Therefore, it can adopt a variety of structural forms, such as a columnar structure with a circular, square, or polygonal cross-section. At the same time, its material can be selected from medical-grade polymers (such as polycarbonate, polyetheretherketone) or biocompatible metals (such as stainless steel, titanium alloy) to ensure its stability and safety in the in vivo environment.

[0048] In some embodiments, the function of the retractable tubing 214 is to maintain the continuity and sealing of the drug delivery channel when the microneedle assembly slides. Therefore, it can be a corrugated tube structure, a spiral tube structure, or a straight tube made of a highly elastic material (such as silicone, polyurethane, or thermoplastic elastomer TPE) to accommodate different degrees of stretching requirements.

[0049] Based on some implementations of the above embodiments, a retractable flexible tube 214 is proposed to connect the microneedle 2122 and the infusion channel to achieve drug delivery. However, in this process, due to the sliding movement of the microneedle assembly, drug flow may occur at inappropriate times, such as when the microneedle 2122 is not fully inserted or retracted, leading to premature drug leakage, inaccurate delivery, or backflow, affecting drug delivery efficiency and therapeutic effect. To address this, this embodiment further proposes that an elastic valve cavity 2141 is formed in the middle of the retractable flexible tube 214 located on the sliding block 2121. The elastic valve cavity 2141 achieves on / off switching through radial elastic deformation. Figure 5 and Figure 6 As shown in the image.

[0050] Through the above technical solution, an elastic valve chamber 2141 is set in the middle of the sliding block 2121 in the retractable flexible tube 214, and the radial elastic deformation of the valve chamber is used to open and close the drug flow channel, which can effectively solve the problem of inaccurate drug flow control during the sliding of the microneedle assembly. Specifically, since the elastic valve chamber 2141 is located in the middle of the sliding block 2121, its open and closed state can be closely related to the axial position of the microneedle assembly. When the microneedle assembly is in the retracted or not fully inserted state, the elastic valve chamber 2141 can be designed to be in the closed state, thereby effectively preventing premature leakage or backflow of the drug, and ensuring that the drug will not be delivered before the microneedle 2122 reaches the predetermined puncture depth. When the microneedle assembly is fully inserted and reaches the target position under the action of the elastic drive, the elastic valve chamber 2141 can be designed to open automatically, so that the drug can be accurately and timely delivered to the lesion site through the microneedle 2122, thereby avoiding waste or ineffective delivery of drugs in the non-puncture state, improving the accuracy and efficiency of drug delivery, and thus improving the overall treatment effect.

[0051] It is understandable that the elastic valve cavity 2141 is a cavity structure with elastic deformation capability formed in a specific area of ​​the telescopic hose 214. Its design purpose is to control the opening and closing of the liquid flow channel through its own radial deformation under specific conditions. The elastic characteristics of this valve cavity allow it to undergo reversible shape changes under external action, thereby achieving precise control of the liquid flow. That is, the opening and closing of the liquid flow channel is controlled by the change of its radial dimension. In other words, when the elastic valve cavity 2141 is subjected to external radial pressure, its pipe wall contracts inward, narrowing or even completely closing the flow channel, thereby blocking the liquid flow; when the external radial pressure is released, the elastic valve cavity 2141 returns to its initial state by its own elasticity, the flow channel reopens, and the liquid can pass through.

[0052] Therefore, in some embodiments, the elastic valve cavity 2141 can be formed by thinning the corresponding area of ​​the wall of the retractable hose 214 to make it more radially elastic in that area. Alternatively, a section of tubing made of a highly elastic material (such as silicone rubber) can be embedded or integrated at a specific location of the retractable hose 214 to form the elastic valve cavity 2141.

[0053] Based on the above embodiments, further, as Figure 4 and Figure 5As shown, the sliding block 2121 has mounting holes on both sides that extend laterally to the elastic valve cavity 2141. A clamping protrusion 221 is elastically installed in the mounting hole. One end of the clamping protrusion 221 abuts against the elastic valve cavity 2141. A guide groove 222 extending axially is provided on the inner wall of the receiving sleeve 211 at the position corresponding to the clamping protrusion 221. A release recess 2221 with a depth greater than the groove depth and a smooth transition is provided at the far end of the guide groove 222. When the clamping protrusion 221 abuts against the bottom of the guide groove 222, it presses the elastic valve cavity 2141 inward to close it. When the clamping protrusion 221 slides into the release recess 2221, it releases the pressure on the elastic valve cavity 2141, allowing it to elastically recover and become conductive.

[0054] This solution utilizes the aforementioned method to construct a position-triggered mechanical fluid switch by setting a clamping protrusion 221 that matches the inner wall shape of the receiving sleeve 211, as well as a guide groove 222 with a depth difference and a release pit 2221. This enables precise control of the drug delivery of the microneedle 2122, thereby effectively solving the technical problem in the prior art that it is difficult to accurately synchronize the drug delivery timing and puncture depth.

[0055] Understandably, when the microneedle assembly slides within the receiving sleeve 211, if the clamping protrusion 221 is located within the conventional groove of the guide groove 222, its outer wall will abut against the bottom of the guide groove 222. Due to the elastic mounting characteristics of the clamping protrusion 221, this abutment will cause the clamping protrusion 221 to undergo radial displacement inward, thereby applying pressure to the elastic valve cavity 2141, causing it to contract radially and close, thus preventing the flow of the drug solution and avoiding the erroneous release of the drug before the microneedle 2122 has penetrated the lesion tissue. As the microneedle assembly continues to slide... When the guide slide 222 reaches the end of its stroke, the clamping protrusion 221 will move from the regular section of the guide slide 222 into the deeper release recess 2221. The depth difference of the release recess 2221 will be used to release the radial constraint between the clamping protrusion 221 and the inner wall of the receiving sleeve 211. Thus, through the elastic mounting characteristics of the clamping protrusion 221, the clamping protrusion 221 will no longer apply pressure to the elastic valve cavity 2141, so that the elastic valve cavity 2141 can quickly recover radially by its own elastic restoring force, thereby returning to its natural conduction state and allowing the liquid medicine to pass through.

[0056] It is also understood that the axial extension length of the guide groove 222 has a strict spatial correspondence with the preset puncture stroke of the microneedle assembly. That is, the length of the guide groove 222 is designed to cover the travel distance required for the microneedle assembly to move from the initial retracted position to puncture the interior of the calcified plaque, while the release recess 2221 is precisely set at the end position of this stroke. This ensures that the clamping protrusion 221 will slide into the release recess 2221 and trigger the release of the drug solution only when the puncture end of the microneedle assembly has been completely inserted and deeply embedded inside the calcified lesion area (i.e., a closed drug delivery environment has been established). This prevents the drug solution from overflowing onto the surface of the blood vessel wall or being washed away by the blood flow due to premature opening of the flow channel, thus achieving precise timing control of the elastic valve cavity 2141. Of course, those skilled in the art can flexibly adjust the length of the guide groove 222 and the position of the release recess 2221 according to actual clinical needs (such as for calcified plaques of different thicknesses or microneedle 2122 lengths of different specifications) to adapt to different puncture depth requirements.

[0057] In some embodiments, the clamping protrusion 221 is floatingly disposed in the mounting hole by means of a spring. Specifically, a positioning step with a reduced diameter is provided on the side of the mounting hole near the elastic valve cavity 2141. Correspondingly, the main body of the clamping protrusion 221 is slidably fitted in the mounting hole, and its outer peripheral wall protrudes outward to form an integrally formed abutment flange. A micro spring is sleeved on the outer periphery of the clamping protrusion 221 located between the connecting step and the positioning step, and the two ends of the micro spring abut against the connecting step and the positioning step respectively. The elastic force direction of the micro spring is configured to always push the clamping protrusion 221 outward (i.e. away from the elastic valve cavity 2141 and pointing towards the inner wall of the receiving sleeve 211).

[0058] Based on the above embodiments, as a further possible implementation, such as Figure 2 and Figure 4 As shown, the connecting base 3 includes an elastic substrate 31 spirally wound around the outside of the balloon body 2. The elastic substrate 31 undergoes circumferential tensile deformation as the balloon body 2 expands. The receiving sleeves 211 of the microneedle puncture unit 21 are equidistantly distributed along the extension direction of the elastic substrate 31, and clearance perforations are opened on the elastic substrate 31 corresponding to the receiving sleeves 211. The arched elastic sheet 213 is connected to the surface of the balloon body 2 through the clearance perforations.

[0059] Understandably, due to the nonlinear increase in surface area of ​​the balloon 2 during inflation, if the connecting base 3 is a rigid structure and cannot extend and deform accordingly, the microneedle puncture unit 21 may tilt, collapse, or even detach during the stress process. This would prevent the stable transmission of extrusion pressure, affecting the accuracy and reliability of the microneedle 2122 ejection. Therefore, this embodiment employs the above-mentioned technical solution, where the connecting base 3 uses an elastic substrate 31 spirally wound around the outside of the balloon 2. This elastic substrate 31 can undergo circumferential tensile deformation as the balloon 2 expands, effectively solving the problem that the traditional rigid connecting base 3 cannot adapt to the nonlinear expansion deformation of the balloon 2. It also ensures that the receiving sleeve 211 of the microneedle puncture unit 21 maintains an equidistant distribution and stable posture along the extension direction of the elastic substrate 31 during the inflation of the balloon 2, preventing the microneedle 2122 unit from tilting, collapsing, or detaching.

[0060] It is also understood that, in this embodiment, by providing clearance perforations on the elastic substrate 31, the arched elastic sheet 213 can be directly connected to the surface of the balloon body 2 through these perforations, ensuring an effective force transmission path between the elastic drive and the balloon body 2. Therefore, when the balloon body 2 expands and is subjected to external pressure, the elastic drive can stably and reliably receive the pressure from the balloon body 2 and convert it into the explosive force that drives the microneedle assembly to eject, significantly improving the accuracy and reliability of the microneedle 2122 puncture, thereby ensuring that the drug can be effectively and uniformly delivered to the deep layers of the lesion tissue. Therefore, by introducing a deformable connecting base 3, this solution enables the microneedle puncture unit 21 to maintain its preset working posture and position during balloon expansion, thereby overcoming the defect of traditional microneedle 2122 balloons where the microneedle 2122 is prone to collapsing or bending when facing hard calcified lesions, making it difficult to establish an effective drug delivery channel.

[0061] In some embodiments, the elastic substrate 31 can be made of medical-grade silicone, polyurethane, or other highly elastic polymer materials, and is thermoformed or injection molded into a spiral ribbon structure. It is then wound and fixed around the outside of the balloon body 2, so that when the balloon body 2 expands, it can be stretched uniformly along the circumferential direction of the balloon body 2 and follow the size change of the balloon without exerting a significant binding force on the expansion of the balloon, ensuring that the balloon can uniformly conform to the blood vessel wall. Furthermore, as the elastic substrate 31 is stretched, the spacing between the multiple receiving sleeves 211 distributed on it will also increase synchronously, thereby realizing the automatic uniform change of the distribution density of the microneedle 2122 array, expanding the treatment coverage area, and improving the use effect of the catheter.

[0062] Based on the above embodiments, as a further possible implementation, the elastic substrate 31 has upwardly extending protective side wings 32 on both sides in its width direction. The tops of the two protective side wings 32 are close to each other and have an elastic contraction tendency. The two protective side wings 32 and the elastic substrate 31 together form a semi-closed receiving groove 33. The receiving sleeve 211 is embedded in the receiving groove 33, and the outer surface height of the protective side wings 32 is flush with the top sealing cap of the receiving sleeve 211, so as to form a protective enclosure for the microneedle puncture unit 21 when the balloon 2 is not inflated. Figure 4 As shown.

[0063] Clearly, this embodiment constructs a dynamic, flexible shielding structure that adapts to the balloon's state by incorporating protective wings 32 with an elastic contraction tendency. In the uninflated delivery state, the two protective wings 32 utilize their own elastic contraction force to close inwards, tightly wrapping the receiving sleeve 211 embedded in the receiving groove 33. Since the wing height is flush with the sealing cap, it fills the geometric difference around the receiving sleeve 211, thus forming a smooth, continuous streamlined outer contour at the distal end of the catheter. This effectively shields the sharp edges of the rigid receiving sleeve 211 and the sealing cap, significantly reducing the risk of the catheter navigating tortuous or convoluted passages. The frictional resistance in severely stenotic and calcified lesions significantly improves the device's passage performance. More importantly, it constructs a flexible buffer barrier between the rigid metal components and the fragile blood vessel wall, minimizing the risk of intimal damage caused by mechanical abrasion during delivery. At the same time, this encapsulation protection mechanism effectively prevents the microneedle puncture unit 21 from being subjected to external physical damage when the catheter is not in operation, avoiding accidental triggering or structural damage to the microneedle 2122. This significantly improves the safety of catheter operation and the structural integrity of the microneedle 2122, ensuring that the microneedle 2122 can reliably perform the puncture function when needed.

[0064] A further preferred embodiment based on the above embodiments is that, in Figure 5 As shown, the receiving sleeve 211 includes, from top to bottom, a rigid guide section 2111, an axially expandable section 2112, and a rigid connecting section 2113 along its axial direction. The sealing cap is disposed at the top of the rigid guide section 2111, and the elastic drive member is connected to the bottom of the rigid connecting section 2113. The axially expandable section 2112 is located between the rigid guide section 2111 and the rigid connecting section 2113. The guide groove 222 is formed on the inner wall of the rigid connecting section 2113, and the pressure of the axially expandable section 2112 during axial compression deformation is greater than the pressure of the arched elastic sheet 213 during sudden deformation, so that the arched elastic sheet 213 preferentially undergoes sudden deformation.

[0065] Understandably, calcified plaques exhibit high heterogeneity in clinical interventional vascular treatment, with significant differences in thickness and hardness among different patients and even between different segments of the same lesion. Current techniques typically employ microneedles of fixed length 2122, but this single size makes it difficult to balance treatment safety and effectiveness: if too short, they cannot penetrate thick-walled calcifications; if too long, they are prone to damaging the adventitia at thin-walled areas.

[0066] To this end, this solution sets up a receiving sleeve 211 with a "rigid-flexible-rigid" segmented structure, and utilizes the aforementioned pre-set differences in component structural strength (i.e., stiffness cascade) to give the microneedle puncture unit 21 a unique graded progressive puncture mode, cleverly achieving adaptive coordination between puncture burst force and puncture depth.

[0067] Specifically, during the actual use of the catheter, this structure triggers the following two stages of action sequentially based on the stress deformation sequence of each component:

[0068] First, in the initial puncture phase, such as Figure 6 As shown: As the balloon body 2 expands, it compresses the microneedle puncture unit 21; however, due to the high support strength of the axially expandable section 2112, it maintains the overall height of the receiving sleeve 211 under the initial compressive force. At this time, the arched elastic sheet 213 preferentially responds to the pressure of the balloon body 2 and undergoes a sudden deformation, driving the microneedle 2122 to slide upward relative to the rigid connecting section 2113 and pass through the sealing cap, quickly piercing out at the preset initial puncture depth. In this stage, the microneedle 2122 mainly completes the initial puncture of the surface layer of the hard calcified plaque by utilizing the instantaneous action generated by the sudden deformation.

[0069] Subsequently, during the second deep puncture phase, such as Figure 7 As shown: As the balloon body 2 continues to inflate and expand, the external pressure continues to increase. At this point, the arched elastic sheet 213 has flipped into a convex state and remains stable, no longer producing new displacement. The external pressure then overcomes the support strength of the axially expandable section 2112, forcing the axially expandable section 2112 to begin axial compression deformation, resulting in a gradual decrease in the overall height of the receiving sleeve 211. Since the bottom of the microneedle 2122 is supported on the balloon surface by the arched elastic sheet 213, its height position remains relatively unchanged, while the sealing cap at the top of the receiving sleeve 211 retracts downward as the sleeve height decreases. This directly causes the tip of the microneedle 2122 to protrude further outward relative to the sealing cap, thereby dynamically increasing the effective extension length of the microneedle 2122. During this stage, the microneedle 2122 utilizes the continuously increasing external pressure to achieve further deep insertion based on the actual thickness and resistance of the lesion tissue.

[0070] Therefore, this solution utilizes the axial compression characteristics of the receiving sleeve 211 to achieve dynamic adjustment of the effective puncture length of the microneedle 2122 during catheter use, which significantly improves the clinical applicability of the catheter: when facing thin calcifications, the catheter maintains the first-level mode to prevent excessive damage; while when facing stubborn thick-walled calcifications, the second-level mode is triggered by increasing pressure, allowing the microneedle 2122 to puncture more to achieve deep penetration, thereby greatly improving the catheter's performance.

[0071] In some embodiments, the axially extendable section 2112 preferably adopts a bellows structure. Specifically, the bellows structure has unique geometric anisotropic mechanical characteristics: on the one hand, its alternating folded structure of crests and troughs endows it with excellent axial compression capability, which can generate a large axial displacement under pressure, thereby providing sufficient travel space for adjusting the extension length of the microneedle 2122; on the other hand, the bellows structure has high circumferential stiffness in the circumferential direction, which ensures that the receiving sleeve 211 will not undergo radial collapse or twisting during the axial compression and shortening process, thereby ensuring that the movement trajectory of the microneedle assembly remains straight throughout the two-stage puncture process, avoiding the risk of needle jamming or deflection caused by sleeve deformation.

[0072] Based on the above embodiments, please further refer to... Figure 1 The catheter assembly 1 includes a multi-lumen tube 11, with a Luer seat 12 at one end away from the balloon body 2. Inside the multi-lumen tube 11, along its axial direction, there are an inflation cavity for inflating the balloon body 2, a guidewire cavity for the guidewire to pass through, and an infusion channel for delivering medication.

[0073] In this embodiment, the Luer seat 12 serves as the proximal interface of the catheter assembly 1. It has internal diversion channels that correspond one-to-one with each chamber of the multi-lumen tube 11. During use, the physician connects an external filling device and a drug injection syringe through the standard interface of the Luer seat 12, thereby accurately diverting the externally input pressure medium and drug solution and introducing them into the filling chamber and infusion channel of the multi-lumen tube 11. The multi-lumen tube 11 is responsible for independently transmitting the above-mentioned medium to the distal end, and at the same time, it uses its guidewire lumen to provide a continuous central channel for guidewire insertion. In this way, the filling, guiding and infusion functions are integrated into the same tube cross-section, which not only ensures the compactness of the overall outer diameter of the catheter, but also realizes the physical isolation and independent operation of each functional system.

[0074] In some embodiments, the multi-lumen tube 11 serves as the main mechanical transmission component connecting the proximal control handle and the distal functional component. Specifically, it can be made of polymer materials (such as polyether block amide PEBAX, nylon, or polyurethane) through a precision multi-layer co-extrusion process. Furthermore, in order to ensure the pushability and flexural strength of the catheter in tortuous blood vessels, a metal braided reinforcement layer or a spiral wound reinforcement layer is preferably integrated into the tube wall of the multi-lumen tube 11 to provide sufficient axial support and torsional control transmission capability while maintaining the flexibility of the tube body.

[0075] It is understandable that in some of the embodiments described above in this application, a microneedle puncture unit 21 is proposed to drive the microneedle 2122 to puncture the blood vessel wall and deliver drugs through an ejection mechanism when the balloon is inflated. However, in the process of its implementation, if the puncture tip of the microneedle 2122 is not properly designed, it may lead to increased puncture resistance or puncture difficulty, affecting puncture efficiency. At the same time, if the drug flows out directly through the puncture tip, it is easy to reduce the delivery effect due to tissue blockage or uneven distribution, and it is impossible to achieve precise and uniform drug release.

[0076] In a further embodiment of this application, the top of the sealing cap is arc-shaped, the puncture tip of the microneedle 2122 is a conical tip structure, and a plurality of lateral injection holes are provided on the side wall of the microneedle 2122 near the puncture tip. The lateral injection holes are located below the conical tip structure and are connected to the internal hollow flow channel of the microneedle 2122.

[0077] Understandably, the arc-shaped tip design of the sealing cap, achieved through the aforementioned technical solution, effectively reduces the frictional resistance during the ejection of the microneedle 2122, ensuring smooth puncture and preventing damage to the vessel wall. Furthermore, the conical tip structure of the microneedle 2122 significantly enhances puncture sharpness, allowing it to easily penetrate hard vessel wall tissue and reducing the risk of puncture failure. Simultaneously, multiple lateral injection holes located below the conical tip structure are opened on the sidewall of the microneedle 2122 and connected to the internal hollow flow channel, effectively solving the problem of drug blockage and uneven distribution caused by direct flow from the tip. This ensures that after the microneedle 2122 pierces the tissue, the drug can diffuse evenly and efficiently into the surrounding tissue from multiple lateral holes, preventing the holes from being blocked by tissue. This achieves precise and uniform drug release, significantly optimizing the reliability of the puncture process and the uniformity of drug delivery.

[0078] In some embodiments, the multiple lateral injection holes can be evenly distributed along the circumference of the microneedle 2122, such as opening 2, 3 or 4 holes at equal intervals on the circumference, to ensure that the drug can diffuse in multiple directions after entering the tissue; or, preferably, the lateral injection holes can also be staggered along the axial direction of the microneedle 2122 to form a spiral or staggered arrangement, thereby achieving continuous drug release over a longer tissue depth range and improving the drug penetration depth and coverage.

[0079] In some embodiments, the hollow flow channel inside the microneedle 2122 can be a single channel that runs through the axial direction of the microneedle 2122, with the lateral injection holes directly connected to the main channel. Alternatively, the hollow flow channel inside the microneedle 2122 can also be designed with a branched structure. For example, in the region near the lateral injection holes, the main channel branches into multiple smaller channels, each connected to a different lateral injection hole, to optimize the hydrodynamic characteristics of the drug and ensure uniform drug flow in each hole.

[0080] As an alternative implementation, in order to ensure the therapeutic effect, in addition to applying the drug directly to the lesion site through the microneedle 2122, a drug coating can also be applied to the outer surface of the puncture end of the microneedle 2122 by spraying, dipping or deposition processes.

[0081] Preferably, the drug coating comprises a derivative selected from paclitaxel, rapamycin (sirolimus), zotamoxetine, everolimus, or any combination thereof. By using the action of the microneedle 2122 puncturing into the blood vessel wall, the drug coating can be directly carried and delivered to the tunica media of the blood vessel. After the microneedle is inserted, the drug coating directly contacts and is released from the target site of the smooth muscle cells in the tunica media, realizing precise deep drug delivery within the lesion. This effectively solves the problem of drug loss due to blood flow during catheter delivery in traditional technologies, ensuring the accuracy of drug dosage when reaching the lesion site.

[0082] In summary, the retractable microneedle drug-eluting balloon dilation catheter proposed in this solution firstly utilizes a spirally wound elastic substrate 31, in conjunction with the synergistic design of the receiving sleeve 211 and protective side wings 32, to provide stable vertical support and a flexible buffer interface for the microneedle puncture unit 21 during balloon expansion. This ensures that the microneedle assembly always maintains a puncture posture perpendicular to the blood vessel wall and effectively shields the sharp edges of rigid components, significantly improving the catheter's passability and safety in complex and tortuous blood vessels. At the same time, the stretching properties of the elastic substrate 31 also enable automatic adjustment of the distribution density of the microneedle 2122 array.

[0083] Secondly, it utilizes the sudden instability characteristics of the arched elastic sheet 213 to convert the static extrusion pressure of the balloon into the instantaneous ejection kinetic energy of the microneedle assembly, thereby overcoming the surface tension of the hard calcified plaque to achieve armor penetration; and further, it is combined with the "rigid-flexible-rigid" segmented receiving sleeve 211 with stiffness cascade characteristics to realize a graded progressive puncture mode: that is, in the initial stage, high stiffness is used to maintain a fixed length ejection to penetrate the surface layer, and in the subsequent stage, the compression deformation of the axially expandable section 2112 is used to dynamically increase the extension length of the microneedle 2122, so that the microneedle 2122 can adaptively adjust the puncture depth according to the actual resistance and thickness of the lesion tissue.

[0084] Finally, this solution further achieves strict fluid control based on stroke position triggering through a mechanical interlocking mechanism that matches the morphology of the clamping protrusion 221 with the inner wall of the receiving sleeve 211. This ensures that the drug flow channel is only opened after the microneedle 2122 has fully penetrated the lesion tissue, thus preventing premature drug leakage. At the same time, combined with the conical solid tip and lateral injection hole design of the microneedle 2122, it ensures high-strength hardening of the needle tip while preventing tissue core extraction blockage and achieving multi-directional radial diffusion of the drug in deep lesion tissue, thereby achieving efficient, safe and uniform drug delivery.

[0085] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

[0086] Furthermore, it should be noted that the accompanying drawings are intended to schematically illustrate the basic structure and operating principle of the invention, and are not drawn to strict engineering scale. To more clearly demonstrate the microscopic fit between the microneedle assembly, the arched elastic sheet, and the internal components of the receiving sleeve, the dimensions, thicknesses, and gaps of relevant parts in the drawings may be exaggerated or enlarged proportionally, and do not represent the actual physical dimensions of the product. Therefore, those skilled in the art, when implementing this invention, should combine the logic described in the specification with the conventional tolerance requirements of existing mechanical manufacturing processes to conduct reasonable engineering design of the specific dimensions and fit between each component, and should not be limited by the visual scale shown in the drawings.

[0087] Furthermore, the directional terms such as above, below, left, right, and center used in this specification are merely for clarity of description and are not intended to limit the scope of implementation of this invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, shall also be considered within the scope of implementation of this invention.

Claims

1. A retractable microneedle drug-eluting balloon dilation catheter, comprising a catheter assembly and a balloon body located at the distal end of the catheter assembly, characterized in that, It also includes multiple microneedle puncture units located outside the balloon body; The microneedle puncture unit includes a receiving sleeve, a microneedle assembly, and an elastic drive. The receiving sleeve has openings at both the top and bottom. A sealing cap is provided at the top of the receiving sleeve, and a puncture slit is provided at the middle position of the sealing cap. The microneedle assembly is slidably fitted inside the receiving sleeve. The elastic drive is connected to the bottom opening of the receiving sleeve and to the bottom of the microneedle assembly. When the balloon expands and deforms, the elastic drive is squeezed to cause elastic deformation, which drives the puncture end of the microneedle assembly to pass through the puncture slit and eject. A connecting base is provided between the multiple microneedle puncture units and the balloon body, and the multiple microneedle puncture units are connected to the balloon body through the connecting base. When the balloon body is inflated, the connecting base extends and deforms as the surface area of ​​the balloon body increases. The microneedle assembly includes a sliding block and a microneedle disposed on the upper part of the sliding block. The microneedle is hollow inside and is connected to the infusion channel inside the catheter assembly through a retractable hose inserted inside the sliding block. An elastic valve chamber is formed in the middle of the retractable hose located on the sliding block. The elastic valve chamber achieves on / off switching through radial elastic deformation. The sliding block has mounting holes on both sides that extend laterally into the elastic valve cavity. A clamping protrusion is elastically installed in the mounting hole, and one end of the clamping protrusion abuts against the elastic valve cavity. A guide groove extending axially is provided on the inner wall of the receiving sleeve corresponding to the position of the clamping protrusion. A release recess with a depth greater than the groove depth and a smooth transition is provided at the far end of the guide groove. When the clamping protrusion abuts against the bottom of the guide groove, it presses the elastic valve cavity inward to close it. When the clamping protrusion slides into the release recess, it releases the pressure on the elastic valve cavity, allowing it to elastically return to conduction.

2. The retractable microneedle drug-eluting balloon dilation catheter according to claim 1, characterized in that: The elastic drive component includes an arched elastic sheet whose bottom is connected to the surface of the balloon body via a connecting base. The arched elastic sheet has an initial state in which it is concave away from the direction of the sealing cap, and a working state in which it is convex towards the direction of the sealing cap after being flipped over. When the balloon body expands and deforms and squeezes the arched elastic sheet to a preset threshold, the arched elastic sheet undergoes a sudden deformation and flips over from the initial state to the working state.

3. The retractable microneedle drug-eluting balloon dilation catheter according to claim 2, characterized in that: The bottom of the sliding block is connected to the top of the arched elastic sheet, and the outer peripheral wall of the sliding block slides in fit with the inner wall of the receiving sleeve.

4. The retractable microneedle drug-eluting balloon dilation catheter according to claim 2, characterized in that: The connecting base includes an elastic substrate spirally wound around the outside of the balloon body. The elastic substrate undergoes circumferential tensile deformation as the balloon body expands. The receiving sleeves of the microneedle puncture unit are equidistantly distributed along the extension direction of the elastic substrate, and clearance perforations are opened on the elastic substrate corresponding to the receiving sleeves. The arched elastic sheet is connected to the surface of the balloon body through the clearance perforations.

5. The retractable microneedle drug-eluting balloon dilation catheter according to claim 4, characterized in that: The elastic substrate has upwardly extending protective wings on both sides in its width direction. The tops of the two protective wings are close to each other and have an elastic contraction tendency. The two protective wings and the elastic substrate together form a semi-closed receiving groove. The receiving sleeve is embedded in the receiving groove, and the height of the outer surface of the protective wings is flush with the top sealing cap of the receiving sleeve, so as to form a protective enclosure for the microneedle puncture unit when the balloon is not inflated.

6. The retractable microneedle drug-eluting balloon dilation catheter according to claim 2, characterized in that: The receiving sleeve comprises, from top to bottom, a rigid guide section, an axially expandable section, and a rigid connecting section along its axial direction. The sealing cap is disposed at the top of the rigid guide section. The elastic drive member is connected to the bottom of the rigid connecting section and directly contacts the surface of the balloon body. The axially expandable section is located between the rigid guide section and the rigid connecting section. The guide groove is formed on the inner wall of the rigid connecting section. The pressure of the axially expandable section during axial compression deformation is greater than the pressure of the arched elastic sheet during sudden deformation, so that the arched elastic sheet preferentially undergoes sudden deformation.

7. The retractable microneedle drug-eluting balloon dilation catheter according to claim 1, characterized in that: The catheter assembly includes a multi-lumen tube with a Luer seat at one end away from the balloon body. Inside the multi-lumen tube, along its axial direction, there are an inflation chamber for inflating the balloon body, a guidewire chamber for the guidewire to pass through, and an infusion channel for delivering medication.

8. The retractable microneedle drug-eluting balloon dilation catheter according to claim 1, characterized in that: The top of the sealing cap is arc-shaped, the puncture tip of the microneedle is a conical tip structure, and multiple lateral injection holes are opened on the side wall of the microneedle near the puncture tip. The lateral injection holes are located below the conical tip structure and are connected to the internal hollow flow channel of the microneedle. A drug coating is also coated on the outer surface of the puncture end of the microneedle.

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