Sheath tube, catheter sheath and delivery system

Abstract

The utility model relates to a sheathing canal, a catheter sheath and a conveying system.The sheathing canal comprises an expandable section, the expandable section comprises a first wall thickness part and a second wall thickness part which are connected in the circumferential direction, the thickness of the first wall thickness part is smaller than that of the second wall thickness part, and the first wall thickness part can be folded inwards or outwards; the expandable section can be extruded to expand outwards in the radial direction and can be folded and contracted when the radial extrusion acting force is relieved. According to the sheathing canal, the catheter sheath and the conveying system, the sheathing canal is provided with the expandable section, the peripheral diameter is changed through expansion and retraction of the expandable section, and therefore the application range of the sheathing canal for establishing conveying channels in different blood vessels is enlarged, and meanwhile vascular complications caused by expanding the blood vessels for a long time can be avoided.

Description

Technical Field

[0001] This application relates to the technical field of medical devices, and particularly to a sheath tube, a catheter sheath, and a delivery system. Background Art

[0002] With the development trend of an aging society in China, the incidence of senile valvular degenerative diseases is increasing continuously. For such patients, surgical replacement was once the only treatment method to extend life. However, elderly patients are often contraindicated for surgery due to advanced age, weak constitution, severe lesions, or combined with other diseases. As an effective treatment method, the transcatheter valve implantation of interventional therapy does not require the patient to undergo a high-risk thoracotomy process. This technology uses a delivery system to send an interventional catheter through the femoral artery and deliver an artificial heart valve to the target valve area to open, thereby completing the implantation of the artificial valve and restoring the valve function. The surgery does not require thoracotomy, so the trauma is small and the postoperative recovery is fast. During this interventional treatment process, it is necessary to puncture through the femoral artery or vein, and then place a catheter sheath to protect the inferior vena cava and establish a delivery channel.

[0003] In the prior art, the commonly used catheter sheath generally uses a sheath tube with a fixed outer diameter, which has a narrow applicable range and is difficult to cover the blood vessels of all patients and the situation where the blood vessels have calcifications. Moreover, the sheath tube needs to be continuously involved in the whole process of the operation, and dilating the blood vessels for a long time will cause more vascular complications. Summary of the Utility Model

[0004] Based on this, a sheath tube, a catheter sheath, and a delivery system are provided to solve the problems that the sheath tube has a narrow applicable range and is prone to cause vascular complications.

[0005] This application provides a sheath tube, which includes an expandable section. The circumferential direction of the expandable section includes a first wall thickness portion and a second wall thickness portion connected to each other. The thickness of the first wall thickness portion is less than that of the second wall thickness portion, and the first wall thickness portion can be folded inward or outward, so that the expandable section can be radially expanded outward under extrusion and folded and contracted when the radial extrusion force is released.

[0006] In one embodiment, when the expandable section is in a folded state, the wall thickness at the position corresponding to the first wall thickness portion of the expandable section and the wall thickness at the position corresponding to the second wall thickness portion differ by less than or equal to 0.05 mm.

[0007] In one embodiment, the wall thickness of the first wall thickness part is 0.2 mm - 0.5 mm, and the wall thickness of the second wall thickness part is 0.4 mm - 2 mm; and / or, the outer diameter of the expandable section in the folded state is 3 mm - 10 mm, and the outer diameter of the expandable section in the expanded state is 6 mm - 15 mm. In one embodiment, a metal spring or an elastic braided structure is provided inside the second wall thickness part, or a coil structure formed by cutting a metal tube is provided inside the second wall thickness part.

[0008] In one embodiment, the expandable section includes an outer layer and an inner layer. The outer layer is a closed circle, the inner layer is a non-closed structure, the inner layer is arranged inside the outer layer, and the inner layer and the outer layer are stacked to form the second wall thickness part, and the part of the outer layer that is not stacked with the inner layer forms the first wall thickness part.

[0009] In one embodiment, the elasticity of the inner layer is less than that of the outer layer.

[0010] In one embodiment, the wall thickness at any position in the circumferential direction of the outer layer is the same, and the wall thickness of the outer layer is 0.02 mm - 0.15 mm.

[0011] In one embodiment, the inner layer includes a reinforcing layer and a polymer layer covering at least one side of the reinforcing layer.

[0012] In one embodiment, the material of the reinforcing layer is medical stainless steel or nitinol; and / or, the reinforcing layer is a spring wire winding, the pitch of the spring wire winding is 1 mm - 10 mm, and the diameter of the spring wire winding is 2 mm - 10 mm.

[0013] A catheter sheath includes the sheath tube as described above.

[0014] A delivery system includes the catheter sheath as described above.

[0015] For the above-mentioned sheath tube, catheter sheath and delivery system, the sheath tube includes an expandable section. The circumferential direction of the expandable section includes a connected first wall thickness part and a second wall thickness part. The thickness of the first wall thickness part is less than that of the second wall thickness part, and the first wall thickness part can be folded inward or outward, so that the expandable section can be radially expanded outward under extrusion and folded and contracted when the radial extrusion force is removed. Thus, the expandable and retractable properties of the expandable section are used to change the outer diameter, thereby expanding the applicable range of the sheath tube to establish a delivery channel in different blood vessels, and at the same time, it can also avoid blood vessel complications caused by stretching the blood vessel for a long time. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 Schematic structural diagram of a catheter sheath in one embodiment.

[0018] Figure 2 Schematic structural diagram when a device passes through the sheath tube of a catheter sheath in one embodiment.

[0019] Figure 3 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in an expanded state in one embodiment.

[0020] Figure 4 For Figure 3 Schematic cross-sectional structural diagram of the expandable section of the sheath tube shown in a folded state.

[0021] Figure 5 For Figure 3 Schematic cross-sectional structural diagram of the expandable section of the sheath tube shown in another folding mode.

[0022] Figure 6 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in an expanded state in another embodiment.

[0023] Figure 7 For Figure 6 Schematic cross-sectional structural diagram of the expandable section of the sheath tube shown in a folded state.

[0024] Figure 8 For Figure 6 Schematic cross-sectional structural diagram of the expandable section of the sheath tube shown in another folding mode.

[0025] Figure 9 Schematic cross-sectional structural diagram of the inner layer of the expandable section in a sheath tube in one embodiment.

[0026] Figure 10 Schematic structural diagram of the reinforcing layer provided in the inner layer of the expandable section in a sheath tube in one embodiment.

[0027] Figure 11 Schematic structural diagram of another structure of the reinforcing layer provided in the inner layer of the expandable section in a sheath tube in one embodiment.

[0028] Figure 12 Schematic structural diagram of yet another structure of the reinforcing layer provided in the inner layer of the expandable section in a sheath tube in one embodiment.

[0029] Reference numerals:

[0030] 100, catheter sheath; 10, sheath tube; 20, sheath base; 30, hemostatic valve; 40, evacuation tube; 50, three-way valve; 11, expandable section; 11a, squeezed portion; 11b, distal portion; 11c, proximal portion; 12, transition section; 13, tail section; 111, first wall thickness portion; 111a, first crease point; 111b, second crease point; 111c, third crease point; 111d, fourth crease point; 112, second wall thickness portion; 101, outer layer; 101a, fifth crease point; 101b, sixth crease point; 102, inner layer; 1021, reinforcing layer; 1022, first polymer layer; 1023, second polymer layer; 200, device; 200a, large-diameter component. Detailed implementation manners

[0031] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there can also be a middle element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a middle element at the same time.

[0033] The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions are only for the purpose of illustration and do not represent the only implementation manner.

[0034] It should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0035] It should be noted that the terms "distal end" and "proximal end" are used as orientation terms, which are commonly used terms in the field of interventional medical devices. The "distal end" refers to the end away from the operator (such as a doctor) during the operation, and the "proximal end" refers to the end close to the operator during the operation. Axial direction refers to the direction in which the central axis of the medical device extends; radial direction refers to the direction perpendicular to the above-mentioned axial direction.

[0036] Combined with Figure 1 and Figure 2 As shown in the figures, an embodiment of the present application provides a catheter sheath 100. The catheter sheath 100 includes a sheath tube 10, and the sheath tube 10 includes an expandable section 11, a transition section 12, and a tail section 13 that are connected in sequence. The transition section 12 is a tapered tube, and its large-diameter end is connected to the distal end of the tail section 13, and its small-diameter end is connected to the proximal end of the expandable section 11.

[0037] The expandable section 11 can be radially expanded outward under extrusion. For example, when a device 200 with a diameter larger than that of the sheath tube 10 passes through the sheath tube 10, the expandable section 11 will be radially expanded as the device 200 advances. At this time, the diameter of the part of the expandable section 11 that is radially extruded outward increases. As the device 200 advances, the part of the expandable section 11 that loses the radial outward extrusion of the device 200 retracts to the original non-expanded state. For the convenience of understanding, the larger-diameter part in the device 200 is hereinafter referred to as the "large-diameter component 200a", and the part of the expandable section 11 corresponding to the large-diameter component 200a during the process of passing through the expandable section 11 is referred to as the "extruded part 11a". Then, the extruded part 11a of the expandable section 11 is radially expanded outward under the extrusion of the large-diameter component 200a. As the device 200 advances axially relative to the sheath tube 10, the large-diameter component 200a moves within the expandable section 11, so that the position of the extruded part 11a corresponding to the large-diameter component 200a in the expandable section 11 also changes. Therefore, the extruded part 11a can also be understood as the part of the expandable section 11 that is radially expanded when the large-diameter component 200a moves within the expandable section 11. In some embodiments, the catheter sheath 100 further includes structures such as a sheath base 20, a hemostatic valve 30, a drainage tube 40, and a three-way valve 50. The proximal end of the sheath tube 10 is connected to the sheath base 20, the hemostatic valve 30 and the drainage tube 40 are both arranged on the sheath base 20, and the three-way valve 50 is connected to the drainage tube 40.

[0038] As Figure 2As shown, the expandable section 11 includes a portion located at the distal end of the squeezed portion 11a (hereinafter referred to as the "distal portion 11b") and a portion located at the proximal end of the squeezed portion 11a (hereinafter referred to as the "proximal portion 11c"). During the process of the large-diameter component 200a moving axially along the expandable section 11 from the proximal end to the distal end, the position of the squeezed portion 11a moves towards the distal end. After the large-diameter component 200a moves away, the proximal portion 11c loses the extrusion of the large-diameter component 200a, so that the proximal portion 11c retracts to its original non-expanded state. Correspondingly, the distal portion 11b, as the portion that the large-diameter component 200a has not passed through, maintains its original non-expanded state. Thus, during the process of the large-diameter component 200a moving towards the distal end, the length of the proximal portion 11c located at the proximal end of the squeezed portion 11a gradually increases, and the length of the distal portion 11b located at the distal end of the squeezed portion 11a gradually decreases.

[0039] It should be noted that the expandable section 11 can adopt various possible structures to achieve radial expansion and retraction. For the convenience of understanding, the structure of the sheath tube 10 will be further described below in combination with the structure of the expandable section 11.

[0040] In some embodiments, the expandable section 11 can be a single-layer winding structure, and the wall thickness at different circumferential positions of the single-layer winding structure is different. For the convenience of understanding, taking the expandable section 11 in a fully expanded state as an example, in combination with Figure 3 As shown, the expandable section 11 includes a first wall thickness portion 111 and a second wall thickness portion 112 connected to each other in the circumferential direction. The first wall thickness portion 111 and the second wall thickness portion 112 are joined in the circumferential direction of the expandable section 11 to jointly enclose a complete cavity to ensure the sealing performance of the expandable section 11. In this embodiment, the thickness of the first wall thickness portion 111 is less than the thickness of the second wall thickness portion 112. In combination with Figure 4 and Figure 5 As shown, the first wall thickness portion 111 can be folded inwards or outwards, so that the expandable section 11 can be extruded to expand radially outwards and fold and contract when the radial extrusion force is removed. In this way, the expandable section 11 can change its outer diameter through expansion and retraction, thereby expanding the applicable range of the sheath tube 10 to establish a delivery channel in different blood vessels, and at the same time, it can also avoid causing blood vessel complications due to stretching the blood vessel for a long time.

[0041] The ways to achieve the foldability of the first wall thickness portion 111 include but are not limited to heat treatment or shaping under a certain pressure.

[0042] The tube wall material of the expandable section 11 can be selected from materials with a certain rigidity and resilience. For example, PTFE or PE, etc., so as to return to the folded and contracted state when the radial extrusion force is removed after expansion.

[0043] When the expandable section 11 is in a folded state, the wall thickness at the position corresponding to the first wall thickness portion 111 of the expandable section 11 is close to the wall thickness at the position corresponding to the second wall thickness portion 112. For example, when the expandable section 11 is in a folded state, the difference between the wall thickness at the position corresponding to the first wall thickness portion 111 of the expandable section 11 and the wall thickness at the position corresponding to the second wall thickness portion 112 is less than or equal to 0.05 mm. In this way, the stress in the circumferential direction of the expandable section 11 is more uniform, preventing fracture or bending caused by stress concentration at the mutation.

[0044] The expandable section 11 can have different folding methods. For the sake of easy understanding, the folding method of the expandable section 11 will be described below by taking the position and number of crease points generated at the bending position in the folded state as an example, but it is not a limitation on the folding method of the expandable section 11.

[0045] Combined with Figure 4 As shown, when the expandable section 11 is in a folded state, the first wall thickness portion 111 has two crease points that are radially and circumferentially staggered, specifically the first crease point 111a and the second crease point 111b, where the first crease point 111a is radially outward of the second crease point 111b. The first wall thickness portion 111 can also adopt other folding methods. Different folding methods result in different numbers of crease points. For example, combined with Figure 5 As shown, when the expandable section 11 is in a folded state, the first wall thickness portion 111 folds inward and overlaps. In this way, the end of the overlapping position of the first wall thickness portion 111 has two third crease points 111c, and two fourth crease points 111d are also formed at the junction between the first wall thickness portion 111 and the second wall thickness portion 112 when the first wall thickness portion 111 folds inward.

[0046] In some embodiments, the wall thickness of the first wall thickness portion 111 is 0.2 mm - 0.5 mm, and the wall thickness of the second wall thickness portion 112 is 0.4 mm - 2 mm. For example, the wall thickness of the first wall thickness portion 111 is 0.2 mm, and the wall thickness of the second wall thickness portion 112 is 0.4 mm. Or, the wall thickness of the first wall thickness portion 111 is 0.5 mm, and the wall thickness of the second wall thickness portion 112 is 2 mm. Or, the wall thickness of the first wall thickness portion 111 is 0.2 mm, and the wall thickness of the second wall thickness portion 112 is 2 mm. Again, for example, the wall thickness of the first wall thickness portion 111 is 0.3 mm, and the wall thickness of the second wall thickness portion 112 is 1.2 mm. The wall thickness of the first wall thickness portion 111 and the wall thickness of the second wall thickness portion 112 are not limited herein. It should be noted here that for the position with uneven wall thickness, the wall thicknesses of the first wall thickness portion 111 and the second wall thickness portion 112 are both average thicknesses.

[0047] The initial outer diameter of the expandable section 11 is 3 mm - 10 mm to facilitate the expansion and folding of the expandable section 11. For example, the initial outer diameter of the expandable section 11 is 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. It should be noted here that the initial outer diameter of the expandable section 11 is the outer peripheral diameter of the expandable section 11 in the original non-expanded state, and can also be understood as the outer peripheral diameter of the expandable section 11 in the folded state.

[0048] The inventors found through research that when the initial outer diameter of the expandable section 11 is set to 4 mm - 6 mm, the best expansion and folding shrinkage effects can be obtained, and it can adapt to the smooth passage requirements of devices 200 such as balloons, inner tubes and outer tubes.

[0049] In some embodiments, the outer peripheral diameter of the expandable section 11 in the expanded state can be 6 mm - 15 mm. For example, the outer peripheral diameter of the expandable section 11 in the expanded state is 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm. The inventors found through research that when the outer peripheral diameter of the expandable section 11 in the expanded state is set to 6 mm - 8 mm, the expansion and folding shrinkage effects of the expandable section 11 can be improved, and it can adapt to the smooth passage requirements of devices 200 such as balloons, inner tubes and outer tubes.

[0050] In some embodiments, a metal spring or an elastic braided structure can be provided inside the second wall thickness portion 112, or a coil structure formed by cutting a metal tube is provided inside the second wall thickness portion 112 to improve the recovery rate and anti-torsion performance.

[0051] In some embodiments, the expandable section 11 can be a double-layer structure or a multi-layer structure with more than 2 layers. Figure 6 As shown, taking the expandable section 11 including an outer layer 101 and an inner layer 102 as an example, the outer layer 101 of the expandable section 11 is a closed circle to ensure the sealing performance of the expandable section 11. The inner layer 102 is a non-closed structure, and the inner layer 102 is arranged inside the outer layer 101, so that the expandable section 11 forms opposite first wall thickness portion 111 and second wall thickness portion 112. Specifically, the inner layer 102 and the outer layer 101 are superimposed to form the second wall thickness portion 112 of the expandable section 11, and the part of the outer layer 101 that is not superimposed on the inner layer 102 forms the first wall thickness portion 111 of the expandable section 11. Figure 6 As shown in the cross-sectional structure of the expandable section 11 shown, the inner layer 102 can be C-shaped. Relative to the outer layer 101, the inner layer 102 has less elasticity to provide a certain stiffness and retraction force, facilitating the smooth retraction of the expandable section 11 when the radial extrusion force is released after expansion. The inner layer 102 and the outer layer 101 can be heat-melted together, so that the outer layer 101 is stably coated on the outside of the inner layer 102.

[0052] The wall thickness of the outer layer 101 of the expandable section 11 is consistent at any circumferential position. For example, the wall thickness of the outer layer 101 is 0.02 mm - 0.15 mm, preferably 0.08 mm. In this way, the outer layer 101 is not easily torn, and after the expandable section 11 is folded, the outer layer 101 has little influence on the overall wall thickness of the expandable section 11. Further, the wall thickness of the outer layer 101 can be 0.06 mm - 0.1 mm to reduce the influence of the outer layer 101 on the overall wall thickness of the expandable section 11, and at the same time, the outer layer 101 is easy to fold.

[0053] The outer layer 101 can further adopt a tear-resistant material. For example, the material of the outer layer 101 is PTFE (Poly tetrafluoroethylene). The inner layer 102 can adopt materials such as HDPE (High Density Polyethylene), Pebax (block polyether amide resin) or PA (Polyamide) to obtain appropriate strength.

[0054] In this embodiment, the expandable section 11 can be folded and contracted in an outward folding manner or an inward folding manner, which is not limited herein. For example, as shown in Figure 7 When the expandable section 11 is in a folded state, the inner layer 102 has an overlapping part, and the folded part of the outer layer 101 is located at the overlapping part of the inner layer 102 that is clamped. At this time, the outer layer 101 has two crease points that are radially and circumferentially staggered, specifically the fifth crease point 101a and the sixth crease point 101b, where the first crease point 111a is radially outward of the second crease point 111b. Another example, as shown in Figure 8 When the expandable section 11 is in a folded state, the two ends of the inner layer 102 are opposed to each other in the circumferential direction and do not have an overlapping part, and the outer layer 101 is folded inside the inner layer 102, and the outer layer 101 itself has an overlapping part that is folded on each other. The examples listed here are only for facilitating the understanding of the folding method of the expandable section 11, and the folding method of the expandable section 11 is not limited to this. In some embodiments, the expandable section 11 can also adopt other folding methods, which will not be elaborated herein.

[0055] In some embodiments, as shown in Figure 9As shown, the inner layer 102 of the expandable section 11 includes a reinforcing layer 1021 and a polymer layer covering at least one side of the reinforcing layer 1021. Taking the example that polymer layers are covered on both the inner and outer sides of the reinforcing layer 1021, the inner layer 102 includes a first polymer layer 1022 and a second polymer layer 1023. The first polymer layer 1022 is covered on the inner side of the reinforcing layer 1021, and the second polymer layer 1023 is covered on the outer side of the reinforcing layer 1021. Based on the fact that the inner layer 102 is a non-closed structure, the first polymer layer 1022 and the second polymer layer 1023 can be joined at the end of the reinforcing layer 1021 to form an integral body, thereby increasing the connection stability with the reinforcing layer 1021.

[0056] The material of the reinforcing layer 1021 can be medical stainless steel or nitinol alloy. The processing method of the inner layer 102 can be directly melting the reinforcing structure between the first polymer layer 1022 and the second polymer layer 1023 during extrusion. In some embodiments, an inner pipe fitting, the reinforcing layer 1021, and an outer pipe fitting can also be sleeved in sequence, and then a heat-shrinkable tube is sleeved, and the inner pipe fitting, the reinforcing layer 1021, and the outer pipe fitting are combined together by a hot-melt method to form the inner layer 102 of the expandable section 11. Among them, both the inner pipe fitting and the outer pipe fitting can be made of polymer materials.

[0057] The reinforcing layer 1021 can be a spring winding or a metal tube cutting structure to enhance the resilience performance and torsional control performance of the expandable section 11. In some embodiments, combined Figure 10 As shown, when the reinforcing layer 1021 is a spring winding, the spring wire can be a flat wire or a round wire. The pitch of the spring winding can be 1 mm - 10 mm. For example, the pitch of the spring winding is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. The diameter of the spring winding can be 2 mm - 10 mm. For example, the diameter of the spring winding is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. Combined Figure 11 and Figure 12 As shown, the reinforcing layer 1021 can also be formed by laser cutting a metal tube. The material of the metal tube can be medical stainless steel. The diameter of the metal tube can be 2 mm - 10 mm, and the wall thickness can be 0.1 mm - 0.5 mm. In some embodiments, the diameter of the metal tube is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, and the wall thickness is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0058] In some embodiments, a hydrophilic coating can be applied to the inside or outside of the sheath 10 to reduce the friction force. A PTFE layer can also be covered on the inner side of the first polymer layer 1022 to improve the smoothness and facilitate the smooth passage of the device 200 through the sheath 10.

[0059] Based on the catheter sheath 100 provided by the embodiments of the present application, another embodiment of the present application provides a delivery system including the catheter sheath 100. Since the sheath tube 10 of the catheter sheath 100 is provided with an expandable section 11 to utilize the expandability and retractability of the expandable section 11 to change the outer diameter, thereby expanding the applicable range of the sheath tube 10 to establish a delivery channel in different blood vessels, and at the same time, it can also avoid blood vessel complications caused by stretching the blood vessel for a long time. Therefore, when performing a surgery using the delivery system including the catheter sheath 100, the surgical effect can be improved.

[0060] It should be noted that, in the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0061] In the present application, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0062] In the present application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium.

[0063] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0064] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A sheath tube, characterized in that: The sheath tube includes an expandable section, which circumferentially includes a first wall thickness portion and a second wall thickness portion connected to each other, the thickness of the first wall thickness portion is less than the thickness of the second wall thickness portion, and the first wall thickness portion can be folded inward or outward, so that the expandable section can be squeezed to expand radially outward, and fold and contract when the radial squeezing force is released.

2. The sheath tube according to claim 1, characterized in that: When the expandable section is in a folded state, the difference between the wall thickness of the expandable section at a position corresponding to the first wall thickness portion and the wall thickness of the expandable section at a position corresponding to the second wall thickness portion is less than or equal to 0.05 mm.

3. The sheath tube according to claim 1, characterized in that: The wall thickness of the first thick wall portion is 0.2 mm to 0.5 mm, and the wall thickness of the second thick wall portion is 0.4 mm to 2 mm; And / or, the outer diameter of the expandable section in the folded state is 3mm-10mm, and the outer diameter of the expandable section in the expanded state is 6mm-15mm.

4. The sheath tube according to claim 1, characterized in that: A metal spring or an elastic braided structure is provided in the second thick wall portion, or a coil structure formed by cutting a metal tube is provided in the second thick wall portion.

5. The sheath tube according to claim 1, characterized in that: The expandable section includes an outer layer and an inner layer, the outer layer is a closed circle, the inner layer is a non-closed structure, the inner layer is arranged on the inner side of the outer layer, the inner layer and the outer layer are overlapped to form the second wall thickness portion, and the portion of the outer layer not overlapped with the inner layer forms the first wall thickness portion.

6. The sheath tube according to claim 5, characterized in that: The inner layer has less elasticity than the outer layer.

7. The sheath tube according to claim 5, characterized in that: The wall thickness of the outer layer at any position in the circumferential direction is consistent, and the wall thickness of the outer layer is 0.02mm-0.15mm.

8. The sheath tube according to claim 5, characterized in that: The inner layer includes a reinforcement layer and a polymer layer covering at least one side of the reinforcement layer.

9. The sheath tube according to claim 8, characterized in that: The material of the reinforcement layer is medical stainless steel or nickel-titanium alloy; And / or, the reinforcement layer is a spring winding, the pitch of the spring winding is 1mm-10mm, and the diameter of the spring winding is 2mm-10mm.

10. A catheter sheath, characterized in that: Comprising the sheath tube as described in any one of claims 1-9.

11. A conveying system, characterized in that: Comprising the catheter sheath according to claim 10.

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