WO2007035023A1 - Stent for blood vessel - Google Patents

Stent for blood vessel Download PDF

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Publication number
WO2007035023A1
WO2007035023A1 PCT/KR2006/001673 KR2006001673W WO2007035023A1 WO 2007035023 A1 WO2007035023 A1 WO 2007035023A1 KR 2006001673 W KR2006001673 W KR 2006001673W WO 2007035023 A1 WO2007035023 A1 WO 2007035023A1
Authority
WO
WIPO (PCT)
Prior art keywords
struts
stent
blood vessel
hoops
present
Prior art date
Application number
PCT/KR2006/001673
Other languages
French (fr)
Inventor
Yang-Soo Jang
Yong-Sun Ryu
Jae-Mo Ahn
Original Assignee
Humed Co Ltd
Yang-Soo Jang
Yong-Sun Ryu
Jae-Mo Ahn
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Humed Co Ltd, Yang-Soo Jang, Yong-Sun Ryu, Jae-Mo Ahn filed Critical Humed Co Ltd
Publication of WO2007035023A1 publication Critical patent/WO2007035023A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A61F2/915—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
    • A61F2/06—Blood vessels
    • A61F2/07—Stent-grafts
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
    • A61F2/06—Blood vessels
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A61F2/915—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other
    • A61F2002/91508—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other the meander having a difference in amplitude along the band
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A61F2/915—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other
    • A61F2002/91516—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other the meander having a change in frequency along the band
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A61F2/915—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other
    • A61F2002/91533—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other characterised by the phase between adjacent bands
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A61F2/915—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other
    • A61F2002/9155—Adjacent bands being connected to each other
    • A61F2002/91558—Adjacent bands being connected to each other connected peak to peak
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/82—Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/86—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure
    • A61F2/90—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure
    • A61F2/91—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes
    • A61F2/915—Stents in a form characterised by the wire-like elements; Stents in the form characterised by a net-like or mesh-like structure characterised by a net-like or mesh-like structure made from perforated sheet material or tubes, e.g. perforated by laser cuts or etched holes with bands having a meander structure, adjacent bands being connected to each other
    • A61F2002/9155—Adjacent bands being connected to each other
    • A61F2002/91591—Locking connectors, e.g. using male-female connections
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2230/00—Geometry of prostheses classified in groups A61F2/00 - A61F2/26 or A61F2/82 or A61F9/00 or A61F11/00 or subgroups thereof
    • A61F2230/0002—Two-dimensional shapes, e.g. cross-sections
    • A61F2230/0028—Shapes in the form of latin or greek characters
    • A61F2230/0054—V-shaped

Definitions

  • the present invention relates to a blood vessel stent, and more particularly, to a blood vessel stent having a small diameter in a contracted state without reducing the thickness of struts, so that it can be easily inserted into a narrow blood vessel.
  • a stent is a medical instrument used to treat aneurysms, thrombosis, embolisms, and so on, and is a tubular structure disposed in a lumen of a blood vessel.
  • the stent is made of metal, such as nitinol, having superelastic and springy characteristic.
  • the stent is inserted into a lumen of a blood vessel in a contracted state using a catheter, and is then expanded at a target location either using a balloon or automatically.
  • the balloon-expandable stent is used together with a catheter equipped with a balloon.
  • the stent is inserted into a blood vessel along with a catheter in a state in which it is loaded on the outer circumference of the balloon, is moved to a target position, and then expands as the balloon expands, thereby outwardly pressing the wall of a blood vessel.
  • the balloon is contracted and then removed from the blood vessel along with the catheter.
  • the stent is permanently disposed at the target location, improving blood flow by maintaining the blood vessel in a expanded state.
  • a self-expandable stent has a relatively large diameter in a contracted state. Accordingly, this stent is used to treat a blood vessel having a relatively large diameter, such as carotid artery or popliteal artery.
  • This stent is transferred to a target position in a blood vessel in a state in which it is loaded in a catheter, and is pushed out from the inside of the catheter using an additional instrument inserted into the catheter, and then expanded automatically, so that the stent is disposed at the target location.
  • This type of stent has strong elastic resilience, so that it can endure a high pressure and is not easily deformed.
  • a conventional stent 100 has a tubular shape, in which a plurality of ring- shaped hoops 106a to 106b are sequentially coupled along a central axis 103 of the stent 100.
  • Each of the hoops 106a to 106d comprises a plurality of struts 108, which are made of a spring metal or a highly elastic metal and are arranged around the circumference of said ring shape in a zigzag manner, and a plurality of loops 110 which connect the facing ends of struts 108 to each other.
  • Each of the hoops 106a to 106d is formed by connecting the plurality of struts 108 to each other in a ring shape, so that each of the hoops 106a to 106d has a radial force by which each of the hoops can automatically expand, and also has a structure of being contracted inwardly.
  • the stent 100 includes a plurality of bridges 114.
  • Each bridge 114 connects respective facing ends of struts 108 of adjacent hoops 106a to 106d to each other, so that the hoops 106a to 106d can be coupled in a length direction of the stent 100.
  • the bridge 114 is formed by a laser welding method, etc.
  • the struts 108 arranged in a zigzag manner are plastically deformed to come into closer contact with each other, as shown in FIG. 1, so that the stent 100 is contracted to have a diameter dl.
  • the stent 100 has a size such that it can be easily transferred into a blood vessel by being loaded in a catheter.
  • the stent 100 transferred to a target location and then unloaded from a catheter is expanded by radial force due to the elasticity of the struts 108 of respective hoops 106a to 106d, so that the stent 100 has an increased diameter d2, as shown in FIG. 2, thereby outwardly pressing the wall of a blood vessel at the target location and becoming fixedly disposed in the target location in the blood vessel.
  • the stent shown in FIG. 1 and FIG. 2 has bridges, not all the stents have the same kind of shape. Some stents may have different shapes of bridges, and some stents may have no bridge with their struts directly coupled to each other without using bridges.
  • the material of the stent and the number of struts, the number of loops, and the number of bridges are important design parameters to determine the operational characteristic and fatigue life for a blood vessel stent.
  • the radial force of the stent depends on the elastic modulus of the material of the stent. Accordingly, it is important to carefully select the material of the stent.
  • radial force may vary according to the thickness of the struts. Accordingly, the thickness of the strut is also an important design parameter when determining the radial force of the stent.
  • the stent As the strut of the stent becomes thicker, the radial force may increase, but the diameter of the stent in a contracted state becomes larger. Accordingly, if the struts of the stent are thick, the stent can be easily inserted into a wide blood vessel, such as a carotid artery or popliteal artery, while it is difficult to insert the stent into a narrow blood vessel, such as a coronary artery.
  • a wide blood vessel such as a carotid artery or popliteal artery
  • the stent in the case of the self-expandable stent, since the stent must expand by itself without external aid, the stent must have strong radial force. However, there is a problem in that the stent has a large diameter in a contracted state so that it can hardly be inserted into a narrow blood vessel, such as a coronary artery.
  • the present invention has been devised in consideration of the aforementioned problems and situations, and an object of the present invention is to provide a stent having strong radial force by increasing the thickness of respective struts while having a small diameter in a contracted state.
  • a stent including a hoop comprising a plurality of struts that form a ring shape by connecting the struts in a zigzag manner around a circumference of said ring shape, thereby having a radial force, wherein the hoop comprises a plurality of first struts, a plurality of second struts, each pair of the second struts disposed between the two first struts, connecting the two first struts and bent and inclined inwardly, and a plurality of third struts, each connecting the pairs of the second struts.
  • the stent may comprise a plurality of the hoops, wherein ends of the first struts of each of the hoops are connected to ends of the first struts in adjacent hoops to form a tubular shape.
  • the second struts has a length shorter than that of the first struts
  • the third struts has a length shorter than that of the second struts
  • the stent according to the present invention has the following advantages. First, since the stent has a structure such that the struts can overlap with each other in a contracted state, the stent has strong radial force because of the relatively thick struts while having a small diameter in a contracted state, thereby being capable of easily being inserted into a relatively narrow blood vessel.
  • the stent according to the present invention can be applied to a balloon-expandable type stent and to the self-expandalbe type stent.
  • the present invention is applied to the self-expandable type stent, a problem that the stent of this type can hardly be used to treat a relatively narrow blood vessel can be overcome.
  • FIG. 1 is a perspective view illustrating a conventional stent
  • FIG. 2 is a perspective view illustrating part of a hoop of the stent shown in FIG. 1, when the stent is in an expanded state;
  • FIG. 3 is a perspective view illustrating a blood vessel stent in a contracted state according to an embodiment of the present invention
  • FIG. 4 is a left-side view of the blood vessel stent of FIG. 3;
  • FIG. 5 is a perspective view illustrating the blood vessel stent in an expanded state according to the embodiment of the present invention.
  • FIG. 6 is a plan view illustrating the blood vessel stent shown in FIG. 5, when cut in a lengthwise direction and shown in a development view;
  • FIG. 7 is a perspective view illustrating a main part including a first strut, a second strut, and a third strut of the stent in the expanded state according to the embodiment of the present invention.
  • FIG. 8 is a perspective view illustrating the main part including the first strut, the second strut, and the third strut of the stent in the contracted state according to the embodiment of the present invention.
  • FIG. 3 is a perspective view illustrating a blood vessel stent in a contracted state according to an embodiment of the present invention.
  • FIG. 4 is a left-side view of the blood vessel stent of FIG. 3.
  • FIG. 5 is a perspective view illustrating the blood vessel stent in an expanded state according to the embodiment of the present invention.
  • FIG. 6 is a plan view illustrating the blood vessel stent shown in FIG. 5, wherein the blood vessel stent is cut in a lengthwise direction and shown in a development view.
  • the stent according to the preferred embodiment of the present invention includes a plurality of ring-shaped hoops 12a to 12d coupled in the length direction of the stent, thereby having a tubular shape.
  • the hoops 12a to 12d can be coupled by connecting the ends of first struts 14 of each of the hoops that face each other.
  • the ends of the first struts 14 are connected through a micro- welding method using a laser, etc.
  • the struts in each of the hoops 12a to 12d form a ring shape by connecting the struts in a zigzag manner around a circumference of said ring shape.
  • the struts in the stent includes a plurality of first struts 14 having a predetermined first length Ll, a plurality of second struts 16 having a predetermined second length L2, a pair of which are arranged between two first struts 14, and a plurality of third struts 18 having a predetermined third length L3 for connecting the pairs of the second struts 16.
  • the first to third struts 14, 16 and 18 may be made by cutting a metal plate using laser or twisting a wire.
  • a plurality of second struts 16 are bent and inclined inwardly at an inclination angle ⁇ (see FIG. 7), so that the second struts 16 are disposed to the inner side of the first struts 16, and the third struts 18 are disposed to the inner side of the second struts 16.
  • each of the hoops 12a to 12d can be smaller than the sum of the total thickness of the first struts 14, the total thickness of the second struts 16 and the total thickness of the third struts 18 for each of the hoops. Further, the diameter of each of the hoops 12a to 12d, which is equal to the diameter of the stent 10, decreases.
  • the stent 10 according to the present invention has a structure in which struts 14, 16 and 18 can overlap with each other, and thus although the total thickness of the strut is thicker than that of the conventional one, the diameter of the stent is smaller than that of the conventional one.
  • the conventional stent has struts that cannot overlap with each other because the struts interfere with each other by facial contact in a contracted state. Accordingly, the circumference of the conventional stent cannot be less than the sum of the total thicknesses of struts.
  • the stent since the stent has strong radial force because of the increased thickness of struts, while having a small diameter, it can be easily inserted into a narrow blood vessel, such as a coronary artery.
  • the first struts 14 have a predetermined first length Ll
  • the second struts 16 have a predetermined second length L2 shorter than the first length Ll
  • the third struts 18 have a predetermined third length L3 shorter than the second length L2.
  • first struts 14 act to exert radial force by elasticity and to outwardly press the wall of a blood vessel, they need to have a large area. Accordingly, they are designed to be longer than the other struts 16 and 18. On the other hand, since the second struts 16 and the third struts 18 only act to generate radial force by elasticity, they do not need to be long.
  • the second and third struts 16 and 18 are designed to be shorter than the first struts 14, it is possible to prevent interference between ends of the second struts 16 and the third struts 18 of adjacent hoops 12a to 12d when the hoops 12a to 12d are connected to each other.
  • the configuration that the second struts 16 and the third struts 18 are shorter than the first struts 14 is not essential to achieve the objects of the present invention.
  • the struts 14, 16 and 18 can have the same length.
  • a stent has a structure in which a plurality of hoops are connected to each other.
  • This type of stent is used to treat a diseased part having a large area.
  • the stent may comprise a single hoop.

Abstract

Disclosed is a stent for blood vessels, structured in a manner such that struts overlap with each other in a contracted state, thereby being capable of easily being inserted into a narrow blood vessel because it has a small diameter in a contracted state while having a strong radial force. This stent can be applied to a balloon-expandable type stent and to a self-expandable type stent. Accordingly, if the present invention is applied to the self-expandable type stent, a problem that the stent of this type can hardly be used to treat a narrow blood vessel can be overcome.

Description

Description STENT FOR BLOOD VESSEL
Technical Field
[1] The present invention relates to a blood vessel stent, and more particularly, to a blood vessel stent having a small diameter in a contracted state without reducing the thickness of struts, so that it can be easily inserted into a narrow blood vessel. Background Art
[2] Generally, a stent is a medical instrument used to treat aneurysms, thrombosis, embolisms, and so on, and is a tubular structure disposed in a lumen of a blood vessel. The stent is made of metal, such as nitinol, having superelastic and springy characteristic.
[3] The stent is inserted into a lumen of a blood vessel in a contracted state using a catheter, and is then expanded at a target location either using a balloon or automatically.
[4] The balloon-expandable stent is used together with a catheter equipped with a balloon. The stent is inserted into a blood vessel along with a catheter in a state in which it is loaded on the outer circumference of the balloon, is moved to a target position, and then expands as the balloon expands, thereby outwardly pressing the wall of a blood vessel. After the stent expands, the balloon is contracted and then removed from the blood vessel along with the catheter. After the balloon is removed, the stent is permanently disposed at the target location, improving blood flow by maintaining the blood vessel in a expanded state.
[5] A self-expandable stent has a relatively large diameter in a contracted state. Accordingly, this stent is used to treat a blood vessel having a relatively large diameter, such as carotid artery or popliteal artery. This stent is transferred to a target position in a blood vessel in a state in which it is loaded in a catheter, and is pushed out from the inside of the catheter using an additional instrument inserted into the catheter, and then expanded automatically, so that the stent is disposed at the target location. This type of stent has strong elastic resilience, so that it can endure a high pressure and is not easily deformed.
[6] There are conventional stents having a variety of shapes. Referring to FIG. 1 and
FIG. 2, a conventional stent 100 has a tubular shape, in which a plurality of ring- shaped hoops 106a to 106b are sequentially coupled along a central axis 103 of the stent 100.
[7] Each of the hoops 106a to 106d comprises a plurality of struts 108, which are made of a spring metal or a highly elastic metal and are arranged around the circumference of said ring shape in a zigzag manner, and a plurality of loops 110 which connect the facing ends of struts 108 to each other.
[8] Each of the hoops 106a to 106d is formed by connecting the plurality of struts 108 to each other in a ring shape, so that each of the hoops 106a to 106d has a radial force by which each of the hoops can automatically expand, and also has a structure of being contracted inwardly.
[9] The stent 100 includes a plurality of bridges 114. Each bridge 114 connects respective facing ends of struts 108 of adjacent hoops 106a to 106d to each other, so that the hoops 106a to 106d can be coupled in a length direction of the stent 100. The bridge 114 is formed by a laser welding method, etc.
[10] If an external force is applied to the outer surface of the stent 100, the struts 108 arranged in a zigzag manner are plastically deformed to come into closer contact with each other, as shown in FIG. 1, so that the stent 100 is contracted to have a diameter dl. As a result, the stent 100 has a size such that it can be easily transferred into a blood vessel by being loaded in a catheter.
[11] The stent 100 transferred to a target location and then unloaded from a catheter is expanded by radial force due to the elasticity of the struts 108 of respective hoops 106a to 106d, so that the stent 100 has an increased diameter d2, as shown in FIG. 2, thereby outwardly pressing the wall of a blood vessel at the target location and becoming fixedly disposed in the target location in the blood vessel.
[12] Although the stent shown in FIG. 1 and FIG. 2 has bridges, not all the stents have the same kind of shape. Some stents may have different shapes of bridges, and some stents may have no bridge with their struts directly coupled to each other without using bridges.
Disclosure of Invention Technical Problem
[13] Generally, in a stent, the material of the stent and the number of struts, the number of loops, and the number of bridges are important design parameters to determine the operational characteristic and fatigue life for a blood vessel stent. In particular, the radial force of the stent depends on the elastic modulus of the material of the stent. Accordingly, it is important to carefully select the material of the stent. However, even if the material of the struts is identical, radial force may vary according to the thickness of the struts. Accordingly, the thickness of the strut is also an important design parameter when determining the radial force of the stent.
[14] As the strut of the stent becomes thicker, the radial force may increase, but the diameter of the stent in a contracted state becomes larger. Accordingly, if the struts of the stent are thick, the stent can be easily inserted into a wide blood vessel, such as a carotid artery or popliteal artery, while it is difficult to insert the stent into a narrow blood vessel, such as a coronary artery.
[15] However, in the case of the self-expandable stent, since the stent must expand by itself without external aid, the stent must have strong radial force. However, there is a problem in that the stent has a large diameter in a contracted state so that it can hardly be inserted into a narrow blood vessel, such as a coronary artery.
[16] The present invention has been devised in consideration of the aforementioned problems and situations, and an object of the present invention is to provide a stent having strong radial force by increasing the thickness of respective struts while having a small diameter in a contracted state. Technical Solution
[17] In order to achieve the above objects and advantages, according to one aspect of the present invention, a stent is provided including a hoop comprising a plurality of struts that form a ring shape by connecting the struts in a zigzag manner around a circumference of said ring shape, thereby having a radial force, wherein the hoop comprises a plurality of first struts, a plurality of second struts, each pair of the second struts disposed between the two first struts, connecting the two first struts and bent and inclined inwardly, and a plurality of third struts, each connecting the pairs of the second struts.
[18] In the present invention, the stent may comprise a plurality of the hoops, wherein ends of the first struts of each of the hoops are connected to ends of the first struts in adjacent hoops to form a tubular shape.
[19] In the present invention, the second struts has a length shorter than that of the first struts, and the third struts has a length shorter than that of the second struts.
Advantageous Effects
[20] The stent according to the present invention has the following advantages. First, since the stent has a structure such that the struts can overlap with each other in a contracted state, the stent has strong radial force because of the relatively thick struts while having a small diameter in a contracted state, thereby being capable of easily being inserted into a relatively narrow blood vessel.
[21] The stent according to the present invention can be applied to a balloon-expandable type stent and to the self-expandalbe type stent. In particular, if the present invention is applied to the self-expandable type stent, a problem that the stent of this type can hardly be used to treat a relatively narrow blood vessel can be overcome. Brief Description of the Drawings
[22] FIG. 1 is a perspective view illustrating a conventional stent;
[23] FIG. 2 is a perspective view illustrating part of a hoop of the stent shown in FIG. 1, when the stent is in an expanded state;
[24] FIG. 3 is a perspective view illustrating a blood vessel stent in a contracted state according to an embodiment of the present invention;
[25] FIG. 4 is a left-side view of the blood vessel stent of FIG. 3;
[26] FIG. 5 is a perspective view illustrating the blood vessel stent in an expanded state according to the embodiment of the present invention;
[27] FIG. 6 is a plan view illustrating the blood vessel stent shown in FIG. 5, when cut in a lengthwise direction and shown in a development view;
[28] FIG. 7 is a perspective view illustrating a main part including a first strut, a second strut, and a third strut of the stent in the expanded state according to the embodiment of the present invention; and
[29] FIG. 8 is a perspective view illustrating the main part including the first strut, the second strut, and the third strut of the stent in the contracted state according to the embodiment of the present invention. Mode for the Invention
[30] Hereinafter, a stent for blood vessels according to the present invention will be described with reference to the accompanying drawings.
[31] FIG. 3 is a perspective view illustrating a blood vessel stent in a contracted state according to an embodiment of the present invention. FIG. 4 is a left-side view of the blood vessel stent of FIG. 3. FIG. 5 is a perspective view illustrating the blood vessel stent in an expanded state according to the embodiment of the present invention. FIG. 6 is a plan view illustrating the blood vessel stent shown in FIG. 5, wherein the blood vessel stent is cut in a lengthwise direction and shown in a development view.
[32] Referring to FIG. 3 to FIG. 6, the stent according to the preferred embodiment of the present invention includes a plurality of ring-shaped hoops 12a to 12d coupled in the length direction of the stent, thereby having a tubular shape. The hoops 12a to 12d can be coupled by connecting the ends of first struts 14 of each of the hoops that face each other. The ends of the first struts 14 are connected through a micro- welding method using a laser, etc.
[33] The struts in each of the hoops 12a to 12d form a ring shape by connecting the struts in a zigzag manner around a circumference of said ring shape.
[34] The struts in the stent includes a plurality of first struts 14 having a predetermined first length Ll, a plurality of second struts 16 having a predetermined second length L2, a pair of which are arranged between two first struts 14, and a plurality of third struts 18 having a predetermined third length L3 for connecting the pairs of the second struts 16. The first to third struts 14, 16 and 18 may be made by cutting a metal plate using laser or twisting a wire. [35] As shown in FIG. 7, a plurality of second struts 16 are bent and inclined inwardly at an inclination angle α (see FIG. 7), so that the second struts 16 are disposed to the inner side of the first struts 16, and the third struts 18 are disposed to the inner side of the second struts 16.
[36] Owing to this structure, when an external force is applied to each of the hoops 12a to 12d in order to contract the stent 10, each of the struts 14, 16, and 18 is plastically deformed, thereby coming into closer contact with each other. Further interference by direct contact between the first struts 14, the second struts 16 and the third struts 18 is not caused.
[37] Accordingly, as shown in FIG. 8, since the first struts 14, the second struts 16 and the third struts 18 can overlap with each other, the circumference of each of the hoops 12a to 12d can be smaller than the sum of the total thickness of the first struts 14, the total thickness of the second struts 16 and the total thickness of the third struts 18 for each of the hoops. Further, the diameter of each of the hoops 12a to 12d, which is equal to the diameter of the stent 10, decreases.
[38] The stent 10 according to the present invention has a structure in which struts 14, 16 and 18 can overlap with each other, and thus although the total thickness of the strut is thicker than that of the conventional one, the diameter of the stent is smaller than that of the conventional one. For reference, the conventional stent has struts that cannot overlap with each other because the struts interfere with each other by facial contact in a contracted state. Accordingly, the circumference of the conventional stent cannot be less than the sum of the total thicknesses of struts.
[39] According to the present invention, since the stent has strong radial force because of the increased thickness of struts, while having a small diameter, it can be easily inserted into a narrow blood vessel, such as a coronary artery.
[40] According to the embodiment of the present invention, the first struts 14 have a predetermined first length Ll, the second struts 16 have a predetermined second length L2 shorter than the first length Ll, and the third struts 18 have a predetermined third length L3 shorter than the second length L2.
[41] Since the first struts 14 act to exert radial force by elasticity and to outwardly press the wall of a blood vessel, they need to have a large area. Accordingly, they are designed to be longer than the other struts 16 and 18. On the other hand, since the second struts 16 and the third struts 18 only act to generate radial force by elasticity, they do not need to be long.
[42] Further, if the second and third struts 16 and 18 are designed to be shorter than the first struts 14, it is possible to prevent interference between ends of the second struts 16 and the third struts 18 of adjacent hoops 12a to 12d when the hoops 12a to 12d are connected to each other. [43] However, the configuration that the second struts 16 and the third struts 18 are shorter than the first struts 14 is not essential to achieve the objects of the present invention. If there is no need to reduce the material cost of the struts, or in the case that there is a method of micro-processing the second struts 16 and the third struts 18 of respective hoops 12a to 12d such that ends of the second struts 16 and the third struts 18 do not interfere with other, the struts 14, 16 and 18 can have the same length.
[44] Further, in case that there is a single hoop in a stent, interference between hoops is not significant.
[45] For reference, according to the above-described embodiment, a stent has a structure in which a plurality of hoops are connected to each other. This type of stent is used to treat a diseased part having a large area. However, in case that a diseased part has a small area, the stent may comprise a single hoop.
[46] In concluding the detailed description, those skilled in the art will appreciate that many variations and modifications can be made to the preferred embodiments without substantially departing from the principles of the present invention. Therefore, it is readily understood that those variations and modifications to the preferred embodiment will be within the scope of the present invention.

Claims

Claims
[1] A stent for blood vessels including a hoop comprising a plurality of struts that form a ring shape by connecting the struts in a zigzag manner around a circumference of said ring shape, thereby having a radial force, wherein the hoop comprises; a plurality of first struts; a plurality of second struts, each pair of the second struts being disposed between two first struts, connecting the two first struts, and bent and inclined inwardly; and a plurality of third struts, each connecting the pairs of the second struts.
[2] The stent according to claim 1, comprising a plurality of hoops, wherein ends of the first struts of each of the hoops are connected to respective ends of the first struts of adjacent hoops to form a tubular shape.
[3] The stent according to claim 2, wherein the second strut has a length shorter than that of the first strut, and the third strut has a length shorter than that of the second strut.
PCT/KR2006/001673 2005-09-23 2006-05-03 Stent for blood vessel WO2007035023A1 (en)

Applications Claiming Priority (2)

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KR1020050088512A KR100667618B1 (en) 2005-09-23 2005-09-23 Stent for vessel with double arrangement strut

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WO2010130788A1 (en) * 2009-05-14 2010-11-18 Angiomed Gmbh & Co. Medizintechnik Kg Stent
CN106859821A (en) * 2017-03-15 2017-06-20 大连理工大学 A kind of biodegradable polymer intravascular stent of injection moulding

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KR101251362B1 (en) 2011-04-06 2013-04-05 (주)시지바이오 Method for manufacturing drug eluting stent

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US6042606A (en) * 1997-09-29 2000-03-28 Cook Incorporated Radially expandable non-axially contracting surgical stent
KR100338213B1 (en) * 2000-01-19 2002-05-24 장양수 A Stent With Improved Flexibility
US20040102834A1 (en) * 2001-02-01 2004-05-27 Ryoji Nakano Stent

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US6042606A (en) * 1997-09-29 2000-03-28 Cook Incorporated Radially expandable non-axially contracting surgical stent
KR100338213B1 (en) * 2000-01-19 2002-05-24 장양수 A Stent With Improved Flexibility
US20040102834A1 (en) * 2001-02-01 2004-05-27 Ryoji Nakano Stent

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WO2010130788A1 (en) * 2009-05-14 2010-11-18 Angiomed Gmbh & Co. Medizintechnik Kg Stent
US8852262B2 (en) 2009-05-14 2014-10-07 C. R. Bard, Inc. Stent
CN106859821A (en) * 2017-03-15 2017-06-20 大连理工大学 A kind of biodegradable polymer intravascular stent of injection moulding

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