A covered stent system

Abstract

The application discloses a covered stent system, and relates to the technical field of interventional medical devices, which comprises a delivery device and a covered stent with a pullable and soluble braided rope cover. The delivery device comprises an inner core tube, and the covered stent is a self-expanding structure which is sleeved on the outer periphery of the inner core tube and has a twisted and retracted state of being twisted by a certain angle with the axial direction as the rotation center and being bound by the pullable and soluble braided rope cover and an unfolded state of being unfolded radially outward after the binding is released. The pullable and soluble braided rope cover is a pullable and soluble braided structure in which the binding lines are cross-hooked along a braiding path and all the cross points are slipknots. The pullable and soluble braided rope cover has a bound connection state of being bound on the outer periphery of the covered stent and a released state of being pulled and solved into the binding lines. The covered stent system can pull the binding lines to solve the pullable and soluble braided rope cover, so that the covered stent is released. Moreover, the covered stent is twisted and rotated and then bound by the binding lines, so that the overall diameter of the covered stent during transportation is smaller, and the covered stent is more conducive to being transported in a blood vessel.

Description

Technical Field

[0001] This invention relates to the field of interventional medical device technology, specifically to a covered stent system. Background Technology

[0002] For the treatment of vascular lesions, existing technologies involve implanting covered stents at the site of the vascular lesion. The covered stents support the inner wall of the blood vessel, seal the vascular rupture, or isolate the blood supply to the inner wall of the hemangioma, thus establishing a new blood flow channel.

[0003] When a covered stent is fabricated, it needs to be compressed to a smaller size and assembled into a delivery system. The delivery system then transports the covered stent to the intended site and releases it via the vascular access. During delivery, after the covered stent is delivered to the expected location, the outer sheath is slowly withdrawn, the covered stent expands on its own, the delivery system is withdrawn, and the procedure is complete. However, the current covered stents, even when radially compressed, are still relatively large. The delivery system requires a larger outer sheath to restrict the compressed covered stent, resulting in poor intravascular passage.

[0004] Therefore, how to develop a covered stent system that can compress the overall diameter of the covered stent to make it easier to deliver it in blood vessels is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a covered stent system to solve the problem that the outer diameter of the existing covered stent is large when it is in a contracted state, which is not conducive to its delivery in blood vessels.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A covered scaffold system, comprising:

[0008] Conveyor, including inner core tube;

[0009] The film-coated support is a self-expanding structure sleeved on the outer periphery of the inner core tube. It has a torsional retraction state in which it is twisted at a certain angle around its own axis and is bound by a retractable braided rope, and an unfolded state in which it expands radially outward after the binding of the retractable braided rope is released.

[0010] The retractable braided cord is a retractable braided structure in which binding threads are interlocked along the braiding path and all intersections are slip knots. The retractable braided cord has a bound connection state in which multiple slip knots are woven and bound to the inner core tube and the outer periphery of the coated support in a twisted and retracted state, and a release state in which it is pulled apart into binding threads under external force and released from the binding of the coated support. When the retractable braided cord is in the bound connection state, the coated support is maintained connected to the inner core tube through the retractable braided cord. When the retractable braided cord is in the release state, the coated support can expand and separate from the inner core tube.

[0011] Furthermore, when the retractable braided cord loop in the bound connection state is pulled open, the portion of the retractable braided cord loop bound to the outside of the film-coated support is sequentially unwound in reverse braiding order: first from the proximal end of the film-coated support to the distal end, and then from the distal end of the film-coated support to the proximal end; when the retractable braided cord loop is partially unwound, the portion of the retractable braided cord loop that has not yet been unwound remains bound to the outside of the film-coated support.

[0012] Furthermore, the pullable braided rope loop is a pullable braided structure in which one or more binding threads are interlocked along the braiding path and all intersections are slip knots.

[0013] Furthermore, the covered scaffold includes a skeleton and a covering;

[0014] The membrane covers the entire skeleton, and the inner and / or outer surfaces of the membrane are further coated with an anticoagulant coating; the skeleton is coated with an antiproliferative drug coating; or,

[0015] The membrane covers only the middle part of the skeleton. The middle part of the skeleton covered by the membrane is the skeleton membrane segment, and the two ends of the skeleton not covered by the membrane are the bare stent segments. The inner and / or outer surfaces of the membrane also have an anticoagulant coating, and the bare stent segments or all parts of the skeleton are coated with antiproliferative drugs.

[0016] Furthermore, the covered support in the unfolded state is a tubular structure with the same diameter in each segment; when the covered support is in the torsional retraction state, the density of the binding wires on the outer periphery of each segment of the covered support is the same in the axial direction of the covered support.

[0017] Furthermore, the membrane-covered support in the unfolded state is a variable-diameter tubular structure with at least a local section having a gradually changing diameter; when the membrane-covered support is in the torsional retraction state, in the axial direction of the membrane-covered support, the density of the binding wires on the outer periphery of the variable-diameter section of the membrane-covered support is greater than the density of the binding wires on the outer periphery of other parts.

[0018] Furthermore, the excess thread after the binding thread is woven into the retractable braided rope loop is a traction tail line. The traction tail line extends to the proximal end of the conveyor, and the proximal end of the traction tail line is connected to an operating handle for pulling the traction tail line in the opposite braiding direction.

[0019] Furthermore, the operating handle includes a handle housing, a first rotating wheel, a second rotating wheel, and a timing belt; the first rotating wheel is rotatably mounted on the handle housing around a first rotating shaft, and a portion of the first rotating wheel is exposed outside the handle housing; the second rotating wheel is rotatably mounted inside the handle housing around a second rotating shaft, the traction tail of the binding thread is wound around the second rotating shaft of the second rotating wheel, and the timing belt is sleeved on the outer periphery of the first rotating wheel and the second rotating wheel; when the first rotating wheel is operated to rotate, the first rotating wheel drives the second rotating wheel to rotate through the timing belt, thereby driving the binding thread to wind around the second rotating shaft of the second rotating wheel.

[0020] Furthermore, the operating handle also includes a stop installed inside the handle housing, the stop engaging with the gear teeth on the second rotating wheel to restrict the second rotating wheel from rotating in the opposite direction.

[0021] Furthermore, the conveyor also includes a double-lumen tube fixedly connected to the proximal end of the inner core tube, the proximal end of the double-lumen tube passing through the operating handle; the double-lumen tube has a guide wire cavity and a binding wire cavity inside, the guide wire cavity of the double-lumen tube is connected to the guide wire cavity inside the inner core tube, the binding wire cavity is for the binding wire to pass through, the distal end of the binding wire cavity has a binding wire inlet, the proximal end of the binding wire cavity has a binding wire outlet, the binding wire outlet is located inside the operating handle, the traction tail wire of the binding wire passes through the binding wire cavity and extends into the interior of the operating handle; the portion of the double-lumen tube extending out of the operating handle is fixed with a double-lumen tube connector.

[0022] The technical solution of this invention has the following advantages: the covered stent twists and rotates before being bound to the outer periphery of the inner core tube with a ligature. The covered stent is released by pulling the ligature. Compared with the existing technology where the covered stent is placed inside the outer sheath and released by retracting the outer sheath, the delivery device does not require an outer sheath. This not only simplifies the structure and facilitates the release of the covered stent, but also reduces the size of the covered stent after twisting and rotating and being bound with a ligature. This makes the overall diameter of the covered stent and the inner core tube smaller during delivery, which is more conducive to delivery within the blood vessel. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the overall structure of the covered stent system in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the inner core tube and the double-lumen tube in an embodiment of the present invention, as well as a partial cross-sectional view of the double-lumen tube;

[0026] Figure 3 This is a schematic diagram of the structure in an embodiment of the present invention, showing how a retractable braided rope can bind a film-coated support to the outer periphery of an inner core tube.

[0027] Figure 4 This is a schematic diagram of the structure in an embodiment of the present invention, showing the partial untying of the pullable braided rope loop and the partial unfolding of the film-coated support.

[0028] Figure 5 This is a schematic diagram of the structure of the first embodiment of the covered stent in this invention;

[0029] Figure 6 This is a schematic diagram of the structure of a second embodiment of the covered stent in this invention;

[0030] Figure 7 This is a schematic diagram of the third embodiment of the covered stent in the present invention;

[0031] Figure 8 This is a schematic diagram of the fourth embodiment of the covered stent in the present invention;

[0032] Figure 9 This is a schematic diagram of the structure of the pullable braided rope loop when the density of the binding threads in each section is different in an embodiment of the present invention;

[0033] Figure 10 This is a schematic diagram of the overall operation handle in an embodiment of the present invention;

[0034] Figure 11 This is a schematic diagram of the internal structure of the operating handle in an embodiment of the present invention.

[0035] Explanation of reference numerals in the attached drawings: 110, inner core tube; 120, double-lumen tube; 121, guide wire cavity; 122, binding wire cavity; 122a, binding wire inlet; 122b, binding wire outlet; 130, operating handle; 131, handle housing; 132, first rotating wheel; 133, second rotating wheel; 134, synchronous belt; 135, stop; 140, double-lumen tube connector; 200, film-coated support; 210, tube diameter transition section; 300, retractable braided rope sleeve; 300a, sparse binding wire section; 300b, dense binding wire section; 310, traction tail line. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this application, it should be understood that the terms "proximal" and "distal" throughout refer to near and far relative to the operator. In use, the end closer to the doctor or operator is the "proximal" end, i.e., the end where the operator is located, and the end farther from the doctor or operator is the "distal" end, i.e., the end where the stent is located. The above descriptions of orientation are for ease of description and simplification only, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this application.

[0038] In the description of this application, it should be noted that the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in the invention based on the specific circumstances.

[0039] like Figure 1A covered stent system is shown, comprising a delivery device, a covered stent 200, and a retractable braided cord sheath 300. The delivery device includes an inner core tube 110, a double-lumen tube 120, and an operating handle 130. The distal end of the inner core tube 110 is equipped with a guide head. The distal end of the double-lumen tube 120 is fixedly connected to the proximal end of the inner core tube 110 by means of heat fusion welding, adhesive bonding, etc. The double-lumen tube 120 has a guidewire cavity 121 inside, which communicates with the guidewire cavity inside the inner core tube 110. A double-lumen tube connector 140 is adhesively fixed to the proximal end of the double-lumen tube 120 extending beyond the operating handle 130. The double-lumen tube connector 140 is used to connect a syringe; before surgery, the syringe can be injected with disinfectant to disinfect the double-lumen tube 120 and the guidewire cavity inside the inner core tube 110. The film-coated stent 200 is a self-expanding structure sleeved on the outer periphery of the distal end of the inner core tube 110; the film-coated stent 200 has a torsional retraction state in which it is twisted at a certain angle around its own axis and bound by the retractable braided rope sleeve 300, and an unfolded state in which it returns to its pre-twist shape and unfolds radially outward after the binding of the retractable braided rope sleeve 300 is released.

[0040] like Figure 1 and Figure 2 As shown, the interior of the dual-lumen tube 120 also includes a binding cavity 122 for the binding thread to pass through. The binding cavity 122 and the guide wire cavity 121 are two independent channels within the dual-lumen tube 120. The distal end of the binding cavity 122 has a binding inlet 122a, and the proximal end has a binding outlet 122b. The binding outlet 122b is located inside the operating handle 130, and the binding thread passes through the binding cavity 122 and extends into the operating handle 130.

[0041] like Figure 2 , Figure 3 and Figure 4As shown, the retractable braided rope loop 300 is a retractable braided structure in which one or more binding threads are interlocked along the braiding path, and all intersections are slip knots. The excess binding thread after weaving the retractable braided rope loop 300 is defined as the traction tail thread 310. The traction tail thread 310 extends into the binding cavity 122 of the double-lumen tube 120 through the binding thread inlet 122a, and then extends out from the binding thread outlet 122b of the binding cavity 122. The proximal end of the traction tail thread 310 is connected to the operating handle 130 at the proximal end of the conveyor. The operating handle 130 is used to pull the traction tail thread 310 in the reverse braiding direction of the retractable braided rope loop 300. The retractable braided rope loop 300 has a bound connection state where multiple slip knots are woven and bound to the outer periphery of the inner core tube 110 and the membrane support 200 in a twisted and retracted state, and a released state where it is pulled apart into binding thread under external force, releasing the binding of the membrane support 200. When the retractable braided cord 300 is in a bound connection state, the film-coated support 200 is maintained connected to the inner core tube 110 through the retractable braided cord 300; when the retractable braided cord 300 is in a released state, the film-coated support 200 can expand and separate from the inner core tube 110.

[0042] In this design, the braided loop 300 is woven from the proximal end of the covered bracket 200 to the distal end, and then back from the distal end to the proximal end. This results in the covered bracket 200 being covered by double layers of binding wire. When the covered bracket 200 is released, the binding wire first detaches from the proximal end to the distal end, and then back again. Compared to a single layer of binding wire woven from proximal to distal end to form the removable loop 300, even if the removable loop 300 is pulled apart by a small length, the covered bracket 200 will not be released, thus reducing the probability of accidental release.

[0043] Specifically, all the braided intersections of the pull-out braided rope loop 300 are locked by the mutual pressure of the binding threads and the braiding path. During the weaving process, the binding threads of the pull-out braided rope loop 300 are arranged around the film-coated support 200 in a series of repeating, symmetrical figure-eight or U-shaped loops that intersect and hook each other. Each newly woven loop in the binding thread presses on a specific part of the previous loop and is also pressed down by the next loop, forming a mechanical balance. Once the traction tail line 310 of the binding thread is pulled, this tension will be quickly transmitted along the preset braiding path, unlocking each locking point in turn, thereby realizing the disassembly of the pull-out braided rope loop 300.

[0044] like Figure 2 and Figure 3As shown, the outer diameter of the double-lumen tube 120 is larger than the outer diameter of the inner core tube 110. The end faces of the double-lumen tube 120 and the inner core tube 110 connected form a limiting step. The limiting step can provide support for the proximal end of the covered stent 200. When the retractable braided rope loop 300 is pulled to release the covered stent 200, the limiting step can prevent the covered stent 200 from sliding, so that the covered stent 200 can be released in place at the preset position, thereby improving the accuracy of the release position of the covered stent 200.

[0045] During the assembly of the covered stent 200, the covered stent 200 twists and rotates on its own and is then bound to the outer periphery of the inner core tube 110 with a ligature. The covered stent 200 is then transported along with the inner core tube 110 of the delivery device. Compared with the existing technology where the untwisted covered stent 200 is placed inside the outer sheath of the delivery device, this method eliminates the need for an additional outer sheath around the twisted covered stent 200, resulting in a simpler structure and easier release of the covered stent 200. Furthermore, the diameter of the self-twisted covered stent 200 is smaller, and the elimination of the outer sheath further reduces the overall diameter of the covered stent 200 and the inner core tube 110 during delivery, making it more conducive to delivery within the blood vessel.

[0046] During the release of the covered stent 200, the inner core tube 110 of the delivery device can deliver the covered stent 200 to the predetermined site through the vascular access. By operating the handle 130, the traction tail line 310 is pulled in the reverse braiding direction of the retractable braided rope 300. The part of the retractable braided rope 300 bound to the covered stent 200 is sequentially untied into a binding thread in the reverse braiding sequence, first from the proximal end of the covered stent 200 to the distal end of the covered stent 200, and then from the distal end of the covered stent 200 to the proximal end of the covered stent 200. When the retractable braided cord 300 is partially untied into a binding thread, the untied portion of the film-coated bracket 200 expands and unfolds on its own, while the remaining portion of the film-coated bracket 200 remains bound to the outer periphery of the inner core tube 110 by the untied portion of the retractable braided cord 300. When the retractable braided cord 300 is completely untied into a binding thread, the binding of the film-coated bracket 200 is completely released, and the film-coated bracket 200 expands and unfolds on its own, separating from the inner core tube 110, thus completing the release of the film-coated bracket 200.

[0047] In this covered stent system, the covered stent 200 twists and rotates before being secured to the outer periphery of the inner core tube 110 by a retractable braided loop 300. The covered stent 200 is released by pulling out the retractable braided loop 300. Compared with the existing technology where the covered stent 200 is placed inside the outer sheath and released by retracting the outer sheath, the covered stent 200 after twisting is smaller in size. This allows the overall diameter of the covered stent 200 and the inner core tube 110 to be smaller during delivery, which is more conducive to delivery in blood vessels.

[0048] The membrane covers the entire skeleton, and the inner and / or outer surfaces of the membrane are further coated with an anticoagulant coating; or, the membrane covers only the middle part of the skeleton, the middle part of the skeleton covered by the membrane is the skeleton membrane segment, and the two ends of the skeleton not covered by the membrane are the bare stent segments; the inner and / or outer surfaces of the membrane are further coated with an anticoagulant coating, and the bare stent segments or all parts of the skeleton are coated with an antiproliferative drug coating.

[0049] like Figure 5 As shown, in a first embodiment of the covered stent 200, the covered stent 200 includes a skeleton and a covering. The covering covers the entire skeleton, and the inner and / or outer surfaces of the covering have an anticoagulant coating. The skeleton is provided with an anti-proliferative drug coating. In its unfolded state, the covered stent 200 is a tubular structure with equal diameters in each segment. Combined with... Figure 2 When the covered stent 200 is in a twisted and retracted state, the density of the peripheral binding sutures of each segment of the covered stent 200 is the same in the axial direction of the covered stent 200. This setting allows the covered stent 200 to better fit blood vessels of the same diameter after it is deployed.

[0050] like Figure 6 As shown, in a second embodiment of the covered stent 200, the covered stent 200 includes a skeleton and a covering. The covering only covers the middle portion of the skeleton; the portion of the skeleton covered by the covering is the skeleton-covered segment, and the portions at both ends of the skeleton not covered by the covering are the bare stent segments. The inner and / or outer surfaces of the covering also have an anticoagulant coating, and the bare stent segments are coated with an anti-proliferative drug coating. In its deployed state, the covered stent 200 is a tubular structure with equal diameters in each segment. Figure 2 When the covered stent 200 is in a twisted and retracted state, the density of the peripheral binding sutures on each segment of the covered stent 200 is the same in the axial direction of the covered stent 200. This setting allows the covered stent 200 to better conform to blood vessels of the same diameter after unfolding, and at the same time, the bare stent segments at both ends of the covered stent 200 can better anchor the covered stent 200 in the blood vessel, preventing the covered stent 200 from shifting.

[0051] like Figure 7 As shown, in a third embodiment of the covered stent 200, the covered stent 200 includes a skeleton and a covering. The covering covers the entire skeleton, and the inner and / or outer surfaces of the covering have an anticoagulant coating. The skeleton is provided with an anti-proliferative drug coating. In its deployed state, the covered stent 200 is a variable-diameter tubular structure with a gradually increasing diameter at one end. The covered stent 200 includes a diameter-gradient section 210 located at one end with a gradually increasing diameter. (Combined with...) Figure 9When the covered stent 200 is in a twisted and retracted state, the retractable braided cord 300 binding the periphery of the covered stent 200 includes a sparsely bound section 300a and a densely bound section 300b arranged sequentially along its own axial direction. The cord density of the densely bound section 300b is greater than that of the sparsely bound section 300a. The densely bound section 300b is bound to the diameter-gradient section 210 of the covered stent 200, while the sparsely bound section 300a is bound to the remaining sections of the covered stent 200. This arrangement allows the covered stent 200 to better conform to the diameter-gradient blood vessel after deployment. Furthermore, since the diameter transition section 210 of the membrane support 200 is larger than the diameter of the rest of the membrane support 200, the radial support force of the diameter transition section 210 is also relatively greater. The densely packed binding section 300b with a larger binding wire distribution density around the diameter transition section 210 makes the outer diameter of the diameter transition section 210 after being bound by the densely packed binding section 300b closer to the outer diameter of the rest of the membrane support 200, thus avoiding the outer diameter of the diameter transition section 210 being too large in the bound connection state and affecting the passage.

[0052] like Figure 8 As shown, in the fourth embodiment of the covered stent 200, the covered stent 200 includes a skeleton and a covering. The covering only covers the middle portion of the skeleton; the portion of the skeleton covered by the covering is the skeleton-covered segment, and the portions at both ends of the skeleton not covered by the covering are the bare stent segments. The inner and / or outer surfaces of the covering also have an anticoagulant coating, and the bare stent segments are coated with an anti-proliferative drug coating. In its deployed state, the covered stent 200 is a variable-diameter tubular structure with a gradually decreasing diameter at one end. (Combined with...) Figure 9 When the covered stent 200 is in a twisted and retracted state, the retractable braided cord 300 binding the periphery of the covered stent 200 includes sparsely bound sections 300a and densely bound sections 300b arranged sequentially along its own axial direction. The density of the binding cords in the densely bound sections 300b is greater than that in the sparsely bound sections 300a. The densely bound sections 300b are bound to the diameter-gradient section 210 of the covered stent 200, while the sparsely bound sections 300a are bound to the remaining sections of the covered stent 200. This arrangement allows the covered stent 200 to conform to the diameter-gradient blood vessel after unfolding, while the bare stent sections at both ends of the covered stent 200 can better anchor the covered stent 200 within the blood vessel, preventing displacement of the covered stent 200. Similarly, since the diameter transition section 210 of the membrane support 200 is larger than the diameter of the rest of the membrane support 200, the radial support force of the diameter transition section 210 is also relatively greater. The outer periphery of the diameter transition section 210 is bound by the densely packed binding section 300b, which has a larger binding density. After being bound by the densely packed binding section 300b, the outer diameter of the diameter transition section 210 is closer to the outer diameter of the rest of the membrane support 200, thus avoiding the outer diameter of the diameter transition section 210 being too large in the bound connection state, which would affect the passage.

[0053] like Figure 10 and Figure 11 As shown, in some embodiments of the operating handle 130, the operating handle 130 includes a handle housing 131, a first rotating wheel 132, a second rotating wheel 133, and a timing belt 134. The handle housing 131 is assembled from a pair of half-housing halves. The first rotating wheel 132 is rotatably mounted on the handle housing 131 about a first axis, with a portion of the first rotating wheel 132 protruding from the outside of the handle housing 131. The second rotating wheel 133 is rotatably mounted inside the handle housing 131 about a second axis, and the traction tail line 310 of the binding thread is wound around the second axis of the second rotating wheel 133. The timing belt 134 is sleeved on the outer periphery of the first rotating wheel 132 and the second rotating wheel 133. When the first rotating wheel 132 is rotated, it drives the second rotating wheel 133 to rotate via the timing belt 134, thereby causing the binding thread to wind around the second axis of the second rotating wheel 133.

[0054] like Figure 10 and Figure 11As shown, the operating handle 130 also includes a stop 135 installed in the handle housing 131. The stop 135 engages with the gear teeth on the second rotating wheel 133 to restrict the second rotating wheel 133 from rotating in the opposite direction. In a first embodiment of the stop 135, the stop 135 is specifically a pawl that can be rotated by external force. When releasing the film-coated bracket 200, the operator rotates the first rotating wheel 132 in the forward direction. The first rotating wheel 132 drives the second rotating wheel 133 to rotate. The individual binding wires of the removable braided rope loop 300 bound on the film-coated bracket 200 are continuously wound onto the rotating shaft of the second rotating wheel 133. This process is dynamic. The binding wires on the film-coated bracket 200 are untied and wound and fixed at the same time, thereby completing the disassembly of the removable braided rope loop 300 on the film-coated bracket 200. The function of the stop 135 is to restrict the second rotating wheel 133 and the first rotating wheel 132 from rotating in opposite directions, so that the untied binding thread is kept as taut as possible, which facilitates control over the length of the untied portion of the pull-out braided rope loop 300. In a second embodiment of the stop 135, the stop 135 can also be a structure with a pawl and a torsion spring (V-shaped). When releasing the film-coated bracket 200, the operator rotates the first rotating wheel 132 forward, which drives the second rotating wheel 133 to rotate. The second rotating wheel 133 lifts the pawl, and the individual binding thread after the pull-out braided rope loop 300 is untied is continuously wound onto the rotating shaft of the second rotating wheel 133, realizing the normal release of the film-coated bracket 200. When the first rotating wheel 132 rotates in the opposite direction, the pawl is lifted by the torsion spring, and the pawl locks the second rotating wheel 133, restricting the second rotating wheel 133 from rotating in the opposite direction. In some other embodiments of the stop 135, the stop 135 may also be a one-way bearing that is coaxially fixedly connected to the second rotating wheel 133. The one-way bearing only allows the second rotating wheel 133 to rotate in the forward direction and has the function of preventing the second rotating wheel 133 from rotating in the reverse direction.

[0055] The covered stent system provided by this invention involves the covered stent 200 twisting and rotating before being secured to the outer periphery of the inner core tube 110 with a ligature. The covered stent 200 is released by pulling the ligature. Compared with the prior art where the covered stent 200 is placed inside the outer sheath and released by retracting the outer sheath, the covered stent 200 is smaller after twisting and does not require an additional outer sheath around the covered stent 200 after twisting. This allows the overall diameter of the covered stent 200 and the inner core tube 110 to be smaller during delivery, which is more conducive to delivery within blood vessels.

[0056] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A covered stent system, characterized by, The application relates to a stent delivery device, comprising: a delivery device, comprising an inner core tube (110); a stent (200), which is a self-expanding structure sleeved on the outer periphery of the inner core tube (110), has a twisted and retracted state twisted by a certain angle with the self-axial direction as the rotation center and is bound by a pullable and untieable braided rope sleeve (300), and has an expanded state expanded radially outward after the binding of the pullable and untieable braided rope sleeve (300) is released; the pullable and untieable braided rope sleeve (300) is a pullable and untieable braided structure in which the binding wires are cross-hooked along a braiding path and all the cross points are active knots, the pullable and untieable braided rope sleeve (300) has a bound connection state in which a plurality of active knots are braided and bound on the outer periphery of the stent (200) in the twisted and retracted state, and a untie and release state in which the binding wires are untied and the binding on the stent (200) is released under the pulling of external force; when the pullable and untieable braided rope sleeve (300) is in the bound connection state, the stent (200) is kept connected with the inner core tube (110) through the pullable and untieable braided rope sleeve (300); when the pullable and untieable braided rope sleeve (300) is in the untie and release state, the stent (200) can be self-expanded and separated from the inner core tube (110); when the pullable and untieable braided rope sleeve (300) in the bound connection state is pulled and untied, the part of the pullable and untieable braided rope sleeve (300) bound outside the stent (200) is untied in a reverse braiding sequence, i.e. from the proximal end of the stent (200) to the distal end of the stent (200) and then from the distal end of the stent (200) to the proximal end of the stent (200); when the pullable and untieable braided rope sleeve (300) is partially untied, the part of the pullable and untieable braided rope sleeve (300) that has not been untied keeps the state of binding the outer periphery of the stent (200).

2. The covered stent system of claim 1, wherein, The pullable and untieable braided rope sleeve (300) is a pullable and untieable braided structure in which one or more binding wires are cross-hooked along a braiding path and all the cross points are active knots.

3. The covered stent system of claim 1, wherein, The stent (200) comprises a framework and a covering film; the covering film covers the entire framework, and the inner surface and / or the outer surface of the covering film has an anticoagulation coating, and the framework is provided with an anti-proliferative drug coating; or, the covering film only covers the middle part of the framework, and the inner surface and / or the outer surface of the covering film has an anticoagulation coating, and the part of the framework not covered by the covering film is provided with an anti-proliferative drug coating.

4. The covered stent system of claim 3, wherein, The stent (200) is an equal-diameter tubular structure with the same pipe diameter of each section in the expanded state; when the stent (200) is in the twisted and retracted state, the tightness of the binding wires on the outer periphery of each section of the stent (200) is the same in the axial direction of the stent (200).

5. The covered stent system of claim 3, wherein, The covered stent (200) is a variable-diameter tubular structure with at least a locally variable-diameter section in the expanded state; when the covered stent (200) is in the twisted and retracted state, the density of the binding wires on the outer periphery of the variable-diameter section (210) of the covered stent (200) is greater than that of other parts in the axial direction of the covered stent (200).

6. The covered stent system of any of claims 1-5, wherein, The remaining part of the binding wire after weaving the pullable and disentangleable rope sleeve (300) is a traction tail wire (310), which extends to the proximal end of the delivery device, and the proximal end of the traction tail wire (310) is connected with an operation handle (130) for pulling the traction tail wire in the reverse weaving direction.

7. The covered stent system of claim 6, wherein, The operation handle (130) comprises a handle shell (131), a first rotating wheel (132), a second rotating wheel (133) and a synchronous belt (134); the first rotating wheel (132) is rotatably mounted on the first rotating shaft of the handle shell (131), and part of the first rotating wheel (132) is exposed outside the handle shell (131); the second rotating wheel (133) is rotatably mounted on the second rotating shaft of the handle shell (131), the traction tail wire (310) of the binding wire is wound around the second rotating shaft of the second rotating wheel (133), and the synchronous belt (134) is sleeved on the outer periphery of the first rotating wheel (132) and the second rotating wheel (133); when the first rotating wheel (132) is operated to rotate, the first rotating wheel (132) drives the second rotating wheel (133) to rotate through the synchronous belt (134), thereby driving the binding wire to be wound around the second rotating shaft of the second rotating wheel (133).

8. The covered stent system of claim 7, wherein, The operation handle (130) further comprises a stopper (135) mounted in the handle shell (131), which cooperates with the gear teeth on the second rotating wheel (133) to limit the reverse rotation of the second rotating wheel (133).

9. The covered stent system of claim 7, wherein, The delivery device further comprises a double-lumen tube (120) fixedly connected with the proximal end of the inner core tube, the proximal end of the double-lumen tube (120) passes through the operation handle (130), the inner part of the double-lumen tube (120) is provided with a guide wire lumen (121) and a binding wire lumen (122), the guide wire lumen (121) of the double-lumen tube (120) communicates with the guide wire lumen in the inner part of the inner core tube (110), the binding wire lumen (122) is for the binding wire to pass through, the distal end of the binding wire lumen (122) is provided with a binding wire inlet (122a), and the proximal end of the binding wire lumen (122) is provided with a binding wire outlet (122b), which is located in the inner part of the operation handle (130); the traction tail wire (310) of the binding wire extends to the inner part of the operation handle (130) through the binding wire lumen (122).

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