Covered stent and release device thereof

Abstract

The utility model provides a covered stent and a release device thereof, and relates to the technical field of medical instruments. The covered stent comprises metal stent rings and a covering film, the multiple metal stent rings are sequentially arranged at intervals and all connected with the covering film, in the initial state, the covering film is in a bent state and is provided with a large bent side and a small bent side, and the distance between every two adjacent metal stent rings on the side of the large bent side is larger than the distance between every two adjacent metal stent rings on the side of the small bent side. The covering film can be reversely folded so that the large bent side can be converted into the small bent side, the covering film located on the side can be stacked, meanwhile, the small bent side can be converted into the large bent side, the covering film located on the side can be straightened, and under the structure, the displacement amount of the covered stent in the axial direction can be reduced, and the covering film can be folded in the reverse direction. According to the covered stent, the contact area of the metal stent ring and the inner surface of a blood vessel is guaranteed, so that the covered stent is prevented from being axially shortened after being implanted, meanwhile, the bent structure of the covered stent can guarantee that the covered stent has good adherence to the aortic arch, and the probability of adverse events such as internal leakage is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to a covered stent and a releasing device thereof. Background Technique

[0002] In recent years, with the continuous development of endovascular interventional surgery, thoracic endovascular aortic repair (TEVAR) has been increasingly applied to the clinical treatment of aortic aneurysms and aortic dissections due to its advantages such as safety, minimally invasive, and rapid recovery.

[0003] An aortic aneurysm usually occurs in a part of the blood vessel where the strength or elasticity of the blood vessel wall is insufficient, resulting in abnormal expansion or stretching of the blood vessel wall when blood passes through. It is more common in the abdominal aorta and thoracic aorta, while aortic dissection is more common in the thoracic aorta. The etiology may be related to the patient's age, underlying medical history, genetic predisposition, etc.

[0004] If an aortic aneurysm is not treated, it may cause the blood vessel wall to continuously expand and rupture, leading to death; if aortic dissection is not intervened, the intima of the blood vessel may continuously tear, and the false lumen formed by the blood flow may block other branch blood vessels, thereby causing organ ischemia and failure in these parts, endangering the life and health of the patient.

[0005] In order to inhibit the continuous tearing of aortic dissection and prevent the rupture of aneurysms, current clinical treatment methods mostly adopt interventional surgical methods. Usually, a covered stent is placed at the diseased position through an interventional method using a delivery system to achieve the effect of closing the false lumen or aneurysm cavity. The covered stent can ensure that blood flows through the cavity formed by the covered stent. The covered stent can provide radial support force to ensure the fit between the blood vessel wall and the stent, and provide axial anti-displacement ability. The blood flowing through the blood vessel can be guided by the inner cavity surface of the covered stent to reduce the stress on the blood vessel wall at the aneurysm sac position, reduce the risk of rupture of the blood vessel wall at the aneurysm site, prevent blood from entering the aortic dissection, and guide the blood to continuously enter the blood vessels in other parts through the lumen in the stent.

[0006] Another method for treating aneurysms and aortic dissections is surgical operation. Using an open surgical operation, the diseased part is resected and an artificial blood vessel is implanted to replace the diseased blood vessel, and blood flow passes through the lumen established by the artificial blood vessel to achieve the treatment effect.

[0007] The applicant has found that there are at least the following technical problems in the prior art:

[0008] The interventional treatment process for aneurysms and aortic dissections usually involves compressing a covered stent into a sheath. After establishing a passage at the peripheral artery site, the covered stent is delivered to the lesion location and then released to achieve the therapeutic effect. Currently, most of the covered stent structures on the market are designed in a straight shape. Due to the relatively complex structure and shape of the aortic blood vessel, the straight stent may generate a straightening force after release, resulting in poor wall apposition, and the proximal end is prone to the "beak" phenomenon, which may further cause complications such as endoleak. In addition, the stent is usually released by withdrawing the sheath, which may cause problems such as inaccurate positioning and poor shape after release during the sheath withdrawal process. At the same time, due to the large diameter of the sheath, the invasiveness to the blood vessel is relatively large.

[0009] The surgical method usually involves implanting a prosthetic blood vessel at the lesion site. Although this treatment method can well establish a blood flow channel and to a certain extent retain the biomechanical characteristics of the blood vessel, the surgical operation leaves a large open wound on the patient's body, and the prognosis and recovery require a long time, with a long hospital stay. It is not suitable for every patient, especially for patients with underlying medical histories (such as hypertension, diabetes, heart disease, etc.). The surgical risk is high, and a series of complications such as wound infection may occur after the operation. Summary of the Invention

[0010] The purpose of the present utility model is to provide a covered stent and its release device to solve the technical problems existing in the prior art, where most of the covered stent structures are designed in a straight shape. After release, the straight stent may generate a straightening force, resulting in poor wall apposition, and the proximal end is prone to the "beak" phenomenon, and the covered stent is prone to axial shortening after release. The many technical effects that can be produced by the preferred technical solutions provided by the present utility model are described in detail below.

[0011] To achieve the above purpose, the present utility model provides the following technical solutions:

[0012] A covered stent includes a metal stent ring and a covering film. A plurality of the metal stent rings are arranged at intervals in sequence and are all connected to the covering film. In the initial state, the covering film is in a bent state and has a large bend side and a small bend side. The distance between two adjacent metal stent rings on the large bend side is greater than the distance on the small bend side. The covering film can be reversely folded so that the large bend side is transformed into the small bend side and the covering film on this side generates stacking, while the small bend side is transformed into the large bend side and the covering film on this side becomes straightened.

[0013] Preferably, the covering film can be bent and deformed at the lesion location and then maintain its shape to adapt to the shape of the lesion location.

[0014] Preferably, the metal stent ring is made of nitinol wire material.

[0015] Preferably, the wire diameter of the metal stent ring ranges from 0.3 mm to 0.6 mm.

[0016] Preferably, the film forms continuous horizontal segments, curved segments, and vertical segments at the lesion site, and the bending radius of the center line of the curved segment ranges from 40 mm to 60 mm.

[0017] Preferably, the metal stent ring is sewn and connected to the film.

[0018] Preferably, the metal stent ring is connected to the film by hot pressing and forming.

[0019] A release device for a covered stent, comprising a tip soft head, a head end fixing member, a core tube, a tail end fixing tube, and the above-mentioned covered stent. The head end fixing member is connected to the tip soft head. The proximal end of the core tube is connected to the head end fixing member and its distal end passes through the inside of the tail end fixing tube. The covered stent is sleeved outside the core tube. The proximal end of the covered stent is connected to the head end fixing member and its distal end passes through the inside of the tail end fixing tube.

[0020] Preferably, it further comprises a central core tube and a delivery guide wire. The central core tube passes through the inside of the core tube. The proximal end of the central core tube is connected to the tip soft head. The delivery guide wire passes through the inside of the central core tube.

[0021] Preferably, it further comprises a delivery sheath tube. The delivery sheath tube is sleeved outside the tip soft head, the covered stent, and the tail end fixing tube.

[0022] The beneficial effects of the present utility model are as follows: In the initial state, the film is in a curved state, and its curved segment has a large bend side and a small bend side. The distance between two adjacent metal stent rings on the large bend side is greater than the distance on the small bend side. Thus, the length of the film on the large bend side between two adjacent metal stent rings is longer, and the length of the film on the small bend side is shorter. At the same time, the film itself has good ductility. Therefore, the film can be reversely folded. After reverse folding, the large bend side is transformed into the small bend side and the film located on this side is stacked, while the small bend side is transformed into the large bend side and the film located on this side becomes straightened.

[0023] During the process of reverse folding of the covered stent, since there is more deformability in the membrane structure between two adjacent metal stent rings on the greater curvature side of the covered stent, during the folding process, the lower part of the proximal metal stent ring at the bending part of the covered stent will be embedded into the upper part of the next adjacent metal stent ring, thus realizing the function of stent stacking. Meanwhile, the lesser curvature side of the covered stent also gradually changes from a curved state to a vertical state, and the stent can be compressed and held in the delivery sheath in this state.

[0024] At the same time, due to the reverse folding design, in the natural state, the original greater curvature side becomes the lesser curvature side after the covered stent is stacked and released, and the original lesser curvature side in the natural state becomes the greater curvature side in the released state. Under this structure, the covered membrane spacing between the two metal stent rings at the bending part is shortened, which can reduce the displacement of the covered stent in the axial direction, ensure the contact area between the metal stent ring and the inner surface of the blood vessel, thereby preventing axial shortening after the covered stent is implanted. At the same time, its curved structure can also ensure good wall apposition at the aortic arch.

[0025] On this basis, the covered stent can fit with the curved section of the aortic arch, effectively improving the wall apposition between the stent and the blood vessel after implantation, reducing the probability of adverse events such as endoleak, especially being able to solve the "bird's beak" effect generated at the proximal end after stent release in interventional treatment, and improving the treatment effect of aortic aneurysm and aortic dissection.

[0026] The covered stent has good bending flexibility and is used in cooperation with the release device. Through endovascular intervention and the operation method of withdrawing the sheath, it is implanted into the lesion site of thoracic aortic aneurysm or thoracic aortic dissection. The postoperative recovery time is short, which can reduce complications and achieve lesion treatment. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention 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 invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 Schematic diagram of the original state of the covered stent in Embodiment 1 of the present invention;

[0029] Figure 2 Schematic diagram of the application state of the covered stent after reverse folding in Embodiment 1 of the present invention;

[0030] Figure 3 Schematic diagram of the folding direction of the covered stent in Embodiment 1 of the present invention;

[0031] Figure 4 Schematic diagram after reverse folding of the covered stent in the first embodiment of the present utility model;

[0032] Figure 5 Structural diagram after stacking of the large curvature side of the covered stent in the first embodiment of the present utility model;

[0033] Figure 6 Structural diagram after the small curvature side of the covered stent in the first embodiment of the present utility model is made vertical;

[0034] Figure 7 Structural diagram of the second embodiment of the present utility model;

[0035] Figure 8 Structural diagram of the covered stent in the second embodiment of the present utility model in a partially released state;

[0036] Figure 9 Structural diagram of the head fixing member in the second embodiment of the present utility model in an unreleased state;

[0037] Figure 10 Structural diagram of the covered stent in the second embodiment of the present utility model in a fully released state;

[0038] In the figure, 11, metal stent ring; 12, covering film;

[0039] 2, tip soft head;

[0040] 3, head fixing member;

[0041] 4, core tube;

[0042] 5, tail fixing tube;

[0043] 6, central core tube;

[0044] 7, delivery guide wire;

[0045] 8, delivery sheath. Specific implementation manners

[0046] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the technical solutions of the present utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts fall within the scope protected by the present utility model.

[0047] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "side", etc. is based on the Figure 1 orientation or positional relationship shown, and it is only for the convenience of describing the present utility model 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 thus should not be construed as a limitation to the present utility model.

[0048] In the description of the present utility model, it should also be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0049] In this patent, the term "proximal end" refers to the side of the device close to the heart end, and the "distal end" refers to the side away from the heart end.

[0050] Embodiment 1

[0051] Referring to Figures 1 to 6 , the present utility model provides a covered stent, including a metal stent ring 11 and a covering film 12. The shape of the metal stent ring 11 is annular, and a plurality of metal stent rings 11 are arranged at intervals in sequence and are all connected to the covering film 12. The covering film 12 connected to the metal stent ring 11 is similar to a cylinder, and the covered stent as a whole presents a thin film tubular member.

[0052] Referring to Figure 1 and Figure 3 , this state is the initial state of the covered stent. In the initial state, the covering film 12 is in a bent state, and its bent section has a large bend side and a small bend side. The distance between two adjacent metal stent rings 11 on the large bend side is greater than the distance on the small bend side. Thus, the length of the covering film on the large bend side between two adjacent metal stent rings 11 is longer, and the length of the covering film on the small bend side is shorter. At the same time, the covering film itself has good ductility;

[0053] Therefore, the covering film 12 can be reversely folded. After reverse folding, referring to Figure 3 and Figure 4 , the large bend side is transformed into the small bend side and causes the covering film 12 located on this side to be stacked, while the small bend side is transformed into the large bend side and causes the covering film 12 located on this side to become straightened.

[0054] Figure 5 and Figure 6 Figure 6 is a schematic diagram of the covered stent in the crimped state. During the process of folding the covered stent in the reverse direction, since there is more deformability in the membrane structure between two adjacent metal stent rings 11 on the large curvature side of the covered stent, during the folding process, the lower part of the proximal metal stent ring 11 at the bending part of the covered stent will be embedded into the upper part of the next adjacent metal stent ring 11, thus realizing the function of stent stacking. And the small curvature side of the covered stent also gradually changes from a curved state to a vertical state, and the stent can be crimped into the delivery sheath 8 in this state.

[0055] At the same time, due to the reverse folding design, in the natural state, the original large curvature side becomes the small curvature side after the covered stent is stacked and released, and the original small curvature side in the natural state becomes the large curvature side in the released state. In this structure, the covered membrane spacing between the two metal stent rings 11 at the bending part is shortened, which can reduce the displacement of the covered stent in the axial direction, ensure the contact area between the metal stent ring 11 and the inner surface of the blood vessel, thereby preventing axial shortening after the covered stent is implanted. At the same time, its curved structure can also ensure good wall attachment at the aortic arch.

[0056] In different use scenarios of the covered stent, due to the different distances between two adjacent metal stent rings 11 at the bending section, the movement range of the covered membrane 12 covering the metal stent ring 11 at this part is also different, so different use states will be presented.

[0057] In this embodiment, the metal stent ring 11 is preferably made of an elastic and shape - memory material, and further preferably made of nitinol wire material. And the wire diameter range of the metal stent ring 11 is preferably between 0.3 mm and 0.6 mm. With such a setting, the metal stent ring 11 can have superelasticity and shape - memory property. Therefore, during the use of the covered stent, the metal stent ring 11 can be compressed radially and can return to its original state;

[0058] The body of the metal stent ring 11 can be made by heat - treatment shaping with the cooperation of tooling during production and then connected to the covered membrane 12.

[0059] With the assistance of several metal stent rings 11, the membrane 12 can be bent and deformed at the lesion site and then remain shaped, presenting a natural curved shape, so that the membrane stent can adapt to the shape of the lesion site. The metal stent ring 11 made of superelastic metal material also enables the membrane stent to have the ability to bend and deform and the ability to remain shaped after bending and deforming. On this basis, the membrane stent can fit the curved section of the aortic arch, effectively improving the wall attachment between the stent and the blood vessel after implantation and reducing the probability of adverse events such as endoleak. In particular, it can solve the "beak" effect generated at the proximal end after the stent is released during interventional treatment.

[0060] According to actual usage needs, the membrane 12 can form a continuous three-section design at the lesion site, namely a horizontal section, a curved section, and a vertical section. The bending radius range of the center line of the curved section is between 40 mm and 60 mm. Setting within this data range can better fit the anatomical characteristics of the thoracic aorta, thereby increasing the wall attachment of the membrane 12;

[0061] In this embodiment, the membrane 12 can be made of fluoropolymers including but not limited to expanded polytetrafluoroethylene (e-PTFE), polyester, polyurethane, perfluoroelastomer, etc., polytetrafluoroethylene, silicone, urethane, ultra-high molecular weight polyethylene, aramid fiber, and combinations thereof;

[0062] When the membrane 12 is made of a thin film material formed by polyester or polyurethane, etc., the metal stent ring 11 and the membrane 12 can be stitched and connected together by wires such as nylon wires through surgical operations to form a whole;

[0063] When the membrane 12 is made of a thin film material formed by e-PTFE, PTFE, etc., the metal stent ring 11 and the membrane 12 can be connected together by hot pressing to form a whole;

[0064] In addition to the above connection forms, other connection methods can also be adopted between the metal stent ring 11 and the membrane 12.

[0065] Embodiment 2

[0066] Referring to Figures 7 - 10 , the present invention also provides a release device for a membrane stent, including a tip soft head 2, a head end fixing member 3, a core tube 4, a tail end fixing tube 5, a central core tube 6, a delivery guide wire 7, a delivery sheath tube 8, and the above membrane stent;

[0067] The head end fixing member 3 is connected to the tip soft head 2. The proximal end of the core tube 4 is connected to the head end fixing member 3 and its distal end passes through the inside of the tail end fixing tube 5. The membrane stent is sleeved outside the core tube 4. The proximal end of the membrane stent is connected to the head end fixing member 3 and its distal end passes through the inside of the tail end fixing tube 5;

[0068] The central core tube 6 passes through the inside of the core tube 4. The proximal end of the central core tube 6 is connected to the tip soft head 2. The delivery guide wire 7 passes through the inside of the central core tube 6. The delivery guide wire 7 can be used to enter the aorta or cross tortuous, calcified, and stenotic lesions to reach the target to establish a delivery track.

[0069] The delivery sheath 8 is sleeved outside the tip soft head 2, the covered stent, and the tail end fixing tube 5. The delivery sheath 8 is used to compress the covered stent and implant the covered stent into the lesion site at the same time.

[0070] The tip soft head 2 can be adapted to the delivery guide wire 7, so that the delivery system has better passability;

[0071] The proximal end of the covered stent can preferably be fixed to the head end fixing member 3 in the form of a hook. After the distal end of the covered stent is completely released, the head end fixing member 3 is disengaged, so as to realize the operation of distributing and releasing the covered stent;

[0072] After the covered stent is assembled into the delivery sheath 8, the proximal end of the tail end fixing tube 5 plays a limiting role on the distal end of the covered stent, so that the covered stent can not slide inside the delivery sheath 8. At the same time, the hardness of the tail end fixing tube 5 preferably shows an increasing trend from the proximal end to the distal end.

[0073] The usage method of the release device mentioned in this embodiment is as follows: First, the covered stent is assembled into the delivery sheath 8 with a suitable size by means of press-gripping. After assembly, the proximal end of the covered stent is clamped and fixed by the head end fixing member 3, and the distal end is restricted by the limit of the tail end fixing tube 5, so as to realize the fixation of the covered stent in the sheath;

[0074] After the assembly is completed, the whole delivery system is advanced along the delivery guide wire 7 to deliver the covered stent to the lesion site. After positioning, the stent is started to be released;

[0075] Retreat the delivery sheath 8 towards the distal end to release the distal stent ring of the covered stent. At the same time, continuously retreat the delivery sheath 8 backwards until the distal end of the covered stent is completely released;

[0076] At the same time, the delivery system further includes a post-release member. After the distal end of the covered stent is released, the core tube 4 is retreated to disengage the head end fixing member 3, so as to achieve the purpose that the proximal end of the covered stent is also completely released;

[0077] After the release is completed, retreat the delivery system and the delivery guide wire 7 to completely release the covered stent.

[0078] After the release is completed, the covered stent is in a curved state. Because the central curvature of the curved section is close to the bending radius of the aortic arch, it has better wall attachment after release, and can effectively reduce the probability of adverse events such as beak and endoleak.

[0079] The covered stent has good bending flexibility. Combining the above-mentioned release device and release method, through endovascular intervention and the operation mode of withdrawing the sheath, it is implanted into the lesion site of thoracic aortic aneurysm or thoracic aortic dissection. The postoperative recovery time is short, complications can be reduced, and the treatment of the lesion can be achieved.

[0080] The above is only the specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, which should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims

1. A covered stent, characterized in that, It includes a metal stent ring (11) and a film (12). A plurality of the metal stent rings (11) are arranged at intervals in sequence and are all connected to the film (12). In the initial state, the film (12) is in a bent state and has a large bend side and a small bend side. The distance between two adjacent metal stent rings (11) on the large bend side is greater than the distance on the small bend side. The film (12) can be reversely folded so that the large bend side is transformed into the small bend side and the film (12) on this side is stacked, while the small bend side is transformed into the large bend side and the film (12) on this side becomes straightened.

2. The covered stent according to claim 1, characterized in that, The film (12) can be shaped after being bent and deformed at the lesion site to adapt to the shape of the lesion site.

3. The covered stent according to claim 1, wherein, The metal stent ring (11) is made of nitinol wire material.

4. The covered stent according to claim 3, wherein, The wire diameter of the metal stent ring (11) ranges between 0.3 mm and 0.6 mm.

5. The covered stent according to claim 1, characterized in that, The film (12) forms a continuous horizontal section, a bent section and a vertical section at the lesion site, and the bending radius of the center line of the bent section ranges between 40 mm and 60 mm.

6. The covered stent according to claim 1, wherein The metal stent ring (11) is sewn and connected to the film (12).

7. The covered stent according to claim 1, wherein The metal stent ring (11) is connected to the film (12) by hot pressing and forming.

8. A releasing device for a covered stent, characterized in that, It includes a tip soft head (2), a head end fixing member (3), a core tube (4), a tail end fixing tube (5) and the film-covered stent according to any one of claims 1-7. The head end fixing member (3) is connected to the tip soft head (2). The proximal end of the core tube (4) is connected to the head end fixing member (3) and its distal end passes through the inside of the tail end fixing tube (5). The film-covered stent is sleeved on the outside of the core tube (4). The proximal end of the film-covered stent is connected to the head end fixing member (3) and its distal end passes through the inside of the tail end fixing tube (5).

9. The releasing device of the covered stent according to claim 8, characterized in that, It further includes a central core tube (6) and a delivery guide wire (7). The central core tube (6) passes through the inside of the core tube (4). The proximal end of the central core tube (6) is connected to the tip soft head (2). The delivery guide wire (7) passes through the inside of the central core tube (6).

10. The release device of the covered stent according to claim 9, characterized in that, It further includes a delivery sheath tube (8). The delivery sheath tube (8) is sleeved on the outside of the tip soft head (2), the film-covered stent and the tail end fixing tube (5).

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