WO1999029264A1 - Stainless steel prosthesis to be implanted in a vascular duct using an inflatable balloon - Google Patents

Stainless steel prosthesis to be implanted in a vascular duct using an inflatable balloon Download PDF

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Publication number
WO1999029264A1
WO1999029264A1 PCT/FR1998/002645 FR9802645W WO9929264A1 WO 1999029264 A1 WO1999029264 A1 WO 1999029264A1 FR 9802645 W FR9802645 W FR 9802645W WO 9929264 A1 WO9929264 A1 WO 9929264A1
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WO
WIPO (PCT)
Prior art keywords
stent
stainless steel
endoprosthesis according
thickness
tube
Prior art date
Application number
PCT/FR1998/002645
Other languages
French (fr)
Inventor
Jean-Marie Lefebvre
Original Assignee
Lefebvre Jean Marie
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 Lefebvre Jean Marie filed Critical Lefebvre Jean Marie
Priority to EP98958968A priority Critical patent/EP0961599A1/en
Publication of WO1999029264A1 publication Critical patent/WO1999029264A1/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
    • 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
    • A61F2/82—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

Definitions

  • the present invention relates to the field of stents, more commonly called “stents", which are used in cardiovascular surgery, being implanted in a vascular duct, such as the coronary artery or peripheral arteries, and act as stakes for the vascular duct.
  • the invention more particularly relates to a stent made from a stainless steel tube whose wall has been cut in particular by laser, and which is intended to be implanted in the vascular duct by means of an inflatable balloon.
  • Atheromatous vascular diseases which correspond to narrowing of the arteries
  • balloon dilation techniques called angioplasty.
  • These narrowing of the arteries are caused by an infiltration of the wall and by the formation of an atheroma deposit inside the lumen of the vessel.
  • the balloon is introduced into the artery, and is inflated as a rule with pressures ranging from 4 to 20 Bars, making it possible to crush the atheromatous material and to swell the arterial wall.
  • stent In order to treat and re-stick these intimate tears and reduce restenosis by avoiding secondary recoil, it is currently widely used to implant in the vascular duct, at the area treated by angioplasty, a stent, more commonly called “stent". These stents or stents can be defined as metal supports acting as stakes once they are introduced into the artery at the level of the treated area. In the following description, for the sake of clarity, the stents will be designated by the term "stent".
  • stents those made from coiled wire, those made from a mesh and those made from tubes cut in particular by laser.
  • the invention is in the field of stents made from cut tubes.
  • the stents produced from cut tubes are designed to be deployed by means of an inflatable balloon, during their implantation in the vascular duct.
  • the stents must be crimped onto the balloon, in a so-called rest position, prior to the introduction of the balloon into the vascular duct.
  • the stent Once the stent has been delivered to its implantation zone inside the vascular duct, it is deployed by expansion of the balloon, so as to be brought into contact with the wall of the vascular duct.
  • the prior operation of crimping the stent onto the balloon must be carried out while ensuring that the stent or the balloon is not damaged, while ensuring that the stent is held perfectly in relation to the balloon. It is indeed essential that keeping the stent in position relative to the balloon is sufficient to avoid the risks of displacement of the stent relative to the balloon, during their passage inside the vascular duct to be treated, and in particular at inside the guiding catheter pre-implanted in the vascular duct. Any displacement of the stent may on the one hand obstruct the expansion of the balloon and on the other hand cause a defective opening and positioning of the stent.
  • the stent is sold while already being crimped on a balloon, or the stent is sold separately without being crimped on a balloon.
  • the crimping of the stent is carried out on a new balloon, having a perfectly cylindrical surface of revolution, and is carried out by crushing the stent on the balloon, symmetrically and evenly over the entire length of the stent and over its entire length. circumference.
  • the crimping of the stent is carried out by the surgeon, as a rule on a balloon having already been previously used to dilate the area of the vascular duct to be treated, the crimping is carried out in this case on a balloon which has already deployed, and which therefore has a membrane with asymmetrical folds and which no longer forms a perfect cylinder.
  • a stent must have certain characteristics, the most important of which are radial strength, biocompatibility, flexibility and malleability.
  • a stent made from a cut tube has the advantage of having a greater radial force than the other two types of stents (coiled wire and wire mesh).
  • biocompatibility the material used to make the stent must obviously be biocompatible and the least thrombogenic possible.
  • material used with the exception of a few rare stents made of Platinum, Tantalum or Nitinol, the vast majority of stents are now made of stainless steel.
  • Biocompatibility in particular with regard to the thrombogenic aspect, also depends on the surface condition of the stent, that is to say mainly on the roughness of the surface of the stent. The surface condition must be as smooth as possible.
  • the flexibility of the stent must be sufficient to allow its routing in the vascular conduit, which can be strongly sinuous, and in addition sometimes calcified.
  • An articulated stent is in the form of a succession of rings which on the one hand consist of cells having a determined geometric shape and capable of deploying, and which on the other hand are connected in the longitudinal direction of the stent by connections, so as to be articulated with each other.
  • the malleability of the stent is linked to various factors, including mainly the hardness of the metal used, the thickness of the stent, and the cutting geometry.
  • the malleability of the stent is today considered to be preponderant for the operation of crimping the stent.
  • the more malleable the stent the easier it is to deform it by locally crushing it to fix it on the balloon.
  • the malleable nature of the stent is even more preponderant in the case of a stent intended to be fixed on a used balloon, taking into account the irregularity of the surface of the balloon.
  • the malleability of the stent allows it to match the relief of the irregular surface of the balloon, and thereby obtain a more reliable fixation of the stent on the balloon.
  • the malleability of the stent also influences the flexible nature of the stent. The more malleable the stent, the greater its flexibility.
  • an initial tube for example made of stainless steel, is selected at the start, the thickness of which is equal to the thickness of the final stent, and which also has the hardness required for the stent. final.
  • a laser tube wall wall operation is carried out, so as to give it a determined geometric configuration.
  • the manufacturing operation ends with a cleaning operation by electrolytic polishing, which is carried out so as to round the edges of the stent, to remove cutting burrs and carbonization residues due to laser cutting.
  • the main object of the invention is a stent intended to be implanted in a vascular duct by being deployed under the effect of expansion of a balloon, which once implanted and deployed does not require any additional means for keeping it in place. deployed state and has a sufficient radial force to oppose the elastic retraction of the wall of the vascular duct, and which is obtained by cutting a stainless steel tube.
  • the stent of the invention is characterized by a sufficiently high malleability to obtain an opening of the stent by expansion of the balloon under a pressure less than or equal to 3 bars and in particular under a pressure between 2 bars and 3 bars.
  • tubular stents marketed to date are designed in such a way that they exhibit malleability resulting in an opening under an inflation pressure of the balloon which is at least 5 bars. To date, this malleability has been considered sufficient to meet the crimping and flexibility constraints. In addition, it was considered until now, by the manufacturers of tubular stents, that it was not conceivable to increase the malleability of the existing tubular stents, without the stents collapsing under the effect of elastic retraction of the wall of the vascular duct. It is the merit of the invention to have overcome this technical prejudice, by highlighting that by making a tubular stent cut out of stainless steel which has greater malleability, resulting in an aptitude of the stent to open. at a pressure less than or equal to 3 bars and in particular between 2 bars and 3 bars, a stent was obtained which could have sufficient radial force to reliably oppose the phenomenon of elastic retraction of a vascular conduit.
  • the lower opening pressure of the stent of the invention also provides two important advantages: It makes it possible to obtain better symmetry in the opening of the stent. It contributes to reducing the aggression of the internal wall of the vascular duct by the stent during its opening, and thereby reduces the risk of restenosis by intestinal proliferation.
  • the endoprosthesis of the invention is obtained by carrying out the following operations on a stainless steel tube, having an initial hardness and thickness (e,) greater than the hardness and thickness (e 2 ) sought for the final endoprosthesis: - cutting of the wall of the tube and cleaning by electrolytic polishing, - thermal treatment of hyperhardening, so as to reduce the hardness of the stainless steel, followed by a second electrolytic polishing treatment allowing decrease the initial thickness (e,) of the starting tube while improving its surface condition.
  • FIG. 1 illustrates the main steps of a method of manufacturing a stent according to the invention
  • FIG. 2 to 4 respectively illustrate configurations of a tubular stent according to the invention in the folded state.
  • FIG. 1 illustrates the different stages of manufacturing a tubular stent 1ç_ according to the invention, that is to say a stent which is intended to be implanted in a vascular duct such as a coronary artery or a peripheral artery, after having been crimped onto a balloon, and which is characterized by a malleability sufficiently high to open under an inflation pressure of the balloon of between 2 and 3 bars.
  • Ce 1c stent is made from a tube 1 has departure, stainless steel having a predetermined initial hardness and a roughness index R is given.
  • it is a seamless stainless steel tube for surgical implants meeting the specifications of ISO 5832-1.
  • the initial hardness of the tube 1 measured in Vickers is between 36OHV and 3OOHV; Vickers hardness measurements were carried out under a load of 3OOg and obtained on an average of five impressions.
  • the roughness index R a is approximately 0.8 ⁇ m.
  • the length I of the tube 1 a is approximately 17mm.
  • the thickness e ⁇ and the external diameter d ⁇ of the tube 1 a are preferably substantially equal to 0, 1 mm and 1, 34mm respectively.
  • the thickness e and the external diameter d ⁇ of the tube 1 a are preferably substantially equal to approximately 0.2mm and 30mm respectively.
  • a first step referenced 2 in FIG. 1 laser tube 1 is cut in the usual manner so as to give it a predetermined geometric configuration such as for example one of the configurations illustrated in FIGS. 2 to 4.
  • the cut tube 1b from step 2 undergoes in a second step 3 cleaning by electrolytic polishing.
  • This step 3 is known per se and consists in removing from the surface of the tube 1 b the cutting burrs and the carbonization residues due to the laser cutting, by electrochemical means, by applying a given electric current density between the tube 1 a and a liquid medium called an electrolyte.
  • the tube undergoes a heat treatment of hyper quenching 4 having the function of reducing the hardness of the stainless steel.
  • this hyper-quenching heat treatment consists of a first step of cooking the tube 1b in a vacuum oven, followed by a second step of rapid cooling of the tube 1b using liquid nitrogen. . More particularly, during the cooking step, the tube is brought for a short time (about 1 minute) to a temperature of 1040 ° C .; in the aforementioned preferred embodiment, the Vickers hardness of the stainless steel dropped to a value between 2OOHV and 24OHV.
  • the tube undergoes in a step 5, a second electrolytic polishing treatment, similar in its implementation to treatment 3, but with operating conditions, and in particular a treatment duration, calibrated to obtain a reduction in thickness of the tube within a predetermined range, and preferably between 0.04mm and 0.02mm.
  • a second electrolytic polishing treatment similar in its implementation to treatment 3, but with operating conditions, and in particular a treatment duration, calibrated to obtain a reduction in thickness of the tube within a predetermined range, and preferably between 0.04mm and 0.02mm.
  • the thickness e 2 of the tube 1 c obtained at the outlet of step 4 was between 0.06mm and 0.08mm, and was equal to average 0.067mm; for a stent intended to be implanted in a peripheral artery, the thickness e 2 of the tube 1c obtained at the outlet of step 4 was between 0.16mm and 0.18mm, and was worth on average 0.17mm.
  • the roughness index R a of the stent 1ç obtained at the end of the process, under the effect of the double electropolishing of steps 3 and 4 dropped to a value between 0.1 ⁇ m and 0.4 ⁇ m.
  • the roughness measurement R a of the stent 1c and of the initial starting tube 1a was carried out using a TAYLOR-HOBSON surface condition measuring device (TALYSUL F10 model) and a standard wafer of roughness reference BA5 ETRUG 301, the probe of the measuring device had a radius of O, OO25mm; the measuring force was 1 OOmN, the probing length was between 1 mm and 6mm.
  • the measurements were taken on the generatrices of the tube in the longitudinal direction at the level of the middle zone of the tubular stent.
  • the laser cutting (step 2) of the starting tube 1a is carried out so as to give the wall of the tube a geometrical configuration in accordance with one of the three variants of FIGS. 2 to 4 which will be described below and which represent the geometric structure of the stent in the resting state, that is to say of the unexpanded stent.
  • the stent obtained could be implanted in a vascular conduit, after having been deployed by means of a balloon inflated under low pressure, between 2 bars and 3 bars. Once implanted, the stent exerted on the wall of the vascular duct a sufficient radial force to oppose the elastic retraction of the wall, without the need for a device additional to maintain the stent in the deployed state.
  • the tubular stent 1ç is an articulated stent, consisting of a succession of annular segments 6, of width i 1 (connected two by two in the direction of l longitudinal axis 8 of the stent, by short connections 7 of length ⁇ 2.
  • these connections 7 have the shape substantially of an S with a central inflection point 7a.
  • Each articulation zone 6b is constituted by a segment oriented substantially perpendicular to the longitudinal axis 8 of the stent.
  • the connections 7 connect two adjacent annular segments 6 by means of their respective articulation zones 6b. More particularly, in FIG. 2, the annular segments 6 are oriented successively at opposite angles, and the articulation zones
  • Each articulation zone 6b of an annular segment 6 is connected to two arms 6a and to a connection 7 via respectively three pivots P- ,, P 2 , and P 3 allowing the deformation of the stent 1ç_ during l expansion of the balloon on which the stent is mounted.
  • P- , P 2 , and P 3 allowing the deformation of the stent 1ç_ during l expansion of the balloon on which the stent is mounted.
  • the pivot P 2 corresponds to the articulation of an arm 6a making an angle A, with respect to the articulation zone 6b; in the example illustrated, the angle A is greater than 90 ° and is more particularly about 120 °; the pivot P ⁇ corresponds to the articulation of an arm 6a making an angle B with the articulation zone 6b; this angle B is less than 90 ° and is worth more particularly around 30 ° ; the pivot P 3 corresponds to the junction of an articulation zone 6b with a connection 7.
  • each arm 6a makes a substantially angle of 45 ° relative to the longitudinal axis 8 of the stent.
  • Each arm 6a of angle A opens at an angle ⁇ , of approximately 15 °
  • each arm 6a of angle B opens at an angle a 2 of approximately 75 °.
  • the width ⁇ of each segment 6 is preferably between 1 mm and 1.5 mm. More particularly, for a stent intended to be implanted in a coronary artery, this width L is preferably between 1 mm and 1.2 mm; for a stent intended to be implanted in a peripheral artery, this width 1 is preferably of the order of 1.4 mm.
  • the length [ 2 of the connections 7 is approximately 0.5 mm.
  • the thickness E p of the annular segments 6 is equal to the thickness of the connections 7 and is substantially equal to 0.1 mm.
  • FIG. 3 differs from that of FIG. 2 by the geometry of the articulation zones 6b of the annular segments 6.
  • Each articulation zone 6b_ consists of two curved segments S, and S 2 forming between them an angle ⁇ being substantially 90 °.
  • the two angles A and B of the pivots P, and P 2 are advantageously greater than 90 °, which facilitates the opening of the stent, compared to the stent of FIG. 2 for which only one of the two angles, in this case the angle A constitutes an obtuse angle.
  • the angles a and ⁇ are worth approximately 135 °.
  • FIG. 4 differs from that of FIG. 3, on the one hand in that the arms 6a of the annular segments 6 are oriented substantially parallel to the longitudinal axis 8 of the stent, and on the other hand in that that the connections 7 have a different shape and are oriented in a transverse direction with an angle y relative to the longitudinal axis 8 of the stent.
  • each arm 6a opening at substantially the same angle, i.e. about 45 °.
  • connections 7 transversely to the longitudinal axis 8 of the stent makes it possible to produce connections 7 whose length is greater, which allows better compensation for the reduction in the length of the stent when it is opened. More particularly, in the example of FIG. 4, the connections 7 consist of a wavy segment with four inflection points 7a for their elongation. This particular structure makes it possible to have a greater length reserve compared to the connections 7 of FIGS. 2 and 3.

Abstract

The invention concerns a prosthesis (1c) designed to be implanted in a vascular duct being unfolded by the effect of an expanding balloon, and obtained by cutting a stainless steel tube. It has sufficient malleability to be opened by the expansion of a balloon under pressure not more than 3 bars and particularly pressure between 2.5 bars and 3 bars. Preferably, the prosthesis is obtained by carrying out the following operations on a stainless steel tube (1a), having initial hardness and thickness (e1) greater than the hardness and thickness (e1) required for the final prosthesis: cutting the tube (1a) wall and cleaning it by electropolishing; rapid quenching heat treatment (4), so as to reduce the stainless steel hardness, followed by a second electropolishing treatment (5) for reducing the original tube (1a) initial thickness (e1) while improving its surface state.

Description

ENDOPROTHESE EN ACIER INOXYDABLE DESTINEE A ETRE IMPLANTEE DANS UN CONDUIT VASCULAIRE AU MOYEN D'UN STAINLESS STEEL STENT TO BE IMPLANTED IN A VASCULAR CONDUIT USING A
BALLONNET GONFLABLEINFLATABLE BALLOON
La présente invention concerne le domaine des endoprothèses, plus communément appelées "stents", qui sont utilisées en chirurgie cardio-vasculaire, en étant implantées dans un conduit vasculaire, type artère coronaire ou artères périphériques, et font office de tuteurs pour le conduit vasculaire. L'invention a plus particulièrement pour objet un stent réalisé à partir d'un tube en acier inoxydable dont la paroi a été découpée notamment par laser, et qui est destiné à être implanté dans le conduit vasculaire au moyen d'un ballonnet gonflable.The present invention relates to the field of stents, more commonly called "stents", which are used in cardiovascular surgery, being implanted in a vascular duct, such as the coronary artery or peripheral arteries, and act as stakes for the vascular duct. The invention more particularly relates to a stent made from a stainless steel tube whose wall has been cut in particular by laser, and which is intended to be implanted in the vascular duct by means of an inflatable balloon.
Depuis une dizaine d'années, il est connu de traiter les maladies athéromateuses vasculaires, qui correspondent à des rétrécissements des artères, par des techniques de dilatation par ballonnet, appelées angioplastie. Ces rétrécissements des artères sont provoqués par une infiltration de la paroi et par la formation d'un dépôt d'athérome à l'intérieur de la lumière du vaisseau. En angioplastie, le ballonnet est introduit dans l'artère, et est gonflé en règle générale avec des pressions allant de 4 à 20 Bars, permettant d'écraser le matériel athéromateux et de boursoufler la paroi artérielle.For ten years, it has been known to treat atheromatous vascular diseases, which correspond to narrowing of the arteries, by balloon dilation techniques, called angioplasty. These narrowing of the arteries are caused by an infiltration of the wall and by the formation of an atheroma deposit inside the lumen of the vessel. In angioplasty, the balloon is introduced into the artery, and is inflated as a rule with pressures ranging from 4 to 20 Bars, making it possible to crush the atheromatous material and to swell the arterial wall.
Les techniques d'angioplastie couramment utilisées souffrent malheureusement d'un taux de récidive important d'environ 30%. Ces récidives sont dues à un double phénomène : d'une part une rétractation élastique, communément appelée "recoil secondaire", de la zone dilatée et d'autre part une réaction inflammatoire, appelée "prolifération intimale", de la partie interne de la paroi du vaisseau. En outre, un certain nombre d'angioplasties peuvent se compliquer d'une déchirure intimale encore appelée "flap" de la paroi intérieure de l'artère, pouvant entraîner une obstruction aiguë de l'artère. Cette thrombose aiguë peut être responsable d'accidents extrêmement graves (infarctus, décès,...). Dans le but de traiter et recoller ces déchirures intimales et de diminuer la resténose en évitant le recoil secondaire, il est à ce jour largement répandu d'implanter dans le conduit vasculaire, au niveau de la zone traitée par angioplastie, une endoprothèse, plus communément appelée "stent". Ces endoprothèses ou stents peuvent se définir comme des supports métalliques agissant comme tuteurs une fois qu'ils sont introduits à l'intérieur de l'artère au niveau de la zone traitée. Dans la suite de la description, par souci de clarté, les endoprothèses seront désignés par le terme "stent".The commonly used angioplasty techniques unfortunately suffer from a significant recurrence rate of around 30%. These recurrences are due to a double phenomenon: on the one hand an elastic retraction, commonly called "secondary recoil", of the dilated zone and on the other hand an inflammatory reaction, called "intimal proliferation", of the internal part of the wall of the vessel. In addition, a number of angioplasties can be complicated by an intimal tear also called a "flap" of the inner wall of the artery, which can lead to acute obstruction of the artery. This acute thrombosis can be responsible for extremely serious accidents (infarction, death, ...). In order to treat and re-stick these intimate tears and reduce restenosis by avoiding secondary recoil, it is currently widely used to implant in the vascular duct, at the area treated by angioplasty, a stent, more commonly called "stent". These stents or stents can be defined as metal supports acting as stakes once they are introduced into the artery at the level of the treated area. In the following description, for the sake of clarity, the stents will be designated by the term "stent".
On distingue à ce jour trois types de stents : ceux fabriqués à partir d'un fil enroulé, ceux réalisés à partir d'un grillage et ceux réalisés à partir de tubes découpés notamment par laser. L'invention se situe dans le domaine des stents réalisés à partir de tubes découpés.To date, there are three types of stents: those made from coiled wire, those made from a mesh and those made from tubes cut in particular by laser. The invention is in the field of stents made from cut tubes.
Les stents réalisés à partir de tubes découpés sont conçus pour être déployés au moyen d'un ballonnet gonflable, lors de leur implantation dans le conduit vasculaire. A cet effet, les stents doivent être sertis sur le ballonnet, dans une position dite de repos, préalablement à l'introduction du ballonnet dans le conduit vasculaire. Une fois le stent acheminé jusqu'à sa zone d'implantation à l'intérieur du conduit vasculaire, il est déployé par expansion du ballonnet, en sorte d'être amené au contact de la paroi du conduit vasculaire.The stents produced from cut tubes are designed to be deployed by means of an inflatable balloon, during their implantation in the vascular duct. For this purpose, the stents must be crimped onto the balloon, in a so-called rest position, prior to the introduction of the balloon into the vascular duct. Once the stent has been delivered to its implantation zone inside the vascular duct, it is deployed by expansion of the balloon, so as to be brought into contact with the wall of the vascular duct.
L'opération préalable de sertissage du stent sur le ballonnet doit être réalisée en s'assurant que l'on n'abîme pas le stent ou le ballonnet, tout en veillant à obtenir une tenue parfaite du stent par rapport au ballonnet. Il est en effet primordial que le maintien en position du stent par rapport au ballonnet soit suffisant pour éviter les risques de déplacement du stent par rapport au ballonnet, lors de leur cheminement à l'intérieur du conduit vasculaire à traiter, et en particulier à l'intérieur du cathéter de guidage pré-implanté dans le conduit vasculaire. Tout déplacement du stent peut d'une part faire obstacle à l'expansion du ballonnet et d'autre part occasionner une ouverture et une mise en place défectueuses du stent. Au regard de l'opération de sertissage, deux cas de figures peuvent en pratique se présenter : le stent est vendu en étant déjà serti sur un ballonnet, ou le stent est vendu séparément sans être serti sur un ballonnet. Dans le premier cas, le sertissage du stent est effectué sur un ballonnet neuf, ayant une surface de révolution parfaitement cylindrique, et est réalisé en écrasant le stent sur le ballonnet, de manière symétrique et régulière sur toute la longueur du stent et sur toute sa circonférence. Dans le second cas, le sertissage du stent est réalisé par le chirurgien, en règle général sur un ballonnet ayant déjà été préalablement utilisé pour dilater la zone du conduit vasculaire devant être traitée, le sertissage s'effectue dans ce cas sur un ballonnet qui a déjà été déployé, et qui de ce fait comporte une membrane présentant des plissements asymétriques et qui ne forme plus un cylindre parfait.The prior operation of crimping the stent onto the balloon must be carried out while ensuring that the stent or the balloon is not damaged, while ensuring that the stent is held perfectly in relation to the balloon. It is indeed essential that keeping the stent in position relative to the balloon is sufficient to avoid the risks of displacement of the stent relative to the balloon, during their passage inside the vascular duct to be treated, and in particular at inside the guiding catheter pre-implanted in the vascular duct. Any displacement of the stent may on the one hand obstruct the expansion of the balloon and on the other hand cause a defective opening and positioning of the stent. With regard to the crimping operation, two cases of figures can arise in practice: the stent is sold while already being crimped on a balloon, or the stent is sold separately without being crimped on a balloon. In the first case, the crimping of the stent is carried out on a new balloon, having a perfectly cylindrical surface of revolution, and is carried out by crushing the stent on the balloon, symmetrically and evenly over the entire length of the stent and over its entire length. circumference. In the second case, the crimping of the stent is carried out by the surgeon, as a rule on a balloon having already been previously used to dilate the area of the vascular duct to be treated, the crimping is carried out in this case on a balloon which has already deployed, and which therefore has a membrane with asymmetrical folds and which no longer forms a perfect cylinder.
Un stent doit présenter certaines caractéristiques dont les plus importantes sont la force radiale, la biocompatibilité, la flexibilité et la malléabilité.A stent must have certain characteristics, the most important of which are radial strength, biocompatibility, flexibility and malleability.
La force radiale du stent doit être suffisante pour s'opposer à la rétraction élastique de la paroi du conduit vasculaire. Un stent fabriqué à partir d'un tube découpé présente l'avantage de présenter une force radiale plus importante que les deux autres types de stents ( fil enroulé et grillage).The radial force of the stent must be sufficient to oppose the elastic retraction of the wall of the vascular duct. A stent made from a cut tube has the advantage of having a greater radial force than the other two types of stents (coiled wire and wire mesh).
S'agissant de la biocompatibilité, le matériau utilisé pour fabriquer le stent doit évidemment être biocompatible et le moins thrombogène possible. S'agissant du matériau utilisé, à l'exception de quelques rares stents en Platinium, Tantalum ou Nitinol, la grande majorité des stents est aujourd'hui réalisée en acier inoxydable. La biocompatibilité, au regard notamment de l'aspect thrombogène, dépend également de l'état de surface du stent, c'est-à-dire principalement de la rugosité de la surface du stent. L'état de surface doit être le plus lisse possible. La flexibilité du stent doit être suffisante pour permettre son acheminement dans le conduit vasculaire, qui peut être fortement sinueux, et en outre parfois calcifié. Pour améliorer la flexibilité des stents, il est largement répandu à ce jour de réaliser des stents tubulaire articulés, tels que ceux décrits par exemple dans la demande de brevet internationale WO 96/33671 . Un stent articulé se présente sous la forme d'une succession d'anneaux qui d'une part sont constitués de cellules ayant une forme géométrique déterminée et aptes à se déployer, et qui d'autre part sont reliés dans la direction longitudinale du stent par des connections, en sorte d'être articulés les uns par rapport aux autres. La malléabilité du stent est liée à différents facteurs, dont principalement la dureté du métal utilisé, l'épaisseur du stent, et la géométrie de découpe. La malléabilité du stent est à ce jour considérée comme prépondérante pour l'opération de sertissage du stent. Plus le stent est malléable, et plus il est facile de le déformer en l'écrasant localement pour le fixer sur le ballonnet. Le caractère malléable du stent est encore plus prépondérant dans le cas d'un stent destiné à être fixé sur un ballonnet usagé, compte-tenu de l'irrégularité de la surface du ballonnet. La malléabilité du stent permet de lui faire épouser le relief de la surface irrégulière du ballonnet, et par là-même d'obtenir un fixation plus fiable du stent sur le ballonnet. Enfin, il est connu que la malléabilité du stent influe également sur le caractère flexible du stent. Plus le stent est malléable, et plus sa flexibilité est importante.With regard to biocompatibility, the material used to make the stent must obviously be biocompatible and the least thrombogenic possible. Regarding the material used, with the exception of a few rare stents made of Platinum, Tantalum or Nitinol, the vast majority of stents are now made of stainless steel. Biocompatibility, in particular with regard to the thrombogenic aspect, also depends on the surface condition of the stent, that is to say mainly on the roughness of the surface of the stent. The surface condition must be as smooth as possible. The flexibility of the stent must be sufficient to allow its routing in the vascular conduit, which can be strongly sinuous, and in addition sometimes calcified. To improve the flexibility of stents, it is widely used today to produce articulated tubular stents, such as those described for example in international patent application WO 96/33671. An articulated stent is in the form of a succession of rings which on the one hand consist of cells having a determined geometric shape and capable of deploying, and which on the other hand are connected in the longitudinal direction of the stent by connections, so as to be articulated with each other. The malleability of the stent is linked to various factors, including mainly the hardness of the metal used, the thickness of the stent, and the cutting geometry. The malleability of the stent is today considered to be preponderant for the operation of crimping the stent. The more malleable the stent, the easier it is to deform it by locally crushing it to fix it on the balloon. The malleable nature of the stent is even more preponderant in the case of a stent intended to be fixed on a used balloon, taking into account the irregularity of the surface of the balloon. The malleability of the stent allows it to match the relief of the irregular surface of the balloon, and thereby obtain a more reliable fixation of the stent on the balloon. Finally, it is known that the malleability of the stent also influences the flexible nature of the stent. The more malleable the stent, the greater its flexibility.
A ce jour, pour fabriquer un stent tubulaire métallique, on sélectionne au départ un tube initial, par exemple en acier inoxydable, dont l'épaisseur est égale à l'épaisseur du stent final, et qui présente en outre la dureté requise pour le stent final. Sur ce tube de départ, on réalise une opération de découpe de la paroi du tube au laser, en sorte de lui donner une configuration géométrique déterminée. L'opération de fabrication se termine par une opération de nettoyage par polissage électrolytique, qui est réalisée en sorte d'arrondir les arêtes du stent, de supprimer les bavures de découpe et les résidus de la carbonisation dûs à la découpe laser. L'invention a pour principal objet un stent destiné à être implanté dans un conduit vasculaire en étant déployé sous l'effet d'expansion d'un ballonnet, qui une fois implanté et déployé ne nécessite pas de moyen supplémentaire pour son maintien à l'état déployé et présente une force radiale suffisante pour s'opposer à la rétractation élastique de la paroi du conduit vasculaire, et qui est obtenu par découpe d'un tube en acier inoxydable. Le stent de l'invention se caractérise par une malléabilité suffisamment importante pour obtenir une ouverture du stent par expansion du ballonnet sous une pression inférieure ou égale à 3 bars et en particulier sous une pression comprise entre 2 bars et 3 bars.To date, to manufacture a metallic tubular stent, an initial tube, for example made of stainless steel, is selected at the start, the thickness of which is equal to the thickness of the final stent, and which also has the hardness required for the stent. final. On this starting tube, a laser tube wall wall operation is carried out, so as to give it a determined geometric configuration. The manufacturing operation ends with a cleaning operation by electrolytic polishing, which is carried out so as to round the edges of the stent, to remove cutting burrs and carbonization residues due to laser cutting. The main object of the invention is a stent intended to be implanted in a vascular duct by being deployed under the effect of expansion of a balloon, which once implanted and deployed does not require any additional means for keeping it in place. deployed state and has a sufficient radial force to oppose the elastic retraction of the wall of the vascular duct, and which is obtained by cutting a stainless steel tube. The stent of the invention is characterized by a sufficiently high malleability to obtain an opening of the stent by expansion of the balloon under a pressure less than or equal to 3 bars and in particular under a pressure between 2 bars and 3 bars.
Les stents tubulaires commercialisés à ce jour sont conçus de telle sorte qu'ils présentent une malléabilité se traduisant par une ouverture sous une pression de gonflage du ballonnet qui est au minimum de 5 bars. On a jusqu'à ce jour considéré que cette malléabilité était suffisante pour répondre aux contraintes de sertissage et de flexibilité. En outre, il était considéré jusqu'à ce jour, par les fabricants de stents tubulaires, qu'il n'était pas envisageable d'augmenter la malléabilité des stents tubulaires existants, sans que les stents ne s'affaissent sous l'effet de rétraction élastique de la paroi du conduit vasculaire. C'est le mérite de l'invention d'avoir vaincu ce préjugé technique, en mettant en évidence qu'en réalisant un stent tubulaire découpé en acier inoxydable qui présente une malléabilité plus importante, se traduisant par une aptitude du stent à l'ouverture à une pression inférieure ou égale à 3 bars et en particulier comprise entre 2 bars et 3 bars, on obtenait un stent pouvant présenter une force radiale suffisante pour s'opposer de manière fiable au phénomène de rétraction élastique d'un conduit vasculaire.The tubular stents marketed to date are designed in such a way that they exhibit malleability resulting in an opening under an inflation pressure of the balloon which is at least 5 bars. To date, this malleability has been considered sufficient to meet the crimping and flexibility constraints. In addition, it was considered until now, by the manufacturers of tubular stents, that it was not conceivable to increase the malleability of the existing tubular stents, without the stents collapsing under the effect of elastic retraction of the wall of the vascular duct. It is the merit of the invention to have overcome this technical prejudice, by highlighting that by making a tubular stent cut out of stainless steel which has greater malleability, resulting in an aptitude of the stent to open. at a pressure less than or equal to 3 bars and in particular between 2 bars and 3 bars, a stent was obtained which could have sufficient radial force to reliably oppose the phenomenon of elastic retraction of a vascular conduit.
La plus faible pression d'ouverture du stent de l'invention procure en outre deux avantages importants : Elle permet d'obtenir une meilleure symétrie dans l'ouverture du stent. Elle contribue à diminuer l'agression de la paroi interne du conduit vasculaire par le stent lors de son ouverture, et par là-même diminue les risques de resténose par prolifération intimale.The lower opening pressure of the stent of the invention also provides two important advantages: It makes it possible to obtain better symmetry in the opening of the stent. It contributes to reducing the aggression of the internal wall of the vascular duct by the stent during its opening, and thereby reduces the risk of restenosis by intestinal proliferation.
On a certes déjà proposé à ce jour dans le brevet US.5, 190,058 un stent réalisé dans un matériau résilient, et par exemple en acier inoxydable, pouvant être déployé au moyen d'un ballonnet gonflé sous une pression d'au moins une atmosphère (1 ,01 bars). Cependant d'une part il s'agit d'un stent formé de filaments entrelacés et non pas d'un stent obtenu par découpe d'un tube en acier inoxydable ; d'autre part le stent décrit dans cette publication est un stent temporaire, qui lorsqu'il est en acier inoxydable, nécessite un dispositif additionnel (référencé 35 sur les figures de cette publication) qui permet de verrouiller le stent dans sa position déployée en lui appliquant une force radiale suffisante pour éviter la rétractation élastique de la paroi du conduit dans lequel le stent est mis en place temporairement. Plus particulièrement, l'endoprothèse de l'invention est obtenue en réalisant les opérations ci-après sur un tube en acier inoxydable, présentant une dureté et une épaisseur (e,) initiales supérieures à la dureté et à l'épaisseur (e2) recherchées pour l'endoprothèse finale : - découpe de la paroi du tube et nettoyage par polissage électrolytique, - traitement thermique d'hypertrempe, en sorte de diminuer la dureté de l'acier inoxydable, suivi d'un deuxième traitement de polissage électrolytique permettant de diminuer l'épaisseur initiale (e,) du tube de départ tout en améliorant son état de surface.It has certainly already been proposed to date in patent US.5, 190.058 a stent made of a resilient material, and for example of stainless steel, which can be deployed by means of a balloon inflated under a pressure of at least one atmosphere (1.01 bars). However on the one hand it is a stent formed of interlaced filaments and not a stent obtained by cutting a stainless steel tube; on the other hand the stent described in this publication is a temporary stent, which when it is made of stainless steel, requires an additional device (referenced 35 in the figures of this publication) which makes it possible to lock the stent in its deployed position in it applying sufficient radial force to avoid elastic retraction of the wall of the conduit in which the stent is temporarily placed. More particularly, the endoprosthesis of the invention is obtained by carrying out the following operations on a stainless steel tube, having an initial hardness and thickness (e,) greater than the hardness and thickness (e 2 ) sought for the final endoprosthesis: - cutting of the wall of the tube and cleaning by electrolytic polishing, - thermal treatment of hyperhardening, so as to reduce the hardness of the stainless steel, followed by a second electrolytic polishing treatment allowing decrease the initial thickness (e,) of the starting tube while improving its surface condition.
Il est avantageux de partir d'un tube initial présentant une dureté élevée supérieure à la dureté finale recherchée, car plus l'acier inoxydable est dur, et plus sa rugosité est faible. Il est donc plus facile d'obtenir un stent présentant un meilleur état de surface. La diminution d'épaisseur liée à un double polissage électrolytique permet d'augmenter la malléabilité et la flexibilité du stent, comparativement à un stent réalisé selon le procédé connu précité, à partir d'un tube de même épaisseur initiale. Le double polissage électrolytique permet en outre d'améliorer sensiblement l'état de surface final du stent.It is advantageous to start from an initial tube having a high hardness greater than the desired final hardness, because the harder the stainless steel, the lower its roughness. It is therefore easier to obtain a stent having a better surface condition. The reduction in thickness linked to a double electrolytic polishing makes it possible to increase the malleability and the flexibility of the stent, compared to a stent produced according to the aforementioned known method, from a tube of the same initial thickness. The double electropolishing also improves substantially the final surface condition of the stent.
D'autres caractéristiques et avantages de l'invention apparaîtront plus clairement à la lecture de la description ci-après d'un exemple de fabrication d'un stent de l'invention et de plusieurs configurations géométriques possibles d'un stent tubulaire selon l'invention, laquelle description est donnée à titre d'exemple non limitatif et en référence au dessin annexé sur lequel :Other characteristics and advantages of the invention will appear more clearly on reading the following description of an example of manufacturing a stent of the invention and of several possible geometric configurations of a tubular stent according to the invention, which description is given by way of nonlimiting example and with reference to the appended drawing in which:
- la figure 1 illustre les étapes principales d'un procédé de fabrication d'un stent conforme à l'invention, - et les figures 2 à 4 illustrent respectivement des configurations d'un stent tubulaire selon l'invention à l'état replié.- Figure 1 illustrates the main steps of a method of manufacturing a stent according to the invention, - and Figures 2 to 4 respectively illustrate configurations of a tubular stent according to the invention in the folded state.
La figure 1 illustre les différentes étapes de fabrication d'un stent tubulaire 1ç_ conforme à l'invention, c'est-à-dire d'un stent qui est destiné à être implanté dans un conduit vasculaire tel qu'une artère coronaire ou une artère périphérique, après avoir été serti sur un ballonnet, et qui se caractérise par une malléabilité suffisamment importante pour s'ouvrir sous une pression de gonflage du ballonnet comprise entre 2 et 3 bars. Dans l'exemple particulier qui va à présent être décrit, ce stent 1ç est réalisé à partir d'un tube 1 a de départ, en acier inoxydable ayant une dureté initiale prédéterminée et un indice de rugosité Ra donné. De préférence, il s'agit d'un tube en acier inoxydable sans soudure pour implants chirurgicaux répondant aux spécifications de la norme ISO 5832-1 . La dureté initiale du tube 1 a mesurée en Vickers est comprise entre 36OHV et 3OOHV ; les mesures de dureté Vickers étaient réalisées sous une charge de 3OOg et obtenues sur une moyenne de cinq empreintes. L'indice de rugosité Ra vaut environ 0,8μm. La longueur I du tube 1 a vaut environ 17mm. S'agissant d'un stent 1ç destiné à être implanté dans une artère coronaire, l'épaisseur e^ et le diamètre externe d^ du tube 1 a sont de préférence sensiblement égaux respectivement à 0, 1 mm et à 1 ,34mm. S'agissant d'un stent 1ç destiné à être implanté dans une artère périphérique de plus grand diamètre, l'épaisseur e et le diamètre externe d^ du tube 1 a sont de préférence sensiblement égaux respectivement environ à 0,2mm et 30mm.FIG. 1 illustrates the different stages of manufacturing a tubular stent 1ç_ according to the invention, that is to say a stent which is intended to be implanted in a vascular duct such as a coronary artery or a peripheral artery, after having been crimped onto a balloon, and which is characterized by a malleability sufficiently high to open under an inflation pressure of the balloon of between 2 and 3 bars. In the particular example which will now be described, Ce 1c stent is made from a tube 1 has departure, stainless steel having a predetermined initial hardness and a roughness index R is given. Preferably, it is a seamless stainless steel tube for surgical implants meeting the specifications of ISO 5832-1. The initial hardness of the tube 1 measured in Vickers is between 36OHV and 3OOHV; Vickers hardness measurements were carried out under a load of 3OOg and obtained on an average of five impressions. The roughness index R a is approximately 0.8 μm. The length I of the tube 1 a is approximately 17mm. In the case of a stent 1c intended to be implanted in a coronary artery, the thickness e ^ and the external diameter d ^ of the tube 1 a are preferably substantially equal to 0, 1 mm and 1, 34mm respectively. In the case of a stent 1c intended to be implanted in a peripheral artery of larger diameter, the thickness e and the external diameter d ^ of the tube 1 a are preferably substantially equal to approximately 0.2mm and 30mm respectively.
Dans une première étape référencée 2 sur la figure 1 , on procède de manière usuelle à une découpe au laser du tube 1 a en sorte de lui donner une configuration géométrique prédéterminée telle que par exemple l'une des configurations illustrées aux figures 2 à 4. Le tube découpé 1 b issu de l'étape 2 subit dans une deuxième étape 3 un nettoyage par polissage électrolytique. Cette étape 3 est en soi connue et consiste à enlever de la surface du tube 1 b les bavures de découpe et les résidus de la carbonisation dus à la découpe laser, par voie électrochimique, en appliquant une densité de courant électrique donnée entre le tube 1 a et un milieu liquide appelé électrolyte. Il revient à l'homme du métier d'adapter les conditions opératoires (choix de l'électrolyte, densité de courant appliquée, durée du traitement...) au type particulier de tube 1 b issu de l'étape 2 pour obtenir à l'issue de l'étape 3 un tube propre dont la surface ne comporte plus de bavure et a été débarrassée de ses impuretés.In a first step referenced 2 in FIG. 1, laser tube 1 is cut in the usual manner so as to give it a predetermined geometric configuration such as for example one of the configurations illustrated in FIGS. 2 to 4. The cut tube 1b from step 2 undergoes in a second step 3 cleaning by electrolytic polishing. This step 3 is known per se and consists in removing from the surface of the tube 1 b the cutting burrs and the carbonization residues due to the laser cutting, by electrochemical means, by applying a given electric current density between the tube 1 a and a liquid medium called an electrolyte. It is up to the person skilled in the art to adapt the operating conditions (choice of electrolyte, current density applied, duration of treatment, etc.) to the particular type of tube 1 b from step 2 to obtain the 'from step 3 a clean tube whose surface no longer has a burr and has been freed of its impurities.
A l'issue de la première étape de nettoyage par polissage électrolytique, le tube subit un traitement thermique d'hypertrempe 4 ayant pour fonction de diminuer la dureté de l'acier inoxydable. Dans un exemple précis de réalisation, ce traitement thermique d'hypertrempe est constitué par une première étape de cuisson du tube 1 b dans un four sous vide, suivie d'une seconde étape de refroidissement rapide du tube 1 b au moyen d'azote liquide. Plus particulièrement, au cours de l'étape de cuisson, le tube est porté pendant une courte durée (environ 1 minute) à une température de 1 O4O °C ; dans l'exemple préféré de réalisation précité, la dureté Vickers de l'acier inoxydable chutait à une valeur comprise entre 2OOHV et 24OHV.At the end of the first cleaning step by electrolytic polishing, the tube undergoes a heat treatment of hyper quenching 4 having the function of reducing the hardness of the stainless steel. In a specific exemplary embodiment, this hyper-quenching heat treatment consists of a first step of cooking the tube 1b in a vacuum oven, followed by a second step of rapid cooling of the tube 1b using liquid nitrogen. . More particularly, during the cooking step, the tube is brought for a short time (about 1 minute) to a temperature of 1040 ° C .; in the aforementioned preferred embodiment, the Vickers hardness of the stainless steel dropped to a value between 2OOHV and 24OHV.
A l'issue de l'étape d'hypertrempe, le tube subit dans une étape 5, un deuxième traitement de polissage électrolytique, similaire dans sa mise en oeuvre au traitement 3, mais avec des conditions opératoires, et notamment une durée de traitement, calibrées pour obtenir une réduction d'épaisseur du tube dans une fourchette prédéterminée, et de préférence comprise entre 0,04mm et 0,02mm. Dans un exemple précis de réalisation, pour un stent destiné à être implanté dans une artère coronaire, l'épaisseur e2 du tube 1 c obtenu en sortie de l'étape 4 était comprise entre 0,06mm et 0,08mm, et valait en moyenne 0,067mm ; pour un stent destiné à être implanté dans une artère périphérique, l'épaisseur e2 du tube 1ç obtenu en sortie de l'étape 4 était comprise entre 0, 16mm et 0, 18mm, et valait en moyenne 0, 17mm. Pour les deux types de stents précités, l'indice de rugosité Ra du stent 1ç obtenu en fin de procédé, sous l'effet du double polissage électrolytique des étapes 3 et 4 chutait à une valeur comprise entre O,1μm et O,4μm, et valait en moyenne O,2μm. La mesure de la rugosité Ra du stent 1ç et du tube initial de départ 1 a était réalisée à l'aide d'un appareil de mesure d'état de surface TAYLOR-HOBSON (modèle TALYSUL F10) et d'une plaquette étalon de référence de rugosité BA5 ETRUG 301 , le palpeur de l'appareil de mesure avait un rayon de O,OO25mm ; la force de mesure était de 1 OOmN, la longueur de palpage était comprise entre 1 mm et 6mm. Les mesures étaient effectuées sur les génératrices du tube dans le sens longitudinal au niveau de la zone médiane du stent tubulaire.At the end of the hyper quenching step, the tube undergoes in a step 5, a second electrolytic polishing treatment, similar in its implementation to treatment 3, but with operating conditions, and in particular a treatment duration, calibrated to obtain a reduction in thickness of the tube within a predetermined range, and preferably between 0.04mm and 0.02mm. In a specific embodiment, for a stent intended to be implanted in a coronary artery, the thickness e 2 of the tube 1 c obtained at the outlet of step 4 was between 0.06mm and 0.08mm, and was equal to average 0.067mm; for a stent intended to be implanted in a peripheral artery, the thickness e 2 of the tube 1c obtained at the outlet of step 4 was between 0.16mm and 0.18mm, and was worth on average 0.17mm. For the two aforementioned types of stents, the roughness index R a of the stent 1ç obtained at the end of the process, under the effect of the double electropolishing of steps 3 and 4 dropped to a value between 0.1 μm and 0.4 μm. , and was worth on average 0.2 μm. The roughness measurement R a of the stent 1c and of the initial starting tube 1a was carried out using a TAYLOR-HOBSON surface condition measuring device (TALYSUL F10 model) and a standard wafer of roughness reference BA5 ETRUG 301, the probe of the measuring device had a radius of O, OO25mm; the measuring force was 1 OOmN, the probing length was between 1 mm and 6mm. The measurements were taken on the generatrices of the tube in the longitudinal direction at the level of the middle zone of the tubular stent.
Plus particulièrement, la découpe au laser (étape 2) du tube de départ 1a est réalisée en sorte de conférer à la paroi du tube une configuration géométrique conforme à l'une des trois variantes des figures 2 à 4 qui seront décrites ci-après et qui représentent la structure géométrique du stent à l'état de repos, c'est-à-dire du stent non déployé. Dans chacune de ces trois variantes, le stent obtenu pouvait être implanté dans un conduit vasculaire, après avoir été déployé au moyen d'un ballonnet gonflé sous une faible pression, comprise entre 2 bars et 3 bars. Une fois implanté, le stent exerçait sur la paroi du conduit vasculaire une force radiale suffisante pour s'opposer à la rétractation élastique de la paroi, sans qu'il soit nécessaire de prévoir un dispositif supplémentaire de maintien du stent à l'état déployé.More particularly, the laser cutting (step 2) of the starting tube 1a is carried out so as to give the wall of the tube a geometrical configuration in accordance with one of the three variants of FIGS. 2 to 4 which will be described below and which represent the geometric structure of the stent in the resting state, that is to say of the unexpanded stent. In each of these three variants, the stent obtained could be implanted in a vascular conduit, after having been deployed by means of a balloon inflated under low pressure, between 2 bars and 3 bars. Once implanted, the stent exerted on the wall of the vascular duct a sufficient radial force to oppose the elastic retraction of the wall, without the need for a device additional to maintain the stent in the deployed state.
Si l'on se réfère à l'exemple de réalisation de la figure 2, le stent tubulaire 1ç est un stent articulé, constitué d'une succession de segments annulaires 6, de largeur i1 ( reliés deux à deux dans la direction de l'axe longitudinal 8 du stent, par des connexions courtes 7 de longueur \2. Sur la figure 2, ces connexions 7 ont la forme sensiblement d'un S avec un point d'inflexion central 7a. Chaque segment annulaireIf we refer to the embodiment of Figure 2, the tubular stent 1ç is an articulated stent, consisting of a succession of annular segments 6, of width i 1 ( connected two by two in the direction of l longitudinal axis 8 of the stent, by short connections 7 of length \ 2. In FIG. 2, these connections 7 have the shape substantially of an S with a central inflection point 7a. Each annular segment
6 forme un serpentin apte à se déployer, et est constitué de successions de bras 6a reliés deux à deux par une zone d'articulation 6b. Dans le cas particulier de la figure 2, lorsque le stent 1 ç est au repos, les bras 6a du segment 6 sont sensiblement parallèles et orientés transversalement à l'axe longitudinal 8 du stent, selon un angle a valant approximativement6 forms a coil capable of deploying, and is made up of successions of arms 6a connected two by two by an articulation zone 6b. In the particular case of FIG. 2, when the stent 1 ç is at rest, the arms 6a of the segment 6 are substantially parallel and oriented transversely to the longitudinal axis 8 of the stent, at an angle a being approximately equal
30 ° . Chaque zone d'articulation 6b est constituée par un segment orienté sensiblement perpendiculairement à l'axe longitudinal 8 du stent. Les connexions 7 relient deux segments annulaires 6 adjacents par l'intermédiaire de leurs zones d'articulation respectives 6b. Plus particulièrement, sur la figure 2, les segments annulaires 6 sont orientés successivement selon des angles a opposés, et les zones d'articulation30 °. Each articulation zone 6b is constituted by a segment oriented substantially perpendicular to the longitudinal axis 8 of the stent. The connections 7 connect two adjacent annular segments 6 by means of their respective articulation zones 6b. More particularly, in FIG. 2, the annular segments 6 are oriented successively at opposite angles, and the articulation zones
6b de deux segments 6 adjacents sont alignés dans la direction de l'axe longitudinal 8 du stent 1ç_. Deux segments annulaires 6 adjacents et leurs connexions 7 forment une pluralité de cellules C déployables , dont l'une est représentée en traits hachurés sur la figure 2.6b of two adjacent segments 6 are aligned in the direction of the longitudinal axis 8 of the stent 1ç_. Two adjacent annular segments 6 and their connections 7 form a plurality of deployable C cells, one of which is shown in hatched lines in FIG. 2.
Chaque zone d'articulation 6b d'un segment annulaire 6 est reliée à deux bras 6a et à une connexion 7 par l'intermédiaire respectivement de trois pivots P-,, P2, et P3 permettant la déformation du stent 1ç_ lors de l'expansion du ballonnet sur lequel le stent est monté. Sur la figure 2, le pivot P2 correspond à l'articulation d'un bras 6a faisant un angle A, par rapport à la zone d'articulation 6b ; dans l'exemple illustré, l'angle A est supérieur à 90° et vaut plus particulièrement environ 120 ° ; le pivot P^ correspond à l'articulation d'un bras 6a faisant un angle B avec la zone d'articulation 6b ; cet angle B est inférieur à 90 ° et vaut plus particulièrement environ 30 ° ; le pivot P3 correspond à la jonction d'une zone d'articulation 6b avec une connexion 7.Each articulation zone 6b of an annular segment 6 is connected to two arms 6a and to a connection 7 via respectively three pivots P- ,, P 2 , and P 3 allowing the deformation of the stent 1ç_ during l expansion of the balloon on which the stent is mounted. In FIG. 2, the pivot P 2 corresponds to the articulation of an arm 6a making an angle A, with respect to the articulation zone 6b; in the example illustrated, the angle A is greater than 90 ° and is more particularly about 120 °; the pivot P ^ corresponds to the articulation of an arm 6a making an angle B with the articulation zone 6b; this angle B is less than 90 ° and is worth more particularly around 30 ° ; the pivot P 3 corresponds to the junction of an articulation zone 6b with a connection 7.
Lorsque le stent 1ç passe de son état de repos de la figure 2, à son état déployé sous l'effet d'expansion d'un ballonnet, les cellules C s'ouvrent , de telle sorte que chaque bras 6a fait sensiblement un angle de 45 ° par rapport à l'axe longitudinal 8 du stent. Chaque bras 6a d'angle A s'ouvre d'un angle σ, d'environ 15 ° , tandis que chaque bras 6a d'angle B s'ouvre d'un angle a2 d'environ 75 ° .When the stent 1c goes from its resting state of FIG. 2, to its deployed state under the effect of the expansion of a balloon, the cells C open, so that each arm 6a makes a substantially angle of 45 ° relative to the longitudinal axis 8 of the stent. Each arm 6a of angle A opens at an angle σ, of approximately 15 °, while each arm 6a of angle B opens at an angle a 2 of approximately 75 °.
Dans un exemple préféré de réalisation, la largeur ^ de chaque segment 6 est de préférence comprise entre 1 mm et 1 ,5mm. Plus particulièrement, pour un stent destiné à être implanté dans une artère coronaire , cette largeur L, est de préférence comprise entre 1 mm et 1 ,2mm ; pour un stent destiné à être implanté dans une artère périphérique, cette largeur 1, est de préférence de l'ordre de 1 ,4mm. La longueur [2 des connexions 7 vaut sensiblement 0,5mm. L'épaisseur Ep des segments annulaires 6 est égale à L'épaisseur des connexions 7 et vaut sensiblement 0, 1 mm.In a preferred embodiment, the width ^ of each segment 6 is preferably between 1 mm and 1.5 mm. More particularly, for a stent intended to be implanted in a coronary artery, this width L is preferably between 1 mm and 1.2 mm; for a stent intended to be implanted in a peripheral artery, this width 1 is preferably of the order of 1.4 mm. The length [ 2 of the connections 7 is approximately 0.5 mm. The thickness E p of the annular segments 6 is equal to the thickness of the connections 7 and is substantially equal to 0.1 mm.
L'exemple de réalisation de la figure 3 se différencie de celui de la figure 2 par la géométrie des zones d'articulation 6b des segments annulaires 6. Chaque zone d'articulation 6b_ est constituée par deux segments courbes S, et S2 formant entre eux un angle β valant sensiblement 90 ° . Les deux angles A et B des pivots P, et P2 sont avantageusement supérieurs à 90 ° , ce qui facilite l'ouverture du stent, comparativement au stent de la figure 2 pour lequel seul l'un des deux angles, en l'occurrence l'angle A, constitue un angle obtus. Dans l'exemple particulier de la figure 3, les angles a et β valent environ 135 ° .The embodiment of FIG. 3 differs from that of FIG. 2 by the geometry of the articulation zones 6b of the annular segments 6. Each articulation zone 6b_ consists of two curved segments S, and S 2 forming between them an angle β being substantially 90 °. The two angles A and B of the pivots P, and P 2 are advantageously greater than 90 °, which facilitates the opening of the stent, compared to the stent of FIG. 2 for which only one of the two angles, in this case the angle A constitutes an obtuse angle. In the particular example of FIG. 3, the angles a and β are worth approximately 135 °.
L'exemple de la figure 4 se différencie de celui de la figure 3 , d'une part en ce que les bras 6a des segments annulaires 6 sont orientés sensiblement parallèlement à l'axe longitudinal 8 du stent, et d'autre part en ce que les connexions 7 ont une forme différente et sont orientées dans une direction transversale d'angle y par rapport à l'axe longitudinal 8 du stent.The example of FIG. 4 differs from that of FIG. 3, on the one hand in that the arms 6a of the annular segments 6 are oriented substantially parallel to the longitudinal axis 8 of the stent, and on the other hand in that that the connections 7 have a different shape and are oriented in a transverse direction with an angle y relative to the longitudinal axis 8 of the stent.
L'orientation des bras 6a parallèlement à l'axe longitudinal 8, combinée à la structure à deux segments ST et S2 des zones d'articulation 6b, permet avantageusement d'avoir une meilleure symétrie d'ouverture du stent, chaque bras 6a s'ouvrant sensiblement du même angle, c'est-à-dire d'environ 45 ° .The orientation of the arms 6a parallel to the longitudinal axis 8, combined with the structure with two segments S T and S 2 of the articulation zones 6b, advantageously makes it possible to have better symmetry of opening of the stent, each arm 6a opening at substantially the same angle, i.e. about 45 °.
L'orientation des connexions 7 transversalement à l'axe longitudinal 8 du stent permet de réaliser des connexions 7 dont la longueur est plus importante, ce qui permet une meilleure compensation de la diminution de la longueur du stent lors de son ouverture. Plus particulièrement, dans l'exemple de la figure 4, les connexions 7 sont constituées par un segment ondulé avec quatre points d'inflexion 7a pour leur allongement . Cette structure particulière permet d'avoir une réserve de longueur plus importante comparativement aux connexions 7 des figures 2 et 3. The orientation of the connections 7 transversely to the longitudinal axis 8 of the stent makes it possible to produce connections 7 whose length is greater, which allows better compensation for the reduction in the length of the stent when it is opened. More particularly, in the example of FIG. 4, the connections 7 consist of a wavy segment with four inflection points 7a for their elongation. This particular structure makes it possible to have a greater length reserve compared to the connections 7 of FIGS. 2 and 3.

Claims

REVENDICATIONS
1 . Endoprothèse (1ç_), plus communément appelée "stent", qui est destinée à être implantée dans un conduit vasculaire en étant déployée sous l'effet d'expansion d'un ballonnet, qui une fois implantée et déployée ne nécessite pas de moyen supplémentaire pour son maintien à l'état déployé et présente une force radiale suffisante pour s'opposer à la rétractation élastique de la paroi du conduit vasculaire, et qui est obtenue par découpe d'un tube en acier inoxydable, caractérisée en ce qu'elle présente une malléabilité suffisamment importante pour permettre son ouverture par expansion d'un ballonnet sous une pression inférieure ou égale à 3 bars et en particulier sous une pression comprise entre 2 bars et 3 bars.1. Endoprosthesis (1ç_), more commonly called "stent", which is intended to be implanted in a vascular duct by being deployed under the effect of expansion of a balloon, which once implanted and deployed does not require additional means for maintaining it in the deployed state and having a radial force sufficient to oppose the elastic retraction of the wall of the vascular duct, and which is obtained by cutting a stainless steel tube, characterized in that it has a malleability sufficiently high to allow its opening by expansion of a balloon under a pressure less than or equal to 3 bars and in particular under a pressure between 2 bars and 3 bars.
2. Endoprothèse selon la revendication 1 caractérisée en ce qu'elle est obtenue en réalisant les opérations ci-après sur un tube en acier inoxydable (1 a), présentant une dureté et une épaisseur (e^ initiales supérieures à la dureté et à l'épaisseur (e2) recherchées pour l'endoprothèse finale :2. Endoprosthesis according to claim 1 characterized in that it is obtained by carrying out the operations below on a stainless steel tube (1a), having a hardness and a thickness (initial e ^ greater than the hardness and l '' thickness (e 2 ) sought for the final stent:
- découpe de la paroi du tube (1 a) et nettoyage par polissage électrolytique, - traitement thermique d'hypertrempe (4), en sorte de diminuer la dureté de l'acier inoxydable, suivi d'un deuxième traitement de polissage électrolytique (5) permettant de diminuer l'épaisseur initiale (e.,) du tube (1a) de départ tout en améliorant son état de surface.- cutting of the wall of the tube (1 a) and cleaning by electrolytic polishing, - thermal treatment of hyperhardening (4), so as to reduce the hardness of the stainless steel, followed by a second electrolytic polishing treatment (5 ) making it possible to reduce the initial thickness (e.,) of the starting tube (1a) while improving its surface condition.
3. Endoprothèse selon la revendication 1 caractérisée en ce qu'elle présente une dureté Vickers comprise entre 200HV et 240HV.3. Endoprosthesis according to claim 1 characterized in that it has a Vickers hardness between 200HV and 240HV.
4. Endoprothèse selon les revendications 2 et 3 caractérisée ne ce qu'elle est obtenue à partir d'un tube en acier inoxydable de départ (1 a) présentant une dureté Vickers initiale comprise entre 360HV et 300HV.4. Endoprosthesis according to claims 2 and 3 characterized in that it is obtained from a starting stainless steel tube (1a) having an initial Vickers hardness between 360HV and 300HV.
5. Endoprothèse selon l'une des revendication 1 à 3 destinée à être implantée dans une artère coronaire caractérisée en ce qu'elle présente une épaisseur (e2l comprise entre 0,06 et 0,08 mm. 5. Endoprosthesis according to one of claims 1 to 3 intended to be implanted in a coronary artery characterized in that it has a thickness (e 2 l between 0.06 and 0.08 mm.
6. Endoprothèse selon les revendications 2 et 5 caractérisée en ce qu'elle est obtenue à partir d'un tube en acier inoxydable de départ (1 a) présentant une épaisseur initiale de l'ordre de 0, 1 mm.6. Endoprosthesis according to claims 2 and 5 characterized in that it is obtained from a starting stainless steel tube (1a) having an initial thickness of the order of 0.1 mm.
7. Endoprothèse selon l'une des revendications 1 à 3 destinée à être implantée dans une artère périphérique, caractérisée en ce qu'elle présente une épaisseur (e2l comprise entre 0,16mm et 0, 18mm.7. Endoprosthesis according to one of claims 1 to 3 intended to be implanted in a peripheral artery, characterized in that it has a thickness (e 2 l between 0.16mm and 0.18mm.
8. Endoprothèse selon les revendications 2 et 7 caractérisée en ce qu'elle est obtenue à partir d'un tube en acier inoxydable de départ (1 a) présentant une épaisseur initiale de l'ordre de 0,2mm. 8. Endoprosthesis according to claims 2 and 7 characterized in that it is obtained from a starting stainless steel tube (1a) having an initial thickness of the order of 0.2mm.
9. Endoprothèse selon l'une des revendications 1 à 8 caractérisée en ce qu'elle présente un indice de rugosité Ra compris entre 0, 1 m et 0,4 vm, et plus particulièrement de l'ordre de 0,2μm.9. Endoprosthesis according to one of claims 1 to 8 characterized in that it has a roughness index R a between 0.1 m and 0.4 vm, and more particularly of the order of 0.2 μm.
10. Endoprothèse selon les revendications 2 et 9 caractérisée en ce qu'elle est obtenue à partir d'un tube en acier inoxydable de départ (1a) présentant un indice de rugosité Ra d'environ 0,8μm.10. Endoprosthesis according to claims 2 and 9 characterized in that it is obtained from a starting stainless steel tube (1a) having a roughness index R a of about 0.8 μm.
1 1. Endoprothèse selon l'une des revendications 1 à 10 caractérisée en ce qu'elle est constituée par une succession de segments annulaires (6) articulés deux à deux par des connexions (7).1 1. Endoprosthesis according to one of claims 1 to 10 characterized in that it is constituted by a succession of annular segments (6) articulated two by two by connections (7).
12. Endoprothèse selon la revendication 1 1 caractérisée en ce que chaque segment annulaire (6) forme un serpentin constitué par une succession de bras (6a) reliés deux à deux par une zone d'articulation (6b), en ce que chaque zone d'articulation (6b) est constituée par deux segments courts {S^) et (S2) formant entre eux un angle [β), et en ce que chaque segment (S^) et (S2) se prolonge par un bras (6a) selon un angle (A) ou (B) supérieur ou égal à 90 ° .12. Endoprosthesis according to claim 1 1 characterized in that each annular segment (6) forms a serpentine formed by a succession of arms (6a) connected two by two by a zone of articulation (6b), in that each zone d articulation (6b) consists of two short segments (S ^) and (S 2 ) forming between them an angle [β), and in that each segment (S ^) and (S 2 ) is extended by an arm ( 6a) at an angle (A) or (B) greater than or equal to 90 ° .
13. Endoprothèse selon la revendication 1 1 caractérisée en ce que l'angle (β) vaut environ 90 ° et les angles A et B valent sensiblement 135 ° .13. Endoprosthesis according to claim 1 1 characterized in that the angle (β) is approximately 90 ° and the angles A and B are substantially 135 °.
14. Endoprothèse selon l'une des revendications 12 ou 13 caractérisée en ce que les bras (6a) de chaque segment annulaire (6) sont orientés sensiblement parallèlement à l'axe longitudinal (8) de l'endoprothèse. 14. Endoprosthesis according to one of claims 12 or 13 characterized in that the arms (6a) of each annular segment (6) are oriented substantially parallel to the longitudinal axis (8) of the endoprosthesis.
15. Endoprothèse selon l'une des revendications 1 1 à 14 caractérisée en ce que chaque connexion (7) a sensiblement la forme d'un S avec un point d'inflexion central (7a).15. Endoprosthesis according to one of claims 1 1 to 14 characterized in that each connection (7) has substantially the shape of an S with a central inflection point (7a).
16. Endoprothèse selon l'une des revendications 1 1 à 14 caractérisée en ce que chaque connexion (7) est orientée transversalement selon un angle (y) par rapport à l'axe longitudinal (8) de l'endoprothèse, et est constituée par un segment ondulé comportant au moins quatre points d'inflexion (7a).16. Endoprosthesis according to one of claims 1 1 to 14 characterized in that each connection (7) is oriented transversely at an angle (y) relative to the longitudinal axis (8) of the endoprosthesis, and is constituted by a wavy segment comprising at least four points of inflection (7a).
17. Endoprothèse selon l'une des revendications 1 1 à 16 caractérisée en ce que la largeurϋ!) des segments annulaires (6) est comprise entre 1 mm et 1 ,5mm. 17. Endoprosthesis according to one of claims 1 1 to 16 characterized in that the widthϋ ! ) annular segments (6) is between 1 mm and 1.5 mm.
PCT/FR1998/002645 1997-12-09 1998-12-07 Stainless steel prosthesis to be implanted in a vascular duct using an inflatable balloon WO1999029264A1 (en)

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FR9715816A FR2771921B1 (en) 1997-12-09 1997-12-09 STAINLESS STEEL STENT TO BE IMPLANTED IN A VASCULAR CONDUIT USING AN INFLATABLE BALLOON
FR97/15816 1997-12-09

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8940003B2 (en) 2008-02-22 2015-01-27 Covidien Lp Methods and apparatus for flow restoration
US9039749B2 (en) 2010-10-01 2015-05-26 Covidien Lp Methods and apparatuses for flow restoration and implanting members in the human body
US10076399B2 (en) 2013-09-13 2018-09-18 Covidien Lp Endovascular device engagement
US10342683B2 (en) 2002-07-19 2019-07-09 Ussc Medical Gmbh Medical implant having a curlable matrix structure and method of use
US10413310B2 (en) 2007-10-17 2019-09-17 Covidien Lp Restoring blood flow and clot removal during acute ischemic stroke
US10722255B2 (en) 2008-12-23 2020-07-28 Covidien Lp Systems and methods for removing obstructive matter from body lumens and treating vascular defects
US11337714B2 (en) 2007-10-17 2022-05-24 Covidien Lp Restoring blood flow and clot removal during acute ischemic stroke

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0274846A1 (en) * 1986-12-09 1988-07-20 Boston Scientific Corporation Apparatus for treating hypertrophy of the prostate gland
US5190058A (en) * 1991-05-22 1993-03-02 Medtronic, Inc. Method of using a temporary stent catheter
EP0705577A1 (en) * 1994-08-12 1996-04-10 Meadox Medicals, Inc. High strength and high density intraluminar wire stent
WO1997032543A1 (en) * 1996-03-05 1997-09-12 Divysio Solutions Ulc. Expandable stent and method for delivery of same
WO1997040780A1 (en) * 1996-04-26 1997-11-06 Jang G David Intravascular stent
US5722979A (en) * 1997-04-08 1998-03-03 Schneider (Usa) Inc. Pressure assisted ultrasonic balloon catheter and method of using same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0274846A1 (en) * 1986-12-09 1988-07-20 Boston Scientific Corporation Apparatus for treating hypertrophy of the prostate gland
US5190058A (en) * 1991-05-22 1993-03-02 Medtronic, Inc. Method of using a temporary stent catheter
EP0705577A1 (en) * 1994-08-12 1996-04-10 Meadox Medicals, Inc. High strength and high density intraluminar wire stent
WO1997032543A1 (en) * 1996-03-05 1997-09-12 Divysio Solutions Ulc. Expandable stent and method for delivery of same
WO1997040780A1 (en) * 1996-04-26 1997-11-06 Jang G David Intravascular stent
US5722979A (en) * 1997-04-08 1998-03-03 Schneider (Usa) Inc. Pressure assisted ultrasonic balloon catheter and method of using same

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10342683B2 (en) 2002-07-19 2019-07-09 Ussc Medical Gmbh Medical implant having a curlable matrix structure and method of use
US11426293B2 (en) 2002-07-19 2022-08-30 Ussc Medical Gmbh Medical implant
US10413310B2 (en) 2007-10-17 2019-09-17 Covidien Lp Restoring blood flow and clot removal during acute ischemic stroke
US11337714B2 (en) 2007-10-17 2022-05-24 Covidien Lp Restoring blood flow and clot removal during acute ischemic stroke
US8940003B2 (en) 2008-02-22 2015-01-27 Covidien Lp Methods and apparatus for flow restoration
US9161766B2 (en) 2008-02-22 2015-10-20 Covidien Lp Methods and apparatus for flow restoration
US10456151B2 (en) 2008-02-22 2019-10-29 Covidien Lp Methods and apparatus for flow restoration
US11529156B2 (en) 2008-02-22 2022-12-20 Covidien Lp Methods and apparatus for flow restoration
US10722255B2 (en) 2008-12-23 2020-07-28 Covidien Lp Systems and methods for removing obstructive matter from body lumens and treating vascular defects
US9039749B2 (en) 2010-10-01 2015-05-26 Covidien Lp Methods and apparatuses for flow restoration and implanting members in the human body
US10426644B2 (en) 2010-10-01 2019-10-01 Covidien Lp Methods and apparatuses for flow restoration and implanting members in the human body
US10076399B2 (en) 2013-09-13 2018-09-18 Covidien Lp Endovascular device engagement

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EP0961599A1 (en) 1999-12-08
FR2771921A1 (en) 1999-06-11
FR2771921B1 (en) 2000-03-24

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