A microcatheter of variable stiffness

Abstract

The present application belongs to the technical field of medical devices, and particularly relates to a micro catheter with variable rigidity. The micro catheter with variable rigidity comprises a catheter, a handle and a balloon. The catheter has a device conveying cavity and a liquid filling cavity, the liquid filling cavity is arranged outside the device conveying cavity, and the balloon is arranged in the liquid filling cavity. The device conveying cavity is used for conveying devices, and the liquid filling cavity is used for conveying fluid to the balloon. The handle is arranged at the proximal end of the catheter, and the handle has a first luer joint and a second luer joint. The first luer joint is in communication with the liquid filling cavity, and the second luer joint is in communication with the device conveying cavity. The micro catheter with variable rigidity can adjust the rigidity according to requirements, and can balance the good bending performance and support performance.

Description

Technical Field

[0001] This invention belongs to the field of medical device technology, specifically relating to a microcatheter with variable stiffness. Background Technology

[0002] With the advancement of neurointerventional technology and consumables, interventional surgery is becoming an increasingly popular treatment option for stroke. During interventional surgery, catheters or interventional devices are typically delivered intravascularly. In neurointerventional procedures, a guiding catheter is generally used to establish a channel, and a distal catheter provides a flexible end to open the occluded vessel via aspiration or thrombectomy. For treating ischemic and hemorrhagic strokes involving tortuous intracranial vessels, distal catheters are used to deliver microcatheters and coils directly to the affected vessel.

[0003] For the treatment of severely tortuous blood vessels, it is necessary to pre-shape the tip of the interventional device (usually a microcatheter) while ensuring the distal end is relatively flexible to reach the target location. Once the distal end of the microcatheter reaches the target location, the device is delivered through the microcatheter and released at the site of the lesion. A relatively firm distal end of the microcatheter is required for more stable and precise device release. However, the pre-shaping of the microcatheter increases the interventional procedure time and the difficulty of the surgeon's operation, sometimes requiring multiple shaping attempts to reach the target location. The control of these catheters is highly dependent on the interventional physician's skill and requires a very high level of expertise.

[0004] Therefore, further improvements to existing technologies are needed. Summary of the Invention

[0005] The purpose of this invention is to provide a microcatheter with variable stiffness, which helps to solve or improve the problem that the distal end of existing microcatheters is difficult to achieve both good bending performance and support performance.

[0006] The variable-stiffness microcatheter of the present invention adopts the following technical solution: A variable-stiffness microcatheter includes: a catheter having an instrument delivery chamber and a fluid filling chamber, the fluid filling chamber being disposed outside the instrument delivery chamber, and a balloon being disposed within the fluid filling chamber; the instrument delivery chamber being used to deliver an instrument, and the fluid filling chamber being used to deliver fluid to the balloon; a handle being disposed at the proximal end of the catheter, the handle having a first Luer connector and a second Luer connector, the first Luer connector being connected to the fluid filling chamber; and the second Luer connector being connected to the instrument delivery chamber.

[0007] Preferably, the balloon is positioned at least near the distal end of the catheter.

[0008] Preferably, the balloon has a proximal opening and a distal sealing; at least the proximal end of the balloon is fixed to the inner wall of the liquid filling cavity.

[0009] Preferably, there are two liquid filling cavities, which are respectively located on opposite sides of the instrument delivery cavity.

[0010] Preferably, the catheter is composed of an inner tube, a reinforcing layer, and an outer tube; the instrument delivery cavity is the inner tube cavity; the liquid filling cavity is disposed on the wall of the outer tube and extends along the axial direction of the catheter, and the distal end of the liquid filling cavity is closed.

[0011] Preferably, the inner tube is made of PTFE; the reinforcing layer is made of stainless steel; and the outer tube is made of PEBAX with different hardnesses, with the hardness of the outer tube gradually decreasing from the proximal end to the distal end.

[0012] Preferably, the distal end of the catheter is further provided with a radiopaque ring.

[0013] Beneficial effects: The variable-stiffness microcatheter of this invention has excellent vascular bend-crossing ability when the balloon is not inflated, making it easier for interventional physicians to pass the catheter through severely tortuous blood vessels and solving the problem of difficult-to-cross tortuous blood vessels near lesions. After the catheter reaches the designated position, the balloon can be inflated under the pressure of the fluid by delivering fluid (e.g., saline) into the fluid filling lumen, increasing the support of the distal end of the catheter and preventing it from retracting when passing other instruments. This makes the instrument release more stable and the release position more precise, thereby reducing the risk of various complications and catheter instability during the operation. Attached Figure Description

[0014] Figure 1 A schematic diagram of the overall structure of a variable-hardness microcatheter provided in one embodiment of the present invention; Figure 2 An axial cross-sectional view of a variable-hardness microcatheter provided in one embodiment of the present invention; Figure 3 This is an enlarged structural schematic diagram of a liquid filling cavity provided in one embodiment of the present invention; Figure 4 A variable-hardness microcatheter provided in another embodiment of the present invention is coupled with Figure 2 Enlarged cross-sectional view of the location corresponding to AA in the middle section; Figure 5 A variable-hardness microcatheter provided in another embodiment of the present invention is coupled with Figure 2 Enlarged cross-sectional view of the location corresponding to BB in the middle.

[0015] Figure label: 1-Handle; 1(a)-First Luer connector; 1(b)-Second Luer connector; 2-Catheter; 2(a)-Instrument delivery chamber; 2(b)-Fluid filling chamber; 21-Inner tube; 22-Reinforcing layer; 23-Outer tube; 3-Balloon; 4-Iconizing ring. Detailed Implementation

[0016] The preferred embodiments of the present invention will now be described in detail with reference to examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and intent, and all such modifications and substitutions fall within the scope of protection claimed in the present invention.

[0017] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limiting this invention.

[0018] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0019] 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 technical features indicated. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include one or more features.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection or a connection that allows communication between the two components; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components, an indirect connection, or an interaction between two components.

[0021] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0022] In the following description of the variable-hardness microcatheter of the present invention, the end closer to the operator is called the proximal end, and the end farther from the operator is called the distal end.

[0023] To address the problem that existing microcatheters struggle to balance good bending performance and support at their distal ends, this invention provides a microcatheter with variable stiffness.

[0024] like Figure 1-5 The diagram shows the structure of the liquid-filled cavity 2(b) for clarity. Figure 2-3 Adopted with Figure 4-5 (Different radial dimension ratios), the variable stiffness microcatheter of this embodiment includes: a catheter 2, the catheter 2 having an instrument delivery chamber 2(a) and a liquid filling chamber 2(b), the liquid filling chamber 2(b) being disposed outside the instrument delivery chamber 2(a) (with the direction away from the central axis of the instrument delivery chamber 2(a) being considered as outside, and the direction close to the central axis of the instrument delivery chamber 2(a) being considered as inside), and a balloon 3 being disposed inside the liquid filling chamber 2(b); the instrument delivery chamber 2(a) is used to deliver an instrument (e.g., a stent, etc.), and the liquid filling chamber 2(b) is used to deliver fluid to the balloon 3 (one or more liquid filling chambers 2(b) can be provided as needed; multiple means two or more); a handle 1, the handle 1 being disposed at the proximal end of the catheter 2, the handle 1 having a first Luer connector 1(a) and a second Luer connector 1(b), the first Luer connector 1(a) being connected to the liquid filling chamber 2(b) (facilitating the delivery of fluid into the liquid filling chamber 2(b) or the balloon 3); the second Luer connector 1(b) being connected to the instrument delivery chamber 2(a) (facilitating the delivery of the instrument).

[0025] The variable-stiffness microcatheter of the present invention has good vascular bend-crossing ability when the balloon 3 (which may be a polymer balloon) is not inflated, making it easier for interventional physicians to pass the catheter 2 through severely tortuous blood vessels, and solving the problem of difficult to cross tortuous blood vessels near lesions; when the catheter 2 reaches the designated position, the balloon 3 can be inflated under the action of liquid pressure by delivering liquid (e.g., saline) into the liquid filling chamber 2 (b), which increases the support force of the distal end of the catheter 2, so that it does not retract when passing other instruments, and the release of instruments is more stable and the release position is more accurate, thereby reducing the risk of various complications and catheter instability during the operation.

[0026] In a preferred embodiment of the variable hardness microcatheter of the present invention, the balloon 3 is disposed at least near the distal end of the catheter 2 (i.e., the balloon 3 may be disposed only near the distal end of the catheter 2 to facilitate adjustment of the hardness of the distal end of the catheter 2, or the balloon 3 may be disposed at other locations of the catheter 2 as needed to facilitate adjustment of the hardness at other locations of the catheter 2).

[0027] In a preferred embodiment of the variable-stiffness microcatheter of the present invention, the proximal end of the balloon 3 has an opening and the distal end is sealed; at least the proximal end of the balloon 3 is fixed to the inner wall of the liquid filling chamber 2(b). The proximal opening of the balloon 3 allows for convenient injection of liquid into the balloon 3, facilitating the inflation of the balloon 3 as needed, thereby adjusting the stiffness (support performance) of the catheter 2. "At least the proximal outer wall of balloon 3 is fixed to the inner wall of the liquid filling cavity 2(b)" means that, except for the proximal opening of balloon 3, other positions of balloon 3 can also be fixed in the liquid filling cavity 2(b) (so that when there is no liquid in balloon 3, it will not adversely affect the flexibility of catheter 2 or reduce the bending ability of catheter 2), which helps to improve the stability of balloon 3 in the liquid filling cavity 2(b); by fixing the proximal outer wall of balloon 3 to the inner wall of liquid filling cavity 2(b) (preferably, the proximal end of balloon 3 is fitted and sealed to the inner wall of liquid filling cavity 2(b), it helps to allow liquid to fully enter balloon 3 and realize the inflation of balloon 3.

[0028] In a preferred embodiment of the variable stiffness microcatheter of the present invention, such as Figure 4-5 As shown, there are two liquid filling cavities 2(b), which are respectively located on the opposite side of the instrument delivery cavity 2(a) (the two liquid filling cavities 2(b) are arranged in parallel and are not connected to each other; "opposite side" means that the two liquid filling cavities 2(b) are symmetrical about the central axis of the catheter).

[0029] Accordingly, in order to facilitate the delivery of such Figure 4-5 The two liquid filling chambers 2(b) shown are respectively filled with liquid (e.g., physiological saline), and the first Luer connector 1(a) has a branch tube (not shown in the figure) which is connected to the two liquid filling chambers 2(b) respectively.

[0030] In a preferred embodiment of the variable stiffness microcatheter of the present invention, the catheter 2 is composed of an inner tube 21, a reinforcing layer 22 and an outer tube 23; the instrument delivery cavity 2(a) is the lumen of the inner tube 21; the liquid filling cavity 2(b) is disposed on the wall of the outer tube 23 and extends along the axial direction of the catheter 2 (from the proximal end to the distal end), and the distal end of the liquid filling cavity 2(b) is closed (to prevent the liquid in the liquid filling cavity 2(b) from flowing out from the distal end of the catheter 2).

[0031] In a preferred embodiment of the variable hardness microcatheter of the present invention, the inner tube 21 is made of PTFE; the reinforcing layer 22 is a stainless steel reinforcing layer; and the outer tube 23 is made of PEBAX with different hardnesses, with the hardness of the outer tube 23 gradually decreasing from the proximal end to the distal end.

[0032] In a preferred embodiment of the variable hardness microcatheter of the present invention, a radiopaque ring 4 is further provided at the distal end of the catheter 2.

[0033] In a preferred embodiment of the variable-hardness microcatheter of the present invention, the variable-hardness microcatheter is as follows: Figure 1 As shown, it includes: a three-way handle 1, a catheter 2, a balloon 3, and a contrast-enhancing ring 4. Figure 2 As shown, the three-way handle 1 has a Luer connector 1(a) and a Luer connector 1(b). The catheter 2 includes an instrument delivery chamber 2(a) and a fluid filling chamber 2(b). The catheter 2 is thermally composited from a PTFE inner layer 21, a stainless steel wire reinforcing layer 21, and a PEBAX outer tube 23 of varying hardness. The balloon 3, in its uninflated state, is suspended within the fluid filling chamber 2(b). The proximal ends of the balloon 3 are fixed to the inner walls of the fluid filling chamber 2(b) on both sides (to keep the proximal end of the balloon 3 open, facilitating fluid entry and inflation). The uninflated balloon 3 has no effect on the distal hardness of the catheter 2. Saline solution is introduced through the Luer connector 1(a), and surgical instruments are introduced through the Luer connector 1(b). Figure 3-5 As shown, the balloon 3 is inflated through the Luer connector 1(a) of the three-way handle, and the outer wall of the balloon 3 is in close contact with both sides of the liquid filling chamber 2(b), which increases the rigidity of the distal end of the catheter.

[0034] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A microcatheter with variable stiffness, characterized in that, include: The catheter has an instrument delivery chamber and a fluid filling chamber. The fluid filling chamber is located outside the instrument delivery chamber, and a balloon is disposed within the fluid filling chamber. The instrument delivery chamber is used to deliver an instrument, and the fluid filling chamber is used to deliver fluid into the balloon. The handle is disposed at the proximal end of the catheter and has a first Luer connector and a second Luer connector. The first Luer connector is connected to the fluid filling chamber, and the second Luer connector is connected to the instrument delivery chamber.

2. The variable stiffness microcatheter as described in claim 1, characterized in that, The balloon is positioned at least near the distal end of the catheter.

3. The variable stiffness microcatheter as described in claim 1, characterized in that, The balloon has a proximal opening and a distal sealing. At least the proximal end of the balloon is fixed to the inner wall of the liquid filling cavity.

4. The variable stiffness microcatheter as described in claim 1, characterized in that, There are two liquid filling cavities, which are respectively located on the opposite side of the instrument delivery cavity.

5. The variable stiffness microcatheter as described in claim 1, characterized in that, The catheter is composed of an inner tube, a reinforcing layer, and an outer tube. The instrument delivery chamber is an inner tubular cavity; The liquid filling cavity is disposed on the wall of the outer tube and extends along the axial direction of the conduit, with the distal end of the liquid filling cavity closed.

6. The variable stiffness microcatheter as described in claim 5, characterized in that, The inner tube is made of PTFE; The reinforcing layer is a stainless steel reinforcing layer; The outer tube is made of PEBAX with different hardness, and the hardness of the outer tube gradually decreases from the proximal end to the distal end.

7. The variable stiffness microcatheter as described in claim 1, characterized in that, The distal end of the catheter is also provided with a radiopaque ring.

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