JP6828990B2 - Stent - Google Patents

Description

The present invention relates to a stent that is inserted and placed in an internal lumen such as a blood vessel.

Conventionally, when an abnormality such as stenosis or occlusion occurs in a lumen such as a blood vessel, for example, stent treatment is performed in which a stent is inserted into the stenotic part in the lumen to keep the lumen in an expanded state. .. This stent enables expansion and contraction deformation, and in consideration of reducing the burden on the living body and improving biofusion, for example, as described in Japanese Patent Application Laid-Open No. 2007-267844 (Patent Document 1). A skeletal structure such as a mesh shape or a coil shape is adopted, and many window-shaped gaps that penetrate the peripheral wall portion in and out and open are provided.

By the way, when the tissue forming the stenosis is a soft porridge, the porridge may re-protrude through the gap between the struts forming the skeletal structure of the stent, and restenosis may occur at the indwelling position of the stent. It was. In addition, the porridge that re-protruded to the inner peripheral side of the stent spreads downstream of the stent placement position due to blood flow, and there is a possibility that restenosis may occur downstream of the stent placement position.

Therefore, according to Japanese Patent Application Laid-Open No. 2004-522494 (Patent Document 2), the second stent is delivered to the inside of the first stent previously placed in the blood vessel, and the second stent is further superposed on the inner circumference of the first stent. The technique of re-stenting is disclosed. In this prior art, it is said that porridge that re-protrudes through the gap of the first stent can be suppressed by the second stent that is placed later.

However, in the prior art described in Patent Document 2, since it is necessary to place the second stent in the first stent after a predetermined period of time after the first stent is placed, an operation in which the stent is placed a plurality of times is performed. It was a heavy burden on the patient.

JP-A-2007-267844 Special Table 2004-522494

The present invention has been made in the background of the above circumstances, and the problem to be solved thereof is to effectively prevent restenosis of the internal lumen while avoiding an excessive burden on the patient and the practitioner. It is to provide a stent with a novel structure that can be used.

The first aspect of the present invention is a single structure in which a first skeletal structure provided with a first gap and a second skeletal structure provided with a second gap are integrally formed with each other. The second skeletal structure in the second skeletal structure is made smaller by the first skeletal structure , and the first skeletal structure forms a diamond-shaped opening having a substantially constant size. The cells of the basic structure to be formed have a mesh shape in which the cells have a repeating structure in which they are continuous at constant pitches in the circumferential direction and the axial direction, respectively, while the second skeletal structure has one linear body folded back in the axial direction . However, the stent has a cylindrical coil shape that extends spirally in the circumferential direction, and the first skeletal structure is located and integrated in the intermediate portion in the thickness direction of the second skeletal structure. Is.

According to the stent having a structure according to this embodiment, a composite peripheral wall in which a first skeletal structure having a first gap and a second skeletal structure having a second gap are inseparably integrated with each other. It is a structure. Therefore, for example, the second skeletal structure secures the supporting strength against the peripheral wall of the lumen such as a blood vessel, and the first skeletal structure reduces the second gap, which is effective in re-protruding the plaque after stent placement. It is also possible to suppress it.

In particular, since the stent according to this aspect has a peripheral wall structure in which the first skeletal structure and the second skeletal structure are inseparably integrated with each other, the prior art described in Patent Document 2 As described above, it does not require a plurality of operations such as placing a second stent after placing the first stent, and it is placed in the lumen by one operation. This can surely reduce the burden on the patient and the practitioner. Further, according to the stent having a structure according to this aspect, since the mesh-shaped first skeletal structure is located in the intermediate portion in the thickness direction so as to enter the coil-shaped second skeletal structure, the first Compared with the case where the skeletal structure of 1 and the skeletal structure of the second are overlapped inside and outside, the thickness dimension (diametrical dimension) of the stent can be suppressed to be small. As a result, inhibition of blood flow and the like when the stent is placed in the lumen can be suppressed, and restenosis of the lumen due to adhesion of a thrombus or the like to the inner peripheral surface of the stent can be more effectively prevented.

Further, as the first and second skeletal structures constituting the stent of the present invention, the following aspects can also be adopted.

A second aspect of the present invention is a single structure in which a first skeletal structure provided with a first gap and a second skeletal structure provided with a second gap are integrally formed with each other. The cells of the basic structure in which both the first skeleton structure and the second skeleton structure form a rhombic opening having a substantially constant size are constant in the circumferential direction and the axial direction, respectively. The first skeleton structure and the second skeleton structure having mesh intervals equal to each other are out of phase with each other in a mesh shape having a continuous repeating structure at a pitch . The first skeletal structure in the first skeletal structure is overlapped in the thickness direction of the peripheral wall so that the connecting portion of the rhombic opening in the second skeletal structure is located in the central portion of the rhombic opening in the skeletal structure. The stent is characterized in that the gap 1 is made smaller in the second skeletal structure, and the second gap in the second skeletal structure is made smaller in the first skeletal structure.

A third aspect of the present invention is a single structure in which a first skeletal structure provided with a first gap and a second skeletal structure provided with a second gap are integrally formed with each other. Both the first skeletal structure and the second skeletal structure are formed into a cylindrical coil shape in which one linear body extends radially in the circumferential direction while being folded back in the axial direction. The first skeleton structure and the second skeleton structure are overlapped with each other in the thickness direction of the peripheral wall in a state where the first skeleton structure and the second skeleton structure are displaced from each other. The stent is characterized in that the gap 1 is made smaller in the second skeletal structure, and the second gap in the second skeletal structure is made smaller in the first skeletal structure.

For example, when the second stent is placed after the placement of the first stent as in the conventional structure described in Patent Document 2, the skeletal structures of both stents overlap at the same position, and the gap is not reduced. Although re-protrusion of plaques and restenosis of the lumen may not be prevented, in the stents of the second and third aspects according to the present invention, the same type of mesh-like or coil-like skeletal structure is used in the first and second aspects. Even when it is adopted as a skeletal structure, it is possible to surely reduce the gap and stably obtain the desired effect because it is integrated in advance.

Therefore, according to the stent having a structure according to the second and third aspects, it is possible to adopt the same structure as the first skeletal structure and the second skeletal structure, for example.

Further, according to the stent having a structure according to the second and third aspects, even if the strength of a single skeletal structure is insufficient, not only two of them are stacked but also they are integrated with each other. Therefore, it is possible to efficiently secure strength and rigidity while avoiding an increase in thickness dimension. Moreover, even if the characteristics are difficult to achieve with a mesh-like or coil-like skeletal structure with a small gap, they can be realized by considering the selection of the first skeletal structure and the second skeletal structure and the mutual integration conditions. It becomes possible to secure a large degree of freedom in setting the characteristics of the stent.

Further, according to the stent having a structure according to the second and third aspects, for example, the gap between the first skeletal structure and the second skeletal structure is made smaller than each other, so that the skeletal structure is compounded. The effect of reducing the gap can be achieved more efficiently.

A fourth aspect of the present invention, prior Symbol stent according to a third aspect, the first gap in said first skeletal structure is smaller than the second gap in the second framework structure At the same time, the second skeletal structure is superposed on the outer peripheral side of the first skeletal structure.

According to the stent having a structure according to this aspect, the inner peripheral surface is curved with less unevenness because the axial spacing, that is, the gap in the skeletal structure is smaller on the inner peripheral side than on the outer peripheral side. While it can be a surface, large irregularities can be formed on the outer peripheral surface. As a result, the effect of suppressing the occurrence of thrombus and the like to prevent restenosis of the lumen and the effect of positioning the stent due to the convex portion of the outer peripheral surface biting into the lumen wall can be more effectively exhibited.

In a fifth aspect of the present invention, in the stent according to the first to fourth aspects, at least one of the first skeletal structure and the second skeletal structure is integrated with each other by electroforming or etching. It is formed with a structure.

According to the stent having a structure according to this aspect, the yield can be improved because the number of discarded parts can be reduced as compared with the laser cutting or the like, and the shape and material can be adjusted as appropriate. The degree of freedom in design can be improved.

In particular, when a mesh-shaped tube is adopted as the first skeletal structure or the second skeletal structure, by adopting one formed by electroforming or etching, a troublesome end such as joining at the tube opening end is adopted. It is also possible to eliminate the need for partial processing.

Further, when adopting a structure in which the first skeletal structure and the second skeletal structure are overlapped so as to be sandwiched between the inner peripheral side, the outer peripheral side, or the intermediate portion in the thickness direction in the thickness direction of the stent peripheral wall, appropriate masking, etc. By applying the above, it becomes possible to form the first skeleton structure and the second skeleton structure continuously and integrally by electroforming or etching. As a result, the stability and reliability of the characteristics can be significantly improved as compared with the fixation of the first skeletal structure and the second skeletal structure by subsequent adhesion or welding.

According to the stent having a structure according to the present invention, since the first skeletal structure and the second skeletal structure are complexly integrated to form a small gap efficiently and stably, the gap of the stent is formed. Problems such as plaque protrusion through and restenosis of the lumen can be effectively prevented. Further, since the stent having such a small gap can be placed in the lumen of the patient by one operation, the burden on the patient and the practitioner can be surely reduced.

The perspective view which shows the stent as the 1st Embodiment of this invention. FIG. 5 is an enlarged cross-sectional view showing a main part of the II-II cross section in FIG. It is a cross-sectional view which shows the main part of the stent as the 2nd Embodiment of this invention in an enlarged manner, and is the figure corresponding to FIG. The plan view which shows the stent as the 3rd Embodiment of this invention. FIG. 5 is a plan view showing a first skeletal structure constituting the stent shown in FIG. FIG. 5 is a plan view showing a second skeletal structure constituting the stent shown in FIG. The plan view which shows the stent as the 4th Embodiment of this invention. FIG. 5 is a plan view showing a first skeletal structure constituting the stent shown in FIG. 7. The perspective view which shows the stent as the 5th Embodiment of this invention. The plan view which shows another aspect in the stent of this invention. FIG. 5 is a plan view showing a first skeletal structure constituting the stent shown in FIG. FIG. 5 is a plan view showing a second skeletal structure constituting the stent shown in FIG. The perspective view which shows one aspect of the stent which can be grasped as an invention different from this invention. FIG. 3 is an enlarged perspective view showing a main part of the stent shown in FIG. FIG. 3 is an enlarged perspective view showing a main part of the stent shown in FIG. 13 from another direction. FIG. 3 is an enlarged perspective view showing a main part of the stent shown in FIG. 13 from yet another direction. The development view which shows the stent shown in FIG. 13 cut open in one part on the circumference. The plan view which shows another aspect of the stent which can be grasped as an invention different from this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, FIGS. 1 and 2 show a stent 10 as a first embodiment of the present invention. The stent 10 is formed with a peripheral wall structure in which a first skeletal structure 12 and a second skeletal structure 14 are superposed on each other inside and outside and are inseparably integrated. In FIGS. 1 and 2, the stent 10 is shown in a molded state before being contracted or expanded. Further, in the following description, the axial direction refers to the front-back direction of the paper surface in FIG. 2, which is the axial direction in which the stent 10 extends.

More specifically, the first skeletal structure 12 is a sleeve structure having a mesh-like peripheral wall. That is, the first skeleton structure 12 spirally winds in one direction in the circumferential direction (for example, clockwise in FIG. 2) in the axial direction and extends in the axial direction with a small diameter wire 16a and the other direction in the circumferential direction (for example). For example, a plurality of small-diameter wires 16b that are spirally wound (counterclockwise in FIG. 2) and extend in the axial direction are arranged and arranged at equal intervals. Therefore, in such a mesh-like skeleton structure, cells having a basic structure forming rhombic openings having a substantially constant size are formed as a repeating structure in which cells having a basic structure are continuously formed at constant pitches in the circumferential direction and the axial direction.

Each gap of a large number of cells in the mesh structure composed of the wires 16a and 16b is set as the first gap 18. That is, the gap 18 has a substantially constant size and is repeatedly provided at a constant pitch in the circumferential direction and the axial direction.

Further, the second skeleton structure 14 has a cylindrical coil structure in which a linear body 20 which is one strut extends spirally in the circumferential direction while being folded back in the axial direction. The second skeletal structure 14 formed by connecting one linear body 20 is formed by a link-shaped connecting portion 24 connecting portions adjacent to each other in the axial direction at a plurality of locations on the circumference. It is connected and reinforced. Therefore, the second skeleton structure 14 has a repeating structure in which cells of the basic structure that fold back in the axial direction at a substantially constant cycle are continuous at constant pitches in the circumferential direction and the axial direction, respectively.

Then, a large number of second gaps 26 arranged in a spiral shape are formed by cells of the second skeleton structure 14 formed by folding back the linear body 20 in the axial direction at a constant pitch. Further, the second gap 26 is repeatedly positioned at a constant pitch in the circumferential direction and the axial direction, respectively. In the present embodiment, the axial spacing of the wires 16a and 16b and the axial folding pitch of the linear body 20 so that the first gap 18 is smaller than the second gap 26. (Periodic cycle) etc. are set.

The stent 10 of the present embodiment has a shape in which the second skeletal structure 14 is superposed on the outer peripheral side with respect to the first skeletal structure 12 having such a structure. Then, in the stent 10, the first skeletal structure 12 and the second skeletal structure 14 are superposed on each other, and the first gap 18 is partitioned by the struts (linear bodies 20) of the second skeletal structure 14. The second gap 26 is partitioned by the wires 16a and 16b of the first skeleton structure 12 to make it smaller.

Specifically, in the radial direction of the stent 10, the linear body 20 constituting the second skeleton structure 14 is located on the first gap 18, and the first skeleton is placed on the second gap 26. The wires 16a and 16b constituting the structure 12 are located. As a result, the size of the gap penetrating the stent in the radial direction is reduced as compared with the case where the first skeletal structure 12 and the second skeletal structure 14 are present alone.

The axial dimensions of the first skeletal structure 12 and the second skeletal structure 14 are not limited in any way, and the other skeletal structure may protrude from the axial end of one skeletal structure. In the present embodiment, the axial dimensions of the first skeletal structure 12 and the second skeletal structure 14 are substantially equal. Further, the shape of the axial end portion of the first skeletal structure 12 is substantially the same as that of the second skeletal structure 14, so that the first skeletal structure 12 from the axial end portion of the second skeletal structure 14 Is prevented from protruding. Further, the radial width dimension of the first skeleton structure 12 and the second skeleton structure 14 is not limited in any way, but in the present embodiment, the radial width dimension of the second skeleton structure 14, that is, linear. The radial width dimension of the first skeleton structure 12, that is, the thickness dimension of the wires 16a and 16b is smaller than the thickness dimension of the body 20.

In the stent 10 having the above-mentioned shape, the first skeletal structure 12 and the second skeletal structure 14 are manufactured separately, and then the first and second skeletal structures 12 and 14 are superposed on each other and welded. In this embodiment, the stent 10 having the above-mentioned shape is formed by electroforming, although it may be fixed inseparably by bonding or bonding. As a result, the first skeletal structure 12 and the second skeletal structure 14 are inseparably and integrally formed. When the first skeleton structure 12 and the second skeleton structure 14 are manufactured separately, the manufacturing methods of the respective skeleton structures 12 and 14 are not limited in any way, and electroforming or laser cutting is not limited. Etc. Conventionally known manufacturing methods can be adopted.

Further, the stent 10 of the present embodiment is delivered to the narrowed portion of the lumen by, for example, a stent delivery catheter, and is expanded in diameter by a balloon provided in the stent delivery catheter to expand the narrowed portion. .. The material of the stent 10 is not limited in any way, but can be preferably formed of, for example, stainless steel. Alternatively, if the stent 10 is a self-expanding stent that automatically expands with the patient's body temperature after being released from the stent delivery catheter, for example, at least the first and second skeletal structures 12, 14 One is preferably formed of a nickel-titanium alloy.

Since the stent 10 of the present embodiment having the above-mentioned structure is formed in a shape in which the first skeleton structure 12 and the second skeleton structure 14 are overlapped with each other, the first skeleton structure 12 and the second skeleton structure 12 are formed. The size of the first gap 18 and the second gap 26 can be reduced as compared with the case where the skeleton structure 14 of the above is present alone. This can prevent plaque restenosis through the gaps in the stent and effectively prevent luminal restenosis.

Further, since the stent 10 is integrally formed with a shape in which the first skeletal structure 12 and the second skeletal structure 14 are overlapped with each other, the first skeletal structure 12 is used when a stent having a small gap is placed. It is not necessary to perform a plurality of operations such as indwelling the second skeletal structure 14 and the second skeletal structure 14 at different timings, and the second skeletal structure 14 can be placed in the lumen of the patient in one operation. This can surely reduce the burden on the patient and the practitioner.

In particular, in the present embodiment, the second skeletal structure 14 is superposed on the outer peripheral side with respect to the first skeletal structure 12, and the first skeletal structure 12 having a mesh structure is on the inner peripheral side of the stent 10. On the other hand, a second skeletal structure 14 having a coil structure that is folded back in the axial direction and extends spirally in the circumferential direction is located on the outer peripheral side of the stent 10. That is, since the first gap 18, which is a smaller gap, is located on the inner peripheral side of the stent 10, the inner peripheral surface of the stent 10 can be made a smooth surface with less unevenness, and the stent can be made. It is possible to prevent the occurrence of stagnation, turbulence, etc. of blood or the like passing through the inside of 10. As a result, problems such as the formation of a thrombus and the thrombus adhering to the stent and the blood vessel restenosis at the indwelling position of the stent can be effectively avoided. Further, since the second gap 26, which is a larger gap, is located on the outer peripheral side of the stent 10, unevenness can be formed on the outer peripheral surface of the stent 10 to be larger than the inner peripheral surface of the stent 10. At the time of diameter expansion, the convex portion formed on the outer peripheral surface of the stent 10, that is, the second skeletal structure 14 can be stably bitten into the lumen wall. As a result, the positioning effect of the stent 10 in the lumen can be exerted with high accuracy.

Further, since the stent 10 of the present embodiment is integrally formed by electroforming, it takes time and effort to separately form the first skeletal structure 12 and the second skeletal structure 14 and fix them to each other at the time of manufacturing. The stent 10 can be easily manufactured without the need for such work. Since at least the first mesh-shaped skeleton structure 12 is formed by electroforming, it is not necessary to perform end treatment such as connecting the ends of the wires 16a and 16b, respectively, which requires complicated work. Can be omitted.

Further, FIG. 3 shows a stent 28 as a second embodiment of the present invention. In the stent 28 of the present embodiment, the mesh-shaped first skeletal structure 29 is a coil-shaped second skeletal structure 14 that is spirally extended in the circumferential direction while being folded back in the axial direction. Is located in. In other words, the mesh-shaped first skeletal structure 29 is located in the second gap 26 of the coil-shaped second skeletal structure 14. As in the first embodiment, the radial dimension of the first skeletal structure 29 is smaller than the radial dimension of the second skeletal structure 14. Further, in the following description, the same members or parts as those in the first embodiment are designated by the same reference numerals as those in the first embodiment in the drawings, and detailed description thereof will be omitted.

That is, in the present embodiment, the stent 28 has a shape in which the first skeletal structure 29 and the second skeletal structure 14 are overlapped with each other, so that the second gap 26 is reduced. Specifically, in the radial direction of the stent 28, the wires 16a and 16b constituting the first skeletal structure 29 are located on the second gap 26, as compared with the case of the second skeletal structure 14 alone. The second gap 26 is reduced. As a result, the size of the gap penetrating the stent in the radial direction is reduced as compared with the case where the second skeletal structure 14 exists alone, and therefore, the size of the gap penetrating the stent is reduced in the radial direction. The same effect as that of the stent 10 can be exhibited.

In particular, since the first skeletal structure 29 is located in the middle portion in the thickness direction of the second skeletal structure 14, the first skeletal structure 12 as in the first embodiment is the second skeletal structure 14. The radial dimension of the stent 28 can be kept small as compared with the case where it is located on the inner peripheral side of the stent 28. As a result, the resistance of blood flow at the indwelling position of the stent 28 can be reduced, and the possibility that thrombus or the like adheres to the inner peripheral surface of the stent 28 and restenosis occurs can be reduced. In addition, the foreign body sensation felt by the patient can be stably reduced.

The stent 28 of the present embodiment is formed by electroforming. As a result, the stent can be easily manufactured even if the first skeletal structure and the second skeletal structure are separately formed as in the present embodiment and then the shape is difficult to be overlapped and fixed inside and outside. Can be done.

Next, FIG. 4 shows a stent 30 as a third embodiment of the present invention. The stent 30 of the present embodiment has a structure in which the second skeletal structure 34 shown in FIG. 6 is superposed on the outer peripheral side with respect to the first skeletal structure 32 shown in FIG. The second skeletal structures 32 and 34 are mesh-shaped, respectively. The gap in the first skeletal structure 32 is the first gap 36, and the gap in the second skeletal structure 34 is the second gap 38. The first skeletal structure 32 and the second skeletal structure 32 By superimposing the skeleton structure 34 of the above, the first and second gaps 36 and 38 are made smaller than each of the individual states. Also in this embodiment, the axial dimensions of the first skeletal structure 32 and the second skeletal structure 34 are substantially equal, and the first skeletal structure 32 and the second skeletal structure 34 are in the axial direction. They are superposed on each other over the entire length. The mesh-like skeleton structure may be composed of two wires 16a and 16b extending in opposite directions in the circumferential direction as in the first embodiment, and is also shown in FIGS. 4 to 6. As such, it can also be constructed by axially connecting the peaks of the annular struts that fold back in the axial direction and extend in the circumferential direction.

Further, in the present embodiment, the mesh spacing (distance between the annular struts adjacent to each other in the axial direction) in the first skeletal structure 32 and the mesh spacing in the second skeletal structure 34 are made equal to each other. , These meshes are out of phase with each other.

By superimposing the first skeletal structure 32 and the second skeletal structure 34 on each other, the struts constituting the second skeletal structure 34 are located on the first gap 36 in the radial direction of the stent 30. At the same time, since the struts constituting the first skeletal structure 32 are located on the second gap 38, the first and second gaps 36 and 38 can be made smaller than the single state.

Further, in the present embodiment, the first and second skeleton structures 32 and 34 are separately formed by electroforming. By forming the first and second skeletal structures 32 and 34 by electroforming, the stent 30 can be made thinner in the radial direction than a normal stent. The radial thickness dimension of the stent 30 is preferably 30 to 300 μm, more preferably 100 μm or less. Then, the second skeletal structure 34 is superposed on the outer peripheral side of the first skeletal structure 32, and these two skeletal structures 32, 34 are inseparably fixed to each other by means such as adhesion or welding. The stent 30 of the embodiment is configured. The methods for producing the first and second skeletal structures 32 and 34 are not limited in any way. For example, one of the first and second skeletal structures 32 and 34 is formed by electroforming, and the first and second skeletal structures 32 and 34 are formed by electroforming. The other may be formed by a method other than electroforming. Further, the stent 30 may be formed by electroforming in a shape in which both skeleton structures 32 and 34 are integrally overlapped.

Also in the stent 30 of the present embodiment having the above-mentioned structure, the gaps 36 and 38 are reduced by superimposing the first skeletal structure 32 and the second skeletal structure 34. The same effect as that of the first embodiment can be exhibited.

In particular, when a stent having a shape in which two mesh-like skeletal structures are superposed is placed, for example, the first stent is first placed in the lumen and then the second stent is placed on the inner peripheral side of the first stent. When the two stents are placed one on top of the other, the skeletal structure of the first stent and the skeletal structure of the second stent overlap each other and the gaps between them do not become small, resulting in plaque re-protrusion and lumen restenosis. Was not prevented. However, as in the stent 30 of the present embodiment, by superimposing the first and second skeletal structures 32 and 34 on each other and inseparably integrating them, the first and second gaps are formed before the stent is placed. 36, 38 are surely reduced. This can prevent plaque restenosis and lumen restenosis more stably.

Further, in a stent having such a mesh-like skeletal structure, wires and struts generally have a small diameter, and the stent strength may be insufficient. However, two skeletal structures are integrated in a radial direction. Thereby, the stent strength can be improved. Further, instead of simply forming a stent having a small gap, the gap is reduced by superimposing two skeletal structures, and the possibility of significantly impairing the flexibility of the stent is avoided.

The manufacturing methods of the first and second skeleton structures 32 and 34 as described above are not limited in any way, and any of them can be manufactured by a conventionally known method, but these are manufactured by electroforming. It is not necessary to carry out the work of edge treatment, and the manufacturing efficiency can be improved.

Next, FIG. 7 shows a stent 40 as a fourth embodiment of the present invention. The stent 40 of the present embodiment is configured by superimposing a second skeletal structure 44 that is out of phase with the first skeletal structure 42 on the outer peripheral side of the first skeletal structure 42 shown in FIG. Has been done. Each of the first and second skeletal structures 42 and 44 spirals in the circumferential direction while one linear body is folded back in the axial direction as in the second skeletal structure 14 in the first embodiment. It has a coil shape that extends in a shape, and has a repeating structure in which a substantially single structure (cell) is continuous in the circumferential direction and the axial direction.

Even in the stent 40 having such a structure, the gap in the first skeletal structure 42 and the gap in the second skeletal structure 44 are larger than those in the case where the first skeletal structure 42 and the second skeletal structure 44 are single units, respectively. Since both skeletal structures 42 and 44 are made smaller by overlapping them, the same effect as that of the stent 10 described in the first embodiment can be exhibited.

Next, FIG. 9 shows a stent 46 as a fifth embodiment of the present invention. This stent 46 is a stent indwelled in a bifurcation portion of the lumen, and includes a main trunk side stent 48 indwelled in the main trunk portion of the lumen and a side branch side stent 50 indwelled in the side branch portion of the lumen. It is configured to include. The main trunk side stent 48 and the side branch side stent 50 in the present embodiment each have the same structure as the stent 10 in the first embodiment. In FIG. 9, the side branch side is the upper right side in FIG. 9, while the main trunk side is the lower left side in FIG. Further, in FIG. 9, the axial direction of the stent 46 refers to a linear direction connecting the lower left and upper right in FIG.

The main trunk side stent 48 and the side branch side stent 50 are connected to each other by a connecting strut 52 and are continuous. Specifically, the end portion of the main trunk side stent 48 and the end portion of the side branch side stent 50 are integrally connected in the axial direction by a connecting strut 52. As a result, the linear body constituting the main trunk side stent 48 and the linear body constituting the side branch side stent 50 are connected, and are formed by a continuous linear body over the entire stent 46. .. That is, the main trunk side stent 48 and the side branch side stent 50 have an integral structure.

In the initial state shown in FIG. 9, the connecting strut 52 in the present embodiment is a portion extending linearly in the axial direction, and by bending or bending the connecting strut 52, the trunk side stent 48 And the lateral branch side stent 50 can be extended in different directions. As a result, at the bifurcation portion of the lumen, the main trunk side stent 48 can be inserted into the main trunk portion, while the side branch side stent 50 can be inserted into the side branch portion of the lumen.

The stent 46 of the present embodiment having the above-mentioned structure also adopts the same structure as the stent 10 of the first embodiment as the main trunk side stent 48 and the side branch side stent 50. The same effect as that of the first embodiment can be exhibited.

By the way, conventionally, when a stent is placed in the bifurcation part of the lumen, first, the first stent is placed in the trunk part of the lumen, and then a hole opened in the peripheral wall of the first stent. A second stent was placed in the side branch of the lumen through the part, but stagnation and turbulence such as blood flow occurred at the overlapping part of the first stent and the second stent. Thrombi and the like may occur, causing restenosis.

On the other hand, in the stent 46 of the present embodiment, a connecting strut 52 is provided at an axially intermediate portion of one stent, and the connecting strut 52 bends or bends to provide a stent for a branched lumen. 46 can be detained. That is, when the stent 46 is placed in the branched lumen, the trunk side stent 48 and the side branch side stent 50 do not overlap with each other, so that stagnation and turbulence of blood and the like are suppressed. The risk of restenosis can be further reduced.

The stent 46 of the present embodiment is preferably integrally formed by electroforming. For example, Japanese Patent Application Laid-Open No. 2009-508622 shows a stent in which a stent placed on the trunk side of the lumen and a stent placed on the side branch side of the lumen are connected to each other by welding. .. However, in the stent described in the above publication, since the portion to be bent or curved corresponding to the branching of the lumen is connected by welding, the bending strength may be insufficient. On the other hand, in the stent 46 of the present embodiment, since the connecting strut 52 is integrally formed with the trunk side stent 48 and the side branch side stent 50, the bending strength at the time of bending or bending of the connecting strut 52 Improvements can be made. In particular, by forming the stent 46 by electroforming, the material of the connecting strut 52 can be changed from that of the main trunk side stent 48 and the side branch side stent 50, so that it is possible to adopt a material that is more easily bent or curved. , The degree of freedom in design can be improved.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the specific description thereof, and is carried out in a mode in which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. Any such embodiment is included in the scope of the present invention as long as it does not deviate from the gist of the present invention.

For example, in the above-described embodiment, the coil-shaped skeleton structure is a structure in which one linear body is folded back in the axial direction and extends spirally in the circumferential direction, but the present invention is not limited to this mode. That is, as a coil-shaped skeleton structure, one linear body is formed as an annular body that is folded back in the axial direction and extends in an annular shape in the circumferential direction, and a plurality of annular bodies are connected by a link portion in the axial direction. May be adopted.

Further, in the first to fourth embodiments, the first skeletal structures 12, 32, 42 and the second skeletal structures 14, 34, 44 have substantially the same axial dimensions, and these are axial dimensions. It was overlapped over almost the entire length, but it is not limited to such a mode. That is, the first skeletal structure and the second skeletal structure need only be partially overlapped in the axial direction, and in the overlapping portion, the first gap or the first gap or the case where both skeletal structures are each alone is compared with the case where both skeletal structures are single. It suffices if the second gap is small.

Further, in the first, third, and fourth embodiments, the second skeletal structures 14, 34, and 44 are located on the outer peripheral side of the first skeletal structures 12, 32, 42, but the first The second skeletal structure may be located on the inner peripheral side of the skeletal structure.

Further, in the third and fourth embodiments, in the first skeletal structures 32 and 42 and the second skeletal structures 34 and 44, the sizes of the first gap and the second gap are made equal to each other. By making the phases of these skeletal structures different from each other, the gap is reduced in the state where the respective skeletal structures are overlapped, but the present invention is not limited to this. That is, by adopting the first skeleton structure and the second skeleton structure having the same size and phase of the gap and superimposing them by shifting them in the axial direction, the first gap is formed in the superposed portion. Alternatively, the second gap may be made smaller.

Alternatively, as in the stent 54 shown in FIG. 10, a first skeletal structure and a second skeletal structure having different gap sizes may be superimposed. That is, in the stent 54 shown in FIG. 10, the first skeletal structure 56 shown in FIG. 11 and the second skeletal structure 58 shown in FIG. 12 having different mesh spacings (gap sizes) are overlapped with each other. It is composed of being done. In particular, in this embodiment, the first gap 60 in the first skeletal structure 56 located on the inner peripheral side is made smaller than the second gap 62 in the second skeletal structure 58 located on the outer peripheral side. ing.

As in this embodiment, the sizes of the first gap 60 and the second gap 62 are different from each other, so that both skeleton structures 56 and 58 are both in the axial position and the circumferential position. By superimposing the skeletal structures 56 and 58, the first or second gaps 60 and 62 can be made smaller than those in a single state.

In particular, by making the first gap 60 in the first skeletal structure 56 located on the inner peripheral side smaller than the second gap 62 in the second skeletal structure 58, the inner peripheral surface of the stent 54 is made smaller than the outer peripheral surface. On the other hand, the outer peripheral surface of the stent 54 may have irregularities larger than the inner peripheral surface. As a result, stagnation and turbulence such as blood flow can be suppressed, thrombus formation and restenosis of the lumen are prevented, and the positioning effect in the lumen by the convex portion on the outer peripheral surface of the stent is stabilized. Can be demonstrated.

In the embodiment shown in FIG. 10, the first skeleton structure 56 and the second skeleton structure 58 each have a mesh shape, and the size of the gap in the mesh shape is different, but the present invention is limited to this aspect. It is not something that is done. That is, both the first skeleton structure and the second skeleton structure have a coil shape that extends spirally in the circumferential direction while being folded back in the axial direction as in the fourth embodiment, and the first and second skeleton structures are formed. By adopting skeletal structures having different sizes of the first and second gaps, when the first skeletal structure and the second skeletal structure are overlapped, the first gap and the second gap are used. May be smaller than the state of each unit. Even in such a case, the gap in the first skeletal structure located on the inner peripheral side is made smaller than the gap in the second skeletal structure located on the outer peripheral side, so that thrombus formation and lumen can be formed as described above. The effect of preventing restenosis and the effect of positioning in the lumen can be exerted.

Furthermore, in the fifth embodiment, the connecting strut 52 is composed of one linear portion connecting the end of the trunk side stent 48 and the end of the side branch side stent 50. The connecting strut may be composed of a plurality of linear portions. In such a case, it is preferable that the connecting struts are provided close to each other by being adjacent to each other in the circumferential direction in a part of the circumference, thereby maintaining the flexibility of the connecting struts in the bending direction. , Strength can be improved.

Further, in the fifth embodiment, the connecting strut 52 extends linearly in the axial direction in the initial state, but may be bent or curved in the axial direction, and the connecting strut 52 in the initial state may be formed. The shape of is not limited in any way.

Furthermore, in the fifth embodiment, the connecting strut 52 is integrally formed with the linear body 20 constituting the second skeletal structure 14, but the axis is an appropriate portion of the linear body 20. It may be composed of a connecting portion 24 that connects and reinforces in the direction.

Further, in the above embodiment, the stents 10, 28, 46 in the first, second and fifth embodiments and the first and second skeletal structures in the third and fourth embodiments and the embodiments shown in FIG. Although 32, 34, 42, 44, 56, 58 were formed by electroforming, etching may be adopted instead of or in combination with electroforming. When the first skeleton structure and the second skeleton structure are formed separately, one may be formed by electroforming or etching, and the other may be formed by a method other than electroforming or etching.

Furthermore, in the above-described embodiment, the two skeletal structures are formed in a shape in which the two skeletal structures are superposed on each other, but the shape may be such that three or more skeletal structures are superposed on each other. In such a case, any of the skeletal structures may be the first skeletal structure or the second skeletal structure, and by superimposing the first skeletal structure and the second skeletal structure, the first skeletal structure can be obtained. The gap or the second gap may be reduced.

When a plurality of first gaps in the first skeletal structure and second gaps in the second skeletal structure are formed, it is not necessary to reduce all the gaps, and the first and second gaps need not be reduced. It suffices that at least one gap in the first or second gap is smaller than in the case where the skeletal structure of is present alone.

Here, in the fifth embodiment, the embodiment in which the first skeletal structures 12 and 12, that is, the stent 64 shown in FIGS. 13 to 17 and the stent 66 shown in FIG. 18 are not provided with the present invention. It can be recognized as an independent invention that can solve different problems.

The stents 64 shown in FIGS. 13 to 17 are stents to be placed in the branch portion of the lumen, and are placed in the trunk side stent 68 placed in the trunk portion of the lumen and in the side branch portion of the lumen. Lumen-side stents 70 are continuously and integrally formed with each other via connecting struts 72.

In this embodiment, it is preferable that the outer diameter of the side branch stent 70 is smaller than the outer diameter of the main stent 68, corresponding to the diameter of the main trunk portion and the side branch portion of the lumen. Therefore, as shown in the developed view shown in FIG. 17, it is preferable to set the wave pitch in the circumferential direction of the trunk side stent 68 to be smaller than that of the side branch side stent 70.

Such a stent 64 can be formed by a conventionally known method such as electroforming or laser cutting, but it is preferably formed by electroforming because the degree of freedom in designing the thickness dimension and the material can be improved. .. Etching may also be employed in place of or in combination with electroforming. In the stent 64, one of the main trunk side stent 68 and the side branch side stent 70 may be formed by electroforming, and for example, a strut connected to the end portion of the main trunk side stent formed by a method other than electroforming. And the side branch side stent may be integrally formed.

Further, as in the stent 66 shown in FIG. 18, the main trunk side stent 74 and the side branch side stent 76 are arranged in a straight line extending in the same direction. May overlap each other in the length direction. The stent 66 in FIG. 18 is shown in a state of being placed at the bifurcation portion of the lumen, that is, a state in which the connecting strut 72 is bent in the axial direction, while the main trunk side stent 74 and the side branch side. A two-dot chain line indicates a state in which the stent 76 is arranged on a straight line extending in the same direction.

Here, at the end portion of the linear body on the side branch side stent 76 side that constitutes the skeletal structure of the main trunk side stent 74, the axial dimension is increased at a part on the circumference. As a result, the main trunk side stent 74 and the side branch side stent 76 are arranged in a straight line extending in the same direction, and the main trunk side stent 74 and the side branch side stent 76 are in the length direction (left-right direction in FIG. 18). Overlap on each other.

In this way, by forming the end of the main trunk side stent 74 to extend toward the side branch side stent 76 from the end of the side branch side stent 76 in a part of the circumference, the branch portion in the lumen is formed. Stents can be placed to cover a wider area, allowing treatment of a wider area within the lumen.

That is, the first aspect of the present invention is a stent indwelling in a bifurcated portion of the internal lumen, and a main trunk side skeletal structure constituting the main trunk side stent indwelling in the main trunk portion of the internal lumen. The side branch side skeletal structure constituting the side branch side stent indwelled in the side branch portion of the internal lumen is formed by coiled struts that extend continuously in the circumferential direction while folding back in the axial direction, and the trunk side. A connecting strut extending straddling between the ends of the stent and the side branch side stent is formed continuously with each of the coiled struts constituting the main trunk side stent and the side branch side stent, or the main trunk is formed. It is characterized in that the main trunk side stent and the side branch side stent have an integral structure by providing a connecting link for connecting the side stent and each of the coiled struts constituting the side branch side stent. Is what you do.

In the second aspect, in the stent according to the first aspect, the wave pitch in the trunk side skeletal structure of the trunk side stent is smaller than the wave pitch in the side branch side skeletal structure of the side branch side stent. It is what has been done.

In the third aspect, in the stent according to the first or second aspect, the peripheral wall on the opening end side of the main trunk side stent and the side branch side stent facing each other is formed on the main trunk side stent and the side branch side. The stents are arranged on a straight line extending in the same direction and overlap each other.

In the fourth aspect, in the stent according to any one of the first to third aspects, at least one of the trunk side stent and the side branch side stent has a structure in which at least one of the trunk side stent and the side branch side stent are integrated with each other by electroforming or etching. It is formed.

In addition, the stent having a structure according to the embodiment shown in FIGS. 1 to 12 and the embodiment shown in FIGS. 13 to 18 may be formed by a laminated structure of a plurality of types of metals. For example, by adopting a metal material whose ionization tendency is smaller in the inner layer than in the outer layer, the force to hold the lumen against the recoil of the blood vessel during balloon expansion is strong, and the skeleton becomes thinner over time, so that it is resistant to bending. It is also possible to improve the followability. For example, the outer layer may be made of magnesium, iron or the like, and the inner layer may be made of nickel titanium alloy, cobalt or the like. In this embodiment, it is sufficient that at least a part of the stent in the length direction and the circumferential direction has a laminated structure made of a plurality of types of metals, and the entire stent needs to have a laminated structure made of a plurality of types of metals. Absent.

Further, the stent having a structure according to the embodiment shown in FIGS. 1 to 12 and the embodiment shown in FIGS. 13 to 18 has a Y-shaped branched shape, a tapered shape, a thick-walled end shape, and a trunk tube portion. Stents with different diameters of the branch tube, stents with at least one of the trunk tube and branch tube having a tapered tube shape, stents partially tapered in the length direction, and stents with a partial taper in the length direction. It can be applied to various irregularly shaped stents such as stents with thick walls at the ends and center of the stent, stent body excluding the cover of covered stents, and stents that are curved or bent in the middle part in the length direction. is there. The stent that is curved or bent at the intermediate portion in the length direction is effective for a highly curved or bent site of a patient with advanced arteriosclerosis.

Furthermore, the stent having a structure according to the embodiment shown in FIGS. 1 to 12 and the embodiment shown in FIGS. 13 to 18 is subjected to thermal spraying or vacuum vapor deposition, which is known as a molding technique such as film formation as in electroforming. It may be formed. For example, a stent is formed by integrating a large number of sprayed particles of a material that has been melted or brought into a state close to it by heating into a predetermined shape, or a large number of particles of a material that has been vaporized or sublimated by heating are formed into a predetermined shape. It is also possible to form a stent by integrating with.

In addition, the stent having a structure according to the embodiment shown in FIGS. 1 to 12 and the embodiment shown in FIGS. 13 to 18 is also applied in the case of a flow diverter for treating a cerebral aneurysm. The flow diverter is, for example, an improved blood flow diversion device having a low pore space for endovascular treatment of a cerebral aneurysm. Further, the stent having a structure according to the embodiment shown in FIGS. 1 to 12 and the embodiment shown in FIGS. 13 to 18 is also applied to the tip portion in the stent retriever system. The stent retriever system is, for example, a net-shaped tubular thrombus recovery device for efficiently pressing and entwining thrombi with a net to remove them.

10,28,30,40,46,54: Stent, 12,32,42,56: First skeletal structure, 14,34,44,58: Second skeletal structure, 18,36,60: First Gap, 26, 38, 62: Second gap

Claims (5)

The first skeletal structure provided with the first gap and the second skeletal structure provided with the second gap are formed of a single structure integrally formed with each other, and the second structure is formed. The second gap in the skeletal structure of the above is reduced by the first skeletal structure, and
The first skeletal structure has a mesh shape in which cells having a basic structure forming a rhombic opening having a substantially constant size are continuous at constant pitches in the circumferential direction and the axial direction, respectively. The second skeletal structure is a cylindrical coil in which one linear body extends spirally in the circumferential direction while being folded back in the axial direction.
A stent in which the first skeletal structure is located and integrated in the intermediate portion in the thickness direction of the second skeletal structure. The first skeletal structure provided with the first gap and the second skeletal structure provided with the second gap are formed of a single structure integrally formed with each other.
Both the first skeletal structure and the second skeletal structure have a repeating structure in which cells having a basic structure forming rhombic openings of substantially constant size are continuous at constant pitches in the circumferential direction and the axial direction, respectively. The first skeletal structure and the second skeletal structure having the same mesh spacing are out of phase with each other, and the rhombic openings in these first skeletal structures are formed. By overlapping in the thickness direction of the peripheral wall so that the connecting part of the rhombic opening in the second skeletal structure is located in the central part,
The first gap in the first skeletal structure is reduced in the second skeletal structure, and the second gap in the second skeletal structure is reduced in the first skeletal structure. Stent. The first skeletal structure provided with the first gap and the second skeletal structure provided with the second gap are formed of a single structure integrally formed with each other.
Both the first skeletal structure and the second skeletal structure have a cylindrical coil shape in which one linear body extends spirally in the circumferential direction while being folded back in the axial direction. The skeletal structure and the second skeletal structure are overlapped in the thickness direction of the peripheral wall in a state where the phases are shifted from each other.
The first gap in the first skeletal structure is reduced in the second skeletal structure, and the second gap in the second skeletal structure is reduced in the first skeletal structure. Stent. The first gap in the first skeletal structure is made smaller than the second gap in the second skeletal structure, and the second skeletal structure is located on the outer peripheral side of the first skeletal structure. The stent according to claim 3 , which is superimposed. The stent according to any one of claims 1 to 4, wherein at least one of the first skeletal structure and the second skeletal structure is formed by electroforming or etching to have a structure integrated with each other.