CN107811726B

CN107811726B - Covered stent

Info

Publication number: CN107811726B
Application number: CN201610822910.7A
Authority: CN
Inventors: 刘香东
Original assignee: Lifetech Scientific Shenzhen Co Ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2016-09-13
Filing date: 2016-09-13
Publication date: 2020-09-25
Anticipated expiration: 2036-09-13
Also published as: WO2018049868A1; CN107811726A

Abstract

The invention relates to a covered stent, which comprises a metal stent, a covering film covering the surface of the metal stent and a bonding layer arranged between the covering film and the surface. The tectorial membrane in the tectorial membrane stent is tightly combined with the metal stent through the bonding layer, so that the tectorial membrane can be prevented from falling off.

Description

Covered stent

Technical Field

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

Background

With the continuous development of interventional medical devices and interventional surgical methods, the transcatheter intervention and implantation of various artificial valves and artificial vascular stents have become important methods for treating valvular diseases, hemangiomas and vascular stenosis.

Both artificial valve and artificial blood vessel stents comprise a covered stent, and the covered stent generally comprises a metal stent and inner and outer layers of covered films respectively covering the inner and outer surfaces of the metal stent. The metal stent is prepared from super-elastic metal, is used for self-expanding in vivo into a shape adaptive to a valve or a blood vessel, and plays a supporting role in covering the coating films on the inner surface and the outer surface of the metal stent; the inner and outer covering films are configured to block blood flow from the surface of the stent graft.

In the preparation of the covered stent, the inner-layer covered membrane and the outer-layer covered membrane are subjected to hot-pressing compounding, so that the metal stent is fixedly arranged between the inner-layer covered membrane and the outer-layer covered membrane.

After the covered stent prepared by the method, particularly a prosthetic valve containing the covered stent is implanted into a body, the inner and outer covering membranes and the metal stent are easy to peel off under the scouring of blood flow along with the passage of time, so that the metal stent cannot support the inner and outer covering membranes, and the covered stent cannot block the blood flow.

Disclosure of Invention

In view of the above, there is a need for a stent graft in which a metal stent is tightly combined with a stent graft to reduce the possibility of peeling the metal stent from the stent graft.

The invention provides a covered stent, which comprises a metal stent, a covered membrane covering the surface of the metal stent and a bonding layer arranged between the covered membrane and the surface of the metal stent.

The metal stent can be only covered with an outer-layer coating on the outer surface of the metal stent or only covered with an inner-layer coating on the inner surface of the metal stent; it is also possible to cover both its outer and inner surfaces with a coating. The covering may be a complete covering of the entire surface or a covering of a portion of the surface.

When the metal stent is only covered with the coating film on one surface, the bonding layer is arranged between the coating film and the surface where the coating film is arranged. When the two surfaces of the metal stent are both covered with the covering films, the bonding layer can be arranged between any covering film and the surface where the covering film is positioned, and correspondingly, the covering film which is not coated with the bonding layer can directly cover the surface where the covering film is positioned; or the bonding layer is arranged between each coating and the surface where the coating is arranged.

In one embodiment, the material of the bonding layer is polytetrafluoroethylene or parylene.

In one embodiment, the bonding layer has a thickness of 0.1um to 50 um.

In one embodiment, the stent graft further comprises a transition layer disposed between the metal stent and the bonding layer.

In one embodiment, the material of the transition layer is silicon dioxide or epoxy resin.

In one embodiment, the metal bracket is in a hollow tubular shape, and a plurality of hollows are formed in the side surface of the metal bracket.

In one embodiment, the stent graft is a main body frame of a prosthetic valve or a blood vessel stent.

The film of the covered stent is connected with the metal stent through the bonding layer, and the bonding layer has good bonding force with the metal stent and the bonding layer also has good bonding force with the film, so that the film can be tightly bonded with the metal stent through the bonding layer, and the possibility of peeling the metal stent and the film is reduced.

Drawings

FIG. 1 is a schematic structural view of a stent graft of the present invention.

FIG. 2 is a schematic radial cross-sectional view of the stent graft of FIG. 1.

FIG. 3 is a schematic view of a metallic stent of the stent graft of FIG. 1.

FIG. 4 is an enlarged schematic view of the stent graft of FIG. 2 at A.

FIG. 5 is an enlarged schematic view of an alternative configuration of the stent graft of FIG. 2 at A.

FIG. 6 is a schematic structural view of another stent graft of the present invention.

FIG. 7 is an enlarged schematic view of a portion of the stent graft of FIG. 6.

FIG. 8 is a schematic view of a stent graft applied to a heart valve.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 and 2, the stent graft 100 of the present invention is a hollow tubular structure, and includes a metal stent 10, an inner-layer coating 20 covering an inner surface of the metal stent 10, and an outer-layer coating 30 covering an outer surface of the metal stent 10. The metal stent 10 is a support main body of the covered stent 100 and is used for enabling the covered stent 100 to expand and cling to the wall of a human body lumen after being implanted into a body; the inner and

outer cover films

20, 30 serve to form a side-sealed lumen for the stent graft 100, allowing blood flow only through the lumen of the stent graft 100 without leaking out of the sides of the stent graft 100.

The stent graft 100 in this embodiment is the main frame of the prosthetic valve, and the prosthetic valve shown in fig. 8 is formed after at least two closable leaflets 60 are disposed in the lumen of the stent graft 100. The artificial valve can be implanted into a damaged valve of a human body through a catheter after being radially compressed to replace the damaged valve, so that the physiological function of the damaged valve is realized. It will be appreciated that the stent graft 100 may also be other medical devices or portions of medical devices that are implanted in the human body, for example, the stent graft 100 may also be a vascular stent for the treatment of hemangiomas.

Referring to fig. 3, the metal bracket 10 is in a hollow tubular shape, and the metal bracket 10 is an integral structure. The "integral structure" in the present invention means that the metal stent 10 is formed by laser cutting and heat setting a metal tube, or the metal stent 10 is formed by fixedly connecting a plurality of elements, for example, the metal stent 10 is formed by welding two elements. The side surface of the metal support 10 is provided with a plurality of hollows 101, so that the side surface of the metal support 10 is in a hollow net shape.

The metal stent 10 is made of a super-elastic or shape memory metal material, such as nitinol, nickel titanium cobalt, nickel titanium or an alloy thereof. In the invention, the metal stent 10 is formed by cutting a nickel titanium tube, the outer diameter of the nickel titanium tube is preferably 5mm-12mm, and the wall thickness of the nickel titanium tube is preferably 0.2mm-0.6 mm. Firstly, cutting the plurality of hollows out on the nickel-titanium tube by using laser; then, the cut nitinol tube is expanded to a diameter suitable for a damaged valve of a human body under a heat treatment condition to obtain the metal stent 10, and in the present invention, the nitinol tube is preferably expanded to 25mm to 35 mm. It is understood that the metal stent 10 may also be woven from nickel titanium wire.

It is understood that the metal support 10 may also be composed of a plurality of separate elements, and the metal support 10 is not an integral structure, for example, the metal support 10 may be composed of a plurality of separate metal rings, and the axes of the plurality of separate metal rings are welded together to combine the plurality of separate metal rings to form the hollow tubular metal support 10, and in this case, each metal ring may include the hollow, or each two adjacent metal rings may cooperate to form the hollow.

Referring to FIG. 4 in conjunction with FIG. 2, the stent graft 100 further includes an adhesive layer 40 covering the inner and outer surfaces of the metal stent 10. The adhesive layer 40 can be prepared by various methods, such as coating or spraying a polymer adhesive on the inner and outer surfaces of the metal stent 10, or sputtering particles on the inner and outer surfaces of the metal stent 10, or depositing the particles on the inner and outer surfaces of the metal stent 10 by a vapor deposition method. The bonding force between the bonding layer 40 and the surface of the metal stent 10, and between the bonding layer 40 and the inner layer coating 20 or the outer layer coating 30 may be a mechanical bonding force, or a chemical bonding force generated by a chemical reaction between the bonding layer 40 and the inner layer coating 20 or the outer layer coating 30, for example, when the bonding layer 40 is an epoxy resin or an acrylic resin bonding agent, the epoxy resin or the acrylic resin has a chemical bonding force with the inner and outer surfaces of the metal stent 40, and with the inner layer coating 20 and the outer layer coating 30. In the present invention, the material of the adhesive layer 40 is preferably polytetrafluoroethylene or parylene.

The inner-layer film 20 covers the inner surface of the metal support 10 containing the bonding layer 40, the outer-layer film 30 covers the outer surface of the metal support 10 containing the bonding layer 40, the inner-layer film 20 and the outer-layer film 30 are directly connected at the hollow part 101 through hot-pressing composite treatment, and the inner-layer film 20 and the outer-layer film 30 are respectively connected with the metal support 10 through the bonding layer 40.

The materials of the inner layer covering film 20 and the outer layer covering film 30 can be thermoplastic polymer materials, in the invention, the materials of the inner layer covering film 20 and the outer layer covering film 30 are preferably ePTFE (expanded polytetrafluoroethylene), and the inner layer covering film 20 and the outer layer covering film 30 are respectively formed by overlapping multiple ePTFE single-layer films. In the stent graft 100, the inner and outer layer

tectorial membranes

20 and 30 are connected with the metal stent 10 through the bonding layer 40, and the bonding layer 40 and the metal stent 10 have good bonding force, and the bonding layer 40 and the inner and outer layer

tectorial membranes

20 and 30 also have good bonding force, so that the inner and outer layer

tectorial membranes

20 and 30 are tightly bonded with the metal stent 10 through the bonding layer 40, the possibility of stripping the metal stent 10 and the inner and outer layer

tectorial membranes

20 and 30 is reduced, particularly for a prosthetic valve, in the process of opening and closing the valve leaflets, the inner layer tectorial membrane 20 can resist the impact of blood flow, and can avoid falling off from the surface of the metal stent 10; moreover, the bonding layer 40 is coated on the inner and outer surfaces of the metal stent 10, so that the possibility that the metal stent 10 releases metal ions is reduced, the possibility that surface oxide layer particles of the metal stent 10 fall off is also reduced, and the safety of the covered stent 100 after being implanted into a body is ensured.

In the present invention, the thickness of the adhesive layer 40 is preferably 0.1um to 50um, and within the thickness range, the adhesive layer 40 has good bonding force with the metal stent 10 and the inner and

outer layer stents

20, 30, and does not affect the radial compression dimension of the stent graft 100. When the thickness of the adhesive layer 40 is less than 0.1um, the surface of the adhesive layer 40 is prone to generate undesirable defects such as pinholes, etc., so that the bonding force between the adhesive layer 40 and the metal stent 10 or the bonding force between the adhesive layer 40 and the inner and outer layer

tectorial membranes

20, 30 is small, and the inner and outer layer

tectorial membranes

20, 30 may still peel off from the metal stent 10 after the tectorial stent 100 is implanted into the body; when the thickness of the adhesive layer 40 is greater than 50um, the radial compression dimension of the stent graft 100 is significantly increased, so that the stent graft 100 cannot be loaded into a delivery catheter with a smaller inner diameter after being radially compressed, and cannot be implanted into the body through the delivery catheter with a smaller inner diameter, and when the thickness of the adhesive layer 40 is greater than 50um, the ability of the adhesive layer 40 to conform to the deformation of the metal stent 10 is weakened, and therefore, when the metal stent 10 deforms, the adhesive layer 40 is easily peeled off from the metal stent 10.

It is understood that the adhesive layer 40 may not completely cover all of the inner and outer surfaces of the metal stent 10, i.e., the adhesive layer 40 may optionally cover a portion of the surface of the metal stent 10, which may be the entire inner surface of the metal stent 10, or the entire outer surface of the metal stent 10, or a portion of the inner surface and/or a portion of the outer surface of the metal stent 10. For example, in another embodiment, the adhesive layer 40 may only cover the inner surface of the metal stent 10, the inner-layer coating film 20 is tightly combined with the metal stent 10 through the adhesive layer 40, the outer-layer coating film 30 directly covers the outer surface of the metal stent 10 and is thermally compressed with the inner-layer coating film 20 at the hollow 101, when the stent graft 100 is implanted in a body lumen, the outer-layer coating film 30 is tightly pressed against the lumen wall due to the expansion of the metal stent 10, and therefore, even if the outer-layer coating film 30 is not tightly combined with the metal stent 10 through the adhesive layer 40, the possibility of the peeling between the metal stent 10 and the outer-layer coating film 30 is small.

Referring to FIG. 5, in another embodiment of the present invention, the stent graft 100 may further include a transition layer 50. A transition layer 50 is disposed between the metal bracket 10 and the bonding layer 40 for further improving the bonding of the bonding layer 40 to the metal bracket 10. The transition layer 50 is made of a material having a bidirectional bonding capability with the metal support 10 and the bonding layer 40, that is, the transition layer 50 and the metal support 10 have a strong bonding force, and meanwhile, the transition layer 50 and the bonding layer 40 also have a strong bonding force. In the present invention, the material of the transition layer 50 is preferably silica or epoxy resin. In the present invention, the thickness of the transition layer 50 is preferably 1um to 50 um.

Referring to FIGS. 6 and 7, a stent graft 100a according to another embodiment of the present invention has substantially the same structure as the stent graft 100 except that the stent graft 100a includes only an inner coating 20a disposed on an inner surface of a metal stent 10a through an adhesive layer 40a and does not include an outer coating. When the stent graft 100a is implanted into a human body lumen, the inner-layer tectorial membrane 20a of the stent graft 100a prevents blood from seeping out from the side surface of the stent graft 100a, and meanwhile, the outer surface of the metal stent 10a is directly contacted with the wall of the human body lumen, so that the friction force between the stent graft 100a and the wall of the human body lumen is improved, and the stent graft 100a is prevented from moving relative to the human body lumen under the impact force of the blood flow.

It can be understood that, in other embodiments, the covering film combined with the metal stent through the adhesive layer may also be only an outer covering film, at this time, the adhesive layer may cover the entire inner surface and a part of the outer surface of the metal stent, or the adhesive layer may cover the entire inner surface and the entire outer surface of the metal stent, so that not only allergy caused by metal ions released by the metal stent may be more effectively prevented, but also thrombus formed by the surface oxide layer particles of the metal stent falling into blood may be more effectively prevented.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The utility model provides a covered stent, includes the metal support and cover in the tectorial membrane on metal support surface, its characterized in that, the tectorial membrane with be equipped with the tie coat between the metal support surface, covered stent is including cover in the inlayer tectorial membrane of metal support internal surface with cover in the outer tectorial membrane of metal support surface, the inlayer tectorial membrane with outer tectorial membrane is in the fretwork department of metal support connects, the tie coat is located the inlayer tectorial membrane with between the metal support internal surface, and/or, the tie coat is located the metal support surface with between the outer tectorial membrane, the inlayer tectorial membrane reaches outer tectorial membrane is expanded polytetrafluoroethylene, the tie coat in the metal support, the tie coat is polytetrafluoroethylene.

2. The stent graft of claim 1, wherein the tie layer has a thickness of 0.1um to 50 um.

3. The stent graft of claim 1, further comprising a transition layer disposed between the metal stent and the bonding layer.

4. The stent graft of claim 3, wherein the material of the transition layer is silica or epoxy.

5. The stent graft of any one of claims 1-4, wherein the stent graft is a main frame of a prosthetic valve or a vascular stent.