CN114617683A - Medical support - Google Patents

Abstract

The invention provides a medical stent, which comprises a bare stent and a covering film, wherein the covering film is covered on the circumferential surface of the bare stent and is provided with a preset area, creases are arranged on the preset area at intervals along the axial direction of the medical stent, and the creases extend along the circumferential direction of the medical stent; the bare stent comprises a plurality of stent rings arranged at intervals in the axial direction of the medical stent, the stent rings comprise first stent rings, at least part of the first stent rings are arranged corresponding to the predetermined region in the axial direction of the medical stent, and the height of one side of each first stent ring corresponding to the predetermined region is smaller than the height of one side of each first stent ring opposite to the predetermined region in the circumferential direction of the medical stent. The medical stent is suitable for the blood vessel with a bending section, and has the advantages of small straightening force and good fitting with the blood vessel wall.

Description

Medical support

Technical Field

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

Background

At present, the intracavity interventional therapy becomes a common treatment method for a series of aortic diseases such as thoracoabdominal aortic aneurysm and aortic dissection.

There is a substantial spatial distortion of the diseased vessels in both the aneurysm and aortic dissection. When the medical stent is used for intracavity treatment of the diseased blood vessels, such as implantation of the medical stent, the medical stent needs to adapt to the distorted diseased blood vessels, but the existing medical stent often cannot meet the compliance requirement, is difficult to bend in the expected direction after being implanted into the diseased blood vessels, has large straightening force, cannot adapt to the shapes of the diseased blood vessels well, and even stimulates the near ends and the far ends of the blood vessels, so that the possibility of reopening the blood vessels is increased.

Disclosure of Invention

The invention aims to provide a medical stent which can well adapt to the distortion condition of a blood vessel, is attached to the wall of the blood vessel and improves the quality effect.

In order to achieve the purpose, the invention provides a medical stent, which comprises a bare stent and a covering membrane, wherein the covering membrane covers the circumferential surface of the bare stent, the covering membrane is provided with a preset area, creases are arranged on the preset area at intervals along the axial direction of the medical stent, and the creases extend along the circumferential direction of the medical stent; the bare stent comprises a plurality of stent rings arranged at intervals in the axial direction of the medical stent, the stent rings comprise first stent rings, at least part of the first stent rings are arranged corresponding to the predetermined region in the axial direction of the medical stent, and the height of one side of each first stent ring corresponding to the predetermined region is smaller than the height of one side of each first stent ring opposite to the predetermined region in the circumferential direction of the medical stent.

Optionally, the medical stent is for implantation in a target lumen having a curved section, and the predetermined region is for placement on a minor curve side of the curved section.

Optionally, when the medical stent is bent, the predetermined region is folded along at least part of the crease and forms at least one folded part, and the folded part is pressed against the part of the covering membrane adjacent to the folded part.

Optionally, at least one of the first stent rings disposed corresponding to the predetermined region in the axial direction of the medical stent partially overlaps with another one of the stent rings adjacent thereto in the axial direction of the medical stent.

Optionally, the first support ring includes a plurality of first support edges, each first support edge is of a linear structure, the plurality of first support edges are sequentially connected end to end, a V-shaped structure is formed between every two adjacent first support edges, all opening angles of the V-shaped structures are the same, the plurality of first support edges are divided into two rod groups, the first support edges in the same rod group are the same in length and are continuously arranged, the first support edges in different rod groups are different in length, in the circumferential direction, the rod group where the first support edges are located is located on one side corresponding to the predetermined area, and the rod group where the first support edges are located is located on one side opposite to the predetermined area, and the length of the rod group is larger.

Optionally, the stent ring further comprises a second stent ring, the second stent ring is located at the proximal-most end of the bare stent, and the outer diameter of the second stent ring is first increased and then kept constant along the proximal-to-distal direction, or the outer diameter of the second stent ring is first increased and then decreased along the proximal-to-distal direction, and the proximal outer diameter of the second stent ring is smaller than the distal outer diameter thereof.

Optionally, the second stent ring comprises a plurality of arc-shaped stent ribs sequentially connected end to end, and the concave sides of the stent ribs are arranged towards the axis of the bare stent.

Optionally, the joint of two adjacent support edges is formed as a vertex, and two adjacent support edges are in transition through a fillet at the vertex; the apices include proximal apices and distal apices alternately arranged along a circumference of the second stent ring, and a radius of the fillet at the proximal apex is greater than a radius of the fillet at the distal apex.

Optionally, all of the stent rings are connected by the cover.

Optionally, the medical stent is a self-expanding stent.

Compared with the prior art, the medical bracket has the following advantages: the medical stent comprises a bare stent and a covering membrane, wherein the covering membrane covers the circumferential surface of the bare stent, the covering membrane is provided with a preset area, creases are arranged on the preset area at intervals along the axial direction of the medical stent, and the creases extend along the circumferential direction of the medical stent; the bare stent comprises a plurality of stent rings arranged at intervals along the axial direction of the medical stent, the stent rings comprise first stent rings, at least part of the first stent rings are arranged corresponding to the predetermined area in the axial direction of the medical stent, and the height of one side of each first stent ring corresponding to the predetermined area is smaller than that of the side, opposite to the predetermined area, of each first stent ring in the circumferential direction of the medical stent. The medical stent is used for implanting in a bent blood vessel, the preset area is positioned at the small bending side, the covering film can be folded along the crease more easily by using the bending memory at the crease of the preset area so as to improve the compliance of the medical stent, the folding of the covering film resists the straightening force generated by the bare stent, the height of one side of the first stent ring corresponding to the preset area is smaller, the medical stent is easier to bend and better in compliance, and the straightening force can be reduced.

Further, when the medical stent is bent, at least one of the first stent rings disposed corresponding to the predetermined region in the axial direction of the medical stent partially overlaps another stent ring adjacent thereto in the axial direction of the medical stent. The medical stent has the advantages that the medical stent is provided with at least two stent rings which are overlapped with each other in the axial direction of the medical stent, so that the bending compliance of the medical stent can be further improved, the overlapped size of the at least two stent rings can be changed according to the curvature radius of a bent section of a blood vessel after the medical stent is implanted into the blood vessel, and the general applicability of the medical stent is improved.

Drawings

Fig. 1 is a schematic structural diagram of a medical stent provided by the invention according to an embodiment.

FIG. 2 is an enlarged partial schematic view of a medical stent according to an embodiment of the present invention.

FIG. 3 is a partial schematic structural view of a medical stent according to an embodiment of the present invention, which mainly shows a folded portion on a predetermined region of a stent cover.

Fig. 4 is a schematic plan view of a first stent ring of a medical stent provided in accordance with an embodiment of the invention.

Fig. 5 is a schematic structural view of a second stent ring of a medical stent provided in accordance with an embodiment of the present invention.

In the figure: 10-medical stent, 10 a-bend section, 110-stent ring, 111-first stent ring, 111 a-first sub-stent ring, 111 b-second sub-stent ring, 111 c-third sub-stent ring, 111 d-fourth sub-stent ring, 111 e-fifth sub-stent ring, 111 f-sixth sub-stent ring, 111 g-seventh sub-stent ring, 111 h-eighth sub-stent ring, 111 i-ninth sub-stent ring, 1111 a-first sub-stent edge, 1111 b-second sub-stent edge, 112-second stent ring, 1121-second stent edge, 1122 a-proximal vertex, 1122 b-distal vertex, 200-cover, 210-predetermined region, 211-fold, 211 a-first fold, 211 b-second fold, 211 c-third fold, 211d fourth fold, 211e fifth fold, 211f sixth fold, 211g seventh fold, 211h eighth fold.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

Furthermore, each of the embodiments described below has one or more technical features, and thus, the use of the technical features of any one embodiment does not necessarily mean that all of the technical features of any one embodiment are implemented at the same time or that only some or all of the technical features of different embodiments are implemented separately. In other words, those skilled in the art can selectively implement some or all of the features of any embodiment or combinations of some or all of the features of multiple embodiments according to the disclosure of the present invention and according to design specifications or implementation requirements, thereby increasing the flexibility in implementing the invention.

As used in this specification, the singular forms "a", "an" and "the" include plural referents, and the plural forms "a plurality" includes more than two referents unless the content clearly dictates otherwise. As used in this specification, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise, and the terms "mounted," "connected," and "connected" are to be construed broadly and include, for example, either a fixed connection or a releasable connection or an integral connection. Either mechanically or electrically. Either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In this context, the terms "proximal" and "distal" refer to the relative position, orientation of the medical device with respect to the heart during normal use, although "proximal" and "distal" are not intended to be limiting, but "proximal" generally refers to the end of the medical device that is closer to the heart during normal use, and "distal" generally refers to the end that is first farther away from the heart.

To further clarify the objects, advantages and features of the present invention, a more particular description of the invention will be rendered by reference to the appended drawings. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention. The same or similar reference numbers in the drawings identify the same or similar elements.

Fig. 1 shows a schematic structural diagram of a medical stent 10 according to an embodiment of the present invention, and fig. 2 shows an enlarged partial schematic view of the medical stent 10. As shown in fig. 1 and 2, the medical stent 10 includes a bare stent and a covering membrane 200. The covering film 200 is coated on the circumferential surface of the bare stent so that the circumferential surface of the bare stent is closed, so that when the medical stent 10 is implanted into a target lumen such as a blood vessel, a liquid such as blood flowing through the target lumen can only flow in the axial direction in the inner lumen of the medical stent 10. The coating 200 may be coated on the inner circumferential surface and/or the outer circumferential surface of the bare stent, and the coating 200 is connected to the bare stent by any suitable method, such as sewing, bonding, hot melting, and the like, and when the coating is connected by sewing, the material of the suture line may be polyethylene terephthalate, tetrafluoroethylene, or other high-strength polymer material.

In an embodiment of the present invention, with continued reference to fig. 1, the covering membrane 200 has a predetermined area 210, and specifically, the medical stent 10 has a first side and a second side (not labeled) opposite to each other in the circumferential direction, and the predetermined area 210 is located on the first side. The predetermined area 210 is provided with creases (not shown in the drawings) spaced along the axial direction of the medical stent 10, and the creases extend along the circumferential direction of the medical stent 10. The medical stent 10 is used for implanting a target lumen having a curved section such that the medical stent 10 is curved, and the predetermined region 210 is provided on a small curved side of the curved section so that the predetermined region 210 can be folded along at least a part of the fold and form a folded portion 211 as shown in fig. 1 and 3 (the folded portion 211 is not marked in fig. 3, but a first folded portion 211a, a second folded portion 211b, a third folded portion 211c, a fourth folded portion 211d, a fifth folded portion 211e, a sixth folded portion 211f, a seventh folded portion 211g, and an eighth folded portion 211h, which are described later, are marked).

When preparing the medical stent 10, the predetermined region 210 of the graft membrane 200 is first pre-shaped in a state of being at least partially folded in the axial direction of the medical stent 10 such that the axial length of the graft membrane 200 on the first side is smaller than the axial length of the graft membrane 200 on the second side, and at this time, when the graft membrane 200 is coated on the circumferential surface of the bare stent, the portion of the graft membrane 200 on the first side applies a tensile force directed to the first side along the second side to the portion of the graft membrane 200 on the second side, and causes the graft membrane 200 to assume a curved cylindrical structure and restrain the bare stent such that the medical stent 10 is curved, and at the same time, the graft membrane 200 also resists the straightening force generated by the bare stent such that the straightening force of the medical stent 10 is reduced. Then, by applying a pulling force in the axial direction to the cover film 200, the predetermined region 210 is expanded, and the predetermined region 210 retains a trace of folding as the fold due to the bending memory. When the medical stent 10 is bent due to the implantation of a bent segment of a blood vessel and the predetermined region 210 is at a small bent side, the predetermined region 210 is more easily folded along at least a part of the crease, and limits the bare stent, thereby improving the bending performance of the medical stent 10 and reducing the straightening force. Optionally, the material of the covering film 200 includes, but is not limited to, any one of polyethylene terephthalate (PET) and expanded polytetrafluoroethylene (ePTFE).

In an embodiment of the present invention, the target lumen is, for example, an aorta, and the curved section is an aortic arch, and a blood vessel wall on a side of the aortic arch having three branch arteries is a large curved side, and a blood vessel wall on a side opposite to the large curved side is the small curved side. When the target lumen is other blood vessel having a curved section, the minor curvature refers to a blood vessel wall on a side of the curved section near a center of curvature.

With continued reference to fig. 1, the bare stent includes a plurality of stent rings 110 spaced apart along the axial direction of the medical stent 10. The stent ring 110 includes two or more first stent rings 111, and at least a part of the first stent rings 111 is provided in the axial direction of the medical stent 10 so as to correspond to the predetermined region of the stent graft 200. The portion of the medical stent 10 corresponding to the predetermined region 210 in the axial direction is referred to as a bending section 10a, that is, at least a part of the first stent ring 111 is disposed at the bending section 10 a.

With continued reference to fig. 1 in conjunction with fig. 4, in the circumferential direction of the medical stent 10, the height h1 of the side of the first stent ring 111 corresponding to the predetermined region 210 is smaller than the height h2 of the side of the first stent ring 111 opposite to the predetermined region 210. In other words, the height of the first stent rings 111 on the first side is smaller than the height of the first stent rings 111 on the second side, so that the predetermined region 210 has a larger area between two adjacent first stent rings 111, can be folded more easily, and further reduces the straightening force generated when the medical stent 10 is bent.

In a non-limiting implementation manner, the first support ring 111 includes a plurality of first support edges, the first support edges may be a linear structure, the plurality of first support edges are sequentially connected end to end, a V-shaped structure is formed between two adjacent first support edges, and a corner tip of the V-shaped structure is preferably an arc shape. In a case where the opening angles of all the V-shaped structures are the same, the plurality of first support ribs may be divided into two bar groups, the first support ribs in the same bar group have the same length and are arranged in series, and the first support ribs in different bar groups have different lengths. The first support rib with the smaller length may be referred to as a first sub-support rib 1111a, and the first support rib with the larger length may be referred to as a second sub-support rib 1111 b. In preparing the medical stent 10, it is sufficient that the set of rods in which the first stent ridge 1111a is located is disposed on the side corresponding to the predetermined region 210 in the circumferential direction, and the set of rods in which the second stent ridge 1111b is located is disposed on the side opposite to the predetermined region 210. It can be understood that the opening angle of the V-shaped structure, the number and length of the first stent ribs 1111a, and the number and length of the second stent ribs 1111b can be properly set according to the shape and size of the blood vessel to be treated. In addition, the proximal ends of all of the first bracket ribs 1111a may be aligned with the proximal ends of all of the second bracket ribs 1111b, or the distal ends of all of the first bracket ribs 1111a may be aligned with the distal ends of all of the second bracket ribs 1111 b.

Referring back to fig. 1 and 3, when the medical stent 10 is bent, the predetermined region 210 is folded along at least a portion of the crease and forms at least one fold 211 (as labeled in fig. 1), but typically forms a plurality of folds 211 (it is understood that the folds 211 in fig. 1 are partially hidden, and thus a portion of the edge lines of the folds in fig. 1 are shown in phantom lines), and when the medical stent 10 is bent, each fold 211 is pressed against a portion of the cover film 200 adjacent to the fold 211 in the axial direction of the medical stent 10. Specifically, in the embodiment shown in fig. 1 and 3, the predetermined region includes eight folded portions 211, i.e., a first folded portion 211a, a second folded portion 211b, a third folded portion 211c, a fourth folded portion 211d, a fifth folded portion 211e, a sixth folded portion 211f, a seventh folded portion 211g, and an eighth folded portion 211h in the proximal-to-distal direction. The first folded portion 211a is pressed against the second folded portion 211b, the second folded portion 211b is pressed against the third folded portion 211c, the third folded portion 211c is pressed against the third folded portion 211d, the fourth folded portion 211d is pressed against the fifth folded portion 211e, the fifth folded portion 211e is pressed against the sixth folded portion 211f, the sixth folded portion 211f is pressed against the seventh folded portion 211g, the seventh folded portion 211g is pressed against the eighth folded portion 211h, and the eighth folded portion 211h is pressed against a portion of the coating film 200 that is located on a distal end side of the eighth folded portion 211h and adjacent to the eighth folded portion 211 h. This has the advantage of avoiding the fold 211 from extending radially into the lumen of the medical stent 10 (i.e. avoiding the fold 211 from tilting in the lumen of the medical stent 10), which can avoid the fold 211 causing the lumen of the medical stent 10 to decrease, and also reduce the probability of formation of a long-term thrombus.

Further, referring back to fig. 1 and 2, at least one stent ring 110 (actually, a first stent ring 110) disposed in the bending section 10a partially overlaps another stent ring 110 adjacent thereto in the axial direction of the medical stent 10. Here, "at least one of the stent rings 110 disposed at the bending section 10a partially coincides with another stent ring 110 adjacent thereto in the axial direction" may mean that at least one of the stent rings 110 is partially inserted into the lumen of another stent ring 110 adjacent thereto and on the distal side thereof at the predetermined region 210. In detail, in the medical stent 10, as shown in fig. 1 as an example, the number of the first stent rings 111 located in the bending section 10a is eight, and the eight first stent rings 111 are referred to as a first sub-stent ring 111a, a second sub-stent ring 111b, a third sub-stent ring 111c, a fourth sub-stent ring 111d, a fifth sub-stent ring 111e, a sixth sub-stent ring 111f, a seventh sub-stent ring 111g, an eighth sub-stent ring 111h, and a ninth sub-stent ring 111i, respectively, in the proximal direction and the distal direction.

When the medical stent 10 is bent, at the predetermined region 210, at least one of (i) - (r): (ii) the distal end of the first sub-stent ring 111a is inserted into the lumen of the second sub-stent ring 111 b. The distal end of the second sub-stent ring 111b is inserted into the lumen of the third sub-stent ring 111 c. Third, the distal end of the third sub-stent ring 111c is inserted into the lumen of the fourth sub-stent ring 111 d. And fourthly, the distal end part of the fourth sub-stent ring 111d is inserted into the lumen of the fifth sub-stent ring 111 e. The distal end of the fifth sub-stent ring 111e is inserted into the lumen of the sixth sub-stent ring 111 f. Sixthly, the distal end of the sixth sub-stent ring 111f is inserted into the lumen of the seventh sub-stent ring 111 g. Seventh sub-stent ring 111g is inserted into the inner lumen of eighth sub-stent ring 111h at its distal end. The distal end part of the eighth sub-stent ring 111h is inserted into the lumen of the ninth sub-stent ring 111 i.

Fig. 1 shows that the medical stent 10 satisfies the above-described conditions (i) - (iii). The partial overlap of two adjacent stent rings 110 in the axial direction can further enhance the bending compliance of the medical stent 10, and the overlap size between two adjacent stent rings 110 can also be adaptively changed according to the curvature radius of the curved section of the blood vessel when being implanted into the blood vessel, specifically, the smaller the curvature radius of the curved section of the blood vessel, the larger the overlap size of two adjacent stent rings 110, the larger the curvature radius of the curved section of the blood vessel, the smaller the overlap size of two adjacent stent rings 110, such a configuration can make the medical stent 10 better fit the blood vessel wall, and have less straightening force, further reduce the stimulation to the blood vessel wall, and also improve the general applicability of the medical stent 10. In addition, all the stent rings 110 are connected to each other through the covering film 200, so that no other rigid connecting piece is introduced, the mutual binding between all the stent rings 110 is reduced, and the bending compliance of the medical stent 10 is further improved to conform to the vessel shape.

Further preferably, at the bend 10a, the distal end of each of the stent rings 110 is disposed at a corresponding one of the folds 211. Specifically, the distal end of the first stent sub-ring 111a may be disposed at the first fold 211a, the distal end of the second stent sub-ring 111b may be disposed at the second fold 211b, the distal end of the third stent sub-ring 111c may be disposed at the third fold 211c, the distal end of the fourth stent sub-ring 111d may be disposed at the fourth fold 211d, the distal end of the fifth stent sub-ring 111e may be disposed at the fifth fold 211e, the distal end of the sixth stent sub-ring 111f may be disposed at the sixth fold 211f, the distal end of the seventh stent sub-ring 111g may be disposed at the seventh fold 211g, and the distal end of the eighth stent sub-ring 111h may be disposed at the eighth fold 211 h. In this way, the stent ring 110 at the bending section 10a is more easily overlapped with another stent ring 110 adjacent thereto in the axial direction of the medical stent 10, and a radially outward force can also be applied to the corresponding folded part 211 by using the stent ring 110, so that the folded part 211 is effectively pressed against the part of the covering membrane 200 adjacent to the folded part 211, and the folded part 211 is further prevented from tilting into the lumen of the medical stent 10.

Further, with continued reference to fig. 1 in conjunction with fig. 5, the stent ring 110 further includes a second stent ring 112, and the second stent ring 112 may be one in number and disposed at the proximal end of the bare stent, such that all of the first stent rings 111 are located at the distal side of the second stent ring 112. Optionally, the medical stent 10 of the second stent ring 112 has a uniform height in the circumferential direction to facilitate positioning of the second stent ring 112 within the blood vessel. Further preferably, the outer diameter of the second stent ring 112 is increased first and then kept constant along the proximal-to-distal direction, or the outer diameter of the second stent ring 112 is increased first and then decreased along the proximal-to-distal direction, and the proximal outer diameter of the second stent ring 112 is made smaller than the distal outer diameter thereof, so that when the medical stent 10 is implanted into a blood vessel, the middle part or the middle part and the distal part of the second stent ring 112 can be used to contact with the blood vessel wall, so as to avoid the contact between the proximal end part of the second stent ring 112 and the blood vessel wall, reduce the stimulation to the blood vessel wall, and reduce the possibility of triggering a long-term rupture.

In this embodiment, the second bracket ring 112 includes a plurality of second bracket ribs 1121 connected end to end in sequence, the second bracket ribs 1121 are arc-shaped, and the concave sides of the second bracket ribs 1121 are arranged toward the axis of the bare bracket. In this way, the second stent ribs 1121 have a smooth configuration without sharp corners, thereby reducing irritation to the vessel wall. Further, a vertex is formed at a connection position of two adjacent second support ribs 1121, and two adjacent second support ribs 1121 are transited through a round angle at the vertex. Here, the apices of the second stent ring 112 near the proximal end of the medical stent 10 are referred to as proximal apices 1122a, and the apices near the distal end of the medical stent 10 are referred to as distal apices 1122b, and the proximal apices 1122a and the distal apices 1122b are alternately arranged in the circumferential direction of the second stent ring 112. Preferably, the radius of the rounded corner at the proximal apex 1122a is greater than the radius of the rounded corner at the distal apex 1122b, which provides the benefit of minimizing irritation of the vessel wall even if the proximal end of the second stent ring 112 contacts the vessel wall.

In addition, all of the stent rings 110 may be made of a shape memory material such as nitinol, i.e., the medical stent 10 is a self-expanding stent.

Although the present invention is disclosed above, it is not limited thereto. Various modifications and alterations of this invention may be made by those skilled in the art without departing from the spirit and scope of this invention. Thus, if such modifications and variations of the present invention fall within the scope of the present invention and its equivalent technology, it is intended that the present invention also include such modifications and variations.

Claims (10)

1. The medical stent is characterized by comprising a bare stent and a covering membrane, wherein the covering membrane covers the circumferential surface of the bare stent, the covering membrane is provided with a preset area, creases are arranged on the preset area at intervals along the axial direction of the medical stent, and the creases extend along the circumferential direction of the medical stent; the bare stent comprises a plurality of stent rings arranged at intervals in the axial direction of the medical stent, the stent rings comprise first stent rings, at least part of the first stent rings are arranged corresponding to the predetermined region in the axial direction of the medical stent, and the height of one side of each first stent ring corresponding to the predetermined region is smaller than the height of one side of each first stent ring opposite to the predetermined region in the circumferential direction of the medical stent.

2. The medical stent of claim 1, wherein the medical stent is for implantation in a target lumen having a curved section, and the predetermined region is for placement on a minor curve side of the curved section.

3. The medical stent of claim 1 or 2, wherein when the medical stent is bent, the predetermined area is folded along at least a portion of the crease and forms at least one fold, and the fold is pressed against a portion of the covering membrane adjacent to the fold.

4. The medical stent according to claim 1 or 2, wherein at least one of the first stent rings disposed corresponding to the predetermined region in the axial direction of the medical stent partially overlaps with another of the stent rings adjacent thereto in the axial direction of the medical stent.

5. The medical stent according to claim 1, wherein the first stent ring comprises a plurality of first stent ribs, the first stent ribs are of a linear structure, the plurality of first stent ribs are sequentially connected end to end, a V-shaped structure is formed between every two adjacent first stent ribs, the opening angles of all the V-shaped structures are the same, the plurality of first stent ribs are divided into two rod groups, the first stent ribs in the same rod group are the same in length and are continuously arranged, the first stent ribs in different rod groups are different in length, in the circumferential direction, the rod group where the first stent rib with the smaller length is located on one side corresponding to the predetermined region, and the rod group where the first stent rib with the larger length is located on one side opposite to the predetermined region.

6. The medical stent of claim 1, wherein the stent ring further comprises a second stent ring, the second stent ring being located at a proximal-most end of the bare stent, and an outer diameter of the second stent ring increasing first and then remaining constant in a proximal-to-distal direction, or an outer diameter of the second stent ring increasing first and then decreasing in a proximal-to-distal direction, and a proximal outer diameter of the second stent ring being smaller than a distal outer diameter thereof.

7. The medical stent of claim 6, wherein the second stent ring comprises a plurality of sequentially end-to-end curved stent ribs, the concave sides of the stent ribs being arranged towards the axis of the bare stent.

8. The medical stent of claim 7, wherein the junction of two adjacent stent ribs is formed as a vertex, and the two adjacent stent ribs are transitioned at the vertex by a rounded corner; the apices include proximal apices and distal apices alternating in a circumferential direction of the second stent ring, and a radius of the fillet at the proximal apex is greater than a radius of the fillet at the distal apex.

9. The medical stent of claim 1, wherein all of the stent rings are connected by the covering membrane.

10. The medical stent of claim 1, wherein the medical stent is a self-expanding stent.

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