Composite functional stent for blood vessels

Abstract

The utility model discloses a composite functional stent for blood vessels, which comprises a mesh-tube-shaped stent main body capable of being released and retracted from a delivery catheter, the proximal end of the stent is in an open cone shape, and the middle part of the stent is in a circular tube shape. The stent far end and the stent near end are respectively provided with a far-end developing mark and a near-end developing mark which are not transmitted by X rays; the diameter of the stent far end is larger than that of the stent body, and the stent far end is in an ellipsoid shape. The stent not only can be used as a thrombus taking stent, but also can be used as an intracranial stent for expanding intracranial stenosis and occlusion, so that the medical cost can be saved, and the risk of a patient can be greatly reduced. The thrombus taking stent is small in contact area with the blood vessel and small in damage, the diameter of the far end of the stent is large, and small broken thrombus is not prone to flowing to the far-end blood vessel; the stent is used as an intracranial stent to expand narrow and blocked cerebral vessels, and the effects of dredging and reconstructing blood flow are achieved; the stent is made of degradable materials and can be absorbed without long-term medicine taking.

Description

Technical Field

[0001] The utility model belongs to the technical field of medical devices, and in particular relates to a composite functional stent for blood vessels. Background Art

[0002] Acute ischemic stroke caused by large vessel occlusion can be treated with mechanical thrombectomy to restore cerebral blood flow, improve neurological function, and significantly benefit patients. Currently, the most commonly used thrombectomy stent is the Solitaire thrombectomy stent or its Solitaire-like counterpart from Medtronic. However, these stents have three major drawbacks: 1) The large contact surface between the stent struts and the vessel wall can damage cerebral vessels during stent extraction (stent withdrawal), potentially leading to vascular dissection and rupture. 2) These stents lack distal protection, allowing fragmented clots to migrate to distal clots during thrombus removal, potentially causing secondary strokes. 3) Clinical data in my country show that up to 35% of patients require intracranial stent placement in severely stenotic vessels after thrombectomy. Many physicians deploy the Solitaire stent in the patient's stenotic vessel after thrombectomy. However, the Solitaire and other thrombectomy stents currently in clinical use are made of non-degradable metal, which is highly thrombogenic. This makes these stents less effective as intracranial stents. Patients need to take antiplatelet drugs or anticoagulants for a long time, and the risk of cerebral hemorrhage is high, and severe cases are life-threatening.

[0003] Stroke (cerebral infarction) is a difficult-to-treat disease that poses the most serious threat to human health and life safety, characterized by significant "three highs" (high morbidity, high disability, and high mortality). Stroke poses a significant threat to human health, inflicting immense suffering on patients and placing a heavy burden on families and society. Intracranial atherosclerotic stenosis (ICAS) is one of the most common causes of stroke worldwide. The development of safe, effective, and cost-effective thrombectomy and intracranial stents for the treatment of stroke has immense clinical and societal significance.

[0004] To address vascular stenosis and occlusion caused by intracranial atherosclerosis, Chinese patent applications 201020659169.5 and 201110416746.7 propose a special-shaped stent. This design involves tying the wires at both ends of a conventional circular tubular braided stent and then inserting them into a display ring. The idea is to deploy the stent into the narrowed or blocked intracranial artery. After 45 to 120 minutes, blood flow gradually resumes due to the stent's expansion. However, a fatal flaw of this stent is that the wires at both ends are completely tied within the display ring, forming a densely woven structure at both ends. This significantly reduces blood flow after entering the proximal end of the stent, promoting thrombosis within the stent, leading to blockage within the stent and, consequently, the vessel itself, posing a significant risk to the patient. Clearly, this type of stent design is unsuitable for long-term intracranial implantation.

[0005] Current specialized intracranial stents in clinical use have the following drawbacks: 1) Metal stents are highly thrombogenic, requiring patients to take long-term antiplatelet or anticoagulant medications, which in many cases can lead to cerebral hemorrhages and even life-threatening conditions. 2) Excessive endothelial proliferation around the stent is inevitable, and given the small size of distal intracranial vessels, the rate of restenosis is high. Restenotic stents are prone to long-term intrastent thrombosis, causing stroke and stent occlusion. 3) Metal stents can produce artifacts that interfere with CT and MRI examinations. Therefore, a composite functional stent for vascular applications has been designed to address these issues.

[0006] It should be noted that the above technical background is merely for the purpose of providing a clear and complete description of the technical solutions of the present invention and to facilitate understanding by those skilled in the art. It should not be assumed that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present invention. Utility Model Content

[0007] In order to overcome the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a composite functional stent for blood vessels.

[0008] In order to achieve the above objectives and other related objectives, the technical solution provided by the present invention is: a composite functional stent for blood vessels, including a stent body in the shape of a mesh tube that can be released from and retracted into a delivery catheter, the proximal end of the stent is an open cone, the middle part of the stent is a circular tube, and the distal end and the proximal end of the stent are respectively provided with a distal end development mark and a proximal end development mark that are not X-ray transparent; the diameter of the distal end of the stent is larger than the diameter of the stent body, and the shape of the distal end of the stent is ellipsoidal.

[0009] In this solution, because the diameter of the stent's distal end is larger than that of the stent's main body, the raised structure at the distal end can better capture the thrombus, facilitating its removal and preventing any dislodged thrombi from traveling to the distal vessel. When the diameter of the stent's distal end is larger than that of the stent's main body, the contact area between the stent's main body and the vessel's inner wall is relatively smaller during thrombus removal, minimizing damage to the vessel caused by the stent's main body during thrombus removal. The ellipsoidal shape of the stent's distal end further minimizes damage to the vessel's inner wall.

[0010] Furthermore, the axial length of the distal end of the stent accounts for 1 / 10 to 1 / 6 of the total axial length of the stent body. In this solution, the contact area between the stent body and the blood vessel wall is reduced while meeting the requirements of thrombus removal at the distal end of the stent.

[0011] Furthermore, the proximal end of the stent is connected to a delivery guidewire covered with an insulating film, and the connection between the distal end of the delivery guidewire and the proximal end of the stent includes a separation section not covered with the insulating film. In this embodiment, the delivery guidewire has a diameter of 0.1 mm to 3 mm and a length of 20 cm to 200 cm.

[0012] Furthermore, the cone angle formed by the proximal end of the stent and the axis of the stent body is 0° to 75°. In this solution, the angle of the proximal end of the stent can play a guiding role when the stent is withdrawn, and also reduces the contact area between the proximal end of the stent and the blood vessel wall.

[0013] Furthermore, the structure of the stent body is woven from a single or multiple filaments or engraved using a laser engraving machine. In this embodiment, when the stent body is woven from a single or multiple filaments, the distal and proximal imaging markers can be woven from a developing material mixed with the stent body. The distal and proximal imaging markers can be made of a high-density metal, including but not limited to platinum, tungsten, gold, and tantalum.

[0014] Furthermore, the diameter of the braided wire of the stent body is 0.01 mm to 0.1 mm; the diameter of the stent body in the released state is 3 mm to 10 mm, and the length is 5 mm to 100 mm.

[0015] Furthermore, the cross-sectional shape of the braided wire is at least one of circular, elliptical, or rectangular. Furthermore, the material of the stent body is at least one of a titanium alloy, a degradable magnesium alloy, a degradable iron alloy, a degradable molybdenum alloy, or a degradable polymer material. In this embodiment, the stent body is preferably made of a degradable material. After implantation into the patient's blood vessels, the stent can be absorbed, the patient does not need to take antiplatelet or anticoagulant drugs for a long time, the risk of cerebral hemorrhage is greatly reduced, and the patient is not interfered with by the stent material when undergoing CT / MRI examinations.

[0016] Furthermore, a polymer film layer is provided on the surface of the stent body, and the material of the polymer film layer is one of polyglycolide, polylactic acid, polyglycolide-lactide or polycaprolactone. In this embodiment, the polymer film layer can protect the stent body.

[0017] Furthermore, a drug layer is provided on the stent body and / or the polymer film. In this solution, the drug layer can be directly administered into the blood vessel, which is convenient for administration.

[0018] Furthermore, the material of the delivery guide wire is at least one of a titanium alloy, a cobalt-chromium alloy or stainless steel. In this solution, the delivery guide wire made of a titanium alloy, a cobalt-chromium alloy or stainless steel material can ensure the hardness and toughness of the delivery guide wire and facilitate operation.

[0019] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0020] 1. The stent of the present invention is used as a thrombus removal stent for treating acute cerebral stroke. Since the contact area between the stent wire and the blood vessel is small, the stent causes little damage to the blood vessel when removing the blood vessel.

[0021] 2. The diameter of the distal end of the stent of the present invention is larger than the diameter of the stent body. Even if small blood clots are broken off, they are unlikely to flow into the distal blood vessels.

[0022] 3. The stent of the present invention can be used as an intracranial stent to expand narrowed and occluded cerebral blood vessels, thereby clearing and reconstructing blood flow.

[0023] 4. The stent is made of degradable materials. After being implanted into the patient's blood vessels, the stent can be absorbed. The patient does not need to take antiplatelet or anticoagulant drugs for a long time. The risk of cerebral hemorrhage is greatly reduced, and the patient will not be disturbed by the stent material when undergoing CT / MRI examinations. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the composite functional stent and delivery guide wire of the utility model;

[0025] Figure 2 This is a schematic diagram of the structure of the delivery guide wire of the present utility model;

[0026] Figure 3 This is a schematic diagram of the composite functional stent of the present invention used as a thrombus removal stent;

[0027] Figure 4 This is a schematic diagram of the composite functional bracket of the utility model as a temporary bracket;

[0028] Figure 5 This is a schematic diagram of the composite functional stent of the utility model used as an intracranial stent;

[0029] In the above figures, 10, stent body; 11, proximal end of the stent; 12, middle part of the stent; 13, distal end of the stent; 14, distal end development mark; 15, proximal end development mark; 20, delivery guide wire; 21, insulating film; 22, separation segment; 30, delivery catheter; 40, thrombus; 50, blood vessel. DETAILED DESCRIPTION

[0030] The following describes the implementation of the present invention through specific embodiments. People familiar with this technology can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0031] It should be noted that in the description of the present utility model, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the utility model product is usually placed when in use. These are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance. Terms such as "horizontal", "vertical", and "overhanging" do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, direct connections, indirect connections via an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0033] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0034] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0035] The utility model provides a composite functional stent for blood vessels, as shown in the attached Figure 1 As shown, the stent comprises a mesh-tube-shaped stent body 10 that can be released and retracted from a delivery catheter 30. The proximal end 11 of the stent body 10 is open and conical, while the middle portion 12 is tubular. The distal end 13 and proximal end 11 are respectively provided with X-ray-opaque distal and proximal markers 14 and 15. The cone angle formed by the proximal end 11 and the axis of the stent body 10 ranges from 0° to 75°. The proximal end 11 is connected to the distal end of a delivery guidewire 20, facilitating the retraction of the stent body 10 into the delivery catheter 30. The delivery guidewire 20 is longer than the delivery catheter 30. To release the stent body 10 after it has been compressed into the delivery catheter 30, press the proximal end of the delivery guidewire 20 and slowly withdraw the delivery catheter 30. The distal end 13, middle portion 12, and proximal end 11 are then released from the delivery catheter 30 in sequence. To retrieve the stent body 10, press the proximal handle of the delivery catheter 30 and slowly withdraw the delivery guidewire 20. The proximal end 11, mid-portion 12, and distal end 13 of the stent are then sequentially retracted into the delivery catheter 30. After the stent body 10 is fully released, its diameter ranges from 3mm to 10mm and its length from 5mm to 100mm. The delivery guidewire 20, which is secured to the stent body 10, ranges from 20cm to 200cm in length and has a diameter of 0.1mm to 3mm.

[0036] As attached Figure 2 As shown, the proximal end 11 of the stent is connected to a delivery guide wire 20 covered with an insulating film 21. The connection between the distal end of the delivery guide wire 20 and the proximal end 11 of the stent includes a separation section 22 without the insulating film 21. The stent body 10 can be disconnected from the delivery guide wire 20 at the separation section 22 after electrolysis, thereby releasing the stent body 10 into the narrowed blood vessel 50.

[0037] The structure of the stent body 10 can be a single wire or a braided stent made by hand or with a braiding machine; it can also be a mesh-like stent directly engraved by a laser engraving machine. The wire material of the stent body 10 woven from multiple wires can be a single material or multiple different materials. The material of the stent body 10 can be at least one of nickel-titanium alloy wire, degradable magnesium alloy wire, degradable molybdenum alloy wire, degradable iron alloy wire, and degradable polymer wire. In addition to the braided wire of the stent body 10, the main stent also has a mixed braided wire made of a high-density metal that develops very well under X-rays. The high-density metal includes platinum, tungsten, gold, or tantalum, which is used to form the distal imaging marker 14 and the proximal imaging marker 15.

[0038] Instructions for use: The stent body 10 is delivered via a delivery catheter 30 to a blood vessel 50 occluded by a thrombus 40. The delivery catheter 30 is pushed past the thrombus 40, ensuring that the mid-section of the stent overlaps the thrombus 40. The delivery guidewire 20 is then pressed and slowly withdrawn to release the stent. The radial expansion force of the stent causes the thrombus 40 to embed within the mesh of the stent body 10. The stent system is then slowly withdrawn to remove the thrombus 40. Because the diameter of the stent distal end 13 is larger than that of the stent body 10, the raised structure of the stent distal end 13 can hold the thrombus 40, preventing it from dislodging and flowing into the distal small blood vessel 50. If there is a clinical need, the delivery catheter 30 carrying the stent body 10 is pushed to the narrowed blood vessel 50 section, ensuring that the middle section of the stent overlaps with the middle section of the narrowed blood vessel 50, and the stent delivery guide wire 20 is pressed and slowly withdrawn to release the stent body 10 in the narrowed blood vessel 50 section. Finally, it is separated from the delivery guide wire 20 by electrolysis and can be retained in the narrowed blood vessel 50 as an intracranial stent.

[0039] Example 1: The diameter of the distal end 13 of the stent is larger than the diameter of the stent body 10, and the shape of the distal end 13 of the stent is ellipsoidal. When the stent body 10 is used as a stent to remove a thrombus 40 for treating acute cerebral stroke, the doctor slowly pushes the delivery catheter 30 with the stent body 10 installed inside through the thrombus 40, then presses the delivery guide wire 20 fixed to the stent body 10 to the proximal end outside the delivery catheter 30, and slowly withdraws the delivery catheter 30, as shown in the attached figure. Figure 3 As shown, the stent body 10 is released and encloses the thrombus 40. Because the stent distal end 13 is ellipsoidal and has a larger diameter than the stent body, the thrombus 40 is contained by the stent distal end 13 and prevented from flowing into the distal blood vessel 50. Using angiography of the blood vessel 50, the stent proximal and distal markers 15, 14 are ensured to cross the thrombus 40. The delivery guidewire 20 is then slowly withdrawn, ultimately transferring the thrombus 40, along with the stent body 10, into the delivery catheter 30, which has a larger inner diameter. Finally, the delivery catheter 30, containing the thrombus 40, is removed from the patient, unblocking the patient's blood flow and alleviating their symptoms.

[0040] In some other embodiments, the wires at the distal end 13 of the stent can be welded together in pairs to form a closed structure.

[0041] Example 2: When the stent body 10 is used as a temporary stent to quickly clear a narrow or blocked blood vessel 50, as shown in the attached Figure 4 As shown, the doctor can deliver the delivery catheter 30 containing the stent body 10 to a more distal position of the stenotic or occluded blood vessel 50. Then, by pressing the delivery guidewire 20 fixed to the stent body 10, the doctor slowly withdraws the delivery catheter 30, releasing the stent. If the doctor is not satisfied with the position of the stent body 10, the doctor can withdraw the stent body 10 into the delivery catheter 30, readjust the position of the delivery catheter 30, and then release the stent body 10 again, ultimately placing the middle portion of the stent body 10 in the stenotic section of the blood vessel 50. Because the stent body 10 acts as an expansion support, the actual inner diameter of the blood vessel 50 at the stenosis increases, blood flow gradually increases, and the patient's symptoms are relieved. After a normal 10 to 30 minutes, the patient's blood flow can be restored. After achieving the treatment goal, the doctor slowly withdraws the delivery guidewire 20 and delivery catheter 30, transfers the stent body 10 to a delivery catheter 30 with a larger inner diameter, and then removes the entire system from the patient.

[0042] Example 3: When the stent body 10 is used as an intracranial stent to expand a narrowed or occluded blood vessel 50, as shown in the attached Figure 5 As shown, the doctor passes the delivery catheter 30, which contains the stent body 10, through the stenosis of the blood vessel 50. Then, the doctor presses the proximal end of the delivery guidewire 20, which is fixed to the stent body 10, and slowly withdraws the delivery catheter 30. The stent body 10 is gradually released from the distal end, dilating the stenotic blood vessel 50, immediately unblocking the patient's blood flow and alleviating symptoms. If the doctor is not satisfied with the position of the stent body 10, the doctor can withdraw the stent body 10 into the delivery catheter 30, readjust the delivery catheter 30 position, and release the stent body 10 again, ensuring that the proximal end imaging mark 15 and the distal end imaging mark 14 of the stent cross the stenosis of the blood vessel 50. After the stent body 10 is released in the desired position, the proximal end of the delivery guidewire 20 is connected to a dedicated electrolytic box. Generally, within 2 minutes, the separation section 22 between the delivery guidewire 20 and the proximal end 11 of the stent will fuse, thereby separating the stent body 10 and the delivery guidewire 20. At this time, the delivery guidewire 20 and delivery catheter 30 can be withdrawn. Since the stent body 10 has an expansion and supporting function, the actual inner diameter of the narrow part of the blood vessel 50 increases, the blood flow gradually increases, and the patient's symptoms are relieved.

[0043] Method of making the bracket: as shown in the attached Figure 1The stent shown can be made into various specifications according to different diameters and lengths required clinically. According to a specific design, a metal cylinder is first processed into a mold with a diameter very close to that of the stent, and a plurality of parallel grooves are processed according to the design. One or more wires are taken and wound along the grooves in a manner of alternating forward and reverse spirals to form a shape with a proximal conical end and a stent body 10 as a mesh tube. The stent and its mold are placed in an oven for heat setting. Taking memory alloy as an example, the heat setting temperature is 450°C to 550°C and the time is 2min to 30min. The setting time is adjusted according to the diameter of the wire and the stent. The smaller the wire diameter and the stent diameter, the shorter the setting time. Take one or more developing rings and fix them to the corresponding positions of the proximal end 11 and the distal end 13 of the stent, or tightly wind the X-ray developed wire into a spring shape and fix it to the corresponding positions of the proximal end 11 and the distal end 13 of the stent to display the positions of the proximal end 11 and the distal end 13 of the stent. Finally, weld the mesh or wire at the proximal end of the stent body 10 and the distal end of the delivery guide wire 20 together to make a finished stent.

[0044] The above implementation methods are only for illustrating the technical concept and features of the utility model. Its purpose is to enable people familiar with this technology to understand the content of the utility model and implement it. It cannot be used to limit the scope of protection of the utility model. Any equivalent changes or modifications made according to the spirit of the utility model should be included in the scope of protection of the utility model.

Claims

1. A composite functional stent for a blood vessel, comprising a stent body (10) in the form of a mesh tube that can be released from and retracted into a delivery catheter (30), wherein the proximal end (11) of the stent is in the form of an open cone, the middle portion (12) of the stent is in the form of a circular tube, and the distal end (13) of the stent and the proximal end (11) of the stent are provided with an X-ray non-transmissive distal end development mark (14) and a proximal end development mark (15), respectively; characterized in that: The diameter of the distal end (13) of the stent is larger than the diameter of the stent body (10), and the shape of the distal end (13) of the stent is ellipsoidal.

2. The composite functional stent for blood vessels according to claim 1, characterized in that: The proximal end (11) of the stent is connected to a delivery guide wire (20) covered with an insulating film (21), and the connection between the distal end of the delivery guide wire (20) and the proximal end (11) of the stent includes a separation section (22) not covered with the insulating film (21).

3. The composite functional stent for blood vessels according to claim 2, characterized in that: The cone angle formed by the proximal end (11) of the stent and the axis of the stent body (10) is 0° to 75°.

4. The composite functional stent for blood vessels according to claim 1, characterized in that: The structure of the stent body (10) is woven from a single wire or multiple wires or engraved by a laser engraving machine.

5. The composite functional stent for blood vessels according to claim 4, characterized in that: The diameter of the braided wire of the stent body (10) is 0.01 mm to 0.1 mm; the diameter of the stent body (10) in the released state is 3 mm to 10 mm, and the length is 5 mm to 100 mm.

6. The composite functional stent for blood vessels according to claim 5, characterized in that: The cross-sectional shape of the braided wire is at least one of circular, elliptical or rectangular.

7. The composite functional stent for blood vessels according to claim 1, characterized in that: The material of the stent body (10) is at least one of a titanium alloy, a degradable magnesium alloy, a degradable iron alloy, a degradable molybdenum alloy or a degradable polymer material.

8. The composite functional stent for blood vessels according to claim 1, characterized in that: The surface of the stent body (10) is provided with a polymer film layer, and the material of the polymer film layer is one of polyglycolide, polylactic acid, polyglycolide lactide or polycaprolactone.

9. The composite functional stent for blood vessels according to claim 1, characterized in that: A drug layer is provided on the stent body (10) and / or the polymer film.

10. The composite functional stent for blood vessels according to claim 2, characterized in that: The material of the delivery guide wire (20) is at least one of titanium alloy, cobalt-chromium alloy or stainless steel.

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