WO2011093608A2

WO2011093608A2 - Biometal strip-type stent for therapy of cerebral aneurysm

Info

Publication number: WO2011093608A2
Application number: PCT/KR2011/000307
Authority: WO
Inventors: 한문희; 고재영; 김우경; 임성우; 정민영
Original assignee: 주식회사 뉴로벤션
Priority date: 2010-01-29
Filing date: 2011-01-14
Publication date: 2011-08-04
Also published as: KR20110088975A; WO2011093608A3

Abstract

The stent of the present invention comprises two or more wires which are rotated and coiled in the spiral shape and are extended and braided in the longitudinal direction thereof. The wire is densely braided in the center part of the stent so that the density of wire in the center part of the stent can be greater than that at both ends of the stent. The density of wire changes continuously between both ends of the stent and the center part thereof. Additionally, the stent of the present invention comprises a plurality of wires which are rotated and coiled in the spiral shape and are extended and braided in the longitudinal direction thereof, wherein there are two or more wires and a core portion formed from radiopaque substances is inserted in the center of each wire.

Description

Bio-metallic thin stents for the treatment of cerebral aneurysms

The present invention relates to a stent for the treatment of cerebrovascular disease (cerebral vascular disorder), specifically inserted into a blood vessel (blood vessel) to maintain normal blood flow and embolism (emboli into the interior of the neovascular aneurysm (neurovascular aneurysm) And stents that block blood flow.

In general, vascular disease is a term used to refer to a disorder of blood vessels. Sudden cerebrovascular disorder causes local neuropathy symptoms such as loss of consciousness, hemiplegia, and speech impairment, and in severe cases, death. It is a disease.

Cerebrovascular disease is represented by ischemic diseases such as cerebral infarction caused by blood circulation disorder due to blood clots accumulated in narrowed cerebral arteries and subarachnoid hemorrhage caused by cerebral aneurysms in which some of the blood vessels swell. There is a hemorrhagic disease.

In order to treat such cerebrovascular disease, balloon plastic surgery, such as a balloon catheter, is used to insert a balloon into the blood vessel, and the balloon is fixed to the diseased portion to expand the balloon to expand the vascular disease portion. Surgery of this method has a problem such as causing pain or recurrence of the patient. In addition, since cerebrovascular disease is a high risk in the case of surgical treatment compared to other organs due to physiological characteristics, minimally invasive treatment method is required instead of direct surgery.

In order to overcome this problem, a stent formed of a metal mesh is inserted into the stenosis to enlarge the original blood vessel size or prevent embolism and blood flow from entering the cerebral aneurysm. A method using a stent to maintain blood flow is used.

These stents are used to prevent flow of blood or body fluids and to be inserted into the blocked area according to interventional procedures to normalize the flow or to block additional embolism and blood flow into the cerebral aneurysm if there is a disturbance in the flow of blood or body fluids. It refers to a tubular structure implant in the form of a metal mesh. An example of such a stent is disclosed in US Patent Application Publication No. 2005/0267568, filed May 25, 2005, published December 1, 2005, entitled "FLEXIBLE VASCULAR OCCLUDING DEVICE".

Stent intervention, a minimally invasive procedure using stents, involves the use of a small catheter, thin wire (guide wire), or stent-delivered delivery wire through a blood vessel under X-ray vision. After accessing to the vascular disease area, the passage of a metal stent, such as to normalize the flow of blood, or block the neck (neck) that is the entrance of the cerebral aneurysm to prevent the inflow of embolism and blood flow to prevent blood flow It is a normalizing treatment.

In order for the stent to function stably during the procedure or after insertion into the body, in the case of a stent made of a shape memory material such as nitinol, flexibility and resistance to resistance to blood vessel pressure without collapse of the stent in the vessel Radial resistence must be excellent, and the contact area with blood vessels is small, and uniform structural arrangements are required to minimize the ratio of voids after expansion. In addition, when the stent functions to block the neck of the cerebral aneurysm, characteristics such as embolism and blood flow are increased to prevent the stent from passing through the outer peripheral surface of the stent.

Referring to Figures 1 and 2 will be described with respect to the conventional stent.

FIG. 1 is a view illustrating a stent 1 which blocks a neck portion so that embolism and blood flow do not flow into an aneurysm (AN: aneurysm) where embolism (EM) is accumulated in a cerebrovascular vessel. 2 is an enlarged view of the stent 1.

As shown, the stent (1) for treating hemorrhagic vascular disease is to block the neck portion of the cerebral aneurysm (AN) swelling blood vessels that additional embolism and blood flow into the cerebral aneurysm (AN) Prevent.

Here, as shown in FIG. 2, the stent 1 spirally braids multifilament metal yarns, or a plurality of metal strand wires 3 similar to a polymer. It is manufactured by braiding. During braiding, each wire 3 is rotated and wound so as to have a constant wire pitch, so that a void (H: Hole), which is a blank area of the wire 3, exists on the outer peripheral surface of the stent 1.

Here, in the case of the stent (1) used for hemorrhagic diseases of the cerebrovascular vessels in order to prevent the inflow of embolism and blood flow through the neck while the stent (1) is located in the neck (Neck) of the cerebral aneurysm (AN) The void region H has a density that is minimized.

In a conventional stent, since the entire part of the stent is designed and manufactured to have a constant density, shape memory such as Cr-Co alloy, stainless steel, or nitinol used as the main material of the stent is used. In addition to the need for a large amount of alloy, there is a serious problem that the flexibility of the stent is significantly reduced because the stent is made of high density in the portion other than the neck portion, which is the entrance of the cerebral aneurysm.

In addition, the uniform use of the shape memory alloy made of nitinol prevents the radiopacity of the material, and thus, computed tomography (CT) and magnetic resonance imaging (MRI) during or after the procedure. There was a disadvantage that it was difficult to check the stent's position under the photography.

Therefore, the present invention provides a stent that effectively blocks additional embolism and blood flow into the cerebral aneurysm site while maintaining elasticity, such as anti-pressure resistance, flexibility, and circular resilience required for the stent.

The present invention also provides a stent for facilitating positioning in the blood vessel by radiation such as X-rays.

In addition, the present invention provides a delivery wire inside the catheter having a function of securing a reposition when the stent is not mounted at a desired position.

According to a first embodiment of the present invention, it includes two or more wires which are rotated in a spiral shape and extended in a longitudinal direction and braided,

The wire is densely braided at the center of the stent such that the wire density at the center of the stent is greater than the wire density at both ends of the stent,

A stent is provided in which the wire density between both ends of the stent and the center portion of the stent varies continuously.

The central portion occupies an area of 20% or more and 50% or less with respect to the length of the stent in the center of the stent.

In addition, the angle at which the two or more wires cross each other in the central portion is 160 degrees or more.

According to a second embodiment of the present invention, it includes two or more wires which are rotated and wound in a spiral shape and extended in a longitudinal direction and braided,

A first region braided to have a first wire density from one end of the stent,

A second region braided from the first region to increase wire density,

A third region in the center of the stent that is connected to the second region and braided to have a second wire density,

A fourth region braided to reduce wire density from the third region,

A stent is provided that extends from the fourth region and includes a fifth region braided to have a third wire density up to the end of the stent.

The first wire density and the third wire density are the same.

The third region occupies an area of 20% or more and 50% or less with respect to the length of the stent in the central portion of the stent.

In addition, an angle at which the two or more wires cross each other in the third region is 160 degrees or more.

In addition, an angle at which the two or more wires cross each other in the first region and the fifth region is less than 160 degrees.

According to a third embodiment of the present invention, a plurality of wires are braided to rotate in a spiral shape and extend in a longitudinal direction to be braided.

The stent is provided with two or more wires and a core portion formed of a radiopaque material is inserted in the center of each of the wires.

The core portion has a circular cross section having a diameter of 20% or more and 60% or less of the wire diameter.

The radiopaque material is any one of platinum, gold, palladium, or tantalum.

In addition, the stent is densely braided at the central portion of the stent such that the wire density at the center portion is greater than the wire density at both ends of the stent.

The stent according to the present invention can effectively block the inflow of additional embolism and blood flow to the cerebral aneurysm site while maintaining the properties of anti-pressure, flexibility, and elasticity required for the stent.

In addition, the stent according to the present invention can easily secure the position of the intravascular stent by improving radiopacity.

1 and 2 is a conceptual diagram showing a conventional stent,

3 is a view of a stent according to a first embodiment of the present invention,

4 is a view showing the density change of the stent wire according to the first embodiment of the present invention,

5 is a view of a stent according to a second embodiment of the present invention,

6 is a view showing the density change of the stent wire according to the second embodiment of the present invention,

7 is a cross-sectional view of the wire used in the stent according to the embodiment of the present invention,

8 is an enlarged view of a portion of another embodiment of a wire used in a stent in accordance with an embodiment of the present invention.

Hereinafter, a stent according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the following description refer to like elements or components. The following specific examples are only illustrative of the stent according to the present invention, and are not intended to limit the scope of the present invention.

3 is a view of a stent according to a first embodiment of the present invention.

As shown in FIG. 3, the stent 10 according to the first embodiment of the present invention is manufactured by braiding a plurality of wires 13. During braiding, two or more wires 13 are rotated and wound in a spiral shape and extend in the longitudinal direction to form a generally cylindrical mesh shape.

At this time, the cylindrical stent 1 has a circular cross section perpendicular to the longitudinal direction, which corresponds to the cross sectional shape of the blood vessel.

The stent 10 is formed by braiding a plurality of wires 13, and the voids H between the wires 13 may be different from each other on the outer circumferential surface of the stent 10. Low, on the contrary small, means high wire density.

The stent 10 used for hemorrhagic cerebrovascular disease has a high density of wire 13 in these portions to prevent additional embolism and blood flow into the intracranial aneurysm (AN). It must be formed.

For this purpose, it is preferable that the oblique angle is 160 degrees or more, preferably 161.54 degrees at the portion where the wires 13 cross each other in the central portion CE directly facing the neck of the cerebral aneurysm. When the wire 13 is at an obtuse angle of 160 degrees or less, the embolism or the blood flow can move through the gap H between the wires 13, and the efficiency of blocking the embolism or the blood flow is lowered. Can not function as). Since the area of the cerebral aneurysm AN does not come into contact with the neck of the cerebral aneurysm in the region other than the central portion CE, the angle at which the wire 13 intersects may be less than 160 degrees as an obtuse angle.

Here, the predetermined distance may be freely selected by those skilled in the art, but the central portion CE, which is in contact with the site of the cerebral aneurysm, should occupy the predetermined distance with the highest density in the stent 10, which is the cerebral aneurysm (AN). It is in order to achieve the function of the stent 10 by preventing direct inflow of embolism and blood flow in direct contact with. To this end, the central portion CE may have a blood impermeable density.

The central portion CE may be 20% or more and 50% or less with respect to the entire length of the stent 10. If the central portion (CE) is reduced to less than 20%, the central portion (CE) of the cerebral aneurysm may not be sufficiently blocked to prevent further embolism and inflow of blood flow. (10) Problems such as waste of material, difficulty in manufacturing, and reduction of elasticity occur.

According to the first embodiment of the present invention, as shown in FIG. 3, the stent 10 of the present invention is braided into a cylindrical shape having a length of 25.86 mm and a diameter of 5 mm using a wire 13 having a diameter of 0.05 mm. This stent 10 includes A, B, C, and D portions in which the pore area and the wire density vary continuously in the longitudinal direction.

In part A, which is a distal end portion of both sides of the stent 10, the space H where the plurality of wires 13 meets has a rhombus shape, the long diagonal of which is 0.785 mm and the short diagonal is 0.262 It may have a length of mm, and the obtuse angle of the portion where the wire 13 meets may be 143.09 degrees.

In addition, the portion B of the central portion CE of the stent 10 has the smallest width of the void and the highest wire density. In part B, the long diagonal of the rhombus has a length of 0.785 mm like A, but the short diagonal has a length of 0.131 mm, so that the void (H) is reduced. You can see that it is reduced to one half (the area formula of the rhombus (long diagonal length) * (short diagonal length) / 2 is half the length of the short diagonal). Here, the central portion CE of the stent 10 may have a predetermined wire density, and may have a density such that blood permeation is limited.

Next, in the C and D portions located between the A and B portions, the length of the long diagonal line is the same in the rhombus shape of the void H generated by the wire 13, but the short diagonal lines are 0.236 mm each. It gradually decreases from 0.145 mm to the B part of the center (CE). At this time, the obtuse angle of the portion where the wire 13 meets in the C portion and the D portion may be 146.53 degrees and 157.24 degrees, respectively.

In the longitudinal direction of the stent 10, the gap H gradually decreases from the A portion, which is the distal end of the stent 10, to the B portion, which is the center portion, and the wire density is gradually tightened while the wire 13 is gradually wound tightly. It means increasing gradually.

Here, the change of the wire density may vary continuously or intermittently in the longitudinal direction of the stent 10.

Specifically, each of the areas in the longitudinal direction of the stent 10 may have different sizes and wire densities of pores (H), Figures 4a and 4b from one end of the stent 10 to the entrance of the central portion (CE) The case where the wire density of the wire 13 changes continuously is shown, FIG. 4C shows the case where the wire density of the wire 13 changes intermittently. FIG. 4D illustrates a case where the portion where the wire density changes from one end of the stent 10 to the entrance of the central portion CE is limited. 4A to 4D, the horizontal axis means the length of the stent 10, and the vertical axis means the wire density.

4A illustrates a case where an inflection point of the wire density exists in a portion from one end of the stent 10 to the central portion CE, and FIG. 4B illustrates a case where the inflection point does not exist. A, B, C, and D on the graph indicate the A, B, C, and D portions of FIG.

In addition, FIG. 4C is a case where the wire density changes in a stepwise manner, in which the wire densities are kept constant in the A, B, C, and D portions, and the wire density is intermittently changed between the portions.

Next, in FIG. 4D, the wire density (first density) is kept constant at the end portion of one side of the stent 10 (part A, the first region), and there is an area where the density increases after a predetermined distance (C And part D, the second region), followed by the central portion (part B, the third region) having the highest density (second density). Of course, both ends of the stent 10 may be formed symmetrically with respect to the center portion CE, so that the area where the wire density decreases (fourth area) and the other end where the density is maintained constant (third density) again. There may be a region (a fifth region), and the wire density of the first region and the fifth region may be the same.

Here, the intersection of the wires 13 with each other in the third region may be 160 degrees or more at an obtuse angle in consideration of the efficiency of embolization and blood flow blocking, and the first and fifth regions may be cerebral aneurysms (AN). Since it does not touch the neck portion of the neck, the angle at which the wire 13 intersects may be less than 160 degrees at an obtuse angle.

Here, the predetermined distance can be freely selected by those skilled in the art, but the central portion CE facing the neck of the cerebral aneurysm has the highest wire density in the stent 10 and faces the neck of the cerebral aneurysm while facing the neck of the cerebral aneurysm. Must occupy a predetermined distance or more so as to block the inflow of embolism and blood flow through the part, in order to achieve the function of blocking the embolism and blood flow of the stent 10. Here, the central portion CE may have a density such that blood penetration is limited.

The central portion CE may be 20% or more and 50% or less with respect to the entire length of the stent 10. In this case, when the central portion (CE) is reduced to less than 20%, the central portion (CE) does not sufficiently block the neck of the cerebral aneurysm, preventing additional embolism and inflow of blood flow, and the central portion (CE) is 50% or more. This results in waste of the stent 10 material, difficulty in manufacturing, and reduction of elasticity.

5 shows a stent according to a second embodiment of the present invention. In the following description, the same reference numerals refer to the same members or parts, and the description of the same parts will be omitted.

In the second embodiment of the present invention, unlike the case of the first embodiment, the central portion CE of the stent 20 is formed to have the same high wire density as the B portion of the first embodiment, and in other parts, the A of the first embodiment is used. It is formed to have the same low wire density as the part. In other words, in the second embodiment of the present invention, the distribution of the wire density is divided into two parts, and the density of the wire 23 is rapidly changed in the area between the two parts.

6 is a graph illustrating the distribution of wire density according to the second embodiment of the present invention.

Here, the angle at which the wires 23 intersect at the portion B may be 160 degrees or more as an obtuse angle, and since the first and fifth regions do not contact the neck portion of the cerebral aneurysm, the wire 23 is The intersecting angle may be less than 160 degrees at an obtuse angle.

Here, the predetermined distance between the wires can be freely selected by those skilled in the art, but the central portion CE which comes into contact with the neck of the cerebral aneurysm should occupy the predetermined distance with the highest density in the stent 20. This is to achieve the function of the stent 20 to block the embolus and blood flow into the cerebral aneurysm. To this end, the central portion CE may have a wire density such that blood permeation is limited. The central portion CE may be 20% or more and 50% or less with respect to the entire length of the stent 20. Here, if the central portion (CE) is reduced to less than 20%, the central portion (CE) of the stent is not able to effectively block the inflow of embolism and blood flow, when the central portion (CE) is more than 50% of the stent 10 material Waste and manufacturing difficulties arise.

Here, in the central portion CE directly contacting the neck of the cerebral aneurysm, the angle at which the wires 13 cross each other is preferably at least 160 degrees at an obtuse angle. When the angle at which the wires 13 intersect is less than 160 degrees at an obtuse angle, the embolism and blood flow can move through the gap H between the wires 13, thereby reducing the efficiency of blocking the embolism and blood flow, thereby stent 10 You will not be able to function as.

In the second embodiment of the present invention, the space H formed by crossing the plurality of wires 23 in the portion B has a rhombus shape, and the length of the long diagonal of the rhombus shape is 0.785 mm, and the length of the short diagonal is Is 0.131 mm, and the angle at which the wires 23 intersect may be 161.54 degrees at an obtuse angle. Here, the central portion CE including the B portion is an area used to block the neck portion of the cerebral aneurysm (AN of FIG. 1), and reduces the length of the short diagonal of the air gap H to penetrate the blood. It may be formed to have a density of a limited degree. In addition, the space H formed by crossing the plurality of wires 23 in the portion A has a rhombus shape, the long diagonal of the rhombus shape is 0.785 mm, the length of the short diagonal is 0.262 mm, and the wire 23 The angle at which) crosses may be 143.09 degrees with an obtuse angle.

The number of wires used in the second embodiment of the present invention may be 32 or 48. The diameter of the wire is 0.002 inch for 32 pieces and 0.0015 inch for 48 pieces.

7 illustrates a wire used in a stent in accordance with the aforementioned embodiments of the present invention. As shown in FIG. 7, the wire 33 includes a core portion 35 in which a radiopaque material is formed in a central portion thereof. Nitinol, which is used as a wire material, is advantageous for securing the stent's elasticity, but it has a disadvantage in that it is difficult to confirm the position of the stent by X-ray radiation during or after the procedure because of high radiotransmittance. . However, the wire 33 of the present invention forms a core portion 35 having a radiopaque material formed in the center thereof.

The core portion 35 may have a diameter of 60% or less of the diameter of the wire 33. When the core part 35 has a diameter exceeding 60%, the elasticity of the wire 33 may be affected, which may cause the stent to deteriorate. In addition, when the core part 35 has a diameter of 20% or less of the diameter of the wire 33, it becomes difficult to secure the position of the stent by radiation such as X-rays, and therefore it is preferable to have a diameter of 20% or more.

8 shows another embodiment of a wire used in a stent according to the above embodiment of the present invention. As shown in FIG. 8, the stent is braided with a mixture of at least two types of first and

second wires

43 and 45, of which the first wire 43 is nitinol and the second wire 45. ) May be made of any one of the radiopaque material platinum, palladium or tantalum.

The second wire 45 using the radiopaque material preferably has a number of 5% to 30% of the total number of wires in the braided stent. When the second wire 45 has less than 5% of the total wires, it is difficult to secure the position of the stent by X-rays or the like, and when the second wire 45 has more than 30%, the entire stent 40 Influence of the elasticity of the stent 40 may cause a decrease in function.

Although the specific embodiments of the stent according to the embodiments of the present invention have been described above, this is merely an example, and the present invention is not limited thereto and should be construed as having the broadest scope in accordance with the basic idea disclosed herein. Those skilled in the art can change the material, size, etc. of each component according to the application field, it is possible to implement a pattern of a timeless shape by combining / replacing the disclosed embodiments, this also does not depart from the scope of the present invention. In addition, those skilled in the art can easily change or modify the disclosed embodiments based on the present specification, it is apparent that such changes or modifications are included in the scope of the present invention.

Claims

As a stent,

Comprising two or more wires that are spirally rotated and wound and extended in the longitudinal direction and braided,

The wire is densely braided at the center of the stent such that the wire density at the center of the stent is greater than the wire density at both ends of the stent,

A stent in which the wire density between the both ends of the stent and the central portion of the stent varies continuously.
The method of claim 1,

The central portion occupies an area of 20% or more and 50% or less with respect to the length of the stent in the center of the stent.
The method of claim 1,

The stent at which the at least two wires cross each other at the central portion is 160 degrees or more.
As a stent,

Comprising two or more wires which are braided to extend in a longitudinal direction while being wound in a spiral shape,

A first region braided to have a first wire density from one end of the stent,

A second region braided from the first region to increase wire density,

A third region in the center of the stent that is connected to the second region and braided to have a second wire density,

A fourth region braided to reduce wire density from the third region,

A stent comprising a fifth region connected to said fourth region and braided to have a third wire density to an end of said stent.
The method of claim 4, wherein

The stent and the third wire density are the same.
The method of claim 4, wherein

And the third region occupies an area of 20% or more and 50% or less with respect to the length of the stent in a central portion of the stent.
The method of claim 4, wherein

And the angle at which the two or more wires cross each other in the third region is greater than 160 degrees.
The method of claim 4, wherein

The stent of which the two or more wires cross each other in the first area and the fifth area is less than 160 degrees.
As a stent,

It includes a plurality of wires that are wound in a spiral shape and extended in the longitudinal direction and braided,

The stent having two or more wires, each of the core is inserted into the core portion formed of a radiopaque material.
The method of claim 9,

The core portion has a stent having a circular cross section having a diameter of 20% or more and 60% or less of the wire diameter.
The method of claim 9,

The radiopaque material is any one of platinum, gold, palladium, or tantalum.
The method according to any one of claims 9 to 11,

The stent is densely braided at the central portion of the stent such that the wire density at the center portion is greater than the wire density at both ends of the stent.