Targeted drug release type cardiovascular stent system for preventing vascular restenosis

Abstract

The invention discloses a targeted drug release type cardiovascular stent system for preventing vascular restenosis, and belongs to the technical field of interventional medical instruments. Comprising a stent skeleton matched with a coronary artery lumen, a micro-fluidic drug storage bin assembly integrally embedded in the stent skeleton, an intelligent driving assembly correspondingly assembled in a micro-fluidic channel and a targeted release mechanism arranged in the stent skeleton, the micro-fluidic drug storage bin assembly comprises a plurality of independently sealed drug storage bins and corresponding micro-fluidic channels, and the intelligent driving assembly achieves sequential unlocking according to the vascular repair stage through a Venturi tube, a body temperature response type diameter adjusting piece, a sequential degradation sealing piece and an elastic self-reset blocking sealing piece, dynamically adjusts the drug release amount along with the body temperature gradient, and achieves the purpose of repairing the blood vessel. And the liquid medicine is directionally released to a diseased region through the array microtube. The full-period staged precise drug delivery can be realized, the unbalance and unexpected release of the drug are avoided, and the effect and clinical reliability of the stent for preventing the vascular restenosis are improved.

Description

Technical Field

[0001] This invention relates to the field of interventional medical device technology, and in particular to a targeted drug-release cardiovascular stent system for preventing restenosis. Background Technology

[0002] Cardiovascular stent technology mainly refers to implantable medical devices used to support the lumen of coronary arteries. This type of technology has the core function of physically opening up narrowed blood vessels. Some stents have a drug coating on their surface, which achieves basic anti-intima hyperplasia intervention through natural drug diffusion. It is a conventional interventional technique that combines passive support with basic drug release.

[0003] Existing technologies generally suffer from limitations in achieving sequential drug release according to different stages of vascular repair, leading to accidental or delayed drug release. They can only achieve fixed-dose, fixed-flow-rate drug release, resulting in poor targeting and compatibility. They are also prone to causing excessively high local drug concentrations or insufficient drug delivery, and it is difficult to avoid ineffective drug release under non-target conditions. They cannot provide full-cycle, precise prevention of vascular restenosis, and the overall controllability of drug release and therapeutic effect are insufficient to meet clinical needs. Summary of the Invention

[0004] The purpose of this invention is to provide a targeted drug-release cardiovascular stent system for preventing restenosis, thereby solving the aforementioned technical problems.

[0005] To achieve the above objectives, the present invention provides a targeted drug-release cardiovascular stent system for preventing restenosis, comprising: A stent framework that fits the lumen of the coronary arteries; A microfluidic drug reservoir assembly is integrated and embedded inside the support frame. The microfluidic drug reservoir assembly includes multiple independent and sealed drug reservoirs and multiple microfluidic channels that are connected one-to-one. The multiple drug reservoirs are respectively equipped with drug solutions with different functions. The intelligent drive assembly comprises multiple sets, each corresponding to one another, assembled within each microfluidic channel. Each set of intelligent drive assemblies includes a Venturi tube, a diameter adjustment component made of shape memory alloy, a degradation seal, and a plugging seal. The Venturi tube is correspondingly assembled within the microfluidic channel. The diameter adjustment component is arranged radially within the microfluidic channel, with its output end correspondingly arranged on the Venturi tube to adjust the drug impact force. The degradation seal is sealed against the inlet end of the Venturi tube, and the plugging seal is sealed against the outlet end of the Venturi tube to control its opening and closing based on the drug impact force. A targeted release mechanism is assembled inside the stent skeleton, and the input end of the targeted release mechanism is connected to the output end of the venturi tube. The output end of the targeted release mechanism includes multiple arrayed microtubes, each of which extends out of the stent skeleton to release the drug solution in a directional manner.

[0006] Preferably, the support frame includes an internal tube and an external support mesh, the external support mesh being coaxially sleeved outside the internal tube, and the external support mesh being a hollow mesh support structure. The microfluidic drug storage assembly, the intelligent drive assembly, and the targeted release mechanism are all arranged between the internal tube and the external support mesh.

[0007] Preferably, the support frame further includes a support airbag, which is a ring structure. There are two support airbags, which are coaxially sleeved at both ends of the internal tube and connected to each other by an air tube. One of the support airbags is connected to an inflation tube, and the inflation end of the inflation tube extends out of the internal tube so that both can be inflated by a detachably connected pressure inflatable balloon.

[0008] Preferably, the drug reservoir has an arc-shaped structure and is fixedly attached to the internal tube. The drug reservoir is located between the two supporting airbags. The outer edge of the drug reservoir is fixedly connected to the inner side of the external support net so that the external support net can move radially. The microfluidic channel has an arc-shaped structure and is arranged to fit the outer wall of the internal tube, and its outer edge is spaced apart from the external support net.

[0009] Preferably, the drug storage compartment is provided with a drug injection pipe, and the multiple drug injection pipes are arranged along the axial direction of the internal passage pipe, and the end of each drug injection pipe is arranged close to the end of the internal passage pipe, so as to replenish the drug solution respectively.

[0010] Preferably, the output end of the microfluidic channel is integrally fixed with an output end head, the output end head is arranged radially along the internal tube, and the output end head is connected to the input end of the targeted release mechanism.

[0011] Preferably, the venturi tube includes an inlet section, an outlet section, and a throat section. The ends of the inlet section and the outlet section are tightly fitted and fixed to the inner wall of the microfluidic channel. The throat section is an elastic structure that can extend along its axial direction, and its two ends are respectively hermetically connected to the inlet section and the outlet section. The diameter adjustment element is arranged between the throat section and the wall of the microfluidic channel to adjust the diameter of the throat section based on changes in body temperature.

[0012] Preferably, both the microfluidic drug reservoir assembly and the intelligent drive assembly are thermally conductive structures, the degradable seal is a phase-sequential self-degradable sealing membrane that automatically degrades based on the vascular repair phase cycle, and the sealing element is an elastic self-resetting tension membrane that adaptively adjusts the opening degree according to the impact force of the drug solution, and the opening degree is proportional to the impact force, so as to realize the dynamic control of drug dosage with body temperature gradient.

[0013] Preferably, the plurality of drug storage compartments are respectively filled with drug solutions that match the symptoms of the plurality of vascular repair stages, the elongation length of the plurality of diameter adjustment members is respectively matched with the temperature change range of the symptoms of the plurality of vascular repair stages, and the opening timing of the plurality of stage-sequential self-degrading sealing films corresponds synchronously with the repair stage.

[0014] Preferably, the targeted release mechanism includes a connecting tube and a diffuser plate. The connecting tube is horn-shaped and communicates with the output end. The horn opening of the connecting tube is integrally fixed with the diffuser plate. The diffuser plate has an arc-shaped structure and its outer edge is fitted to the inner side of the external support net. The diffuser plate is hollow inside, and the microtube array is arranged at the outer edge of the diffuser plate and inserted into the mesh holes of the external support net to spray the drug solution onto the blood vessel wall through multiple microtubes.

[0015] Therefore, the beneficial effects of the targeted drug-release cardiovascular stent system for preventing restenosis described above are as follows: 1. By designing the seal at the inlet end of the Venturi tube as a phased, time-sequential, self-degrading sealing membrane, it automatically degrades and unlocks according to the vascular repair phase cycle. At the same time, combined with the heat-conducting structure of the microfluidic drug reservoir component and the intelligent drive component, it achieves secondary precise control of the drug release process by body temperature. The drug delivery pathway is only officially opened when the degrading sealing membrane has completed phase degradation and the intraluminal body temperature matches the symptom temperature range of the corresponding repair phase. This avoids the phase mis-release problem that is prone to occur in traditional stents with single temperature triggering. It accurately matches the physiological time sequence of vascular repair and achieves dual targeted initiation of phase sequence + body temperature pathology, ensuring the accuracy of drug release timing and clinical suitability.

[0016] 2. Utilizing the characteristic of shape memory alloy diameter adjustment components changing with body temperature gradients, the diameter of the venturi throat section is simultaneously adjusted, altering the cross-sectional area and flow rate of the drug solution. Simultaneously, the outlet end sealing component is designed as an elastic self-resetting tension membrane that adaptively adjusts the opening degree based on the impact force of the drug solution, with the opening degree being proportional to the impact force. This allows for dynamic control of the drug dosage based on the temperature gradient, flexibly adjusting the dosage according to the severity of symptoms at different stages of vascular repair. This enables dynamic and precise drug delivery, providing minimal prevention for mild cases and sufficient treatment for severe cases. It avoids tissue damage caused by drug overdose and provides sufficient medication promptly when the condition worsens, improving the accuracy and effectiveness of restenosis prevention.

[0017] 3. The microfluidic drug storage module, intelligent drive module, and targeted release mechanism are integrated and embedded between the internal tubes and external support network of the stent skeleton. Combined with the support balloon, this achieves minimally invasive stent implantation and positioning support. The external support network adopts a hollow mesh structure, with the microfluidic channels and microtubes of the targeted release mechanism interspersed within the mesh holes. The overall structure is compact and adaptable to the coronary artery lumen. The radially movable design at both ends of the support balloon and the intermediate arrangement with the vessel wall ensure the stability of the stent support while avoiding hard friction between the stent and the vessel wall, reducing the risk of postoperative vascular injury, and improving the safety and comfort of stent implantation.

[0018] 4. By setting up multiple independent and sealed drug storage compartments, each containing medications appropriate for different stages of vascular repair, a phased and multi-dimensional approach to restenosis prevention is achieved. Simultaneously, each drug storage compartment is equipped with a medication injection tube arranged axially along the internal cannula, with a pre-reserved replenishment interface near the cannula end. This allows for flexible replenishment of medications via minimally invasive intervention based on the patient's actual postoperative recovery, adapting to the entire vascular repair cycle's medication needs. Furthermore, the independent sealing of each storage compartment avoids cross-contamination between different medications, ensuring the purity and effectiveness of medication at each stage, and achieving a long-lasting, iterative, and highly adaptable medication delivery guarantee throughout the entire cycle.

[0019] 5. The targeted release mechanism adopts a structure in which a trumpet-shaped connecting tube and an arc-shaped hollow diffuser are integrally fixed. The microtube array is arranged on the outer edge of the diffuser and inserted into the mesh of the external support net. After the drug solution is output through the Venturi tube, it is evenly introduced into the diffuser through the connecting tube, and then directionally sprayed onto the blood vessel wall through the microtubes. This optimizes the delivery and diffusion path of the drug solution and avoids the problems of excessively high local concentration or uneven distribution, achieving uniform, directional, and full coverage spraying of the drug solution on the blood vessel wall. At the same time, the microtubes inserted into the mesh of the support net ensure the accuracy of targeted release without damaging the support structure of the external support net, further improving the overall mechanical properties and therapeutic effect of the stent.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 A three-dimensional structural diagram of a targeted drug-release cardiovascular stent system for preventing restenosis provided by the present invention; Figure 2 for Figure 1 A sectional view; Figure 3 This is a schematic diagram illustrating the working principle of the intelligent drive component in a targeted drug-release cardiovascular stent system for preventing restenosis, as provided by the present invention.

[0022] Figure Labels 1. Scaffold frame; 11. Internal tube; 12. External support net; 13. Support airbag; 14. Inflation tube; 2. Microfluidic drug reservoir assembly; 21. Drug reservoir; 211. Drug injection tube; 22. Microfluidic channel; 221. Output end; 3. Intelligent drive assembly; 31. Venturi tube; 311. Inlet section; 312. Outlet section; 313. Throat section; 32. Diameter adjustment component; 33. Degradable seal; 34. Sealing seal; 4. Targeted release mechanism; 41. Microtube; 42. Connecting tube; 43. Diffuser plate. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0024] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0025] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] Traditional cardiovascular stents can only provide physical support for narrowed blood vessels. Drug-eluting stents generally suffer from problems such as unpredictable drug release, insufficient targeting, limited drug loading, and unsustainable replenishment. They cannot meet the medication needs of different stages of vascular repair. In addition, the stent structure is prone to mechanical stimulation of the vascular intima, resulting in poor prevention of restenosis and difficulty in guaranteeing the safety and effectiveness of long-term implantation.

[0027] Based on the above analysis, this invention is designed. (See appendix.) Figures 1-3 A targeted drug-release cardiovascular stent system for preventing restenosis, comprising: Stent framework adapted to the lumen of coronary arteries 1; The microfluidic drug storage assembly 2 is integrated and embedded inside the support frame 1. The microfluidic drug storage assembly 2 includes multiple independent and sealed drug storage chambers 21 and multiple microfluidic channels 22 that are connected one-to-one. The multiple drug storage chambers 21 are respectively equipped with drug solutions with different functions. The intelligent drive components 3 are assembled one-to-one in each microfluidic channel 22. Each intelligent drive component 3 includes a venturi tube 31, a diameter adjustment component 32 made of shape memory alloy, a degradation seal 33, and a plugging seal 34. The venturi tube 31 is assembled in the microfluidic channel 22. The diameter adjustment component 32 is arranged radially inside the microfluidic channel 22 and its output end is arranged on the venturi tube 31 to adjust the impact force of the drug liquid. The degradation seal 33 is sealed and attached to the inlet end of the venturi tube 31, and the plugging seal 34 is sealed and attached to the outlet end of the venturi tube 31 to control its opening and closing based on the impact force of the drug liquid. The targeted release mechanism 4 is assembled inside the support frame 1, and the input end of the targeted release mechanism 4 is connected to the output end of the venturi tube 31. The output end of the targeted release mechanism 4 includes multiple arrayed microtubes 41, which extend out of the support frame 1 to release the drug solution in a directional manner.

[0028] This invention relates to a specific embodiment of a stent framework 1. The stent framework 1 includes an internal tube 11 and an external support net 12. The external support net 12 is coaxially sleeved outside the internal tube 11 and has a perforated mesh support structure. The microfluidic drug reservoir component 2, the intelligent drive component 3, and the targeted release mechanism 4 are all arranged between the internal tube 11 and the external support net 12. The stent framework 1 adopts a structure in which the internal tube 11 and the external perforated mesh support net 12 are coaxially sleeved, integrating the microfluidic drug reservoir component 2, the intelligent drive component 3, and the targeted release mechanism 4 between the internal tube 11 and the external support net 12. This structure not only ensures effective physical support for the coronary artery lumen with the external support net 12, but also provides dedicated installation space for each internal functional component. This achieves integrated support structure and drug release functional components, improving the overall compactness and space utilization of the stent structure.

[0029] In the above embodiment, the stent frame 1 further includes a support balloon 13. The support balloon 13 has a ring-shaped structure, and there are two support balloons 13, which are coaxially sleeved at both ends of the internal tube 11. The two support balloons 13 are connected by an air tube. One of the support balloons is connected to an inflation tube 14. The inflation end of the inflation tube 14 extends out of the internal tube 11 to inflate both balloons using a detachably connected pressure inflatable balloon. The stent frame 1 is provided with ring-shaped support balloons 13. The two support balloons 13 are coaxially sleeved at both ends of the internal tube 11 and connected by an air tube. One of the support balloons is connected to an inflation tube 14. The inflation end of the inflation tube 14 extends out of the internal tube 11 to cooperate with the pressure inflatable balloon to complete synchronous inflation. This can achieve reliable positioning of both ends of the stent after implantation, prevent the stent from shifting in the blood vessel, and at the same time, the end balloons form flexible support, reducing the mechanical stimulation of the stent on the vascular intima, improving the stability and vascular compatibility of the stent after implantation. The inflation control method is simple and highly controllable.

[0030] In a specific embodiment of the present invention, the drug storage chamber 21 has an arc-shaped structure and is fixedly attached to the internal tube 11. The drug storage chamber 21 is located between two supporting airbags 13. The outer edge of the drug storage chamber 21 is fixedly connected to the inner side of the external support net 12 so that the external support net 12 can move radially. The microfluidic channel 22 has an arc-shaped structure and is arranged to fit the outer wall of the internal tube 11, and its outer edge is spaced apart from the external support net 12. The drug reservoir 21 is fixed to the internal tube 11 with an arc-shaped structure and is located between the two support balloons 13. Its outer edge is fixedly connected to the inner side of the external support net 12. This ensures that the drug reservoir 21 is firmly installed and allows the two ends of the external support net 12 to have radial mobility. At the same time, it reduces the support force in the middle part and avoids the stent from excessively compressing and damaging the vascular intima. The microfluidic channel 22 is arranged with an arc-shaped structure to fit the outer wall of the internal tube 11 and its outer edge is spaced apart from the external support net 12. This makes full use of the internal space of the stent and provides a stable and safe flow channel environment for drug delivery, improving the rationality of the overall structure and the safety of use.

[0031] In the above embodiments, each drug reservoir 21 is provided with a drug injection tube 211. Multiple drug injection tubes 211 are arranged axially along the internal conduit 11, with the end of each tube close to the end of the internal conduit 11, to replenish the drug solution separately. The arrangement of multiple drug injection tubes 211 along the axial direction of the internal conduit 11 with their ends close to the end of the internal conduit 11 allows for independent replenishment of the drug solution in each drug reservoir 21, meeting the continuous medication needs at different stages of vascular repair. The axial arrangement adapts to the overall structure of the stent, making fluid replenishment convenient and non-interfering, extending the drug action period of the stent system, and improving the long-term effectiveness of treatment to prevent restenosis.

[0032] Specifically, the multiple drug injection tubes 211 and the inflation tube 14 all have rubber sealing structures. During inflation or fluid replenishment, they can be punctured and opened by instruments. After the operation, they can automatically close and seal due to the elasticity of the rubber itself. This not only meets the needs of minimally invasive interventional operations for stent implantation positioning and subsequent drug replenishment, but also effectively prevents blood backflow, drug leakage, and blockage of the tubing lumen. It ensures the airtightness and patency of the inflation and drug injection tubes, maintains the stable support state of the support balloon and the sealed drug storage environment of the drug reservoir, and improves the convenience of clinical use and long-term reliability of the stent system.

[0033] In the above embodiment, the output end of the microfluidic channel 22 is integrally fixed with an output end 221, which is arranged radially along the internal tube 11 and connected to the input end of the targeted release mechanism 4. The integral fixing of the output end 221 at the output end of the microfluidic channel 22, with the output end 221 arranged radially along the internal tube 11 and connected to the targeted release mechanism 4, reduces the risk of leakage at the channel connection, ensures a sealed and stable drug delivery path, and simultaneously achieves precise docking between the microfluidic channel 22 and the targeted release mechanism 4, allowing the drug to be efficiently and smoothly delivered to the release site, thus improving the overall stability of the drug delivery system.

[0034] In a specific embodiment of the Venturi tube 31 in this invention, the Venturi tube 31 includes an inlet section 311, an outlet section 312, and a throat section 313. The ends of the inlet section 311 and the outlet section 312 are tightly fitted and fixed to the inner wall of the microfluidic channel 22. The throat section 313 is an elastic structure that can extend along its axial direction, and its two ends are respectively sealed and connected to the inlet section 311 and the outlet section 312. A diameter adjustment member 32 is arranged between the throat section 313 and the wall of the microfluidic channel 22 to adjust the diameter of the throat section 313 based on changes in body temperature. It ensures a secure overall installation and good flow channel sealing. The throat section 313 adopts an axially extendable elastic structure and is sealed at both ends. It can work with the diameter adjustment component 32 to achieve flexible contraction and expansion of the tube diameter, and also prevent drug leakage. The diameter adjustment component 32 can precisely adjust the diameter of the throat section 313 according to changes in body temperature, thereby stabilizing the drug flow rate and impact pressure. The overall structure is tightly connected and deforms smoothly without jamming, improving the accuracy of drug release control and operational stability of the stent system.

[0035] In the above embodiments, both the microfluidic drug reservoir component 2 and the intelligent drive component 3 are thermally conductive structures. The degradable seal 33 is a phase-sequential self-degrading sealing membrane that automatically degrades based on the vascular repair phase cycle. The occlusion seal 34 is an elastic self-resetting tension membrane that adaptively adjusts its opening degree according to the impact force of the drug solution, and its opening degree is proportional to the impact force, thereby achieving dynamic control of drug dosage with body temperature gradient. The degradable seal 33 is a phase-sequential self-degrading sealing membrane that can automatically degrade and unlock during the vascular repair phase. The occlusion seal is an elastic self-resetting tension membrane that can adaptively adjust its opening degree according to the impact force of the drug solution, and its opening degree is proportional to the impact force, enabling precise and controllable release of the drug solution while avoiding drug leakage and accidental release, ensuring the stability of the stent during service, improving the practicality and clinical adaptability of the stent system, and meeting the needs of interventional treatment.

[0036] Specifically, the phased, time-sequential self-degrading sealing membrane uses medical biodegradable polymer films with different degradation rates. Specifically, it comprises graded degradation materials such as polylactic acid (PLA), polyglycolic acid (PGA), and polycaprolactone (PCL) with controlled molecular weight and copolymerization ratios. When implanted in the human body at 37°C, these membranes gradually degrade via hydrolysis. By adjusting the copolymerization ratio, crosslinking density, and membrane thickness, four degradation cycles are precisely set: 0–7 days, 8–30 days, 31–180 days, and 181–365 days. Each stage of the sealing membrane exhibits a fixed hydrolysis sequence due to differences in material formulation, sequentially undergoing polymer main chain breakage, membrane dissolution and damage, and eventual permeability. This unlocks the corresponding Venturi tube inlet channels according to the vascular repair sequence, requiring no electrical control or external triggering. It achieves phased, time-sequential opening solely through the intrinsic degradation characteristics of the materials, while also possessing excellent biocompatibility. The membrane exhibits controllable degradation within the body and is an elastic self-resetting tension membrane. It utilizes a medical-grade linear elastic polymer film, specifically a biocompatible modified medical silicone rubber or aliphatic polyurethane elastic membrane. A cross-shaped / I-shaped micro-slit structure is pre-fabricated at the center of the membrane. Its working principle relies on the material's constant elastic modulus to maintain an initial sealed state. When the drug solution output from the venturi tube impacts the membrane surface, the membrane undergoes elastic deformation under pressure load, causing the micro-slits to gradually expand and form an opening. Due to the linear deformation characteristics of this elastic membrane, the greater the impact force of the drug solution, the greater the deformation amplitude of the membrane and the micro-slit opening increase linearly and synchronously. When the impact force weakens or disappears, the membrane autonomously contracts and resets itself using its own elastic recovery force, re-closing the micro-slits and restoring the sealed state. This precisely achieves dynamic adjustment of the opening size according to the gradient of the drug solution impact force, and the material exhibits no fatigue deformation, meeting the requirements for long-term service within blood vessels.

[0037] In the above embodiments, multiple drug reservoirs 21 contain drug solutions matched to the symptoms of multiple vascular repair stages. The extension lengths of multiple diameter adjustment components 32 are matched to the temperature variation ranges of the symptoms in each of the multiple vascular repair stages. The opening timing of the multiple stage-sequential self-degrading sealing membranes corresponds synchronously with the repair stages. The multiple drug reservoirs 21 contain drug solutions matched to the symptoms of each stage of vascular repair. The extension lengths of the diameter adjustment components 32 are adapted to the temperature variation ranges of the symptoms in each stage. The opening timing of the stage-sequential self-degrading sealing membranes corresponds synchronously with the vascular repair stages. These three elements work together to achieve precise, staged drug delivery, effectively blocking the causes of restenosis, improving the targeting and compatibility of drug delivery, avoiding drug waste and misrelease, ensuring the orderly release of drug solutions according to the repair stages, enhancing the clinical compatibility and practicality of the stent system, further improving the stent system's effect in preventing vascular restenosis, and improving the overall reliability of treatment and prevention.

[0038] Specifically, the diameter adjustment component 32 is a medical-grade nickel-titanium shape memory alloy tension spring, consisting of two symmetrically arranged springs. Through heat treatment, its phase transformation temperature is precisely set to match the symptom temperature range of each stage of vascular repair. Utilizing the shape memory effect, it achieves temperature-responsive deformation: when the temperature at the lesion site is low, the spring remains in a shorter, contracted state, resulting in less compression of the Venturi tube throat and a larger flow channel diameter. As the local temperature rises, the nickel-titanium alloy undergoes a martensitic-to-austenitic crystal structure transformation, and the spring gradually elongates with increasing temperature, with greater elongation at higher temperatures. This elongation pushes inward, contracting the Venturi tube throat diameter and increasing the drug flow rate and impact force. When the temperature decreases, the alloy undergoes a reverse phase transformation, and the spring shortens and returns to its original position, correspondingly expanding the flow channel. It can adaptively adjust the drug flow cross-section according to the body temperature gradient without external drive, exhibiting excellent biocompatibility and long-term in vivo deformation stability.

[0039] Specifically, the stent system achieves targeted drug delivery throughout the entire vascular repair cycle through phased and precise drug release control. Relying on the synergistic cooperation of various structures, it completes the prevention and intervention of vascular restenosis in four stages. Each stage achieves precise drug release through temperature triggering and pressure control. The specific working principles of each stage are as follows: There are four drug storage compartments, and the intelligent drive component 3 is divided into four groups accordingly; Phase 1: Postoperative acute thrombosis prevention period (0-7 days); This stage is the acute phase of vascular repair, requiring rapid inhibition of thrombus formation and protection of the vascular endothelium. Corresponding symptoms include early postoperative mechanical damage to the vascular endothelium, mild inflammatory response, and local body temperature maintained at 37.0–37.5°C. The first drug reservoir is loaded with the antiplatelet drug ticagrelor, with a stage cycle of 0–7 days. Upon stage initiation, the stage-sequential self-degrading membrane within the first intelligent drive component completes degradation, releasing the venturi tube inlet blockage. The diameter adjustment component within the first intelligent drive component expands and contracts with body temperature, adjusting the venturi tube throat diameter, changing the drug flow rate and impact force, thereby controlling the opening of the occlusion membrane to achieve flow regulation, and further regulating the drug spraying speed. The drug is sprayed onto the vessel wall through microtube 41, achieving acute thrombosis prevention, avoiding early postoperative thrombus formation, and laying the foundation for subsequent repair.

[0040] Phase 2: Postoperative inflammation control period (8-30 days); This stage is the intimal inflammation resolution period, with corresponding symptoms including inflammatory edema of the vascular intima, a small amount of inflammatory cell infiltration, and local body temperature maintained at 37.6–38.2℃. The second drug reservoir is loaded with the anti-inflammatory drug dexamethasone, and the stage cycle is 8–30 days. After the stage starts, the self-degrading membrane in the second intelligent drive component is completely degraded, and the diameter of the venturi tube throat in the second intelligent drive component is adjusted by the diameter adjustment component, thereby regulating the flow rate of the drug solution. The drug is sprayed onto the blood vessel wall through the diffuser structure, precisely inhibiting intimal inflammation, blocking intimal hyperplasia caused by the inflammatory response, avoiding vascular stenosis caused by the spread of inflammation, and creating an inflammatory-free environment for subsequent endothelial repair.

[0041] Phase 3: Smooth muscle proliferation inhibition period (31–180 days); This stage is a high-incidence period for abnormal proliferation of vascular wall smooth muscle, with symptoms including excessive proliferation of smooth muscle cells, a tendency for luminal narrowing, and local body temperature stabilizing at 36.8–37.4°C. The third drug storage chamber is loaded with the anti-proliferative drug paclitaxel, with a stage cycle of 31–180 days. The diameter adjustment component in the third intelligent drive assembly adjusts the venturi tube throat diameter, and the drug is evenly sprayed through the diffusion structure, precisely acting on the lesion site to inhibit abnormal smooth muscle proliferation and block the core inducing factor of vascular restenosis.

[0042] Phase 4: Endothelial repair consolidation period (181–365 days); This stage is a critical period for vascular endothelial repair. Symptoms include incomplete endothelial cell coverage and incomplete repair, with local body temperature maintained at 36.5–36.9°C. The fourth drug storage chamber contains VEGF, a drug that promotes endothelial repair, with a stage cycle of 181–365 days. The diameter adjustment component in the fourth intelligent drive assembly adjusts the venturi tube throat diameter, and the drug solution is directionally sprayed through microtube 41 to promote complete endothelial cell coverage of the blood vessel wall, complete vascular endothelial repair, consolidate the previous treatment effect, prevent restenosis, and achieve long-term preventive effect.

[0043] In a specific embodiment of the targeted release mechanism 4 in this invention, the targeted release mechanism 4 includes a connecting tube 42 and a diffuser plate 43. The connecting tube 42 is horn-shaped and communicates with the output end 221. The horn opening of the connecting tube 42 is integrally fixed with the diffuser plate 43. The diffuser plate 43 has an arc-shaped structure and its outer edge is attached to the inner side of the external support net 12. The diffuser plate 43 is hollow inside, and microtubes 41 are arranged in an array at the outer edge of the diffuser plate 43 and inserted into the mesh holes of the external support net 12 so as to spray the drug solution onto the blood vessel wall through multiple microtubes 41. The targeted release mechanism 4 is connected to the outlet end of the Venturi tube 31 through the flared connecting tube 42, which effectively reduces the flow resistance of drug delivery. The flared opening of the connecting tube 42 is integrally fixed with the arc-shaped hollow diffuser 43. The outer edge of the diffuser 43 is arranged in close contact with the inner side of the external support net 12. The array of microtubes 41 are inserted into the mesh holes of the external support net 12, which can evenly disperse and directionally spray the drug solution onto the blood vessel wall. While improving the range of action and uniformity of drug release, the structure is compact and fits the overall layout of the stent, further enhancing the accuracy and therapeutic effect of targeted drug delivery to the coronary stent.

[0044] The working principle of the targeted drug-release cardiovascular stent system for preventing restenosis of the present invention is as follows: S1. The stent system is implanted into the coronary artery lesion site and fixed and supported to ensure that the stent is stably deployed to the target area within the blood vessel; S2. Each time-series self-degradable sealing membrane hydrolyzes and degrades sequentially in the physiological environment of the body according to the preset vascular repair stage cycle, gradually opening the corresponding drug flow channel inlet. S3. The temperature of the local vascular symptoms is conducted through the heat-conducting structure, which drives the diameter adjustment component to expand and contract, changing the size of the throat diameter of the flow channel, thereby regulating the flow rate and impact pressure of the drug solution. S4. The elastic self-resetting sealing membrane at the outlet of the liquid medicine impact has an opening that adapts to the magnitude of the liquid medicine impact force. The larger the impact force, the larger the opening. When there is no impact, it automatically closes, realizing dynamic adjustment of the liquid medicine gradient. S5. The regulated drug solution is fed into the targeted release structure and acts uniformly and directionally on the lesion site of the blood vessel wall through the array-type output pipeline; S6. The system releases corresponding functional drugs in stages according to the entire vascular repair cycle sequence, and sequentially completes continuous interventions such as antithrombosis, anti-inflammation, inhibition of abnormal smooth muscle proliferation, and promotion of endothelial repair. S7. Postoperatively, medication can be replenished to the independent drug storage unit through the reserved fluid replenishment structure to maintain the long-term stable drug release and restenosis prevention function of the stent system.

[0045] In summary, this invention achieves phased, dynamic, and targeted drug delivery throughout the entire vascular repair cycle through the synergistic combination of phased time-sequential degradation unlocking, body temperature-responsive flow regulation, and adaptive elastic opening drug release. It can precisely match the timing and dosage of drug delivery according to the disease characteristics and body temperature changes at different repair stages. At the same time, it relies on an independent drug storage unit and a subsequent fluid replenishment structure to achieve long-term drug delivery. Combined with uniform targeted spraying to act on the diseased vascular wall, it ensures the accuracy and stability of drug delivery, avoids accidental drug release, dose imbalance, and abnormal local concentration. It blocks the inducing factors of vascular restenosis throughout the entire process from thrombosis, inflammatory response, smooth muscle proliferation to endothelial repair. The overall structure is compact and adaptable to coronary intervention implantation scenarios, with excellent biocompatibility and service stability, which greatly improves the reliability and clinical suitability of stent systems in preventing vascular restenosis.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A targeted drug-release cardiovascular stent system for preventing restenosis, characterized in that, include: Stent framework adapted to coronary artery lumen (1); Microfluidic drug storage assembly (2), the microfluidic drug storage assembly (2) is integrated and embedded inside the support frame (1), the microfluidic drug storage assembly (2) includes multiple independent and sealed drug storage chambers (21) and multiple microfluidic channels (22) that are connected one-to-one, and the multiple drug storage chambers (21) are respectively equipped with drug solutions with different functions; The intelligent drive component (3) consists of multiple sets, each corresponding to one another, assembled in each of the microfluidic channels (22). Each set of intelligent drive components (3) includes a venturi tube (31), a diameter adjustment component (32) made of shape memory alloy, a degradation seal (33), and a plugging seal (34). The venturi tube (31) is assembled in the microfluidic channel (22). The diameter adjustment component (32) is arranged radially inside the microfluidic channel (22), and its output end is arranged on the venturi tube (31) to adjust the impact force of the drug solution. The degradation seal (33) is sealed and attached to the inlet end of the venturi tube (31), and the plugging seal (34) is sealed and attached to the outlet end of the venturi tube (31) to control its opening and closing based on the impact force of the drug solution. The targeted release mechanism (4) is assembled inside the stent skeleton (1), and the input end of the targeted release mechanism (4) is connected to the output end of the venturi tube (31). The output end of the targeted release mechanism (4) includes multiple arrayed microtubes (41), and the multiple microtubes (41) extend out of the stent skeleton (1) to release the drug solution in a directional manner.

2. The targeted drug-release cardiovascular stent system for preventing restenosis according to claim 1, characterized in that: The support frame (1) includes an internal tube (11) and an external support net (12). The external support net (12) is coaxially sleeved outside the internal tube (11). The external support net (12) is a hollow mesh support structure. The microfluidic drug storage assembly (2), the intelligent drive assembly (3), and the targeted release mechanism (4) are all arranged between the internal tube (11) and the external support net (12).

3. The targeted drug-release cardiovascular stent system for preventing restenosis according to claim 2, characterized in that: The support frame (1) also includes a support airbag (13), which is a ring structure. There are two support airbags (13) and they are coaxially sleeved at both ends of the internal tube (11). The two support airbags (13) are connected by an air tube. One of the support airbags is connected to an inflation tube (14). The inflation end of the inflation tube (14) extends out of the internal tube (11) so that both can be inflated by a detachably connected pressure inflation balloon.

4. The targeted drug-release cardiovascular stent system for preventing restenosis according to claim 3, characterized in that: The drug storage chamber (21) has an arc-shaped structure and is fixedly attached to the internal tube (11). The drug storage chamber (21) is located between the two support airbags (13). The outer edge of the drug storage chamber (21) is fixedly connected to the inner side of the external support net (12) so that the external support net (12) can move radially. The microfluidic channel (22) has an arc-shaped structure and is arranged in close contact with the outer wall of the internal tube (11), and its outer edge is spaced apart from the external support net (12).

5. A targeted drug-release cardiovascular stent system for preventing restenosis according to claim 4, characterized in that: The drug storage compartment (21) is provided with a drug injection pipe (211). Multiple drug injection pipes (211) are arranged along the axial direction of the internal passage pipe (11), and the end of each drug injection pipe (211) is arranged close to the end of the internal passage pipe (11) to replenish the drug solution.

6. A targeted drug-release cardiovascular stent system for preventing restenosis according to claim 4, characterized in that: The output end of the microfluidic channel (22) is integrally fixed with an output end (221), which is arranged radially along the internal tube (11) and is connected to the input end of the targeted release mechanism (4).

7. A targeted drug-release cardiovascular stent system for preventing restenosis according to claim 6, characterized in that: The targeted release mechanism (4) includes a connecting tube (42) and a diffuser plate (43). The connecting tube (42) is horn-shaped and communicates with the output end (221). The horn opening of the connecting tube (42) is integrally fixed with the diffuser plate (43). The diffuser plate (43) has an arc-shaped structure and its outer edge is attached to the inner side of the external support net (12). The diffuser plate (43) is hollow inside, and the microtubes (41) are arranged in an array at the outer edge of the diffuser plate (43) and inserted into the mesh holes of the external support net (12) so as to spray the drug solution onto the blood vessel wall through multiple microtubes (41).

8. A targeted drug-release cardiovascular stent system for preventing restenosis according to claim 1, characterized in that: The Venturi tube (31) includes an inlet section (311), an outlet section (312), and a throat section (313). The ends of the inlet section (311) and the outlet section (312) are tightly fitted and fixed to the inner wall of the microfluidic channel (22). The throat section (313) is an elastic structure that can extend along its axial direction, and its two ends are respectively sealed to the inlet section (311) and the outlet section (312). The diameter adjustment element (32) is arranged between the throat section (313) and the wall of the microfluidic channel (22) to adjust the diameter of the throat section (313) based on changes in body temperature.

9. A targeted drug-release cardiovascular stent system for preventing restenosis according to claim 8, characterized in that: Both the microfluidic drug storage assembly (2) and the intelligent drive assembly (3) are thermally conductive structures. The degradable seal (33) is a phase-sequential self-degradable sealing membrane that automatically degrades based on the vascular repair phase cycle. The sealing component (34) is an elastic self-resetting tension membrane, and the elastic self-resetting tension membrane adaptively adjusts the opening degree according to the impact force of the drug solution, and its opening degree is proportional to the impact force, so as to realize the dynamic control of drug dosage with body temperature gradient.

10. A targeted drug-release cardiovascular stent system for preventing restenosis according to claim 9, characterized in that: Each of the multiple drug storage compartments (21) contains a drug solution that matches the symptoms of multiple vascular repair stages. The elongation length of each of the multiple diameter adjustment components (32) matches the temperature change range of the symptoms of multiple vascular repair stages. The opening timing of the multiple stage-sequential self-degrading sealing membranes corresponds synchronously with the repair stage.

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