FR2860705A1 - Delivery apparatus for prosthesis such as stent has two-position hook on end of pusher wire to release stent after positioning with catheter - Google Patents

Abstract

The apparatus comprises a catheter through which a stent can be delivered with the aid of a sliding pusher wire, a hook made from a nitinol strip with a shape memory effect, fastened to one end of the pusher wire and able occupy two positions. It can be set in a closed position after engagement with a loop on the end of the stent inside the catheter, and an open position to release the loop once the hook emerges from the distal end of the catheter. The apparatus, comprising a catheter (2) through which a stent (1) can be delivered with the aid of a sliding pusher wire (5), has a hook (10) made from a nitinol strip with a shape memory effect, fastened to one end of the pusher wire and able occupy two positions. It can be set in a closed position (PII) after engagement with a loop (7) on the end of the stent inside the catheter, and an open position (PI) to release the loop once the hook emerges from the distal end (4) of the catheter.

Description

1 2860705

  DEVICE FOR DELIVERING ENDOPROTHESIS

  The present invention relates to devices which make it possible to deliver a prosthesis known in the medical field under the term "endoprosthesis" or more generally under that of "stent", for the purpose for example of closing off an aneurysm or analog in a blood vessel such as an artery, and more particularly those which find application in the field of treatment of cerebral aneurysms.

  It is already known devices that deliver stents for the purpose of sealing aneurysms or the like in a blood vessel such as an artery.

  Such devices are for example described in US-A-5 449 373, US-5 195 984, EP-A-0 795 304, EP-A-0 832 618 and WO 96/18359. They are generally constituted by a catheter capable of sliding in translation in a blood vessel or the like. This catheter is further arranged to receive a folded stent adapted to be deployed radially between a first section value and a second section value which are respectively less than and substantially equal to the inner section of the blood vessel, the stent being positioned on or within the catheter in the configuration in which its section has the first value. These devices further comprise means for controlling the release of the stent from the catheter and its radial deployment to bring its section from its first to its second value.

  Such a device is for example also described in FR-A-2 788 216.

  There are other devices for delivering stents, for example those comprising a catheter into which a stent is inserted into its folded position, and a tube slidably mounted in this catheter, which is pushed by its end emerging from the end. proximal of the catheter to eject the stent at the location chosen by the practitioner. Such a device may further comprise a wire also slidably mounted in the tube and emerging at the proximal end of the catheter, this wire allowing in particular to guide the establishment of the stent, to check its position by radiography, etc. .

  This type of device gives good results but it can not meet the particular wishes of practitioners who must implant stents.

  Indeed, they do not allow to pull the stents backwards after they have been brought to a specific location in the catheter, since they only allow to push them into the catheter duct. However, the absence of this function when using a catheter can sometimes create problems for practitioners, particularly for positioning a stent perfectly.

  It is true that there are devices that allow to retreat the stent in the catheter but their structure is relatively complex. As a result, their use by practitioners is relatively difficult and they often give up using them, of course often at the expense of patient comfort.

  The present invention therefore aims to provide a device for delivering a prosthesis known in the medical field under the term "stent", which overcomes at least in part the disadvantages mentioned above.

  More specifically, the subject of the present invention is a device for delivering a prosthesis known in the medical field under the term "stent", comprising: a catheter of internal diameter D, capable of being introduced into a conduit of a human body said catheter thereby having a proximal end and a distal end; a pusher wire slidably mounted in said catheter; and means for connecting the first end of the pusher wire which is adapted to open through the distal end of the catheter. with said stent, characterized in that, when said stent comprises at least one loop, said means for connecting the end of the pusher wire which is adapted to open by the distal end of the catheter, with said stent, are constituted by: at least one hook, said hook being able to take two positions, a closed position in which it cooperates with said loop of the stent when the hook is in ns said catheter and an open position releasing said loop when the hook is outside said catheter, and * means for connecting at least one point of said hook to the first end of the push wire.

  Other features and advantages of the invention will emerge in the course of the following description given with reference to the accompanying drawings for illustrative but not limiting purposes, in which: FIGS. 1 and 2 show, in schematic form, a preferred embodiment of the invention. device according to the invention for delivering a prosthesis known in the medical field under the term "stent", Figure 1 showing the device in a first position, and Figure 2 showing the same device in a second position for releasing the stent as will be explained below.

  It is clearly stated that, in the figures, the same references designate the same elements, whatever the figure on which they appear and whatever the form of representation of these elements. Similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to the other figure.

  The figures represent a preferred embodiment of the object according to the invention, but it is understood that there may be other embodiments that meet the definition of this invention.

  It is also stated that, when, according to the definition of the invention, the object of the invention comprises "at least one" element having a given function, the embodiment described may comprise several of these elements.

  Similarly, if the embodiment of the object according to the invention as illustrated comprises several elements of identical function and if, in the description, it is not specified that the object according to this invention must obligatorily include a particular number of these elements, the object of the invention may be defined as comprising "at least one" of these elements.

  It is furthermore finally specified that when, in the present description, an expression alone defines, without specific specific reference to it, a set of structural characteristics, [for example A = E (a, P, y, ... A, these characteristics can be taken, for the definition of the object of the requested protection, when technically possible, either separately, [for example a, and / or f3, and / or 'y, ...], either in total and / or partial combination, [eg E (a, f3, y), and / or E (a, f3), and / or E ([3, 'y), and / or E (a, y)].

  The present invention relates to a device for delivering a prosthesis known in the medical field under the term "stent" 1.

  It is previously mentioned that a stent is well known in itself and therefore will not be the subject of a particular description, especially since it does not fall within the scope of the protection of the present invention. .

  It is further emphasized that the two figures are only schematic representations, essentially to bring out the structural elements of the preferred embodiment of the device according to the invention. This is how some of the dimensions were deliberately dilated compared to others. These relative scale differences must therefore in no way result in a particular interpretation of the definition of the invention and / or a limitation of its protection as defined in at least one of the appended claims.

  The device comprises, with reference to FIGS. 1 and 2, a catheter 2 of internal diameter D, able to be introduced, in a manner known per se, into a conduit of a human body as mentioned in the preamble of the present description. catheter thereby having a proximal end 3 and a distal end 4.

  The device further comprises a push wire 5 slidably mounted in the catheter 2 and means for connecting with the stent the first end 6 of the push wire 10 5 which is able to open by the distal end 4 of the catheter 2.

  According to one characteristic of the invention, the device is characterized in that, when the stent 1 comprises at least one loop 7, the means for connecting with the stent the first end 6 of the push wire 5 which is able to open by the distal end 4 of the catheter 2, are constituted by at least one hook 10.

  This hook is adapted to take two positions, a closed position PII as illustrated in solid lines in FIG. 1 and in dashed lines in FIG. 2, in which it cooperates with the loop 7 of the stent 1, while retaining it, when the hook is located in the catheter 2, and an open position PI as illustrated in solid lines in Figure 2, in which it releases the loop 7 when it is outside 11 of the catheter.

  The device also comprises means 20 for connecting at least one point of the hook 10 to the first end 6 of the push wire 5.

  It is specified that, for such a device to be functionally operational, it is necessary for the stent to comprise at least one loop 7, such as that shown diagrammatically in solid lines in FIG. 1 and in broken lines in FIG. .

  By "loop" is meant any element that has the shape and / or function of a loop, whether it is specially made or not on the stent. For example, as many stents are made of woven fabrics, knitted or the like, of all shapes, the loop 7 may be constituted by one or more meshes of the fabric, or even by a breakthrough made in the fabric, etc.

  According to a particularly advantageous preferred embodiment, the hook 10 consists of a blade 30 adapted to take at least two states, a first "open" origin state represented in LI in which the blade 30 is substantially rectilinear, and a second so-called "closed" state represented in L2 in which this blade 30 is substantially U-shaped, the blade 30 taking its second U-shaped state when it is stressed and automatically resuming its first "open" state LI when this stress is canceled, as described below when describing the use and operation of the device.

  Advantageously, it is preferable that the maximum overall width of the U, taken perpendicular to the two branches of the U, is equal to, or even less than, the diameter D, so that the blade, in its closed state, takes one configurations respectively illustrated in phantom or solid line in Figure 1.

  For this purpose, according to a preferred embodiment, the blade 30 is shape memory of the elastic type, that is to say that it is made of a material having a certain elasticity. This blade 30 is thus preformed so that, in its original state LI when not subjected to an external stress, it is of generally substantially rectilinear (or slightly curved, which is functionally equivalent), and that, when a stress is applied to it, for example two forces tending to bring its two ends 33, 34 closer together, it takes its U-shaped state L2, but it automatically resumes, elastically, its substantially rectilinear origin state LI, when these two forces are canceled.

  Advantageously, to promote the elastic deformation of the blade to change it from its state LI to its state L2, the blade 30 may have a median portion 31 of a longer or smaller length as required, of smaller thickness that of the two sides bordering on both sides this middle part.

  In addition, so that the hook 10 formed by this blade 30 can perform the function as will be explained below, the blade 30 is preferably arranged so that, when in its second state L2 in the form of U, the ends 33, 34 of the two branches of the U are facing the side wall 32 of the first end 6 of the push wire 5, in contact or not with this wall. However, as will be described below, one of these two ends, in this case the end 33, while facing this side wall 32 will be more integral therewith.

  It is possible that this blade 30 is advantageously made for example of a material known under the trademark Nitinol.

  As mentioned before, the device comprises means 20 for connecting at least one point of the hook 10 to the first end 6 of the push wire 5. In the case where the hook consists of a blade 30 as described above, these means are advantageously constituted by means 40 for securing a first end of the blade 30, in this case the end 33 with reference to the two figures, 2860705 with the first end of the push wire. Preferably, these means 40 are constituted by a crimping ring 35 trapping all at once the first end 33 of the blade 30 and the first end 6 of the push wire.

  According to an advantageous embodiment which has given the Applicant all satisfaction, the push wire is made in the form of a Nitinol filament covered with a twisted stainless steel wire as illustrated, and the ring 35 is made of opaque radio material as platinum or gold.

  The device according to the invention, for delivering a prosthesis known in the medical field under the term "stent", operates and is used as follows: When a practitioner wants to place a stent 1, for example in a cerebral artery a patient, it first introduces the catheter 2 into the artery, as mentioned in the preamble of the present description, by its distal end 4, until this distal end 4 is substantially opposite the where the stent is to be implanted, for example an aneurysm or the like, the proximal end 3 of the catheter still remaining outside the patient's body.

  The practitioner then introduces the stent into the catheter 2 through its proximal end 3 and hooks the hook 10 located at the first end 6 of the push wire 5 to the loop 7 of the stent, that is to say it passes all the firstly the blade 30 when it is in its state LI, in the loop 7, then makes it undergo a deformation, for example manually, to give it its U shape. It is obvious that the assembly consisting of a catheter 2 in which has already been introduced a crew comprising the push wire 5 and the stent 1 mounted in cooperation with the push wire via the hook 10, can be provided in this state to the practitioner, which will avoid a number of manipulations.

  It pushes the crew thus formed in the catheter by acting on the second end 16 of the push wire 5, the latter pushing the stent by its first end 6.

  The U-shape of the blade 30 of course has a transverse dimension as mentioned before, so that the blade 30 remains in this U-shape when it is in the catheter, its end 34 possibly bearing on the inner wall 50 of the catheter (as shown in broken lines in Figure 1) under the action of the elastic force which tends to straighten it.

  The practitioner continues to act on the push wire 5, still pushing it in translation until the stent 1 reaches the distal end 4 of the catheter 2 which is opposite the place where it must be placed in the patient. 'artery.

  However, it is possible that, for various reasons, after partially withdrawing the catheter stent by the distal end 4 of the catheter, the practitioner decides to return it to the catheter, either in part or in full, for example to better reposition the distal end 4 of the catheter 2 so that the stent is in an even better position facing the aneurysm to be treated (or any other location).

  This operation is of course possible as long as the hook 10 has not left the catheter by its distal end 4. Under these conditions, with the structure of the device according to the invention, it suffices to act on the push wire 5 by its second end 16 to pull back in the catheter 2. The hook 10 is still connected to the loop 7, the stent 1 is also pulled back until it is completely in the catheter.

  The practitioner can therefore act again on the catheter itself to refine its position relative to the location of the artery to be treated, and then deliver the stent for implantation in this location.

  To deliver the stent, it acts on the pusher wire by its second end 16 located outside the body of the patient and the catheter 2, until its first end 6 emerges from the distal end 4 of the catheter. In this position, the blade is no longer retained by the inner wall of the catheter and can straighten elastically as shown in Figure 2 and pass, as explained above, its closed state L2 to its open state Li. Then, by making a withdrawal movement on the push wire 5, the blade 30 disengages from the loop 7, leaving the stent at the location of its implantation. The establishment of the stent is complete, the practitioner can remove, both, the catheter 2 and the pusher wire 5 with the blade 30 in its open state LI.

  The embodiment of the device according to the invention described above is the one which is the preferred one of the Applicant, both in terms of the cost of implementation and that of ease of use.

  It is however obvious that there may be other embodiments of the hook 10. For example, it is possible to make a hook 10 consisting of two strips, one end of each strip being secured to the first end 6 of the wire pusher 5, the two other free ends respectively of these two strips abut, under external elastic stress, one on the other or one against the other, forming a closed hook when these slats are held under duress in the catheter and an open hook when they are outside the catheter.

Claims (2)

8 2860705 Claims   1. Device for delivering a prosthesis known in the medical field under the term "stent" (1), comprising: a catheter (2) of internal diameter D, capable of being introduced into a conduit of a human body, said catheter having thereby a proximal end (3) and a distal end (4), - a push wire (5) slidably mounted in said catheter (2), and - means for connecting the first end (6) of the wire pusher (5) which is able to open by the distal end (4) of the catheter (1), with said stent, characterized in that, when said stent (1) comprises at least one loop (7), said means to connect the end (6) of the push wire (5) which is able to open by the distal end (4) of the catheter (2), with said stent, are constituted by: * at least one hook (10), said hook being adapted to take two positions, a closed position (PR) in which it cooperates with said loop (7) of the stent (1) q when the hook is in said catheter (2), and an open position (PI) releasing said loop (7) when the hook is out (11) of said catheter (2), and * means (20) for connecting at least one point of said hook (10) at the first end (6) of the push wire (5).   2. Device according to claim 1, characterized in that said hook (10) consists of a blade (30) adapted to take two states, a first state called "open" (LI) in which said blade (30) is substantially rectilinear and a second so-called "closed" state (L2) in which said blade (30) is substantially U-shaped, said blade (30) taking its U-shape when it is stressed and automatically resumes its shape substantially rectilinear when said constraint is canceled.   3. Device according to claim 2, characterized in that said blade (30) 30 is elastic shape memory.   4. Device according to claim 3, characterized in that said blade (30) has a medial portion (31) of smaller thickness than that of the two parts bordering on either side said middle portion (31).   5. Device according to claim 4, characterized in that said blade (30) is arranged so that, when in its second U-shaped state, the two ends of the two branches of the U are facing each other. the side wall (32) of the first end (6) of the push wire (5).   6. Device according to one of claims 2 to 5, characterized in that said blade (30) is Nitinol (registered trademark).   7. Device according to one of claims 2 to 6, characterized in that the means (20) for connecting at least one point of the hook (10) to the first end (6) of the push wire (5) are constituted by means (40) for securing a first (33) of the two ends (33, 34) of said blade (30) to the first end of the push wire.   8. Device according to claim 7, characterized in that the means (40) for securing the first end (33) of said blade (30) with the first end (6) of the push wire (5) are constituted by a ring crimping device (35) trapping both the first end of said blade and the first end of the push wire.   9. Device according to claim 8, characterized in that said ring (35) is radiopaque material.   10. Device according to one of claims 2 to 9, characterized in that the maximum overall width of the U-shaped blade (30), taken perpendicular to the two branches of the U, is equal to the diameter D.