A medical stent

Abstract

The application provides a medical stent, comprising a stent body and a covering film, the stent body comprises a plurality of stent rings arranged along the axial direction of the medical stent, and the covering film is wrapped on the circumferential surface of the stent body; wherein the stent ring comprises a first stent ring and a second stent ring, the first stent ring has a uniform outer diameter in the whole length range of the axial direction, and the outer diameter of the proximal end of the second stent ring is larger than that of the distal end; the stent body is divided into a proximal end part, a middle part and a distal end part arranged along the axial direction of the medical stent, the proximal end part and the distal end part each comprise the first stent ring, and the middle part comprises the second stent ring; the medical stent is configured such that when the medical stent is bent, at least one second stent ring partially overlaps with one stent ring located on the distal side and adjacent to the at least one second stent ring in the axial direction of the medical stent. The medical stent has less stimulation to the blood vessel wall when implanted in a curved blood vessel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical devices, in particular to a medical stent. BACKGROUND

[0002] At present, endovascular intervention therapy has become a common treatment method for a series of aortic diseases such as thoracic and abdominal aortic aneurysm and aortic dissection.

[0003] The diseased blood vessels with aortic aneurysm or aortic dissection basically have a spatially twisted condition. When performing endovascular treatment such as implanting a medical stent on these diseased blood vessels, the medical stent needs to adapt to the twisted diseased blood vessels. The current medical stent mostly comprises a plurality of stent rings arranged in sequence along the axial direction and a covering film wrapped on all the stent rings, wherein each stent ring has a uniform outer diameter over the entire length in the axial direction. Such a medical stent is difficult to bend in the expected direction after being implanted in the diseased blood vessel, resulting in that it cannot well adapt to the morphology of the diseased blood vessel. In view of this, various solutions are provided in the prior art, such as using a variable-height stent ring, at least part of the apex of the stent ring being not connected with the covering film, increasing the distance between two adjacent stent rings, using a braided stent, etc. These medical stents can adapt to the morphology of the diseased blood vessel to a certain extent, but they often generate a large elastic force after being bent, so that the medical stent tends to restore to the unbent morphology, which produces a large stimulation to the blood vessel wall. SUMMARY

[0004] The purpose of the present application is to provide a medical stent which can be bent and adapted to various curved blood vessels and has a smaller stimulation to the blood vessel wall.

[0005] To achieve the above-mentioned purpose, the present application provides a medical stent, characterized in comprising a stent body and a covering film, the stent body comprising a plurality of stent rings arranged in sequence and spaced apart along the axial direction of the medical stent, and the covering film being wrapped on the circumferential surface of the stent body; wherein,

[0006] The stent ring comprises a first stent ring and a second stent ring, the first stent ring has a uniform outer diameter over the entire length in the axial direction, and the proximal end outer diameter of the second stent ring is greater than the distal end outer diameter; the stent body is divided into a proximal end portion, a middle portion and a distal end portion arranged in sequence along the axial direction of the medical stent, the proximal end portion and the distal end portion each comprise the first stent ring, and the middle portion comprises the second stent ring;

[0007] The medical stent is configured such that, when the medical stent is bent, at least one second stent ring and one stent ring located on the distal side thereof and adjacent to each other partially overlap in the axial direction of the medical stent.

[0008] Optionally, the outer diameter of the second stent ring gradually decreases in the direction from the proximal end to the distal end.

[0009] Optionally, the medical stent is used for implanting into a predetermined region in a target lumen, and the predetermined region comprises a curved segment; and the partially overlapped stent rings are located in the curved segment.

[0010] Optionally, all the stent rings are connected by the covering film.

[0011] Optionally, the number of the second stent rings is multiple, and the distance between two adjacent second stent rings in the axial direction of the medical stent is 1mm-20mm.

[0012] Optionally, the second stent ring satisfies: the difference between the maximum outer diameter and the minimum outer diameter is 3mm-5mm.

[0013] Optionally, the minimum outer diameter of the second stent ring is 10mm-40mm.

[0014] Optionally, the change rate of the outer diameter of the second stent ring remains constant in the entire axial length range of the second stent ring.

[0015] Optionally, the second stent ring comprises a first segment and a second segment distributed in the axial direction, and the first segment is connected to the proximal end of the second segment; and the change rate of the outer diameter of the second stent ring in the first segment is smaller than that in the second segment.

[0016] Optionally, the medical stent is a self-expanding stent.

[0017] Compared with the prior art, the medical stent has the following advantages:

[0018] The aforementioned medical stent comprises a stent body and a covering film; the stent body comprises a plurality of stent rings arranged in sequence along the axial direction of the medical stent, and the covering film is wrapped on the circumferential surface of the stent body; wherein the stent ring comprises a first stent ring and a second stent ring, the first stent ring has a uniform outer diameter in the entire length range of the axial direction, and the proximal end outer diameter of the second stent ring is greater than the distal end outer diameter; the stent body is divided into a proximal end portion, a middle portion and a distal end portion arranged in sequence along the axial direction of the medical stent, the proximal end portion and the distal end portion each comprise the first stent ring, and the middle portion comprises the second stent ring; when the medical stent is bent, at least one second stent ring and the stent ring located on the distal side and adjacent to the second stent ring partially overlap in the axial direction of the medical stent, that is, at least one second stent ring is partially inserted into the inner cavity of the stent ring located on the distal side and adjacent to the second stent ring, so that the partial area of the second stent ring is separated from the blood vessel wall, and thus the rebound force generated by the partial area of the second stent ring cannot act on the blood vessel wall, achieving the purpose of reducing the stimulation to the blood vessel wall. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are used to better understand the present application and do not constitute undue limitations on the present application. Among them:

[0020] Figure 1 is a structural schematic diagram of a medical stent provided by the present application according to an embodiment;

[0021] Figure 2 is a partial structural schematic diagram of a second stent ring of a medical stent provided by the present application according to an embodiment;

[0022] Figure 3 is a partial structural schematic diagram of a second stent ring of a medical stent provided by the present application according to another embodiment.

[0023] [The following reference signs are explained as follows]:

[0024] 10-medical stent, 100a-proximal end portion, 100b-middle portion, 100c-distal end portion, 110-stent ring, 111-first stent ring, 112-second stent ring, 1121-first segment, 1122-second segment, 112a-first sub-stent ring, 112b-second sub-stent ring, 112c-third sub-stent ring, 112d-fourth sub-stent ring, 112e-fifth sub-stent ring, 112f-sixth sub-stent ring, 112g-seventh sub-stent ring; 200-covering film;

[0025] 11-first contour line, 12-second contour line. DETAILED DESCRIPTION

[0026] The present application is herein described, by way of example only, with the comprehension that the advantages and utility thereof are apparent, and that modifications, of form, arrangement, proportions, and details of the herein described embodiments can be made by those skilled in the art without departing from the spirit of the application and without diminishing its intended advantages. It is to be understood that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the application, for which reference solely should be had to the appended claims. Moreover, the language used in the specification has been principally selected for readability and instructional purposes and can not have been selected to delineate or circumscribe the application.

[0027] In addition, each of the embodiments described below has one or more technical features, but this does not mean that all technical features in any embodiment must be implemented at the same time, or that only one or all technical features in different embodiments can be implemented separately. In other words, under the premise of implementation, those skilled in the art can selectively implement part or all of the technical features in any embodiment according to the disclosure of the present application, and according to design specifications or implementation needs, or selectively implement a combination of part or all of the technical features in multiple embodiments, thereby increasing the flexibility of the implementation of the present application.

[0028] As used in this specification, the singular forms "a," "an" and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification, the term "or" is generally employed in its sense of "and / or" unless the content clearly dictates otherwise, and the terms "mounting," "connected," and "connection" should be interpreted broadly, for example, can be fixed connection, can be detachable connection, or integral connection. It can be mechanical connection, or electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] In this paper, the terms "proximal" and "distal" are the relative orientation, relative position, direction of elements or actions relative to each other from the perspective of the doctor using the medical device, although "proximal" and "distal" are not restrictive, but "proximal" usually refers to the end of the medical device close to the doctor during normal operation, and "distal" usually refers to the end first entering the patient's body.

[0030] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the objectives of the embodiments of the present invention. The same or similar reference numerals in the drawings represent the same or similar parts.

[0031] Figure 1 A schematic diagram of the structure of a medical stent 10 provided in an embodiment of the present invention is shown. For example... Figure 1 As shown, the medical stent 10 includes a stent body and a covering 200. The stent body includes a plurality of stent rings 110 arranged at intervals along the axial direction of the medical stent 10. The covering 200 covers the circumferential surface of the stent body, thereby sealing the circumferential surface of the stent body. This ensures that when the medical stent 10 is implanted into a blood vessel, blood can only flow axially within the lumen of the medical stent 10. The covering 200 may cover the inner and / or outer circumferential surfaces of the stent body.

[0032] For more details, please refer to [link / reference]. Figure 1 The stent ring 110 includes a first stent ring 111 and a second stent ring 112. The first stent ring 111 has a uniform outer diameter over its entire axial length, and the proximal outer diameter of the second stent ring 112 is larger than its distal outer diameter. The stent body is divided into a proximal portion 100a, a middle portion 100b, and a distal portion 100c arranged sequentially along the axial direction of the medical stent 10. Both the proximal portion 100a and the distal portion 100c include the first stent ring 111, and the middle portion 100b includes the second stent ring 112. In this embodiment, the proximal portion 100a and the distal portion 100c include only the first stent ring 111. The medical stent 10 is configured such that when the medical stent 10 is bent, at least one of the second stent rings 112 partially overlaps with an adjacent stent ring 110 located on its distal side in the axial direction of the medical stent 10.

[0033] It can be understood that the medical stent 10 is a self-expanding stent, that is, the stent rings 110 are made of a high-elasticity material, including but not limited to a shape memory alloy such as a nickel-titanium alloy. The medical stent 10 is used to be implanted in a predetermined region of a target lumen, such as a blood vessel, which includes a curved segment. When the medical stent 10 is implanted in the blood vessel and reaches the predetermined region, the proximal end portion 100a and the distal end portion 100c expand radially and conform to the blood vessel wall in the entire axial length range, so that the medical stent 10 can be positioned in the predetermined region and has good conformability and positioning stability. At the same time, the intermediate portion 100b is at least partially curved, so that the partially overlapping stent rings 110 are located in the curved segment.

[0034] The outer diameter of the proximal end of the second stent ring 112 can be equal to the outer diameter of the first stent ring 111, so that the proximal end of the second stent ring 112 can abut against the blood vessel wall. When the medical stent 10 is curved, at least one of the second stent rings 112 at least partially overlaps with the stent ring 110 located on the distal side and adjacent to it in the axial direction, which means that on the small bending side of the medical stent 10, at least one of the second stent rings 112 is partially inserted into the inner cavity of the stent ring 110 adjacent to it and located on the distal side. Continue to take Figure 1 As shown in the example, Figure 1 The intermediate portion 100b of the medical stent 10 shown includes seven second stent rings 112, which are referred to as a first sub-stent ring 112a, a second sub-stent ring 112b, a third sub-stent ring 112c, a fourth sub-stent ring 112d, a fifth sub-stent ring 112e, a sixth sub-stent ring 112f, and a seventh sub-stent ring 112g in the proximal-to-distal direction. When the medical stent 10 is implanted in the target region and curved, at least one of the following situations ①-⑦ will occur on the small bending side of the medical stent 10:

[0035] ①: The distal end of the first sub-stent ring 112a is inserted into the inner cavity of the second sub-stent ring 112b, so that the first sub-stent ring 112a partially overlaps with the second sub-stent ring 112b. By partially overlapping the first sub-stent ring 112a and the second sub-stent ring 112b, the bending compliance of the medical stent 10 is enhanced, so that the straightening force generated when the medical stent 10 is bent is smaller, and the stimulation to the blood vessel wall is reduced.

[0036] ②: the distal end of the second sub-stent ring 112b is inserted into the inner cavity of the third sub-stent ring 112c, so that the second sub-stent ring 112b and the third sub-stent ring 112c partially coincide, and the partial overlap of the second sub-stent ring 112b and the third sub-stent ring 112b enhances the bending compliance of the medical stent 10, so that the straightening force generated when the medical stent 10 is bent is smaller, reducing the stimulation to the blood vessel wall.

[0037] ③: the distal end of the third sub-stent ring 112c is inserted into the inner cavity of the fourth sub-stent ring 112d, so that the third sub-stent ring 112c and the fourth sub-stent ring 112d partially coincide, and the partial overlap of the third sub-stent ring 112c and the fourth sub-stent ring 112d enhances the bending compliance of the medical stent 10, so that the straightening force generated when the medical stent 10 is bent is smaller, reducing the stimulation to the blood vessel wall.

[0038] ④: the distal end of the fourth sub-stent ring 112d is inserted into the inner cavity of the fifth sub-stent ring 112e, so that the fourth sub-stent ring 112d and the fifth sub-stent ring 112e partially coincide, and the partial overlap of the fourth sub-stent ring 112d and the fifth sub-stent ring 112e enhances the bending compliance of the medical stent 10, so that the straightening force generated when the medical stent 10 is bent is smaller, reducing the stimulation to the blood vessel wall.

[0039] ⑤: the distal end of the fifth sub-stent ring 112e is inserted into the inner cavity of the sixth sub-stent ring 112f, so that the fifth sub-stent ring 112e and the sixth sub-stent ring 112f partially coincide, and the partial overlap of the fifth sub-stent ring 112e and the sixth sub-stent ring 112f enhances the bending compliance of the medical stent 10, so that the straightening force generated when the medical stent 10 is bent is smaller, reducing the stimulation to the blood vessel wall.

[0040] ⑥: the distal end of the sixth sub-stent ring 112f is inserted into the inner cavity of the seventh sub-stent ring 112g, so that the sixth sub-stent ring 112f and the seventh sub-stent ring 112g partially coincide, and the partial overlap of the sixth sub-stent ring 112f and the seventh sub-stent ring 112g enhances the bending compliance of the medical stent 10, so that the straightening force generated when the medical stent 10 is bent is smaller, reducing the stimulation to the blood vessel wall.

[0041] The distal end of the seventh sub-stent ring 112g is inserted into the inner cavity of one of the first stent rings 111 located at the proximal end of the distal portion 100c, so that the seventh sub-stent ring 112g partially overlaps with the first stent ring 111. By partially overlapping the seventh sub-stent ring 112g with one of the first stent rings 111 located at the proximal end of the distal portion 100c, the bending compliance of the medical stent 10 is enhanced, so that the straightening force generated when the medical stent 10 is bent is reduced, and the irritation to the blood vessel wall is reduced.

[0042] As can be understood by those skilled in the art, when the medical stent 10 is bent, the medical stent 10 has opposite first and second profile lines 11 and 12 in a cross section parallel to the axis of the medical stent 10. The first and second profile lines 11 and 12 are both curved, and the bending directions of the first and second profile lines 11 and 12 are the same. The radius of curvature of the first profile line 11 is greater than that of the second profile line 12. The convex side where the first profile line 11 is located is the large bending side of the medical stent 10, and the concave side where the second profile line 12 is located is the small bending side of the medical stent 10.

[0043] In this embodiment, the distance between two adjacent second stent rings 112 in the axial direction of the medical stent 10 can be 1-20 mm, so as to avoid the space for inserting the second stent ring 112 into the adjacent stent ring 110 being insufficient due to too small distance, and also to avoid affecting the fit when bending due to too large distance. The distance between two adjacent second stent rings 112 in the axial direction of the medical stent 10 refers to the distance between the proximal end of one second stent ring 112 and the distal end of the other second stent ring 112. Similarly, the distance between the second stent ring 112 located at the distal end and the first stent ring 111 located at the proximal end of the distal portion 100c in the axial direction of the medical stent 10 can also be 1-20 mm, so that at least one second stent ring 112 can partially overlap with one of the stent rings 110 adjacent to it and located on the distal side thereof in the axial direction of the medical stent 10 when the medical stent 10 is bent.

[0044] It should be understood that the minimum outer diameter of the second stent ring 112, i.e. the outer diameter of the distal end of the second stent ring 112, should not be too small, otherwise the minimum inner diameter of the second stent ring 112 will be too small, which will affect the normal flow of blood. Alternatively, the minimum outer diameter of the second stent ring 112 can be 10mm-40mm, and the maximum outer diameter of the second stent ring 112, i.e. the outer diameter of the proximal end of the second stent ring 112, can be 3mm-5mm larger than the minimum outer diameter of the second stent ring 112, so as to not only ensure flexibility, but also improve the adhesion of the medical stent to the blood vessel and reduce the stimulation to the blood vessel. This is because if the difference between the maximum outer diameter and the minimum outer diameter of the second stent ring 112 is too large, the adhesion of the medical stent to the blood vessel will be poor, and the stimulation to the blood vessel will be large, and if the difference between the maximum outer diameter and the minimum outer diameter of the second stent ring 112 is too small, the overlapping area of the second stent ring 112 will be small, which will reduce the flexibility.

[0045] The present application has no particular limitation on the change mode of the outer diameter of the second stent ring 112, as long as the proximal outer diameter of the second stent ring 112 is larger than the distal outer diameter of the second stent ring 112. For example, in an alternative implementation, the outer diameter of the second stent ring 112 gradually decreases from the proximal end to the distal end. More specifically, as shown in Figure 2 the change rate of the outer diameter of the second stent ring 112 remains constant along the entire length of the axial direction of the second stent ring 112, i.e. the outer diameter of the second stent ring 112 changes according to a first linear equation. Alternatively, as shown in Figure 3 the second stent ring 112 includes a first segment 1121 and a second segment 1122 distributed along the axial direction, and the first segment 1121 is connected to the proximal end of the second segment 1122. The change rate of the outer diameter of the second stent ring 112 on the first segment 1121 is smaller than that on the second segment 1122, in other words, the outer diameter of the first segment 1121 of the second stent ring 112 changes according to a second linear equation, the outer diameter of the second segment 1122 changes according to a third linear equation, and the slope of the second linear equation is smaller than the slope of the third linear equation. The first segment 1121 and the second segment 1122 are designed in this way, so that the medical stent 10 has better adhesion.

[0046] Further, all the stent rings 110 are connected by the covering film 200, so that the medical stent 10 has good flexibility and can bend in any direction to adapt to different shapes of the blood vessel.

[0047] Optionally, the material of the covering film 200 is PET (polyethylene terephthalate) or ePTFE (expanded polytetrafluoroethylene). The covering film 200 is connected to the stent ring 110 by any suitable means such as suturing, bonding, etc. When the covering film 200 is connected to the stent ring 110 by suturing, the material of the suture used to suture the covering film 200 can be PET, PTFE (polytetrafluoroethylene) or other high-strength polymer materials.

[0048] While the application has been disclosed in connection with the preferred embodiments provided herein, it should be understood that many modifications and variations of the described implementations can be made. It is intended that the application disclosed herein be construed as including all such modifications and variations as fall within the scope of the appended claims along with their equivalents.

Claims

1. A medical stent, characterized in that, The medical stent includes a stent body and a covering membrane. The stent body comprises a plurality of stent rings arranged at intervals along the axial direction of the stent. The covering membrane covers the circumferential surface of the stent body. The stent ring includes a first stent ring and a second stent ring. The first stent ring has a uniform outer diameter over its entire axial length, and the proximal outer diameter of the second stent ring is larger than its distal outer diameter. The second stent ring includes a first segment and a second segment distributed along the axial direction, with the first segment connected to the proximal end of the second segment. The rate of change of the outer diameter of the second stent ring in the first segment is less than the rate of change in the second segment. The stent body is divided into a proximal portion, a middle portion, and a distal portion arranged sequentially along the axial direction of the medical stent. Both the proximal portion and the distal portion include the first stent ring, and the middle portion includes the second stent ring. The medical stent is configured such that, when the medical stent is bent, at least one of the second stent rings partially overlaps, in the axial direction, one of the stent rings located on its distal side and adjacent to it.

2. The medical stent according to claim 1, characterized in that, The outer diameter of the second support ring gradually decreases from the proximal end to the distal end.

3. The medical stent according to claim 1, characterized in that, The medical stent is used to be implanted in a predetermined area within a target lumen, the predetermined area including a curved section; the partially overlapping stent ring is located in the curved section.

4. The medical stent according to claim 1, characterized in that, All of the support rings are connected via the membrane.

5. The medical stent according to claim 1, characterized in that, The number of the second stent rings is multiple, and the distance between two adjacent second stent rings in the axial direction of the medical stent is 1mm to 20mm.

6. The medical stent according to claim 1, characterized in that, The second support ring satisfies the following condition: the difference between the maximum outer diameter and the minimum outer diameter is 3mm~5mm.

7. The medical stent according to claim 1 or 4, characterized in that, The minimum outer diameter of the second support ring is 10mm~40mm.

8. The medical stent according to claim 1, characterized in that, The medical stent is a self-expanding stent.

Images