Medical stent

Abstract

The present invention provides a medical stent, the medical stent being elastic, and at least one of a plurality of cross-sections sequentially connected in the axial direction of the medical stent being a non-circular cross-section. The non-circular cross-section of the medical stent of the present invention is formed by a plurality of remote points and two opposite vertices, the remote points being away from the largest circumscribed circle formed by the two vertices and located within the range defined by the largest circumscribed circle. Combining the fact that the medical stent is elastic, when the medical stent is placed in a natural body cavity, due to the squeezing effect of the cavity on the medical stent, the two vertices are subjected to a stronger squeezing effect than the plurality of remote points. Therefore, it will cause the medical stent to deform accordingly to facilitate the transformation of the non-circular cross-section into a circular cross-section, thereby providing a radially supporting force with uniform distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to medical stents. Background Art

[0002] At present, cardiovascular diseases have become the number one killer threatening human life and health. Vascular stent interventional therapy is an effective treatment for vascular occlusion diseases that has developed most rapidly and is widely used clinically, with characteristics such as minimally invasive and highly efficient.

[0003] Vascular stents are used to be implanted into the diseased segment of the lumen to support the stenosed and occluded lumen and keep the lumen unobstructed. Among the performance indicators of vascular stents, the compliance performance and the support performance of the stent play crucial roles in the surgical process and the clinical effect after the operation. The compliance performance of the stent will affect the bending ability of the stent in the delivery catheter. Poor compliance will straighten or even damage the blood vessel, or it will be difficult to reach the lesion site. The supportability of the vascular stent will affect the long-term service ability of the stent. If the supportability of the stent is very poor, it cannot expand the stenosed blood vessel, or even if it can be expanded during the operation, the incidence of restenosis after the operation will be relatively high.

[0004] In the prior art, common vascular stents, such as the vascular stent capable of resisting longitudinal deformation disclosed in the Chinese invention patent with the publication number of CN105167881B, have a circular cross-section in the natural state. Once implanted into the blood vessel, especially at the bifurcation of the blood vessel, due to the long-term extrusion of the blood vessel, it is very easy for the cross-section of the vascular stent to deform, resulting in uneven radial support force of the vascular stent, affecting the treatment effect and increasing the incidence of restenosis of the blood vessel after the operation.

[0005] Therefore, it is necessary to design a new type of medical stent to avoid the above problems existing in the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a medical stent applied to the natural body cavity, so as to be conducive to providing uniform radial support force after it is placed in the cavity to avoid causing the problem of restenosis of the cavity.

[0007] To achieve the above purpose, the medical stent of the present invention has elasticity, and at least one of a plurality of cross-sections sequentially connected along the axial direction of the medical stent is a non-circular cross-section; the non-circular cross-section is formed by a plurality of remote points and two opposite vertices, and the remote points are far away from the largest circumscribed circle formed by the two vertices and are located within the range defined by the largest circumscribed circle.

[0008] The beneficial effects of the medical stent described in the present invention are as follows: at least one of a plurality of cross-sections sequentially connected along the axial direction of the medical stent is a non-circular cross-section; the non-circular cross-section is formed by a plurality of remote points and two opposite vertices, the remote points are far from the largest circumscribed circle formed by the two vertices and are located within the range defined by the largest circumscribed circle. Considering that the medical stent has elasticity, when the medical stent is placed in the natural body cavity, due to the extrusion effect of the cavity on the medical stent, the two vertices are subjected to a stronger extrusion effect than the plurality of remote points. Therefore, it will cause the medical stent to deform accordingly to facilitate the transformation of the non-circular cross-section into a circular cross-section, thereby providing a radially uniform distributed support force.

[0009] Preferably, the non-circular cross-section has a maximum outer diameter and a minimum outer diameter, and the difference between the maximum outer diameter and the minimum outer diameter is greater than 0. The beneficial effects are as follows: Considering that the medical stent has elasticity, when the medical stent is placed in the natural body cavity, due to the extrusion effect of the cavity on the medical stent, the two vertices are subjected to a stronger extrusion effect than the plurality of remote points. Therefore, it will cause the difference between the maximum outer diameter and the minimum outer diameter to tend to decrease, which is beneficial to providing a radially uniform distributed support force.

[0010] Further preferably, each of the plurality of cross-sections is a non-circular cross-section, and the shapes of the plurality of cross-sections are uniform or continuously change along the axial direction. The beneficial effects are as follows: It is beneficial to adapt to different cavity structures.

[0011] Further preferably, the maximum outer diameters of the plurality of cross-sections continuously decrease along the axial direction, and the minimum outer diameters of the plurality of cross-sections continuously change or remain unchanged along the axial direction.

[0012] Further preferably, the part of the medical stent forming the non-circular cross-section is composed of a shape memory material, and the shape memory material has a phase transition temperature. When the environmental temperature where the medical stent is located is not lower than the phase transition temperature, the difference decreases. The beneficial effects are as follows: It is beneficial to provide a radially uniform distributed support force.

[0013] Further preferably, the phase transition temperature is 10 - 30 degrees Celsius.

[0014] Further preferably, the shape memory material is any one of nickel-titanium alloy, titanium-nickel-copper alloy, titanium-nickel-iron alloy, and titanium-nickel-chromium alloy.

[0015] Further preferably, the non-circular cross-section is elliptical.

[0016] Preferably, the front end face of the medical stent includes a plurality of protrusions to form an opening inclined surface, and the opening inclined surface is inclined to the axis of the medical stent. The beneficial effects are as follows: it is beneficial to adapt to the physiological structure at the bifurcation of the natural body cavity, avoiding the problem of affecting the flow of substances on the opposite side, such as blood flow, caused by the protrusion at the proximal end of the stent in the prior art, or the problem of restenosis of the natural body cavity that is likely to occur because the stent is too far from the bifurcation and cannot effectively cover the lesion position and cannot provide reasonable radial support force.

[0017] Further preferably, in the planar expansion structure of the medical stent, the connection lines between the tops of the plurality of protrusions form at least one linear contour line or at least one non-linear contour line.

[0018] Further preferably, the non-linear contour line includes an arc contour line. In the planar expansion structure of the medical stent, the arc contour line bends away from the axis of the medical stent.

[0019] Further preferably, in the planar expansion structure of the medical stent, the angle between the tangent line of the arc contour line formed at the proximal end of the arc contour line and the perpendicular line formed through the proximal end is 0-70 degrees. The perpendicular line is perpendicular to the axis of the medical stent, and the proximal end is the end of the arc contour line close to the axis of the medical stent.

[0020] Further preferably, in the planar expansion structure of the medical stent, the acute angle between the linear contour line and the axis of the medical stent is 20-80 degrees.

[0021] Further preferably, in the planar expansion structure of the medical stent, adjacent linear contour lines have different proximal ends, and the proximal end is the end of the linear contour line close to the axis of the medical stent.

[0022] Further preferably, in the planar expansion structure of the medical stent, there are a plurality of transition protrusions between adjacent linear contour lines or non-linear contour lines. The connection lines between the tops of the plurality of transition protrusions form a straight contour line, and the angle between the straight contour line and the axis of the medical stent is 70-90 degrees.

[0023] Further preferably, the medical stent includes a front section formed by connecting a plurality of closed-loop structures. The front end face is formed by the tops of a plurality of front-end closed-loop structures connected around the axis of the medical stent. The maximum radial length of the front-end closed-loop structure is greater than the maximum radial length of other closed-loop structures except the front-end closed-loop structure.

[0024] Preferably, it further includes a marking part, and the marking part is arranged on the front end face or the end face of the medical stent and is riveted or filled with a radiopaque metal. Brief Description of the Drawings

[0025] Figure 1 It is a schematic cross-sectional view of some blood vessels in a patient's body;

[0026] Figure 2 It is a schematic diagram of a working state after a vascular stent of the prior art is implanted into a blood vessel;

[0027] Figure 3 It is Figure 2 Another schematic diagram of the working state after the vascular stent shown is implanted into a blood vessel;

[0028] Figure 4 It is a schematic structural diagram of a medical stent according to some embodiments of the present invention;

[0029] Figure 5 It is Figure 4 A schematic diagram of a two-dimensional structure formed at the edge of the front end face of the medical stent shown;

[0030] Figure 6 It is Figure 4 A schematic diagram of the working state after the medical stent shown is implanted into a blood vessel;

[0031] Figure 7 It is Figure 1 Another schematic diagram of the working state after the vascular stent shown is implanted into the human body;

[0032] Figure 8 It is Figure 4 Another schematic diagram of the working state after the medical stent shown is implanted into the human body;

[0033] Figure 9 It is a schematic structural diagram of a front section according to an embodiment of the present invention;

[0034] Figure 10 It is Figure 9 A schematic diagram of the planar unfolded structure of the front section shown;

[0035] Figure 11 It is a schematic structural diagram of another front section according to an embodiment of the present invention;

[0036] Figure 12 It is Figure 11 A schematic diagram of the planar unfolded structure formed after the front section shown is cut along the A-A direction;

[0037] Figure 13 It is a schematic structural diagram of yet another front section according to an embodiment of the present invention;

[0038] Figure 14 It is Figure 13 A schematic diagram of the planar unfolded structure formed after the front section shown is cut along the A-A direction;

[0039] Figure 15 Schematic structural diagram of another medical stent according to some embodiments of the present invention;

[0040] Figure 16 Along Figure 15 Schematic cross-sectional structure diagram formed by the B-B section line shown;

[0041] Figure 17 Along Figure 15 Schematic structural diagram of a cross-section formed by the C-C section line shown;

[0042] Figure 18 Along Figure 15 Schematic structural diagram of another cross-section formed by the C-C section line shown. Detailed implementation manners

[0043] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art in the field to which the present invention belongs. The words such as "including" used herein mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items.

[0044] Figure 1 Schematic cross-sectional view of a part of blood vessels in a patient's body. Figure 2 Schematic diagram of a working state after a vascular stent of the prior art is implanted into a blood vessel. Figure 3 For Figure 2 Schematic diagram of another working state after the vascular stent shown is implanted into a blood vessel.

[0045] Referring to Figure 1 , there is a venous blood vessel 12 between the first arterial blood vessel 11 and the second arterial blood vessel 13 in a patient's body. Due to the lesion of the venous blood vessel 12, it is likely to be deformed under the action of the first arterial blood vessel 11 and the second arterial blood vessel 13, thus causing blood vessel stenosis.

[0046] Referring to Figure 2 and Figure 3, the cross-sectional shape of the prior art vascular stent 14 is circular. After being placed into the venous blood vessel 12 with vascular stenosis, the venous blood vessel 12 can be expanded and opened due to the expansion effect. However, the expanded venous blood vessel 12 reacts on the vascular stent 14 due to inertia. Combining the effects of the first arterial blood vessel 11 and the second arterial blood vessel 13 on the venous blood vessel 12, the cross-section of the vascular stent 14 is likely to deform, resulting in uneven radial support force, thus affecting the treatment effect and increasing the incidence of restenosis of the blood vessel after the operation.

[0047] In view of the above problems faced by the prior art, the present invention provides a medical stent applied to the natural body cavity to provide uniform radial support force to avoid causing the problem of restenosis of the cavity, and is particularly suitable for being placed at the cavity bifurcation.

[0048] The natural body cavity includes any one of blood vessels, digestive tract, urinary tract and reproductive tract.

[0049] Figure 4 It is a schematic structural diagram of the medical stent according to some embodiments of the present invention. Figure 5 is Figure 4 a schematic diagram of the two-dimensional structure formed by the edge of the front end face of the shown medical stent.

[0050] In some embodiments of the present invention, at least one of a plurality of cross-sections that are sequentially connected along the axial direction of the medical stent is a non-circular cross-section. The non-circular cross-section has a maximum outer diameter and a minimum outer diameter, and the difference between the maximum outer diameter and the minimum outer diameter is greater than 0.

[0051] Specifically, referring to Figure 4 and Figure 5 , the medical stent 2 has elasticity. A plurality of cross-sections (not marked in the figure) that are sequentially connected along the axial direction of the medical stent 2 form a front section 21.

[0052] Furthermore, referring to Figure 4 , the axial direction is along the central axis of the medical stent 2 and points from the front end face to the end face of the medical stent 2, that is, Figure 4 the D direction shown in the figure. The central axis of the medical stent 2 coincides with the axis 25 of the front section 21.

[0053] The front section 21 is formed by a plurality of front cross-sections (not marked in the figure) that are sequentially connected along the axial direction. Among the plurality of front cross-sections (not marked in the figure), the edge of the front end face of the front section 21 is formed by a plurality of remote points 24 and two opposite vertices, namely the first vertex 22 and the second vertex 23. The plurality of remote points 24, the first vertex 22 and the second vertex 23 form Figure 5The two-dimensional structure 31 shown, and the two-dimensional structure 31 has the non-circular cross-section.

[0054] Specifically, the first vertex 22 and the second vertex 23 form the maximum circumscribed circle 32, and a plurality of the remote points 24 are remote from the maximum circumscribed circle 32 and are located within the range defined by the maximum circumscribed circle 32, so that the front end face of the front section 21 is non-circular and has a maximum outer diameter 33 and a minimum outer diameter 34, and the difference between the maximum outer diameter 33 and the minimum outer diameter 34 is greater than 0.

[0055] Specifically, the two-dimensional structure 31 is non-circular. More specifically, referring to Figure 5 , the two-dimensional structure 31 is an ellipse.

[0056] In some embodiments of the present invention, referring to Figure 4 , the medical stent 2 further includes a marking portion 26, and the marking portion 26 is disposed on the front end face (not marked in the figure) and is riveted or filled with a radiopaque metal.

[0057] Figure 6 For Figure 4 is a schematic diagram of the working state after the medical stent shown is implanted into a blood vessel.

[0058] Referring to Figure 5 and Figure 6 , the medical stent (not marked in the figure) is implanted into the venous blood vessel 12 with vascular stenosis. During the implantation process, the first vertex 22 and the second vertex 23 face the top and bottom of the concave of the venous blood vessel 12 respectively to dilate the venous blood vessel 12 with vascular stenosis. Even if the dilated venous blood vessel 12 reacts on the blood vessel stent 14 due to inertia, or in combination with the combined action of the first artery 11 and the second arterial blood vessel 13, the front section 21 has elasticity and will undergo a recoverable deformation under the reaction of the venous blood vessel 12 or the combined action of the first artery 11 and the second arterial blood vessel 13, so that the difference between the maximum outer diameter 33 and the minimum outer diameter 34 is reduced, which is beneficial to making the front end face (not marked in the figure) more tend to be circular, thereby being beneficial to the uniform distribution of the radial supporting force of the front end face (not marked in the figure).

[0059] In some embodiments of the present invention, referring to Figure 2 , Figure 5 and Figure 6 , under the reaction of the venous blood vessel 12 or the combined action of the first artery 11 and the second arterial blood vessel 13, the front section 21 is finally dilated in the venous blood vessel 12 so that the difference between the large outer diameter 33 and the minimum outer diameter 34 is 0, and the front end face (not marked in the figure) is circular.

[0060] In some embodiments of the present invention, each cross-section of the plurality of cross-sections forming the front section 21 is a non-circular cross-section, the maximum outer diameter of the plurality of cross-sections continuously decreases along the axial direction, and the minimum outer diameter of the plurality of cross-sections continuously changes or remains unchanged along the axial direction, so that the end face of the front section 21 is circular, which is beneficial to adapting to the natural structure of blood vessels and reducing the discomfort of patients.

[0061] In some embodiments of the present invention, the part of the medical stent 2 forming the non-circular cross-section is composed of a shape memory material.

[0062] Specifically, the material of the front section 21 is a shape memory material, and the shape memory material has a phase change temperature. When the ambient temperature where the front section 21 is located is not lower than the phase change temperature, the front section deforms to reduce the difference, which is beneficial to the adaptive adjustment according to the natural structure of blood vessels and reduces the discomfort of patients.

[0063] Specifically, the phase change temperature is 10-30 degrees Celsius.

[0064] More specifically, the shape memory material is any one of nickel-titanium alloy, titanium-nickel-copper alloy, titanium-nickel-iron alloy, and titanium-nickel-chromium alloy.

[0065] Figure 7 For Figure 1 Another schematic diagram of the working state of the blood vessel stent shown after being implanted into the human body.

[0066] Referring to Figure 7 , the first blood vessel 51, the second blood vessel 52, and the third blood vessel 53 in the human body converge to form a blood vessel bifurcation structure. When the diseased part is located at a position close to the first blood vessel 51 in the blood vessel bifurcation structure, it is necessary to implant the blood vessel stent 12 into the first blood vessel 51 and reach the blood vessel bifurcation structure. Since the front end face 121 of the blood vessel stent 12 is perpendicular to the axis of the blood vessel stent (not marked in the figure), in order to place the blood vessel stent 12 in the blood vessel bifurcation structure and make the blood vessel stent 12 generate sufficient supporting force to keep its position relative to the first blood vessel 51 unchanged, the front end face 121 needs to extend out of the intersection of the first blood vessel 51 and the second blood vessel 52. However, this implantation method is very likely to significantly affect the blood flow of the second blood vessel 52 and the third blood vessel 53. If the blood vessel stent 12 is implanted into the first blood vessel 51 and the front end face 121 is away from the blood vessel bifurcation structure, the diseased part cannot be completely covered, and it is also very likely to cause the problem of restenosis due to insufficient proximal supporting force of the blood vessel stent 12.

[0067] Figure 8 For Figure 4 Another schematic diagram of the working state of the medical stent shown after being implanted into the human body.

[0068] To solve the above problems, referring to Figure 4 , a plurality of protrusions (not marked in the figure) on the front end face form an opening inclined surface 27, and the opening inclined surface 27 is inclined to the axis 25 of the front section 21.

[0069] Specifically, the axis 25 is the central axis of the front section 21.

[0070] Referring to Figure 4 and Figure 8 , when the medical stent 2 is implanted into the first blood vessel 51 and reaches the blood vessel bifurcation structure, since the opening inclined surface 27 is inclined to the axis 25, the medical stent 2 is easily placed at the bifurcation of the blood vessel bifurcation structure to adapt to the physiological structure of the blood vessel bifurcation structure, and at the same time, the influence of the structure extending out of the intersection of the first blood vessel 51 and the second blood vessel 52 on blood flow is minimized, and the diseased position can be effectively covered to avoid the problem of blood vessel restenosis caused by insufficient proximal support force.

[0071] In some embodiments of the present invention, referring to Figure 4 , the acute angle α formed between the opening inclined surface 27 and the axis 25 is 20-80 degrees.

[0072] In some embodiments of the present invention, in the planar expansion structure of the front section 21, the connection lines between the tops of the plurality of protrusions form at least one linear contour line or at least one non-linear contour line.

[0073] In some embodiments of the present invention, the number of the linear contour lines is at least 2. In the planar expansion structure of the front section 21, adjacent linear contour lines have different proximal ends, and the proximal end is the end of the linear contour line close to the axis of the front section 21.

[0074] Figure 9 It is a schematic structural diagram of a front section in an embodiment of the present invention. Figure 10 For Figure 9 the schematic diagram of the planar expansion structure of the front section shown.

[0075] The "planar expansion structure" described in the embodiments of the present invention is based on Figure 9For example, it specifically refers to the structure formed by cutting open the side wall of the front section 21 along the cutting direction A-A, and then unfolding it without wrinkles on the same plane according to the actual shape and size of each unit area plane. Specifically, the cutting direction A-A is parallel to the axis 25. The intersection point of the cutting line (not marked in the figure) formed on the side wall of the front section 21 along the cutting direction A-A and the edge of the opening inclined plane (not marked in the figure) surrounded by several protrusions 71 is compared with other cutting lines parallel to the axis 25 and intersecting with the edge of the opening inclined plane (not marked in the figure) surrounded by the several protrusions 71. Along Figure 9 the intersection point of the cutting line (not marked in the figure) formed on the side wall of the front section 21 along the cutting direction A-A shown and the edge of the opening inclined plane (not marked in the figure) surrounded by the several protrusions 71 has the largest perpendicular distance from the axis 25.

[0076] Referring to Figure 9 , the front end face of the front section 21 includes several protrusions 71 and several transition protrusions 72 to form an opening inclined plane (not marked in the figure) surrounded by the several protrusions 71 and a vertical plane (not marked in the figure) surrounded by the several transition protrusions 72. Among them, the opening inclined planes (not marked in the figure) surrounded by the several protrusions 71 are all inclined to the axis 25, and the vertical planes (not marked in the figure) surrounded by the several transition protrusions 72 are perpendicular to the axis 25.

[0077] Specifically, referring to Figure 9 and Figure 10 , in the plane unfolding structure of the front section 21, the adjacent linear contour lines are respectively the first linear contour line 81 and the second linear contour line 82. Both the first linear contour line 81 and the second linear contour line 82 are inclined to the axis 25 and are located on both sides of the axis 25. The first linear contour line 81 and the second linear contour line 82 have different proximal ends, namely the first proximal end 84 and the second proximal end 85. The first linear contour line 81 and the second linear contour line 82 are mirror images of each other with respect to the axis 25.

[0078] In some embodiments of the present invention, the acute angle formed by any one of the first linear contour line 81 and the second linear contour line 82 and the axis 25 is 20 - 80 degrees, so as to better conform to the anatomical shape at the blood vessel bifurcation, achieve the best blood vessel coverage effect, avoid minimizing the impact of the structure extending out of the blood vessel intersection on blood flow, and avoid the problem of blood vessel restenosis caused by insufficient proximal support force.

[0079] If the angle of the acute angle formed is too large, in order to facilitate placement in the body without displacement, the medical stent 2 must be like Figure 7Placed like the vascular stent 12 shown, such that the front end face 121 is more likely to extend out of the intersection of the first blood vessel 51 and the second blood vessel 52, thus affecting the blood flow on the opposite side, and unnecessary harm will be caused to the human body during the process of implanting into the human body; if the angle of the acute angle clamped is too small, the front end of the medical stent 2 is too sharp to generate sufficient radial support force, which is likely to cause the problem of vascular restenosis.

[0080] In some embodiments of the present invention, any one of the first linear contour line 81 and the second linear contour line 82 forms an acute angle with the axis 25 of any one of 30 degrees, 40 degrees, 50 degrees, 60 degrees, and 70 degrees.

[0081] Refer to Figure 9 and Figure 10 , the connection line between the tops of the several transition protrusions 72 forms a straight contour line 83, and the straight contour line 83 is perpendicular to the axis 25.

[0082] In some embodiments of the present invention, the angle formed by the straight contour line 83 and the axis 25 is 70 - 90 degrees. If the included angle is too small, the front section 21 cannot generate sufficient radial support force.

[0083] More specifically, the angle formed by the straight contour line 83 and the axis 25 is any one of 80 degrees and 85 degrees.

[0084] Refer to Figure 9 and Figure 10 , in the planar expansion structure of the front section 21, the maximum radial length L of the closed-loop structure corresponding to the protrusions of the first linear contour line 81 and the second linear contour line 82 is greater than the maximum radial length of other closed-loop structures, and the other closed-loop structures refer to the closed-loop structures corresponding to the protrusions forming the straight contour line 83.

[0085] In some embodiments of the present invention, the non-linear contour line includes an arc contour line. In the planar expansion structure of the front section, the arc contour line bends away from the axis of the front section.

[0086] In some embodiments of the present invention, the number of the arc contour lines is at least 2.

[0087] In some embodiments of the present invention, in the planar expansion structure of the front section 21, the included angle between the tangent line of the arc contour line formed at the near-axis end of the arc contour line and the perpendicular line formed through the near-axis end is 0 - 70 degrees, the perpendicular line is perpendicular to the axis of the front section, and the near-axis end is the end of the arc contour line close to the axis of the front section 21.

[0088] Figure 11Another structural schematic diagram of the front portion of the embodiment of the present invention. Figure 12 is Figure 11 A schematic diagram of the planar unfolded structure formed after cutting the shown front portion along the A-A direction.

[0089] Referring to Figure 11 and Figure 12 , Figure 12 In the shown planar unfolded structure, the connection lines between the tops of the several protrusions 71 form adjacent first arc contour lines 91 and second arc contour lines 92, and both the first arc contour line 91 and the second arc contour line 92 bend away from the axis 25 and converge at the same intersection point 93. The intersection point 93 is the near-axis end of the first arc contour line 91 and the near-axis end of the second arc contour line 92.

[0090] Specifically, the first arc contour line 91 and the second arc contour line 92 are mirror images of each other with respect to the axis 25. Taking the first arc contour line 91 as an example, the tangent formed at the near-axis end of the first arc contour line 91 is the first tangent 94, and the perpendicular line to the axis 25 passing through the intersection point 93 is the first perpendicular line 95.

[0091] In some embodiments of the present invention, referring to Figure 12 , the included angle γ between the first tangent 94 and the first perpendicular line 95 is 0 - 70 degrees.

[0092] Figure 13 Another structural schematic diagram of the front portion of the embodiment of the present invention. Figure 14 is Figure 13 A schematic diagram of the planar unfolded structure formed after cutting the shown front portion along the A-A direction.

[0093] Referring to Figure 13 and Figure 14 , Figure 13 The difference between the shown front portion and Figure 11 the shown front portion is that: Figure 13 The front end face of the shown front portion, in addition to including the inclined opening bevel formed by the several protrusions 71 that is inclined to the axis 25, further includes a plane formed by the several transition protrusions 72 that is perpendicular to the axis 25.

[0094] Referring to Figure 13 and Figure 14, the connecting lines between the tops of the several protrusions 71 form a third arc contour line 1201 and a fourth arc contour line (not marked in the figure). Both the third arc contour line 1201 and the fourth arc contour line (not marked in the figure) bend away from the axis 25 and are located on both sides of the axis 25. The third arc contour line 1201 and the fourth arc contour line (not marked in the figure) are mirror images of each other with respect to the axis 25.

[0095] Specifically, the third arc contour line 1201 and the fourth arc contour line (not marked in the figure) have different proximal ends, namely a third proximal end 1202 and a fourth proximal end 1203 respectively. Taking the fourth arc contour line (not marked in the figure) as an example, the tangent formed by the third proximal end 1202 is a second tangent 1206, and the perpendicular line to the axis 25 formed by the second tangent 1206 is a second perpendicular line 1205.

[0096] In some embodiments of the present invention, referring to Figure 12 , the included angle β between the second tangent 1206 and the second perpendicular line 1205 is 0 - 70 degrees.

[0097] In some embodiments of the present invention, referring to Figure 4 and Figure 5 , the medical stent 2 further includes a rear section 28 connected to the front section 21.

[0098] In some embodiments of the present invention, several rear cross-sections (not marked in the figure) that are sequentially connected along the axial direction, i.e., the D direction, of the rear section 28 have the same structure, and the rear cross-sections (not marked in the figure) have the same structure as the front cross-section of the front section 21.

[0099] Figure 15 is a schematic structural diagram of another medical stent according to some embodiments of the present invention. Figure 16 is Figure 15 a schematic cross-sectional structural diagram formed along the B - B section line shown. Figure 17 is Figure 15 a schematic structural diagram of a cross-section formed along the C - C section line shown.

[0100] Referring to Figures 15 to 17 , the cross-section formed by the front section 11 along the B - B section line is an elliptical cross-section, and the cross-section formed by the rear section 28 along the C - C section line is a circular cross-section, which is applicable to the application scenario where the lesion location is close to the bifurcation of the cavity. By designing at least part of the cross-section of the front section 11 to be elliptical, combined with the fact that both the front section 21 and the rear section 28 are elastic and will undergo recoverable deformation under the extrusion of the cavity, the cross-section formed along the B - B section line will tend to be more Figure 17The circular shape shown, which is conducive to the uniform distribution of the radial supporting force. The rear section 28 mainly provides good conformability to the cavity.

[0101] Figure 18 For along Figure 15 The structural schematic diagram of another cross-section formed along the C-C sectional line shown.

[0102] In some embodiments of the present invention, a plurality of front cross-sections of the front section 21 and a plurality of rear cross-sections of the rear section 28 respectively form two non-circular cross-sections along the same longitudinal sectional line in the same direction, and the two non-circular cross-sections do not coincide along the axial direction.

[0103] Specifically, the angle between the maximum outer diameter of one non-circular cross-section of the front section 21 and the maximum outer diameter of another non-circular cross-section of the rear section 28 is greater than 0 and less than 180 degrees.

[0104] Specifically, referring to Figure 15 、 Figure 16 And Figure 18 , the C-C sectional line and the B-B sectional line are longitudinal sectional lines in the same direction. Figure 18 The medical stent shown and Figure 15 The difference between the medical stents shown is that the cross-section of the rear section 28 formed along the C-C sectional line is an ellipse, denoted as the rear ellipse; the included angle between the maximum outer diameter of the rear ellipse and the maximum outer diameter of the ellipse shown in Figure 16 formed by the front section 21 along the B-B sectional line is 90 degrees.

[0105] Although the embodiments of the present invention have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are all within the scope and spirit of the present invention described in the claims. Moreover, the present invention described herein can have other embodiments and can be implemented or realized in various ways.

Claims

1. A medical stent is applied to a position near the bifurcation of a natural body cavity. The medical stent has elasticity. It is characterized in that: At least one of a plurality of cross-sections that are sequentially connected in the axial direction of the medical stent is a non-circular cross-section; The non-circular cross-section is formed by a plurality of remote points and two opposite vertices. The remote points are away from the largest circumscribed circle formed by the two vertices and are located within the range defined by the largest circumscribed circle; The front end face of the medical stent includes a plurality of protrusions to form an opening inclined surface, and the opening inclined surface is inclined to the axis of the medical stent; The medical stent includes a front section formed by connecting a plurality of closed-loop structures. The front end face is formed by the tops of a plurality of front-end closed-loop structures connected around the axis of the medical stent. The maximum radial length of the front-end closed-loop structure is greater than the maximum radial length of other closed-loop structures except the front-end closed-loop structure; The medical stent includes a rear section connected to the front section; a plurality of front cross-sections of the front section and a plurality of rear cross-sections of the rear section respectively form two non-circular cross-sections along the same longitudinal section line in the same direction, and the two non-circular cross-sections do not coincide in the axial direction; The non-circular cross-section is elliptical; the angle between the major axis of one non-circular cross-section of the front section and the major axis of the other non-circular cross-section of the rear section is greater than 0 and less than 180 degrees; the front section can undergo recoverable deformation under the extrusion of the cavity, so that the cross-section tends to be circular from an ellipse.

2. The medical stent according to claim 1, It is characterized in that, The non-circular cross-section has a maximum outer diameter and a minimum outer diameter, and the difference between the maximum outer diameter and the minimum outer diameter is greater than 0.

3. The medical stent according to claim 2, It is characterized in that, Each of the plurality of cross-sections is a non-circular cross-section, and the shapes of the plurality of cross-sections are uniform or continuously change in the axial direction.

4. The medical stent according to claim 3, It is characterized in that, The maximum outer diameter of the plurality of cross-sections continuously decreases in the axial direction, and the minimum outer diameter of the plurality of cross-sections continuously changes or remains unchanged in the axial direction.

5. The medical stent according to claim 3, It is characterized in that, The part of the medical stent forming the non-circular cross-section is composed of a shape memory material. The shape memory material has a phase change temperature. When the ambient temperature where the medical stent is located is not lower than the phase change temperature, the difference decreases.

6. The medical stent according to claim 5, It is characterized in that, The phase change temperature is 10 - 30 degrees Celsius.

7. The medical stent according to claim 6, It is characterized in that, The shape memory material is any one of nickel-titanium alloy, titanium-nickel-copper alloy, titanium-nickel-iron alloy, and titanium-nickel-chromium alloy.

8. The medical stent according to claim 7, It is characterized in that, In the plane expansion structure of the medical stent, the connection lines between the tops of the plurality of protrusions form at least one linear contour line or at least one non-linear contour line.

9. The medical stent according to claim 8, It is characterized in that, The non-linear contour line includes an arc-shaped contour line. In the planar unfolded structure of the medical stent, the arc-shaped contour line bends away from the axis of the medical stent.

10. The medical stent according to claim 9, wherein, in the planar unfolded structure of the medical stent, the angle between the tangent line of the arc-shaped contour line formed at the proximal end of the arc-shaped contour line and the perpendicular line formed through the proximal end is 0-70 degrees. The perpendicular line is perpendicular to the axis of the medical stent, and the proximal end is the end of the arc-shaped contour line close to the axis of the medical stent.

11. The medical stent according to claim 10, wherein, in the planar unfolded structure of the medical stent, the acute angle formed between the linear contour line and the axis of the medical stent is 20-80 degrees.

12. The medical stent according to claim 11, wherein, in the planar unfolded structure of the medical stent, adjacent linear contour lines have different proximal ends, and the proximal end is the end of the linear contour line close to the axis of the medical stent.

13. The medical stent according to claim 12, wherein, in the planar unfolded structure of the medical stent, there are several transition protrusions between adjacent linear contour lines or non-linear contour lines. The connection lines between the top ends of the several transition protrusions form a straight contour line, and the angle formed between the straight contour line and the axis of the medical stent is 70-90 degrees.

14. The medical stent according to claim 1, wherein, it further includes a marking portion, and the marking portion is arranged on the front end face or the end face of the medical stent, and is riveted or filled with a radiopaque metal.

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