CN112998907A

CN112998907A - Covered stent

Info

Publication number: CN112998907A
Application number: CN201911329021.7A
Authority: CN
Inventors: 刘彩萍
Original assignee: Shenzhen Xianjian Changtong Medical Co ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2021-06-22
Anticipated expiration: 2039-12-20
Also published as: CN112998907B

Abstract

The invention discloses a covered stent, which comprises a bare stent and a covered membrane connected to the bare stent, wherein an extrusion piece is arranged on the covered stent, the extrusion piece is provided with a flexible part, the bending strength of the flexible part is smaller than that of the rest parts of the extrusion piece, and after the covered stent is released, at least one part of the extrusion piece is positioned in the end part area of the covered membrane and drives the covered membrane in the end part area to move outwards. The invention has the beneficial effects that: this application drives the tectorial membrane in the tip region through the extruded article and moves to the outside, can improve the adherence of the tectorial membrane in this tip region, avoids forming the clearance between tip and the blood vessel inner wall of its tectorial membrane after the tectorial membrane support implants the blood vessel.

Description

Covered stent

Technical Field

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

Background

In more than ten years, aorta covered stent endoluminal isolation has been widely applied to lesions such as thoracic and abdominal aortic aneurysms and arterial dissections, has definite curative effect, small wound, quick recovery and few complications, and becomes a first-line treatment method. During operation, under the X-ray fluoroscopy monitoring, the covered stent is conveyed to the pathological change position through the corresponding conveying system, the covered stent isolates blood flow from the pathological change position, and the influence of blood pressure on the pathological change position is eliminated, so that the purpose of curing is achieved.

After the stent graft is implanted, the stent graft is fixed in a blood vessel by using the radial supporting force of the stent graft, so that the diameter of the stent graft is larger than the inner diameter of the blood vessel to resist the impact of blood flow in order to avoid the displacement of the stent graft under the impact of the blood flow, and the stent graft is always in a compressed state in the blood vessel. As shown in fig. 1 and 2, when the stent graft 100a is implanted into a blood vessel 200a, the stent graft 101a at the end of the stent graft 100a is bent inward in a compressed state to form a gap 300a between the stent graft 101a and the inner wall of the blood vessel 200a, and after blood flows into the gap 300a, thrombus is easily formed and the body of a patient is injured. Meanwhile, when blood flows into the gap 300a, the impact surface of the blood flow on the stent graft 100a increases, which increases the impact force of the blood flow on the stent graft 100a, and further causes the stent graft 100a to shift, resulting in treatment failure.

Disclosure of Invention

The present invention is directed to provide a stent graft, which addresses the above-mentioned shortcomings of the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the utility model provides a covered stent, includes naked support, and connects tectorial membrane on the naked support, be provided with the extruded article on the covered stent, the extruded article has flexible portion, the bending strength of flexible portion is less than the bending strength of the other positions of extruded article, after the covered stent release, at least some of extruded article are located the tip region of tectorial membrane, and drive tectorial membrane in the tip region moves to the outside.

In the covered stent, the extrusion piece is positioned on the inner wall of the covered stent, two ends of the extrusion piece are respectively fixed on the bare stent, and the extrusion piece can move relative to the covering membrane.

In the stent graft of the present invention, the extrusion comprises a connecting section and an extrusion section which are connected, the connecting section is fixedly connected with the bare stent, at least one part of the extrusion section is positioned in the end area, and the flexible part is positioned on the extrusion section.

In the covered stent, the bare stent comprises a plurality of circles of wavy rings, each wavy ring comprises a plurality of wave crests, a plurality of wave troughs and a plurality of connecting rods which are respectively connected with the adjacent wave crests and the adjacent wave troughs;

the extrusion piece is arranged between two adjacent wave crests of the wave-shaped ring, and two ends of the extrusion piece are respectively fixed on two adjacent connecting rods.

In the stent graft of the present invention, the extrusion is located in the same annular plane as the bare stent.

In the stent graft of the present invention, the extrusion is of an annular configuration.

In the stent graft of the present invention, the extrusion is fixed to the bare stent.

In the covered stent, the diameter of the circumcircle of the cross section of the extrusion part is 0.1 mm-0.3 mm.

In the covered stent, a limiting piece is further arranged on the covered stent, a limiting channel is arranged in the limiting piece, and the extrusion piece can movably penetrate through the limiting channel.

In the stent graft of the present invention, the distance between the limiting element and the end of the stent graft in the axial direction is 0.5mm to 2mm, and the width of the limiting element in the axial direction is 0.11mm to 1.5 mm.

In conclusion, the stent graft provided by the invention has the following beneficial effects: this application drives the tectorial membrane in the tip region through the extruded article and moves to the outside, can improve the adherence of the tectorial membrane in this tip region, avoids forming the clearance between tip and the blood vessel inner wall of its tectorial membrane after the tectorial membrane support implants the blood vessel. And, through set up the flexible portion on the extruded piece, this flexible portion has less bending strength relative to the rest position of extruded piece, when along radial extrusion tectorial membrane support, the extruded piece is the bending deformation more easily in flexible portion department, makes the extruded piece can be by radial compression, makes things convenient for the whole sheath of going into of tectorial membrane support.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic view of a prior art stent graft implanted within a vessel;

FIG. 2 is a cross-sectional view of an end of the stent graft of FIG. 1;

FIG. 3 is a schematic view of a stent graft provided in accordance with one embodiment of the present invention;

FIG. 4 is an enlarged view of section A of the stent graft shown in FIG. 3;

FIG. 5 is a schematic view of a flexible portion of an extrusion of the stent graft of FIG. 3 bent distally;

FIG. 6 is a schematic view of the stent graft of FIG. 3 after being radially compressed;

FIG. 7 is a schematic view of a flexible portion of an extrusion of the stent graft of FIG. 3 bent proximally;

FIG. 8 is a schematic view of a flexible portion of an extrusion of the stent graft of FIG. 7;

FIG. 9 is a schematic view of an extrusion of the stent graft of FIG. 5;

FIG. 10 is a schematic view of a stent graft provided in accordance with a second embodiment of the present invention;

FIG. 11 is a schematic view of the stent graft of FIG. 10 after being radially compressed.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the field of interventional medicine, it is commonly defined that a stent graft is proximal at the end proximal to the heart and distal at the end distal to the heart after release.

Referring to FIG. 3, one embodiment of the present application provides a stent graft 100, which includes a bare stent 101 and a stent graft 102 connected to the bare stent 101. The stent graft 100 has a hollow lumen structure, and the lumen of the stent graft 100 constitutes a blood flow passage.

The bare stent 101 is made of a material with good biocompatibility, such as nickel titanium, stainless steel, and the like. The covering membrane 102 is made of a polymer material with good biocompatibility, such as PTFE, FEP, PET, and the like. The bare stent 101 comprises a plurality of circles of wavy rings 1011, each circle of wavy ring 1011 comprises a plurality of peaks 1011a, a plurality of valleys 1011b and a plurality of connecting rods 1011c respectively connecting the adjacent peaks 1011a and valleys 1011b, and the plurality of circles of wavy rings 1011 are arranged in sequence from the proximal end to the distal end, preferably in parallel at intervals. The wavy rings 1011 are closed cylindrical structures, and multiple circles of the wavy rings 1011 can have the same or similar wavy shapes, and it is understood that the specific structure of the wavy rings 1011 is not limited in this embodiment, the wavy rings 1011 can have the wavy shapes set as required, and the number of the wavy shapes and the heights of the wavy shapes in each circle of the wavy rings 1011 can be set as required.

Referring to FIGS. 3 and 4, the inner wall of the stent graft 100 is provided with the extrusion 11, and the extrusion 11 has a flexible portion 110, and the flexible portion 110 has a small bending strength with respect to the rest of the extrusion 11, and the extrusion 11 is easily bent and deformed at the flexible portion 110 when the stent graft 100 is radially compressed. After the stent graft 100 is released, at least a portion of the extrusion 11 is located in the end region of the stent graft 102 and presses the stent graft 102 outwardly in the end region, i.e., the extrusion 11 moves the stent graft 102 outwardly in the end region.

The "end region of the coating 102" refers to a region of the coating 102 at an axial distance of 0 to 3.5mm from the end of the coating 102; "outwardly" refers to a direction away from the centerline of the stent graft.

This application outwards extrudes the tectorial membrane in the tip region of tectorial membrane 102 through extruded piece 11, can improve the adherence of tectorial membrane 102 in this tip region, makes the tectorial membrane in the tip region of tectorial membrane 102 completely attached on the blood vessel inner wall, avoids forming the clearance between the tip of its tectorial membrane 102 and the blood vessel inner wall after tectorial membrane support 100 implants the blood vessel. Also, by providing the flexible portion 110 on the extrusion 11, the flexible portion 110 has less bending strength relative to the remainder of the extrusion 11, and when the stent graft 100 is radially compressed, the extrusion 11 is more easily bent at the flexible portion 110, allowing the extrusion 11 to be radially compressed, facilitating sheathing of the entire stent graft 100.

Referring to fig. 4 and 5, an extruded member 11 is disposed between two adjacent peaks 1011a of the corrugated ring 1011, and both ends of the extruded member 11 are respectively fixed to two adjacent connecting rods 1011 c. The extrusion member 11 is movably connected with the film 102, so that relative movement can be generated between the extrusion member 11 and the film 102. The flexible portion 110 is located in a middle region of the extrusion 11, and the flexible portion 110 is a U-shaped structure that bends toward the distal end of the stent graft 100. referring to FIG. 6, when the stent graft 100 is extruded in a radial direction, the flexible portion 110 bends toward the distal end of the stent graft 100. It should be noted that the "central region of the pressing member 11" herein means a region located between both end portions of the pressing member 11 except for the both end portions. Preferably, the flexible portion 110 is located in the middle of the pressing member 11 so that the pressing member 11 is uniformly compressed.

Because the two ends of the extrusion piece 11 are respectively fixed on the bare stent 101, when the covered stent 100 is unfolded, the bare stent 101 can provide a force towards the direction of the blood vessel wall for the extrusion piece 11, which is beneficial for the extrusion piece 11 to extrude the covering film in the end area of the covering film 102 outwards, so that the covering film in the end area is completely attached to the inner wall of the blood vessel.

In order to enable the extrusion part 11 to better extrude the wrinkles on the film 102 outwards, the extrusion part 11 is arranged between two adjacent wave crests 1011a of the wave-shaped ring 1011, and the extrusion part 11 is integrally positioned in the end area of the film 102. When the stent graft 100 is released, the extrusion 11 is fully engaged with the graft 102, i.e., the extrusion 11 is on the same annular face as the undulating ring 1011.

It will be appreciated by those skilled in the art that the extrusion member 11 of the present embodiment is merely exemplary and not intended to limit the present invention, and in other embodiments, the extrusion member 11 may span one or more wave structures of the wave ring 1011 such that both ends of the extrusion member 11 are respectively fixed to the two spaced connecting rods 1011c, that is, as long as both ends of the extrusion member 11 are respectively fixed to the bare bracket 101. Also, the present embodiment does not limit the number of the pressing members 11 connected to the corrugated ring 1011, and in other embodiments, the pressing members 11 may include one, two or more as necessary.

It is understood that the present embodiment does not limit the specific structure of the flexible portion 110, and in other embodiments, the flexible portion 110 may have other structures. For example, in the embodiment illustrated in FIGS. 7 and 8, the flexible portion 110 is a U-shaped structure that bends toward the proximal end of the stent graft 100, and when the stent graft 100 is radially compressed, the flexible portion 110 bends toward the proximal end of the stent graft 100. Alternatively, in other embodiments, the flexible portion 110 may also be a groove structure, a hole structure, a cut structure, or the like provided on the pressing member 11, as long as the flexible portion 110 is made to have a small bending strength with respect to the rest of the pressing member 11.

The extrusion member 11 is made of a material having good biocompatibility and elasticity, such as nickel titanium, stainless steel, etc. Since the extrusion member 11 needs to extrude the covering film 102 outwards to make the covering film 102 completely attached to the blood vessel wall, if the wire diameter of the extrusion member 11 is too small, the resilience of the extrusion member 11 is poor and is not enough to provide enough radial supporting force to extrude the folds; if the wire diameter of the extrusion 11 is too large, the overall compressed volume of the stent graft 100 may increase, which may affect sheathing. Therefore, the diameter of the circumcircle of the cross section of the extrusion member 11 is preferably 0.1mm to 0.3mm, so that the extrusion member 11 can better extrude the coating film 102 outwards, and the adherence of the coating film 102 is improved.

Referring to fig. 9, the extrusion member 11 includes a connecting section 111 and an extrusion section 112 connected, the connecting section 111 is fixedly connected with the bare stent 101, and at least a portion of the extrusion section 112 is located in an end region of the cover film 102 for extruding wrinkles on the cover film 102. Through set up linkage segment 111 on extruded piece 11, can conveniently fix extruded piece 11 on naked support 101, linkage segment 111 can adopt modes such as welding, steel bushing connection or cutting integrated into one piece and naked support 101 fixed connection.

An included angle α between a tangent line of any point on the connection section 111 and a tangent line of any point on the extrusion section 112 may be 5 ° to 180 °. However, if α is too large, the overlapping area of the connecting section 111 and the bare bracket 101 is too small, it is inconvenient to fix the extrusion member 11 to the bare bracket 101, and the subsequent fatigue fracture resistance is poor, and the extrusion member 11 is liable to be detached and broken. Furthermore, the extrusion member 11 is extruded during sheathing, and if α is too large, plastic deformation is likely to occur between the connection section 111 and the extrusion section 112, so that the extrusion member 11 cannot be restored to the initial pre-shaped state after the stent graft 100 is released, and the function of extruding the folds of the stent graft is lost. Therefore, the angle α is preferably 5 ° to 85 °.

The connecting section 111 is preferably an arc-shaped section, and the bending radius R1 of the connecting section 111 is 0.2 mm-2 mm. It can be understood that if the bending radius R1 is too small, the connecting section 111 will form cracks during bending, resulting in poor fatigue resistance of the connecting section 111, and fatigue fracture is likely to occur subsequently, which may cause injury to the patient; if the bend radius R1 is too large, the connecting segment 111 may plastically deform during sheath compression, and may increase the overall compressed volume of the stent graft 100, thereby affecting sheath loading. Therefore, when the bending radius R1 of the connecting section 111 is 0.2mm to 2mm, the extrusion 11 can be made to have good compression and resilience properties.

Referring to fig. 4 again, the covered stent 100 is provided with a limiting member 12, a limiting passage is provided in the limiting member 12, and the extrusion member 11 can movably pass through the limiting passage. When the extrusion piece 11 is compressed and rebounded, the extrusion piece 11 and the limiting piece 12 move relatively, and the limiting piece 12 can prevent the extrusion piece 11 from moving randomly, so that at least part of the extrusion piece 11 is limited in the end area of the film 102. Preferably, the stopper 12 is located entirely within the end region of the film 102, and restricts the extrusion 11 entirely within the end region of the film 102.

The position limiting member 12 can be made of a material with good biological properties, such as nitinol, stainless steel, dacron thread, dacron cloth, PTFE thread, e-PTFE film, and the like. The retaining member 12 may be secured to the inner wall of the stent graft 100 by suturing or the like.

The distance H1 between the stopper 12 and the end of the film 102 in the axial direction is 0.5mm to 2 mm. If the value of H1 is too small, the extrusion member 11 easily slips out of the coating film 102 and cannot effectively extrude wrinkles on the coating film 102; if the value of H1 is too large, the pressing member 11 cannot press the wrinkles at the end portions of the coating film 102, resulting in a poor pressing effect of the wrinkles.

The width H2 of the stopper 12 in the axial direction is 0.11mm to 1.5 mm. If the width H2 is too small, the movement space of the extrusion member 11 in the stopper 12 is small, and the friction force applied to the extrusion member 11 during compression and rebound is large, so that the extrusion member 11 cannot completely rebound; if the width H2 is too large, the overall compressed volume of the stent graft 100 may increase, which may affect the sheathing process.

Referring again to fig. 3, the bare stent 101 includes a connecting portion 101a and an anchoring portion 101b connected to each other, and the covering film 102 is fixed to the connecting portion 101 a. In the present embodiment, both ends of the pressing member 11 are fixed to the connecting portions 101a, respectively, and at least a part of the pressing member 11 is located in the end region of the coating film 102. It is understood that in other embodiments, both ends of the pressing member 11 may also be fixed to the anchoring portions 101b, as long as at least a portion of the pressing member 11 extends into the end region of the coating 102 of the connecting portion 101a and presses the coating 102 outwardly in the end region.

Referring to FIGS. 10 and 11, a second embodiment of the present application provides a stent graft 100 that is substantially identical to the stent graft of the first embodiment, but differs from the first embodiment only in that the extrusion 11 is a complete ring-shaped structure.

In the embodiment shown in FIG. 10, the extrusion 11 is an annular structure that is located on the inner wall of the stent graft 100. The extrusion 11 is fixed to the bare stent 101, and the extrusion 11 is movably connected to the stent graft 102 so that relative movement can occur between the extrusion 11 and the stent graft 102. At least a part of the pressing member 11 is located in an end region of the coating film 102, and presses the coating film 102 in the end region outward. The extrusion 11 is provided with a flexible portion 110, the flexible portion 110 having a small bending strength with respect to the rest of the extrusion 11, and the extrusion 11 is easily bent and deformed at the flexible portion 110 when the stent graft 100 is radially extruded.

Because the extruded piece 11 of this embodiment is complete annular structure, this extruded piece 11 can realize continuous extrusion to tectorial membrane 102, makes tectorial membrane 102 in the tip region more level and more smooth, and the antiseep effect is better. Moreover, when the extruding part 11 is fixed on the bare stent 101 and the covered stent 100 is unfolded, the bare stent 101 provides a force towards the direction of the blood vessel wall to the extruding part 11, which is beneficial for the extruding part 11 to extrude the covering film in the end area of the covering film 102 outwards, so that the covering film in the end area is completely attached to the inner wall of the blood vessel.

It is understood that the embodiment does not limit the specific position of the extrusion member 11 fixed on the stent graft 100, since the extrusion member 11 is a complete ring structure, the extrusion member 11 itself has a certain radial supporting force, in other embodiments, the extrusion member 11 may also be located on the outer wall of the stent graft 100, or the extrusion member 11 is fixed on the stent graft 102 without being fixedly connected with the bare stent 101, at this time, the extrusion member 11 uses its own radial supporting force to drive the stent graft 102 in the end region to move outwards, so as to improve the adherence of the stent graft 102 in the end region, and prevent a gap from being formed between the end of the stent graft 102 and the inner wall of the blood vessel after the stent graft 100 is implanted into the blood vessel.

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 naked support, and connects tectorial membrane on the naked support, its characterized in that, be provided with the extruded article on the covered stent, the extruded article has flexible portion, the bending strength of flexible portion is less than the bending strength of the other positions of extruded article, after the covered stent release, at least some of extruded article are located the tip region of tectorial membrane, and drive tectorial membrane in the tip region moves to the outside.

2. The stent graft of claim 1, wherein the extrusion is located on an inner wall of the stent graft, both ends of the extrusion are fixed to the bare stent, respectively, and the extrusion is movable relative to the stent graft.

3. The stent graft as recited in claim 2, wherein the extrusion comprises a connecting section and an extruded section connected, the connecting section being fixedly connected to the bare stent, at least a portion of the extruded section being located in the end region, the flexible portion being located on the extruded section.

4. The stent graft of claim 2, wherein the bare stent comprises a plurality of turns of undulating rings, the undulating rings comprising a plurality of peaks, a plurality of valleys, and a plurality of connecting rods connecting adjacent peaks and valleys, respectively;

5. The stent graft of claim 2, wherein the extrusion is located in the same annular plane as the bare stent.

6. The stent graft as recited in claim 1, wherein the extrusion is a ring-shaped structure.

7. The stent graft of claim 6, wherein the extrusion is secured to the bare stent.

8. The stent graft as recited in claim 1, wherein the extrusion has a cross-section with a circumscribed circle diameter of 0.1mm to 0.3 mm.

9. The stent graft of claim 1, further comprising a limiting member disposed thereon, wherein a limiting passage is disposed in the limiting member, and the extrusion member is movable through the limiting passage.

10. The stent graft as recited in claim 9, wherein the spacing between the limiting member and the end of the stent graft along the axial direction is 0.5mm to 2mm, and the width of the limiting member along the axial direction is 0.11mm to 1.5 mm.