Stent delivery device and stent system comprising the same

Abstract

The present application relates to a stent delivery device and a stent system comprising the same. The stent delivery device comprises a push rod; a force buffer component arranged at the distal end of the push rod, comprising at least one force transmission member, which forms a non-zero angle with the axial center line of the push rod, and the distance between the distal end of the force transmission member and the distal end of the stent delivery device as a whole is less than or equal to the nominal diameter of the stent delivered by the stent delivery device, and is configured such that when the axial pushing force applied to the proximal end of the push rod causes the proximal end of the stent delivery device to move axially by a distance not more than half the axial length of the force transmission member. The stent delivery device of the present application can regulate the pushing force transmitted to the blood vessel wall, so that the force applied to the blood vessel wall during pulling and / or pushing is always within a controllable low force value range, reducing the mechanical stimulation and potential damage risk to the blood vessel wall, and improving the safety of stent implantation.

Description

Technical Field

[0001] This invention belongs to the field of medical devices, specifically relating to a stent delivery device and a stent system including the stent. Background Technology

[0002] Self-expanding stents are widely used in interventional vascular treatment. Relying on their self-expanding properties, they radially expand and become fixed within the vessel lumen after the delivery system is withdrawn, thus maintaining vascular patency and / or guiding blood flow. Typically, a self-expanding stent is inserted proximally (e.g., into the radial or femoral artery) via a delivery system and delivered along the vessel to the lesion site. Upon reaching the target location, the stent is gradually released under the control of the delivery system and stably adheres to the vessel wall using its own radial support force, achieving support and / or blood flow restoration in the lesion area. The delivery system usually consists of a catheter, a pusher, and internal structures (such as guidewires and silicone pads). Its function is to ensure that the stent remains compressed during delivery and is successfully delivered to the target location for stable release. During the procedure, the operator needs to push the internal structures and / or withdraw the catheter to facilitate the gradual release of the stent.

[0003] However, existing delivery systems present certain technical limitations and clinical risks during the delivery of self-expanding stents to the lesion area and their subsequent release. While self-expanding stents expand radially, they typically contract axially to some extent. This contraction effect can cause the distal end of the guidewire or pusher within the delivery system to shift forward, especially during continuous proximal push or catheter retraction. This thrust can be transmitted distally, causing a sudden forward movement of the distal structure of the delivery device. When this distal structure extends beyond the stent itself and contacts the vessel wall, it can cause mechanical irritation and even vascular damage. This phenomenon is particularly pronounced in complex, tortuous vascular environments. Due to the curvature of the vascular structure, the transmission of the pushing force is not linear, and changes in vascular morphology can lead to distal mechanical instability, making it easier for the distal guidewire or delivery device to extend beyond the stent and contact the vessel wall.

[0004] When lesions occur at vascular bifurcation sites, the distal segment of the delivery system that can be anchored to a normal vascular segment is typically short. In such cases, proximal pushing force may cause the distal end of the delivery device to remain close to the vessel wall, or even directly abut against the vessel wall, thereby causing local vascular stress or potential damage. For such complex vascular anatomy, the rigidity of existing delivery systems may exacerbate this problem, making it difficult to stably control the distal structure and thus affecting the accuracy of stent deployment. Furthermore, fluctuations in the distal pushing force of the delivery system may also affect the stability of stent deployment. Small fluctuations in force during the pushing process may be amplified to the distal end, leading to unstable movement of the stent during deployment, affecting stent apposition and the final implantation outcome.

[0005] Therefore, there is a need in the field to develop a stent delivery device and stent system that can reduce the risk of distal vascular puncture during self-expanding stent delivery and reduce vascular stress. Summary of the Invention

[0006] To address the shortcomings of existing technologies, one objective of this invention is to provide a support conveying device, comprising:

[0007] Axially extending push rod;

[0008] A force buffer component is disposed at the distal end of the push rod; the force buffer component includes at least one force transmission member, the force transmission member forming a non-zero angle with the axial center line of the push rod; the distance between the distal end of the force buffer component and the distal end of the entire support conveying device is less than or equal to the nominal diameter of the support conveying device.

[0009] The force buffer component is configured such that when the axial thrust applied to the proximal end of the push rod causes the proximal end of the support conveying device to move axially by no more than half the axial length of the force transmission component, the force transmission component absorbs thrust fluctuations through elastic deformation.

[0010] The stent delivery device provided in this application includes an axially extending push rod, which provides power for stent delivery and propels the stent along the vascular pathway. The distal end of the push rod is provided with a force-buffering component near or located at the distal end of the stent delivery device, including at least one force-transmitting member. This force-transmitting member forms a non-zero angle with the axial centerline of the push rod to ensure that the thrust is transmitted to the force-buffering component as quickly as possible and is effectively decomposed and buffered by the force-buffering component.

[0011] The force transmission component is typically pre-designed so that, without external force constraint, it forms a predetermined non-zero angle with the axial centerline of the push rod and tends to maintain or approach this angle. Inside the conduit, the force transmission component is constrained by the conduit wall, but because it still has a tendency to return to the predetermined angle, and because the conduit has a non-zero inner diameter, the force transmission component will still form a non-zero angle with the axial centerline of the push rod inside the conduit, but this angle is smaller than the predetermined angle.

[0012] For diseases such as hemangiomas and endovascular stenosis, lesions may appear in different locations within the body's vascular system, including the proximal, mid, or distal segment of a vessel. When a lesion is located in the distal segment of a vessel, it is usually accompanied by a bifurcation structure, meaning the lesion is near or located in the bifurcation area. Those skilled in the art should understand that regardless of the lesion's location within the vessel, the final landing point of the stent is always set distal to the lesion. That is, the stent must cross the lesion and be withdrawn distally or pushed forward to achieve precise implantation in the lesion area. This process typically relies on the manipulation of the withdrawing catheter and / or the pushing of the stent to ensure accurate stent coverage of the lesion during deployment, improving treatment efficacy and avoiding complications caused by misalignment.

[0013] During stent delivery, the stent and stent delivery device are located inside the catheter. Clinical procedures typically involve withdrawing the catheter and pushing the stent delivery device to release the stent at the target location. Unavoidable fluctuations in pushing force during these maneuvers can cause sudden forward movement of the guidewire or delivery structure distal to the stent delivery device, resulting in mechanical stimulation of the vessel wall. Even with minimal fluctuations in pushing force, the tortuous nature of the vascular pathway means that the transmission of force during pushing or withdrawing is affected by the vessel's curvature and friction, preventing the force from being transmitted 100% evenly to the distal end and impacting distal maneuverability.

[0014] In short, in practice, distal structures are prone to uneven thrust, causing them to come into contact with the blood vessel wall and even apply excessive local pressure, increasing the risk of blood vessel damage.

[0015] For lesions in bifurcated vessels, the risk of vessel puncture is greater. This is mainly because when a hemangioma is located at a vessel bifurcation, the distal end of the stent lands at the bifurcation, and its opening is perpendicular to the vessel wall on the opposite side of the bifurcation (referred to as the downstream vessel wall). After the distal end of the stent is deployed, the space that the distal end of the delivery system can extend is extremely limited. When this space cannot accommodate the withdrawal catheter and / or the sudden forward movement of the guidewire or delivery structure during the stent delivery device push-up process, the distal end of the stent delivery device will exert a large-angle puncture force on the downstream vessel wall, increasing the risk of vessel puncture. Normally, the landing point of the distal end of the stent is located in the downstream region of the hemangioma. The diameter of the vessel in this region is usually smaller than the diameter of the vessel at the location of the hemangioma, approximately the nominal diameter of the stent to be implanted. In other words, the length of space that the distal end of the delivery system can extend is approximately within the range of the nominal diameter of the stent to be implanted. This application configures the stent delivery device such that when the axial thrust applied to the proximal end of the push rod causes the proximal end of the stent delivery device to move axially by no more than half the axial length of the force transmission member, the force transmission member can absorb thrust fluctuations through elastic deformation to ensure the stability of the distal thrust. The force buffering component can effectively reduce the force changes at the distal end, avoid sudden forward movement of the distal guidewire or delivery structure, and reduce mechanical stimulation to the blood vessel wall. Simultaneously, the distance between the distal end of the force buffer component and the distal end of the stent delivery device as a whole is limited to less than or equal to the nominal diameter of the stent delivered by the stent delivery device. This shortens the structural length of the stent delivery device located on the distal end of the force buffer component, forming a compact "headless" stent delivery device. Thus, even before the force buffer component is released, the protruding length of the distal end of the stent delivery device is minimized. By controlling this length within the nominal diameter of the stent to be delivered, the operability and safety of the delivery system in confined spaces such as distal blood vessels and bifurcation areas can be effectively improved, reducing the risk of accidental contact with the blood vessel wall and enhancing navigation ability and adaptability in narrow or highly tortuous blood vessels. It is particularly suitable for demanding clinical application scenarios such as bifurcation hemangiomas.

[0016] Specifically, this application incorporates a force buffer component to buffer the force exerted on the blood vessel wall by the distal end of the stent delivery device. This ensures that during the pulling and / or pushing process, the distal thrust remains within a controllable low range, effectively reducing mechanical stimulation to the blood vessel wall, lowering the risk of vascular injury caused by fluctuations in distal thrust, and improving the safety of the stent implantation process.

[0017] The force buffer component of this application can be understood as a structure capable of converting and absorbing the pushing force into deformation energy. Typical, but not limited, forms include springs, deformable spheres, deformable cages, etc. These structures can absorb excess pushing force through elastic deformation during the pushing process, ensuring a smoother transmission of pushing force at the distal end, thereby optimizing the stent release process, improving implantation accuracy, and reducing surgical complications caused by pushing force fluctuations.

[0018] This application does not specify the specific structure of the force buffer component; any structure with mechanical buffering capability known in the art can be used in this application.

[0019] Preferably, the structure of the force buffer component includes any one of a lantern-shaped mesh structure, a spiral structure, or a wave-shaped structure.

[0020] Preferably, in the unrestrained state, the angle between the distal end of the force transmission member and the axial centerline is 5 to 70°, such as 8°, 13°, 18°, 25°, 28°, 32°, 37°, 42°, 48°, 54°, 60°, 64°, 69°, etc.

[0021] In an unconstrained state, the angle between the force transmission component and the axial centerline is set to 5–70° to ensure that the force transmission component can effectively decompose and buffer the axial thrust during the pushing process. When a thrust is applied to the proximal end of the pushing rod, the thrust is transmitted axially to the force transmission component. Since the force transmission component forms a non-zero angle with the axial centerline, part of the thrust is decomposed along the direction of the component, causing it to undergo elastic deformation, thereby absorbing some thrust fluctuations. If the angle is too small (e.g., less than 5°), the axial force on the force transmission component is too strong, and the deformation requires a large starting force, which may still generate large thrust fluctuations at the distal end, thus increasing the risk of distal end protrusion. If the angle is too large (e.g., more than 70°), the elastic deformation space of the force buffer component becomes smaller, the range of distal thrust fluctuations increases, and the force transmission component becomes too soft, resulting in a decrease in the axial rigidity of the force buffer component, which in turn affects the pushing efficiency. Therefore, the angle range of 5–70° achieves an optimal balance between buffering thrust and maintaining pushing rigidity, effectively absorbing thrust fluctuations without reducing the pushing performance of the conveying device.

[0022] However, it should be noted that although the preferred angle between the force transmission component and the axial centerline is 5–70°, this does not mean that angles less than 5° or greater than 70° cannot be used in this application. In appropriate application scenarios, angles exceeding the 5–70° range can still be considered as alternative technical solutions. For example, structures with an angle less than 5° are generally more suitable for situations with strong vessel wall toughness or a large distal pushing space, while structures with an angle greater than 70° are suitable for situations with weak vessel wall toughness or a small distal pushing space.

[0023] In one specific embodiment, the force transmission component is made of a filamentous material with an elastic modulus of 30 to 180 GPa (e.g., 35 GPa, 40 GPa, 46 GPa, 58 GPa, 70 GPa, 90 GPa, 105 GPa, 120 GPa, 130 GPa, 140 GPa, 150 GPa, 165 GPa, 170 GPa, 178 GPa, etc.), preferably any one or a combination of at least two of the following: hyperelastic material and shape memory material.

[0024] Preferably, when the axial thrust applied to the proximal end of the push rod causes the distance by which the proximal end of the support conveying device moves axially to no more than half the axial length of the force transmission member, the axial thrust fluctuation at the distal end of the support conveying device is kept within ≤50mN, such as 45mN, 40mN, 36mN, 32mN, 26mN, 20mN, 18mN, 12mN, 8mN, 5mN, 2mN, etc.

[0025] The axial thrust fluctuation at the distal end of the stent delivery device is kept within ≤50mN, which can greatly reduce damage to the blood vessel wall, improve the delivery safety of the stent delivery device, and broaden the application scenarios of the stent delivery device, making it suitable for the treatment of bifurcation vascular lesions.

[0026] This application does not specifically limit the method for measuring axial thrust fluctuation. Typical but non-limiting methods include:

[0027] Simulating the actual vascular environment, the stent delivery device is pushed so that the distal end abuts against the distal force test position, and then pushed a predetermined distance at the proximal end. The force value at the distal end of the stent delivery device is measured and recorded to obtain the fluctuation range of the distal force value.

[0028] For example, a full-module push-back force tester can be used to simulate the actual vascular environment, and the force value at the distal end of the stent delivery device can be measured by a distal force sensor, wherein the distal force test position is the probe of the distal force sensor.

[0029] As one of the optional embodiments, the force buffer component is made of a material including a Nitinol alloy.

[0030] This application preferably uses filamentous materials with an elastic modulus of 30–180 GPa as the material for the force transmission component. The elastic modulus reflects the material's resistance to deformation; materials within this range can provide sufficient deformation capacity while ensuring good elastic recovery.

[0031] In terms of specific material selection, superelastic materials or shape memory materials, or a combination of both, are preferred. For example, Nitinol alloy is a typical superelastic and shape memory alloy, exhibiting strong elastic deformation capacity within a small deformation range, enabling it to quickly absorb and release thrust fluctuations. Furthermore, Nitinol alloy can recover its original shape within a certain temperature range, allowing the force-buffering component to maintain a stable shape and function after stent deployment. The material properties of Nitinol alloy enable stent delivery devices to adapt to complex vascular environments and maintain good mechanical properties during clinical use.

[0032] In one specific implementation, the force buffer component is a lantern-shaped mesh structure. The lantern-shaped mesh structure is obtained by weaving multiple elastic threads into a hollow tube network structure and then pre-forming it into a structure where the two ends converge and the middle cavity is hollow. The elastic threads are force transmission components. Alternatively, the lantern-shaped mesh structure is obtained by extending at least two elastic threads side by side and pre-forming them into a structure where the two ends converge and the middle cavity is hollow. The elastic threads are force transmission components.

[0033] The lantern-shaped mesh structure is composed of multiple strands of elastic threads forming force-transmitting components, and is shaped by a pre-forming process to converge at both ends and form a cavity in the middle. Preferably, the force-transmitting components are distributed along the warp direction on the surface of the lantern-shaped structure, or extend at an angle to the warp direction.

[0034] The force-transmitting components are distributed along the meridian direction, meaning they extend from one end of the space frame along the meridian direction to the other, forming a regular axial support structure. This arrangement provides high axial rigidity and allows for elastic deformation along the meridian direction under stress, thus buffering thrust fluctuations.

[0035] The force transmission components are distributed at an angle to the meridian direction, providing more flexible deformation characteristics. During the pushing process, this angle design allows the thrust to be more easily decomposed into forces in multiple directions, enabling the lantern-shaped grid structure to more effectively distribute the load and thus improve the efficiency of thrust buffering.

[0036] In one specific embodiment, the cross-braided perforated network structure is formed by cross-weaving multiple strands of elastic yarn, creating multiple regular perforated mesh openings during the weaving process. The force-transmitting components extend and distribute at an angle to the warp direction. These mesh structures provide sufficient space for elastic deformation, allowing the force-buffering components to evenly distribute the load and generate controlled deformation when subjected to thrust, thereby effectively absorbing and buffering thrust fluctuations. This design ensures that even if the proximal thrust changes during stent delivery, the distal force remains within a relatively stable range, reducing the impact of distal protrusion on the vessel wall.

[0037] In another specific embodiment, the mesh structure formed by side-by-side arrangement of elastic threads consists of at least two elastic threads arranged side-by-side, forming a hollow structure with converging ends through a pre-shaped process. Force transmission components can extend along the warp direction on the surface of the lantern-shaped structure, or they can extend at a certain angle to the warp on the surface of the lantern-shaped structure. In this method, the arrangement of force transmission components is more regular, providing more stable force buffering characteristics. During the pushing process, the axial thrust is transmitted along the direction of the elastic threads. However, because the threads are distributed at a certain angle to the axial direction, part of the thrust is converted into a lateral component, causing controlled deformation of the force buffer components, thereby absorbing thrust fluctuations and preventing sudden increases in force at the distal end.

[0038] Preferably, the force buffer component has a guide portion at its distal end, and the guide portion is preferably designed integrally with the converging end of the force transmission component.

[0039] To further optimize the stability of the distal end of the lantern-shaped space frame structure, this application preferably provides a guide portion at the distal end of the force buffer component. The guide portion serves to guide the support during transport, enhancing the stability of the distal end of the transport device and reducing the probability of lateral offset or uncontrolled displacement of the distal structure during support release. The guide portion described in this application can be connected to the distal end of the converging end of the force transmission component via a connection method (such as bonding or welding), or the converging end can be directly extended as the guide portion. Preferably, the guide portion is designed integrally with the converging end of the force transmission component, making the structure more compact, reducing additional component connections, and improving overall mechanical performance.

[0040] This application optimizes the construction method of the lantern-shaped mesh structure, the arrangement of force transmission components, and the design of the guide section to ensure that the stent delivery device can effectively buffer thrust fluctuations during stent release, improve distal stability, reduce the risk of vascular injury, and optimize the accuracy of stent implantation during delivery and release.

[0041] As another specific implementation, the lantern-shaped grid structure is obtained by carving a metal tube into a hollow grid structure and then pre-forming it into a structure in which the two ends converge and the middle cavity is hollow, so that the support columns of the hollow grid are connected end to end to form a force transmission component.

[0042] By carving a hollowed-out space frame structure into metal tubes, the structural integrity of the space frame can be maintained, ensuring good mechanical properties and making force transmission more stable. In the hollowed-out space frame, the supports are connected end to end to form force transmission components. When a thrust is applied to the near end of the push rod, the thrust is transmitted along these supports. Due to the special design of the support structure, it can undergo elastic deformation during the stress process, thereby absorbing thrust fluctuations and reducing the instability of the thrust at the far end.

[0043] Preferably, the force buffer component has a guide portion at its distal end, and the guide portion is preferably integrated with the converging end of the force transmission component. To further enhance the distal stability of the conveying device, this application preferably provides a guide portion at the distal end of the force buffer component. The function of the guide portion is to stabilize the front end trajectory of the conveying device and prevent deviation or uncontrolled displacement during the conveying process.

[0044] The guide section and the force transmission component are preferably designed as an integrated unit. That is, the guide section can be formed by extending the force transmission component or directly processed as an integrated structure, which improves the overall mechanical stability of the support conveying device and makes the conveying device more controllable during pushing and releasing.

[0045] Preferably, the hollowed-out mesh frame is prepared by laser engraving and / or chemical etching.

[0046] Laser engraving technology is applicable to a variety of high-performance metal materials, such as nickel-titanium alloys and cobalt-chromium alloys, and can ensure that force-absorbing components have excellent elastic deformation capabilities and long-term durability.

[0047] This application uses a lantern-shaped mesh structure formed by carving metal tubes, which can provide more stable and precise thrust control during stent delivery and release, reduce the risk of distal protrusion, and improve the safety and controllability of stent implantation.

[0048] In another specific embodiment, the force buffer component is an elastic structure pre-shaped into a spiral structure and / or a wave structure, and a guide portion is provided at the distal end of the force buffer component, the guide portion extending axially.

[0049] Preferably, the spiral structure and / or wavy structure are obtained through a predetermined process.

[0050] Both helical and / or wavy structures can undergo elastic deformation under axial force, thereby absorbing part of the thrust during the pushing process and reducing the fluctuation range of the far-end thrust.

[0051] The spiral structure consists of spiral components made of elastic material, which can be compressed or stretched axially during the pushing process, allowing the thrust to be decomposed and buffered within the spiral structure. The spiral shape design enables the force buffer component to gradually release the accumulated energy after being subjected to force, thereby avoiding the sudden transmission of thrust and improving the remote stability of the support conveying device.

[0052] The wave-like structure consists of multiple elastic components arranged in a wave pattern. During delivery, it undergoes controlled lateral deformation, distributing the thrust along the wave structure and absorbing thrust fluctuations through deformation. The wave-like structure provides a gentler force buffering effect, making it particularly suitable for stent delivery in tortuous blood vessels or areas of stenosis.

[0053] Compared to rigid linear force buffer structures, spiral or wave-shaped structures have superior flexible buffering characteristics, so that the proximal thrust is not directly and abruptly transmitted to the distal end, but is gradually released through the deformation of the buffer structure, thereby reducing the force fluctuation at the distal end and preventing the distal end of the delivery device from protruding or causing mechanical damage to the blood vessel wall.

[0054] To improve the trajectory stability of the support conveying device during the pushing and releasing process, especially the stability at the far end, this application provides an axially extending guide portion at the far end of the force buffer component, making it easier for the far end of the conveying device to maintain a stable pushing direction and reducing the probability of deviation or rotation.

[0055] Both the spiral and wave-shaped structures are obtained through a pre-designed process to ensure good deformation recovery during the pushing process and to maintain stable mechanical properties.

[0056] Preferably, the length of the guide portion is less than or equal to the nominal diameter of the support conveyed by the support conveying device. More preferably, the length of the guide portion is 0 to 0.8 times the nominal diameter of the support conveyed by the support conveying device, where 0 indicates that no guide portion is provided.

[0057] Preferably, the guide portion is sleeved on the distal end of the force buffer component, that is, the force transmission component of the force buffer component forms an extension portion at the converging end, and the guide portion is fixed to the outside of the extension portion.

[0058] This design improves the mechanical coordination between the guide section and the force buffer component. The guide section, fitted onto the distal end of the force buffer component, provides additional structural support, reducing the probability of unexpected lateral displacement or torsion of the distal structure during transport and release, thus improving the predictability and accuracy of the transport process. The presence of the guide section helps to evenly distribute the pushing force at the distal end, enabling the force buffer component to more stably absorb thrust fluctuations, further reducing thrust fluctuations at the distal end.

[0059] Preferably, the guide portion includes a rigid ring and / or a flexible ring; in specific implementations, the guide portion can adopt a rigid or flexible structure, the specific choice depending on the requirements of the target application scenario. Generally, in high-precision stent delivery requirements, a more rigid guide portion can be used to provide a more stable delivery trajectory; in tortuous vascular environments, a more compliant guide structure can be used to adapt to complex vascular morphology and reduce stress on the vascular wall.

[0060] Preferably, the rigid ring is a radiopaque ring; the rigid ring is typically made of radiopaque material, and its main function is to provide more stable distal support and enhance visibility under intraoperative image guidance. The rigid ring ensures that the guide portion is not easily deformed during delivery, thereby improving the distal rigidity of the delivery device and making stent release more controllable.

[0061] This application does not specifically limit the radiopaque material used; any radiopaque material available to those skilled in the art can be used to prepare the radiopaque ring, typically but not limited to platinum, platinum alloys, etc. These materials can be clearly visualized under X-rays or other medical imaging equipment, helping doctors to monitor the position of the delivery device and the release of the stent in real time during surgery, thus improving surgical precision.

[0062] Preferably, the flexible ring is a flexible single ring with a spiral winding structure, and more preferably a spiral coil.

[0063] The flexible ring is designed to provide better compliance and flexibility to accommodate the delivery needs of tortuous or vulnerable vessels. The flexible single ring can be made of highly elastic materials, providing some deformation capacity during delivery to reduce pressure on the vessel wall. Alternatively, a helical coil can be used as the primary form of the flexible ring. This structure offers excellent axial compliance and radial support, making it easier for the delivery device to pass through tortuous vessels while providing adequate support during stent deployment to prevent excessive distal protrusion.

[0064] Preferably, the guide portion is made of a radiopaque material. During interventional surgery, the radiopaque material allows the surgeon to observe the specific position of the guide portion in real time using imaging equipment such as X-rays, CT, or MRI, ensuring that the delivery device and stent are in the ideal implantation position, thereby improving the accuracy of implantation and the safety of the surgery.

[0065] In the preferred embodiment of this application, the structural design of the guide section is optimized to enable it to play an important role in stent delivery, intraoperative positioning, stent release, and vascular protection, thereby improving the overall performance of the stent delivery device and ensuring the efficiency and safety of interventional surgery.

[0066] In an optional embodiment, the distal end of the guide portion is provided with a buffer end, the buffer end having a Shore hardness D of 50 to 80, such as 55, 58, 63, 68, 75, etc., and a tensile property of 2% to 150%, such as 3%, 16%, 33%, 55%, 73%, 95%, 113%, 135%, 148%, etc.

[0067] With a Shore hardness in the range of 50 to 80, the buffer end can maintain its shape when the guide is under load, while also having sufficient flexibility to deform when subjected to impact, absorb energy, and reduce damage to surrounding structures or biological tissues.

[0068] Tensile properties indicate a material's ability to stretch under tensile force. A range of 2% to 150% allows the material to meet deformation requirements, withstanding both minor deformations and significant tensile stresses without fracturing. This enables the buffer end to navigate more easily through tortuous blood vessels during transport, improving its adaptability under dynamic loads and overall durability.

[0069] Preferably, the material of the buffer end is a biocompatible polymer adhesive or solder paste, and more preferably includes UV-curable adhesive or epoxy resin adhesive.

[0070] The second objective of this application is to provide a support system, comprising:

[0071] Self-expanding stent;

[0072] catheter;

[0073] One of the objectives is to provide a stent delivery device disposed within the conduit and extending axially, wherein the stent delivery device loads the stent at its distal end and is used to receive a pushing force and transmit the pushing force to the distal end; the distal end of the stent is defined as point X.

[0074] On the stent delivery device, a force change point A is provided at a predetermined axial distance (≥1.5mm) from the proximal side of point X; a force buffer component is provided on the distal side of the force change point A, so that after the force change point A of the stent delivery device extends beyond the distal end of the catheter, the pushing force fluctuation range transmitted to the distal end is ≤50mN within the range of the proximal end advance displacement of the stent delivery device not exceeding 1.5mm.

[0075] During stent delivery, once the stent reaches the vicinity of the lesion, stent release is typically controlled by withdrawing the catheter and advancing the stent delivery device. However, during this process, the pulling and / or pushing forces applied to the stent delivery device proximally are transmitted to the distal end. Due to the tortuous nature of the blood vessel, these forces are lost during transmission, resulting in a weakened distal response and reduced controllability. Furthermore, the tortuous vascular structure may cause the distal end of the stent delivery device to come into contact with the vessel wall or even apply additional pressure, thereby increasing the risk of vascular injury. This application addresses this issue by incorporating a force-buffering component at the distal end of the stent delivery device to buffer the forces applied to the vessel wall, controlling their fluctuation to ≤50mN. This ensures that the force on the distal end remains within a controllable range during advancement or withdrawal, reducing irritation and damage to the vessel wall and improving the safety of stent implantation.

[0076] When the stent delivery device is advanced a specific distance Y proximally, factors such as vascular tortuosity often cause a loss in the advancement stroke, resulting in the actual distal advancement distance being less than Y. To ensure the effectiveness of the force buffer component, this application limits the predetermined distance to ≥1.5mm to ensure that the force buffer component can be fully released and function. When point A of the stent delivery device extends beyond the distal end of the catheter, as long as the distal advancement displacement is within the range of 0 to 1.5mm, the force fluctuation on the vessel wall can be ensured to be ≤50mN. Furthermore, considering the existence of advancement stroke loss, the actual proximal advancement distance can usually exceed 1.5mm without affecting the function of the force buffer component.

[0077] In the stent system, the force buffer component of the stent delivery device is positioned near the distal end. After the stent is delivered to the distal end of the lesion, the operator begins pushing and / or withdrawing the stent, gradually releasing the stent and the distal end of the stent delivery device. When the force change point A extends beyond the distal end of the catheter, the force buffer component is fully released. At this point, as long as the proximal advancement displacement does not exceed 1.5 mm, the fluctuation range of the pushing force transmitted to the distal end can be ensured to be ≤50 mN. Simultaneously, since the force buffering range of the force buffer component does not exceed half the axial length of the force transmission component, the distal end of the stent is typically flush with the distal end of the force buffer component, or located between the proximal and distal ends of the force buffer component. This assists in better stent deployment during the initial stage of stent release. More importantly, the predetermined distance of ≥1.5 mm ensures that after the force change point A extends beyond the distal end of the catheter, there is sufficient axial space for the force buffer component, giving the force transmission component sufficient length to buffer and distribute the force on the distal end of the stent delivery device.

[0078] It should be noted that during stent delivery, the stent delivery device is typically under axial tension and radial compression. Only when the stent delivery device extends partially or completely beyond the catheter will the release portion undergo axial contraction and radial expansion to adapt to the intravascular environment and complete stent implantation.

[0079] Preferably, the axial length of the force transmission component is ≥3.0mm.

[0080] The axial length of the force transmission component is ≥3.0mm. After the force change point A extends beyond the conduit, the distance between X and A will be greater than or equal to 3.0mm. This can effectively ensure that after the force change point A of the stent delivery device extends beyond the far end of the conduit, the advance displacement of the stent delivery device at the proximal end is within the range of no more than 1.5mm and does not exceed half the axial length of the force transmission component.

[0081] Preferably, the self-expanding bracket is fitted onto the bracket conveying device in the conveying state, and the distal end of the self-expanding bracket is located outside the force buffer component.

[0082] The distal end of the self-expanding stent is located outside the force buffer component, which allows a radial expansion force to be generated on the self-expanding stent at the moment the force buffer component is released, thus assisting the stent in opening.

[0083] Preferably, the distal end X of the stent to be delivered is located between the force change point A and the distal end of the force buffer component. Positioning the distal end of the stent to be delivered in a suitable location can, on the one hand, reduce the risk of the stent delivery device extending too far beyond the stent's distal end during stent release, thus preventing damage to the blood vessel wall and increasing the operational space of the distal end of the stent delivery device; on the other hand, it can improve the controllability of stent delivery, especially the controllability of the distal end.

[0084] Compared with the prior art, this application has the following beneficial effects:

[0085] This application incorporates a force buffer component in the stent delivery device to effectively regulate the pushing force transmitted to the vessel wall at its distal end. This ensures that during the pulling and / or pushing process, the force applied to the vessel wall by the stent delivery device remains within a controllable low force range, thereby significantly reducing mechanical stimulation and potential damage risks to the vessel wall and further improving the safety of stent implantation. Attached Figure Description

[0086] Figure 1 A schematic diagram of the support conveying device provided in Example 1;

[0087] Figure 2 This is a schematic diagram of the stent delivery device in the stent system provided in Example 1, before it extends out of the conduit;

[0088] Figure 3 This is a schematic diagram of the stent delivery device extending from the conduit in the stent system provided in Example 1;

[0089] Figure 4 The measurement results of the pushing force fluctuation range at the distal end of the support delivery device provided in Example 1;

[0090] Figure 5 This is a schematic diagram of the support conveying device provided in Example 2;

[0091] Figure 6 The measurement results of the pushing force fluctuation range at the distal end of the support delivery device provided in Example 2;

[0092] Figure 7 This is a schematic diagram of the support conveying device provided in Example 3;

[0093] Figure 8 The measurement results of the pushing force fluctuation range at the distal end of the support delivery device provided in Example 3. Detailed Implementation

[0094] The technical solution of the present invention will be further explained and described below with reference to specific embodiments. However, it should be noted that the specific embodiments are only a specific implementation and explanation of the essence of the technical solution of the present invention, and should not be construed as a limitation on the scope of protection of the present invention.

[0095] In the description of this invention, it should be understood that the terms "distal" and "proximal" should be understood as viewed from the direction of the surgical operator; "distal" is the end away from the surgical operator, while "proximal" is the end closer to the surgical operator. The term "axial" refers to the direction of stent delivery, and "axial centerline" is a hypothetical central axis extending axially; no actual central axis exists in the technical solution.

[0096] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0097] Test example:

[0098] The pushing force transmission characteristics of the support conveying device provided in the following embodiments were tested using a full-module pushing and pulling force tester (model RXDZ-TLN02G 10MMW). The specific steps are as follows:

[0099] (1) Assembly test system: Assemble the stent delivery device to be tested into the distal end of the microcatheter; fix the microcatheter in the test path of the full module push-back force tester to ensure that its path simulates the bending characteristics of the actual vascular environment; arrange the distal force sensor at the distal end of the test path; push the stent delivery device to be tested so that the force buffer component just extends out of the microcatheter and its distal end abuts against the probe of the distal force sensor to detect the change in the push force transmitted to the distal end.

[0100] (2) Test execution: The proximal pushing mechanism of the full-module push-back force tester applies an axial thrust to the support conveying device, and records the force value detected by the remote force sensor when the far end of the support conveying device reaches the remote force sensor. The push displacement is within half the axial length of the force transmission component (1.5 mm in Examples 1 to 3, and 2.5 mm in Example 4).

[0101] Example 1

[0102] like Figure 1 ( Figure 1 As shown in the structural schematic diagram of the support conveying device provided in Embodiment 1, Embodiment 1 provides a support conveying device 100, comprising:

[0103] Axially extending push rod 110;

[0104] A force buffer component is disposed at the distal end of the push rod 110; the force buffer component is a lantern-shaped mesh structure 120, which in its natural state has a structure in which the two ends converge and the middle cavity is hollow. The lantern-shaped mesh structure 120 is formed by laser engraving a hollow pattern on a metal tube, and then pre-shaping it by heating to obtain a structure in which the two ends converge and the middle expands. The frame pillars of the hollow pattern are connected end to end to form a force transmission component 1212; the proximal end of the lantern-shaped mesh structure 120 is fixedly connected to the distal end of the push rod 110, and a spiral coil 122 is wound around the distal end of the lantern-shaped mesh structure 120. The distal end of the spiral coil 122 is cured with UV-curable adhesive (model S2000-XLA) as a buffer end 123. The spiral coil 122 and the buffer end 123 together serve as a guide.

[0105] The hollowed-out pattern includes four meridional columns 121a and connecting beams 121b connecting adjacent meridional columns 121a. The connecting beams 121b are S-shaped, and both ends of the connecting beams 121b are connected to the adjacent meridional columns 121a. The meridional columns 121a are force transmission components 1212.

[0106] In the lantern-shaped grid structure 120 formed after pre-molding, the angle between the force transmission member 1212 and the axial centerline is 40°. The metal tube is a nickel-titanium alloy metal tube with an elastic modulus of 30-75 GPa.

[0107] Application Example 1

[0108] like Figures 2-3 ( Figure 2 This is a schematic diagram of the stent delivery device in the stent system provided in Example 1, before it extends out of the catheter. Figure 3 As shown in the schematic diagram of the stent delivery device extending from the conduit in the stent system provided in Example 1, Application Example 1 provides a stent system including:

[0109] The stent 200 (nominal diameter 3.2 mm), the catheter 300, and the stent delivery device 100 provided in Embodiment 1 extend inside the catheter 300, and the self-expanding stent 200 is mounted on the distal end of the stent delivery device 100; the proximal end of the force buffer component of the stent delivery device 100 is point A, and the length of the force buffer component in the expanded state is 3.0 mm; the distal end of the self-expanding stent 200 is point X, and the distal end (point X) of the self-expanding stent 200 is located near the location of the buffer end 123.

[0110] During operation, the operator pushes the push rod 110 of the stent delivery device 100 or retracts the conduit 300, causing the distal end of the stent delivery device 100, which carries the self-expanding stent 200, to extend beyond the conduit 300. When point A of the stent delivery device 100 extends beyond the distal end of the conduit, the force buffer component is fully released and enters a natural state (both ends are constricted and the middle cavity is empty). At this time, when the proximal end of the push rod 110 pushes a distance within 1.5 mm, the pushing force fluctuation range of the distal end of the stent delivery device 100 is 0 to 20 mN, which can be controlled within 50 mN.

[0111] According to the test method of the test example, the measurement results of the pushing force fluctuation range at the distal end of the stent delivery device provided in Example 1 are as follows: Figure 4 As shown, the Proximal line represents the proximal force value, and the Distal line represents the distal force value.

[0112] Example 2

[0113] like Figure 5 ( Figure 5 As shown in the structural schematic diagram of the support conveying device provided in Embodiment 2, Embodiment 2 provides a support conveying device 100, which differs from Embodiment 1 only in the structural arrangement of the force buffer component, specifically:

[0114] Force buffer components are installed on push rod 110 ( Figure 5 (The full length of the push rod 110 is not shown) At the far end, the lantern-shaped mesh structure 120 has a structure in its natural state where the two ends converge and the middle cavity is hollow. The lantern-shaped mesh structure 120 is formed by cross-weaving eight elastic threads 121c into a hollow tube structure. After the two ends are gathered and brought close together to expand the middle cavity, it is pre-shaped by heating. The unbound part of the elastic threads 121c is the force transmission component 1211. After the two ends of the tube structure are gathered, the near end is fixed to the far end of the push rod 100. The far end is wound with a spiral coil 122, and the far end of the spiral coil 122 is cured with UV-curable adhesive (model S2000-XLA) as a buffer end 123. The spiral coil 122 and the buffer end 123 together serve as a guide.

[0115] In the lantern-shaped mesh structure 120 formed after pre-molding, the force transmission member 1211 has an angle of 20° with the axial center line, and the force transmission member 1211 extends and is distributed at a certain angle (60°) with the warp direction of the lantern-shaped mesh structure. The elastic wire 121c is a nickel-titanium metal wire with an elastic modulus of 30-75 GPa.

[0116] The buffer end 123 has a Shore hardness D of 50 to 75 and a tensile strength of 50% to 150%; the spiral coil 122 is made of radiopaque material and has an axial length of 3 mm.

[0117] In other optional embodiments, the elastic filament 121c may also be selected from filamentous materials with an elastic modulus of 30 to 180 GPa, such as superelastic materials, shape memory materials, etc., typically but not limited to metal filaments such as nickel-titanium alloys and cobalt-chromium alloys, polymer filaments with shape memory, or metal filaments or polymer filaments coated with functional coatings.

[0118] Application Example 2

[0119] The only difference from Application Example 1 is that the support conveying device 100 provided in Example 1 is replaced with the support conveying device provided in Example 2.

[0120] The test method is the same as in the test example, except that the stent delivery device provided in Example 1 is replaced with the stent delivery device provided in Example 2. When the proximal end of the push rod 110 is pushed a distance of 1.5 mm, the pushing force fluctuation range of the distal end of the stent delivery device 100 is 0-10 mN, which can be controlled within 50 mN. According to the test method of the test example, the measurement results of the pushing force fluctuation range of the distal end of the stent delivery device provided in Example 2 are as follows: Figure 6 As shown, the Proximal line represents the proximal force value, and the Distal line represents the distal force value.

[0121] Example 3

[0122] like Figure 7 ( Figure 7 As shown in the structural schematic diagram of the support conveying device provided in Embodiment 3, Embodiment 3 provides a support conveying device 100, which differs from Embodiment 1 only in the structural arrangement of the force buffer component, specifically:

[0123] A force buffer component is located at the distal end of the push rod 110. The force buffer component is a lantern-shaped mesh structure 120. In its natural state, the lantern-shaped mesh structure 120 has a structure in which the two ends converge and the middle cavity is hollow. The lantern-shaped mesh structure 120 is formed by arranging 6 elastic wires 121c side by side into a tubular structure. After the two ends are gathered together and brought close together to expand the middle cavity, it is pre-shaped by heating. The unbound part of the elastic wires 121c is the force transmission component 1211. After the two ends of the tubular structure are gathered together, the proximal end is fixed to the distal end of the push rod 100. The distal end is wound with a spiral coil 122, and the distal end of the spiral coil 122 is cured with UV-curable adhesive (model S2000-XLA) to serve as a buffer end 123. The spiral coil 122 and the buffer end 123 together serve as a guide.

[0124] In the pre-formed lantern-shaped mesh structure 120, the force transmission member 1211 forms an angle of 30° with the axial centerline, and the force transmission member 1211 is distributed along the warp direction on the surface of the lantern-shaped mesh structure. The elastic wire 121c is a nickel-titanium metal wire with an elastic modulus of 30-75 GPa.

[0125] Application Example 3

[0126] The only difference from Application Example 1 is that the support conveying device 100 provided in Example 1 is replaced with the support conveying device provided in Example 2.

[0127] The test method is the same as in Test Example 1, except that the stent delivery device provided in Example 1 is replaced with the stent delivery device provided in Example 3. When the proximal end of the push rod 110 is pushed a distance of 1.5 mm, the pushing force fluctuation range of the distal end of the stent delivery device 100 is 0–33 mN, which can be controlled within 50 mN. According to the test method of the test example, the measurement results of the pushing force fluctuation range of the distal end of the stent delivery device provided in Example 3 are as follows: Figure 8 As shown, the Proximal line represents the proximal force value, and the Distal line represents the distal force value.

[0128] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A support conveying device, characterized in that, include: Axially extending push rod; A force buffer component is disposed at the distal end of the push rod; the force buffer component includes at least one force transmission member, and in an unrestrained state, the distal end of the force transmission member extends at a non-zero angle with the axial centerline of the push rod. In an unrestrained state, the distance between the distal end of the force buffer component and the distal end of the entire support conveying device is less than or equal to the nominal diameter of the support conveyed by the support conveying device. The force buffer component is configured such that when the axial thrust applied to the proximal end of the push rod causes the proximal end of the support conveying device to move axially by no more than half the axial length of the force transmission component, the force transmission component absorbs thrust fluctuations through elastic deformation.

2. The support conveying device as described in claim 1, characterized in that, The structure of the force buffer component includes any one of the following: lantern-shaped mesh structure, spiral structure, and wave-shaped structure.

3. The support conveying device as described in claim 1, characterized in that, In an unrestrained state, the angle between the distal end of the force transmission member and the axial centerline is 5~70°.

4. The support conveying device as described in claim 1, characterized in that, The force transmission component is made of filamentous material with an elastic modulus of 30~180 GPa.

5. The support conveying device as described in claim 4, characterized in that, The material of the force transmission component includes any one or a combination of at least two of the following: hyperelastic materials and shape memory materials.

6. The support conveying device as described in claim 1, characterized in that, When the axial thrust applied to the proximal end of the push rod causes the proximal end of the support conveying device to move axially by no more than half the axial length of the force transmission member, the axial thrust fluctuation at the distal end of the support conveying device remains within ≤50mN.

7. The support conveying device as described in claim 2, characterized in that, The lantern-shaped mesh structure is obtained by weaving multiple elastic threads into a hollowed-out tube network structure and then pre-forming it into a structure where the two ends converge and the middle cavity is hollow, wherein the elastic threads are force transmission components; or, the lantern-shaped mesh structure is obtained by extending at least two elastic threads side by side and pre-forming them into a structure where the two ends converge and the middle cavity is hollow, wherein the elastic threads are force transmission components.

8. The support conveying device as described in claim 7, characterized in that, The force buffer component is provided with a guide at its distal end.

9. The support conveying device as described in claim 8, characterized in that, The guide section and the converging end of the force transmission component are designed as an integral part.

10. The support conveying device as described in claim 7, characterized in that, The force transmission components are distributed along the meridian direction on the surface of the lantern-shaped structure, or extended at an angle to the meridian direction.

11. The support conveying device as described in claim 2, characterized in that, The lantern-shaped grid structure is obtained by carving metal tubes into a hollow grid structure and then pre-forming it into a structure where the two ends converge and the middle cavity is hollow. The pillars of the hollow grid structure are connected end to end to form a force transmission component.

12. The support conveying device as described in claim 11, characterized in that, The force buffer component is provided with a guide at its distal end.

13. The support conveying device as described in claim 12, characterized in that, The guide section and the converging end of the force transmission component are designed as an integral part.

14. The support conveying device as described in claim 11, characterized in that, The hollowed-out mesh frame is prepared by laser engraving and / or chemical etching.

15. The support conveying device as described in claim 2, characterized in that, The force buffer component is an elastic structure pre-formed into a spiral and / or wave-like structure, and a guide portion is provided at the distal end of the force buffer component, the guide portion extending axially.

16. The support conveying device as described in claim 15, characterized in that, The spiral and / or wavy structures are obtained through a predetermined process.

17. The support conveying device as described in claim 8, 9, 12, 13 or 15, characterized in that, The length of the guide section is less than or equal to the nominal diameter of the support conveyed by the support conveying device.

18. The support conveying device as described in claim 8, 9, 12, 13 or 15, characterized in that, The guide portion is sleeved on the distal end of the force buffer component.

19. The support conveying device as described in claim 8, 9, 12, 13 or 15, characterized in that, The guide portion includes a rigid ring and / or a flexible ring.

20. The support conveying device as described in claim 19, characterized in that, The rigid ring is a non-transparent ring.

21. The support conveying device as described in claim 19, characterized in that, The flexible ring is a flexible single ring with a spiral winding structure.

22. The support conveying device as described in claim 19, characterized in that, The flexible ring is a helical coil.

23. The support conveying device as described in claim 8, 9, 12, 13 or 15, characterized in that, The guide section is made of a non-transparent material.

24. The support conveying device as described in claim 8, 9, 12, 13 or 15, characterized in that, The guide portion is provided with a buffer end at its distal end. The buffer end has a Shore hardness D of 50 to 80 and a tensile strength of 2% to 150%.

25. A support system, characterized in that, include: Self-expanding stent; catheter; The stent delivery device as described in any one of claims 1 to 24 is disposed within the conduit and extends axially, wherein the stent is loaded at its distal end, and the proximal end is used to receive the pushing force and transmit the pushing force to the distal end; the distal end of the stent is defined as point X. On the stent delivery device, a force change point A is provided at a predetermined axial distance from the proximal side of point X; a force buffer component is provided on the distal side of the force change point A, so that after the force change point A of the stent delivery device extends beyond the distal end of the catheter, the pushing force fluctuation range transmitted to the distal end is ≤50mN within the range of the proximal end advancement displacement of the stent delivery device not exceeding 1.5mm. The predetermined distance is ≥1.5mm.

26. The support system as claimed in claim 25, characterized in that, The axial length of the force transmission component is ≥3.0mm.

27. The support system as claimed in claim 25, characterized in that, The self-expanding bracket is fitted onto the bracket conveying device in the conveying state, and the distal end of the self-expanding bracket is located outside the force buffer component.

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