JP2000279530A - Stent and stent-type artificial lumen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a stent indwell following the shape of the wall of the curved internal lumen by constituting the stent of a linear member including a plurality of line parts and connecting parts connecting the respective lines to each other and providing, at least, a set of line part mutually adjoined to each other and having different lengths in a plurality of line parts. SOLUTION: The stent 10 to be inserted to an aortic dissection, or the like developed in a part when a part of a blood vessel is hurt in a curved part of the arcuate aorta is constituted of a looped linear member having such a zigzag structure that a plurality of line parts 11a, 11b having different lengths are connected to each other by connecting parts 12 and formed into a hollow cylinder shape as a whole. The lengths of the mutually adjoining line parts 11a, 11b are different so that, when inserted into the bent part of the lumen, the butting extent of the adjoining angular part of the stent 10 composed of the ends of the line parts 11a, 11b and the connecting parts 12 against the crest parts of other stent can be substantially reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stent (sten) which can be temporarily or (semi) permanently placed in a lumen (eg, a blood vessel) of an animal body including a human.
t) and artificial lumen (or stent graft, stent g)
raft).

More specifically, the present invention relates to a stent capable of exhibiting good adaptability even to a bent or curved part of a body lumen, and a method of forming the stent from a tubular body (a porous membrane or the like). )).

[0003] The stent or artificial lumen of the present invention can be formed by using a catheter or a sheath in a curved pathological lumen, from a site somewhat away from the pathological part, into the lumen. Remotely and spatially interval
This method can be particularly suitably used for a method of inserting at an interval (ie, interventionally). In this interventional technique, usually, a stent or an artificial lumen is inserted into a body lumen by remote control, and then reaches a diseased part. A tubular body or the like forming an artificial lumen is pressed and fixed in accordance with the bending curve of the body lumen.

[0004]

2. Description of the Related Art Temporarily or (half) in a body lumen such as a blood vessel
Many stents and vascular prostheses (or grafts) have been manufactured to treat stenosis and excessive dilatation of the lumen by permanent placement, and have already been applied to clinical practice, and in many cases, symptoms Giving improvements.

[0005] For a graft (stent and / or vascular prosthesis) into the lumen and a device (sheath, catheter, etc.) for inserting it into the lumen, US Pat. No. 5,282,824, No. 5,272,971, No. 5,2
No. 42,399, No. 5,219,355, No. 5,211,
No. 658, No. 5,201,757, No. 5,192,297
No. 5,190,058, No. 5,158,548, No. 5,147,370, No. 5,104,399, No. 5,0
Nos. 92,877, 5,078,726, 5,019,
No. 085, No. 4,990,151, No. 4,950,227
Nos. 4,913,141, 4,886,062, 4,820,298, 4,787,899, 4,6
No. 17,932, No. 4,562,596, No. 4,577,
Nos. 631, 4,140,126 and EP 539,237, 533,511, 5
No. 18,839, No. 518,704, No. 508,473
Nos. 505,686, 466,518 and 466,791 are known.

[0006] With respect to self-expanding stents that can be expanded within a body lumen (ie, a stent that expands without the need to apply an expanding force with another device such as a balloon), US Pat. No. 568, No. 5,019,0
No. 90, 5,035,706, 4,214,587
No. 5,800,456, 5,876,432, 5,843,176, 5,147,370, 4.9
Nos. 94,071, 4,776,337, and EP 575,719, 556,850.
Nos. 540,290, 536,610, and 418,365. Furthermore, Dupra
t et al. ”Self-expandable Metallic Stents for Sma
ll Vessels: An Experimental Evolution ”. Radiolog
y, Vol 162, pp 469-472, Feb. 198
7. Describes an artificial blood vessel in a small-diameter blood vessel.

[0007] Among these, stents used for lesions in the straight tube state of the trachea and aorta are described in US Pat. Nos. 4,580,568 and 5,035,706. Gianturco Z-stent type stents are commonly used in many facilities. Although other types of stents have been used in practice, they have excellent properties in terms of strength of self-expansion, expansion speed, and fixation of vascular prostheses.
Normally, this Gianturco Z-stent type stent is clinically most preferred.

[0008] However, a dedicated stent for inserting a bent portion and a stent used for an aortic aneurysm that occurs in a portion with a strong bent in a large lumen, such as a bent portion in a human aortic arch. Various devices have been devised for the device. However, each of the conventional devices has advantages and disadvantages, and a device suitable for a body lumen having various degrees of flexion has not yet reached a satisfactory level.

Japanese Patent Application Laid-Open Nos. 8-57057 and 8-895 describe techniques for using such bent portions.
No. 85, JP-A-8-317-990, JP-A-7-47134, and JP-A-10-277068 describe an artificial blood vessel that can be used also at a bent portion. Spiral stents which expand the self-expanding Gianturco Z-stent type stent spirally
U.S. Pat. No. 5,800,456, JP-A-7-50027
No. 2 discloses this.

Regarding these stents and vascular prostheses, US Pat. Nos. 4,580,568 and 5,035,
Gianturco with strong self-expansion power described in No. 706
Although the flexibility is improved as compared with the Z-stent type, a shape that sufficiently follows the curve of the wall of the body lumen that is completely bent cannot be obtained. For this reason, when these are used for treating an aneurysm generated in a bent portion, an endoleak phenomenon occurs due to “leakage” from an artificial blood vessel.

[0011]

Many of the conventional stents having a strong self-expanding force are basically Gianturco Z-
It is in the form of a stent. However, Gianturco
A disadvantage of the Z-stent type stent is that when it is inserted into a curved body lumen, the tip of the “corner” (connection portion of the stent) often protrudes abnormally. .

In such a case, the distal end of the bent portion of the Gianturco stent protrudes and strongly contacts the curved wall of the body lumen, and the protrusion often causes deformation of the wall of the body lumen. This is because the body lumen is not always perfectly straight. However, the Gianturco Z-stent type stent always deforms at the corresponding portion of the lumen because the tip of the bent portion at the end of the straight portion always comes into contact with the wall of the body lumen having a curved state. Often.

Although this phenomenon is often observed at the end of an artificial blood vessel in X-ray photography after a Gianturco Z-stent type stent is inserted, the inside of the body bent so that the distal end of the stent connection protrudes. It cannot be ignored that the bite into the wall of the lumen also contributes to the improvement of the fixing force of the stent. On the other hand, the movement of the tubular body, that is, the artificial blood vessel (graft), to be held by the stent is also a more serious phenomenon. For this reason, it is generally considered that the merit of preventing the movement of the artificial blood vessel by the bite of the stent is more important, and this “bite” phenomenon is hardly regarded as a problem clinically.

However, if the tissue in the body is always strongly compressed by the stent, this part gradually deteriorates in nutritional state and becomes degenerated or necrotic.
The wall may be mechanically deteriorated by a phenomenon such as thinning. For this reason, there is a good possibility that the patient will fall into a dangerous state after a long period of time since the insertion of the stent.

[0015] From such a viewpoint, a shape that sufficiently follows the curve of the curved wall of the body lumen is provided, and the curved wall of the body lumen does not deform due to the protrusion of the distal end of the connecting portion of the stent. There has been an urgent need to develop a stent that has a strong expansion force and a strong fixation force for an artificial blood vessel. This is because, in a body lumen (for example, a blood vessel), a straight portion is rather exceptional and very limited due to its structure, and many portions are more or less curved, and in particular, an aortic arch or the like. It is based on the reason that it is strongly bent or curved.

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stent and a stent-type vascular prosthesis which have solved the above-mentioned disadvantages of the prior art.

Another object of the present invention is to cause the stent to be placed in a shape that sufficiently follows the curved shape of the wall of the body lumen without causing the endoleak phenomenon due to leakage even at the bent part of the body lumen. It is an object of the present invention to provide a stent and a stent-type artificial vascular prosthesis.

[0018]

Means for Solving the Problems As a result of earnest research, the present inventor has found that the present invention has a completely different viewpoint from the conventional stent shape (a shape in which each stent emphasizes a state of being expanded at a linear portion in a body lumen). That is, the above object can be achieved by providing a stent with a shape that emphasizes a state where a plurality of stents are expanded at a curved portion in a body lumen (or a state where the stent is “folded” inside a sheath or the like). Was found to be extremely effective.

The stent (first embodiment) of the present invention is based on the above findings, and more specifically, has a loop shape having a zigzag structure including a plurality of line portions and a connection portion connecting the line portions to each other. And the plurality of line portions include at least one set of line portions adjacent to each other and having different lengths.

In the stent of the present invention having the above structure, since the plurality of line portions include at least one set of line portions which are adjacent to each other and have different lengths, the stent is inserted into the bent portion of the body lumen. At this time, the “mountain” -shaped portion formed by the connection portion at the end of the line portion batting (abuts with each other) with the “mountain” portion of another stent.
The degree can be substantially reduced. For this reason, when the stent of the present invention is used, it becomes easy for the stent to easily follow the shape of the bent portion of the body lumen.

As a result of further research by the present inventor, the above-mentioned "object" can be effectively achieved by making at least a part of the plurality of lines constituting the zigzag structure non-linear. I found that.

The stent (second embodiment) of the present invention is based on the above findings, and more specifically, has a loop shape having a zigzag structure including a plurality of line portions and a connection portion connecting the line portions to each other. And the plurality of line portions include a non-linear line portion in at least a part thereof.

When the stent of the present invention having the above configuration (second aspect) is inserted into a body lumen, the above-mentioned non-linear portion of the line portion is bent (compared to the straight portion). Since it fits well in the shape of the part, it becomes easy for the stent to easily follow the shape of the bent part of the body lumen.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to the drawings as necessary. In the following description, “parts” and “%” representing quantitative ratios are based on weight unless otherwise specified.

Prior to describing the details of the stent and the artificial lumen of the present invention, the latter, ie, the conventional stent, will be described first for the purpose of clarifying the difference from the conventional stent and the stent-type artificial blood vessel.

(Arterial System) First, as a typical example of an animal lumen, the arrangement of a human arterial system will be described. The schematic cross-sectional view of FIG. 1 shows a right common carotid artery, a left common carotid artery, a right subclavian artery, a left subclavian artery, a brachiocephalic artery, an ascending aorta, an arch aorta (aortic arch), a descending aorta, a right renal artery, and a left renal artery. Artery, right common iliac artery, left common iliac artery, right internal iliac artery, left internal iliac artery, right external iliac artery, left external iliac artery, right femoral artery, left femoral artery .

In the arch aorta, there are three side branches (ie, the brachiocephalic artery, the left common carotid artery, and the left subclavian artery) as shown in the schematic sectional view of FIG. It is an important blood vessel that bleeds into both arms. Therefore, when inserting a stent-shaped vascular prosthesis into the arch aorta, these side branches must not be blocked by the stent. There is a possibility that some of these side branches may be occluded by expanding inside the blood vessel. Furthermore, the arch aorta distal to the site from which the three side branches emerged is largely bent and transitions to the descending aorta. Curve tends to increase, and this is also a site where individual differences between individual patients are large.
In recent years, the rate of occurrence of an aneurysm in this curved portion has tended to increase.

FIG. 1 shows the state of the curve. Further, in the schematic sectional view of FIG. 2, a part of a blood vessel wall at a curved portion of the arch aorta is damaged, and aortic dissection 1 occurs,
An example in which an aortic aneurysm (dissecting aortic aneurysm) is caused by this is shown. In recent years, the occurrence of such dissecting aortic aneurysms has
It tends to increase rapidly.

FIG. 3 shows an ideal state in which the conventional stent-type artificial blood vessel 2 is inserted at the site of aortic dissection 1. The stent-type artificial blood vessel 2 includes a Gianturco Z-shaped stent 3a and a cloth tubular body 3b surrounding the stent 3a.

FIG. 4 shows the aortic dissection 1, the dissected cavity, the true lumen, the intima pressed from the outside due to the dissection, the stent-type artificial blood vessel 2, and the sheath 4 generated in the arch aorta. . The true lumen is often narrower than the dissociation lumen. Therefore, the rigid true thick sheath into which the rigid and inflexible stent is inserted is curved into the narrow true lumen, as shown in FIG. Inserting along is a very difficult technique. In practice, it can be said that such an ideal insertion is not possible.

(Conventional Type Stent) FIG. 5 schematically shows a typical conventional type stent (Gianturco Z-stent). The stent has a hollow cylindrical shape composed entirely of a linear member (stainless steel wire) having a zigzag structure. FIG. 5 (a) is a schematic side view of the stent (a side view of the cylindrical shape; only the front side of the cylindrical zigzag structure is shown), and FIG. 5 (b) is a schematic front view.
(C) shows a schematic side view of the stent as compressed as possible (when inserted into a sheath or the like). FIG.
Referring to (a), this stent 3a has a zigzag shape including a plurality of linear line portions 5a having the same length and a connecting portion (bent portion) 5b connecting the linear line portions 5a to each other. Having. The straight line portion 5a indicates a straight line portion when formed with a linear member. FIG. 5 (c)
As shown in the figure, the bent portions formed by the linear members overlap each other.

A conventional stent-type artificial blood vessel in which an artificial blood vessel (tubular body) is further placed on the stent of FIG. 5 is shown in a schematic perspective view of FIG. FIG. 6 shows Gianturco Z-stent 3a,
A conventional typical stent-type artificial blood vessel 2 comprising a tubular body 3b surrounding the stent-type artificial blood vessel 2 (FIG. 6 (a)) and a thin sheath 4 (for example, made of a transparent vinyl chloride resin) FIG. 6B shows a state of being inserted inside (FIG. 6B).

Referring to FIG. 6, a conventional Gianturco-type stent (William Cook Europe A / S Bjaever-skov, Denmar
k) is covered with a cloth-made tubular body, and as indicated by an arrow A, a sheath 4 is formed.
Fold in and insert. In this figure, four stents are inserted. However, since each stent is hard and bulky, the sheath 4 into which it is inserted must be naturally thickened. In addition, it is difficult to bend other than joints between individual stents (cylindrical bodies). In this figure, the stent-type artificial blood vessel 2 is inserted into the sheath in a folded state as shown by the arrow A direction, and then inserted into the blood vessel as the sheath 4. After being inserted into the blood vessel, the artificial blood vessel 2 is released from the inside of the sheath 4 as shown by the arrow B direction, and the stent 3a disposed therein expands in the blood vessel.

[0034] Artificial vessels for aneurysms used in clinical practice today are inserted mainly through the femoral artery. In other words, at the base of the leg, from the thigh to the abdominal aorta,
It is inserted toward the thoracic aorta. The schematic sectional view of FIG.
A state is shown in which the right femoral artery 5 is incised, and the sheath 4 in which the stent-type artificial blood vessel 2 is inserted in advance therein is being inserted from the incision site 5.

In practice, the stent-type artificial blood vessel 2 used for such insertion has an original thickness of about 20 to 35.
mm (the state shown in FIG. 6 (a)), and a metal stent is incorporated therein. Therefore, even if the entire thickness is folded as small as possible, a tubular body (artificial blood vessel or the like) surrounding the stent can be obtained.
(For example, the state shown in FIG. 6 (b))
m, often about 8 mm. In order to insert the stent-type artificial blood vessel 2 and guide it to the lesion 1 (FIG. 7), a sheath 4 having a thickness of 18 French or 24 French is generally used (18 French is about 6 mm, 2 French).
4 French has a thickness of about 8 mm). The sheath 4 having such a thickness is a considerably thick tubular material to be inserted into a blood vessel. Generally, a catheter or sheath inserted into an artery for angiography or the like is 6 French (that is, about 2 mm in thickness), so 6 mm to 8 mm is quite thick, and particularly difficult to handle in consideration of its flexibility. Becomes Therefore, when the sheath is too thick to insert into the femoral artery, it is often practiced to make an incision in the abdomen to incise the iliac artery, reach the blood vessel, and insert the sheath. ing.

Referring to FIGS. 3 and 4, which are schematic cross-sectional views showing an ideal state of fixation by such a conventional method, when the stent-type artificial blood vessel is fixed to the blood vessel wall, the sheath 4 is temporarily damaged. The stent-shaped artificial blood vessel 2 is released into the blood vessel from the sheath 4 in the healthy vascular cavity of the part (the part beyond the lesion part 1) by being pushed beyond the part 1 to the healthy part ahead. . Here, the stent (expandable member) 3a portion of the artificial blood vessel 2 is pushed out from the lumen to the blood vessel wall, and is fixed by the spring force of the stent 3a itself. That is, since the stent cannot be fixed to a diseased blood vessel such as the aneurysm 1, the sheath 4 is necessarily advanced beyond the lesioned part 1 and further to the central side closer to the heart to reach a healthy part. After the fact is confirmed, it is general to extrude the stent-type artificial blood vessel 2 and expand and fix it in the blood vessel lumen.

In this method, the above-mentioned “thick and hard” sheath 4 is inserted from the femoral artery or iliac artery in a direction reverse to the blood flow (that is, in a retrograde direction), and the position beyond the lesion 1 of the aneurysm is detected. The sheath 4 is also curvedly inserted so that the curve portion follows the curve of the blood vessel cleverly, and the stent-type artificial blood vessel 2 is extended from the sheath 4 at a healthy site to expand it.
Start fixing. Next, the stent-type artificial blood vessel 2 is gradually taken out from the sheath 4 into the aorta, where the artificial blood vessel 2 is pushed and expanded by an expanding member (3a in FIG. 6), and the position of the sheath 4 is further shifted to the peripheral side. Draws out the stent-type artificial blood vessel 2 into the aorta, and repeats the operation of expanding and expanding the artificial blood vessel 2 by the expansion member 3a, and finally inserts the artificial blood vessel 2 to the peripheral side beyond the lesion 1. Fix it. Such an ideal state of fixing is shown in a schematic sectional view of FIG.

However, in practice, it can be said that the ideal state as shown in FIG. 3 is not obtained at all, and as shown in the schematic sectional view of FIG. ), The blood flow collides with the stent-type artificial blood vessel 2, and as a result, a new thrombus 6 (based on the insertion of the stent-type artificial blood vessel 2)
There is a great possibility that it will be possible. When the occurrence of the thrombus 6 is serious, the blood vessel at this site is completely clogged,
"Reoperation" will be inevitable.

As described above, when the conventional stent is elastically pressed and inserted into the tubular sheath, the stent is folded as small as possible, but the folding size is limited to some extent. According to the study of the present inventor, this has been caused by the fact that the connection portions overlap at one place.

That is, in a zigzag type stent in which a plurality of straight portions having the same length are connected by a connecting portion as in the conventional Gianturco Z-stent disclosed in US Pat. No. 4,580,568, The linear portion can be folded small in a finely-packed manner when pressed elastically. However,
According to the study of the present inventor, since a bent linear object folds at the same place at the connection portion, it was not possible to fold it small in a finely packed manner.

Accordingly, US Pat. No. 4,580,568
In a zigzag type stent in which a large number of straight portions are connected by connecting portions as in the conventional type of the Gianturco Z-stent type disclosed in U.S. Pat. It was the size that overlapped, and was decided by this.

Since many lumens in a living body are not in a straight line, a means for inserting a stent that can follow a curved lumen is required. Therefore, when using a conventional stent, it is necessary to make the sheath for inserting the stent as thin as possible.In particular, in order to allow the stent to be inserted smoothly into a bent portion of a strongly curved aortic arch, etc. The sheath needed to be thinner. This requires that the stent be folded as small as possible.
However, according to the study of the present inventor, in a zigzag type stent in which a large number of straight portions having the same length are connected by connecting portions as in the conventional type, the folds of many connecting portions are concentrated at one place. For this reason, it was not possible to fold it to the same size as the linear portion.

(Stent of the Present Invention) The stent of the present invention has a loop shape (usually, a zigzag structure including a plurality of line portions and a connecting portion connecting the line portions to each other).
(Closed loop). The plurality of line parts include at least one set of line parts adjacent to each other and having different lengths.

FIG. 9 is a schematic sectional view showing one basic embodiment of the stent of the present invention. Referring to FIG. 9, in this embodiment, stent 10 of the present invention has a zigzag structure in which a plurality of line portions (in FIG. 9, non-linear shapes) 11 a and 11 b are connected to each other by connection portion 12. Consisting of a loop-shaped linear member, and the plurality of line portions are
It includes at least one pair of line portions 11a and 11b adjacent to each other and having different lengths. The connection portion 12 shows the “roundness” of the bent portion when the connection portion 12 is made of a linear member.

The stent 10 has a hollow cylindrical shape entirely composed of the zigzag structure. FIG. 9A is a schematic side view of the stent 10 (only a portion near the hollow cylindrical shape is shown), FIG. 9B is a schematic front view, and FIG.
Shows a schematic side view of the stent 10 as compressed as possible (when inserted into a sheath or the like). FIG. 9 (c)
As shown in (1), the bent portions formed by the linear members do not overlap.

(Line portion) In the present invention, it is sufficient that the loop having the zigzag structure includes at least one pair of line portions 11a and 11b which are adjacent to each other and have different lengths. In other words, of the plurality of line portions constituting the zigzag structure, the pair of line portions 11a and 11b
The length and shape of the other parts are arbitrary. From the viewpoint of compactness (thinness) when the compressed state is as high as possible as shown in FIG. 9C, the number of adjacent line portions having different lengths is preferably as large as possible. ), It is most preferable that the line portions have different lengths when viewed from the side.

In the stent 10 according to the present invention, all or a part of the line portions constituting the zigzag structure may be linear, but from the viewpoint of followability to the bent portion in the lumen, The line portion is preferably non-linear (for example, curved).

As described above, in the stent 10 according to the present invention, since the lengths of the line portions 11a and 11b adjacent to each other are different, when the stent 10 is inserted into the bent portion in the lumen, the end of the line portion is The extent to which the adjacent “mountain-shaped” portion of the stent including the connection portion and the other mountain “butt” -shaped portion can be substantially reduced. Therefore, when the stent of the present invention is used, it becomes easy for the stent to easily follow the shape of the bent portion in the lumen.

When the line portion includes a combination of two or more line portions having different lengths, the ratio of the length of the shortest line portion to the length of the longest line portion is preferably 1.1 to 5. .

As described above, in the present invention, the position of the connection portion 12 is changed by changing the length of the line portions 11a and 11b constituting the zigzag structure. That is, there is an advantage that the positions of the connection portions 12 are dispersed when the connection portions 12 are folded as shown in FIG.

No. 4,580,568.
In a conventional type such as a Gianturco Z-stent type stent (FIG. 5 (a)), a zigzag type stent in which a large number of straight portions are connected by a connecting portion, so that a large number of connecting portions 5b are folded at the time of folding. Since the fold overlaps are concentrated at one place (FIG. 5C), it is impossible to fold the small size to the same size as the linear portion. On the other hand, in the stent of the present invention (FIG. 9A), since the positions of the connection portions 12 are dispersed, the connection portions do not overlap at one position, and therefore the entire stent is folded small (FIG. 9A). (C)) becomes possible.

As a result, in the present invention, the sheath for inserting the stent can be smaller in size than the sheath for inserting the conventional stent, and as a result, the sheath itself can be used. This also increases the flexibility, and from this aspect, it is also possible to insert it safely into a curved body lumen.

A further advantage of the variable length line section of the present invention is that the hollow cylinder formed when the stent is in the expanded state is disclosed in US Pat. No. 4,580,568. The disclosed Gianturco Z-stent type stent had a cylindrical shape and a rectangular shape when viewed from the side (FIG. 5C), whereas the present invention has a different line portion length (FIG. 5C). 9 (c)), it is also possible to create a cylindrical state which is curved in the folded state (in FIG. 9 (c), both ends of the cylindrical body are bent downward in the drawing). By observing the curved cylindrical stent 10 from the side, it is possible to form a shape in which an automobile tire is partially cut out toward the center of the ring.

By making the length of the line portion vary (FIG. 9 (a)) in this manner, in a body lumen, a curved portion, such as a strongly bent portion such as an aortic arch, can be formed. In addition, it is possible to prepare a stent that can follow the curve of the wall. Such is the case with the GianturcoZ-s disclosed in U.S. Pat. No. 4,580,568.
This was not possible with a tent type conventional stent.

(Connecting Portion) In the present invention, the shape, material, size, etc. of the connecting portion 12 are determined as long as the connecting portion 12 can exhibit the function of connecting the plurality of line portions 11a and 11b to each other. , Is not particularly limited.

In each stent, the connection 12
Can be designed in such a shape that it does not protrude outside the hollow cylindrical body composed of the line portion.
Further, in the case where the distal end of the connecting portion may protrude due to the strong curve of the body lumen, the protruding portion may be bent by bending the distal end portions of the plurality of connecting portions toward the lumen of the hollow cylindrical body of the stent. Can be prevented. With such a device, it is possible to more strictly avoid partial compression of the wall of the body lumen that is complicatedly curved at any site. As a result, further security is ensured for a long period.

(Connected Body) In the schematic perspective view of FIG. 10, four stents 10 of the present invention described above and a tubular body 13 (for example,
2 shows a state (ie, one embodiment of the stent-type artificial lumen 14 of the invention).

FIG. 11 is a schematic perspective view showing a state in which the stent-type artificial lumen 14 shown in FIG. 10 is curved or bent in accordance with the bent portion of the lumen. From FIG. 11, it can be easily understood that the stent-type artificial lumen 14 of the present invention can sufficiently follow the bent portion of the body lumen.

By connecting a plurality of cylindrical stents such as beer barrels, the body lumen into which the stents are inserted may have a bellows shape, but the lumen area and the degree of non-linearity of the line portion are reduced. In comparison, since the bellows form is weakly deformed, it is considered that there is substantially no adverse effect on the function of the lumen of the body, such as air flow in the trachea or blood flow in blood vessels.

On the other hand, the conventional Gianturco Z-sten
FIG. 3 shows a state in which a zigzag-type stent in which a large number of linear portions are connected by connecting portions, such as a t-type stent, is arranged at a bent portion of a body lumen. As shown in FIG. 3, in a part of the body lumen that is not in a straight state, the connection part located at the end of the straight part may come into contact with the curved body wall in a protruding state. When such a phenomenon occurs, there is a high possibility that the body lumen wall of the relevant portion is damaged.

(Materials of Stent, etc.) As long as the stent 10 having the above structure can be formed, the characteristics, materials, thickness, etc. of the linear members constituting the stent are not particularly limited, and may be appropriately selected from known materials. It is possible to use it.
Usually, the material constituting the stent is often made of a metal (used to include an alloy), but is not limited thereto.

The hollow cylinder may have a circular or substantially circular cross-sectional shape, and if necessary, other than a circular shape selected from H, I, J, and L shapes. It may have a cross-sectional shape.

As the linear member, a monofilament metal wire having a circular cross section, which is used in the prior art, may be used. By forming a multifilament, the strength and flexibility of the linear member may be improved. May be increased.

Further, if necessary, the linear member may have any of known shapes / structures such as a monofilament, a multifilament, and a tape (or a combination of two or more of these structures). it can. This makes it possible to select and adjust the flexibility, restoring force, and the like of the linear member, and facilitate the production of a stent having a curved surface that conforms to the curved surface of the inner surface of a soft lumen (eg, blood vessel) wall.

In forming a stent having a zigzag structure, the present inventors have found that in the present invention, if the line portion is shortened, the spring function by the zigzag may be hardened. In order to cope with this, in the present invention, when forming line portions having different lengths, if necessary, in a portion where the line portion is short, for example, a flexible material is used and / or the wire diameter is reduced. For example, the linear member may have more flexible physical properties than other parts. In this case, the linear member is configured by joining two or more types of materials having different physical properties.

When a stent is inserted into a lumen, it is easy to take a desired shape at a predetermined temperature.
Part or all of the linear member is preferably made of a material having a shape memory function (for example, a shape memory alloy) or a superelastic material (for example, a superelastic alloy). When the shape memory or superelastic function is used as described above, the stent 10
After being folded and inserted into the sheath, when released from the sheath, the hollow cylindrical stent expands in the radial direction based on its superelasticity or shape memory function, and easily returns to its original shape. can do.

As described above, the linear member preferably has a shape memory function or a super elastic function. By providing such a property to the linear member, the stent easily returns to the hollow cylindrical body when released from the sheath, and contributes more effectively to expand the body lumen from the lumen. Becomes possible.

As a material constituting the linear member, more specifically, for example, stainless steel, cobalt chromium,
A metal wire selected from the group consisting of a platinum tungsten alloy and a nickel titanium alloy is exemplified.

(Size) The size of the stent 10 is not particularly limited as long as it can be inserted into the body lumen.

(Manufacturing Method) The manufacturing method of the stent 10 of the present invention is not particularly limited as long as the above-described predetermined shape can be provided, and may be appropriately selected from known material (metal or the like) processing methods. (If necessary, two or more kinds can be used in combination.)

For example, a linear member 21 as shown in the schematic perspective view of FIG. 12 is prepared, and suitable means (for example, a very small hollow tubular connecting means having an inner diameter corresponding to the thickness of the linear member 21) is prepared. 22), the entire linear member 21 may be formed into a hollow cylindrical shape (for example, a beer barrel shape) while connecting both ends 21a and 21b of the linear member 21 to each other.

From the viewpoint of facilitating insertion into a thin (that is, minimizing the effect on the living body) sheath, by folding the hollow cylindrical body, it is possible to reduce the diameter of the hollow cylindrical body to 1/3 or less ( Further, it is preferable that it can be inserted into a sheath having an inner diameter of １ ／ or less.

In order to prevent the connection portion located at the tip of the long line portion from projecting, the tips of two or more of the connection portions 12 of the connection portions 12 are placed inside the hollow cylindrical body. It is preferable to have a structure that is suitable for use.

(Connected Body) The hollow cylindrical stent 10
May be used alone or, if necessary, two or more may be linked. When connecting two or more, the stent 1
It suffices that at least one connection point between 0s is provided. As the number of connections increases, the connection becomes stronger, but the "flexibility" of the stent connection tends to decrease. Therefore, the actual number of connection points may be appropriately determined in consideration of these balances.
About 8 places (more preferably about 2 to 4 places) are preferable.

In this linked stent body, two or more hollow cylindrical stents 10 may be connected so that their longest line portions are in contact with each other, and if necessary, the longest line portions may be connected to each other. Two or more longest line portions may be connected so as not to contact each other (that is, so that the longest line portions form a certain angle). By “shifting” as in the latter, it becomes possible to improve the adaptability to the curved portion of the body lumen.

By connecting a plurality of curved cylindrical stents each having a small radius of curvature such that the longest line portions thereof are aligned with each other, it is possible to cope with even stronger curved portions.

A twisted shape can be obtained by connecting a plurality of curved cylindrical stents having a large radius of curvature so that the longest line portions are not aligned. Accordingly, it becomes possible to cope with a torsionally added body lumen curve portion in this manner.

When the radius of curvature of the curved cylindrical shape is increased, the shape becomes optimal as a stent used for a portion having a gentle curve in the body lumen. As described above, in the present invention, by changing the length of the line portion, it is possible to accurately produce various types of stents according to the shape of the body lumen.

By combining the stents of the present invention having various radii of curvature in such a manner, it is possible to prepare a suitable stent which can be used in many parts of a body lumen having a complicated long curve. it can.

It is possible that the spiral stent disclosed in US Pat. No. 5,800,456 can cope with such a weak curve. However, in the present invention, it is possible to connect short stents one after another according to the length and curve of the body lumen.
The stent can be made much more flexible than the spiral stent disclosed in U.S. Pat. No. 0,456.

As a method of expanding the stent, any of a self-expanding type and a type expanded by another device such as a balloon can be used.

(Tubular Body) The artificial lumen 14 of the present invention can be obtained by arranging the stent of the present invention having the above-described structure in a tubular body 13 as shown in FIG. 10, for example.

The material and form of the tubular body 13 are not particularly limited. From the viewpoint of compatibility with living organisms, it is preferable that the material be made of any of polyester and stretchable polytetrafluoroethylene.

It is preferable that the tubular body 13 is made of a flexible material / form from the viewpoint that the tubular body 13 can be easily bent following a lumen such as a bent blood vessel. For example, when the tubular body 13 is made of a cloth or a film, it is preferable to impart flexibility to these materials by performing bellows or crimping. For example,
When the tubular body 13 is made of a fibrous material (e.g., e-PTFE), it is preferable that the fibril length is appropriately set to impart flexibility. Here, "e-PTFE"
The term "expanded polytetrafluoroethylene", that is, (a polytetrafluoroethylene (Teflon) tube which is made to have a porous state by forming an infinite number of cracks by abruptly stretching the tube and further having flexibility. This e- PT
As the FE, for example, one generally sold under the product name of “Gore-Tex” (Gore, USA) can be used.

When the tubular body 13 is made of cloth, from the viewpoint of the balance between its mechanical strength and flexibility at the time of folding, it is 0.8 denier or less (further, 0.6 denier or less,
In particular, it is preferable to be composed of ultrafine fibers of 0.4 denier or less). The content of the ultrafine fibers is preferably 50 parts or more (more preferably about 60 to 100 parts, particularly about 80 to 100 parts) when the weight of the entire tubular body 13 is 100 parts.

The tubular body 13 covering the outside of the stent 10 is
Usually, it comes into direct contact with the inner surface of the body lumen. When the tubular body 13 is made of a porous material in the present invention, it becomes easy for living cells to enter the porous body,
The integration between the tubular body 13 and the living body is facilitated.

Further, when a "brushed structure" is provided to the tubular body 13, more cells can enter the gaps of the brushed structure, so that the tubular body and the living body can be more smoothly integrated. Becomes Such integration of the tubular body with the living body can contribute to stabilization of the tubular body 13 in the living body for a long time, prevention of unexpected movement of the tubular body 13 in the lumen, and the like.

A known material can be used for the tubular body 13 without any particular limitation. Furthermore, by performing the hydrophilic treatment on the tubular body 13, the adhesion of the thrombus is minimized immediately after the tubular body 13 is inserted into the lumen, and the invasion of the cells of the living tissue thereafter is further promoted.

In the stent-type artificial lumen of the present invention,
Usually, the outside of the stent 10 is covered with the tubular body 13, but on the contrary, the tubular body 13 can be stretched inside the stent 10. In such a case, the stent 10 may be on the outside and directly in contact with the lumen of the living body, and after a long time, the stent may dig into the tissue. In particular, the tendency of a self-expanding stent becomes stronger because the tissue continues to be pressed for a long time.

In the case of a balloon-expandable stent, such a tendency of “tissue compression” is small. On the other hand, in the case of a self-expanding stent, it is preferable that the tubular body 13 be covered on the outside of the stent from the viewpoint of safety.
Even in this case, it is possible to further arrange the second tubular body outside the stent 10 arranged outside the first tubular body. By arranging the tubular body inside and outside the stent in this manner, further integration of the stent and the tubular body is facilitated.

(Method of Use) FIG. 1 is a schematic sectional view of FIG.
0 shows a state in which the artificial lumen 14 of the present invention having the configuration of No. 0 is further disposed inside the sheath 15. Stent 1 of the present invention
In FIG. 13, as shown in FIG. 13, since the connecting portions 12 constituting the stent 10 can be made small so as not to “overlap” with each other, the thickness of the artificial lumen 13 when placed in the sheath 15 is reduced. It is easy to make it thin. Compared to a state in which a conventional Gianturco Z-type stent is similarly made smaller (FIG. 5C), the stent 1 of the present invention
It can be easily understood that 0 can be reduced.

In FIG. 13, the stent 10 is arranged in the same direction in the sheath 15 (that is, the longest line portion is almost straight in the sheath 15). Multiple stents 1
0 shifts the angle little by little (ie, the longest line section spirals within the sheath 15)
It may be arranged. The “shift” angle in this case is 180
Any angle, such as °, 90 °, 45 °, etc., can be taken.

Since the stent of the embodiment shown in FIG. 9 of the present invention has two lengths different from each other, it should be "outside" and "inside" when it is arranged at the bent portion. Side and exists.

After the member is placed in the lumen and the expansion member is expanded, these differences can be confirmed by directly checking the expanded zigzag shape by X-rays or the like. In FIG. 13), it is not always easy to check the outside and inside. Therefore, from the viewpoint that the outside and the inside of the stent of the present invention can be clearly distinguished even in the sheath, it is preferable to provide a marker that can be identified under fluoroscopy to the stent. For example, a long marker may be provided on a side having a long line portion, and a short marker may be provided on a side having a short line portion.

The method for providing such a marker is not particularly limited. That is, known methods (eg, US Pat. No. 5,824,042 and US Pat.
7,442) can be used.

In such a stent having a different length of the line portion, the directionality at the time of insertion becomes a problem, and it is extremely difficult for the stent to be inserted and expanded properly in a position corresponding to a curve in a body lumen. preferable. From the viewpoint of facilitating confirmation of the correct direction of the insertion of the stent, as described above, the portion having the longest length of the line portion of the stent and the portion having the shortest length are each X-ray transparent. It is preferable to attach a marker that can be identified below.

(Surface Treatment of Stent) In the present invention, before the stent 10 is inserted into the body lumen, the stent may be subjected to a surface treatment, if necessary.
The surface treatment of such a stent 10 or a linear member constituting the stent 10 includes antithrombotic, biocompatible, hydrophilic,
1 selected from hydrophobicity, lipophilicity, water content, lubricity, etc.
Surface treatments that should impart more than one or more properties are included.

(Outer Projection) As shown in the schematic perspective view of FIG. 14, the stent 10 of the present invention is provided with a small projection (stab) toward the outside of the stent, if necessary. Is also good. By providing such a protrusion, the stent 1 of the tubular body 13 to be covered around the stent 10 is formed.
It is easier to prevent a “shift” from zero.

The “height” of the projection is made larger (longer)
In this case, the projection may penetrate the tubular body 13 and reach the wall of the body lumen. The protrusion penetrating the wall of the body lumen also makes it possible to prevent unexpected movement of the stent 10 with respect to the body lumen. On the other hand, the effect of ensuring the "fixation" of the projection to the wall of the body lumen is not expected to be as great as the effect of "preventing slippage".

(Arrangement in Lumen) Stent 10 of the Present Invention
In addition, the stent-type artificial lumen 14 can be inserted and arranged in a body lumen in the same manner as a conventional stent or artificial blood vessel.

For example, after the stent-type artificial lumen 14 of the present invention having the configuration of FIG. 10 is placed in the sheath 15 as shown in FIG. 13, the abdominal aorta is removed from the femoral artery in the same manner as in FIG. Then, it may be inserted toward the thoracic aorta.

When the artificial lumen 14 reaches the curved portion of the lumen, as shown in FIG. 11, the stent 10 constituting the artificial lumen 14 is expanded according to the curve of the living body lumen. Therefore, the artificial lumen 14 can be more easily fitted to the curve of the living body lumen.

In FIG. 10, the stent is designed so that the line portions are curved and the lengths of the individual line portions are different.
0 shows a state in which the tubular body 13 is put on and expanded to make a straight line state. In this embodiment, the tubular body 13 that covers the outside of the stent 10 has a bellows structure, but is not recognized in this figure because the bellows structure is fully extended on one side. Very little is observed because it is also growing on the other side. Therefore, even if the tubular body is folded and inserted into the sheath in such a state, the bellows structure of the tubular body does not suffer. FIG. 11 shows a state where this is bent. The bellows structure on the large bay side is still stretched, but the bellows structure appears on the small bay side due to bending. In this state, since the sheath has already exited the body lumen, a bellows structure may appear, which helps prevent kink and does not significantly affect the movement of fluid in the lumen.

FIG. 15 shows a stent 10 of the present invention (FIG. 1).
1 shows a state in which a conventional cylindrical stent 20 (for example, a Gianturco Z-type stent) is added before and after the connection portion so as to correspond to the straight portion before and after the connection portion.

In this case, a stent according to a second aspect of the present invention described later, that is, a stent in which the individual lengths of the non-linear line portions are equal, ie, a zigzag structure having an “outwardly bulging” shape like a beer barrel May be used instead of the conventional stent 20.

(Modification) The stent of the present invention suffices if it has at least one set of adjacent line portions having different lengths among a plurality of line portions constituting the stent. Therefore, a plurality of line portions having different lengths are respectively represented by A, B, C, D, E, F, G (where A>B>C> D
>E>F> G), the following variations are possible.

ABC-ABC-ABC... ABCD-ABC-ABC... ABCD-ABCDE-ABCDE... AA-BB -AA: AA-BB-CC-AA-BB-CC ... ACDDEFG (as shown in FIG. 9A; (Second Aspect) In the above description, mainly the first aspect of the present invention (the stent 10 includes at least one set of line portions which are adjacent to each other and have different lengths) has been described. In the stent of the present invention, the stent comprises a loop-shaped linear member having a zigzag structure including a plurality of line portions and a connection portion connecting the line portions to each other, and the plurality of line portions are non-linear. The line part of It may be included in the part.

FIG. 16 shows an example of such a stent according to the second embodiment.

FIG. 16 (a) is a schematic side view of the stent (only the front part of the zigzag structure cylinder is shown), and FIG.
(B) shows a schematic front view. Referring to FIG.
The stent 24 has a zigzag shape including a plurality of non-linear (curved in this figure) line portions 25a having the same length and connecting portions 25b connecting the non-linear line portions 25a to each other.

When the non-linear line portion 25a is curved, the radius of curvature of the curve is 3 to 50 cm, and more preferably 4 to 2 cm.
It is preferably in the range of 0 cm (particularly 5 to 15 cm).

The non-linear line portion 25a is 3 to 4
It is preferably a polygonal line having one or more refraction sites at an angle of 5 °, more preferably 5 to 30 ° (particularly 10 to 25 °).

When the stent 24 of the present invention having the above-described configuration (second embodiment) is inserted into a body lumen, the above-described non-linear portion 25a of the line portion (compared to the linear portion)
Since the stent 24 fits well into the shape of the bent portion of the body lumen, it becomes easy for the stent 24 to easily follow the shape of the bent portion of the body lumen.

When the individual line portions are non-linear as described above, in order to reduce the degree of local “compression” on the body lumen wall as much as possible, the distal end of each connection portion is connected to the stent lumen. It is preferable to have a shape directed to the side. In this case, the whole image of the stent shows a form like a beer barrel.

As described above, the stent of the present invention (second
Is a stent that takes a shape that sufficiently follows the shape of the curved wall of the body lumen and does not cause abnormal deformation of the wall of the body lumen. Whereas a conventional zigzag stent was composed of straight line portions and connecting portions having the same length, in the present invention, a conventional zigzag stent had the straight portion as a part of the basic structure. By making the portion non-linear, the connecting portion is prevented from protruding from the wall of the body lumen. By such an improvement, the stent follows the curve without damaging the wall of the curved body lumen, and exhibits a reliable fixing function by utilizing its elasticity and the like.

As disclosed in US Pat. No. 4,580,568
In the case of a zigzag type stent in which many straight lines of the same length are connected by a connecting portion like a Gianturco Z-stent type stent, considering that the body lumen is never in a linear state, The located connections may protrude into the body lumen of the curved wall. This phenomenon causes damage to the body lumen wall of the relevant portion. According to the study of the present inventor, one of the causes is that the lines of the same length that form the linear portions constituting the zigzag structure are in a linear state.

In the present invention (second embodiment), at least a part of the zigzag line constituting the stent is in a non-linear state. In the present invention, by forming the non-linear portion as a curved line or a broken line having a bent portion, a state is obtained in which the connecting portion located at the end of the line portion does not protrude from the wall of the body lumen. In addition, by making the line portion non-linear in this way, it is possible to satisfy the conditions required for the stent, such as being able to maintain strong expandability, which is a characteristic of the zigzag structure, and to provide a secure fixing function of the stent. It has been found that it can be demonstrated.

Even when the line portion is in a non-linear state, the small folding property is not substantially lost. According to the study of the present inventor, this is because, in the case of a conventional stent, a curved or bent line portion having a bent portion is almost straightened by compression when folded. It has been found that it is possible to fold small, closely packed like a straight section.

(Other Embodiments) FIGS. 20 to 26 show other embodiments of the stent of the present invention. In both figures,
(A) is a schematic side view (only the front side of the zigzag-structured cylindrical body is shown), and (b) is a schematic front view.

FIG. 20 shows an example in which a line portion of the stent of the present invention is provided with a broken line structure. The length of each line portion changes gradually, and has a shape close to a trapezoid as a whole. There are two refraction points in the broken line portion (the refraction angle is, for example, 25 degrees). (A) is a schematic side view thereof, and (b) is a schematic front view thereof. The ratio between the longest line portion and the shortest line portion is preferably in the range of 1.1 to 5.0.

FIG. 21 shows another example of the stent of the present invention in which the line portion has a broken line structure. The lengths of the individual line portions are the same, so that the overall shape (hollow cylindrical shape) of the stent is shaped like a beer barrel. There are three refraction points in the broken line portion (the refraction angle is, for example, 20 degrees).

FIG. 22 shows an example of the stent of the present invention in which the line portion has a curved structure. The radius of curvature of the line portion of the curved structure is, for example, 25 cm, and the length of each line is the same. Therefore, the entire stent has a shape like a beer barrel. (A) is a schematic side view thereof, and (b) is a schematic front view thereof.

FIG. 23 shows an example of the stent of the present invention in which a plurality of connecting portions 12 have a structure facing the lumen direction of the hollow cylindrical body of the stent. The line portion has a curved structure (the radius of curvature of the line portion is, for example, 45 cm). The length of each line portion changes gradually, and has a shape close to a trapezoid as a whole. Length of longest line (side A
The ratio of B) to the shortest side DC is preferably in the range of 1.1 to 5.0. As shown by A and B in FIG. 23 (a), a structure in which the connection portion between the longest line portion and the bent portion is oriented in the lumen direction of the hollow cylindrical body of the stent is preferable.
The “arrow” in FIG. 23 indicates a connection portion facing the lumen side.

FIG. 24 shows an example of a stent of the present invention having different lengths of line portions.
The line portion has a curved structure (the radius of curvature of the line portion is, for example, 45 cm). There are three types of lengths of the line portion, which gradually become shorter and have a shape close to a trapezoid as a whole. The ratio between the length of the longest line portion (side AB) and the shortest side DC is preferably in the range of 1.1 to 5.0.

Hereinafter, the present invention will be described more specifically with reference to examples.

[0125]

EXAMPLES Production Example 1 Using a device (circulation model) whose schematic cross-sectional view is shown in FIG. 17, the stent of the present invention and a stent-type artificial lumen were evaluated. In the apparatus shown in FIG. 17, models of blood vessels from the ascending aorta to the aortic arch, the descending aorta, the abdominal aorta, the left and right iliac arteries, and the left and right femoral arteries were created.

The apparatus shown in FIG. 17 is a combination of a model of the aorta and its side branch, a pump for pulsatile heart surgery, and a simulated blood warmer attached to flow simulated blood to the model. Is disclosed in U.S. Pat.
No. 771, etc.). Here, as the simulated blood, for example, blood having the same viscosity as blood by mixing polyethylene glycol, or physiological saline can be used.

More specifically, the device of FIG. 17 uses the light transmissive (tran) disclosed in US Pat. No. 4,655,771.
sluminal) A model of the aorta and its side branch prepared with reference to the prosthesis for transplantation, and a combination of a pulsatile surgical heart pump 24 and a simulated blood warmer 25 attached for flowing simulated blood through the model Device. Arrow 26 indicates the direction of the simulated blood flow. In FIG. 17, the names of the parts corresponding to arteries are represented by the numbers of the respective parts shown below,
The mutual positional relationship is displayed.

27: ascending aorta, 28: brachiocephalic, 29: left common carotid, 30: left subclavian, 31: thoracic descending, 32: right renal artery Reference numeral 33: left renal artery equivalent part, 34: abdominal aorta equivalent part, 35: right common iliac artery equivalent part, 36: left common iliac artery equivalent part, 37: right external iliac artery equivalent part, 38: left outside Iliac artery equivalent part, 39: right internal iliac artery equivalent part, 40: left internal iliac artery equivalent part, 41: right femoral artery equivalent part, 42: left femoral artery equivalent part.

The size of each part of the actual circulation model (FIG. 17) is approximately similar to the size of an adult blood vessel. For example, the inner diameter of the ascending thoracic aorta is 30 mm, the descending thoracic aorta is 25 mm, the abdominal aorta is 18 mm, The bone artery was made to have an inner diameter of 10 mm.

Next, a simulation is performed in which an artificial lumen is inserted from the right femoral artery on the assumption that an aortic dissection 60 having an entry about 2 cm distal to the arch aortic bifurcation of the left clavicular artery has occurred in the thoracic aortic arch. Experiment in vit
I went with ro. At this time, the thickness of the distal side of the aortic arch was 2.8 cm in inner diameter, and the right femoral artery was 1.0 cm.

Example 1 Two types of artificial lumens having the shape shown in FIG. 9 were made of a superelastic stainless steel wire and a polyester cloth.

One stent (corresponding to the first embodiment of the present invention) has a curved cylindrical shape, and its size is a curved state in which the non-linear line portions 11a and 11b have a radius of curvature of 12 cm. Long non-linear line portion 11a
Is 3 cm, the length of the shortest non-linear line portion 11c is 1.5 cm, and the lengths of the other non-linear line portions are sequentially reduced from 3 cm to 1.5 cm. Designed. This stent is 4.0 cm in diameter when expanded.
Could be extended to

The other stent (corresponding to the second embodiment of the present invention) is a beer barrel-shaped stent, the size of which is such that the non-linear line portion 11a has a curvature having a radius of curvature of 12 cm. Have the same length.

Referring to FIG. 10, two of the former (first embodiment) and one of the latter (second embodiment) are connected by a curved line (the connection points between the stents are two places). The tubular body 13 that covers the outside of is made of a plain woven polyester cloth having a thickness of 0.2 mm, and is subjected to shallow and gentle bellows processing (the interval between the "peaks" of the bellows is about 2 mm). The inner diameter of the tubular body is 3.2
cm, the three stents and the tubular body were inserted into a sheath (manufactured by Cook) to form the artificial lumen 14. As a result, the artificial lumen 14 could be inserted into a 22 French (about 7 mm diameter) sheath. Was.

The artificial lumen 14 obtained as described above was led by a guide wire (not shown; diameter: 1 mm, manufactured by Cook), and a sheath from the right femoral artery (corresponding to) as shown in FIG. When inserted into the aortic arch and pushed out with a pusher rod at this point, the aortic arch was curved from the bifurcation of the left clavicular artery to the descending aorta via the aortic arch. It was possible to place the artificial lumen in this state.

At this time, while confirming the direction of the stent under X-ray observation, the stent was pushed out in a direction in which the greater curvature side of the curved stent coincided with the greater curvature side of the aortic arch. It was easy to confirm the directionality with an X-ray because the longest non-linear line portion and the shortest portion were marked with a radiopaque material (titanium compound) in advance.

Example 2 The same experiment as in Example 1 was performed, except that the shape of the stent was changed.

In this example, three stents were connected in the same manner as in Example 1. Of the three stents,
As the two curved stents, the non-linear line portion of the stent as shown in FIG. 20 is a broken line having three bent portions at an angle of about 20 degrees, and the longest non-linear line portion is 3 cm. , The shortest part is 1.5cm
The length of the other non-linear line portions was designed to be gradually reduced from 3 cm to 1.5 cm. This stent was expandable to 4.0 cm when expanded.

The other stent is a beer barrel-shaped stent as shown in FIG. 21. The size of the stent is a broken line in which three non-linear line portions are bent at approximately 10 degrees at three positions. Has the same length as the non-linear line portion.

Two formers and one latter were connected in the same manner as in Example 1, and the tubular body covered on the outside was 0.2 mm thick.
With a shallow and gentle bellows processing using a polyester plain woven cloth. The inner diameter of the tubular body was 3.2 cm, and when the three created stents and the tubular body were inserted into the sheath,
It could be inserted into a 22 French sheath.

In the same manner as in Example 1, the artificial lumen thus created was guided in vitro with a guide wire, inserted into the aorta of the bow together with the sheath, and extruded with a pusher rod at this point. When a simulation experiment was performed on the aortic arch from the bifurcation of the left clavicular artery to the descending aorta via the arch aorta, good results similar to those obtained in Example 1 were obtained. .

Comparative Example As a control experiment, an experiment using a conventional Gianturco Z-stent was performed, assuming that aortic dissection occurred in the same place. As the stent, three Z-stents manufactured by Cook, and a size of 40 mm when expanded were connected. One stent was 2.5 cm long. The outer tubular body was the same as that used in Example 1.

When an attempt was made to insert the sheath into the sheath in this state, it was difficult to insert the sheath, and it was finally possible to insert the sheath into a 24 French sheath. Next, I tried to insert it into the aorta of the bow while guiding it with a guide wire, but it was difficult to enter because the sheath was thick and hard. However, it was inserted to a point slightly beyond the bifurcation of the left clavicular artery about 2 cm from the bifurcation to the central side (see FIG. 19).

Next, the artificial lumen was pushed out into the lumen with the pusher rod, but it was straightly inserted into the curved aorta, and on the central side, part of the artificial lumen was reduced to the artery on the greater curvature side. It hit the part where dissociation was assumed to occur and became biting, and the opposite end was floating in the blood vessel cavity and could not be brought into close contact with the blood vessel wall.

[0145]

According to the present invention, as described above, a loop-shaped linear member having a zigzag structure including a plurality of line portions and a connecting portion connecting the line portions to each other is provided;
In addition, a stent is provided that includes at least one set of line portions in which the plurality of line portions are adjacent to each other and have different lengths.

[0146] According to the present invention, the loop-shaped linear member having a zigzag structure including a plurality of line portions and a connecting portion connecting the line portions to each other; And a stent including at least a portion of a non-linear line portion.

[0147] The stent of the present invention having the above-described structure can be placed following a bent portion of a body lumen based on the presence of line portions (or non-linear line portions) having different lengths, and can be placed in the thoracic aorta. Can be used without difficulty even in a strongly curved part such as the arch aorta.

Further, the stent of the present invention can be easily inserted into a thin sheath because it can be easily folded into a small size.
Therefore, it is easy to bend. Therefore, it is easy to insert it safely and reliably even in a strongly curved portion.

[0149] The stent-type artificial lumen of the present invention, which is a combination of the above-described stent and tubular body, can be easily folded small, so that it is possible to prevent damage to the fibers of the tubular body when passing through the sheath. In the long run, it is possible to provide safe surgical results.

In the stent-type artificial lumen of the present invention, a tubular body can be placed in a bent portion of an artery in a state where the tubular body follows the curve of the wall well, and can be in close contact with the blood vessel wall.
It can minimize abnormal turbulence generated in blood vessels and prevent excessive thrombus formation.

In the stent-type artificial lumen of the present invention, a tubular body can be placed in a bent portion of an artery while following a curve of the wall, and can be brought into close contact with a blood vessel wall. In the treatment of a disease such as aortic dissection, which has entered, blood leakage can be accurately prevented, so that the effect is remarkable.

Even in the case where the degree of the curve varies depending on the individual patient, such as the aortic arch, since a stent that follows the curve can be prepared, a safe treatment can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing names of main arteries placed in a human arterial system.

FIG. 2 is a schematic cross-sectional view showing an example in which a part of a blood vessel wall at a curved part of an arch aorta is damaged to cause aortic dissection 1, thereby causing an aortic aneurysm (dissecting aortic aneurysm).

FIG. 3 is a schematic cross-sectional view showing an ideal state when a conventional stent-type artificial blood vessel including the lesioned part 1 is inserted and fixed on the central side and the peripheral side thereof.

FIG. 4 is a schematic cross-sectional view showing an ideal state when a conventional stent-type artificial blood vessel is fixed to a blood vessel wall. A sheath into which a conventional stent-type artificial blood vessel is inserted is inserted to the central portion side beyond the lesion 1, and at this site, the stent-type artificial blood vessel is extruded from the sheath.

FIG. 5 shows a typical conventional stent (Gianturco Z-
It is a schematic diagram which shows a stent) typically. FIG. 5A is a schematic side view of the stent (only a portion on the near side is shown), FIG.
(B) shows a schematic front view, and FIG. 5 (c) shows the stent as compressed as possible.

FIG. 6 is a schematic perspective view showing a conventional typical stent-type artificial blood vessel and a sheath.

FIG. 7 is a schematic cross-sectional view showing a state in which a right femoral artery 5 is incised, and a sheath 4 in which a conventional stent-type artificial blood vessel 3 is inserted in advance therein is being inserted from the incision site.

FIG. 8 is a schematic cross-sectional view showing a state in which a new thrombus 6 has been formed at the site as a result of the collision of the blood flow with the stent 3a.

FIG. 9 is a schematic view showing one basic embodiment of the stent of the present invention. FIG. 9A is a schematic side view of the stent 10 (only a portion on the near side), FIG. 9B is a schematic front view, and FIG.
(C) shows a schematic side view in the state of being compressed as much as possible. An example having a shape close to a trapezoid in a side view thereof is shown. The line portion has a curved structure (the radius of curvature is, for example, 45 cm) and is made of, for example, a superelastic linear body. The ratio between the long side and the short side of the trapezoid is, for example, in the range of 1.1 to 5.0.

10 is a schematic perspective view showing one embodiment of a stent-type artificial lumen of the present invention in which four stents of FIG. 9 are connected in succession and the outside of which is covered with a tubular body (the stent is expanded). Status). Although the tubular body has a bellows structure, since it is extended, the bellows structure has practically disappeared, and a little bellows is seen on the side corresponding to the bay side. In this state, the bellows structure does not hinder the folding because it is folded and inserted into the sheath.

FIG. 11 is a schematic perspective view showing a state in which the stent-type artificial lumen of FIG. 10 is bent. Since the Great Bay is extended, the bellows structure has practically disappeared, and the bellows can be seen on the small bay side. In the expanded state, the bellows structure has already come out of the body lumen, so that the bellows structure may come out. This bellows prevents kink of the tubular body.

FIG. 12 is a schematic plan view showing a state where the stent of the present invention shown in FIG. 9 is deployed.

FIG. 13 is a schematic cross-sectional view showing a state where the stent-type artificial lumen of FIG.

FIG. 14 is a schematic perspective view showing an example of a stent of the present invention in which a protruding portion directed to the outside of a hollow cylindrical body made of a zigzag structure is provided. Long, the ratio is 1.1 to 5.0
Range.

FIG. 15 shows the stent of the embodiment of FIG.
It is a schematic perspective view which shows the state which arranged the normal beer barrel-shaped stent.

FIG. 16 is a schematic side view (a) and a schematic front view showing a stent according to a second embodiment of the present invention in which the line portion is non-linear.

FIG. 17 is a schematic cross-sectional view showing a circulation model system of a human blood flow used in Example 1.

FIG. 18 is a schematic view showing a state in which a stent-type artificial lumen of the present invention is inserted together with a sheath from the right femoral artery (corresponding to the same) to the arch aorta in the first femoral artery and pushed out by a pusher rod at this part. It is sectional drawing.

FIG. 19 is a schematic cross-sectional view showing a state in which a conventional stent-type artificial lumen is inserted together with a sheath from a right femoral artery (corresponding to a portion thereof) to a bow aorta in a comparative example, and extruded with a pusher rod at this portion. FIG.

FIG. 20 is a schematic view showing an example of the stent of the present invention in which the line portion has a broken line structure. (A) is a schematic side view thereof, and (b) is a schematic front view thereof.

FIG. 21 is a schematic view showing another example of the stent of the present invention in which the line portion has a broken line structure. (A) is a schematic side view thereof, and (b) is a schematic front view thereof.

FIG. 22 is a schematic view showing an example of the stent of the present invention in which the line portion has a curved structure. (A) is a schematic side view thereof, and (b) is a schematic front view thereof.

FIG. 23 is a schematic view showing an example of the stent of the present invention having a structure in which a plurality of connection portions are oriented in the lumen direction of the hollow cylindrical member. (A) is a schematic side view thereof, and (b) is a schematic front view thereof.

FIG. 24 is a schematic view showing an example of the stent of the present invention having line portions having different types of lengths. (A) is a schematic side view thereof, and (b) is a schematic front view thereof.

Claims (29)

[Claims] 1. A loop-shaped linear member having a zigzag structure including a plurality of line portions and a connection portion connecting the line portions to each other; and the plurality of line portions are adjacent to each other and have a long length. Claims 1. A stent comprising at least one set of line sections that differ. 2. The stent according to claim 1, wherein the plurality of line portions include at least a portion of a non-linear line portion. 3. A loop-shaped linear member having a zigzag structure including a plurality of line portions and a connecting portion connecting the line portions to each other; and wherein the plurality of line portions are non-linear lines. A stent comprising at least a portion. 4. The stent of claim 3, wherein the plurality of line portions include at least one set of line portions that are adjacent to each other and have different lengths. 5. The stent according to claim 2, wherein the non-linear line portion is curved, and a radius of curvature of the curved line is in a range of 3 to 50 cm. 6. The stent according to claim 2, wherein the non-linear line portion is a polygonal line shape having at least one refraction portion at an angle of 3 to 45 °. 7. The non-linear line portion includes a combination of two or more types of line portions having different lengths, and the ratio of the length of the shortest line portion to the length of the longest line portion is 1.1.
The stent according to any one of claims 1 to 6, wherein 8. The method according to claim 1, wherein the whole has a hollow cylindrical shape.
8. The stent according to any one of items 7 to 7. 9. The stent according to claim 8, wherein two or more of the connection portions have a structure in which the tips of two or more connection portions face the inside of the hollow cylindrical body. 10. The stent according to claim 1, wherein the linear member is made of a material having a shape memory and / or a superelastic function. 11. The stent according to claim 1, wherein the linear member is a single metal wire selected from the group consisting of stainless steel, cobalt chromium, platinum tungsten alloy, and nickel titanium alloy. 12. The stent according to claim 1, wherein the linear member is made of two or more materials having different physical properties. 13. The stent according to claim 1, wherein the linear member has a circular or substantially circular cross-sectional shape. 14. An H-shaped, I-shaped, J-shaped linear member.
The stent according to any one of claims 1 to 12, having a cross-sectional shape other than a circle selected from a letter shape and an L shape. 15. The stent according to claim 1, wherein the linear member is surface-treated. 16. The stent according to claim 1, wherein the linear member has at least a part of a marker that can be identified by fluoroscopy. 17. The stent according to claim 8, wherein at least a part of the linear member is provided with a protruding portion directed toward the outside of the hollow cylindrical body. 18. The stent according to claim 8, wherein the stent can be inserted into a sheath having an inner diameter of 1/3 or less of the diameter of the hollow cylindrical body by folding. 19. After being folded and inserted into a sheath, when released from the sheath, it expands in the radial direction of the hollow cylindrical body based on the elasticity or shape memory function of the linear member, and returns to its original shape. 20. The method according to claim 19, further comprising the steps of:
The stent according to any one of the above. 20. The stent according to claim 8, wherein two or more hollow cylinders are connected. 21. The stent according to claim 20, wherein two or more of the hollow cylindrical bodies are connected so that their longest line portions do not contact each other. 22. The stent according to claim 20, wherein two or more of the hollow cylindrical bodies are connected so that longest line portions thereof are in contact with each other. 23. An artificial lumen comprising at least the stent according to any one of claims 1 to 22, and a tubular body surrounding the stent. 24. The artificial lumen according to claim 23, wherein said tubular body is made of a porous material. 25. The artificial lumen according to claim 23, wherein the tubular body is crimped. 26. The artificial lumen according to claim 23, wherein the porous tubular body is made of any one of polyester fiber and stretchable polytetrafluoroethylene. 27. The artificial lumen according to any one of claims 24 to 26, wherein at least a part of the porous tubular body is made of ultrafine fibers of 0.8 denier or less. 28. The artificial lumen according to claim 24, wherein at least a part of the porous tubular body has a raised structure. 29. The artificial lumen according to claim 23, wherein the tubular body is subjected to a hydrophilic treatment.