Controllable self-expanding covered stent
By designing a controllable self-expanding covered stent and utilizing a stent framework with rhomboid open-loop units and wave-shaped rod structures, the problems of poor apposition and damage of covered stents within curved cerebral blood vessels were solved, achieving highly efficient treatment results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 李明华
- Filing Date
- 2023-11-30
- Publication Date
- 2026-05-15
AI Technical Summary
Existing covered stents are difficult to adhere effectively to the walls of curved cerebral blood vessels, posing a risk of endoleak, and bulb-type stents may damage blood vessels, resulting in poor treatment outcomes.
A controllable self-expanding covered stent is designed, which adopts a stent skeleton with a rhomboid open-loop unit and a wave-shaped bar structure, combined with nickel-titanium alloy material, which has sufficient flexibility and support. The covered part can self-expand and expand through the curved blood vessel, and the proximal end is connected to the push tube for easy position adjustment.
It achieves good adhesion within tortuous blood vessels, reduces the risk of endoleak, avoids vascular damage, provides highly controllable treatment procedures, and improves treatment success rates.
Smart Images
Figure CN224235602U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of vascular stent technology, and in particular to a controllable self-expanding covered stent. Background Technology
[0002] Small vessel wall rupture (defect) refers to damage to the walls of cerebral blood vessels (characterized by their small diameter and tortuous course). This includes cerebral aneurysms (saccular aneurysms, pseudoaneurysms, traumatic aneurysms, dissecting aneurysms, fusiform aneurysms, etc.), carotid-cavernous fistulas (CCF), and other arterial wall ruptures caused by various reasons. Cerebral aneurysms are a common disease, with an incidence rate of 5-7% in the general population, mostly affecting middle-aged and elderly people, and predominantly women. The annual incidence of cerebral aneurysm rupture is 0-1%, and once ruptured, the direct mortality rate exceeds 20%. Other vessel wall ruptures (including CCF) are mostly caused by direct trauma or secondary to other lesions invading the blood vessels. Mild cases may present with eye congestion, bulging eyes, and vision loss, while severe cases can lead to massive hemorrhage and death. Currently, treatment for cerebral aneurysms includes traditional surgical exposure and clipping surgery and endovascular treatment techniques. Due to the significant trauma and high complication rate of surgical exposure and clipping surgery, endovascular treatment is now the primary approach for treating cerebral aneurysms in the medical field. Endovascular treatment techniques include endovascular coil embolization of aneurysms, endovascular stent grafting, aneurysm orifice bleedering devices, and intra-aneurysm bleedering devices.
[0003] Endovascular coil embolization of cerebral aneurysms has been used clinically for over 20 years, but it remains the primary technique for endovascular treatment of cerebral aneurysms. In recent years, the use of flow-disrupting devices for treating cerebral aneurysms has gained increasing clinical acceptance, with more and more large-scale clinical case reports. Therefore, current research on flow-disrupting devices for treating cerebral aneurysms (including orifice flow-disrupting devices and intravascular flow-disrupting devices) is quite active. Covered stent technology has limited clinical application, used only in a few complex cerebrovascular diseases. The mechanism of endovascular coil embolization of cerebral aneurysms is to fill the aneurysm cavity with coils to prevent or eliminate aneurysm rupture. The ultimate goal is complete and dense occlusion, but the success rate is only about 70%, despite the use of various auxiliary embolization techniques. In addition, the coil embolization technique for cerebral aneurysms carries risks such as intraoperative aneurysm rupture related to microcatheters, microguidewires, and coils, as well as the adverse consequences of the aneurysm's mass effect compressing surrounding brain tissue after coil embolization. Intra-aneurysm flow disruptors involve inserting a specially structured material into the aneurysm cavity to alter blood flow, leading to thrombus formation and eventual occlusion. This technique is suitable for aneurysms at cerebral vascular bifurcation sites that are difficult to treat with other methods. Its disadvantages include the individualized nature of the aneurysm, high material requirements, the possibility of thrombus escape, and the risk of intraoperative rupture within the aneurysm cavity, making it unsuitable for treating ruptured cerebral aneurysms. Orifice flow disruptors involve inserting a fine-mesh stent into the carrier artery at the aneurysm orifice to reduce and alter the blood flow into the aneurysm cavity, gradually forming a thrombus to occlude the aneurysm. Its disadvantages include the inability to immediately occlude the aneurysm, making it unsuitable for ruptured cerebral aneurysms, and the inability to completely occlude the aneurysm cavity in some aneurysms, requiring a high level of surgical skill.
[0004] In addition, there are covered stents that can immediately repair vascular wall defects. However, existing covered stents are balloon-expandable, which has poor controllability, makes it difficult to navigate within tortuous cerebral blood vessels, and poor apposition after deployment can easily cause endoleaks, failing to achieve the therapeutic effect. Moreover, the expanding balloon can easily damage blood vessels, causing intracranial hemorrhage, leading to serious complications or even death. For example, the only existing covered stent for cerebrovascular disease, the Willis, involves balloon expansion and release. The balloon pressure is high during expansion, and the stent is relatively rigid and straight, making it easy to damage blood vessels within tortuous cerebral vessels. Its poor flexibility also makes it difficult to cross tortuous blood vessels, and poor apposition within tortuous vessels can easily cause endoleaks, affecting the therapeutic effect. Therefore, it is necessary to improve existing cerebral vascular covered stents to provide a covered stent with sufficient support and good flexibility, which can avoid damage to tortuous segments of blood vessels and can maximize the immediate repair of defects in the walls of tortuous blood vessels (cerebral blood vessels). Utility Model Content
[0005] Therefore, based on the above background, this utility model provides a controllable self-expanding covered stent. The covered part has a rhomboid open-loop unit and its waveform, which makes it have sufficient tension on the circumference. Covering a thin covered part of a reasonable size can not only maintain its support in the tortuous segment of the blood vessel, but also have sufficient flexibility to avoid damage to the tortuous segment of the blood vessel. During operation, after the covered part is fully expanded, its proximal bare stent part and the distal end of the delivery tube remain connected in the delivery catheter. At this time, the stent position can be appropriately withdrawn and adjusted as needed to ensure the treatment effect.
[0006] The technical solution provided by this utility model is as follows:
[0007] A controllable self-expanding membrane-covered stent includes a stent skeleton, wherein the stent skeleton is a hollow cylindrical body;
[0008] It also includes coating;
[0009] The support frame is composed of axially arranged wave coil units, each wave coil unit including two wave rods with wave troughs and wave crests facing each other;
[0010] The support frame consists of, from top to bottom, a distal end, a covered portion, and a proximal end;
[0011] The film is wrapped around the support frame corresponding to the film portion;
[0012] The adjacent wave-shaped bars at the distal and proximal ends are connected by a transversely continuous connecting bar, and the wave-shaped bars at the distal and proximal ends and the connecting bar form a rhomboid closed grid.
[0013] The upper and lower adjacent corrugated rods of the coating section are connected by a transversely discontinuous connecting rod;
[0014] The corrugated rod closest to the coating part at the distal end is connected to the corrugated rod closest to the distal end of the coating part by a transversely discontinuous connecting rod;
[0015] The corrugated rod closest to the coating part at the proximal end is connected to the corrugated rod closest to the proximal end of the coating part by a transversely discontinuous connecting rod.
[0016] One implementation method is that the connecting rod is wavy.
[0017] One implementation method is that the connecting rod is S-shaped.
[0018] One implementation is that the distal end has a first horn opening and the proximal end has a second horn opening.
[0019] One implementation method is as follows: the distal end port and the proximal end port are respectively provided with a first metal mark and a second metal mark around their circumference to cooperate with the delivery guide wire.
[0020] One implementation method is that a third metal mark is embedded in the upper and lower ends of the coating portion around its circumference.
[0021] One implementation method is that the film is applied to the outside of the support frame corresponding to the film part by hot pressing.
[0022] One implementation is as follows: the longitudinal length of the distal end is 2-3 mm, the longitudinal length of the proximal end is 5 mm, and the longitudinal length of the covered portion is 7-25 mm.
[0023] One implementation method is as follows: the coating is made of one of the following materials: expanded tetrafluoroethylene membrane, polylactic acid polymer membrane or nano membrane, and the thickness of the coating is 15-20 μm.
[0024] One implementation method is that the wave rod is made of nickel-titanium alloy.
[0025] One implementation method is that the first metal mark, the second metal mark, and the third metal mark are all made of platinum.
[0026] One implementation method is that the support frame is made of woven metal rods or made of metal laser cutting.
[0027] The beneficial effects of adopting the above technical solution are as follows:
[0028] ①This utility model has sufficient support and flexibility, allowing it to easily pass through and be placed on curved blood vessels while avoiding damage to the curved segments of the blood vessel:
[0029] The open-loop unit and its waveform of the covered part, combined with the super-elastic properties of the nickel-titanium alloy metal rod material, can maintain sufficient tension in the axial direction. The outer diameter and length of the covered part on the stent skeleton are slightly larger than the corresponding stent skeleton to accommodate the full expansion of the covered stent segment. This allows it to adhere tightly to the intima of the tortuous blood vessel and maintain the flexibility of the tortuous segment of the blood vessel, avoiding damage to the tortuous segment of the blood vessel and ensuring the success rate of the operation and the treatment effect.
[0030] ② The stent adheres well to the vessel wall, reducing or eliminating endoleak: The stent skeleton has a funnel-shaped structure at both the proximal and distal ends, which anchors the stent in the blood vessel and makes the two ends of the lining also funnel-shaped, which enhances the adhesion of the membrane at both ends and prevents endoleak.
[0031] ③This utility model is a self-expanding stent, which can avoid the damage to cerebral blood vessels caused by the high-pressure balloon of the balloon during the expansion of the balloon of the balloon-expanding stent, especially in the tortuous section of the blood vessel.
[0032] ④ This utility model offers good controllability during release, especially after the covered stent is fully expanded. It can be appropriately retracted and adjusted until satisfactory placement is achieved, ensuring treatment effectiveness and enhancing the operator's confidence. Its design features a bare stent section of a certain length at the proximal end, which is the controllable part during stent placement. This ensures that when the covered stent is fully expanded, the bare stent at the proximal end remains connected to the distal end of the delivery tube within the delivery catheter, allowing for appropriate retraction and adjustment of the covered stent. ⑤ This utility model has platinum metal markings on the circumference of the port at the distal end of the stent, the port at the proximal end, and the proximal and distal ends of the covered part. These markings are opaque under X-ray fluoroscopy and easy to identify, which is used for accurate positioning of the covered stent during placement. Attached Figure Description
[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 This is a schematic diagram of the structure of this utility model;
[0035] Figure 2 This is a schematic diagram of the support frame of this utility model;
[0036] Figure 3 This is a schematic diagram of the structure of the film-coated support of this utility model in a hypothetical flat and unfolded state;
[0037] Figure 4 This is a schematic diagram of the structure of the support frame of this utility model in a hypothetical flat and unfolded state;
[0038] Figure 5 This is a schematic diagram of the coating structure of this utility model;
[0039] Figure 6 For reference regarding the usage state of this utility model Figure 1 ;
[0040] Figure 7 For reference regarding the usage state of this utility model Figure 2 ;
[0041] Figure 8 For reference regarding the usage state of this utility model Figure 3 . Detailed Implementation
[0042] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0043] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "vertical," "circumferential," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0044] In the description of this utility model, "first feature" and "second feature" may include one or more of the indicated features. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the indicated features.
[0045] The present invention will be further described below with reference to the accompanying drawings.
[0046] Example 1: According to Figures 1 to 8 The controllable self-expanding covered stent shown includes a stent skeleton 1, which is a hollow cylindrical body; it also includes a covering film 2; the covering film 2 is wrapped around the stent skeleton corresponding to the covering part 11.
[0047] The support frame 1 is made by directly weaving or laser cutting of corrugated rods; in specific implementations, the corrugated rods are made of nickel-titanium alloy, which has shape memory and superelasticity properties to ensure that the support frame has sufficient tension. The support frame 1 is composed of axially arranged corrugated coil units 15, each corrugated coil unit 15 including two corrugated rods with troughs and crests facing each other (see...). Figure 3 As shown); the stent skeleton 1 consists of a distal end 13 (L1), a covered portion 11 (L2), and a proximal end 12 (L3) from top to bottom; the lower proximal end is the end closest to the delivery catheter 7 when the covered stent is inserted into the blood vessel, and conversely, the distal end is the end furthest from the delivery catheter 7.
[0048] The wave-shaped rods 14 of the distal end 13 and the proximal end 12 that are adjacent vertically are connected by a transversely continuous connecting rod 16, and the wave-shaped rods 14 of the distal end 13 and the proximal end 12 and the connecting rod 16 form a rhomboid closed grid 17.
[0049] The adjacent corrugated rods 14 of the coating section 11 are connected by discontinuous transverse connecting rods 16; the corrugated rod 14 closest to the coating section 11 at the distal end 13 is connected to the corrugated rod 14 closest to the distal end 13 of the coating section 11 by discontinuous transverse connecting rods 16; that is, the connecting rods 14 of the coating section are arranged with a number of corrugated peaks or troughs spaced laterally, and the number of corrugated peaks or troughs between adjacent connecting rods is random, for example, the number of corrugated peaks or troughs can be random, such as 3, 4 or 5. The adjacent corrugated rods of the coating section and the spaced connecting rods form an open-loop grid structure, which is beneficial to the transverse support force and longitudinal flexibility of the support, thereby facilitating the full expansion of the support and increasing the wall adhesion.
[0050] The corrugated rod 14 closest to the coating part 11 at the proximal end 12 is connected to the corrugated rod 14 closest to the proximal end 12 of the coating part 11 by a transversely discontinuous connecting rod 16, which is the same as the arrangement of the connecting rods of the coating part.
[0051] The connecting rod 16 is wavy. Specifically, as shown below... Figures 1 to 4 As shown, the connecting rod can be S-shaped, but its implementation is not limited to S-shaped; for example, it can also be a wave shape composed of two or three S-shapes. The wave shape of the connecting rod can also play a certain role in buffering and deformation, so as to further increase the full expansion of the support and increase the wall adhesion.
[0052] The distal end 13 has a first flared opening 131, and the proximal end 12 has a second flared opening 121. This not only anchors the stent within the blood vessel but also makes both ends of the covering flared, especially at the proximal end, to increase apposition to the vessel wall and prevent endoleak.
[0053] The proximal end 12 has a first metal mark 3 around its port circumference that mates with the guide wire, and the distal end 13 has a second metal mark 4 around its port circumference. The upper and lower ends of the coating portion 11 are respectively circumferentially embedded with third metal marks 5. The first metal mark 3, the second metal mark 4, and the third metal mark 5 are all made of platinum. In specific applications, such as... Figure 7As shown, the first metal mark 3 matches the delivery guidewire 6. It engages with the delivery guidewire 6 inside the delivery conduit 7 to ensure that the unexpanded stent skeleton is connected to the distal end of the delivery guidewire before it exits the delivery conduit, allowing for free pushing and retraction. It can also serve as an X-ray opaque mark for easy identification during operation, enabling accurate positioning of the covered stent during placement.
[0054] In specific implementation, the number of the first metal mark 3, the second metal mark 4, and the third metal mark 5 can be 3-4, all of which are arranged equidistantly along the circumference of the support frame.
[0055] The coating 2 is applied to the outside of the support frame corresponding to the coating portion by hot pressing. For example... Figure 5 As shown, the coating 2 can be fixed to the support frame via circumferentially distributed hot-pressing points 21. In specific implementation, the area of the fixing points is approximately 1 mm². 2 Size, and the number of fixed points is no less than 3.
[0056] In specific implementation, the coating can be made of one of expanded polytetrafluoroethylene film, polylactic acid polymer film or nanofilm. The film thickness is ultra-thin, 15-20um, and its length and tubular diameter are slightly larger than the length and tubular diameter of the same specification of the support skeleton. It is hot-pressed and wrapped on the support skeleton.
[0057] Specifically, it can be as follows:
[0058] Except for the heat-pressing points, the covering is in a free state to accommodate the flexibility of the stent skeleton. Given the funnel-shaped design of the distal and proximal ends of the stent skeleton, the diameter and length of the tubular covering must be larger than the corresponding stent skeleton portion to maximize the stent's flexibility and apposition within the blood vessel. In practice, the diameter and length of the covering tube are approximately 10% larger than the maximum diameter and length of the stent skeleton, respectively.
[0059] In specific implementation, the longitudinal length L1 of the distal end 13 is 2-3 mm, the longitudinal length L2 of the proximal end 12 is 5 mm, and the longitudinal length L3 of the covered portion 11 is 7-25 mm. That is, the proximal end of the stent skeleton is a bare stent segment of a certain length, which can remain connected to the distal end of the delivery guidewire 6 within the delivery catheter 7 even after the covered stent segment is fully expanded. Before judging whether the treatment effect of the covered stent is satisfactory, the position of the stent can be withdrawn and adjusted until satisfactory.
[0060] In practice, the length of the stent skeleton corresponding to the covered portion can be divided into 6 levels, with each level having a length of 7, 10, 13, 16, 20, and 25 mm. The diameter of the stent skeleton corresponding to the covered portion is 3.0-5.5 mm, with a level difference of 0.25 mm during grading. Specifically, the diameter of each level is 3.0, 3.25, 3.5, 3.75, 4.0, 4.25, 4.5, 4.75, 5.0, 5.25, and 5.5 mm, allowing operators to more easily select covered stents for different lesion sizes.
[0061] In specific applications, such as Figure 6 This is the state of the covered stent when it is bent. Figure 7 (in Figure 7 The structure of the connecting rod is not shown. This means that the covered part of the covered stent device is fully expanded and the controllable part (proximal end) is not released. If the treatment purpose has not been achieved at this time, the stent system can be retrieved and adjusted (as described above) before being released. Figure 8 This means that the controllable part (proximal end) has been released and the covered stent device has been completely detached. At this point, the stent system can no longer be recovered or adjusted.
[0062] This invention is a self-expanding stent, which can ensure delivery within a microcatheter, travel within tortuous blood vessels, and placement. The selection of stent skeleton material and the matching of rhomboid open-loop units with waveforms can ensure the flexibility and lateral support of the stent. The lining can ensure the occlusion effect and endothelialization. The reasonable matching of the stent skeleton and the lining can ensure the flexibility of the lining stent device within tortuous blood vessels.
[0063] This invention's controllable self-expanding covered stent can maximize the immediate repair of lesions with defects in the walls of tortuous blood vessels (cerebral blood vessels). It overcomes many shortcomings of similar devices, such as dense mesh stents, which cannot immediately cure lesions, and traditional bulb-expanded covered stents, which are not flexible enough and have difficulties in navigating tortuous blood vessels, poor wall adhesion, and vascular damage. It can greatly expand the indications and effectiveness of this device in the treatment of lesions with defects in the walls of cerebral blood vessels (except for those with functional branches in the treatment segment).
[0064] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.
Claims
1. A controllable self-expanding membrane-coated stent, comprising a stent skeleton, wherein the stent skeleton is a hollow cylindrical body; characterized in that, It also includes coating; The support frame consists of, from top to bottom, a distal end, a covered portion, and a proximal end; The film is wrapped around the support frame corresponding to the film portion; The support frame is composed of axially arranged wave coil units, each wave coil unit including two wave rods with wave troughs and wave crests facing each other; The adjacent wave-shaped bars at the distal and proximal ends are connected by a transversely continuous connecting bar, and the wave-shaped bars at the distal and proximal ends and the connecting bar form a rhomboid closed grid. The upper and lower adjacent corrugated rods of the coating section are connected by a transversely discontinuous connecting rod; The corrugated rod closest to the coating part at the distal end is connected to the corrugated rod closest to the distal end of the coating part by a transversely discontinuous connecting rod; The corrugated rod closest to the coating part at the proximal end is connected to the corrugated rod closest to the proximal end of the coating part by a transversely discontinuous connecting rod.
2. The controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The connecting rod is wavy.
3. The controllable self-expanding membrane-coated stent according to claim 2, characterized in that, The connecting rod is S-shaped.
4. The controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The distal end has a first horn opening, and the proximal end has a second horn opening.
5. The controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The distal end port and the proximal end port are respectively provided with a first metal mark and a second metal mark around their circumference to cooperate with the delivery guide wire.
6. The controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The upper and lower ends of the coated portion are respectively embedded with a third metal mark around their circumference.
7. The controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The film is applied to the outside of the support frame corresponding to the film portion by hot pressing.
8. The controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The longitudinal length of the distal end is 2-3 mm, the longitudinal length of the proximal end is 5 mm, and the longitudinal length of the covered portion is 7-25 mm.
9. A controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The coating is made of one of the following materials: expanded polytetrafluoroethylene membrane, polylactic acid polymer membrane, or nanofilm, and the thickness of the coating is 15-20 μm.
10. A controllable self-expanding membrane-coated stent according to claim 1, characterized in that, The wave rod is made of nickel-titanium alloy.