WO2022172891A1

WO2022172891A1 - In vivo indwelling member and method for manufacturing same

Info

Publication number: WO2022172891A1
Application number: PCT/JP2022/004689
Authority: WO
Inventors: 周平松下
Original assignee: テルモ株式会社
Priority date: 2021-02-10
Filing date: 2022-02-07
Publication date: 2022-08-18

Abstract

[Problem] To provide an in vivo indwelling member that inhibits the invasion of a vital tissue, etc. into a void at an end of a stent cover and reduces the risk of the stent cover breakage or stent dropout, and a method for manufacturing the same. [Solution] An in vivo indwelling member (10) comprising a tubular stent (20) and a stent cover (30) that is in a tubular shape with voids (32) and formed of fibers (31), wherein: the fibers (31) include a long fiber (31A) that is knitted so as to continue, while being turned over, in the form of wavy lines toward the circumferential direction of the stent cover (30), and at least one short fiber (31B) disposed at an end in the axial direction of the stent cover (30); a fiber part on the long fiber (31A), said fiber part being divided by the length from a turn-over point (34B) on one end side in the axial direction, through a turn-over point (34A) on the other end side in the axial direction, to another turn-over point (34B) on the one end side in the axial direction, is defined as a loop; and the short fiber (31B), which is positioned at the end in the axial direction, connects together circumferentially adjacent end loops (37) being convex toward the end side.

Description

In vivo indwelling article and manufacturing method thereof

The present invention relates to an in vivo indwelling article and a manufacturing method thereof.

A known method for treating a lesion in a biological lumen such as a blood vessel is to percutaneously introduce a therapeutic instrument such as a catheter into the biological lumen and treat the lesion from within the biological lumen. In such treatment methods, when the lesion is a stenotic lesion, the stenotic lesion is dilated with a balloon, and a stent, which is a medical device implanted in the body, is often placed in order to prevent restenosis after balloon dilation. . The surface of the stent is often coated with a drug that suppresses the migration and proliferation of vascular smooth muscle cells that cause restenosis. Such drug-coated stents are known as drug-eluting stents.

A stent has a tubular structure in which struts, which are linear structural elements, are formed in wavy and annular shapes and can be contracted and expanded in the radial direction. When a stent is placed in a lesion, an operator moves (delivers) a catheter with a contracted stent to the lesion. After the stent reaches the lesion, the operator manipulates the catheter to expand the stent and leave it in the lesion.

When plaque is present in the lesion to be placed, if the struts are pressed against the plaque by expansion of the stent, the plaque may crack and debris may occur. As a result, debris passes between struts and migrates into the blood, and in some cases, is trapped in blood vessels on the peripheral side, occluding the peripheral blood vessels, and causing peripheral tissue necrosis.

Patent Document 1 proposes an in-vivo indwelling device having a structure in which a stent is covered with a fabric woven with fibers or a knitted fabric (knit) woven with fibers as a stent cover having voids. The area surrounded by fibers, which corresponds to the voids in the stent cover, is smaller than the area surrounded by the struts, which corresponds to the voids in the stent. Therefore, debris generated by pressing of the struts is trapped in the stent cover, preventing migration of the debris into the blood. In addition, since the stent cover has voids, endothelial cells infiltrate through the voids of the stent cover after the in-vivo indwelling article is placed. This results in earlier endothelialization than without voids in the stent cover, reducing the risk of thrombosis.

U.S. Patent No. 10070976

In the knitted stent cover with voids, the fibers are alternately folded to form loops that are continuous in the circumferential direction, so that the loops are continuous in the circumferential direction. In addition, a specific loop during weaving of fibers and a loop formed at the same circumferential position after an arbitrary number of consecutive loops intersect while being displaced in the axial direction. By connecting the fibers in this way, the knit has a helical structure in which loops are connected in the circumferential direction and the axial direction. Thus, except for loops at the axial ends of the knit, any loop is constrained by adjacent loops on both axial sides. However, since the loops present at the ends in the axial direction do not have adjacent loops on one side in the axial direction, the loops may expand radially outward. If an in vivo tissue or the like is caught in the radially outwardly widened loop during delivery of the catheter, there is a risk of causing breakage of the knit or detachment of the stent.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, by suppressing the intrusion of tissues in the living body into gaps at the ends of a stent cover, thereby reducing the risk of breakage of the stent cover and detachment of the stent. An object of the present invention is to provide an in-vivo indwelling device and a manufacturing method thereof.

An indwelling device that achieves the above object includes a tubular stent that extends axially, has a distal end and a proximal end, is configured to be radially expandable and contractible, and has a gap; an indwelling article having a distal end and a proximal end and formed to be radially expandable and contractible and having a void, tubular, and made of a fiber stent cover, the stent cover comprising: The fibers are continuous in a wavy line in the circumferential direction of the stent cover while being folded, and are knitted into a long fiber and at least one short fiber arranged at an axial end of the stent cover. , and divided by the length from the folded portion on the one end side in the axial direction of the long fiber to the other folded portion on the one end side in the axial direction via the folded portion on the other axial end side The short fibers are defined as loops, and the short fibers are located at the ends in the axial direction and connect the loops that are adjacent in the circumferential direction and have a convex shape on the end side. and

In the indwelling device configured as described above, the loops located at the ends of the stent cover in the axial direction are constrained by other loops that are adjacent in the circumferential direction and connected via the short fibers. It is difficult to spread radially outward. Therefore, the risk of damage to the stent cover or detachment of the stent due to catching of tissue in the living body or the like is reduced. Also, the existence of voids within the loops and voids adjacent to the loops is maintained. Therefore, the delay of endothelialization is suppressed and the risk of thrombosis is suppressed because the invasiveness of endothelial cells is not impaired.

The short fiber may be located on the end side of the axial position where the loop at the end of the stent cover in the axial direction intersects another loop axially adjacent to the loop. If the radially outward expansion of the loop at the axial end occurs in the absence of short fibers, the loop will extend from the axial position where it intersects another axially adjacent loop to the end. It tries to expand radially outward at the side position. By providing the short fibers on the end portion side, the moment required for the loop to expand radially outward increases, thereby enhancing the effect of preventing the stent cover from expanding.

The length from the end of the short fiber on the axial end side of the stent cover to the folded portion on the end side of the loop connected by the short fiber may be shorter than the axial length of the loop. good. This reduces the risk of damage to the stent cover or detachment of the stent due to catching of tissue in the living body.

The position of the ends of the short fibers on the central side in the axial direction of the stent cover may be closer to the ends than the center position in the axial direction of the loops to which the short fibers connect. This increases the moment required for the loops located at the ends to expand radially outward, thereby increasing the effect of preventing the stent cover from expanding.

The short fiber has a convex shape with one convex portion facing the central side in the axial direction of the stent cover, and is connected only to two adjacent loops, and the end of the short fiber is connected to the loop. may be located on the end side of the folded portion on the end side of the stent cover. In addition to this, when the position of the ends of the short fibers on the axial center side of the stent cover is located on the end side of the axial center position of the loops to which the short fibers connect, the short fibers are at the ends. Compared to the case where the inner loop is divided along the circumferential direction, the reduction in the area of the void within the loop is suppressed. Therefore, the decrease in the invasiveness of endothelial cells is suppressed, and early endothelialization is promoted. And the risk of thrombus generation is further suppressed.

The radial thickness of the long fibers and the short fibers at the axial ends of the stent cover may be smaller than the radial thickness of the long fibers other than the ends. This reduces the outer diameter of the end portion and improves the passageability during delivery, so that the in-vivo implant can treat more peripheral lesions.

All the loops located at the ends in the axial direction of the stent cover may be connected by the short fibers. This further reduces the risk of the loop spreading radially outward. Therefore, the risk of damage to the stent cover or detachment of the stent due to catching of tissue in the living body or the like is reduced.

The loops at the ends of the adjacent stent covers may have fixed loop-to-loop connections. This further reduces the risk of the loop spreading radially outward. Therefore, the risk of damage to the stent cover or detachment of the stent due to tissue in the body being caught by the loops is reduced.

The stent cover may be within the axial length of the stent. This can prevent the axial ends of the stent cover from spreading undesirably outward in the radial direction. Therefore, the risk of damage to the stent cover or detachment of the stent due to catching of tissue in the living body or the like on the stent cover is reduced.

The stent cover may be made of a biodegradable material. As a result, the stent cover decomposes and disappears after the indwelling article is placed in the living body, thereby reducing the risk of a foreign body reaction starting from the stent cover.

A method for manufacturing an indwelling device that achieves the above object includes a tubular stent that extends axially, has a distal end and a proximal end, is formed to be capable of radial expansion and contraction, and has gaps. a preparation step of preparing a tubular fibrous member in which fibers are woven in a knitted shape so as to have a tubular shape; an inserting step of inserting a metal core member into the tubular fibrous member after the preparing step; a connecting step of connecting intersection positions of the woven fibers at a plurality of axially spaced connecting regions of the tubular fibrous member; a cutting step of cutting the tubular fiber member; an attaching step of attaching the stent cover obtained after the cutting step to the stent; and a removing step of removing the core metal member from the member or the stent cover.

In the method for manufacturing an indwelling instrument configured as described above, since the fibers of the loop at the cut position and the fibers of the loop axially adjacent thereto are connected at the crossing positions, the cut fibers are not cut. The fibers of the loops that were in position are prevented from remaining as fragments that can dislodge from the stent cover. As a result, in the in vivo indwelling article obtained by the present production method, the risk of the fragment flying into the living body and blocking the lumen of the living body after indwelling in the living body is reduced.

In the connecting step, all the crossing positions in the axial direction and the circumferential direction of the tubular fibrous members in each of the connecting regions may be connected. This results in an in-vivo implant in which all loops are connected by short fibers, further reducing the risk of loops spreading radially outward. Therefore, the risk of damage to the stent cover or detachment of the stent due to catching of tissue in the living body or the like on the stent cover is reduced.

In the connecting step, the intersecting position may be welded with an ultrasonic welder. This shortens the time required for the connection process. Also, thermal effects around the weld sites are reduced, reducing the risk of unintentionally reducing stent cover voids and impairing endothelial cell infiltration.

In the connecting step, the ultrasonic welding machine having a contact surface with a contact surface width wider than the width of the axial direction of the gap of the tubular fiber member is used, and in each connection region, the contact surface width is The contact surface may be brought into contact with the fibers and welded parallel to the axis of the member. As a result, even if the ultrasonic welding machine makes contact with the tubular fibrous member at any position in the axial direction, the intersecting position is reliably welded.

In the connecting step, the contact surface having the contact surface width narrower than the width in the axial direction of the region in which 10 voids of the tubular fibrous member are continuous in the axial direction may be used. As a result, the axial length of the connecting region is not excessively long, and the central region of the stent cover, which is excellent in expandability and contractibility and is not welded at the crossing points, is secured widely.

1 is a plan view showing an indwelling instrument and a balloon catheter according to an embodiment; FIG. FIG. 2 is a plan view showing an indwelling article in a living body; 1 is a plan view showing a stent; FIG. FIG. 4 is a plan view showing a portion of the stent cover; FIG. 4 is a plan view showing a portion of the stent cover; FIG. 11 is a plan view showing a modification of the stent cover; FIG. 4 is a diagram illustrating a method for manufacturing an indwelling device, in which (A) shows a state in which a protective tube and a core metal member are inserted into a tubular fiber member, and (B) shows a state in which a connection region is welded by an ultrasonic welding machine. , (C) shows the state in which the core metal member has been removed from the tubular fibrous member, (D) shows the state in which the tubular fibrous member has been cut, and (E) shows the completed stent cover after removing the protective tube. FIG. 4 is a perspective view showing an ultrasonic welding machine and a tubular fibrous member; FIG. 3 is a plan view showing part of another example of an indwelling instrument. FIG. 2 is a cross-sectional view of the indwelling device and balloon catheter in a contracted state, taken along line BB of FIG. 1;

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for convenience of explanation and may differ from the actual ratios.

The indwelling device 10 according to the present embodiment is used to treat lesions such as constrictions and obstructions occurring in blood vessels, bile ducts, trachea, esophagus, urethra, or other body lumens. The indwelling device 10 is used by being mounted on a known catheter. As an example, the indwelling device 10 is placed on the outer peripheral surface of the balloon 2 of the balloon catheter 1 and inserted into the body lumen, as shown in FIG.

A balloon catheter 1 has a balloon 2 at the distal end of a long shaft 3 that can be expanded by fluid supplied through the interior of the shaft 3 . The indwelling device 10 is placed on the outer peripheral surface of the deflated balloon 2 . The balloon 2 expands the lesion together with the indwelling object 10 by expanding at the lesion. Thereafter, when the balloon 2 is deflated, the indwelling device 10 is separated from the balloon 2 in an expanded state to maintain the patency of the lesion.

The indwelling device 10 has a stent 20 and a stent cover 30 covering the stent 20, as shown in FIG.

The stent 20 is, as shown in FIG. The stent 20 is mounted on the outer peripheral surface of the deflated balloon 2 . The stent 20 is formed in a circular tubular shape as a whole with linear struts 21 . The strut 21 is composed of a plurality of annular bodies 22 arranged in the axial direction of the balloon 2 and connecting elements 23 connecting the annular bodies 22 adjacent in the axial direction. In addition, the form of the stent 20 is not limited to this. Also, the stent 20 may be a so-called self-expanding stent 20 that expands by the restoring force of a superelastic alloy.

Each annular body 22 is formed by continuously arranging a plurality of linear elements 24 in the circumferential direction while folding them. Axially adjacent annular bodies 22 are integrally connected by connecting elements 23 . Adjacent annular bodies 22 are connected by connecting elements 23 at at least one point on the circumference along the circumferential direction intersecting the axial direction.

The widths of the wires of the linear elements 24 and the connecting elements 23 are not particularly limited, but are, for example, 30 to 500 μm. The wire lengths of the linear elements 24 and the connecting elements 23 are not particularly limited, but are, for example, 0.2 to 20 mm. The thickness of the wires of the linear elements 24 and the connecting elements 23 is not particularly limited, but is, for example, 30 to 500 μm. The outer diameter of stent 20 when expanded is approximately the same as the inner diameter of stent cover 30 when expanded, but may be larger or smaller. The axial length of stent 20 when expanded is approximately the same as the axial length of stent cover 30 when expanded, but may be longer or shorter.

The stent 20 is placed on the outer surface of the contracted balloon 2 in a radially contracted state. When the balloon 2 expands, the stent 20 widens the angle formed by the linear elements 24 adjacent in the circumferential direction, and the stent 20 expands radially.

For the constituent material of the stent 20, known materials can be applied, for example, metal materials such as stainless steel, cobalt-chromium alloys, and nickel-titanium alloys, polymer materials such as polylactic acid and polycaprolactone, and the like.

The stent cover 30, as shown in FIGS. 2 and 4-5, is formed in a tubular shape with a plurality of voids 32 by flexible fibers 31. As shown in FIG. Stent cover 30 has a central portion 33 between its axial distal and proximal ends. Stent cover 30 is within the axial length of stent 20 .

The fibers 31 of the stent cover 30 have long fibers 31A that are knitted into a tubular shape in a knit form, and a plurality of short fibers 31B that are arranged at the distal and proximal ends of the stent cover 30 in the axial direction. there is

The long fibers 31A extend from the folded portion 34B on the one axial end side of the long fiber 31A to the other folded portion 34B on the one axial end side via the folded portion 34A on the other axial end side. It has a plurality of loops 34 separated by length. The orientation of the one end and the orientation of the other end are not fixed and may be set each time. The plurality of loops 34 are continuously arranged in the circumferential direction of the stent cover 30 and arranged in a spiral. The original loop 34 and the loop 34 formed at the same circumferential position after the arbitrary number of continuous loops 34 cross each other while being displaced in the axial direction. By connecting the fibers 31 in this way, the knit has a tubular structure in which the loops 34 are connected in the circumferential direction and the axial direction. A plurality of circumferentially continuous loops 34 form different rows 38 every 360 degrees. Gap 32 is the area inside loop 34 .

Loops 34 include a plurality of end loops 37 at each axial end of stent cover 30 . Each end loop 37 is divided by the length from the folded portion 34B on the central portion 33 side to the other folded portion 34B on the central portion 33 side via the folded portion 34A on the end side. It has a convex shape toward

The stent cover 30 has a plurality of end voids 35 and a plurality of adjacent regions 36 at each axial end, as shown in FIG. The end gap 35 is the gap 32 formed by the end loop 37 which is convex towards the end and is the area inside the end loop 37 .

The adjacent region 36 is the gap 32 located between two circumferentially adjacent end gaps 35, as shown in FIG. That is, the adjacent region 36 is divided by the length from the folded portion 34A on the end side to the other folded portion 34A on the end side via the folded portion 34B on the central portion 33 side. It is the inner area of the loop 34 which is convex toward it. At each end of stent cover 30, end voids 35 and adjacent regions 36 alternate circumferentially.

Each short fiber 31B is connected to two circumferentially adjacent end loops 37 at a crossing position 39 in the connection range A of each axial end of the stent cover 30 . That is, the short fiber 31B is located between two circumferentially adjacent end loops 37 and connects the two end loops 37 . Each short fiber 31B is connected to one of the end loops 37 at four crossing points 39. As shown in FIG. The number of intersection positions 39 at which the end loops 37 are connected to each short fiber 31B is not limited, and may be at least one. Such connection between fibers means that the fibers are fixed to each other, and is formed by applying a method such as fusion fixation or adhesive fixation.

In the connection range A, the long fibers 31A may be connected to each other at the long fiber crossing positions 40 where the long fibers 31A cross each other like the crossing positions 39. The preferred range of the connection range A where the intersecting fibers 31 are connected is from each of the axial ends of the stent cover 30, moving from the end loops 37 of the stent cover 30 to the central part 33 side in the axial direction by four. The range includes up to the long fiber crossing position 40 where the fiber 31 of the previous loop 34 that has been moved and the fiber 31 of the previous loop 34 that has been moved five times crosses.

The short fibers 31B are small pieces cut and separated from the fibers 31 arranged at each end of the indwelling device 10 in the axial direction. The short fiber 31B is formed by cutting the loop 34 when cutting out the stent cover 30 having a predetermined length in the axial direction from the long tubular fiber member 60 (see FIG. 7) woven into a tubular shape. .

The interval between the rows 38 aligned in the axial direction during expansion, that is, the wale width W, which is the length of the fibers 31 extending in the circumferential direction that are displaced in the axial direction for each turn, is not particularly limited, but is, for example, 0.015 to 8. 0 mm, preferably 0.15 to 0.95 mm. The course width C, which is the interval between the loops 34 arranged in the circumferential direction when expanded, is not particularly limited, but is, for example, 0.01 to 5.0 mm, preferably 0.1 to 0.6 mm.

At a position P3 on the central portion 33 side of the short fiber 31B, the end loop 37 and another loop 34 arranged on the central portion 33 side of the end loop 37 and adjacent to the end loop 37 in the axial direction intersect. Although it is preferable to be on the end side of the position P2 in the axial direction, it is not limited to this. A distance L1 from the position P3 to the position P2 is assumed to be about 1/4 of the wale width W. Although the distance L1 is not particularly limited, it is preferably 0.00375 to 2.0 mm, more preferably 0.0375 to 0.2375 mm.

The distance L2 from the position P5 of the end of the short fiber 31B on the end side in the axial direction of the stent cover 30 to the position P4 of the folded portion 34A on the end side of the end loop 37 connected by the short fiber 31B is It is preferably shorter than the axial distance L3 of the end loop 37 (the distance L3 from the position P4 of the folded portion 34A on the end side of the end loop 37 to the position P1 of the folded portion 34B on the central portion 33 side). , but not limited to. The distance L2 is assumed to be approximately 0 to the wale width W. FIG. Although the distance L2 is not particularly limited, it is preferably 0 to 8.0 mm, more preferably 0 to 0.95 mm. The distance L3 is assumed to be about 5/4 of the wale width W. Although the distance L3 is not particularly limited, it is preferably 0.01875 to 10.0 mm, more preferably 0.1875 to 1.1875 mm.

The position P3 of the ends of the short fibers 31B on the axially central side of the stent cover 30 is the axial center position P6 of the end loops 37 to which the short fibers 31B connect (an intermediate position between the positions P4 and P1). Although it is preferable that it is closer to the edge, it is not limited to this. That is, the distance L4 from the position P3 to the position P1 is preferably longer than 1/2 of the distance L3 from the position P4 to the position P1, but is not limited to this. The distance L4 is assumed to be about 3/4 of the wale width W. Although the distance L4 is not particularly limited, it is preferably 0.01125 to 6.0 mm, more preferably 0.1125 to 0.7125 mm.

From the axial position P2 where the end loop 37 is arranged on the central portion 33 side of the end loop 37 and intersects the other loop 34 axially adjacent to the end loop 37 to the position P1 of the folded portion 34B on the central portion 33 side. is assumed to be about half the wale width W. Although the distance L5 is not particularly limited, it is preferably 0.0075 to 4.0 mm, more preferably 0.075 to 0.475 mm.

Each short fiber 31B has a convex shape with one convex portion facing the axial center side of the stent cover 30, and connects only two adjacent end loops 37, and both ends of each short fiber 31B is located on the end side of the connecting end loop 37 from the folded portion 34A on the end side of the stent cover 30 . Note that the two end loops 37 connected by the short fibers 31B may not be adjacent to each other. Also, the short fibers 31B may connect three or more end loops.

All the end loops 37 located at each end of the stent cover 30 are connected by short fibers 31B. A part of the end loops 37 may be connected by the short fibers 31B.

The radial thickness of the long fibers 31A and the short fibers 31B in the connection range A from the axial ends of the stent cover 30 to the central portion 33 is greater than the radial thickness of the long fibers 31A in the central portion 33. small. The radial thickness of the long fibers 31A and the short fibers 31B within the connection range A is equal to the radial thickness of the long fibers 31A within the central portion 33, or It may be larger than the thickness in the radial direction.

It should be noted that the stent cover 30 may have loop-to-loop connecting portions 31C in which circumferentially adjacent end loops 37 are directly connected to each other, as in the modification shown in FIG.

Although the fiber diameter of the fiber 31 is not particularly limited, it is, for example, 0.007 to 0.1 mm, preferably 0.01 to 0.03 mm. The outer diameter of the stent cover 30 when expanded is not particularly limited, but is, for example, 1.00 to 50.00 mm, preferably 2.25 to 4.00 mm. The axial length of the stent cover 30 is not particularly limited, but is, for example, 5-250 mm, preferably 12-38 mm.

The constituent material of the fibers 31 forming the stent cover 30 is not particularly limited, but biodegradable materials and non-biodegradable materials can be applied. Biodegradable materials are, for example, polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polydioxanone (PDO), trimethylene carbonate (PTMC), or copolymers thereof (bipolymer , terpolymers, quaternary copolymers) include glycolic acid-lactic acid copolymer (PGA-LA), glycolic acid-caprolactone copolymer (PGA-CL), and the like. Among these, polyglycolic acid, glycolic acid-lactic acid copolymer or glycolic acid-caprolactone copolymer is particularly preferred, and polyglycolic acid is more preferred. The elongation at break of polyglycolic acid is about 40%. Non-biodegradable materials include, for example, polyethylene terephthalate (PET), polyolefin (PO), acrylic oxide, polytetrafluoroethylene (PTFE), polyethylene co-vinyl acetate (PEVA), polyethylene elastomer, polyethylene oxide polybutylene terephthalate copolymer ( PEO-PBT), polyethylene oxide polylactic acid copolymer (PEO-PLA), polybutyl methacrylate (PBMA), polyurethane (PU), silicone-polycarbonate urethane copolymer (SPCU), medical grade polycarbonate urethane (PCU), Carboxylic acid moieties comprising one or more of polyamide (PA), polyetheretherketone (PEEK), polyacrylic acid (PAA), polymethacrylic acid (PMA), maleic acid, heronic acid, taconic acid and/or monomers thereof , thermoplastic polymers, thermoset polymers, polyolefin elastomers, polyesters, polyurethanes, polyfluoropolymers, and/or polyamide combinations and/or esters, and the like.

The stent cover 30 and the stent 20 may be fixed in whole or in part by known techniques such as gluing, fusing, or tying with thread. Securing the stent cover 30 and the stent 20 reduces the risk of the stent cover 30 falling off the stent 20 during delivery.

Next, the action of the indwelling object 10 according to this embodiment will be described.
In the indwelling device 10, as shown in FIGS. 2 and 4 and 5, the short fibers 31B of the stent cover 30 connect circumferentially adjacent end loops 37 of the axial ends of the stent cover 30. is doing. As a result, the end loops 37 are constrained by other end loops 37 that are adjacent in the circumferential direction and connected via the short fibers 31B, so that the end loops 37 are less likely to expand radially outward. Therefore, when the indwelling device 10 placed on the balloon 2 of the balloon catheter 1 is transported inside the lumen of the living body, there is a risk of causing damage to the stent cover 30 and dropping of the stent 20 due to catching of tissues in the living body. is reduced. Also, the existence of voids 32 within end loops 37 and voids 32 adjacent to end loops 37 is maintained. Therefore, the delay of endothelialization is suppressed and the risk of thrombosis is suppressed because the invasiveness of endothelial cells is not impaired. Moreover, since the short fibers 31B are connected to the long fibers 31A, the short fibers 31B do not fall off the stent cover 30. FIG. Therefore, the risk of blockage of the lumen on the peripheral side due to scattering of the short fibers 31B toward the periphery of the biological lumen is suppressed.

<Manufacturing method>
Next, a method for manufacturing the indwelling device 10 will be described with reference to FIG.

First, a tubular stent 20 and a tubular fibrous member 60 formed in a tubular shape by weaving fibers 31 in a knit so as to have voids 32 are prepared (preparation step). Next, as shown in FIG. 7A, for example, a stainless steel core member 100 covered with a PTFE protective tube 101 is inserted into the lumen of the tubular fiber member 60 (insertion step). Since the protection tube 101 is made of PTFE, it prevents the molten material from adhering to the core metal member 100 . In addition, the material of the protective tube 101 is not limited to PTFE as long as it is a material to which the melted material is difficult to stick. Also, the protective tube 101 may not be provided. Moreover, the material of the cored bar member 100 is not limited to stainless steel. The axial length of the tubular fiber member 60 is set to a length that allows a plurality of stent covers 30 to be cut out.

Next, as shown in FIGS. 7(B) and 8, a horn 110 of an ultrasonic welding machine is pressed against a plurality of connection regions CR on the outer peripheral surface of the tubular fibrous member 60 which are spaced apart in the axial direction. Horn 110 has a contact surface 111 that contacts tubular fibrous member 60 . The contact surface 111 is formed as an arc-shaped concave surface in the circumferential direction of the tubular fiber member 60 . In the axial direction of the tubular fiber member 60 , the contact surface width S of the contact surface 111 is wider than the width of the gap 32 (wale width W) of the tubular fiber member 60 . Therefore, even if the contact surface 111 comes into contact with the tubular fiber member 60 at any position in the axial direction, the contact surface 111 reliably comes into contact with the intersecting position. Next, while pressing the contact surface 111 against the fiber 31 of the tubular fiber member 60 by an ultrasonic welding machine, ultrasonic vibration is applied. As a result, the tubular fiber member 60 is heated by the vibration caused by the ultrasonic waves, a softening and melting phenomenon occurs, and the fibers 31 at the crossing positions are connected to each other (connecting step). In such ultrasonic welding, the surroundings of the contact surface 111 are less affected by heat, and the time required for welding is short. In each connection region CR, the contact surface 111 of the horn 110 contacts the outer peripheral surface of the tubular fibrous member 60 such that the contact surface width S is parallel to the axis of the tubular fibrous member 60 . In each connection region CR, the contact surface width S is the axial width of a region in which a plurality of, preferably 15, more preferably 10, and even more preferably 8 voids 32 of the tubular fibrous member 60 are continuous in the axial direction. Narrower than width, but not limited to this.

Subsequently, in order to ultrasonically weld the entire circumference of the connecting region CR of the tubular fiber member 60 by the horn 110, the tubular fiber member 60 and the horn 110 are relatively rotated, and a plurality of points in the circumferential direction of the connecting region CR are welded. Weld with At this time, the axial position of the horn 110 is fixed. As a result, the fibers 31 at the crossing positions are connected to each other in the entire circumference of the connection region CR of the tubular fiber member 60 . The axial length of the connection region CR is about twice the axial length of the connection range A to be finally formed.

The radial thickness of the fibers 31 in the connection region CR becomes smaller than the radial thickness of the fibers 31 other than the connection region CR due to the pressing of the horn 110 .

Next, as shown in FIG. 7(C), the core metal member 100 is removed from the tubular fiber member 60 (removal step). At this time, since the protective tube 101 is provided between the tubular fiber member 60 and the core metal member 100 , the core metal member 100 can be easily pulled out from the tubular fiber member 60 . Next, as shown in FIG. 7D, the tubular fiber member 60 is cut together with the protective tube 101 at the axial connection region CR of the tubular fiber member 60 (cutting step). The cutting position is approximately the center in the axial direction of each connection region CR. Thereby, both sides of the cut portion form a connection range A in which the fibers 31 in contact with each other at the axial ends of the different stent covers 30 are welded together. The step of removing the metal core member 100 from the tubular fiber member 60 may be performed after the tubular fiber member 60 is cut. In this case, the tubular fiber member 60 is cut together with the cored bar member 100 .

Next, as shown in FIG. 7(E), the protective tube 101 is removed from the stent cover 30 formed from the tubular fiber member 60 that has been cut. The protection tube 101 may be removed from the tubular fiber member 60 together with the core metal member 100 or after the core metal member 100 is removed in the removal step. After that, the outer periphery of the stent 20 is covered with the stent cover 30 and attached (attachment step). Thereby, the indwelling device 10 having the stent 20 and the stent cover 30 is completed.

After cutting the tubular fiber member 60, the ends of the cut member in the axial direction may be ultrasonically welded to form the connection range A in which the fibers 31 in contact are welded together.

Also, a plurality of horns 110 may be arranged side by side in the circumferential direction on the connection region CR, and the fibers 31 at intersecting positions may be simultaneously welded together at a plurality of circumferential locations in the connection region CR. The tubular fibrous member 60 and the plurality of horns 110 may then be rotated relative to one another. When a plurality of horns 110 are used, vibration of the tubular fiber member 60 due to ultrasonic vibration is suppressed, and variations in axial length and position of the connection region CR are suppressed in the circumferential direction.

Also, laser welding may be used instead of ultrasonic welding for connecting the fibers 31 at the crossing positions. When laser welding is used, since vibration is not applied to the tubular fiber member 60, variations in axial length and position of the connection region CR are suppressed in the circumferential direction. Also, the risk of damaging the material is reduced.

Also, the method of connecting the long fibers 31A and the short fibers 31B is not limited to ultrasonic welding or laser welding, and may be, for example, hot air welding, vibration welding, induction welding, high frequency welding, or heat welding. As a method of connecting the long fibers 31A and the short fibers 31B, a method of directly connecting the materials of the long fibers 31A and the short fibers 31B without using other members such as adhesives is preferable. .

As Example 1, the indwelling device 10 was manufactured by the manufacturing method described above.
The material of the fibers 31 of the prepared tubular fiber member 60 was PET, the fiber diameter was 27 μm, the course width C was 150 μm, and the wale width W was 250 μm. A protective tube 101 and a metal core member 100 were inserted into the tubular fiber member 60, and a horn 110 of an ultrasonic welding machine was pressed against the outer peripheral surface. The contact surface width S of the horn 110 was 2 mm, the radius of curvature of the contact surface 111 was 2 mm, and the width of the contact surface 111 perpendicular to the contact surface width S was 3 mm in horizontal distance. The frequency of the ultrasonic welding machine was 40 kHz, and the welding time was 1 second. Next, the connection position CR was cut at the center in the axial direction.

As a result, a stent cover 30 was obtained in which the fibers 31 that were in contact at the connection range A were connected. The short fibers 31B formed by the cutting process connected the end loops 37 of the circumferentially adjacent long fibers 31A. The obtained stent cover 30 was put on the separately prepared stent 20 to obtain the indwelling device 10 .

As described above, the indwelling device 10 according to the present embodiment is a tubular stent 20 that extends in the axial direction, has a distal end and a proximal end, is formed to be expandable and contractible in the radial direction, and has gaps. and an axially extending stent cover 30 having a distal end and a proximal end, configured to be radially expandable and contractible, tubular with voids 32, and formed of fibers 31. In the indwelling object 10, the fibers 31 of the stent cover 30 are folded back and continued in a wavy line in the circumferential direction of the stent cover 30. and at least one short fiber 31B disposed at the end of the long fiber 31A in the axial direction from the folded portion 34B on the one end side in the axial direction to the folded portion 34A on the other end side in the axial direction The fiber divided by the length up to the other folded portion 34B on one end side is defined as a loop, and the short fiber 31B is located at the end in the axial direction and adjacent in the circumferential direction, the end The end loops 37 that are convex on the sides are connected to each other.

In the indwelling device 10 configured as described above, the end loops 37 located at the ends in the axial direction of the stent cover 30 are circumferentially adjacent to each other and connected via the short fibers 31B. Since it is restrained by the partial loop 37, it is difficult to expand radially outward. Therefore, the risk of damage to the stent cover 30 or detachment of the stent 20 due to catching of tissue in the living body or the like is reduced. Also, the existence of the end voids 35 within the end loops 37 and the adjacent regions 36 adjacent to the end loops 37 is maintained. Therefore, the delay of endothelialization is suppressed and the risk of thrombosis is suppressed because the invasiveness of endothelial cells is not impaired.

In addition, the short fiber 31B extends from the axial position P2 where the end loop 37 at the end of the stent cover 30 in the axial direction and another loop 34 axially adjacent to the end loop 37 intersect. on the side. When the radially outward expansion of the loop 34 at the axial end occurs, the loop 34 moves toward the end from the axial position where it intersects another axially adjacent loop 34 as a fulcrum. Attempts to expand radially outward. By providing the short fibers 31B on the end portion side, the moment required for the loops 34 to expand radially outward increases, thereby increasing the effect of preventing the stent cover 30 from expanding.

In addition, the distance L2 from the end of the short fiber 31B on the end side in the axial direction of the stent cover 30 to the folded portion 34A on the end side of the end loop 37 to which the short fiber 31B connects is is shorter than the axial distance L3 of . This reduces the risk of damage to the stent cover 30 and detachment of the stent 20 due to catching of tissue in the living body.

In addition, the position P3 of the ends of the short fibers 31B on the central side in the axial direction of the stent cover 30 is closer to the end than the axial center position P6 of the loops 34 to which the short fibers 31B connect. As a result, the moment for the loops 34 located at the ends to expand radially outward increases, thereby enhancing the effect of preventing the stent cover 30 from expanding.

In addition, the short fiber 31B has a convex shape having one convex portion facing the central side in the axial direction of the stent cover 30, and is connected only to two adjacent end loops 37, and the end of the short fiber 31B is The connecting end loops 37 may be located on the end side of the folded portion 34A on the end side of the stent cover 30 . In addition to this, the position P3 of the ends of the short fibers 31B on the axial center side of the stent cover 30 is located on the end side of the axial center position P6 of the loops 34 to which the short fibers 31B connect. In this case, compared with the case where the short fibers 31B are arranged so as to divide the inside of the end loop 37 along the circumferential direction, the area of the void 32 in the end loop 37 is suppressed from decreasing. Therefore, the decrease in the invasiveness of endothelial cells is suppressed, and early endothelialization is promoted. And the risk of thrombus generation is further suppressed.

Further, the radial thickness of the long fibers 31A and the short fibers 31B at the axial ends of the stent cover 30 is smaller than the radial thickness of the long fibers 31A other than the ends. As a result, the outer diameter of the end portion is reduced, and the passageability during delivery is improved, so that the indwelling instrument 10 can treat more peripheral lesions.

In addition, all the end loops 37 located at the ends of the stent cover 30 in the axial direction are connected by short fibers 31B. This further reduces the risk of the end loops 37 spreading radially outwards. Therefore, the risk of damage to the stent cover 30 or detachment of the stent 20 due to catching of tissue in the living body or the like is reduced.

Also, the end loops 37 at the ends of adjacent stent covers 30 may have loop-to-loop connections 31C fixed to each other. This further reduces the risk of the end loops 37 spreading radially outwards. Therefore, the risk of causing damage to the stent cover 30 or detachment of the stent 20 due to the end loops 37 being caught by tissue in the living body or the like is reduced.

Also, the stent cover 30 is within the axial length of the stent 20 . As a result, the axial ends of the stent cover 30 can be prevented from spreading undesirably outward in the radial direction. Therefore, the risk of causing damage to the stent cover 30 or detachment of the stent 20 due to catching of tissue in the living body or the like on the stent cover 30 is reduced.

Also, the stent cover 30 may be made of a biodegradable material. As a result, the stent cover 30 decomposes and disappears after the indwelling device 10 is left in the living body, thereby reducing the risk of a foreign body reaction starting from the stent cover 30 .

In addition, the manufacturing method of the indwelling device 10 includes the tubular stent 20 which extends axially, has a distal end and a proximal end, is formed so as to be expandable and contractible in the radial direction, and has gaps, and the gaps 32 . a preparation step of preparing a tubular fibrous member 60 formed by knitting fibers in a knitted manner so as to have a tubular shape; an inserting step of inserting the core metal member 100 into the tubular fibrous member 60 after the preparing step; A connecting step of connecting intersection positions 39 of the woven fibers 31 in a plurality of connecting regions CR separated in the axial direction of the fiber member 60, and an axial position within the range of each connecting region CR after the connecting step. a cutting step of cutting the tubular fibrous member 60 with , an attaching step of attaching the stent cover 30 obtained after the cutting step to the stent 20, and a stage after the connecting step and before the attaching step, the tubular fibrous member 60 or a withdrawal step of withdrawing the core metal member 100 from the stent cover 30 .

In the manufacturing method of the indwelling device 10 configured as described above, the intersecting position 39 between the loop fiber 31 at the cut position and the loop fiber 31 axially adjacent thereto is connected. Therefore, the fibers 31 of the loops that were in the position where they were cut are prevented from remaining as fragments that can be dislodged from the stent cover 30 . As a result, in the indwelling device 10 obtained by the present manufacturing method, the risk of the fragment flying into the living body and blocking the lumen of the living body after being indwelled in the living body is reduced.

In addition, in the connecting step described above, all the axial and circumferential crossing positions 39 and long fiber crossing positions 40 of the tubular fiber member 60 in each connecting region CR are connected. As a result, the indwelling device 10 in which all the loops 34 are connected by the short fibers 31B is obtained, and the risk of the loops 34 expanding radially outward is further reduced. Therefore, the risk of causing damage to the stent cover 30 or detachment of the stent 20 due to catching of tissue in the living body or the like on the stent cover 30 is reduced.

Also, in the connection process described above, the intersection position 39 is welded with an ultrasonic welding machine. This shortens the time required for the connection process. In addition, the thermal effect around the weld site is reduced, and the risk of unintentionally reducing the voids 32 of the stent cover 30 and impairing the infiltration of endothelial cells is reduced.

Further, in the connecting step described above, an ultrasonic welding machine having a contact surface 111 having a contact surface width S that is wider than the axial width of the gap 32 of the tubular fiber member 60 is used. The contact surface 111 is brought into contact with the fiber 31 and welded so that S is parallel to the axis of the tubular fiber member 60 . As a result, even if the ultrasonic welding machine contacts the tubular fibrous member 60 at any position in the axial direction, the intersecting position 39 is reliably welded.

Further, in the connecting step described above, the contact surface 111 having a contact surface width S narrower than the axial width of the region in which ten voids 32 of the tubular fiber member 60 are continuous in the axial direction may be used. As a result, a wide area of the central portion 33 of the stent cover 30 with excellent expandability and shrinkability is ensured without welding the intersection points 39 because the axial length of the connection area CR is limited. be.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical concept of the present invention. For example, the shape of the short fibers 31B is not particularly limited, and may be straight, wavy, zigzag, or the like. Alternatively, as shown in FIG. 9, the short fibers 31B may extend in the circumferential direction of the stent cover 30 and be formed into a ring shape.

Also, the connection range A where the long fibers 31A and the short fibers 31B of the stent cover 30 are connected may be reduced in diameter to have a folded portion 30A, as shown in FIG. As a result, the diameter of the stent cover 30 in the connection range A is expanded so that the folded portion 30A is opened. As a result, even if the breaking elongation of the fiber 31 is small, the expansion diameter of the end portion of the stent cover 30 is ensured to be large, and breakage of the end portion of the stent cover 30 during expansion is prevented. Note that when the long fibers 31A and the short fibers 31B are made of a highly elastic material, the connection area A may be reduced in diameter without having a folding structure.

Also, the surface or inside of the stent 20 or the stent cover 30 may contain a known drug such as an immunosuppressant.

This application is based on Japanese Patent Application No. 2021-20192 filed on February 10, 2021, and the disclosure contents thereof are incorporated by reference.

1 Balloon Catheter 2 Balloon 3 Shaft 10 Indwelling Object 20 Stent 30 Stent Cover 31 Fiber

31A Long Fiber

31B Short Fiber 31C Connection between Loops 32 Gap 33 Central Part 34 Loop 35 End Gap (Gap)
36 Adjacent region (void)
37 end loops (loops)
38 row 39 crossing position 40 long fiber crossing position (crossing position)
60 Tubular fiber member 100 Core bar member 110 Horn 111 Contact surface CR Connection region S Contact surface width

Claims

an axially extending tubular stent having distal and proximal ends configured for radial expansion and contraction and having a gap;
an axially extending, distal and proximal end, configured to be radially expandable and contractible, a voided tubular, fiber-formed stent cover, wherein the stent cover comprises: ,
The fibers of the stent cover are
a continuous wavy fiber in the circumferential direction of the stent cover while being folded back and woven into a knit;
and at least one short fiber arranged at an end in the axial direction of the stent cover, from a folded portion on the one end side in the axial direction of the long fiber through a folded portion on the other end side in the axial direction. The fiber divided by the length up to the other folded part on one end side in the axial direction is defined as a loop,
The in-vivo indwelling article, wherein the short fibers are located at the ends in the axial direction, and connect the loops adjacent in the circumferential direction, which protrude toward the ends.
3. The short fiber is located on the end side of the axial position where the loop at the axial end of the stent cover intersects another loop axially adjacent to the loop. 1. The in vivo indwelling article according to 1.
The length from the ends of the short fibers on the axial end side of the stent cover to the folded portion on the end side of the loop connected by the short fibers is shorter than the axial length of the loop. 3. The in-vivo indwelling article according to claim 1 or 2.
3. The position of the ends of the short fibers on the central side in the axial direction of the stent cover is on the end side of the center position in the axial direction of the loops to which the short fibers connect. The in-vivo indwelling article according to any one of 1.
The short fiber has a convex shape with one convex portion facing the central side in the axial direction of the stent cover, and is connected only to two adjacent loops, and the end of the short fiber is connected to the loop. 5. The in-vivo indwelling device according to claim 4, wherein the stent cover is located on the end side of the folded portion on the end side of the stent cover.
Claims 1 to 3, characterized in that the radial thickness of the long fibers and the short fibers at the axial ends of the stent cover is smaller than the radial thickness of the long fibers other than the ends. 6. The in-vivo indwelling article according to any one of 5.
The in-vivo indwelling instrument according to any one of claims 1 to 6, wherein all the loops located at the ends of the stent cover in the axial direction are connected by the short fibers.
The in-vivo indwelling article according to any one of claims 1 to 6, characterized in that the loops at the ends of the adjacent stent covers have fixed inter-loop connections.
The in-vivo implant according to any one of claims 1 to 8, wherein the stent cover is within the axial length of the stent.
The in-vivo implant according to any one of claims 1 to 9, wherein the stent cover is made of a biodegradable material.
Axially extending, tubular stents formed to be radially expandable and contractible, having distal and proximal ends, having interstitial spaces and fibers knitted to form a tubular shape having voids. a preparatory step of preparing a tubular fibrous member;
an inserting step of inserting a metal core member into the tubular fiber member after the preparing step;
a connecting step of connecting crossing positions of the woven fibers in a plurality of connecting regions separated in the axial direction of the tubular fiber member after the inserting step;
a cutting step of cutting the tubular fibrous member at an axial position within each of the connection regions after the connecting step;
an attaching step of attaching the stent cover obtained after the cutting step to the stent;
a removing step of removing the core metal member from the tubular fiber member or the stent cover at any stage after the connecting step and before the attaching step. Production method.
12. The method for manufacturing an in-vivo implant according to claim 11, wherein, in the connecting step, all the crossing positions in the axial direction and the circumferential direction of the tubular fibrous members in each of the connecting regions are connected. .
The method for manufacturing an indwelling instrument according to claim 11 or 12, wherein in the connecting step, the intersecting positions are welded by an ultrasonic welder.
In the connecting step, the ultrasonic welding machine having a contact surface with a contact surface width wider than the width of the axial direction of the gap of the tubular fiber member is used, and in each connection region, the contact surface width is 14. The method for manufacturing an indwelling instrument according to claim 13, wherein the contact surface is brought into contact with the fiber so as to be parallel to the axis of the member.
15. The method according to claim 14, wherein, in said connecting step, said contact surface having said contact surface width narrower than said width in said axial direction of a region in which 10 voids of said tubular fibrous member are continuous in said axial direction is used. A method for producing an in vivo indwelling article according to