CN114052820A

CN114052820A - Blood vessel support

Info

Publication number: CN114052820A
Application number: CN202111443652.9A
Authority: CN
Inventors: 李峥; 金飞龙; 刘享承; 吴子贤; 赵中
Original assignee: Zhuhai Tongqiao Medical Technology Co ltd
Current assignee: Zhuhai Tongqiao Medical Technology Co ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-02-18
Anticipated expiration: 2041-11-30
Also published as: CN114052820B

Abstract

The invention discloses a vascular stent, which belongs to the technical field of medical appliances, and is formed by weaving braided wires, and along the length direction of the vascular stent, the vascular stent at least comprises a far-end weaving section, a middle weaving section and a near-end weaving section: the flaring structures at the two ends of the blood vessel support provide better blood vessel anchoring effect; the mesh density with two sparse ends reduces the influence on the collateral blood vessels; the closed loop structure of the far-end braided wire improves the safety of the bracket; the knitting silk diameter of the far-end knitting section and the knitting silk diameter of the near-end knitting section are larger, so that the radial supporting force of the bracket is enhanced. The design of the invention can enhance the radial supporting force of the stent and simultaneously give consideration to good implantation stability, safety and integrity of the blood vessel stent.

Description

Blood vessel support

Technical Field

The invention relates to the technical field of medical instruments, in particular to a vascular stent.

Background

Intracranial aneurysms are one of the common hemorrhagic cerebrovascular diseases with a major risk of rupture bleeding with high mortality and disability rates. Intracranial aneurysms rupture, leading to subarachnoid space bleeding, seriously jeopardizing the patient's life health. If subarachnoid hemorrhage occurs, the untreated lethality rate approaches 50%, and the disability rate after treatment is as high as 60%. Hemodynamic disorders are considered to be a major factor in the development, progression and rupture of intracranial aneurysms. Reconstruction of intracranial parent arteries, correction of hemodynamic disorders of parent arteries, is the endpoint target for treatment of intracranial aneurysms.

At present, methods for treating intracranial aneurysms mainly comprise two main types of intravascular interventional therapy and craniotomy clamping therapy. Craniotomy clipping has a very high surgical risk and has been replaced in recent years by safer endovascular interventions. The vascular interventional therapy mainly depends on two types of instruments: a tumor inner turbulent flow device and a tumor neck opening flow guide device. Among them, coil embolization is a typical representation of intratumoral occluders, which rely on intratumoral filling coils to slow the blood flow rate within the tumor. The blood flow guiding device is a representative of a flow guiding device, and the neck of a tumor is blocked by a dense net structure. Compared with the spring coil embolization, the blood flow guiding device has the following advantages: 1. for giant and wide-neck aneurysms, the blood flow guiding device can avoid the mass occupation effect caused by the filling of the spring ring and can also avoid the escape of the spring ring; 2. the blood flow guiding device can promote the repair of the vascular intima at the tumor neck and remodel the blood vessel.

In the patent of US20160361180a1, a double layered stent is disclosed, the outer layer of the stent using thicker wires to provide a large radial support force, and the inner layer of the stent using thinner wires with a denser mesh to provide a blood flow-guiding therapeutic effect. However, the following problems still exist in the design: 1) radial support force and vascular compliance are not compromised: the whole stent has larger radial supporting force due to the outer stent, but the stent is harder, and the vascular compliance is poor under the extremely tortuous cerebrovascular environment; 2) stents do not have good integrity: the mode that ectonexine support passes through mechanical connection chooses some point locations to fix, and ectonexine support has the risk of taking place the dislocation, and the in-process of carrying in the pipe, has great propelling movement resistance, has increased the degree of difficulty of operation.

In the utility model with chinese patent publication No. CN212261624U, the reinforcement of the woven stent is provided, and the laser engraved reinforcement is added on both sides of the stent to enhance the radial supporting force of the stent and improve the stability of the stent in the blood vessel, but the way of adding additional connecting pieces in the axial direction of the stent is similar to the way of adding connecting pieces in the radial direction as provided in the above patent of invention US20160361180a1, and all have the same defects: the support is not good in integrity, so that the stability of the support is not high, the support has large pushing resistance, and the operation difficulty is large.

In the utility model patent of chinese patent publication No. CN214180706U, a mixed stent woven by thick filaments and thin filaments is provided, this design is applicable to the field of treating carotid artery stenosis, and the thick filaments provide big radial support force, and the thin filaments provide fine and dense meshes, are used for preventing vascular plaque from being broken, improve stent security. However, when the thick silk and the thin silk are mixed and woven in the field of intracranial aneurysm treatment, the mesh density at the position of the neck opening of the aneurysm is uneven, the mesh at the weaving position of the thick silk is smaller, the mesh at the weaving position of the thin silk is larger, the blood flow guiding effect is influenced, and the treatment effect is reduced.

In the utility model patent with the chinese patent publication No. CN212382692U, a weaving scheme with different mesh densities at different positions of the stent is provided, the mesh density at the middle part of the stent is dense, so as to ensure the effect of blocking the neck of the tumor, and the mesh density at the two ends of the stent is sparse, so as to avoid the influence on the side branch vessels. However, this design also has several disadvantages: 1) the woven meshes on the two sides of the stent are sparse, so that the radial supporting force of the parts on the two sides of the stent is seriously lost, the two sides of the stent are retracted inwards, and the retracted parts easily cause the blood flow to slow down, induce thrombus and cause the stenosis of blood vessels; 2) the binding between the knitting yarns on the two sides of the support is weakened, the knitting grids on the two sides are easy to be disordered, and the knitting yarns are separated from the original positions, so that the radial supporting force is further deteriorated.

The existing stent obtains larger radial supporting force by depending on an outer layer coated hard stent, but lacks good compliance and integrity of a tortuous vessel; even if the radial supporting force and the vascular compliance are integrated by the mixed weaving mode of thick wires and thin wires, the woven meshes in the middle section of the stent are different in size, the effect of slowing down the blood flow velocity in the tumor cannot be effectively achieved, and the curative effect is influenced; and the scheme of improving the safety of the stent by reducing the grid density on the two sides of the stent can reduce the radial supporting force on the two sides of the stent, cause the two sides of the stent to contract inwards and induce thrombus.

In summary, the current blood flow guiding device for treating intracranial aneurysm cannot well take into account the radial supporting force and other key performances. In view of this, the present application is proposed.

Disclosure of Invention

In order to solve the technical problem in at least one aspect of the background art, the present invention provides a vascular stent, which can effectively solve at least one technical problem.

The invention provides a blood vessel support which is formed by weaving braided wires, and along the length direction of the blood vessel support, the blood vessel support at least comprises a far-end weaving section, a middle weaving section and a near-end weaving section:

the mesh size of the intermediate braided section is smaller than the mesh size of the distal braided section; and/or the mesh size of the intermediate braided section is smaller than the mesh size of the proximal braided section;

the distal braid segment flares outwardly away from a side of the intermediate braid segment; and/or, the proximal braided section flares outwardly away from a side of the intermediate braided section;

the side of the far-end weaving section far away from the middle weaving section forms a closed loop;

the filament diameter of the knitting filaments at the far-end knitting section is not less than D1; the diameter of the knitting silk positioned in the middle knitting section is not more than D2; the filament diameter of the knitting filaments at the proximal knitting section is not less than D3; wherein D2< D1, and D2< D3.

Preferably, D2/D1 is 0.8-0.95; D2/D3 is 0.8-0.95.

A first transition section is arranged between the far-end weaving section and the middle weaving section, and the filament diameter of the weaving filament at the first transition section is gradually reduced from D1 to D2; and/or the presence of a gas in the gas,

a second transition section is arranged between the near-end weaving section and the middle weaving section, and the filament diameter of the weaving filament at the second transition section is gradually reduced from D3 to D2.

Preferably, the rate of change of the filament diameter of the braided filaments at the first transition section is constant; and/or the rate of change of the filament diameter of the braided filaments at the second transition section is constant.

Preferably, the braided filaments at the first transition section change at a rate of 0.01mm reduction in filament diameter per 10mm length; and/or the braided filaments in the second transition section change at a rate of 0.01mm reduction in filament diameter per 10mm length.

Preferably, the diameter of the knitting filaments at the intermediate knitting section is constant.

Preferably, the wire diameter of the braided wire at the distal braided section is constant; and/or the filament diameter of the braided filaments at the proximal braided section is constant.

Preferably, the number of meshes per inch of the intermediate braided section PPI is 100-400.

Preferably, a side of the distal weaving section, which is far away from the middle weaving section, is provided with a plurality of first developing materials which are arranged at intervals around the circumference of the blood vessel stent; and/or one side of the near-end weaving section, which is far away from the middle weaving section, is provided with a plurality of second developing materials which are arranged at intervals around the circumference of the vascular stent.

Preferably, the first developing material and the second developing material are both developing rings; the second developing material is bonded with the weaving silk through glue; the first developing material is pressed on the knitting silk.

The beneficial effects brought by one aspect of the invention are as follows:

the diameter of the knitting silk of the middle knitting section is smaller, and the knitting silk of the far-end knitting section and the knitting silk of the near-end knitting section are larger. The design of the invention can well integrate the physical properties required by the vascular stent at the far end, the near end and the middle.

Drawings

FIG. 1 is a schematic structural diagram of a simulated intravascular stent woven by thick wires according to the present invention;

FIG. 2 is a schematic structural diagram of a simulated intravascular stent woven with filaments according to the present disclosure;

FIG. 3 is an axial view of the present disclosure;

FIG. 4 is a front view of the present disclosure;

FIG. 5 is a schematic structural view of a braided wire according to the present disclosure;

FIG. 6 is an enlarged schematic view of a mesh according to the present disclosure;

FIG. 7 discloses a schematic structural diagram simulating the intravascular use of the vascular stent of the present invention;

fig. 8 discloses a simulation of the release of the vascular stent of the present invention in a blood vessel.

Detailed Description

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments in the present application may be combined with each other; the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left" and "right", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the positions or elements referred to must have specific orientations, be constructed in specific orientations, and be operated, and thus are not to be construed as limitations of the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Application overview:

with reference to fig. 1, applicants simulated the analysis of a thick wire braided vascular stent:

the stent is woven from woven filaments of uniform diameter and has a larger filament diameter, in other words, the stent is "stiff". The whole blood vessel stent has larger radial supporting strength and bending resistance strength, and the self-expansion of the blood vessel stent can be successful. However, in extremely tortuous vessels, the vascular stent tends to change the course of the vessel itself and to create a cavity in the curved portion.

With reference to fig. 2, applicants simulated the analysis of a stent woven with filaments:

the stent body is woven from woven filaments of uniform diameter and having a smaller filament diameter, in other words, the stent is "soft". At the moment, the blood vessel stent can well fit extremely tortuous blood vessels. However, the smaller wire diameter leads to smaller radial supporting force, and such a stent is easy to cause that the stent cannot successfully complete self-expansion at some parts, so that external force such as a balloon is needed to assist the expansion, and the abnormality frequently occurs at the near end and the far end of the stent and appears as "necking" at the two ends of the stent.

The technical solution of the present application is further explained below.

Referring to fig. 3-7, the vessel stent 1 proposed by the present invention is formed by weaving braided filaments S, and along the length direction of the vessel stent 1, the vessel stent 1 at least comprises a distal braided section 10, a middle braided section 11, and a proximal braided section 12:

the diameter of the knitting yarn S at the distal knitting stage 10 is not smaller than D1; the diameter of the knitting yarn S at the middle knitting section 11 is not more than D2; the diameter of the knitting yarn S at the proximal knitting section 12 is not smaller than D3; wherein D2< D1, and D2< D3.

The diameter of the knitting yarn S in the middle knitting section 11 is small, and the knitting yarn S in the distal knitting section 10 and the knitting yarn S in the proximal knitting section 12 are large.

The design of the embodiment can well integrate the physical properties required by the blood vessel stent at the far end, the near end and the middle.

In the extremely tortuous blood vessel environment, the middle braided section 11 does not need a large radial support strength and bending strength at the blood vessel bending portion, but needs a small bending strength and good smoothness, so that the wire diameter of the middle braided section 11 is desirably small. The middle weaving section 11 has smaller wire diameter, and the weaving grid can be more easily attached to the tortuous inner wall of the blood vessel through extension, so that the blood vessel stent has better compliance of the tortuous blood vessel, can treat aneurysm at the part of the tortuous blood vessel, and simultaneously provides better adherence performance.

With reference to fig. 7, the middle braided section 11 is attached to the inner wall of the blood vessel to close the neck of the aneurysm, thereby gradually reducing the blood entering and reducing the contact between the blood and the aneurysm.

At the two ends of the blood vessel stent, larger radial support strength is needed to prevent the two sides of the blood vessel stent from necking down, so that the blood vessel stent is successfully self-expanded in the releasing process to open the blood vessel stent, and the wire diameters of the far-end weaving section 10 and the near-end weaving section 12 are ideal to be larger. The far-end weaving section 10 and the near-end weaving section 12 have larger wire diameters, so that the radial supporting force of the near end and the far end of the intravascular stent is increased, the intravascular stent can be effectively prevented from postoperative displacement caused by the contraction and relaxation of blood vessels and the impact of blood flow, and the stability of the intravascular stent is enhanced.

As a further refinement of the above example, in one embodiment, D2/D1 is 0.8-0.95; D2/D3 is 0.8-0.95.

As a further improvement of the above embodiment, in one embodiment, a first transition section 13 is provided between the distal weaving section 10 and the middle weaving section 11, and the diameter of the weaving filament S at the first transition section 13 is gradually reduced from D1 to D2.

A second transition section 14 is arranged between the proximal weaving section 12 and the middle weaving section 11, and the wire diameter of the weaving wire S at the second transition section 14 is gradually reduced from D3 to D2.

Referring to fig. 5, the present embodiment may be woven with variable diameter weaving wires S to form a vascular stent.

The first transition section 13 and the second transition section 14 are arranged. The diameter of the braided wire S gradually decreases from both ends to the middle along the length direction of the stent 1.

As a further improvement of the above example, in one embodiment, the rate of change of the filament diameter of the knitting filaments S located at the first transition section 13 is constant; the rate of change of the wire diameter of the knitting wires S at the second transition section 14 is constant. As a further improvement of the above example, in one embodiment the braided filaments S at the first transition section 13 change at a rate of 0.01mm reduction in filament diameter per 10mm length; the braided filaments S at the second transition section 14 change at a rate of 0.01mm reduction in filament diameter per 10mm length.

The first transition section 13 and the second transition section 14 are transition parts with the wire diameters being gradually reduced, and the wire diameters of the first transition section 13 and the second transition section 14 are required to be changed at a constant and uniform rate. The transmission balance of the internal stress of the blood vessel support 1 on the braided wire S is ensured, and the blood vessel support 1 is prevented from being twisted due to the sudden change of the wire diameter.

As a further improvement of the above-described embodiment, in one embodiment, the diameter of the knitting filaments S located in the intermediate knitting section 11 is constant. The silk diameter of the middle weaving section 11 is constant and uniform, so that the middle weaving section 11 has uniform and stable grid density, the blood flow velocity in aneurysm can be effectively reduced, and the treatment effect is ensured.

As a further improvement of the above example, in one embodiment, the diameter of the knitting filaments S at the distal knitting section 10 is constant; the diameter of the knitting filaments S at the proximal knitting section 12 is constant.

As a further improvement of the above embodiment, in one embodiment, the braided wire S is one or more of nickel-titanium alloy, stainless steel, cobalt-chromium alloy, nitinol, and nickel-cobalt alloy.

As a further improvement of the above embodiment, in one embodiment, the mesh size of the intermediate braided section 11 is smaller than the mesh size of the distal braided section 10; the mesh size of the intermediate woven stage 11 is smaller than the mesh size of the proximal woven stage 12.

Referring to fig. 7, the stent is simulated to be placed in a parent artery, and the distal woven segment 10 and the proximal woven segment 12 tend to cover the side branch vessels on both sides of the intracranial aneurysm. Therefore, in order to improve the influence of the variable diameter of the weaving wire S of the blood vessel stent on the collateral blood vessel, the mesh size of the blood vessel stent is designed to be changed. Therefore, the large meshes at the two ends of the blood vessel support can allow blood flow to pass through, and side branch blood near the intracranial aneurysm is prevented from being sealed. The intermediate woven segment 11 has a uniform, finer lattice density, resulting in effective closure of the aneurysm neck.

As a further improvement of the above embodiment, in one implementation, the number of meshes per inch of the intermediate braided section PPI is 100-.

The blood flow guiding device and the blood flow bracket have various specifications with different diameters so as to adapt to the blood vessel environments with different thicknesses. Along with the increase of the diameter of the blood vessel stent, the number of the weaving strands of the variable diameter weaving wires S forming the blood vessel stent is increased, so that the mesh density which is reduced along with the increase of the diameter of the blood vessel stent is compensated.

The mesh of the blood vessel stent is rhombic, and the side length of the mesh of the middle weaving section 11 can be 0.05-0.5 mm; the side length of the mesh of the far-end weaving section 10 can be 1-10 mm; the mesh side length of the proximal weaving section 12 may be 1-10 mm. The mesh size may be selected as appropriate depending on the stent size.

The length of the long diagonal of the mesh is b, the length of the wide diagonal is a, wherein b/a is 2.5-3.5.

For example, the diameter specification is

The number of braided wires S of the stent of (1) is 72, and the lattice number per unit inch of the intermediate braided section 11 PPI is 155, under the control of these conditions, as shown in fig. 6, the ratio of b/a of the stent of this specification is controlled to be in the range of 2.5-3.5.

Therefore, by adjusting the number of weaving strands of the variable-diameter weaving wires S and the side length of the meshes, the middle weaving section 11 of the intravascular stent with different diameters can be better controlled to have more uniform and stable mesh density, and therefore the blood flow guiding device with each specification can have stable treatment effect.

As a further improvement of the above example, in one embodiment, the side of the distal braided section 10 remote from the intermediate braided section 11 flares outwardly; the side of the proximal braided section 12 remote from the intermediate braided section 11 flares outwardly.

With reference to fig. 8, by expanding the two ends of the stent outward, the anchoring effect of the thick-wire portions at the two ends of the stent can be improved, the horn-shaped structure of the wide mouth at the distal end of the stent is attached to the wall in the blood vessel, and the dotted line in fig. 8 is the distal end flaring structure, so that the distal end of the stent can bear larger stress F in the blood vessel, the friction between the distal end of the stent and the blood vessel is improved, and the anchoring effect is realized. Meanwhile, the risk of necking at two ends of the blood vessel support can be effectively reduced, and the blood vessel support is prevented from shifting due to the watermelon seed effect.

As a further improvement of the above embodiment, in one embodiment, a side of the distal woven segment 10 away from the middle woven segment 11 is mounted with a plurality of first visualization materials 15, and the plurality of first visualization materials 15 are arranged at intervals around the circumference of the stent; the side of the proximal weaving section 12 far away from the middle weaving section 11 is provided with a plurality of second developing materials 16, and the plurality of second developing materials 16 are arranged around the blood vessel support at intervals in the circumferential direction.

As a further improvement of the above example, in one embodiment, the first developing material 15 and the second developing material 16 are both developing rings. As a further improvement of the above embodiment, in one embodiment, the second developing material 16 is bonded to the woven filaments S by glue; the first developing material 15 is pressed against the knitting yarn S.

The first developing material 15 and the second developing material 16 are arranged, so that the position of the blood vessel stent in the blood vessel is better determined, and the safety and the stability of the operation of a doctor in the operation are improved.

As a further improvement of the above described embodiment, in one embodiment the side of the distal weaving section 10 remote from the intermediate weaving section 11 forms a closed loop.

The braided wire S starts at the proximal braiding section 12, is wound several turns around a mandrel, and is looped back in the opposite direction at the distal braiding section 10 to form a closed loop structure, and finally returns to the proximal braiding section 12. The mandrel is used for weaving the weaving silk S to form the blood vessel stent.

In use, referring to fig. 8, the blood vessel stent 1 is guided into the access catheter preset in the blood vessel, then the conveying wire is pushed to drive the blood vessel stent to move in the catheter, and finally the blood vessel stent is pushed out of the catheter at a proper position to be released.

Referring to fig. 8, due to the thick diameter of the distal braided section 10, the hard thick wire is easy to stab the inner wall of the blood vessel during the release process in the blood vessel after the blood vessel stent is pushed out of the catheter. Therefore, the structural design of the closed loop can avoid the direct contact of the tip of the weaving wire S with the inner wall of the blood vessel, and effectively avoid the negative influence caused by the reducing design of the weaving wire S. Meanwhile, when a doctor pushes the vascular stent to anchor the far end of the vascular stent to a blood vessel, the far end anchoring position of the stent is often required to be adjusted, and the far end closed loop structure can improve the operation safety.

In summary, compared with the conventional vascular stent, the vascular stent 1 of the present embodiment has good radial support force and compliance of tortuous vessels while maintaining the integrity of the vascular stent; after the wire diameters of the two ends of the blood vessel support 1 are thickened, the blood vessel support 1 can be maintained to have good implantation stability and safety by setting a closed loop, changing the grid density and flaring the two ends of the blood vessel support 1.

By searching, no similar technique was found. The technical scheme of the embodiment belongs to international initiatives, has good radial supporting force and tortuosity compliance, and has good clinical application prospect.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A vascular stent formed by weaving braided filaments, the vascular stent comprising at least a distal braided section, an intermediate braided section, and a proximal braided section along a length of the vascular stent:

2. The vascular stent of claim 1, wherein D2/D1 is 0.8-0.95; D2/D3 is 0.8-0.95.

3. The blood vessel support of claim 1 or 2, wherein a first transition section is arranged between the distal weaving section and the middle weaving section, and the diameter of the weaving wire at the first transition section is gradually reduced from D1 to D2; and/or the presence of a gas in the gas,

4. A vascular stent as in claim 3, wherein the rate of change of the filament diameters of the braided filaments at the first transition section is constant; and/or the rate of change of the filament diameter of the braided filaments at the second transition section is constant.

5. The vascular stent of claim 4, wherein the braided filaments at the first transition section change at a rate of 0.01mm decrease in filament diameter per 10mm length; and/or the braided filaments in the second transition section change at a rate of 0.01mm reduction in filament diameter per 10mm length.

6. A vascular stent as in claim 1 or 2, wherein the filaments of the braided wires at the intermediate braided section have a constant diameter.

7. A vascular stent as in claim 1 or 2, wherein the wire diameter of the braided wires at the distal braided section is constant; and/or the filament diameter of the braided filaments at the proximal braided section is constant.

8. The vascular stent of claim 1, wherein the middle braided section has a lattice number per inch PPI of 100-400.

9. The vascular stent of claim 1, wherein a side of the distal woven section remote from the intermediate woven section is fitted with a plurality of first visualization materials, the plurality of first visualization materials being spaced circumferentially around the vascular stent; and/or one side of the near-end weaving section, which is far away from the middle weaving section, is provided with a plurality of second developing materials which are arranged at intervals around the circumference of the vascular stent.

10. The vascular stent of claim 9, wherein the first visualization material and the second visualization material are both visualization rings; the second developing material is bonded with the weaving silk through glue; the first developing material is pressed on the knitting silk.