Limiting structure of umbrella-shaped vena cava filter

Abstract

The invention provides a limiting structure of an umbrella-shaped vena cava filter, the limiting structure is applied to a vena cava filter conveying system, the vena cava filter conveying system comprises a filter which is arranged in an inner cavity of an intervention sheath tube in a folded state, and a plurality of open grooves extending in the axial direction are formed in the limiting structure in the circumferential direction; the second supporting arm and the third supporting arm respectively form a second limiting part and a third limiting part which extend into the open groove along the first direction, and the second limiting part and the third limiting part abut against the side groove wall of the open groove along the two circumferential sides and are in circumferential limiting fit with the open groove; the second limiting part and the third limiting part abut against the inner wall of the intervention sheath tube through shape memory restoring force of the second limiting part and the third limiting part, and radial gaps exist between the second limiting part and the bottom groove wall of the open groove and between the third limiting part and the bottom groove wall of the open groove. The problem that in the prior art, the second supporting arm and the third supporting arm are prone to interference or scratching in the withdrawing or releasing stage is solved, precise unfolding and safe withdrawing of the filter are achieved, and the instrument loss and the vascular injury risk are reduced.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a limiting structure for an umbrella-shaped vena cava filter. Background Technology

[0002] For patients at high risk of pulmonary embolism, implanting a filter in the inferior vena cava to capture thrombi can effectively prevent thrombus dislodgement and entry into the lungs, thereby reducing the incidence of pulmonary embolism. Existing inferior vena cava filter delivery systems (e.g., CN119970296A) include: a delivery sheath, a sealing assembly, a pushing assembly, and a filter; the sealing assembly is disposed proximally to the delivery sheath, the filter is housed within the lumen of the delivery sheath, and the pushing assembly extends continuously into the lumen of the sealing assembly and the delivery sheath, driving the filter to move relative to the delivery sheath; a limiting member is disposed distally to the pushing assembly; the filter is constructed with multiple sets of circumferentially spaced, equidistant support structures whose length increases along a first direction; the support structures are held in a retracted state against the radial direction between the delivery sheath and the limiting member, and the retracted support structures are moved within the lumen of the delivery sheath along the first direction or in a second direction opposite to the first direction by the pushing action of the limiting member.

[0003] However, the aforementioned prior art relies on the radial restraint of the second and third support arms by the limiting member and the inner wall of the delivery sheath (which only relies on friction to form a passive constraint and cannot resist circumferential disturbances during movement). This fails to lock the circumferential position of the second and third support arms. As the second and third support arms move in the delivery sheath along the first direction (retraction direction) or the second direction (release direction), the second support arm may circumferentially shift to the preset path of the third support arm. This causes the third support arm to make contact interference before the second support arm is fully extended, thereby interfering with the deployment posture of the filter and ultimately affecting the structural stability of the filter after precise positioning. Furthermore, in the existing technology, the second and third support arms lack circumferential guidance when retracting the filter. This may cause the second and third support arms to be tilted and retracted due to circumferential offset (for example, the barbs of the second support arm are circumferentially tilted towards the inner wall of the delivery sheath). As a result, when the second and third support arms retract, the barbs or anchors are likely to scrape the inner wall of the delivery sheath, or even rub against the blood vessel wall when passing through the distal opening of the delivery sheath. This not only increases the wear and tear on the device, but also increases the risk of damage to the vascular intima. Summary of the Invention

[0004] The purpose of this invention is to provide a limiting structure for an umbrella-shaped vena cava filter, especially to solve the problem that the second and third support arms are prone to interference or scraping during the retraction or release phase in the prior art, thereby achieving precise deployment and safe retraction of the filter and reducing the risk of device wear and vascular damage.

[0005] The present invention provides a limiting structure for an umbrella-shaped vena cava filter, applied to a vena cava filter delivery system, the vena cava filter delivery system comprising:

[0006] An interventional sheath containing a filter within its lumen;

[0007] An air extraction assembly is disposed at the proximal end of the interventional sheath;

[0008] A control component extends axially continuously into the inner cavity of the suction component and the intervention sheath and connects to the filter to drive the filter to move bidirectionally along the axial direction.

[0009] The limiting structure is fixed to the far end of the control component and connected to the filter;

[0010] The filter is constructed with a plurality of first arms, a plurality of second arms and a plurality of third arms distributed circumferentially, wherein the axial lengths of the first arms, the second arms and the third arms increase sequentially along a first direction.

[0011] The filter is disposed in the inner cavity of the interventional sheath in a retracted state. The limiting structure forms a plurality of slots extending axially in the circumferential direction. The second arm and the third arm respectively form a second limiting part and a third limiting part extending into the slots in the first direction. The second limiting part and the third limiting part abut against the side wall of the slot on both sides in the circumferential direction and form a circumferential limiting fit with the slot.

[0012] The second limiting part and the third limiting part abut against the inner wall of the intervention sheath through their shape memory restoring force, and both the second limiting part and the third limiting part have a radial gap with the bottom wall of the groove.

[0013] According to the present invention, in some embodiments, the second limiting portion forms a first strip-shaped abutment surface extending axially on the side away from the slot, and the third limiting portion forms a second strip-shaped abutment surface extending axially on the side away from the slot. The first strip-shaped abutment surface and the second strip-shaped abutment surface are in line contact with the inner wall of the interventional sheath through the shape memory restoring force.

[0014] According to the present invention, in some embodiments, the number of slots is the sum of the total number of the second arm and the third arm, a single slot accommodates only one second limiting part or one third limiting part, and the circumferential spacing angle of adjacent slots is equal.

[0015] According to the present invention, in some embodiments, the cross-section of the side groove wall of the slot is an arc shape that protrudes or is recessed into the slot, and the surfaces of the second limiting part and the third limiting part that abut against the side groove wall are both arc surfaces adapted to the arc shape.

[0016] According to the present invention, in some embodiments, the limiting structure is made of a medical elastic material.

[0017] According to the present invention, in some embodiments, the filter includes a head end, and the first arm, the second arm and the third arm extend from the rear side of the head end along the first direction.

[0018] The first arm, the second arm, and the third arm are distributed at equal intervals along the circumference.

[0019] According to the present invention, in some embodiments, the first support arm includes: a first branch and a second branch that extend continuously relative to the central axis of the filter in a direction away from the central axis, and a third branch that connects the second branch and extends continuously relative to the central axis of the filter in a direction close to the central axis.

[0020] The connection between the second branch and the third branch has an arc-shaped transition.

[0021] According to the present invention, in some embodiments, the overall profile of the second arm is arc-shaped, the free end of the second arm is provided with barbs that bend radially outward for anchoring on the vessel wall, and the barbs are formed at the proximal end of the second limiting portion.

[0022] According to the present invention, in some embodiments, the overall outline of the third arm is a linear structure, and the free end of the third arm extends along the first direction to form an anchor for anchoring on the blood vessel wall, the anchor being formed at the proximal end of the third limiting portion.

[0023] According to the present invention, in some embodiments, the angle at which the first branch extends in a direction away from the central axis of the filter is greater than the angle at which the second arm extends in a direction away from the central axis of the filter.

[0024] The limiting structure of the umbrella-shaped vena cava filter according to the present invention has the following beneficial technical effects: by the abutting of the side wall of the slotted part with the circumferential sides of the second limiting part and the abutting of the side wall of the slotted part with the circumferential sides of the third limiting part, the second arm and the third arm can be fixed at a preset circumferential interval position, ensuring that the second arm and the third arm always move along their respective preset paths, avoiding cross interference between the second arm and the third arm, and strictly unfolding in the blood vessel in the order of unfolding the second arm first and then the third arm, so that the filter forms a stable umbrella-shaped structure after precise positioning, ensuring uniform thrombus capture gap, thereby stably performing the thrombus capture function. Furthermore, during filter retraction, the grooved side wall abuts against the circumferential sides of the second limiting part, and the grooved side wall abuts against the circumferential sides of the third limiting part, providing axial guidance for the second and third arms. This ensures that the second and third arms always retract in a direction parallel to the axis of the interventional sheath, preventing the barbs or anchors from scraping the inner wall of the interventional sheath or the vessel wall due to circumferential deviation. This reduces the risk of instrument wear and vascular damage during retraction, achieving safe and precise retraction of the filter. Attached Figure Description

[0025] Figure 1 This is an overall schematic diagram of a vena cava filter delivery system that includes the limiting structure of the umbrella-shaped vena cava filter disclosed in this invention;

[0026] Figure 2 A schematic diagram of a vena cava filter delivery system, omitting the interventional sheath and aspiration cannula;

[0027] Figure 3 A cross-sectional view of the filter being housed in a retracted state within the interventional sheath;

[0028] Figure 4 This is an overall schematic diagram of the connection between the filter and the limiting mechanism, wherein both the second limiting part and the third limiting part extend into the slot;

[0029] Figure 5 This is a schematic diagram of a filter and a limiting mechanism housed in an interventional sheath, wherein the second limiting part and the third limiting part both extend into the groove and abut against the inner wall of the interventional sheath.

[0030] Figure 6 This is a schematic diagram of the filter in its deployed state;

[0031] Figure 7 In another embodiment, a schematic diagram shows the filter and the limiting mechanism housed in the intervention sheath, wherein the cross-section of the side wall of the slot is an arc shape protruding into the slot. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0033] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar words used in this invention specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "inner," "outer," "upper," "lower," "far," "near," "front," and "rear" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] The accompanying drawings in this disclosure are not drawn to scale, and the specific dimensions and quantity of each structure can be determined according to actual needs. The drawings described in this disclosure are only structural schematic diagrams.

[0035] It should be noted that "axial" refers to Figure 1 The direction indicated by the axis Q of the interventional sheath 10. "Radial" refers to the direction J passing through axis Q.

[0036] Please refer to Figures 1 to 7 A specific embodiment of the limiting structure 31 of the umbrella-shaped vena cava filter is disclosed. The limiting structure 31 of the umbrella-shaped vena cava filter is applied to a vena cava filter delivery system 100, which includes: an interventional sheath 10, an air aspiration assembly 20, a control assembly 30, and a filter 40.

[0037] The interventional sheath 10 houses a filter 40 within its lumen. An aspiration assembly 20 is positioned proximal to the interventional sheath 10. A control assembly 30 extends axially continuously to the aspiration assembly 20 and the lumen of the interventional sheath 10, connecting to the filter 40, to drive the filter 40 bidirectionally along the axial direction. Figure 3 The movement is indicated by the middle arrows X1 and X2. The limiting structure 31 is fixed at the far end of the control component 30 and connected to the filter 40.

[0038] The filter 40 is configured with a plurality of first arms 41, a plurality of second arms 42, and a plurality of third arms 43 that are circumferentially distributed. The axial lengths of the first arm 41, the second arm 42, and the third arm 43 increase sequentially in the first direction. The length of the first arm 41 is less than the length of the second arm 42, and the length of the second arm 42 is less than the length of the third arm 43.

[0039] The filter 40 is disposed in the inner cavity of the intervention sheath 10 in a collapsed state. The limiting structure 31 forms a plurality of axially extending slots 311 circumferentially. The second arm 42 and the third arm 43 respectively form second limiting portions 421 and third limiting portions 431 that extend into the slots 311 in the first direction (i.e., Figure 3 and Figure 4 the direction shown by the arrow X1 in

[0040] See Figures 3 to 5 As shown, the limiting structure of the umbrella-shaped inferior vena cava filter provided by the present invention realizes the release and offset calibration of the filter 40 during the operation according to the following process. First, a guide wire (not shown) is introduced into the target blood vessel to provide a guiding path for the filter 40. After evacuating the air inside the intervention sheath 10 through the air extraction component 20, the intervention sheath 10 is sent along the guide wire to the target position in the inferior vena cava. The inner cavity of the intervention sheath 10 accommodates the filter 40 in a collapsed state. At this time, the first arm 41 of the filter 40 is radially held between the limiting structure 31 and the inner wall 102 of the intervention sheath 10. The second limiting portion 421 and the third limiting portion 431 are both embedded in the slots 311 of the limiting structure 31, and there are radial clearances (L1, L2) between the second limiting portion 421 and the third limiting portion 431 and the bottom slot wall 3112 of the slots 311, and they abut against the inner wall 102 of the intervention sheath 10 through the shape memory restoring force to form a stable constraint state.

[0041] When the operator finds that the filter 40 reaches the target position through the imaging device, the operator applies a thrust along the second direction through the operation control component 30. The thrust is axially transmitted to the limiting structure 31 through the control component 30. By the circumferential sides of the side slot wall 3111 of the slot 311 abutting against the second limiting portion 421 and the circumferential sides of the side slot wall 3111 of the slot 311 abutting against the third limiting portion 431, the limiting structure 31 can form a force on the filter 40 along the second direction (i.e., Figure 3The driving force (in the direction indicated by the middle arrow X2) drives the filter 40 to overcome the contact friction between the first arm 41 and the limiting structure 31, the contact friction between the first arm 41 and the inner wall 102 of the intervention sheath 10, the contact friction between the second limiting part 421 and the inner wall 102 of the intervention sheath 10, and the contact friction between the third limiting part 431 and the inner wall 102 of the intervention sheath 10 in the retracted state, so as to drive the filter 40 to move along the inner cavity of the intervention sheath 10 toward the distal end of the intervention sheath 10 (i.e., move along the second direction).

[0042] During movement, the limiting structure 31 moves synchronously with the control component 30. The side wall 3111 of the slot 311 always abuts against the circumferential sides of the second limiting part 421 and the third limiting part 431, and the circumferential limiting cooperation prevents the filter 40 from twisting during movement, avoiding the second arm 42 and the third arm 43 from deviating from their respective preset unfolding angles due to circumferential offset. At the same time, since the axial lengths of the second limiting part 421 and the third limiting part 431 are both less than the axial length of the slot 311, the second limiting part 421 and the third limiting part 431 can slide freely within the slot 311, which neither hinders the axial movement of the filter 40, but also maintains circumferential constraint, ensuring that after the filter 40 is released from the interventional sheath 10, the second arm 42 and the third arm 43 can unfold in the blood vessel at their respective preset angles. As the filter 40 continues to move toward the distal end of the interventional sheath 10, the first arm 41 extends out from the distal opening 101 of the interventional sheath 10. After being freed from the radial constraint of the interventional sheath 10, it unfolds and conforms to the blood vessel wall through shape memory restoring force, achieving initial positioning. As the control component 30 continues to be pushed, the second arm 42 and the third arm 43 successively detach from the interventional sheath 10 and unfold. At this point, all arms of the filter 40 have unfolded and are fixed in the target position to perform the thrombus capture function.

[0043] If the operator detects a displacement of the filter 40 via imaging equipment during release, before the first arm 41 is fully extended (i.e., before the end of the first arm 41 in the second direction disengages from the distal opening 101 of the interventional sheath 10), the operator can first stop pushing the control component 30 in the second direction and then slowly pull the control component 30 in the first direction to retract it. The pulling force is transmitted through the limiting structure 31 to drive the filter 40 to move slowly in the second direction, and the first arm 41 gradually retracts into the interventional sheath 10. During the retraction process, since the second limiting part 421 and the third limiting part 431 both have radial gaps with the bottom groove wall 3112 of the slot 311, the limiting structure 31 cannot apply radial compression to the second arm 42 and the third arm 43. Therefore, it is not necessary to overcome the compression resistance of the limiting structure 31 on the second arm 42 and the third arm 43. The second arm 42 and the third arm 43 are only radially constrained by the inner wall 102 of the interventional sheath 10. It is only necessary to overcome the contact friction between the second limiting part 421 and the inner wall 102 of the interventional sheath 10, the contact friction between the third limiting part 431 and the inner wall 102 of the interventional sheath 10, and the contact friction between the first arm 41 being radially held against the limiting structure 31 and the inner wall 102 of the interventional sheath 10, thus reducing the retraction resistance. For example, during the calibration of the filter 40 and the target position, the length of the distal opening 101 of the first arm 41 extending out of the interventional sheath 10 can be observed through an imaging device. The reduction in the length of the distal opening 101 of the first arm 41 extending out of the interventional sheath 10 is used as the calibration basis. For example, if the filter 40 is offset from the target position by 3 mm, when it is observed that the length of the distal opening 101 of the first arm 41 extending out of the interventional sheath 10 has decreased by 3 mm (i.e., the proximal 3 mm portion of the first arm 41 is retracted into the interventional sheath 10), the pulling control component 30 is stopped. At this time, the filter 40 has moved 3 mm along the first direction towards the distal opening 101 of the interventional sheath 10 to solve the problem of the offset between the filter 40 and the target position. After the filter 40 is aligned with the target position, the control component 30 is slowly pushed along the second direction to release the first arm 41 again. During this process, the circumferential constraint of the slot 311 on the second limiting part 421 and the third limiting part 431 continues to act to ensure that when the second arm 42 and the third arm 43 are released, the second arm 42 and the third arm 43 can extend smoothly along the axial direction to avoid circumferential displacement. This ensures that after the second arm 42 and the third arm 43 are completely separated from the interventional sheath 10, they can unfold in the blood vessel at their respective preset angles, ultimately achieving precise fixation of the filter 40.

[0044] However, in the existing technology, during the filter release and offset calibration process, the transmission of adjustment force (i.e., thrust and pull) relies on the contact friction generated by the radial resistance of the limiting member and the inner wall of the delivery sheath against the support structure (i.e., the first support arm, the second support arm, and the third support arm). During the filter release stage, the second and third support arms need to be deployed in the order of the second support arm first and the third support arm last. However, the radial resistance of the limiting member and the inner wall of the delivery sheath against the second and third support arms (relying only on friction to form a passive constraint, which cannot resist circumferential disturbances during movement) cannot lock the circumferential position of the second and third support arms. When the second and third support arms move in the delivery sheath along the first direction (retraction direction) or the second direction (release direction), the second support arm may be circumferentially offset to the preset path of the third support arm, causing the third support arm to contact and interfere before the second support arm is fully deployed, thereby interfering with the deployment posture of the filter and ultimately affecting the structural stability of the filter after precise positioning. Furthermore, in the existing technology, the second and third support arms lack circumferential guidance when retracting the filter. This may cause the second and third support arms to be tilted and retracted due to circumferential offset (for example, the barbs of the second support arm are circumferentially tilted towards the inner wall of the delivery sheath). As a result, when the second and third support arms retract, the barbs or anchors are likely to scrape the inner wall of the delivery sheath, or even rub against the blood vessel wall when passing through the distal opening of the delivery sheath. This not only increases the wear and tear on the device, but also increases the risk of damage to the vascular intima.

[0045] The present invention fixes the second arm 42 and the third arm 43 at a preset circumferential interval position by abutting the side wall 3111 of the slot 311 with the circumferential sides of the second limiting part 421 and the side wall 3111 of the slot 311 with the circumferential sides of the third limiting part 431. This ensures that the second arm 42 and the third arm 43 always move along their respective preset paths, avoids the second arm 42 and the third arm 43 from interfering with each other, and strictly follows the unfolding order of the second arm 42 first and the third arm 43 last in the blood vessel. This allows the filter 40 to be precisely positioned and form a stable umbrella-shaped structure, ensuring that the thrombus capture gap is uniform and thus stably performing the thrombus capture function. Furthermore, when retracting the filter 40, the side wall 3111 of the slot 311 abuts against the circumferential sides of the second limiting part 421, and the side wall 3111 of the slot 311 abuts against the circumferential sides of the third limiting part 431, which provides axial guidance for the second arm 42 and the third arm 43. This ensures that the second arm 42 and the third arm 43 always retract in a direction parallel to the axis Q of the interventional sheath 10, avoiding the barbs or anchors scraping the inner wall of the interventional sheath 10 or the blood vessel wall due to circumferential displacement. This reduces the risk of instrument wear and vascular damage during the retraction process, and achieves safe retraction and precise deployment of the filter 40.

[0046] It should be noted that, in this invention, preferably, the total number of the first arm 41, the second arm 42 and the third arm 43 are evenly distributed, and the circumferential interval between adjacent first arms 41, second arms 42 and third arms 43 is 30°.

[0047] It should be noted that the imaging equipment in this invention can be any medical imaging equipment that is routinely used in interventional surgery and is suitable for the positioning of intravascular instruments, such as X-ray digital subtraction angiography (DSA). This invention does not limit this type of equipment.

[0048] In some examples, the parameter Figure 5 As shown, the second limiting part 421 forms a first strip-shaped abutment surface 4211 extending axially on the side away from the groove 311, and the third limiting part 431 forms a second strip-shaped abutment surface 4311 extending axially on the side away from the groove 311. The first strip-shaped abutment surface 4211 and the second strip-shaped abutment surface 4311 form line contact with the inner wall 102 of the intervention sheath 10 through shape memory recovery force. By extending axially along the first strip-shaped contact surface 4211 and the second strip-shaped contact surface 4311, and in conjunction with the shape memory restoring force, a line contact is formed with the inner wall 102 of the interventional sheath 10. Compared with point contact, line contact can extend the contact length between the limiting part (i.e., the second limiting part 421 and the third limiting part 431) and the inner wall 102 of the interventional sheath 10, thereby improving the fit stability. Compared with surface contact, line contact can reduce the contact area between the limiting part and the inner wall 102 of the interventional sheath 10, and can maintain the friction force within an appropriate range that ensures the radial constraint of the inner wall 102 of the interventional sheath 10 on the second limiting part 421 and the third limiting part 431 without hindering movement. This avoids the movement jamming caused by excessive surface contact friction between the first support arm, the second support wall and the third support wall and the inner wall of the delivery sheath in the prior art. Furthermore, as the first strip-shaped contact surface 4211 and the second strip-shaped contact surface 4311 extend axially, during the movement of the filter 40 in the second or first direction, both the first strip-shaped contact surface 4211 and the second strip-shaped contact surface 4311 maintain continuous line contact with the inner wall 102 of the intervention sheath 10. This prevents the second limiting part 421 and the third limiting part 431 from having their contact interrupted when sliding within the slot 311, thus providing continuous radial constraint on the second limiting part 421 and the third limiting part 431 by the inner wall 102 of the intervention sheath 10.

[0049] In some examples, the parameter Figure 5As shown, the number of slots 311 is the sum of the number of the second support arm 42 and the third support arm 43. Each slot 311 accommodates only one second limiting part 421 or one third limiting part 431, and the circumferential spacing angle between adjacent slots 311 is equal. This ensures that the slots 311 can be matched one-to-one with the second limiting part 421 and the third limiting part 431, ensuring smooth sliding of each second limiting part 421 and the third limiting part 431 during axial movement within their respective slots 311. Simultaneously, each second limiting part 421 and the third limiting part 431 can form circumferential abutment with the side wall 3111 of its corresponding slot 311, achieving precise circumferential limiting fit. With adjacent slots 311 spaced evenly in the circumference, the second arm 42 and the third arm 43 are provided with fixed circumferential distribution positions. This constrains each of the second arm 42 and the third arm 43 to maintain a preset circumferential distribution angle during release and retraction adjustment, preventing circumferential displacement of the second arm 42 and the third arm 43. In addition, the limiting structure 31 can evenly transmit driving force to each of the second arm 42 and the third arm 43, avoiding tilting of the filter 40 due to uneven force. Ultimately, this ensures that after the filter 40 is released, the first arm 41, the second arm 42, and the third arm 43 can all unfold in the blood vessel at their respective preset angles, improving the thrombus capture efficiency of the filter 40 and its adaptation stability with the blood vessel wall.

[0050] In some examples, there are six slots 311. There are six first arms 41, three second arms 42, and three third arms 43. The twelve arms (six first arms 41, three second arms 42, and three third arms 43) are evenly distributed at 30° circumferential intervals. The second arms 42 and third arms 43 are arranged alternately, and adjacent second arms 42 and third arms 43 are separated by one first arm, forming a 60° circumferential interval. This corresponds to the six slots 311 being distributed at 60° intervals, achieving precise adaptation between the second limiting part 421, the third limiting part 431, and the slots 311.

[0051] In some examples, the parameter Figure 7As shown, the cross-section of the side groove wall 3111 of the slot 311 is an arc shape that protrudes or is recessed into the slot 311. The surfaces of the second limiting part 421 and the third limiting part 431 that abut against the side groove wall 3111 are both arc surfaces that fit the arc shape. The arc length formed between the two side groove walls 3111 of the slot 311 increases radially outward, and the slot 311 has a radially outward flared structure. The surfaces of the second limiting part 421 and the third limiting part 431 that abut against the side groove wall 3111 are both adapted arc surfaces, which can increase the contact area between the second limiting part 421 and the third limiting part 431 and the side groove wall 3111 respectively, so as to disperse the circumferential constraint force and effectively resist the circumferential torsion tendency of the filter 40 caused by blood flow impact or operation shaking during the release or retraction adjustment process. This ensures that the second arm 42 and the third arm 43 always maintain the preset circumferential interval, and ensures that after the filter 40 is released, the first arm 41, the second arm 42 and the third arm 43 can all be deployed in the blood vessel at their respective preset angles. As the filter 40 moves toward the distal opening 101 of the intervention sheath 10, and the second arm 42 and the third arm 43 gradually disengage from the radial constraint of the intervention sheath 10, their shape memory restoring force will cause the second limiting part 421 and the third limiting part 431 to expand radially outward. The slot 311 of the flared structure can provide sufficient radial disengagement space for the second limiting part 421 and the third limiting part 431, preventing the second arm 42 and the third arm 43 from being obstructed from unfolding due to the restriction of the side groove wall 3111, and ensuring that the second arm 42 and the third arm 43 can smoothly disengage from the slot 311 under the action of the shape memory restoring force.

[0052] In some examples, the parameter Figure 5 and Figure 6 As shown, the filter 40 includes a head end 44, and a first arm 41, a second arm 42, and a third arm 43 extending from the rear side of the head end 44 along a first direction; the first arm 41, the second arm 42, and the third arm 43 are evenly distributed circumferentially. The evenly distributed circumferential distribution of the first arm 41, the second arm 42, and the third arm 43 ensures that after the filter 40 is released, the first arm 41, the second arm 42, and the third arm 43 form a uniform circumferential support effect within the blood vessel. The contact pressure and supporting force between each of the first arm 41, the second arm 42, and the third arm 43 and the blood vessel wall are basically consistent, preventing the filter 40 from axially shifting or circumferentially twisting due to unilateral force imbalance, and ensuring that the filter 40 is stably fixed in the target position for a long time under the impact of blood flow. At the same time, it creates a uniform thrombus capture gap between each of the first arm 41, the second arm 42 and the third arm 43, reducing the capture blind zone, improving the thrombus interception efficiency, and avoiding excessive compression of the blood vessel wall by the local arms (first arm 41, second arm 42 or third arm 43), thus reducing the risk of damage to the vascular endothelium.

[0053] In some examples, the parameterFigures 1 to 3 As shown, the tip 44 engages with the distal opening 101 of the interventional sheath 10. By engaging the tip 44 with the distal opening 101 of the interventional sheath 10, the filter 40 is kept stable in the lumen of the interventional sheath 10 during delivery, preventing the filter 40 from dislodging from the lumen of the interventional sheath 10 before reaching the target position, thus avoiding erroneous release. During the movement of the control component 30 and the limiting structure 31 along the second direction, the first arm 41, the second arm 42, and the third arm 43 in the second direction are moved along the second direction within the lumen of the interventional sheath 10 by the pushing action of the limiting structure 31. This causes the head end 44, which is engaged with the orifice of the interventional sheath 10, to disengage from the lumen of the interventional sheath 10. As the filter 40 gradually moves to the target position, the multiple first arms 41, the second arms 42, and the third arms 43 disengage from the lumen of the interventional sheath 10 in sequence and switch from the retracted state to the deployed state in sequence. After the filter 40 is released at the target position, the multiple first arms 41, the second arms 42, and the third arms 43 deploy and form a stable umbrella-shaped structure to maintain the stability of the filter 40 in the blood vessel and effectively capture and prevent thrombi from entering the lungs.

[0054] In some examples, the parameter Figures 3 to 5 As shown, the tip 44 has a conical structure on the outside and forms a through guidewire lumen (not shown). The center of the tip 44 is hollowed out to form a hook-shaped structure. The tip 44 is constructed with a protrusion 441 that fits into the distal orifice of the interventional sheath 10. The conical structure on the outside of the tip 44 helps to smoothly guide the filter 40 through the blood vessel during delivery, thereby reducing resistance during the insertion of the interventional sheath 10. The guidewire lumen provides an insertion channel for the guidewire, allowing the guidewire to pass through the tip 44 and guide the filter 40 to move accurately to the target position, ensuring the precise positioning of the filter 40. The hook-shaped structure is used to retrieve the filter 40. The protrusion 441 allows the tip 44 to fit into the orifice of the interventional sheath 10, preventing accidental loosening of the filter 40 during delivery and ensuring that the filter 40 remains stably closed within the lumen of the interventional sheath 10.

[0055] In some examples, the limiting structure 31 is made of a medical-grade elastic material, such as medical-grade silicone. Medical-grade elastic materials have good biocompatibility, are non-irritating to human tissues, and avoid adverse reactions with vascular tissues and blood. It should be noted that the medical-grade elastic material selected for the limiting structure 31 must possess sufficient structural rigidity and appropriate elasticity. Sufficient structural rigidity is necessary to transmit axial tensile or thrust forces. When the control component 30 pushes along the second direction or pulls along the first direction, it prevents the limiting structure 31 from failing to transmit axial tensile or thrust forces due to excessive deformation (such as the collapse of the side wall 3111 of the slot 311). This requires ensuring circumferential contact between the slot 311 and the second limiting part 421 and the third limiting part 431, stably driving the filter 40 to move along the inner lumen of the interventional sheath 10. With appropriate elasticity, the limiting structure 31 can undergo controllable deformation when in contact with the first arm 41, the second limiting part 421, and the third limiting part 431. For example, when the filter 40 is in the retracted state, the radial holding force of the limiting structure 31 on the first arm 41 and the contact pressure with the second limiting part 421 and the third limiting part 431 form an appropriate frictional force to stabilize the retracted posture of the first arm 41, the second arm 42, and the third arm 43, and to avoid the first arm 41, the second arm 42, and the third arm 43 from sliding in the inner cavity of the intervention sheath 10 due to excessive friction. Meanwhile, the deformation recovery capability of the medical elastic material under stress ensures that the slot 311 can still restore its initial shape after sliding with the second limiting part 421 and the third limiting part 431 multiple times (e.g., during repeated calibration of offset), and continuously maintain the fitting gap and constraint performance with the second limiting part 421 and the third limiting part 431, avoiding the failure of circumferential limiting of the second limiting part 421 and the third limiting part 431 due to the plastic deformation of the material.

[0056] In some examples, the parameter Figures 1 to 3 As shown, the control assembly 30 includes: an inner sheath 32 that extends continuously into the lumens of the aspiration assembly 20 and the interventional sheath 10; a limiting structure 31 fitted onto the distal outer side of the inner sheath 32; and a handle 33 disposed at the end of the inner sheath 32 extending out of the aspiration assembly 20. The inner sheath 32 extends continuously into the lumens of the aspiration assembly 20 and the interventional sheath 10, and its lumen is aligned with and communicates with the guidewire lumen in the tip 44, providing an insertion channel for the guidewire. The handle 33 controls the movement of the inner sheath 32 and the limiting structure 31 within the lumen of the interventional sheath 10 to adjust the position of the filter 40 in real time. The inner sheath 32 also guides the filter 40, ensuring its stability during delivery and allowing it to be accurately and smoothly deployed to the target location in the inferior vena cava.

[0057] In some examples, the parameter Figure 2 and Figure 3As shown, the inner sheath 32 is radially recessed to form a connecting tube segment 321 with a limiting structure 31. The distal end of the connecting tube segment 321 is connected to the limiting structure 31. The outer diameter of the connecting tube segment 321 is smaller than the outer diameter of the inner sheath 32, so that the inner cavity of the intervention sheath 10 can accommodate the limiting structure 31 and the first arm 41, the second arm 42, and the third arm 43 in their retracted state. This reduces friction and resistance during the release of the filter 40, ensuring that the filter 40 can be released smoothly and gradually unfold.

[0058] In some examples, the parameter Figure 6 As shown, the first support arm 41 includes: a first support 411 and a second support 412 that extend continuously relative to the central axis P of the filter 40 in a direction away from the axis, and a third support 413 that connects the second support 412 and extends continuously relative to the central axis P of the filter 40 in a direction close to the axis; the connection between the second support 412 and the third support 413 has an arc transition.

[0059] The first branch 411 initially supports the first arm 41 during its deployment, providing initial external force support. The second branch 412 further expands to provide greater support. Together, the first and second branches support the first arm 41's deployment, with the second branch 412 distributing the support force during deployment. This allows the first arm 41 to apply uniform pressure to the blood vessel through its arc-shaped transition structure, ensuring that the filter 40 does not cause excessive local pressure on the blood vessel during deployment, thus preventing vascular damage. The third branch 413 extends inward to create a centripetal support force within the filter 40, balancing the outward support forces of the first and second branches 412. This prevents the first arm 41 from deforming due to excessive outward support during deployment, ensuring the overall rigidity and stability of the filter 40. Furthermore, when the filter 40 is in the retraction adjustment process (the first arm 41 is in the deployed state), the arc-shaped transition structure can reduce the contact friction area between the first arm 41 and the blood vessel wall, reduce the risk of blood vessel wall damage caused by relative sliding, and at the same time reduce the resistance during retraction, ensuring a smooth adjustment process.

[0060] In some examples, the parameter Figure 6As shown, the second arm 42 has an overall arc-shaped structure. The free end of the second arm 42 is equipped with a barb 422 that bends radially outward for anchoring on the blood vessel wall. The barb 422 is formed near the proximal end of the second limiting portion 421, and it abuts against the side wall 3111 of the slot 311 circumferentially. Because the second arm 42 has an arc-shaped overall profile, its arc-shaped structure easily adapts to the shape of the blood vessel when deployed, allowing for a uniform pressure distribution on the blood vessel wall at the point of contact, avoiding excessive local pressure and reducing the risk of blood vessel damage. Furthermore, the second arm 42 provides uniform support to the filter 40 when it is deployed, ensuring stable deployment at the target position and providing stable support for the subsequent release of the third arm 43. After the filter 40 is deployed, it is firmly in contact with the blood vessel wall by the barb 422, preventing the filter 40 from moving with the blood flow in the blood vessel and enabling the filter 40 to be stably kept in the target position.

[0061] During the release movement of the second arm 42 in the second direction, the barb 422 slides synchronously along the side groove wall 3111 with the second limiting part 421. This restricts the circumferential swing of the second arm 42, ensuring that the arc-shaped structure of the second arm 42 can unfold at a preset angle. This allows for uniform pressure distribution when in contact with the blood vessel wall, preventing excessive local pressure that could cause vascular damage. It also provides stable guidance for the axial movement of the second arm 42, ensuring its smooth release. During the retraction adjustment of the filter 40, when the barb 422 retracts with the second arm 42, the circumferential contact between the barb 422 and the side groove wall 3111 guides the barb 422 to smoothly retract axially, preventing it from scraping against the side groove wall 3111 due to circumferential displacement. Furthermore, when the filter 40 is in the retracted state, the circumferential contact between the barb 422 and the side groove wall 3111 can also restrain the second arm 42 from excessive radial expansion, preventing the barb 422 from prematurely contacting the inner wall 102 of the intervention sheath 10 to generate additional friction or scratch the inner wall 102 of the intervention sheath 10, thus ensuring the stability and smooth delivery of the filter 40 in the overall retracted state.

[0062] In some examples, the parameter Figure 6As shown, the overall outline of the third arm 43 is a straight-line structure. The free end of the third arm 43 extends along the first direction to form an anchor 432 for anchoring on the blood vessel wall. The anchor 432 is formed at the proximal end of the third limiting portion 431, and the anchor 432 forms an abutment fit with the side groove wall 3111 of the slot 311 in the circumferential direction. The straight-line structure of the third arm 43 helps to provide more stable linear support for the filter 40 in the blood vessel, so that the filter 40 can provide solid support when deployed. Furthermore, the third arm 43 can be deployed quickly and stably, avoiding excessive disturbance to the filter 40, keeping the filter 40 in the target position, and ensuring the stability of the filter 40 structure. The anchor 432 has the function of penetrating the blood vessel wall, ensuring that the filter 40 can be firmly anchored on the blood vessel wall, preventing the filter 40 from shifting or falling off under the action of blood flow.

[0063] During the release movement of the third arm 43 in the second direction, the anchor 432 slides synchronously along the side groove wall 3111 with the third limiting part 431, which can limit the circumferential swing of the third arm 43 and ensure that the linear structure of the third arm 43 can unfold at a preset angle to provide solid linear support for the filter 40, enhance the overall structural stability of the filter 40, and also provide stable guidance for the third arm 43 during axial movement, ensuring that the third arm 43 is released smoothly. During the retraction adjustment of the filter 40, when the anchor 432 retracts with the third arm 43, the circumferential contact between the anchor 432 and the side groove wall 3111 can guide the anchor 432 to retract smoothly along the axial direction, so as to avoid scraping the side groove wall 3111 due to circumferential displacement.

[0064] In some examples, the parameter Figure 6 As shown, the first branch 411 extends at a greater angle away from the central axis of the filter 40 than the second branch 42 extends at a greater angle away from the central axis of the filter 40. The larger angle of the first branch 411 provides stronger initial support during the deployment of the filter 40, facilitating its rapid adaptation to the intravascular space and ensuring sufficient support during initial deployment so that the filter 40 can be stably positioned at the target location within the blood vessel.

[0065] In some examples, the parameter Figures 1 to 3As shown, the aspiration assembly 20 includes a multi-channel valve tube 21 and an aspiration tube 22. The multi-channel valve tube 21 has a side tube 211 configured to communicate with the aspiration tube 22, and a seal (not shown) disposed at the proximal end of the multi-channel valve tube 21. An inner sheath 32 extends through the multi-channel valve tube 21 along a second direction and reaches the interventional sheath 10. The seal is used to seal the connection between the inner sheath 32 and the proximal end of the multi-channel valve tube 21. A vacuum device (not shown) is externally connected to the aspiration tube 22, enabling it to aspirate and evacuate air from the multi-channel valve tube 21 and the interventional sheath 10, clearing air or impurities from inside the vena cava filter delivery system 100, ensuring smooth delivery of the filter 40. The seal, disposed at the proximal end of the multi-channel valve tube 21, seals the connection between the inner sheath 32 and the multi-channel valve tube 21 to prevent leakage of blood, liquid, or gas, maintaining the airtightness of the aspiration assembly 20 and preventing risks caused by gas or blood leakage. In some examples, the seal may be configured as a sealing nut to lock the position of the inner sheath 32 and maintain the seal of the extraction assembly 20. During the delivery of the filter 40 through the inner sheath 32, the sealing nut may be loosened appropriately, allowing the inner sheath 32 to move relative to the intervention sheath 10 to adjust the release position of the filter 40.

[0066] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A limiting structure for an umbrella-shaped vena cava filter, characterized in that, This is applied to a vena cava filter delivery system, the vena cava filter delivery system comprising: An interventional sheath containing a filter within its lumen; An air extraction assembly is disposed at the proximal end of the interventional sheath; A control component extends axially continuously into the inner cavity of the suction component and the intervention sheath and connects to the filter to drive the filter to move bidirectionally along the axial direction. The limiting structure is fixed to the far end of the control component and connected to the filter; The filter is constructed with a plurality of first arms, a plurality of second arms and a plurality of third arms distributed circumferentially, wherein the axial lengths of the first arms, the second arms and the third arms increase sequentially along a first direction (X1). The filter is disposed in the inner cavity of the interventional sheath in a retracted state. The limiting structure forms a plurality of axially extending slots along the circumferential direction. The second arm and the third arm respectively form a second limiting part and a third limiting part extending into the slots along the first direction (X1). The second limiting part and the third limiting part abut against the side wall of the slot on both sides along the circumferential direction and form a circumferential limiting fit with the slot. The second limiting part and the third limiting part abut against the inner wall of the intervention sheath through their shape memory restoring force. Both the second limiting part and the third limiting part have radial gaps (J1, J2) with the bottom wall of the groove.

2. The limiting structure of the umbrella-shaped vena cava filter according to claim 1, characterized in that, The second limiting part forms a first strip-shaped abutment surface extending axially on the side away from the slot, and the third limiting part forms a second strip-shaped abutment surface extending axially on the side away from the slot. The first strip-shaped abutment surface and the second strip-shaped abutment surface are in line contact with the inner wall of the intervention sheath through the shape memory restoring force.

3. The limiting structure of the umbrella-shaped vena cava filter according to claim 1, characterized in that, The number of slots is the sum of the number of the second arm and the third arm. Each slot can accommodate only one second limiting part or one third limiting part, and the circumferential spacing angle between adjacent slots is equal.

4. The limiting structure of the umbrella-shaped vena cava filter according to claim 1, characterized in that, The cross-section of the side groove wall of the slot is an arc shape that protrudes or is recessed into the slot, and the surfaces of the second and third limiting parts that abut against the side groove wall are both arc surfaces adapted to the arc shape.

5. The limiting structure of the umbrella-shaped vena cava filter according to claim 1, characterized in that, The limiting structure is made of medical elastic material.

6. The limiting structure of the umbrella-shaped vena cava filter according to claim 1, characterized in that, The filter includes a head end, and a first arm, a second arm and a third arm extend from the rear side of the head end along the first direction. The first arm, the second arm, and the third arm are distributed at equal intervals along the circumference.

7. The limiting structure of the umbrella-shaped vena cava filter according to claim 6, characterized in that, The first support arm includes: a first branch and a second branch that extend continuously in a direction away from the central axis of the filter, and a third branch that connects the second branch and extends continuously in a direction close to the central axis (P) of the filter. The connection between the second branch and the third branch has an arc-shaped transition.

8. The limiting structure of the umbrella-shaped venous filter according to claim 7, characterized in that, The second arm has an overall arc-shaped structure, and the free end of the second arm is provided with barbs that bend radially outward for anchoring on the blood vessel wall, and the barbs are formed at the proximal end of the second limiting portion.

9. The limiting structure of the umbrella-shaped vena cava filter according to claim 1, characterized in that, The overall outline of the third arm is a straight structure, and the free end of the third arm extends along the first direction to form an anchor for anchoring on the blood vessel wall. The anchor is formed at the proximal end of the third limiting portion.

10. The limiting structure of the umbrella-shaped venous filter according to claim 8, characterized in that, The first branch extends at an angle greater than the angle of the second arm extending ...

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