FR2694699A1 - Appts. for introducing blood filter into vein - comprises long and short fibres embedded in plug and inserted into catheter via coaxial cones and piston - Google Patents

Abstract

Appts., comprising long and short elastic fibres (3,4) connected at one end by cylindrical plug (n/s), has the means of progressively and successively regrouping the threads via adjacent coaxial conical surfaces (10,11,12) with increasing angles of conicity (13,14,15) by pressure on the plug. The filter is composed of fibres (3,4) of different lengths, the longer fibres (4) being twice the length of the shorter fibres (3). Each fibre is curved towards the exterior and the ends of the longer fibres (4) are curved towards the interior. USE/ADVANTAGE - Introduction of blood filter to human or animal circulatory systems. Stable and precise positioning in vein. Low cost. Low number of components of appts. reduces manipulation by surgeon. Sterility maintained.

Description

BLOOD FILTER AND ITS INTRODUCING DEVICE
The present invention relates to a blood filter intended to be introduced into the blood circuit or network of a human or animal and to a device for introduction into the blood circuit specially adapted for this type of filter.

 The technical field of the invention is that of the manufacture of filters intended to be implanted in the human body.

 We already know different types of blood filters intended to be introduced and placed in a vein in particular for the purpose of preventing the progression of clots, and introduction devices adapted to such filters.

 Patent application EP-270432 (PROMED) describes a filtering device comprising a filiform body extended at one of its ends by a first filter constituted by flexible diverging wires and comprising at 11 other end of the body, a stabilizer acting as second filter consisting of several flexible wires diverging around the body.

 According to this document, the filter is housed in the folded state in a catheter capable of being introduced into the jugular vein and inside which is disposed a cannula which can be immobilized when the catheter is removed to release the filter which is deploys in the vein and whose points come to hang and / or lean against the internal wall of the vein.

 Patent application FR2649884 (EMS INDUSTRIES) describes a blood clot retaining filter comprising several elastic branches regularly arranged around the axis of a central core connecting these branches, some of the branches comprising a hook at their ends. anchoring in the wall of the vein.

 This document describes a method of fitting the filter into the vein which comprises the following steps: the filter is fitted with a plastic sleeve, the non-entanglement of the branches of the filter is checked by sliding the sleeve from side to side. 'Other of the core, the filter is introduced after replacing the sleeve around the core in a cylinder comprising a conical recess extended towards the catheter by a tubular part shaped to be introduced into the catheter.

 Patent US4425908 (SIMON) describes a blood filter comprising a plurality of wire portions; this document relates to a filter which can be folded radially to be inserted via a catheter, which is made of a relatively flexible and pliable material at a low temperature, which material regains a predetermined shape at a high temperature in which the material is relatively stiff; the filter can consist of 7 wires of a nickel and titanium alloy which are held together by an end sleeve and a central sleeve, and can constitute when the wires are deployed radially a double filter, part of which has legs whose ends are free and which may be of different dimensions.

 This filter can be introduced into a catheter via a small diameter storage tube into which the filter is folded, and into which it can be introduced by traction.

 Patent US3334629 (COHN) describes another type of device for restricting blood flow and its introduction device.

 The object of the present invention is to provide a blood filter and its device for introduction into the blood circuit which are improved compared to known devices; indeed one of the significant drawbacks of the known devices is the large number of parts which must be handled by the surgeon in order to introduce the filter into the blood circuit; moreover, and correlatively, the sterility conditions of the filter cannot be achieved in the known devices because of the numerous manipulations which must be carried out manually and which do not make it possible to absolutely guarantee the sterility of the filter when it enters the filter. inside the introducer catheter.

 Furthermore, the very important problem solved by the invention is to avoid any possibility of tangling the legs constituting the filter; an objective of the invention also consists in providing a filter adapted to this type of introduction device and to these particular conditions of introduction and which also makes it possible to obtain positioning (and resistance over time) of the filter in the vein, as stable and precise as possible; another object of the invention is to provide such filters and such filter insertion devices at reduced costs and comprising a reduced number of parts.

 The solution to the problem posed consists in providing an introduction device which comprises a sealed container capable of containing a filter for the purposes of sterile storage, for example, the filter being disposed substantially in the container in the deployed state, said device comprising means introducing the filter into a catheter by pushing on the filter tip (to which the tabs are fixed by one of their ends) and comprising means for progressive and successive grouping of the filter tabs which are preferably of different lengths; according to an essential characteristic of the invention, said introduction device comprises a piston means comprising on the one hand means for centering or guiding the end piece of said filter during a translation inside the container of generally general shape cylindrical, and further comprises means for guiding in translation of said piston inside said container, and which finally comprises means allowing the escape (towards the outside of the container) of an inert fluid initially contained in said container waterproof for the purpose of storing said filter, when it is pushed onto said filter.

 According to an essential embodiment of the invention, said means for progressive and successive grouping of the legs of the filter comprise a plurality of coaxial and adjacent conical surfaces making it possible to ensure said progressive grouping of said legs and this successively (ie all first of the longest leg, then of the shorter ones).

 The solution to the problem also consists in providing a blood filter intended to be introduced into the human body or that of an animal, consisting of several elastic filiform legs of different length, joined at one of their ends by a nozzle, which legs are 'extend from a single (same) side of said tip, which comprises among said filiform elastic legs, first short legs of different neighboring lengths of a first length L, and which comprises second long legs of different neighboring lengths of a second length M close to double (that is to say whose ratio to said first length L is greater than or equal to 1.5 and less than or equal to 3) of said first length, and in which said long legs comprise a first part curved outwards and comprises a second part (extending said first part) which is curved inwards, and in s which said short legs mainly have an outwardly curved part, each of said legs being constituted by a section of curvilinear wire, each of said legs being fixed only by one of its ends by an embedding (for example produced by crimping) in said mouthpiece.

 According to a preferred embodiment of the invention, said device for introducing, via a catheter 9 (of small diameter, into the blood system or network of the body of a human or animal) of a filter blood (for example intended to be implanted in the vena cava) comprising several filiform elastic legs joined at one of their ends by a generally substantially cylindrical tip (which legs extending on the same side of said tip), which device comprises means for grouping (or assembling or joining) said legs (along said axis XX1 so that said filter provided with said grouped legs fits in a cylinder of diameter substantially equal to the internal diameter of said catheter), which legs are of different lengths, in which said grouping means comprise several (at least 2) adjacent coaxial conical surfaces whose respective opening angles s have different values (increasing as a function of the average distance of said surface from the end of said catheter into which said filter is to be inserted) so as to cause successive progressive deformations for each of said legs, and said means of introduction allow by a push on said tip, a grouping by elastic deformation of the longest legs followed by a grouping of shorter legs, and allow the successive introduction into said catheter of the longest legs followed by the shorter legs, they -same followed by said tip.

 Advantageously, said filter comprises first legs of a length close to a first length (L) and comprises second legs of length substantially different from each other but close to a second length (M) (whose value is for example close double the value of said first length (L)), and wherein the number of said second legs is equal to the number of said conical surfaces.

 Advantageously, said number of said second legs and of said conical surfaces is greater than or equal to three, and said number is less than or equal to six.

 Advantageously, said long legs (second legs) have a first part curved outwards according to a radius R1 and comprises a second part extending said first part (away from said end piece) which second part is curved inwards according to a second radius R2.

 Advantageously, said short legs (or first legs) have a main part curved outwards according to a third radius R3.

 Advantageously, said endpiece comprises a tubular body of cylindrical section closed at a first end and open at a second end, which endpiece defines a substantially cylindrical cavity of diameter less than its length, inside which said ends of said legs can be immobilized by a central crimping key, of substantially cylindrical shape.

 Advantageously, said conical surfaces have an axis revolution (XX2), and a straight generator.

 Advantageously, said angles have respective values close to 30, 45 ", 600 (to within 150).

 Advantageously, said short legs (or first legs) have lengths whose ratio to the average length (L) of said first legs is greater than or equal to 0.9 and said ratio is less than or equal to 1.1.

 Advantageously, said long legs (or second legs) have lengths whose ratio to the average length (M) of said second legs is greater than or equal to 0.9 and said ratio is less than or equal to 1.1.

Advantageously, said first legs in the deployed state (or free state) are contained in a cylinder with axis (XX1) and radius
R5, and said second legs in the deployed state are contained in a cylinder with axis (XXl) and radius R4, and said radius R4 is less than said radius R5.

 Advantageously, said introduction device comprises a cylindrical body of circular section having for axis said axis (of revolution) of said conical surfaces, the internal radius of which is substantially less than said radii R4 and R5 of said cylinders in which said first and second legs are inscribed. in the deployed state, so that said filter can be easily positioned manually inside said cylindrical body of said introducer, by slight deformation of said first and second tabs, and so that said filter is then held in a substantially coaxial position with said cylindrical body through the reaction of said elastic tabs bearing on the inner wall of said cylindrical body.

 Advantageously, said cylindrical body is partly at least transparent or translucent.

 Advantageously, said cylindrical body is fixed (preferably by interlocking) rigidly (or irremovable) with an insertion piece comprising said conical surfaces.

 The numerous advantages provided by the invention will be better understood through the following description which refers to the accompanying drawings, which illustrate without any limiting character embodiments of the device according to the invention.

 Figure 1 illustrates in longitudinal section a filter according to the invention.

Figure 2 is a view along II.II of Figure 1 and constitutes a cross section of a filter nozzle according to the invention
FIG. 3 illustrates in longitudinal section a device for introducing a filter according to the invention.

 FIG. 4 illustrates a washer of a pusher or piston of an introduction device making it possible to ensure said centering or guiding means during translation of the piston in said body of the introduction device and also making it possible to ensure said means for leaking outwards from the body of the device, from the fluid initially contained and in which the filter has been conditioned inside said introduction device.

 With reference to FIG. 1, it can be seen that said filter is constituted by several first legs 3, which are relatively short, the protruding length of which being extended, measured relative to the open end 7c of a nozzle 7 (marked L) , is significantly less than the length (marked M) of second long legs 4, all of said first legs 3 and second legs 4 being held by their respective ends 5, 6 substantially rectilinear, inside a cylindrical recess 22 provided in said end piece 7, thanks to a central key 8 for crimping said tabs in said cylindrical end piece.

 Said nozzle is closed at one end 7b in which it can take on a substantially hemispherical shape.

 In the zone for fixing said legs by said end piece and said key, it can be seen that said ends 5 and 6 of said legs, said key 8 and said end piece 7 extend along a common axis XX1.

Said first legs 3 are advantageously provided at their free end 19 with a relatively tapered tip and oriented towards the outside of a fictitious cylinder having for axis said axis XX1 and of radius R5, inside which said first legs 3 are inscribed said first legs 3 or inking legs of said filter in the vein are curved outward substantially along a radius R3 and a center of curvature C3 preferably located outside of said cylinder of radius R5
Said second legs 4 comprise a first part, near the open end 7C of said end piece, which is curved outwards according to a radius of curvature Ri and a center of curvature C1, which first part of said second legs 4 is extended by a second part curved towards the inside of a fictitious cylinder having for axis said axis XX1 and of radius R4 which may advantageously be slightly less than said radius R5; said second part of said legs 4 can be curved along a radius R2 and a center of curvature C2 located inside said cylinder of radius R4; said second legs can be folded at their free ends 20 in order to avoid any injury by contact of said end with the interior wall of the vein.

 With reference to FIGS. 1 and 2, it can be seen that advantageously said first legs 3 (marked 31 to 36 in FIG. 2) and said second legs 4 (marked 41 to 43 in FIG. 2) are distributed angularly uniformly inside the tubular cylindrical housing 7a forming part of said end piece 7, around said key 8 for crimping said ends of said lugs inside said end piece.

 With reference to FIG. 3, it can be seen that said device 1 for introducing said filter 2 comprises a part acting as a storage container for said filter, which part essentially comprises a cylindrical body 23 with an internal radius R6 advantageously very slightly less than said radius R4 and R5 outside of said deployed tabs of said filter so that said filter self-maintains inside said cylindrical body 23 during the storage period, said filter being moreover centered and / or maintained by its endpiece (item 7a, 7b, 7c of FIGS. 1 and 2) thanks to a cavity 26 which conforms substantially to the external shape of said end piece and provided at the end of a piston 25.

 It can be seen that said piston 25 which can slide inside said cylindrical body 23 along the axis XX2 of general symmetry of said body (and of said introduction device) comprises (on the right in FIG. 3) a substantially massive and cylindrical part of R'6 slightly smaller than said radius R6 so as to allow the free passage of a fluid between the cylindrical outer wall of said piston and the cylindrical inner wall of said body 23, this leakage of fluid previously contained in the cavity 29 delimited in particular by said body 23 making it possible to avoid overpressing said cavity 29 during the thrust exerted on the rear face 33 of said piston 25 this thrust causes a translational movement of said piston and of said filter allowing the legs of said filter 2 to be grouped together, so as to to pass it from a substantially deployed state to a grouped state (folded along the axis XX2 of said device) and authorizing it to penetrate trer in the channel 21 for introduction into a catheter 9 and thus allowing its introduction into the human body in particular.

 It can also be seen in this figure that said piston preferably comprises means for guiding in translation 30 which can for example be produced by a washer as illustrated in FIG. 4, which has a substantially cylindrical external contour 31 ensuring the guiding function of the piston in said cylindrical body 23, and a part of the contour being cut so as to produce flats 32 allowing the leakage of said fluid towards the outside of said cavity 29 of said device during the insertion of said piston into said cylindrical body 23.

 It can also be seen in this FIG. 3 that said device preferably comprises rigidly connected to said body 23, a part 24 for introduction of a general form of revolution of axis XX2 endowed with an internal pipe 21 through which said introduction part is connected to said catheter 9, said channel 21 being connected to said cavity 29 for storing said filter in said cylindrical body 23, by a cavity 28 for grouping the legs of said filter, which cavity 28 is delimited by 3 adjacent coaxial conical surfaces 10, 11 , 12, of respective angles at the center (or opening angle) 13, 14, 15.

 We see that said conical surfaces 10, 11, 12 allow the connection of said cylindrical cavity 29 of radius R6 to said cylindrical channel 21 of diameter D1 adapted to the diameter D2 of said catheter 9, by conical slopes of successive rectilinear generators, which make it possible to pass , in the direction of movement of said filter during its introduction into the catheter, of a radius R7 substantially equal to said radius R6, to a radius R8 corresponding to the circular contact area between said surfaces 12 and 11, then to a radius Rg corresponding to the circular contact area between said surfaces 11 and 10, to end in a radius corresponding to said diameter D1 of said channel 21.

 It has in fact been discovered, particularly in the case of a filter using legs of different lengths, in particular filters using a first set of long legs of different lengths but close to one length (reference M in FIG. 1) and d 'a second set of hooking lugs of different lengths but close to an average length of second legs (reference L in Figure 1), that the introduction of this type of filter into a catheter posed a problem of entanglement of said legs which it is imperative to solve and which is solved thanks to the invention by the progressive evolution of the opening angles of the conical surfaces, which allows progressive grouping for each of the legs, that is to say a progressive deformation of each of said legs until bringing it into a substantially rectilinear position and close to the axis XX2 of the device, and so as to successively ensure this deformation for the 'all of said legs.

 It should be noted that this type of introduction device, in order to be waterproof during the period of use as a filter storage means, can advantageously be provided on its rear face 23a with a safety screen such as a film bonded to said face 23a in order to ensure this seal, and also to be closed at the end (left in FIG. 3) of said channel 21.

 Advantageously, said body 23 comprises in the rear part (located near said rear face 23a) of its internal face, a circumferential groove capable of receiving a stop means allowing the retention of said piston in said cylinder body, which stop means is for example in the form of a crown (or torus) or portion of a crown, of the "circlip" or stop ring type 34; this allows in particular during storage or transport periods to maintain said piston in a position where said filter is in contact (rests) by said tabs on said conical surfaces, and thus wedge these parts inside the device.

Claims (10)

 1. Device (1) for introduction via a catheter (9) of a blood filter (2) comprising a plurality of filiform elastic legs (3,4) joined at one of their ends (5,6) by a cylindrical end piece (7) with an axis (XX1), which device comprises means for grouping said legs, which legs are of different lengths, which grouping means comprise several adjacent coaxial conical surfaces (10, 11, 12) whose angles respective opening (13, 14, 15) have different increasing values (15> 14> 13), which device comprises introduction means which allow by a push on said nozzle, a progressive and successive grouping of said legs.  2. Device according to claim 1 characterized in that said filter comprises first legs (3) of a length close to a first length (L) and comprises second legs (4) of length close to a second length ( M) and in that the number of said second legs is equal to the number of said conical surfaces.  3. Device according to claim 2 characterized in that said number of said second legs and said conical surfaces is greater than or equal to three, and in that said number is less than or equal to six.  4. Device according to any one of claims 1 to 3 characterized in that it comprises a sealed container comprising said means for successive and progressive grouping of said tabs, means for pushing said filter towards said grouping means, which means for pushing comprise a piston provided with leakage means and means for guiding in translation.  5. Device according to any one of claims 1 to 4 characterized in that said conical surfaces are of axis revolution (XX2), and of straight generator.  6. Device according to any one of claims 1 to 5 characterized in that it comprises a cylindrical body (23) of circular section having for axis said axis of said conical surfaces, whose internal radius is substantially less than the radius R4 and R5 cylinders in which said first and second legs are inscribed in the deployed state, so that said filter can be easily positioned manually inside said cylindrical body of said introduction device, by a slight deformation of said first and second legs , and so that said filter is then held in a position substantially coaxial with said cylindrical body thanks to the reaction of said elastic tabs bearing on the inner wall of said cylindrical body.  7. Device claim 6 characterized in that said cylindrical body (23) is rigidly fixed with a part (24) of introduction comprising said conical surfaces.  8. blood filter intended to be introduced into the human body or that of an animal by an introduction device according to any one of claims 1 to 7, constituted by several elastic threadlike legs of different length, joined to one of their ends by an endpiece, which legs extend on one side of said endpiece, which filter comprises among said filiform elastic legs first short legs of different lengths close to a first length (L), which filter comprises second long legs of different lengths close to a second length (M) close to twice said first length, which long legs have a first part curved outwards and have a second part curved inwards, which short legs mainly have a part curved outwards, each of said legs being constituted by a section of core wire vilinear and being fixed only by one of its ends by a recess in said end piece.  9. Filter according to claim 8 characterized in that said end piece (7) comprises a tubular body (7a) of cylindrical section closed at a first end (7b) and open at a second end (7c), which end piece defines a cavity ( 22) substantially cylindrical with a diameter less than its length, inside which said ends (5, 6) of said tabs can be immobilized by a central crimping key (8), of substantially cylindrical shape.  10. Filter according to any one of claims 8 to 9 characterized in that said first legs in the deployed state are contained in a cylinder of axis (XX1) and radius R5, and in that said second legs to l deployed state are contained in a cylinder with axis (XX1) and radius R4, and in that said radius R4 is less than said radius R5.