Pulmonary artery stent

Abstract

The present invention relates to the technical field of medical devices, and discloses a pulmonary artery stent. The pulmonary artery stent comprises: a metal stent that can be expanded circumferentially; an isolation membrane that wraps the metal stent to isolate the metal stent from the external environment, and the circumferential tensile strength of the isolation membrane is less than the axial tensile strength. The embodiment of the present invention can not only expand the diameter of the stent according to the change in the diameter of the blood vessel to meet the support performance requirements after the blood vessel is enlarged, but also isolate the metal part of the stent from the blood vessel environment, thereby effectively solving the problem of restenosis in the stent.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a pulmonary artery stent. Background Art

[0002] Pulmonary artery stenosis is common in complex congenital heart disease. With the development of percutaneous interventional treatment technology, the insertion of an implant for the treatment of pulmonary artery stenosis has become an effective treatment for pulmonary artery stenosis. The use of an implant for the treatment of pulmonary artery stenosis for interventional surgery has shown good results in pulmonary artery stenosis, right ventricular outflow tract stenosis, stenosis of the channel after correction of complex congenital heart disease, and stenosis of the systemic-pulmonary shunt duct and collateral vessels. The specific interventional surgery is to introduce a special guide wire, catheter, and an implant for the treatment of pulmonary artery stenosis into the human body under the guidance of medical imaging equipment to perform surgical treatment on pulmonary artery stenosis in the body. Interventional treatment of pulmonary artery stenosis with implants has the characteristics of less trauma, quick recovery, and good results.

[0003] Pulmonary artery stenosis caused by congenital heart disease mainly occurs in people aged 10 to 20 years old, who are in the growth and development stage and whose blood vessels will increase in size with age. However, traditional vascular stents cannot meet the changes in blood vessel size over time; secondly, the local stimulation of the pulmonary artery by traditional vascular stent implantation will further lead to intimal hyperplasia, thus causing restenosis in the stent; thirdly, because the physiological structure of the pulmonary artery is located at the right ventricular outflow port, the blood flow velocity and blood pressure are relatively high when the heart contracts and pumps blood out of the ventricle into the pulmonary artery. After implantation, traditional vascular stents are easily displaced under the impact of blood flow, leading to failure. Summary of the invention

[0004] In view of this, the purpose of an embodiment of the present invention is to provide a pulmonary artery stent, which can not only expand the stent as the diameter of the blood vessel increases so that the stent can continue to provide sufficient support to the blood vessel, but also isolate the metal part of the stent from the blood vessel environment, thereby effectively solving the problem of restenosis within the stent.

[0005] To solve the above technical problems, an embodiment of the present invention provides a pulmonary artery stent, comprising: a circumferentially expandable metal stent; an isolation membrane that wraps the metal stent to isolate the metal stent from the external environment, and the circumferential tensile strength of the isolation membrane is less than the axial tensile strength.

[0006] The embodiment of the present invention adopts a circumferentially expandable metal stent as a supporting structure, so that the metal stent can be expanded when the diameter of the patient's blood vessel changes greatly, so as to continuously ensure the support force of the stent on the blood vessel; at the same time, the metal stent is wrapped with an isolation membrane to isolate it from the blood vessel environment, thereby preventing the metal stent from stimulating the blood vessel and causing intimal hyperplasia, thereby effectively preventing restenosis in the stent.

[0007] In addition, the metal stent includes: a plurality of stent segments; the isolation membrane includes an inner film and a plurality of strip-shaped or cylindrical outer films; the inner film covers the inner surface of the metal stent, and each segment of the outer film is connected to the inner film and covers each stent segment respectively; each stent segment is connected through the isolation membrane.

[0008] In addition, at least one section of the outer film has a skirt, and a drug storage groove is formed between the skirt and the inner film.

[0009] In addition, the isolation membrane is a polytetrafluoroethylene membrane and forms a smooth blood flow channel surface after wrapping the metal stent.

[0010] In addition, the support segment is formed by a plurality of support edges connected end to end and arranged in a wave shape and surrounded along the arrangement direction; the support segment includes a plurality of ordinary edges and extended edges; each support segment has a plurality of ordinary edges provided with telescopic sections, and the plurality of telescopic sections in the same support segment are evenly distributed in the circumferential direction.

[0011] In addition, the supporting edges of adjacent stent segments partially overlap axially.

[0012] In addition, the support segment includes several groups of double wave segments arranged along the circumferential direction, and two wave segments in the double wave segments are symmetrically arranged; wherein, each wave segment in the double wave segment is composed of several supporting edges connected end to end and arranged in a wave shape, and the supporting edges located at the connecting ends of the double wave segments and close to each other serve as connecting edges, and the connecting edges of any two groups of double wave segments adjacent to each other in the circumferential direction are cross-connected.

[0013] In addition, all the wave segments arranged along the circumferential direction in each group of double wave segments in each support segment are connected to form a single-layer double wave support unit, and each of the support segments also includes a reinforced layer double wave support unit; the support edge arrangement structure of the reinforced layer double wave support unit is similar to the support edge arrangement structure of the single-layer double wave support unit, and the connection between the support edges of the reinforced layer double wave support unit forms a vertex, and the vertices on both sides of the axial direction of the reinforced layer double wave support unit are respectively connected integrally with the vertices at the corresponding positions of the single-layer double wave support unit.

[0014] In addition, the connecting edge of each wave segment has a telescopic segment.

[0015] In addition, a double-bend bridge structure is used between the wave segments to achieve the cross connection.

[0016] In addition, the telescopic section is composed of a plurality of metal wires which are connected end to end and arranged in a wave shape.

[0017] In addition, the metal bracket is provided with a plurality of barbs distributed along the circumference. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. It can be understood that the drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0019] Figure 1 A schematic diagram of the three-dimensional structure of a pulmonary artery stent provided in the first embodiment of the present invention;

[0020] Figure 2 A schematic cross-sectional view of a pulmonary artery stent provided in a first embodiment of the present invention;

[0021] Figure 3 An exemplary structural schematic diagram of a metal stent of a pulmonary artery stent provided in the first embodiment of the present invention;

[0022] Figure 4 A schematic diagram of an exemplary structure of a barb of a pulmonary artery stent provided in the first embodiment of the present invention;

[0023] Figure 5 An exemplary structural schematic diagram of a pulmonary artery stent provided in the first embodiment of the present invention;

[0024] Figure 6 A schematic structural diagram of a skirt of a pulmonary artery stent provided in the first embodiment of the present invention;

[0025] Figure 7 A partially cutaway structural schematic diagram of a pulmonary artery stent provided in a first embodiment of the present invention;

[0026] Figure 8 A schematic structural diagram of a metal stent of a pulmonary artery stent provided in a second embodiment of the present invention;

[0027] Fig. 9 A schematic diagram of the structure of a pulmonary artery stent provided in a second embodiment of the present invention;

[0028] Fig.10 A schematic diagram of a partially cutaway structure of a pulmonary artery stent provided in a second embodiment of the present invention;

[0029] Fig.11 for Fig.10 An enlarged schematic diagram of a cutaway portion is shown;

[0030] Fig.12 A schematic diagram of the partial structure of a metal stent of a pulmonary artery stent provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it can be understood by those skilled in the art that in the embodiments of the present invention, many technical details are provided to enable readers to better understand the present invention. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present invention can be implemented.

[0032] The first embodiment of the present invention provides a pulmonary artery stent suitable for intravascular interventional treatment of pulmonary artery stenosis. Figures 1 to 7 As shown, the pulmonary artery stent includes: a metal stent 2 that can expand circumferentially, and an isolation membrane 1 that wraps the metal stent 2 to isolate the metal stent 2 from the external environment, and the circumferential tensile strength of the isolation membrane 1 is less than the axial tensile strength. For example, the isolation membrane 1 can be a polytetrafluoroethylene film, and the circumferential tensile strength of the polytetrafluoroethylene film is less than the axial tensile strength, that is, when the metal stent 2 expands circumferentially, the isolation membrane 1 that wraps it also expands, but the axial size of the isolation membrane 1 is not easy to increase, so that the length of the metal stent can be kept basically unchanged. In this embodiment, the metal stent 2 wrapped by the isolation membrane 1 can be a mesh tube body as a whole, and its diameter can be variable or the same everywhere, and no specific restrictions are made here. The metal stent 2 can be made of stainless steel or cobalt-based alloys, which can be deformed under force but have a certain strength of medical metal pipes, and is processed by laser cutting and electrochemical polishing. Of course, the metal stent can also be prepared by other processing techniques, and no specific restrictions are made here.

[0033] The pulmonary artery stent of this embodiment adopts a circumferentially expandable metal stent as a blood vessel support structure, so that the metal stent can be expanded after the diameter of the patient's blood vessel increases to continuously ensure the stent's support for the blood vessel; and the metal stent is wrapped with an isolation membrane to isolate it from the blood vessel environment, thereby preventing the metal stent from stimulating the blood vessel and causing intimal hyperplasia, thereby effectively preventing restenosis in the stent.

[0034] Figure 3 A schematic diagram of an exemplary unfolded structure of a metal stent 2 is shown in FIG. Figure 3 As shown, the metal stent 2 may include: a plurality of stent segments 20, each stent segment 20 being arranged along the axial direction. Figure 3The metal stent shown includes 6 coaxially arranged support segments 20, but is not limited thereto. In some examples, the metal stent 2 may also be a single support segment. Each stent segment 20 is formed by a plurality of support ribs 20a connected end to end and arranged in a wavy manner, that is, a plurality of support ribs are connected end to end and arranged to form a mesh cylinder, which constitutes a circumferentially expandable support structure, and its circumferential expansion is achieved by the deformation of the support ribs arranged in a wavy manner in each support segment, and the deformation of the support ribs arranged in a wavy manner has no structural restrictions and has a large radial expansion range. The diameter of some metal stents 2 after re-expansion during use can reach twice the diameter after the first expansion. Therefore, the metal stent can be expanded according to the size of the blood vessel after enlargement, so that the stent can provide appropriate support force for the narrow blood vessel.

[0035] In this embodiment, each support segment 20 includes a plurality of common edges and extended edges. Both the common edges and the extended edges are support edges, and the difference lies in the length. Of course, the width and other dimensions of the common edges and the extended edges may also be different. Preferably, each support segment 20 has a plurality of common edges provided with telescopic segments 20b, and the plurality of telescopic segments 20b in the same support segment 20 are evenly distributed in the circumferential direction. Figure 3 As shown, the telescopic section 20b can be composed of a number of metal wires connected end to end and arranged in a wave shape, that is, the axial extension structure of the telescopic section is similar to the circumferential expansion structure of the support section. Each support section 20 can be composed of 2m extended edges and 2n ordinary edges, m and n are positive integers greater than or equal to 1, and the lengths of the extended edges are basically the same, the lengths of the ordinary edges are basically the same, and the long bending structure formed by connecting every two extended edges and the short bending structure formed by connecting every two ordinary edges are arranged alternately. For example, Figure 3 Each support segment 20 shown is composed of 4 elongated edges and 8 ordinary edges, wherein the 4 elongated edges constitute 2 bending structures, and the 8 ordinary edges constitute 4 short bending structures, the 2 long bending structures and the 4 short bending structures are staggered in the circumferential direction, and the 2 telescopic segments are respectively arranged on 2 ordinary edges that are evenly staggered in the circumferential direction, so that the telescopic segments 20b in each support segment 20 are evenly arranged along the circumference. The elongated edges in the support segment 20 help to increase the circumferential expansion range of the metal stent, and the telescopic segments 20b can increase the circumferential expansion range of the metal stent while minimizing the axial retraction of the metal stent. Figure 3As shown, the wave crests of the wavy support structures of each support segment 20 are axially aligned, and the telescopic segments 20b are also axially aligned. The supporting edges 20a of adjacent bracket segments 20 partially overlap axially, so that the metal bracket 2 has better supporting performance. Of course, the supporting edges 20a of the support segments 20 may not overlap axially. In this embodiment, each support segment 20 is a repeating unit with the same structure, but it is not limited to this. In other examples, the structures of each support segment may also be different. In addition, this embodiment does not impose specific restrictions on the number, length, arrangement of the supporting edges in the support segment and the structure of the telescopic segment.

[0036] like Figure 4 As shown, the metal stent 2 may also be provided with a plurality of barbs 20c distributed along the circumference. Specifically, the plurality of barbs 20c may be provided at a plurality of vertex positions in the circumferential direction of the first stent section of the metal stent 2, and the first stent section corresponds to the blood inflow end. When the pulmonary artery stent is placed in the patient's pulmonary artery, the barbs 20c may penetrate into the vessel wall to anchor the pulmonary artery stent in the vessel, thereby reducing the risk of stent displacement when the blood flow velocity is fast or the blood pressure is high.

[0037] like Figure 1 , Figure 5As shown, the isolation film 1 includes an inner film 10 and several strip-shaped or cylindrical outer films 11. The inner film 10 covers the inner surface of the metal stent 2, and each outer film 11 is connected to the inner film 10 and covers each stent segment 20 respectively, and each stent segment 20 is connected through the isolation film 1. Each stent segment of the metal stent 2 is directly maintained as an integral stent structure through the isolation film, so that the connection structure between each stent segment can be eliminated. Specifically, the inner film 10 can be a film layer whose length and diameter are adapted to the length and diameter of the metal stent 2, that is, when each stent segment 20 of the metal stent 2 is sleeved on the outer surface of the inner film 10, the inner film 10 can cover the entire inner surface of the metal stent 2. In practical applications, the inner film can be put on the tubular mold, and then the stent segments of the metal stent are put on the outer surface of the inner film in sequence, and then each section of the cylindrical outer film 11 is put on the corresponding stent segment, or each section of the strip outer film 11 is wrapped around the corresponding stent segment, and each section of the outer film is hot-melted or bonded to the inner film, so that each stent segment is covered in the film layer. In this embodiment, the isolation membrane 1 forms a smooth blood flow channel surface after wrapping the metal stent 2, that is, the inner surface of the isolation membrane is smooth and wrinkle-free, thereby effectively preventing the formation of thrombus. It should be noted that the connection of the support ribs 20a of the stent segment 20 forms the apex of the stent segment 20. In order to ensure the circumferential expansion performance of each stent segment 20, the apex of the stent segment 20 and the support ribs 20a should have a certain active area in the isolation membrane 1. Therefore, the connection area (hot-melt or bonding area) between the outer film 11 and the inner film 10 should be set outside the apex of the stent segment 20 and the active area of ​​the support ribs.

[0038] Optionally, in this embodiment, at least one section of the outer film 11 has a skirt 110, and a drug storage tank is formed between the skirt 110 and the inner film 10. The skirt is a film section of a certain length retained on the outer film that is not connected to the inner film 10, so that a drug storage tank structure similar to a pocket is formed between the skirt 110 and the inner film 10. Figure 1 , Figure 5 as well as Figure 6 As shown, each outer film 11 has a skirt, so that each outer film 11 forms a drug storage tank. The drug storage tank can be used to store anti-vascular stenosis drugs for targeted drug delivery during treatment, and the barrier effect of the film can achieve a certain drug sustained release effect.

[0039] The pulmonary artery stent of this embodiment can be expanded a second time during use according to the patient's vascular growth, thereby continuously providing sufficient support for the pulmonary artery. The isolation membrane isolates the metal stent from the vascular environment, which can effectively prevent restenosis within the stent. The barbs can more reliably anchor the stent to the vascular wall to prevent the stent from shifting during use.

[0040] The second embodiment of the present invention provides a pulmonary artery stent. The main difference between this embodiment and the first embodiment is that the structure of the stent segment of the metal stent is different.

[0041] like Figure 8 As shown, the stent segment 20 of the metal stent 2 of the pulmonary artery stent includes: a plurality of groups of double wave segments 200 arranged in the circumferential direction, and two wave segments in the double wave segments 200 are symmetrically arranged. Among them, each wave segment in the double wave segment 200 is composed of a plurality of supporting ridges 20a connected end to end and arranged in a wave shape, and the supporting ridges 20a located at the connecting ends of the double wave segments 200 and close to each other serve as connecting ridges, and the connecting ridges of any two groups of double wave segments adjacent in the circumferential direction are cross-connected, so that the wave segments on the same side of the axial direction in the adjacent groups of double wave segments are connected to form an integrated single support unit in the circumferential direction, and the two single support units are connected to form an integrated unit in the axial direction. The lengths of the supporting ridges 20a in the two single support units in the support segment 20 in this embodiment are roughly the same, which is beneficial for the stent to maintain a more balanced support force on the blood vessel wall in the circumferential direction after expansion compared with the structure with lengthened ridges and ordinary ridges. Optionally, in this embodiment, a double-bend (i.e., "S"-shaped) bridge structure 20d is used between the wave segments to achieve cross-connection, which is helpful to avoid axial retraction of the stent. Optionally, the connecting edge 20a of each wave segment may have a telescopic segment 20b. The telescopic segment 20b may be composed of a plurality of metal wires connected end to end and arranged in a wave shape. The telescopic segment and the double-bend bridge structure make the stent have better expansion performance. Figure 8 As shown, each support segment 20 can be a repeating unit with the same structure, and the crests of the wavy-arranged support structures of adjacent support units in adjacent support segments 20 are axially aligned. However, it is not limited to this. In other examples, the crests and troughs of adjacent wavy-arranged support structures can also be axially aligned.

[0042] like Figures 9 to 11 As shown, the multiple support segments are wrapped by an isolation membrane composed of an inner film and multiple outer films 11. The relevant structure of the isolation membrane is similar to that of the first embodiment and will not be repeated here.

[0043] The pulmonary artery stent of this embodiment not only has excellent expansion performance and is not easy to retract axially, but also has a more balanced supporting force.

[0044] The third embodiment of the present invention provides a pulmonary artery stent. Based on the second embodiment, this embodiment further improves the structure of the support segment of the metal stent.

[0045] like Fig.12As shown, the metal stent of the pulmonary artery stent of this embodiment includes a two-layer support structure, and this embodiment does not specifically limit the number of layers of the support structure. The metal stent of the pulmonary artery stent includes a plurality of support segments 20, each of which includes a plurality of groups of double-wave segments as described in the second embodiment, and all the wave segments arranged circumferentially in each group of double-wave segments are connected to form a single-layer double-wave support unit 201, and each support segment also includes a reinforcement layer double-wave support unit 202. The support ridge arrangement structure of the reinforcement layer double-wave support unit is similar to the support ridge arrangement structure of the single-layer double-wave support unit, and the connection between each support ridge 20a of the reinforcement layer double-wave support unit forms a vertex 20e, and each vertex 20e on both sides of the axial direction of the reinforcement layer double-wave support unit is respectively connected to the vertex 20e at the corresponding position of the single-layer double-wave support unit. In this embodiment, the structure of the single-layer double-wave support unit 201 can be the same as the support segment structure of the second embodiment, and the difference between the reinforced layer double-wave support unit 202 and the single-layer double-wave support unit 201 is that the reinforced layer double-wave support unit 202 is also a double-wave structure, but the double waves do not need to be connected, and the vertices 20e on both sides of the axial direction of the reinforced layer double-wave support unit 202 are integrally connected to the vertices on both sides of the axial direction of the single-layer double-wave support unit 201, thereby connecting the two layers of double-wave support structures into one.

[0046] The multiple support segments in the metal stent of the pulmonary artery stent in this embodiment are also wrapped by an isolation membrane composed of an inner film and multiple segments of outer films. The relevant structure of the isolation membrane is similar to that of the previous embodiment and will not be repeated here.

[0047] The pulmonary artery stent of this embodiment has better structural strength and can meet the requirements of greater vascular support strength.

[0048] Combined with Figure 1 The method and steps for using the pulmonary artery stent according to the embodiment of the present invention are as follows:

[0049] An instrument intervention channel is established in the femoral vein by means of a puncture needle, a guide wire, a catheter and a small puncture sheath. The intravascular intervention channel technology is used to introduce a catheter into the narrowed part of the blood vessel, and then selective angiography is performed to determine the narrowed part and the blood vessel size information. The angiography catheter is replaced with a guide wire (the guide wire is introduced and then the catheter is withdrawn). A balloon catheter pre-installed with the pulmonary artery stent of an embodiment of the present invention is introduced into the narrowed part of the blood vessel via the guide wire. The pre-installed pulmonary artery stent is expanded to the corresponding blood vessel size by expanding the balloon catheter to ensure that the pulmonary artery stent is fully expanded and fits on the blood vessel wall, and then the balloon pressure is released, and finally the balloon catheter is withdrawn from the body, the wound is sutured, and the operation is completed. At a later stage, the growth of the blood vessels is observed by follow-up. If the stent needs to be expanded to a larger size due to a large change in the size of the blood vessel, the operation can be performed again, and the stent can be further expanded by introducing a balloon.

[0050] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A pulmonary artery stent, characterized in that: include: Circumferentially expandable metal stents; An isolation membrane wrapping the metal stent to isolate the metal stent from the external environment, wherein the circumferential tensile strength of the isolation membrane is less than the axial tensile strength; The metal stent comprises: a plurality of stent segments; The isolation film comprises an inner film and a plurality of strip-shaped or cylindrical outer films; The inner film covers the inner surface of the metal stent, and each segment of the outer film is connected to the inner film and covers each segment of the stent respectively; Each of the stent segments is connected via the isolation membrane; The support segment is formed by a plurality of support edges connected end to end and arranged in a wave shape and surrounded along the arrangement direction; the support segment includes a plurality of ordinary edges and extended edges; each support segment has a plurality of ordinary edges provided with telescopic segments, and the plurality of telescopic segments in the same support segment are evenly distributed in the circumferential direction; Alternatively, the support segment comprises a plurality of groups of double wave segments arranged in the circumferential direction, and two of the double wave segments are symmetrically arranged; wherein each of the double wave segments is composed of a plurality of supporting edges connected end to end and arranged in a wave shape, and the supporting edges located at the connecting ends of the double wave segments and close to each other serve as connecting edges, and the connecting edges of any two groups of double wave segments adjacent in the circumferential direction are cross-connected; and the connecting edge of each wave segment has a telescopic section; At least one section of the outer film has a skirt, and a drug storage groove is formed between the skirt and the inner film.

2. The pulmonary artery stent according to claim 1, characterized in that: The isolation membrane is a polytetrafluoroethylene film and forms a smooth blood flow channel surface after wrapping the metal stent.

3. The pulmonary artery stent according to claim 1, characterized in that: The support edges of adjacent stent segments partially overlap axially.

4. The pulmonary artery stent according to claim 1, characterized in that: All the wave segments arranged along the circumferential direction in each group of double wave segments in each support segment are connected to form a single-layer double wave support unit, and each of the support segments also includes a reinforced layer double wave support unit; the support edge arrangement structure of the reinforced layer double wave support unit is similar to the support edge arrangement structure of the single-layer double wave support unit, and the connection between the support edges of the reinforced layer double wave support unit forms a vertex, and the vertices on both sides of the axial direction of the reinforced layer double wave support unit are respectively connected integrally with the vertices at the corresponding positions of the single-layer double wave support unit.

5. The pulmonary artery stent according to claim 1, characterized in that: A double-bend bridge structure is used between the wave segments to achieve the cross connection.

6. The pulmonary artery stent according to claim 1, characterized in that: The telescopic section is composed of a plurality of metal wires which are connected end to end and arranged in a wave shape.

7. The pulmonary artery stent according to any one of claims 1 to 6, characterized in that: The metal bracket is provided with a plurality of barbs distributed along the circumference.

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