Covered stent
By employing a combination of polygonal ring design and flexible connectors in the TIPS covered stent, the problems of low stent support strength and easy deformation were solved, achieving stable blood flow control and reducing the risk of hepatic encephalopathy and portal hypertension.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2026-03-17
AI Technical Summary
Existing TIPS covered stents with controllable diameter have problems with low support strength and easy deformation, which makes it difficult to control blood flow and may cause complications such as hepatic encephalopathy or portal hypertension.
The stent employs a combination structure of a controllable diameter support and a self-expanding support. The design of the polygonal ring enhances the support strength. The polygonal structure is connected by diagonal connections or shared sides. Combined with a first connector with good flexibility, the stent maintains a stable diameter under blood impact and compression.
It significantly improves the support strength and flexibility of the stent, effectively regulates blood flow, avoids hepatic encephalopathy and portal hypertension, and ensures the stability and safety of blood flow.
Smart Images
Figure CN223995018U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of covered stent technology, and in particular to a covered stent. Background Technology
[0002] The incidence of cirrhosis is increasing globally. In cirrhotic livers, scar tissue significantly slows blood flow from the portal vein across the liver, leading to portal hypertension. This subsequently affects the gastric coronary vein, splenic vein, and mesenteric vein. As pressure gradually increases, blood flow in the gastric coronary vein also begins to reverse, flowing against the liver. Ultimately, this leads to the following in cirrhotic patients: the spleen enlarges due to persistent congestion, resulting in hypersplenism and low platelet count; the gastric coronary vein becomes increasingly thick and thin due to repeated reverse blood flow, forming varicose veins. Varicose veins are prone to rupture, leading to bleeding, which has a high mortality rate.
[0003] Transjugular intrahepatic portosystemic shunt (TIPS) is a minimally invasive interventional technique that involves puncturing the portal vein through the hepatic vein via the jugular vein to create a portosystemic shunt between the hepatic vein and the portal vein. This aims to reduce portal vein pressure and treat a range of complications associated with portal hypertension, such as esophageal and gastric variceal bleeding and refractory ascites. As an interventional procedure, TIPS is characterized by minimal trauma, rapid recovery, clear efficacy, and high repeatability. It has become one of the effective treatments for complications caused by cirrhosis, including portal hypertension.
[0004] In the prior art, TIPS covered stents use a polymer covering membrane to constrain the expansion diameter of the self-expanding stent's intermediate segment, thereby achieving the effect of regulating blood flow. However, as the implantation time increases, the polymer covering membrane is prone to deformation, making it difficult to keep the self-expanding stent's intermediate segment at a suitable set diameter. Furthermore, the self-expanding stent's intermediate segment is easily deformed by compression or blood impact, ultimately leading to difficulty in controlling the blood flow passing through it and inducing hepatic encephalopathy. Summary of the Invention
[0005] One technical problem solved by this invention is how to address the issue of low support strength and easy deformation in controllable diameter supports.
[0006] A film-coated support includes a support frame and a covering film disposed on the support frame. The support frame includes a controllable diameter support and a self-expanding support. At least one side of the controllable diameter support is connected to the self-expanding support in the axial direction. The controllable diameter support includes at least one polygonal ring. The polygonal ring includes a plurality of polygonal structures connected sequentially in the circumferential direction. The number of sides of each polygonal structure is at least four. In the same polygonal ring, adjacent polygonal structures are connected diagonally or share the same side.
[0007] One technical effect of one embodiment of this utility model is that a controllable diameter support body with at least one polygonal ring arranged axially is used as a balloon expandable stent. Since the polygonal ring includes multiple polygonal structures connected sequentially in the circumferential direction, and the polygonal structure has at least four sides, and adjacent polygonal structures are connected diagonally or share a side, at least four interior angles need to be bent and deformed simultaneously to cause deformation of the polygonal structure. Taking advantage of the difficulty of bending and deforming polygonal structures, the support strength of the controllable diameter stent is significantly improved, thereby effectively maintaining the adjusted diameter. This avoids excessive shunting caused by the expansion of the controllable diameter stent due to blood impact, which could lead to complications such as hepatic encephalopathy, or reduces the blood flow caused by the shrinking diameter of the controllable diameter stent due to compression, which could lead to portal hypertension and increased risk of bleeding. Attached Figure Description
[0008] Figure 1 This is a schematic diagram of the structure of a film-coated scaffold according to Embodiment 1;
[0009] Figure 2 This is a schematic diagram showing the location of a covered stent in the liver.
[0010] Figure 3 This is a schematic diagram of the structure of a self-expanding support.
[0011] Figure 4a , 4b 4c and 4d are schematic diagrams of the structure of the controllable diameter support.
[0012] Figure 5a , 5b 5c and 5d are structural schematic diagrams of different embodiments of the controllable diameter support;
[0013] Figure 6a , 6b Schematic diagrams of different embodiments of the controllable diameter support;
[0014] Figure 7 This is a structural diagram illustrating the connection method of the first connecting line between the wave loop and the polygonal loop.
[0015] Figure 8 This is a structural diagram of the first coverage area and the first bare area;
[0016] Figure 9 This is a schematic diagram showing the planar visual position distribution of the developing structure on the first bare region.
[0017] Figure 10 This is a schematic diagram showing the three-dimensional positional distribution of the developing structure on the first bare region.
[0018] Figure 11This is a diagram showing the positional relationship between the connecting membrane and the covering membrane.
[0019] Figure 12 This is a schematic diagram of the second connection method between the first connecting line and the polygonal loop;
[0020] Figure 13 This is a schematic diagram showing the position of the spiral structure on the self-expanding support.
[0021] Figure 14 This is a schematic diagram of a spiral structure;
[0022] Figure 15 This is a structural diagram illustrating the connection method of the second connecting line between adjacent polygonal circles.
[0023] Figure 16 This is a schematic diagram of the second connection method between adjacent polygonal circles;
[0024] Figure 17 This is a schematic diagram of a film-coated scaffold according to Embodiment 3. Detailed Implementation
[0025] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.
[0026] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "inner," "outer," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0027] Example 1
[0028] like Figure 1As shown, the coating support provided in this embodiment is a TIPS coating support. The TIPS coating support includes a support frame 1 and a cover film 2 disposed on the support frame 1. The support frame 1 includes a controllable diameter support 11 and a self-expanding support 12. The self-expanding support 12 is connected to both ends of the controllable diameter support 11 in the axial direction. A first connector is provided between the self-expanding support 12 and the controllable diameter support 11. The first connector includes a first connecting line 3. The flexibility of the first connector is greater than that of the controllable diameter support 11 and the self-expanding support 12. In other embodiments, only one end of the controllable diameter support 11 in the axial direction is connected to the self-expanding support 12. In some embodiments, a second connector can be provided between the first connector and the controllable diameter support 11 or the self-expanding support 12 to change the flexibility of the coating support.
[0029] In this embodiment, a gap is provided between the self-expanding support 12 and the controllable diameter support 11, and the self-expanding support 12 and the controllable diameter support 11 are connected by a first connector composed of a first connecting line 3. When the TIPS covered stent is in a compressed state, the gap between the opposite ends of the self-expanding support 12 and the controllable diameter support 11 is compressed. Since the flexibility of the first connector is greater than that of the controllable diameter support 11 and the self-expanding support 12, the first connector will contract and bend between the controllable diameter support 11 and the self-expanding support 12. When the TIPS covered stent is released, the self-expansion of the self-expanding support 12 will not directly exert a radial tensile force on the controllable diameter support 11, but will stretch the first connector from a wrinkled state to an extended state. This not only avoids the radial dimension of the controllable diameter support 11 from gradually increasing with the self-expansion of the self-expanding support 12, but also improves the flexibility between the two, thereby enhancing the ability of the TIPS covered stent to adapt to the shape of blood vessels.
[0030] like Figure 2As shown, the working principle of the TIPS covered stent in this embodiment is as follows: it is used to establish a channel between the hepatic vein a and the portal vein b through the liver, thereby reducing the high pressure caused by poor blood flow at the portal vein b. It establishes a channel of appropriate diameter through its own expansion and contraction characteristics for blood drainage. The two self-expanding supports 12 are placed in the hepatic vein a and portal vein b respectively, serving to connect the covered membrane within the liver parenchyma. To prevent the movement of the liver and blood vessels from closing the openings of the covered membrane 2, the self-expanding supports 12 are in the form of bare stents without membranes. Therefore, it can minimize the impact on the existing blood flow in the hepatic vein a and portal vein b, reducing the occurrence of acute liver failure caused by pressure reduction due to obstruction of blood flow into the liver. The controllable diameter support 11 in the middle has a certain plastic deformation capacity, thus acting like a valve. By adjusting the diameter of the controllable diameter support 11, the blood flow through the entire TIPS covered stent is controlled. When in use, the covering membrane 2 is placed inside the liver parenchyma, which serves to isolate bile leakage and prevent the liver parenchyma from proliferating into the support body. Because the liver secretes bile and the liver parenchyma tends to grow inward when damaged, the covering membrane 2 is applied to the support body 11 with a controllable diameter, i.e. the segment covering the liver parenchyma. The covering membrane 2 can completely prevent the penetration of bile and tissue.
[0031] The procedure for using the TIPS covered stent in this embodiment is as follows: After the TIPS covered stent is implanted into the liver, the self-expanding supports 12 at both ends expand for positioning. Due to the gap between the self-expanding supports 12 and the controllable diameter supports 11 and the first connecting line 3, the outer diameter of the controllable diameter supports 11 in the middle section remains unchanged. Then, the controllable diameter supports 11 are expanded to a smaller diameter using balloon dilation. If the reduction in blood pressure in the portal vein b is still insufficient, the controllable diameter supports 11 can be expanded again using balloon dilation. Due to the plastic deformation characteristics, the enlarged diameter will remain almost unchanged, increasing the blood flow and further reducing pressure. By repeating the above operation, the doctor only needs to change the balloon to a different size to achieve precise pressure control.
[0032] In this embodiment, the first connector can be one or a combination of a film, a bare support, a film-coated support, and a coil. The coil can be a single, closed loop of wire, with the self-expanding support 12 and the controllable diameter support 11 respectively positioned on opposite sides of the coil's axial direction, and the self-expanding support 12 and the controllable diameter support 11 fixedly arranged circumferentially with the coil. Alternatively, the coil can be composed of multiple circumferentially distributed loops of wire or filament, with no connection between adjacent loops or filaments, and both ends of the loops or filaments fixedly connected to the ends of the self-expanding support 12 and the controllable diameter support 11.
[0033] The flexibility of the self-expanding support 12, the controllable diameter support 11, and the first connector was compared using a three-point bending test method, the specific steps of which are as follows:
[0034] (1) Select a section of each of the self-expanding support 12, the controllable diameter support 11 and the first connecting piece with the same axial length;
[0035] (2) Place the two ends of each segment on the support rollers of the three-point bending test machine in sequence. The axial direction of each segment is perpendicular to the axial direction of the support rollers at both ends. Operate the force-applying rollers of the three-point bending test machine to press down the midpoints of the three segments by the same distance.
[0036] (3) Read the pressure values measured when the three sections are pressed down the same distance in sequence.
[0037] The pressure values measured using the above method are compared as follows: the pressure values of the controllable diameter support 11 and the self-expanding support 12 are both greater than the pressure value of the first connector. Since the greater the pressure, the worse the flexibility, and the lower the pressure, the better the flexibility, the first connector is more flexible than the self-expanding support 12 and the controllable diameter support 11.
[0038] like Figure 1 As shown, the flexibility of the self-expanding support 12 is greater than that of the controllable diameter support 11. A covering membrane 2 is connected to the end of the self-expanding support 12 closest to the controllable diameter support 11. Since the length of the liver parenchyma segment to be covered for the same patient is fixed, the length of the covering membrane 2 is also fixed. If the covering membrane 2 is connected to the end of the self-expanding support 12 closest to the controllable diameter support 11, the axial length of the controllable diameter support 11 needs to be shortened accordingly, and the axial length of the self-expanding support 12 needs to be extended towards the controllable diameter support 11. This increases the proportion of the covering membrane supported by the self-expanding support 12 and decreases the proportion of the covering membrane supported by the controllable diameter support 11. Because the flexibility of the self-expanding support 12 is greater than that of the controllable diameter support 11, the combination of the more flexible self-expanding support 12 and the covering membrane 2 effectively improves the flexibility of the stent covering the liver parenchyma segment. This prevents the stent from straightening the blood vessel over time and better adapts to channels with varying degrees of curvature within the liver. In addition, the covering membrane 2 is made of elastic polymer materials such as expanded polytetrafluoroethylene, polyester fiber, or polyurethane.
[0039] like Figure 3As shown, the self-expanding support 12 is a cylindrical structure composed of multiple wave rings 13 in the axial direction. Multiple wave bands 131 are periodically distributed on the wave rings 13. Each wave band 131 includes two adjacent support rods 1310. The two adjacent support rods 1310 are connected to each other to form the wave crest 1311 or wave trough 1312 of the wave ring 13. Adjacent wave rings 13 are connected to each other through the wave crest 1311 and wave trough 1312 of the wave band 131.
[0040] In this embodiment, the controllable diameter support 11 includes at least one polygonal ring, which comprises multiple polygonal structures connected sequentially in the circumferential direction. Each polygonal structure has at least four sides. Within the same polygonal ring, adjacent polygonal structures are connected diagonally or share the same side. Figure 4a , Figure 4b , Figure 4c and Figure 4d As shown, the polygonal structure includes quadrilateral structures 141, and multiple quadrilateral structures 141 form a quadrilateral ring 14. Adjacent quadrilateral structures 141 are connected by diagonals 1410. Figure 4a In the quadrilateral structure 141, the two corresponding corners 1411 / 1412 in the axial direction are far apart from each other; Figure 4b and Figure 4c In the quadrilateral structure 141, corresponding corners 1411 / 1412 in the axial direction are close to each other, and corresponding corners 1411 / 1412 in the axial direction of the quadrilateral structure 141 in the same quadrilateral ring can move closer to each other in the same direction (e.g., Figure 4b ), or they can approach in different directions (e.g. Figure 4c ); Figure 4d In the quadrilateral structure 141, the corresponding two corners 1411 / 1412 in the axial direction are far apart, while the corresponding two corners 1411 / 1412 in the axial direction are close together. In this embodiment, any corner of the quadrilateral structure 141 can be set as a rounded corner structure.
[0041] like Figure 5a , Figure 5b , Figure 5c and Figure 5d As shown, in another embodiment, the polygonal structure includes hexagonal structures 151, and multiple hexagonal structures 151 form a hexagonal ring 15, with adjacent hexagonal structures sharing the same side 1510. Figure 5a In the hexagonal structure 151, the two corresponding angles 1511 / 1512 in the axial direction are far apart from each other; Figure 5bIn the hexagonal structure 151, the corresponding two corners 1511 / 1512 in the axial direction are close to each other, and the corresponding two corners 1511 / 1512 of the hexagonal structure 151 in the same hexagonal ring can move closer to each other in the same direction (e.g., Figure 5b ), or they can approach in different directions (e.g. Figure 5c ); Figure 5d In the partial hexagonal structure 151, the corresponding two corners 1511 / 1512 in the axial direction are far apart, while the corresponding two corners 1511 / 1512 in the axial direction are close together. In this embodiment, any corner of the hexagonal structure 151 can be set as a rounded corner structure.
[0042] like Figure 6a As shown, in some other embodiments, the polygonal structure includes a pentagonal structure 161, with multiple pentagonal structures 161 forming a pentagonal ring 16, and adjacent pentagonal structures 161 sharing the same side 1610; or, as... Figure 6b As shown, the polygonal structure includes a heptagonal structure 171, and multiple heptagonal structures 171 form a heptagonal ring 17. Adjacent heptagonal structures 171 share the same side 1710. The way polygonal structures with other numbers of sides are connected is similar to the above method, and will not be described in detail here.
[0043] like Figure 7 As shown, the first connecting line 3 can be set between the band 131 and the quadrilateral structure 141 or the hexagonal structure 151. The crests 1311 or troughs 1312 of the band 13, the corners of the quadrilateral structure 141 (or hexagonal structure 151), and the different apex angles of the connection between the two quadrilateral structures 141 (or hexagonal structures 151) can respectively serve as fixed points for the first connecting line 3 to provide force, so that the combination of the self-expanding support 12 and the controllable diameter support 11 has both high support strength and a certain degree of flexibility, thus having excellent adaptability when adapting to curved channels.
[0044] The waveband 13 of the self-expanding support 12 can be made of nickel-titanium alloy, which can quickly expand and adhere to the blood vessel wall after release. The overlapping cylindrical structure can provide the waveband 131 with the freedom of displacement when the self-expanding support 12 bends, so that the self-expanding support 12 has excellent flexibility. Furthermore, the waveband 131 of the self-expanding support 12 is open-loop. Taking one of the circulating wavebands 131 as an example, radial deformation occurs only at one corner, which has the characteristics of easy bending deformation and good flexibility.
[0045] In this embodiment, the multiple quadrilateral structures 141 distributed circumferentially upward in the controllable diameter support 11 are made of stainless steel, cobalt-chromium alloy, or other metals with a certain plastic deformation capacity by laser cutting. The superior plastic deformation capacity of these metals, as well as the work hardening generated during the plastic deformation process, enable the final diameter to effectively resist the compression of the stent caused by the movement of the liver. Furthermore, the absence of superelasticity in these metals also avoids continuous chronic external forces. If the quadrilateral structure 141 is to deform, all four corners need to deform simultaneously, which is difficult to achieve. Therefore, the design of the quadrilateral structure 141 significantly improves the support strength, thereby effectively maintaining the adjusted diameter and better controlling the diameter of the controllable diameter support 11, preventing the stent diameter from deforming later and making it difficult to control the flow of blood. Similarly, the multiple hexagonal structures 151 distributed upwards around the hexagonal ring 15 are made of stainless steel, cobalt-chromium alloy and other metals with a certain plastic deformation capability by laser cutting. If the hexagonal structure 151 is to deform, all six corners need to deform at the same time. The bending deformation is difficult. Therefore, the design of the hexagonal structure 151 also significantly improves the support strength, so that the adjusted diameter can be effectively maintained, preventing the stent from being squeezed and deformed in the later stage, which would make it difficult to control the blood flow through it.
[0046] like Figure 7 As shown, the crests of the polygonal ring (e.g., quadrilateral ring 14 or hexagonal ring 15) after the controllable diameter support 11 is extended and the troughs 1312 of the wave ring 13 after the self-expanding support 12 is extended are arranged circumferentially at intervals. The first connecting line 3 is wound around the crests of the polygonal ring and the troughs 1312 of the wave ring 13 in the circumferential direction. And / or, the troughs of the polygonal ring after the controllable diameter support 11 is extended and the crests 1311 of the wave ring 13 after the self-expanding support 12 is extended are arranged circumferentially at intervals. The first connecting line 3 is wound around the troughs of the polygonal ring and the crests 1311 of the wave ring 13 in the circumferential direction.
[0047] It should be noted that, in the embodiments of this utility model, the crests of the polygonal rings (e.g., quadrilateral ring 14 or hexagonal ring 15) can be understood as the interior angles 1411 / 1412 / 1511 / 1512 that face the same direction as the crests 1311 of the ring 13, or the apex angle 14101 of the connection 1410 between adjacent polygonal structures that faces the same direction as the crests 1311 of the ring 13; the troughs of the polygonal rings (e.g., quadrilateral ring 14 or hexagonal ring 15) can be understood as the interior angles 1411 / 1412 / 1511 / 1512 that face the same direction as the troughs 1312 of the ring 13, or the apex angle 14102 of the connection 1410 between adjacent polygonal structures that faces the same direction as the troughs 1312 of the ring 13.
[0048] The above configuration can improve the fit between the controllable diameter support 11 and the self-expanding support 12, thereby increasing the space utilization of the gap between them. Furthermore, the first connecting line 3 is wound around the peaks and valleys of the polygonal ring and the peaks and valleys of the ring in the circumferential direction, which is more conducive to providing space for the controllable diameter support 11 and the self-expanding support 12 to rotate axially with each other.
[0049] In this embodiment, the first connecting line 3 is made of PET or PTFE wire, which has the properties of being soft but having high tensile strength. While ensuring the connection strength between the controllable diameter support 11 and the self-expanding support 12, it effectively improves the flexibility between the two.
[0050] like Figure 8 As shown, the self-expanding support 12 includes a first covering area 111 and a first bare area 112 connected axially. The first covering area 111 is connected to a covering membrane 2 and is closer to the controllable diameter support 11 than the first bare area 112. The axial length of the first covering area 111 is greater than the axial length of the controllable diameter support 11. Making the axial length of the first covering area 111 greater than the axial length of the controllable diameter support 11 increases the proportion of the covering membrane 2 supported by the self-expanding support 12, thereby improving the flexibility of the stent covering the liver parenchyma segment. Retaining a portion of the first bare area 112 reduces the proportion of the implanted covering membrane 2, minimizing the impact on existing blood flow in the hepatic vein a and portal vein b, allowing the liver to receive adequate blood supply, and reducing the risk of acute liver failure due to partial pressure caused by obstruction of blood flow into the liver. In some embodiments, the self-expanding support 12 may further include a second covering area and a second bare area, which are closer to or further away from the controllable diameter support 11 than the first bare area 112.
[0051] like Figure 8 As shown, both ends of the controllable diameter support 11 are connected to self-expanding supports 12 in the axial direction, and the lengths of the first bare areas 112 of the two self-expanding supports 12 may be unequal. With self-expanding supports 12 at both ends of the controllable diameter support 11 in the axial direction, the first bare areas 112 of the self-expanding supports 12 do not obstruct the flow of blood in the hepatic vein and portal vein, ensuring normal blood supply to the liver. They also serve to position and fix the entire TIPS covered stent. Since the length of the first bare area 112 needs to be designed according to different liver anatomical characteristics, the lengths of the first bare areas 112 of the two controllable diameter supports 11 may be unequal.
[0052] like Figure 9 and Figure 10As shown, several imaging structures 5 are circumferentially distributed at both the end of the first bare area 112 away from the first covered area 111 and the end of the first covered area 111 near the first bare area 112. Adjacent or spaced imaging structures 5 can overlap in the axial direction perpendicular to the self-expanding support 12. The presence of imaging structures 5 at both ends of the first bare area 112 away from the first covered area 111 and the first covered area 111 near the first bare area 112 facilitates simultaneous observation of the positions of the ends of the first bare area 112 and the covered area within the blood vessel. Furthermore, the circumferential distribution of these imaging structures 5 improves imaging effects in all observation directions.
[0053] like Figure 11 As shown, the covering membrane 2 includes a connecting membrane 21 connected between the controllable diameter support 11 and the self-expanding support 12. The axial length of the connecting membrane 21 in the extended state is the difference between the radius of the self-expanding support 12 in the extended state and the radius of the controllable diameter support 11 in the non-extended state. The first connecting line 3 is fixed to the connecting membrane 21, and the axial length of the first connector is equal to the axial length of the connecting membrane 21. When the TIPS covering support is released, the self-expanding support 12 rapidly expands to its extended state. Since the axial length of the connecting membrane 21 in its extended state is the difference between the radius of the self-expanding support 12 in its extended state and the radius of the controllable diameter support 11 in its non-extended state, the axial distance between the self-expanding support 12 and the controllable diameter support 11 will be zero after the connecting membrane 21 is radially stretched by the self-expanding support 12. This ensures that the connecting membrane 21 occupies the minimum proportion of the covering membrane 2 length while maintaining connection between the two supports, preventing the connecting membrane 21 from being too long and causing axial displacement of the controllable diameter support 11 between the two self-expanding supports 12, or the connecting membrane 21 from being too short. The expansion of the self-expanding support 12 affects the radial tension of the controllable diameter support 11; fixing the first connecting line 3 to the connecting membrane 21 provides support for the connecting membrane 21, improves the tensile strength and deformation resistance of the connecting membrane 21, and at the same time, fixing the two together can prevent the first connecting line 3 from getting tangled with other structures during the expansion and contraction of the bracket; making the axial length of the first connector equal to the axial length of the connecting membrane 21 reduces the deformation caused by the connection membrane 21 and the first connector, maintains the original flatness of the connecting membrane 21 to the maximum extent, and can effectively maintain the original axial length of the connecting membrane 21, preventing the connecting membrane 21 from being stretched, deformed or compressed and wrinkled.
[0054] It should be noted that the unextended state of the controllable diameter support 11 refers to the state of the controllable diameter support 11 before it is expanded by the balloon after being compressed in the conveying device or released. When the controllable diameter support 11 is compressed in the conveying device, the sheath core is inserted inside the controllable diameter support 11, and the balloon is integrated on the sheath core. When the balloon does not expand, the controllable diameter support 11 will not be expanded by the balloon. When the controllable diameter support 11 is released from the conveying device, the sheath core is still inserted inside the controllable diameter support 11. If the balloon does not expand, the controllable diameter support 11 will still not expand. Therefore, whether the controllable diameter support 11 is compressed in the conveying device or released, the controllable diameter support 11 is in a compressed state without expansion.
[0055] When the controllable diameter support 11 is expanded using a balloon (in this embodiment, the diameter of the controllable diameter support 11 after balloon expansion is less than or equal to the diameter of the self-expanding support 12), the end of the connecting membrane 21 connected to the controllable diameter support 11 expands, and the axial distance between the controllable diameter support 11 and the self-expanding support 12 lengthens. At this time, the connecting membrane 21 forms a funnel shape or a straight cylinder between the controllable diameter support 11 and the self-expanding support 12. Since there is no support frame inside the connecting membrane 21, its flexibility is better than that of the controllable diameter support 11 and the self-expanding support 12. The shape of the connecting membrane 21 can change with the flow of blood, and the force of blood on the inner wall of the connecting membrane will be reduced. Therefore, the connecting membrane 21 can buffer the blood flowing between the controllable diameter support 11 and the self-expanding support 12, and the blood can flow more smoothly between the controllable diameter support 11 and the self-expanding support 12, effectively reducing the formation of eddies and avoiding the formation of thrombi.
[0056] In this embodiment, the connecting membrane 21 includes an outer membrane and an inner membrane, with a first connecting line 3 disposed between the outer and inner membranes. The first connecting line 3 forms a fibrous structure within the connecting membrane 21, reinforcing its strength and protecting it, further improving the connection strength between the self-expanding support 12 and the controllable diameter support 11. Furthermore, in this embodiment, the inner and outer membranes are connected by adhesive bonding or hot pressing, securely encapsulating the support within and forming a reliable, non-separable whole.
[0057] Furthermore, in this embodiment, such as Figure 12As shown, since the number of crests (or troughs) of the polygonal ring (e.g., quadrilateral ring 14 or hexagonal ring 15) is consistent with the number of crests (or troughs) of the wave ring 13, several first connecting lines 3 can be provided. These several first connecting lines 3 are distributed circumferentially. The two ends of each first connecting line 3 are respectively connected to the crests of the polygonal ring (e.g., quadrilateral ring 14 or hexagonal ring 15) and the crests of the wave ring 13, and / or, the two ends of each first connecting line 3 are respectively connected to the troughs of the polygonal ring (e.g., quadrilateral ring 14 or hexagonal ring 15) and the crests of the wave ring 13, and / or, the two ends of each first connecting line 3 are respectively connected to the crests of the polygonal ring (e.g., quadrilateral ring 14 or hexagonal ring 15) and the troughs of the wave ring 13, and / or, the two ends of each first connecting line 3 are respectively connected to the troughs of the polygonal ring (e.g., quadrilateral ring 14 or hexagonal ring 15) and the troughs of the wave ring 13.
[0058] like Figure 13 As shown, the self-expanding support 12 also includes a spiral structure 6. The spiral structure 6 is woven into the self-expanding support 12 by spirally winding it along the axial direction to form a keel. The formation process of the spiral structure 6 is as follows:
[0059] like Figure 14 As shown, the self-expanding support 12 is woven from one end to the other by a single filament structure 7 on a braiding mandrel 8. Several braiding needles 9 are radially spaced on the braiding mandrel 8. The filament structure 7 is wound circumferentially around the braiding mandrel 8 to form wave loops 13. The filament structure 7 spirally winds around the vertically distributed braiding needles 9 to form wave segments 131. The wave loops 13 are formed by the filament structure 7 winding circumferentially from the first wave trough 132 to form several closed loops of wave segments 131, then extending along the rising direction of the next first wave peak 133, passing through the second wave trough 134 of the adjacent wave loop 13 to the second wave peak 135, and continuing to wind. The filament structure 7 between the first wave trough 132 and the second wave trough 134 forms a spiral segment 61. Several spiral segments 61 are sequentially joined end-to-end to form a spiral structure 6. The spiral structure 6, by spirally winding along the axial direction on the self-expanding support 12, can uniformly enhance the radial support force of the self-expanding support 12.
[0060] Example 2
[0061] The TIPS coated stent in this embodiment is basically the same as that in Embodiment 1, except that:
[0062] like Figure 15As shown, several polygonal rings are arranged axially. The crests of one polygonal ring and the troughs of adjacent polygonal rings are circumferentially spaced apart. Adjacent polygonal rings are connected by a second connecting line 4. The polygonal rings can be quadrilateral or hexagonal. Specifically, for example, two or more quadrilateral rings 14 are arranged axially, such as three. The crests of one quadrilateral ring 14 and the troughs of adjacent quadrilateral rings 14 are circumferentially spaced apart. A second connecting line 4 is provided between adjacent quadrilateral rings 14. In this embodiment, the material of the second connecting line 4 is PET or PTFE wire, which has the properties of being soft but having high tensile strength, effectively improving the flexibility between the quadrilateral rings 14 while ensuring the connection strength between them.
[0063] When the support strength requirement is high, the number of quadrilateral rings 14 in the axial direction of the controllable diameter support body 11 is increased to improve the support force of the support within the corresponding length. Since the crests of a quadrilateral ring 14 and the troughs of adjacent quadrilateral rings 14 are arranged circumferentially at intervals, the second connecting line 4 is used to wrap around the crests and troughs of adjacent quadrilateral rings 14 in a circumferential manner to avoid loss of flexibility. This allows multiple quadrilateral rings 14 to have both high support strength and a certain degree of flexibility, thus providing excellent compliance when adapting to curved channels.
[0064] Furthermore, in this embodiment, such as Figure 16 As shown, the second connecting line 4 can also be configured as several lines, which are distributed circumferentially. The two ends of each second connecting line 4 are respectively connected to the crests of the adjacent quadrilateral 14, and / or the two ends of each second connecting line 4 are respectively connected to the troughs of the adjacent quadrilateral 14.
[0065] Example 3
[0066] The TIPS coated stent in this embodiment is basically the same as that in Embodiment 1 or Embodiment 2, except that:
[0067] Several polygonal rings are arranged axially, and the crest of one polygonal ring is fixedly connected to the trough of an adjacent polygonal ring. The polygonal rings can be quadrilateral or hexagonal. Specifically, for example, ... Figure 17 As shown, there are two or more (e.g., three) quadrilateral rings 14 in the axial direction, with the crest of one quadrilateral ring 14 fixedly connected to the trough of the adjacent quadrilateral ring 14. In some embodiments, a portion of the crest of one quadrilateral ring 14 is fixedly connected to a portion of the trough of the adjacent quadrilateral ring 14.
[0068] When a patient with severe cirrhosis has a greater need, the peaks and troughs of three adjacent quadrilateral rings 14 are fixedly connected respectively. This can be done by welding or by connecting them into one piece during manufacturing, without any gaps in the middle, increasing the difficulty of deformation and thus improving the support strength.
[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0070] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.
Claims
1. A covered stent comprising a support frame (1) and a covering film (2) provided to the support frame (1), characterized in that, The support frame (1) comprises a controllable diameter support body (11) and a self-expanding support body (12), at least one side of the controllable diameter support body (11) in the axial direction is connected with the self-expanding support body (12), wherein the controllable diameter support body (11) comprises at least one polygonal ring, the polygonal ring comprises a plurality of polygonal structures connected in sequence in the circumferential direction, and the number of sides of the polygonal structure is at least four; in the same polygonal ring, adjacent polygonal structures are connected by diagonal connection or share the same side.
2. The stent graft of claim 1, wherein: The first connecting piece is provided between the self-expanding support body (12) and the controllable diameter support body (11), and the flexibility of the first connecting piece is greater than the flexibility of any one of the controllable diameter support body (11) and the self-expanding support body (12).
3. The stent graft of claim 1, wherein: The self-expanding support body (12) comprises a first covered area (111) and a first bare area (112) connected in the axial direction, the first covered area (111) is connected with the covering film (2), and is closer to the controllable diameter support body (11) than the first bare area (112).
4. The stent graft of claim 3, wherein: The first bare area (112) is away from one end of the first covered area (111) and one end of the first covered area (111) close to the first bare area (112), and a plurality of developing structures (5) are distributed in the circumferential direction.
5. The stent graft of claim 2, wherein: The covering film (2) comprises a connecting film (21) connected between the controllable diameter support body (11) and the self-expanding support body (12), and the axial length of the connecting film (21) in the stretched state is the difference between the radius of the self-expanding support body (12) in the stretched state and the radius of the controllable diameter support body (11) in the non-stretched state.
6. The stent graft of claim 5, wherein: The connecting film (21) comprises an outer film and an inner film, and the first connecting piece comprises a first connecting wire (3), and the first connecting wire (3) is arranged between the outer film and the inner film.
7. The stent graft of claim 2, wherein: The self-expanding support body (12) comprises a plurality of wave coils (13) arranged in the axial direction, the wave crests of the polygonal ring after the controllable diameter support body (11) is stretched and the wave troughs of the wave coil (13) after the self-expanding support body (12) is stretched are arranged in the circumferential direction in sequence, and / or the wave troughs of the polygonal ring after the controllable diameter support body (11) is stretched and the wave crests of the wave coil (13) after the self-expanding support body (12) is stretched are arranged in the circumferential direction in sequence.
8. The stent graft of claim 7, wherein: The first connecting piece is wound through the wave crests of the polygonal ring and the wave troughs of the wave coil (13) in the circumferential direction in sequence, and / or the first connecting piece is wound through the wave troughs of the polygonal ring and the wave crests of the wave coil (13) in the circumferential direction in sequence.
9. The stent graft of claim 1, wherein: The polygonal ring is provided in the axial direction, and the wave crests of one polygonal ring and the wave troughs of the adjacent polygonal ring are arranged in the circumferential direction in sequence, and the adjacent polygonal rings are connected by a second connecting wire (4).
10. The stent graft of claim 1, wherein: The polygonal ring is provided in the axial direction, and one wave crest of one polygonal ring and the adjacent polygonal ring are fixedly connected.