CN217338975U - Covered stent and stent component - Google Patents

Abstract

The utility model provides a covered stent and a stent component, wherein the covered stent comprises a first segment and two second segments which are respectively arranged at the two axial ends of the first segment; the stent graft comprises a bare stent and a stent graft, the bare stent comprises a helical structure, the helical structure extends from one second section to the other second section through the first section, and the lead angle of the helical structure at the first section is larger than that at the second section; the film is coated on the circumferential surface of the bare stent. The covered stent is applied to a stent component to serve as a branch stent and is used for treating pathological changes affecting the aortic arch, can well adapt to the anatomical structure of the aortic arch, and improves the treatment effect.

Description

Covered stent and stent component

Technical Field

The utility model relates to the technical field of medical equipment, concretely relates to tectorial membrane support and bracket component.

Background

Aortic dissection aneurysm is a vascular disease, generally caused by hypertension, connective tissue genetic diseases, certain congenital cardiovascular diseases such as aortic stenosis or aortic bivalvularization, pregnancy, severe trauma, heavy physical labor and certain drugs. The treatment method of aortic dissection hemangioma comprises drug treatment, open surgery treatment or interventional therapy, wherein the interventional therapy mainly refers to percutaneous covered stent implantation, and is the first treatment method of Stanford type B aortic dissection hemangioma.

For aortic aneurysm or aortic dissection with pathological changes not affecting aortic arch, interventional therapy can be carried out simply through a straight-tube aortic stent graft. However, for the pathological changes involving the aortic arch, the problem of covering the branch vessels on the aortic arch exists when only the straight tube type covered stent is used for isolating the pathological changes. The aorta includes ascending aorta, aortic arch and descending aorta that connect gradually, along ascending aorta to descending aorta's direction, three important branch arteries of Innominate Artery (IA), Left Common Carotid Artery (LCCA) and Left Subclavian Artery (LSA) have connected gradually on the aortic arch, if innominate artery or left common carotid artery are directly covered and will lead to the patient to die, consequently, the treatment of the pathological change that affects the aortic arch usually adopts the main support that reserves the interface with branch artery intercommunication, through set up branch support at the interface, and partly put branch artery into with branch support, make aorta and branch artery intercommunication. However, in the prior art, a branch stent specially used for the interface connection with the main stent is not provided, and a common covered stent is generally adopted for the interface connection, but the flexibility of the common covered stent is often difficult to meet the requirement, so that the branch stent is difficult to enter a branch artery.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a covered stent and bracket component, covered stent can use with the main support cooperation of seting up the interface and be used to treat the pathological change of the aortic arch of reaching, and this covered stent can get into the branch artery smoothly.

In order to achieve the above object, the present invention provides a stent graft, comprising a first segment and two second segments respectively disposed at both axial ends of the first segment; the stent graft comprises a bare stent and a stent graft, the bare stent comprises a helical structure, the helical structure extends from one second section to the other second section through the first section, and the lead angle of the helical structure at the first section is larger than that at the second section; the film is coated on the circumferential surface of the bare stent.

Optionally, the first segment includes a main body portion and two transition portions respectively disposed at two axial ends of the main body portion, and one end of the transition portion, which is far away from the main body portion, is connected to the second segment; the helix has a lead angle at the main portion that is greater than a lead angle at the transition portion.

Optionally, the lead angle of the helical structure at the second segment is 3 ° to 9 °, the lead angle of the helical structure at the transition portion is 4 ° to 12 °, and the lead angle of the helical structure at the main body portion is 5 ° to 14 °.

Optionally, the bare stent comprises a plurality of stent rods, and the plurality of stent rods are sequentially connected to make the bare stent in a wave shape surrounding the axis of the covered stent; each spiral turn of the spiral structure is provided with a first wave crest and a first wave trough which are sequentially arranged at intervals in the circumferential direction; the length of the spiral coil at the first section in the axial direction of the covered stent is L1, the distance between two first wave troughs adjacent in the circumferential direction is L2, and the ratio of L1 to L2 is 1: 0.8-1: 0.5.

Optionally, the helical structure has opposite proximal and distal ends; the bare stent further comprises two wave rings, one wave ring is connected with the proximal end, and the other wave ring is connected with the distal end;

the wave ring is provided with second wave crests and second wave troughs which are arranged at intervals in the circumferential direction, all the second wave troughs of the wave ring connected with the proximal end portion are located on the same circumference, and all the second wave crests of the wave ring connected with the distal end portion are located on the same circumference.

Optionally, the distance between two circumferentially adjacent second wave troughs is L3, the axial length of the wave ring is L4, and the ratio of L3 to L4 is 1: 1-1: 0.6.

Optionally, the distance between two adjacent spiral turns of the spiral structure located on the second segment is 0-8 mm, and the distance between the wave turn and the spiral turn adjacent to the wave turn is 3-8 mm.

Optionally, the distance between two circumferentially adjacent second wave troughs is L3, the length of the helical turn at the second segment in the axial direction of the stent graft is L5, and the ratio of L3 to L5 is 1: 0.7-1: 0.4.

Optionally, the stent graft has a uniform radial dimension throughout the axial length; alternatively, the radial dimension of the first segment of the stent-graft increases gradually in a direction from one of the second segments to the other of the second segments.

Optionally, the stent graft further comprises a plurality of developing elements, the plurality of developing elements being disposed on two of the second segments, respectively.

Optionally, the developing elements are divided into four developing element groups, every two developing element groups are arranged on one second section at intervals along the axial direction of the covered stent, and the axial distance between two developing element groups on the same second section is 3-10 mm.

Optionally, the developing element group comprises a strip-shaped developing structure, and the strip-shaped developing structure extends along the circumferential direction of the covered stent; the strip-shaped developing structures of different developing element groups on the same second section have different widths.

Optionally, pores are arranged on the covering film, and the pore diameter of each pore is 5-50 um.

In order to achieve the above object, the present invention further provides a stent assembly, comprising a main stent, a first branch stent and a second branch stent, wherein the second branch stent is a covered stent as described in any one of the previous items; a collapse area, a first interface, a second interface and a third interface are formed on the main body support, the first interface, the second interface and the third interface are sequentially arranged along the axial direction of the main body support, the first interface is arranged in an area outside the collapse area, and the first branch support is arranged at the first interface; the collapse zone has two axially opposite sides, the second interface and the third interface are both disposed in the collapse zone, and the second interface is disposed on the side near the first interface, the second interface is used for coupling with one of the second sections of the second branch stent.

Optionally, the second interface comprises a fenestration disposed on the side and an inline mount disposed within the fenestration; the two second sections of the covered stent are respectively a proximal second section and a distal second section, the proximal second section is used for being coupled with the second interface, the outer diameter of the proximal second section is 110% -120% of the inner diameter of the embedded stent, and the length of the proximal second section is 1-2 times of the length of the embedded stent.

In order to achieve the above object, the present invention further provides a bracket assembly, which comprises a main body bracket, a first branch bracket, a second branch bracket and a third branch bracket, wherein the second branch bracket and the third branch bracket are both the film covered brackets as described above; a collapse area, a first interface, a second interface and a third interface are formed on the main body support, and the first branch support is arranged at the first interface; the collapse zone has two opposite sides, the second interface and the third interface are respectively disposed on the two sides, and the second interface is used for being coupled with one of the second sections of the second branch stent, and the third interface is used for being coupled with one of the second sections of the third branch stent.

Optionally, the second interface and the third interface each include a fenestration disposed on the respective side and an inset bracket disposed within the fenestration; the two second sections of the stent graft are a proximal second section and a distal second section, respectively, the proximal second section of the second stent graft is configured to couple with the second interface, and the outer diameter of the proximal second section of the second stent graft is 110% to 120% of the inner diameter of the embedded stent graft in the second interface, the length of the proximal second section of the second stent graft is 1 to 2 times the length of the embedded stent graft in the second interface, the outer diameter of the proximal second section of the third stent graft is 110% to 120% of the inner diameter of the embedded stent graft in the third interface, and the length of the proximal second section of the third stent graft is 1 to 2 times the length of the embedded stent graft in the third interface.

Compared with the prior art, the utility model discloses a tectorial membrane support and bracket component has following advantage:

the tectorial stent comprises a first section and two second sections which are respectively arranged at the two axial ends of the first section; the stent graft comprises a bare stent and a stent graft, the bare stent comprises a helical structure, the helical structure extends from one second section to the other second section through the first section, and the lead angle of the helical structure at the first section is larger than that at the second section; the film is coated on the circumferential surface of the bare stent. The stent graft can be applied to a stent component for treating a lesion involving an aortic arch, the stent component can include a main stent body, a first branch stent and a second branch stent, the second branch stent body is the stent graft, a collapse area, a first interface, a second interface and a third interface are formed on the main stent body, the first interface is provided with the first branch stent, the collapse area has two opposite side surfaces, the second interface and the third interface are arranged in the collapse area, the second interface is arranged on one side surface, the second interface is used for being connected with one second section of the second branch stent, in this case, the second branch stent needs to be bent to enter a branch vessel, and the first section is easier to bend due to the larger ascending angle of the first section, so that the second branch stent can be well adapted to the anatomy of the aortic arch and the branch vessel to facilitate the entry of the other second section of the second branch stent into the branch vessel.

Or, the stent component includes a main stent, a first branch stent, a second branch stent and a third branch stent, the second branch stent and the third branch stent are both the stent-graft, and a collapse area, a first interface, a second interface and a third interface are formed on the main stent, the first interface is disposed on the first branch stent, the collapse area has two opposite side surfaces, the second interface and the third interface are respectively located on the two side surfaces, the second interface is used for connecting with a second segment of the second branch stent, the third interface is used for connecting with a second segment of the third branch stent, that is, the second branch stent and the third branch stent both need to be bent to enter into the corresponding branch vessel, because the angle of the rise of the first segment is larger, the first section is therefore easier to bend, so that the second branch stent and the third branch stent can adapt well to the anatomy of the aortic arch and the branch vessels, and so that the other second section of the second branch stent and the other second section of the third branch stent smoothly enter the respective branch vessels.

Drawings

The accompanying drawings are included to provide a better understanding of the present invention and are not intended to constitute an undue limitation on the invention. Wherein:

FIG. 1 is a schematic structural view of a stent graft according to one embodiment of the present invention, illustrating a uniform radial dimension along the entire axial length of the stent graft;

fig. 2 is a schematic structural view of a main body bracket and a first branch bracket of a bracket branch assembly according to an embodiment of the present invention;

fig. 3a to 3c are schematic views illustrating an application scenario of the stent assembly according to an embodiment of the present invention, in which fig. 3a illustrates a main stent released to an aortic arch and a first branch stent partially implanted in a innominate artery, fig. 3b illustrates a conveyor conveying a second branch stent, fig. 3c illustrates a second segment of the second branch stent coupled to a second interface and another second segment released to a left common carotid artery;

fig. 4 is a schematic view of an application scenario of a bracket assembly provided in accordance with another embodiment of the present invention;

FIG. 5 is a schematic view of a first segment of a stent graft according to one embodiment of the present invention;

FIG. 6 is a schematic view of a partially expanded plan view of a bare stent of a stent graft provided in accordance with an embodiment of the present invention during preparation;

FIG. 7 is a schematic view of a second section of a stent graft according to an embodiment of the present invention, wherein all second troughs of the wave turns are on the same circumference, but all second peaks of the wave turns are arranged helically around the axis of the stent graft;

FIG. 8 is a schematic view of a second segment of a stent graft according to an embodiment of the present invention, showing all of the second troughs of the wave ring on the same circumference, and all of the second peaks of the wave ring on the same circumference;

FIG. 9 is a schematic structural view of a stent graft according to an embodiment of the present invention, showing a first segment having a radial dimension that increases in a direction from one second segment to another;

FIG. 10 is a schematic structural view of a stent graft according to an embodiment of the present invention, showing two developing element sets on each second segment, and the developing elements in each developing element set extending along the extending direction of the corresponding support rod;

fig. 11 is a schematic structural diagram of a stent graft according to an embodiment of the present invention, showing two developing element sets on each second segment, and a strip-shaped developing structure in each developing element set, and the strip-shaped developing structure extends along the circumferential direction of the stent graft.

[ reference numerals are described below ]:

100-a covered stent, 110-a first segment, 111-a body portion, 112-a transition portion, 120-a second segment, 120 a-a proximal second segment, 120 b-a distal second segment, 101-a bare stent, 102-a covered membrane, 103-a helical structure, 103 a-a first peak, 103 b-a first trough, 104-a loop, 104 a-a proximal loop, 104 b-a distal loop, 104 c-a second peak, 104 d-a second trough, 105-a development element;

200-main body support, 201-recessed area, 202-first interface, 203-second interface, 204-third interface, 205-embedded support;

300-a first branch stent;

1 a-a first positioning needle, 1 b-a second positioning needle, 1 c-a third positioning needle, 1 d-a fourth positioning needle, 1 e-a fifth positioning needle, and 1 f-a sixth positioning needle.

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein. The present invention can also be implemented or applied through other different specific embodiments, and various details in the present specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the invention in a schematic manner, and only the components related to the invention are shown in the drawings rather than being drawn according to the number, shape and size of the components in actual implementation, and the form, quantity and proportion of the components in actual implementation may be changed at will, and the layout of the components may be more complicated.

Furthermore, each embodiment described below has one or more technical features, and this does not mean that all the technical features in any embodiment need to be implemented simultaneously by using the present invention, or that only some or all the technical features in different embodiments can be implemented separately. In other words, in the implementation of the present invention, based on the disclosure of the present invention, and depending on design specifications or implementation requirements, a person skilled in the art can selectively implement some or all of the technical features of any embodiment, or selectively implement a combination of some or all of the technical features of a plurality of embodiments, thereby increasing the flexibility in implementing the present invention.

As used in this specification, the singular forms "a", "an" and "the" include plural referents and the plural forms "a plurality" includes more than two referents unless the content clearly dictates otherwise. As used in this specification, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise, and the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either fixedly connected, detachably connected, or integrally connected. Either mechanically or electrically. Either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

To make the objects, advantages and features of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings. It should be noted that the drawings are in simplified form and are not to precise scale, and are provided for convenience and clarity in order to facilitate the description of the embodiments of the present invention. The same or similar reference numbers in the drawings identify the same or similar elements.

FIG. 1 is a schematic view of a stent graft 100 according to an embodiment of the present invention. As shown in fig. 1, the stent graft 100 includes a first segment 110 and two second segments 120 respectively disposed at both axial ends of the first segment 110. The stent graft 100 includes a bare stent 101 and a graft 102. The bare stent 101 comprises a helical structure 103, the helical structure 103 extending from one of the second segments 120 to the other of the second segments 120 via the first segment 110, i.e. the helical structure 103 comprises three portions, one of which is located on one of the second segments 120, another of which is located on the first segment 110, and yet another of which is located on the other of the second segments 120. The helix 103 has a larger lead angle at the first segment 110 than at the second segment 120. The coating film 102 is coated on the circumferential surface of the bare stent 101.

The stent graft 100 is applied to a stent assembly for treating a lesion involving the aortic arch, such as an aortic aneurysm, aortic dissection, etc. As shown in FIG. 2, in an alternative embodiment, the stent assembly further comprises a main stent 200, a first branch stent 300 and a second branch stent, and the second branch stent is the stent graft 100. A collapse area 201, a first interface 202, a second interface 203 and a third interface 204 are formed on the main body support 200, and the first interface 202, the second interface 203 and the third interface 204 are sequentially arranged along the axial direction of the main body support 200. The first interface 202 is located in the area outside the collapse zone 201, and the first branch support 300 is disposed at the first interface 202. The collapse zone 201 has two opposite sides in the axial direction of the main body support 200, the second port 203 and the third port 204 are both disposed in the collapse zone 201, and the second port 203 is disposed on the side near the first port 202, the second port 203 is used for coupling with one of the second segments 120 of the second branch support (i.e., the stent-graft 100). In embodiments of the present invention, the two second segments 120 of the stent graft 100 are referred to as a proximal second segment 120a and a distal second segment 120b, respectively, and the second interface 203 is configured to couple with the proximal second segment 120a of the second stent graft. Here, the proximal end and the distal end are defined relative to the heart, and the end of the medical device close to the heart in actual use is taken as the proximal end, and the end far from the heart is taken as the distal end.

The stent assembly can be used to treat a lesion in a vessel wall between the unknown artery and the left common carotid artery, wherein, as shown in fig. 3c, the main stent 200 is implanted in the aorta, the distal end of the first branch stent 300 is implanted in the unknown artery, the distal second segment 120b of the second branch stent (i.e., the covered stent 100) is implanted in the left common carotid artery, and the recessed area 201 also covers the left subclavian artery, so that blood flow can flow from the lumen of the main stent 200 through the first branch stent 300 into the unknown artery, from the second branch stent into the left common carotid artery, and from the third port 204 through the recessed area 201 into the left subclavian artery, thereby isolating the lesion and ensuring blood flow of the three branch arteries. In other cases, the stent assembly may also be used to treat a condition where the lesion involves the wall of the blood vessel between the left common carotid artery and the left subclavian artery, such that the recessed region 201 covers the innominate artery, the distal end of the first branch vessel 300 is implanted into the left subclavian artery, and the distal second segment 120b of the second branch stent is implanted into the left common carotid artery, such that blood flows through the recessed region 201 from the third port 204 into the innominate artery, from the second branch stent into the left common carotid artery, and from the first branch stent 300 into the left subclavian artery.

In another alternative embodiment, the stent assembly is capable of treating conditions where the lesion affects both the vessel wall between the innominate artery and the left common carotid artery, and the vessel wall between the left common carotid artery and the left subclavian artery. In this embodiment, the stent assembly further comprises a third branch vessel, which is also the stent graft 100, and the second interface 203 and the third interface 204 are respectively located on two sides of the recessed area 201, and the third interface 204 is used for coupling with the third branch stent, i.e. the proximal second segment 120a of another stent graft 100. When the stent assembly is implanted in a patient, as shown in fig. 4, the main stent 200 is implanted in the aorta, the distal end of the first branch stent 300 is implanted in the innominate artery, the distal second segment 120b of the second branch stent (i.e., the stent graft 100) is implanted in the left common carotid artery, and the distal second segment 120b of the third branch stent (i.e., the stent graft 100) is implanted in the left subclavian artery. It is understood that, in fig. 4, the first branch stent 300, the second branch stent and the third branch stent are illustrated as being sequentially arranged along the axial direction of the main body stent 200, in an alternative implementation, the first port 202 may also be disposed in the recessed area 201 between the second port 203 and the third port 204, in which case, the distal end of the first branch stent 300 is used for implanting the left common carotid artery, and the distal second section 120b of the second branch stent and the distal second section 120b of the third branch stent are used for implanting the innominate artery and the left subclavian artery, respectively.

As described above, in actual use, the proximal axis and the distal axis of the second branch stent and the third branch stent (when the third branch stent exists) are arranged at an angle, that is, the second branch stent and the third branch stent are bent. The embodiment of the utility model provides a covered stent 100 naked support 101 includes helical structure 103, just helical structure 103 is in the lead angle of first section 110 department is greater than it is in the lead angle of second section 120 department, consequently covered stent 100 first section 110's compliance is better, and consequently the condition of bending more easily, and not taking place to discount makes covered stent 100 conduct second branch support or during the third branch support, can adapt to the anatomical form of aortic arch better and crooked, and then make the second branch support far end second section 120b and the third branch support far end second section 120b can smoothly get into corresponding branch vessel. Meanwhile, the lift angle of the second segment 120 is smaller than that of the first segment 110, so that the compliance of the second segment 120 is weakened, the second branch stent and the proximal second segment 120a of the third branch stent are effectively connected with corresponding interfaces, the internal leakage and the slippage are avoided, and the distal second segment 120b of the second branch stent and the distal second segment 120b of the third branch stent are tightly abutted with the vessel wall of the corresponding branch artery and the main stent 200, so that the internal leakage is avoided.

As shown in fig. 5, the first segment 110 preferably includes a main body portion 111 and two transition portions 112 respectively disposed at two axial ends of the main body portion 111, and one end of each transition portion 112, which is far away from the main body portion 111, is connected to one of the second segments 120. The helix 103 has a larger lead angle at the body portion 111 than at the transition portion 112. That is, the lead angle of the helical structure 103 at the main body portion 111, the lead angle at the transition portion 112, and the lead angle at the second segment 120 are sequentially decreased, so that the compliances of the main body portion 111, the transition portion 112, and the second segment 120 are sequentially weakened. More specifically, in the present embodiment, referring to fig. 5 to 8, an angle α 1 of a lead angle of the spiral structure 103 at the main body portion 111 is 5 ° to 14 °, an angle α 2 of a lead angle of the spiral structure 103 at the transition portion 112 is 4 ° to 12 °, an angle α 3 of a lead angle of the spiral structure 103 at the second segment 120 is 3 ° to 9 °, and α 1> α 2> α 3.

As will be understood by those skilled in the art, the bare stent 101 comprises a plurality of stent rods (not labeled), and the plurality of stent rods are connected in sequence, so that the bare stent 101 has a wave shape around the axis of the stent graft 100, and thus, the helical coil 103 has first wave crests 103a and first wave troughs 103b (shown in FIG. 1) alternately arranged in sequence in the circumferential direction. This may be advantageous to facilitate radial compression of the stent graft 100 by external forces, thereby facilitating delivery. Preferably, referring to fig. 6, all the stent rods are made of the same strand of silk material, in other words, the bare stent 101 is braided and formed by the same strand of silk material. Further, referring to fig. 1 in combination with fig. 7 and 8, the helical structure 103 has a proximal end (not labeled) and a distal end (not labeled) opposite to each other in the axial direction of the stent graft 100, and the bare stent 101 further includes two wave rings 104, one of the wave rings 104 is connected to the proximal end to serve as a proximal wave ring 104a, and the other wave ring 104 is connected to the distal end to serve as a distal wave ring 104b, that is, each of the second segments 120 includes one wave ring 104. The wave ring 104 has second wave crests 104c and second wave troughs 104d arranged at intervals in the circumferential direction. The proximal facing apex of the wave loop 104 or the helical loop of the helical structure herein is a trough and the distal facing apex is a peak. Two of the wave turns 104 may be woven with the helical structure 103 from a single strand of wire.

When the bare stent 101 is prepared, a mold (not shown) is provided, and a positioning needle assembly is disposed on the outer peripheral surface of the mold, with reference to fig. 6, the positioning needle assembly includes a plurality of first positioning needles 1a, a plurality of second positioning needles 1b, a plurality of third positioning needles 1c, a plurality of fourth positioning needles 1d, a plurality of fifth positioning needles 1e, a plurality of sixth positioning needles 1f … …, a plurality of nth positioning needles (not shown), a plurality of nth +1 positioning needles (not shown), a plurality of nth +2 positioning needles (not shown), and a plurality of nth +3 positioning needles (not shown). Wherein a plurality of the first positioning pins 1a are arranged on the same circumference, the second positioning pins 1b are arranged at intervals from the first positioning pins 1a in the axial direction of the mold, and a plurality of the second positioning pins 1b may be arranged on another circumference. The third positioning pins 1c are located at one end of the second positioning pin 1b far away from the first positioning pin 1a, and are spirally arranged for one turn around the axis of the mold, and the fourth positioning pins 1d are located at one side of the third positioning pin 1c far away from the second positioning pin 1b, and are spirally arranged for one turn around the axis of the mold. The fifth positioning needles 1e are located on one side of the fourth positioning needle 1d far away from the third positioning needle 1c, and are spirally arranged for one circle around the axis of the mold, and the fifth positioning needles 1e and the third positioning needle 1c can be located on the same spiral line. The sixth positioning pins 1f are located on a side of the fifth positioning pin 1e away from the fourth positioning pin 1d and are arranged in a spiral around the axis of the mold in one turn, the sixth positioning pins 1f and the fourth positioning pin 1d may be located on the same spiral line … …, the nth positioning pins may be arranged in a manner similar to that of the third positioning pin 1c and the fifth positioning pin 1e, the n +1 th positioning pins may be arranged in a manner similar to that of the fourth positioning pin 1d and the sixth positioning pin 1f, the n +2 th positioning pins may be arranged on the same circumference, the n +3 th positioning pins are located on a side of the n +2 th positioning pin away from the n +1, and the n +3 th positioning pins are located on the same circumference. Next, the bare stent 101 is wound along the positioning needle assembly, specifically, the wire material is wound around the first positioning needle 1a and the second positioning needle 1b alternately, so that one wave ring 104 is obtained as a proximal wave ring 104a, and all the second wave crests 104c of the proximal wave ring 104a are located on the same circumference, and all the second wave troughs 104d are located on the same circumference (as shown in fig. 6). The wire is then alternately passed around the third and fourth locator pins 1c, 1d, resulting in a first helical turn of the helical structure 103. The wire is then passed alternately around the fifth and sixth registration pins 1e, 1f again resulting in a second spiral turn … … of the spiral structure 103, the wire is passed alternately around the nth and n +1 th registration pins resulting in the last spiral turn of the spiral structure 103, after which the wire is passed around the n +2 registration pin and the n +3 th registration pin resulting in one of the wave turns 104 as the distal wave turn 104b, all of the second wave crests of the distal wave turn 104b being at the same circumference and all of the second wave troughs being at another circumference. Alternatively, the plurality of second positioning pins 1b may be arranged in a spiral around the axis of the mold in one turn and on the same spiral line as the third positioning pin 1c, and the (n + 2) th positioning pin may be arranged in a spiral around the axis of the mold in one turn and on the same spiral line as the (n + 1) th positioning pin. As such, as shown in fig. 1 and 8, all of the second peaks 104c of the coil 104 connected to the first coil (i.e., the proximal coil 104a) are no longer on a circle.

Referring back to FIGS. 1 and 5, at the first segment 110, the length of the coil in the axial direction of the stent graft 100 is L1, the distance between two adjacent first wave troughs 103b of the same coil is L2, and the ratio of L1 to L2 is 1: 0.8-1: 0.5. The ratio of L1 to L2, in combination with the angle α 1 of the angle of ascent of the helical structure 103 at the main portion 111 of the first segment 110 and the angle α 2 of the angle of ascent of the helical structure 103 at the transition portion 112, may enable the intravascular bending angle of the first segment 110 to reach 90 ° to better accommodate the anatomy of the aorta and the branch vessels, facilitating partial entry of the stent graft 100 as the second or third branch stent into the corresponding branch vessel.

Referring back to fig. 2, the second interface 203 includes a window (not labeled) opened on the corresponding side surface and an embedded bracket 205 arranged in the window. One of the second segments 120 of the second branch stent of the present embodiment is coupled with the second interface 203, meaning that the second branch stent abuts against the inner wall of the inline stent 205 of the second interface 203 at least at the proximal undulation 104 a.

Referring to fig. 7 and 8 again, the distance between two circumferentially adjacent second wave troughs 104d of the wave ring 104 is L3, the length of the wave ring 104 in the axial direction of the stent graft 100 is L4, and the ratio of L3 to L4 is 1: 1-1: 0.6, wherein when the proximal second segment 120a of the stent graft 100 as the second branch stent is coupled with the second port 203, the proximal wave ring 104a has enough adhesive force under the condition that the outer diameter of the proximal second segment 120a is large enough, so that the proximal second segment 120a effectively abuts against the embedded stent 205 in the second port 203, the internal leakage at the second port 203 is avoided, and the detachment of the second branch stent from the main body stent 200 is avoided. Furthermore, the distal wave ring 104b can also conform to the corresponding vessel wall if the outer diameter of the distal second segment 120b is sufficiently large to avoid endoleak of the distal end of the distal segment 120b within the vessel. The outer diameter of the proximal second segment 120a is large enough, that is, the outer diameter of the second segment 120a is 110% to 120% of the inner diameter of the inner stent 205 in the second interface 203, so that the proximal second segment 120a is coupled with the inner stent 205 in an interference fit manner, and the inner diameter of the inner stent 205 may be set between 8mm to 12mm as required. The outer diameter of the distal second segment 120b is sufficient to mean that the outer diameter of the distal second segment 120b is 115% to 105% of the inner diameter of the corresponding branch artery, such that the distal second segment 120b is in interference fit with the corresponding branch artery. Furthermore, the axial length of the proximal second segment 120a is 1-2 times the length of the embedded stent 205, so as to ensure that the proximal second segment 120a has a sufficient overlapping area with the embedded stent 205 to prevent the second branch stent from being detached from the embedded stent 205, wherein the proximal end of the proximal second segment 120a may be located inside the embedded stent 205 or may protrude from the proximal end of the embedded stent 205. In this embodiment, the axial length of the stent graft 100 is 40mm to 100mm, and the axial length of the distal second segment 120b is 5mm to 20 mm.

It is to be appreciated that when the stent assembly includes the third bifurcation stent, the third interface 204 includes a fenestration provided on a respective side and an inline stent 205 positioned within the fenestration, and that coupling the proximal second segment 120a of the stent graft 100 as the third bifurcation stent to the third interface 204 means that the proximal second segment 120a of the third bifurcation stent abuts the inner wall of the inline stent 205 within the third interface 204 at least at the proximal bead 104 a. Thus, the ratio of L3 to L4 also ranges such that when the proximal second segment 120a of the stent graft 100 as the third branch stent is coupled to the third hub 204, the proximal wave ring 104c has sufficient apposition force when the outer diameter of the proximal second segment 120a is sufficiently large to allow the proximal second segment 120a to effectively abut against the inline stent 205 in the third hub 204, to avoid endoleak at the third hub 204, and to avoid detachment of the third branch stent from the main body stent 200. And the distal wave ring 104b also conforms to the corresponding vessel wall if the outer diameter of the distal second segment 120b is sufficiently large to prevent endoleaks of the distal end of the distal segment 120b within the vessel. Here, the outer diameter of the proximal second segment 120a is large enough to mean that the outer diameter of the second segment 120a is 110% to 120% of the inner diameter of the inline stent 205 in the third port 203, and the outer diameter of the distal second segment 120b is large enough to mean that the outer diameter of the distal second segment 120b is 115% to 105% of the inner diameter of the corresponding branch artery.

In addition, referring to fig. 7, at the second segment 120, the axial distance h1 between the wave ring 104 and the adjacent helical ring is 3mm to 8mm, the axial distance h2 between two adjacent helical rings of the helical structure 103 is 0 to 8mm, the length of the helical ring adjacent to the wave ring 104 in the axial direction of the stent graft 100 is L5, and the ratio of L3 to L5 is 1: 0.7-1: 0.4. This provides the advantage that the proximal second segment 120a can engage the inner stent 205 and the distal second segment 120b can engage the corresponding branch vessel, avoiding endoleaks. In addition, the specific ratio of L3 to L5 also increases the radial support force of the second segment 120, further improving the sealing properties of the stent graft 100.

Further, referring back to FIG. 1, in some embodiments, the stent graft 100 has a uniform radial dimension throughout its axial length such that the stent graft 100 is a hollow cylindrical structure throughout. In other embodiments, as shown in fig. 9, each of the second segments 120 has a uniform outer diameter and presents a hollow cylindrical structure, but the radial dimension of the first segment 110 gradually increases in a direction from one of the second segments 120 to the other of the second segments 120, such that the radial dimension of one of the second segments 120 is smaller than the radial dimension of the other of the second segments 120. In practical use, if the inner diameter of the branch artery is larger than the inner diameter of the second port 203, the second segment 120 with smaller radial size after expansion is used as the proximal second segment 120a of the second branch stent to be coupled with the second port 203, whereas if the inner diameter of the branch artery is smaller than the inner diameter of the second port 203, the second segment 120 with larger radial size after expansion is used as the proximal segment 120a of the second branch stent to be coupled with the second port 203. Similarly, if the stent assembly includes the third branched stent, when the inner diameter of the branched artery is larger than the inner diameter of the third interface 204, the second segment 120 with smaller radial dimension after expansion is used as the proximal second segment 120a of the third branched stent to be coupled with the third interface 204, and if the inner diameter of the branched artery is smaller than the inner diameter of the third interface 204, the second segment 120 with larger radial dimension after expansion is used as the proximal segment 120a of the third branched stent to be coupled with the third interface 204.

Further, referring to fig. 1, 10 and 11, the stent graft 100 further includes a plurality of developing elements 105, and the plurality of developing elements 105 are respectively disposed on the two second segments 120. Preferably, as shown in fig. 10 and 11, all the developing elements 105 are divided into four developing element groups, and every two developing element groups are arranged on the same second segment 120 at intervals along the axial direction of the stent graft 100, and the distance between the two developing element groups on the same second segment 120 is 3mm to 10 mm. By providing a plurality of the visualization elements 105, the position of the stent graft 100 within the patient may be identified under the influence of a visualization device, such as an X-ray instrument.

Alternatively, referring to fig. 10, in some embodiments, the developing element 105 may be a tubular member, and is disposed on the support rod and extends along the extending direction of the support rod. Alternatively, referring to fig. 11, the developing element 105 includes a strip-shaped developing structure extending along the circumferential direction of the second segment 120, and preferably extending for one turn (i.e., extending for 360 ° to form an end-to-end ring-shaped configuration). The strip-like development structures of different development element groups on the same second segment 120 have different widths so as to distinguish the development elements 105 to better identify the position of the stent graft 100 in the body. The width refers to the dimension of the strip-shaped development structure in the axial direction of the stent graft 100.

Additionally, in the embodiment of the present invention, the coating 102 is coated on the circumferential surface of the bare stent 101 includes three situations, one is that the coating 102 is only coated on the outer circumferential surface of the bare stent 101, the other is that the coating 102 is only coated on the inner circumferential surface of the bare stent 102, and the third is that the coating 102 is both coated on the inner circumferential surface of the bare stent 102 and also coated on the outer circumferential surface of the bare stent 102. In the case where the covering film 102 covers both the inner circumferential surface and the outer circumferential surface of the bare stent 102, the covering film 102 actually includes an inner covering film and an outer covering film, and in this embodiment, an adhesive is preferably provided between the inner covering film and the outer covering film to bond the two covering films. The adhesive is at least one of polyimide, polyurethane, and a perfluoroethylene-propylene copolymer, for example. In addition, the bare stent 101 may be bonded or heat-fused to the covering film 102.

Further, the coating film 102 is provided with pores, and the pore diameter of the pores is 5um to 50 um. The arrangement of the pores increases the surface roughness of the coating 102, and facilitates the endothelial cells of the blood vessel to climb when the stent graft 100 is implanted into a branch artery, thereby promoting the rapid endothelialization of the blood vessel. The material of the covering film 102 includes, but is not limited to, any one of expanded polytetrafluoroethylene (ePTFE), perfluoroethylene propylene copolymer (FEP), and Polyurethane (PU).

Further, the embodiment of the present invention also provides a stent assembly, which comprises the main body stent 200, the first branch stent 300 (the main body stent 200 and the branch stent 300 are shown in fig. 2), and a second branch stent, which is the aforementioned stent graft 100. A collapse area 201, a first interface 202, a second interface 203 and a third interface 204 are formed on the main body support, and the first interface 202, the second interface 203 and the third interface 204 are sequentially arranged along the axial direction of the main body support 200. The first interface 202 is located in the area outside the collapse zone 201, and the first branch support 300 is disposed at the first interface 202. The collapse zone 201 has two axially opposite sides, the second interface 203 and the third interface 204 are both arranged at the collapse zone 201, and the second interface 203 is arranged on the side close to the first interface 202, the second interface 203 is used for coupling with one of the second segments 120 of the second branch stent.

Furthermore, the embodiment of the present invention provides another bracket assembly, which includes the main body bracket 200, the first branch bracket 300 (the main body bracket 200 and the branch bracket 300 are shown in fig. 2), a second branch bracket and a third branch bracket, wherein the second branch bracket and the third branch bracket are both the stent graft 100 described above. The main body support is formed with a collapse area 201, a first interface 202, a second interface 203 and a third interface 204, and the first branch support 300 is arranged at the first interface 202. The collapse zone 201 has two axially opposite sides, the second interface 203 and the third interface 204 are respectively disposed on the two sides, and the second interface 203 is used for coupling with one of the second segments 120 of the second branch stent, and the third interface 204 is used for coupling with one of the second segments 120 of the third branch stent.

Although the present invention is disclosed above, it is not limited thereto. Various modifications and alterations of this invention may be made by those skilled in the art without departing from the spirit and scope of this invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (17)

1. A stent graft, comprising a first segment and two second segments disposed at both axial ends of the first segment, respectively; the stent graft comprises a bare stent and a stent graft, the bare stent comprises a helical structure, the helical structure extends from one of the second segments to the other of the second segments through the first segment, and the helix has a lead angle at the first segment that is greater than a lead angle at the second segment; the film is coated on the circumferential surface of the bare stent.

2. The stent graft as recited in claim 1, wherein the first segment comprises a main body portion and two transition portions disposed at two axial ends of the main body portion, respectively, and one end of the transition portion away from the main body portion is connected to the second segment; the helix has a lead angle at the main portion that is greater than a lead angle at the transition portion.

3. The stent graft of claim 2, wherein the helix has a lead angle at the second segment of 3 ° to 9 °, a lead angle at the transition of 4 ° to 12 °, and a lead angle at the main body of 5 ° to 14 °.

4. The stent graft of claim 1, wherein the bare stent comprises a plurality of stent rods, which are connected in sequence and make the bare stent in a wave shape surrounding the axis of the stent graft; each spiral turn of the spiral structure is provided with a first wave crest and a first wave trough which are sequentially arranged at intervals in the circumferential direction; the length of the spiral coil at the first section in the axial direction of the covered stent is L1, the distance between two first wave troughs adjacent in the circumferential direction is L2, and the ratio of L1 to L2 is 1: 0.8-1: 0.5.

5. The stent-graft of claim 1, wherein the helical structure has opposite proximal and distal ends; the bare stent further comprises two undulating rings, one undulating ring being connected to the proximal end and the other undulating ring being connected to the distal end;

the wave ring is provided with second wave crests and second wave troughs which are arranged at intervals in the circumferential direction, all the second wave troughs of the wave ring connected with the proximal end portion are located on the same circumference, and all the second wave crests of the wave ring connected with the distal end portion are located on the same circumference.

6. The stent graft as recited in claim 5, wherein the distance between two circumferentially adjacent second wave troughs is L3, the axial length of the wave ring is L4, and the ratio of L3 to L4 is 1: 1-1: 0.6.

7. The stent graft as recited in claim 5, wherein the helical structure has a distance between two adjacent helical turns of the second segment of 0-8 mm, and the wave turns have a distance between 3-8mm and the adjacent helical turns.

8. The stent graft of claim 5, wherein a distance between two circumferentially adjacent second troughs is L3, a length of the coil at the second segment in an axial direction of the stent graft is L5, and a ratio of L3 to L5 is 1: 0.7-1: 0.4.

9. The stent graft of claim 1, wherein the stent graft has a uniform radial dimension throughout the entire length in the axial direction; alternatively, the radial dimension of the first segment of the stent-graft increases gradually in a direction from one of the second segments to the other of the second segments.

10. The stent graft of claim 1, further comprising a plurality of development elements disposed on each of the two second segments.

11. The stent graft of claim 10, wherein the developing elements are divided into four developing element groups, and each two developing element groups are arranged on one second segment at intervals along the axial direction of the stent graft, and the axial distance between two developing element groups on the same second segment is 3-10 mm.

12. The stent graft of claim 11, wherein the set of development elements comprises strip-like development structures extending in a circumferential direction of the stent graft; the strip-shaped developing structures of different developing element groups on the same second section have different widths.

13. The stent graft as claimed in claim 1, wherein the stent graft is provided with pores, and the pore diameter of the pores is 5-50 um.

14. A stent assembly comprising a main body stent, a first branch stent and a second branch stent, the second branch stent being a stent graft according to any one of claims 1 to 13; a collapse area, a first interface, a second interface and a third interface are formed on the main body support, the first interface, the second interface and the third interface are sequentially arranged along the axial direction of the main body support, the first interface is arranged in an area outside the collapse area, and the first branch support is arranged at the first interface; the collapse zone has two axially opposite sides, the second and third interfaces are disposed in the collapse zone, and the second interface is disposed on the side adjacent to the first interface for coupling with one of the second segments of the second stent.

15. The bracket assembly of claim 14, wherein the second interface comprises a fenestration disposed on the side and an inset bracket disposed within the fenestration; the two second sections of the covered stent are respectively a proximal second section and a distal second section, the proximal second section is used for being coupled with the second interface, the outer diameter of the proximal second section is 110% -120% of the inner diameter of the embedded stent, and the length of the proximal second section is 1-2 times of the length of the embedded stent.

16. A stent assembly comprising a main stent, a first branch stent, a second branch stent and a third branch stent, wherein the second branch stent and the third branch stent are each the stent graft of any one of claims 1-13; a collapse area, a first interface, a second interface and a third interface are formed on the main body support, and the first branch support is arranged at the first interface; the collapse zone has two opposite sides, the second interface and the third interface are respectively arranged on the two sides, the second interface is used for being coupled with one second section of the second branch support, and the third interface is used for being coupled with one second section of the third branch support.

17. The bracket assembly of claim 16, wherein the second interface and the third interface each comprise a fenestration disposed on the respective side and a recessed bracket disposed within the fenestration; the two second sections of the stent graft are a proximal second section and a distal second section, respectively, the proximal second section of the second stent graft is configured to couple with the second interface, and the outer diameter of the proximal second section of the second stent graft is 110% to 120% of the inner diameter of the embedded stent graft in the second interface, the length of the proximal second section of the second stent graft is 1 to 2 times the length of the embedded stent graft in the second interface, the outer diameter of the proximal second section of the third stent graft is 110% to 120% of the inner diameter of the embedded stent graft in the third interface, and the length of the proximal second section of the third stent graft is 1 to 2 times the length of the embedded stent graft in the third interface.

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