Disclosure of Invention
The invention aims to provide a covered stent which does not need customization, has wide application range and is simple in operation.
The invention adopts the following technical scheme that the tectorial membrane bracket comprises a bracket main body, an outer branch and at least one inner branch, wherein the bracket main body is of a tubular structure with a tectorial membrane on the surface, a concave part with a radial recess is formed on the surface, the outer branch is hung outside the bracket main body, one end of the outer branch is connected with the side wall of the concave part, an inner opening is formed on the side wall of the concave part, the inner branch is adhered and fixed on the inner wall of the bracket main body, one end of each inner branch is connected with the side wall of the concave part, an outer opening is formed on the side wall of the concave part, and the outer opening is closer to the far end than the inner opening.
In some embodiments, the number of internal branches is two, a first internal branch and a second internal branch, the first internal branch having a first external opening on a sidewall of the recess and the second internal branch having a second external opening on a sidewall of the recess, the second external opening being closer to a distal end than the first external opening.
In some embodiments, the first inner branch extends proximally from the first outer opening.
In some embodiments, the second inner branch extends distally from the second outer opening.
In some embodiments, the second inner branch also extends circumferentially along the stent body from the second outer opening as it extends in the distal direction.
In some embodiments, the first inner branch also extends circumferentially along the stent body from the first outer opening as it extends in the proximal direction.
In some embodiments, the second inner branch extends from the second outer opening in a proximal direction, and along with the extension in the proximal direction, the second inner branch also extends from the second outer opening in a circumferential direction along the stent body, and the second inner branch extends in a circumferential direction away from the first inner branch in the circumferential direction.
In some embodiments, the length of the outer branch is 5mm to 20mm.
In some embodiments, the outer branch has a flexibly deformable flexible section extending outwardly from the inner opening.
In some embodiments, the flexible segment is constructed of a flexible film material.
In some embodiments, the transition section is 2 mm-10 mm in length and no more than 1/2 of the total length of the outer branch.
In some embodiments, the outer branch and the inner branch are each provided with a developing member made of a radiopaque material.
In some embodiments, the developing member is disposed at the inner opening or the outer opening in a circumferential direction.
In some embodiments, the developing members are disposed on the outer branch or the inner branch along respective extending directions.
In some embodiments, the developing member is fixed by hot pressing or sewing.
In some embodiments, the stent body comprises a proximal tube, a middle tube and a distal tube, which are sequentially arranged from the proximal end to the distal end, wherein the diameter of the middle tube is smaller than that of the proximal tube and the distal tube, and the middle tube forms the concave part.
In some embodiments, two ends of the middle tube body are respectively connected with the proximal tube body and the distal tube body through a transition tube body, the transition tube body is provided with a transition support frame which is used for supporting the coating film and is in a truncated cone shape, and the small end of the transition support frame faces the middle tube body.
In some embodiments, the proximal tube body is provided with a rear release member having a radially contractible annular structure secured to the cover and projecting proximally beyond the proximal edge of the cover.
In some embodiments, the rear release member is provided with barbs protruding in the circumferential direction.
In some embodiments, the end of the cover film is provided with a developed indicia made of a non-transmissive material.
According to the technical scheme, the invention has at least the following advantages and positive effects:
In the covered stent, the outer branch and at least one inner branch are integrally formed on the stent main body, the branches can respectively provide positioning and supporting functions for the externally connected branch stent, and the branches are positioned in the concave part of the stent main body, a certain gap is formed between the branches and the vessel wall based on the radial recess of the concave part, so that enough operation space can be provided for a guide wire and a catheter during intracavity treatment, and the externally connected branch stent can be conveniently and rapidly sent into a branch vessel in the operation process. Meanwhile, as the concave parts are recessed along the radial direction, after each branch stent is implanted into a blood vessel, the covered stent can not be extruded to the branch blood vessel to cause the blockage of the branch blood vessel. The outer branch and the inner branch are correspondingly utilized to anchor the covered stent, so that the operation is simpler, and the operation process is shortened.
Particularly, among the branches of the covered stent, the most proximal branch is an outer branch which is suspended outside the stent main body, and when the covered stent is sent to a preset position of an aortic vessel, the outer branch can be stretched into a branch arterial vessel such as a innominate artery, so that whether the covered stent is delivered in place or not can be conveniently determined, and meanwhile, after the outer branch is released, the outer branch is matched with the branch arterial vessel based on the matching of the outer branch and the branch arterial vessel, the stent main body is matched with the aortic vessel, so that the covered stent is not easy to shift as a whole, and the implantation of the subsequent branch stent is convenient. The inner branch which is positioned at the far end of the outer branch is positioned in the bracket main body, the inner branch does not exceed the bracket main body, but only exposes the outer opening at the side wall of the bracket main body, and the operation space provided by the concave part is matched, so that the branch bracket can be implanted into the branch arterial vessel through the inner branch, and can be more conveniently implanted into the branch arterial vessel, and the inner branch does not need to be accurately opposite to the inlet of the branch arterial vessel, so that the tectorial membrane bracket has wider applicability and higher universality.
The covered stent of the invention ensures that the main artery stent and the external branch artery stent are respectively independent structures, are suitable for various normal and shape-variation blood vessels, can respectively select the main artery stent blood vessel and the branch artery stent blood vessel with proper sizes according to the specific condition of pathological changes, are combined into a set of stent blood vessel system which is most suitable for patients, avoid customizing the stent, can be produced in batches, and effectively save the time and have the efficacy of easy operation.
Detailed Description
Exemplary embodiments that embody features and advantages of the present invention will be described in detail in the following description. It will be understood that the invention is capable of various modifications in various embodiments, all without departing from the scope of the invention, and that the description and illustrations herein are intended to be by way of illustration only and not to be construed as limiting the invention.
The invention provides a covered stent which can be used for interventional therapy of aortic vascular lesions. Based on the stent graft, the aortic arch three main branch arterial blood flow channels can be reconstructed.
For ease of description, the definition "proximal" herein refers to the end that is closer to the heart in the direction of blood flow, and "distal" refers to the end that is farther from the heart. Wherein the intra-arterial blood flow direction is from the proximal end to the distal end.
In the first embodiment, please refer to the structure and the usage state shown in fig. 1 to 4.
Referring first to fig. 1 and 2, the stent graft 100 of the present embodiment mainly includes a stent main body 1, and one outer branch 2 and two inner branches 3, 4 integrally connected with the stent main body 1. The outer branches 2 are located outside the bracket main body 1, the two inner branches 3 and 4 are located inside the bracket main body 1, and the outer branches 2 and the two inner branches 3 and 4 are sequentially distributed from the proximal end to the distal end and are respectively connected and fixed with the bracket main body 1. For ease of description, the two inner branches 3, 4 are divided into a first inner branch 3 closer to the proximal end and a second inner branch 4 closer to the distal end.
Referring mainly to fig. 1, a stent body 1 is a tubular structure with a coating 102 on the surface, and its skeleton mainly comprises a plurality of annular supporting frames 101 arranged along the axial direction. The support frame 101 is formed in a ring shape by a rigid wire having elasticity, and can be contracted or expanded in the radial direction.
The support frame 101 may be made of a shape memory alloy material, preferably a nickel titanium alloy material. The cover film 102 may be formed from any suitable cover film material including, but not limited to, low porosity woven or knitted polyester, dacron material, expanded polytetrafluoroethylene, polyurethane, silicone, ultra-high molecular weight polyethylene, or other suitable material.
Each of the support frames 101 is fixed to the inner surface or the outer surface of the cover film 102 by sewing or hot pressing, and the cover film 102 is supported by the plurality of support frames 101 so that the stent body 1 can be unfolded and held in a tubular structure when in use, thereby constructing a channel through which blood passes.
In the direction from the proximal end to the distal end in the axial direction of the stent body 1, the stent body 1 has a proximal tube 11, a first transition tube 14, an intermediate tube 12, a second transition tube 15, and a distal tube 13 in this order.
Wherein, the proximal tube 11, the middle tube 12 and the distal tube 13 are respectively in a tubular structure with basically equal diameters. The diameter D12 of the intermediate tube body 12 is smaller than the diameter D11 of the proximal tube body 11 and the diameter D13 of the distal tube body 13, whereby a radially recessed recess 103 is formed at the intermediate tube body 12 as a whole of the stent body 1.
As an example, the diameter D12 of the intermediate tube 12 may be approximately 70% -80% of the diameter D11 of the proximal tube 11 and approximately 75% -95% of the diameter D13 of the distal tube 13. It will be appreciated that the diameter D11 of the proximal tube 11 may be the same as or different from the diameter D13 of the distal tube 13.
The first transition pipe body 14 and the second transition pipe body 15 are both in a truncated cone shape, i.e. are both in a tubular structure with gradually changed diameters. The proximal end of the first transition tube 14 is connected to the proximal tube 11 and the distal end of the first transition tube 14 is connected to the intermediate tube 12. Accordingly, the proximal diameter of the first transition tube 14 is greater than the distal diameter thereof. The proximal end of the second transition tube 15 is connected to the intermediate tube 12 and the distal end of the second transition tube 15 is connected to the distal tube 13, and accordingly the proximal diameter of the second transition tube 15 is smaller than the distal diameter thereof.
The first transition pipe body 14 and the second transition pipe body 15 enable the middle pipe body 12 to form gentle transition connection with the proximal pipe body 11 and the distal pipe body 13 respectively, and the risk of internal leakage or local thrombus caused by local formation of structural dead angles similar to grooves due to abrupt shape changes is avoided.
Each segment of the tube body 11, 12, 13, 14, 15 of the stent body 1 is composed of one or more supporting frames 101 and a covering film 102 supported by these supporting frames 101.
In particular, the support frame 101 at the first transition duct body 14 and the second transition duct body 15 is defined as a transition support frame 104. The transition support 104 has a truncated cone shape to respectively hold the truncated cone-shaped structures of the first transition pipe body 14 and the second transition pipe body 15. The small end of the transition support 104 faces the intermediate pipe body 12.
In this embodiment, only one transition support frame 104 is provided on each of the first transition pipe body 14 and the second transition pipe body 15. It is to be understood that the number of the transition support frames 104 is not limited, and when a plurality of transition support frames 104 are required to be provided, the plurality of transition support frames 104 are all in a shape of a truncated cone and are located on the same table surface.
Whereas for the proximal 11, intermediate 12 and distal 13 tubular bodies, their respective support brackets 101 are correspondingly cylindrical, so as to maintain the respective constant diameter configuration of the respective segments 11, 12, 13. The upper supporting frames 101 of the pipe bodies 11, 12 and 13 are arranged in a plurality of spaced mode, so that the pipe bodies 11, 12 and 13 have good bending performance.
Preferably, a rear release member 105 is also provided on the proximal tube 11 for rear release of the proximal end of the stent graft 100. The rear release member 105 is a radially contractible annular structure fixed to the cover film 102 and projects in a proximal direction beyond the proximal edge of the cover film 102. The structure of the rear release member 105 is the same as that of the support frame 101, but only a part of the rear release member 105 is attached to the cover film 102.
Further, the rear release member 105 is preferably also provided with barbs (not shown) protruding in the circumferential direction. The barbs may be provided in plurality. After the stent graft 100 is released, the barbs may penetrate into the body vessel to increase the stability of the stent graft 100 after release.
The proximal end of the stent graft 102 is provided with a plurality of visualization marks 106 near the edges for better visualization of the location of release of the stent graft 100 during surgery. In this embodiment, the developing mark 106 has a circular ring or 8-shaped structure, and is fixed to the cover film 102 by sewing or hot pressing. The development mark 106 is made of a radiopaque material including, but not limited to, gold, platinum, palladium, rhodium, tantalum, or alloys or composites of these metals, such as platinum, for example, alloys of platinum tungsten, platinum iridium, and the like.
Referring to fig. 1 to 3, the outer branch 2 is cantilevered from the bracket body 1, has one end connected to a side wall of the intermediate pipe body 12, and has an inner opening 21 on the side wall of the intermediate pipe body 12. The outer branch 2 extends from the inner opening 21 in a direction away from the intermediate pipe body 12.
The outer branch 2 may be of equal or unequal diameter tubular construction. In this embodiment, the outer branch 2 includes a tubular film 22 and a plurality of support rings 23 fixed to the surface of the film 22, the plurality of support rings 23 being arranged at intervals along the axial direction of the outer branch 2. The support rings 23 have the same structural form as the support frame 101 of the support body 1, and are also ring-shaped structures that can be radially contracted or expanded. The film 22 may be formed of any suitable film-covering material including, but not limited to, low porosity woven or knitted polyester, dacron material, expanded polytetrafluoroethylene, polyurethane, silicone, ultra-high molecular weight polyethylene, or other suitable material.
In other not shown constructions, the outer branch 2 may also be in the form of a bare stent, for example a lattice-like bare stent.
The inner opening 21 of the outer branch 2 is sewed and fixed on the covering film 102 of the middle pipe body 12 and is connected with the middle pipe body 12 into a whole, and the inner cavity of the outer branch 2 is communicated with the inner cavity of the middle pipe body 12. In actual manufacturing, the covering film 102 of the middle pipe body 12 is provided with a through hole, and the outer branch 2 is correspondingly sewed at the through hole.
The length L2 of the outer branch 2 is preferably 5mm to 20mm. When the stent graft 100 is released to the treatment position, the outer branch 2 can be released into the innominate artery, and the position of the stent graft 100 can be better stabilized by the cooperation of the outer branch 2 and the innominate artery because the innominate artery is positioned at the leftmost end (i.e., the nearest end) of the aortic arch, so that the stent graft 100 is not easy to shift as a whole.
The outer branch 2 is preferably further provided with a developing member 24. As shown in fig. 3, the developing members 24 are dot-shaped, and are provided at intervals along the extending direction of the outer branch 2. In addition, a plurality of developing members 24 may be provided along the outer circumference of the inner opening 21. The developing member 24 is made of a non-transmissive material and is fixed to the film 22 by sewing or hot pressing. By means of these visualization elements 24, it is possible to observe the position of the outer branch 2 during surgery, thereby facilitating a faster introduction of the circumscribing branch stent through the outer branch 2 into the innominate artery.
Still referring to fig. 1 to 3, the first inner branch 3 is integrally located inside the bracket main body 1 and is adhered and fixed to the inner wall of the middle pipe body 12. One end of the first inner branch 3 is connected to the side wall of the intermediate pipe body 12 and has a first outer opening 31 on the side wall of the intermediate pipe body 12. The first outer opening 31 is closer to the distal end than the inner opening 21 of the outer branch 2.
The first inner branch 3, like the outer branch 2, is of tubular construction, either of equal or unequal diameter, and may be a bare stent or a stent with a membrane, which will not be described in detail here. Similarly, the covering film 102 of the middle tube body 12 is provided with a through hole corresponding to the first inner branch 3, and the first outer opening 31 of the first inner branch 3 can be sewed and fixed on the covering film 102.
The other parts of the first inner branch 3, except for the first outer opening 31, are located inside the intermediate tube body 12 and can be fixed to the inner wall of the intermediate tube body 12 by stitching or adhesive.
Preferably, the first inner branch 3 extends proximally along the wall of the intermediate tube body 12 from the first outer opening 31. In this embodiment, as shown in fig. 1, the extending direction of the first inner branch 3 substantially coincides with the axis L of the stent body 1, and the axis of the first inner branch 3 is in the same plane as the axis L of the stent body 1.
The first inner branch 3 is also provided with a plurality of developing members 32 along the extending direction thereof, and the outer periphery of the first outer opening 31 may be provided with a plurality of developing members 32. The relevant features of the developing member 32 are similar to those of the developing member 24 on the outer branch 2 and will not be repeated here.
Still referring to fig. 1-3, the second inner branch 4 is located closer to the distal end than the first inner branch 3, and the second inner branch 4 is also located entirely within the intermediate tube 12 and is fixedly attached to the inner wall of the intermediate tube 12. The second inner branch 4 has a second outer opening 41 on the side wall of the intermediate tube body 12, the second outer opening 41 being closer to the distal end than the first outer opening 31.
The second inner branch 4 extends distally along the wall of the intermediate tube body 12 from the second outer opening 41. The extending direction of the second inner branch 4 is opposite to that of the first inner branch 3, so that the situation that the blood flow inlet is blocked by the first inner branch 3 and cannot enter the blood flow can be avoided.
The second inner branch 4 is similarly provided with a plurality of developing members 42 along the extending direction thereof, and in addition, the outer periphery of the second outer opening 41 may be provided with a plurality of developing members 42. Further features of the second inner branch 4 may be referred to the first inner branch 3 and will not be described again.
The inner opening 21, the first outer opening 31 and the second outer opening 41 are arranged at intervals substantially on the same line parallel to the axis L of the holder main body 1 as viewed in fig. 1. It will be appreciated that the three may be circumferentially spaced apart.
Based on the above description of the structure of the stent graft 100, and in conjunction with fig. 4, the stent graft 100, in use, is implanted into the aorta 600 via a delivery device to reestablish the blood flow path of the aorta 600. Wherein, the proximal tube 11 of the stent body 1 extends into the ascending aorta 601 side of the aorta 600 and is attached to the vessel wall of the ascending aorta 601, the distal tube 13 is located on the descending aorta 603 side of the aorta 600 and is attached to the vessel wall of the descending aorta 603, and the intermediate tube 12 is located at the aortic arch 602 of the aorta 600. The outer branch 2 extends into the innominate artery 700 to stabilize the position of the stent graft 100 within the aorta 600, making the stent graft 100 entirely less prone to displacement.
For the three branch vessels of the aortic arch 600, an appropriate external branch stent can be selected, and then the branch vessels can be respectively guided into the corresponding branch vessels through the stent graft 100.
Specifically, the first branch stent 200 extends from within the outer branch 2 into the innominate artery 700, reestablishing a blood flow path between the aorta 600 and the innominate artery 700. The second branch stent 300 extends from within the first inner branch 3 through the first outer opening 31 and into the left common carotid artery 800, reestablishing the blood flow path between the aorta 600 and the left common carotid artery 800. The third branch stent 400 extends from within the second inner branch 4 through the second outer opening 41 and into the left subclavian artery 900, reestablishing the blood flow path between the aorta 600 and the left subclavian artery 900.
The implantation process is generally as follows:
1. Firstly, releasing the proximal tube body 11 of the covered stent 100;
2. continuing to release the proximal portion of the intermediate tube 12, embedding a pre-set guidewire in the outer branch 2, and after the pre-set guidewire in the outer branch 2 is released, feeding the guidewire into the innominate artery 700 with a catcher or other instrument, and feeding the outer branch 2 into the innominate artery 700;
3. Quick release of the rest of the stent body 1 and completion of the post release member 105 of the proximal tubular body 11, anchors the stent graft 100 within the aorta 600;
4. The innominate artery 700, the left common carotid artery 800 and the left subclavian artery 900 are sequentially reconstructed by a guide wire and catheter exchange technology, and the branch stents 200, 300 and 400 with corresponding specifications are respectively released, specifically, the first branch stent 200 is released in the outer branch 2 to reconstruct the innominate artery 700, the second branch stent 300 is released in the first inner branch 3 to reconstruct the left common carotid artery 800, and the third branch stent 400 is released in the second inner branch 4 to reconstruct the left subclavian artery 900.
As can be seen from the above description, in the stent graft 100 of the present embodiment, the outer branch 2, the first inner branch 3 and the second inner branch 4 are integrally formed on the stent main body 1, these branches 2, 3, 4 can respectively provide positioning and supporting functions for the three externally connected branch stents 200, 300, 400, and these branches 2, 3, 4 are located at the middle tube body 12 with smaller tube diameter of the stent main body 1, and due to the formation of the concave portion 103 at the middle tube body 12, accordingly, a certain gap is formed between the concave portion 103 and the vessel wall of the aortic arch 602, which can provide sufficient operation space for the guide wire and catheter during the endoluminal treatment, so that the three externally connected branch stents 200, 300, 400 can be quickly fed into the branch arteries during the operation to reconstruct the three main branch arterial blood flow channels of the aortic arch 600. Meanwhile, due to the smaller diameter of the middle tube body 12, after the branch stents 200, 300 and 400 are implanted into the blood vessel, the covered stent 100 can not be extruded to the branch blood vessel to cause the blockage of the branch blood vessel. The branch stents 200, 300, 400 are anchored with the stent graft 100 by the outer branch 2, the first inner branch 3 and the second inner branch 4, respectively, so that the operation is simpler and the operation process is shortened.
In particular, among the plurality of branches 2, 3, 4 of the stent graft 100, the most proximal branch is the outer branch 2 overhanging the outside of the stent body 1, and when the stent graft 100 is delivered to a predetermined position of the aorta 600, the outer branch 2 can be extended into the innominate artery 700, thereby facilitating the determination of whether the stent graft 100 is delivered in place, and simultaneously, after the outer branch 2 is released, the stent graft 100 is not easily displaced as a whole due to the cooperation of the outer branch 2 with the innominate artery 700 and the stent body 1 with the aorta 600, thereby facilitating the implantation of the subsequent branch stents. The two inner branches 3 and 4 located at the far ends of the outer branch 2 are located inside the stent main body 1, the two inner branches 3 and 4 do not exceed the stent main body 1, but only the outer openings 31 and 41 are exposed on the side wall of the stent main body 1, and the operation space provided by the concave part 103 is matched, so that a larger position adjustment space can be provided when the branched stent is implanted into the branched arterial vessel through the inner branches 3 and 4, the branched arterial vessel can be implanted more conveniently, and the inner branches 3 and 4 do not need to be accurately opposite to the inlet of the branched arterial vessel, so that the covered stent 100 has wider applicability and higher universality.
In addition, in the present embodiment, the first inner branch 3 relatively close to the outer branch 2 is an antegrade inner branch, and the blood flow direction therein is consistent with the blood flow direction of the aorta 600, so that thrombus is not easily formed.
Further, the extending direction of the second inner branch 4 is opposite to the extending direction of the first inner branch 3, so that the situation that the blood flow inlet is blocked by the first inner branch 3 and cannot enter the blood flow can be avoided. Wherein, since the second inner branch 4 is close to the descending aorta 603 in use, the extending direction of the second inner branch 4 is consistent with the extending direction of the descending aorta 603, and the distal extending of the second inner branch 4 does not influence the inflow of blood into the second inner branch.
In the second embodiment, please refer to the structure shown in fig. 5.
The stent graft 100a of the present embodiment is mainly different from the first embodiment in that the extending direction of the first inner branch 3a is different.
As shown in fig. 5, in the present embodiment, the first inner branch 3a still extends proximally from the first outer opening 31a, but with the extension in the proximal direction, the first inner branch 3a also extends from the first outer opening 31a along the circumferential direction of the stent body 1 a.
The extended shape of the first inner branch 3a inside the stent body 1a can be regarded as a shape of a small spiral in general. An included angle alpha is formed between the plane of the axis of the first inner branch 3a and the axis L of the bracket main body 1a, and the included angle alpha is larger than 0 degrees and smaller than 90 degrees.
According to the extension mode of the first inner branch 3a, when the extension length of the first inner branch 3a is long, the inner opening 21a of the outer branch 2a is not blocked, so that the aortic blood flow can smoothly enter the outer branch 2a through the inner opening 21a and then enter the innominate artery. On the other hand, when the branch stent is inserted into the outer branch 2a, the branch stent extends to a certain length toward the inner wall of the stent body 1a as an anchoring area, and by the arrangement that the first inner branch 3a extends obliquely with respect to the axis L of the stent body 1a, the mutual interference of the branch stent inserted into the outer branch 2a and the first inner branch 3a can be avoided.
In the stent graft 100a of the present embodiment, the arrangement and structure of the stent body 1a, the outer branch 2a and the second inner branch 4a are the same as those of the first embodiment, and the description will not be repeated.
In the third embodiment, please refer to the structure shown in fig. 6.
The stent graft 100b of the present embodiment is different from the second embodiment in that the developing member 32b of the first inner branch 3b and the developing member 42b of the second inner branch 4b are each linearly extended.
As shown in fig. 6, the developing member 32b extends in the axial direction of the first inner branch 3b, and may be formed of a continuous developing wire, or continuously wound in a wire shape around the metal skeleton of the first inner branch 3 b. The developing member 42b also extends in the axial direction of the second inner branch 4 b.
The linear developing members 32b and 42b of the present embodiment have a continuous shape, and the positions of the first inner branch 3b and the second inner branch 4b can be observed more quickly when a plurality of scattered developing members are provided, as compared with the linear developing members 32 and 42 of the first embodiment.
In the fourth embodiment, please refer to the structure shown in fig. 7.
The stent graft 100c of the present embodiment is different from the second embodiment in that the extending direction of the second inner branch 4c is different.
As shown in fig. 7, the second inner branch 4c still extends distally from the second outer opening 41c, but with the extension in the distal direction, the second inner branch 4c also extends from the second outer opening 41c in the circumferential direction of the stent body 1 c.
The shape of the extension of the second inner branch 4c inside the stent body 1c can likewise be considered approximately as the shape of a small segment of a spiral. An included angle beta is formed between the plane of the axis of the second inner branch 4c and the axis L of the bracket main body 1c, and the included angle beta is larger than 0 degrees and smaller than 90 degrees.
According to the extension of the second inner branch 4c, when the stent graft 100c is implanted in the aorta, the second inner branch 4c can be positioned in the arch bending region of the aortic arch, and the second inner branch 4c can avoid the region where the stent graft 102c is stacked due to bending in a manner of being inclined with respect to the stent main body 1c axis L, thereby preventing the stent graft 102c from blocking the entrance.
In the structure shown in fig. 7, the second inner branch 4c extends in the circumferential direction in the same direction as the first inner branch 3c extends in the circumferential direction, i.e., the second inner branch 4c and the first inner branch 3c are located on the same side of the second outer opening 41c as the first outer opening 31 c. In other constructions, not shown, the second inner branch 4c may also be opposite to the direction in which the first inner branch 3c extends in the circumferential direction.
In the stent graft 100c of the present embodiment, the arrangement and structure of the stent main body 1c, the outer branch 2c and the first inner branch 3c are the same as those of the second embodiment, and the description thereof will not be repeated.
In the fifth embodiment, please refer to the structure shown in fig. 8.
The stent graft 100d of the present embodiment is different from the second embodiment in that the extending direction of the second inner branch 4d is different.
As shown in fig. 8, in the present embodiment, the second inner branch 4d extends in the proximal direction from the second outer opening 41d, and with the extension in the proximal direction, the second inner branch 4d also extends circumferentially along the stent body 1a from the second outer opening 41 d.
The shape of the extension of the second inner branch 4d inside the stent body 1d can likewise be considered approximately as the shape of a small spiral. An included angle θ is formed between the plane of the axis of the second inner branch 4d and the axis L of the bracket main body 1d, and the included angle θ is greater than 0 degrees and less than 90 degrees.
Wherein the second inner branch 4d diverges in the direction of circumferential extension from the first inner branch 3d in the direction of circumferential extension. Both of which line both sides of the first outer opening 31d and the second outer opening 41 d. The first inner branch 3d extends leftward and the second inner branch 4d extends rightward with reference to the view direction of fig. 8.
In this embodiment, the second inner branch 4d is also an antegrade branch, and coincides with the blood flow direction. The second inner branch 4d and the first inner branch 3d extend obliquely and are opposite in inclination direction, so that mutual interference can be prevented.
In the sixth embodiment, please refer to the structure shown in fig. 9.
The stent graft 100e of the present embodiment is different from the first embodiment in that the length of the outer branch 2e is shorter, and the length thereof is about 1/3 to 1/2 of the length of the outer branch 2 in the first embodiment. Only one support ring 23e is provided on the membrane 22e of the outer branch 2 e.
This embodiment provides a shorter outer branch 2e which, when implanted, provides increased flexibility to accommodate patients of different anatomy. The shorter outer branch 2e can be used as a fixed end of the external branch stent, and the position of the innominate artery is not strictly limited.
In the stent graft 100e of the present embodiment, the arrangement and structure of the stent main body 1e, the first inner branch 3e and the second inner branch 4e are the same as those of the first embodiment, and the description thereof will not be repeated.
In the seventh embodiment, please refer to the structure shown in fig. 10.
The stent graft 100f of the present embodiment is different from the first embodiment in that the outer branch 2f has a different structure.
As shown in fig. 10, in the present embodiment, the outer branch 2f has a flexible section 221f that is flexibly deformable, and the flexible section 221f extends outwardly from the inner opening 21 f. The flexible segment 221 is constructed of a flexible membrane material without support structures disposed thereon, and thus may be more compliant and capable of accommodating more anatomically configured patients. The flexible section 221 is approximately 2 mm-10 mm in length and does not exceed 1/2 of the total length of the outer branch 2 f.
The flexible section 221f may be formed by not providing the support ring 23f in a length range of the film 22f near the holder main body 1f. That is, the film 22f of the outer branch 2f is not provided with the support ring 23f within a range of about 2mm to 10mm from the inner opening 21f, and the flexible section 221f is formed by the section of the film 22f not provided with the support ring 23 f. A support ring 23f is further provided on the portion of the film 22f other than the flexible section 221f to keep the outer branch 2f tubular.
In the stent graft 100f of the present embodiment, the arrangement and structure of the stent main body 1f, the first inner branch 3f and the second inner branch 4f are the same as those of the first embodiment, and the description thereof will not be repeated.
In the above embodiments, the stent body is provided with two inner branches, so that three branch arterial vessels of the aorta can be reconstructed in combination with the arrangement of the outer branches. It will be appreciated that in some embodiments, not shown, the number of internal branches may also be reduced to one, thereby accommodating situations in which two branch arteries need to be reconstructed.
As can be seen from the specific description of the above embodiments, the stent graft of the present invention can make the main artery stent and the external branch artery stent have independent structures, and is suitable for various normal and varied blood vessels, and can respectively select the main artery stent blood vessel and the branch artery stent blood vessel with proper sizes according to the specific conditions of lesions, so as to combine into a set of stent blood vessel system which is most suitable for patients, avoid customizing the stent, and have the effects of mass production, effective time saving and easy operation.
While the invention has been described with reference to several exemplary embodiments, it is to be understood that the terminology used is intended to be in the nature of words of description and of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.