Improved covered stent for central vein

Abstract

The invention belongs to the technical field of medical instruments, and discloses an improved covered stent for central veins, which comprises an ePTFE (expanded polytetrafluoroethylene) covering film, a bare area, a self-expanding electrolytic-polished nitinol alloy stent and an annular radiopaque gold marking belt. The invention provides an improved covered stent for central veins, which is characterized in that the improved covered stent is made of a novel biocompatible material, the surface of the improved covered stent is covered with an improved biocompatible covering film, and the improved covered stent is designed to adapt to an anatomical structure of the central veins. The stent is intended to improve its stability, biocompatibility and reliability of long term use, and can integrate sensors or other electronic components to provide more information about the patient's health condition.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, and in particular relates to an improved composite stent for central venous use. Background Technology

[0002] With the increasing number of hemodialysis patients and the prolonged duration of their dialysis stay, the incidence of central venous disease is also increasing year by year, seriously affecting the survival rate and quality of life of dialysis patients. Central venous disease in hemodialysis patients is mainly characterized by stenosis and thrombosis, with complex causes, primarily due to hemodynamic changes, venous wall damage, or a hypercoagulable state. This can lead to tissue congestion, impaired blood return, and consequently, serious complications such as swollen hand and superior vena cava syndrome, endangering the patient's life.

[0003] As a treatment method, stent implantation can effectively restore venous patency, alleviate symptoms such as tissue congestion and edema, and improve patients' quality of life in cases of central venous stenosis or occlusion. Unlike central venous lesions caused by tumors, infections, radiation, or other reasons, central venous lesions in hemodialysis patients are often progressive, widespread (involving multiple vascular branches), and refractory (with high rates of in-stent stenosis and thrombosis). Currently, there are no commercially available venous stents specifically designed for central venous lesions in hemodialysis patients. Bare-metal stents and peritoneal stents are currently the most commonly used in clinical practice. Bare-metal stents can fit well into the vascular lumen and provide good support, but their flexibility is poor, making them less effective for long, angled vascular lesions. Furthermore, residual thrombi can protrude from the mesh gaps into the vascular lumen, leading to thrombosis recurrence or in-stent re-thrombosis. While peritoneal stents have better flexibility, their overall support is weaker, which can lead to stent collapse. Additionally, due to their peritoneal structure, they often obstruct other branch vessels during clinical procedures, causing iatrogenic secondary reflux obstruction.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing products.

[0005] Based on the above analysis, the problems and shortcomings of the existing technology are as follows:

[0006] Existing stent systems cannot simultaneously provide support, flexibility, and fit, nor can they meet the requirements for preventing thrombosis recurrence and avoiding branch blockage. Summary of the Invention

[0007] To address the problems existing in the prior art, the present invention provides an improved composite stent for central venous use.

[0008] This invention is achieved as follows: a modified central venous covered stent comprises:

[0009] Expanded polytetrafluoroethylene (ePTFE) coating, bare area, self-expanding electropolished nickel-titanium alloy support, and annular nontransparent gold marking strip;

[0010] The self-expanding electropolished nickel-titanium alloy scaffold supports a low-permeability expanded polytetrafluoroethylene (ePTFE) membrane.

[0011] Furthermore, the self-expanding electropolished nickel-titanium alloy support is divided into three functional areas: a middle coated area and bare areas at both ends.

[0012] Furthermore, at the junction of the bare area and the coated area at both ends, an annular non-transparent gold marking band divides the coated area and the bare area respectively.

[0013] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0014] First, this invention provides an improved central venous covered stent, characterized by being made of a novel biocompatible material, covered with a modified biocompatible membrane, and designed to adapt to the anatomy of the central vein. This stent aims to improve its stability, biocompatibility, and long-term reliability, and can integrate sensors or other electronic components to provide more information about the patient's health status.

[0015] The purpose of this invention is to provide an improved central venous covered stent to enhance its stability, biocompatibility, and long-term reliability. This invention primarily relates to the field of medical devices, specifically to an improved central venous covered stent. This stent is designed to address problems existing in the prior art, aiming to improve the treatment outcomes of central venous diseases and the quality of life for patients. Central venous diseases include, but are not limited to, venous thrombosis, venous stenosis, or occlusion, which can lead to serious complications such as pulmonary embolism and deep vein thrombosis.

[0016] Venous stents are mainly divided into two categories: covered stents and bare-metal stents. Covered stents achieve the purpose of supporting the blood vessel by coating a soft artificial vascular material onto the surface of a metal stent, thus isolating the blood vessel from the blood. This type of design is mainly used in the treatment of venous diseases, such as varicose veins or deep vein thrombosis. Bare-metal stents are made of metal and mainly provide physical support, dilating narrowed veins and improving blood circulation. The improved covered stent of this invention uses novel materials and an improved design of edge-migrating bare-metal support, which enhances the stent's biocompatibility, durability, and support strength. The membrane layer on the stent surface can effectively prevent thrombosis and reduce damage to the blood vessel wall, reducing the risk of infection and inflammation. At the same time, the stent's structural design fully considers the characteristics of human anatomy, ensuring greater stability during implantation and reducing the possibility of displacement.

[0017] In specific embodiments, the covered stent of the present invention can be made of a shape memory alloy material, which has good elasticity and shape memory function, and can automatically unfold to a predetermined shape under the action of body temperature, ensuring the correct position and shape of the stent in the blood vessel. At the same time, the surface coating of the stent can be made of a material with anticoagulant properties, further reducing the risk of thrombosis.

[0018] Furthermore, the present invention may also include a complementary implantation tool designed to simplify the stent implantation process, reduce surgical time, and minimize trauma to the patient. The implantation tool may include a pusher for advancing the stent to the target location, and a positioning device for ensuring precise positioning of the stent before release.

[0019] In summary, the improved covered stent for central venous use provided by this invention, through its unique design and material selection, offers a safer and more effective method for treating central venous diseases. It not only improves the success rate of treatment but also reduces postoperative complications, thereby improving the overall treatment experience for patients.

[0020] 1. The improved stent features a bare metal support at its edge, which increases stent strength and provides better support for severely calcified and occluded blood vessels, thereby restoring a larger space for blood flow.

[0021] 2. For multivessel disease, the exposed portion of the modified stent edge can avoid or reduce obstruction of branch vessels, thus preserving as many branches and reflux vessels as possible while addressing the original lesion, thereby reducing late-stage complications.

[0022] 3. The covered stent portion in the middle of the stent can reduce thrombus formation and intimal hyperplasia. At the same time, the covered stent retains better flexibility and can better fit some angled vascular lesions to achieve better surgical results.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] Enhanced stability: The optimized design ensures the stability of the stent in the central vein.

[0025] Better biocompatibility: The use of new materials has improved the biocompatibility of the scaffold.

[0026] Longer lifespan: Improved coating and material selection make the stent more suitable for long-term use.

[0027] 1. This improved stent features a bare metal support design at the edges, a unique structure that significantly enhances the overall strength of the stent. Especially when dealing with severely calcified or occluded blood vessels, the improved stent provides stronger support, helping to restore wider blood flow channels within the vessel and ensuring smooth blood flow.

[0028] 2. For cases involving multiple vessel lesions, the modified stent features an exposed metal portion at the edge, effectively preventing obstruction of branch vessels. This design addresses the original vascular lesions while preserving the patency of as many branch and reflux vessels as possible, thereby reducing potential postoperative complications and improving the success rate and safety of the procedure.

[0029] 3. The mid-segment of the modified stent utilizes a covered stent design, which effectively reduces thrombus formation and intimal hyperplasia. The covered stent retains better flexibility, allowing it to better conform to angulated vascular lesions, thus achieving a more ideal surgical outcome, improving the success rate of the procedure, and enhancing the patient's postoperative recovery.

[0030] 4. The designers carefully considered and optimized the material selection and surface treatment technology for the improved stent. By selecting materials with excellent biocompatibility and employing advanced surface treatment techniques, the improved stent can significantly reduce the risk of postoperative allergic and inflammatory reactions in patients. This design not only helps to accelerate postoperative recovery but also ensures long-term stability of the stent in the body, thereby improving overall treatment outcomes and patients' quality of life.

[0031] Secondly, as supplementary evidence of the inventive step of the claims of this invention, it is also reflected in the following important aspects:

[0032] (1) The expected benefits and commercial value of the technical solution of this invention after transformation are as follows:

[0033] The number of hemodialysis patients is increasing year by year. As of the end of December 2022, there were 844,265 hemodialysis patients, an increase of 156,645 from the previous year. The incidence of central venous disease in hemodialysis patients is also increasing annually, seriously affecting the quality of dialysis and their survival. The application of venous stents can improve vascular access in hemodialysis patients and increase their life expectancy. This invention's stent is designed specifically for the characteristics of central venous disease in hemodialysis patients. Considering the multi-branched nature of central veins and the inherent stubbornness and recurrence of central venous disease in hemodialysis patients, the technical solution combines the advantages of both bare-metal stents and covered stents, enabling it to better meet the treatment needs of the disease. It reduces in-stent re-thrombosis while avoiding blockage of branch vessels, achieving better treatment results. Therefore, it has broad application prospects in clinical practice.

[0034] (2) The technical solution of this invention fills a technical gap in the industry both domestically and internationally:

[0035] Currently available venous stent systems are either bare-metal stents or covered stents. Existing research data suggests that these two types of stents each have their advantages and disadvantages in terms of vascular stress and radial force: ① Bare-metal stents offer better flexibility and are the best in terms of stent stress and strain, but are worse in terms of vascular stress or strain; ② Peritoneal stents offer the best radial force, but are less effective in terms of stress or strain on the stent itself. This invention combines the characteristics of both types of stents, balancing flexibility, support, and compliance. It allows for appropriate stent placement based on the location and characteristics of the vascular lesion, addressing complex vascular conditions.

[0036] (3) Whether the technical solution of the present invention overcomes technical bias:

[0037] To address some central venous occlusion lesions, and considering the coaxiality principle of stent placement, long stents are often required. While covered stents offer advantages in reducing in-stent rethrombosis, long covered stents can obstruct major branch vessels. Therefore, in clinical practice, physicians often choose to place both covered and bare-metal stents simultaneously to meet the treatment needs. This design fully considers practical clinical needs and the characteristics of central venous lesions in hemodialysis patients, integrating two types of stents into one system. This breaks through the single structure of traditional stent systems, allowing for wider application. Attached Figure Description

[0038] Figure 1 This is a structural block diagram of an improved central venous covered stent provided in an embodiment of the present invention.

[0039] Figure 2 This is a schematic diagram of a stent placed for left brachiocephalic vein occlusion provided in an embodiment of the present invention.

[0040] Figure 1In the middle: 1. Expanded polytetrafluoroethylene (ePTFE) coating; 2. Bare area; 3. Self-expanding electropolished nickel-titanium alloy support; 4. Annular radiopaque gold marking band. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0042] like Figure 1 As shown, an embodiment of the present invention provides a modified central venous covered stent comprising:

[0043] 1. Expanded polytetrafluoroethylene (ePTFE) coating; 2. Bare area; 3. Self-expanding electropolished nickel-titanium alloy support; 4. Annular non-transparent gold marking band.

[0044] The self-expanding electropolished nickel-titanium alloy scaffold 3 supports a low-permeability expanded polytetrafluoroethylene (ePTFE) membrane 1.

[0045] The self-expanding electropolished nickel-titanium alloy support 3 provided in this embodiment of the invention is divided into three functional areas: a middle coated area and two bare areas 2 at both ends.

[0046] In this embodiment of the invention, the boundary between the two bare areas 2 and the coated area is divided into the coated area and the bare area 2 by an annular non-transparent gold marking band 4.

[0047] The improved central venous covered stent of the present invention is improved and optimized through the following principles:

[0048] 1. Selection of support materials and structure

[0049] This invention uses expanded polytetrafluoroethylene (ePTFE) as the scaffold coating material. This material has low permeability, which can effectively prevent fluid penetration, thereby reducing the risk of fluid leakage in the central vein. The ePTFE membrane is supported by a self-expanding, electropolished nitinol alloy stent 3. Nitinol alloy has excellent biocompatibility and self-expanding properties, and can automatically expand to adapt to the inner wall of the vein during implantation, stabilizing the stent's positioning while reducing pressure on surrounding tissues.

[0050] 2. Optimization of self-expanding design

[0051] Nickel-titanium alloy stents undergo electropolishing to reduce surface roughness and blood adhesion, effectively preventing thrombosis. Simultaneously, their self-expanding design ensures reliable stent support within the vein, automatically adapting to changes in vascular morphology. This characteristic allows the stent to remain stably in place even in cases of vascular stenosis or dilation, thereby reducing the risk of stent displacement and increasing implantation stability and safety.

[0052] 3. Functional area zoning design

[0053] The stent design consists of a central covered area and bare areas at both ends, allowing the stent to provide support while maintaining partially exposed areas at both ends, reducing the impact on blood flow. The bare areas at both ends allow blood to flow freely, enhancing stent support while avoiding obstruction of other reflux vessels, reducing complications, and improving the safety of stent placement.

[0054] 4. Application of gold band markings

[0055] A ring-shaped, radiopaque gold marker band 4 is placed at the boundary between the covered and bare areas. This band allows for clear visualization of the stent's precise location via X-ray, aiding in determining stent deployment and positioning during imaging examinations. The marker band ensures clear identification of the stent's position and status during postoperative follow-up, facilitating subsequent observation and maintenance by physicians, thereby improving stent safety and monitoring accuracy.

[0056] Through the above-mentioned improved design, the present invention has achieved good results in improving the biocompatibility, antithrombotic performance and visibility of the stent.

[0057] The purpose of this invention is to provide an improved central venous covered stent to enhance its stability, biocompatibility, and long-term reliability. This invention primarily relates to the field of medical devices, and specifically to an improved central venous covered stent. This stent is designed to address problems existing in the prior art, aiming to improve the treatment outcomes of central venous diseases and enhance patients' quality of life.

[0058] Venous stents are mainly divided into two categories: covered stents and bare-metal stents. Covered stents achieve the purpose of supporting the blood vessel by coating a soft artificial vascular material onto the surface of a metal stent, thus isolating the blood vessel from the blood. This type of design is mainly used in the treatment of severe stenosis or occlusion of central veins in hemodialysis patients. Bare-metal stents, on the other hand, are made of metal and mainly provide physical support, dilating narrowed veins and improving blood circulation. The improved covered stent of this invention uses novel materials and an improved design of edge-migrating bare-metal support, which enhances the stent's biocompatibility, durability, and support strength. The membrane layer on the stent surface can effectively prevent thrombosis and reduce damage to the blood vessel wall, lowering the risk of infection and inflammation. At the same time, the stent's structural design fully considers the characteristics of human anatomy, ensuring greater stability during implantation and reducing the possibility of displacement.

[0059] In specific embodiments, the covered stent of the present invention can be made of a shape memory alloy material, which has good elasticity and shape memory function, and can automatically unfold to a predetermined shape under the action of body temperature, ensuring the correct position and shape of the stent in the blood vessel. At the same time, the surface coating of the stent can be made of a material with anticoagulant properties, further reducing the risk of thrombosis.

[0060] Furthermore, the present invention may also include a complementary implantation tool designed to simplify the stent implantation process, reduce surgical time, and minimize trauma to the patient. The implantation tool may include a pusher for advancing the stent to the target location, and a positioning device for ensuring precise positioning of the stent before release.

[0061] In summary, the improved covered stent for central venous use provided by this invention, through its unique design and material selection, offers a safer and more effective method for treating central venous diseases. It not only improves the success rate of treatment but also reduces postoperative complications, thereby improving the overall treatment experience for patients.

[0062] To achieve the above objectives, the present invention provides the following technical solution:

[0063] Structure: The scaffold is made of a novel biocompatible material that has better flexibility and strength.

[0064] Covering: The stent surface is covered with a modified biocompatible covering, which has better antithrombotic properties.

[0065] Design: The stent design has been optimized to better adapt to the anatomy of the central vein, ensuring its stability and safety. Due to the complexity and diversity of central venous lesions, often involving calcification, multiple vessels, and angled lesions, existing stent types cannot effectively address clinical issues. The design advantages are as follows: 1. The modified stent features a bare metal edge support, increasing stent strength and providing better support for severely calcified and occluded vessels, thus restoring a larger blood flow diameter.

[0066] 2. For multivessel disease, the exposed portion of the modified stent edge can avoid or reduce obstruction of branch vessels, thus preserving as many branches and reflux vessels as possible while addressing the original lesion, thereby reducing late-stage complications.

[0067] 3. The covered stent portion in the middle of the stent can reduce thrombus formation and intimal hyperplasia. At the same time, the covered stent retains better flexibility and can better fit some angled vascular lesions to achieve better surgical results.

[0068] 4. Advantages

[0069] Compared with the prior art, the present invention has the following advantages:

[0070] Enhanced stability: The optimized design ensures the stability of the stent in the central vein.

[0071] Better biocompatibility: The use of new materials has improved the biocompatibility of the scaffold.

[0072] Longer lifespan: Improved coating and material selection make the stent more suitable for long-term use.

[0073] Such supports can be manufactured using various methods, such as 3D printing and metal processing.

[0074] 5. Conclusion

[0075] This improved central venous covered stent system provides patients with a safer and more effective treatment option and has broad application prospects.

[0076] 6. Design Figure 2 (Improved design of edge-shifted bare metal support: retains metal support structure at both ends (1cm each) without coating)

[0077] Improvements were made to the existing covered stent: the existing covered stent is fully covered, while the improved stent is only covered in the middle part, with the two ends (about 1cm each) not covered. The bare metal stent at the edge and the covered stent are integrated as one piece, not spliced ​​together.

[0078] The coated stent comprises a self-expanding, electropolished nickel-titanium alloy stent supporting a low-permeability expanded polytetrafluoroethylene (ePTFE) membrane. The stent is divided into three functional zones: a central coated zone and two bare zone ends. The boundaries between the bare zone ends and the coated zone are each defined by a ring-shaped radiopaque gold marker.

[0079] like Figure 2 As shown, taking the placement of a stent in the left brachiocephalic vein occlusion as an example, the solid blue line represents the covered stent area, and the dashed red line represents the bare stent area. The bare stent area will not affect the return of other major veins, while providing better stent support.

[0080] The design advantages are as follows:

[0081] 1. This improved stent features a bare metal support design at the edges, a unique structure that significantly enhances the overall strength of the stent. Especially when dealing with severely calcified or occluded blood vessels, the improved stent provides stronger support, helping to restore wider blood flow channels within the vessel and ensuring smooth blood flow.

[0082] 2. For cases involving multiple vessel lesions, the modified stent features an exposed metal portion at the edge, effectively preventing obstruction of branch vessels. This design addresses the original vascular lesions while preserving the patency of as many branch and reflux vessels as possible, thereby reducing potential postoperative complications and improving the success rate and safety of the procedure.

[0083] 3. The mid-segment of the modified stent utilizes a covered stent design, which effectively reduces thrombus formation and intimal hyperplasia. The covered stent retains better flexibility, allowing it to better conform to angulated vascular lesions, thus achieving a more ideal surgical outcome, improving the success rate of the procedure, and enhancing the patient's postoperative recovery.

[0084] 4. The designers carefully considered and optimized the material selection and surface treatment technology for the improved stent. By selecting materials with excellent biocompatibility and employing advanced surface treatment techniques, the improved stent can significantly reduce the risk of postoperative allergic and inflammatory reactions in patients. This design not only helps to accelerate postoperative recovery but also ensures long-term stability of the stent in the body, thereby improving overall treatment outcomes and patients' quality of life.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An improved central venous stent graft, characterized in that: It includes an expanded polytetrafluoroethylene coating, a bare area, a self-expanding electrolytically polished nitinol alloy stent and an annular radiopaque gold marker band; the self-expanding electrolytically polished nitinol alloy stent supports a low-permeability expanded polytetrafluoroethylene coating, wherein the stent is divided into a middle coating area and bare areas at both ends.

2. The improved stent graft according to claim 1, characterized in that: The self-expanding electrolytically polished Nitinol alloy stent has good self-expanding performance. After implantation, the stent automatically expands to adapt to the inner wall of the vein, ensuring that the stent remains stably in place.

3. The improved stent graft according to claim 1, characterized in that: The expanded polytetrafluoroethylene (ePTFE) coating is a low-permeability membrane.

4. The improved stent graft according to claim 1, characterized in that: An annular radiopaque gold marking band is provided at the junction of the bare areas at both ends and the middle coated area.

5. The improved stent graft according to claim 1, characterized in that: The surface of the self-expanding electrolytically polished Nitinol alloy stent is treated with electrolytic polishing.

Images