JP2002529138A - Expanded stent and method for manufacturing expanded stent - Google Patents

Abstract

(57) Abstract: Disclosed is an expandable stent that can be placed in a blood vessel or other body lumen to maintain patency of the lumen. The stent has a plurality of interconnected stent modules. Each stent module has first and second segments joined together by first and second connectors located diametrically opposite the module. The first and second segments are formed in a sinusoidal pattern and are movable between a flat shape and an expanded shape. The stent modules are connected along a common longitudinal axis by interconnecting elements extending between connectors of adjacent modules. This arrangement results in a stent with the best longitudinal flexibility and radial stability. Modules can be manufactured from an even number of wire strands of approximately equal length using inexpensive equipment in an automated manufacturing method. In another embodiment of the invention, an implant is sandwiched between wire wall sections of a stent to deliver a drug to a target lesion site.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD [0001] The present application relates to an expandable stent that is opened and placed in a body lumen such as a blood vessel. The expandable stent is effective in treating atherosclerotic stenosis.

BACKGROUND OF THE INVENTION Cardiovascular disease is the leading cause of death in the United States and Canada. The condition of cardiovascular disease is commonly caused by the deposition of fatty spots on the coronary arteries, which is called atherosclerosis. Atherosclerosis results in a stenosis of the coronary arteries and a corresponding reduction in blood flow to the myocardium. This can ultimately result in serious clinical complications such as angina and myocardial infarction.

[0003] A stent is a small tubular device usually composed of a biocompatible metal, which is inserted into a blood vessel or the like to maintain the patency of a vessel lumen. Once the stent is open and deployed, the stent radially supports a portion of the vessel wall and helps prevent lumen occlusion due to atherosclerotic plaques.

[0004] Stents are generally deployed open with a thin walled intravascular balloon dilatation catheter. This procedure consists of mounting a compressed stent around an expandable balloon located at the catheter tip. The catheter is carefully guided by the physician to the desired location while the procedure is monitored on the display screen. For example, a catheter can be inserted into a patient's femoral artery, advanced to the iliac artery, the ascending artery, and finally to the coronary artery. Once the catheter is advanced to the desired position, the physician inflates the balloon to flatten the deposits and expand the stent from a compressed configuration to a fully expanded configuration that supports the vessel wall. The balloon is then contracted and the catheter is withdrawn from the patient.

[0005] To work effectively, a stent must exhibit both longitudinal flexibility and radial stiffness. Flexibility is required so that the physician can easily guide the catheter through the twists and turns in the vascular passageway when placing the stent. Radial stiffness is desired to ensure that the stent, once deployed, has mechanical stiffness that maintains the patency of the vessel lumen. In other words, the stent must have the ability to effectively prevent restenosis (ie, chronic or acute coronary artery occlusion following balloon angioplasty).

[0006] In order to satisfy the above requirements, various expandable stents have been proposed in the past. For example, US Patent No. 5, lau, et al. Issued May 7, 1996 to Lau et al.
No. 514,154 discloses a stent having a plurality of radially expandable cylindrical elements which are tied together and aligned on a common longitudinal axis. The individual elements are formed in a corrugated or serpentine pattern and have edges that project outward when the stent is expanded. Although the Lo et al. Stent shows good longitudinal flexibility, the protruding edge damages tissue when the protruding edge is attached to a vessel wall lesion to keep the stent in place. Have the ability. The stent element of Lo et al. Is preferably formed from a stainless steel tube that has been subjected to chemical etching and a laser pattern. Such a manufacturing process requires expensive equipment such as a mechanically controlled laser.

[0007] Canadian Patent No. 2,202,476 to Birdsall et al., Issued May 2, 1996, is also representative of the prior art. The patent relates to an articulated stent device having a plurality of stent segments formed from wires and arranged in a corrugated pattern. The stent segments are held together by a series of small welds that limit the overall longitudinal flexibility of the stent. In addition, the need to produce a large number of welds increases the cost of manufacture and limits the ability to produce small cross-section (ie, small size) stents.

[0008] It is also known in the prior art to use a stent in combination with an implant. For example, US Pat. No. 5,683,448 issued Nov. 4, 1997.
Discloses a combination of an endoluminal stent and a graft. The graft is located on the periphery or inside of the stent and is secured to the wire body of the stent by a plurality of ring members. Other existing prior art stents also typically have one wire wall that is not adapted to easily clamp the graft material to the wire body.

Accordingly, a need has arisen for an expanded stent that has improved longitudinal flexibility and radial strength properties and that can be manufactured in an automated process using inexpensive equipment. A need also exists for a stent that is specifically designed to transport the graft material to a target lesion by sandwiching the drug-coated graft material between the multiple wire wall sections of the stent.

SUMMARY OF THE INVENTION In accordance with the present invention, a stent having a plurality of separate stent modules is disclosed. Each module includes a first element having a first flexible wire strand and a second flexible wire strand, a second element having a third flexible wire strand and a fourth flexible wire strand, And fixing means for joining the second element together. The securing means comprises a first connector for coupling the first and second elements at a first location and a second connector for coupling the first and second elements at a second location opposite the first location. The first and second elements are alternating peaks (peaks).
) And a trough. Preferably, the peaks of the first element are aligned with the valleys of the second element, and the valleys of the first element are aligned with the peaks of the second element.

The first and second elements are movable between a substantially flat position and a cylindrically expanded position. In the flattened position, the first and second elements extend in a substantially common plane. In the expanded position, the first and second elements are annular in shape and are aligned to form a cylindrical opening.

Preferably, the first, second, third and fourth strands have approximately equal lengths,
Each strand has a semi-cylindrical shape in the extended position. The first and second elements have a plurality of equal length segments composed of multiple strands of flexible wire. Preferably, each of the first and second elements has 2 (n) wire strands, where n is an integer greater than or equal to one.

[0013] The present application discloses a method for securing one of a first and a second connector on one of a plurality of stent modules to one of a first and a second connector on an adjacent module. An elongated stent comprising a plurality of stent modules connected together along a directional axis. In one embodiment, the modules are secured to each other on alternate sides of the stent.

A method for forming a stent module comprising the following steps is also disclosed. (A) a first flexible wire strand bent into a loop and a second flexible wire strand bent into a loop
Providing a flexible wire strand; (b) connecting the first and second wire strands to each other by a first connector at a first location; and (c) connecting the first and second wire strands directly opposite the first location. Connecting each other by a second connector at a second position of the first and second connectors, wherein the first and second connectors subdivide the strand into first and second segments having substantially equal lengths. Forming a second segment into a sinusoidal waveform pattern having alternating peaks and valleys

[0015] A method for forming an elongated stent comprising the following steps is also disclosed. (A) forming a stent module according to the method described above; (b) securing the interconnecting element to one of the connectors on the stent module; (c) repeating the steps of subparagraphs (a) and (b) (D) aligning adjacent stent modules such that the first and second connectors on each module are longitudinally aligned. (E) connectors on the additional stent modules. (F) repeating steps (c) to (e) until a stent of a desired length is formed.

The drawings illustrate embodiments of the invention and should not be construed as limiting the spirit or scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows Applicant's stent 10 in an expanded configuration within a blood vessel 4 or other body lumen.
Is shown. The stent 10 is open and configurable within the blood vessel 4 by mounting on the expandable balloon 6 of a flexible catheter 8. As will be described in more detail below, after the balloon 6 has been deflated and the catheter 8 removed, the stent 10 remains in place in the blood vessel 4 and radially supports a portion of the vessel inner wall 9.

The stent 10 typically has a plurality of separate stent modules secured to one another. However, the stent 10 could have one module 12). As shown in FIG. 2, each module 12 includes a first segment 14 and a second segment 16. The first segment 14 and the second segment 16 are connected on both sides of each module 12 by a first connector 18 and a second connector 20. In the expanded configuration shown in FIG. 2, segments 14 and 16 are annular in shape and are longitudinally aligned to form a cylindrical opening 17 that allows blood flow within stent 10. Preferably, segments 14, 16 comprise flexible wire elements formed in a sinusoidal pattern having a plurality of peaks 43 and troughs 45 as shown in FIGS.

Each stent module 12 is individually expandable to fit the internal structure of the vessel wall 9. Connectors 18 and 20 are radiopaque to enhance support of the vessel wall and facilitate fluoroscopy. As best shown in FIG. 1, the peaks 43 and valleys 45 of the module segments 14, 16 are aligned along the longitudinal axis of the cylindrical opening 17 in the direction of the vessel 4 to be dilated (ie in the direction of blood flow). You.
Each module 12 is relatively short in length and rigid in the radial direction. By combining a plurality of modules 12 having such design characteristics, the stent 1
Zero gives a high degree of radial strength.

As shown in FIGS. 1 and 3, the various modules 12 that make up the stent 10 are interconnected by interconnecting elements 22. An interconnecting element 22 extends between connectors 18, 20 on adjacent modules 12, and may consist of, for example, a strand or loop of flexible wire. In the illustrated embodiment, the interconnecting element 2
The two are staggered on opposite sides of the stent 10 such that each pair of adjacent modules 12 is joined by one interconnecting element 22. This provides the stent 10 with a high degree of longitudinal flexibility that facilitates insertion of the stent 10 into a tortuous body lumen.

However, as will be appreciated by those skilled in the art, each pair of adjacent modules 12 may alternatively be connected by two connecting elements 22 (ie, one connecting element 22 is adjacent to an aligned side of the stent 10). Extending between the connectors 18, with a second connecting element 22 extending between adjacent connectors 20 aligned with the other side of the stent 10). Assuming that each pair of adjacent modules 12 are connected to each other by at least one interconnecting element 22, other alternative fixed combinations are also envisioned.

FIGS. 4 and 5 show steps of a method of making the stent module 12. A length of flexible wire 24 having a first strand 26 and a second strand 28 is provided. As shown in FIG. 4, the wire 24 has a first wire end 30 and a second wire end 32.
It is bent until it is juxtaposed. The wire ends 30, 32 are joined together by a first connector 18. Next, the second connector 20 is fixed to the wire 24 at a position directly opposite to the connector 18. Therefore, connectors 18 and 20 subdivide module 12 into a first segment 14 and a second segment 16 having approximately equal lengths.

The connectors 18, 20 and the wire strands 26, 28 are preferably constructed from medical grade stainless steel. Optionally, other biocompatible materials may be used.

In one embodiment of the present invention, connectors 18 and 20 may be small metal tubes surrounding wire 24 and mechanically compressed to hold connectors 18 and 20 in place. Wire strands 26 on both sides of the stent module 12
, 28 can be substituted. For example, connector 18,
20 may be a clip, a weld, or the like.

As will be appreciated by those skilled in the art, in another embodiment, module 12 may be fabricated from two separate wire strands 26 and 28 each formed in an endless loop without ends. . Such wire strands 26, 28 are aligned in parallel planes as shown in FIG. 4 and are joined together by connectors 18 and 20 at diametrically opposed locations. Thereby, module segments 14 and 16 having substantially equal lengths are formed.

The next step in the manufacturing process involves deforming the segments 14, 16 of each module 12 into a sinusoidal waveform pattern while keeping the modules 12 flat. As shown in FIG. 4, this is a wire strand 26, which constitutes segments 14, 16 using a template having first and second parts 36 and 38.
Achieved by bending 28. Each template component 36, 38 has one or more protruding finger portions 40. During the wire folding process, module 12 is supported on a plurality of spaced cylindrical pins 39 extending from plate 41.
As shown in FIG. 4, when the template parts 36 and 38 are moved closer to each other, the finger 40 passes between the stationary pins 39, and the segments 14 and 16 are divided into a plurality of peaks 43 and valleys 45. Fold it into a solid pattern. The pin 39 functions as a stopper that forms a peak 43 of the first segment 14 and a valley 45 of the second segment 16. Preferably, template sections 36, 38 and pins 39 are
The ridges 43 formed on the segment 14 are aligned with the valleys 45 of the segment 16, and the valleys 45 formed on the stent segment 14 are similarly formed with the ridges 43 of the segment 16 (FIG. 4). As will be appreciated by those skilled in the art, the number of peaks and valleys 43, 45 formed in the wire bending process may vary and is not a critical feature of the present invention (each wire strand 26 of each element 14, 16). , 28 is at least 1
Three peaks 43 or valleys 45).

The steps of the method of FIG. 4 produce a flat stent module 12 having wire strands 26 and 28 that extend and extend in substantially parallel planes as shown in FIG. To adjust the module 12 from this flattened configuration to the expanded configuration of FIG. 2, a mandrel 42 having a tapered conical end 44 is inserted between the wire strands 26 and 28 (FIG. 5) and each segment 14 , 16 into an annular shape forming a cylindrical opening 17 (FIG. 2).

If the stent 10 comprises a plurality of modules 12, the wire interconnecting elements 22
Are fixed to the connectors 18 and 20 on the adjacent module 12 during the manufacturing process,
This produces a flattened stent 10 as shown in FIG. For example, if the connectors 18, 20 consist of small tubes, the end of the interconnecting element 22 is inserted into one of the connectors 18, 20 before it is compressed. Similarly, the other end of the interconnecting element 22 is joined to connectors 18 and 20 on another stent module 12 manufactured according to the method steps shown in FIG. 4 and the like to form the stent 10 composed of a plurality of modules 12. .

As will be appreciated by those skilled in the art, the stent 10 may include a plurality of aligned modules 12.
, Each of the modules 12 can be adjusted from a flat shape (FIG. 6) to an expanded shape (FIG. 3) in a single step using a mandrel. This results in a cylindrical stent in which the modules 12 share a common longitudinal axis, as shown in FIG.

4 and 5 and Applicants' manufacturing method described above can be automated to reduce manufacturing costs. The method is easier to reproduce and more economical than conventional stent machining techniques using expensive laser cutting, etching and welding equipment. One significant advantage of Applicants' method is that module 12
Is a flat shape (FIG. 4) while the stent segments 14, 16 can be deformed into a desired sinusoidal pattern using inexpensive equipment.

In an alternative embodiment, the stent 10 may be a plurality of modules 12 arranged at a plurality of branches to support a plurality of portions of a blood vessel 4 or other body lumen that do not share a common axis. . This can be easily achieved by connecting each branch segment to one of the connectors 18, 20 on each side of one coupling module 12.

FIGS. 7 and 8 show that each module 12 has a flexible wire strand 26 a, 26 b
5 shows a further alternative embodiment of the present invention made according to the method of FIG. 4 from FIGS. To adjust such a module 12 from a flattened configuration to an expanded configuration, the mandrel 42 can be passed between the innermost wire strands 26b and 28a. This results in an expanded stent module 12 in which the wire strands 26a and 26b are closely spaced from each other, and similarly the wire strands 28a and 28b are closely spaced from each other (FIG. 7). The plurality of modules 12 thus formed are connected to one another by an interconnecting element 22 as described above and as shown in FIG.

The alternative embodiment of FIGS. 7 and 8 shows wire strands 26 a and 26 b and 2
It provides an opportunity to secure the implant 46 or other biocompatible substrate or barrier between each pair of 8a and 28b. Such an implant 46 may be coated or impregnated with, for example, an agent that inhibits stenosis thrombosis. Thus, in this alternative embodiment, the stent module 12 has the added ability to function as a drug delivery device. Also, the implant 46 may optionally be used as an endovascular prosthesis or barrier to seal an aneurysm, thrombus, perforation, or an entire vascular lesion. The transplant material 46
It may be one or more separate strips of material that can be placed side by side to extend between connectors 18 and 20 around all or a portion of the outer circumference of stent 10 (in FIG. 8, a single strip of graft material 46). Shows a part of one strip).

As will be appreciated by those skilled in the art, in a further alternative embodiment, to further provide an opportunity to sandwich the implant 46, the modules 12 may be 6, 8 or any other May be formed from an even number of wire strands.

In use, the stent 10 is formed according to the method steps described above and has a flattened shape (FIG. 6).
) To the expanded shape (FIG. 3). The stent 10 is then radially compressed against the inflated balloon 6 of the catheter 8 and transported to the target site. The catheter 8 is inserted into the blood vessel or other body lumen of the patient being treated and is carefully positioned at the desired location by the physician while being simultaneously monitored on the display screen. For example, a catheter can be inserted into a patient's femoral artery, advanced to the iliac artery, the ascending artery, and finally to the coronary artery. The interconnecting elements 22 allow each stent module 12 to flex with respect to the adjacent module 12 so that the stent 10
Has sufficient longitudinal flexibility to facilitate the passage of tortuous blood vessels and the like.

An important advantage of Applicants' invention is that stent 10 exhibits excellent radiopacity. In particular, the connectors 18, 20 of each module 12 are radiopaque and are easily visualized by a physician using fluoroscopy during the stent placement procedure. This ensures accurate delivery of the stent 10 to the target site by the physician.

[0036] Once the stent 20 is deployed at the target site, the balloon 6 is inflated,
As shown in FIG. 1, the stent 10 is expanded until the stent 10 contacts the inner wall 9 of the blood vessel. Each module 12 is independently expandable to allow placement and fit within a particular structure at a target site location. For example, a tapered balloon 6 can be used to conform to the shape of the target vessel or other lumen. Once the stent 10 is expanded, the balloon 6 is deflated and the stent 1
The catheter 8 is withdrawn from the blood vessel 4 while leaving 0 at the home position. In this installed position, the stent 10 is installed in a fixed position, and each stent module 12 radially supports a part of the blood vessel inner wall 9. The connectors 18 and 20 are located on opposite sides of each module 12 and the stent segments 14 and 16 have a sinusoidal corrugated pattern, which results in the best radial strength and stiffness of the stent 20 at the installation location.

When the alternative stent 10 of FIGS. 7 and 8 is used, the graft material 4 is designed to further support the vascular lining 9 and to function as a substrate for delivering the drug as described above.
6 can be placed at the target site.

As will be apparent to those skilled in the art, many changes and modifications can be made in practicing the present invention without departing from the spirit or scope of the invention. Therefore, the scope of the present invention should be construed according to the contents defined in the claims.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view showing a portion of a blood vessel showing Applicant's stent attached to a balloon catheter.

FIG. 2 is an isometric view showing one stent module.

FIG. 3 is an isometric view showing a stent with a plurality of interconnected stent modules shown in FIG. 2;

FIG. 4 is an isometric view illustrating a method for manufacturing a stent module according to the applicant's invention.

5 is an isometric view showing the steps of a method for adjusting a stent module from the process of FIG. 4 from a flat shape to an expanded shape.

FIG. 6 is an isometric view showing a flattened stent having a plurality of interconnected stent modules shown in FIG. 5;

FIG. 7 is an isometric view showing another stent module having closely spaced wire walls.

FIG. 8 is a partial isometric view of a stent with a plurality of stent modules shown in FIG. 7, suitable for holding an implant.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] February 2, 2001 (2001.2.2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

Patent application title: Expandable stent and method for manufacturing expanded stent

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD [0001] The present application relates to an expandable stent that is opened and placed in a body lumen such as a blood vessel. The expandable stent is effective in treating atherosclerotic stenosis.

BACKGROUND OF THE INVENTION Cardiovascular disease is the leading cause of death in the United States and Canada. The condition of cardiovascular disease is commonly caused by the deposition of fatty spots on the coronary arteries, which is called atherosclerosis. Atherosclerosis results in a stenosis of the coronary arteries and a corresponding reduction in blood flow to the myocardium. This can ultimately result in serious clinical complications such as angina and myocardial infarction.

[0003] A stent is a small tubular device usually composed of a biocompatible metal, which is inserted into a blood vessel or the like to maintain the patency of a vessel lumen. Once the stent is open and deployed, the stent radially supports a portion of the vessel wall and helps prevent lumen occlusion due to atherosclerotic plaques.

[0004] Stents are generally deployed open with a thin walled intravascular balloon dilatation catheter. This procedure consists of mounting a compressed stent around an expandable balloon located at the catheter tip. The catheter is carefully guided by the physician to the desired location while the procedure is monitored on the display screen. For example, a catheter can be inserted into a patient's femoral artery, advanced to the iliac artery, the ascending artery, and finally to the coronary artery. Once the catheter is advanced to the desired position, the physician inflates the balloon to flatten the deposits and expand the stent from a compressed configuration to a fully expanded configuration that supports the vessel wall. The balloon is then contracted and the catheter is withdrawn from the patient.

[0005] To work effectively, a stent must exhibit both longitudinal flexibility and radial stiffness. Flexibility is required so that the physician can easily guide the catheter through the twists and turns in the vascular passageway when placing the stent. Radial stiffness is desired to ensure that the stent, once deployed, has mechanical stiffness that maintains the patency of the vessel lumen. In other words, the stent must have the ability to effectively prevent restenosis (ie, chronic or acute coronary artery occlusion following balloon angioplasty).

[0006] In order to satisfy the above requirements, various expandable stents have been proposed in the past. For example, US Patent No. 5, lau, et al. Issued May 7, 1996 to Lau et al.
No. 514,154 discloses a stent having a plurality of radially expandable cylindrical elements which are tied together and aligned on a common longitudinal axis. The individual elements are formed in a corrugated or serpentine pattern and have edges that project outward when the stent is expanded. Although the Lo et al. Stent shows good longitudinal flexibility, the protruding edge damages tissue when the protruding edge is attached to a vessel wall lesion to keep the stent in place. Have the ability. The stent element of Lo et al. Is preferably formed from a stainless steel tube that has been subjected to chemical etching and a laser pattern. Such a manufacturing process requires expensive equipment such as a mechanically controlled laser.

[0007] Canadian Patent No. 2,202,476 to Birdsall et al., Issued May 2, 1996, is also representative of the prior art. The patent relates to an articulated stent device having a plurality of stent segments formed from wires and arranged in a corrugated pattern. The stent segments are held together by a series of small welds that limit the overall longitudinal flexibility of the stent. In addition, the need to produce a large number of welds increases the cost of manufacture and limits the ability to produce small cross-section (ie, small size) stents.

[0008] It is also known in the prior art to use a stent in combination with an implant. For example, US Pat. No. 5,683,448 issued Nov. 4, 1997.
Discloses a combination of an endoluminal stent and a graft. The graft is located on the periphery or inside of the stent and is secured to the wire body of the stent by a plurality of ring members. Other existing prior art stents also typically have one wire wall that is not adapted to easily clamp the graft material to the wire body.

[0009] Bogi International Application No. WO-A-96 No. 41591, published 1996 October 27 by (Borghi) from the module configuration in which a plurality of individual modules are connected to each other along the needle or wire Comprising an intravascular stent. Each module consists of a wire formed in a serpentine. Connector to attach to the support follower unpleasant collectively free end of the wire is given. And have you to one embodiment of the invention, may the second support wire is provided in the first support wire and the opposite position. In the invention of Bo formic, each individual module comprising one annular element which limits the radial strength of the stent. The annular element except as by the common elongate support wire not connected to each other. This essentially longitudinal Direction flexibility of the assembled stent is limited. Moreover, Bogie's device, once assembled , is not adapted to adjust between a flattened and cylindrical configuration.

[0010] Accordingly, a need has arisen for an expanded stent that has improved longitudinal flexibility and radial strength characteristics and that can be manufactured in an automated process using inexpensive equipment. A need also exists for a stent that is specifically designed to transport the graft material to a target lesion by sandwiching the drug-coated graft material between the multiple wire wall sections of the stent.

SUMMARY OF THE INVENTION In accordance with the present invention, a stent having a plurality of separate stent modules is disclosed. Each module includes a first element having a first flexible wire strand and a second flexible wire strand, a second element having a third flexible wire strand and a fourth flexible wire strand, And fixing means for joining the second element together. The securing means comprises a first connector for coupling the first and second elements at a first location and a second connector for coupling the first and second elements at a second location opposite the first location. The first and second elements are alternating peaks (peaks).
) And a trough. Preferably, the peaks of the first element are aligned with the valleys of the second element, and the valleys of the first element are aligned with the peaks of the second element.

The first and second elements are movable between a substantially flat position and a cylindrically expanded position. In the flattened position, the first and second elements extend in a substantially common plane. In the expanded position, the first and second elements are annular in shape and are aligned to form a cylindrical opening.

Preferably, the first, second, third and fourth strands have approximately equal lengths,
Each strand has a semi-cylindrical shape in the extended position. The first and second elements have a plurality of equal length segments composed of multiple strands of flexible wire. Preferably, each of the first and second elements has 2 (n) wire strands, where n is an integer greater than or equal to one.

[0014] The present application discloses a method of securing one of the first and second connectors on one of a plurality of stent modules to one of the first and second connectors on an adjacent module. An elongated stent comprising a plurality of stent modules connected together along a directional axis. In one embodiment, the modules are secured to each other on alternate sides of the stent.

A method for forming a stent module comprising the following steps is also disclosed. (A) a first flexible wire strand bent into a loop and a second flexible wire strand bent into a loop
Providing a flexible wire strand; (b) connecting the first and second wire strands to each other by a first connector at a first location; and (c) connecting the first and second wire strands directly opposite the first location. Connecting each other by a second connector at a second position of the first and second connectors, wherein the first and second connectors subdivide the strand into first and second segments having substantially equal lengths. Forming a second segment into a sinusoidal waveform pattern having alternating peaks and valleys

A method of forming an elongated stent comprising the following steps is also disclosed. (A) forming a stent module according to the method described above; (b) securing the interconnecting element to one of the connectors on the stent module; (c) repeating the steps of subparagraphs (a) and (b) (D) aligning adjacent stent modules such that the first and second connectors on each module are longitudinally aligned. (E) connectors on the additional stent modules. (F) repeating steps (c) to (e) until a stent of a desired length is formed.

The drawings illustrate embodiments of the present invention . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows Applicant's stent 10 in an expanded configuration within a blood vessel 4 or other body lumen.
Is shown. The stent 10 is open and configurable within the blood vessel 4 by mounting on the expandable balloon 6 of a flexible catheter 8. As will be described in more detail below, after the balloon 6 has been deflated and the catheter 8 removed, the stent 10 remains in place in the blood vessel 4 and radially supports a portion of the vessel inner wall 9.

The stent 10 typically has a plurality of separate stent modules secured to one another. However, the stent 10 could have one module 12). As shown in FIG. 2, each module 12 includes a first segment 14 and a second segment 16. The first segment 14 and the second segment 16 are connected on both sides of each module 12 by a first connector 18 and a second connector 20. In the expanded configuration shown in FIG. 2, segments 14 and 16 are annular in shape and are longitudinally aligned to form a cylindrical opening 17 that allows blood flow within stent 10. Preferably, segments 14, 16 comprise flexible wire elements formed in a sinusoidal pattern having a plurality of peaks 43 and troughs 45 as shown in FIGS.

Each stent module 12 is individually expandable to fit the internal structure of the vessel wall 9. Connectors 18 and 20 are radiopaque to enhance support of the vessel wall and facilitate fluoroscopy. As best shown in FIG. 1, the peaks 43 and valleys 45 of the module segments 14, 16 are aligned along the longitudinal axis of the cylindrical opening 17 in the direction of the vessel 4 to be dilated (ie in the direction of blood flow). You.
Each module 12 is relatively short in length and rigid in the radial direction. By combining a plurality of modules 12 having such design characteristics, the stent 1
Zero gives a high degree of radial strength.

As shown in FIGS. 1 and 3, the various modules 12 that make up the stent 10 are interconnected by interconnecting elements 22. An interconnecting element 22 extends between connectors 18, 20 on adjacent modules 12, and may consist of, for example, a strand or loop of flexible wire. In the illustrated embodiment, the interconnecting element 2
The two are staggered on opposite sides of the stent 10 such that each pair of adjacent modules 12 is joined by one interconnecting element 22. This provides the stent 10 with a high degree of longitudinal flexibility that facilitates insertion of the stent 10 into a tortuous body lumen.

However, as will be appreciated by those skilled in the art, each pair of adjacent modules 12 may alternatively be connected by two connecting elements 22 (ie, one connecting element 22 is aligned adjacent one side of the stent 10). Extending between the connectors 18, with a second connecting element 22 extending between adjacent connectors 20 aligned with the other side of the stent 10). Assuming that each pair of adjacent modules 12 are connected to each other by at least one interconnecting element 22, other alternative fixed combinations are also envisioned.

FIGS. 4 and 5 show steps of a method of making the stent module 12. A length of flexible wire 24 having a first strand 26 and a second strand 28 is provided. As shown in FIG. 4, the wire 24 has a first wire end 30 and a second wire end 32.
It is bent until it is juxtaposed. The wire ends 30, 32 are joined together by a first connector 18. Next, the second connector 20 is fixed to the wire 24 at a position directly opposite to the connector 18. Therefore, connectors 18 and 20 subdivide module 12 into a first segment 14 and a second segment 16 having approximately equal lengths.

The connectors 18, 20 and the wire strands 26, 28 are preferably constructed from medical grade stainless steel. Optionally, other biocompatible materials may be used.

In one embodiment of the present invention, connectors 18 and 20 may be small metal tubes that surround wires 24 and are mechanically compressed to hold connectors 18 and 20 in place. Wire strands 26 on both sides of the stent module 12
, 28 can be substituted. For example, connector 18,
20 may be a clip, a weld, or the like.

As will be appreciated by those skilled in the art, in another embodiment, module 12 may be fabricated from two separate wire strands 26 and 28 each formed in an endless loop without ends. . Such wire strands 26, 28 are aligned in parallel planes as shown in FIG. 4 and are joined together by connectors 18 and 20 at diametrically opposed locations. Thereby, module segments 14 and 16 having substantially equal lengths are formed.

The next step in the manufacturing process involves deforming the segments 14, 16 of each module 12 into a sinusoidal waveform pattern while keeping the modules 12 flat. As shown in FIG. 4, this is a wire strand 26, which constitutes segments 14, 16 using a template having first and second parts 36 and 38.
Achieved by bending 28. Each template component 36, 38 has one or more protruding finger portions 40. During the wire folding process, module 12 is supported on a plurality of spaced cylindrical pins 39 extending from plate 41.
As shown in FIG. 4, when the template parts 36 and 38 are moved closer to each other, the finger 40 passes between the stationary pins 39, and the segments 14 and 16 are divided into a plurality of peaks 43 and valleys 45. Fold it into a solid pattern. The pin 39 functions as a stopper that forms a peak 43 of the first segment 14 and a valley 45 of the second segment 16. Preferably, template sections 36, 38 and pins 39 are
The ridges 43 formed on the segment 14 are aligned with the valleys 45 of the segment 16, and the valleys 45 formed on the stent segment 14 are similarly formed with the ridges 43 of the segment 16 (FIG. 4). As will be appreciated by those skilled in the art, the number of peaks and valleys 43, 45 formed in the wire bending process may vary and is not a critical feature of the present invention (each wire strand 26 of each element 14, 16). , 28 is at least 1
Three peaks 43 or valleys 45).

The steps of the method of FIG. 4 produce a flat stent module 12 having wire strands 26 and 28 that extend and fold in substantially parallel planes as shown in FIG. To adjust the module 12 from this flattened configuration to the expanded configuration of FIG. 2, a mandrel 42 having a tapered conical end 44 is inserted between the wire strands 26 and 28 (FIG. 5) and each segment 14 , 16 into an annular shape forming a cylindrical opening 17 (FIG. 2).

If the stent 10 comprises a plurality of modules 12, the wire interconnecting elements 22
Are fixed to the connectors 18 and 20 on the adjacent module 12 during the manufacturing process,
This produces a flattened stent 10 as shown in FIG. For example, if the connectors 18, 20 consist of small tubes, the end of the interconnecting element 22 is inserted into one of the connectors 18, 20 before it is compressed. Similarly, the other end of the interconnecting element 22 is joined to connectors 18 and 20 on another stent module 12 manufactured according to the method steps shown in FIG. 4 and the like to form the stent 10 composed of a plurality of modules 12. .

As will be apparent to those skilled in the art, the stent 10 may be provided with a plurality of aligned modules 12.
, Each of the modules 12 can be adjusted from a flat shape (FIG. 6) to an expanded shape (FIG. 3) in a single step using a mandrel. This results in a cylindrical stent in which the modules 12 share a common longitudinal axis, as shown in FIG.

The manufacturing methods of Applicants described above with reference to FIGS. 4 and 5 and described above can be automated to reduce manufacturing costs. The method is easier to reproduce and more economical than conventional stent machining techniques using expensive laser cutting, etching and welding equipment. One significant advantage of Applicants' method is that module 12
Is a flat shape (FIG. 4) while the stent segments 14, 16 can be deformed into a desired sinusoidal pattern using inexpensive equipment.

In an alternative embodiment, the stent 10 may be a plurality of modules 12 disposed at a plurality of branches to support a plurality of portions of a blood vessel 4 or other body lumen that do not share a common axis. . This can be easily achieved by connecting each branch segment to one of the connectors 18, 20 on each side of one coupling module 12.

FIGS. 7 and 8 show that each module 12 has a flexible wire strand 26 a, 26 b
5 shows a further alternative embodiment of the present invention made according to the method of FIG. 4 from FIGS. To adjust such a module 12 from a flattened configuration to an expanded configuration, the mandrel 42 can be passed between the innermost wire strands 26b and 28a. This results in an expanded stent module 12 in which the wire strands 26a and 26b are closely spaced from each other, and similarly the wire strands 28a and 28b are closely spaced from each other (FIG. 7). The plurality of modules 12 thus formed are connected to one another by an interconnecting element 22 as described above and as shown in FIG.

The alternative embodiment of FIGS. 7 and 8 shows wire strands 26 a and 26 b and 2
It provides an opportunity to secure the implant 46 or other biocompatible substrate or barrier between each pair of 8a and 28b. Such an implant 46 may be coated or impregnated with, for example, an agent that inhibits stenosis thrombosis. Thus, in this alternative embodiment, the stent module 12 has the added ability to function as a drug delivery device. Also, the implant 46 may optionally be used as an endovascular prosthesis or barrier to seal an aneurysm, thrombus, perforation, or an entire vascular lesion. The transplant material 46
It may be one or more separate strips of material that can be placed side by side to extend between connectors 18 and 20 around all or a portion of the outer circumference of stent 10 (in FIG. 8, a single strip of graft material 46). Shows a part of one strip).

As will be appreciated by those skilled in the art, in a further alternative embodiment, the modules 12 may be 6, 8 or any other having approximately equal lengths to further provide an opportunity to sandwich the implant 46. May be formed from an even number of wire strands.

In use, the stent 10 is formed according to the method steps described above and has a flattened shape (FIG. 6).
) To the expanded shape (FIG. 3). The stent 10 is then radially compressed against the inflated balloon 6 of the catheter 8 and transported to the target site. The catheter 8 is inserted into the blood vessel or other body lumen of the patient being treated and is carefully positioned at the desired location by the physician while being simultaneously monitored on the display screen. For example, a catheter can be inserted into a patient's femoral artery, advanced to the iliac artery, the ascending artery, and finally to the coronary artery. The interconnecting elements 22 allow each stent module 12 to flex with respect to the adjacent module 12 so that the stent 10
Has sufficient longitudinal flexibility to facilitate the passage of tortuous blood vessels and the like.

An important advantage of Applicants' invention is that stent 10 exhibits excellent radiopacity. In particular, the connectors 18, 20 of each module 12 are radiopaque and are easily visualized by a physician using fluoroscopy during the stent placement procedure. This ensures accurate delivery of the stent 10 to the target site by the physician.

Once the stent 20 has been placed at the target site, the balloon 6 is inflated,
As shown in FIG. 1, the stent 10 is expanded until the stent 10 contacts the inner wall 9 of the blood vessel. Each module 12 is independently expandable to allow placement and fit within a particular structure at a target site location. For example, a tapered balloon 6 can be used to conform to the shape of the target vessel or other lumen. Once the stent 10 is expanded, the balloon 6 is deflated and the stent 1
The catheter 8 is withdrawn from the blood vessel 4 while leaving 0 at the home position. In this installed position, the stent 10 is installed in a fixed position, and each stent module 12 radially supports a part of the blood vessel inner wall 9. The connectors 18 and 20 are located on opposite sides of each module 12 and the stent segments 14 and 16 have a sinusoidal corrugated pattern, which results in the best radial strength and stiffness of the stent 20 at the installation location.

When the alternative stent 10 of FIGS. 7 and 8 is used, the graft material 4 is designed to further support the vascular lining 9 and to function as a substrate for delivering the drug as described above.
6 can be placed at the target site .

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view showing a portion of a blood vessel showing Applicant's stent attached to a balloon catheter.

FIG. 2 is an isometric view showing one stent module.

FIG. 3 is an isometric view showing a stent with a plurality of interconnected stent modules shown in FIG. 2;

FIG. 4 is an isometric view illustrating a method for manufacturing a stent module according to the applicant's invention.

5 is an isometric view showing the steps of a method for adjusting a stent module from the process of FIG. 4 from a flat shape to an expanded shape.

FIG. 6 is an isometric view showing a flattened stent having a plurality of interconnected stent modules shown in FIG. 5;

FIG. 7 is an isometric view showing another stent module having closely spaced wire walls.

FIG. 8 is a partial isometric view of a stent with a plurality of stent modules shown in FIG. 7, suitable for holding an implant.

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Claims (24)

[Claims] 1. A stent module comprising: (a) a first element having a first flexible wire strand and a second flexible wire strand; and (b) a third flexible wire strand and a fourth flexible wire strand. A second element having a flexible wire strand; and (c) fixing means for coupling the first and second elements to each other, wherein the fixing means comprises: (I) fixing the first and second elements to each other. A first connector coupled to each other at a first position; and (ii) a second connector coupled to each other at a second position opposite to the first position, wherein the first and second elements are coupled to each other; And a stent module wherein the second element is formed in a sinusoidal corrugated pattern having alternating peaks and valleys. 2. The valley of claim 1, wherein the ridge on the first element is aligned with the valley of the second element, and the valley on the first element is aligned with the ridge on the second element. Stent module. 3. The stent module according to claim 1, wherein said first and second elements are movable between a substantially planar flattened position and a cylindrical expanded position. 4. The stent module according to claim 3, wherein said first and second elements extend in a substantially common plane in said flattened position. 5. The stent module according to claim 1, wherein said first, second, third and fourth strands have substantially equal lengths. 6. The stent module according to claim 1, wherein said first and second elements are annular in shape in said expanded position and are aligned to form a cylindrical opening. 7. The stent module according to claim 6, wherein each of said first, second, third and fourth strands in said expanded position is semi-cylindrical. 8. The stent module according to claim 1, wherein said first and second connectors comprise tubes surrounding said first and second elements. 9. The stent module according to claim 1, wherein said first and second elements comprise equal length segments comprised of a multi-strand flexible wire. 10. The stent module according to claim 1, wherein each of said first and second elements has 2 (n) wire strands, where n is an integer greater than or equal to one. 11. The stent module according to claim 10, further comprising a graft material sandwiched between said wire strands when n is greater than one. 12. An elongated stent comprising a plurality of stent modules according to claim 1, wherein said plurality of modules are longitudinally aligned and said second module on one of said plurality of modules. A stent connected to one another by securing one of a first and second connector to one of the first and second connectors on an adjacent module of the plurality of modules. 13. The stent of claim 12, wherein the modules are secured to each other on alternate sides of the stent. 14. A method for manufacturing a stent module, comprising: (a) a first flexible wire strand bent in a loop shape and a second flexible wire strand bent in a loop shape.
Providing a flexible wire strand; (b) connecting the first and second wire strands at a first location with a first connector; and (c) connecting the first and second wire strands to the first. Connecting together by a second connector at a second position diametrically opposite the position, wherein the first and second connectors subdivide the strand into first and second segments having approximately equal lengths. And (d) forming the first and second segments into a sinusoidal waveform pattern having alternating peaks and valleys. 15. The method of claim 14, wherein said first and second segments extend in the same plane when said segments are formed in said sinusoidal waveform pattern. 16. The method according to claim 16, further comprising the step of separating said first and second flexible strands and deforming each of said first and second segments into an annular shape forming a cylindrical opening. Item 16. The method according to Item 15. 17. The method according to claim 14, wherein said first and second strands have approximately equal lengths. 18. A method of manufacturing an elongated stent, comprising: (a) forming a stent module according to the method of claim 14; and (b) interconnecting one of the connectors on the stent module. (C) repeating the steps of subparagraphs (a) and (b) above to form additional stent modules; and (d) the first and second connectors on each module are in the longitudinal direction. (E) securing an interconnecting element to one of the connectors on the further stent module; and (f) stent of a desired length. Repeating steps (c) to (e) until is formed. 19. A method of manufacturing an elongated stent, comprising: (a) forming a plurality of stent modules according to the method of claim 14; and (b) first and second on each of the modules. Aligning the stent modules adjacent to each other such that the connectors of the plurality of modules are longitudinally aligned; and (c) placing at least one of the connectors on one of the plurality of modules above an adjacent module of the plurality of modules. Securing the stent modules together by mating with at least one of the connectors of claim 1. 20. A stent module, comprising: (a) a first flexible wire strand formed in a loop shape; (b) a second flexible wire strand formed in a loop shape; A first coupling the first and second flexible strands together at a first location;
And (d) a second connector for coupling the first and second flexible strands at a second position diametrically opposite the first position, wherein the first and second connectors have substantially equal lengths. A stent module for subdividing said strands into first and second segments having: 21. The stent module according to claim 20, wherein each of said first and second segments is formed in a sinusoidal corrugated pattern. 22. The module as defined in claim 1, wherein the first and second strands extend in a substantially parallel plane and have an expanded shape in which the first and second strands are bent to form a cylindrical opening. 21. The stent module according to claim 20, wherein the stent module is adjustable between positions. 23. The stent module according to claim 20, wherein the first and second strands are endless loops composed of wires. 24. A stent having at least one stent module according to claim 20.