CN116019603A

CN116019603A - Tectorial membrane support and combined support

Info

Publication number: CN116019603A
Application number: CN202111250861.1A
Authority: CN
Inventors: 肖本好; 刘宗麟
Original assignee: Lifetech Scientific Shenzhen Co Ltd
Current assignee: Lifetech Scientific Shenzhen Co Ltd
Priority date: 2021-10-26
Filing date: 2021-10-26
Publication date: 2023-04-28
Also published as: WO2023071792A1

Abstract

The invention relates to a covered stent and a combined stent, the covered stent comprises a stent main body, the stent main body comprises a first stent section and a second stent section connected with the proximal end of the first stent section, the first stent section comprises a covered film, and the covered stent is characterized in that the second stent section comprises at least one first wave rod, the distance from at least one section of the distal end of the first wave rod to the axis of the covered stent is larger than the distance from the proximal end of the first wave rod to the axis of the covered stent, the combined stent comprises a covered stent, and the structure of the bare stent is adjusted, so that the covered stent can avoid excessive stress concentration and impact with the inner wall of a blood vessel after being released and implanted, thereby improving the adaptability of the covered stent to the blood vessel and weakening the original stimulation of the blood vessel.

Description

Tectorial membrane support and combined support

Technical Field

The invention relates to the technical field of interventional medical devices, in particular to a covered stent and a combined stent.

Background

With the rapid rise in the incidence of hypertension, the incidence of arterial-related diseases has increased significantly, and it is expected that the incidence will increase at a rate of more than 40% in the coming 5 to 7 years. Among them, acute StanfordA aortic dissection (acute aorticdissect ntypeA, AADA for short) is the most common and most critical aortic emergency in the field of cardiovascular surgery. If untreated, the mortality rate of one week after AADA onset is up to 50-91%, if only internal medicine conservation treatment is received, the 24-hour mortality rate is up to 20%, and the 48-hour mortality rate is up to 30%. Thus, AADA-diagnosed, if there is no surgical contraindication, an emergency surgical intervention is necessary. However, even under modern medical conditions, perioperative mortality rates are as high as 15-35%.

At present, a minimally invasive endovascular intervention isolation operation can be adopted for treating the diseases, specifically, a covered stent is implanted in a blood vessel to isolate blood flow from aortic dissection, and when the covered stent is used, the unstressed stent in a natural state is usually required to be compressed and loaded into a sheath so as to be transported to a designated position through the sheath and released. After implantation, in order to ensure that the implanted stent graft can be tightly attached to the vessel wall, the diameter of the stent graft is generally smaller than the diameter of the vessel, that is, the stent graft is continuously stressed by the vessel wall, and the vessel wall can continuously and variably extrude the stent graft because the vessel is provided with a certain movement (especially an arterial vessel), and the bare stent part of the stent graft is not provided with a coating structure, so that the vessel wall is easily stimulated along with the movement of the vessel, and even the pressure of the end part to the vessel wall is too concentrated to penetrate into the vessel wall. The bare stent portion plays an important role in anchoring and radial support of the stent, and on the basis of the above, there is a need for a covered stent that can retain the bare stent structure and avoid or reduce irritation of the bare stent to the vessel wall.

Disclosure of Invention

Based on the above, the invention provides a covered stent and a combined stent, which are used for solving the problem that the covered stent is easy to stimulate the vessel wall along with the movement of the vessel and even the pressure of the end part to the vessel wall is too concentrated to penetrate into the vessel wall.

The utility model provides a tectorial membrane support, includes the support main part, the support main part includes first support section and the second support section that links to each other with first support section proximal end, first support section includes the tectorial membrane, the second support section includes at least one first ripples pole, at least one section of first ripples pole distal end to the distance of tectorial membrane support's axis is greater than first ripples pole proximal end to the distance of tectorial membrane support's axis.

In one embodiment, the first wave beam includes at least a first segment near the proximal end and a second segment near the distal end, and the first segment and the second segment extend in opposite directions along the axis.

In one embodiment, the first section is located on the inside of the first carrier section and the second section is located on the outside of the first carrier section.

In one embodiment, the rate of change of the distance of the first waverod from the axis is from positive to negative in the distal to proximal direction, the absolute value of the rate of change increasing and then decreasing.

In one embodiment, the second support section has a plurality of curved surfaces, and the projections of the waverods of the single waveform on the second support section on the curved surfaces coincide.

In one embodiment, the relative distance between the projection of the single wave beam on the curved surface and the projection of the axis on the curved surface increases and decreases from the peak to the trough, or increases and then does not change.

In one embodiment, the second bracket section includes a first band and a second band, the first band and the second band are disposed opposite to each other, and an axial length of the first band is greater than an axial length of the second band.

In one embodiment, the second bracket section comprises a second wave rod, and the second wave rod is opposite to the first wave rod, and the extending direction of the second wave rod is consistent with the first wave rod, but the deflection degree is inconsistent; or the extending direction of the second wave rod is inconsistent with that of the first wave rod, but the deflection degree is consistent; or the extending direction of the second wave rod is inconsistent with that of the first wave rod, and the deflection degree is inconsistent.

In one embodiment, the second support section includes a third wave rod and a fourth wave rod, the third wave rod and the fourth wave rod are staggered to form a net structure, the third wave rod and the fourth wave rod include a first protruding portion and a second protruding portion respectively, and an intersection point of the third wave rod and the fourth wave rod is located at a maximum protruding position of the first protruding portion and a maximum protruding position of the second protruding portion simultaneously.

A combined bracket comprises the covered bracket and further comprises a small bracket, wherein the small bracket is pressed from outside to inside and abuts against the proximal end of the first bracket section, the proximal end of the covered film of the small bracket is flush with the proximal end of the covered film of the first bracket section, and at least one section of tangential direction is parallel to the axis from the proximal end of the second bracket section to the distal end of the second bracket section, which is close to the small bracket.

According to the covered stent and the combined stent provided by the invention, through adjusting the structure of the bare stent (namely the second stent section), the covered stent is prevented from generating overlarge stress concentration and impact with the inner wall of a blood vessel after being released and implanted, so that the adaptability of the covered stent to the blood vessel is improved, the original stimulation of the bare stent position to the blood vessel is weakened, the combined stent also ensures that the extrusion deformation of the bare stent part of the original covered stent can not stimulate the blood vessel wall when being matched with other stents, and the risk that the bare stent is in point contact with the blood vessel wall, so that the stress concentration causes damage to the blood vessel wall and even the blood vessel wall is punctured is reduced and avoided.

Drawings

FIG. 1 is a schematic view showing the structure of a stent graft according to a first embodiment of the present invention;

FIG. 2 is a schematic structural view of a bare stent segment of a stent graft according to a first embodiment of the present invention;

FIG. 3 is a schematic view showing a state of the stent graft in the release phase in the first embodiment of the present invention;

FIG. 4 is a schematic diagram showing the state of the art in the release phase of a stent graft of a bare stent;

FIG. 5 is a schematic view of a prior art stent graft in a state after implantation of a straight bare stent graft;

FIG. 6 is a schematic view showing a state after the stent graft is implanted in the first embodiment of the present invention;

FIG. 7 is a schematic structural view of a bare stent segment of a stent graft in one embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of the projection surface D of FIG. 7;

FIG. 9 is a schematic view showing the structure of a stent graft according to a second embodiment of the present invention;

FIG. 10 is a schematic view showing an operation state of a stent graft according to a third embodiment of the present invention;

FIG. 11 is a schematic diagram of the operation of a prior art bare stent graft in combination with a small stent;

FIG. 12 is a schematic view showing the operation of the stent graft with a small stent in a fourth embodiment of the present invention;

FIG. 13 is a schematic view showing the construction of a stent graft according to a fifth embodiment of the present invention;

FIG. 14 is a schematic structural view of a bare stent segment of a stent graft according to a fifth embodiment of the present invention;

FIG. 15 is a schematic view showing an initial state of a release stage of the stent graft according to the fifth embodiment of the present invention;

FIG. 16 is a schematic view showing an end state of a release phase of the stent graft in the fifth embodiment of the present invention;

FIG. 17 is a schematic view showing the construction of a stent graft according to a sixth embodiment of the present invention;

FIG. 18 is a first view structural schematic diagram of a bare stent segment of a stent graft according to a third embodiment of the present invention;

fig. 19 is a second view structural schematic diagram of a bare stent segment of a stent graft in a third embodiment of the invention.

Detailed Description

In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. The drawings illustrate preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

In the field of interventional medical devices, it is generally defined that the implant (e.g., a luminal stent) is proximal at the end proximal to the heart and distal at the end distal to the heart after release. "axial" generally refers to the longitudinal direction of the implant as it is delivered, and "radial" generally refers to the direction of the implant perpendicular to its "axial" direction, and defines the "axial" and "radial" directions of any of the components of the implant in accordance with this principle.

First embodiment

The covered stent 100 comprises a bare stent 10 and a covered film 20, wherein the bare stent 10 is made of a material with good biocompatibility, such as nickel titanium, stainless steel and the like, and in general, the bare stent 10 comprises a plurality of metal wave rings which are distributed at intervals. The coating 20 is made of polymer material with good biocompatibility, such as PTFE, FEP, PET

Referring to fig. 1-2, fig. 1 is a schematic structural diagram of a stent graft 10 in this embodiment, fig. 2 is a schematic structural diagram of a bare stent segment 112 of the stent graft 10 in this embodiment, the stent graft 10 includes a stent body 11 and a stent 12 covering the surface of the stent body 11, the stent body 11 includes a plurality of wavy rings axially arranged along the centerline of the stent, and is generally made of a material with good biocompatibility, such as nickel titanium, stainless steel, etc., and the stent 12 is made of a polymer material with good biocompatibility, such as PTFE, FEP, PET, etc.

The stent body 11 comprises a covered stent section 111 (first stent section) and a bare stent section 112 (second stent section) connected to the proximal end of the covered stent section 111, the bare stent section 112 comprising a wavy annular ring of bare waves, it being understood that the bare stent section 112 may comprise a plurality of wavy annular rings, and in another embodiment the stent body comprises a helical annular ring. In the present embodiment, the cover films 12 on the inner and outer surfaces of the stent body 11 are fixed by means of hot melt bonding, other connection means such as adhesion or stitching can achieve the same effect in addition to the hot melt bonding, the present embodiment is not limited, and each of the wavy rings may be connected to each other or connected only by the cover film 12, and the present embodiment is not limited.

In the present embodiment, the bare stent section 112 comprises at least one first wave rod 1121, at least a section of the distal end of the first wave rod 1121 being farther from the axis of the stent body 11 than at least a section of the proximal end thereof, that is, at least a section of the distal end of the first wave rod 1121 being outwardly offset with respect to at least a section of the proximal end thereof, such that the proximal peak section of the first wave rod 1121 is closer to the axis of the stent body 11 with respect to the proximal trough section thereof.

Specifically, the first wave rod 1121 includes at least a first segment 11211 near the peak and a second segment 11212 near the trough, the first segment 11211 extending inward as viewed from the distal end toward the proximal end, the second segment 11212 extending outward as viewed from the proximal end toward the distal end, the first segment 11211 extending outward and the second segment 11212 extending inward as viewed from the proximal end toward the distal end. Accordingly, the first and

second segments

11211, 11212 extend in opposite directions along the axis. That is, as viewed in the distal-to-proximal direction (i.e., the direction from the stent body 11 toward the bare stent segment 112), the first wave rod 1121 extends outward and then inward, and the rate of change of the distance of the first wave rod 1121 from the axis changes from a positive value to a negative value (positive value increases, negative value decreases) in the distal-to-proximal direction. Further, the first segment 11211 is located inside the stent graft segment 111 of the stent graft 10 and the second segment 11212 is located outside the stent graft segment 111 of the stent graft 10.

In another embodiment, the absolute value of the rate of change of the distance of the first waverod from the axis increases and decreases from the distal end to the proximal end, thereby making the proximal and distal ends of the first waverod more smooth and more compliant with the direction of extension of the vessel wall.

The covered stent 10 comprises a natural state and a compressed state, when in implantation surgery, the covered stent 10 is compressed to the compressed state and then is loaded into a conveying sheath, a bare stent section 112 of the covered stent 10 is bound on a TIP at the distal end of a sheath core tube, the covered stent 10 is delivered to an implantation position in a body along the sheath tube, then an outer tube of the conveying sheath tube is gradually withdrawn, the bare stent section 112 of the covered stent 10 is bound on the TIP at the distal end of the sheath core tube, the rest is naturally expanded, and after confirming that the position of the covered stent 10 is accurate, the bare stent section 112 of the covered stent 10 at the TIP position is released, so that the release of the covered stent 10 is realized.

According to the above procedure, during the release process of the stent graft 10, there is a stage in which the bare stent segment 112 is bound to the TIP head, and the stent graft segment 111 is naturally expanded, and during this stage, the bare stent segment 112 is in a semi-open state, referring to fig. 3-4, fig. 3 is a schematic view of the release stage of the stent graft 10 in this embodiment, and fig. 4 is a schematic view of the release stage of the straight bare stent graft, it is obvious that, since the first wavy strut 1121 has a concave curved structure, the area of the opening region 1123 formed by the first wavy strut 1121 and the adjacent wavy strut is larger than the opening region of the opening region 1124 of the straight tubular stent graft, i.e., in this embodiment, the bare stent segment 112 can provide a larger open area, avoiding the blood flow from being blocked. In addition, due to the characteristics of the fluid, the blood flow velocity near the center line of the blood vessel is slightly faster than that near the wall of the blood vessel, while the change rate of the distance from the first wave rod 1121 to the axis in the present embodiment from the distal end to the proximal end is from a positive value to a negative value, the distal end of the bare stent segment 112 where the first wave rod 1121 is located is closer to the wall of the blood vessel, thereby leading to a larger opening area 1123 at the position of the wall of the blood vessel, providing a more sufficient space for the blood flow with a slower velocity at the position of the wall of the blood vessel, and ensuring the smoothness of the blood flow.

After the stent graft 10 is implanted, the stent graft 10 stays in the blood vessel, in order to ensure that the stent graft 10 is fully expanded and tightly attached to the inner wall of the blood vessel, the diameter of the stent graft 10 in the natural state is slightly larger than the inner diameter of the blood vessel at the position to be implanted, that is, the inner wall of the blood vessel can generate pressure on the stent graft 10, referring to fig. 5, fig. 5 is a schematic diagram of the state after the implantation of the stent graft 90, the stent graft 90 is pressed when being implanted, the contact area between the stent graft segment 911 and the blood vessel wall is larger, so that the shape of the stent graft 90 is more prone to maintaining the shape of the stent graft segment 911 attached to the inner wall of the blood vessel, and the connecting position of the stent graft segment 911 and the stent segment 912 can deform to adapt to the expanded state after the implantation of the stent graft 90, that is slightly concave inwards, so that the stent graft segment 911 is in the shape of the horn shape and the vessel wall is easily damaged when the stent graft segment 912 is in the shape, and the pressure is too large to the vessel wall is easily damaged when the stent wall is in the contact with the vessel wall. In addition, when the bare stent segment 912 is released, the deformation amount of the proximal end thereof with respect to other positions is maximum, the stroke for restoring the expanded state is longest, and the released force is also maximum, and at this time, when the proximal end of the bare stent segment 912 collides with the vessel wall (point contact), excessive impact is easily caused to the vessel wall.

Referring to fig. 6, fig. 6 is a schematic view of a state of the stent graft 10 after implantation in the present embodiment, since the natural state of the bare stent segment 112 protrudes outward at a position close to the distal end of the stent graft segment 111, that is, the distal end of the bare stent segment 112 protrudes outward relative to the stent graft segment 111, the blood vessel wall always contacts and presses the distal end of the bare stent segment 112, that is, the distal end of the bare stent 112 has undergone deformation compensation, on this basis, the bare stent segment 212 forms a nearly straight cylinder shape, and further since the natural state of the bare stent segment 112 is recessed inward at a position far from the proximal end of the stent graft segment 111, the proximal end of the bare stent segment 212 does not contact the blood vessel wall, further, when the bare stent segment 212 is released, the proximal end of the bare stent segment 112 contacts the blood vessel wall, and then the proximal concave segment of the bare stent segment 112 gradually contacts the blood vessel wall, thereby avoiding impact of the bare stent segment 112 to the blood vessel wall.

In another embodiment, the bare stent section 112 comprises a plurality of first struts 1121, the plurality of first struts 1121 being spaced apart.

In another embodiment, the bare stent section 112 comprises a plurality of first struts 1121, the plurality of first struts 1121 being distributed consecutively.

In another embodiment, the bare stent section 112 is entirely comprised of the first waveguide 1121.

In this embodiment, since the distal end of the bare stent segment 112 has a protruding structure that abuts against the vessel wall after release, the anchoring by the anchor structure can be omitted, thereby reducing damage to the vessel wall.

In another embodiment, the bare stent segment 112 may be partially covered by the covering film 13, but the covered length is 75% or less of the total length L of the bare stent segment 112, in order to ensure that the proximal end position of the covering film 13 has sufficient supporting force to avoid deformation or wrinkling due to blood impact.

In another embodiment, as shown in fig. 7, fig. 7 is a schematic structural diagram of the bare support segment 112, where the bare support segment 112 has a plurality of curved surfaces D, so that the projection of the wave rod 1122 of a single waveform on the curved surfaces D overlaps and forms a projected waveform 1123 on the projection surface. The single waveform means a single peak and a wave rod connected to the peak. The number of curved surfaces D is equal to the number of peaks of the single-waveform wave rod 1122. Further, referring to fig. 8, for the projection of any wave rod 1122 on the curved surface D (i.e., the wave 1123), the distance projected on the same curved surface as the axis (i.e., the axis) increases and decreases with increasing peak-to-valley or does not change, that is, the distance L1 from the position near the peak to the axis is smaller than the distance L2 from the position near the peak to the valley to the axis, and L2 is smaller than or equal to the distance L3 from the position near the valley to the axis.

L1< L2.ltoreq.L3. Such an arrangement ensures uniformity and symmetry of the bare stent segment 112 such that the bare stent segment 112 has uniform radial support force.

Second embodiment

Referring to fig. 9, fig. 9 is a schematic structural diagram of a stent graft 20 according to a second embodiment of the present invention, which is different from the first embodiment in that the stent graft 20 has no strictly bare stent segment, and a stent graft 22 is also disposed between a proximal end band 212 and a main body band 211 of the stent graft 20, and the present embodiment has a better blood-insulating effect than the first embodiment.

Third embodiment

In this embodiment, referring to fig. 10, fig. 10 is a schematic view illustrating an operation state of a stent graft 30 according to a third embodiment of the present invention, wherein the third embodiment is different from the first embodiment in that the stent graft 30 includes a first waveguide 3121 and a second waveguide 3122 opposite to the first waveguide 3121, and when the stent graft is implanted in the aortic arch, the stent graft 30 must not block the branch vessel due to the importance of the upper branch vessel, so that the proximal end of the stent graft 30 needs to be accurately positioned at the edge of the branch vessel, and the distal end of the first waveguide 3121 protrudes and the proximal end is concave, so that the bare stent segment 312 extends into the branch vessel at a position close to the branch vessel, and the ring where the first waveguide 3121 is located is tightly anchored at the opening of the branch vessel, thereby increasing the overall stability of the stent graft 30. Further, since the extending direction of the first wave lever 3121 coincides with the extending direction of the aortic arch, the proximal end of the first wave lever 3121 does not abut the inner wall of the blood vessel at the aortic arch position.

On this basis, the proximal and distal offsets (i.e., the degree of concavity of the proximal end and the degree of convexity of the distal end) of second wave beam 3122 are reduced, and the curved state of the aortic arch can be better adapted.

It should be noted that, although the extending direction of the second wave beam 3122 and the extending direction of the aortic arch are not identical, since the second wave beam 3122 is disposed opposite to the first wave beam 321, the proximal end portion of the second wave beam 3122 does not abut the inner wall of the blood vessel at the aortic arch position as well.

In another embodiment, the second wave beam follows the direction of extension of the aortic arch, i.e. the second wave beam is in a natural state parallel with respect to the axis of the stent graft or extends outwards with respect to the axis of the stent graft.

In another embodiment, the second wave beam follows the direction of extension of the aortic arch, the proximal end of the second wave beam being offset inwardly with respect to the axis of the stent graft in a natural state, and the distal end of the second wave beam being offset outwardly with respect to the axis of the stent graft in a natural state.

Thus, in addition to first waveguide 3121, bare stent segment 312 of stent graft 30 may include a second waveguide 3122 that is consistent with the direction of extension of first waveguide 3121, but is not deflected to the extent (i.e., angle and distance of extension) and/or is not consistent with the direction of extension.

Fourth embodiment

In this embodiment, the covered stent is used in combination with a small stent, and referring to fig. 11-12, fig. 11 is a schematic diagram of the operation of the covered stent 90 of the straight bare stent in combination with a small stent, and fig. 12 is a schematic diagram of the operation of the covered stent 40 of this embodiment in combination with a small stent.

For the straight bare stent graft 90, the small stent 80 presses the proximal end of the stent graft segment 911, causing the proximal end of the stent graft segment 911 to dent inward, driving the distal end of the bare stent segment 912 to move toward the axis of the straight cylindrical stent graft 90, and the bare stent segment 912 deforms due to the nature of the natural outward expansion of the straight cylindrical stent graft 90. The proximal end of the bare stent 912 will abut against the vessel wall, resulting in extrusion of the vessel wall, since the contact between the proximal end of the bare stent segment 912 and the vessel wall is point contact, the proximal end of the bare stent segment 912 will exert a greater pressure on the vessel wall, which is prone to damage to the vessel wall.

For the stent graft 40 in this embodiment, the small stent 80 also presses the proximal end of the stent graft segment 411, which causes the proximal end of the stent graft segment 411 to recess inward, and then drives the distal end of the first waveguide 4121 on the bare stent segment 412 to move toward the axial direction of the stent graft 40, so that the bare stent segment 412 deforms. The deformation of the first wave lever 4121 has the following characteristics:

1. the distal end of the first wave rod 4121 is moved toward the axial direction of the stent graft 40 by the pressure of the small stent 80, and the pressure is transmitted with the rod body of the first wave rod 4121.

2. The proximal end of the first wave rod 4121 moves along with the movement of the distal end thereof toward the axial direction of the stent graft 40, and at this time, the proximal end of the first wave rod 4121 is deflected by the force transmitted from the distal end of the rod body, and when the external force and the elastic force of the self-expansion of the first wave rod 4121 are balanced, the relative position of the proximal end of the first wave rod 4121 with respect to the distal end is more biased to the outside than in the natural state, i.e., the proximal end of the first wave rod 4121 is deflected toward the outside.

In combination with the above characteristics, the proximal end of the first waveguide 4121 deflects outward, but since the rate of change of the distance of the first waveguide 4121 from the distal end to the axis is from positive to negative, i.e., the distal end of the first waveguide 4121 extends outward and the proximal end extends inward, the proximal end of the first waveguide 4121 deflects toward the horizontal direction when deflected outward, and no point contact between the proximal end of the bare stent section 412 and the vessel wall occurs, i.e., there is at least a certain segment of waveguide from the proximal end of the first waveguide 4121 to the distal end of the first waveguide 4121, the tangent of which is parallel to the axis, so that the proximal end of the bare stent section 412 always does not collide and squeeze with the vessel wall, and damage to the vessel wall can be effectively prevented.

Fifth embodiment

13-14, the stent graft 50 includes a stent graft segment 511 and a bare stent segment 512, wherein the bare stent segment 512 includes a first band 5121 and a second band 5122, the first band 5121 and the second band 5122 being disposed opposite one another, the axial length of the first band 5121 being greater than the axial length of the second band 5122, and in particular, the axial length of the first band 5121 being at least 1.5 times greater than the axial length of the second band 5122.

Referring to fig. 15 to 16, fig. 15 is a schematic view showing an initial stage of release of the stent graft 50 at a predetermined position by a sheath in the present embodiment, and fig. 16 is a schematic view showing an end stage of release of the stent graft 50 at a predetermined position by a sheath in the present embodiment. In the release process, the bare stent segment 512 of the covered stent 50 is fixed at the TIP head 520 of the sheath, the first wave band 5121 is close to the large curved side of the aortic arch, the second wave band 5122 is close to the small curved side of the aortic arch, and the axial length of the first wave band 5121 is larger than that of the second wave band 5122, so that the first wave band 5121 and the second wave band 5122 can deviate to one side of the second wave band 5122 at the TIP head 520, and when leaving the TIP head 520, the second wave band 5122 at the small curved side has shorter stroke for restoring the expansion state, has smaller impact on the small curved side and can better protect the inner wall of a blood vessel; in addition, the first band 5121 of the greater curvature is longer, which upon release, the distal end of the first band 5121 contacts the greater curvature first, and the free (i.e., proximal) end of the first band 5121 is prevented from striking the blood vessel due to the curvature of the blood vessel at the greater curvature.

Sixth embodiment

17-19, the stent graft 60 includes a stent graft segment 611 and a bare stent segment 612, the bare stent segment 612 includes a plurality of third and fourth wavebars 6121 and 6122 alternately arranged, and the third and fourth wavebars 6121 and 6122 have the same structural properties as the first wavebars in the first embodiment, except that the plurality of alternately arranged third and fourth wavebars 6121 and 6122 form a lattice structure, and the third and fourth wavebars 6121 and 6122 of the lattice structure satisfy at the same time, and the third and fourth wavebars 6121 and 6122 extend outward first and then extend inward as viewed from the distal end to the proximal end, and then the rate of change of the distance of the third and fourth wavebars 6121 and 6122 from the axis is from a positive value to a negative value (positive value increases, negative value decreases) in the distal end to the proximal end direction. That is, the third wave rod 6121 and the fourth wave rod 6122 have protruding portions respectively to abut against the vessel wall after the release of the stent graft 60, in this embodiment, the crossing points of the third wave rod 6121 and the fourth wave rod 6122 are located at the peak positions of the protruding portions of the third wave rod 6121 and the fourth wave rod 6122, when the stent graft 60 is released, the crossing points serve as the points where the stress of the stent graft 60 on the vessel wall is most concentrated, and the stress of the crossing points is distributed along the two directions of the third wave rod 6121 and the fourth wave rod 6122, so that the problem that the stress is too concentrated and the vessel wall is damaged when the third wave rod 6121 and the fourth wave rod 6122 act alone is avoided.

Further, the third wave rod 6121 and the fourth wave rod 6122 overlap each other, in a natural state, the intersection point of the third wave rod 6121 and the fourth wave rod 6122 is also located at the vertex position of the protruding portion of the third wave rod 6121 and the protruding portion of the fourth wave rod 6122, after the film covered stent 60 is released, the third wave rod 6121 and the fourth wave rod 6122 are deformed under pressure, and the stress concentration point is located at the intersection point, at this time, the third wave rod 6121 and the fourth wave rod 6122 are adaptively deformed due to the overlapping, so that the position of the intersection point is changed, thereby adapting to the complex environment in the blood vessel more, and meanwhile, the third wave rod 6121 and the fourth wave rod 6122 can mutually support as each other, so as to provide necessary supporting force for the film covered stent 60. The usage environment of the stent graft 60 according to the present embodiment includes a blood vessel having a complex curved shape such as an aortic arch, and the structure in which the third wave bar 6121 and the fourth wave bar 6122 are overlapped with each other has a better environment adaptation capability.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. The utility model provides a tectorial membrane support, includes the support main part, the support main part includes first support section and the second support section that links to each other with first support section proximal end, first support section includes the tectorial membrane, its characterized in that, the second support section includes at least one first ripples pole, at least one section of first ripples pole distal end is to the distance of the axis of tectorial membrane support is greater than first ripples pole proximal end to the distance of the axis of tectorial membrane support.

2. The stent graft of claim 1, wherein said first wave beam comprises at least a first segment proximate said proximal end and a second segment proximate said distal end, said first segment and said second segment extending in opposite directions along said axis.

3. The stent graft of claim 2, wherein said first segment is positioned inside said first stent segment and said second segment is positioned outside said first stent segment.

4. The stent graft of claim 2, wherein the rate of change of the distance of said first waverod from said axis varies from a positive value to a negative value in the distal to proximal direction.

5. The stent graft of claim 1, wherein said second stent segment has a plurality of curved surfaces, and wherein the projections of the wavebars of a single waveform on said second stent segment on said curved surfaces coincide.

6. The stent graft of claim 5, wherein the relative distance between the projection of said single waver on said curved surface and the projection of said axis on said curved surface increases and decreases from peak to valley, or increases and decreases from peak to peak.

7. The stent graft of claim 1, wherein said second stent segment comprises a first band and a second band, said first band and second band being disposed opposite one another, and wherein the axial length of said first band is greater than the axial length of said second band.

8. The stent graft of claim 1, wherein said second stent segment comprises a second strut, said second strut being oriented in a direction consistent with said first strut but not in a degree of deflection relative to said first strut; or the extending direction of the second wave rod is inconsistent with that of the first wave rod, but the deflection degree is consistent; or the extending direction of the second wave rod is inconsistent with that of the first wave rod, and the deflection degree is inconsistent.

9. The stent graft of claim 1, wherein said second stent segment comprises a third and a fourth struts, said third and fourth struts being staggered to form a mesh, said third and fourth struts comprising a first and second convex portion, respectively, and wherein the intersection of said third and fourth struts is located at the maximum convex position of said first and second convex portions, respectively.

10. A combination stent comprising the stent graft of claims 1-9, further comprising a small stent, the small stent being compressed from the outside inward against the proximal end of the first stent section, the proximal end of the stent graft of the small stent being flush with the proximal end of the stent graft of the first stent section, the proximal end of the second stent section being in the vicinity of the distal end of the small stent from the second stent section, at least the tangential direction of a segment being parallel to the axis.