Covered stent and conveying method thereof

Abstract

The invention relates to a covered stent and a conveying method thereof. The covered stent is a tubular stent, the peripheral face of the covered stent is provided with a first area and a second area, the second area penetrates through the covered stent in the target direction, and the target direction refers to the direction from the first axial end to the second axial end of the covered stent; the covered stent comprises a stent body and a covering film, the stent body is arranged in the first area, and the covering film is at least arranged in the first area to cover the stent body. The covered stent can be applied to ureters, esophagus and other natural cavities needing wriggling, axial displacement does not occur during wriggling of the natural cavities, granulation can be prevented from growing towards the interior of the covered stent, and then the covered stent can be prevented from being narrowed again; the covered stent can also be applied to natural tracts such as trachea and bronchus, so that fluff on the inner wall of the natural tracts is in contact with foreign matters in the natural tracts in the second area of the covered stent, and the foreign matters in the natural tracts can be discharged.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to a coated stent and a delivery method thereof. Background Art

[0002] Natural cavity stenosis is a common disease, mainly including ureteral stenosis, esophageal stenosis, tracheal and bronchial stenosis. The formation principles of them are similar. Except for congenital stenosis, most natural cavity stenosis is caused by infection, inflammation, trauma or iatrogenic injury, which leads to the formation of scar tissue. The continuous growth of scar tissue leads to the formation of stenosis.

[0003] At present, the most common method for treating natural cavity stenosis is to first dilate the stenosis with a balloon, and then insert a stent or other device to support the stenosis to prevent the occurrence of restenosis. However, when the stent is implanted in the ureter or esophagus, the stent will shift with the peristalsis of the ureter or esophagus, which is not conducive to treatment; when the stent is implanted in the trachea or bronchus, the stent will prevent the contact between the villi on the inner wall of the trachea and bronchus and foreign matter (such as sputum), making it difficult to remove the foreign matter. Summary of the invention

[0004] Based on this, it is necessary to provide a coated stent and a delivery method thereof to address the above-mentioned technical problems.

[0005] A stent graft, the stent graft is a tubular stent, the circumference of the stent graft has a first region and a second region, the second region penetrates the stent graft along a target direction, wherein the target direction refers to a direction from a first axial end to a second axial end of the stent graft;

[0006] The stent graft comprises a stent body and a graft. The stent body is arranged in the first region, and the graft is at least arranged in the first region to cover the stent body.

[0007] The above-mentioned coated stent is applied to natural cavities such as ureters and esophagus that require peristalsis. The stent body will radially contract with the peristalsis of the natural cavity. At this time, since the stent body is not closed in the circumferential direction, it will not extend in the axial direction, that is, the axial length of the stent body remains unchanged, which allows the stent body to be close to the inner wall of the natural cavity, so that it will not shift in the axial direction of the natural cavity; when the natural cavity peristsates, the stent body will also apply appropriate radial support force to the natural cavity to ensure that the natural cavity is expanded while reducing the stimulation to the natural cavity. Among them, the coating on the coated stent is not only covered on the stent body in the first area, but also on the second area, so that the entire coated stent is covered with the coating, so that the lumen of the coated stent is blocked from the inner wall of the natural cavity, which can hinder the growth of granulation tissue into the interior of the coated stent and avoid restenosis in the coated stent.

[0008] When the coated stent is applied to the patient's trachea, bronchus and other natural cavities, since the inner wall of this type of natural cavity has villi for maintaining gas entry and exit and preventing and removing foreign matter, the coating on the coated stent is only covered on the stent body in the first area, but not in the second area, so that the villi on the inner wall of the natural cavity contact the foreign matter in the coated stent in the second area of ​​the coated stent, thereby ensuring the discharge of foreign matter.

[0009] In one embodiment, the extension direction of the second region is not colinear with the axial direction of the stent graft.

[0010] In one embodiment, the second region extends in a spiral shape.

[0011] In one embodiment, the minimum width of the second region is L, and the diameter of the stent graft is D, wherein 0<L≤D / 3.

[0012] In one embodiment, the stent body is woven from wires or cut from tubes.

[0013] In one embodiment, the wire or the tube is a shape memory alloy.

[0014] In one embodiment, the wire material is repeatedly bent in the first region along the axial direction of the stent graft to form the stent body.

[0015] In one embodiment, the wire is in a straight shape and / or a wavy shape.

[0016] In one embodiment, the coating is also arranged in the second region, and the stent body has a natural state and a contracted state. When the stent is in the natural state, the coating fits the circumferential surface formed by the stent body; when the stent is in the contracted state, the coating is sunken into the stent body.

[0017] A method for delivering a coated stent comprises: pressing and gripping the coated stent as described in any one of the above items into a delivery system by winding, and releasing the coated stent from the delivery system after reaching the diseased tissue.

[0018] The above-mentioned coated stent delivery method utilizes the characteristic that the stent body of the coated stent is not closed in the circumferential direction, and compresses the coated stent by winding, so that the diameter of the coated stent is greatly reduced after compressing, thereby reducing the diameter of the sheath tube of the delivery system used to accommodate the coated stent, which can better cooperate with the endoscope to achieve accurate release of the coated stent. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the three-dimensional structure of a coated stent in a contracted state provided in one embodiment of the present application.

[0020] Figure 2 A schematic diagram of the three-dimensional structure of a coated stent in a contracted state provided in another embodiment of the present application.

[0021] Figure 3 A side view of a coated stent in a contracted state provided in another embodiment of the present application.

[0022] Figure 4 A schematic diagram of the structure of a wire material provided in one embodiment of the present application.

[0023] Figure 5 This is a schematic diagram of the structure of a wire material provided in another embodiment of the present application.

[0024] Figure 6 A partially enlarged schematic diagram of a coated stent provided in another embodiment of the present application.

[0025] The reference numerals in the accompanying drawings are described as follows:

[0026] 10. Coated stent; 10a. First region; 10b. Second region; 100. Stent body; 110. Wire material; 200. Coating. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth 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 violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0028] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply 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 on the present application.

[0029] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0030] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0031] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0032] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0033] like Figure 1 and Figure 2As shown, an embodiment of the present application provides a coated stent 10, which is a tubular stent, and the circumferential surface of the coated stent 10 has a first area 10a and a second area 10b, and the second area 10b penetrates the coated stent 10 along a target direction, wherein the target direction refers to the direction from the first axial end to the second axial end of the coated stent 10; the coated stent 10 includes a stent body 100 and a coating 200, the stent body 100 is arranged in the first area 10a, and the coating 200 is at least arranged in the first area 10a to cover the stent body 100.

[0034] It should be noted that, compared to the conventional stent graft 10, the stent graft 10 of the present application is not entirely provided with the stent body 100 on its circumference, only the first region 10a is provided with the stent body 100, and the second region 10b is not provided with the stent body 100. Since the second region 10b runs through the entire stent graft 10 in the direction from the first axial end to the second axial end of the stent graft 10, the stent body 100 is not closed in the circumferential direction, but has an opening.

[0035] The above-mentioned coated stent 10 can be applied to the patient's ureter, esophagus and other natural cavities that require peristalsis to treat ureteral stenosis, esophageal stenosis, etc. It can also be applied to the patient's trachea, bronchus and other natural cavities to treat tracheal, bronchial stenosis, etc.

[0036] When the coated stent 10 is used in natural cavities such as the ureter and esophagus that require peristalsis, the stent body 100 will radially contract with the peristalsis of the natural cavity. At this time, since the stent body 100 is not closed in the circumferential direction, it will not extend in the axial direction, that is, the axial length of the stent body 100 remains unchanged, which allows the stent body 100 to fit tightly against the inner wall of the natural cavity, thereby not shifting in the axial direction of the natural cavity. In addition, when the natural cavity peristalses, the stent body 100 will also apply appropriate radial supporting force to the natural cavity to ensure that the natural cavity is expanded while reducing stimulation to the natural cavity.

[0037] It should be noted that when the natural cavity peristalsis, it will be stimulated by the stent graft 10 to produce granulation tissue, which can cause restenosis in the stent graft 10. In this regard, the coating 200 on the stent graft 10 is not only covered on the stent body 100 in the first area 10a, but also can be Figure 1 As shown, the second area 10b is covered so that the entire coated stent 10 is covered with the coating 200, so that the lumen of the coated stent 10 is blocked from the inner wall of the natural cavity, which can hinder the growth of granulation tissue into the interior of the coated stent 10 and avoid restenosis in the coated stent 10.

[0038] In this application scenario, the shape of the coating 200 is mainly related to whether the stent body 100 is shrunk. Specifically, the stent body 100 has a natural state and a Figure 1 In the contracted state shown, when the stent is in the natural state, the coating 200 adheres to the peripheral surface formed by the stent body 100; when the stent is in the contracted state, the coating 200 is sunken into the stent body 100. It should be noted that Figure 1 The two dotted lines in represent the boundaries of the indentation of the coating 200. The following takes the ureter as an example to describe the flow process of urine: when urine flows to the ureter adjacent to the upstream of the coated stent 10, the ureter in this section begins to peristalsis. At this time, the coated stent 10 is in a natural state and the coating 200 is stretched open, so that all urine can be smoothly squeezed into the lumen of the coated stent 10; then, the coated stent 10 radially contracts with the peristalsis of the ureter in which it is located, thereby squeezing the urine into the downstream ureter. It can be seen that the present application can ensure the normal transportation of urine in the ureter by setting the shape of the coating 200 in this way.

[0039] When the stent graft 10 is applied to a patient's trachea, bronchus or other natural cavity, since the inner wall of such natural cavity has villi for maintaining gas in and out and defending and removing foreign matter, the coating 200 on the stent graft 10 is only covered on the stent body 100 in the first area 10a. Figure 2 As shown, the second region 10b is not covered, so that the villi on the inner wall of the natural cavity come into contact with the foreign matter in the natural cavity at the second region 10b of the stent graft 10, thereby ensuring the discharge of the foreign matter.

[0040] In some embodiments of the present application, the extension direction of the second region 10b is not colinear with the axial direction of the stent graft 10. In this way, by setting the extension direction of the second region 10b, the stent graft 10 can provide uniform radial support force to the natural cavity, avoiding stimulation of the inner wall of the natural cavity due to uneven force during peristalsis.

[0041] The second region 10b may be arranged to be inclined relative to the central axis of the stent graft 10, or may be arranged to be inclined relative to the central axis of the stent graft 10. Figure 1 and Figure 2 As shown, the spiral second region 10b extends in a spiral shape. Considering that the spiral second region 10b can enable the stent graft 10 to provide uniform radial support force to the natural cavity in all directions, it can be preferably adopted.

[0042] like Figure 3 As shown, in some embodiments of the present application, the minimum width of the second region 10b is L, and the diameter of the stent graft 10 is D, where 0<L≤D / 3. Such a configuration can ensure that the stent graft 10 can provide a reasonable radial support force to the natural cavity to reduce the stimulation to the natural cavity, and can also effectively shrink with the peristalsis of the natural cavity to ensure that the stent graft 10 can be closely attached to the inner wall of the natural cavity when the natural cavity peristsates.

[0043] like Figure 4 and Figure 5 As shown, in some embodiments of the present application, the stent body 100 can be woven from a wire 110. The wire 110 can be a shape memory alloy, such as a nickel-titanium alloy. The stent body 100 woven from the wire 110 can be restored to its original shape when the natural cavity does not creep, thereby effectively supporting the lesion of the natural cavity. It should be noted that the original shape of the stent body 100 refers to the shape in the natural state (i.e., without external force).

[0044] In a specific implementation, the wire 110 can be wound around a mold for weaving, and then subjected to heating, cooling and other processes, and finally shaped to obtain the stent body 100 of the above structure. Of course, the wire 110 can be woven into a planar structure first, and then obtained by winding and shaping.

[0045] Regarding the diameter of the wire 110, the present application does not impose any specific restrictions, as long as the coated stent 10 can provide reasonable radial support to the natural cavity and can closely adhere to the inner wall of the natural cavity when the natural cavity moves. For example, the diameter of the wire 110 can be 0.4 mm to 2.4 mm.

[0046] Further, see Figure 1 and Figure 2 The wire 110 is repeatedly bent in the first region 10a along the axial direction of the stent graft 10 to form the stent body 100. The weaving method of the wire 110 is not only simple, but also ensures that the stent graft 10 can provide reasonable radial support force to the natural cavity to reduce stimulation to the natural cavity.

[0047] Among them, the wire 110 can be Figure 4 If the stent body 100 woven from the straight-shaped wire material 110 does not provide enough radial support to the natural cavity, you can choose Figure 5 and Figure 6 The wavy wire 110 shown is woven. Figure 5 The peak height H and the distance between peaks M of the wavy wire 110 can be determined according to the radial support strength of the stent body 100 to the natural cavity. The greater the required radial support strength, the greater the peak height H of the wavy wire 110 and the smaller the distance between peaks M.

[0048] It should be noted that the stent body 100 can also be formed by weaving together a straight-line wire material 110 and a wavy wire material 110 .

[0049] Of course, in other embodiments, the stent body 100 can also be cut from a tube. The tube can be a shape memory alloy, such as a nickel-titanium alloy. The stent body 100 cut from the tube can return to its original shape when the natural cavity does not creep, thereby effectively supporting the lesion of the natural cavity.

[0050] In a specific implementation, the tube may be cut first, and then subjected to heat setting, polishing and other processes, to finally obtain the bracket body 100 of the above structure.

[0051] In some embodiments of the present application, the material of the coating 200 includes at least one of polyurethane, silicone and epoxy resin, and the coating 200 can be applied to the inner surface and / or outer surface of the bracket body 100 by dipping, manual coating, spraying, etc.

[0052] On the other hand, an embodiment of the present application also provides a method for conveying the coated stent 10 as described above, the method comprising: pressing the coated stent 10 into the conveying system by winding, and releasing the coated stent 10 from the conveying system after reaching the diseased tissue.

[0053] It should be noted that, compared to the conventional stent graft 10, the stent graft 10 of the present application is not entirely provided with the stent body 100 on its circumference, only the first region 10a is provided with the stent body 100, and the second region 10b is not provided with the stent body 100. Since the second region 10b runs through the entire stent graft 10 in the direction from the first axial end to the second axial end of the stent graft 10, the stent body 100 is not closed in the circumferential direction, but has an opening.

[0054] The coated stent 10 can be applied to natural cavities such as the ureter and esophagus that require peristalsis. It does not cause axial displacement during peristalsis of the natural cavity and can also hinder the growth of granulation tissue into the interior of the coated stent 10, thereby avoiding re-stenosis of the coated stent 10. It can also be applied to natural cavities such as the trachea and bronchi, so that the villi on the inner wall of the natural cavity contact with foreign matter in the natural cavity in the second area 10b of the coated stent 10, thereby ensuring the discharge of foreign matter in the natural cavity.

[0055] This delivery method utilizes the characteristic that the stent body 100 of the coated stent 10 is not closed in the circumferential direction, and compresses the coated stent 10 in a winding manner, so that the diameter of the coated stent 10 is greatly reduced after compressing, thereby reducing the sheath diameter of the delivery system used to accommodate the coated stent 10, which can better cooperate with the endoscope to achieve the precise release of the coated stent 10.

[0056] Among them, there are two main ways of cooperation between the delivery system and the endoscope. The first is that the delivery system and the endoscope share a passage in the patient's body. Since the sheath diameter of the delivery system is small, the sheath of the delivery system can be placed in the passage and the coated stent 10 can be delivered to the lesion site without withdrawing the endoscope from the passage, and then the coated stent 10 can be released under the direct vision of the endoscope; the second is to directly open a working channel on the endoscope for the sheath of the delivery system to pass through. Since the sheath diameter of the delivery system is small, it can easily pass through the working channel of the endoscope to reach the lesion site for release, thereby supporting the lesion site.

[0057] In order to describe the structure of the stent graft 10 applied in different natural cavities, two embodiments are given below.

[0058] Example 1

[0059] See also Figure 1 This embodiment provides a stent graft 10, which is applied to natural cavities such as ureters and esophagus that require peristalsis. Specifically, the stent graft 10 is a tubular stent, and the circumferential surface of the stent graft 10 has a first region 10a and a second region 10b, and the second region 10b penetrates the stent graft 10 along a target direction, wherein the target direction refers to the direction from the first axial end to the second axial end of the stent graft 10; the stent graft 10 includes a stent body 100 and a coating 200, the stent body 100 is arranged in the first region 10a, and the coating 200 is arranged in the first region 10a and the second region 10b.

[0060] In this embodiment, the second region 10b is as follows Figure 1 Shown extending in a spiral shape.

[0061] In this embodiment, the minimum width of the second region 10b is L, and the diameter of the stent graft 10 is D, wherein 0<L≤D / 3.

[0062] In this embodiment, the stent body 100 is woven from wires 110. The wires 110 may be a shape memory alloy, such as a nickel-titanium alloy. Specifically, the wires 110 may be wound around a mold for weaving, and then subjected to heating, cooling and other processes, and finally shaped to obtain the stent body 100 of the above structure.

[0063] See also Figure 1 The wire 110 is repeatedly bent in the first region 10a along the axial direction of the stent graft 10 to form the stent body 100. The wire 110 may be Figure 4 The one-character type shown.

[0064] In this embodiment, the material of the coating 200 includes at least one of polyurethane, silicone and epoxy resin, and the coating 200 can be applied to the inner surface and / or outer surface of the stent body 100 by dipping, manual coating, spraying, etc.

[0065] Example 2

[0066] See also Figure 2 and Figure 3 This embodiment provides a stent graft 10, which is applied to natural cavities such as trachea and bronchus. Specifically, the stent graft 10 is a tubular stent, and the circumferential surface of the stent graft 10 has a first region 10a and a second region 10b, and the second region 10b penetrates the stent graft 10 along a target direction, wherein the target direction refers to the direction from the first axial end to the second axial end of the stent graft 10; the stent graft 10 includes a stent body 100 and a coating 200, the stent body 100 is arranged in the first region 10a, and the coating 200 is arranged in the first region 10a.

[0067] In this embodiment, the second region 10b may extend in a spiral shape.

[0068] In this embodiment, if Figure 3 As shown, the minimum width of the second region 10b is L, and the diameter of the stent graft 10 is D, wherein 0<L≤D / 3.

[0069] In this embodiment, the stent body 100 may be woven from wires 110. The wires 110 may be a shape memory alloy, such as nickel-titanium alloy.

[0070] In a specific implementation, the wire material 110 can be wound onto a mold for weaving, and then subjected to processes such as heating and cooling to finally be shaped to obtain the stent body 100 of the above structure.

[0071] See also Figure 2 The wire 110 is repeatedly bent in the first region 10a along the axial direction of the stent graft 10 to form the stent body 100 .

[0072] Among them, the wire 110 can be Figure 4 The one-character type shown.

[0073] In this embodiment, the material of the coating 200 includes at least one of polyurethane, silicone and epoxy resin, and the coating 200 can be applied to the inner surface and / or outer surface of the stent body 100 by dipping, manual coating, spraying, etc.

[0074] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A stent graft, It is characterized in that The stent graft is a tubular stent, and the circumferential surface of the stent graft has a first region and a second region, and the second region penetrates the stent graft along a target direction, wherein the target direction refers to a direction from a first axial end to a second axial end of the stent graft; The stent graft comprises a stent body and a graft. The stent body is arranged in the first region, and the graft is at least arranged in the first region to cover the stent body.

2. The stent graft according to claim 1, It is characterized in that An extension direction of the second region is not colinear with an axial direction of the stent graft.

3. The stent graft according to claim 2, It is characterized in that The second region extends in a spiral shape.

4. The stent graft according to claim 1, It is characterized in that The minimum width of the second region is L, and the diameter of the stent graft is D, wherein 0<L≤D / 3.

5. The stent graft according to any one of claims 1 to 4, It is characterized in that The stent body is woven from wires or cut from tubes.

6. The stent graft according to claim 5, It is characterized in that The wire material or the tube material is a shape memory alloy.

7. The stent graft according to claim 5, It is characterized in that The wire material is repeatedly bent in the first region along the axial direction of the stent graft to form the stent body.

8. The stent graft according to claim 7, It is characterized in that The wire material is in a straight shape and / or a wavy shape.

9. The stent graft according to any one of claims 1 to 4, It is characterized in that The coating is also arranged in the second area, and the stent body has a natural state and a contracted state. When the stent is in the natural state, the coating adheres to the peripheral surface formed by the stent; when the stent is in the contracted state, the coating is sunken into the stent body.

10. A method for delivering a stent graft, It is characterized in that include: The coated stent as described in any one of claims 1 to 9 is compressed and gripped into a delivery system by winding, and the coated stent is released from the delivery system after reaching the diseased tissue.

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