Extension catheter

Abstract

This application relates to an extension catheter. The extension catheter includes: a tube body having a main section and an expandable section connected to the distal end of the main section; the expandable section has elastic deformation capability and a folded portion; the lumen of the tube body allows a balloon to be inserted, the balloon being able to extend into the expandable section; when the balloon located within the expandable section inflates, the folded portion extends, increasing the inner and outer diameters of the expandable section; when the balloon deflates, the folded portion retracts and deforms under the elastic force of the expandable section, allowing the inner and outer diameters of the expandable section to shrink and return to their original size. The extension catheter provided by this application simultaneously possesses excellent deep insertion capability and facilitates the capture of retrograde guidewires or microcatheters.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to an extension catheter. Background Technology

[0002] Percutaneous coronary intervention (PCI) is a treatment method that uses cardiac catheterization to open narrowed or even blocked coronary arteries, thereby improving myocardial blood flow perfusion.

[0003] Reverse CART, short for Reverse Controlled Antegrade Retrograde Subintimal Tracking, is a commonly used technique in interventional treatment of chronic total occlusion (CTO) of the coronary arteries. The main principle of reverse CART is to dilate the CTO lesion by advancing a guidewire and balloon in the forward direction, creating an enlarged true or false lumen. Then, the reverse guidewire is manipulated through the channel created by the forward balloon to ultimately enter the true lumen of the vessel proximal to the CTO. This technique is particularly suitable for complex reverse CTO interventions, such as long lesions, calcified lesions, and tortuous vessel lesions, and is highly valuable for opening reverse CTOs.

[0004] Retrograde guidewire technique is an important method in CTO interventional treatment. This technique primarily utilizes collateral circulation between coronary arteries. A guidewire is inserted from a coronary artery that sends collateral circulation to the occluded vessel, and then guided along the collateral circulation into the occluded vessel, recanalizing the CTO lesion from its distal end. This technique is suitable for patients where antegrade guidewire techniques have failed or where there is no obvious residual tissue at the occlusion site. While it is technically challenging and carries high surgical risks, it boasts a high success rate and can significantly improve the patency rate of CTO lesions.

[0005] Active Greeting Technique (AGT) is a technique that combines deep insertion of a mother-and-child catheter with retrograde CART or retrograde guidewire technology, facilitating guidewire externalization. For details on AGT, please refer to the paper "Activegreeting technique: a mother-and-child catheter based technique to facilitate retrograde wire externalization in recanalization of coronary chronic totalocclusion," Science Bulletin, Volume 63, Issue 23, 2018, Pages 1565-1569, ISSN 2095-9273.

[0006] In related technologies, the AGT technique, when assisting in the externalization of CTO-PCI retrograde interventional treatment, requires an extension catheter with excellent deep insertion capability and the ability to stably accommodate swaying retrograde guidewires or microcatheters. However, excellent deep insertion capability requires the extension catheter to have a small outer diameter to achieve good passage and avoid vascular injury, while efficiently accommodating the retrograde guidewire or microcatheter (i.e., the contralateral guidewire or microcatheter entering the extension catheter) requires the extension catheter to have a large inner diameter lumen to facilitate capture of the retrograde guidewire or microcatheter. Clearly, the extension catheters in related technologies cannot simultaneously meet the requirements of a small outer diameter and a large inner diameter lumen, thus failing to guarantee both excellent deep insertion capability and efficient capture of the retrograde guidewire or microcatheter.

[0007] Therefore, how to make the extension catheter have both excellent deep insertion capability and the small outer diameter and large inner diameter lumen required for efficient capture of the reverse guidewire or microcatheter is a problem that urgently needs to be solved in this field. Summary of the Invention

[0008] To address or partially address the problems existing in the related technologies, this application provides an extension catheter that simultaneously possesses excellent deep insertion capability and facilitates the capture of retrograde guidewires or microcatheters.

[0009] This application provides an extension catheter, comprising: a tube body having a tube body segment and an expandable segment connected to the distal end of the tube body segment, the expandable segment having elastic deformation capability and a folding portion;

[0010] The lumen of the tube body allows a balloon to be inserted, and the balloon can be inserted into the expandable section. When the balloon located in the expandable section inflates, it can extend the folded portion and increase the inner and outer diameters of the expandable section. When the balloon deflates, the folded portion can retract and deform under the elastic force of the expandable section, so that the inner and outer diameters of the expandable section can shrink and recover.

[0011] Furthermore, the expandable section includes a first tube layer and a second tube layer, the first tube layer is connected to the second tube layer, the innermost layer of the expandable section is the second tube layer, and the second tube layer forms the lumen of the expandable section;

[0012] The first tubular layer includes a plurality of circumferentially arranged lobes, the proximal ends of which are connected to the tubular body segment, and the second tubular layer is folded to form the folded portion.

[0013] Furthermore, the first tube layer has two layers, namely an inner first tube layer and an outer first tube layer, wherein the outer first tube layer is sleeved on the inner first tube layer, and there is a gap between the outer first tube layer and the inner first tube layer;

[0014] The second tube layer is fixedly connected to the inner surface of the inner first tube layer and the inner surface of the outer first tube layer, respectively. There is a gap between the flap of the inner first tube layer and the flap of the outer first tube layer to accommodate the folded portion. The second tube layer is stacked in the radial direction of the expandable section within the gap between the flap of the inner first tube layer and the flap of the outer first tube layer to form the folded portion.

[0015] Furthermore, the folded portion has two layers of the second tubular layer.

[0016] Furthermore, the expandable section is provided with the second tube layer, the inner first tube layer, the second tube layer, the second tube layer and the outer first tube layer in sequence from the inside to the outside.

[0017] Furthermore, the first tube layer is sleeved on the second tube layer, the second tube layer is fixedly connected to the inner surface of each of the valve bodies, and the folded portion and the valve body are arranged opposite each other in the radial direction of the expandable section;

[0018] The second tubular layer is stacked along the radial direction of the expandable section to form the fold.

[0019] Furthermore, the folded portion has at least three layers of the second tubular layer.

[0020] Furthermore, each of the aforementioned valve bodies is provided with the folded portion; and / or

[0021] The plurality of folded portions are evenly arrayed along the circumference of the expandable segment.

[0022] Furthermore, the first tube layer is sleeved on the second tube layer, the second tube layer includes the folded portion and the folded area, and the flap is disposed on the outer surface of the folded area;

[0023] The second tubular layer is stacked along the circumferential direction of the expandable section to form the fold.

[0024] Furthermore, the folded portion has multiple folded portions, which are spaced apart circumferentially along the expandable segment, and the folded area is located between two adjacent folded portions.

[0025] Furthermore, the tube body section includes an inner layer, an intermediate layer sleeved on the inner layer, and an outer layer sleeved on the intermediate layer, wherein the intermediate layer is a braided layer or a spring layer;

[0026] The first tube layer and the outer layer are integrally formed, and the second tube layer and the inner layer are integrally formed.

[0027] Furthermore, the first tubular layer is made of polyether block polyamide Pebax or nylon PA material; and / or

[0028] The second tube layer is made of polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE).

[0029] Furthermore, a first developing element is provided at the distal end of the expandable segment.

[0030] Furthermore, a second developing element is provided at the distal end of the tube body segment, and a third developing element is provided at the proximal end of the tube body segment.

[0031] Furthermore, the aforementioned extension catheter also includes a rod and a socket, wherein the distal end of the rod is connected to the proximal end of the tube body, and the proximal end of the rod is connected to the socket.

[0032] Furthermore, the outer diameter of the expandable section varies from 1mm to 3mm.

[0033] The technical solution provided in this application can include the following beneficial effects: By setting an expandable segment with elastic deformation capability at the distal end of the catheter body, the folded portion does not extend when the expandable segment is not expanded, and the inner and outer diameters of the expandable segment are small, thereby obtaining good passage and facilitating deep insertion to the vicinity of the CTO lesion location while avoiding vascular damage; when receiving a retrograde guidewire or microcatheter, the expandable segment expands using the inserted balloon, causing it to elastically deform as the balloon expands outward, and the folded portion extends accordingly, increasing the inner and outer diameters of the expandable segment, thereby facilitating the insertion of the retrograde guidewire or microcatheter into the expandable segment. Therefore, the extended catheter of the above solution can simultaneously possess excellent deep insertion capability and facilitate the capture of retrograde guidewires or microcatheters.

[0034] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0035] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0036] Figure 1 This is a schematic diagram of the structure of an extension catheter shown in an embodiment of this application;

[0037] Figure 2 yes Figure 1 The cross-sectional view of the tube body of the extended conduit shown;

[0038] Figure 3 yes Figure 1 A cross-sectional view of the expandable section of the extension catheter shown;

[0039] Figure 4 This is a cross-sectional view of another expandable segment of an extension catheter shown in an embodiment of this application;

[0040] Figure 5 This is a cross-sectional view of another expandable segment of an extension catheter shown in an embodiment of this application;

[0041] Figure 6 This is a schematic diagram illustrating the working principle of the extension catheter shown in the embodiments of this application, wherein the balloon is in an inflated state;

[0042] Figure 7 This is a schematic diagram illustrating the working principle of the extension catheter shown in the embodiments of this application, wherein the balloon is in a reduced state and the expandable section slowly retracts from the expanded state;

[0043] Figure 8 This is a schematic diagram illustrating the working principle of an extension catheter as shown in an embodiment of this application, wherein a reverse guidewire or microcatheter extends into the catheter body.

[0044] Figure label:

[0045] 1-tube body,

[0046] 11-Pipe body, 111-Inner layer, 112-Middle layer, 113-Outer layer

[0047] 12-Expandable segment, 121-First tubular layer, 1211-Valve body,

[0048] 121a - Inner first tubular layer, 1211a - Valve body,

[0049] 121b - outer first tubular layer, 1211b - valve body,

[0050] 122 - Second tube layer, 122a - Folded section, 122b - Unfolded area

[0051] 13-First developing element, 14-Second developing element, 15-Third developing element, 16-Lumen,

[0052] 2-rod,

[0053] 3-tube seat,

[0054] 4-Balloon,

[0055] 5-Reverse guidewire or microcatheter. Detailed Implementation

[0056] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0057] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0058] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0059] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0060] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0061] Figure 1 This is a schematic diagram of the structure of an extension catheter provided in an embodiment of this application. Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the tube body 1 of the extended conduit. Figure 3 yes Figure 1 A cross-sectional view of the expandable section 12 of the extended catheter shown.

[0062] like Figures 1 to 3 As shown, this application provides an extension catheter, including a tube body 1, the tube body 1 having a tube body section 11 and an expandable section 12 connected to the distal end of the tube body section 11, the expandable section 12 having elastic deformation capability, and the expandable section 12 having a folded portion 122a.

[0063] It should be noted that in the embodiments of this application, "distal" and "proximal" are defined according to the distance from the operator (e.g., a doctor) or the external operating device (e.g., an interventional robot) outside the patient along the axial direction of the extension catheter. The end closer to the operator or operating device is the proximal end, and the end farther from the operator or operating device is the distal end. Specifically, as shown... Figure 1 As shown, in the embodiments of this application, the distal end of each component of the extension catheter refers to its left end in the figure, and the proximal end of each component of the extension catheter refers to its right end in the figure.

[0064] The elastic deformation capability of the expandable section 12 allows it to shrink and recover after radial expansion. The lumen 16 of the tube body 1 allows a balloon to extend into the expandable section 12. When the balloon inflates within the expandable section 12, the fold 122a extends, increasing the inner and outer diameters of the expandable section 12. When the balloon deflates, the fold 122a retracts under the elastic force of the expandable section 12, allowing its inner and outer diameters to shrink and recover. The balloon can be a product already available in the art, and its expansion and contraction are controlled by inflating and inhaling air. The lumen 16 of the tube body 1 extends through the tube body 1, and the balloon can extend into the lumen 16 from the proximal end of the tube body 1 and into the expandable section 12.

[0065] By providing an expandable segment 12 with elastic deformation capability at the distal end of the catheter body 11, the fold 122a remains closed when the expandable segment 12 is not expanded. The smaller inner and outer diameters of the expandable segment 12 provide good passage, avoid vascular injury, and facilitate deep insertion. When a guidewire or microcatheter is encountered, the balloon within the expandable segment 12 inflates, causing elastic deformation of the expandable segment 12. As the expandable segment 12 expands, the fold 122a extends accordingly, increasing the inner and outer diameters of the expandable segment 12, facilitating the insertion of the guidewire or microcatheter into the expandable segment 12. Therefore, the extended catheter described above exhibits excellent deep insertion capability and facilitates the capture of guidewires or microcatheters.

[0066] In some embodiments, the expandable segment 12 includes a first tubular layer 121 and a second tubular layer 122, the first tubular layer 121 and the second tubular layer 122 are connected, the innermost layer 111 of the expandable segment 12 is the second tubular layer 122, and the second tubular layer 122 forms the lumen of the expandable segment 12. The first tubular layer includes a plurality of circumferentially arranged valves, the proximal ends of the valves are connected to the tubular body segment 11, and the second tubular layer 122 is folded to form a folded portion 122a.

[0067] When the expandable segment 12 expands, the fold 122a extends, and multiple valves expand outwards like flower petals, increasing the inner and outer diameters of the expandable segment 12. The second tubular layer 122 may have a certain degree of flexibility to ensure that related instruments can safely pass through the lumen of the expandable segment 12; the second tubular layer 122 may also have a certain degree of elasticity, allowing the fold 122a to retract back to its unexpanded state when the external force of balloon expansion is removed, and the second tubular layer 122 as a whole may be a continuous ring shape. The first tubular layer may have stronger elasticity relative to the second tubular layer 122, and multiple valves will move closer together under the elastic action when the expandable segment 12 contracts, exerting an inward contraction force on the second tubular layer 122, further driving the fold 122a to fold back. The contraction and deformation of the expandable segment 12 may proceed slowly; for example, when the balloon shrinks, the expandable segment 12 slowly retracts from its expanded state. During this process, a retrograde guidewire or microcatheter may be inserted into the expandable segment 12.

[0068] like Figure 3 As shown, in some embodiments, the first tubular layer has two layers: an inner first tubular layer 121a and an outer first tubular layer 121b. The outer first tubular layer 121b is sleeved on the inner first tubular layer 121a, and there is a gap between the outer first tubular layer 121b and the inner first tubular layer 121a. The inner first tubular layer 121a has three spaced-apart valves 1211a, and the outer first tubular layer 121b has three spaced-apart valves 1211b.

[0069] The second tubular layer 122 is fixedly connected to the inner surface of the inner first tubular layer 121a and the inner surface of the outer first tubular layer 121b, respectively. A gap exists between the valve body 1211a of the inner first tubular layer 121a and the valve body 1211b of the outer first tubular layer 121b to accommodate the folded portion 122a. The second tubular layer 122 is stacked along the radial direction of the expandable section 12 within the gap between the valve body 1211a of the inner first tubular layer 121a and the valve body 1211b of the outer first tubular layer 121b, thereby forming the folded portion 122a. The folded portion 122a is located within the gap between the outer surface of the valve body 1211a and the inner surface of the valve body 1211b.

[0070] Specifically, the valve bodies 1211a and 1211b are not aligned radially in the expandable section 12. The two ends of the valve body 1211a correspond to the middle of two adjacent valve bodies 1211b, and the two ends of the valve body 1211b also correspond to the middle of two adjacent valve bodies 1211a. The second tube layer 122 extends along the inner surface of the valve body 1211a and is fixedly connected to the inner surface of the valve body 1211a. Then, the second tube layer 122 extends from the end of the valve body 1211a to the outer surface of the valve body 1211a, and extends along the outer surface of the valve body 1211a to the part corresponding to the end of the valve body 1211b. Finally, the second tube layer 122 extends outward to the end of the valve body 1211b, and extends back along the inner surface of the valve body 1211b, thereby forming two folded second tube layers 122, i.e., folded portions 122a, between the outer surface of the valve body 1211a and the inner surface of the valve body 1211b.

[0071] The second tubular layer 122 on the inner surface of the valve body 1211a is fixedly connected to the valve body 1211a, the second tubular layer 122 on the inner surface of the valve body 1211b is fixedly connected to the valve body 1211b, and the second tubular layer 122 on the outer surface of the valve body 1211a is not fixedly connected to the valve body 1211a. That is, when the expandable section 12 expands or contracts, the second tubular layer 122 on the outer surface of the valve body 1211a can move relative to the valve body 1211a, thereby causing the folded portion 122a to extend or contract.

[0072] The second tube layer 122 and the inner surface of the valve body 1211a, as well as the second tube layer 122 and the inner surface of the valve body 1211b, can be integrally formed by welding or fusion. The connection surface between them is represented by dashed lines in the figure, but this connection surface may not exist in the actual cross-sectional view.

[0073] Figure 3 The folded portion 122a in the illustrated embodiment has two layers of second tubes 122. In some other embodiments, the folded portion 122a may have more layers of second tubes 122, such as three layers of second tubes 122.

[0074] In some embodiments, such as Figure 3 As shown, the expandable section 12 is provided with a second tube layer 122, an inner first tube layer 121a, a second tube layer 122, a second tube layer 122 and an outer first tube layer 121b from the inside to the outside, that is, the expandable section 12 has a five-layer structure, of which the second tube layer 122 has three layers and the first tube layer has two layers.

[0075] Figure 4 This is a cross-sectional view of another expandable section 12 of an extension catheter shown in an embodiment of this application. The expandable section 12 also includes a first tubular layer 121 and a second tubular layer 122.

[0076] like Figure 4 As shown, in some embodiments, with Figure 3 The difference in the illustrated embodiment is that the first tube layer 121 is sleeved on the second tube layer 122, the second tube layer 122 is fixedly connected to the inner surface of each valve body 1211, and the folded portion 122a is arranged opposite to the valve body 1211 in the radial direction of the expandable section 12. The second tube layer 122 is stacked along the radial direction of the expandable section 12 to form the folded portion 122a.

[0077] Specifically, Figure 4 The embodiment shown has a first tube layer 121 and a second tube layer 122. The first tube layer 121 has three sets of circumferentially arranged valves 1211. Each set has three circumferentially arranged valves 1211, and each set has one larger valve 1211 and two smaller valves 1211. The inner surface of each valve 1211 has a fold 122a. A second tube layer 122 is also provided on part of the inner surface of the larger valve 1211 and connected to the fold 122a.

[0078] In some embodiments, such as Figure 4 As shown, the folded portion 122a has three layers of second tubular layers 122. When the expandable section 12 deforms, the three layers of second tubular layers 122 of the folded portion 122a undergo relative displacement, causing the folded portion 122a to extend or retract. The folded portion 122a may also have more than three layers of second tubular layers 122, for example, six layers of second tubular layers 122.

[0079] In some embodiments, such as Figure 4 As shown, each valve body 1211 has a folded portion 122a on its inner surface. In some embodiments, the plurality of folded portions 122a are uniformly arrayed along the circumference of the expandable section 12, for example... Figure 4 In the middle, every three folds 122a are arranged in a circumferential array.

[0080] Figure 5 This is a cross-sectional view of another expandable section 12 of an extension catheter shown in an embodiment of this application. The expandable section 12 also includes a first tubular layer 121 and a second tubular layer 122.

[0081] like Figure 5 As shown, in some embodiments, with Figure 3 The difference in the illustrated embodiment is that the first tube layer 121 is sleeved on the second tube layer 122, the second tube layer 122 includes a folded portion 122a and an folded region 122b, and the flap 1211 is disposed on the outer surface of the folded region 122b. The second tube layer 122 is stacked along the circumferential direction of the expandable section 12 to form the folded portion 122a.

[0082] Specifically, the valve body 1211 can be fixedly connected to the outer surface of the folded region 122b, for example, by welding or fusion. The valve body 1211 and the folded region 122b are arranged opposite each other in the radial direction of the expandable section 12, but not opposite to the folded portion 122a in the radial direction. The second tube layer 122 has three folded regions 122b and three folded portions 122a, which are arranged alternately. The valve body 1211 also has three valve bodies, each corresponding to one of the three folded regions 122b. The folded portion 122a is formed by stacking the second tube layer 122 along the circumferential direction of the expandable section 12. The second tube layer 122 is wavy or serpentine in the folded portion 122a, and can expand and contract when the expandable section 12 deforms. This embodiment is relative to Figure 3 and Figure 4 The expandable segment 12 in the illustrated embodiment is more flexible.

[0083] In some embodiments, the folded portions 122a are multiple, and the multiple folded portions 122a are arranged at circumferential intervals along the expandable segment 12. The folded area 122b is located between two adjacent folded portions 122a, for example... Figure 5 As shown, it has three folded portions 122a and three folded areas 122b. Of course, the number of folded portions 122a and folded areas 122b can also be other, such as two, four, etc.

[0084] In some embodiments, such as Figure 1 and Figure 2 As shown, the tube body 11 includes an inner layer 111, an intermediate layer 112 sleeved on the inner layer 111, and an outer layer 113 sleeved on the intermediate layer 112. The intermediate layer 112 is a braided layer or a spring layer. The first tube layer and the outer layer 113 are integrally formed, and the second tube layer 122 and the inner layer 111 are integrally formed. The first tube layer and the outer layer 113 are a continuous whole. The outer layer 113 can have different hardnesses from the proximal end to the distal end as needed to facilitate pushing and deformation. The second tube layer 122 and the inner layer 111 are a continuous whole. The folded portion 122a of the second tube layer 122 can be formed using folding and pressing technology in the art.

[0085] In some embodiments, the first tube layer 121 is made of polyether block polyamide Pebax or nylon PA material. Of course, the first tube layer can also be made of other highly compliant polymer materials.

[0086] In some embodiments, the second tube layer 122 is made of polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE). Of course, the second tube layer 122 can also be made of other suitable materials.

[0087] In some embodiments, a first imaging element 13 is provided at the distal end of the expandable segment 12. The first imaging element 13 is used to mark the position of the distal end of the expandable segment 12, which can be observed by the surgeon in conjunction with imaging equipment, facilitating the operation. The first imaging element 13 can be metal or a metal composite material. When the first imaging element 13 is made of metal, it can be a sheet-like structure with a certain elastic deformation capability and sandwiched between the first tube layer and the second tube layer 122. When the first imaging element 13 is made of metal composite material, it can be connected to the first tube layer or the second tube layer 122 or be an integral structure. The first imaging element 13 may contain radiopaque imaging substances, such as bismuth, tungsten powder, etc.

[0088] In some embodiments, such as Figure 1 and Figure 2 As shown, a second imaging element 14 is provided at the distal end of the tube body 11, and a third imaging element 15 is provided at the proximal end of the tube body 11. The second imaging element 14 and the third imaging element 15 are used to mark the corresponding positions of the tube body 11, so that they can be observed by the surgeon in conjunction with the imaging equipment, which is beneficial to the operation. The second imaging element 14 and the third imaging element 15 can be imaging rings, and the material and structure of the second imaging element 14 and the third imaging element 15 can be similar to the first imaging element 13.

[0089] In some embodiments, such as Figure 1 As shown, the extension catheter also includes a rod 2 and a tube seat 3. The distal end of the rod 2 is connected to the proximal end of the tube body 11, and the proximal end of the rod 2 is connected to the tube seat 3. The tube seat 3 is located outside the body, and the rod 2 serves to push the tube body 1. The rod 2 can be made of metal. Both the intermediate layer 112 and the rod 2 can be made of high-elasticity metal materials such as austenitic stainless steel, titanium alloy, or nickel-titanium alloy.

[0090] In some embodiments, the outer diameter of the expandable segment 12 varies from 1 mm to 3 mm. Specifically, in actual use, the outer diameter of the expandable segment 12 after expansion can be determined according to the actual situation. For example, the outer diameter of the expandable segment 12 can be expanded from 1 mm to 2 mm, instead of expanding to the maximum range of 3 mm.

[0091] Figure 6 This is a schematic diagram illustrating the working principle of the extension catheter shown in the embodiments of this application, wherein the balloon 4 is in an inflated state; Figure 7This is a schematic diagram of the working principle of the extension catheter shown in the embodiment of this application, wherein the balloon 4 is in a reduced state and the expandable section 12 slowly retracts from the expanded state; Figure 8 This is a schematic diagram of the working principle of the extension catheter shown in the embodiment of this application, wherein the reverse guidewire or microcatheter 5 is inserted into the tube body 1, and the expandable section 12 is restored to the unexpanded state.

[0092] In this embodiment of the application, when the extension catheter is in operation, the catheter body 1 is pushed to the vicinity of the CTO lesion with the expandable section 12 in the undilated state. The inner and outer diameters of the expandable section 12 are small, providing good passage and facilitating deep insertion while avoiding vascular damage. Figure 6 As shown, when the expandable segment 12 is deeply inserted to the corresponding position to meet the reverse guidewire or microcatheter 5, the balloon 4 is inflated. The inflated balloon 4 causes the expandable segment 12 to expand, and the fold 122a extends accordingly when the expandable segment 12 expands, increasing the inner and outer diameters of the expandable segment 12. Figure 7 As shown, when the balloon 4 is reduced in size, the rate of deformation of the expandable section 12 is delayed relative to the balloon 4, and the expandable section 12 remains in an expanded state. Figure 8 As shown, the balloon 4 is withdrawn, and the reverse guidewire or microcatheter 5 is inserted into the tube body 1 from the expandable section 12 to complete the operation of actively receiving the reverse guidewire or microcatheter 5.

[0093] In summary, the extension catheter provided in this application embodiment can be deeply inserted into the distal coronary artery and is dilatant. The distal dilatant segment 12 is dilated using the external force of a balloon, solving the compatibility problem between the small deep insertion outer diameter and the large receiving lumen required for CTO-AGT (Active Guest-Greeting Technique) in percutaneous coronary intervention (PCI) procedures. This facilitates the smooth externalization of retrograde CART or retrograde guidewire techniques. The wall of the dilatant segment 12 conforms to the blood vessel after dilation, preventing vascular damage or perforation and blood loss due to surgical abnormalities. The size of the dilatant segment 12 of the catheter body 1 can be adjusted according to the patient's actual vascular condition, eliminating the need for catheter replacement and reducing surgical time. Contrast markers are added to the proximal portion of the catheter body 1 for easy and precise positioning of the instrument delivery inlet. The extension catheter has a smaller pre-dilation outer diameter and can be independently advanced, eliminating the need for a guiding catheter during deep insertion and avoiding vascular damage caused by a large outer diameter. The expandable segment 12 expands to the required size, allowing the tube wall to better conform to the blood vessel and avoid unnecessary hematoma. After the expandable segment 12 recovers its elasticity, it has a smaller inner diameter of the tube body 1, which can further assist the contralateral microcatheter in entering the guidewire and successfully complete the externalization. The contrast-enhancing elements near both ends of the tube body 1 facilitate the determination of the catheter port location.

[0094] The solution of this application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. Those skilled in the art should also understand that the actions and modules involved in the specification are not necessarily essential to this application. Furthermore, it is understood that the steps in the method of this application embodiment can be adjusted, combined, and deleted according to actual needs, and the modules in the device of this application embodiment can be combined, divided, and deleted according to actual needs.

[0095] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An extension catheter, characterized in that, include: A tube body having a tube body section and an expandable section connected to the distal end of the tube body section, the expandable section having elastic deformation capability and a folding portion; The lumen of the tube body allows a balloon to be inserted, and the balloon can be inserted into the expandable section. When the balloon located in the expandable section inflates, it can extend the folded portion and increase the inner and outer diameters of the expandable section. When the balloon deflates, the folded portion can retract and deform under the elastic force of the expandable section, so that the inner and outer diameters of the expandable section can shrink and recover.

2. The extension catheter according to claim 1, characterized in that: The expandable section includes a first tube layer and a second tube layer, the first tube layer is connected to the second tube layer, the innermost layer of the expandable section is the second tube layer, and the second tube layer forms the cavity of the expandable section; The first tubular layer includes a plurality of circumferentially arranged lobes, the proximal ends of which are connected to the tubular body segment, and the second tubular layer is folded to form the folded portion.

3. The extension catheter according to claim 2, characterized in that: The first tube layer has two layers, namely an inner first tube layer and an outer first tube layer, wherein the outer first tube layer is sleeved on the inner first tube layer and there is a gap between the outer first tube layer and the inner first tube layer; The second tube layer is fixedly connected to the inner surface of the inner first tube layer and the inner surface of the outer first tube layer, respectively. There is a gap between the flap of the inner first tube layer and the flap of the outer first tube layer to accommodate the folded portion. The second tube layer is stacked in the radial direction of the expandable section within the gap between the flap of the inner first tube layer and the flap of the outer first tube layer to form the folded portion.

4. The extension catheter according to claim 3, characterized in that: The folded portion has two layers of the second tube.

5. The extension catheter according to claim 3, characterized in that: The expandable section is provided with the second tube layer, the inner first tube layer, the second tube layer, and the outer first tube layer in sequence from the inside to the outside.

6. The extension catheter according to claim 2, characterized in that: The first tube layer is sleeved on the second tube layer, the second tube layer is fixedly connected to the inner surface of each of the valve bodies, and the folded portion and the valve body are arranged opposite each other in the radial direction of the expandable section; The second tubular layer is stacked along the radial direction of the expandable section to form the fold.

7. The extension catheter according to claim 6, characterized in that: The folded portion has at least three layers of the second tube.

8. The extension catheter according to claim 6, characterized in that: Each of the aforementioned valve bodies is provided with the folded portion; and / or The plurality of folded portions are evenly arrayed along the circumference of the expandable segment.

9. The extension catheter according to claim 2, characterized in that: The first tube layer is sleeved on the second tube layer, the second tube layer includes the folded portion and the folded region, and the petal is disposed on the outer surface of the folded region; The second tubular layer is stacked along the circumferential direction of the expandable section to form the fold.

10. The extension catheter according to claim 9, characterized in that: The folded portion has multiple folded portions, which are spaced apart circumferentially along the expandable segment, and the folded area is located between two adjacent folded portions.

11. The extension catheter according to claim 2, characterized in that: The tube section includes an inner layer, an intermediate layer sleeved on the inner layer, and an outer layer sleeved on the intermediate layer, wherein the intermediate layer is a braided layer or a spring layer; The first tube layer and the outer layer are integrally formed, and the second tube layer and the inner layer are integrally formed.

12. The extension catheter according to claim 2, characterized in that: The first tube layer is made of polyether block polyamide Pebax or nylon PA material; and / or The second tube layer is made of polytetrafluoroethylene (PTFE) or high-density polyethylene (HDPE).

13. The extension catheter according to claim 2, characterized in that: The distal end of the expandable section is provided with a first developing element.

14. The extension catheter according to claim 1, characterized in that: The distal end of the tube section is provided with a second developing element, and the proximal end of the tube section is provided with a third developing element.

15. The extension catheter according to claim 1, characterized in that: It also includes a rod and a tube seat, wherein the distal end of the rod is connected to the proximal end of the tube section, and the proximal end of the rod is connected to the tube seat.

16. The extension catheter according to claim 1, characterized in that: The outer diameter of the expandable section varies from 1mm to 3mm.

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