WO2022022143A1 - 一种载膜支架 - Google Patents

一种载膜支架 Download PDF

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Publication number
WO2022022143A1
WO2022022143A1 PCT/CN2021/100498 CN2021100498W WO2022022143A1 WO 2022022143 A1 WO2022022143 A1 WO 2022022143A1 CN 2021100498 W CN2021100498 W CN 2021100498W WO 2022022143 A1 WO2022022143 A1 WO 2022022143A1
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WO
WIPO (PCT)
Prior art keywords
membrane structure
stent
membrane
proximal end
film
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PCT/CN2021/100498
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English (en)
French (fr)
Inventor
高小龙
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上海苏畅医疗科技有限公司
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Publication of WO2022022143A1 publication Critical patent/WO2022022143A1/zh

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
    • A61F2/06—Blood vessels
    • A61F2/07—Stent-grafts
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12—Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/12—Surgical instruments, devices or methods, e.g. tourniquets for ligaturing or otherwise compressing tubular parts of the body, e.g. blood vessels, umbilical cord
    • A61B17/12022—Occluding by internal devices, e.g. balloons or releasable wires
    • A61B17/12099—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder
    • A61B17/12109—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel
    • A61B17/12113—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel within an aneurysm
    • A61B17/12118—Occluding by internal devices, e.g. balloons or releasable wires characterised by the location of the occluder in a blood vessel within an aneurysm for positioning in conjunction with a stent
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
    • A61F2/06—Blood vessels
    • A61F2/07—Stent-grafts
    • A61F2002/075—Stent-grafts the stent being loosely attached to the graft material, e.g. by stitching
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2210/0014—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof using shape memory or superelastic materials, e.g. nitinol
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2210/00—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2210/0061—Particular material properties of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof swellable
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2250/00—Special features of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2250/0058—Additional features; Implant or prostheses properties not otherwise provided for
    • A61F2250/0096—Markers and sensors for detecting a position or changes of a position of an implant, e.g. RF sensors, ultrasound markers
    • A61F2250/0098—Markers and sensors for detecting a position or changes of a position of an implant, e.g. RF sensors, ultrasound markers radio-opaque, e.g. radio-opaque markers

Definitions

  • the invention relates to the field of medical devices, in particular to a film-carrying stent.
  • Aneurysm is a common cardiovascular and cerebrovascular disease, and once ruptured, the fatality rate is extremely high. Larger aneurysms have a higher risk of rupture, and even with conservative treatment, the ruptured aneurysm has a higher risk of re-rupture after stabilization.
  • Medical treatment is the basis. The treatment of aneurysms mainly includes surgical clipping of aneurysms and interventional endovascular treatment. Surgical operations have higher risks, greater trauma and more complications. With the development of interventional technology, the emergence of stents has greatly improved the efficacy of interventional treatment of intracranial aneurysms.
  • the main clinical stent technologies include: stent-assisted coil embolization, blood flow diversion device placement, and stent-graft placement.
  • Stent-assisted coil embolization can change the hemodynamic state at the aneurysm neck, change the curvature of the parent artery, and act as a "scaffold" for vascular endothelial growth.
  • Flow diverting devices can alter the intra-arterial hemodynamic state and induce intra-aneurysmal thrombus formation.
  • the stent-graft can isolate the blood flow in the aneurysm and induce thrombosis in the aneurysm.
  • the prior art vascular stents still have some drawbacks.
  • the metal coverage rate of a vascular stent refers to the metal coverage area in the stent accounting for the total stent area. proportion.
  • the Pipeline stent with a metal coverage rate of about 35% can be used for interventional therapy.
  • the metal coverage of the stent is too high, there will be problems of high radial tension and poor compliance; it may obstruct or even block the blood flow of the peripheral blood vessels, causing additional harm to the patient; the blood pressure at the proximal end of the aneurysm is very high, The mesh of the stent is prone to aneurysm rupture and bleeding under the continuous flow of blood flow.
  • the covered stents in the prior art can solve some of the above-mentioned problems of bare metal stents, but the inventors found new difficulties during the manufacturing process, which are mainly reflected in the following aspects: 1. It is difficult to process the covered metal stents ; Second, the thick film is difficult to load and transport.
  • the purpose of the present invention is to provide a film carrier stent, which can realize the application of the film carrier stent in tortuous blood vessels, improve the overall compliance of the film carrier stent, facilitate the loading and delivery of the film carrier stent, and fix the film structure only at the proximal end. , reducing the difficulty of the connection process of the film-carrying stent.
  • a film-carrying stent comprising:
  • bracket main body is a hollow grid structure
  • a membrane structure is provided inside the stent body, and the proximal end of the membrane structure is fixed on the stent body.
  • the processing difficulty of the membrane carrier stent is reduced, and the overall compliance of the membrane carrier stent can be improved at the same time, which is convenient for loading and delivery in the blood vessel, and the membrane structure is set Inside the stent body, it is convenient for the membrane structure to be close to the blood vessel wall under the flushing of blood, so as to form a blockage for the aneurysm.
  • a portion or all of the membrane structure tapers axially in the direction from the proximal end to the distal end of the membrane structure.
  • the effect of the cross-sectional size on the fluid pressure is different, which is more conducive to the flow of blood from the proximal end to the distal end, that is, from the end with a large cross-section to the end with a small cross-section. flow, while preventing blood from flowing into the interlayer between the membrane structure and the stent body.
  • the distal end of the membrane structure is fixed on the stent body, and the part of the membrane structure between the proximal end and the distal end is kept free on the stent body, preferably, the membrane structure
  • the diameter of the distal end of the stent is larger than the diameter of the stent body, so that the membrane structure forms a corrugated shape in the circumferential direction of the stent body.
  • the distal end of the membrane structure can be fixed with the stent body. At this time, the main part of the membrane structure is kept free on the stent body.
  • the membrane structure can also be The diameter of the distal end is larger than the diameter of the main body of the stent.
  • the distal end of the membrane structure When the blood flow is flushed, the distal end of the membrane structure will stick to the main body of the stent, and part of it will protrude to the grid on the main body of the stent to form wavy folds, thereby effectively preventing Blood enters the interlayer between the membrane structure and the stent body, and the folded portion may facilitate the blood to form a thrombus, thereby forming a occlusion of the aneurysm outlet.
  • the membrane structure is provided with a gap corresponding to the branch blood vessel, one end of the gap penetrates the distal end of the membrane structure, and the other end extends to the middle of the membrane structure or penetrates the membrane structure. the proximal end.
  • the membrane structure is provided with a gap corresponding to the branch blood vessel, through which the blood can enter the branch blood vessel without blocking the branch blood vessel.
  • one end of the gap penetrates the distal end of the membrane structure, The other end extends to the middle of the membrane structure or through the proximal end of the membrane structure, depending on the actual condition of the blood vessel.
  • the proximal end of the membrane structure and the stent body are sutured by suture, wherein the suture sutures a part or all of the proximal end of the membrane structure to fix the membrane
  • the suture is made of a developing material.
  • the proximal end of the membrane structure and the main body of the stent can be sutured by sutures, so that the proximal end of the membrane structure and the main body of the stent can be fixed.
  • the proximal end of the membrane structure can be fixed circumferentially.
  • the proximal end of the membrane structure can also be individually fixed.
  • the suture can be made of developing material, and the suture can be used to fix the proximal end of the membrane structure and the main body of the stent, and to display the proximal end of the membrane structure or the stent.
  • the role of the position of the stent body is the role of the position of the stent body.
  • the proximal end of the membrane structure is bonded to the stent body by an adhesive, and/or the proximal end of the membrane structure is prepared with a flocculent material and wrapped with the stent body to fix it.
  • the proximal end of the membrane structure and the stent body are bonded to the stent body by an adhesive, and/or the proximal end of the membrane structure is prepared with a flocculent material and wrapped with the stent body to fix it.
  • the proximal end of the membrane structure can be bonded to the main body of the stent through an adhesive, and the proximal end of the membrane structure can also be prepared with a flocculent material, so that the proximal end of the membrane structure can be wrapped around the flocculent material.
  • the fixation between the proximal end of the membrane structure and the stent body can also be achieved.
  • the membrane structure is made of a microporous membrane material, and the inner surface of the microporous membrane material is coated with a hydrophilic coating.
  • the membrane structure made of the microporous membrane material can facilitate drug loading in the micropores on the membrane material, and can reduce the material of the entire membrane-carrying stent to a certain extent, making the membrane-carrying stent easier to press and hold
  • the micropores of the membrane material play an important role in the endothelialization process of the membrane-loaded stent, and the hydrophilic coating can effectively reduce the thrombosis in the membrane-loaded stent, so that a smooth blood flow channel can be formed inside the membrane-loaded stent.
  • the stent body is provided with a first visualization mark for displaying the stent body, and the first visualization marks are distributed on the stent body along the axial direction of the stent body.
  • the first imaging markers distributed along the axial direction of the stent body are used to display the position and total length of the stent body in the blood vessel.
  • the stent main body is provided with a second visualization mark for displaying the membrane structure, and the second visualization mark is distributed along the axial direction of the stent main body in correspondence of the stent main body and the membrane structure. place.
  • the second visualization mark disposed on the stent body corresponding to the membrane structure is used to indicate the position of the membrane structure in the blood vessel, ensuring that the membrane structure at least covers the proximal end of the aneurysm.
  • the support body is provided with a third developing mark for displaying the gap on the membrane structure, and the third developing mark is distributed between the support body and the gap along the axial direction of the support body. the corresponding place.
  • the third visualization mark disposed on the stent body corresponding to the notch is used to indicate the position of the notch in the membrane structure in the blood vessel, so as to ensure that the notch in the membrane structure corresponds to the branch blood vessel.
  • the sealing effect of the membrane structure on the aneurysm can be used to reduce the mesh density on the stent main body, thereby reducing the metal coverage rate on the stent main body, and not only improving the stent main body.
  • the membrane structure is only fixed on the stent body through the proximal end, and the other parts of the stent body are
  • the main body of the stent remains in a free state, which reduces the processing difficulty of the membrane-loaded stent, and at the same time facilitates the fabrication of membrane structures of different shapes to adapt to different shapes of blood vessels. Some tortuous vessels can still have some degree of compliance.
  • Fig. 1 is a three-dimensional schematic diagram of a film-carrying stent of the present invention
  • Fig. 2 is the partial enlarged structural schematic diagram of the membrane structure of the present invention.
  • Fig. 3 is the structural representation of the microporous membrane material of the present invention.
  • Fig. 4 is the enlarged structure schematic diagram of A place in Fig. 3;
  • Fig. 5 is the structure schematic diagram that the membrane structure of the present invention is provided with one of the notch shapes
  • Fig. 6 is the structure schematic diagram that the membrane structure of the present invention is provided with another kind of notch shape
  • FIG. 7 is a schematic structural diagram of the membrane structure of the present invention made into a truncated cone.
  • a film-carrying stent is used in a blood vessel containing an aneurysm structure.
  • the film-carrying stent includes a stent body 1 and a membrane structure 2.
  • the stent body 1 is hollow inside and is hollow as a whole. It has a circular cross section, and meanwhile, the bracket body 1 is a grid-like structure, and both ends of the bracket body 1 are provided with openings 12 .
  • the stent body 1 includes an inflow section, an outflow section and an intermediate section, the inflow section and the outflow section are supported on the vessel wall, and the intermediate section corresponds to the position of the aneurysm.
  • the membrane structure 2 is arranged inside the stent body 1, the proximal end 21 (referring to the end close to the heart) of the membrane structure 2 is fixed on the stent body 1, and the other parts of the membrane structure 2 are kept free on the stent body 1 (refer to FIG. 2 ). ), that is, other parts of the membrane structure 2 are not fixed with the stent body 1 .
  • one end of the stent body 1 extends beyond the proximal end 21 of the membrane structure 2, and the other end extends beyond the distal end 22 of the membrane structure 2 (referring to the end away from the heart).
  • the stent body 1 When the stent-graft is released to the part with the aneurysm structure in the blood vessel through the microcatheter, the stent body 1 expands from the compressed state to adapt to the blood vessel, and adheres closely to the inner wall of the blood vessel, and blood circulates inside the stent-graft (as shown in Fig. 1 in the direction of the arrow). The inflow and outflow sections of the stent body 1 will be supported on the vessel wall accordingly. Under the flushing of blood flow with a certain blood pressure, the non-fixed part of the membrane structure 2 can better fit with the inner wall of the stent body 1 , thereby achieving the effect of isolating blood flow from entering the entrance of the aneurysm neck.
  • the part of the membrane structure 2 located at the aneurysm orifice will isolate the high-speed and high-pressure blood flow in the aorta from entering the false lumen where the aneurysm is located, thereby reducing the pressure in the false lumen and causing thrombosis, thereby filling the aneurysm. It prevents blood from entering the aneurysm and further enlarges the aneurysm.
  • the mesh 11 on the stent body 1 covers the aneurysm to change the local blood flow, thereby promoting the blood flow in the aneurysm to slow down the formation of thrombus, provide an attachment point for the regeneration of the intima of the blood vessel, and promote the remodeling of the aneurysm neck and the endothelium of the aneurysm. to achieve a healing effect.
  • the inventors found that although a part of blood flows from the dissection between the distal end 22 of the membrane structure 2 and the stent body 1 into the false lumen of the aneurysm because the distal end 22 of the membrane structure 2 is not fixed However, since the distal end 22 of the membrane structure 2 is close to the outlet of the aneurysm, this part of blood will not cause adverse effects on the aneurysm.
  • the inventors fix the membrane structure 2 by fixing the proximal end 21 in order to make the membrane-carrying stent still have good compliance and roaming ability in the tortuous blood vessel.
  • the proximal end 21 of the membrane structure 2 is fixed to the stent body 1, so that other parts of the membrane structure 2 are kept free on the stent body 1 (that is, not fixed with the stent body 1).
  • the film-loaded stent can reduce the metal coverage of the stent and improve the overall compliance.
  • the pressure on the stent body 1 becomes smaller, which improves the overall fatigue resistance and avoids the stent body 1. Broken and ruptured aneurysms.
  • the membrane structure 2 has a better blocking effect than the bare stent, it can better prevent blood from entering the aneurysm, and the blocking effect of the membrane structure 2 can be reduced.
  • the mesh density of the metal stent can reduce the metal coverage of the metal stent, so that the film-carrying stent has better compliance, and at the same time, it can ensure the radial tension and good adherence performance of the film-carrying stent.
  • the stent-graft in this embodiment is only fixed to the stent body 1 at the proximal end 21 of the membrane structure 2, so that the processing difficulty of the stent-graft can be reduced, and at the same time, it can be easily
  • the membrane structure 2 is processed into different shapes. Since the existing covered stent adopts the scheme of covering the stent skeleton and fixing the covering and the stent skeleton as a whole, the connection process of the covering is difficult, and the film layer is often very thick, which increases the number of coverings. The difficulty of crimping the stent, although it can block the aneurysm, is inconvenient for processing, and it is difficult to reduce the manufacturing cost of the stent graft.
  • the film carrier stent in this embodiment provides a completely different fixing solution from the existing film carrier stent, which not only reduces the difficulty of the connection process between the film structure 2 and the stent body 1, but also improves the load carrying capacity.
  • the compliance of the membrane stent enables the membrane stent to better adapt to tortuous blood vessels; it can also manufacture membrane structures 2 of different shapes in actual use, such as some special-shaped membrane structures 2, which can be left on the membrane structure 2.
  • the vacant part on the membrane structure 2 can face the branch blood vessel, so that the blood flow can enter other surrounding blood vessels through the vacant part.
  • a part or all of the membrane structure 2 is axially tapered in the direction from the proximal end 21 to the distal end 22 of the membrane structure 2 .
  • a part of the membrane structure 2 has a certain taper, or the whole of the membrane structure 2 presents a truncated hollow structure.
  • the cross-section of the pipe When the incompressible fluid moves in the pipe, in order to maintain the stability of the flow, the cross-section of the pipe will be designed with different sizes, so that the flow velocity in the small section of the pipe will be large, and the flow velocity in the large section will be small. According to Bernoulli's equation, the increase of the flow velocity is accompanied by the decrease of the fluid pressure, so the pressure in the pipe is small in the small section, and the pressure is large in the large section.
  • the membrane structure 2 is only fixedly connected at the proximal end 21, the membrane structure 2 can be processed into a shape with a certain taper, so that the cross-sectional area of the membrane structure 2 in the blood inflow section is larger than that in the blood inflow section.
  • the cross-sectional area of the membrane structure 2 in the outflow section is larger than that in the blood inflow section.
  • the membrane structure 2 can function as a "membrane valve".
  • the "membrane valve” is opened by flushing with blood, which can realize the function of the stent-graft, and can Reduce the difficulty in the connection process of the stent-graft.
  • this embodiment is more favorable for blood to flow from the inflow section to the outflow section, while preventing blood from flowing backward into the dissection between the membrane structure 2 and the stent body 1 and entering the false lumen of the aneurysm.
  • the membrane structure 2 near the distal end 22 is set as a truncated hollow structure, when the blood flows to the membrane structure 2 near the distal end 22, under the influence of the cross-sectional diameter, the blood at the distal end 22 of the membrane structure 2
  • the pressure will be lower than the blood pressure in other parts of the membrane structure 2 , so that the outflow of blood from the distal end 22 of the membrane structure 2 is facilitated.
  • the entire membrane structure 2 is set as a truncated hollow structure, and blood is affected by the cross-sectional diameter of the membrane structure 2 during the process of flowing from the proximal end 21 to the distal end 22 of the membrane structure 2, and is located in the membrane structure 2.
  • the blood pressure at the distal end 22 of the membrane structure 2 is lower than the blood pressure at the proximal end 21 of the membrane structure 2 , so that it is favorable for blood to flow from the proximal end 21 of the membrane structure 2 to the distal end 22 of the membrane structure 2 .
  • the distal end 22 of the membrane structure 2 can also be fixed, but only the main body part is not fixed. At this time, the membrane structure 2 is located between the proximal end 21 and the distal end 22. Parts remain free on the stent body 1 .
  • the diameter of the distal end 22 of the membrane structure 2 is larger than the diameter of the stent body 1 , so that the membrane structure 2 forms a wrinkled shape in the circumferential direction of the stent body 1 . It is formed by leaving a margin of material.
  • the membrane structure 2 can also be arranged outside the stent body 1 so that the membrane structure 2 covers the outer surface of the stent body 1 , when the membrane-loaded stent is released into the blood vessel, the membrane structure 2 closely adheres to the blood vessel wall, so that a better healing effect can be formed on the aneurysm.
  • the proximal end 21 of the membrane structure 2 in the stent-graft is fixed, and the main part is not fixed, so it is easier to process into different shapes and adapt to different aneurysms.
  • the membrane material can be a complete and regular piece, or can be made into other irregular shapes according to the shape and location of the aneurysm. If there is no bifurcated blood vessel at the aneurysm, the membrane structure 2 with a complete sleeve can be used, and the sleeve can cover the neck of the aneurysm. As shown in Figures 5 and 6, if there are bifurcated blood vessels at the aneurysm, part of the membrane material can be removed, or other shapes can be selected according to the anatomical structure.
  • FIG. 5 shows one of the shapes of the notch 23 , one end of the notch 23 penetrates the distal end 22 of the membrane structure 2 , and the other end extends to the middle of the membrane structure 2 .
  • FIG. 6 Another shape of the gap 23 is shown in FIG. 6 .
  • One end of the gap 23 penetrates the proximal end 21 of the membrane structure 2 and the other end penetrates the distal end 22 of the membrane structure 2 . adapted to the blood flow of branch vessels.
  • the notch 23 can occupy a superior arc or inferior arc on the radial cross-section of the membrane structure 2. Since the proximal end 21 of the membrane structure 2 has been fixed on the stent body 1, when the stent-graft is released to the After being inserted into the blood vessel and adapted to the blood vessel, the membrane structure 2 and the stent body 1 are in a relatively fixed state, that is, the membrane structure 2 will be stabilized on the stent body 1 , thereby blocking the aneurysm opening.
  • the density of the grids 11 on the stent body 1 corresponding to the notches 23 can be set to be smaller than the density of the grids 11 on the stent body 1 corresponding to the membrane structure 2, so that the gaps of the grids 11 on the stent body 1 are sufficient
  • the aneurysm opening can be occluded without impeding the flow of blood in the branch vessels.
  • the stent body 1 can be made of Nitinol, titanium alloy, cobalt-chromium alloy, MP35n, 316 stainless steel, L605, Phynox/Elgiloy, platinum-chromium, or other biocompatible materials known to those skilled in the art Made of metal.
  • the stent body 1 is made of shape memory alloy, but optionally, it also includes elastically or plastically deformable materials, such as balloon-expandable materials.
  • the stent body 1 is provided with a grid 11 structure, which can reduce the metal coverage as much as possible while ensuring the radial tension of the stent body 1 and good adherence performance.
  • the processing technology of the stent body 1 may be laser cutting of a pipe, wire weaving or welding, followed by heat treatment and shaping, and the stent body 1 has a grid-like structure after heat setting.
  • the radial force of the stent body 1 can be adjusted by adjusting the thickness of the cut tube and the diameter of the braiding wire.
  • the compliance of the stent body 1 can be optimized by adjusting the density of the grid-like structure of the stent body 1 .
  • the stent body 1 prepared by using the shape memory alloy has good compressibility, and the diameter of the stent body 1 can be compressed to enter into a blood vessel with a smaller diameter, so as to facilitate the compression state and Transitions between expanded states on release.
  • the stent-graft When the stent-graft is delivered to the lesion site, it can achieve self-expanding release to its uncompressed shape. Therefore, when performing vascular reconstruction, it is only necessary to select a film-carrying stent with appropriate length and diameter to be implanted into the arterial blood vessel according to the specific conditions of the hemangioma to be treated. After the stent reaches the lesion site, the step of balloon dilation is no longer required, and the operation is convenient.
  • the stent main body 1 is preferably a braided structure, for example, it can be braided by 8 to 256 braided wires, preferably between 12 and 64 braided wires.
  • the stent body 1 may be a straight cylindrical shape, or may be a "dumbbell shape" in which the diameters of both ends are larger than the diameter of the middle part.
  • the diameter of the two ends of the "dumbbell-shaped" stent body 1 is slightly larger than the diameter of the blood vessel.
  • the diameter of both ends of the stent body 1 is 2-6 mm, and the total length is 18-42 mm.
  • the membrane structure 2 is made of a microporous membrane material 3.
  • the membrane structure 2 is selected from a membrane material with low surface energy.
  • a membrane material with low surface energy For example, polytetrafluoroethylene in a bulk form can be selected.
  • Ethylene fluoride (ePTFE) ePTFE
  • ePTFE membrane is a polymer membrane material composed of polytetrafluoroethylene. This material is mainly composed of many nodes and the limit issued by the nodes. The nodes are connected with each other by crisscross fibers, which is conducive to cell level and transmembrane migration, and has good blood compatibility and tissue compatibility.
  • Capacitance good fatigue resistance, wear resistance, and elongation, can withstand most hydrolytic enzymes in the body, and can reduce blood coagulation through passive anticoagulation.
  • the micropores 31 on the ePTFE membrane can be used for drug loading, and on the other hand, the material of the entire membrane carrier can be reduced to a certain extent. , making it easier to crimp the film carrier for delivery.
  • micropores 31 of the membrane material are an important factor affecting the endothelialization of the film-carrying stent, and the micropores 31 of a certain size play an important role in the process of the endotheliumization of the film-carrying stent.
  • the inner surface of the microporous membrane material 3 is coated with a hydrophilic coating, which can effectively reduce the formation of thrombus in the film-carrying stent, so that a smooth blood flow channel can be formed inside the film-carrying stent, thereby reducing the stenosis of the film-carrying stent lumen. incidence.
  • the membrane material can be selected from non-degradable macromolecules and their polymers that have been biomodified or carry functional drugs, such as polyvinyl chloride (PU), polyethylene phthalate (PET), tetrafluoroethylene polymers (PTFE), etc.; or degradable polymer materials such as polylactic acid (PLLA or DLPLA), lactic acid-glycolic acid copolymer (PLGA), polyglycolic acid, polyglycolide, polylactide, polycaprolactone, polyethanol acid, etc.; or related copolymers or natural polymers such as collagen, gelatin, chitosan, fibrinogen, etc.
  • PU polyvinyl chloride
  • PET polyethylene phthalate
  • PTFE tetrafluoroethylene polymers
  • degradable polymer materials such as polylactic acid (PLLA or DLPLA), lactic acid-glycolic acid copolymer (PLGA), polyglycolic acid, polyglycolide, polylactide, poly
  • the thickness of the film material is 0.5 to 50 ⁇ m.
  • connection between the membrane structure 2 and the stent body 1 can be sutured, glued, wound, or the like.
  • the membrane structure 2 is only fixed to the stent body 1 at the proximal end 21 by means of suture
  • the suture thread 7 can be made of materials such as polypropylene, polyester, nylon thread and the like.
  • the suture section of the membrane structure 2 can be completely sutured in the circumferential direction, or incompletely sutured, and only fixed at individual points, that is, the suture 7 can suture a part of the proximal end 21 of the membrane structure 2, or the proximal end of the membrane structure 2. All the ends 21 are sutured, so that the fixation effect between the proximal end 21 of the membrane structure 2 and the stent body 1 can be achieved.
  • the suture 7 can simultaneously play the role of fixing the proximal end 21 of the membrane structure 2 and the stent body 1, and The role of indicating the proximal end 21 of the membrane structure 2 or the position of the stent body 1 .
  • the membrane structure 2 is only fixedly connected to the stent body 1 at the proximal end 21 by means of bonding, and the connection can be achieved by using medical adhesive bonding, hot melt bonding or electrospinning.
  • the membrane structure 2 is only fixedly connected to the stent body 1 by winding at the proximal end 21 , for example, the proximal end 21 of the membrane structure 2 is made of a floc-like material and wrapped around the stent body 1 .
  • the developing marks include a first developing mark 4 for displaying the bracket body 1 and a second developing mark 5 for displaying the membrane structure 2 .
  • the first imaging marker 4 is used to identify the position and total length of the stent body 1 in the blood vessel, and is distributed on the stent body 1 along the axial direction of the stent body 1. Materials such as gold, platinum, PtW alloy, tantalum or PtIr alloy can be selected.
  • the first imaging mark 4 may be an alloy ring wrapping the stent body 1, or may be an alloy wire-shaped wrapping the stent body 1 woven, which is not particularly limited in this embodiment.
  • the second development mark 5 is used to indicate the position of the membrane structure 2 in the blood vessel, to ensure that the membrane structure 2 can cover at least the proximal end of the aneurysm, so as to ensure that the membrane structure 2 can block most of the blood flow into the aneurysm, and at the same time, Try to avoid the membrane structure 2 covering the branch vessels.
  • the second visualization markers 5 are distributed along the axial direction of the stent body 1 at the corresponding positions of the stent body 1 and the membrane structure 2, and can be selected from materials such as gold, platinum, PtW alloy, tantalum or PtIr alloy.
  • the second visualization markers 5 are located at The boundary position of the membrane structure 2 indicates the precise position of the membrane structure 2 by wrapping the developing wire around the stent body 1 , or wrapping one or several sections of the stent body 1 with the developing wire, or welding the developing ring on the stent body 1 .
  • the development mark also includes a third development mark for displaying the gap 23 on the film structure 2.
  • the third visualization marks 6 are distributed along the axial direction of the stent body 1 at the corresponding positions of the gap 23 of the stent body 1 and the membrane structure 2 .
  • the third development mark 6 can be selected from gold, platinum, PtW alloy, tantalum or PtIr alloy, etc.
  • the third development mark 6 is located at the boundary position of the gap 23 on the membrane structure 2, and is wrapped around the stent body 1 by the development wire, or wrapped by the development wire.
  • One or several sections of the stent body 1 or the developing ring is welded on the stent body 1 to indicate the precise position of the notch 23 on the membrane structure 2 .
  • the film-carrying stent in this embodiment is compatible with each other and can be used together with a micro-catheter, a micro-guide wire, a push rod, and the like.
  • angiography was performed first to clarify the location, size, aneurysm neck range and distribution of branch vessels of the aneurysm. A stent of appropriate size was selected. The microcatheter was loaded with the stent in place. After observing the appropriate position of the imaging point, the stent was slowly released. Pay attention to fine-tuning the position of the stent to partially cover the aneurysm and keep the branch vessels. After the stent is released, angiography is performed to observe the isolation effect and the patency of the branch vessels, and the surgical instruments are withdrawn.
  • the membrane structure 2 is only fixed to the stent body 1 at the proximal end 21, which has the following advantages:
  • the pressure on the stent body 1 is reduced, which improves the overall fatigue resistance of the implant and avoids damage to the stent body 1 and aneurysm rupture.
  • the stent body 1 with lower metal coverage can be used for the carrier membrane part of the implant to improve the compliance of the implant.
  • the partially-covered stent-graft reduces the interference to other perforating arteries and increases the scope of application (compared with the full-coverage, the partial film-covered advantage).
  • the membrane structure 2 of the membrane-carrying stent is only fixed at the proximal end 21, which is easier to process into different shapes and adapt to different aneurysms.
  • the membrane structure 2 can be processed into a truncated cone shape, which is conducive to the flow of blood from the inflow section to the outflow section, while preventing the blood from flowing back into the interlayer between the membrane structure 2 and the stent body 1 .

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Abstract

一种载膜支架，包括：支架主体（1），支架主体（1）为中空网格状结构；膜结构（2），膜结构（2）设置在支架主体（1）的内部，膜结构（2）的近端（21）固定在支架主体（1）上。通过将膜结构（2）的近端（21）固定在支架主体（1）上，而使膜结构（2）的其他部分在支架主体上（1）保持游离状态，从而提高了载膜支架的顺应性，同时降低了载膜支架的连接工艺难度，便于加工不同形状的膜结构（2），以适应不同形状的血管。

Description

一种载膜支架 技术领域
本发明涉及医疗器械领域，尤指一种载膜支架。
背景技术
动脉瘤是常见的心脑血管疾病，一旦破裂则致死率极高。较大的动脉瘤破裂的风险更高，已破裂的动脉瘤即使保守治疗，稳定后再破裂的风险也较大，这类动脉瘤通常起病急，病程短，易造成不良预后。形成动脉瘤的病因较多，多与动脉硬化、高血压、肌纤维发育不良、免疫因素、遗传因素等相关，目前其发病机制尚不完全明确。针对动脉瘤的治疗方面尚没有完全统一的认识，内科治疗时是基础，对于动脉瘤的处理主要包括外科手术夹闭动脉瘤和介入手术腔内治疗。外科手术风险较高，创伤较大，并发症较多，随着介入技术的发展，支架的出现使介入治疗颅内动脉瘤的疗效大大提高。
目前临床上主要的支架技术包括：支架辅助弹簧圈栓塞术、血流导向装置置入术和覆膜支架置入术。支架辅助弹簧圈栓塞可以改变动脉瘤颈处的血流动力学状态、改变载瘤动脉曲度、起到血管内皮生长的“脚手架”的作用。血流导向装置可以改变动脉内血流动力学状态诱发动脉瘤内血栓形成。覆膜支架可以隔绝动脉瘤内血流诱发瘤内血栓形成。不过，发明人发现现有技术的血管支架仍具有一些缺陷。
在支架辅助弹簧圈栓塞介入手术过程中，需要通过微导管穿越支架网眼输送弹簧圈来填塞动脉瘤腔，微导管穿过支架空隙的难度很大、而且由于操作时易穿破血管组织而导致风险较高，而且成本也较高。动脉瘤栓塞术后存在延迟闭塞、复发和破裂的风险。血流导向装置置入术中，为改变动脉内血流诱发动脉瘤内血栓形成，希望支架具有较高的金属覆盖率，血管支架的金属覆盖率是指支架中的金属覆盖面积占支架总面积的比例。目前临床上可以选择使用金属覆盖率35％左右的Pipeline支架进行介入治疗。然而，支架的金属覆盖率太高会存在径向张力高，顺应性变差的问题；可能会妨碍甚至阻塞周边血管的血 流，而对患者造成额外伤害；动脉瘤近端的血压很大，支架的网孔在血流的持续冲刷下容易发生动脉瘤破裂出血等等。
现有技术中的覆膜支架可以解决上述金属裸支架的部分问题，但是发明人在制作加工过程中又发现了新的难题，主要体现在以下方面：一、在金属支架上覆膜加工难度大；二、覆膜较厚难以装载和输送。
发明内容
本发明的目的是提供一种载膜支架，实现载膜支架在迂曲血管中的适用，提高了载膜支架的整体顺应性，便于载膜支架的装载和输送，同时仅在近端固定膜结构，降低了载膜支架的连接工艺难度。
本发明提供的技术方案如下：
一种载膜支架，包括：
支架主体，所述支架主体为中空网格状结构；
膜结构，所述膜结构设置在所述支架主体的内部，所述膜结构的近端固定在所述支架主体上。
本方案中，通过将膜结构的近端固定在支架主体上，降低了载膜支架的加工难度，同时可以提高载膜支架整体的顺应性，便于装载和在血管中输送，并且将膜结构设置在支架主体的内部，便于膜结构在血液的冲刷下紧贴血管壁，从而对动脉瘤形成封堵。
进一步优选地，所述膜结构的一部分或全部从所述膜结构的近端到远端的方向上轴向地渐缩。
本方案中，通过将膜结构的一部分或全部设置成圆台形，利用截面大小对流体压力的影响不同，更有利于血液从近端向远端流动，即从截面大的一端向截面小的一端流动，同时可以防止血液流入膜结构与支架主体之间的夹层。
进一步优选地，所述膜结构的远端固定在所述支架主体上，所述膜结构位于近端与远端之间的部分在所述支架主体上保持自由状态，优选地，所述膜结构的远端直径大于所述支架主体的直径，使所述膜结构在所述支架主体的周向上形成褶皱状。
本方案中，针对血压较小的使用情况，可以将膜结构的远端与支架主体进 行固定，此时，膜结构的主体部分在支架主体上保持游离状态，优选地，还可以使膜结构的远端直径大于支架主体的直径，当在血流冲刷下，膜结构的远端会紧贴在支架主体上，而一部分在向支架主体上的网格凸出，形成波浪形褶皱，从而有效防止血液进入膜结构与支架主体之间的夹层，并且褶皱部分可以有利于血液形成血栓，从而形成对动脉瘤出口的封堵。
进一步优选地，所述膜结构上设置有用于与分支血管相对应的缺口，所述缺口的一端贯穿所述膜结构的远端，另一端延伸至所述膜结构的中部或贯穿所述膜结构的近端。
本方案中，膜结构上设置有与分支血管相对应的缺口，通过缺口可以使血液进入到分支血管中，而不会对分支血管造成封堵，同时，缺口的一端贯穿膜结构的远端，另一端延伸至膜结构的中部或贯穿膜结构的近端，这依据血管的实际情况而定。
进一步优选地，所述膜结构的近端与所述支架主体之间通过缝合线进行缝合，其中，所述缝合线对所述膜结构的近端的一部分或全部进行缝合，以固定所述膜结构的近端与所述支架主体，优选地，所述缝合线采用显影材料制作而成。
本方案中，膜结构的近端与支架主体之间可以通过缝合线进行缝合，从而将膜结构的近端与支架主体进行固定，在固定时，可以对膜结构的近端进行周向固定，也可以对膜结构的近端进行个别固定，同时，缝合线可以采用显影材料制作而成，可以通过缝合线起到固定膜结构的近端和支架主体的作用，以及显示膜结构的近端或支架主体的位置的作用。
进一步优选地，所述膜结构的近端通过粘合剂与所述支架主体进行粘接，和/或所述膜结构的近端采用絮状材料制备且与所述支架主体进行缠绕，以固定所述膜结构的近端与所述支架主体。
本方案中，膜结构的近端可以通过粘合剂与支架主体进行粘接，还可以将膜结构的近端采用絮状材料制备，这样，膜结构的近端便可通过絮状材料缠绕在支架主体上，同样可以实现膜结构的近端与支架主体之间的固定。
进一步优选地，所述膜结构采用微孔膜材制作而成，且所述微孔膜材的内 表面涂有亲水涂层。
本方案中，通过微孔膜材制作而成的膜结构可以方便在膜材上的微孔进行载药，而且可以在一定程度上减少整个载膜支架的材料，让载膜支架更容易压握输送，同时，膜材微孔对载膜支架的内皮化过程具有重要作用，亲水涂层可以有效减少载膜支架内血栓形成，使载膜支架内部能够形成通畅的血流通道。
进一步优选地，所述支架主体上设置有用于显示所述支架主体的第一显影标识，所述第一显影标识沿所述支架主体的轴向分布在所述支架主体上。
本方案中，沿支架主体轴向分布的第一显影标识用于显示支架主体在血管内的位置和总长度。
进一步优选地，所述支架主体上设置有用于显示所述膜结构的第二显影标识，所述第二显影标识沿所述支架主体的轴向分布在所述支架主体与所述膜结构的对应处。
本方案中，设置在支架主体上与膜结构的对应处的第二显影标识用于指示膜结构在血管中的位置，确保膜结构至少覆盖动脉瘤的近端。
进一步优选地，所述支架主体上设置有用于显示所述膜结构上的缺口的第三显影标识，所述第三显影标识沿所述支架主体的轴向分布在所述支架主体与所述缺口的对应处。
本方案中，设置在支架主体上与缺口的对应处的第三显影标识用于指示膜结构的缺口在血管中的位置，确保膜结构的缺口与分支血管相对应。
本发明的技术效果在于：
本发明通过在支架主体上设置膜结构，从而利用膜结构对动脉瘤的封堵作用，可以降低支架主体上的网格密度，从而降低了支架主体上的金属覆盖率，不仅提高了支架主体的柔顺性，而且还可以保证支架主体的径向张力及良好的贴壁性能，便于载膜支架的装载和输送；同时膜结构仅通过近端固定在支架主体上，而使支架主体的其他部分在支架主体上保持游离状态，从而降低了载膜支架的加工难度，同时便于制作不同形状的膜结构，以适应不同形状的血管，膜结构和支架主体有一定程度的相互位移，使得载膜支架在一些迂曲的血管中依然能够具有一定程度的顺应性。
附图说明
下面结合附图和具体实施方式对本发明作进一步详细说明：
图1是本发明的一种载膜支架的立体结构示意图；
图2是本发明的膜结构处的局部放大结构示意图；
图3是本发明的微孔膜材的结构示意图；
图4是图3中A处的放大结构示意图；
图5是本发明的膜结构上设置有其中一种缺口形状的结构示意图；
图6是本发明的膜结构上设置有另外一种缺口形状的结构示意图；
图7是本发明的膜结构制作成圆台形的结构示意图。
附图标号说明：
1.支架主体，11.网格，12.开口，2.膜结构，21.近端，22.远端，23.缺口，3.微孔膜材，31.微孔，4.第一显影标识，5.第二显影标识，6.第三显影标识，7.缝合线。
具体实施方式
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
作为一个具体实施例，如图1所示，一种载膜支架，用在包含动脉瘤结构的血管中，该载膜支架包括支架主体1和膜结构2，支架主体1内部中空，整体呈中空并具有圆形的截面，同时，支架主体1为网格状结构，支架主体1的两端为开口12设置。支架主体1包括流入段、流出段和中间段，流入段和流出段支撑在血管壁上，中间段与动脉瘤的位置相对应。膜结构2设置在支架主体1的内部，膜结构2的近端21(指靠近心脏的一端)固定在支架主体1上，膜结构2的其他部分在支架主体1上保持自由状态(参阅图2)，即膜结构2的其他部分没有与支架主体1进行固定。可选地，支架主体1的一端超出膜结构2的近端21，另一端超出膜结构2的远端22(指远离心脏的一端)。
当载膜支架通过微导管释放至血管中具有动脉瘤结构的部位时，支架主体1从压缩状态膨胀以适应血管，并紧贴在血管的内壁上，血液在载膜支架的内部流通(如图1中的箭头方向所示)。支架主体1的流入段和流出段会相应地支撑在血管壁上。在一定血压的血流的冲刷下，膜结构2的非固定部分能较好地与支架主体1的内壁贴合，从而实现隔绝血流进入动脉瘤瘤颈入口的效果。此时，膜结构2位于动脉瘤口处的部分会隔绝主动脉内高速、高压血流进入动脉瘤所在的假腔，从而使假腔内压力下降，血栓形成，从而对动脉瘤起到一个填塞的作用，阻止血液进入到动脉瘤中而造成动脉瘤的进一步增大。同时，支架主体1上的网格11覆盖瘤口而改变局部血流，从而促进瘤腔内血流减慢形成血栓，为血管内膜再生提供附着点，促进动脉瘤的瘤颈重塑和内皮化以达到治愈效果。
同时，对于将膜结构2固定在支架主体1内的载膜支架，由于膜结构2不会直接与输送装置接触，从而不会在膜结构2的表面上形成较大的摩擦力而影响载膜支架的压握和释放。当将载膜支架释放至血管中后，由于膜结构2仅在近端21与支架主体1进行固定，因此，在膜结构2的远端22，会有一部分血液沿着膜结构2与支架主体1之间的缝隙向动脉瘤的假腔之中流动。对于这一部分血液，发明人发现尽管会有一部分血液由于膜结构2的远端22没有固定，而从膜结构2的远端22与支架主体1之间的夹层向动脉瘤的假腔之中流动，但是由于膜结构2的远端22靠近动脉瘤出口处，因此，这一部分血液对动脉瘤并不会造成不利影响。这是因为，血液在从膜结构2的远端22与支架主体1之间的缝隙向动脉瘤的假腔流动时，由于膜结构2的近端21已经封堵在动脉瘤的入口处，因此，在动脉瘤的入口处，并不会有血液形成流动通道，也就不会使动脉瘤进一步增大。同时，由于这一部分血液停留在膜结构2的远端22与支架主体1之间的夹层中，也会促进夹层内的血栓形成，有利于动脉瘤的治愈。
现有的覆膜支架将覆膜结构的整体与支架骨架进行固定，这样虽然能够较好地对动脉瘤进行封堵，但是发明人在制作加工过程中发现由于覆膜结构的整体固定，影响了支架骨架的顺应性，使得现有的覆膜支架在血管中的顺应性和 游走能力均变差。因此，发明人为了使载膜支架能够在迂曲的血管中依然具有较好的顺应性和游走能力，采取近端21固定的方式对膜结构2进行固定。
本实施例中通过将膜结构2的近端21与支架主体1进行固定，从而使得膜结构2的其他部分在支架主体1上保持游离状态(即与支架主体1没有进行固定)，这样，膜结构2和支架主体1有一定程度的相互位移，使得载膜支架具有较好的顺应性和在血管内游走的能力，尤其是在一些迂曲的血管内依然能够保持一定程度的顺应性，增加载膜支架的贴壁性能。
相对于金属裸支架：载膜支架可以降低支架的金属覆盖率，提高整体的顺应性，且载膜后，支架主体1受到的压强变小，提高了整体的耐疲劳性，避免了支架主体1破损和动脉瘤破裂。通过在支架主体1上载膜，由于膜结构2相比于裸支架具有更好的封堵作用，能够更好地起到防止血液进入动脉瘤中的作用，通过膜结构2的封堵效果可以降低金属支架的网孔密度，从而降低金属支架的金属覆盖率，使得载膜支架具有更好的顺应性，同时可以保证载膜支架的径向张力及良好的贴壁性能。
同时，相比于现有的覆膜支架：本实施例中的载膜支架仅在膜结构2的近端21与支架主体1进行固定，这样，可以降低载膜支架的加工难度，同时可以方便将膜结构2加工成不同形状。由于现有的覆膜支架采用在支架骨架上覆膜并将覆膜与支架骨架进行整体固定的方案，因此，覆膜的连接工艺难度大，并且膜层往往很厚，这样又增加了覆膜支架压握的难度，虽然能够起到对动脉瘤封堵的作用，但是不便于进行加工，难以降低覆膜支架的制造成本。
综上所示，通过本实施例中的载膜支架提供了一种与现有覆膜支架完全不同的固定方案，不仅降低了膜结构2与支架主体1之间的连接工艺难度，提高了载膜支架的顺应性，使得载膜支架能够更好地适应迂曲的血管；而且还能够在实际使用中制造不同形状的膜结构2，例如一些异型的膜结构2，可以在膜结构2上留出一些空缺的部分，使载膜支架释放至血管中时，膜结构2上的空缺部分可以对着分支血管，让血流能够通过空缺部分进入周边其他血管。
本实施例中，膜结构2的一部分或全部从膜结构2的近端21到远端22的方向上轴向地渐缩。这样，就使膜结构2的一部分具有一定的锥度， 或者膜结构2的全部均呈现为圆台形的中空结构。
当不可压缩的流体在管中运动时，为了维持流量的稳定，会将管的截面设计为不同大小，这样，会使得管中截面小处流速大，截面大处流速小。根据伯努利方程，流速的增大伴随流体压力的降低，因此管中截面小处压力小，截面大处压力大。
基于上述原理，在本实施例中，因为膜结构2仅仅在近端21固定连接，所以膜结构2可以加工成具有一定锥度的形状，让处于血液流入段的膜结构2的截面积大于处于血液流出段的膜结构2的截面积。
这样，就使膜结构2能够起到“膜阀”的效果，当将载膜支架释放至血管中后，利用血液的冲刷，把“膜阀”打开，可以实现覆膜支架的功能，又可以降低覆膜支架连接工艺上的困难。如图6所示，该实施方式更有利于血液从流入段向流出段流动，同时防止血液反向流入膜结构2与支架主体1之间的夹层，而进入到动脉瘤的假腔之中。
例如，将膜结构2靠近远端22处设置为圆台形中空结构，当血液流动至膜结构2靠近远端22处便会在截面直径大小的影响下，膜结构2的远端22处的血液压力会小于膜结构2的其他部分的血液压力，这样，就会有利于血液从膜结构2的远端22流出。
或如，将膜结构2的全部设置为圆台形中空结构，血液在从膜结构2的近端21流动至远端22的过程中，受到膜结构2的截面直径大小的影响，位于膜结构2的远端22的血压小于位于膜结构2的近端21的血压，这样，就会有利于血液从膜结构2的近端21流向膜结构2的远端22。
其中，为了防止在膜结构2的远端22出现内漏，只需控制膜结构2的腔壁锥度，使得膜结构2的远端22边缘靠近支架主体1的内表面，从而控制膜结构2的远端22边缘与动脉瘤瘤腔之间的缝隙。这时，尽管会有一部分血液从该缝隙中进入动脉瘤瘤腔中，如上所述，由于膜结构2的远端22边缘对应的是动脉瘤的出口，因此，仍然不会对动脉瘤造成不利影响。
针对血压较小的使用情况，在近端21固定的前提下，膜结构2的远 端22也可以固定，仅主体部分不固定，此时膜结构2位于近端21和远端22之间的部分在支架主体1上保持游离状态。
本实施例中，膜结构2的远端22直径大于支架主体1的直径，使膜结构2在支架主体1的周向上形成褶皱状，这种褶皱状结构是由于在膜结构2的远端22材料留出余量而形成的。
当对膜结构2进行固定时，膜结构2远端22的部分材料向支架主体1的网孔中凸出，而发生弯曲，从而在膜结构2的远端22会形成波浪形的褶皱状，从而防止血液进入膜结构2与支架主体1之间的夹层，并且通过这些褶皱可以在膜结构2的远端22形成血栓，以对膜结构2的远端22与支架主体1之间的夹层进行填塞，可以有效防止血液出现内漏的情况。
需要说明的是，对于将膜结构2的近端21与远端22同时进行固定的载膜支架，膜结构2也可以布置在支架主体1的外部，使膜结构2覆盖支架主体1的外表面，当将载膜支架释放至血管中后，膜结构2与血管壁贴覆严密，从而能够对动脉瘤形成较好的治愈效果。
相对于传统的覆膜支架：载膜支架中的膜结构2近端21固定，主体部分不固定，更易于加工成不同的形状，适应不同的动脉瘤。膜材可以为完整有规则的一整块，也可以根据动脉瘤形状和位置做成其他不规则形状。若动脉瘤处无分叉血管，可以选用完整袖筒的膜结构2，袖筒能覆盖动脉瘤颈部即可。如图5和图6所示，若动脉瘤处有分叉血管，可以选用去掉部分膜材，或者根据解剖结构，选用其他的形状。
如上所述，由于膜结构2与支架主体1之间的固定方式为膜结构2的近端21固定在支架主体1上，因此，可以方便将膜结构2制作成异型，即在膜结构2上留出缺口23部分，这些缺口23部分可以适应分支血管的血液流通。具体地，图5中显示了其中一种缺口23的形状，缺口23的一端贯穿膜结构2的远端22，另一端延伸至膜结构2的中部。图6中显示了另外一种缺口23的形状，缺口23的一端贯穿膜结构2的近端21，另一端贯穿膜结构2的远端22，在对动脉瘤形成封堵的同时，能够较好地适应分支血管的血液流通。
需要说明的是，缺口23可以在膜结构2的径向截面上占据优弧或劣弧，由于已经将膜结构2的近端21固定在支架主体1上，因此，当将载膜支架释放至血管中并适应血管后，膜结构2与支架主体1之间处于相对固定的状态，即膜结构2会稳定在支架主体1上，从而起到对动脉瘤口的封堵作用。
另外，可以将支架主体1上与缺口23对应处的网格11密度设置成小于支架主体1上与膜结构2对应处的网格11密度，这样，使得支架主体1上的网格11空隙足以允许血液通过，可以在封堵动脉瘤口的同时不会妨碍血液在分支血管中流通。
本实施例中，支架主体1可以采用如镍钛诺、钛合金、钴铬合金、MP35n、316不锈钢、L605、Phynox/Elgiloy、铂铬，或如本领域技术人员已知的其它生物相容性金属制成。优选地，支架主体1采用形状记忆合金制备而成，但是可选地，也包括可弹性或可塑性变形的材料，如球囊可扩张的材料。支架主体1上设置有网格11结构，可以在尽量减少金属覆盖率的同时，保证支架主体1的径向张力及良好的贴壁性能。支架主体1的加工工艺可以为管材激光切割、丝线编织或焊接，后续进行热处理定型而成，支架主体1热定型后为网格状结构。支架主体1的径向力可以通过调整切割管材的厚度、编织用丝线的直径来进行调节。支架主体1的顺应性可以通过调节支架主体1的网格状结构的密度来进行优化。
其中，采用形状记忆合金所制备的支架主体1具有很好的可压缩性能，能够将支架主体1直径压小以进入直径较小的血管中，这样，方便载膜支架在输送时的压缩状态和释放时的膨胀状态之间转换。
当输送载膜支架达到病灶部位时，能实现自膨胀释放至未受压缩前的形状。因此在进行血管重建时，只需根据待治疗血管瘤的具体情况，选择长度直径合适的载膜支架植入动脉血管即可，支架到达病灶部位后不再需要球囊扩张的步骤，操作方便。
进一步地，支架主体1优选为编织结构，例如可由8至256根编织丝编织而成，优选编织丝介于12～64根之间。
支架主体1可以为直筒型，也可以为两端部的直径大于中间部分直径 的“哑铃状”。“哑铃状”的支架主体1两端部的直径略大于血管直径，在支架主体1自膨胀释放后，支架主体1的两端部完全贴附于血管壁，从而保证载膜支架能够紧贴在血管壁上。
具体地，支架主体1两端部的直径为2～6㎜，总长度为18～42㎜。
本实施例中，如图3所示，膜结构2采用微孔膜材3制作而成，具体地，膜结构2选择具有低的表面能的膜材，例如，可以选择膨体形态的聚四氟乙烯(ePTFE)，ePTFE膜是一种高分子膜性材料，由聚四氟乙烯构成。这种材料主要由许多结点和结点发出的限位构成，结点之间通过纵横交错的纤维相互联结，从而有利于细胞水平和跨膜迁移，具有较好的血液相容性和组织相容性，同时具有良好的耐疲劳性、耐磨损性、延伸性，能够耐受体内大多数水解酶，可通过被动抗凝来降低血液的凝固。同时，如图4所示，利用ePTFE膜材上的微孔31，一方面，可以利用膜材上的微孔31进行载药，另一方面，可以在一定程度上减少整个载膜支架的材料，让载膜支架更容易压握输送。而且，膜材的微孔31是影响载膜支架内皮化的重要因素，一定大小的微孔31在载膜支架内皮化的过程中具有重要作用。
同时，在微孔膜材3的内表面涂有亲水涂层，可以有效减少载膜支架内血栓形成，使载膜支架内部能够形成通畅的血流通道，从而降低载膜支架管腔狭窄的发生率。
另外，膜材可选择经过生物修饰或携带功能性药物的不可降解高分子及其聚合物，例如聚氯乙烯(PU)、聚苯二甲酸乙二醇酯(PET)、四氟乙烯聚合物(PTFE)等；或可降解高分子材料，例如聚乳酸(PLLA或DLPLA)、乳酸-羟基乙酸共聚物(PLGA)、聚乙醇酸、聚乙交酯、聚丙交酯、聚己内酯、聚乙醇酸等；或相关共聚物或天然聚合物，如胶原蛋白、明胶、壳聚糖、纤维蛋白原等。
具体地，膜材的厚度为0.5～50μm。
具体地，膜结构2与支架主体1之间的连接方式可以为缝合、粘合、缠绕等。
例如，膜结构2仅在近端21通过缝合的方式与支架主体1固定，缝合线7 可采用如聚丙烯、聚酯、尼龙线等材料制备而成。膜结构2的缝合段可以为周向完全缝合，也可以为不完全缝合，仅个别点固定，即缝合线7可以对膜结构2的近端21的一部分进行缝合，或者对膜结构2的近端21的全部进行缝合，都可以实现膜结构2的近端21与支架主体1之间的固定效果。
进一步地，如果选用可以显影的材料制备缝合线7，如黄金、铂金、PtW合金、钽或PtIr合金等，则缝合线7可以同时起到固定膜结构2的近端21和支架主体1，以及指示膜结构2的近端21或支架主体1位置的作用。
再如，膜结构2仅在近端21通过粘接的方式与支架主体1固定连接，可以选用医用胶粘接，热熔粘或者静电纺丝的方式来实现连接。
或如，膜结构2仅在近端21通过缠绕的方式与支架主体1固定连接，例如，将膜结构2的近端21做成絮状材料，缠绕在支架主体1上。
手术中，判断载膜支架是否到达病灶部位需要一定的参考物，一般通过显影来观察支架的释放状态。具体地，显影标识包括用于显示支架主体1的第一显影标识4和用于显示膜结构2的第二显影标识5。第一显影标识4用于标识支架主体1在血管内的位置和总长度，沿支架主体1的轴向分布在支架主体1上，可选择黄金、铂金、PtW合金、钽或PtIr合金等材料，第一显影标识4可以为合金环包裹支架主体1，也可以为合金丝状缠绕支架主体1编织而成，对此本实施例不做特殊的限定。
第二显影标识5用于指示膜结构2在血管中的位置，确保膜结构2可以至少覆盖动脉瘤的近端，这样才能保证膜结构2可以阻挡大部分的血流进入动脉瘤中，同时，尽量避免膜结构2覆盖到分支血管上。
具体地，第二显影标识5沿支架主体1的轴向分布在支架主体1与膜结构2的对应处，可选择黄金、铂金、PtW合金、钽或PtIr合金等材料，第二显影标识5位于膜结构2的边界位置，通过显影丝缠绕支架主体1，或者显影丝包裹支架主体1的一段或者几段，或者显影环焊接在支架主体1上，来指示膜结构2的精确位置。
进一步地，针对由异型的膜结构2形成的载膜支架，即在膜结构2上设置有缺口23的载膜支架，显影标识还包括用于显示膜结构2上的缺口23的第三 显影标识6，第三显影标识6沿支架主体1的轴向分布在支架主体1与膜结构2的缺口23对应处。第三显影标识6可选择黄金、铂金、PtW合金、钽或PtIr合金等材料，第三显影标识6位于膜结构2上的缺口23的边界位置，通过显影丝缠绕支架主体1，或者显影丝包裹支架主体1的一段或者几段，或者显影环焊接在支架主体1上，来指示膜结构2上的缺口23的精确位置。
本实施例中的载膜支架与微导管、微导丝、推送杆等可相互兼容，配合使用。在植入前，首先进行造影，明确动脉瘤的位置、大小、瘤颈范围及分支血管的分布状况，选择合适规格的支架，微导管装载支架到位，观察显影点位置合适后缓慢释放支架，同时注意微调支架位置部分覆盖动脉瘤，并保留分支血管，解脱后再造影观察隔绝效果及分支血管通畅情况，退出手术器械。
本发明的载膜支架中，膜结构2仅在近端21与支架主体1固定，具有以下优点：
1、与金属裸支架相比，支架主体1部分载膜后，支架主体1受到的压强变小，提高了植入物整体的耐疲劳性，避免了支架主体1破损和动脉瘤破裂。
2、植入物载膜部分可用采用金属覆盖率较低的支架主体1，提高植入物的顺应性。
3、与全部覆膜的覆膜支架相比，部分载膜的载膜支架降低了对其它穿支动脉的干涉，适用范围增加(与全部覆膜相比，部分载膜的优点)。
4、载膜支架的膜结构2仅在近端21固定，更易于加工成不同的形状，适应不同的动脉瘤。
5、如图7所示，膜结构2可以加工成圆台形，有利于血液从流入段向流出段流动，同时防止血液反向流入膜结构2与支架主体1之间的夹层。
以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。

Claims (10)

  1. 一种载膜支架，其特征在于：包括：
    支架主体，所述支架主体为中空网格状结构；
    膜结构，所述膜结构设置在所述支架主体的内部，所述膜结构的近端固定在所述支架主体上。
  2. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述膜结构的一部分或全部从所述膜结构的近端到远端的方向上轴向地渐缩。
  3. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述膜结构的远端固定在所述支架主体上，所述膜结构位于近端与远端之间的部分在所述支架主体上保持自由状态，优选地，所述膜结构的远端直径大于所述支架主体的直径，使所述膜结构的远端在所述支架主体的周向上形成褶皱状。
  4. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述膜结构上设置有用于与分支血管相对应的缺口，所述缺口的一端贯穿所述膜结构的远端，另一端延伸至所述膜结构的中部或贯穿所述膜结构的近端。
  5. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述膜结构的近端与所述支架主体之间通过缝合线进行缝合，其中，所述缝合线对所述膜结构的近端的一部分或全部进行缝合，以固定所述膜结构的近端与所述支架主体，优选地，所述缝合线采用显影材料制作而成。
  6. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述膜结构的近端通过粘合剂与所述支架主体进行粘接，和/或所述膜结 构的近端采用絮状材料制备且与所述支架主体进行缠绕，以固定所述膜结构的近端与所述支架主体。
  7. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述膜结构采用微孔膜材制作而成，且所述微孔膜材的内表面涂有亲水涂层。
  8. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述支架主体上设置有用于显示所述支架主体的第一显影标识，所述第一显影标识沿所述支架主体的轴向分布在所述支架主体上。
  9. 根据权利要求1所述的一种载膜支架，其特征在于：
    所述支架主体上设置有用于显示所述膜结构的第二显影标识，所述第二显影标识沿所述支架主体的轴向分布在所述支架主体与所述膜结构的对应处。
  10. 根据权利要求4所述的一种载膜支架，其特征在于：
    所述支架主体上设置有用于显示所述膜结构上的缺口的第三显影标识，所述第三显影标识沿所述支架主体的轴向分布在所述支架主体与所述缺口的对应处。
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CN209107678U (zh) * 2018-05-30 2019-07-16 杭州唯强医疗科技有限公司 血管覆膜支架
CN110236750A (zh) * 2019-06-19 2019-09-17 邵明华 一种颅内动脉瘤隔绝支架
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CN203861386U (zh) * 2014-06-08 2014-10-08 高峰 部分覆膜血管支架
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CN212592564U (zh) * 2020-07-29 2021-02-26 上海畅达医疗科技有限公司 一种载膜支架

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