Abstract:
A device includes an expandable implant and a hollow stent internally defining a central passage. The hollow stent defines a retention opening of the implant near the distal end thereof. The inventive device also includes a wire-type link for releasably fixing the implant to the stent, which has a traction section introduced into the opening and extending inside the central passage. For the wire-type link, the device includes an internal insulation channel arranged in the central passage and axially fixed with respect to the stent. The insulation channel receives only one wire-type link and defines a channel which is devoid of a link at least between the proximal end of the stent and the retention opening and is placed in the central channel.

Description:
This application is a 371 of PCT/FR2006/001321 filed on Jun. 12, 2006, which draws priority from France 0506081 filed on Jun. 15, 2005. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to device for treating a blood vessel comprising at least one implant, deployable between a contracted state and an expanded state. A hollow prop internally delimits a central passage between a proximal end and a distal end, and in the vicinity of its distal end, the hollow prop defines defining at least one opening for retaining the implant. At least one filamentary line releasably fixes the implant to the prop, and each filamentary line comprises a pulling portion engaged in the opening and extending into the central passage at least as far as a control end which can be operated from the proximal end of the prop. 
     A device of this type is used for releasing implants into a blood vessel, such as tubular endoprostheses usually referred to as “stents” or other types of endoprostheses, such as endovalves. 
     A device of the aforementioned type is disclosed in FR-A-2 863 160. In this device, an endoprosthesis is mounted coaxially on a hollow prop. The endoprosthesis is held in its refracted state with the aid of two filamentary lines which surround the endoprosthesis at its ends. The filamentary lines are respectively engaged in the distal and proximal retaining openings provided in the prop. Each filamentary line comprises a control portion which extends into the prop as far as a respective control end accessible to the user through a respective lateral branch of the prop. In this device, each end of the endoprosthesis can be released independently of the other end. Thus, the control portion of one of the filamentary lines is displaced inside the prop towards the distal end so as to disengage the corresponding end of the endoprosthesis. The filamentary line is then extracted from the device when the endoprosthesis has been satisfactorily placed in the vessel. 
     A surgical guide is pre-positioned in the blood vessel in order to insert the device into the patient&#39;s blood vessel. Next, the prop bearing the endoprosthesis is inserted into the vessel by being slid along the guide. During this insertion, or during the subsequent movement of the filamentary lines, the lines and the guide may become entangled, which adversely affects the reliability of the device. 
     SUMMARY OF THE INVENTION 
     An object of the invention is therefore to provide a device for treating a blood vessel which can be precisely positioned in the vessel and which has improved reliability. For each filamentary line, the device comprises an internal insulating duct provided in the central passage and axially fixed with respect to the prop, and each insulating duct receives only one line and delimits, in the central passage, a guiding duct with no line at least between the proximal end of the prop and a retaining opening. 
     The device according to the invention may comprise one or more of the following features taken in isolation or in any technically feasible combination. 
     Each insulating duct can delimit a channel for receiving the line extending in cross-section over part of a circumference surrounding a longitudinal axis of the central passage. 
     Each insulating duct can have a distal passage extending substantially opposite an associated retaining opening, each line being engaged in the distal passage. 
     Each insulating duct can have a distal end sealed in a bevelled manner. 
     Each insulating duct can be engaged in the retaining opening and can comprise a collar disposed on an external surface of the prop, the collar delimiting the distal passage. 
     Each insulating duct can be integral with the prop substantially along the entire length of the insulating duct, or each insulating duct can be integral with the prop. 
     The prop can comprise a proximal passage opening and a distal passage opening which are substantially coaxial. The guiding duct with no line extends between the openings and is delimited, in the vicinity of at least one of the passage openings, by a distally diverging surface. 
     The device can comprise at least two filamentary lines, the insulating ducts associated with at least two lines being arranged on the periphery of the guiding duct with no line. 
     The device can comprise only one prop, at least two longitudinally spaced retaining openings being provided in the prop. 
     The device can comprise an element for joint movement of at least two lines, the movement element being disposed outside the prop, and the control ends of the two lines are fixed to the movement element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood after reading the following description, given purely by way of example and with reference to the attached drawings, in which: 
         FIG. 1  is an elevated view of a first treatment device according to the invention; 
         FIG. 2  is an enlarged partial sectional view following a medial longitudinal plane of the device in  FIG. 1 ; 
         FIG. 3  is an enlarged partial cross-section following a transverse plane III-III of a detail in  FIG. 1 ; 
         FIG. 4  is a detailed view of  FIG. 2 ; 
         FIG. 5  is a view similar to  FIG. 1 , the endoprosthesis being deployed in a reversible manner; 
         FIG. 6  is a partial cross-section following a medial longitudinal plane of a second device according to the invention; 
         FIG. 7  is a view similar to  FIG. 3  of a third device according to the invention; and 
         FIG. 8  is a view similar to  FIG. 4  of the third device according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The device illustrated in  FIGS. 1 to 5  includes a tubular endoprosthesis  11  mounted in a coaxial manner on a single prop  13  and connected to the prop  13  by releasable retaining means. 
     The endoprosthesis  11  comprises a tubular stainless steel mesh which has resilient properties. The endoprosthesis is thus self-expandable. 
     As is known per se, the endoprosthesis  11  can spontaneously deform from a compressed state, in which it has a small diameter ( FIG. 1 ), to an expanded state, in which it has a greater diameter ( FIG. 5 ), the expanded state being its rest state. 
     At a distal end  15  of the endoprosthesis, the mesh has wires doubled over to form loops  17 . 
     In the embodiment illustrated in  FIGS. 1 and 2 , the prop  13  comprises a hollow, resilient, wire tubular wall  13 A which delimits a central passage  14 . 
     The prop  13  extends longitudinally along a longitudinal axis X-X′ between a distal end  19  for implantation in the blood vessel and a proximal end  21  which provides access for a surgeon. 
     At the distal and proximal ends  19 ,  21  of the prop  13  there are respective passage openings  22 A,  22 B of axis X-X′ which open into the central passage  14 . The distal and proximal retaining openings  23 A and  23 B, which are longitudinally offset, are arranged laterally in the prop  13 . In this embodiment, the openings  23 A and  23 B are arranged on opposite sides with respect to a medial longitudinal plane of the prop  13 . The distance separating the distal retaining opening  23 A from the proximal retaining opening  23 B is substantially equal to the length of the endoprosthesis  11  in its retracted state, taken in a longitudinal direction. 
     In addition, the prop  13  comprises distal and proximal hollow branches  25 A,  25 B in the vicinity of its proximal end  21 . The branches  25 A and  25 B are longitudinally offset along the prop  13  and connect to the passage  14  inside the prop  13 . A control passage  27 A,  27 B is provided at a free end of each branch  25 A,  25 B. 
     As illustrated in  FIG. 2 , the prop  13  comprises, for each retaining opening  23 A,  23 B, an internal insulating duct  29 A,  29 B for insulating the retaining means releasably connected to a respective branch  25 A,  25 B. The insulating ducts  29 A,  29 B are made from a resilient self-supporting plastics material. They are formed by tubes with a cylindrical cross-section. Each insulating duct  29 A,  29 B extends longitudinally in the central passage  14  between a proximal end  31 A,  31 B engaged in the control passage  27 A,  27 B and a distal end  33 A,  33 B arranged at the distal end  19  of the prop in the passage  14 . The proximal end  31 A,  31 B of each insulating duct  29 A,  29 B is fitted with a stopper  35 A,  35 B for sealing the control passage  27  screwed onto the corresponding branch  25 A,  25 B. Each insulating duct  29 A,  29 B is sealed at its distal end  33 A,  33 B, thus forming a bevel which extends towards the distal end of the prop  13 . The ducts  29 A,  29 B internally delimit channels  37 A,  37 B for receiving the releasable retaining means. 
     Each insulating duct  29 A,  29 B defines a distal passage  39 A,  39 B which extends longitudinally substantially opposite an associated retaining opening  23 A,  23 B and which opens out into the channel  37 A,  37 B. Each insulating duct  29 A,  29 B is thus fixed to the prop  13  by its proximal end  31 A,  31 B, but remains free at its distal end  33 A,  33 B. In a variant, each duct  29 A,  29 B is also fixed to the prop  13  at its distal end  33 A,  33 B by an adhesive point. 
     As illustrated in  FIG. 3 , each channel  37 A,  37 B has a cylindrical transverse cross-section which extends over part of a circumference surrounding axis X-X′ of the central passage  16 . In the example shown, the ducts  29 A,  29 B are arranged on the same circumference surrounding the longitudinal axis X-X′. Furthermore, each channel  37 A,  37 B extends radially in transverse cross-section over part of the distance which separates axis X-X′ and the tubular wall  13 A. 
     As illustrated in  FIG. 3 , the space in the passage  14  between the insulating ducts  29 A,  29 B and the wall  13 A forms a guiding duct  41  for moving and guiding a surgical guide  43 . The insulating ducts  29 A and  29 B are disposed at the periphery of the guiding duct  41 . 
     The releasable device for retaining the endoprosthesis  11  comprises a retaining rod  51 , distal and proximal retaining wires  53 A and  53 B, and a bar  54  for controlling the retaining wires. 
     The retaining rod  51  is disposed in the central passage  14 . The length of the rod  51  is greater than or equal to the distance between the distal retaining opening  23 A and the proximal end  21  of the prop  13 . As illustrated in  FIG. 2 , the rod  51  comprises an active part  55  arranged in the vicinity of the distal end  19  and an operating part  57  which extends as far as the proximal end  21  of the prop  13 . 
     The rod  51  can move in translation inside the prop  13  between a retaining position in which the active part  55  of the rod is opposite the two retaining openings  23 A and  23 B, an intermediate position in which the active part  55  is opposite the proximal retaining opening  23 B and away from the distal retaining opening  23 A, and a release position in which the active part  55  is away from the two retaining openings  23 A and  23 B. 
     The rod  51  is fixed to the proximal end  21  of the prop  13  by a removable stopper  59  which seals the proximal passage opening  22 B. 
     As illustrated in  FIG. 4 , the stopper  59  has a central sleeve  61  of axis X-X′. The proximal base  63  of the rod  51  is embedded in a wall of the sleeve  61  in such a way that the rod  51  is axially offset with respect to axis X-X′. The sleeve  61  delimits a central channel  65  of axis X-X′ which provides a distal entrance  67  into the central passage  14  and a proximal entrance  69  outside the prop  13 . The distal entrance  67  is delimited by a distally diverging (outwardly flared) surface of the sleeve  61 , and the proximal entrance  69  is delimited by a surface of the prop  13  diverging towards the exterior. 
     In the example illustrated in  FIGS. 1 to 5 , each retaining wire  53 A,  53 B comprises only one strand which includes an end eyelet  71 A,  71 B, a tightening loop  73 A,  73 B and a control portion  75 A,  75 B. 
     In a variant (not illustrated), each retaining wire  53 A,  53 B comprises two parallel strands connected to one another at least by an end part. The eyelet is formed directly by means of the end part, engaged around the rod  51 . 
     The end eyelet  71 A,  71 B is formed at a distal end of the strand. It is formed of a closed loop with a small diameter. The active part  55  of the rod  51  is engaged in the eyelet  71 A,  71 B when the rod  51  is in its retaining position. The eyelet  71 A,  71 B can also be deformed in such a way that its size, when it is deformed, is substantially equal to double the size of the strand. This size is smaller than the internal diameter of the loops  17 . The eyelet  71 A,  71 B is connected to the tightening loop  73 A,  73 B by a section  76 A engaged in the corresponding retaining opening  23 A,  23 B. 
     In the example illustrated in  FIG. 1 , the tightening loop  73 A,  73 B is formed by a strand portion, slidingly engaged in the end loops  17  of the mesh of the endoprosthesis  11 , following a circumference of the endoprosthesis  11 , surrounding a longitudinal axis. Each tightening loop  73 A,  73 B fixes the endoprosthesis  11  to the prop  13 . Furthermore, the active length of the tightening loop  73 A,  73 B can be varied in such a way that it controls deployment of the endoprosthesis  11  with respect to the prop  13  as described hereinafter. 
     As illustrated in  FIG. 2 , each control portion  75 A,  75 B extends into an insulating duct  29 A,  29 B between its distal passage  39 A,  39 B and the control passage  27 A,  27 B of the corresponding control branch  25 A,  25 B. Each insulating duct  29 A,  29 B thus receives only one control portion  75 A,  75 B which is insulated by the duct  41 . As a result, the duct  41  for moving the guide  43  in the central passage  14  has no retaining wire  53 A,  53 B between the proximal end  21  of the prop and the proximal retaining opening  23 A, thus allowing the guide  43  to be moved without mechanically interacting with the wires  53 A,  53 B. 
     A control end  77 A,  77 B of the control portion  75 A,  75 B is engaged across the control passage  27 A,  27 B. Thus, a part  79 A,  79 B of the portion projects outside the branch  25 A,  25 B through the stopper  35 A,  35 B. The length of the projecting part  79 A,  79 B is variable and controls the length of the tightening loop  73 A,  73 B. 
     Hence, an increase in the length of the projecting part  79 A,  79 B causes displacement of the control portion  75 A,  75 B with respect to the prop  13  towards the proximal end  21  of the prop, as well as a corresponding decrease in the active length of the tightening loop  73 A,  73 B. As a result, the endoprosthesis  11  is clamped against the prop  13  at the tightening loop  73 A,  73 B. When the endoprosthesis  11  is in its retracted state against the prop  13 , the control portion  75 A,  75 B is in a drawn position. 
     Conversely, a decrease in the length of the projecting part  79 A,  79 B causes displacement of the control portion  75 A,  75 B with respect to the prop  13  towards the distal end  19  of the prop  13 , as well as an increase in the active length of the tightening loop  73 A,  73 B and, as a result, deployment of the endoprosthesis  11  at a distance from the prop  13 , at the tightening loop  73 A,  73 B. When the endoprosthesis  11  is in its expanded state, the control portion  75 A,  75 B is in a relaxed position. 
     Each stopper  35 A,  35 B comprises a diametrically adjustable central opening in which the projecting part  79 A,  79 B is engaged. By setting the diameter of the central opening of the stopper  35 A,  35 B, the projecting part  79 A,  79 B of the control portion  75 A,  75 B is selectively immobilized with respect to the prop  13  and the length of the projecting part  79 A,  79 B is fixed. As a result, the active length of the tightening loop  73 A,  73 B is also fixed. 
     The control bar  54  comprises a grip  81  and fasteners  83 A,  83 B for releasably fixing the ends of the control portions  75 A,  75 B arranged on both sides of the grip. The grip  81  is arranged outside the passage  14  at a distance from the prop  13 . The free ends of the control portions  75 A,  75 B at the projecting parts  79 A,  79 B are fixed respectively on both sides of the grip  81  of the bar  54 . The bar  54  allows single-handed simultaneous operation of the two control wires  53 A,  53 B, as will be shown hereinafter. 
     By way of example, the operation of the first treatment device according to the invention will now be described. 
     In a first phase, the device is packaged (not shown) with the endoprosthesis  11  in a deployed state similar to that shown in  FIG. 5 . In this configuration, the control rod  51  is in its retaining position. The distal and proximal retaining wires  53 A and  53 B are engaged in the rod  51  and in the mesh of the endoprosthesis  11 . This encapsulation retains the mechanical properties of the endoprosthesis  11 , in particular when the tubular mesh of the endoprosthesis is embedded in an expandable film, such as an elastomer, which is impervious to liquids. 
     In a second phase, the surgeon takes the device out of its packaging. He implants the surgical guide  43  extending in the blood vessel or the vein from the outer insertion point as far as the region of the vein or the artery in which the tubular endoprosthesis is to be implanted. 
     In a third phase, in view of the implantation of the endoprosthesis  11  in the blood vessel or vein, the surgeon simultaneously operates the retaining wires  53 A and  53 B by pulling the grip  81  away from the prop  13  so as to increase the length of the projecting part  79 A,  79 B of the control portion  75 A,  75 B. Thus, he simultaneously displaces the control portions  75 A,  75 B towards the proximal end  21  of the prop  13 . The active length of each tightening loop  73 A,  73 B decreases in such a way that the endoprosthesis  11  is retracted against the prop  13  and securely fixed with respect thereto. 
     In certain cases and in order to maintain minimal radial dimensions, a sheath (not shown) is disposed around the endoprosthesis  11  before the insertion and is withdrawn once insertion has taken place. 
     The endoprosthesis  11  is then in the retracted state illustrated in  FIG. 1  in which the mesh substantially rests against the prop  13 . The endoprosthesis is thus inserted as far as its place of implantation by displacement along the surgical guide  43 . To achieve this, the guide  43  is inserted into the central passage  14  by opening the distal passage  22 A. The insertion of the guide  43  inside the passage  14  is facilitated by the bevelled shape of the distal ends of the ducts  29 A,  29 B. Furthermore, since the control portions  75 A,  75 B of the wires  53 A,  53 B are disposed in the ducts  29 A,  29 B, the guide  43  is free to move in the duct  41  without coming into contact with wires  53 A,  53 B (i.e., the guide  43  can contact the outer surface  93  of each insulating duct  29 A,  29 B, but the guide  43  cannot penetrate through the ducts  29 A,  29 B to contact wires  53 A,  53 B within the ducts  29 A,  29 B). 
     When the end of the guide  43  reaches the proximal end  21  of the prop, the guide  43  penetrates the central channel  65  of the stopper  59 . The diverging shape of the sleeve  61  at the entrance  67  also allows easy guiding of the guide  43 . The prop bearing the endoprosthesis is then displaced along the guide  43 . 
     Once the endoprosthesis  11  has been inserted, the surgeon proceeds with deployment thereof. Depending on the size of the vessel to be treated, the surgeon may choose to deploy either end of the endoprosthesis  11  first. By way of example, deployment of the distal end  15  will now be described. 
     First of all, the surgeon progressively decreases the length of the projecting part  79 A of the control portion  75 A by releasing the part from the stopper  35 A. He displaces the control portion  75 A towards the distal end  19  of the prop  13  with the aid of the bar  54 . As a result, the active length of the tightening loop  73 A increases. 
     The mesh of the endoprosthesis  11  thus deforms spontaneously from the compressed state shown in  FIG. 1  to the deployed state shown in  FIG. 5 . During this deformation, the end loops  17  of the mesh move away from the prop  13  and move closer to the walls P of the vessel to be treated in order to come into contact with the walls P. In a similar manner, the surgeon then effects deployment of the proximal end  85  of the endoprosthesis by the proximal retaining wire  53 B ( FIG. 5 ). 
     Being insulated from one another in each insulating duct  29 A,  29 B, the control portions  75 A,  75 B are reliably displaced and the risk of the wires  53 A,  53 B being blocked is largely reduced. 
     When the surgeon is satisfied with the positioning of the distal end  15  of the endoprosthesis  11 , he moves the retaining rod  51  from its retaining position to the intermediate position. 
     During this movement, the eyelet  71 A of the distal retaining wire  53 A is released from the rod  51 . The surgeon then pulls the control end  77 A with the aid of the bar  54  in order to lead the distal end of the distal retaining wire  23 A to the control passage  27 , then through the loops  17  of the mesh of the endoprosthesis  11 , the inside of the prop  13 , and the control branch  25 A. 
     In a variant, the control portions  75 A,  75 B of the retaining wires  53 A,  53 B are simultaneously released from their stoppers  35 A,  35 B. The surgeon then simultaneously manoeuvres the two control portions  75 A,  75 B with the aid of the grip  81  of the bar. As a result, he can simultaneously deploy the two ends  15 ,  85  of the endoprosthesis  11  by displacing the two ends  83 A,  83 B of the grip  81  towards the stoppers  35 A,  35 B. He may also deploy one of the ends  15 ,  85  of the endoprosthesis by keeping the other end of the endoprosthesis retracted against the prop  13  by displacing only one of the ends  83 A,  83 B of the grip  81  towards the associated stopper  35 A,  35 B. 
     The bar  54  thus facilitates the handling of the device and allows the surgeon to single-handedly select either deployment or retraction of one and/or the other of the ends of the endoprosthesis  11 . 
     In the second device according to the invention, shown in part in  FIG. 6 , the distal passage  39 B is arranged at the distal end  33 B of the insulating duct  29 B. Around the passage  39 B at its distal end  33 B, the insulating duct  29 B also has a collar  87  for application on the wall  13 A of the prop. The duct  29 B is bent in the vicinity of its distal end  33 B which is engaged through the retaining opening  23 B. The collar  85  rests upon an external surface  89  of the prop  13  surrounding the opening  23 B and fixes the duct  29 B to the prop  13 . 
     In the third device according to the invention, shown in  FIG. 7 , the prop  13  comprises a central duct  91  for moving the guide formed by a tubular part of axis X-X′ disposed in the central passage  14  and extending as far as the proximal end  21  of the prop. The central duct  91  is connected to the wall  13 A of the prop  13  by plane axial walls  95 . The axial walls  95  have a transverse cross-section extending radially away from axis X-X′. They delimit, between the central duct  91  and the wall  13 A, a plurality of insulating ducts  29 A,  29 B which receive the retaining wires  53 A,  53 B. The duct  91 , the wall  13 A, and the walls  95  are integral, the prop  13  being able to be produced, for example, by extrusion. 
     Each channel  37 A,  37 B thus has a transverse cross-section in the shape of a truncated angular section which covers part of the annular surface extending between the duct  91  and the wall  13 A of the prop around axis X-X′. The angle formed by two adjacent axial walls  95  is, for example, between 10 and 150°. 
     As shown in  FIG. 8 , the stopper  59  is formed in such a way that the internal surface of the sleeve  61  is internally flush with the internal surface of the duct  91  in order to facilitate the passage of the guide between the duct  91  and the stopper  59 . 
     Owing to the invention which has just been described, it is possible to provide a device for treating a blood vessel which is easily inserted on a surgical guide  43 . The device is therefore placed precisely in a blood vessel. Since the releasable retaining wires  53 A,  53 B of the endoprosthesis  11  are disposed in the insulating ducts  29 A,  29 B, the risk of mechanical interaction between said wires  53 A,  53 B and the guide  43  is largely reduced. Furthermore, the movement of the control portions  75 A,  75 B of the wires is rendered extremely reliable thanks to their arrangement in the internal insulating ducts  29 A,  29 B. 
     The use of a bar  54  connecting the free ends of the control portions  75 A,  75 B of the retaining wires  53 A,  53 B of the endoprosthesis considerably simplifies operation of the device and facilitates use thereof using just one hand. It will be noted that the bar  54  applies to other types of devices for deploying medical implants comprising at least two control wires, in particular those with no insulating ducts  29  as disclosed in application FR 2 863 160. 
     The presence of diverging surfaces at the ends  19 ,  21  of the prop  13  facilitates insertion of the guide  43  into the central passage  14 , either from the distal end towards the proximal end of the prop  13  or the other way round.