Abstract:
A kit includes an implantable treatment element ( 13 ) which can be radially deformed between a retracted state and a deployed state, and a sheath ( 15 ) for maintaining the treatment element ( 13 ) in its retracted state. The kit also includes a member ( 19 ) for pulling the treatment element ( 13 ) into the sheath ( 15 ), which includes a sleeve ( 17 ) for receiving the treatment element ( 13 ) which can slide in relation to the sheath ( 15 ) between an expanded position for receiving the treatment element ( 13 ) and a compressed interposed position between the treatment element ( 13 ) and the sheath ( 15 ). The treatment element ( 13 ) is substantially axially fixed in relation to the receiving sleeve ( 17 ) when the sleeve ( 17 ) moves between its receiving and interposed positions. The kit can be used to insert endoprostheses into a blood vessel.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a kit for treating a blood circulation system, comprising:
         at least one implantable treatment element which can be radially deformed between a retracted state and a deployed state;   a sheath for holding the treatment element in its retracted state;   means for pulling the treatment element into the sheath;       

     The kit is used in particular for inserting endoprosthesis into a blood vessel. 
     2. Description of Related Art 
     Such a kit is disclosed in publication EP 0 472 731, in which an endoprosthesis in a deployed state is introduced into a sheath for maintaining said endoprosthesis in a retracted state. 
     The means for introducing the endoprosthesis into the sheath comprise a pull-wire at one end of the endoprosthesis and a funnel mounted to the end of the sheath which allows the endoprosthesis to contract when it is pulled inside the sheath by the string. 
     A device of this type is not entirely satisfactory. In fact, the wire must be pulled very firmly in order to pull the endoprosthesis into its sheath. The endoprosthesis must therefore be inserted into its sheath before the kit is packaged and not during a surgical operation just before the endoprosthesis is implanted. 
     An object of the invention is therefore to provide a kit for treatment of a blood circulation system in which a treatment element can be easily inserted, in particular during a surgical operation, into a sheath for maintaining said element in a retracted position. Furthermore, the kit must allow the treatment element to be easily extracted when it is implanted, thus limiting the risk of injuring the patient. 
     SUMMARY OF THE INVENTION 
     To this end, the invention relates to a treatment kit of the aforementioned type, characterised in that the introduction means comprise at least one sleeve for receiving the treatment element, which can slide in relation to the sheath between an expanded position for receiving the treatment element outside the sheath and a compressed interposed position between the treatment element and the sheath, the treatment element being substantially axially fixed in relation to the receiving sleeve when the receiving sleeve moves between its receiving and interposed positions, and in that the sleeve comprises at least one return strand curved back to the outside of the sheath, the introduction means comprising an element for pulling the curved strand, or each curved strand towards a proximal end of the sheath, the pulling element being able to slide along the sheath when the sleeve is displaced from its receiving position to its interposed position. 
     The kit according to the invention may comprise one or more of the following features taken in isolation or in any technically feasible combination:
         the receiving sleeve comprises a region for retaining an end of the treatment element and a region for guiding the treatment element when the retaining region is inside the sheath and the guiding region projects outside the sheath;   the treatment element is detachably fixed to the introduction means;   the introduction means form the means for extracting the treatment element from the sheath;   the receiving sleeve comprises at least two flexible prongs joined together by a common base and having free ends which are not connected;   the introduction means comprise an element for controlling displacement of the receiving sleeve in relation to the sheath, the controlling element and the receiving sleeve being integral;   the coefficient of friction between the receiving sleeve and the sheath is less than the coefficient of friction between the treatment element and the sheath;   the treatment element is an endoprosthesis comprising a deployable frame; and   the treatment element is a deployable valve;   the sleeve comprises, in its receiving position, an end for retaining the endoprosthesis, the pulling element being integral with a free end of the sleeve;   the pulling element comprises a collar slidingly mounted to the outside of the sheath;   the pulling element is connected in translation to the retaining end;   the pulling element is disposed in the sheath, the sheath comprising at least one lateral passage in which the free end of the sleeve is engaged; and   each flexible prong is curved around a distal region of the sheath delimited by a lateral passage and a distal end of the sheath.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood after reading the description which follows, given solely by way of example and with reference to the attached drawings, in which: 
         FIG. 1  is an elevation of a first packaged kit, for which a protection is not sought; 
         FIG. 2  is an elevation of the kit in a first position of the receiving sleeve; 
         FIG. 3  is a cross-section along a median plane of the kit in a second position of the receiving sleeve; 
         FIG. 4  is a view, similar to that of  FIG. 2 , of a second treatment kit for which no protection is sought; 
         FIG. 5  is an elevation of a third treatment kit for which no protection is sought; 
         FIG. 6  is a view, similar to that of  FIG. 2 , of the third treatment kit according to the invention; 
         FIG. 7  is a view, similar to that of  FIG. 3 , of a first treatment kit according to the invention; 
         FIG. 8  is a view, similar to that of  FIG. 3 , of a second treatment kit according to the invention; and 
         FIG. 9  is a partial perspective view of the sheath of the second kit according to the invention illustrated in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The treatment kit  11  illustrated in  FIG. 1 , which is not covered by the claims of this application, comprises a tubular endoprosthesis  13 , which can be deployed between a retracted state and a deployed state, a sheath  15  for maintaining the endoprosthesis  13  in its retracted state and means  19  for inserting the endoprosthesis  13  into the sheath  15  which comprise a sleeve  17  for receiving the endoprosthesis  13 . 
     The endoprosthesis  13  comprises a tubular wire-mesh  21  made of a metal which can be implanted, such as stainless steel, which has resilient properties. Thus, in the example illustrated, the endoprosthesis  13  is self-expanding. 
     As is known per se, the endoprosthesis  13  can spontaneously deform from its retracted state, in which it has a small diameter, to its deployed state, in which it has a greater diameter, said deployed state being its rest state. 
     In the illustrated example, the wire-mesh  21  of the endoprosthesis is embedded in an expandable film  23 , such as an elastomer, which is impervious to liquids. This elastomer could be, for example, a silicone. 
     An endoprosthesis of this type is generally denoted by the term “stent”. 
     The elements of the treatment kit  11  are packaged in the same packaging  25  formed of, for example, an airtight and watertight pocket. The endoprosthesis  13  is retained in its deployed state in said packaging  25 . 
     The sheath  15  is formed of a tube  27  made of plastics material, for example, polytetrafluoroethylene (PTFE), delimiting an inner tube  29  which has a diameter substantially equal to the diameter of a transverse section of the endoprosthesis  13  in its retracted position. 
     The sheath  15  extends longitudinally between a distal end  31  for insertion into a blood vessel and a proximal end  33  for surgical access. The end  31  has a divergent conical shape at its tip. However, in a variation, the end  31  is straight. 
     In the example illustrated by  FIG. 1 , the means  19  for introducing the endoprosthesis  13  into the sheath  15  are formed from a resilient tube  35  made of polytetrafluoroethylene (PTFE) in which there are arranged a plurality of longitudinal slits from the distal end of said tube  35 . 
     The tube  35  delimits, in its slitted part, the receiving sleeve  17  and, in its solid part, a cylinder  37  for controlling the movement of the endoprosthesis. 
     The receiving sleeve  17  of the endoprosthesis  13  comprises a ring  39  for retaining an end of the endoprosthesis  13  and a plurality of flexible guiding prongs  41 . 
     The retaining ring  39  is formed by the end of the solid part of the tube  35 . It has an outer diameter which is smaller than or substantially equal to the inner diameter of the sheath  15 . 
     The flexible prongs  41  extend from the retaining ring  39  to the free ends which are not connected. 
     The prongs  41  are laterally delimited by the slits arranged in the tube  39 . 
     The flexible prongs  41  are displaceable between a position at a distance from a central axis X-X′ defined by the ring  39  and a position next to said central axis X-X′. 
     The length of the flexible prongs  41  is at least substantially equal to the length of the endoprosthesis  13  in such a way that when an end of the endoprosthesis  13  is inserted into the ring  39 , the prongs  41 , in their position in the proximity of axis X-X′, extend in a manner substantially following the length of the endoprosthesis  13 . 
     The receiving sleeve  17  can slide in relation to the sheath  15  between a dilated position for receiving the endoprosthesis  13  outside the sheath  15 , in which the prongs  41  are disposed at a distance from the central axis X-X′, an intermediate position for inserting the ring  39  into the sheath  15  and a compressed interposed position in the sheath  15  between the endoprosthesis  13  and the sheath  15 . 
     In the intermediate position of insertion, illustrated by  FIG. 2 , the retaining ring  39  is inserted into the sheath  15 . The prongs  41  project at least partially outside the sheath  15  and have a shape which diverges substantially towards the outside of the sheath  15 . The prongs  41  are progressively compressed towards the axis X-X′ by being pressed against the peripheral region at the distal end  31  of the sheath  15 . 
     In the interposed position, illustrated by  FIG. 3 , the sleeve  17  containing the endoprosthesis  13  is substantially completely inserted inside the sheath  15 . The endoprosthesis  13  is maintained in its retracted state and the prongs  41  are flattened against the wire-mesh  21  of the endoprosthesis  13  by the internal wall of the sheath  15 . 
     The controlling cylinder  37  is longer than the sheath  15  in such a way that its proximal end  53  protrudes beyond the proximal end  33  of the sheath  15  when it is disposed in the sheath  15 . 
     The controlling cylinder  37  can slide inside the sheath  15  when pushed at its proximal end  53 . The controlling cylinder  37  thus also forms a means for extracting the endoprosthesis  13  from the sheath  15  during its implantation in a blood vessel, as described in more detail below. 
     In the illustrated example, the retaining ring  39 , the flexible prongs  41 , and the controlling cylinder  37  are integral. In a variation they are separate parts. 
     As an example, a method for preparing the endoprosthesis  13  for implantation in a blood vessel, from the kit  11 , according to the invention will now be described. 
     This method comprises a preservation phase and a preparation phase. 
     During the preservation phase, the endoprosthesis  13  is retained in the packaging  25  in its deployed state which allows the mechanical or morphological properties of the endoprosthesis  13  to be preserved, in particular when its tubular wire-mesh  21  is imbedded in a film  23  which is expandable and air and water tight. 
     In the preservation phase itself, which takes place just before implantation of the endoprosthesis  13  during a surgical operation, the surgeon opens the packaging  25  and cuts the endoprosthesis  13  lengthwise so that it matches the morphology of the blood vessel in which it is to be implanted. 
     Initially, the surgeon slides the controlling cylinder  37  into the sheath  15 . The sleeve  17  is disposed in its position for receiving the endoprosthesis  13 , in which the ring  39  and the prongs  41  of the receiving sleeve  17  project outside the sheath  15 . 
     The surgeon then inserts an end  61  of the endoprosthesis  13  into the ring  39  of the sleeve  17 , for example by pinching said end  61 . 
     The endoprosthesis  13  is then held in the ring  39  in a tight-fitting manner at the end of the controlling cylinder  37 . The prongs  41  face the frame  21 . 
     With reference to  FIG. 2 , the surgeon then pulls on the proximal end  53  of the controlling cylinder  37  and moves said end  53  away from the sheath  15 . The ring  39 , the prongs  41  and the endoprosthesis  13  thus slide into the sheath  15 . 
     During said displacement, the prongs  41  slide against the internal wall of the sheath  15  and prevent substantially all contact between said internal wall and the frame  21  of the endoprosthesis  13 . Due to the shape of the prongs  41  which diverge towards the exterior of the sheath  15 , the prongs  41  are progressively compressed towards the axis X-X′ by pressure on the peripheral region at the distal end  31  of the sheath  15 . This allows the endoprosthesis  13  to be progressively compressed from its deployed state to its retracted state, as illustrated by  FIG. 3 . 
     The presence of the receiving sleeve  17  when the endoprosthesis  13  is inserted into the sheath  15  substantially reduces the frictional force between the endoprosthesis  13  and the inner wall of the sheath  15 . The minimum traction that must be applied to the controlling cylinder  37  in order to insert the endoprosthesis  13  into the sheath  15  is thus substantially equal to the friction between the receiving sleeve  17  and the inner wall of the sheath  15 . 
     The ratio of the coefficient of friction between the endoprosthesis  13  and the inner wall of the sheath  15  and to the coefficient of friction between the receiving sleeve  17  and the inner wall of the sheath  15  is greater than 10 and is, in particular, between 10 and 100. 
     Thus, the traction to be applied to the introduction means  19  is considerably reduced and the endoprosthesis  13  can be inserted into the sheath  15  very easily. 
     In order to deploy the endoprosthesis  13  into the blood vessel, the surgeon implants a surgical guide (not illustrated) into the blood vessel or the vein and this runs from the external insertion point to the region of the vein or the artery where the endoprosthesis  13  is to be implanted. 
     The endoprosthesis  13  is maintained in its retracted position by the sheath  15  and is then inserted up to the point where it is to be implanted by means of displacement along the surgical guide. 
     Once the endoprosthesis  13  has been inserted, the surgeon deploys the distal end  63  of the endoprosthesis  13  into the vessel by pushing the controlling cylinder  37  in order to displace its proximal end  53  towards the sheath  15 . 
     The distal end  63  of the endoprosthesis  13  opens out outside the sheath by spreading open the flexible prongs  41  in such a way that the wire-mesh  21  moves close to the walls of the vessels to be treated and comes to press on said walls. 
     When the endoprosthesis  13  is extracted from the sheath  15 , the presence of the receiving sleeve  17  also substantially eliminates the friction between the endoprosthesis  13  and the sheath  15  which facilitates deployment of the endoprosthesis  13  into the vessel. 
     Once the distal end  63  of the endoprosthesis  13  has been settled against the walls of the vessel to be treated the surgeon proceeds with removing the sleeve  17  and the sheath  15  from the blood vessel. 
     In the variant illustrated in  FIG. 4 , the endoprosthesis  13  is mounted coaxially on a sole prop  101  and is fixed on said prop  101  by detachable retaining filaments  103 ,  105  of the type described in the French application No. 03 14424. 
     The filaments  103 ,  105  are engaged in the frame  21  respectively at the distal end  63  and proximal end  61  of the endoprosthesis  13  and form at these ends  61 ,  63  tightening loops, the length of which can be controlled by extensions of the filaments  103 ,  105  up to the proximal end of the prop  101 . 
     The diameter of the prop  101  is substantially smaller than the inner diameter of the sheath  15  and of the ring  39 . 
     Thus, during the preservation phase, the receiving sleeve  17 , the controlling cylinder  37  engaged in the sheath  15  and the endoprosthesis  13  in its deployed state are coaxially disposed on the prop  101 . 
     As disclosed in the cited French application, during surgery the surgeon starts by gripping the tightening loops at the ends of the wire-mesh  121  by pulling the extensions of the wires  103 ,  105  before bringing the endoprosthesis  13  into an intermediate retracted state. 
     Next, in order to insert the endoprosthesis  13  into the sheath  15 , the surgeon introduces the proximal end  61  of the endoprosthesis into the ring  39  then simultaneously displaces the proximal ends of the prop  101  and the controlling cylinder  37  away from the proximal end  33  of the sheath  15 . 
     The endoprosthesis  13  received in the sleeve  17  then penetrates the sheath  15  as previously described. 
     Once inside the sheath  15 , the endoprosthesis  13  has a cross-section with a minimal diameter along the whole of its length. 
     Its deployment into the blood vessel takes place as in the cited French application. 
     In a third variant illustrated in  FIGS. 5 and 6 , the kit comprises a heart valve  201  deployable between a retracted state and a deployed state. 
     During the preservation phase, the valve  201  in its deployed state is fixed at its converging end  203  to an introduction tube  205 . This fastening takes place, for example, with the aid of a retaining filament  207  which can be detached from the external point of insertion into the blood circulation system to be treated. 
     Unlike the first kit, the receiving sleeve  17  then the sheath  15  are coaxially mounted on the introduction tube  205  in such a way that the proximal end of said tube  205  projects beyond the sheath  15 . 
     In order to prepare the valve  201  for implantation, the surgeon slides the proximal end of the tube  205  at a distance from the proximal end  33  of the sheath  15  into the sheath  15  whilst keeping the receiving sleeve  17  substantially fixed in relation to the sheath  15  with the aid of the controlling cylinder  37 . 
     Displacement of the tube  205  allows the converging end  203  of the valve  201  to be introduced into the ring  39 . In this intermediate position, illustrated by  FIG. 6 , the flexible prongs  41  face the wire-mesh  209  of the valve  201  and thus have a shape which diverges substantially away from the sheath. 
     The surgeon then displaces the proximal end  53  of the controlling cylinder  37  away from the sheath  15 . The valve  201  being fixed in the ring  39 , the displacement of the proximal end of the tube  205  at a distance from the sheath  15  continues. The assembly formed by the valve  201  and its receiving sleeve  17  is then inserted into the sheath  15 . 
     Deployment of the valve  201  takes place as previously described for the endoprosthesis  13 , the last step consisting of detaching the retaining wire  207  from the valve  201  then removing the tube  205  from the blood circulation system. 
     It is therefore possible to provide a kit for treating a blood circulation system which allows simple insertion, requiring only a gentle pull, of a treatment element  13 ,  201  into a sheath  15  for maintaining said element  13 ,  201  in a retracted position. This insertion can take place easily during surgery. 
     Furthermore, the kit facilitates extraction of the treatment element  13 ,  201  from the sheath  15  during the implantation of said element in a blood circulation system. 
     This kit allows the treatment element  13 ,  201  to retain its deployed state and, if necessary, to be cut to size just before its implantation so as to match the length of the blood vessel in which it is to be implanted. 
     The first kit according to the invention, illustrated in  FIG. 7 , differs from the kit illustrated in  FIG. 3  with regard to the following characteristics. 
     The introduction means  19  (i.e., a pulling unit) of the endoprosthesis  13  into the sheath  15  comprise a rod  301  for controlling displacement of the receiving sleeve  17  engaged in the sheath  15  and a pulling collar  302  of the sleeve  17  mounted on the sheath  15 . 
     The rod  301  is equipped, at its proximal end, with a grip  303 , and at its distal end, with a piston  305  for pushing the endoprosthesis  13 . 
     The piston  305  is slidingly mounted inside the sheath  15 . 
     The retaining ring  39  of the endoprosthesis  13  formed in the receiving sleeve  17  is fixed on a distal surface of the piston  305 , opposite the rod  301 . 
     Each prong  41  of the sleeve  17  comprises a return strand  310  which projects outside the sheath  15 . The return strands  310  are curved back against the outer surface, denoted as  311 , of the sheath. 
     The free ends  309  of the prongs  41 , arranged opposite the retaining ring  39 , are fixed along a distal peripheral surface of the pulling collar  302 . 
     The collar  302  is slidingly mounted on an outer surface  311  of the sheath  15 . It is mobile along the sheath  15  between a proximal position of deployment of the endoprosthesis  13  into the sheath  15 , in which the collar is at a distance from the detached end of the endoprosthesis, and a distal position which it is in when the endoprosthesis  13  is completely inserted into the sheath  15  and in which the collar is nearer to the releasing end. 
     The collar  302  further comprises guiding means (not illustrated) which prevent the collar from rotating about the longitudinal axis of the sheath  15 . 
     The length of the prongs  41  is at least three times greater than the length of the endoprosthesis  13  in such a way that the collar  302 , in its proximal and distal positions, remains outside the patient&#39;s body. As for the rest, the features of the first kit according to the invention are similar to the features of the first kit described in  FIGS. 1 to 3 . 
     Initially, in order to insert the endoprosthesis  21  into the sheath  15 , the piston  305  is disposed in the proximity of the distal end  31  of the sheath. The retaining ring  39  is thus arranged in the sheath  15  in the proximity of the distal end  31 . The collar  302  is maintained in its proximal position. The position of the collar  302  is adjusted manually by pulling it towards the proximal end  33  of the sheath  15  so the return strands  310  of the prongs  41  are flattened on the outer surface  311  of the sheath. The maximal transverse dimension of the kit is therefore reduced. 
     Next, the proximal end  61  of the endoprosthesis  13  is inserted into the retaining ring  39 . The piston  305  is thus displaced towards the proximal end  33  of the sheath  15  by using the grip  303 . 
     At the time of this displacement, the prongs  41  and the endoprosthesis  13  penetrate the sheath  15 . The prongs  41  interpose between the endoprosthesis  13  and the sheath  15 . Furthermore, the collar  302  is pulled towards its distal position by the guiding prongs  41 . 
     In order to deposit the endoprosthesis  13  inside the patient, the surgeon simultaneously moves the grip  303  towards the distal end  31  of the sheath  15  and the collar  302  towards the proximal end  33  of said sheath  15  to pull the return strands  310  of the prongs  41  towards the end  33 . 
     Thus, the prongs  41  are flattened against the outer surface  311  of the sheath  15 , which limits the risk of injuring the patient during deployment of the endoprosthesis, in particular by tearing the wall of the blood vessel. 
     In another variant, the first kit according to the invention may include the characteristics of the kit in  FIG. 4  or of the kit in  FIGS. 5 and 6  with the exception of the flexible prongs  41  which are curved back to the outside of the sheath. 
     The second kit according to the invention, illustrated in  FIG. 8 , differs from the kit illustrated in  FIG. 7  with regard to the following characteristics. 
     As illustrated in  FIG. 9 , the sheath  15  comprises a plurality of transverse passages  321  arranged in the lateral wall of the sheath. These passages  321  extend substantially along the periphery of a transverse section of the sheath  15 . The distance between the distal end  31  and the passages  321  is greater than the length of the endoprosthesis  13 . 
     The number of passages  321  is equal to the number of prongs  41 . Furthermore, the width of the passages  321 , taken from along the periphery, is substantially equal to the width of the prongs  41 . 
     The free ends  309  of prongs  41  are engaged through the passages  321  and are fixed on a proximal surface of the piston  305 . 
     The piston thus forms a means for pulling the return strands  310 . 
     The length of the prongs  41  is designed to be substantially equal to two times the length which separates the proximal end  31  of the passages  321 . The return strands  310  of the prongs  41  arranged outside the sheath  15  are therefore flattened on the outer surface  310  of the sheath  15 . 
     Each prong  41  is curved around a distal region  325  of the sheath  15  delimited by a passage  321  and the distal end  31 . Each prong  41  forms, around this region, a conveyor band for inserting the endoprosthesis  13  into the sheath  15 . 
     Thus, in order to insert the endoprosthesis  13  into the sheath  15 , the ring  39  is placed at the distal end  31  of the sheath  15  by displacement of the piston  305 . Then, the proximal end  61  of the endoprosthesis  13  is inserted into the ring  39  and the piston  305  is displaced towards the distal end  33  of the sheath  15 . 
     Deployment of the endoprosthesis  13  takes place by displacing said piston  305  towards the proximal end  31  of the sheath  15 .