Covered stent

Abstract

The utility model discloses a covered stent which comprises a stent body and a covering film. The stent body is covered with the covering film, the covering film is provided with a hole opening area, and the hole opening area is provided with a plurality of micropores which are used for enabling fluid to flow to the outside from the interior of the covered stent. Wherein the diameter of the micropores is 1.5-1.8 mm, the density of the micropores is 25-36 per 2 square centimeters, the angle range of the opening area in the circumferential direction of the covered stent is 45-360 degrees, and the length of the opening area in the axial direction of the covered stent is not larger than 12 cm. According to the covered stent, by reasonably arranging the diameters and the density of the micropores, it can be guaranteed that blood flow in branch arteries is laminar flow, branch arterial thrombosis, arteriosclerosis and artery stenosis probability increase and cerebral infarction probability increase caused by the fact that the blood flow is turbulent flow are avoided, and the situation that interlayer cannot be healed due to turbulent flow is avoided; the blood flow pressure of the branch artery is reduced, the blood flow and perfusion amount of the branch artery are guaranteed, and then the patency rate of the branch artery is guaranteed.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, specifically to a covered stent. Background Technology

[0002] Aortic aneurysms (such as short neck abdominal aortic aneurysms and thoracic aortic aneurysms) or aortic dissections are fatal vascular diseases with a relatively high incidence. Before the 1990s, traditional surgical treatments were used, which were difficult, invasive, and prone to complications. In 1994, Dake first reported the use of a self-made endovascular stent graft to treat descending aortic aneurysms, marking the birth of TEVAR. TEVAR (Thoracic Endovascular Aortic Repair) is a minimally invasive treatment for aortic lesions, primarily used to treat aortic aneurysms, dissections, or ruptured blood vessels. TEVAR repairs the lesion by implanting an endovascular stent graft, thereby restoring normal aortic function.

[0003] A covered stent is an implantable device that covers a metal stent with a biocompatible membrane. Its core function is to isolate the diseased blood vessel segment through the membrane, reconstruct blood flow channels, and prevent blood leakage. However, when the lesion involves important branch arteries, traditional covered stents can completely block blood flow to the branch, leading to organ ischemia. Therefore, precisely creating micropores in the covered area corresponding to the branch artery has become a key innovation. These micropores allow blood to perfuse the branch vessel in a controlled manner, maintaining the isolation and sealing of the main vessel while ensuring blood supply to the branch organ.

[0004] However, existing covered stents are prone to the following problems after implantation into diseased vascular segments: branch arteries are prone to thrombosis, which affects blood flow; insufficient blood flow and perfusion in branch arteries; increased cerebral infarction; and aortic dissection cannot heal. Utility Model Content

[0005] Therefore, it is necessary to provide a covered stent to address the problem that existing covered stents cannot heal branch artery stenosis and aortic dissection after implantation into diseased vascular segments.

[0006] A covered scaffold, comprising:

[0007] The support body; and

[0008] A film is applied to the support body. The film has an opening area with multiple micropores. The micropores are used to allow fluid to flow from the inside of the film-coated support to the outside.

[0009] The diameter of the micropores is 1.5-1.8 mm, and the density of the micropores is 25-36 per 2 square centimeters; the angle range of the opening area in the circumferential direction of the film-coated support is 45°-360°; the length of the opening area along the axial direction of the film-coated support is no more than 12 cm.

[0010] In one embodiment, the diameter of the micropores is 1.6-1.7 mm, and the density of the micropores is 25-30 per 2 square centimeters.

[0011] In one embodiment, the diameter of the micropores is 1.6 mm, and the density of the micropores is 25 per 2 square centimeters.

[0012] In one embodiment, the angle range of the opening area in the circumferential direction of the film-coated support is 45°-180°.

[0013] In one embodiment, the covered stent has opposing proximal and distal ends, with the opening region disposed at the proximal end of the covered stent.

[0014] In one embodiment, the distance between the opening area and the proximal end face of the covered stent is 3-8 cm.

[0015] In one embodiment, the length of the opening area along the axial direction of the film-coated support is 3-8 cm.

[0016] In one embodiment, the micropores are arranged in an array in the opening region.

[0017] In one embodiment, the opening area is provided with positioning marks along the edge of the film-coated support in the axial direction.

[0018] In one embodiment, the micropore includes at least one of a circular hole, an elliptical hole, or a polygonal hole.

[0019] The aforementioned covered stent, through the rational arrangement of micropore diameter and density, ensures laminar blood flow within the branch arteries, preventing turbulent flow that could lead to branch artery thrombosis, increased risk of arteriosclerosis and stenosis, and increased risk of stroke. It also prevents aortic dissection from failing to heal. Simultaneously, the rational arrangement of micropore diameter and density reduces blood flow pressure in the branch arteries, ensuring adequate blood flow and perfusion, thereby guaranteeing branch artery patency. This covered stent can be placed at the anterior end of the aorta, including the very anterior portion, whereas other existing perforated stents require fenestration and alignment with the most anterior branch artery before use. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 This is a schematic diagram of the structure of a film-coated stent according to one embodiment;

[0022] Figure 2 This is a schematic diagram illustrating laminar blood flow within a branch artery.

[0023] Figure 3 This is a schematic diagram illustrating turbulent blood flow within a branch artery.

[0024] Figure 4 This is a schematic diagram showing that the interlayer has not healed.

[0025] Figure 5 A schematic diagram showing the blood flow and perfusion volume in the branch arteries before and after the installation of the covered stent;

[0026] Figure 6 This is a schematic diagram showing the relationship between micropore density and branch arterial blood flow pressure.

[0027] Figure 7 This is a schematic diagram of a covered stent with a micropore diameter of 1.5 mm being installed in a blood vessel.

[0028] Figure 8 This is a schematic diagram of a covered stent with a micropore diameter of 1.8 mm being installed in a blood vessel.

[0029] Figure 9 This is a schematic diagram showing that the pressure in the branch arteries is significantly lower than that in the aorta.

[0030] Figure 10 This is a schematic diagram showing that after the implantation of a covered stent, the blood flow in the branch artery is laminar and relatively fast.

[0031] Figure 11 This is a schematic diagram illustrating the effect of orifice shape on flow rate.

[0032] Figure label:

[0033] 10-Stent body, 20-Covering membrane, 201-Proximal end, 202-Distal end, 21-Opening area, 22-Micropore, 23-Marker. Detailed Implementation

[0034] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0037] Please see Figure 1 In one embodiment, the covered stent is generally used to treat aortic aneurysms or aortic dissections, and the stent diameter is generally 26-42 mm. Specifically, the covered stent includes a stent body 10 and a covering 20.

[0038] The stent body 10 is the supporting structure of the entire covered stent and must possess high strength, flexibility, biocompatibility, and fatigue resistance. Generally, the stent body 10 is made of metallic materials, especially alloy materials. For example, the stent body 10 is made of stainless steel.

[0039] The diaphragm 20 is applied to the stent body 10. The diaphragm 20 is used to isolate the diseased blood vessel segment, reconstruct the blood flow channel, and prevent blood leakage. Generally, the diaphragm 20 can be made of PET film material. PET film material has good tear resistance and sewing performance, which can ensure the connection between the diaphragm 20 and the stent body 10.

[0040] The covering 20 has an opening area 21, which has multiple micropores 22. The micropores 22 are used to allow fluid to flow from the inside of the covered stent to the outside, so that the blood in the aorta can flow to the branch arteries. The diameter of the micropores 22 is 1.5-1.8 mm, and the density of the micropores 22 is 25-36 per 2 square centimeters.

[0041] Please see Figures 2 to 4The inventors discovered that the diameter of the micropore 22 affects the blood flow in each branch artery. When the micropore diameter is large, such as 2 mm or greater, the blood flow from the covered stent through the micropore 22 into each branch artery is turbulent. This turbulence increases the risk of branch artery thrombosis, arteriosclerosis, and arterial stenosis, as well as the risk of stroke. Furthermore, turbulence can prevent the healing of aortic dissection. Further, when the diameter of the micropore 22 is 1.9 mm, both turbulent and laminar flow occur simultaneously. However, when the diameter of the micropore 22 is less than 1.9 mm, the blood flow is entirely laminar, with a low risk of arteriosclerosis and branch artery stenosis, high blood flow velocity, maintained cerebral perfusion, and a low risk of stroke.

[0042] like Figure 5 As shown, when the diameter of the micropore 22 is 1.5-1.8 mm, there is no significant difference in perfusion between the branch arteries before and after surgery. However, when the diameter of the micropore 22 is less than 1.5 mm, the blood flow pressure in each branch artery decreases by more than 50%. A decrease in blood flow pressure exceeding 50% can lead to cerebral ischemia, resulting in clinical neurological deficits such as limb weakness, numbness, and slurred speech. In cases exceeding 70%, irreversible cerebral infarction may occur. Furthermore, when the diameter of the micropore 22 is less than 1.5 mm, the endothelium can grow over a long period and cover the micropore 22, leading to occlusion (blockage) and ultimately cerebral infarction. Therefore, the diameter of the micropore 22 should not be less than 1.5 mm.

[0043] Please see Figure 6 The inventors also discovered that the density of the micropores 22 affects the blood flow pressure in the branch arteries. When the diameter of the micropores 22 remained constant, the blood flow pressure in the branch arteries decreased by approximately 12.5%, 16%, 20%, and 23% when the density of the micropores 22 was 4, 9, 16, and 25 per 2 square centimeters, respectively. When the number of micropores 22 per 2 square centimeters exceeded 25, the blood flow pressure in the branch arteries gradually stabilized.

[0044] However, when the number of micropores 22 per 2 square centimeters is greater than 36, the spacing between the micropores 22 becomes very small, the stress concentration at the edge of the pores and the stress superposition in the material area between the pores make the membrane 20 prone to tearing and disintegration under blood flow pressure. The blood flow enters the branch artery in a turbulent manner, causing branch artery thrombosis, increasing the probability of arteriosclerosis and arterial stenosis, increasing the probability of cerebral infarction, and also causing the dissection to fail to heal.

[0045] Therefore, taking into account the blood flow conditions in the branch arteries, the blood flow pressure in the branch arteries, the blood flow rate and perfusion volume in the branch arteries, as well as the stability of the membrane 20, the diameter of the micropores 22 was selected to be 1.5-1.8 mm, and the density of the micropores 22 was 25-36 per 2 square centimeters.

[0046] like Figures 7 to 10 As shown, when the diameter and density of the micropores 22 are within this range, after the covered stent implantation, the blood flow velocity in the three branches above the aorta increases, and all are laminar flow. The pressure in the aorta and branch arteries is evenly distributed, and the pressure in the branch arteries is significantly lower than that in the aorta after passing through the covered stent. Simultaneously, the selected diameter and density of the micropores 22 work synergistically to better match the elastic modulus of the vessel wall and reduce local stress concentration. This allows for better repair of the dissection tear and reduces blood flow obstruction, resulting in a better treatment outcome than other existing techniques.

[0047] Preferably, the diameter of the micropores 22 can be 1.5 mm, 1.6 mm, 1.7 mm, or 1.8 mm. Of course, the diameter of the micropores 22 can also be any value between 1.5 and 1.8 mm. The density of the micropores 22 can be 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, or 36 per 2 square centimeters.

[0048] Preferably, the diameter of the micropores 22 is 1.6-1.7 mm, and the density of the micropores 22 is 25-30 per 2 square centimeters.

[0049] The inventors discovered that when the diameter of the micropores 22 is 1.5 mm, the blood flow pressure in each branch artery decreases by nearly 50%, which can easily lead to cerebral ischemia and clinical neurological deficits such as limb weakness, numbness, and slurred speech. Therefore, to ensure safety as much as possible, the diameter of the micropores 22 should ideally be greater than 1.5 mm. Furthermore, based on the aforementioned pattern of how the density of the micropores 22 affects the blood flow pressure in the branch arteries, it is known that when the number of micropores 22 per 2 square centimeters is greater than 25, the blood flow pressure in the branch arteries gradually tends to stabilize.

[0050] Therefore, under the premise of ensuring that the blood flow conditions in the branch arteries, the blood flow pressure in the branch arteries, and the blood flow and perfusion volume in the branch arteries meet the requirements, using a smaller diameter and a smaller density of micropores 22 can increase the spacing between the micropores 22, thereby avoiding stress concentration at the edge of the pores and stress superposition in the material area between the pores, and thus preventing the membrane 20 from tearing and disintegrating. Specifically, in this embodiment, the diameter of the micropores 22 is 1.6 mm, and the density of the micropores 22 is 25 per 2 square centimeters.

[0051] In one embodiment, the angle range of the perforation region 21 in the circumferential direction of the covered stent is 45°-360°. When the covered stent is inserted into the body through the skin, there is an angle involved. The covered stent automatically rotates during delivery, and this rotation angle is uncontrollable. There is a possibility that the perforation region 21 may not be aligned with the branch artery, leading to branch artery blockage. Therefore, making the angle range of the perforation region 21 360 degrees ensures that the micropores 22 are aligned with the branch artery regardless of how the stent rotates within the body.

[0052] However, if the covered stent has openings throughout its 360° radius, membrane leakage can occur, causing blood to seep into the dissection. Therefore, in this embodiment, the angle range of the opening area 21 in the circumferential direction of the covered stent is 45°-180°. This 45°-180° angle avoids completely opening the covered stent 20, reducing membrane leakage and shortening the healing time by approximately 3 months. The alignment issue between the micropores 22 and the branch arteries can be addressed by adjusting the stent during the procedure, ensuring precise alignment of the micropores 22 with the branch arteries.

[0053] Preferably, the angle occupied by the opening area 21 on the circumference can be 45°, 60°, 90°, 120°, or 180°. To reduce the difficulty of positioning the covered bracket, the angle of the opening area 21 can be made as large as possible, such as the angle occupied by the opening area 21 on the circumference of the covered bracket being 180°.

[0054] Please refer to it again. Figure 1 In one embodiment, the covered stent has a proximal end 201 and a distal end 202. In interventional medicine, the end of the covered stent closer to the heart is typically defined as the proximal end 201, and the end farther from the heart is defined as the distal end 202. An opening region 21 is disposed at the proximal end 201 of the covered stent.

[0055] In one embodiment, the length of the covered stent is 15.0-22.0 cm, the diameter is 28 mm-45 mm, and the taper is 0-12. Preferably, the length of the covered stent can be 15.0 cm, 16.0 cm, 17.0 cm, 18.0 cm, 19.0 cm, 20.0 cm, 21.0 cm, or 22.0 cm. The diameter of the proximal end 201 of the covered stent can be 28 mm, 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, 42 mm, or 45 mm, and the diameter of the distal end 202 of the covered stent can be 28 mm, 30 mm, 32 mm, 34 mm, 36 mm, 38 mm, 40 mm, 42 mm, or 45 mm. The taper of the covered stent can be selected as 0, 2, 4, 6, 8, 10, or 12.

[0056] In one embodiment, the length of the opening region 21 along the axial direction of the covered stent is no more than 12 cm. Here, the axial direction refers to the direction parallel to the axis of the covered stent, and since the covered stent extends along the blood vessel after being installed in the blood vessel, it can also be considered as the extension direction of the blood vessel.

[0057] Through the inventor's research, it was found that the maximum length of each branch artery in normal people and patients with aortic dilatation disease is 86mm and the minimum length is 19mm. In addition, the covered stent requires an anchoring area of ​​25mm. Therefore, the length of the opening area 21 along the axial direction of the covered stent is selected to be no more than 12cm.

[0058] Based on the above embodiments, the length of the opening region 21 along the axial direction of the covered stent is further 3-8 cm to match most patients. Preferably, the length of the opening region 21 along the axial direction of the covered stent can be 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, or 8 cm. Of course, the length of the opening region 21 can also be any value within the range of 3-8 cm.

[0059] In one embodiment, the proximity between the opening region 21 and the proximal end face 201 of the covered stent is 3-8 cm. This distance determines the position of the opening region 21 on the covered stent. Preferably, the distance between the opening region 21 and the proximal end face 201 of the covered stent can be 3cm, 4cm, 5cm, 6cm, 7cm, or 8cm. Of course, the distance between the opening region 21 and the proximal end face 201 of the covered stent can be any value within the range of 3-8cm, and can be adjusted according to the location of each branch artery.

[0060] In one embodiment, the unfolded shape of the opening region 21 is rectangular. That is, one edge of the opening region 21 extends along the circumferential direction of the coating support, and the other adjacent edge of the opening region 21 extends along the axial direction of the coating support, thereby forming a rectangular opening region 21. Of course, in other embodiments, the shape of the opening region 21 can also be other shapes, such as triangular, quadrilateral, pentagonal, and hexagonal shapes, as well as other irregular shapes, which can be selected according to actual needs.

[0061] In one embodiment, the micropores 22 are arranged in an array in the opening region 21. This array arrangement of the micropores 22 in the opening region 21 ensures uniform distribution and consistent spacing between each micropore, thereby guaranteeing stable blood flow in each branch artery, stable blood flow and perfusion volume in the branch arteries, and stable membrane 20. Of course, it is understood that in other embodiments, the micropores 22 may not be arranged in an array in the opening region 21. Alternatively, the micropores 22 may be artificially formed, and the micropores 22 may be arranged approximately uniformly in the opening region 21.

[0062] In one embodiment, the micro-hole 22 includes at least one of circular holes or polygonal holes. That is, the micro-hole 22 can be entirely circular holes, or it can be entirely polygonal holes, or it can be a combination of circular holes and polygonal holes. Among them, the polygonal holes can be triangular holes, rhomboid holes, hexagonal holes, etc. Preferably, in order to facilitate the processing and manufacturing of the micro-hole 22, the micro-holes 22 are all circular holes with a uniform shape.

[0063] To determine the impact of different orifice shapes on flow rate, based on real vascular data, the COMSOL simulation software was used to construct three models, including a circular orifice model, a rhomboid orifice model, and a hexagonal orifice model, using the true lumen of the aortic arch and the LSA (lenticule-like artery) branches. Then, based on the actual blood flow velocity at the inlet and the actual blood pressure at the outlet, COMSOL was used to simulate five pulsation cycles (approximately 5 seconds), and the average flow rate at the LSA outlet within 5 seconds was calculated. This yielded comparative data on the impact of different orifice shapes on flow rate, such as... Figure 11 As shown. From Figure 11 As can be seen, when the porosity of the covered stent is basically the same, the change in the shape of the micropore 22 has no significant effect on the flow rate of the branch artery.

[0064] In one embodiment, the opening area 21 is provided with positioning marks 23 along the axial direction of the covered stent. By designing positioning marks 23 on both sides of the opening area 21, the boundary range of the opening area 21 can be visualized and positioned during the implantation of the covered stent, ensuring the accurate installation position of the opening area 21. Specifically, the positioning marks 23 are visible under X-ray, and the marks 23 can be designed as O-shapes.

[0065] The present application is further illustrated below with reference to embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0066] The dimensions and installation positions of the film-coated supports in Examples 1-33 and Comparative Examples 1-17 are as follows:

[0067] The length of the covered stent is 20cm, the diameter of the covered stent is 30mm, the taper is 4, the length of the opening area 21 along the axial direction of the covered stent is 5cm, the opening area 21 is the proximal end 201 of the covered stent, and the distance between the opening area 21 and the end face of the proximal end 201 of the covered stent is 4cm.

[0068] Then, a computer simulation experiment was conducted on the covered stent. The covered stent of the above-mentioned size and specifications was constructed to simulate the scenario in which the covered stent was installed in the thoracic aorta, with the opening area 21 covering the brachiocephalic trunk, carotid artery, and subclavian artery. The blood flow characteristics, blood flow pressure, patency rate, and dissection healing of the branch arteries of Examples 1-27 and Comparative Examples 1-5 were obtained.

[0069] Table 1: Parameters and test results of Examples 1-33 and Comparative Examples 1-17

[0070] Aperture size (mm) Pore ​​density (number of pores) Drilling position blood flow characteristics branch arteries branch arteries mezzanine Example 1 1.5 25 45° Laminar flow Reduce by 50% (acceptable) Passed (95%) heal Example 2 1.5 25 360° Laminar flow Reduce by 50% (acceptable) Passed (95%) heal Example 3 1.5 25 180° Laminar flow Reduce by 50% (acceptable) Passed (95%) heal Example 4 1.5 30 60° Laminar flow A decrease of 47.7% (qualified) Passed (95%) heal Example 5 1.5 30 120° Laminar flow A decrease of 47.7% (qualified) Passed (95%) heal Example 6 1.5 30 180° Laminar flow A decrease of 47.7% (qualified) Passed (95%) heal Example 7 1.5 35 45° Laminar flow Reduced by 32.5% (Pass) Passed (95%) heal Example 8 1.5 35 60° Laminar flow Reduced by 32.5% (Pass) Passed (95%) heal Example 9 1.5 35 120° Laminar flow Reduced by 32.5% (Pass) Passed (95%) heal Example 10 1.6 25 45° Laminar flow Reduced by 35.1% (Pass) Passed (100%) heal Example 11 1.6 25 360° Laminar flow Reduced by 35.1% (Pass) Passed (100%) heal Example 12 1.6 25 120° Laminar flow Reduced by 35.1% (Pass) Passed (100%) heal Example 13 1.6 30 60° Laminar flow Reduced by 29.7% (Pass) Passed (100%) heal Example 14 1.6 30 120° Laminar flow Reduced by 29.7% (Pass) Passed (100%) heal Example 15 1.6 30 45° Laminar flow Reduced by 29.7% (Pass) Passed (100%) heal Example 16 1.6 35 180° Laminar flow Reduced by 25.5% (Pass) Passed (100%) heal Example 17 1.6 35 360° Laminar flow Reduced by 25.5% (qualified) Passed (100%) heal Example 18 1.6 35 60° Laminar flow Reduced by 25.5% (Pass) Passed (100%) heal Example 19 1.7 25 45° Laminar flow Reduced by 38.8% (Pass) Passed (100%) heal Example 20 1.7 30 45° Laminar flow Reduced by 32.5% (Pass) Passed (100%) heal Example 21 1.7 35 45° Laminar flow Decreased by 27.8% (Pass) Passed (100%) heal Example 22 1.7 25 360° Laminar flow Reduced by 38.8% (Pass) Passed (100%) heal Example 23 1.7 30 360° Laminar flow Reduced by 32.5% (Pass) Passed (100%) heal Example 24 1.7 35 360° Laminar flow Decreased by 27.8% (Pass) Passed (100%) heal Example 25 1.8 25 360° Laminar flow Reduced by 30.9% (Pass) Passed (100%) heal Example 26 1.8 25 45° Laminar flow Reduced by 30.9% (Pass) Passed (100%) heal Example 27 1.8 25 180° Laminar flow Reduced by 30.9% (Pass) Passed (100%) heal Example 28 1.8 30 60° Laminar flow Decreased by 27.9% (Pass) Passed (100%) heal Example 29 1.8 30 45° Laminar flow Decreased by 27.9% (Pass) Passed (100%) heal Example 30 1.8 30 120° Laminar flow Decreased by 27.9% (Pass) Passed (100%) heal Example 31 1.8 35 45° Laminar flow A decrease of 19.8% (qualified) Passed (100%) heal Example 32 1.8 35 360° Laminar flow A decrease of 19.8% (qualified) Passed (100%) heal Example 33 1.8 35 120° Laminar flow A decrease of 19.8% (qualified) Passed (100%) heal Comparative Example 1 1.4 25 360° Laminar flow A reduction of more than 50% (unacceptable) Unqualified (below 90%) heal Comparative Example 2 1.4 16 45° Laminar flow A reduction of more than 50% (unacceptable) Unqualified (below 90%) heal Comparative Example 3 1.9 25 120° Turbulence Unqualified Unqualified Unhealed Comparative Example 4 1.9 30 120° Turbulence Unqualified Unqualified Unhealed Comparative Example 5 1.9 35 120° Turbulence Unqualified Unqualified Unhealed Comparative Example 6 1.9 25 60° Turbulence Unqualified Unqualified Unhealed Comparative Example 7 1.9 30 60° Turbulence Unqualified Unqualified Unhealed Comparative Example 8 1.9 35 60° Turbulence Unqualified Unqualified Unhealed Comparative Example 9 2.0 25 120° Turbulence Unqualified Unqualified Unhealed Comparative Example 10 2.0 30 120° Turbulence Unqualified Unqualified (below 90%) Unhealed Comparative Example 11 2.0 35 120° Turbulence Unqualified Unqualified Unhealed Comparative Example 12 2.0 25 60° Turbulence Unqualified Unqualified Unhealed Comparative Example 13 2.0 30 60° Turbulence Unqualified Unqualified (below 90%) Unhealed Comparative Example 14 2.0 35 45° Turbulence Unqualified Unqualified Unhealed Comparative Example 15 2.0 25 45° Turbulence Unqualified Unqualified Unhealed Comparative Example 16 2.0 30 45° Turbulence Unqualified Unqualified (below 90%) Unhealed Comparative Example 17 2.0 35 45° Turbulence Unqualified Unqualified Unhealed

[0071] Note: In Table 1 above, a branch artery patency rate of 95% or higher is considered acceptable, while a rate below 95% is considered unacceptable. A decrease in branch artery blood flow pressure exceeding 50% is unacceptable, while a decrease of no more than 50% is acceptable.

[0072] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model, and they should all be covered within the scope of the claims and specification of this utility model.

Claims

1. A covered stent, characterized in that, include: Support body; and A film is applied to the support body. The film has an opening area with multiple micropores. The micropores are used to allow fluid to flow from the inside of the film-coated support to the outside. The diameter of the micropores is 1.5-1.8 mm, and the density of the micropores is 25-36 per 2 square centimeters; the angle range of the opening area in the circumferential direction of the film-coated support is 45°-360°; the length of the opening area along the axial direction of the film-coated support is no more than 12 cm.

2. The covered stent according to claim 1, characterized in that, The diameter of the micropores is 1.6-1.7 mm, and the density of the micropores is 25-30 per 2 square centimeters.

3. The covered stent according to claim 2, characterized in that, The diameter of the micropores is 1.6 mm, and the density of the micropores is 25 per 2 square centimeters.

4. The covered stent according to claim 1, 2 or 3, characterized in that, The angle range of the opening area in the circumferential direction of the film-coated support is 45°-180°.

5. The covered stent according to claim 1, characterized in that, The covered stent has a proximal end and a distal end, and the opening area is arranged at the proximal end of the covered stent.

6. The covered stent according to claim 5, characterized in that, The distance between the opening area and the proximal end face of the covered stent is 3-8 cm.

7. The covered stent according to claim 1, 5 or 6, characterized in that, The length of the opening area along the axial direction of the film-coated support is 3-8 cm.

8. The covered stent according to claim 1, characterized in that, The micropores are arranged in an array in the opening region.

9. The covered stent according to claim 1, characterized in that, The opening area is marked with positioning marks along the axial direction of the film-coated support.

10. The covered stent according to claim 1, characterized in that, The micropores include at least one of round holes, elliptical holes, or polygonal holes.

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