Covered stent for treating aortic aneurysm disease

Abstract

The utility model discloses a covered stent capable of being used for treating aortic aneurysm diseases, which relates to the technical field of medical instruments and comprises a self-expanding stent, a clamping piece is fixedly connected to the waist line position of an expanding portion of the self-expanding stent, and the clamping piece is made of super-elastic memory alloy. A mode of combining radial force anchoring and structure anchoring is adopted, a part of an anchoring piece is changed into a clamping piece from a traditional barb, the stent moves downwards after arriving at a designed position, the anchoring piece is unfolded and fixed on small blood vessels on two sides, meanwhile, the upper end of the clamping piece is self-expanded and unfolded, double anchoring is carried out, displacement of the stent is avoided, and the stability of the stent is improved. A self-expanding stent is adopted for supporting and an elastic clamping piece and a native blood vessel are clamped for fixing, additional damage is avoided, meanwhile, double-layer polyurethane films are adopted for covering, the anti-leakage capacity is improved while the flexibility is guaranteed, the blood vessel can be prevented from being damaged, and stable support is provided.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a covered stent that can be used to treat aortic aneurysm disease. Background Technology

[0002] Thoracoabdominal aortic aneurysms refer to aneurysmal dilatations of the aorta that simultaneously involve the thoracic and abdominal segments or other important blood vessels within the abdominal cavity, posing a significant threat to life. Minimally invasive surgery primarily involves inserting a covered stent via catheter to the lesion site, releasing and fixing the stent, isolating the lesion, reconstructing the vascular lumen, thereby reducing pressure at the tumor site, preventing tumor rupture, and ultimately achieving the therapeutic goal.

[0003] In existing technologies, the main fixation method for mainstream covered stents is barbed anchoring. If the distance is misjudged or plaque is present in the blood vessel, it can easily cause vascular damage. Furthermore, the outer layer of the covering is connected to the bare stent and the branch stent by sintering or suturing, which can easily lead to leakage in the constructed blood cavity. Due to the performance issues of the covering, it is also prone to damage, resulting in reduced strength and poor continuity. At the same time, the membranes used on the stents in existing technologies are mostly ePTFE porous membranes with smooth surfaces, which cannot be skinned in a short time. Moreover, ePTFE membranes have stress relaxation characteristics. If a tiny crack is caused during the production process, it can easily expand and tear, impacting the diseased area of ​​the outer layer and failing to reconstruct the cavity. Utility Model Content

[0004] The purpose of this invention is to address the problems in existing technologies where the main fixation method for covered stents is barbed riveting, which can easily cause vascular damage if the distance is misjudged or if plaque is present in the blood vessel. Furthermore, the outer covering is connected to the bare stent and branch stent by sintering or suturing, which can easily lead to leakage within the constructed blood cavity. Due to performance issues, the covering is also prone to breakage, resulting in reduced strength and poor continuity. Additionally, the membranes used on existing stents are mostly ePTFE porous membranes with smooth surfaces, which cannot be skinned quickly. Moreover, ePTFE membranes have stress relaxation characteristics; if micro-cracks are caused during production, they can easily expand and tear, impacting the lesion site and failing to reconstruct the blood cavity. Therefore, this invention proposes a covered stent for the treatment of aortic aneurysms.

[0005] To achieve the above objectives, this utility model adopts the following technical solution: a covered stent for treating aortic aneurysm disease, comprising a self-expanding stent, wherein a clamping member is fixedly connected to the waistline position of the expansion portion of the self-expanding stent, the clamping member being made of a superelastic shape memory alloy; the self-expanding stent comprises a bare stent and a polymer multilayer membrane; the bare stent is produced by laser cutting of a nickel-titanium tube followed by shaping, sandblasting, and polishing; the polymer multilayer membrane is coated on the inner and outer surfaces of the bare stent, the polymer multilayer membrane on the inner surface being a porous membrane, and the polymer multilayer membrane on the outer surface being a non-porous membrane; the angle between the clamping member and the self-expanding stent is less than 90°; the polymer multilayer membrane is medical-grade polyurethane; wherein the porous membrane can be prepared by phase separation method, electrospinning method, inorganic salt pore-forming method, biaxial stretching method, or spinning and weaving method. The porous membrane has a tensile strength of 1-20 MPa, preferably 5-20 MPa, and most preferably 10-20 MPa; a thickness of 1-100 micrometers, preferably 10-80 micrometers when used as a scaffold coating; a pore size of 0.1-100 micrometers, preferably 10-80 micrometers when used as a scaffold coating, and most preferably 20-60 micrometers; a porosity of 10%-90%, preferably 30%-80% when used as a scaffold coating, and most preferably 40%-90%; and a coefficient of friction of 0.07-1.0, preferably 0.07-0.8, and most preferably 0.07-0.5. When the inner porous membrane is prepared by hot-press coating, the temperature is 80-180 degrees Celsius, preferably 100-150 degrees Celsius, and most preferably 120-150 degrees Celsius. The inner porous membrane is distinguished from the inner coating material by adjusting the porosity.

[0006] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0007] In this invention, a combination of radial force anchoring and structural anchoring is used, with the self-expanding stent and clamping components. The anchoring component is replaced with a clamping component instead of the traditional barbs. After the stent reaches the designed position, it moves downward, and the anchoring component unfolds to fix it to the small blood vessels on both sides. At the same time, the upper end of the clamping component self-expands to provide double anchoring and prevent the stent from shifting. The self-expanding stent is supported and the elastic clamping component is fixed to the original blood vessel by locking it in place, avoiding additional damage. At the same time, a double-layer polyurethane membrane is used to cover the stent, which improves the anti-leakage ability while ensuring flexibility, thus avoiding damage to the blood vessel and providing stable support. Attached Figure Description

[0008] Figure 1 This invention presents a three-dimensional structural diagram of a covered stent that can be used to treat aortic aneurysm disease.

[0009] Illustration: 1. Self-expanding bracket; 2. Clamping component. Detailed Implementation

[0010] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0011] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0012] Example: Figure 1 As shown, this utility model provides a covered stent for treating aortic aneurysm disease, including a self-expanding stent 1. A clamping member 2 is fixedly connected to the waistline of the expanded portion of the self-expanding stent 1. The clamping member 2 is made of a superelastic shape memory alloy. The self-expanding stent 1 includes a bare stent and a polymer multilayer membrane. The bare stent is produced by laser cutting a nickel-titanium tube, followed by shaping, sandblasting, and polishing. The polymer multilayer membrane covers the inner and outer surfaces of the bare stent. The polymer multilayer membrane on the inner surface is a porous membrane, and the polymer multilayer membrane on the outer surface is a non-porous membrane. The angle between the clamping member 2 and the self-expanding stent 1 is less than 90°. The polymer multilayer membrane is medical-grade polyurethane. The raw materials are selected from one or more of polycaprolactone (PCL), polylactic acid (PLA), polydioxanone (PDO), polyhydroxyaliphatic ester (PHA), and polyhydroxybutyrate (PHB). The dissolving reagents are selected from N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and tetrahydrofuran (THF). The porous membrane is prepared using one or more mixed solvents selected from dimethyl sulfoxide (DMSO), wherein the porous membrane can be prepared by phase separation, electrospinning, inorganic salt pore induction, biaxial stretching, or spinning and weaving. Specifically, the tensile strength of the porous membrane is 1-20 MPa, preferably 5-20 MPa, and most preferably 10-20 MPa; the thickness is 1-100 micrometers, preferably 10-80 micrometers when used as a scaffold coating; and the pore size is 0.1-100 micrometers, preferably 10-80 micrometers when used as a scaffold coating. The optimal porosity is 20-60 micrometers; the porosity is 10%-90%, and for scaffold coating, it is more preferably 30%-80%, and optimally 40%-90%; the coefficient of friction is 0.07-1.0, more preferably 0.07-0.8, and optimally 0.07-0.5. When the inner porous membrane is prepared by hot pressing coating, the temperature is 80-180 degrees, more preferably 100-150 degrees, and optimally 120-150 degrees. The inner porous membrane distinguishes the inner and outer coating materials by adjusting the porosity.

[0013] When preparing polymer porous membranes using the phase separation method, the specific method is as follows: Polyurethane is dissolved in a solvent to prepare a 10%–20% (m / v) thermoplastic polyurethane casting solution. After filtration and degassing, an appropriate amount of the casting solution is cast onto a polytetrafluoroethylene plate. A film of the required thickness is scraped with a doctor blade and immersed in a gradient temperature ethanol coagulation bath for 10–30 min. Then, the solution is immersed in deionized water for 1 h. After that, it is placed in a vacuum oven at 40–60 °C and dried for 8–12 h to obtain a thermoplastic polyurethane porous membrane.

[0014] The specific method for preparing polymer porous membranes using electrospinning is as follows: Polyurethane is dissolved in a solvent to prepare a 1%–10% (m / v) thermoplastic polyurethane spinning solution. After filtration and degassing, the spinning solution is filled into the glass syringe of the electrospinning machine. The syringe outlet speed is adjusted to 0.01 ml / s–0.5 ml / s, the needle tip is 15–25 cm from the mandrel collector, the mandrel rotation speed is 30–70 rpm, and the voltage difference is set to 15–30 kV. The spinning time is determined according to the desired membrane thickness. The membrane is then dried in a vacuum oven at 60–80℃ for 8–12 hours to obtain the thermoplastic polyurethane porous membrane.

[0015] The specific settings and functions of this embodiment are described in detail below. Through the setting of the self-expanding stent 1 and the clamping member 2, a combination of radial force anchoring and structural anchoring is adopted. The anchoring member is changed from the traditional barbs to the clamping member 2. After the stent is moved downwards to the design position, the anchoring member unfolds and is fixed to the small blood vessels on both sides. At the same time, the upper end of the clamping member self-expands and unfolds to perform double anchoring and prevent the stent from shifting. The self-expanding stent is supported and the elastic clamping member is fixed to the original blood vessel by locking it, so as to avoid additional damage. At the same time, a double-layer polyurethane membrane is used to cover the stent, which improves the anti-leakage ability while ensuring flexibility, which can avoid damage to blood vessels and provide stable support.

[0016] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A covered stent for treating aortic aneurysm disease, characterized in that: The device includes a self-expanding support (1), and a clamping member (2) is fixedly connected to the waistline position of the expansion part of the self-expanding support (1). The self-expanding support (1) includes a bare support and a polymer multilayer film. The polymer multilayer film covers the inner and outer surfaces of the bare support. The polymer multilayer film on the inner surface is a porous film, and the polymer multilayer film on the outer surface is a non-porous film. The angle between the clamping member (2) and the self-expanding support (1) is less than 90°.

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