Sheath tube, catheter sheath and delivery system

Abstract

The utility model relates to a sheath tube, a catheter sheath and a delivery system.The sheath tube comprises an expandable section, the expandable section comprises an elastic part and a rigid part which are connected, the elastic part and the rigid part jointly define a tube cavity, and the elastic part is stretchable so that the expandable section can be extruded to expand outwards in the radial direction; and when the radial extrusion acting force is relieved, the elastic part shrinks to pull the rigid part to reset. 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] As an effective treatment for senile valvular degenerative diseases, the transcatheter valve implantation in interventional therapy does not require the patient to undergo a high-risk thoracotomy procedure. This technique 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 be opened, 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 cannot cover the blood vessels of all patients and the situation where there are calcifications in the blood vessels. Moreover, the sheath tube needs to be continuously involved in the whole process of the interventional surgery, and stretching the blood vessels for a long time will cause more vascular complications. Summary of the Invention

[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, the sheath tube includes an expandable section, the expandable section includes a connected elastic part and a rigid part, the elastic part and the rigid part jointly enclose a lumen, and the elastic part is stretchable, so that the expandable section can be radially expanded under extrusion, and when the radial extrusion force is released, the elastic part contracts to drive the rigid part to move back to its original position.

[0006] In one embodiment, the rigid part has at least one notch, and the elastic part fills the notch.

[0007] In one embodiment, the wall thickness of the elastic part is greater than or equal to the wall thickness of the rigid part; and / or, the wall thickness of the rigid part is 0.1 mm - 2 mm, when the expandable section is in the expanded state, the elastic part elongates 2 to 6 times relative to the original length.

[0008] In one embodiment, the inner diameter of the expandable section in the contracted state is 3 mm - 10 mm.

[0009] In one embodiment, the elastic part is a closed circle, the rigid part is a non-closed structure, and the rigid part is arranged inside the elastic part.

[0010] In one embodiment, the wall thickness of the elastic part is 0.05 mm - 0.5 mm; and / or, the wall thickness of the rigid part is 0.1 mm - 1 mm.

[0011] In one embodiment, both the elastic part and the rigid part are closed circles. The rigid part is arranged inside the elastic part. The rigid part has indentations extending along the axial direction of the expandable section. When the expandable section is squeezed and expands radially outward, the rigid part tears along the indentations to form a non-closed structure.

[0012] In one embodiment, the rigid part is a multi-layer structure, or the material of the rigid part is medical stainless steel, nitinol alloy or rigid medical polymer material.

[0013] In one embodiment, the rigid part is a metal wire braided structure, and the diameter of the metal wire used in the metal wire braided structure is 0.02 mm - 0.5 mm; or, the rigid part is a spring winding, the pitch of the spring winding is 0.1 mm - 0.3 mm, and the diameter of the spring winding is 2 mm - 8 mm; or, the rigid part is cut from a metal tube, the wall thickness of the metal tube is 0.02 mm - 0.3 mm, and the inner diameter of the metal tube is 2 mm - 8 mm.

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

[0015] A delivery system includes the catheter sheath as described above.

[0016] For the sheath tube, catheter sheath and delivery system as described above, the sheath tube includes an expandable section. The circumferential direction of the expandable section includes a connected elastic part and a rigid part. The elastic part and the rigid part jointly enclose a lumen, and the elastic part can be stretched, so that the expandable section can be squeezed and expand radially outward, and contract when the radial squeezing 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order 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 use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a catheter sheath in an embodiment.

[0019] Figure 2 Schematic structural diagram when a device passes through the sheath tube of a catheter sheath in an embodiment.

[0020] Figure 3 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in an embodiment.

[0021] Figure 4 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in another embodiment.

[0022] Figure 5 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in yet another embodiment.

[0023] Figure 6 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in still another embodiment.

[0024] Figure 7 Schematic cross-sectional structural diagram of the expandable section of a sheath tube in yet another embodiment.

[0025] Figure 8 Schematic three-dimensional structural diagram when indentations are provided on the rigid part of the expandable section in a sheath tube of an embodiment.

[0026] Figure 9 Schematic cross-sectional structural diagram when indentations are provided on the rigid part of the expandable section in a sheath tube of an embodiment.

[0027] Figure 10 Schematic three-dimensional diagram of the rigid part of the expandable section in a sheath tube of an embodiment.

[0028] Figure 11 Schematic three-dimensional diagram of the rigid part of the expandable section in a sheath tube of another embodiment.

[0029] Figure 12 Schematic three-dimensional diagram of the rigid part of the expandable section in a sheath tube of yet another embodiment.

[0030] Reference numerals:

[0031] 100, catheter sheath; 10, sheath tube; 20, sheath base; 30, hemostatic valve; 40, drain tube; 50, three-way valve; 11, expandable section; 11a, squeezed part; 11b, distal part; 11c, proximal part; 12, transition section; 13, tail section; 111, elastic part; 112, rigid part; 112a, notch; 112b, indentation; 200, device; 200a, large-diameter component. Detailed implementation manners

[0032] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of 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.

[0033] 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 may also be an intermediate 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 an intermediate element at the same time.

[0034] The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions are for illustrative purposes only and do not represent the only implementation manner.

[0035] 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 cannot be understood as a limitation to the present application.

[0036] It should be noted that when using "distal end" and "proximal end" as orientation terms, these orientation terms are common terms in the field of interventional medical devices. Among them, the "distal end" refers to the end far 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 refers to the direction in which the central axis of the medical device extends; radial refers to the direction perpendicular to the above axial direction.

[0037] Combined Figure 1 and Figure 2 As shown, the embodiment of the present application provides a catheter sheath 100. The catheter sheath 100 includes a sheath tube 10. The sheath tube 10 includes a dilatable 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 dilatable section 11.

[0038] The expandable section 11 can be squeezed and expand radially outward. For example, when a device 200 with a diameter larger than that of the sheath 10 passes through the sheath 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 outwardly squeezed increases. As the device 200 advances, the part of the expandable section 11 that loses the radial outward squeezing of the device 200 retracts to its original non-expanded state. For the sake of easy understanding, hereinafter, the larger-diameter part in the device 200 is 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 "squeezed part 11a". Then, the squeezed part 11a of the expandable section 11 expands radially outward under the squeezing of the large-diameter component 200a. As the device 200 advances axially relative to the sheath 10, the large-diameter component 200a moves within the expandable section 11, so that the position of the squeezed part 11a corresponding to the large-diameter component 200a in the expandable section 11 also changes. Therefore, the squeezed 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 drain tube 40, and a three-way valve 50. The proximal end of the sheath 10 is connected to the sheath base 20. The hemostatic valve 30 and the drain tube 40 are both provided on the sheath base 20. The three-way valve 50 is connected to the drain tube 40.

[0039] As Figure 2 shown, the expandable section 11 includes a part located at the distal end of the squeezed part 11a (hereinafter referred to as the "distal part 11b") and a part located at the proximal end of the squeezed part 11a (hereinafter referred to as the "proximal part 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 part 11a moves towards the distal end. The proximal part 11c after the large-diameter component 200a moves away loses the squeezing of the large-diameter component 200a, so that the proximal part 11c retracts to its original non-expanded state. Correspondingly, the distal part 11b, as the part 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 part 11c located at the proximal end of the squeezed part 11a gradually increases, and the length of the distal part 11b located at the distal end of the squeezed part 11a gradually decreases.

[0040] It should be noted that the expandable section 11 can adopt various possible structures to achieve radial expansion and retraction. For the sake of easy understanding, hereinafter, the structure of the sheath 10 will be further described in combination with the structure of the expandable section 11. In combination with Figure 3As shown, the expandable section 11 includes a connected elastic part 111 and a rigid part 112. The elastic part 111 and the rigid part 112 jointly enclose a lumen to enable the lumen to meet the need for the device 200 to pass through the sheath 10. The elastic part 111 is stretchable, so that the expandable section 11 can be radially expanded outward under extrusion. When the radial extrusion force is released, the elastic part 111 contracts to pull the rigid part 112 to reset. Thus, after the large-diameter component 200a of the device 200 passes through the lumen of the expandable section 11, the part of the expandable section 11 that loses the radial outward extrusion of the device 200 retracts.

[0041] In some embodiments, the part of the expandable section 11 that loses the radial outward extrusion of the device 200 can recover 80% to 100% of the deformation. Among them, the part of the expandable section 11 that loses the radial outward extrusion of the device 200 recovering 100% of the deformation means that the expandable section 11 retracts to the original non-expanded state.

[0042] The material of the elastic part 111 is medical silicone rubber or PU (Polyurethane). The material of the rigid part 112 can be PA (Polyamide), Pebax (block polyether amide resin), PTFE (Poly tetrafluoroethylene), or PE (Polyethylene). The materials of the elastic part 111 and the rigid part 112 are not limited herein.

[0043] In some embodiments, the rigid part 112 has at least one notch 112a, and the elastic part 111 is filled in the notch 112a. It can be understood that the number of the elastic parts 111 is the same as the number of the notches 112a. The elastic parts 111 are respectively filled in the corresponding notches 112a, and the elastic parts 111 arranged in the notches 112a are used to connect the ends of the rigid part 112 to jointly enclose a lumen. When the large-diameter component 200a of the device 200 passes through the lumen, the large-diameter part generates a radially outward expansion force on the inner wall of the lumen, so that the elastic part 111 is stretched to adapt to the outward expansion of the expandable section 11. The number of the notches 112a and the elastic parts 111 is not limited herein. For example, as Figure 3 shown, the number of the notches 112a can be 1, and correspondingly, the elastic part 111 is also 1. For another example, as Figure 4 shown, the number of the notches 112a is 2, and correspondingly, the elastic part 111 is also 2. The two elastic parts 111 are respectively filled in the two notches 112a. Combining Figure 5 , the number of the notches 112a can be 4, and correspondingly, the elastic part 111 is also 4. The four elastic parts 111 are respectively filled in the four notches 112a.

[0044] The wall thickness of the elastic part 111 is greater than or equal to that of the rigid part 112. In this way, after the expandable section 11 expands outward, the elastic part 111 will not be stretched too thin and prone to rupture. In addition, considering that the elastic part 111 provides elastic deformation in the sheath 10 to adapt to the expansion and retraction of the expandable section 11, the material stiffness of the elastic part 111 is weak. In this embodiment, by setting the wall thickness of the elastic part 111 to be greater than that of the rigid part 112, the supporting force of the elastic part 111 can be increased, thereby improving the overall anti-bending ability and torsion control performance of the expandable section 11.

[0045] The wall thickness of the rigid part 112 is 0.1 mm - 2 mm. It can be understood that in the embodiment where the elastic part 111 fills the notch 112a, when the wall thickness of the elastic part 111 is equal to that of the rigid part 112, the wall thickness of the rigid part 112 is also the wall thickness at any position of the expandable section 11. By setting the wall thickness of the rigid part 112 to 0.1 mm - 2 mm, the rigid part 112 can have good supporting performance and at the same time can also meet the need to adapt to the bending along the blood vessel. The wall thickness of the rigid part 112 can specifically be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.7 mm, 0.9 mm, 1.3 mm, 1.5 mm or 2 mm.

[0046] When the expandable section 11 is in the expanded state, the elastic part 111 elongates 2 to 6 times relative to the original length, thereby increasing the diameter difference between the expanded and retracted states of the expandable section 11, that is, increasing the diameter change range of the expandable section 11 to expand the applicable range of the sheath 10 to establish a delivery channel in different blood vessels. In some embodiments, when the expandable section 11 is in the expanded state, the elastic part 111 elongates 2 times, 3 times or 6 times relative to the original length.

[0047] The inner diameter of the expandable section 11 in the contracted state is 3 mm - 10 mm, so that the size of the sheath 10 is suitable for passing through the blood vessel. The inner diameter of the expandable section 11 in the contracted state refers to the inner peripheral diameter of the expandable section 11 in the original non-expanded state. In some embodiments, the inner diameter of the expandable section 11 in the contracted state can be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. Regarding the size of the expandable section 11, no limitation is made here.

[0048] The elastic part 111 is not limited to filling the notch 112a to jointly enclose a lumen with the rigid part 112. In some embodiments, the elastic part 111 and the rigid part 112 can also be stacked in the radial direction of the expandable section 11. For example, in combination with Figure 6As shown, the elastic part 111 is a closed circle, and the rigid part 112 is a non-closed structure. The rigid part 112 is disposed inside the elastic part 111. It can be understood that the non-closed structure of the rigid part 112 means that a notch 112a is formed in the circumferential direction. The number of notches 112a can be 1, or 2 or more. For example, in combination with Figure 7 As shown, the rigid part 112 has 2 notches 112a.

[0049] In this embodiment, the elastic part 111 is a closed circle, thus serving as the outer layer of the expandable section 11. The elastic part 111 can provide good sealing performance. The rigid part 112 is disposed inside the elastic part 111, so that the good rigidity of the rigid part 112 can endow the expandable section 11 with good anti-bending performance and torsion control performance, which is beneficial for the sheath 10 to enter the blood vessel to establish a delivery channel.

[0050] The wall thickness of the elastic part 111 is 0.05 mm - 0.5 mm. For example, the wall thickness of the elastic part 111 is 0.05 mm, 0.13 mm, 0.25 mm or 0.5 mm. The wall thickness of the rigid part 112 is 0.1 mm - 1 mm. For example, the wall thickness of the rigid part 112 is 0.1 mm, 0.25 mm, 0.5 mm or 1 mm. By setting the wall thickness of the elastic part 111 to 0.05 mm - 0.5 mm and the wall thickness of the rigid part 112 to 0.1 mm - 1 mm, the support performance of the sheath 10 can be satisfied, and it can be well expanded when subjected to a radially outward extrusion force. When the radial force is released, the elastic part 111 contracts, and the rigid part 112 can be conveniently pulled back to its original position, realizing the retraction of the expandable section 11.

[0051] In combination with Figure 8 and Figure 9 As shown, in some embodiments, both the elastic part 111 and the rigid part 112 are closed circles. The rigid part 112 is disposed inside the elastic part 111. The rigid part 112 has an indentation 112b extending along the axial direction of the expandable section 11. It can be understood that the indentation 112b can be formed by stamping or shearing the rigid part 112 to make it thinner, so that the position corresponding to the indentation 112b is easily torn. When the expandable section 11 is extruded and expands radially outward, the rigid part 112 tears along the indentation 112b to form a non-closed structure. In this embodiment, the tearability of the rigid part 112 at the position along the indentation 112b is utilized to adapt to the diameter change of the expandable section 11 when it is subjected to a radially outward extrusion.

[0052] The rigid part 112 is made of medical stainless steel or nitinol. To enhance the resilience and torsional control performance, the rigid part 112 adopts structures such as metal wire braiding, spring winding, or metal tube cutting. In some embodiments, the material of the rigid part 112 can also be a rigid medical polymer material.

[0053] It should be noted that, in some embodiments, the rigid part 112 can be a multi-layer structure, that is, the rigid part 112 includes multiple material layers, specifically it can be 2 layers, or 3 layers or more than 3 layers, which is not limited here. For example, in some embodiments, the rigid part 112 includes a metal support layer and a medical polymer material layer covering at least one side of the metal support layer. The material of the metal support layer includes but is not limited to stainless steel or nitinol. The material of the medical polymer material layer includes but is not limited to polyurethane, polycarbonate, polyethylene, silicone resin, silicone rubber, or polyvinyl chloride.

[0054] In some embodiments, the rigid part 112 is a metal wire braided structure, and the diameter of the metal wire used in the metal wire braided structure is 0.02 mm - 0.5 mm. The diameter of the metal wire can specifically be 0.02 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm.

[0055] Combined Figure 10 As shown, in some embodiments, the rigid part 112 is a spring winding, the pitch of the spring winding is 0.1 mm - 0.3 mm, and the diameter of the spring winding is 2 mm - 8 mm. In some embodiments, the pitch of the spring winding is 0.1 mm and the diameter of the spring winding is 2 mm; or, the pitch of the spring winding is 0.3 mm and the diameter of the spring winding is 2 mm; or, the pitch of the spring winding is 0.3 mm and the diameter of the spring winding is 8 mm. In some embodiments, the pitch of the spring winding is 0.2 mm and the diameter of the spring winding is 5 mm.

[0056] Combined Figure 11 and Figure 12 As shown, the rigid part 112 is cut from a metal tube, and the material of the metal tube includes but is not limited to a medical stainless steel tube. The thickness of the wall of the metal tube is 0.02 mm - 0.3 mm, and the inner diameter of the metal tube is 2 mm - 8 mm. In some embodiments, the thickness of the wall of the metal tube is 0.02 mm and the inner diameter of the metal tube is 2 mm; or, the thickness of the wall of the metal tube is 0.3 mm and the inner diameter of the metal tube is 8 mm; or, the thickness of the wall of the metal tube is 0.02 mm and the inner diameter of the metal tube is 8 mm. In some embodiments, the thickness of the wall of the metal tube is 0.2 mm and the inner diameter of the metal tube is 5 mm.

[0057] In some embodiments, a hydrophilic coating may be applied to the inside or outside of the sheath tube 10 to reduce the frictional force. In the embodiment where the rigid portion 112 is disposed inside the elastic portion 111, a PTFE layer may also be provided on the inside of the rigid portion 112 to improve the smoothness and facilitate the smooth passage of the device 200 through the sheath tube 10.

[0058] 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, the expandable and retractable properties of the expandable section 11 are utilized to change the outer diameter, thereby expanding the applicable range of the sheath tube 10 for establishing a delivery channel in different blood vessels. 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.

[0059] 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.

[0060] 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 elements or the interaction relationship between two elements, unless otherwise clearly defined. 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.

[0061] 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.

[0062] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of 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 described in this specification.

[0063] The above embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on 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 modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A sheath tube, characterized in that: The sheath tube includes an expandable section, which includes an elastic part and a rigid part connected to each other. The elastic part and the rigid part together enclose a lumen, and the elastic part is stretchable so that the expandable section can be squeezed and expanded radially outward. When the radial squeezing force is released, the elastic part contracts to pull the rigid part to reset.

2. The sheath tube according to claim 1, characterized in that: The rigid part has at least one notch, and the elastic part fills the notch.

3. The sheath tube according to claim 2, characterized in that: The wall thickness of the elastic part is greater than or equal to the wall thickness of the rigid part; And / or, the wall thickness of the rigid part is 0.1 mm-2 mm, and when the expandable section is in the expanded state, the elastic part is stretched 2 to 6 times relative to the original length.

4. The sheath tube according to claim 2, characterized in that: The inner diameter of the expandable section in the contracted state is 3mm-10mm.

5. The sheath tube according to claim 1, characterized in that: The elastic part is a closed circle, the rigid part is a non-closed structure, and the rigid part is arranged on the inner side of the elastic part.

6. The sheath tube according to claim 5, characterized in that: The wall thickness of the elastic part is 0.05mm-0.5mm; and / or the wall thickness of the rigid part is 0.1mm-1mm.

7. The sheath tube according to claim 5, characterized in that: The elastic part and the rigid part are both closed circles. The rigid part is arranged on the inner side of the elastic part. The rigid part has an indentation extending along the axial direction of the expandable section. When the expandable section is squeezed and expanded radially outward, the rigid part is torn along the indentation to form a non-closed structure.

8. The sheath tube according to claim 5, characterized in that: The rigid part is a multi-layer structure, or the material of the rigid part is medical stainless steel, nickel-titanium alloy or rigid medical polymer material.

9. The sheath tube according to claim 5, characterized in that: The rigid part is a metal wire braided structure, and the diameter of the metal wire used in the metal wire braided structure is 0.02mm-0.5mm; Alternatively, the rigid part is a spring winding, the pitch of the spring winding is 0.1 mm-0.3 mm, and the diameter of the spring winding is 2 mm-8 mm; Alternatively, the rigid part is cut from a metal tube, the thickness of the tube wall of the metal tube is 0.02 mm-0.3 mm, and the inner diameter of the metal tube is 2 mm-8 mm.

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.

Images