Stent conveying device and stent system comprising same

Abstract

The invention relates to a stent conveying device and a stent system comprising the same. The support conveying device comprises a pushing rod. The force buffering component is arranged at the far end of the pushing rod and comprises at least one force conduction component, a non-zero angle is formed between the force conduction component and the axial center line of the pushing rod, and the distance between the far end of the force conduction component and the whole far end of the stent conveying device is smaller than or equal to the nominal diameter of a stent conveyed by the stent conveying device. When the axial pushing force applied to the near end of the pushing rod enables the near end of the stent conveying device to move in the axial direction by a distance not exceeding half of the axial length of the force conduction component. According to the stent conveying device, the pushing force transmitted to the blood vessel wall can be regulated and controlled, so that the force applied to the blood vessel wall in the pulling and / or pushing process is always in a controllable low force value range, the mechanical stimulation and potential injury risk to the blood vessel wall are reduced, and the stent implantation safety is improved.

Description

Technical Field

[0001] The present invention belongs to the field of medical devices, and particularly relates to a stent delivery device and a stent system including the same. Background Art

[0002] Self-expanding stents are widely used in vascular interventional therapy. Relying on their own self-expansion characteristics, they can radially expand and fix in the blood vessel lumen after the delivery system is withdrawn, thereby maintaining blood vessel patency and / or guiding the blood flow direction. Usually, a self-expanding stent enters the body through a delivery system from the proximal end (such as the radial artery or femoral artery) and is transported along the blood vessel to the lesion site. After reaching the target position, the stent is gradually released under the control of the delivery system and stably adheres to the blood vessel wall by relying on its own radial supporting force to achieve the support of the lesion area and / or blood flow reconstruction. The delivery system usually consists of a catheter, a pusher rod, and internal structures (such as a guide wire and a silicone pad). Its function is to ensure that the stent remains in a compressed state during transportation and is smoothly transported to the target position and stably released at the target position. During the specific operation process, the operator needs to push the internal structure and / or withdraw the catheter to promote the gradual release of the stent.

[0003] However, during the process of transporting a self-expanding stent to the lesion area until its release, the existing delivery systems have certain technical defects and clinical risks. When a self-expanding stent radially expands, its axis usually undergoes a certain degree of contraction. This contraction effect may cause the distal end of the guide wire or pusher rod inside the delivery system to move forward relatively, especially when continuously pushing at the proximal end or withdrawing the catheter. This thrust will be transmitted to the distal end, causing the distal structure of the delivery device to suddenly advance. When the distal structure extends beyond the stent itself and contacts the inner wall of the blood vessel, it may cause mechanical stimulation to the blood vessel wall and even lead to blood vessel injury. In a complex tortuous blood vessel environment, this phenomenon is particularly obvious. Due to the bending of the blood vessel structure, the transmission of the pushing force is not linear, and the mechanical instability at the distal end may be caused by the change in the blood vessel morphology, making the distal guide wire or delivery device more likely to extend beyond the distal end of the stent and contact the blood vessel wall.

[0004] When the lesion occurs at the bifurcation of the blood vessel, the normal blood vessel segment that the distal end of the delivery system can anchor is usually short. In this case, the proximal pushing force may cause the distal end of the delivery device to continuously approach the blood vessel wall or even directly abut against the inner wall of the blood vessel, thereby causing a local blood vessel stress response or potential injury. For such complex blood vessel anatomical structures, the rigid characteristics of the existing delivery systems may exacerbate this problem, making it difficult to stably control the distal structure and thus affecting the accuracy of stent release. In addition, the fluctuation of the pushing force of the delivery system at the distal end may also affect the release stability of the stent. The slight fluctuation of the force during the pushing process may be amplified to the distal end, resulting in unstable movement during the stent release process, affecting the stent wall apposition and the final implantation effect.

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

[0006] In view of the deficiencies of the prior art, one object of the present invention is to provide a stent delivery device, comprising:

[0007] A push rod extending axially;

[0008] A force buffer member provided at the distal end of the push rod; the force buffer member includes at least one force conduction member, and the force conduction member forms a non-zero angle with the axial center line of the push rod; the distance between the distal end of the force buffer member and the distal end of the entire stent delivery device is less than or equal to the nominal diameter of the stent delivered by the stent delivery device.

[0009] The force buffer member is configured 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 a distance not exceeding half of the axial length of the force conduction member, the force conduction member absorbs the thrust fluctuation through elastic deformation.

[0010] The stent delivery device provided in this application includes a push rod extending axially, which is used to provide the power for stent delivery and make the stent advance along the blood vessel path. A force buffer member is provided at the distal end of the push rod, which is close to or located at the distal end of the stent delivery device. The force buffer member includes at least one force conduction member, and the force conduction member forms a non-zero angle with the axial center line of the push rod to ensure that the thrust can be transmitted to the force buffer member as soon as possible and effectively decomposed and buffered by the force buffer member.

[0011] The force conduction member is usually pre-shaped so that when there is no external force constraint, it forms a predetermined non-zero angle with the axial center line of the push rod and tends to maintain or approach this angle. Inside the catheter, the force conduction member is constrained by the catheter wall. However, since it still has a tendency to return to the predetermined angle and the catheter has a non-zero inner diameter, the force conduction member will still form a non-zero angle with the axial center line of the push rod inside the catheter, but this angle is smaller than the pre-shaped angle.

[0012] For diseases such as hemangioma and intravascular stenosis, the lesions may appear at different positions in the body's vascular system, including the proximal segment, middle segment, or distal segment of a certain blood vessel. When the lesion is located in the distal segment of a certain blood vessel, it is usually accompanied by a bifurcation structure of the blood vessel, that is, the lesion is close to or located in the vascular bifurcation area. Those skilled in the art should be clear that regardless of the position of the lesion in the blood vessel, the final landing point of the stent is always set on the distal side of the lesion, that is, the stent needs to cross the lesion and be precisely implanted in the lesion area by retracting from the distal end or by pushing. This process usually relies on the operation of retracting the catheter and / or pushing the stent, so as to ensure that the stent accurately covers the lesion during release, improve the treatment effect, and avoid the risk of complications caused by position deviation.

[0013] During the stent delivery process, the stent and the stent delivery device are located inside the catheter. Clinical operations usually need to retract the catheter and push the stent delivery device to release the stent at the target position. Inevitably, there are thrust fluctuations during the operator's pushing operation, which cause the sudden forward movement of the guide wire or the delivery structure at the distal end of the stent delivery device, resulting in mechanical stimulation to the blood vessel wall; even if the operator's thrust fluctuation is very small, due to the tortuosity of the vascular access, when pushing or retracting, the transmission of the thrust will be affected by the blood vessel curvature and friction, making the force unable to be transmitted to the distal end evenly by 100%, which will also affect the controllability of the distal end.

[0014] In short, in actual operation, the distal structure is prone to be affected by uneven thrust, resulting in contact with the blood vessel wall and even excessive local pressure, increasing the risk of blood vessel injury.

[0015] For lesions in bifurcated blood vessels, the risk of puncturing the blood vessel is greater. This is mainly because when the hemangioma is located at the bifurcation of the blood vessel, the distal end of the stent lands at the bifurcation, and its opening is perpendicular to the blood vessel wall on the opposite side of the bifurcation (abbreviated as the downstream blood vessel wall). After the distal end of the stent is released, the space that the distal end of the delivery system can extend is extremely limited. When this space cannot accommodate the sudden forward movement of the guide wire or the delivery structure during the process of retracting the catheter and / or pushing the stent delivery device, the distal end of the stent delivery device will generate a large-angle piercing force on the downstream blood vessel wall, increasing the risk of blood vessel puncture. Under normal circumstances, the distal landing point of the stent is located in the downstream area of the hemangioma. The diameter of the blood vessel in this area is usually smaller than the diameter of the blood vessel where the hemangioma is located, about the nominal diameter of the stent to be implanted. In other words, the length of the space that the distal end of the delivery system can extend is about the nominal diameter range of the stent to be implanted. In the present application, the stent delivery device is configured 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 a distance not exceeding half of the axial length of the force transmission member, the force transmission member can absorb the thrust fluctuation through elastic deformation to ensure the stability of the distal thrust. The force buffer component can effectively reduce the change in the force at the distal end, avoid the sudden forward movement of the distal guide wire or the delivery structure, and reduce the mechanical stimulation to the blood vessel wall. At the same time, it is defined that the distance between the distal end of the force buffer component and the distal end of the entire stent delivery device is less than or equal to the nominal diameter of the stent delivered by the stent delivery device, so as to shorten the structural length of the stent delivery device on the distal side of the force buffer component, forming a structurally compact "headless" stent delivery device. Thus, in the state where the force buffer component has not been 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 narrow spaces such as the distal end of the blood vessel and the bifurcation area can be effectively improved, the risk of accidentally touching the blood vessel wall can be reduced, and the navigation ability and adaptability in narrow or highly curved blood vessels can be enhanced, which is particularly suitable for high-demand clinical application scenarios such as bifurcated hemangiomas.

[0016] Specifically, in the present application, by providing a force buffer component, the force exerted by the distal end of the stent delivery device on the blood vessel wall is buffered, so that during the pulling and / or pushing process, the distal thrust always remains within a controllable low range, effectively reducing the mechanical stimulation to the blood vessel wall, reducing the risk of blood vessel injury caused by distal thrust fluctuation, and improving the safety of the stent implantation process.

[0017] The force buffer component of the present application can be understood as a structure that can convert the pushing force into deformation energy and absorb it. Its typical but not limited forms include springs, deformable spherical objects, deformable cage-like objects, etc. These structures can all absorb the excess thrust through elastic deformation during the pushing process, ensure the smoother transmission of the thrust at the distal end, thereby optimizing the stent release process, improving the implantation accuracy, and reducing surgical complications caused by thrust fluctuation.

[0018] The present application does not specifically limit the specific structure of the force buffering component, and any structure with mechanical buffering capability known in the art can be used in the present application.

[0019] Preferably, the structure of the force buffering component includes any one of a lantern-shaped grid structure, a spiral structure, and a wave-shaped structure.

[0020] Preferably, in the unconstrained state, the angle between the distal starting extension direction of the force transmission member and the axial center line is 5 to 70°, for example, 8°, 13°, 18°, 25°, 28°, 32°, 37°, 42°, 48°, 54°, 60°, 64°, 69°, etc.

[0021] In the unconstrained state, the angle between the force transmission component and the axial centerline is set to 5 to 70 degrees to ensure that the force transmission component can effectively decompose and buffer the axial thrust during the pushing process. When the proximal end of the push rod applies thrust, the thrust is transmitted axially to the force transmission component. Because the force transmission component forms a non-zero angle with the axial centerline, part of the thrust will be decomposed along the direction of the component, causing it to elastically deform, thereby absorbing part of the thrust fluctuation. If the angle is too small (such as less than 5 degrees), the axial force on the force transmission component is strong, and deformation requires a large starting force. The distal end may still produce large thrust fluctuations, thereby increasing the risk of distal advancement. If the angle is too large (such as exceeding 70 degrees), the elastic deformation space of the force buffer component becomes smaller, the distal thrust fluctuation range 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 to 70 degrees achieves an optimal balance between buffering thrust and maintaining pushing rigidity, which can effectively absorb 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 member and the axial centerline in this application is 5 to 70 degrees, this does not mean that angles less than 5 degrees or greater than 70 degrees cannot be used in this application. In appropriate application scenarios, angles outside the range of 5 to 70 degrees can still be used as optional technical solutions. For example, a structure with an angle less than 5 degrees is generally more suitable for situations where the vessel wall is more resilient or the distal push space is larger, while a structure with an angle greater than 70 degrees is suitable for scenarios where the vessel wall is less resilient or the distal push space is smaller.

[0023] In a specific embodiment, the force transmission member is made of a filamentous material with an elastic modulus of 30 to 180 GPa (such as 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 at least two combinations of superelastic materials and shape memory materials.

[0024] Preferably, when the axial thrust applied to the proximal end of the pusher rod causes the proximal end of the stent delivery device to move axially by a distance not exceeding half of the axial length of the force transmission member, the axial thrust fluctuation at the distal end of the stent delivery device remains within ≤50 mN, such as 45 mN, 40 mN, 36 mN, 32 mN, 26 mN, 20 mN, 18 mN, 12 mN, 8 mN, 5 mN, 2 mN, etc.

[0025] The axial thrust fluctuation at the distal end of the stent delivery device remaining within ≤50 mN can greatly reduce the damage to the blood vessel wall, improve the delivery safety of the stent delivery device, broaden the application scenarios of the stent delivery device, and can be applicable to the treatment of bifurcated blood vessel lesions.

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

[0027] Simulate the actual blood vessel environment, push the stent delivery device so that the distal end abuts against the distal force test position, then push a predetermined distance at the proximal end, measure the force value at the distal end of the stent delivery device, and record it to obtain the fluctuation range of the distal force value.

[0028] Exemplarily, the actual blood vessel environment can be simulated by a full-module push-pull force tester, and the force value at the distal end of the stent delivery device can be measured by a distal force sensor. The distal force test position is the probe of the distal force sensor.

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

[0030] The present application preferably uses a filamentous material with an elastic modulus of 30 to 180 GPa as the material of the force transmission member. The elastic modulus reflects the deformation resistance of the material. The materials within this range can not only provide sufficient deformation ability but also ensure good elastic recovery.

[0031] In terms of specific material selection, it is preferred to use superelastic materials or shape memory materials, or a combination of the two. For example, Nitinol alloy is a typical superelastic and shape memory alloy, which exhibits strong elastic deformation ability within a small deformation range and can quickly absorb and release thrust fluctuations. In addition, Nitinol alloy can also return to its original form within a certain temperature range, so that the force buffering component can maintain a stable shape and function after the stent is released. The material properties of Nitinol alloy enable the stent delivery device to adapt to the complex vascular environment and maintain good mechanical properties during clinical use.

[0032] As a specific embodiment, the force buffering component is a lantern-shaped grid structure, which is obtained by cross-weaving multiple strands of elastic wire into a hollow tube network structure and pre-forming a structure with two ends converging into a middle cavity, and the elastic wire is a force conduction component; or, the lantern-shaped grid structure is obtained by extending at least two strands of elastic wire side by side and pre-forming a structure with two ends converging into a middle cavity, and the elastic wire is a force conduction component.

[0033] The lantern-shaped grid structure is composed of multiple strands of elastic wire as force-conducting components, which are formed through a pre-forming process to converge at both ends and form a cavity in the middle. Preferably, the force-conducting components are distributed along the surface of the lantern-shaped structure along the meridian direction, or extend at an angle to the meridian direction.

[0034] The force-transmitting components are distributed along the meridians, extending from one end of the truss to the other, forming a regular axial support structure. This arrangement provides high axial rigidity while also enabling elastic deformation along the meridians when subjected to force, thereby buffering thrust fluctuations.

[0035] The force-transmitting components are arranged at an angle to the meridians, providing more flexible deformation characteristics. During the pushing process, this angle design allows the thrust to be more easily decomposed into multiple directions, allowing the lantern-shaped grid structure to more effectively distribute the load, thereby improving the efficiency of thrust buffering.

[0036] In one embodiment, the cross-woven hollow tubular mesh structure is formed by cross-weaving multiple strands of elastic thread. This weaving process creates a regular pattern of hollow meshes, with force-transmitting components extending at an angle to the warp direction. These meshes provide ample elastic deformation space, allowing the force-buffering components to evenly distribute the load and produce controlled deformation when subjected to thrust, effectively absorbing and buffering thrust fluctuations. This design ensures that even if the proximal thrust of the stent delivery device changes during delivery, the distal force remains within a relatively stable range, minimizing the impact of distal thrust on the vessel wall.

[0037] In another specific embodiment, the grid structure formed by arranging elastic filaments side by side is formed by arranging at least two elastic filaments side by side and forming a hollow structure with converging ends at both ends through a pre-forming process. The force transmission member can extend and distribute along the warp direction on the surface of the lantern-shaped structure, or can extend and distribute at a certain angle with the warp on the surface of the lantern-shaped structure. In this way, the arrangement of the force transmission member is more regular, and a more stable force buffering characteristic can be provided. During the pushing process, the axial thrust will be conducted along the direction of the elastic filament, and since the filament is distributed at a certain angle with the axis, part of the thrust will be converted into a lateral component force, causing the force buffering component to generate a controlled deformation, thereby absorbing the thrust fluctuation and avoiding a sudden increase in the force received at the distal end.

[0038] Preferably, a guiding portion is provided at the distal end of the force buffering component, and the guiding portion is preferably integrally designed with the converging end of the force transmission member.

[0039] To further optimize the stability of the distal end of the lantern-shaped grid structure, the present application preferably provides a guiding portion at the distal end of the force buffering component. The guiding portion is used to play a guiding role during the stent delivery process, enhance the distal stability of the delivery device, and reduce the probability of lateral displacement or uncontrolled displacement of the distal structure during the stent release process. The guiding portion of the present application can be connected to the distal end of the converging end of the force transmission component through a connection method (such as bonding, welding, etc.), or the converging end can be directly extended as the guiding portion. The guiding portion is preferably integrally designed with the converging end of the force transmission member, making the structure more compact, reducing additional component connections, and improving the overall mechanical properties.

[0040] The present application optimizes the construction method of the lantern-shaped grid structure, the arrangement form of the force transmission member, and the design of the guiding portion, ensuring that the stent delivery device can effectively buffer the thrust fluctuation during the stent release process, improve the distal stability, reduce the risk of blood vessel injury, and optimize the accuracy of stent implantation during the delivery and release processes.

[0041] As yet another specific embodiment, the lantern-shaped grid structure is obtained by engraving a metal tube into a hollowed-out grid structure and then pre-forming it into a structure with converging ends at both ends and a middle cavity, and the struts forming the hollowed-out grid are connected end to end to form a force transmission member.

[0042] By engraving a hollowed-out grid structure on the metal tube, the structural integrity of the grid can be maintained, good mechanical properties can be maintained, and the force transmission can be made more stable. In the hollowed-out grid, the struts are connected end to end to form a force transmission member. When a thrust is applied to the proximal end of the pusher rod, the thrust will be transmitted along these struts. Due to the special design of the strut structure, it can generate elastic deformation during the force application process, thereby absorbing the thrust fluctuation and reducing the instability of the distal thrust.

[0043] Preferably, a guide portion is provided at the distal end of the force buffer component, preferably integrally formed with the converging end of the force-conducting member. To further enhance distal stability of the delivery device, the present application preferably provides a guide portion at the distal end of the force buffer component. This guide portion serves to stabilize the front end trajectory of the delivery device, preventing deviation or uncontrolled displacement during delivery.

[0044] The guide portion and the converging end of the force transmission component are preferably designed as an integral whole, that is, the guide portion can be formed by extending the force transmission component, or directly processed and formed as an integral structure, thereby improving the overall mechanical stability of the stent delivery device and making the delivery device better controllable during the pushing and releasing process.

[0045] Preferably, the hollow grid is prepared by laser engraving and / or chemical etching.

[0046] The laser engraving process is suitable for a variety of high-performance metal materials, such as nickel-titanium alloy and cobalt-chromium alloy, and can ensure that the force buffer components have excellent elastic deformation ability and long-term durability.

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

[0048] As another specific embodiment, the force buffering component is an elastic structure predetermined to be formed into a spiral structure and / or a wavy structure, and a guide portion is provided at the distal end of the force buffering component, and the guide portion is extended in the axial direction.

[0049] Preferably, the spiral structure and / or wavy structure is obtained by a preforming process.

[0050] The spiral and / or wavy structures can both undergo elastic deformation when subjected to axial force, thereby absorbing part of the thrust through deformation during the pushing process, thereby reducing the fluctuation range of the distal thrust.

[0051] The helical structure, composed of a helical component made of an elastic material, can be compressed or stretched axially during the delivery process, allowing the thrust to be decomposed and buffered within the helical structure. This helical design allows the force buffer to gradually release accumulated energy after being subjected to force, thereby preventing sudden transmission of thrust and improving the distal stability of the stent delivery device.

[0052] The wavy structure is composed 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 the thrust fluctuations through deformation. The wavy structure provides a gentler force buffering effect, making it particularly suitable for stent delivery in tortuous vessels or narrow lesions.

[0053] Compared with rigid linear force buffering structures, spiral or wavy structures have better flexible buffering properties, so that the proximal thrust will not be directly and abruptly transmitted to the distal end, but will be gradually released through the deformation of the buffering structure, thereby reducing the force fluctuation at the distal end and preventing the distal end of the delivery device from advancing or causing mechanical damage to the blood vessel wall.

[0054] In order to improve the trajectory stability of the stent delivery device during the pushing and releasing process, especially the stability of the distal end, the present application provides an axially extending guide portion at the distal end of the force buffering component, so that the distal end of the delivery device can more easily maintain a stable propulsion direction and reduce the probability of deviation or rotation.

[0055] Both the spiral structure and the wavy structure are obtained through a pre-forming process to ensure that they have good deformation recovery capabilities during the pushing process and maintain stable mechanical properties.

[0056] Preferably, the length of the guide portion is less than or equal to the nominal diameter of the stent delivered by the stent delivery device. Preferably, the length of the guide portion is 0 to 0.8 times the nominal diameter of the stent delivered by the stent delivery device, and 0 means 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 conducting 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 and the force buffer. Sleeved over the distal end of the force buffer, the guide provides additional structural support, reducing the likelihood of unexpected lateral displacement or twisting of the distal end during delivery and release, thereby improving the predictability and accuracy of the delivery process. The guide facilitates uniform transmission of the thrust at the distal end, allowing the force buffer to more stably absorb thrust fluctuations, further reducing distal thrust fluctuations.

[0059] Preferably, the guide portion comprises a rigid ring and / or a flexible ring. In practice, the guide portion can be either rigid or flexible, depending on the specific application scenario. Typically, for high-precision stent delivery, a more rigid guide portion can be used to provide a more stable delivery trajectory. For tortuous vascular environments, a more compliant guide structure can be used to adapt to complex vascular morphology and reduce stress on the vessel wall.

[0060] Preferably, the rigid ring is a radiopaque ring; typically made of radiopaque material, its primary function is to provide more stable distal support and enhance visualization during intraoperative imaging guidance. The rigid ring prevents deformation of the guide during delivery, thereby increasing distal rigidity of the delivery device and enabling more controlled stent deployment.

[0061] Regarding the radiopaque material, no specific limitation is imposed in this application, and any radiopaque material that can be obtained by those skilled in the art can be used to prepare the radiopaque ring. Typically but not restrictively, such as platinum, platinum alloy, etc. These materials can be clearly visualized under X-ray or other medical imaging devices, which helps doctors to monitor the position of the delivery device and the stent release situation in real time during the operation, and improves the accuracy of the operation.

[0062] Preferably, the flexible ring is a flexible single ring or a helical winding structure, preferably a helical coil.

[0063] The design of the flexible ring is aimed at providing better compliance and softness to meet the delivery requirements of tortuous or vulnerable blood vessels. The flexible single ring can be made of a highly elastic material, which can provide a certain deformation ability during the pushing process to reduce the compression on the blood vessel wall. The flexible ring can also adopt a helical coil as the main form of the flexible ring. This structure has excellent axial flexibility and radial support, making it easier for the delivery device to pass through tortuous blood vessels, and at the same time providing appropriate support during stent release to avoid excessive protrusion at the distal end.

[0064] Preferably, the guiding part is made of a radiopaque material. During the interventional operation, the radiopaque material enables doctors to observe the specific position of the guiding part in real time through imaging devices such as X-ray, CT or MRI, ensuring that the delivery device and the stent are in an ideal implantation position, and improving the accuracy of implantation and the safety of the operation.

[0065] In the preferred embodiment of this application, by optimizing the structural design of the guiding part, it plays an important role in aspects such as stent delivery, intraoperative positioning, stent release and blood vessel protection, thereby improving the overall performance of the stent delivery device and ensuring the efficiency and safety of the interventional operation.

[0066] In an alternative embodiment, a buffer end is provided at the distal end of the guiding part. The Shore hardness D of the buffer end is 50-80, such as 55, 58, 63, 68, 75, etc., and the tensile property is 2%-150%, such as 3%, 16%, 33%, 55%, 73%, 95%, 113%, 135%, 148%, etc.

[0067] With the Shore hardness in the range of 50-80, on the one hand, the buffer end can maintain its shape when the guiding part is under load, and on the other hand, it has sufficient flexibility to cause necessary deformation when being impacted, absorb energy, and reduce the damage to the surrounding structure or biological tissue.

[0068] Tensile property indicators indicate the ductility of a material when subjected to tensile force. The range of 2% - 150% enables the material to meet the deformation requirements, being able to withstand minor deformations and also adapt to large-scale stretching without breaking. This allows the buffer end to more easily advance in tortuous blood vessels during transportation, improving its adaptability and overall durability under dynamic loads.

[0069] Preferably, the material of the buffer end is a biocompatible polymer glue or solder paste, preferably including ultraviolet curable glue or epoxy resin glue.

[0070] A second object of the present application is to provide a stent system, including:

[0071] Self-expanding stent;

[0072] Catheter;

[0073] The stent delivery device described in the first object, disposed within the catheter and extending axially, with the distal end of the stent delivery device loading the stent, and the proximal end for receiving a pushing force and conducting this 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 (≥1.5 mm) proximal to point X; a force buffer component is provided distal to the force change point A, for when the force change point A of the stent delivery device extends beyond the distal end of the catheter, within the range where the proximal advancement displacement of the stent delivery device is no greater than 1.5 mm, the fluctuation range of the pushing force transmitted to the distal end ≤ 50 mN.

[0075] During stent delivery, when the stent reaches near the distal end of the lesion, the stent release is usually controlled by retracting the catheter and pushing the stent delivery device. However, during this process, the pulling and / or pushing force applied to the stent delivery device at the proximal end will be transmitted to the distal end. Due to the tortuosity of the blood vessels, there is a loss in the conduction of the pulling and / or pushing force, resulting in a weakened response at the distal end and making the controllability of the distal end weaker. In addition, the tortuous blood vessel structure may cause the distal end of the stent delivery device to contact the blood vessel wall or even exert additional pressure, thereby increasing the risk of blood vessel injury. The present application buffers the force applied to the blood vessel wall at the distal end of the stent delivery device by providing a force buffer component at the distal end, controlling its fluctuation within ≤ 50 mN, so that during the pushing or retracting process, the force received at the distal end is within a controllable range, reducing the irritation and injury to the blood vessel wall and improving the safety of stent implantation.

[0076] When the proximal end of the stent delivery device is pushed a specific distance Y, usually due to factors such as blood vessel tortuosity, there will be a loss of the pushing stroke, resulting in the actual advancement distance of the distal end being less than Y. To ensure the effectiveness of the force buffer component, this application defines that the predetermined distance ≥ 1.5 mm to ensure that the force buffer component can be fully released and play its role. When point A of the stent delivery device extends beyond the distal end of the catheter, as long as the distal pushing displacement is within the range of 0 - 1.5 mm, the force fluctuation acting on the blood vessel wall can be ensured to be ≤ 50 mN. In addition, considering the existence of the pushing stroke loss, the actual advancement distance of the proximal end can usually exceed 1.5 mm without affecting the function of the force buffer component.

[0077] In the stent system, the force buffer component of the stent delivery device is arranged near the distal end. After the stent is delivered to the distal end of the lesion, the operator starts the pushing and / or retracting operation, and the stent and the distal end of the stent delivery device are gradually released. When the force change point A extends beyond the distal end of the catheter, the force buffer component is fully released. At this time, as long as the proximal advancement displacement does not exceed 1.5 mm, the force fluctuation range of the pushing force transmitted to the distal end can be ensured to be ≤ 50 mN. At the same time, since the force buffering range of the force buffer component does not exceed half of the axial length of the force transmission member, usually, the distal end of the stent will be flush with the distal end of the force buffer component or located between the proximal and distal ends of the force buffer component, which will assist the stent to expand better in the initial stage of stent release. More importantly, the setting of the predetermined distance ≥ 1.5 mm enables sufficient axial space to be provided for arranging the force buffer component after the force change point A extends beyond the distal end of the catheter, so that the force transmission member has sufficient length to achieve the buffering and decomposition of the force on the distal end of the stent delivery device.

[0078] It should be noted that during the stent delivery process, the stent delivery device is usually in a state of axial tension and radial compression. Only when part or all of the stent delivery device extends beyond the catheter, the released part will 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 member ≥ 3.0 mm.

[0080] When the axial length of the force transmission member ≥ 3.0 mm and the force change point A extends beyond the catheter, the distance between X and A will be greater than or equal to 3.0 mm, which can effectively ensure that after the force change point A of the stent delivery device extends beyond the distal end of the catheter, within the range where the proximal advancement displacement of the stent delivery device is not greater than 1.5 mm and does not exceed half of the axial length of the force transmission member.

[0081] Preferably, the self-expanding stent is sleeved on the stent delivery device in the delivery state, and the distal end of the self-expanding stent is located outside the force buffer component.

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

[0083] Preferably, the distal X point of the stent to be delivered is located between the force change point A and the distal end of the force buffer component. The distal end of the stent to be delivered is set at an appropriate position, which can, on the one hand, reduce the excessive distance that the stent delivery device extends beyond the distal end of the stent during the stent release process, causing damage to the inner wall of the blood vessel and increasing the operable space at the distal end of the stent delivery device; on the other hand, it can improve the controllability of the delivery of the stent to be delivered, especially the controllability of the distal end.

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

[0085] By providing a force buffer component in the stent delivery device, the present application effectively regulates the pushing force transmitted from its distal end to the blood vessel wall, ensuring that the force exerted by the stent delivery device on the blood vessel wall is always within a controllable low force value range during the pulling and / or pushing process, thereby significantly reducing the mechanical stimulation and potential damage risk to the blood vessel wall and further improving the safety of stent implantation. Description of the Drawings

[0086] Figure 1 Schematic structural diagram of the stent delivery device provided for Example 1;

[0087] Figure 2 Schematic structural diagram of the stent delivery device in the stent system provided for Example 1 when it has not extended out of the catheter;

[0088] Figure 3 Schematic structural diagram of the stent delivery device in the stent system provided for Example 1 when it has extended out of the catheter;

[0089] Figure 4 Measurement result of the pushing force fluctuation range at the distal end of the stent delivery device provided for Example 1;

[0090] Figure 5 Schematic structural diagram of the stent delivery device provided for Example 2;

[0091] Figure 6 Measurement result of the pushing force fluctuation range at the distal end of the stent delivery device provided for Example 2;

[0092] Figure 7 Schematic structural diagram of the stent delivery device provided for Example 3;

[0093] Figure 8 Measurement result of the pushing force fluctuation range at the distal end of the stent delivery device provided for Example 3. Detailed Description of the Embodiments

[0094] The following further explains the technical solution of the present invention in conjunction with 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 protection scope of the present invention.

[0095] In the description of the present invention, it should be understood that the terms "distal end" and "proximal end" in the text should be understood as observed from the direction of the surgical operator. The "distal end" is the end far from the surgical operator, and the "proximal end" is the end close to the surgical operator. The term "axial direction" in the text is the delivery direction of the stent, and the "axial center line" is the central axis extending axially, which is a fictional line and there is no real central axis in the technical solution.

[0096] The following further elaborates on the present application in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant invention and are not a limitation on the invention. Additionally, it should be noted that for the sake of convenience of description, only the parts related to the relevant invention are shown in the drawings.

[0097] Test example:

[0098] Use a full-module push-pull force tester (model RXDZ-TLN02G 10MMW) to test the push force transmission characteristics of the stent delivery device provided in the following embodiments. The specific steps are as follows:

[0099] (1) Assemble the 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-pull force tester to ensure that its path simulates the bending characteristics of the actual blood vessel environment. Arrange a distal force sensor at the distal end of the test path, and 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) Perform the test: Apply an axial thrust to the stent delivery device by the proximal push mechanism of the full-module push-pull force tester, and record the force value detected by the distal force sensor starting from when the distal end of the stent delivery device reaches the distal force sensor within the range of half of the axial length of the force conduction member (1.5 mm for Examples 1 to 3 and 2.5 mm for Example 4).

[0101] Example 1

[0102] As Figure 1 ( Figure 1 As shown in the structural schematic diagram of the stent delivery device provided for Example 1), Example 1 provides a stent delivery device 100, including:

[0103] An axially extending push rod 110;

[0104] A force buffer component provided at the distal end of the push rod 110; the force buffer component is a lantern-shaped grid structure 120, and the lantern-shaped grid structure 120 has a structure with both ends converging and a middle cavity in its natural state. The lantern-shaped grid structure 120 is formed by laser engraving a hollow pattern on a metal tube and then obtaining a structure with both ends converging and the middle expanding through heating and pre-forming. The frame struts of the hollow pattern are connected end to end to form a force conduction member 1212; the proximal end of the lantern-shaped grid structure 120 is fixedly connected to the distal end of the push rod 110, and the distal end of the lantern-shaped grid structure 120 is wound with a spiral coil 122, and a buffer end 123 is cured with an ultraviolet curing glue (model S2000-XLA) at the distal end point of the spiral coil 122. The spiral coil 122 and the buffer end 123 together serve as a guiding part.

[0105] The hollow pattern includes 4 radial columns 121a and connecting beams 121b connected between adjacent radial columns 121a. The connecting beams 121b are in an s shape, and both ends of the connecting beams 121b are connected to adjacent radial columns 121a. The radial columns 121a are force conduction members 1212.

[0106] In the lantern-shaped grid structure 120 formed after pre-forming, the included angle between the force conduction member 1212 and the axial center line is 40°. The metal tube is a nitinol alloy metal tube with an elastic modulus of 30 to 75 GPa.

[0107] Application Example 1

[0108] As Figures 2 - 3 ( Figure 2 Schematic diagram of the structure where the stent delivery device in the stent system provided in Example 1 does not extend out of the catheter, Figure 3 Schematic diagram of the structure where the stent delivery device in the stent system provided in Example 1 extends out of the catheter) shows that Application Example 1 provides a stent system, including:

[0109] A self-expanding stent 200 (nominal diameter 3.2 mm), a catheter 300, and the stent delivery device 100 provided in Example 1. The stent delivery device 100 extends inside the catheter 300, and the self-expanding stent 200 is loaded at 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 position of the buffer end 123.

[0110] During the operation, the operator pushes the push rod 110 of the stent delivery device 100 or retracts the catheter 300, so that the distal end of the stent delivery device 100 loaded with the self-expanding stent 200 extends out of the catheter 300. When point A of the stent delivery device 100 exceeds the distal end of the catheter, the force buffer component is completely released and is in a natural state (the two ends are constricted and there is a middle cavity). At this time, when the proximal end of the push rod 110 is pushed within a distance of 1.5 mm, the pushing force fluctuation range at the distal end of the stent delivery device 100 is 0-20 mN and 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 Figure 4 shown. The Proximal line is the detected value of the proximal force, and the Distal line is the detected value of the distal force.

[0112] Example 2

[0113] As Figure 5 ( Figure 5 being the structural schematic diagram of the stent delivery device provided in Example 2) shown, Example 2 provides a stent delivery device 100, which is only different from that in Example 1 in the setting of the structure of the force buffer component. Specifically:

[0114] The force buffer component is arranged at the distal end of the push rod 110 ( Figure 5 the entire length of the push rod 110 is not shown), and the lantern-shaped grid structure 120 is in a structure with two ends converging and a middle cavity in the natural state. The lantern-shaped grid structure 120 is obtained by cross-weaving 8 elastic silk threads 121c into a hollow pipe network structure, then constricting the two ends and bringing the two ends closer to make the middle expand to form a middle cavity, and then heating and pre-forming. The unconstrained part of the elastic silk thread 121c is the force conduction member 1211; after the two ends of the pipe network structure are constricted, 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 an ultraviolet curing glue (model S2000-XLA) is cured at the distal end point of the spiral coil 122 as the buffer end 123. The spiral coil 122 and the buffer end 123 together serve as the guiding part.

[0115] In the lantern-shaped grid structure 120 formed after pre-forming, the included angle between the force conduction member 1211 and the axial center line is 20°, and the force conduction member 1211 extends and distributes at a certain included angle with the meridional direction of the lantern-shaped grid structure, and the included angle is 60°. The elastic silk thread 121c is a nitinol metal wire with an elastic modulus of 30-75 GPa.

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

[0117] In alternative other embodiments, the elastic wire 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 non - restrictively, it includes metal wires such as nitinol and cobalt - chromium alloys, polymer wires with shape memory, or metal wires or polymer wires coated with functional coatings.

[0118] Application Example 2

[0119] The difference from Application Example 1 is only that the stent delivery device provided in Embodiment 2 is used to replace the stent delivery device 100 provided in Embodiment 1.

[0120] The testing method is the same as that in the test example, with the only difference being that the stent delivery device provided in Embodiment 1 is replaced by the stent delivery device provided in Embodiment 2. When the proximal end of the push rod 110 is pushed within a distance of 1.5 mm, the fluctuation range of the pushing force at the distal end of the stent delivery device 100 is 0 to 10 mN and can be controlled within 50 mN. According to the testing method of the test example, the measurement result of the fluctuation range of the pushing force at the distal end of the stent delivery device provided in Embodiment 2 is as Figure 6 shown. The Proximal line is the detected value of the proximal force, and the Distal line is the detected value of the distal force.

[0121] Embodiment 3

[0122] As Figure 7 ( Figure 7 being the structural schematic diagram of the stent delivery device provided in Embodiment 3) shown, Embodiment 3 provides a stent delivery device 100, the difference from Embodiment 1 being only the setting of the structure of the force buffer component, specifically:

[0123] The force buffer component is arranged at the distal end of the push rod 110. The force buffer component is a lantern - shaped grid structure 120. The lantern - shaped grid structure 120 has a structure with both ends converging and a middle cavity in its natural state. And the lantern - shaped grid structure 120 is obtained by heating and pre - shaping after 6 strands of elastic wires 121c are arranged side by side into a tubular structure, then the two ends are constricted and the two ends are brought close to each other to make the middle expand and form a middle cavity. The unconstrained part of the elastic wire 121c is the force - conducting member 1211; after the two ends of the tubular structure are constricted, 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 a UV - curable adhesive (model S2000 - XLA) is cured at the distal point of the spiral coil 122 as the buffer end 123. The spiral coil 122 and the buffer end 123 together serve as the guiding part.

[0124] In the lantern-shaped grid structure 120 formed after pre-forming, the angle between the force transmission member 1211 and the axial center line is 30°, and the force transmission member 1211 is distributed in the meridian direction on the surface of the lantern-shaped grid structure. The elastic silk thread 121c is a nitinol metal silk thread with an elastic modulus of 30-75 GPa.

[0125] Application Example 3

[0126] The difference from Application Example 1 is only that the stent delivery device provided in Example 2 is used to replace the stent delivery device 100 provided in Example 1.

[0127] The test method is the same as that in Test Example 1, the only difference being 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 within a distance of 1.5 mm, the pushing force fluctuation range at the distal end of the stent delivery device 100 is 0 to 33 mN and can be controlled within 50 mN. According to the test method of the test example, the measurement result of the pushing force fluctuation range at the distal end of the stent delivery device provided in Example 3 is as Figure 8 shown, the Proximal line is the detected value of the proximal force value, and the Distal line is the detected value of 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 are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements 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 stent delivery device, characterized in that, Comprising: An axially extending push rod; A force buffer member provided at the distal end of the push rod; the force buffer member includes at least one force conduction member, and the force conduction member forms a non-zero angle with the axial center line of the push rod; the distance between the distal end of the force buffer member and the overall distal end of the stent delivery device is less than or equal to the nominal diameter of the stent delivered by the stent delivery device; The force buffer member is configured 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 axially move a distance not exceeding half of the axial length of the force conduction member, the force conduction member absorbs the thrust fluctuation through elastic deformation.

2. The stent delivery device according to claim 1, wherein, The structure of the force buffer member includes any one of a lantern-shaped grid structure, a spiral structure, and a wavy structure; Preferably, in an unconstrained state, the included angle between the starting extension direction of the distal end of the force conduction member and the axial center line is 5 to 70°; Preferably, the force conduction member is made of a filamentous material with an elastic modulus of 30 to 180 GPa, preferably any one or a combination of at least two of a superelastic material and a shape memory material; Preferably, when the axial thrust applied to the proximal end of the push rod causes the proximal end of the stent delivery device to axially move a distance not exceeding half of the axial length of the force conduction member, the axial thrust fluctuation at the distal end of the stent delivery device remains within ≤50 mN.

3. The stent delivery device according to claim 1 or 2, characterized in that The lantern-shaped grid structure is obtained by cross-weaving multiple strands of elastic silk threads into a hollow grid structure and then pre-forming it into a structure with two ends converging and a middle cavity, and the elastic silk threads are the force conduction members; alternatively, the lantern-shaped grid structure is obtained by arranging at least 2 strands of elastic silk threads side by side and pre-forming it into a structure with two ends converging and a middle cavity, and the elastic silk threads are the force conduction members; Preferably, a guiding portion is provided at the distal end of the force buffer member, and the guiding portion is preferably integrally designed with the converging end of the force conduction member; Preferably, the force conduction members are distributed along the meridian direction on the surface of the lantern-shaped structure, or extend and distribute at an angle with the meridian direction.

4. The stent delivery device according to claim 1 or 2, characterized in that The lantern-shaped grid structure is obtained by engraving a metal tube into a hollow grid structure and then pre-forming it into a structure with two ends converging and a middle cavity, and the struts forming the hollow grid are connected end to end to form the force conduction members; Preferably, a guiding portion is provided at the distal end of the force buffer member, and the guiding portion is preferably integrally designed with the converging end of the force conduction member; Preferably, the hollow grid is prepared by laser engraving and / or chemical etching.

5. The stent delivery device according to claim 1 or 2, characterized in that The force buffer member is an elastic structure pre-formed into a spiral structure and / or a wavy structure, and a guiding portion is provided at the distal end of the force buffer member, and the guiding portion extends axially; Preferably, the spiral structure and / or the wavy structure is obtained by a pre-forming process.

6. The stent delivery device according to any one of claims 3 to 5, characterized in that, The length of the guiding portion is less than or equal to the nominal diameter of the stent delivered by the stent delivery device; Preferably, the guiding portion is sleeved on the distal end of the force buffer member; Preferably, the guiding portion includes a rigid ring and / or a flexible ring; Preferably, the rigid ring is a radio-opaque ring; Preferably, the flexible ring is a flexible single ring, a spiral winding structure, preferably a spiral coil; Preferably, the guiding part is made of a radiopaque material.

7. The stent delivery device according to any one of claims 3 to 6, characterized in that A buffer end is provided at the distal end of the guiding part, and the Shore hardness D of the buffer end is 50-80, and the tensile property is 2%-150%.

8. A bracket system, characterized in that, Comprising: A self-expanding stent; A catheter; The stent delivery device according to any one of claims 1 to 7, which is disposed in the catheter and extends axially. The distal end of the stent delivery device loads the stent, and the proximal end is used to receive a pushing force and conduct 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 member is provided on the distal side of the force change point A, and is used for when the force change point A of the stent delivery device exceeds the distal end of the catheter, within the range that the proximal end advancing displacement of the stent delivery device is not greater than 1.5 mm, the fluctuation range of the pushing force transmitted to the distal end ≤ 50 mN; The predetermined distance ≥ 1.5 mm.

9. The stent system according to claim 8, characterized in that, The axial length of the force conducting member ≥ 3.0 mm.

10. The stent system according to claim 8 or 9, characterized in that, The self-expanding stent is sleeved on the stent delivery device in the delivery state, and the distal end of the self-expanding stent is located outside the force buffer member.

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