Stent for tips surgery

Abstract

A stent for TIPS surgery, comprising a first stent body (1) and a second stent body (2). When in use, the first stent body (1) is sleeved outside the second stent body (2) so as to control the self-expansion range of the second stent body (2). The first stent body comprises a first connecting body (11), an intermediate connecting body (12), and a second connecting body (13). The second stent body (2) is woven from a monofilament memory alloy, and the second stent body (2) comprises a first section (21) and a second section (22) connected to each other, the first section being a woven spiral structure, and the second section being a woven self-locking structure.

Description

A TIPS surgical stent Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a pressure-dividing stent for TIPS. Background Technology

[0002] Portal hypertension is a disease characterized by obstructed blood flow and stagnation in the portal venous system, leading to increased pressure and resulting in a range of clinical manifestations, including splenomegaly, hypersplenism, esophageal and gastric varices, hematemesis, and ascites. Transjugular intrahepatic portosystemic shunt (TIPS), as an interventional treatment for portal hypertension, is gradually becoming a primary clinical approach. TIPS involves creating an artificial blood diversion channel between the portal vein and hepatic veins through interventional surgery. This connects the hypertensive portal vein to the hepatic veins, diverting some of the portal vein's blood flow to reduce portal hypertension, thereby controlling and preventing esophageal and gastric variceal rupture and bleeding, and promoting ascites absorption.

[0003] However, TIPS surgery has limitations in its application, and the risk of hepatic encephalopathy still restricts its widespread use. The increased incidence of hepatic encephalopathy is due to the fact that during TIPS surgery, the establishment of the shunt allows nitrogenous substances in the blood to enter the systemic circulation directly without being detoxified by the liver, leading to elevated blood ammonia levels. This increased ammonia concentration causes an imbalance between excitatory and inhibitory neurotransmitters in the brain, manifesting as either mental excitation or inhibition. Therefore, the size of the shunt is related to the risk of hepatic encephalopathy; a larger shunt increases the risk, while a shunt that is too small may not adequately reduce portal vein pressure and could still cause re-rupture and bleeding of the esophageal and gastric fundus veins. Therefore, a stent that allows for flexible adjustment of the shunt size during or after surgery is needed. This would allow for reasonable control of the shunt size based on the actual situation, reducing portal hypertension while effectively minimizing the risk of hepatic encephalopathy. Technical issues

[0004] In view of this, the present invention provides a stent for TIPS surgery. Technical solutions

[0005] A TIPS surgical stent includes a first stent body and a second stent body. In use, the first stent body is sleeved on the outside of the second stent body to control the self-expansion range of the second stent body.

[0006] The first support body includes a first connector, an intermediate connector, and a second connector. There are two first connectors, located at opposite ends of the first support body. The first connector and the second connector, as well as two adjacent second connectors, are connected by the intermediate connector. The intermediate connector is an N-shaped connection. Both the first connector and the second connector are loops consisting of several W-shaped units connected end to end. Each W-shaped unit of the first connector includes one connection point with the intermediate connector. Each W-shaped unit of the second connector includes two connection points with the intermediate connector, located on the upper and lower sides of the W-shaped unit.

[0007] The second support body is woven from a single filament shape memory alloy, and the second support body includes a first segment and a second segment connected to each other. The first segment is a woven spiral structure, the second segment is a woven self-locking structure, and the first segment is provided with a coating structure. The coating structure of the first segment includes an inner coating layer, an intermediate layer and an outer coating layer, and the inner coating layer is made of at least two coating materials.

[0008] In a further optimization of the technical solution of the present invention, the first support body is made of stainless steel or cobalt-chromium alloy, and the second support body is woven from a single nickel-titanium alloy wire.

[0009] In a further optimization of the technical solution of the present invention, both the inner and outer film layers are expanded polytetrafluoroethylene (ePTFE) materials, and the intermediate layer is fluorinated ethylene propylene.

[0010] In a further optimization of the technical solution of the present invention, the length of the first segment accounts for 50%-90% of its total length, and the length of the first support body is 40%-75% of the length of the first segment.

[0011] In a further optimization of the technical solution of the present invention, the intermediate layer is disposed on the first section of the second support body by means of a hot-melt or adhesive process. Beneficial effects

[0012] By configuring the first stent body as a first connector, an intermediate connector, and a second connector, the length of the first stent body can be shortened to a negligible degree during expansion. Furthermore, the design of this structure, combined with its stainless steel or cobalt-chromium alloy material, facilitates mechanical diameter control. Under physiological conditions, it will not creep over a long period of time, effectively improving the stability of the TIPS surgical stent. Attached Figure Description

[0013] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0014] Figure 1 is a structural diagram of the TIPS surgical stent in use;

[0015] Figure 2 is a schematic diagram of the structure of the first support body;

[0016] Figure 3 is a schematic diagram of the structure of the first support body being introduced;

[0017] Figure 4 is a schematic diagram of the structure of the second support body.

[0018] In the diagram: A. Portal vein; B. Hepatic vein; C. Intrahepatic puncture;

[0019] 1. First support body; 11. First connecting body; 12. Intermediate connecting body; 13. Second connecting body;

[0020] 2. Second support body; 21. First segment; 22. Second segment. The best embodiment of the present invention

[0021] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail, but well-known methods, processes, procedures, and elements are not described in detail in order to avoid obscuring the essence of the present invention.

[0022] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0023] Unless the context explicitly requires it, the words "comprising," "including," or similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0024] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] Referring to Figures 1-4, this invention provides a TIPS surgical stent, including a first stent body 1 and a second stent body 2. When unfolded, both the first stent body 1 and the second stent body 2 are hollow tubular structures. In use, the first stent body 1 is fitted over the second stent body 2. The second stent body 2 is a self-expanding stent, capable of self-expanding to its maximum diameter after release. The first stent body 1 expands under external force, and once it expands to the required diameter, it limits the self-expansion range of the second stent body 2. This TIPS surgical stent primarily functions to divert blood from the portal vein to the hepatic vein through intrahepatic puncture, thereby reducing portal hypertension. However, because the ammonia content in the blood of the hepatic vein can trigger hepatic encephalopathy, a stable and flexibly mechanically controllable TIPS surgical stent is required.

[0026] In this technical solution, the first support body 1 is designed as three parts: a first connecting body 11, an intermediate connecting body 12, and a second connecting body 13. There are two first connecting bodies 11, located at both ends of the first support body 1. The first connecting body 11 and the second connecting body 13, as well as two adjacent second connecting bodies 13, are connected by the intermediate connecting body 12. The intermediate connecting body 12 is an N-shaped combination, which can increase the straight space and maximize the effective length of the diversion channel. The first connecting body 11 and the second connecting body 13 are both rings consisting of several W-shaped units connected end to end. Each W-shaped unit of the first connecting body includes one connection point 14 with the intermediate connecting body 12. Each W-shaped unit of the second connecting body 13 includes two connection points 14 with the intermediate connecting body 12, and the two connection points 14 are located on the upper and lower sides of the W-shaped unit, respectively. By setting the connection point 14 and its shape, the first stent body 1 can be shortened to a small extent in the length direction when it expands. The degree of shortening is almost negligible. Moreover, by designing this structure and using its stainless steel or cobalt-chromium alloy materials, the diameter can be mechanically adjusted. Under physiological conditions, it will not creep over a long period of time, which effectively improves the stability of the TIPS surgical stent.

[0027] It should be noted that the first support body 1 is made of stainless steel or cobalt-chromium alloy by laser cutting. Laser cutting can increase the stability of the first support body 1 and ensure that the first support is a whole structure, thus ensuring its mechanical properties.

[0028] The second stent body 2 is woven from a single filament of shape memory alloy. By selecting a single filament, it can be wound to the distal end of the uncoated section and then back to the junction of the coated and uncoated sections, effectively preventing loose filament ends from being exposed outside the stent and posing a safety hazard during long-term use under physiological conditions. Preferably, the second stent body 2 is woven from nickel-titanium alloy wire. The second stent body 2 includes a first segment 21 and a second segment 22 connected to each other. The first segment 21 is a woven spiral structure, and by setting it into a spiral structure with alternating peaks and troughs, the first segment 21 of the second stent body 2 becomes more flexible. The second segment 22 is a woven self-locking structure or a locking structure, which can prevent the second segment 22 from excessively elongating in the overall longitudinal direction. A coating structure is provided on the first segment 21, and the coating structure of the first segment 21 includes an inner coating layer, an intermediate layer, and an outer coating layer. The inner coating layer is made of at least two coating materials and is connected to the woven mesh of the first segment 21 through the coating materials, which can reduce the permeability of bile while ensuring flexibility and longitudinal strength. Preferably, the inner coating layer and the outer coating layer are both expanded polytetrafluoroethylene (ePTFE) material, and the intermediate layer is fluorinated ethylene propylene.

[0029] Preferably, the length of the first segment 21 accounts for 50%-90% of its total length, and the length of the first support body 1 is 40%-75% of the length of the first segment 21. This structural arrangement enables stable pressure distribution.

[0030] Preferably, the intermediate layer is sewn onto the first segment 21 of the second support body 2, and this sewing connection increases the stability of the coating. Alternatively, it can be applied to the first segment of the second support body using a hot-melt or adhesive process.

[0031] When using stents in TIPS surgery, the first stent body 1 is first inserted into the intrahepatic puncture site using an infusion system. Then, a suitable support balloon is selected to expand the inner diameter of the first stent body 1 to the first diameter (the minimum diameter to be expanded based on flow rate calculations). Next, the second stent body 2 is inserted, causing it to expand within the first stent body 1 until fully deployed. During insertion, the second segment 22 of the second stent body 2 can extend beyond the intrahepatic puncture channel, completing the initial insertion. It should be noted that after insertion, at least one pressure measurement should be performed to determine the pressure gradient between the portal vein and the hepatic vein or inferior vena cava. The diameter of the first stent body 1 can be adjusted accordingly based on the pressure readings. Alternatively, multiple pressure measurements and adjustments to the diameter of the first stent body 1 can be performed. For example, pressure measurements can be taken one day, one week, one month, or longer after the surgery, and the diameter of the first stent body 1 can be adjusted based on the measurement results.

[0032] The inner diameter (ID) of the first support body 1 is approximately 6 mm when unfolded and can expand to approximately 10 mm. In some examples, the inner diameter of the first support body 1 can expand normally from 12% to 40%. Of course, the structure of the first support body 1 designed in this technical solution can expand 40%-70% and remain stable within this range. The length of the second support body 2 is 6 cm-12 cm, and the total wall thickness is between 0.1 mm and 1 mm.

[0033] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A TIPS surgical stent, characterized in that, It includes a first support body and a second support body. In use, the first support body is sleeved on the outside of the second support body to control the self-expansion range of the second support body. The first support body includes a first connecting body, an intermediate connecting body, and a second connecting body. There are two first connecting bodies, located at opposite ends of the first support body. The first connecting body and the second connecting body, as well as two adjacent second connecting bodies, are connected by the intermediate connecting body. The intermediate connecting body is an N-shaped structure parallel to the axial direction of the first support body. Both the first connecting body and the second connecting body are rings composed of several W-shaped units connected end to end. Each W-shaped unit of the first connecting body includes one connection point with the intermediate connecting body. Each W-shaped unit of the second connecting body includes two connection points with the intermediate connecting body, and the two connection points are located on the upper and lower sides of the W-shaped unit, respectively. The second support body is woven from a single filament shape memory alloy, and the second support body includes a first segment and a second segment connected to each other. The first segment is a woven spiral structure, the second segment is a woven self-locking structure, and the first segment is provided with a coating structure. The coating structure of the first segment includes an inner coating layer, an intermediate layer and an outer coating layer, and the inner coating layer is made of at least two coating materials.

2. The TIPS surgical stent according to claim 1, characterized in that, The first support body is made of stainless steel or cobalt-chromium alloy, and the second support body is woven from a single nickel-titanium alloy wire.

3. The TIPS surgical stent according to claim 1, characterized in that, Both the inner and outer membrane layers are made of expanded polytetrafluoroethylene (ePTFE), and the intermediate layer is made of fluorinated ethylene propylene.

4. The TIPS surgical stent according to claim 1, characterized in that, The length of the first support body is 40%-75% of the length of the first segment.

5. The TIPS surgical stent according to claim 1, characterized in that, The intermediate layer is applied to the first section of the second support body using a hot-melt or adhesive process.

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