CN113693675A - Embolectomy support and manufacturing method thereof - Google Patents

Abstract

Translated fromChinese

本发明提供了一种取栓支架及其制作方法，该取栓支架包括径向可自膨胀、轴向可拉伸的支架主体，所述支架主体包括外层支架和内层支架，所述内层支架设置在所述外层支架内，且所述外层支架与所述内层支架轴向上的近端和远端分别连接，所述内层支架为所述外层支架提供轴向上的支撑力；所述外层支架侧面上还设置有供血栓或凝块进入到所述外层支架内的第一开口。本发明提供的取栓支架采用内外双层设计，在颅内栓塞血管内释放后，依靠内层支架强劲的支撑力，能够即刻打开栓塞组织，恢复栓塞血管的血供，具有即刻恢复血流的效果。

The present invention provides a stent for retrieving a thrombus and a manufacturing method thereof. The stent for retrieving a bolus comprises a radially self-expandable and axially stretchable stent body, the stent body includes an outer layer stent and an inner layer stent, and the inner layer stent is provided. The layer stent is arranged in the outer layer stent, and the outer layer stent is connected with the proximal end and the distal end of the inner layer stent in the axial direction, respectively, and the inner layer stent provides the outer layer stent with an axial direction. The outer layer support is further provided with a first opening for thrombus or clot to enter into the outer layer support. The thrombectomy stent provided by the invention adopts an inner and outer double-layer design. After the intracranial embolized blood vessel is released, relying on the strong supporting force of the inner layer stent, the embolized tissue can be opened immediately, the blood supply of the embolized blood vessel can be restored, and the blood flow can be restored immediately. Effect.

Description

Embolectomy support and manufacturing method thereof

Technical Field

The invention relates to the technical field of medical instrument design, in particular to a thrombus removal support and a manufacturing method thereof.

Background

Acute ischemic stroke, acute pulmonary embolism and deep venous embolism are diseases caused by ischemia and anoxia at the far end of a blood vessel due to the blockage of the blood vessel by thrombus, clot and the like. The diseases have high fatality rate and disability rate. Among them, intracranial vessels are thin, blood paths are tortuous, and embolized vessels are short in length. Pulmonary embolism and deep venous embolism have thicker blood vessels and smoother blood paths, but the number of embolized clots and thrombus is usually more, and the blood vessels in embolized sections are longer.

Acute Ischemic Stroke (CIS) is a nerve tissue injury caused by Ischemic necrosis of local brain tissue due to sudden blockage of blood flow in the brain. Emboli or thrombus blockage is seen in 70-80% of patients with severe symptoms who require arteriography. The lethality of larger vessel embolism is 53% -92%.

Pulmonary artery embolism (PE) refers to the endogenous or exogenous emboli blocking the pulmonary artery or its branches causing the pulmonary circulatory disturbance of clinical and pathophysiological syndrome. The most important and common kind of the pulmonary embolism (PTE) is pulmonary arterial thrombosis, and pulmonary hemorrhage or necrosis after pulmonary arterial thrombosis is called pulmonary infarction. Pulmonary artery embolism is an acute condition with high clinical morbidity and mortality, and the pulmonary artery thromboembolism is caused most frequently. According to incomplete statistics, 35.5 ten thousand patients with pulmonary embolism exist in China at present.

The vascular recanalization is the key to treat acute ischemic stroke and acute pulmonary embolism. The conventional methods for treating acute ischemic stroke at present comprise interventional thrombolysis and mechanical thrombus removal, wherein the mechanical thrombus removal is divided into stent thrombus removal and suction thrombus removal.

At present, the stent thrombus removal and suction thrombus removal of intracranial vascular embolism are clinically accepted, have the same effect as interventional thrombolysis, and have the advantage of long time window, compared with 3h of interventional thrombolysis, the stent thrombus removal and suction thrombus removal is expanded to 24 h. And the treatment technology of taking the thrombus by the bracket and matching with the suction thrombus is also widely popularized.

The thrombus extraction bracket similar to the intracranial thrombus extraction bracket structure can also be applied to interventional thrombus extraction operations of pulmonary embolism and deep venous embolism.

The development of intracranial interventional embolectomy stents has been for many years, and the development has experienced Merci spring coil type structures, Catch basket type structures, cutting stent type structures with two closed ends of Revice SE, cutting stent type structures with two open ends of TreVo, both open ends of Solitaire FR side edges and one open side, Versi three-segment type, Eric multi-segment filter combination, Punamber 3D multi-segment interception type, Phenex multi-segment brush type, internal and external double layers of Embotrap II, both open sides, distal basket type, Aperio distal end open, proximal end closed, open leaves on the stent, inner guide wire development type, Tigertriever-13 outer woven stent, inner movable guide wire, and adjustable length and diameter of the stent through the control of the guide wire by a handle.

In terms of processing technology, the embolectomy support mainly comprises 4 steps: firstly, weaving or cutting a bracket, wherein main raw materials are a NiTi alloy wire and a NiTi alloy pipe respectively; secondly, heat treatment shaping, namely shaping the bracket into a target shape and size; polishing, namely removing oxide skin on the surface of the bracket to form smooth inner and outer surfaces; and fourthly, assembling, namely connecting the bracket and the pushing rod together.

The main working principle of the intracranial thrombus taking support is to capture thrombus or clot and take the thrombus or clot out of the body, so that the originally embolized blood vessel is unobstructed, the blood flow is recovered, the injury of the blood vessel is not caused, and the embolization of a finer far-end blood vessel is realized. In order to achieve the effect of recovering the blood flow of the embolized blood vessel, the thrombus removal stent needs to solve the problems in the aspect of 3: first, the stent can reach the vascular embolization site, which requires the stent to have a sufficiently small outer diameter and suitable radial support force; secondly, the thrombus and clot of the thrombus taking stent are captured as much as possible, so that embolic materials can enter the stent and be taken out; thirdly, the thrombus and the clot which are captured by the thrombus taking stent do not fall off when passing through a tortuous intracranial blood vessel in the process that a doctor retracts the push rod and pulls the thrombus taking stent like a recovered sheath;

the ideal intracranial thrombus removal stent can reach a narrow intracranial blood vessel at the far end without damaging the blood vessel, so as to capture thrombus and/or clot as much as possible, and the captured thrombus and/or clot can be firmly captured by the thrombus removal stent through the tortuous blood vessel in the process of withdrawing the thrombus removal stent without falling off.

The thrombus taking stent products on the market at present can only reach thicker blood vessels, emboli or clots with smaller size, softer texture and short coagulation time are collected, the positions of the blood vessels where the emboli are located are not too tortuous, or the blood vessels cannot be unobstructed due to one-time thrombus taking, only a small amount of thrombus can be taken out once, and the thrombus taking needs to be repeatedly taken out for many times. These stent-grafts are more or less defective, too large in size to be placed in the thinner distal vessels; the radial supporting force is too large, the micro catheter is not easy to push, and the blood vessel is damaged after the micro catheter is released; the inability to capture large size, high viscosity thrombi or clots; in the process of withdrawal, thrombus or clot falls off seriously through the tortuous vessels, and the fallen thrombus floats to farther and thinner vessels to generate embolism again, thereby influencing the prognosis effect of patients. Therefore, both patients and doctors need a thrombus removal support which can solve the problems.

Disclosure of Invention

Aiming at the problems in the background art, the invention provides a thrombus removal support which comprises a radially self-expandable and axially stretchable support main body, wherein the support main body comprises an outer support and an inner support, the inner support is arranged in the outer support, the outer support is respectively connected with the axially proximal end and the axially distal end of the inner support, and the inner support provides an axially supporting force for the outer support; and a first opening for the thrombus or the clot to enter the outer-layer stent is also arranged on the side surface of the outer-layer stent.

Preferably, the outer layer bracket is an elongated net-shaped cylindrical structure with two ends folded.

Preferably, the outer layer bracket is formed by sequentially connecting a plurality of bracket units, and the first opening is respectively arranged on two symmetrical sides of each bracket unit.

Preferably, each of the support units has a structure symmetrical up and down and left and right.

Preferably, in each of the holder units, the area of the first opening portion is 0.8 to 1.5 times the area of the non-opening portion.

Preferably, each of the stent units has the same structure, and two adjacent stent units are connected by rotating the angle α in the circumferential direction.

Preferably, the value of the angle alpha ranges from 0 to 90 degrees.

Preferably, the connecting point of two adjacent bracket units is discontinuous on the same connecting line parallel to the axial direction.

Preferably, the inner layer bracket comprises at least one supporting section and at least one telescopic section which are connected, and the telescopic section is used for compensating the whole length of the inner layer bracket.

Preferably, the inner stent comprises a support section and a telescoping section, the support section being located at the proximal end and the telescoping section being located at the distal end.

Preferably, the inner layer support comprises a plurality of supporting sections, and the telescopic section is arranged between the adjacent supporting sections.

Preferably, the telescopic section is a spring tube which can be axially stretched.

Preferably, the telescopic section is a cross-shaped structure with the size adjustable along the length direction of the inner layer bracket.

Preferably, the support section is an expandable network-like structure.

Preferably, the proximal end of the stent body tapers from the distal direction to the proximal direction.

Preferably, the holder main body is provided with a first developing portion.

Preferably, the stent further comprises a catching structure for catching thrombus or clot escaping from the stent body, the catching structure is connected to the distal end of the stent body, and one end of the catching structure facing the stent body is provided with a second opening.

Preferably, the catching structure is in a shuttle-shaped network structure.

Preferably, the harvesting structure is connected to the distal end of the outer stent.

Preferably, the catching structure is provided with a second developing part.

Preferably, an extension rod is arranged at one end of the catching structure, which faces away from the bracket main body, and the second developing part is arranged on the extension rod.

Preferably, the bracket further comprises a push rod, and the push rod is connected with the proximal end of the bracket main body.

Preferably, the push rod is provided with a third developing part.

The invention also provides a manufacturing method of the thrombus removal support, which is used for processing the thrombus removal support and comprises the following steps:

s1, processing each component of the bolt taking bracket independently;

s2, carrying out heat treatment setting on each processed component;

s3, carrying out acid washing and electrochemical polishing treatment on each component;

s4, arranging a developing material on each component;

and S5, assembling and connecting the promoting components to form the complete embolectomy support.

Preferably, the step S1 further includes: and respectively processing each component by adopting laser cutting of a metal structure, laser engraving of the metal structure or weaving of metal wires.

Preferably, the step S1 further includes: each component comprises an outer layer bracket, an inner layer bracket, a fishing structure and a push rod.

Preferably, the step S2 further includes: the outer layer stent and the catching structure are subjected to heat treatment and shaping together to expand the diameter, the inner layer stent is subjected to heat treatment and shaping alone to expand the diameter, and the expansion amount of the inner layer stent is smaller than that of the outer layer stent;

preferably, the step S2 further includes: the outer layer bracket, the fishing structure and the inner layer bracket need to be subjected to heat treatment setting for many times, so that the diameters of the outer layer bracket, the fishing structure and the inner layer bracket are gradually expanded to target values.

Preferably, the step S2 further includes: in the process of heat treatment and shaping of each component, the original air in the heat treatment space is firstly emptied, and then inert gas is filled into the heat treatment space, so that the closed state of the heat treatment space is ensured in the treatment process.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:

1. the thrombus taking bracket provided by the invention adopts an inner-outer double-layer design, and after the thrombus taking bracket is released in an intracranial thrombus blood vessel, the thrombus tissue can be opened immediately by the strong supporting force of the inner-layer bracket, the blood supply of the thrombus blood vessel is recovered, and the thrombus taking bracket has the effect of immediately recovering blood flow;

2. the side edge of the outer layer stent of the thrombus taking stent provided by the invention can be better embedded into thrombus or clot after the thrombus taking stent is released, and when the thrombus taking stent is withdrawn, the thrombus or clot positioned on the outer side of the whole stent can roll, slide and extrude into the inside of the thrombus taking stent in the sliding process and is wrapped between the inner layer stent and the outer layer stent, so that the higher wrapping rate of the thrombus or clot is realized;

3. the design of the inner-layer and outer-layer double-layer brackets of the embolectomy bracket can maintain the original length without large axial deformation due to strong axial supporting force of the inner-layer bracket when the embolectomy bracket is retracted and the integral bracket receives pulling force. This allows the overall stent, and particularly the outer stent, to be subjected to reduced pulling forces without significant axial deformation. The stent has the advantages that the shape of the original stent can be maintained without great change when the stent is subjected to pulling force, so that the internal space is kept unchanged, the thrombus which is captured by the thrombus taking stent can be firmly clamped in the space formed by the inner and outer double-layer stents without falling off or escaping, and the stent has higher thrombus entrapment rate and entrapment stability in recovery;

4. the inner and outer double-layer design of the thrombus taking support provided by the invention can be extruded by the inner wall of a tortuous blood vessel when the thrombus taking support passes through the tortuous intracranial blood vessel when the thrombus taking support is withdrawn. At the moment, due to the double-layer design of the stent, the inner-layer stent is close to the side wall of the blood vessel, and the outer-layer stent is pushed out to the outer side of the blood vessel wall to form an expanded arc shape, so that the advantage of the design is that the stent is prevented from being integrally flattened to remarkably reduce the space in the stent, so that the captured thrombus or clot is extruded out of the stent, falls off and escapes, and the stent has the capability of resisting the pressure of the side wall of a tortuous blood vessel and maintaining the internal space of the thrombus taking stent;

5. the thrombus taking support provided by the invention is also provided with a catching structure for intercepting thrombus or clot escaping from the support main body; in the process of withdrawing and retracting the thrombus stent into the sheath tube, if the thrombus is extruded, broken and falls off, the catching structure is used as a protection tool, the fallen thrombus or clot can be captured again, the escape of emboli is reduced, the risk that the intracranial far-end blood vessel blocks the blood vessel again due to the fallen emboli is reduced, and the thrombus-taking sheath tube protection tool is an effective protection tool.

Drawings

The above and other features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front view of a thrombectomy stent provided in example 1 of the present invention;

FIG. 2 is a top view of a thrombectomy stent provided in example 1 of the present invention;

FIG. 3 is a front view showing the connection of an outer bracket and a fishing structure in example 1 of the present invention;

FIG. 4 is a top view of the connection of the outer support and the fishing structure in embodiment 1 of the present invention;

FIG. 5 is a schematic structural view of an inner layer support in example 1 of the present invention;

FIG. 6 is a front view of a bolt support in example 2 of the present invention;

fig. 7 is a schematic structural view of an inner layer support inembodiment 2 of the present invention.

Detailed Description

The present invention will be described in more detail below with reference to the accompanying drawings, which illustrate embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

The invention provides a thrombus taking support which is used for collecting clots and thrombus in blood vessels, dredging the blood vessels and recovering blood flow, is mainly used for intracranial blood vessels, pulmonary artery blood vessels, deep vein blood vessels and the like, solves the problems that the clots are difficult to capture, easy to fall off and escape during collecting the clots, and can better meet the clinical use requirements.

Specifically, the thrombus removal support comprises a support main body which can radially self-expand and axially stretch, the support main body comprises an outer support and an inner support, the inner support is arranged in the outer support, the outer support is respectively connected with the axial near end and the axial far end of the inner support, and the inner support provides axial supporting force for the outer support; the side surface of the outer layer bracket is also provided with a first opening for the thrombus or the clot to enter into the outer layer bracket.

Before use, the thrombus taking support is folded in a loading sheath; when the thrombus taking bracket is used, the thrombus taking bracket is pushed into the micro catheter through the loading sheath and then pushed out to the position of an embolism in a blood vessel from the far end of the micro catheter, the thrombus taking bracket slowly expands by itself and is embedded into thrombus or clot, and the thrombus or clot slides into the thrombus taking bracket from the first opening. The compressed degree or the self-expansion degree of the embolectomy stent is mainly influenced by the thickness of a blood vessel at the position, and the thinner the blood vessel is, the larger the compressed degree is, and the smaller the self-expansion degree of the embolectomy stent is; the propping degree of the thrombus taking support is also influenced by the texture of the thrombus or clot at the position, and the softer and looser the texture of the thrombus or clot is, the larger the propping degree of the thrombus taking support is; the harder and denser the texture of the thrombus or clot, the smaller the strut degree of the thrombus removal stent; usually, the thrombus taking stent stays for 3min to 5min after being released, so that the thrombus taking stent is spread as much as possible, and more thrombus or clot tissues are embedded into the thrombus or clot tissues and are fully combined with the thrombus stent.

When the thrombus taking support is recovered, the thrombus taking support is subjected to the traction force of the near end and gradually withdraws from the intracranial blood vessel with the thinner far end to the internal carotid blood vessel with the thicker and thicker far end, and the thrombus taking support is gradually expanded from a compressed state to a completely self-expanded state gradually, wraps and holds the captured thrombus or clot and is completely expanded. Finally, the thrombus taking support is pulled, the whole wrapped trapped thrombus or clot is pulled into a recovery sheath (balloon catheter), and the thrombus or clot is taken out of the body. The thrombus and clot captured by the thrombus taking support are easy to fall off and escape; the stent main body adopts a double-layer structure, the axial supporting force of the inner-layer stent is strong, strong resistance can be provided when the inner-layer stent is dragged, the length and the diameter of the outer-layer stent are kept almost unchanged, the thrombus captured by the thrombus stent is not easy to fall off and escape even if the thrombus stent is subjected to pulling force and extrusion of the side wall of the blood vessel when the thrombus stent is withdrawn.

The thrombus removal support provided by the invention has the following advantages:

1. the thrombus taking bracket provided by the invention adopts an inner-outer double-layer design, and after the thrombus taking bracket is released in an intracranial thrombus blood vessel, the thrombus tissue can be opened immediately by the strong supporting force of the inner-layer bracket, the blood supply of the thrombus blood vessel is recovered, and the thrombus taking bracket has the effect of immediately recovering blood flow;

2. the side edge of the outer layer stent of the thrombus taking stent provided by the invention can be better embedded into thrombus or clot after the thrombus taking stent is released, and when the thrombus taking stent is withdrawn, the thrombus or clot positioned on the outer side of the whole stent can roll into, slide into, squeeze into and be embedded into the thrombus or clot in the sliding process, and is wrapped between the inner layer stent and the outer layer stent, so that the higher wrapping rate of the thrombus or clot is realized;

3. the design of the inner-layer and outer-layer double-layer brackets of the bolt taking bracket provided by the invention can maintain the original length without generating larger axial deformation due to stronger axial supporting force of the inner-layer bracket when the bolt taking bracket is retracted and the integral bracket receives pulling force. This allows the overall stent, and particularly the outer stent, to be subjected to reduced pulling forces without significant axial deformation. The stent has the advantages that the shape of the original stent can be maintained without great change when the stent is subjected to pulling force, so that the internal space is kept unchanged, the thrombus which is captured by the thrombus taking stent can be firmly clamped in the space formed by the inner and outer double-layer stents without falling off or escaping, and the stent has higher thrombus entrapment rate and entrapment stability in recovery;

4. the inner and outer double-layer design of the thrombus taking support provided by the invention can be extruded by the inner wall of a tortuous blood vessel when the thrombus taking support passes through the tortuous intracranial blood vessel when the thrombus taking support is withdrawn. At the moment, due to the double-layer design of the stent, the inner-layer stent is close to the side wall of the blood vessel, and the outer-layer stent is pushed out to the outer side of the blood vessel wall to form an expanded arc shape, so that the advantage of the design is that the stent is prevented from being integrally flattened to remarkably reduce the space inside the stent, so that the captured thrombus or clot is extruded out of the stent, falls off and escapes, and the capability of resisting the pressure of the side wall of the tortuous blood vessel and maintaining the internal space of the thrombus taking stent is realized.

The following further description is made with respect to specific embodiments:

example 1

Referring to fig. 1-5, the present embodiment provides a thrombus removal stent, which includes a radially self-expandable and axially stretchable stent body, the stent body includes an outer stent 1 and aninner stent 2, theinner stent 2 is disposed in the outer stent 1, the outer stent 1 is connected to the axially proximal end and the axially distal end of theinner stent 2, and theinner stent 2 provides an axially supporting force for the outer stent; the side surface of the outer stent 1 is also provided with a first opening for the thrombus or the clot to enter into the outer stent.

In this embodiment, the outer stent 1 is a slender network-shaped cylindrical structure with two ends folded, and the distal end of the outer stent 1 is closed, that is, the proximal end and the distal end of the outer stent 1 are folded, so that the design is favorable for enabling the distal end to be used as a fishing net structure, that is, when the first opening on the side of the outer stent 1 is large enough, the closed design of the distal end can play a role in fishing net. Further, the proximal end of the preferred outer stent 1 may also be closed; of course, in other embodiments, the proximal end of the outer stent 1 may be in an open state, i.e., not collapsed, and in an open state.

Specifically, the outer stent 1 is formed by sequentially connecting a plurality of stent units, for example, the outer stent 1 shown in fig. 3 to 4 includes five stent units, i.e., astent unit 101, astent unit 102, astent unit 103, astent unit 104, and astent unit 105, which are sequentially connected to each other to form a continuous segmented structure. The number of the stent units included in the outer stent 1 is not limited herein, and can be adjusted according to specific situations, and generally includes 2-5 stent units; wherein, the support units are integrally manufactured to form a complete outer support.

Furthermore, the structure of each support unit is the same, and each support unit is a structure which is symmetrical up and down, left and right.

Furthermore, two adjacent bracket units are connected by rotating the angle alpha in the circumferential direction; the value range of the alpha angle is 0-90 degrees; the preferred angle alpha is 90 deg. so that the connection points of two adjacent stent units are discontinuous on the same line parallel to the axial direction, as shown in fig. 3-4. In the embodiment, a plurality of repeated stent units in the outer stent are designed into an alternate 90-degree rotating structure instead of continuous repeated units, so that the flexibility of the outer stent is increased, and the embolectomy stent can better adapt to the 3D structure bending configuration of a blood vessel when passing through a tortuous blood vessel, and the blood vessel is not injured due to forced straightening of the blood vessel under the rebounding effect of the stent, so that the immediate recanalization effect after the operation is good, and the healing effect is poor.

Of course, in other embodiments, the connection manner of the brackets of the respective bracket units is not limited to the above, and may also be adjusted according to specific situations, and is not limited herein.

Further, first openings are provided on both symmetrical sides of each holder unit, and it is preferable that the area of the first opening portion is 0.8 to 1.5 times the area of the non-opening portion. The design enables each stent unit to have a larger first opening, so that thrombus or clot can be more easily fallen into the outer stent 1.

In this embodiment, the material of the outer stent 1 is preferably NiTi alloy, which has superelasticity and shape memory property, and can remember the shape after being heat-treated and shaped, so that the outer stent 1 made of NiTi alloy also has superelasticity and shape memory property, and can recover the original shape after being contracted into a very small sheath and pushed a certain distance, as long as the applied external force is removed.

Further, the outer layer bracket can be made of a NiTi alloy pipe by using a laser engraving or laser cutting processing technology; or the outer layer bracket 1 can be made of NiTi alloy wires by a weaving process; or the outer layer bracket 1 can be made of a combination of a NiTi alloy pipe and a NiTi alloy wire by a processing technology of a combination of laser engraving, hand knitting and laser cutting. The processing method of the outer stent 1 can be selected according to specific needs, and is not limited herein.

Of course, in other embodiments, the outer stent 1 may be made of other materials with elastic and shape memory characteristics, which is not limited herein.

In this embodiment, referring to fig. 4-5, theinner stent 2 comprises asupport section 201 and atelescoping section 202 connected together, thesupport section 201 being located at a proximal end, thetelescoping section 202 being located at a distal end, and the proximal end of thesupport section 201 being open to facilitate collection of thrombus or clot.

The present embodiment mainly utilizes the supportingsection 201 to mainly achieve the effect of forming by force and the function of stretching resistance. When the thrombus removal stent is released, the strong supporting force of the inner stent can instantly open a blood flow passage at the thrombus position to recover the blood flow, and thetelescopic section 202 also has the effect, but the effect of thetelescopic section 202 for recovering the blood flow is inferior to that of the supportingsection 201. Thetelescopic section 202 mainly plays a role in length compensation when the thrombus taking support is retracted into the sheath tube; the specific outer-layer bracket has a large diameter, the diameter of the bracket is remarkably changed when the sheath is retracted, the outer-layer bracket is remarkably reduced in radial dimension in order to be retracted into the sheath, but is remarkably increased in axial dimension, and because the inner-layer bracket and the outer-layer bracket are connected with each other at the near end and the far end, at the moment, in order to keep the uniformity of the dimensional change in the axial direction, thetelescopic section 202 of the inner-layer bracket is remarkably lengthened by tensile force, the same elongation as that of the outer-layer bracket is kept, and finally, the embolectomy bracket is smoothly retracted into the sheath.

In this embodiment, the supportingsection 201 is preferably an expandable network-like structure, and the telescopic section 203 is preferably an axially retractable spring tube; of course, in other embodiments, themanufacturing section 201 and the telescopic section 203 may also adopt other structural designs, and are not limited herein.

In this embodiment, the supportingsection 201 and thetelescopic section 202 are integrally formed, and the supportingsection 201 and thetelescopic section 202 are naturally transited and tightly connected, and are made of different cutting or weaving forms of the same material without splicing.

Wherein, there is great diameter difference betweensupport section 201 and theflexible section 202, andsupport section 201 is thicker, and the diameter is (1 ~ 1.5) mm usually, andflexible section 202 diameter is thinner, and the diameter is (0.2 ~ 0.3) mm.

Furthermore, the ratio of the length of thetelescopic section 202 to the length of the whole embolectomy support is (1/2-1/4). Since the outer stent and the inner stent are finally assembled together, the lengths thereof are the same in the expanded state and the lengths thereof are the same in the contracted state. The diameter of the outer layer support in the expansion state is obviously larger than that of the inner layer support, and under the condition that the inner layer support is not specially designed for length compensation, if the lengths of the inner layer support and the outer layer support in the expansion state are consistent, the length of the outer layer support in the contraction state is longer than that of the inner layer support due to large deformation. The solution at this time is to add a telescopic section to the inner layer bracket. In the contraction state, the length of the inner layer bracket is compensated by the extension of the telescopic section, so that the length of the inner layer bracket is consistent with that of the outer layer bracket.

However, the length of theexpansion section 202 cannot be excessively long because theinner stent 2 does not play a role of limiting the entire length of the outer stent 1 during the withdrawal and when passing through a tortuous blood vessel after the ratio of the length of theexpansion section 202 in the entire inner stent exceeds 1/2. That is, the elastic force of thetelescopic section 202 is slightly larger than the traction force applied when the stent is retracted, so as to achieve the effect of limiting the outer stent from deforming. Meanwhile, thetelescopic section 202 cannot be too short, the too short stent needs larger deformation of the spring when being contracted, the larger deformation needs larger traction force, the thrombus taking stent is operated in a blood vessel and a sheath tube, the distance from the proximal end to the distal end of the guide wire is as much as 2 meters, a user is difficult to overcome the larger force to recover the stent, and the stent cannot be recovered possibly. Therefore, the length of thetelescopic section 202 is designed to be (1/2-1/4) in the ratio of the length of the whole embolectomy stent.

Of course, in other embodiments, the values of the diameters and the lengths of the supportingsection 201 and thetelescopic section 202 can be adjusted according to specific situations, and are not limited herein.

In this embodiment, theinner stent 2 may also be made of a NiTi alloy material.

Specifically, theinner stent 2 may have a braided structure of a plurality of strands of NiTi wires, the number of strands of NiTi wires is n, n is in the range of 1 to 10, and n is 3/4/5/6. Theinner layer support 2 can also be a wire wound spring structure, for example: NiTi wire wound spring, platinum-iridium alloy wire or platinum-tungsten alloy wire, stainless steel wire, gold wire, etc. provide tensile force and certain elasticity. Due to the fact that the NiTi wire is large in deformation amount and small in deformation force, large length compensation can be achieved through a small occupation ratio, and meanwhile traction force is not increased remarkably.

Theinner layer bracket 2 can also be an assembly of a NiTi alloy pipe cutting bracket and a NiTi wire wound yellow spring, the supporting end is the NiTi alloy pipe cutting bracket, the telescopic section is the NiTi wire wound yellow spring, and the combination mode of the combination position of the NiTi alloy pipe cutting bracket and the telescopic section can be mechanical riveting, joggle joint, glue bonding, laser welding or combination of various combination modes.

Of course, in other embodiments, the processing method of theinner layer bracket 2 can be selected according to specific needs, and is not limited herein.

Of course, in other embodiments, theinner layer support 2 may be made of other materials with elastic and shape memory properties, which is not limited herein.

In the embodiment, the proximal end of the outer stent 1 is connected with the proximal end of theinner stent 2, and the distal end of the outer stent 1 is connected with the distal end of theinner stent 2 to form a stent main body; and only the near end and the far end between the outer layer bracket 1 and theinner layer bracket 2 are connected with each other, and the middle section has no mutual combination sites, so that the inner layer bracket can realize the compensation in length.

The connection mode between the outer layer bracket 1 and theinner layer bracket 2 can be nesting of a mechanical structure, physical press-holding connection, a metal lantern ring, laser welding, adhesive bonding and the like, can be one of the connection modes, and can also be a combination of multiple connection modes, and the connection mode is not limited here and can be adjusted according to specific needs.

In the embodiment, the whole proximal end of the stent main body is tapered from the distal direction to the proximal direction so as to be in a smooth slender shape, so that the pulling force required by an operator in the process of recovering the thrombus stent is gradually increased instead of being sharply increased in a cliff manner, and the thrombus stent and the clot can be favorably and smoothly recovered; instead of being clamped at the opening of the sheath tube, the force is required to be larger, the force suddenly breaks through the threshold value, and the thrombus removal support is suddenly pulled into the sheath tube; the condition that the sudden breakthrough threshold is recovered can cause the following 2 adverse results, (1) the weak strut of the thrombus taking stent can not bear the gradually accumulated pulling force, and is pulled off to puncture the blood vessel, thereby causing intracranial or internal carotid artery hemorrhage; (2) the thrombus taking support and the blood vessel wall are quickly rubbed to damage the inner wall of the blood vessel, or the inner wall of the blood vessel is clamped when the thrombus taking support is crowded, and the inner wall of the blood vessel is torn when a threshold value is suddenly broken through; these adverse consequences can be surgical failures, or serious complications.

In this embodiment, the thrombectomy stent further comprises a catchingstructure 2 for intercepting thrombi or clots that escape from the stent body, the catchingstructure 2 being attached to the distal end of the stent body. In the process of withdrawing and retracting the thrombus stent into the sheath, if the thrombus is extruded, broken and falls off, the catchingstructure 2 is used as a protection tool, and can capture the fallen thrombus or clot again, reduce the escape of emboli, reduce the risk that the intracranial far-end blood vessel blocks the blood vessel again due to the fallen emboli, and is an effective protection tool.

The catchingstructure 3 is of a fusiform network structure, has dense meshes and is used for intercepting fine thrombi and clots which fall off and escape from the main body part of the thrombus taking support in the dragging process; the proximal end of the catchingstructure 3 is open and the distal end is closed, i.e. the end of the catchingstructure 3 facing the holder body has a second opening.

Wherein, thefishing structure 3 is connected with the far end of the outer bracket 1; specifically, the far-end fishing net of the embolectomy support and the outer support of the main body part are in natural transition and tight connection, are in different cutting or weaving forms of the same material, and are not spliced. Furthermore, the connecting end between thefishing structure 3 and the outer layer bracket 1 adopts a design of a hypotube.

Of course, in other embodiments, the catchingstructure 3 may also be connected to the distal end of theinner stent 2, or both theinner stent 2 and the distal end of the outer stent 1, and is not limited herein and may be adjusted according to specific needs.

Wherein, the maximum diameter of the catchingstructure 3 is consistent with the outer layer bracket 1 drawn by the bracket and is (3-6) mm. The outer diameter of the main body bracket of the bolt taking bracket with the same model and specification is the same as that of the catchingstructure 3, and the tolerance of the outer diameter size is not more than 0.25 mm.

Of course, the arrangement of the catchingstructure 3 may be omitted in other embodiments, which are not limited herein.

In this embodiment, the thrombectomy support further comprises a push rod, wherein the push rod is connected with the proximal end of the support main body and is used for pushing or taking out the support main body.

The connection mode between the push rod and the bracket main body can be nesting of a mechanical structure, physical pressing connection, a metal lantern ring, laser welding, adhesive bonding and the like, can be one of the connection modes, can also be a combination of multiple connection modes, can be selected according to specific conditions, and is not limited here.

The material of the pushing rod is NiTi alloy wire (rod), which can be a single thick metal rod or a metal rope woven by multiple strands of thin metal wires, and the number of the metal wires used by the metal rope can be 2/3/5/7/9; or the material of the push rod can also be a single or multi-strand stainless steel wire; or the material of the push rod can also be a plurality of NiTi alloy wires and stainless steel wires which are mixed and woven; or the material of the push rod can also be a single metal push rod formed by butt welding and splicing a single NiTi alloy rod and a single stainless steel rod.

Furthermore, the push rod can be divided into an inner layer and an outer layer, the inner layer is a single metal rod, the outer layer is a multi-strand metal wire, and the multi-strand metal wire can be of a woven structure or a wound spring structure.

The specific material and the manufacturing method of the push rod in the embodiment can be adjusted according to specific needs, and are not limited here.

In this embodiment, one end of the push rod connected to the stent main body is cylindrical, round bar-shaped or spherical, and is used for being inserted into, matched and connected with an opening on the stent main body, and one end of the push rod is specifically formed into a cylindrical structure by directly grinding a NiTi wire, or welded into a sphere by adopting a laser fusion mode, or sleeved with a biocompatible heat-shrinkable tube at the end of the NiTi wire to be heat-shrunk into a round bar; the form of the end of the push rod is not limited to the above, and may be adjusted according to circumstances.

In other embodiments, of course, one end of the pushing rod connected to the stent main body is a circular ring structure for being inserted into and connected with the plug-in unit on the stent main body in a matching manner, and the specific circular ring structure may be a circular ring structure made of stainless steel or platinum or other materials, or may be a biocompatible polymeric ring, which is not limited herein.

In this embodiment, the thrombus removal support is further provided with a plurality of developing parts, so that the using process of the thrombus removal support can be observed conveniently.

Wherein, the main bracket is provided with a first developing part; specifically, the near end, the middle section and the far end of the outer layer bracket 1 and theinner layer bracket 2 are uniformly provided with first developing parts.

Wherein, the catchingstructure 3 is provided with a second developing part; specifically,catch structure 3 and serve and be provided with the extension rod on one of support main part dorsad, the second part of developing sets up on the extension rod, and this extension rod still has the function of direction simultaneously except having the function of developing, and further this extension rod still has soft characteristic. The extension rod can be of a multilayer structure, the inner layer is a single NiTi rod or a plurality of strands of NiTi wires, the outer layer is provided with at least one layer of developing wire spring winding shaft, and the inner layer of the optimized thin extension rod can also be made of stainless steel materials; the selection of the material and the structure of the extension rod can be adjusted according to specific conditions, and the material and the structure are not limited here.

Of course, in other embodiments, the extension rod may be omitted, and the developing part may be directly disposed at both ends of the catching structure, and may be adjusted according to specific situations, which is not limited herein.

Wherein, be equipped with the third portion of developing on the push rod, specific third portion of developing arranges in push rod distal end and support main part hookup location.

In this embodiment, the first developing part, the second developing part and the third developing part may be specifically one or more of a developing wire, a developing point, a developing sheet, a developing rod or a developing ring; when the first developing part, the second developing part and the third developing part are developing wires, the developing wires can be connected to the embolectomy bracket in a weaving mode; when the first developing part, the second developing part and the third developing part adopt developing points, developing sheets, developing rods or developing rings, one or a combination of a plurality of connecting modes of a winding spring, nesting of mechanical structures, physical pressing connection, a metal lantern ring, laser welding, adhesive bonding (the adhesive can be glue such as lotai 4011 glue or lotai 4031 glue) and the like can be adopted for connecting the first developing part, the second developing part and the third developing part to the bolt taking support.

Furthermore, the materials of the first developing part, the second developing part and the third developing part can be platinum-tungsten alloy, platinum-tungsten alloy sheets and/or platinum-tungsten alloy wires, the shadow materials can also be gold, platinum-iridium alloy, tungsten, tantalum and the like, metal sheets, and metal dots formed by metal powder and a binder such as glue and the like; the developing material is selected according to the position and the developing effect, and is not limited herein.

Example 2

Referring to fig. 6 to 7, this embodiment is an adjustment based on embodiment 1.

In this embodiment, the inner frame 2 'includes a plurality of supporting sections 201', and a telescopic section 202 'for compensating the overall length of the inner frame 2' is additionally disposed between adjacent supporting sections.

The lengths of the supporting sections 201' may be the same or different, and are not limited herein and may be adjusted according to specific situations.

Wherein the support section 201' preferably employs an expandable network-like structure; of course, in other embodiments, themanufacturing section 201 and the telescopic section 203 may also adopt other structural designs, and are not limited herein.

Wherein, the telescopic section 202 'is a structure with adjustable size along the length direction of the inner layer bracket 2'; in this embodiment, the telescoping section 202 'is a "cross-hair" type structure, which has a reduced radial dimension and an increased axial dimension when the inner stent 2' is stretched in the length direction. Of course, in other embodiments, the telescopic section 202' may also be implemented by using a spring tube, etc., which is not limited herein and may be adjusted according to specific situations.

In the same embodiment, the supportingsection 201 and thetelescopic section 202 are integrally manufactured, and the supportingsection 201 and thetelescopic section 202 are naturally transited and tightly connected, are in different cutting or weaving forms of the same material, and are not spliced.

Example 3

This example provides a method of making a thrombectomy holder, which is used to manufacture the thrombectomy holder described in example 1.

The manufacturing method of the thrombus taking bracket in the embodiment is as follows:

and S1, processing each component of the bolt taking bracket independently.

Wherein, each component comprises an outer layer bracket, an inner layer bracket, a catching structure and a push rod; when the fishing structure and the push rod are not arranged, the processing process can be omitted;

wherein, the components are respectively processed by adopting laser cutting of a metal structure, laser engraving of the metal structure or weaving of metal wires. Furthermore, the femtosecond laser engraving machine is needed for laser engraving, and the high-precision machining process of the bolt-taking support is guaranteed.

And S2, performing heat treatment setting on each processed component.

Wherein, the outer layer bracket and the catching structure are subjected to heat treatment, shaping and diameter expansion together, and the inner layer bracket is subjected to heat treatment, shaping and diameter expansion alone because the telescopic section in the inner layer bracket does not need to be expanded,

wherein the expansion amount of the inner layer stent is less than that of the outer layer stent; specifically, the diameters of the outer-layer stent and the far-end fishing structure need to be expanded to a target size from the size of the cutting pipe, the expansion multiple of the diameters is 6-12 times, and the expansion amount is large; the inlayer support only supports the section and needs the diameter expansion, and flexible section need not expand, supports the diameter of section and need expand the target dimension from cutting pipe size, and the expansion multiple ofdiameter 3 ~ 6 times, the expansion number is less than the skin.

Wherein, the outer layer bracket, the fishing structure and the inner layer bracket need to be shaped by heat treatment for a plurality of times, so that the diameters of the outer layer bracket, the fishing structure and the inner layer bracket are gradually expanded to target values.

Specifically, because the expansion amount of the outer-layer stent and the far-end fishing net is large, the heat treatment is carried out for multiple times, the diameter of the stent is gradually expanded to a target size, and the heat treatment and shaping times are 3-6 times; and the temperature and the time are different for each heat treatment and shaping, and the specific heat treatment parameters are shown in table 1.

Table 1 shows the heat treatment parameters of the outer stent of the embolectomy stent and the distal fishing net:

the inner-layer stent only needs to be subjected to heat treatment for shaping and expanding the diameter, and the cutting tube can be supported to a target size after 1-3 times of heat treatment for shaping due to small expansion amount. Specific heat treatment parameters are shown in table 2.

Table 2 shows the heat treatment parameters of the inner layer stent of the thrombus removal stent:

of course, in other embodiments, the number of heat treatments of the inner and outer stents is not limited to the above; the number of times of heat treatment of the inner and outer layer stents can be determined according to the model specification of an actual sample, and the principle is that the larger the expansion amount of the diameter of the stent is, the more the number of times of heat treatment setting is, and vice versa. Preferably, no matter how many times the heat treatment is carried out on the bracket for shaping, the technological parameters of the last heat treatment for shaping are as follows: the heat treatment temperature is 500-650 deg.C, the heat treatment time is 5-35 min, and the argon flow is 5-20 mL/min.

Wherein, in the process of heat treatment and shaping of each component part, the original air in the heat treatment space is firstly emptied, and then inert gas is filled into the heat treatment space, so that the closed state of the heat treatment space is ensured in the treatment process.

Specifically, the furnace chamber can be vacuumized and then filled with inert gas such as argon for protection during the heat treatment process, and the furnace chamber is kept in a closed state during the whole heat treatment process. Considering that the pressure in the hearth increases after the gas is heated, when the gas is introduced after vacuumizing, the hearth is in a negative pressure state, and the pressure in the hearth is about 1/3-2/3 atmospheric pressures.

Or, in the heat treatment process, inert gas such as argon can be introduced for a period of time, the introduction time is (10-30) min, after the air in the hearth is exhausted, the inert gas is introduced into the hearth while the air is discharged, in order to keep the air in the hearth mainly inert gas and prevent the air from entering, the pressure in the hearth needs to be higher than the atmospheric pressure, and the pressure in the hearth needs to be about 1.2-1.5 atmospheric pressures.

S3, carrying out acid washing and electrochemical polishing treatment on each component;

among them, the acid-washing polishing process aims to remove an oxide film generated on the metal surface during heat treatment.

Specifically, the process comprises the steps of removing oxide scales on the metal surface by using an acid solution, wherein the surface of the bracket is dark silver gray at the moment so as to enable the metal surface to be bright silver white; or in order to achieve the purposes of smoothing the surface of the bracket, reducing the friction force, removing burrs in the laser engraving process and the like; or in order to increase the corrosion resistance of the stent and improve the biocompatibility; or one or more or all of the purposes of changing all the stent reticular struts into a more rounded circular or elliptical section, enhancing the supporting force, reducing the stress concentration and the like. The electrochemical polishing process is needed to remove the dark silver gray metal film on the surface of the metal bracket to form a new bright silver white surface, even a mirror surface.

S4, arranging a developing material on each component;

and S5, assembling and connecting the promoting components to form the complete embolectomy support.

It will be appreciated by those skilled in the art that the invention can be embodied in many other specific forms without departing from the spirit or scope thereof. Although embodiments of the present invention have been described, it is to be understood that the present invention should not be limited to those precise embodiments, and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined by the appended claims.

Claims (10)

1. An embolectomy support is characterized by comprising a radially self-expandable and axially stretchable support body, wherein the support body comprises an outer support and an inner support, the inner support is arranged in the outer support, the outer support is connected with the axially proximal end and the axially distal end of the inner support respectively, and the inner support provides axial supporting force for the outer support; and a first opening for the thrombus or the clot to enter the outer-layer stent is also arranged on the side surface of the outer-layer stent.

2. The embolectomy support of claim 1, wherein the outer layer support is formed by sequentially connecting a plurality of support units, and each support unit is of a structure which is symmetrical up and down, left and right; and the two symmetrical sides of each bracket unit are respectively provided with the first opening, and the area of the first opening part on each bracket unit is 0.8-1.5 times of the area of the non-opening part.

3. The embolectomy support of claim 2, wherein each support unit has the same structure, and two adjacent support units are connected by rotating at an angle of alpha in the circumferential direction; the value range of the alpha angle is 0-90 degrees; the connecting point of the adjacent two bracket units is discontinuous on the same connecting line parallel to the axial direction.

4. The embolectomy support of claim 1, wherein the inner support comprises at least one support section and at least one telescoping section connected to compensate for the overall length of the inner support;

the inner layer bracket comprises a supporting section and a telescopic section, wherein the supporting section is positioned at the near end, and the telescopic section is positioned at the far end; or the inner layer support comprises a plurality of supporting sections, and one telescopic section is arranged between every two adjacent supporting sections.

5. The embolectomy support of claim 4, wherein the telescoping section is a spring tube that is axially telescoping; or the telescopic section is of a cross-shaped structure with the size adjustable along the length direction of the inner-layer bracket; the support section is an expandable network-like structure.

6. The embolectomy stent of claim 1, further comprising a catching structure for catching thrombi or clots escaping from the stent body, the catching structure being attached to the distal end of the stent body and having a second opening at an end thereof facing the stent body;

the catching structure is connected with the far end of the outer bracket;

the catching structure adopts a fusiform network structure; .

7. The embolectomy support of claim 6, wherein the support body is provided with a first development portion; an extension rod is arranged at one end of the catching structure, which is back to the bracket main body, and a second developing part is arranged on the extension rod; the bracket is characterized by further comprising a push rod, the push rod is connected with the near end of the bracket main body, and a third developing part is arranged on the push rod.

8. A method for manufacturing a thrombus removal support, which is used for processing the thrombus removal support disclosed in claims 1-7, and comprises the following steps:

s1, processing each component of the bolt taking bracket independently;

s2, carrying out heat treatment setting on each processed component;

s3, carrying out acid washing and electrochemical polishing treatment on each component;

s4, arranging a developing material on each component;

and S5, assembling and connecting the components to form the complete embolectomy support.

9. The method for manufacturing the embolectomy support of claim 8, wherein the step S1 further comprises: respectively processing each component by adopting laser cutting of a metal structure, laser engraving of the metal structure or weaving of metal wires; each component comprises an outer layer bracket, an inner layer bracket, a fishing structure and a push rod.

10. The method for manufacturing the embolectomy support of claim 8, wherein the step S2 further comprises: the outer layer stent and the catching structure are subjected to heat treatment and shaping together to expand the diameter, the inner layer stent is subjected to heat treatment and shaping alone to expand the diameter, and the expansion amount of the inner layer stent is smaller than that of the outer layer stent;

wherein, the outer layer bracket, the fishing structure and the inner layer bracket are all required to be subjected to heat treatment setting for many times, so that the diameters of the outer layer bracket, the fishing structure and the inner layer bracket are gradually expanded to target values.

Wherein, in the process of heat treatment and shaping of each component part, the original air in the heat treatment space is firstly emptied, and then inert gas is filled into the heat treatment space, so that the closed state of the heat treatment space is ensured in the treatment process.

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