CN115944356A

CN115944356A - Bracket component for removing thrombus

Info

Publication number: CN115944356A
Application number: CN202310094522.1A
Authority: CN
Inventors: 杨文广; 王可鹏; 王玉强
Original assignee: Shanghai Hengchang Medical Technology Co ltd
Current assignee: Shanghai Hengchang Medical Technology Co ltd
Priority date: 2023-02-10
Filing date: 2023-02-10
Publication date: 2023-04-11
Also published as: WO2024164536A1

Abstract

The invention discloses a stent assembly for removing thrombus, comprising: a deformable scaffold network comprising a proximal scaffold network and a distal scaffold network. The proximal stent mesh comprises a plurality of proximal stent struts, the proximal stent struts are bent rods, and the proximal stent struts comprise a proximal constricting portion and a proximal expanding portion. The distal end stent mesh comprises a plurality of distal end stent rods, the distal end stent rods are straight rods, and the distal end stent rods comprise a distal end constricting part and a distal end expanding part. The proximal and distal dilators are interconnected such that the proximal and distal stent rods are connected to form a cage-like structure. The near end of the bracket component has the characteristics of good thrombus scraping effect, large opening and good supporting performance. The inner space of the bracket is large, and the bracket is well jointed with the inside of the blood vessel of a patient. The efficiency for removing old thrombus with larger volume and stronger adherence is higher and more thorough. The expansion state of the bracket component can be adjusted by matching the handle with the DSA image, and the applicable diameter range of the blood vessel is larger.

Description

Bracket component for removing thrombus

Technical Field

The present invention relates to a medical device, more specifically, to a stent assembly device for eliminating thrombus for treating acute or subacute pulmonary embolism.

Background

Thrombus formation is caused by an imbalance in the coagulation regulation mechanism in vivo due to various factors, including damage to vascular endothelial cells, abnormal blood flow conditions, and increased blood coagulability. The venous thrombus is mainly attached to a blood vessel wall in a venous blood vessel, is a hard thrombus with high fibrinogen content, and gradually changes from a soft thrombus into a hard embolus with high adhesion degree with the blood vessel wall along with the time of the thrombus. Thrombus caused by pulmonary embolism generally has the characteristic of larger volume, and is blocked at the positions of the main pulmonary artery, the left and right main pulmonary arteries and the branch arteries or branch arteries of the left and right pulmonary branches.

The existing surgical instruments are mainly embolectomy support devices designed aiming at fresher emboli under the acute pulmonary embolism state, and are mainly integrally woven cage-shaped, barrel-shaped, disc-shaped or disc-shaped supports, and the number of cages, barrels, discs or discs of the supports can be 1 to 3 or more. The thrombus removal device has good application effect in the field of arterial thrombus removal, but has no remarkable effect on the subacute thrombus with long formation time. Although the commonly used braided stent can prevent thrombus from escaping, the commonly used braided stent does not have ideal acquiring effect on old thrombus which is hard, large in volume and strong in adherence. In addition, aspiration of thrombi with such features is also difficult to capture and aspirate outside the patient, and the catheter is often blocked by the thrombus volume during aspiration.

Most pulmonary embolisms are subacute thromboembolic disorders. Acute embolisms can be completely treated by means of thrombolysis, or embolisms can be removed by means of auxiliary thrombectomy. However, most of the sub-acute thromboembolic patients do not have satisfactory therapeutic effects on thrombolysis or auxiliary suction, and the auxiliary suction effect of the new woven stent thrombus removal or thrombus crushing device is not obvious.

In summary, in the current acute or subacute pulmonary embolism, the thrombus extraction device for aspiration thrombus extraction cannot remove thrombus, or thrombolytic can not remove thrombus instantly, has a very limited thrombus extraction effect due to structural defects, and cannot completely remove thrombus or cannot remove thrombus at all by the existing thrombus extraction device.

Disclosure of Invention

Aiming at the problems of the prior art for treating acute or subacute pulmonary embolism, the invention provides the stent component for removing thrombus, which has large proximal opening and good support performance. The invention at least solves the problems of low efficiency of taking out the heavy-load thrombus, incomplete clearing, poor fitting property of the bracket component and the interior of the blood vessel of a patient, inflexible operation of the bracket component in the operation, small range of applicable blood vessels and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

a stent assembly for removing thrombus, comprising: a deformable stent mesh comprising a proximal stent mesh and a distal stent mesh; the near-end stent mesh comprises a plurality of near-end stent rods, the near-end stent rods are bending rods, and the near-end stent rods comprise a near-end constricting part and a near-end expanding part; the far-end support net comprises a plurality of far-end support rods, the far-end support rods are straight rods, and the far-end support rods comprise far-end contracting parts and far-end expanding parts; the proximal and distal stent struts are interconnected such that the proximal and distal stent struts are connected to form a cage-like structure.

As one embodiment of the present invention, the bending beam includes a plurality of curved arcs to form a continuous curved shape.

As an embodiment of the present invention, the width of the bending bars at both ends is greater than the width at the middle.

As an embodiment of the invention, the deformable stent web comprises a stretched state and an expanded state in which the proximal stent rods maintain a bent rod configuration.

As an embodiment of the present invention, the number of the distal stent rods is greater than the number of the proximal stent rods, so that the mesh density of the distal stent mesh is greater than that of the proximal stent mesh.

As an embodiment of the present invention, the mesh size of the proximal stent mesh is larger than the mesh size of the distal stent mesh.

As an embodiment of the present invention, the proximal stent mesh comprises a proximal restraint rod and three proximal stent rods, each proximal stent rod further comprises two primary proximal bifurcations, each primary proximal bifurcation further comprises two secondary proximal bifurcations; the proximal end restriction rod and the three proximal end support rods form a proximal end restriction part, and the primary proximal end bifurcation and the secondary proximal end bifurcation form a proximal end expansion part.

As another embodiment of the present invention, the proximal stent mesh comprises a proximal constricting rod and six proximal stent rods, each proximal stent rod further comprising two primary proximal bifurcations; the proximal end restriction rod and the six proximal end support rods form a proximal end restriction part, and the first-stage proximal end bifurcation forms a proximal end expansion part.

In one embodiment of the invention, the primary proximal bifurcation is connected to the secondary proximal bifurcation, which is connected to the distal dilating portion.

As one embodiment of the invention, the primary proximal bifurcation is directly connected to the distal dilating portion.

As an embodiment of the invention, the proximal and distal constrictions are each connected to a pusher rod of an embolectomy device for removing thrombi.

In the technical scheme, the near end of the bracket component has the characteristics of good thrombus scraping effect, large opening and good supporting performance, and the bracket component has large internal space and better fit with the inside of a blood vessel of a patient. The efficiency for removing hard old thrombus with larger volume and stronger adherence is higher, and simultaneously, the old thrombus is more thorough. Meanwhile, the expansion state of the bracket component can be adjusted by matching a handle with a DSA (Digital subtraction angiography) image, and the bracket component can be flexibly suitable for carrying out embolectomy with a wider range of vessel diameters.

Drawings

FIG. 1 is a schematic view of a stent assembly;

FIG. 2 is a schematic view of a three-port stent structure;

FIG. 3 is a schematic view of a mesh structure at the proximal end of a three-port stent;

FIG. 4 is a schematic view of a proximal end opening of a three-opening stent;

FIG. 5 is a schematic view of a mesh structure of a bent rod at the proximal end of a stent;

FIG. 6 is a schematic view of a six-port stent configuration;

FIG. 7 is a schematic view of a six-port stent proximal mesh structure;

FIG. 8 is a schematic view of a six-port stent with proximal port openings;

FIG. 9 is a schematic view of a distal cutting dense web structure;

FIG. 10 is a schematic view of a two-stage curved arc cut;

FIG. 11 is a schematic illustration of stent embolectomy;

FIG. 12 is a schematic view of a bending beam.

In the figure: 1-deformable support net, 2-guide head, 3-inner push rod, 4-outer push rod, 5-developing ring and 6-conveying pipe;

101-proximal restraint bar, 102-proximal stent bar, 114-primary proximal bifurcation, 103-secondary proximal bifurcation, 104-first distal stent bar, 105-second distal stent bar, 106-third distal stent bar, 107-distal restraint bar;

109-first proximal mesh, 117-second proximal mesh, 110-third proximal mesh, 111-first distal mesh, 112-second distal mesh, 113-third distal mesh, 115-proximal stent mesh, 116-distal stent mesh;

123-first proximal arc, 124-second proximal arc, 125-third proximal arc, 126-fourth proximal arc. BV-blood vessel, PEA-thrombus mass, PEB-target thrombus;

127. 128, 129, 130, 131, 132-bent rod portion, 133-wall thickness, 134-rod width.

Detailed Description

The technical solution in the embodiments of the present invention will be further clearly and completely described below with reference to the accompanying drawings and embodiments. It is obvious that the described embodiments are used for explaining the technical solution of the present invention, and do not mean that all embodiments of the present invention have been exhaustively exhausted.

Examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

It should be understood that "mounted," "connected," and "coupled" are to be construed broadly and may include, for example, fixed connections, detachable connections, or a combination thereof; it may be a mechanical connection or an electrical connection; it can be connected directly, indirectly through an intermediate medium, or internally between the two components. However, if other words have the same purpose, they may be replaced with other expressions.

As used in this specification and the appended claims, the terms "a", "an", and/or "the" do not denote a particular singular form, but rather include plural forms, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" are intended to be inclusive and mean that there may be additional steps or elements other than the expressly identified steps or elements.

In relation to the present description the terms "distal/distal" and "proximal/proximal", wherein proximal/proximal refers to the end closer to the operator and distal/distal refers to the end further away from the operator, or into a blood vessel of the human body.

Referring to fig. 1-11, a stent assembly for thrombus removal is disclosed. The stent assembly, i.e., the deformable stent mesh 1, is installed in a thrombectomy stent system of a thrombus treatment device. The thrombectomy support system mainly comprises a deformable support net 1, a guide head 2, an inner push rod 3, an outer push rod 4, a developing ring 5 and the like, and is integrally installed in a delivery pipe 6 and can move relatively along the delivery pipe 6, so that the support system can extend out of/retract back from the delivery pipe 6. In the stent system, the proximal end of the inner push rod 3 is connected to the operating handle, and the distal end is connected to the distal end constriction rod 107 of the transformable stent mesh 1. The proximal end of the outer pushing rod 4 is connected with the operating handle, and the distal end is connected with the proximal end retracting rod 101 of the deformable support net 1. The size of the cage-like lattice structure of the transformable stent mesh 1 is varied by the axial relative movement of the inner and outer push rods to form a unitary structure that moves between a stretched state and an expanded state.

Referring to fig. 2, the transformable stent-graft 1 is composed of a proximal stent-graft 115 and a distal stent-graft 116, which are formed as a unitary structure movable between a stretched state and an expanded state by a plurality of interconnected struts, the proximal stent-graft 115 comprising a proximal constricting rod 101 and a plurality of proximal stent-grafts 102 connected to an outer pushing rod 4. The invention can realize the deformable support net 1 with different effects through different numbers of the proximal support rods 102, and the number of the proximal support rods 102 is not limited.

As a first embodiment of the present invention, as shown in fig. 2 to 5, the proximal stent mesh 115 includes a proximal narrowing bar 101 connected to the outer push bar 4 and three proximal stent bars 102. The proximal harvesting rod 101 may be considered as an extension of the proximal support rod 102 or as a separate rod. As an embodiment of the proximal restraining bar, the proximal restraining bar forms a surrounding portion surrounding the outer pushing bar 4 at the proximal end position of the deformable support net 1, and the surrounding portion can be regarded as a branch formed by each proximal support bar 102 at the proximal end position, and two adjacent branches are connected two by two to form a ring shape, as shown in fig. 3.

In the present embodiment, i.e., in the case where the number of the proximal stent rods 102 is 3, the proximal constricting rods 101 and the three proximal stent rods 102 constitute a proximal constricting portion. The proximal end bundling rod 101 fixes one end of the deformable support net 1 in the thrombus removal support system by connecting with the distal end of the outer push rod 4, and the connection mode can be a pebax material hot melting mode or a glue bonding mode. Each proximal stent strut 102 further comprises two primary proximal bifurcations 114, and each primary proximal bifurcation 114 further comprises two secondary proximal bifurcations 103. It can be seen that in the case of 3 proximal stent struts 102, the transformable stent web 1 forms a two-stage proximal bifurcation structure, one-stage proximal bifurcation 114 and one-stage proximal bifurcation 103. The primary proximal bifurcation 114 and the secondary proximal bifurcation 103 constitute a proximal dilating portion. The proximal flare and the proximal constriction are opposite concepts, both of which are located in the proximal half of the stent mesh 1, and the proximal constriction is formed into a constricted shape to connect the outer pusher 4, while the proximal flare may be expanded relative to the proximal constriction to form a cage-like structure.

An important feature of the present invention is that the primary proximal bifurcation 114 and the secondary proximal bifurcation 103 of the proximal stent struts 102 are both bending struts, which are bent under tension and expansion. The bending rod is in the form that the two end rods are wide and thick, and the middle rod is wide and thin, namely the width of the two ends of the bending rod is larger than that of the middle part, and the design is convenient for the bracket to be put into the sheath tube. The distal end of the secondary proximal bifurcation 103 is connected to a distal dilating portion. As shown in FIG. 12,

bend beam portions

127, 129, 130 and 132 are wide-ended beams, as compared to bend

beam portions

128 and 131 which are thin, intermediate beams. The two ends and the middle of the bending bar are relative concepts and are not limited to only the two ends or the middle of one bar.

With continued reference to fig. 2-5, the distal stent mesh 116 includes a first distal stent rod 104, a second distal stent rod 105, a third distal stent rod 106, and a distal harvesting rod 107 connected to the secondary proximal bifurcation 103. The first distal stent rod 104 and the second distal stent rod 105 constitute a distal expansion portion. The third distal support rod 106 and the distal binding rod 107 constitute a distal binding portion. The distal expansion and the distal constriction are relative concepts, both being located in the distal half of the stent mesh 1, and the distal constriction is shaped to constrict to connect the inner push rod 3, while the distal expansion can be expanded relative to the distal constriction to form a cage-like structure.

Unlike the proximal stent mesh 115, each rod in the distal stent mesh 116 is a straight rod. The far-end beam-collecting rod 107 is connected with the far ends of the guide head 2 and the inner push rod 3 to fix the other end of the deformable support net 1 in the embolectomy support system, and the connection mode can adopt pebax material hot melting and can also adopt a glue bonding mode. Referring to fig. 9, the distal stent mesh 116 is in a dense mesh shape, and the expanded shape is in a shape in which the mesh area gradually decreases from the top of the expanded stent to the distal end. Comparing fig. 4 and fig. 9, it can be seen that the pore diameters of the distal end grids are smaller than those of the proximal end grids, and the design enables the captured thrombus to be firmly enclosed in the stent, so as to prevent the thrombus from escaping. The proximal stent mesh 115 and the distal stent mesh 116 are interconnected at the central vertical line position shown in fig. 2, and the vertical line is merely used as a mark for roughly dividing the proximal stent mesh 115 and the distal stent mesh 116, and does not have a separate entity, nor does it indicate a specific ratio of the proximal stent mesh 115 and the distal stent mesh 116.

With continued reference to fig. 2, the rods of the transformable stent mesh 1 form a mesh structure that is in the shape of a shuttle or oval. From the viewpoint of the overall structure, the number of the distal stent struts is larger than that of the proximal stent struts, so that the mesh density of the distal stent mesh 116 is larger than that of the proximal stent mesh 115, and the mesh size of the proximal stent mesh 115 is larger than that of the distal stent mesh 116. The near-end stent mesh 115 and the far-end stent mesh 116 are connected through I-shaped nodes to form a cage-shaped grid structure, and the connecting nodes are the highest points of the outline of the deformable stent mesh 1.

Referring to fig. 3, 4 and 5, in the present embodiment, i.e., in the case where the number of the proximal stent struts 102 is 3, the first proximal mesh 109 is formed by the proximal stent struts 102, the primary proximal bifurcation 114, the secondary proximal bifurcation 103 and the first distal stent strut 104. 3 to 6 first near-end meshes 109 are provided, so that the catching and acquisition of the large-load thrombus can be effectively realized. The proximal support rod 102 is thicker, the rod width is 0.15 to 0.5mm, and the wall thickness of the support is 0.15 to 0.5mm, so that larger proximal support rigidity can be provided, the rigid support of a large opening in the thrombus capture process is improved, and the thrombus extraction efficiency is higher. The number of the rods of the proximal support rod 102 is small, and the rods are longer relative to the distal support rods (the first distal support rod 104 and the second distal support rod 105), so that the compliance of the expanded deformable support net 1 when being contracted into the delivery pipe 6 can be improved, if the release position of the deformable support net 1 is not proper in the operation, the deformable support net 1 can be withdrawn into the delivery pipe 2, and the deformable support net 1 can be released again after the release position of the deformable support net 1 is adjusted by the support system, so that the deformable support net 1 can be recycled.

Referring to fig. 4, in the present invention, the strut width refers to the width of the struts (e.g., proximal constraining struts, proximal stent struts, distal constraining struts, etc.) distributed along the outer surface of the stent after cutting, and the stent wall thickness refers to the thickness from the inner surface of the stent to the outer surface of the stent, as shown by the stent wall thickness 133 and the strut width 134 in fig. 4. In the present invention, the width of the rod (e.g., proximal constricting rod, proximal stent rod, distal constricting rod, etc.) is understood to be the diameter of the cross-section of the rod, with larger rod widths resulting in larger cross-sectional diameters. In addition, since the stent is composed of a plurality of rods (e.g., a proximal constraining rod, a proximal stent rod, a distal constraining rod, etc.), the thickness from the inner surface of the stent to the outer surface of the stent is the thickness from the inner surface of the rod to the outer surface of the rod, and the difference in the wall thickness of the stent can also be understood as the difference in the cross-sectional area of the rods, and the cross-sectional area of the rods is large due to the wall thickness of the stent. It will be appreciated by those skilled in the art that the wall thickness of the same stent is variable, as the stent may be composed of a plurality of rods of different thicknesses.

Referring to fig. 2, 3 and 4, a second proximal mesh 117 is formed by the primary proximal bifurcation 114, the secondary proximal bifurcation 103 and the first distal stent rod 104. The secondary proximal bifurcation 103 and the first distal stent struts 104 form a third proximal mesh 110. The number of the second-stage proximal branches 103 and the first distal stent rod 104 is 12 to 24, the rod width is 0.15 to 0.5mm, and the wall thickness is 0.15 to 0.5mm, so that the stent net has high radial support force, can provide better adherence between the deformable stent net 1 and a patient blood vessel in the thrombus extraction process, and is beneficial to stripping more adherence emboli along the blood vessel wall, and therefore the stent net can provide thrombus extraction capability which cannot be obtained by other thrombus extraction methods. The primary proximal bifurcation 114 and the secondary proximal bifurcation 103 of the transformable stent mesh 1 are designed as S-shaped bent rods, and the primary proximal bifurcation 114 and the secondary proximal bifurcation 103 maintain a bent shape in a stretched state and an expanded state. Under this kind of state of buckling, the area of contact that the support scraped the thrombus in the intravascular axial is bigger than conventional straight-bar, and the effect of scraping the thrombus is just better. The third proximal mesh 110 and the second proximal mesh 117 form a supporting closed grid of the proximal large open grid, assisting the first proximal mesh 109 to function together as a thrombus capture.

Referring to fig. 6, 7 and 8, as a second embodiment of the present invention, the proximal stent net 115 may have a six-open configuration as shown in this example in addition to the three-open configuration described above, i.e., the proximal stent net 115 includes proximal narrowing bars 101 and 6 proximal stent bars 102 connected to the outer push bars 4.

In the present embodiment, i.e., in the case of 6 proximal stent struts 102, each proximal stent strut 102 further comprises twelve primary proximal bifurcations 114. It can be seen that in the case of 6 proximal stent struts 102, the stent mesh 1 is formed with only one proximal bifurcation, i.e., one proximal bifurcation 114 as shown in fig. 7. The proximal constricting rod 101 and the 6 proximal stent rods 102 constitute a proximal constricting portion. Twelve primary proximal bifurcations 114 constitute proximal dilating portions. The concepts of the proximal dilating portion and the proximal constricting portion are the same as those of the first embodiment of the present invention and will not be described herein.

Referring to fig. 8,6 of the proximal stent struts 102, two of them are grouped into three groups with an included angle of about 120 ° and are radially and uniformly distributed. The two proximal stent struts 102 of each set are outwardly bent in an arc envelope shape to form a fusiform first proximal mesh 109 with the first-stage proximal bifurcation 114 and the first distal stent strut 104. The first proximal mesh openings 109 formed between each set of proximal stent struts are diamond shaped and have a slightly smaller area than the fusiform mesh openings. The proximal stent strut 102 and the primary proximal bifurcation 114 are designed as bent struts that assume a bent state in both tension and expansion.

Comparing fig. 4 and 8, it can be seen that the three-port proximal stent is more uniform and larger than the six-port stent, so that the volume of thrombus that can pass through is larger than the six-port stent. Such a large opening design is more suitable for older, difficult to cut, large volumes of emboli. The number of rods of the three-opening proximal-end support is small and long, the support net is favorable for good sheath-entering compliance, the support net is more convenient to recycle repeatedly, operation failure caused by improper support release positions in the operation process is avoided, the support is recycled in time into the sheath tube, the support release positions are readjusted, and the effectiveness of thrombus extraction and the operation success rate are improved. On the other hand, the support rods of the six-opening stent are twice as many as the three openings, so that the support force and the support strength of the rod part are stronger, and the adherence of the stent to the blood vessel of the patient is better. It will be understood by those skilled in the art that the proximal stent net 115 with different radial supporting effects can be obtained by adjusting the specific number and connection relationship of the proximal stent struts 102, the primary proximal bifurcation 114 and the secondary proximal bifurcation 103, and these different combinations and their choices are all within the scope of the present invention.

Referring to fig. 2, 6 and 9, the first distal stent rod 104 and the second distal stent rod 105 constitute a first distal mesh 111. The second distal stent rod 105 and the third distal stent rod 106 constitute a second distal mesh 112. The third distal stent struts 106 and the distal constricting rods 107 form a third distal mesh 113. The first far-end mesh openings 111, the second far-end mesh openings 112 and the third far-end mesh openings 113 are all in a dense mesh grid shape, and the expanded shape of the stent is in a shape that the mesh area gradually becomes smaller from the top to the far ends. The pore diameter of the far-end grid is smaller than that of the near-end grid, so that the grabbed thrombus can be firmly enclosed in the stent, and the thrombus is prevented from escaping.

In general, the main function of the proximal stent mesh 115 of the deformable stent mesh 1 is to provide better radial support in the blood vessel of the patient in the expanded state, so that the proximal stent struts have thicker struts, which can provide higher support strength and provide larger radial support force. In addition, the larger opening formed by the proximal rod also plays a better supporting effect due to the larger strength of the proximal rod, because the increase of the number of the proximal bracket rods is not beneficial to the improvement of the radial strength, and the radial strength can be weakened. In addition, the main function of the distal stent web 116 of the transformable stent web 1 is to effectively capture the thrombus and prevent it from escaping, so that the distal stent rod adopts a thinner and denser structure than the proximal stent rod, thereby enabling a dense mesh structure to be formed, and the hemispherical mesh structure can better accommodate the thrombus in the distal stent web and prevent the thrombus from escaping.

As an embodiment of the present invention, the first distal stent rod 104 may have a visualization structure fixed thereon, which is disposed at the highest point of the first distal stent rod 104 after the stent mesh is expanded, and the visualization structure is disposed at this point to facilitate observation and judgment of the operator in the operation. The developing structure can also be arranged at other positions of the near-end support rod (primary near-end bifurcation and secondary near-end bifurcation) and/or the far-end support rod, so that the technical purpose of the invention can be realized, and the technical effect of the invention can be achieved. The fixing mode of the developing structure can be but is not limited to glue bonding or laser welding. The developing structure can enable the deformable support net 1 to have a developing effect under DSA (Digital subtraction angiography), and an operator can monitor the overall contour size of the deformable support net 1 in blood vessels in real time in the operation, so that the developing structure is an important reference in the operation.

Further, in the deformable stent mesh 1, the DSA developing structure may be a bent structure, an anchored hole structure, an i-beam structure, or a whole body developing structure. The key point of the invention is that the pulmonary embolism extraction stent with a whole body development structure is designed into a wide and thick stent, so that the overall stent has better development effect under DSA, or other development structure forms with the same effect can achieve the technical purpose of the invention, thereby achieving the technical effect of the invention, but the invention is not limited by the invention.

The deformable support 1 may be made entirely of a shape memory material, such as nitinol, or the like. The proximal stent mesh 115 and the distal stent mesh 116 are made of the same material. Referring to fig. 10, in some examples, a preliminary profile of a stent may first be cut by a laser cutting machine through a nickel titanium tube. Fig. 10 shows the deformable stent mesh 1 in a stretched state in which the proximal stent struts 102 are bent. Fig. 2, 6 and 11 show the expanded state of the transformable stent mesh 1 in which the proximal stent struts 102 also remain in a bent state.

The profile of the proximal support rod 102 may be, but is not limited to, two curved arcs. In other embodiments, the shape of the profile may be composed of three curved arcs or a plurality of curved arcs according to different manufacturing processes or design requirements, and these different combinations and choices are within the scope of the present invention. The two ends of the bending rod are wide and thick, the middle rod is wide and thin, namely the width of the two ends of the bending rod is larger than that of the middle of the bending rod, so that the support can be conveniently put into the sheath tube. Taking the design of two curved arcs shown in fig. 10 as an example, in order to ensure the bending shape of the rod portion after the deformable stent mesh 1 is heat-set, and to allow the bending rod to have a sufficient length and area for cutting thrombus in the axial direction, the first proximal arc 123 and the third proximal arc 125 are far away from the strut, the second proximal arc 124 and the fourth proximal arc 126 are close to each other, these two shapes are always kept to alternate along the axial direction, and the bending rod as a whole is in an S-shaped or continuous curved shape.

The profile of the cut stent web is further shaped by heat setting, so that the deformable stent web 1 has the above-mentioned structural characteristics. The heat setting process can impart the shape memory material into a desired shape, such as bent rods in the proximal stent mesh 115 in fig. 10 or straight rods in the distal stent mesh 116 in fig. 9, and the like. The larger the bending degree of the bending rod after heat setting is, the better the thrombus is axially removed, and the bending degree is closely related to the bending arc shape of the cutting contour. The greater the angle of opening of the first proximal arc segment 123 and the third proximal arc segment 125, the greater the curvature of the bending beam and the greater the degree of bending. The degree of bending is directly proportional to the opening angle of the proximal segments, as are the second and fourth

proximal segments

124, 126 connected to the first and third

proximal segments

123, 125, the greater the closing angle of each proximal segment, the greater the curvature of the bending rod, and likewise, the greater the degree of bending.

In addition to the effect of the bending angle of the bending rod on the degree of bending, the degree of bending of the proximal stent rod 102 and its primary proximal bifurcation 114 and secondary proximal bifurcation 103 is also related to the position of the respective arc segments. The proximal arc segments are alternately present on the rod, with the entire rod being in an S-shaped or continuously curved shape. The S-shaped or continuously curved shape is designed to maximize the bending of the support rods, thereby effectively increasing the area of the bending rods. The contact area that the support scraped the thrombus in the intravascular axial direction just is bigger than conventional straight-bar like this, and the effect of scraping the thrombus then can corresponding promotion. In addition, each arc section which is alternately bent can effectively weave a support grid with uniform mesh opening size, thereby avoiding the problem that the cutting force of thrombus is reduced or small thrombus escapes due to overlarge or undersize mesh openings. The heat setting process can be carried out in an oven or a fluidized bed.

Referring to fig. 11, the present invention, when involved in a surgical procedure, introduces the stent assembly through the delivery tube 6 into a human blood vessel BV proximate to and through the location of a thrombus PEB. At this time, the transformable support net 1 is always kept in a stretched state inside the duct 6. The outer push rod 4, the inner push rod 3 and the deformable support 1 are pushed out of the delivery pipe 6 by the handle control. When the position of the deformable support net 1 is confirmed to be correct, the relative distance between the inner push rod 3 and the outer push rod 4 is changed through the handle, so that the diameter of the deformable support net 1 is changed from the stretching state to the expansion state. In some cases, after the transformable stent-graft 1 is expanded, the operator judges that the expanded position of the stent-graft is not good. At this time, the deformable support net 1 can be changed into a stretched state again through the handle and withdrawn into the delivery pipe 6, and the support assembly is released again after the release position is adjusted, so that the deformable support net 1 can be recycled. After the deployment position is adjusted, the stent is slowly expanded to the size of the overall diameter which is adapted to the diameter of the blood vessel BV through the handle. The whole body developing structure has developing effect under DSA, and can monitor the contour structure and size change of the deformable support net 1 in the blood vessel BV in real time when being expanded, and assist the operator to perform embolectomy.

With continued reference to fig. 11, after the transformable stent-graft 1 is expanded to an appropriate size in the patient's blood vessel BV, the transformable stent-graft 1 is pulled proximally by the handle. During the dragging, the proximal stent mesh 115 of the transformable stent mesh 1 first passes through the target thrombus PEB and separates the target thrombus PEB from the patient's blood vessel BV. The dense arrangement of the distal stent mesh 116 mesh will allow the captured thrombus mass PEA to be securely enclosed within the deformable stent mesh 1, preventing the thrombus from escaping. As another use of the device, the transformable stent mesh 1 may separate a target thrombus PEB from the wall of a patient's blood vessel BV even when the thrombus adheres to the vessel wall. The deformable support 1 is continuously dragged to pull the thrombus block PEA from the blood vessel BV of the patient to the vicinity of the suction port at the far end of the suction catheter or into the suction catheter, so that the thrombus is sucked out by the suction catheter, or the thrombus is directly pulled out of the body through the suction catheter until the thrombus is completely removed from the body of the patient to realize support thrombus removal. In other examples, the transformable stent 1 may be used to destroy thrombus only, so that the thrombus becomes smaller thrombus blocks, and the thrombus blocks are not required to be enclosed in a stent net, and the thrombus blocks destroyed by cutting are directly sucked out of the blood vessel of the patient by suction. The stent assembly is withdrawn from the patient after the thrombus has been removed. In some cases, if there is a remaining target thrombus PEB left in the patient's blood vessel BV, the above procedure may be repeated after cleaning or replacing the new deformable stent 1 until the remaining thrombus is cleared.

The parameters and features of the first and second embodiments of the present invention may be replaced and/or supplemented without contradiction, and all of them fall within the scope of the embodiments of the present invention, and are not listed here.

In conclusion, the thrombus embolectomy support assembly has the following beneficial effects:

1) The bending state of the near-end support rod enables the contact area of the stent for scraping thrombus in the blood vessel in the axial direction to be larger than that of a conventional straight rod, so that the effect of scraping thrombus by the stent is better;

2) The large opening design of the mesh of the near-end stent is convenient for catching and removing large thrombi. And the strut has reliable structure and good support, and the near end can not collapse in the embolectomy process. The structure has higher thrombus removal effectiveness on large-load thrombus;

3) The radial force of the rod part of the stent is large, so that the stent has better adherence with blood vessels, and thrombus attached to the blood vessel wall can be captured more conveniently during thrombus removal, so that the effect of removing thrombus is cleaner and more complete;

4) Due to the cage-shaped design of the stent, a large thrombus storage space is formed in the stent, so that the thrombus accommodating capacity of the stent is improved, and the thrombus taking efficiency is higher;

5) The expanded state of the stent can be adjusted to meet different vessel diameters by following the adjustment of the handle. Meanwhile, the adjustability of the deformable support net also plays a role in destroying thrombus;

6) The deformable stent mesh has a whole body developing structure, and an operator can judge the current size of the stent by looking up the DSA image in the expansion state, so that the expansion size can be purposefully adjusted to match the diameter of the blood vessel;

7) The deformable support net has high state switching flexibility and can be recycled, and when the release position is not good, the deformable support net can be retracted into the delivery pipe again to readjust the release position.

It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that changes and modifications to the above described embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.

Claims

1. A stent assembly for removing thrombus, comprising:

a deformable stent mesh comprising a proximal stent mesh and a distal stent mesh;

the proximal stent web comprises a plurality of proximal stent rods, the proximal stent rods are bending rods, and the proximal stent rods comprise a proximal constricting part and a proximal expanding part;

the distal stent mesh comprises a plurality of distal stent rods, and the distal stent rods comprise a distal constricting portion and a distal expanding portion;

the proximal and distal dilators are interconnected such that the proximal and distal stent rods are connected to form a cage-like structure.

2. The stent assembly for thrombus removal of claim 1 wherein:

the bending bar includes a plurality of curved arcs to form a continuous curved shape.

3. The stent assembly for thrombus removal as defined in claim 2, wherein:

the width of the two ends of the bending rod is larger than that of the middle of the bending rod.

4. The stent assembly for thrombus removal of claim 1 wherein:

the deformable stent web includes a stretched state and an expanded state in which the proximal stent struts maintain a bent strut configuration.

5. The stent assembly for thrombus removal of claim 1 wherein:

the number of the far-end stent rods is larger than that of the near-end stent rods, so that the mesh density of the far-end stent net is larger than that of the near-end stent net.

6. The stent assembly for thrombus removal of claim 5 wherein:

the mesh size of the proximal stent mesh is larger than the mesh size of the distal stent mesh.

7. The stent assembly for thrombus removal according to any one of claims 1-6, wherein:

the proximal stent mesh comprises a proximal restraint rod and three proximal stent rods, each proximal stent rod further comprises two primary proximal bifurcations, and each primary proximal bifurcation further comprises two secondary proximal bifurcations;

the proximal end restriction rod and the three proximal end support rods form a proximal end restriction part, and the primary proximal end fork and the secondary proximal end fork form a proximal end expansion part.

8. The stent assembly for thrombus removal according to any one of claims 1-6, wherein:

the proximal stent mesh comprises proximal restraint rods and six proximal stent rods, and each proximal stent rod further comprises two primary proximal bifurcations;

the proximal binding rod and the six proximal support rods form a proximal binding part, and the first-stage proximal bifurcation forms a proximal expansion part.

9. The stent assembly for thrombus removal of claim 7 wherein:

the first-stage proximal bifurcation is connected with the second-stage proximal bifurcation, and the second-stage proximal bifurcation is connected with the distal expansion part.

10. The stent assembly for thrombus removal of claim 8, wherein:

the primary proximal bifurcation is directly connected to the distal dilating portion.

11. The stent assembly for thrombus removal as set forth in claim 1, wherein:

the proximal and distal constrictions are each connected to a pusher rod of an embolectomy device for removing thrombi.