CN113476175B - Vascular stent - Google Patents

Abstract

The invention discloses a vascular stent, which comprises a plurality of single-ring stents, a plurality of connecting bodies, at least one axial connecting body, a plurality of first circumferential connecting bodies and at least one second axial connecting body, wherein the single-ring stents are distributed at intervals along the axial direction, the single-ring stents extend along the circumferential direction and undulate along the axial direction, the two adjacent single-ring stents are connected through the connecting bodies, one first circumferential connecting body is connected with the peak of one single-ring stent in the circumferential direction, the other first circumferential connecting body is connected with the peak of the other single-ring stent in the circumferential direction, the axial connecting bodies are connected with the peak or the trough of the adjacent two single-ring stents or the first circumferential connecting body in the axial direction, and the axial connecting bodies are unevenly distributed in the circumferential direction. The vascular stent provided by the invention has different supporting performance and flexibility in the circumferential direction, can be better adapted to vascular anatomy structures, and has excellent bending performance and fatigue performance.

Description

Vascular stent

Technical Field

The invention relates to the technical field of biomedical engineering, in particular to a vascular stent.

Background

The thoracic aortic endoluminal prosthesis (Thoracic Endovascular Aortic Repair, TEVAR) is a treatment method for performing minimally invasive interventional therapy operation, by penetrating the femoral artery through the skin, delivering an interventional device such as a covered stent and the like to a lesion site along the femoral artery through the guidance of an imaging device, and performing local isolation on an interlayer site in a vascular cavity. The traditional Chinese medicine has the advantages of small wound, quick recovery, avoidance of some complications of surgical operation and the like, and has wide clinical application.

The aortic blood vessel presents a certain taper in the axial direction, the diameter of the blood vessel at the proximal end is larger, the diameter of the blood vessel at the distal end is smaller, a Stent-derived new rupture (Stent-Induced New Entry, SINE) possibly occurs after TEVAR operation, the SINE refers to that the straight cylindrical covered Stent is not completely matched with the tapered blood vessel morphology, after the covered Stent is inserted, the distal end of the Stent is excessively opened, larger shear stress is generated on the aortic dissection membrane, and then new tearing crack is caused. A restrictive bare stent (RESTRICTIVE BARE STENT, RBS) is usually pre-placed at the distal end of the stent graft prior to stent graft release during TEVAR procedures, thereby limiting excessive expansion of the distal end of the stent graft and preventing the occurrence of SINEs.

The existing aortic stent-graft and the limiting stent have the following defects:

1. The exposed area of the overhanging end part of the existing part covered stent can press the inner wall of the blood vessel, and the risk of rupture of the inner membrane is increased. The existing part covered stent is usually formed by stitching a plurality of stent single rings by a polymer film. The proximal end or the distal end of the covered stent can be extended with a small section of bare stent single ring for hooking the conveying system and adapting to loading, pushing and releasing of the conveying system. However, the blood vessel is peristaltic along with the beating of the heart, and when the covered stent is completely released at the lesion part, the exposed area of the covered stent, which extends outwards, can be mutually extruded with the inner wall of the blood vessel, and even the blood vessel intima of the lesion part with weakness is punctured.

2. The stent apices at both ends of the bare stent may press the inner wall of the blood vessel, increasing the risk of rupture of the intima. The two ends of the bare stent are similar to the overhanging bare section of the covered stent, and after the bare stent is completely released at the lesion part, the two ends of the bare stent can be mutually extruded with the inner wall of the blood vessel along with the peristaltic motion of the blood vessel, and even puncture the blood vessel intima of the weak lesion part.

3. The stent has a large shrinkage, i.e., the tubular stent is liable to decrease in length in its axial direction. This is often due to the poor manner in which the ring supports are connected. The reason for the shrinkage is that after the existing bracket is axially stressed, the connector is easy to reverse in the axial direction, so that the bracket is axially shrunk. And the larger the axial length of the connector is, the larger the shrinkage ratio is. The existing bracket is formed by connecting multiple independent single-ring brackets, and the connector is a metal wire or a polymer wire and the like. The silk thread is wound or knotted at the wave crest and the wave trough, so that a plurality of single-ring brackets are connected into a complete bracket. However, the silk thread nodes easily slide on the wave rod of the bracket, when the nodes slide from the wave crests and the wave troughs to the middle section of the wave rod, the bracket not only integrally shortens, but also can change in shape unpredictably, and the performance of the integral bracket is further affected.

4. The bending performance of the partially bare stent is poor. After the existing part of the bare stent is greatly bent, the bent cross section of the stent is distorted, and the cross section shape is changed from round shape to elliptical shape with acute angles. The major axis of the ellipse is larger than the inner diameter of the blood vessel at the lesion part, and the acute angle may scratch the inner wall of the blood vessel. Meanwhile, after the existing part of the bare stent is bent greatly, the small bent part can be folded inwards, the cross-sectional area is reduced, and the outer surface of the stent cannot be well attached to the inner wall of a blood vessel.

5. The current stage is dedicated to the treatment of the DebakeyII type of vascular stents, particularly for the DebakeyII type, where no branch vessel reconstruction is required and the dissection is not involved. Because the ascending aorta is short and close to the heart, to prevent the vascular stent from coming off at the site of intervention, the stent needs to have a length sufficient to span the aortic arch to complete the anchoring. If the traditional covered stent is used for interventional therapy, the high polymer film can block the blood supply of the aortic arch branch, so that the film is required to be perforated, and the accurate adaptation of the perforation and the branch blood vessel is completed, so that the operation difficulty is greatly increased.

6. And the radial supporting force of the part of the bare bracket in the axial direction is unevenly distributed, namely the radial supporting force of the single-ring bracket and the radial supporting force of the connecting body are greatly different. The supporting force of the existing bracket in the radial direction is provided by a single-ring bracket, the bending performance is provided by the connecting body wires, and the wires have almost no supporting force in the radial direction. This results in an uneven radial support force distribution of the overall support. The single ring support must possess sufficient radial supporting force to stably anchor the whole support in the blood vessel without sliding, so that the pressure generated by the single ring support on the inner wall of the blood vessel is far greater than that of the connector part, the inner wall of the blood vessel of a patient is very weak, and the single ring support generating larger pressure is very likely to damage the inner wall of the blood vessel again.

7. The mechanical performance specification of the existing part of bare bracket is single. According to the structural design and manufacturing technology of the existing partial bracket, only the mechanical properties of the single-ring bracket can be adjusted, and the mechanical properties of the single-ring bracket mainly depend on the two parts of the size of the wave rod section and the performance of the manufacturing material. The size and specification of the cross section of the wave rod are fixed, and the mechanical properties of the material are required to be debugged through a complex process, so that the support with different mechanical properties is difficult to produce based on the structural design and manufacturing technology of the existing support.

8. The existing part of bare stent is easy to generate the phenomena of eccentricity, collapse and the like of the stent ring. After the implantation, the probability of faults such as separation, fracture, dislocation and the like of the stent ring is as high as 9.2%, and particularly the phenomena such as eccentricity, collapse and the like of the bare stent extending to the abdominal aorta part are very easy to occur, which is caused by the lack of radial supporting force and the lack of axial supporting objects of the stent.

Disclosure of Invention

In view of the above-described drawbacks of the prior art, an object of the present invention is to provide a vascular stent having different supporting properties and compliance in the circumferential direction, which can better adapt to the vascular anatomy, while having excellent bending properties and fatigue properties.

To achieve the above and other related objects, the present invention provides a vascular stent, a plurality of single ring stents are arranged at intervals along an axial direction, and the single ring stents undulate along the axial direction while extending along a circumferential direction;

the two adjacent single-ring brackets are connected through the connectors;

the connecting body comprises two first circumferential connecting bodies and at least one axial connecting body;

one first circumferential connector is connected with the wave crest of one single-ring bracket in the circumferential direction, and the other first circumferential connector is connected with the wave trough of the other single-ring bracket in the circumferential direction;

the axial connectors are axially connected with peaks or troughs of two adjacent single-ring brackets or the first circumferential connectors, and the axial connectors are unevenly distributed in the circumferential direction.

In an alternative embodiment of the present invention, the material of the single ring support is a shape memory alloy.

In an alternative embodiment of the present invention, the single loop stent comprises a peak, a trough, and a wave rod connecting the peak and the trough, the wave rod being tangential or non-tangential to the peak/trough.

In an alternative embodiment of the present invention, the relative positions of the single ring stents of the vascular stent are the same or different.

In an alternative embodiment of the present invention, the material of the connector is a shape memory alloy.

In an alternative embodiment of the present invention, the connector is in a grid form.

In an alternative embodiment of the invention, the vascular stent further comprises a cover attached to the single ring stent or the connector.

In an alternative embodiment of the present invention, the first circumferential connector is annular, and the first circumferential connector is connected to the trough/crest of the single ring bracket in a winding manner.

In an alternative embodiment of the invention, the vascular stent further comprises a second circumferential connector circumferentially wound around the axial connector.

In an alternative embodiment of the present invention, the first circumferential connector is a single-stranded wire or a multi-stranded twisted wire, and the second circumferential connector is a single-stranded wire or a multi-stranded twisted wire.

In an alternative embodiment of the present invention, the first circumferential connector includes a first knot, and the first knot is a knot wound around a peak or a trough of the single loop bracket.

In an alternative embodiment of the invention, the axial connector is wound around the peaks/valleys and passes through the interstices of the first knot.

In an alternative embodiment of the present invention, the number of the first knots of one of the first circumferential connectors is greater than or equal to half of the number of peaks/valleys of one of the single loop brackets.

In an optional embodiment of the present invention, the first circumferential connector further includes a second knot, where the second knot is a knot formed by winding the first circumferential connector by itself and located between adjacent peaks or troughs of the single ring bracket, and the axial connector is alternately wound on the peaks, the first knot, the second knot, the troughs, and the first knot.

In an alternative embodiment of the invention, the axial connector is wound in the void of the second knot.

In an alternative embodiment of the present invention, the axial connectors include at least two axial connectors, one of which is in an "N" shape, and the other of which is in an inverted "N" shape.

In an alternative embodiment of the invention, the axial connectors are distributed over a part of the circumference of the vascular stent.

In an alternative embodiment of the invention, the wire of the connector has an axial cross-sectional dimension that is smaller than the axial cross-sectional dimension of the wire of the single loop stent.

In an alternative embodiment of the present invention, a ratio of an axial cross-sectional dimension of the wire of the single ring support to an axial cross-sectional dimension of the wire of the connector is between 2 and 20.

The vascular stent has good bending performance, can obtain different supporting performance and flexibility performance in the circumferential direction according to the requirement, and can be well adapted to the bent vascular environment.

The vascular stent can maintain uniformity of the stent morphology, can obtain different supporting performance and flexibility in the circumferential direction, and can better adapt to vascular anatomy structures.

The local tectorial membrane of the vascular stent and the excellent bending performance of the stent are matched, so that the vascular stent can be used for DebakeyII type interventional treatment without branch vessel reconstruction and uninvolved aortic arch interlayer.

The vascular stent has better fatigue resistance and can not damage the inner wall of the blood vessel.

The preparation method of the vascular stent can easily change the overall mechanical properties of the stent and produce more stents with different mechanical properties.

Drawings

Fig. 1 shows a schematic structural view of a vascular stent of the present invention.

Fig. 2 shows a schematic perspective view of a single ring stent of the vascular stent of the present invention.

Fig. 3 shows a front view of a single loop stent of the vascular stent of the present invention.

Fig. 4 is a schematic diagram showing the structure of the single ring stent of the present invention in which the lengths of the individual struts are not equal.

Figures 5a-5c show schematic views of three alternative forms of peaks or troughs of a vascular stent of the present invention.

Fig. 6 shows a schematic representation of the relative positions of a single loop stent of a vascular stent of the present invention.

Fig. 7 is a schematic perspective view showing a connector of a stent of the present invention.

Figure 8 shows a front view of the connector of the vascular stent of the present invention.

Fig. 9 shows a schematic winding of the connector of the vascular stent of the present invention.

Fig. 10a-10e show five alternative schematics of the lattice morphology of the connectors of the vascular stent of the present invention.

Fig. 11 shows a schematic structural view of a stent graft of the present invention.

Figures 12a and 12b show a comparative schematic view of a prior art partial stent and a vascular stent of the present invention, respectively, in a more curved configuration.

Figures 13a and 13b show a comparative form of a prior art partial stent and a vascular stent of the present invention after stress on the free side, respectively.

Fig. 14 shows a schematic view of a stent of the present invention for use in a therapeutic DeBakeyII-type sandwich.

Fig. 15 shows a partial enlarged view of the square frame area in fig. 14.

Figures 16a-16c show a comparative schematic of the morphology of a prior art partial stent and a vascular stent of the present invention, respectively, after implantation in a blood vessel.

Description of the reference numerals

The vascular stent 100, without the covered segment 100a, has a covered segment 100b, a single-ring stent 10, 10', a peak 101, a wave rod 102, a wave trough 103, a tube sleeve 104, connectors 20, 20',21 circumferential connectors, a first circumferential connector 211, a first knot 2111, a second knot 2112, a second circumferential connector 212, an axial connector 22, a first axial connector 22a, a second axial connector 22b, a covered membrane 30, a sheath tube 40, a fixed jaw 50, an inner heart tube 60, an ascending aorta 701, an aortic arch 702, a descending aorta 703, a branch vessel 704, a sandwich 705.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

Please refer to fig. 1-16. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.

For convenience of description, the terminology appearing herein is explained:

The small curve is that the blood vessel, the bracket and the like are similar to a circular tube shape, and when the blood vessel, the bracket and the like are bent, the side with smaller bending radius is the small curve side.

The large curve is similar to a circular tube shape, such as a blood vessel, a bracket and the like, and when the blood vessel, the bracket and the like are bent, the side with larger bending radius is the large curve side.

The near-heart end is that arterial blood vessels emitted from the heart gradually branch into capillaries and then gradually collect into venous blood vessels to return to the heart, wherein any section of blood vessels is called as the near-heart end at the end near the centrifugal heart.

Distal end, i.e. the arterial blood vessel from the heart gradually branches into capillaries, and gradually merges into venous blood vessel to return to the heart, wherein any section of blood vessel is called distal end at the end far away from the heart.

The axial direction is that the blood vessel, the intervention stent and the like are in a similar circular tube shape, and if the blood vessel, the intervention stent and the like are regarded as a cylinder, the cylinder rotation axis is defined as the axial direction.

The radial direction is perpendicular to the axial direction, namely the radial direction or the diameter direction of the end face circle of the cylinder, and the radial direction is perpendicular to the axial space.

The circumferential direction is the circumferential direction, and the circumferential direction and the axial direction and the radial direction form three orthogonal directions of the cylindrical coordinates together.

The present invention introduces an interventional stent 100 (also referred to as a stent), wherein fig. 1 shows a schematic structural diagram of the stent 100 according to the present invention. As shown in fig. 1, the vascular stent is an entire prosthesis for interventional therapy, and the vascular stent 100 is an assembly body formed by combining three components of a single-ring stent 10, a connecting body 20, a covering film 30 and the like through a certain process.

It should be noted that, in some embodiments, the vascular stent 100 may not include the covering film 30, but may be an assembly directly formed by combining the single-ring stent 10 and the connector 20 through a certain process. The vascular stent 100 will be described below by taking the example in which it includes the single-ring stent 10, the connector 20, and the cover 30.

As shown in fig. 1, in the present invention, the stent 100 is composed of a multi-ring single-ring stent 10 and a multi-ring connector 20, the stent is a tubular network structure, and the covering film 30 is a layer of flexible film material attached to the single-ring stent 10 or the connector 20. The multiple rings of annular single-ring stents 10 are sequentially arranged at intervals in parallel from the proximal end to the distal end of the vascular stent 100, and one ring of connectors 20 is arranged between every two adjacent rings of single-ring stents 10, namely the single-ring stents 10 and the connectors 20 are distributed at intervals along the axial direction of the vascular stent 100. It should be noted that, in some embodiments, the connector 20 may not be disposed between two adjacent single ring brackets 10 connected by the cover film 30. The single ring stent 10 has stronger bending resistance and supporting property than the connector, and when the stent 100 is implanted into a lesion site, the stent 100 can be anchored and supported at the lesion site by means of a plurality of single ring stents 10 to prevent the stent 100 from being displaced. The connector 20 has a stronger bending property and flexibility than the single-ring stent 10, and can be bent by means of a plurality of connectors 20 when the stent 100 is delivered in a bent blood vessel and placed in the bent blood vessel. The covering film 30 has high sealing performance, and when the vascular stent 100 is implanted into a lesion, the covering film 30 can cover the lesion and seal the lesion, so that blood in the aorta is prevented from entering the intima of the blood vessel from the breach of the intima of the blood vessel, and the intima and the media of the blood vessel are prevented from being separated continuously, thereby alleviating the symptoms.

Fig. 2 shows a schematic perspective view of the single ring bracket 10 of the present invention, and fig. 3 shows a front view of the single ring bracket 10 of the present invention. Referring to fig. 2 and 3, in the present invention, a single ring stent 10 is one of the components constituting a stent 100, and the stent 100 comprises a plurality of single ring stents 10. Each of the single ring stents 10 extends in the circumferential direction of the stent 100 to form a closed loop shape, and undulates in the axial direction of the stent 100 while extending in the circumferential direction, that is, the single ring stent 10 is wavy in its axial direction.

In the present invention, the single ring support 10 is a ring which is formed by bending and heat-treating a metal wire with a circular cross section and is circular or nearly circular as a whole, and the single ring support 10 undulates in the axial direction while extending in the circumferential direction. The single ring stent 10 is made of a shape memory alloy, such as nickel titanium alloy (NiTi). The overall height H1 of the single ring stent 10 is in the range of 5 to 20mm, such as 5mm, 10mm, 15mm or 20mm, the overall diameter D1 of the single ring stent 10 is in the range of 10 to 50mm, such as 10mm, 20mm, 30mm, 40mm or 50mm, and the cross-sectional diameter D1 of the wire of the single ring stent 10 is in the range of 0.1 to 1mm, such as 0.1mm, 0.2mm, 0.4mm, 0.6mm, 0.8mm or 1mm.

In an alternative embodiment, the wire cross-section of the single loop stent 10 may be square, trapezoidal, or any other suitable shape, and when the wire cross-section of the single loop stent 10 is square, the diagonal dimension of the square is defined as d1, which may range from 0.1mm to 1mm, such as 0.1mm, 0.2mm, 0.4mm, 0.6mm, 0.8mm, or 1mm.

In an alternative embodiment, the single ring stent 10 may also be made by laser cutting a metal tube, and then expanding and shaping the tube by heat treatment. In an alternative embodiment, the single loop stent 10 may also be manufactured in one step from 3D metal printing.

Referring to fig. 2 and 3, in the present invention, the single ring stent 10 includes a peak 101, a trough 103 and a wave rod 102 connecting the peak 101 and the trough 103, wherein one peak 101 and two wave rods 102 adjacent thereto form a wave, the peak 101 and the trough 103 are relatively speaking, the single ring stent 10 is inverted in the axial direction, the peak becomes the trough, and the trough becomes the crest. The wavenumber of one single ring stent 10 is not fixed, and the setting according to the physiological anatomy structure of the aorta is carried out according to the values of the overall height H1 of the single ring stent 10 and the overall diameter D1 of the single ring stent 10. As an example, the wave number of one single ring scaffold 10 is between 3 and 12, wherein the case where the wave number of the single ring scaffold 10 is 6 is shown in fig. 2.

In the present invention, the radius R of the excess fillet between the peaks 101 or troughs 103 is in the range of 0-5mm, such as 0mm (corresponding to the case where two adjacent waverods 102 are directly connected, without filleting), 1mm, 2mm, 3mm, 4mm or 5mm. The R values of a single ring stent 10 are not necessarily the same, i.e., the peaks 101 or troughs 103 of the same single ring stent 10 may be the same or different in size. The magnitude of each R value should be set according to the requirements of the function such as the later press-holding of the stent 100. As an example, fig. 3 shows a situation in which several peaks 101 or valleys 103 of the same single loop stent 10 are the same size.

In the present invention, the opening angle of the wave crest 101 (i.e. the included angle α between two adjacent wave rods 102) ranges from 10 ° to 70 °, such as 10 °, 20 °, 30 °, 40 °, 50 °, 60 ° or 70 °, and the opening angles α of several wave crests 101 in the same single-ring stent 10 may be the same or different, and the values of α should be set according to the requirement of the later pressing and holding functions of the vascular stent 100.

Fig. 2 and 3 show that all the wavebars 102 of the single-ring stent 10 are cut from the adjacent peaks 101 or troughs 103, and all the alpha values are at the same acute angle (of course, an obtuse angle is also possible). It will be appreciated that the wave beam 102 and the wave crest 101 or the wave trough 103 may also take one of the wave forms shown in fig. 5a-5c, wherein in fig. 5a the wave beam 102 is not tangential to the wave crest 101 or the wave trough 103 and α is an acute angle, the wave crest 101 or the wave trough 103 takes on a major arc form, in fig. 5b the wave beam 102 is not tangential to the wave crest 101 or the wave trough 103 and α is an obtuse angle, the wave crest 101 or the wave trough 103 takes on a minor arc form, in fig. 5c the wave crest 101 or the wave trough 103 may take on an "M" shape or a "W" shape, etc.

Referring to fig. 2-4, in the present invention, the wave beam 102 is a straight beam connecting between the wave crest 101 and the wave trough 103. The length L1 of the wave rod 102 ranges from 1 to 30mm, and the length L1 of the wave rod 102 ranges from 1 to 30mm, such as 1mm, 5mm, 10mm, 15mm, 20mm, 25mm, or 30mm. In the same single-ring stent 10, the lengths L1 of the plurality of waverods 102 may be the same or different. As an example, a case where the lengths L1 of all the waverods 102 of each single ring bracket 10 are equal is shown in fig. 3. As an example, fig. 4 shows a schematic structural diagram of a single-ring stent 10 with various waverods 102 having different lengths, and when the lengths L1 of the waverods 102 are different, the waves in the single-ring stent 10 have different sizes, and the bending performance of the waves with different sizes is different, so that the single-ring stent can better adapt to the bent blood vessel. The wave beam 102 may be in the form of an "S" beam, a "Z" beam, or the like, in addition to the straight beam.

Referring to fig. 2, in the present invention, the single ring stent 10 further comprises a tube sleeve 104, and the tube sleeve 104 may be a thin-walled metal sleeve with an inner diameter slightly larger than the cross-sectional diameter d1 of the wire of the single ring stent 10. Fig. 2 shows a single loop stent 10 comprising 2 sleeves 104, one sleeve 104 acting to join the ends of the wires making up the single loop stent 10, by clamping or welding, one wire into an end-to-end loop. Another sleeve 104 is threaded over the wave rod 102, burying the wire ends of the connector 20 in the sleeve 104, and clamping the sleeve 104, so that the sleeve 104 and the wire ends are fixed to the wave rod 102. The sleeve 104 is made of stainless steel, niTi, or other suitable metal. It will be appreciated that only one sleeve 104 may be used to connect the wires of the single loop stent 10 end to end, and the ends of the connector 20 trimmed without being embedded in the sleeve 104.

It will be appreciated that when the single loop stent 10 is manufactured for cutting or metal printing, the use of the sleeve 104 is not required.

As shown in fig. 6, the relative positions of the plurality of single ring stents 10 in the vascular stent 100 may be the same or different. In fig. 6, in the lower elliptical area, the peaks 101 of two adjacent single-ring brackets 10 are arranged in a staggered manner, the peak 101 of one single-ring bracket 10 is located between two peaks 101 of the other single-ring bracket 10, for example, two adjacent single-ring brackets 10, the peak 101 of one single-ring bracket 10 may be vertically opposite to the valley 103 of the other single-ring bracket 10 in the axial direction, in fig. 6, in the upper elliptical area, two adjacent single-ring brackets 10, the peak 101 of one single-ring bracket 10 may be obliquely opposite to the valley 103 of the other single-ring bracket 10 in the axial direction, that is, the peak 101 of one single-ring bracket 10 is located between two valleys 103 of the other single-ring bracket 10, for example, the peaks 101 of two adjacent single-ring brackets 10 are aligned.

Fig. 7 shows a perspective view of the connector 20 of the present invention, fig. 8 shows a front plan view of the connector 20 of the present invention, and fig. 9 shows a winding view of the connector of the vascular stent of the present invention.

Referring to fig. 7 to 9, in the present invention, the connector 20 is composed of a plurality of rope-like flexible bodies wound around a plurality of single ring brackets 10 to connect adjacent single ring brackets 10. At the same time, a plurality of rope flexible bodies are also interwoven to form a connecting body 20 together. The flexible body of the rope type is, for example, a metal wire, and the material of the connecting body 20 is a shape memory alloy, such as nickel titanium alloy (NiTi). The wire used in the connector 20 has an axial cross-sectional dimension d2 that is less than the axial cross-sectional dimension d1, d1:d2=2-20, such as 2, 5,8, 11, 14, 17, 20, of the wire used in the single loop stent 10. The connecting body 20 comprises a circumferential connecting body 21 and an axial connecting body 22.

Referring to fig. 7-9, in the present invention, the circumferential connector 21 includes a first circumferential connector 211 and a second circumferential connector 212. The first circumferential connector 211 is a metal wire which is wound around and connected to the trough 103 or the crest 101 of the single ring bracket 10 in the circumferential direction, and is shaped by bending, winding, and heat treatment of the metal wire, and has the same shape in the circumferential direction as the single ring bracket 10, and is a circular or nearly circular ring. The first circumferential connector 211 may be a single stranded wire or a multi-stranded twisted wire. The first circumferential connector 21 includes a first knot 2111 formed by winding around the peaks 101 or the valleys 103 and a second knot 2112 wound around itself and located between adjacent peaks 101 or valleys 103. The first knot 2111 may be any suitable knot form such as a Prussian knot, a single knot, a splayed knot, a hook-up knot, or a direct loop, and the second knot 2112 may be any suitable knot form such as a Prussian knot, a single knot, a splayed knot, a hook-up knot, or a direct loop.

The number of first knots 2111 on each first circumferential connector 21 is not limited, nor is it limited to being uniformly circumferentially distributed, i.e., a portion of the peaks 101 or valleys 103 may not be tied with first knots 2111. First knots 2111 are at most as many as peaks 101 or valleys 103, but at least not preferably less than half the number of peaks 101 or valleys 103 per first circumferential connector 21.

The number of second knots 2112 on one first circumferential connector 21 is not limited, i.e. there may be no knots wound around itself between adjacent peaks 101 or troughs 103, and there may be a plurality of knots. The number of second knots 2112 should match the shape of axial connector 22.

Axial connector 22 is threaded around peaks 101 and first knots 2111, second knots 2112, valleys 103 and first knots 2111. The axial connector 22 is formed by bending, winding and heat treatment shaping of metal wires, and the shape of the axial connector 22 in the circumferential direction is a circular or approximately circular ring or a semicircular or approximately semicircular arc which is matched with the single-ring bracket 10. When the axial connector 22 is wound around the peak 101 or the trough 103, it is necessary to pass through the gap of the first knot 2111, so as to ensure that the axial connector 22 binds itself, the first knot 2111 and the peak 101 or the trough 103 together, so as to limit the sliding of the winding points of the first knot 2111 and the axial connector 22 on the single ring bracket 10. The axial connector 22 needs to be wrapped around the void of the second knot 2112 to limit the sliding of the axial connector 22 over the first circumferential connector 211.

As shown in fig. 1 and 7, in the present invention, the axial connectors 22 are arranged in a non-uniform arrangement in the circumferential direction, and the axial connectors 22 are provided in a partial region in the axial direction, and the axial connectors 22 are not provided in other regions, in other words, the adjacent single ring brackets 10 may be axially connected only in a partial region, and the other regions are not axially connected, and the portions of the single ring brackets not axially connected are in a free state in the axial direction.

It will be appreciated that, in other embodiments, the axial connectors 22 are unevenly distributed in the circumferential direction, which may also mean that the axial connectors 22 are inconsistent in the circumferential density, and the partial areas are densely distributed and the partial areas are sparsely distributed. It should be noted that, in the present invention, when the wave crest 101 or the wave trough 103 is in the form shown in fig. 5a-5c, the sliding of the first knot 2111 on the single loop bracket 10 can be better resisted.

In the present invention, the axial connector 22 may be in the form of a knot such as a Prussian knot, a single knot, a splayed knot, or a hook knot, in addition to the direct winding manner shown in fig. 9, at the first knot 2111 or the second knot 2112. For example, when the first knot 2111 is a Prussian knot, the axial connector 22 may be a reverse Prussian knot again to form an interpenetrating double Prussian knot. When second knot 2112 is a single knot, axial connector 22 may be a single knot again here, forming a double knot.

In the present invention, the number and uniformity of winding points of the axial connector 22 on the peaks 101, the valleys 103 or the circumferential connector 21 are not fixed, that is, winding may not be performed on a part of the peaks 101, the valleys 103 or a certain section of the circumferential connector 21.

As shown in fig. 9, the connecting body 20 includes two axial connecting bodies 22a and 22b, one axial connecting body 22b is of an N-type with staggered height, and the other axial connecting body 22a is of an inverted N-type with staggered height.

Fig. 9 shows a case where the first knot 2111 is a prussian knot and the second knot 2112 is a single knot, the first knot 2111 is provided on each peak 101 or trough 103, one second knot 2112 is provided between each adjacent peak 101 or trough 103, and the axial connector 22 is wound once on each of the first knot 2111 and the second knot 2112.

As shown in fig. 9, in the present invention, the second circumferential connecting body 212 is located between two adjacent first circumferential connecting bodies 211 and can be connected to the axial connecting body 22 by winding in the circumferential direction. When the axial connecting body 22 is provided on a circumferential partial region, the second circumferential connecting body 212 is also arranged only in the region corresponding to the axial connecting body 22.

In fig. 9, the connector 20 includes three circumferential connectors 21, two first circumferential connectors 211 and one second circumferential connector 212, respectively, one first circumferential connector 211 is wound on the peak 101 of the single-ring bracket 10 on one side, the other first circumferential connector 211 is wound on the trough 103 of the single-ring bracket 10 on the other side, and one second circumferential connector 212 is located on the middle plane of the axial connector 22 in the axial direction, is wound on the axial connector 22, and optionally can be tied on the axial connector 22 in a suitable tying manner.

In the present invention, the number and form of the axial connectors 22 between two adjacent single ring brackets 10 are not limited to those shown in fig. 9. The number and configuration of the axial connectors 22 should be matched as desired for the desired support and compliance of the stent 100. As an example, the number of circumferential connectors 21 between two adjacent single ring brackets 10 is 2-5, that is, in addition to the first circumferential connectors 211 wound around the opposite peaks 101 and troughs 103 of two adjacent single ring brackets 10, 0-3 second circumferential connectors 212 are distributed in the axial direction of the axial connectors 22, that is, in some embodiments, the connectors may not be provided with the second circumferential connectors 212. The number of the axial connectors 22 between two adjacent single ring brackets 10 can be 1-3, and the shape is an N type, an inverse N type or a Z type.

As shown in fig. 9, the connector 20 is in the form of a mesh formed of several triangles of different orientations. It will be appreciated that depending on the arrangement of the circumferential and axial connectors 21, 22 described above, the final mesh configuration of the connector 20 may also be a variety of mesh configurations as shown in fig. 10 a-10 e. The mesh form of the same connector 20 may be single or may be different in sections. The grid pattern of the connectors 20 on the same stent 100 may be the same or different.

According to the structural design of the connector 20, the circumferential connector 21 and the axial connector 22 form mutual limit, so that the sliding of the nodes on the wave rods of the bracket is prevented.

The conventional connector of the bare stent can only take the top point of the stent ring of the single-ring stent as the winding position of the node, while the circumferential connector 21 can be used as the winding point of the axial connector everywhere in the circumferential direction of 360 degrees, and the axial connector 22 has more node winding positions, so that the axial connector 22 can be arranged on one side of the vascular stent in a concentrated way and is free on the other side of the vascular stent in the axial direction.

As shown in fig. 1, in the present invention, the cover 30 is one of the components constituting the stent 100, and the stent 100 may include several covers 30. The cover 30 is a layer of flexible film material that is attached to the single loop stent 10 or the connector 20. The material of the coating film 30 may be, for example, PET (polyester fiber, dacron) or EPTFE (polytetrafluoroethylene). The coating 30 is attached to at least one single ring stent 10 or one connector 20, and at most to all single ring stents 10 and connectors 20.

As shown in fig. 11, the placement of the cover 30 is optional and may be attached to different single loop stents 10 or connectors 20 of the stent 100 as desired. The cover 30 may be attached to the outside, inside or both the inside and outside of the single ring stent 10 or the connector 20. The cover 30 may be attached to the single loop stent 10 or the connector 20 by any suitable means, such as adhesive (e.g., hot melt), sewing, etc.

The beneficial effects of the vascular stent 100 of the present invention will be explained below by comparison with existing stents.

1. The vascular stent 100 of the invention has good bending performance, can obtain different supporting performance and flexibility performance in the circumferential direction according to the requirement, and can be well adapted to the bent vascular environment.

As shown in fig. 12a, in the existing partial bare stent, the crest and trough of two adjacent single ring stents are connected by silk threads, so that the bending performance is poor, the supporting performance and the flexibility of the whole stent in the circumferential direction are uniform, and the whole stent cannot be well adapted to the bent vascular environment. When the support is bent greatly, the wave rods of the adjacent single-ring supports at the large bending positions of the support are excessively pulled by the silk threads, and the support is excessively bent towards the central axis at the small bending positions, so that the bending section is distorted.

As shown in fig. 12b, the vascular stent 100 of the present invention has good bending performance, and the connector 20 can be designed in sections according to the requirement to obtain different supporting performance and flexibility in the circumferential direction, so as to better adapt to the bending vascular environment. The part without the axial connector 22 can be used as the side of the large bend of the bracket, so that the bracket part at the large bend is in a free state in the axial direction, and the parts of the bracket at the small bend only overlap each other at the moment, so that the bracket cannot be excessively bent towards the central axis.

2. The vascular stent 100 of the invention can not only maintain the uniformity of the stent morphology, but also obtain different supporting performance and flexibility in the circumferential direction, and the whole stent can better adapt to vascular anatomy structures.

As shown in fig. 13a, in the existing partial stent, since there is no circumferential connector as a winding point of the axial connector, the axial connector can only use the peak and trough of each ring stent as a connection point, and in order to ensure the circumferential uniformity of the whole stent, the axial connectors must also be uniformly distributed circumferentially on the single ring stent, which also results in uniform support and compliance of the whole stent in the circumferential direction. If the axial connector is withdrawn, the free wave of the single ring bracket may be deformed axially by external force. For example, when the interventional operation is performed, the whole stent may not be properly placed, and the position may be adjusted, and if the stent is moved at this time, free waves may scratch the inner wall of the blood vessel, and the blood vessel may be deformed axially, thereby damaging the blood vessel.

As shown in fig. 13b, since the circumferential connector 21 is used as a winding point of the axial connector 22, the axial connector 22 can be freely arranged in the circumferential direction according to design requirements, so as to obtain different circumferential supporting performance and flexibility. Meanwhile, due to the limitation of the circumferential connector 21, the single-ring bracket 10 has no absolute free wave and cannot generate axial deformation. When the vascular stent 100 of the present invention is placed in the ascending aorta, the proximal end of the ascending aorta will contract more than the distal end along with the beating of the heart, so that the proximal end supporting performance of the vascular stent 100 can be reduced by the design and adjustment of the circumferential connector 21 and the axial connector 22 of the present invention, without changing the mechanical properties of the rest of the vascular stent 100, so as to better adapt to the contraction and relaxation of the proximal end of the ascending aorta.

3. As shown in fig. 14 and 15, the local coating of the stent of the present invention and the excellent bending performance of the stent are matched, so that the stent 100 of the present invention can be used for DebakeyII type interventional treatment without branch vessel reconstruction and without involvement of aortic arch in the dissection.

The current stage is dedicated to the treatment of the DebakeyII type of stent, particularly for the DebakeyII type, where no branch vessel 704 reconstruction is required and the dissection 705 does not involve the aortic arch 702. Because the ascending aorta 701 is short and close to the heart, to prevent the stent from coming off of the vessel that is intervening in this region, it is desirable that the stent has a length sufficient to span the aortic arch 702 to complete the anchoring. If the traditional stent is used for interventional therapy, the polymer film can block the blood supply of the branch vessel 704 at the aortic arch 702, so that the film 30 needs to be perforated, and the precise adaptation of the perforation and the branch vessel 704 is completed, which greatly increases the operation difficulty.

As shown in fig. 14 and 15, a covering film 30 is attached to the proximal end of the vascular stent 100 of the present invention, and this segment can close the cleavage of the dissection 705 in the ascending aorta 701, so as to achieve the purpose of treating the DebakeyII dissection. The stent 100 of the present invention spans the non-covered segment 100a of the aortic arch 702 not only permits free blood flow from the thoracic aortic vessel to the branch vessel 704, but also prevents the dissection 705 from opening to the aortic arch 702. Meanwhile, the vascular stent 100 of the invention can design the proper size of the single-ring stent 10 and the size of the connector 20 according to the interval of the branch vessels 704 of the aortic arch 702, so that the adjacent single-ring stent 10 is clamped at two sides of the bifurcation of the branch vessels 704, and the bifurcation of the branch vessels 704 is ensured to be completely free from interference of the single-ring stent 10 or the connector 20, thereby greatly ensuring the smoothness of blood circulation.

The vascular stent 100 of the present invention can also be precisely positioned, if the blood vessel area covered by the axial connector 22 grows with a small branch blood vessel 704, the axial connector 22 can be densely arranged at a part far away from the bifurcation of the branch blood vessel 704, and the axial connector is sparsely arranged at the bifurcation of the branch blood vessel 704, so as to reduce the blood flow interference to the branch blood vessel and ensure the smoothness of blood circulation.

In addition, the attached coating 30 at the distal end of the stent 100 can serve to relieve the free apices at the stent ends from pressing against the inner wall of the vessel and reduce the risk of rupture of the intima.

4. The stent 100 of the present invention has better fatigue resistance without damaging the inner wall of the vessel.

The prior art stent shown in fig. 16a, because there is no circumferential connector as a winding point of the axial connector, the axial connectors are uniformly distributed circumferentially on the single ring stent, which also results in uniform support and compliance of the overall stent in the circumferential direction. When the integral stent is placed in a curved vessel, the integral stent on the inner side is in a compressed state and the integral stent on the outer side is in a stretched state. Because the outer axial connector transits and pulls the outer side of the single-ring bracket, the outer side wave of the single-ring bracket is pulled to generate deformation such as inner buckles (see the area shown by the circle in fig. 16 a). According to the basic knowledge of the material mechanics, the fatigue performance of the single ring bracket and the connector in the state is weakened. In the invention, the connector adopts the connectors with different designs in sections, so that the problems can be better solved. The axial connector is arranged at the part without transition traction on the inner side so as to connect a plurality of single ring stents to ensure the continuity of the whole stent, and the design of the axial connector is canceled at the part with transition traction on the outer side so as to ensure the flexibility of the outer side of the whole stent, thereby leading the vascular stent 100 to have better fatigue resistance.

The conventional stent shown in fig. 16b has no circumferential connector as a winding point of the axial connector and the axial connector on the outer side is removed, when the integral stent is placed in a curved blood vessel, the integral stent on the inner side is in a compressed state, the outer wave of the single-ring stent is completely in a free state, the outer wave of the single-ring stent can generate an outward warping state (see the area shown by the circle in fig. 16 b), and at this time, the outward warping outer wave can damage the inner wall of the blood vessel, especially the inner cortex of the blood vessel in a pathological state is very easily scratched.

As shown in fig. 16c, the vascular stent 100 of the present patent is provided with the axial connector 22 in the inner region and the axial connector 22 is not provided in the outer region, i.e., the external waves of the single-ring stent 10 are not subject to the transitional pulling of the connector 20. Due to the limitation of the circumferential connector 21, the external waves are not completely dissociated to generate external warping, so that the fatigue performance of the whole stent is not affected, and the inner wall of the blood vessel is not damaged.

In the description herein, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, components, methods, components, materials, parts, and so forth. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

It will also be appreciated that one or more of the elements shown in the figures may also be implemented in a more separated or integrated manner, or even removed because of inoperability in certain circumstances or provided because it may be useful depending on the particular application.

In addition, any labeled arrows in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically indicated. Furthermore, the term "or" as used herein is generally intended to mean "and/or" unless specified otherwise. Combinations of parts or steps will also be considered as being noted where terminology is foreseen as rendering the ability to separate or combine is unclear.

The above description of illustrated embodiments of the invention, including what is described in the abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. Although specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As noted, these modifications can be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.

The systems and methods have been described herein in general terms as being helpful in understanding the details of the present invention. Furthermore, various specific details have been set forth in order to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, and/or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

Thus, although the invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of the invention will be employed without a corresponding use of other features without departing from the scope and spirit of the invention as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the invention not be limited to the particular terms used in following claims and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Accordingly, the scope of the invention should be determined only by the following claims.

Claims (14)

1. A vascular stent, comprising:

the single-ring brackets are axially arranged at intervals and undulate along the axial direction while extending along the circumferential direction;

the two adjacent single-ring brackets are connected through the connectors;

the connecting body comprises two annular first circumferential connecting bodies and at least one axial connecting body;

One first circumferential connector sequentially winds the wave crest of one of the two adjacent single-ring brackets in the circumferential direction, the other first circumferential connector sequentially winds the wave trough of the other of the two adjacent single-ring brackets in the circumferential direction, and the first circumferential connector comprises a first rope knot formed by winding on the wave crest or the wave trough and a second rope knot which is wound on the first rope knot and positioned between the adjacent wave crest or the wave trough;

The axial connector is located between two adjacent first circumference connectors, the axial connector is alternately wound on the crest, the first knot, the second knot, the trough and the first knot while extending in the circumferential direction, so as to limit the sliding of the winding points of the first knot and the axial connector on the single ring support and limit the sliding of the axial connector on the first circumference connector, and the axial connector is unevenly distributed in the circumferential direction.

2. The vascular stent of claim 1, wherein the material of the single ring stent is a shape memory alloy.

3. The vascular stent of claim 1, wherein the single loop stent comprises peaks, troughs, and struts connecting the peaks and the troughs, the struts being tangential or non-tangential to the peaks/troughs.

4. The vascular stent of claim 1, wherein the relative positions of the single ring stents of the vascular stent are the same or different.

5. The vascular stent of claim 1, wherein the material of the plurality of connectors is a shape memory alloy.

6. The vascular stent of claim 1, wherein the plurality of connectors are in a lattice configuration.

7. The vascular stent of claim 1, further comprising a cover attached to the single ring stent or the plurality of connectors.

8. The vascular stent of claim 1, further comprising a second circumferential connector positioned between two adjacent first circumferential connectors and circumferentially wrapped around the axial connector.

9. The vascular stent of claim 8, wherein the first circumferential connector is a single wire or a plurality of twisted wires and the second circumferential connector is a single wire or a plurality of twisted wires.

10. The vascular stent of claim 1, wherein the number of first knots of one of the first circumferential connectors is greater than or equal to half the number of peaks/valleys of one of the single loop stents.

11. The vascular stent of claim 1, wherein the axial connectors include at least two, one of the axial connectors being of an "N" type and the other of the axial connectors being of a reverse "N" type.

12. The vascular stent of claim 1, wherein the axial connectors are distributed over a portion of the circumference of the vascular stent.

13. The vascular stent of claim 1, wherein the wire of the plurality of connectors has an axial cross-sectional dimension that is smaller than an axial cross-sectional dimension of the wire of the single ring stent.

14. The vascular stent of claim 13, wherein the ratio of the axial cross-sectional dimension of the wire of the single loop stent to the axial cross-sectional dimension of the wire of the plurality of connectors is between 2 and 20.