Stent delivery system

Abstract

The invention provides a stent delivery system. The stent delivery system comprises a push rod and an outer sheath tube, at least part of the pushing rod is movably arranged in the outer sheath tube; a bracket is loaded between the push rod and the outer sheath tube; the pushing rod and the outer sheath tube can move relatively so that the support can move relative to the outer sheath tube. When at least part of the support is moved out of the outer sheath tube, the head end of the pushing rod moves towards the near end relative to the support, so that the far end of the pushing rod is located in the support. According to the stent conveying system, the phenomenon that the far end of the pushing rod penetrates through the lesion position in the stent releasing process can be improved, so that the risk of stimulating and damaging the blood vessel wall in the stent releasing process can be reduced, and the complexity and difficulty of operation are reduced.

Description

Technical Field

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

[0002] During stent interventions, stent implants are delivered and released via a delivery system. Figure 1 As shown, the delivery system is a microcatheter system for delivering a target stent 10 (e.g., an intracranial stent). After the target stent 10 is delivered to the position by the delivery system, the push rod 20 is pushed toward the distal end so that the target stent 10 follows the push rod 20 to move to the diseased site 40 of the blood vessel 30 (e.g., an intracranial blood vessel), and gradually expands from the head end of the microcatheter until it is attached to the inner wall of the blood vessel, thereby achieving the purpose of treatment. In addition, the delivery system can also be a preloaded delivery system for delivering a target stent (e.g., a carotid stent or a peripheral stent). The target stent is preloaded between the inner tube and the outer tube of the system before implantation. After the preloaded delivery system delivers the target stent to the diseased site via the catheter passage, the target stent can be released by withdrawing the outer tube or by pushing the inner tube forward.

[0003] However, no matter the target stent 10 is delivered via the microcatheter system or the preloaded delivery system, after the target stent 10 is delivered to the position and released, the distal end of the push rod 20 in the microcatheter system or the distal end of the inner tube in the preloaded delivery system needs to pass through the lesion site 40 to reach the distal end of the lesion site 40. Since the inner diameter of the blood vessel at the lesion site 40 is generally small and the blood vessel is relatively tortuous, the distal end of the push rod 20 or the distal end of the inner tube may cause irritation or damage to the inner wall of the blood vessel 30 during the process of passing through the lesion site 40, thereby increasing the risk of damage to the blood vessel 30. In addition, under normal circumstances, the farther the push rod 20 or the inner tube moves, the smaller the inner diameter of the blood vessel 30, the higher the possibility of tortuosity at the lesion site 40 of the blood vessel 30, and the higher the degree of tortuosity, the higher the risk of damaging the inner wall of the blood vessel 30. This disadvantage limits the operator's choice of the release position of the target stent 10 to a certain extent, and increases the complexity and difficulty of the operation.

[0004] Therefore, for those skilled in the art, how to design a stent delivery system that will not damage the inner wall of the blood vessel during the target stent release process is a technical problem that urgently needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a stent delivery system, which can improve the phenomenon that the distal end of the push rod passes through the lesion position during the stent release process, thereby reducing the risk of irritating and damaging the blood vessel wall during the stent release process, thereby reducing the complexity and difficulty of the operation.

[0006] To achieve the above-mentioned purpose, the present invention provides a stent delivery system, including a push rod and an outer sheath tube, at least a portion of the push rod can be movably placed in the outer sheath tube; the stent is loaded between the push rod and the outer sheath tube, and the push rod and the outer sheath tube can move relative to each other so that the stent moves relative to the outer sheath tube; when at least a portion of the stent is moved out of the outer sheath tube, the head end of the push rod moves toward the proximal end relative to the stent so that the distal end of the push rod is located in the stent.

[0007] Optionally, the push rod has a stretched state and an initial state, and can switch between the stretched state and the initial state; when the stent is completely loaded in the outer sheath tube, the push rod is in the stretched state; when at least part of the stent is moved out of the outer sheath tube, the push rod retracts from the stretched state so that the distal end of the push rod is located in the stent.

[0008] Optionally, the push rod includes a blocking member and a telescopic member, the distal end of the telescopic member is connected to the proximal end of the blocking member, at least part of the telescopic member is placed in the outer sheath tube, and the blocking member is used to block the distal end of the outer sheath tube;

[0009] When the stent is completely loaded in the outer sheath tube, the sealing member abuts against the outer sheath tube under the pulling of the telescopic member, and the telescopic member is in a stretched state after being subjected to the tensile force of the sealing member; when at least part of the stent is moved out of the outer sheath tube, the sealing member is separated from the distal end of the outer sheath tube, and the telescopic member retracts after the tensile force of the sealing member is removed.

[0010] Optionally, the telescopic member is a spring, and the length of the spring in the stretched state is less than twice the length of the spring in the initial state.

[0011] Optionally, the stent has a compressed state and a released state; when the stent is completely loaded in the outer sheath tube, the stent is in a compressed state; after at least part of the stent is moved out of the outer sheath tube, the stent expands from the compressed state to the released state;

[0012] The release force of the stent is greater than the contraction force of the spring, so that the stent can be moved out of the outer sheath tube from the gap between the blocking member and the outer sheath tube.

[0013] Optionally, a shortened length of the bracket when changing from a compressed state to a released state is greater than a shortened length of the telescopic member when changing from a stretched state to an initial state.

[0014] Optionally, the sealing member includes a head end and an embedded end, the proximal end of the head end is connected to the distal end of the embedded end, and the head end is placed outside the outer sheath tube; the embedded end is used to be inserted into the interior of the outer sheath tube; the head end is used to abut against the distal end of the outer sheath tube under the pulling of the telescopic member to seal the stent inside the outer sheath tube.

[0015] Optionally, the embedding end is used to be inserted into the inner cavity of the stent, so that the distal end of the stent is compressed between the embedding end and the outer sheath.

[0016] Optionally, the outer diameter of the embedded end matches the inner diameter of the outer sheath tube.

[0017] Optionally, the pushing rod also includes a pushing member, the distal end of the pushing member is connected to the proximal end of the telescopic member, the proximal end of the pushing member extends to the proximal end of the stent delivery device, and passes through the proximal end of the outer sheath tube, and at least part of the pushing member is placed in the outer sheath tube; the pushing member is used to drive the stent to move along its own axial direction to promote the separation of the sealing member from the outer sheath tube and move the stent out of the outer sheath tube.

[0018] Optionally, the conveying device further comprises a contact member, wherein the contact member contacts the stent and the pushing member respectively, and the pushing member is used to drive the stent to move axially along the outer sheath tube through the contact member.

[0019] Optionally, the contact member is configured as a thin sheet structure that can be located between the bracket and the pushing member, the contact member is connected to the distal outer wall of the pushing member, and the thin sheet structure can drive the bracket to move through static friction.

[0020] Optionally, the conveying device also includes a handle, the distal end of the handle is connected to the proximal end of the pushing member, and the proximal end of the handle extends out of the proximal end of the outer sheath tube; the handle is provided with a locking member for abutting the proximal end of the outer sheath tube, and the locking member is used to prevent the pushing member from moving toward the distal end under the pulling of the telescopic member.

[0021] The present invention provides a stent delivery system, which includes a push rod and an outer sheath tube; at least a portion of the push rod can be movably placed in the outer sheath tube; the stent is loaded between the push rod and the outer sheath tube; the push rod and the outer sheath tube can move relative to each other so that the stent moves relative to the outer sheath tube; when at least a portion of the stent is moved out of the outer sheath tube, the head end of the push rod moves toward the proximal end relative to the stent so that the distal end of the push rod is located in the stent.

[0022] With such configuration, when the stent reaches the target position and is gradually released, the head end of the push rod can move proximally relative to the stent so that the distal end of the push rod is always located in the inner cavity of the stent. In this way, the push rod does not need to pass through the lesion site during the stent release process, thereby preventing the push rod from causing irritation and damage to the blood vessel wall when passing through the lesion site, which helps to simplify the operation process, reduce the difficulty of stent release, and improve the safety and reliability during the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of a use scenario of a delivery system in the prior art, wherein the stent is pressed and gripped on the pushing rod;

[0024] Figure 2 It is a schematic diagram of a use scenario of a delivery system in the prior art, wherein the stent is anchored on the blood vessel wall after expansion;

[0025] Figure 3 It is a schematic diagram of the structure of a stent and a delivery device in a preferred embodiment of the present invention, wherein the stent is loaded in an outer sheath;

[0026] Figure 4 It is a schematic diagram of the structure of a stent and a delivery device in a preferred embodiment of the present invention, wherein the distal end of the stent is moved out of the outer sheath;

[0027] Figure 5 It is a simplified structural diagram of a part of the stent and a part of the delivery device in a preferred embodiment of the present invention, wherein the stent is in a released state;

[0028] Figure 6a It is a partial structural schematic diagram of a conveying system in a preferred embodiment of the present invention;

[0029] Figure 6b It is a partial structural schematic diagram of a conveying system in another preferred embodiment of the present invention;

[0030] Figure 7a for Figure 6a Deflection curves of various positions of the conveying system in the horizontal axis represent the deflection curves of the measuring position and the Figure 6a The distance from the rightmost end of the conveying system in the figure, and the ordinate represents the deflection corresponding to the measurement position;

[0031] Figure 7b for Figure 6b Deflection curves of various positions of the conveying system in the horizontal axis represent the deflection curves of the measuring position and the Figure 6b The distance from the rightmost end of the conveying system in the figure, and the ordinate represents the deflection corresponding to the measurement position;

[0032] Figure 8 It is a schematic diagram of the structure of the outer sheath and the handle in a preferred embodiment of the present invention.

[0033] In the figure: target stent 10; push rod 20; blood vessel 30; lesion site 40;

[0034] The support 1, the delivery device 2, the push rod 21, the blocking member 211, the head end 2111, the embedding end 2112, the telescopic member 212, the pushing member 213, the outer sheath 22, the contact member 23, the handle 24, the locking member 241, and the connecting member 242. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and in non-precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0036] The orientation or position relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or position relationship shown in the drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] As used in this specification, "distal end" generally refers to the end of the delivery device away from the operator; the term "proximal end" is opposite to the "distal end" and generally refers to the end of the delivery device close to the operator; the term "axial direction" refers to the extension direction of the axis of the stent, that is, the moving direction of the pushing member.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "fixation" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or a connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] The exemplary embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may complement or be combined with each other.

[0040] like Figure 3 and Figure 4 As shown, a preferred embodiment of the present invention provides a stent delivery system, including a stent 1 and a delivery device 2, wherein the delivery device 2 is used to deliver and release the stent 1. The delivery device 2 includes a push rod 21 and an outer sheath 22, wherein at least a portion of the push rod 21 is movably placed in the outer sheath 22. The stent is loaded between the push rod 21 and the outer sheath 22, and the stent 1 is preferably capable of being compressed and loaded in the accommodation space formed by the outer sheath 22 and the push rod 21; the push rod 21 and the outer sheath 22 can move relative to each other, so that the stent 1 moves relative to the outer sheath 22, that is, the stent 1 is released (i.e., the stent 1 is driven to move toward the distal end) and recovered (i.e., the stent 1 is driven to move toward the proximal end). When at least a portion of the stent 1 is moved out of the outer sheath 22, the head end of the push rod 21 moves toward the proximal end relative to the stent 1, specifically, the distal end of the push rod 21 moves toward the proximal end relative to the distal end of the stent 1, so that the distal end of the push rod 21 is located in the stent 1.

[0041] It should be understood that the push rod 21 can be set as a solid structure, or can have a hollow inner cavity for accommodating a guide wire. In a specific example, the push rod 21 is set as an inner sheath tube that can accommodate a guide wire.

[0042] Specifically, the operator can push the push rod 21, and the push rod 21 moves to drive the stent 1 to move toward the distal end relative to the outer sheath 22. After the stent 1 is separated from the outer sheath 22, it can spontaneously change from a compressed state to a released state, that is, the stent 1 can gradually expand after the pressure is removed, and the stent 1 in the released state can abut against the inner wall of the blood vessel, thereby achieving intraluminal treatment of the blood vessel. Figure 5 As shown, after the stent 1 is released, the delivery device 2 can be withdrawn.

[0043] Normally, the diseased location of the patient's blood vessel will become very narrow due to blockage. When configured in this way, when the stent 1 reaches the target location (i.e., the diseased location) and is gradually released, the head end 21 of the push rod can move proximally relative to the stent 1 so that the distal end of the push rod 21 is always located in the inner cavity of the stent 1. At this time, during the release of the stent 1, only the stent 1 passes through the diseased location of the blood vessel, and the push rod 21 does not need to pass through the diseased location. Therefore, the irritation and damage to the blood vessel wall caused by the push rod 21 when passing through the diseased location can be prevented, which helps to simplify the operation process, reduce the difficulty of releasing the stent 1, and improve the safety and reliability during the operation.

[0044] In a preferred embodiment, the push rod 21 has a stretched state and an initial state, and can switch between the stretched state and the initial state. Figure 2 ), the push rod 21 is in a stretched state. When at least part of the stent 1 is moved out of the outer sheath 22 (refer to Figure 3), that is, after the stent 1 is released, the push rod 21 retracts from the stretched state so that the distal end of the push rod 21 is located inside the stent 1. After the stent 1 moves a certain distance relative to the push rod 21, the push rod 21 can gradually return to the initial state. During the process of the push rod 21 returning to the initial state, the distal end of the push rod 21 is always located inside the stent 1.

[0045] In a specific embodiment, the stent 1 has a compressed state and a released state. When the stent 1 is completely loaded in the outer sheath tube 22 (refer to Figure 2 ), the stent 1 is in a compressed state. After at least part of the stent 1 is removed from the outer sheath 22 (refer to Figure 3 ), the stent 1 expands from a compressed state to a released state, thereby enabling the stent 1 to be transported and released.

[0046] Furthermore, the shortened length of the bracket 1 when it changes from the compressed state to the released state is greater than the shortened length of the telescopic member 212 when it changes from the stretched state to the initial state. Specifically, since the length of the push rod 21 in the stretched state is greater than the length of the push rod 21 in the initial state, the length of the push rod 21 is gradually shortened during the process of the push rod 21 returning from the stretched state to the initial state. The length of the bracket 1 when it is compressed is greater than the length of the bracket 1 after the compression force is removed, so the length of the bracket 1 is also gradually shortened during the process of the bracket 1 changing from the compressed state to the released state.

[0047] In more detail, the length of the push rod 21 in the stretched state is set to L1, and the length of the push rod 21 in the initial state is set to L2. At the same time, the length of the stent 1 in the compressed state is set to L3, and the length of the stent 1 in the released state is set to L4. In actual design, L3-L4<L1-L2 can be made, even if the shortened length of the stent 1 from the compressed state to the released state is less than the shortened length of the push rod 21 from the stretched state to the initial state, so that the distal end of the push rod 21 can be located in the inner cavity of the stent 1 during the release process of the stent 1.

[0048] Preferably, (L3-L4)*0.5<L1-L2, so as to ensure that the distal end of the pushing rod 21 is always located near the proximal end of the stent 1.

[0049] The present application does not limit the structure of the outer sheath 22. For example, the outer sheath 22 can be set to a double-layer structure (such as a double polymer layer) or a three-layer structure (such as an inner and outer polymer layer and a middle metal cutting layer or a metal braided layer).

[0050] Continue to refer to Figure 4In a preferred embodiment, the push rod 21 includes a blocking member 211 and a telescopic member 212, and the distal end of the telescopic member 212 is connected to the proximal end of the blocking member 211, for example, the distal end of the telescopic member 212 can be extended into and fixed in the blocking member 211. At least part of the telescopic member 212 is placed in the outer sheath 22, and the blocking member 211 is used to block the distal end of the outer sheath 22.

[0051] In one example, at least part of the blocking member 211 is placed outside the outer sheath 22 , and the maximum outer diameter of the blocking member 211 is greater than the inner diameter of the outer sheath 22 , so that the blocking member 211 can block the distal end of the outer sheath 22 .

[0052] Furthermore, when the stent 1 is completely loaded in the outer sheath 22, the blocking member 211 abuts against the outer sheath 22 under the pulling of the telescopic member 212, and the telescopic member 212 is in a stretched state after receiving the tensile force of the blocking member 211, and the push rod 22 is in the stretched state at this time. When at least part of the stent 1 is moved out of the outer sheath 22, that is, after the stent 1 is released, the blocking member 211 is separated from the distal end of the outer sheath 22, and the telescopic member 212 retracts after the tensile force of the blocking member 211 is removed. After the stent 1 moves a certain distance relative to the push rod 21, the push rod 21 can return to its initial state.

[0053] In more detail, since the blocking member 211 is in contact with the distal end of the outer sheath tube 22 under the pull of the telescopic member 212, the blocking member 211 cannot continue to move toward the proximal end, so that the telescopic member 212 is stretched under the action of the blocking member 211, and the telescopic member 212 has a tendency to return to its initial length. When the stent 1 gradually moves toward the distal end under the drive of the push rod 21, the blocking member 211 is separated from the distal end of the outer sheath tube 22, and the blocking member 211 is freed from the obstruction of the outer sheath tube 22 and can continue to move toward the proximal end under the pull of the telescopic member 212, so that the telescopic member 212 shrinks until it returns to its initial length.

[0054] In a specific example, the telescopic member 212 is a spring, and when the stent 1 is completely loaded in the outer sheath 22, the spring is in a stretched state; when the stent 1 is gradually released, the spring rebounds until it returns to its initial length. In this embodiment, the distal end of the spring is sleeved on the hollow pipe inside the blocking member 211.

[0055] Preferably, the length of the spring in the stretched state is less than twice the length of the spring in the initial state to ensure that the axial clearance of the spring in the stretched state is no more than twice the spring wire diameter, so that the spring can return to its initial length after the stretching force is removed, thereby avoiding the spring from being in a stretched state for a long time and causing irreversible deformation.

[0056] Preferably, the release force of the stent 1 is greater than the contraction force of the spring, so that the stent 1 can be moved out of the outer sheath 22 from the gap between the blocking member 211 and the outer sheath 22. It should be understood that the release force of the stent 1 refers to the pushing force of the stent 1 along its own axial direction toward the distal end in a compressed state, and the contraction force of the spring refers to the contraction force of the spring along its own axial direction toward the proximal end in a stretched state.

[0057] When configured in this way, after the stent 1 moves toward the distal end driven by the push rod 21, the pushing force of the stent 1 toward the distal end is greater than the contraction force of the blocking member 211 toward the proximal end under the tension of the spring. At this time, the stent 1 can push the blocking member 211 to move toward the distal end, so that the blocking member 211 is separated from the outer sheath 22, and the stent 1 is allowed to move out from the gap between the blocking member 211 and the outer sheath 22.

[0058] Reference Figure 6a and Figure 6b As shown, combined with Figure 4 In some embodiments, the blocking member 211 includes a head end 2111 and an embedding end 2112, and the proximal end of the head end 211 is connected to the distal end of the embedding end 2112. The head end 2111 is placed outside the outer sheath 22. The embedding end 2112 is used to be inserted into the inner part of the outer sheath 22. The head end 2111 is used to abut against the distal end of the outer sheath 22 under the pulling of the telescopic member 212 to block the stent 1 in the outer sheath 22, and the embedding end 2112 is placed inside the outer sheath 22.

[0059] In this embodiment, the outer peripheral area of ​​the head end 2111 gradually decreases from the proximal end to the distal end to facilitate the movement of the delivery device 2 in the body.

[0060] Reference Figure 6a As shown, in a specific embodiment, the embedded end 2112 is used to be inserted into the outer sheath tube 22, and the outer diameter of the embedded end 2112 matches the inner diameter of the outer sheath tube 22, that is, when the sealing member 211 abuts against the distal end of the outer sheath tube 22, the outer wall of the embedded end 2112 contacts the inner wall of the outer sheath tube 22. At this time, the stent 1 is completely loaded in the outer sheath tube 22 and is located at the proximal end of the embedded end 2112.

[0061] In actual design, the spring can have a higher rigidity, while the blocking member 211 can have a lower rigidity. Figure 7a As shown, when the blocking member 211 is designed as Figure 6a In the structure shown, the deflection at the connection between the blocking member 211 and the outer sheath tube 22 is relatively high (i.e., the connection has a relatively weak ability to resist bending), so the hardness of the connection between the blocking member 211 and the outer sheath tube 22 is relatively low. The blocking member 211 is easier to bend, which can improve the cornering guidance of the delivery device 2 and facilitate the delivery of the delivery device 2 in the body.

[0062] Reference Figure 6bAs shown, in another specific embodiment, the embedded end 2112 is used to be inserted into the inner cavity of the stent 1 so that the distal end of the stent 1 is compressed between the embedded end 2112 and the outer sheath 22. The design of the embedded end 2112 helps to fix the stent 1 in the outer sheath 22, thereby ensuring the stability of the entire delivery system.

[0063] Similarly, in actual design, the spring can have a higher rigidity, while the blocking member 211 can have a lower rigidity. Figure 7b As shown, when the blocking member 211 is designed as Figure 6b In the structure shown, the deflection at the connection between the blocking member 211 and the outer sheath tube 22 is relatively low (i.e., the connection has a stronger ability to resist bending), so the hardness of the connection between the blocking member 211 and the outer sheath tube 22 is relatively high and the possibility of bending is relatively low, so that the transition from the rigid spring to the flexible blocking member 211 at the distal end of the conveying system is smoother, thereby reducing the risk of excessive bending of the spring.

[0064] In actual use, the operator can select a sealing member 211 structure with higher hardness or better guidance according to needs to ensure the safety and reliability of the operation.

[0065] Further reference Figure 4 The push rod 21 also includes a pushing member 213, the distal end of the pushing member 213 is connected to the proximal end of the telescopic member 212, and the proximal end of the pushing member 213 extends to the proximal end of the conveying device 2, and passes through the proximal end of the outer sheath 22. At least part of the pushing member 213 is placed in the outer sheath 22. The pushing member 213 is used to drive the stent 1 to move along its own axial direction, so as to cause the blocking member 213 to separate from the outer sheath 22, and move the stent 1 out of the outer sheath 22. In actual operation, after the conveying device 2 is implanted at the lesion site, the operator can push or pull the pushing member 213 to drive the stent 1 to move toward the distal end relative to the outer sheath 22, thereby achieving the release and recovery of the stent 1.

[0066] The present application does not limit the structure of the pusher 213. Preferably, the pusher 213 is a push rod, and the proximal end of the spring is connected to the push rod (for example, it can be sleeved on the push rod or embedded in the push rod). In one example, the pusher 213 can be set as a polymer tube or a tubular structure formed by splicing multiple polymer tubes of different materials in their own axial direction. In another example, the pusher 213 can also be set as a tubular structure formed by splicing a metal tube and a polymer tube in their own axial direction.

[0067] Continue to refer to Figure 4 As shown, the conveying device 2 further includes a contact member 23 , which contacts the stent 1 and the push member 213 respectively. The push member 213 is used to drive the stent 1 to move axially along the outer sheath tube 22 through the contact member 23 .

[0068] As a preferred embodiment, the contact member 23 is configured as a thin film structure (such as a push gasket) that can be located between the bracket 1 and the push member 213. The contact member 23 is connected to the distal outer wall of the push member 213, and the thin film structure can drive the bracket 1 to move through static friction.

[0069] In this embodiment, the contact member 23 is arranged at the distal end of the pushing member 213 and respectively abuts against the inner wall of the bracket 1 and the outer wall of the pushing member 213. After the operator moves the pushing member 213, the static friction between the contact member 23 and the bracket 1 can be used to recover and release the bracket 1.

[0070] Reference Figure 8 As shown, the delivery device 2 also includes a handle 24, the distal end of which is connected to the proximal end of the pusher 213, and the proximal end of the handle 24 extends out of the proximal end of the outer sheath 22. The handle 24 is provided with a locking member 241 for abutting against the proximal end of the outer sheath 22, and the locking member 241 is used to prevent the pusher 213 from moving toward the distal end under the pull of the telescopic member 212, so as to ensure that the push rod 21 is in a stretched state when the stent 1 is fully loaded in the outer sheath 22. In this case, the locking member 241 can cooperate with the blocking member 211, so that the stent 1 can be loaded in the outer sheath 22 and the push rod 22 is in a stretched state, thereby ensuring the stability of the delivery system.

[0071] More specifically, the handle 24 includes a connecting rod 242 (see Figure 8 ), one end of the connecting rod 242 is connected to the pushing member 213, and the other end extends out of the proximal end of the outer sheath tube 22, and the locking member 241 is arranged on the connecting rod 242, and the outer diameter of the locking member 241 is larger than the inner diameter of the outer sheath tube 22 to prevent the connecting rod 242 and the pushing member 213 from moving toward the distal end driven by the telescopic member 212.

[0072] In summary, the present invention provides a stent delivery system, in which, during the process of the stent 1 reaching the target position and being gradually released, the head end of the push rod 21 can move proximally relative to the stent 1 so that the distal end of the push rod 21 is always located in the inner cavity of the stent 1. At this time, during the release of the stent 1, the push rod 21 does not need to pass through the lesion position, thereby preventing the push rod from causing stimulation and damage to the blood vessel wall when passing through the lesion position, which helps to simplify the operation process, reduce the difficulty of releasing the stent, and improve the safety and reliability during the operation.

[0073] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the protection scope of the present invention.

Claims

1. A stent delivery system, characterized in that: It includes a push rod and an outer sheath tube; at least part of the push rod can be movably placed in the outer sheath tube; a stent is loaded between the push rod and the outer sheath tube; the push rod and the outer sheath tube can move relative to each other so that the stent moves relative to the outer sheath tube; when at least part of the stent is moved out of the outer sheath tube, the head end of the push rod moves toward the proximal end relative to the stent so that the distal end of the push rod is located in the stent.

2. The stent delivery system according to claim 1, wherein: The push rod has a stretched state and an initial state, and can switch between the stretched state and the initial state; when the stent is completely loaded in the outer sheath tube, the push rod is in the stretched state; when at least part of the stent is moved out of the outer sheath tube, the push rod retracts from the stretched state so that the distal end of the push rod is located in the stent.

3. The stent delivery system according to claim 1, wherein: The push rod includes a blocking member and a telescopic member, the distal end of the telescopic member is connected to the proximal end of the blocking member, at least part of the telescopic member is placed in the outer sheath tube, and the blocking member is used to block the distal end of the outer sheath tube; When the stent is completely loaded in the outer sheath tube, the sealing member abuts against the outer sheath tube under the pulling of the telescopic member, and the telescopic member is in a stretched state after being subjected to the tensile force of the sealing member; when at least part of the stent is moved out of the outer sheath tube, the sealing member is separated from the distal end of the outer sheath tube, and the telescopic member retracts after the tensile force of the sealing member is removed.

4. The stent delivery system according to claim 3, characterized in that: The telescopic member is a spring, and the length of the spring in the stretched state is less than twice the length of the spring in the initial state.

5. The stent delivery system according to claim 4, characterized in that: The stent has a compressed state and a released state; when the stent is completely loaded in the outer sheath tube, the stent is in a compressed state; after at least part of the stent is moved out of the outer sheath tube, the stent expands from the compressed state to the released state; The release force of the stent is greater than the contraction force of the spring, so that the stent can be moved out of the outer sheath tube from the gap between the blocking member and the outer sheath tube.

6. The stent delivery system according to claim 5, characterized in that: The shortened length of the bracket when changing from a compressed state to a released state is greater than the shortened length of the telescopic member when changing from a stretched state to an initial state.

7. The stent delivery system according to claim 6, wherein: The sealing member includes a head end and an embedded end, the proximal end of the head end is connected to the distal end of the embedded end, and the head end is placed outside the outer sheath tube; the embedded end is used to be inserted into the interior of the outer sheath tube; the head end is used to abut against the distal end of the outer sheath tube under the pulling of the telescopic member to seal the stent inside the outer sheath tube.

8. The stent delivery system according to claim 7, wherein: The embedding end is used to be inserted into the inner cavity of the stent, so that the distal end of the stent is compressed between the embedding end and the outer sheath.

9. The stent delivery system according to claim 7, wherein: The outer diameter of the embedded end matches the inner diameter of the outer sheath tube.

10. The stent delivery system according to claim 3, wherein: The push rod further includes a push member, the distal end of which is connected to the proximal end of the telescopic member, the proximal end of which extends to the proximal end of the stent delivery device and passes through the proximal end of the outer sheath tube, and at least part of the push member is placed in the outer sheath tube; The pushing member is used to drive the stent to move along its own axial direction, so as to cause the blocking member to separate from the outer sheath tube and move the stent out of the outer sheath tube.

11. The stent delivery system according to claim 10, wherein: The conveying device further comprises a contact member, wherein the contact member is in contact with the stent and the pushing member respectively, and the pushing member is used for driving the stent to move along the axial direction of the outer sheath tube through the contact member.

12. The stent delivery system according to claim 11, wherein: The contact member is configured as a thin sheet structure that can be located between the bracket and the pushing member, the contact member is connected to the distal outer wall of the pushing member, and the thin sheet structure can drive the bracket to move through static friction.

13. The stent delivery system according to claim 10, wherein: The conveying device also includes a handle, the distal end of the handle is connected to the proximal end of the pushing member, and the proximal end of the handle extends out of the proximal end of the outer sheath tube; the handle is provided with a locking member for abutting against the proximal end of the outer sheath tube, and the locking member is used to prevent the pushing member from moving toward the distal end under the pulling of the telescopic member.

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