FR2625437A1 - Anti-embolism elastic filtering system for vena cava - Google Patents

Abstract

The invention relates to a system for combatting coagulated blood embolisms moving towards the pulmonary arteries. It is fitted percutaneously through a catheter 7 F and does not require general anaesthesia. The assembly consists of a final flexible filter, a catheter 7 F, a pusher, a Y connecter for lateral injections, an extractor and a positioner.

Description

The invention that we propose is a cellar filter system against cruole embolism. It has for ssion this st # - per the migration of tnromsus coming from the venous circulation ~ s- peripnéric of the leading members or the small pelvis and being directed towards the pulmonary arteries; place where they could cause obstruction of large kranc; nes, severe embolism often fatal.

Other filter systems which partially interrupt the flow of the inferior vena cava already exist
- the oldest is represented by the intraabdominal technique of interrupting the flow of the inferior vena cava (IVC) by ligature or surgical plication. Variants of this technique were brought by the use and the installation of external clips coming in clamp partially interrupting the VCI The oldest is the clips of ADAMS DE WESE which reduces the caliber of the VCI by dividing it into several small channels . This clamp system is placed on the external wall of the IVC after laparotomy under general anesthesia.

The mortality rate from these surgical techniques has been estimated at 12%. Peripheral venous stasis is present in more than 30% of cases.

 - Then come the endovenous filters. They require the surgical approach of the internal jugular vein under general anesthesia or local anesthesia. The oldest is the MOBIN-UDIN filter. The size of its placement sheath is large and sometimes represents a limit to its use on narrow or tortuous jugular veins. Through frequent thrombosis, it can cause lower venous stasis syndrome.

 - The EREENFIELD filter has the same disadvantages of placement by the internal jugular vein due to the size of its sheath. It can also be placed from the femoral vein, but always requires surgical or percutaneous stripping. The multiplication of radial anchor points appears traumatic for the wall of the V.C.I.

 - A fourth endovenous filter called the CUNTHER filter also requires a high caliber introducer through the 10 F percutaneous route.

 - The DOM medical filter has the same size as the Greenfield filter which requires a 10 F introducer; its implementation is surgical or percutaneous. The multiplication of radial anchor points appears traumatic for the V.C.I.

 - Finally, another percutaneous deformable filter has been proposed against peripheral venous embolism towards pulmonary cirlation, but it has never been used in human clinic.

 The invention that we propose makes it possible to avoid the significant morbidity of the other endovenous filters mentioned above.

The present invention therefore consists of a flexible endovenous filter and its percutaneous system 7 F for placement. The flexible filter installed in the V.C.I. causes a deformation of it in a plane, without stopping its flow. The flattening thus obtained, as well as the various arches of the filter intersecting the flow, stop the migration of large sanitary clots from the peripheral venous network.

The present invention will be described below with reference to the accompanying drawings (Figs. 1 to 12) with the objectives
- Use the percutaneous route for its placement using a catheter system whose external diameter does not exceed 7 F.

 - The small diameter of the catheter allows the venous approach of its choice: jugular vein, femoral vein, but also cephalic or humeral vein of the upper limb which represent the routes of choice for carrying out pulmonary angiographies.

 - By the same catheter, before the placement of the filter, our invention allows angiographic exploration of V.C.I.

and if necessary, pulmonary angiography.

 - The small diameter of the catheter and its flexibility allow under luminance amplifier, to cross, without aggression the venous wall, sinuosities of the veins of the upper limb then to reach and cross the right atrium to position itself exactly at the place desired, in the inferior vena cava.

 - Yn other ~ oh e ~ z-, of our intention esz this to drop the other because ur sense or ans the other; uln according to the belief: of the venous venous approach.

 - One of these purposes of this of OC is to modify the diameter of the V.C.I. on an author's fault not exceeding three to four centimeters. This further reducing the risk of malposition of the filter in a collateral vein.

 - One quality of this filter is that it does not damage the venous wall. Only, its proximal end by its sharp point, is plugged into the venous wall. The rest of the filter resuming its elastic effect and its shape in a single plane, without attacking the endothelium.

 - Another advantage of this filter is its method of fixing in the V.C.I. Indeed, after a few days, endothelialization occurs. The outermost loops are thus fixed in the venous wall, giving the filter final stability and preventing any risk of my ntion to the heart and pulmonary arteries.

 - One quality of this deformable filter is its ease of installation. The height drop chosen in the V.C.I. by pressing the pusher through the catheter containing the filter. The catheter itself must remain fixed.

 The push guide is also radio-opaque.

 - The original quality of this deformable filter system is its high "elastic" power; the single direction of rotation of the ellipses in the same plane allows instantaneous resumption of its initial shape after release into the V.C.I.

Unrolled in the carrying catheter, it remains flexible and allows easier handling. Once released, the radiopaque filter by modifying the diameter of the V.C.I. by its elastic effect on the walls, does not interrupt the venous flow but allows, by the deformation of the V.C.I., the arrest of blood clots, the filter itself not being thrombogenic.

 - Another quality of this filter system and its percutaneous delivery system is the possibility at any time to control by injections of radioopaque products, the correct position of the carrying catheter; also the emptiness of the V.C.I. at the height chosen for the release of the filter. This manipulation can be done when the catheter already contains the deformable filter.

 In fact, the distal end of the catheter 7 F is connected by screwing onto a connector with lateral injection path (plate 5/5). The pusher guide must in this case be pulled back (fig31 plate 5/5) so as to occlude the distal end of the connector, thus making the system watertight, during injections by the lateral path of the Y system.

 - An objective of this invention is the possibility of being able to first mount in the carrying catheter a teflon-coated guide in J, in the event of difficulty in raising the probe by a sinuous peripheral vein. The carrying catheter, once in place, the filter is pushed through it and released.

The qualities of this invention are
1. Its effectiveness against massive pulmonary embolism;
the establishment being final.

2. Its harmlessness for the IVC wall; his absence
local thrombogenic effect.

3. 3. Its very low morbidity linked to the use of a
small 7 F percutaneous catheter
4. The simple use of local anesthesia.

 The present invention therefore consists in putting in place as a filter, a metal wire with a spring effect, the final geometry of which was produced during its own manufacture (plate 1/5). This elastic filtering system is made of cobalt-chromium wire with a diameter of 0.3mm, the length is variable depending on the sizes considered.

One end, that is to say, that which comes first into contact with the vein, is terminated by a sharp point, (plate II / 5) followed by a loop whose outside diameter D is less than that of a 7 F catheter. This loop has two functions
- firstly, avoid the filter crossing the vein, therefore playing a role of stop.

 - secondly, allow the introduction of the filter into the catheter as well as its positioning in the desired location, this thanks to a traction element independent of the system.

In the profile plane, this end is offset outwards by 8 to 10 mm at an angle of 450 (I / V plate).

The purpose of this shift is to easily "tan" the end in the vein and subsequently allow the first loop to rotate around this anchor point.

 Still in the plane of the profile, the end therefore joins the first loop and the elastic filtering system has the appearance of 2 ellipses whose axes of the hearths form an angle of 900 between them. This configuration puts the system in permanent tension balance and the spring effect rarely plays on the 4 contact points at the same time.

 This permanent tension applied to the walls of the vein causes the flattening thereof, passing it # from a round section to an eiptic section to become a round section above the system.

 The last end remains in the same plane, the wire is folded back on itself by 4mm so as to increase the contact surface with the pusher when the system is released into the vein.

 - Installation of the elastic filtering system in the carrying ca theter (Plate III / V -fig.5-b-7), by its proximal end.

- Hang the 1.2mm diameter ring located at the end of the filter (plate III / V - fig. 5) in the open loop of the introducer cable, then push the flexible sheath already in place on the introducer cable until it comes to a stop on the filter ring. (board HERE / 5 - figb
- The purpose of this protective sheath is to allow perfect sliding of the end of the filter in the catheter.

 - make sure that the final end of the filter, that is to say the part located after the ring of length 2 to 3 mm which is perfectly sharp, is well tucked inside the fear.

 - These precautions being observed (board HERE / 5 - fig. 7), pull the other end of the cable until the sheath appears towards the outside (board 4 / 5- fig. 8) and unhook the introducer cable ( plate 4/5 - fig. 9).

 - If necessary push the filter a few millimeters (plate 4/5 - fig. 10) towards the inside of the catheter so that no part of the filter protrudes from the end of the catheter, using a tool special supplied in the kit.

 - This process completed, the elastic filter / catheter assembly is ready to be introduced into the mesh already in place.

 As described above, control of the correct position of the carrying catheter is made possible by injections of radiopaque product thanks to the lateral injection connection (plate 5/5).

Claims (9)

1) Anti embolic filter system for veinecave, characterized  by the fact that it is made from a metallic wire to  spring effect whose final geometry has 2 ellipses  the main axes of which form an angle between them  90 ~, effectively giving 4 permanent points of contact with the  vein where it is set up. 2) elastic filter system according to claim 1, character  laughed at by the fact that one of its ends is terminated by a  accelerated point preceded by a loop whose diameter is in  smaller than the inside diameter of a catheter used for its  placement, this accelerated point being the only point of year  creation in the V.C.I. 3) elastic filter system according to claims 1 and 2  characterized by the fact that the second end of the system  offers a larger contact surface than the cross section of the wire. 4) Elastic filtering system according to any one of the claims  cations 1 to 3, characterized in that it is produced in  cobalt-chromium alloy with a balance of around 40%.  male accessed from the filter into the catheter.  - 1 fork tool to position the proxi end  inside the delivery catheter  - 1 traction system to install the derou filter  Y and inside caliber of catheter 7 F  - 1 pusher guide specially adapted for the connection in  - I guide in Teflon-coated J  lateral  by screwing on a Y-connector with injection track  lumen and a distal end connecting  - 1 positioning catheter 7 F, radiopaque at one  by the fact that it is composed of  according to any one of claims 1 to 4, characterized  5) Set of means for setting up the filter system 6) An assembly according to claim 5, characterized in that  the push system is made of braided stainless steel wire  0.7mm outer diameter and one end of which is finished  by a conical tip.  pusher.  rear intended to come into contact with the conical part of the  in Y whose distal end is provided with a special plug  lateral injection system consists of a connector  7) An assembly according to claim 5, characterized in that the  8) assembly according to claim 5, characterized in that  the traction system consists of a stainless steel wire  0.5mm diameter dolly with one end terminated  born by an open hook and a sheath of 20mm length  whose outside diameter is less than the inside diameter  7 F catheter 9) assembly according to claim 5, characterized in that  that the tool for positioning the filter is cylindrical in shape  than a diameter smaller than that of the catheter and one of which  ends is finished in "fork".