FR2580504A1 - Filter for partial and at least temporary interruption of a vein and catheter carrying the filter - Google Patents

Abstract

The invention relates to a filter for partial and at least temporary interruption of a vein, and in particular of a lower vena cava of a human being. The filter comprises a plurality of branches 2 connected together at one of their ends, and which are contiguous at rest. It is characterised in that it comprises means such as a balloon 8 for spreading out the branches 2 of the filter 1 reversibly in the manner of the branches of an umbrella. The filter is mounted at the distal end 13 of a catheter whose proximal end is outside the body of the patient, the catheter allowing the inflation of the balloon, and possibly the infusion of therapeutic substances, to be controlled from a distance. Application to the medical equipment industry.

Description

 The invention relates to a filter for partial and at least temporary interruption of a vein and to a catheter carrying the filter.

 In particular but not exclusively, the invention relates to the partial and temporary interruption of the inferior vena cava in a human being, with the aim of preventing a pulmonary embolism or a recurrence.

 Partial or permanent interruption of the inferior vena cava is currently routinely performed during phlebitis to retain blood clots and prevent their migration to the pulmonary artery where they would cause embolism.

 Different techniques have been developed to date and for example one of them consists in ligating the vena cava so as to permanently interrupt the circulation of blood there.

 Another similar solution consists in partially interrupting the circulation of blood in the inferior vena cava by partial ligation, in particular by means of a clip known as a clip "ADAMS WEESE" or "MILES".

 These two techniques give fairly good results but they have the major drawback of requiring general anesthesia for the patient, which is sometimes not very compatible with their state of health, especially when they have just had a pulmonary embolism.

 To overcome this drawback, in recent years techniques have been developed which make it possible to implant a filter under the patient's local anesthesia into the inferior vena cava, with access to the internal jugular vein or the femoral vein.

Mention may be made, for example, of techniques which use filters for partial and final interruption of the inferior vena cava known under the name of "MOBIN parasol
UDDIN "and KIMRAY GREENFIELD filter.

 The umbrella of "MOBIN UDDIN" includes six radial branches which are connected by a perforated membrane and it can be placed under local anesthesia through the internal jugular vein (CLINICAL RADIOLOGY, 1982, vol 33, 577-583).

 Observations have however shown in the patient treated with this technique a significant frequency of early or late thrombosis of the inferior vena cava.

 In addition, the sharp points of the branches of the umbrella give it a traumatic character and are responsible for perforations and retro-peritoneal hematomas and prohibit the use of fibrinolytics.

The KIMRAY GREENFIELD filter (SURGERY, GYNECOLOGY,
OBSTETRICS, vol 156, Feb 83, 217-219) is made up of a plurality of sinuous branches joined at their summits.

 The filter is preferably brought by the jugular vein into the inferior vena cava or it is released which causes the deployment of its branches whose end comes to bear against the wall of the vein or relatively significant risks of migration pulmonary.

 This filter gives good results but has the disadvantage of not sufficiently preventing recurrent pulmonary embolism mainly for patients with a megacave, that is to say a lower vena cava whose diameter is greater than twenty eight millimeters.

 In addition, the efficiency of the filter for capturing short emboli is less good if the filter is not centered inside the vein.

 There are also more recent techniques which operate percutaneously and which use partial interruption filters known as the Bird's Nest filter and the SNITINOLS filter (RADIOLOGY, vol 150, 1984, 255-257 and RADIOLOGY , vol 145, Nov 1982, 351-355).

 These last two techniques use a fiber entangled on itself in an anarchic or ordered spiral manner, which thus constitutes a filter.

 All the techniques previously described generally have the drawback of causing a partial or total interruption of the inferior vena cava which is definitive, that is to say that it is not possible, except by surgical intervention. , remove the filter from the vein.

 In addition, if they do not allow #to simultaneously implement a therapeutic treatment by infusion (continuous infusion) for example of fibrinolytic substances in the filter area or generally.

 Faced with these techniques, the invention provides a filter for the partial and temporary interruption of the inferior vena cava, that is to say a filter which is intended to remain for a defined time in the vein and which partially interrupts its circulation. way to retain and trap clots.

 In this area, an occlusive balloon is known which is at the experimental stage and which allows a temporary interruption of the vena cava, but complete, ie a total interruption of the blood circulation.

 One of the aims of the present invention is therefore to propose a filter for the partial and temporary interruption of a vein, in particular of the inferior vena cava, which can be put in place then removed from the vein and which therefore , is preventive in nature, much more marked than existing filters, particularly with regard to pulmonary embolism.

 Another object of the present invention is to provide a filter which allows, simultaneously with its implantation, a treatment by infusion of therapeutic substances in the area of the filter or generally.

 Another object of the present invention is to provide a filter which centers itself in position inside the vein and which adapts not only to its nominal diameter but also to its temporary variations in diameter.

 Another object of the present invention is to provide a filter which has no traumatic characteristics for the wall of the vein.

 Another object of the present invention is to provide a catheter carrying the filter which enables it to perform these various functions.

 Other objects and advantages of the present invention will become apparent from the following description.

According to the invention, the filter for the partial and at least temporary interruption of a vein and in particular of the inferior vena cava of a human being, comprises a plurality of branches
hoses linked to each other at their proximal end, and extending at rest approximately parallel to each other
to the others, according to the generatrices of a cylinder, to their distal end.

It is characterized by the fact that it comprises deformable means for reversible expansion of the branches, remotely controllable, which are located inside the cylinder defined by
the branches at rest and which, by deformation, exert on the
branches a push from the inside which deploys them like the branches of a parasol, of sufficient amplitude
so that each branch is applied by deformation in its distal area against the wall of the vein.

The catheter carrying the filter has a length
sufficient for its distal end extended by the filter to be located at the level of the vein to be partially closed, in particular of the inferior vena cava, and for its proximal end to be outside the patient's body.

 The catheter comprises a slender conduit capable of sliding longitudinally inside an external sheath of introduction, in the distal end of which the branches of the filter are capable of being housed in the folded state.

 It is characterized in that it comprises reversible means for controlling from its proximal end the deployment of the branches and for adjusting the amplitude of said deployment.

The invention will be better understood with the aid of the description which follows, by way of nonlimiting example, with reference to the attached drawing, which represents schematically
- Figure 1: a partial side view of a filter connected to the distal end of a catheter,
FIG. 2: a front view of the filter of FIG. 1,
- Figure 3: a side view of the proximal end of the catheter,
- Figures 4, 5 and 6: an illustration of the different phases of the placement of the filter inside a vein.

 In the description, the qualifiers "proximal" and "distal" will be used, taking as a reference the area of the patient's body where the filter is introduced. Thus the distal end will be the most distant end of this zone and the closest proximal end.

 Referring to FIGS. 1 and 2, the filter 1 comprises a plurality of flexible branches 2 which are linked together at their proximal end 3, and which at rest extend approximately parallel to one another along the generatrices of a axis revolution cylinder 5.

 For example, the branches 2 are assembled at their proximal end 3, at the periphery of the end of a conduit 15, whose role will be described later.

 At this level, they are for example engaged in the radial notches of a ring, which encloses the conduit 6 at its end, and fixed in these notches by a clip, or by other means.

 Advantageously, at this level the filter comprises a marking ring 7, which is radiopaque, and which makes it possible to determine the position of the filter in the human body with the usual means of investigation.

 Optionally, it is this marking ring which assures the branches 2 on the conduit 6.

 Of course, any other suitable arrangement is suitable.

 The filter also includes deformable means for expanding the branches, which are remotely controllable.

 These means are located inside the cylinder defined by the branches 2 at rest and exert by deformation a thrust on the branches from the inside which deploy them in the manner of the branches of an umbrella.

 In FIGS. 1 and 2, these means are shown diagrammatically in the form of an expandable balloon 8, inflatable at a distance, which is located inside the cylinder defined by the branches 2 between their proximal end 3 and their distal end 4, preferably in the vicinity close to the proximal end 3.

 For example, as can be seen in FIG. 1, the balloon 8 is mounted on the end 6 of the conduit 15 downstream from the branch assembly zone 2.

 Preferably, the end 6 of the conduit 15 passes right through the balloon 8 longitudinally, so that, by inflation, the latter expands mainly radially.

 The inflation of the balloon 8 causes the deformation of the branches 2 which allows their great flexibility, and moreover the amplitude of deployment of the branches 2 varies according to the inflation of the balloon.

 This amplitude will be described later, but as of now, it is possible to specify that it is sufficient for at least the distal zone 10 of the branches 2, that is to say the zone of their distal end, to apply. against the wall of the vein, and deform in contact with it, so as to match its shape.

 It should be emphasized that the deflation of the balloon 8 causes the branches 2 which fold back into a position where they are substantially parallel to each other, around the axis 5.

 As for the balloon, it retracts between the end 6 of the conduit 15 and the internal wall of the branches 2.

 Any suitable number of branches is suitable, but preferably there are eight of them, and they are distributed forty-five degrees from each other around axis 5.

 In the proximal zone 11, that is to say behind the distal zone 10 which has been discussed previously, the branches are connected together by at least one flexible filament 12, so as to constitute, in the proximal part of the filter , a mesh capable of trapping any clots.

 The filament 12 is linked to the branches 2 in their proximal zone 11 by any suitable means, and in a preferred embodiment, the proximal zone 11 of the branches 2 is pierced with orifices in which the filament 12 is threaded by passing successively through 'one branch to another.

 In addition, preferably, the filament 12 is single, and it is threaded successively into the orifices of the branches 2 by describing a spiral which closes towards the balloon 8.

 The filament 12 can slide inside the orifices of the branches 2, which facilitates the installation of the filter inside a vein, - and its adaptation not only to the nominal diameter of the vein, but also to its distensions.

 The filter 1 is carried by a catheter, the distal end 13 of which is visible in FIG. 1 and the proximal end 14 is shown schematically in FIG. 3.

 The catheter carrying the filter 1 mainly comprises a flexible longitudinal duct 15 on which are assembled the proximal ends 3 of the branches 2 in the area 6 and the balloon 8 at its end.

 The duct 15 has a sufficient length so that its distal end is located at the level of the vein or the filter 1 must be implanted, for example the inferior vena cava, and that its proximal end is located outside the patient's body, this being able to be done using for example the jugular vein or the femoral vein.

 The duct 15 can slide over a large part of its length inside a sheath 16, the distal end 17 of which has sufficient internal dimensions for the filter 1 to be housed therein in the folded state, in particular during the introduction of the filter into the vein.

 Preferably, the sheath 16 is slit longitudinally or optionally pre-slotted.

 In this way, after introduction and placement of the filter in the vein, it is possible to remove the sheath 16 entirely by sliding it along the duct 15 inside the patient's body and opening it along from its slit on the outside.

 This is illustrated schematically in Figure 3.

 The proximal end 18 of the conduit 15 located outside the body of the patient, further has a sealing latch 19 through which the various pipes which pass through this conduit to the filter area.

 The conduit 15 has means for reversibly controlling from the proximal end of the catheter the expansion of the branches 2 of the filter 1, that is to say the inflation of the balloon 8 in the case of the filter shown in the figures.

 These means consist, in this case, in a pipe 20 which runs through the conduit 15, opens to # the interior of the balloon 8, for example through an orifice shown diagrammatically at 21, and the proximal end of which presents means diagrammatically shown at 22 to inject into the balloon 8 a fluid causing it to swell or to aspirate this fluid.

 It may for example be a piston pump which injects a liquid into the balloon or which sucks it according to the movement of the piston.

 The conduit 6 also advantageously has at least one pipe 23, which allows from the proximal end of the catheter to inject directly into the vein at the level of the filter 1, therapeutic substances.

 The duct 23 preferably opens out, at the distal end of the duct through two orifices 24, 25 located one inside the mesh of the filter 1, and the other of smaller dimensions outside the mesh in back of the filter.

 Thus, the orifice 24 is located on the axis 5 in the extreme part of the end 9 of the conduit 15 beyond its crossing of the balloon right through.

 The orifice 25 is located on the other side with respect to the proximal ends 3 of the branches 2 and opens, for example, at the periphery of the conduit 15 at a point, or possibly several distributed over this periphery.

 On the side of the proximal end of the pipe 23 is located means such as for example a three-way tap shown diagrammatically at 26, which allows in particular the infusion into the vein temporarily or continuously of fibrinolytic substances, and rinsing by means heparin serum.

 Line 23 therefore advantageously makes it possible to combine a partial and temporary obturation of the vein with the infusion in the zone of the filter of therapeutic substances, for example fibrinolytics, which is not possible with the filters currently existing.

 In order to facilitate the introduction of the catheter and the filter into the veins, in a known manner, the catheter has a flexible guide 27 along which the catheter is capable of sliding and whose distal end 28 is curved.

 The guide 27 runs through the duct 15 and opens out inside the cylinder defined by the branches 2 folded, for example at the orifice 24.

 FIGS. 4 to 6 schematize the different phases of implantation of the filter in the inferior vena cava 29 of a patient, or the direction of flow of the blood flow has been schematized in 30.

 In a first phase, in a known manner, the guide 27 was introduced percutaneously using the jugular vein or the femoral vein, until its end 28 is substantially in position in the inferior vena cava of the patient.

 Then, by an action from outside the patient's body, the catheter slid along the guide 27 until its distal end 17 comes into position in the inferior vena cava.

 Until this positioning, the filter 1 is in the folded state inside the distal end 17 of the sheath 16 which also surrounds the zone 6 of the duct 15.

 In the next phase shown diagrammatically in FIG. 5, by an action from the outside, the sheath 16 slides relative to the duct 15 so as to bring the filter 1 out of its distal end 17.

 It should be noted that the filter remains in the folded state and that the branches are closed on axis 5.

 At this stage, possibly, the sheath 16 is removed by sliding it along the conduit 15 inside the patient's body and opening it along its slot on the outside.

 Likewise, the guide 27 is possibly removed.

 In the next phase from the outside, a substance is injected into the balloon 8 so as to cause it to swell and the branches 2 of the filter 1 to deploy.

 As can be seen in FIG. 6, the amplitude of the deployment of the branches 2 of the filter 1 is sufficient for at least their distal zone 10, that is to say approximately one third of their length, to be applied against the internal wall of the vein 29 and deforms in contact with this wall.

 It is this area of the branches bearing against the wall of the vein 29 which not only ensures the maintenance of the filter but also its centering.

 It should be emphasized that the flexibility of the branches, and the possibility of adjusting the inflation of the balloon 8 make it possible to adapt the filter 1 to different diameters of vein, in particular to adapt it to megacaves, whose diameter exceeds twenty eight millimeters, this it also allows him to follow the distensions of the vein over time while remaining centered in the vein.

 As previously described, when the filter is in position, it is possible to inject fibrinolytic substances and a heparin serum into the blood.

 In the case where the filter is temporarily installed, passes the intervention period, the filter removal operations are carried out in reverse order, namely the deflation of the balloon to fold the branches back on themselves and then the removal of the entire catheter from the patient's vein.

 Good results have been obtained using a filter 1 consisting of eight flexible arms 0.30 millimeters in diameter, made of hemocompatible material, for example known under the name of "HEPARIN-LIKE", with a length of approximately 6 centimeters, 1.5 cm of which is used for assembling the arms on the distal end of the catheter.

 The arms 2 are separated by the inflation of a balloon 8 also made of hemocompatible material, the volume of which can vary between 0.25 and 1.50 cm / cube approximately.

 The product used for inflating the balloon 8 is either a serum or a radiopaque liquid.

 The inflation of the balloon is determined so that the distal area of the branches 2 of the filter 1 is applied over approximately two centimeters on the internal wall of the inferior vena cava 29.

 The branches 2 of the filter 1 are connected together by a hemocompatible filament 12, which is threaded inside the orifices of the branches, and which constitutes a mesh over a length of about #four centimeters of the branches.

 The filament 12 describes a spiral, and the difference between two successive revolutions, measured on a branch 2, is variable and it decreases from the balloon 8 from five millimeters to about two millimeters.

 Referring to the French scale of catheters commonly used, the # fllter catheter is of size 8F, that is to say approximately 2.66 millimeters in diameter, it is mounted in an external sheath of introduction 16 of size 9F whose length is about one hundred and ten centimeters and the materials used are also hemo-compatible.

 It goes without saying that the figures are given for information only and have no limiting value for the invention.

 The filter according to the invention and its filter-carrying catheter therefore allow a partial and temporary obturation of the inferior vena cava in a human being.

 The filter also allows partial and temporary filling of another vein in the same way.

 It has the main advantage of having a temporary action that is to say mainly preventive.

 However, the filter according to the invention can also be implanted definitively inside a vein and in particular of the inferior vena cava.

 Naturally, the present description is given for information only and other implementations of the invention could be adopted without departing from the scope thereof.

 In particular, other means could be added to the catheter enabling it to fulfill known functions, for example endoscopy.

Claims (10)

 1. Filter for partial and at least temporary interruption of a vein, in particular the inferior vena cava of a human being, for the purpose of retaining clots and preventing a pulmonary embolism or a recurrence, comprising a plurality of flexible arms (2), joined together at their proximal end (3) extending at rest approximately parallel to one another along the generatrix of a cylinder, up to their distal end (4) CHARACTERIZED by the fact that it comprises deformable means for reversible expansion of the branches (2), remotely controllable, which are located inside the cylinder defined by the branches (2) at rest and which, by deformation, exert on the branches (2) a thrust from the inside so as to deploy them in the manner of the branches of an umbrella, of sufficient amplitude for each branch (2) to be applied at least in its distal zone (10) against the wall of the vein (29 ).  2. Filter according to claim 1, characterized in that the means for expanding the branches (2) comprise an expandable balloon (8), which can be inflated at an adjustable distance, which is located inside the cylinder defined by the branches (2) and which, by deformation, expands at least radially and exerts a thrust on them and deploys them in the manner of the branches of an umbrella.  3. Filter according to claim 2 characterized in that the balloon (8) is traversed longitudinally right through by the end (6) of a conduit (15) on which it is fitted in a sealed manner and that the conduit (15) connects the interior of the balloon to external inflation means.  4. Filter according to any one of claims 1 to 3 characterized in that these branches (2) are, at least in their proximal area (11), connected by at least one flexible filament (12), so as to constitute a mesh.  5. Filter according to claim 4 characterized in that the flexible filament (12) is unique, that it is threaded in orifices distributed over the proximal zone 11 of the branches and that it connects the branches successively one after the 'other by substantially describing a spiral which closes radially towards the balloon (8).  6. catheter carrying the filter according to any one of claims 1 to 5 for the partial or at least temporary interruption of a vein in particular of the inferior vena cava of a human being, of sufficient length so that its end distal (13) that extends the filter (1) is at the level of the vein to be partially closed and that its proximal end (14) is outside the patient's body, the catheter comprising a longilinear conduit (15) capable of sliding longitudinally a the inside of an external insertion sheath (16) in the distal end (17) from which the filter (1) can be housed in the folded state, CHARACTERIZED by the fact that it comprises reversible means for controlling from its proximal end (14) the deployment of the branches (2) of the filter (1) and for adjusting the amplitude of said deployment.  7. Catheter according to claim 6 characterized in that it further comprises means for infusing into the blood, in the vicinity of the filter (1), a liquid substance from its proximal end (14).  8. Catheter according to claim 2 or 6 characterized in that the means comprise a pipe (20) traversing the conduit (15) opening at its distal end inside the balloon (8) and having at its proximal end means (22) for injecting a defined volume of fluid into the balloon and for aspirating said volume.  9. Catheter according to claim 7 characterized in that the said means comprise an infusion pipe (23) traversing the said conduit (15) opening at its distal end by an orifice (24) located inside the branches (2) and by at least one orifice (25) situated behind the filter and having, on the side of its proximal end, means (26) for connecting it to infusion means.  10. Catheter according to claim 6 characterized in that it further has an introduction guide (27) along which it is capable of sliding.