Suction catheter

Abstract

The invention provides an aspiration catheter which comprises a catheter body and a tip portion located at the distal end of the catheter body, the tip portion is provided with at least one expandable assembly, and the expandable assembly is configured to be expandable outwards in the radial direction of the aspiration catheter, so that the cross-sectional area of the tip portion is increased. According to the aspiration catheter, the expandable assembly is arranged at the far end of the aspiration catheter, the expandable assembly can expand outwards in the radial direction to increase the inner diameter of the tip part when thrombus is aspirated, the cross sectional area of the tip part is also increased, and therefore the aspiration force of the aspiration catheter on the thrombus can be effectively increased.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a suction catheter. Background Art

[0002] In order to better treat thrombosis, the prior art provides a suction catheter. During surgery, doctors use the suction catheter to enter the nerve blood vessels and remove the thrombus by applying suction force. These catheters are manufactured using advanced technology and generally include an inner layer, a reinforcement layer that provides support, and an outer sheath that protects the patient from damage by the reinforcement layer.

[0003] One problem with the suction catheter in the prior art is that the suction force is limited by the diameter of the inner lumen of the catheter, and the inner lumen size is constrained by the wall thickness and outer diameter of the catheter. Generally, the wall thickness of the catheter must meet certain thickness requirements to obtain sufficient tensile strength and rupture strength; the outer diameter of the tip of the catheter must be small enough to allow it to be pushed to the distal blood vessel more smoothly, and the wall thickness of the catheter must meet certain thickness requirements to obtain sufficient tensile strength and rupture strength. The tip of the catheter in the prior art usually has a thin wall to maximize the inner lumen diameter, thereby increasing the suction force, while minimizing the outer diameter to reach the distal blood vessel more smoothly, but this technology reduces the wall thickness and cannot guarantee the tensile strength and rupture strength of the catheter. Therefore, the current suction catheter cannot take into account the wall thickness and outer diameter requirements of the catheter tip to meet the catheter's passing performance while ensuring that it has sufficient suction force. Summary of the invention

[0004] In view of the problems in the prior art, the object of the present invention is to provide a suction catheter that effectively increases the suction force while ensuring that the outer diameter and thickness of the distal end of the catheter meet the requirements.

[0005] An embodiment of the present invention provides a suction catheter, which includes a tube body and a tip portion located at the distal end of the tube body, wherein the tip portion is provided with at least one expandable component, and the expandable component is configured to expand radially outward along the suction catheter.

[0006] In some embodiments, the expandable component is annular; and the expandable component is configured such that when the expandable component is expanded radially outward, the axial length of the expandable component decreases.

[0007] In some embodiments, the tip portion further comprises a first outer sheath covering an outer surface of the expandable component.

[0008] In some embodiments, the first outer sheath has a durometer less than or equal to 25D.

[0009] In some embodiments, the tube body includes an inner layer, a reinforcement layer, and a second outer sheath arranged in sequence from the inside to the outside.

[0010] In some embodiments, the second outer sheath and the first outer sheath are integrally formed, or the second outer sheath and the first outer sheath are separately formed and connected.

[0011] In some embodiments, the reinforcement layer includes a first reinforcement layer and a second reinforcement layer, wherein the second reinforcement layer is located outside the first reinforcement layer, at least a portion of the inner layer extends into the tip portion, and at least a portion of the distal end of the second reinforcement layer extends into the proximal end of the expandable component.

[0012] In some embodiments, a surface of the expandable component is formed with a plurality of openings and / or a plurality of grooves distributed along the circumferential direction.

[0013] In some embodiments, the expandable component includes a plurality of struts connected to each other to form an annular structure, and the plurality of openings are formed between the plurality of struts.

[0014] In some embodiments, the material of the expandable component includes stainless steel or nickel-titanium alloy.

[0015] In some embodiments, the material of the expandable component further comprises a radiopaque material, wherein the radiopaque material is a combination of one or more of platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, platinum, tungsten, tantalum, tungsten-tantalum alloy and gold.

[0016] In some embodiments, the tip portion is provided with at least two expandable components arranged along the axial direction; the at least two expandable components are connected to each other or spaced apart.

[0017] The suction catheter provided by the present invention has the following advantages:

[0018] The present invention provides an expandable component at the tip of the suction catheter. When aspirating a thrombus, the expandable component can expand radially outward to increase the inner diameter of the tip, thereby increasing the cross-sectional area of ​​the tip, thereby effectively increasing the suction force of the suction catheter on the thrombus. At the same time, the thickness of the tip can be kept unchanged, thereby maintaining the suction catheter with good tensile strength and rupture resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, objectives and advantages of the present invention will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0020] Figure 1 is a schematic structural diagram of a suction catheter according to an embodiment of the present invention;

[0021] Figure 2 is a perspective view of an expandable structure according to a first embodiment of the present invention;

[0022] Figure 3 is a front view of an expandable structure according to a first embodiment of the present invention;

[0023] Figure 4 is a perspective view of an expandable structure according to a second embodiment of the present invention;

[0024] Figure 5 is a perspective view of an expandable structure according to a third embodiment of the present invention;

[0025] Figure 6 It is a front view of an expandable structure according to a third embodiment of the present invention.

[0026] Reference numerals:

[0027] 10 Tube body 4 Second outer sheath

[0028] 20 Tip 5 Expandable component

[0029] 1 Inner layer 51 Opening

[0030] 2 First reinforcement layer 52 pillars

[0031] 3 Second reinforcement layer 6 First outer sheath DETAILED DESCRIPTION

[0032] The example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments described herein; on the contrary, these embodiments are provided so that the present invention will be comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. "Or" and "or" in the specification may both mean "and" or "or". Although the terms "upper", "lower", "between", etc. may be used in this specification to describe different exemplary features and elements of the present invention, these terms are used herein only for convenience, such as according to the directions of the examples described in the accompanying drawings. Nothing in this specification should be construed as requiring a specific three-dimensional orientation of the structure to fall within the scope of the present invention. Although "first" or "second" etc. are used in this specification to represent certain features, they are only used to represent the function, and are not used as a limitation on the number and importance of specific features. In the present invention, for a component, "distal end" refers to the end away from the operator, and "proximal end" refers to the end close to the operator. For example, in Figure 1 In the perspective of FIG. 1 , the right side of the suction catheter is the distal end, and the left side is the proximal end. The "axial direction" in the present invention refers to the axial direction of the suction catheter, for example, Figure 1In the perspective of the present invention, the left and right directions are the axial direction, and the "radial direction" of the present invention refers to the radial direction of the suction catheter, for example, the diameter direction in a cross section of the suction catheter perpendicular to the axial direction. The inner side and the outer side in the present invention are relative to the axis of the suction catheter, the side close to the axis is the inner side, and the side away from the axis is the outer side.

[0033] The present invention provides a suction catheter, the suction catheter comprises an elongated tube body and a tip portion at the distal end of the tube body, the tip portion is provided with at least one expandable component, the expandable component is configured to expand outward along the radial direction of the suction catheter. Therefore, the expandable component comprises a first state and a second state, the second state being a state of expanding outward relative to the first state. In the initial state, the expandable component is in the first state, and the tip portion has a first cross-sectional area. At this time, the outer diameter of the tip portion is smaller, and it is easier to push into the distal blood vessel, and the pushing performance of the suction catheter will not be affected. When it is necessary to aspirate thrombus, an expansion force along the radial direction of the suction catheter is applied inside the expandable component, so that the expandable component expands outward along the radial direction and enters the second state, and the tip portion has a second cross-sectional area. The second cross-sectional area is larger than the first cross-sectional area, so that the suction force of the suction catheter on the thrombus can be effectively increased, and the thickness of the tip portion can also be ensured to remain unchanged, so as to maintain the suction catheter with good tensile strength and rupture resistance.

[0034] Combine the following Figures 1 to 6 The structure of the suction catheter according to an embodiment of the present invention will be specifically described. It should be understood that the following description is only for illustrative purposes and is not intended to limit the scope of protection of the present invention.

[0035] like Figure 1 As shown, the suction catheter includes an elongated tube body 10 and a tip portion 20 located at the distal end of the tube body 10, and the tip portion 20 is provided with at least one expandable component 5, and the expandable component 5 is configured to expand outward along the radial direction of the suction catheter, thereby increasing the cross-sectional area of ​​the tip portion 20. The cross-sectional area here refers to the cross-sectional area of ​​the opening of the tip portion 20 on a cross section perpendicular to the axial direction of the suction catheter. In some embodiments of the present invention, a flexible first outer sheath 6 is also provided on the outside of the expandable component 5, covering the outer surface of the tip portion 20, and the hardness of the first outer sheath 6 is preferably less than or equal to 25D, and the material of the first outer sheath 6 is preferably thermoplastic polyurethane (TPU) so as not to affect the outward expansion of the expandable component 5. The use of the expandable component 5 as a marking component eliminates the problem in the prior art that the tip of the suction catheter is restricted by a rigid marking component and affects the suction effect.

[0036] The surgical effect of thrombus aspiration using an aspiration catheter is directly related to three capabilities of the aspiration catheter: (1) the ability to reach the thrombus; (2) sufficient aspiration force; and (3) optimal interaction between the thrombus and the aspiration catheter. The ability to reach the thrombus is related to the flexibility, anti-kinking, pushability (the ability to transmit the force used for the push rod to the tip of the aspiration catheter so that it can reach the lesion smoothly), passability (the ability of the aspiration catheter to cross the lesion), and low profile (smaller outer diameter) of the aspiration catheter. The aspiration force of the aspiration catheter is related to the opening cross-sectional area of ​​the tip 20. Under a given applied pressure, a larger opening cross-sectional area can produce a higher aspiration force. The interaction between the thrombus and the aspiration catheter depends on the aspiration force and the ability of the thrombus to be sucked into the lumen of the aspiration catheter.

[0037] In this embodiment, the expandable component 5 includes a first state and a second state, and the second state is a state of outward expansion relative to the first state. In the initial state, the expandable component 5 is in the first state, and the tip portion 20 has a first cross-sectional area. At this time, the outer diameter of the tip portion 20 is smaller, and it is easier to push into the distal blood vessel, and will not affect the pushing performance of the suction catheter, that is, it can have a better ability to reach the thrombus. When it is necessary to aspirate the thrombus, a radial expansion force is applied to the inside of the expandable component 5, so that the expandable component 5 expands radially outward and enters the second state, and the tip portion 20 has a second cross-sectional area. The second cross-sectional area is larger than the first cross-sectional area, which can effectively increase the suction force of the suction catheter on the thrombus.

[0038] The tip 20 of the suction catheter is an important part that affects the suction effect. Since the tip 20 is generally the thinnest part of the suction catheter, its cross-sectional area will affect the suction force applied by the tip 20. The relationship between the suction force and the cross-sectional area of ​​the tip 20 and the applied pressure applied to the tip 20 is as follows:

[0039] Suction force = cross-sectional area of ​​the tip × pressure applied to the tip

[0040] It can be seen that, when the applied pressure to the tip portion 20 remains unchanged, the larger the cross-sectional area of ​​the tip portion 20, the greater the suction force. Therefore, when the tip portion 20 has a larger cross-sectional area, a greater suction force (tip force) can be obtained, and a better integration between the thrombus and the suction catheter can be obtained. The existing tip portion 20 is provided with a rigid marking band, and its inner diameter is a fixed value along the axial direction. It is limited by the inner cavity diameter of the tip portion 20 and cannot obtain a larger suction force. Even if a flexible material is used, it will expand slightly when in contact with an external force, and the degree of expansion is very small, and it will reduce the wall thickness to a certain extent, affecting the pushing performance.

[0041] In the solution of the present invention, in addition to the expansion of the material of the tip 20, further expansion is achieved through the expandable component 5, which is conducive to ensuring that all thrombi are aspirated and no fragments are pushed to the distal end or left in the blood vessel. Therefore, the suction catheter is conducive to obtaining sufficient suction force. In addition, the expandable distal component of the suction catheter allows the suction catheter tip 20 to move more freely relative to the thrombus clot, thereby obtaining the best interaction between the thrombus and the suction catheter.

[0042] like Figure 1 As shown, the tube body 10 includes an inner layer 1, a reinforcement layer and a second outer sheath 4 which are arranged in sequence from the inside to the outside. The inner layer 1 can be made of PTFE (polytetrafluoroethylene), FEP (perfluoroethylene propylene copolymer), TPE (thermoplastic elastomer) and / or PEEK (polyetheretherketone) materials, and the inner surface has a small friction force, which is convenient for the pushing component to pass through. The thickness of the inner layer 1 can be 0.00025 inches-0.001 inches, for example, 0.00075 inches, but the present invention is not limited to this. At least part of the inner layer 1 extends from the tube body 10 to the distal end into the tip 20. The reinforcement layer includes a first reinforcement layer 2 and a second reinforcement layer 3, and the second reinforcement layer 3 is located outside the first reinforcement layer 2. In this embodiment, the first reinforcement layer 2 is a coil layer, which has good flexibility, kink resistance and rupture resistance. The first reinforcement layer 2 can be made of nickel-titanium alloy material or stainless steel material. The thickness of the first reinforcement layer 2 can be 0.0015 inches to 0.004 inches, for example, 0.002 inches. The second reinforcement layer 3 is a braided layer, which has good kink resistance, tensile strength and burst strength. The second reinforcement layer 3 extends from the tube body 10 to at least a portion of the distal end into the tip portion 20, and at least a portion of the distal end of the second reinforcement layer 3 extends into the proximal end of the expandable component 5. The second reinforcement layer 3 is woven with 8 or 16 braided wires, with 60-120 braided nodes per inch, and is made of stainless steel or nickel-titanium alloy. The height of the braided wire is 0.0007 inches to 0.002 inches, for example, 0.001 inches, and the width is 0.001 inches to 0.004 inches, for example, 0.003 inches. The braiding form of each braided node is 1x1, 2x1, 2x2, and these different variations can be freely combined. The second outer sheath 4 is a flexible outer sheath, which can be made of thermoplastic polyurethane material, has good flexibility and burst strength, and its thickness is, for example, 0.003 inches. The hardness of the second outer sheath 4 is also preferably less than or equal to 25D. The second outer sheath 4 and the first outer sheath 6 can be integrally formed. Alternatively, the second outer sheath 4 and the first outer sheath 6 are separately formed and connected. The hardness of the first outer sheath 6 can be less than or equal to the hardness of the second outer sheath 4.

[0043] Figure 2 to Figure 6 The structure of the expandable component 5 of several optional embodiments in this embodiment is shown. In this embodiment, the expandable component 5 is annular. And the surface of the expandable component 5 includes a plurality of openings 51 and / or a plurality of grooves distributed along the circumferential direction, which are cut integrally by laser, so that the expandable component 5 can be self-expanded or can be expanded radially outward when subjected to internal expansion force. When the expandable component 5 expands outward, it deforms as a whole due to its structural characteristics, expands radially and reduces its axial length. For example, an expansion force can be applied to it by arranging an inflatable airbag inside the expandable component 5. In one embodiment, the expandable component 5 can be made of stainless steel or platinum-iridium material. In this case, when the expandable component 5 is expanded by the expansion force inside, it will be permanently deformed, but the degree of deformation will not be so large that the expandable component 5 cannot re-enter the distal vascular system. For example, in one embodiment, the expandable component 5 is made of stainless steel, and when the thrombus is aspirated, the expandable component 5 is expanded by the pressure of the thrombus and permanently deformed, but the degree of deformation will not be so large that the expandable component 5 cannot re-enter the distal vascular system. In another embodiment, the expandable component 5 may be made of a shape memory material, such as a nickel-titanium alloy material, in which case the expandable component 5 is self-expandable. In one embodiment, the expandable component 5 includes a nickel-titanium alloy and a radiopaque material, wherein the radiopaque material is a combination of one or more of a platinum-iridium alloy, a platinum-nickel alloy, a platinum-tungsten alloy, tungsten, tantalum, a tungsten-tantalum alloy, or gold, and the density of the radiopaque material is higher than that of the nickel-titanium alloy material. In this embodiment, the expandable component 5 can improve the suction force of the suction catheter and also realize the imaging function.

[0044] like Figure 2 and Figure 3As shown, it is a schematic diagram of the structure of the expandable component 5 of the first embodiment. The expandable component 5 includes a plurality of pillars 52, which are cross-connected to form an annular structure, and a plurality of openings 51 are formed between the plurality of pillars 52, and the openings 51 can be set to extend in the axial direction. The plurality of pillars 52 form a plurality of units, each unit has an opening 51 in the center, and there is also an opening 51 between two adjacent units. When the expandable component 5 is subjected to an outward expansion force, the opening 51 will expand circumferentially, that is, the circumferential length of the opening 51 increases and the axial length decreases, so that the expandable component 5 expands radially outward. The thickness of the pillar 52 can be selected as needed. When the thickness of the pillar 52 is small, better expansion capacity can be obtained. When the thickness of the pillar 52 is large, relatively higher tensile strength and burst strength can be obtained. Since the main change of this structure when expanding in the radial direction depends on the deformation of the overall structure rather than the thickness change of the pillar 52, therefore, the slight thickness change of the pillar 52 will not have a great influence on the tensile strength and burst strength of the expandable component 5 as a whole.

[0045] like Figure 4 As shown, it is a schematic diagram of the structure of the expandable component 5 of the second embodiment. Among them, the expandable component 5 includes a plurality of pillars 52, and the pillars 52 are connected end to end in sequence to form an annular structure, and a plurality of openings 51 are formed between the pillars 52, and the openings 51 can be set to extend in the axial direction. The expandable component 5 forms a Z-shaped structure, which can be formed by a flexible belt, or formed by connecting a plurality of flexible belts end to end. When the expandable component 5 is subjected to an outward expansion force, the pillars 52 will extend circumferentially, and the openings 51 will expand circumferentially, that is, the circumferential length of the openings 51 increases and the axial length decreases, so that the expandable component 5 expands radially outward. The thickness of the pillars 52 can be selected as needed. Similarly, when this structure expands in the radial direction, the main change depends on the deformation of the overall structure rather than the thickness change of the pillars 52. Therefore, the slight thickness change of the pillars 52 will not affect the overall tensile strength and burst strength of the expandable component 5.

[0046] like Figure 5 and Figure 6 As shown, it is a schematic diagram of the structure of the expandable component 5 of the third embodiment. Among them, the tip portion 20 is provided with three expandable components 5, and the three expandable components 5 are connected to each other. In other embodiments, the number of expandable components 5 of the tip portion 20 can also be at least two, for example, two, four or more, and multiple expandable components 5 are arranged along the axial direction, and at least two of the expandable components 5 are connected to each other or arranged at intervals, all of which belong to the protection scope of the present invention.

[0047] Figure 2 to Figure 6Only several structures of the expandable components 5 are shown exemplarily. In other alternative embodiments, the expandable component 5 may also adopt other structures, for example, the inner surface and / or outer surface of the expandable component 5 is provided with a plurality of grooves, or a combination of grooves and openings, and the struts 52 may be combined in other forms, such as spiral winding, multiple spirals arranged side by side, etc. The direction of the opening may also be axial / circumferential opening, etc.

[0048] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A suction catheter, characterized in that: The suction catheter comprises a tube body and a tip portion located at a distal end of the tube body, wherein the tip portion is provided with at least one expandable component, and the expandable component is configured to be expandable outwardly along the radial direction of the suction catheter.

2. The suction catheter according to claim 1, characterized in that The expandable component is annular in shape; the expandable component is configured such that when the expandable component expands radially outward, the axial length of the expandable component decreases.

3. The suction catheter according to claim 1, characterized in that The tip portion also includes a first outer sheath covering an outer surface of the expandable component.

4. The suction catheter according to claim 3, characterized in that The hardness of the first outer sheath is less than or equal to 25D.

5. The suction catheter according to claim 3, characterized in that: The pipe body comprises an inner layer, a reinforcement layer and a second outer sheath which are arranged in sequence from the inside to the outside.

6. The suction catheter according to claim 5, characterized in that The second outer sheath and the first outer sheath are integrally formed, or the second outer sheath and the first outer sheath are separately formed and connected.

7. The suction catheter according to claim 5, characterized in that The reinforcement layer includes a first reinforcement layer and a second reinforcement layer, the second reinforcement layer is located outside the first reinforcement layer, at least a portion of the inner layer extends into the tip portion, and at least a portion of the distal end of the second reinforcement layer extends into the proximal end of the expandable component.

8. The suction catheter according to claim 1, characterized in that The surface of the expandable component is formed with a plurality of openings and / or a plurality of grooves distributed along the circumferential direction.

9. The suction catheter according to claim 8, characterized in that The expandable component includes a plurality of struts, the plurality of struts are connected to each other to form an annular structure, and the plurality of openings are formed between the plurality of struts.

10. The suction catheter according to claim 9, characterized in that The material of the expandable component includes stainless steel or nickel-titanium alloy.

11. The suction catheter according to claim 1, characterized in that The material of the expandable component also includes a radiopaque material, and the radiopaque material is a combination of one or more of platinum-iridium alloy, platinum-nickel alloy, platinum-tungsten alloy, platinum, tungsten, tantalum, tungsten-tantalum alloy and gold.

12. The suction catheter according to claim 1, characterized in that The tip portion is provided with at least two expandable components arranged along the axial direction; the at least two expandable components are connected to each other or arranged at intervals.

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