CN113413256A

CN113413256A - Self-expanding stent

Info

Publication number: CN113413256A
Application number: CN202110777379.7A
Authority: CN
Inventors: 汪泽辉; 陈奕龙
Original assignee: Shenzhen Kyd Biomedical Technology Co ltd
Current assignee: Shenzhen Kyd Biomedical Technology Co ltd; Shenzhen Xinlitai Medical Equipment Co ltd
Priority date: 2019-01-31
Filing date: 2019-01-31
Publication date: 2021-09-21
Anticipated expiration: 2039-01-31
Also published as: CN109662819B; CN113413256B; CN109662819A

Abstract

The invention relates to the technical field of medical instruments for interventional operation, and particularly discloses a self-expanding stent suitable for supporting a narrow lumen, and a preparation method and application thereof. The invention can solve the technical problem that the performance of the stent in the prior art can not completely meet the requirement of iliac vein implantation, has higher safety and is particularly suitable for treating iliac vein stenosis.

Description

Self-expanding stent

The application is filed as original application No. 2019100963223, namely divisional application entitled "a self-expanding stent and a preparation method and application thereof", wherein the application date of the original application is 2019, 01 and 31.

Technical Field

The invention relates to the technical field of medical instruments for interventional operation, in particular to a self-expanding stent suitable for supporting a narrow lumen and a preparation method and application thereof.

Background

The stent is used for being placed in a lesion section of a lumen so as to support the lumen of a narrow occlusion section and keep the lumen smooth. Typically, the stent is used for being placed in a diseased section of a blood vessel so as to support the blood vessel at a stenotic occlusion section, reduce the elastic retraction and the reshaping of the blood vessel and keep the blood flow of a lumen unobstructed. Due to differences in the physiological structure of blood vessels at different parts of the human body, special stents have been developed which are suitable for different diseased sections of blood vessels, and stents of different indications cannot be used instead in normal cases. At present, a plurality of blood vessel supporting stents are researched and applied, such as coronary stents, peripheral arterial stents and the like, and a plurality of mature products are already on the market.

The most common clinical venous stenosis is iliac vein stenosis, and the causes include Cockett Syndrome, Postthrombotic Syndrome (PTS), and tumor compression. The most important of them is the Cockett syndrome, also called iliac vein compression syndrome, which means that the left iliac general vein is pressed for a long time by the right iliac artery crossed from the front and the mechanical action generated by the pulsation thereof and the pressing of the fifth lumbar vertebra from the back when the left iliac general vein is converged into the inferior vena cava, so that the intimal hyperplasia of the left iliac general vein forms acanthosis, the intracavity adhesion, the lumen stenosis or occlusion and the like, and further the iliac vein reflux is blocked, thus leading to the consequences of lower limb deep vein thrombosis, varicosity, pigmentation, lower limb erosion and the like.

The stent is implanted in the lesion section of the left common iliac vein through an interventional operation, which is the first choice for treating the Cockett syndrome. However, no mature product is available on the market at present for the blood vessel stent suitable for the iliac veins, especially the left common iliac vein, and other types of stents are adopted for clinical use instead. Typically, such as the Wallstent manufactured by boston scientific and the more commonly used E-luminaexx peripheral arterial stent manufactured by barde, none of the above stents have been developed for the physiological anatomy of the iliac vein, and the application to the iliac vein is still insufficient and may have potential risks.

The ideal iliac vein stent has the particularity that:

1. compared with the common vein or artery vascular stenosis which is the deposition of embolus on the inner wall of a blood vessel or the hyperplasia of intima of the blood vessel, the stenosis lesion section of the left common iliac vein of the Cockett syndrome occurs, mainly because the artery and the fifth lumbar vertebra are physically pressed and the fiber adhesion in the blood vessel is caused by the physical compression, the stent is required to have stronger supporting performance;

2. the iliac vein is tightly attached to the pelvis to walk, the physiological structure is more bent, and the support is required to have excellent flexibility;

3. the stenosis section of the left common iliac vein is usually close to an opening of the left common iliac vein which is converged into the inferior vena cava, and in order to avoid that the stent cannot completely cover the stenosis section of the blood vessel due to the fact that the stent is shortened or drifted after the stent is released, the two ends of the stent are required to exceed the lesion sections when the stent is released into the blood vessel, so that the far end of the stent extends into the inferior vena cava, and the far end of the stent can interfere with the blood flow at the opposite side;

4. the opening of the left common iliac vein which is converged into the inferior vena cava is in a horn mouth shape, the distal end of the bracket is difficult to position at the opening, and the bracket is easy to jump forwards when released, so that the bracket is released and positioned inaccurately.

The braided stent represented by a Wallstent stent is a net-shaped stent braided by alloy wires, the alloy wires are staggered to form closed rhombic meshes, and the staggered alloy wires at the meshes are not physically connected, so that the stent has very excellent flexibility and vascular adaptability, but the stent has weak supporting performance, inaccurate positioning and short shrinkage, and the left common iliac vein needs to be stretched into the inferior vena cava excessively during the clinical operation.

The E-luminaexx stent is a hollowed-out stent formed by cutting a metal tube, the periphery of the stent consists of a plurality of groups of annular wave-shaped rods which are axially arranged in parallel and connecting rods for connecting adjacent wave-shaped rods, and staggered rods for enclosing hollowed-out holes are integrally connected, so that the stent has more excellent supporting performance, but has insufficient anti-fracture capability and insufficient adaptability to bent blood vessels, the left common iliac vein still needs to stretch into the inferior vena cava during clinical operation, and the part stretching into the inferior vena cava inclines towards the inner wall of the inferior vena cava blood vessel to realize the positioning of the stent at the opening of the left common iliac vein.

A stent having a helical pattern, which is formed by cutting a metal tube differently from the aforementioned two types of stents, has been proposed, which has excellent torsional flexibility. For example, chinese patent publications CN108670511A, CN108371572A, CN103784222A, CN203662949U, CN103313681A, CN106137479A, US patent publications US20040044401A, US20130338759A, and PCT patent publication WO2012018844A, etc., respectively, disclose various stents having a single helical support structure. Further, chinese laid-open patent CN 108348345A discloses a stent having a double spiral support structure.

The stent disclosed in the aforementioned patent has a supporting structure of a uniform single helix or double helix provided with a wave structure, and enhanced supporting performance can be obtained to some extent by increasing the number of waves. However, it still cannot solve the contradiction between different structures and performance requirements of the stent at different parts of the iliac vein, and cannot overcome the technical problem that the stent needs to be inserted into the inferior vena cava.

Therefore, there is a need for a stent of new structure and performance, particularly a stent suitable for the iliac vein.

Disclosure of Invention

The invention firstly provides a self-expanding stent, which can solve the technical problem that the stent in the prior art can not meet the application requirements of special lumens such as iliac veins and the like.

The technical scheme adopted by the invention is as follows:

a self-expanding stent comprises two different types of spiral sections which form a hollow tubular shape and are arranged along the axial direction of the hollow tubular shape, wherein the first spiral section comprises a single spiral line, and the second spiral section comprises a double spiral line formed by two parallel spiral lines;

the single helix and the double helix encircle tubular the central axis syntropy, extend to form the circumference shape to single helix and double helix merge into single helix in the transition zone between the two adjacent one end of double helix, single helix and double helix are followed respectively in other transition zone at respective other end tubular circumference closure forms the closed ring that does not have the free end.

Wherein the lead angle of the single spiral line is not more than that of the double spiral line; the spiral line is formed by spiral wave-shaped rods, and the wave-shaped rods are of wave-shaped structures distributed along the length direction of the wave-shaped rods.

The wave forms of the previous spiral turn and the next spiral turn of the single spiral are staggered in the circumferential direction of the tubular shape, and the wave forms of the previous spiral turn and the next spiral turn of the double spiral are parallel in the circumferential direction of the tubular shape.

The nearest wave crest and wave trough are connected between the adjacent wire turns of the single spiral wire by a first connecting part, and the two nearest wave crests or two nearest wave troughs are connected between any spiral wire in the double spiral wires and the adjacent spiral wires by a second connecting part;

the first connecting part and the second connecting part are distributed along the circumference of the tubular shape.

Further, the self-expanding stent further comprises a non-helical section, wherein the non-helical section comprises an inclined ring surrounding the central axis of the tubular shape, the inclined ring is formed by annular corrugated rods, and the inclined ring and the closed ring of the single helix in the first helical section are jointly biased to one side of the radial section of the tubular shape;

the wave forms of the inclined rings and the closed rings of the first spiral section are staggered in the circumferential direction of the pipe shape, and the wave crests and the wave troughs which are closest to each other are connected through a first connecting part.

Preferably, the wave shape of the wave-shaped rod is a Z-shaped wave, the wave height of the wave-shaped rod is 1-5 mm, the wave-shaped rod is provided with 10-25 wave crests or 10-25 wave troughs on every 360-degree spiral turn, and the number of the first connecting parts and the number of the second connecting parts distributed along the circumferential direction of the pipe shape every 360 degrees are respectively 3-8;

the width of the rod body of the corrugated rod is larger than the width of the first connecting part and the second connecting part, the width of the rod body of the corrugated rod is 0.1-0.4 mm, the width of the first connecting part is 0.2-0.5 mm, and the width of the second connecting part is 0.1-0.3 mm;

the length of the first connecting part along the axial direction of the bracket is not more than 2 mm;

the length of the second connecting part along the axial direction of the bracket is greater than the wave height of the corrugated rod, and the difference between the length and the wave height is not greater than 2 mm.

In a preferred embodiment, the first connecting part is angled with respect to the axial direction of the stent, and the second connecting part is substantially parallel to the axial direction of the stent.

Optionally, the two wave-shaped rods of the double helix are combined into one wave-shaped rod in the transition area of the other end of the double helix, and then a closed loop without a free end is formed.

In a preferred embodiment, one of the wave shaped rods, which is a combination of two wave shaped rods, has a tendency that the wave height gradually decreases and the width of the rod gradually decreases as a whole in the circumferential direction of the stent in the transition zone.

Optionally, the length of the first helical section is less than the length of the second helical section; the total length of the support is 50-120 mm, the sum of the lengths of the non-spiral section and the first spiral section is 10-60 mm, and the length of the double-spiral section is 30-100 mm.

The self-expanding stent may be either a straight cylindrical shape or a cylindrical shape with a gradually changing diameter, wherein, in an alternative embodiment, the diameter of the self-expanding stent in an unconstrained, freely expanded state is monotonically gradually changed along the axial direction thereof, and the diameter of the first helical section is larger than the diameter of the second helical section as a whole.

In a preferred embodiment, adjacent first connecting parts in a single helical line are arranged in a staggered manner and adjacent second connecting parts in a double helical line are arranged in parallel along the axial direction of the stent.

Optionally, the first connecting part and the second connecting part are linear or arc-shaped or S-shaped or dumbbell-shaped.

The invention also provides application of the self-expanding stent as an iliac vein stent.

The invention also provides a preparation method of the self-expanding stent, which comprises the steps of cutting a tube material by laser and removing redundant parts of the tube material to obtain a hollow tubular structure with the waveform rod and the connecting part integrated, wherein the tube material is made of the shape memory material.

The self-expanding stent adopts the support structure that the single-spiral section and the double-spiral section are simultaneously designed on the single stent, and the connecting parts with different structures are designed on the single-spiral section and the double-spiral section along the circumferential direction, so that the stent has different flexibilities and extrusion resistance in the two sections, the single-spiral section has better extrusion resistance relative to the double-spiral section, and can well support a narrow lumen, the double-spiral section has better flexibility relative to the single-spiral section, and can fully adapt to the lumen section with complex bending, so that the stent can better adapt to the shape of a blood vessel, and better adherence performance is realized.

The self-expanding stent can also be provided with an annular supporting structure at the front side of the single spiral section, so that the anti-extrusion performance and the anchoring capability of the stent at the front end are further enhanced, and the incidence rate of stent release forward jump is reduced. And when the front end of the bracket needs to be designed with the bevel connection, the annular supporting structure is an inclined ring, and the bracket can obtain the required bevel connection angle without influencing the lift angle setting of the single spiral section by adjusting the waveform size of the inclined ring along the circumferential direction.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings.

FIG. 1 is a schematic structural view of an embodiment of a self-expanding stent of the present invention;

FIG. 2 is a schematic view of the embodiment of the self-expanding stent of FIG. 1 after being rotated at an angle along its central axis;

FIG. 3 is a schematic structural view of the embodiment of the self-expanding stent of FIG. 1 rotated by another angle along its central axis;

FIG. 4 is a plan view of the embodiment of the self-expanding stent of FIG. 1, wherein portions A, B are segments of a wave shaped rod self-closing and forming a closed loop, respectively;

FIG. 5 is a cut-line plan deployment view of the stock tubing of the embodiment of the self-expanding stent shown in FIG. 1;

FIG. 6 is an enlarged schematic view of the first connecting member;

fig. 7 is an enlarged schematic view of the second connecting member;

FIG. 8 is a schematic view of the self-expanding stent of the embodiment of FIG. 1 in position in the left common iliac vein;

FIG. 9 is an X-ray image of a self-expandable stent placed in the left common iliac vein of an experimental rabbit according to an embodiment of the present invention, wherein the left image A shows that the stent is released from the front portion and the right image B shows that the stent is completely released;

FIG. 10 shows a fixture for testing radial support force of a bracket;

FIG. 11 is an anatomical photograph of a self-expanding stent placed in the left common iliac vein of an experimental rabbit according to an embodiment of the present invention, showing the blood vessel and the stent cut off in the axial direction.

It should be noted that fig. 1-3 hide the stent structure on the side opposite the viewing direction for clarity in showing the stent structure of the illustrated embodiment.

In the drawings, reference numerals are explained as follows:

100. a first helical section; 200. a transition zone between the first helical section and the second helical section; 300. a second helical segment; 400. obliquely placing a ring;

110. a transition region at the other end of the first spiral section; 310. a transition region at the other end of the second spiral section;

610. a first connecting member; 620. a second connecting member.

201 and 202 are respectively the upper end and the lower end of the transition region 200 along the circumferential direction of the stent;

311 is a region where two wave bars of double helix in the transition region shown as 310 are merged into one wave bar; 312 is the region where one of the wave bars merged with segment B in the transition region shown in 310; 313. a closed loop with no free end in the transition region shown at 310;

511. 512, 513 and 514 are respectively four X-ray nontransmissive material markers arranged at an elliptic bevel at the front end of the bracket, wherein 511 and 513 are positioned at two end points of the major axis of the ellipse of the bevel, and 512 and 514 are positioned at two end points of the minor axis of the ellipse of the bevel;

521. 522 are two markers of X-ray opaque material disposed at the circular riser at the rear end of the holder, respectively, and 521 and 522 are located at the two ends of one diameter of the circle of the flat nozzle.

In fig. 8, 1 is a self-expanding stent, 701 is the inferior vena cava, 702 is the left common iliac vein, 703 is the right common iliac vein, 704 is the right common iliac artery.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Self-expanding stent

Example 1

The present embodiments provide a self-expanding stent having two different types of helical segments arranged axially therealong in a hollow tubular shape, wherein a first helical segment comprises a single helix and a second helical segment comprises a double helix of two parallel helices. Referring to fig. 1-3, 100 and 300 respectively show a first helical segment comprising a single helix and a second helical segment comprising two parallel double helices.

And the single spiral line and the double spiral line extend circumferentially around the central axis of the pipe shape in the same direction, the double spiral lines are combined into a single spiral line in a transition area between the single spiral line and the double spiral line, and the single spiral line and the double spiral line are respectively closed in the other transition area along the pipe shape in the circumferential direction at the other ends of the single spiral line and the double spiral line to form a closed ring without a free end.

Specifically, in the transition region between the first spiral section and the second spiral section of the present embodiment, which is shown in the region 200 in fig. 1, the two wave bars constituting the double spiral line are merged into one wave bar from the end 201 to the end 202, the wave height of the first wave of the wave bar is equal to or close to the sum of the wave heights of the two wave bars at the upper end of the wave bar, and the wave height of the wave bar gradually decreases towards the end 202 until the wave bar approaches and extends to the wave bar of the first spiral section. The 200-area unfolded whole body is a quadrangle with two waists having the same slant angle and different inclination angles, and obviously, the two bottoms of the quadrangle are different in size.

Similarly, in the transition region at the other end of the second spiral section, see the region 311 shown in fig. 2, the two wave-shaped rods of the second spiral section, which form a double spiral line, are combined into one wave-shaped rod at the other end, and the wave height of one wave of the second spiral section increases suddenly at a certain position in the region 312, see fig. 3, the wave height of the subsequent wave-shaped rod decreases gradually along the circumferential direction to form a flush pipe orifice, and finally, the subsequent wave-shaped rod is closed at the wave-shaped position where the wave height increases suddenly to form a closed ring 313. A more intuitive presentation can be seen in fig. 4.

In the transition region at the other end of the first helical section, a corrugated rod forming a single helix can also be closed in the same manner to form a closed ring forming a flush orifice. However, the present embodiment selects the closed loop of the first helical segment to form a slant closed loop by adjusting the wave height of the waveform, i.e. the closed loop is deviated to one side of the radial section of the tube shape to form a slant orifice, see the area 110 shown in fig. 2.

Adjacent turns of the single helix are connected by a first connecting member 610, and any one of the two helices is connected to its adjacent helix by a second connecting member 620. The first connecting member and the second connecting member are each a plurality of members distributed along the circumferential direction of the tubular shape.

The helical wire may have a width in its axial direction to provide the stent with greater radial support. Obviously, the larger the axial width is, the larger the radial supporting force is, but the compliance of the helical line integrally attached to the inner wall of the pipe cavity is reduced, and the attached area is reduced. The spiral line of the present embodiment is formed by a spiral-shaped corrugated rod having a corrugated structure arranged along the length direction thereof.

In order to make the performance difference between the two spiral sections meet specific requirements, the wave forms of the previous spiral turn and the next spiral turn of the single spiral line are staggered in the circumferential direction of the tubular body, and the wave forms of the previous spiral turn and the next spiral turn of the double spiral line are parallel in the circumferential direction of the tubular body. The front and the rear waveforms are staggered in the circumferential direction of the pipe shape, so that the bracket has more uniform radial supporting force in the section, and the anti-extrusion performance is enhanced; on the contrary, the front and back waves are arranged in parallel in the circumferential direction of the tube, so that the stent has uniform flexibility in the axial direction of the section and better compliance.

The waveform of the wave-shaped rod of the present invention can be selected from the prior art, such as a Z-shaped wave, an omega-shaped wave, a sine wave, etc., and the structural parameters of the wave-shaped rod are selected and adjusted corresponding to the waveform and the size of the stent to obtain the required structural performance of the stent. The shape of the first and second connecting members may also be selected as desired, such as linear, arcuate, S-shaped, and the like.

In this embodiment, the waveform of the stent waveform rod is a Z-shaped waveform, see fig. 1-3; the first connecting part and the second connecting part are dumbbell-shaped with two wide ends and a narrow middle part, referring to fig. 6 and 7, the two ends are fused with wave crests or wave troughs of the wave-shaped rod, the whole body is circular or elliptical, and the middle width is not changed. Obviously, in some cases, the intermediate width of the first connecting part and the second connecting part may be gradually varied.

Example 2

Based on example 1, a further improvement of this embodiment is that the lead angle of a single helix is not greater than the lead angle of a double helix in the unconstrained stable free-expansion state of the stent. The lead angle refers to the inclination angle of a tangent line of a point on the spiral line to the radial section of the support. Referring to fig. 1, the complementary angle of the lead angle of the double helix of the second helix segment 300 is α, that is, the helix angle of the double helix is α, and the complementary angle of the lead angle of the single helix of the first helix segment 100 is β, that is, the helix angle of the single helix is β, and α is less than or equal to β.

Example 3

Based on embodiment 1 or embodiment 2, the present embodiment is further improved in that adjacent turns of a single spiral are connected by a first connecting part to the nearest peaks and valleys, and any spiral in a double spiral is connected by a second connecting part to the nearest two peaks or two valleys. The length of the first connecting part is significantly smaller than that of the second connecting part, so that the extrusion resistance and the flexibility of the two spiral sections are respectively further enhanced.

Referring to fig. 1-4, the first connecting member is angled with respect to the axial direction of the stent and the second connecting member is substantially parallel to the axial direction of the stent.

Example 4

Based on embodiment 3, the present embodiment is further improved in that, along the axial direction of the stent, adjacent first connecting parts in a single spiral line are arranged in a staggered manner, and adjacent second connecting parts in a double spiral line are arranged in parallel, as shown in the expanded view of the stent in fig. 4.

Example 5

Based on embodiment 1, the present embodiment is further improved in that the present embodiment proposes a self-expanding stent suitable for a blood vessel.

Based on the physiological anatomical structure of the blood vessels of human or animal bodies, particularly the blood vessels of inferior vena cava, the wave-shaped rod is selected to have a Z-shaped wave with the wave height of 1-5 mm, and the wave height refers to the vertical distance between adjacent wave crests and wave troughs. Moreover, the wave-shaped rod can have 10-25 wave crests or 10-25 wave troughs on every 360-degree spiral turn; the width of the body of the wave-shaped rod is 0.1-0.4 mm, the width d1 of the first connecting part is 0.2-0.5 mm, and the width d2 of the second connecting part is 0.1-0.3 mm, see fig. 6 and 7; the length of the first connecting part along the axial direction of the bracket is not more than 2 mm; the length of the second connecting part along the axial direction of the bracket is greater than the wave height of the corrugated rod, and the difference between the length and the wave height is not greater than 2 mm; the number of the first connecting parts and the second connecting parts distributed along the circumferential direction of the pipe shape every 360 degrees is 3-8 respectively.

Selecting different combinations of values within the above parameters may result in stents of various sizes, and stents of different sizes may also have different lengths, such as the total length of the stent, the length of the first helical segment, the length of the second helical segment, etc., as desired. The total length of the bracket of the embodiment is selected to be 50-120 mm. The length of the double spiral section 300 is 30 mm-100 mm. If the second helical section is too long, the stent is at risk of being accumulated in the releasing process, and the waveform arrangement of the stent is disordered after the stent is released into a blood vessel.

Example 6

Based on embodiment 5, the present embodiment is further improved in that the width of the body of the wave shaped lever is larger than the width of the first connecting part and the second connecting part. And the length of the first connecting part along the axial direction of the bracket is not more than 1 mm; the length of the second connecting part along the axial direction of the bracket is greater than the wave height of the corrugated rod, and the difference between the length of the second connecting part and the wave height is not more than 1 mm.

Example 7

A further improved embodiment is provided on the basis of example 1, in which the self-expanding stent of this embodiment further comprises a non-helical section 400 comprising an angled loop around the central axis of the tubular shape, the angled loop being formed by an annular wave-shaped rod, the angled loop and the closed loop of the single helix within the first helical section being co-biased to one side of the radial cross-section of the tubular shape, see fig. 1-3.

The waves of the slanted rings and the closed rings of the first helical section are staggered in the circumferential direction of the tube and connect the closest peaks and valleys thereof by first connecting means, see fig. 1-4. The inclined ring is fixedly provided with four markers to indicate the direction of the inclined opening of the bracket.

Obviously, the non-helical section may also be provided with a plurality of parallel angular rings, which are also connected by corresponding connecting members, in the preferred embodiment one.

The size of the waveform of the inclined ring along the circumferential direction can be adjusted to ensure that the stent obtains the required bevel angle, which is shown as kappa in figure 1. To achieve suitable radial support and axial compliance, the helix angles β, α typically need to be selected within a certain range, and in some cases may result in the helix angle β not matching the bevel angle of the bevel of the lumen, e.g., the bevel flare of the left common iliac vein which is oblique to the opening. The addition of the inclined ring can ensure that the stent obtains a required bevel angle at the front end, thereby meeting the requirement of the angle of a physiological anatomical structure of a special blood vessel. Also, the canted ring has a relatively more stable angle of the bevel under compression and provides enhanced support at the front end. In general, k > β > α is chosen.

Example 8

Based on embodiment 7, the present embodiment is further improved in that the sum of the lengths of the non-spiral section 400 and the first spiral section 100 is smaller than the length of the second spiral section 300. Wherein the sum of the lengths of the non-spiral section 400 and the first spiral section 100 is 10mm to 60 mm.

Example 9

Based on embodiment 1 or embodiment 7, the present embodiment is further improved in that, in the transition region, one wavy rod, which is a combination of two wavy rods, has a tendency that the wave height gradually decreases and the width of the rod also gradually decreases as a whole in the circumferential direction of the stent. The variation of the width of the rod can adjust the difference of different waveform angle expansion capacities caused by different wave heights when the diameter of the stent is increased, and the support capacity of radial approach in the transition region is obtained.

Example 10

Based on any of the embodiments described above, this embodiment proposes a further improvement, wherein the diameter of the self-expanding stent in the unconstrained, freely expanded state is monotonically tapered along the axial direction thereof, and the diameter of the first helical section is larger than the diameter of the second helical section as a whole. Namely, the longitudinal section of the bracket is in a cone shape with a large front end and a small back end;

for the self-expanding stent applicable to the iliac vein, the diameter of the front end of the self-expanding stent is 10-18 mm, and the diameter of the rear end of the self-expanding stent is 10-14 mm.

Summary of the invention

Obviously, in the above embodiment, the multiple spiral lines are selected as the double spiral lines. However, based on the above description, a person skilled in the art may also select other forms of multi-helix, such as three, four or more helices in parallel and in the same direction, which accordingly may consist of three corrugated rods, four corrugated rods or more corrugated rods. And combining the plurality of wave-shaped rods of the multi-helix in the transition region into one wave-shaped rod in pairs until all the wave-shaped rods are finally combined into one wave-shaped rod.

Applications of

Referring to fig. 8, the position of the self-expanding stent of the embodiment 1 after the release of a left common iliac vein is shown, the physiological anatomical structure of the left common iliac vein is shown in 702, the front end orifice of the self-expanding stent is a bevel opening, and a plurality of markers are arranged on the bevel opening surface to indicate the position of the bevel opening.

For the self-expanding stent of example 7, the front end of the first helical section 100 is further provided with the non-helical section 400, the oblique ring of the non-helical section 400 forms an oblique mouth, and the elliptical oblique mouth surface is provided with four markers to indicate the position of the oblique mouth, so that the self-expanding stent can be accurately placed in the horn mouth of the left common iliac vein which enters the inferior vena cava 701 and is stably anchored.

Preparation method

Referring to fig. 5, there is shown a cut view of a self-expandable stent according to an embodiment of the present invention, wherein the tube material is a nitinol tube, fig. 1 to 3 are views of the stent according to the embodiment of the present invention at different angles after expansion, fig. 4 is a schematic view of the expanded plane thereof, and the parameters of the corrugated rods and the connecting rods selected according to the different specifications of the stent are described in example 5, example 6 and example 8.

After laser cutting, excess material in the gap between the wave bar and the connecting bar is removed, and the self-expanding stent with the required determined diameter in the free expansion state is obtained through expansion and heat treatment.

Testing

Test of support positioning and anchoring performance

The self-expanding stent shown in figure 1 is placed in the left common iliac vein of a sheep (with the weight of 46Kg) through an interventional operation, the diameter of the opening of the left and right iliac veins is measured to be 10-11 mm after angiography, and the diameter of the far end is about 9mm, so that a 1210060-specification stent is adopted, namely the diameter of the front end of the stent is 12mm, the diameter of the rear end of the stent is 10mm, the front end of the stent is correspondingly arranged at the opening ends of the left and right iliac veins, and the rear end of the stent is correspondingly arranged at the far ends of the left and right iliac veins. The left X-ray image a of fig. 9 shows the position of the stent when the front portion of the stent is released, and the right X-ray image B of fig. 9 shows the position of the stent after the stent is completely released.

After the stent implantation, the sheep were sacrificed after the raising environment had freely moved for one month, and the iliac veins were dissected, as shown in fig. 11, the stent position did not shift, the stent endothelialization in the blood vessel was good, and the stent front end did not enter the inferior vena cava.

Support performance test

Test method

The radial supporting force of the stent is measured in a compression mode to represent the supporting performance of the stent. The fixture shown in fig. 10 is adopted, the bracket is placed on an arc-shaped surface between an upper fixture and a lower fixture, the lower fixture is fixed, the upper fixture moves downwards, the moving speed is 20mm/min, the inlet force (the dead weight of the fixture is removed, and the force generated after the fixture starts to contact) is set to be 0.1N, the displacement is calculated after the inlet force is reached, the movement is stopped after the fixture is compressed downwards for 3mm, and the upper fixture moves upwards at the speed of 50mm/min after the fixture is kept at the position for 10 seconds until the fixture is completely withdrawn. And recording the relation between the compression amount and the force of the bracket on the upper clamp in the process, and taking the peak value of the force as the radial supporting force of the bracket.

The radial supporting force of the self-expanding stent shown in fig. 1 and the control stent was measured according to the above-described method, and the test results were as follows (the results were averaged after a plurality of measurements).

The reference substance is a Zilver bracket of COOK company, has a structure similar to an E-luminexx bracket and is also a hollow bracket formed by cutting a metal tube, the periphery of the bracket consists of a plurality of groups of annular wave-shaped rods which are axially arranged in parallel and connecting rods for connecting adjacent wave-shaped rods, and the staggered rods which surround the hollow holes are integrally connected.

The measured specification of the stent, the diameter of the front end of the stent shown in the invention figure 1 is 14mm, the diameter of the rear end is 12mm, and the length of the stent is 60 mm; the control had a diameter of 14mm at both the front and rear ends and a length of 65 mm.

The stent of the embodiment of the invention is a cut open-loop stent, the stent has small shortening under the condition of receiving compression, and the length of the stent cannot be extended or shortened even under the condition that the lumen of the stent is flattened by non-radial compression. Therefore, the length of the bracket with the structure can not change after being compressed, the front end and the rear end of the bracket can not shift due to expansion, the bracket has better anchoring force, avoids potential risks caused by the fact that the front end of the bracket stretches into the inferior vena cava, and is safer.

Claims

1. The utility model provides a self-expanding support, is including forming the tubular bearing structure of cavity, its characterized in that, bearing structure is the bevel connection at the tubular one end oral area of cavity, the terminal surface of bevel connection is one and puts the ring constitution to one side, it is in to one side put the ring the tubular circumferential direction of cavity is continuous.

2. A self-expanding stent according to claim 1, wherein: the angle of the oblique opening is matched with the angle of the oblique opening of the left common iliac vein in the human body.

3. A self-expanding stent according to claim 1, wherein: the supporting structure comprises a plurality of inclined rings, and the inclined rings forming the end faces of the inclined openings are connected with another inclined ring through connecting parts.

4. A self-expanding stent according to claim 1 or 3, wherein: the inclined ring is formed by annular wavy rods.

5. A self-expanding stent according to claim 4, wherein: the wave-shaped rods forming the inclined ring have different wave-shaped size distribution along the circumferential direction and form a basically flush surface on the end surface of the inclined opening.

6. A self-expanding stent according to claim 4, wherein: the support structure comprises a spiral support section in the middle of the hollow pipe shape, and a transition section support structure is arranged between the spiral support section and the inclined ring.

7. A self-expanding stent according to claim 6, wherein: the spiral supporting section is mainly composed of a spiral-shaped wavy rod with a lead angle different from that of the bevel opening.

8. A self-expanding stent according to claim 6, wherein: the transition section supporting structure comprises a closed ring which is circumferentially and self-closed at one end of the closed ring by a spiral line-shaped wave rod, the inclined ring and the closed ring are connected through a connecting part and commonly deflect to one side of the radial section of the hollow pipe shape, and included angles of the inclined ring and the closed ring and the radial section are different.

9. A self-expanding stent according to claim 1, wherein: the diameter of the self-expanding stent in an unconstrained, freely expanded state is monotonically graded along the axial direction thereof, and has a maximum diameter at the bevel.

10. A self-expanding stent according to claim 1, wherein: the support structure is a unitary structure cut from a tube of shape memory material.