Covered stent to reduce rupture pressure

Abstract

The present invention discloses a stent graft for reducing rupture pressure, comprising a main body coating, an annular support frame axially fixed on the main body coating in sequence, the main body coating and the annular support frame sequentially form a first tube body, a second tube body and a third tube body from the proximal end to the distal end, the second tube body is provided with a decompression portion for reducing the pressure at the rupture of the blood vessel, the decompression portion is recessed into the second tube body or the decompression portion is a soft structure. The present invention provides a stent graft for reducing rupture pressure that can greatly reduce the squeezing of the stent on the rupture, avoid further expansion of the rupture of the blood vessel intima, and even cause rupture of the blood vessel.

Description

Technical Field

[0001] The present invention belongs to the field of medical devices, and in particular relates to a covered stent that can be used to reduce the rupture pressure of aortic dissection. Background Art

[0002] Dissecting aortic aneurysm is caused by local damage to the aortic intima, high-pressure blood flow rushing into the blood vessel wall, causing the media to tear (the tear in the media is usually at the interface between the inner 1 / 3 and the outer 2 / 3 of the media), splitting the complete aortic wall structure into two, and forming a dissecting cavity in the tear gap between the inner and outer walls of the dissection. In order to distinguish it from the aortic cavity, the dissecting cavity is called the false cavity, and the aortic cavity is called the true cavity.

[0003] According to the Stanford classification, aortic dissection can be divided into type A and type B. Type A: The intimal rupture is located in the ascending aorta, aortic arch or proximal descending aorta, and the extension involves the ascending aorta or aortic arch, and may also extend to the descending aorta or even the abdominal aorta. Type B: The intimal rupture is often located in the isthmus of the aorta, and the extension only involves the descending aorta or extends to the abdominal aorta, but does not involve the ascending aorta and aortic arch. Type A accounts for about 65%-70% of aortic dissections; Type B is equivalent to type III, accounting for about 30%-35%.

[0004] At present, thoracic endovascular aortic repair (TEVAR) has become the first choice for the treatment of complex Stanford type B aortic dissection due to its low trauma, low operative complications and good short- and mid-term clinical results. With the increase of clinicians' experience and the improvement of endovascular graft performance, postoperative complications such as early and mid-term retrograde type A dissection, type I endoleak, stent migration, and aortic rupture have gradually decreased. However, in terms of long-term prognosis, stent-induced new rupture (SINE) has become an important factor affecting its long-term efficacy.

[0005] There are many brands and types of stents used for TEVAR, but they have a common basic characteristic: self-expansion. Therefore, mechanical effects can be exerted on the aortic wall in two different ways. One is radial support force, the magnitude of which depends largely on the magnification of the stent; the other is "elastic recoil force". The self-expanding stent is similar to a spring. When released in the aortic arch or other curved parts, it bends passively. The "elasticity" makes it tend to "elastically recoil", thereby generating a force, which is especially concentrated on the large bend side of the aortic arch and the two ends of the stent. Passive bending of the stent is very common in the endovascular treatment of Stanford type B dissection, because the primary rupture of the dissection often occurs in the isthmus of the aorta, and the stent needs to be released across the descending part of the aortic arch. According to common sense, the more curved the stent is, the greater the elastic recoil force that may be generated, and at the same time, the force is more likely to be concentrated on the end close to the bend.

[0006] Since the stent has radial support force and elastic recoil force, it will continue to be squeezed by the stent at the rupture of the aortic dissection, causing new damage to the vascular endothelium. Therefore, it is necessary to develop a stent that can reduce the pressure at the rupture of the aortic dissection. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a covered stent that can greatly reduce the squeezing of the rupture by the stent, avoid further expansion of the rupture in the vascular endothelium, and even reduce the rupture pressure in case of vascular rupture, in view of the defects of the prior art.

[0008] The technical solution adopted by the present invention to solve the technical problem is:

[0009] A coated stent for reducing rupture pressure comprises a main body coating and an annular support frame axially fixed on the main body coating in sequence, wherein the main body coating and the annular support frame sequentially form a first tube body, a second tube body and a third tube body from the proximal end to the distal end, and the second tube body is provided with a decompression portion for reducing the pressure at the rupture of the blood vessel, and the decompression portion is recessed into the second tube body or is a soft structure.

[0010] Furthermore, in the stent graft for reducing rupture pressure, preferably, the diameters of the first tube body and the third tube body are larger than 10%-15% of the diameter of the blood vessel to be repaired, and the radial width of the pressure relief portion is smaller than or equal to the diameter of the blood vessel to be repaired.

[0011] Furthermore, in the stent graft for reducing rupture pressure, the pressure relief portion is preferably a groove provided on the second tube body, and the width of the groove is equal to or greater than the size of the blood vessel rupture.

[0012] Furthermore, in the stent graft for reducing rupture pressure, the groove is preferably a through groove with openings on both sides in radial direction.

[0013] Furthermore, in the stent graft for reducing rupture pressure, the axial cross-section of the groove is preferably a symmetrical structure, an irregular structure or a combination thereof.

[0014] Furthermore, in the stent graft for reducing rupture pressure, the cross-section of the groove of the symmetrical structure in the axial direction is preferably semicircular, U-shaped, square or trapezoidal.

[0015] Furthermore, in the stent graft for reducing rupture pressure, the pressure reducing portion is preferably a recessed ring surrounding the circumference of the second tube body and recessed into the second tube body.

[0016] Furthermore, in the stent graft for reducing rupture pressure, the axial cross-section of the recessed ring is preferably a symmetrical structure, an irregular structure or a combination thereof.

[0017] Furthermore, in the stent graft for reducing rupture pressure, the cross-section of the recessed ring of the symmetrical structure in the axial direction is preferably semicircular, U-shaped, square or trapezoidal.

[0018] Furthermore, in the stent graft for reducing rupture pressure, the decompression portion preferably includes a decompression coating, and an annular support frame is partially or completely fixed on the decompression coating.

[0019] Furthermore, in the stent graft for reducing rupture pressure, the decompression portion preferably includes a decompression graft with a soft structure, and the decompression graft is wholly or partially not provided with an annular support frame.

[0020] Furthermore, in the stent graft for reducing rupture pressure, it is preferred that a support ring for maintaining the shape of the decompression portion is provided around the decompression graft.

[0021] Furthermore, in the stent graft for reducing rupture pressure, the decompression graft is preferably an integral structure with the main graft or is fixedly connected together.

[0022] Furthermore, in the stent graft for reducing rupture pressure, preferably, the diameter of the second tube body at the decompression coating is the same as the diameter of other parts of the second tube body;

[0023] Alternatively, the decompression coating is concave so that the diameter of the second tube body at the decompression coating is smaller than the diameter of other parts of the second tube body.

[0024] Furthermore, in the stent graft for reducing rupture pressure, the axial length of the first tube body is preferably less than the axial length of the third tube body, and the pressure relief portion on the second tube body is close to the proximal end of the stent. Because the proximal rupture is located close to the proximal end of the stent, the pressure relief portion on the second tube body is close to the proximal end of the stent.

[0025] The present invention provides a decompression portion on the second tube body, and the decompression portion is concave or has a soft structure. After the coated stent is released, the first tube body and the third tube body are firmly attached to the blood vessel wall to expand the true cavity, and blood flows through the cavity of the coated stent. The intimal rupture and the false cavity of the thoracic aortic dissection are isolated. The decompression portion of the second tube body located at the rupture position greatly reduces the squeezing of the rupture due to the radial supporting force of the stent at this position due to its concave or soft structure, thereby avoiding the problem of further expansion of the aortic dissection rupture due to the radial supporting force of the stent acting on the vascular intimal rupture, and even rupture of the blood vessel. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0027] Figure 1 This is a schematic diagram of the front structure of the pressure relief portion of the first implementation mode of Example 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of the front structure of the pressure relief portion of the second implementation mode of Example 1 of the present invention;

[0029] Figure 3 It is a front structural schematic diagram of the third implementation mode of Example 1 of the present invention;

[0030] Figure 4 This is a schematic diagram of the side structure of the pressure reducing portion of the first implementation mode of Example 2 of the present invention;

[0031] Figure 5 This is a schematic diagram of the front structure of the pressure relief portion of the second implementation mode of Example 2 of the present invention;

[0032] Figure 6 This is a schematic diagram of the front structure of the pressure relief portion of the first implementation method of Example 3 of the present invention;

[0033] Figure 7 This is a schematic diagram of the front structure of the pressure relief portion of the second implementation mode of Example 3 of the present invention;

[0034] Figure 8 It is a schematic diagram of the release at the interlayer rupture position of Example 3 of the present invention. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0036] The "proximal end" mentioned in the present invention refers to the part of the stent or stent component close to the patient's heart along the blood flow direction, and the "distal end" refers to the part of the stent or stent component far away from the patient's heart.

[0037] Embodiment 1, as Figure 1-3 As shown, a coated stent for reducing rupture pressure includes a main body coating 151, annular support frames 141, 142, 143, 144 axially fixed on the main body coating 151 in sequence, the main body coating 151 and the annular support frames 141, 142, 143, 144 sequentially form a first tube body 110, a second tube body 120 and a third tube body 130 from the proximal end to the distal end, the second tube body 120 is provided with a decompression portion 160 for reducing the pressure at the rupture of the blood vessel, the decompression portion 160 is recessed into the second tube body 120 or the decompression portion 160 is a soft structure. The axial length of the first tube body 110 is less than the axial length of the third tube body 130, and the decompression portion 160 on the second tube body 120 is close to the proximal end of the stent. Because the proximal rupture is located close to the proximal end of the stent, the decompression portion on the second tube body is close to the proximal end of the stent.

[0038] In the present invention, the stent graft is tubular, and the pressure relief portion 160 includes two different structures: one is that the pressure relief portion 160 of the second tube body 120 is concave toward the center of the second tube body 120, and the second is that the pressure relief portion 160 is a soft structure. The stent graft is an equal-diameter tube body, and can also be a non-equal-diameter tube body. An equal-diameter tube body refers to a first tube body 110, a second tube body 120, and a third tube body 130 having the same or substantially the same diameter. A non-equal-diameter tube body includes the following embodiments: the first is that the first tube body 110 and the third tube body 130 have the same or substantially the same diameter, and the diameter of the second tube body 120 is smaller than that of the first tube body 110 and the third tube body 130. The second is that the diameters of the first tube body 110, the second tube body 120, and the third tube body 130 are all different.

[0039] In this embodiment, the tube body is non-equal diameter, and the diameter of the first tube body 110 and the third tube body 130 is preferably greater than 10%-15% of the diameter of the blood vessel to be repaired, and the radial width of the decompression part 160 is less than or equal to the diameter of the blood vessel to be repaired. After the main body coating 151 stent is released, the first tube body 110 and the third tube body 130 are firmly attached to the blood vessel wall, and the true cavity is expanded to compress the false cavity, so that the blood flows through the cavity of the main body coating 151 stent, and the inner membrane rupture and false cavity of the thoracic aortic dissection are isolated. The decompression part 160 on the second tube body 120 located at the rupture position, because its diameter is smaller than the blood vessel diameter, greatly reduces the extrusion of the rupture caused by the radial support force of the stent at this position, and avoids the expansion or even damage of the aorta caused by the radial support force of the stent acting on the blood vessel intima, forming a new pseudoaneurysm or even rupture of the blood vessel.

[0040] like Figure 1-2 As shown, the division of the first tube body 110, the second tube body 120 and the third tube body 130 is relative and is only for the convenience of explanation. There is no strict structural division among the three. Figure 1 In the embodiment, the first tube body 110 is provided with two annular support frames 141, and the third tube body 130 is provided with four annular support frames 144. The second tube body 120 includes annular support frames 142 and 143, and Figure 2 As shown, the first tube body 110 is provided with a circle of annular support frames 141 , the third tube body 130 is provided with three annular support frames 144 , and the second tube body 120 includes annular support frames 146 , 142 , and 143 . Figure 1 The middle pressure reducing portion 160 may be the entire second tube body 120. Figure 2 The middle pressure reducing portion 160 may be a portion of the second tube body 120. Figure 1 The second tube body 120 is the pressure reducing portion 160 .

[0041] The structure of this embodiment is described in detail below:

[0042] The stent graft includes three tube bodies arranged in sequence from the proximal end to the distal end: a first tube body 110 , a second tube body 120 and a third tube body 130 .

[0043] The first tube body 110 and the third tube body 130 are both composed of a main body coating 151 and annular support frames 141 and 144 fixed on the main body coating 151 .

[0044] The annular support frames 141, 144 are fixed to the inner surface or outer surface of the main body coating 151 by suturing, heat sealing or other methods. The diameters of the first tube body 110 and the third tube body 130 are determined according to the diameter of the blood vessel. The diameters of the two tube bodies can be the same or different. When the diameter of the implanted blood vessel does not change much, it is preferred to use the first tube body 110 and the third tube body 130 with the same or substantially the same diameter. The stent specification of this embodiment is 30 specifications, that is, the diameters of the annular support frames 141, 144 and the main body coating 151 are both 30mm.

[0045] The annular support frames 141 and 144 on the first tube body 110 and the third tube body 130 are both annular support frames with uniform structures. The annular support frames 141 and 144 are equal-wavelength annular supports or high-low wave annular supports of equal diameter. The annular support frames 141 and 144 of the first tube body 110 and the third tube body 130 are fixed to the inner surface or outer surface of the main body coating 151 by suturing, heat sealing or other means. In this embodiment, the single-loop annular support frames 141 and 144 are woven with a superelastic nickel-titanium wire. The wire diameter of the nickel-titanium wire is relatively thin, which can be between 0.2 and 0.5 mm. In this embodiment, a nickel-titanium wire with a diameter of 0.45 mm is used for weaving. The number of Z-shaped or sine waves is 6, and the vertical height of the annular support body bracket is 12 mm.

[0046] like Figure 3 As shown, in this embodiment, the first annular support frame 141 at the proximal end of the first tube body 110 may also be preferably configured as a bare stent to facilitate release after stent assembly.

[0047] like Figure 1-3As shown, in the present invention, a decompression portion 160 is used to decompress the rupture of the blood vessel. The decompression portion 160 is a concave ring that surrounds the second tube body 120 and is concave into the second tube body 120. The concave ring can be a closed structure, that is, a generatrix is ​​formed by rotating around the central axis of the stent, or a non-closed structure, that is, the concave ring is a spiral structure in the circumference of the second tube body 120. The axial cross-section of the concave ring is a symmetrical structure, an irregular structure, or a combination thereof. The cross-section of the concave ring of the symmetrical structure in the axial direction is semicircular, U-shaped, square or trapezoidal. The asymmetric structure can be formed by rotating any curve as a generatrix. The axial cross-section of the decompression portion 160 of this embodiment is a trapezoidal structure, and the decompression portion 160 occupies all or part of the second tube body 120. The decompression portion 160 includes a first tapered portion 161 connected to the first tube body 110, a second tapered portion 163 connected to the third tube body 130, and a straight tube portion 162 between the first tapered portion 161 and the second tapered portion 163.

[0048] The decompression portion 160 includes a decompression coating 152, and annular support frames 142 and 143 are partially or completely fixed on the decompression coating 152. The fully fixed annular support frames 142 and 143 means that according to the performance requirements of the stent itself, the decompression portion 160 and the other parts of the stent use the same or substantially the same annular support frame structure and arrangement method. The decompression portion 160 is partially fixed with annular support frames 142 and 143, which means that the number of annular support frames 142 and 143 provided in the decompression portion 160 is reduced, or the annular support frames 142 and 143 are partially not provided, and only the decompression coating 152 is used to reduce the radial support force of the decompression portion 160 at the rupture. The radial diameter of the decompression portion described in this embodiment is 80%-90% of the first tubular body / third tubular body, and the diameters of the annular support frames 142, 143 and the decompression coating 152 are also adapted to the diameter setting of the decompression portion.

[0049] The decompression film 152 and the main body film 151 are integrally structured or fixedly connected together to form a whole. Both the main body film 151 and the decompression film 152 are made of polymer materials with good biocompatibility. In this embodiment, PET film is preferred, with a film thickness of 0.07mm to 0.1mm, and good mechanical strength and anti-internal leakage performance.

[0050] Embodiment 2: This embodiment is an improvement on embodiment 1.

[0051] like Figure 4-5As shown, the stent graft described in the embodiment of the present invention is also a non-uniform diameter tube body, including three tube bodies arranged in sequence from the proximal end to the distal end: a first tube body 110, a second tube body 120 and a third tube body 130, and the structures of the first tube body 110 and the third tube body 130 are the same as those in Example 1. The diameters of the first tube body 110 and the third tube body 130 of the main body graft 151 stent are equivalent. The second tube body 120 is recessed inwardly on the side close to the rupture to form a groove as a pressure relief portion 160, while the first tube body 110, the second tube body 120 and the third tube body 130 are flush tubular structures on the side away from the rupture.

[0052] The diameters of the first tube body 110 and the third tube body 130 of the main body coating 151 bracket are comparable, and the difference from Example 1 is that the second tube body 120 is recessed inward on the side close to the rupture to form a groove, while the first tube body 110, the second tube body 120 and the third tube body 130 are flush tubular structures on the side away from the rupture. That is, the decompression portion 160 is a groove provided on the second tube body 120, and the width and depth of the groove are equal to or greater than the size of the rupture of the blood vessel, that is, the decompression portion 160 is only provided corresponding to the rupture. The cross-section of the groove is a symmetrical structure, an irregular structure or a combination thereof, and the cross-section here refers to the axial cross-section, and the groove can be a through groove in the radial direction or a non-through groove. A through groove refers to a groove that is open on both sides in the radial direction, and a non-through groove refers to a groove whose edges on all sides are higher than the bottom of the groove. Preferably, the cross-section of the groove of the symmetrical structure in the axial direction is semicircular, U-shaped, square or trapezoidal. Figure 4 As shown, in this embodiment, a through groove with an axial cross-section of a trapezoidal structure is adopted, wherein the groove includes an inclined surface 165 and a groove bottom 166 .

[0053] The decompression part 160 includes a decompression coating 152, and an annular support frame 142, 143 shared with the second tube body 120. The shape of the decompression coating 152 is consistent with the shape of the groove. The decompression coating 152 of this embodiment is a through groove with a trapezoidal axial section, which is an integral structure or a whole fixedly connected with the main coating 151. As in Example 1, an annular support frame is partially or completely fixed on the decompression coating 152 of the decompression part 160. The structure of the annular support frames 142, 143 in the decompression part 160 changes: the annular support frame 142 at the connection part with the first tube body 110 and the third tube body 130 is a special-shaped support frame, and the decompression part 160 is a conical surface, forming a support frame of the groove slope 165, and the rest is a straight cylindrical surface, forming the wall surface of the second tube body 120. The diameter of the annular support frame 143 is reduced, and the part corresponding to the bottom of the groove forms the support frame of the groove bottom 166, and the rest is the support frame of the second tube body 120.

[0054] The remaining structures are the same as those in Example 1 and will not be described in detail here.

[0055] Embodiment 3: This embodiment is another structural form: the pressure relief portion 160 is a soft structure.

[0056] like Figure 6-7 As shown, the coated stent in this embodiment is a tube body of equal diameter, including three tube bodies arranged in sequence from the proximal end to the distal end: a first tube body 110, a second tube body 120 and a third tube body 130.

[0057] The first tube body 110 and the third tube body 130 are the same as those in Embodiment 1-2 and will not be described in detail herein.

[0058] The decompression portion 160 of the second tube body 120 is only provided with a decompression coating 152 of a soft structure, and the decompression coating 152 is not provided with an annular support frame in whole or in part. The decompression portion 160 of the second tube body 120 located at the rupture position is not provided with an annular support frame, so the radial support force of the stent at the rupture position is greatly reduced, thereby greatly reducing the squeezing of the rupture due to the radial support force of the stent at this position, avoiding the expansion or even damage of the aorta due to the radial support force of the stent acting on the vascular endothelium, forming a new pseudoaneurysm or even rupture of the blood vessel. After the coated stent is released, the first tube body 110 and the third tube body 130 are firmly attached to the blood vessel wall, and the blood vessel is restored to its original caliber, so that the blood flow flows through the stent cavity of the main coating 151, and the intimal rupture and tumor-like expansion of the thoracic aortic dissection are isolated.

[0059] The pressure relief portion 160 of the soft structure can be arranged in a circle around the second tube body 120, or can be arranged only in a portion corresponding to the breach. If the pressure relief portion 160 is arranged in a circle, no annular support frame is arranged in the corresponding circle around the pressure relief portion 160. The pressure relief portion 160 corresponding only to the breach is unsupported in this portion, and the second tube body 120 adopts a support frame of a special structure in the radial direction to avoid the pressure relief portion 160. Figure 5-6 As shown, in this embodiment, the pressure reducing portion 160 is arranged in a circle around the second tube body 120 .

[0060] like Figure 6-7 As shown, the division of the first tube body 110, the second tube body 120 and the third tube body 130 is relative and is only for the convenience of explanation. There is no strict structural division among the three. Figure 5 In the embodiment, the first tube body 110 is provided with two annular support frames 141, and the third tube body 130 is provided with six annular support frames 144. The second tube body 120 and the pressure relief part 160 are not provided with annular support frames, but Figure 6 As shown, the first tube body 110 is provided with a circle of annular support frames 141 , the third tube body 130 is provided with five annular support frames 144 , the second tube body 120 includes an annular support frame 146 , and no annular support frame is provided at the position corresponding to the decompression portion 160 . Figure 5The middle pressure reducing portion 160 is the entire second tube body 120. Figure 6 The middle pressure reducing portion 160 may be a portion of the second tube body 120. Figure 5 The second tube body 120 is the pressure reducing portion 160 .

[0061] like Figure 8 As shown, after the stent graft is released, the decompression portion 160 is just in a bent position, where there is no annular support frame and cannot rebound, so there is no elastic rebound force to squeeze the rupture of the inner membrane.

Claims

1. A stent graft for reducing the rupture pressure of aortic dissection, comprising a main body graft, and an annular support frame axially fixed to the main body graft in sequence, wherein the main body graft and the annular support frame sequentially form a first tube body, a second tube body and a third tube body from the proximal end to the distal end, characterized in that: The second tube body is provided with a decompression portion for reducing the pressure at the rupture of the blood vessel, and the decompression portion is recessed into the second tube body or is a soft structure; the decompression portion is a groove provided on the second tube body; the second tube body is recessed inwardly on the side close to the rupture to form the groove of the decompression portion, and the first tube body, the second tube body and the third tube body are flush tubular structures on the side away from the rupture; the diameters of the first tube body and the third tube body are greater than 10%-15% of the diameter of the blood vessel to be repaired, and the radial width of the decompression portion is less than or equal to the diameter of the blood vessel to be repaired; the width of the groove is equal to or greater than the size of the rupture of the blood vessel.

2. The stent graft for reducing aortic dissection rupture pressure according to claim 1, characterized in that: The groove is a through groove with openings on both sides in radial direction.

3. The stent graft for reducing aortic dissection rupture pressure according to claim 1, characterized in that: The axial cross section of the groove is a symmetrical structure, an irregular structure or a combination thereof.

4. The stent graft for reducing aortic dissection rupture pressure according to claim 3, characterized in that: The cross section of the groove of the symmetrical structure in the axial direction is semicircular, U-shaped, square or trapezoidal.

5. The stent graft for reducing the rupture pressure of aortic dissection according to any one of claims 1 to 4, characterized in that: The decompression part comprises a decompression coating, and an annular support frame is partially or completely fixed on the decompression coating.

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