CA2047280A1 - Apparatus for temporary implantation of a blood filter in a human vein - Google Patents

Abstract

This device comprises an elastic guide wire, onto which a semi-rigid tubular mandrel can be fitted, itself fitted into a thin-walled tubular sheath; there is provided a catheter in the form of a flexible tube which is easily divisible, the distal end of which permanently carries the blood filter, and the proximal end of which is intended to receive a locating organ which will be trapped under the skin of the patient after temporary implantation of the filtered; a removable stiffening cable can be removably inserted into the catheter to move the filter along the sheath during its placement in a vein, in particular in the inferior vena cava of a patient. This filter can be easily removed after a certain period, when the risks of pulmonary embolism are no longer to be feared.

Description

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DlSPOSlTlF TEMPORARY IMPLEMENTATION OF A BLOOD FILTER ~
IN A VEIN OF THE HUMAN BODY

The present invention relates to a device temporary implantation, in a vein of the human body, and particular in the inferior vena cava of a patient, a blood filter, and more particularly a blood filter elastically expandable type in radial direction.
The function of blood filters is to retain blood clots that can form during phlebitis or other cardiovascular or vascular diseases, in order to prevent their migration to the pulmonary arteries where they would risk cause embolism.
The filters generally used for this purpose have the general shape of a small umbrella formed of a plurality of flexible arms, radially expandable. In rest position (retracted state), the branches extend approximately parallel-together and occupy a reduced dimension in radial direction, which allows their placement in a vein. Once in place inside the vein, the branches automatically deploy outward to lock against the wall of the vein, anchoring the filter to the desired location.
Such filters are preferably installed in the inferior vena cava, slightly below the level of the kidneys.
Traditionally, the apparatus which allows set up the filter includes a guide rod and a mandrel which allow a sheath to be inserted into the vein desired depth, so that the end of the sheath arrives at the place where the filter should be placed. When the filter is set up in the inferior vena cava it is known to operate the implantation by a percutaneous access route or by ~ D3 ~ 2 ~

"denudation" at the level of the right internal jugular vein. The placement is therefore done from the jugular vein, via the superior vena cava. After fitting the sheath, the mandrel and the guide rod are removed; the filter is then intro-dispenses into the sheath using a special syringe, and is moved inside the sheath, all along the sheath, at using the mandrel, the latter then playing the role of a pusher.
When the filter reaches the free end of the sheath (preliminary-positioned at the desired location of the inferior vena cava) it deploys automatically and is anchored in the wall of the vein. The sheath is then removed and the filter therefore remains in place permanently.
The main disadvantage of this technique is that it the filter cannot be removed unless very delicate surgical operation. Unfortunately7 the maintenance final filter in the vena cava is a source of complica-tions, particularly as a result of the thromboses it can trigger;
moreover, the wearing by the patient of the filter requires that he has for life a anticoagulant medication.
ZO These disadvantages are all the more regrettable since, in many therapies, keeping the filter in the vein is only necessary for a limited period, usually from a few weeks or a few months, corresponding to a period during which the risk of embolism is real.
This is why a technique has recently been proposed.
temporary implantation of the filter, which can be removed after a certain amount of time.
For this, the mandrel which is used to install the filter is permanently united to the latter; after implantation of the filter, the mandrel remains inserted in the vein and comes out of the body by the access route used for implantation, that is to say at level of the neck, in the region of the jugular vein, for a J; ) ~ '.J (~ ~ 3 implantation of the vena cava. Unfortunately, wearing a such rod, which is relatively rigid, is very uncomfortable for the patient; moreover, because the mandrel comes out of the skin, it constitutes a source of infections liable to cause S risk of serious complications, including septicemia.
This is why, the object of the present invention is to remedy these drawbacks by proposing a new device implantation of a blood filter of the kind mentioned above, this device being simple to handle and use, this so reversible, without the patient having to run any real risks of infections or is traumatized by the presence of the device implanted during the entire period in which it must keep the filter.
Throughout the description and claims, the terms "proximal" and "distal" are used by taking as reference the location of the patient's body through which the filter blood is introduced. According to this definition, the pro ~ i- end male of an element is the one closest to the place introduction and the distal end is the most distant.
The device which is the subject of the invention is characterized in that that it is composed of the following elements:
a) an elastic guide wire of small diameter intended to be inserted into the vein through a percussion access tanned or after denudation;
b) a semi-rigid tubular mandrel capable of being fitted on the guide wire and moved the lonq thereof;
c) a thin-walled tubular sheath which can be fitted chée on the mandrel and placement inside the vein by following the displacement of the mandrel along the guide wire;
d) a catheter in the form of a flexible tube which is easily seca-ble, the distal end of which permanently carries the blood filter;

e) a stiffening cable which can be inserted in any way removable in the catheter, allowing movement inside of said sheath previously placed the catheter and its filter the retracted state, until the latter comes out at the end distal of the sheath and then deploys automatically to anchor against the wall of the vein;
f) a locating member intended to be fixed to the outside proximal catheter mite after removal of said stiffening cable cator and sectioning of the catheter at the access route.
By the way, according to a number of characteristics advantageous, but not limiting:
- the proximal ends of said mandrel and said sheath each carry a female sleeve-shaped head with LUER international standards, the head carried by the mandrel being adapted to come into abutment against the head carried by the sheath, to facilitate their joint installation inside the - vein;
- the device comprises a tubular syringe body able to be fitted onto said catheter and to receive the filter to maintain it in the retracted state;
- the proximal end of the head carried by the sheath and the distal end of the syringe body are provided with means additional couplings meeting the standards known as "LUER-Lock "such as threading / tapping facilitating the introduction of filter in the previously installed duct;
- Said locating member has the shape of a sleeve ready to be crimped onto the catheter;
- said locating member is a sleeve without sharp angles, for example of ovoid shape;
- said locating member is made of plastic material that overmolded on a metal ring;
- said catheter is made of plastic, by example in polyvinyl chloride covered with a biocom material patible such as a silicone-based material;

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- the distal end of said mandrel carries a mark radiopaque, for example a metal ring;
- the distal end of the catheter, which carries the filter, is closed.
Other features and advantages of the invention will appear; will be from the description and attached drawings which present a preferred embodiment.
In these drawings:
- Figure 1 shows the different elements guardians of the device;
- Figure 2 shows in longitudinal section the distal mite of the catheter fitted with the blood filter;
- Figure 3 is a schematic view illustrating the setting in place of the filter in a patient's inferior vena cava;
- Figure 4 is a longitudinal sectional view of the marker body;
- Figure 5 is a schematic view of the catheter, the proximal and distal ends are provided respectively of the locating member and the filter.
The various main constituent elements of the provision sitive, shown in the drawings, have been referenced from the as follows: guide wire 1, tubular sheath 2, mandrel tubular 3, catheter 4, filter 5, stiffening cable 40, organ 7 and syringe body 6.
Wire 1 is a wire of small diameter, for example metallic, which is elastically flexible, but has everything even a certain rigidity. Its distal end 10 is curved to form a half loop, which gives the thread the general look of the letter J.
3 ~ The sheath 2 is a thin-walled cylindrical tube produced made of plastic, for example polyvinyl chloride. She is open at both ends. At its proximal end, it ~ Q 15 7; '3- ~

carries a head 20 in the form of a sleeve, also made of plastic tick, whose diameter is larger than the outside diameter laughing sheath. This sheath has a certain flexibility.
On the free end (proximal side) of the head 20, there is provided a step of YiS 200 made up of one or more nets (standards LUER-Lock).
The tubular mandrel 3 consists of a rod made of material semi-rigid plastic, the internal diameter of which corresponds to diameter of the wire 1, which allows its fitting on this wire, while its outer diameter corresponds to the inner diameter ~ laughing of the sheath 2, which allows the sheath to be fitted onto the mandrel.
The mandrel shanks on the wire and the sheath on the chuck are sockets provided with sufficient play to allow the relative longitudinal sliding of these three lS elements.
The tubular mandrel 3 carries at its proximal end a head 30 in the form of a sleeve in accordance with LUER standards; this last has an extension 33, cylindrical or slightly conical, adapted to come to nest in a complementary housing provided in the sheath head 20; after fitting, the sheath 2 and the mandrel 3 are therefore perfectly integral with each other if although by handling only one of the two heads 20 or 30, it it is possible to move the mandrel and sleeve assembly. The end distal 32 of the mandrel has a conical shape with a rounded apex, this gentle shape avoiding aggression during implantation tion of the device.
A short distance from the end 32, it is provided on the mandrel 3 a radiopaque marker 31, for example constituted by a small metal ring. The relative lengths of the sheath and the mandrel are determined so that after fully depressing the mandrel in the sheath (head 3û in abutment against head 20) the mark 31 comes out just at the distal end of the sheath.

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The catheter 4 consists of a very flexible tube (not rigid) whose outside diameter is significantly smaller than that of the sheath 2.
~ e catheter 4 is made of a plastic material covered with a bio-compatible material such as a base material silicone; the plastic is for example chloride of polyvinyl. Advantageously, the mandrel is made radiopaque, for example by inclusion of barium sulfate particles in the material that constitutes it.
As already said, the catheter 4 has a tubular shape, and it can receive in its central light a stiffening cable 40 of corresponding diameter, this cable being for example constituted by a very thin spring steel wire wound on itself heli-coidally over its entire length.
As seen more particularly in Figure Z, the distal end of the catheter 4 is closed by an element 52 which forms part of the filter 5. The sliding of the stiffening cable 40 in catheter 4 (sliding represented by the double arrow f in Figure 2) is therefore limited in the distal direction, so that the cable serves as a pusher when the catheter is introduced, as will be explained later.
The filter 5 is a filter of the type known per se, of the kind described in the preamble to this description. In the mode shown, the filter has the shape of a frame umbrella which has eight branches formed by fine flexible metal strips. Four branches are planned long 50 alternated with four shorter branches 51, according to a regular angular distribution at 45.
These branches are embedded at their proximal end in the closure cap 52 of the catheter 4. Their end distal is slightly curved so as to present a direction tion substantially parallel to the longitudinal axis XX ′ of the filter and ~. .

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catheter. It is thus understood, when the filter is at the deployed state ~ state shown in the figures) the ends free of branches 50 and 51 come to be properly plated against the wall of the vein without risk of attacking it.
The device also includes a syringe body in plastic material 6, which has the form of a tubular sleeve sliding on the catheter 4. The length of the body 6 is a not much greater than the length of the branches of the filter 5. Sound internal diameter corresponds approximately to the internal diameter sheath head 20 and sheath 2.
The distal end of the body 6 is tapped so as to present a thread 60 complementary to the thread 200 of the head sheath 20 according to LUER standards.
The locating member 7, shown in Figures 4 and S
includes a body 70 in the form of a small sleeve made of material flexible plastic. This sleeve, devoid of sharp angles, has the form general of a small olive whose central part more swollen is molded onto a metal ring 72.
As shown in Figure 4 by arrows 9, the crimping of the locating member 7 on a rod beforehand fitted into the central hole 71 of the body 70, and consequently the attachment of the member 7 on this rod, can be easily obtained by crushing the central area of the sleeve and deforming tion of the ring 72. As will be seen below, it is thus possible to simply attach the member 7 to the proximal end catheter male 4.
We will now explain how the device which has just been described is used for setting place of a blood filter in the lower vena cava of a body reversible, the filter can be easily removed later.

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The implantation of the filter is done under local anesthesia of the patient, which is referenced H in FIG. 3. Classically sic, the operator begins by creating a path in the neck percutaneous access VA of the right internal jugular vein VJ, or by stripping.
In a first phase, it introduces into the vein jugu-laire the guide wire 1. Under radiological observation, rendered possible by radio-opacity of the wire, it lowers the latter in the jugular vein then makes him borrow the vena cava superior VCS and then the inferior vena cava VCI. Because that the distal end of the guide rod is bent, this extremity does not constitute a cause of snagging or trauma tism during its displacement. This operation stops when the end 10 came a little beyond the area where the filter must be installed, below the irrigation bifurcations kidney.
He then makes a small incision to widen on either side of the guide entry point to facilitate the opera-next tion.
In a second phase, the head 30 being in abutment against head 20, the operator sits on the proximal end of the wire 1 (which of course emerges from the jugular vein) shutter formed by the mandrel 3 and the sheath 2; he brings down gently this assembly along the wire 1, until the mark radiopaque 31 reaches the zone provided for anchoring the filter.
In a third phase, he removes the wire from the sheath 2 1 and the mandrel 3.
In a fourth phase, while the syringe body 6 covers the filter 5, which is therefore in the state folded back, it couples this syringe body to the head 20 of the sheath using complementary screwing means 60, 200.

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lo In a fifth phase, the stiffening cable 40 is finding inside the catheter 4, it lowers this set ble so that the filter 5, still in the retracted state, is transferred first to head 20 then to sheath 2. ^ -The thrust force which is applied by the operator to the extremi-~ distal of the catheter assembly 4 - cable 40 is transmitted corrected;
due to the stiffening role of the cable, if although the filter descends gradually along the duct 2.
This would be difficult in the absence of cable 40 due to the flexibility of the catheter (which is semi-rigid).
When the filter has reached the distal end of the sheath 2, it deploys automatically due to the flexibility branches 50, 51, which are applied against the walls of the vena cava in the desired location, which achieves anchoring the filter.
In a sixth phase, the operator removes the sheath 2 from the vein.
In a seventh phase, he removes the cable from the catheter 4 40, then cuts the catheter outside the jugular vein laire, a short distance from it. This sectioning can be conveniently carried out due to the easily breakable nature of the catheter, for example using a pair of surgical scissors ordinary.
~ in an eighth phase, the operator goes to the protruding proximal end of the catheter the locator 7, then fixed by crimping using an appropriate tool, by example pliers.
Finally, the operator makes the small incision lies a cubicle under the skin muscle of the neck, where it buries organ 7. Then it closes the access path VA so conventional, so that the member 7 remains trapped under the skin after suturing. There is therefore no risk of infection by transcutaneous route at the neck.

'2 3 a It should also be noted that the fact that the catheter 4 is closed at its distal end, any risk of blood reflux into the catheter in the direction of the access route is avoided; in addition, the crushing of the locating member 7 on the catheter causes also the obturation of the latter at its proximal end.
Due to its flexibility, the catheter does not interfere in any way neither the patient nor disrupts their activities; he is completely "forgotten" by the patient during the entire phase when the filter must be kept in place in the inferior vena cava. The duration of keeping the catheter and filter can be increased by a few weeks to months thanks to the invention, when it is not only two to three weeks in temporary installation techniques rary implemented so far, with the risks of infection related to this technique.
You can check the position at any time organ 7, either by palpating the patient's skin, or under radio spelling. When the filter needs to be removed, just open it to the VA access channel again, and remove the filter from the vein by pulling on the end of the catheter 4. The particular shape filter, which can contract freely towards the interior laughing, authorizes its movement along the VCI, VCS and VJ veins.
The main principles will be given below, for information only.
possible dimensions of the device.
The mandrel 3 and the sheath 2 may have a length of order 50 to 6 ~ cm, the catheter 4 a length of the order of 60 to 80 cm, wire 1 and cable 40 lengths of the order of 80 to ~ 00 cm.
The guide wire 1 and the stiffening cable 40 for-ront have a diameter of the order of 0.5 to 0.7 mm; the chuck 3 3 ~ and the sheath 2 may have respectively outside diameters laughers of the order of 3.5 and 4.2 mm, while the catheter 4 ``

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may have an outside diameter of the order of 2 mm. The branches long ches 50 of filter 5 could have a length of the order 40 mm, while its short arms 51 may have a length of the order of 25 mm.
After fitting the device, the effective length of the catheter ter, i.e. the length between filter 5 and the locating member 7 will generally be between 40 and 55 cm.
All the constituent elements of the object device of the invention are intended to be packaged in the same sterile, single-use packaging for marketing tion and their delivery to medical and surgical centers.

Claims (10)

1. Temporary implantation device, in a vein of the human body, and in particular in the inferior vena cava (VCI) of a blood filter (5) of the elastically expandable type in radial direction, characterized in that it is composed of following items:
a) an elastic guide wire of small diameter (1) intended to be inserted into the vein through a percussion access tanned (VA) or by stripping;
b) a semi-rigid tubular mandrel (3) capable of being fitted on the guide wire (1) and moved along it;
c) a thin-walled tubular sheath (2) which can be fitted onto the mandrel (3) and placed inside the vein (VCI) due to displacement of the mandrel (3) along the wire guide (1);
d) an easily flexible tube-shaped catheter (4) breakable, the distal end of which permanently carries the filter blood (5);
e) a stiffening cable (40) which can be inserted from removably in the catheter (4), which allows movement to the interior of said sheath (2) previously placed the catheter (4) and its filter (5) in the retracted state, until the latter comes out at the distal end of the sheath and then deploys automatically to anchor against the wall of the vein (VCI);
f) a locating member (7) intended to be fixed to the proximal end of the catheter (4) after removal of said cable stiffener and sectioning of the catheter at the level of the channel access (VA). 2. Device according to claim 1, characterized in that that the proximal ends of said mandrel (3) and said sheath (2) each carry a sleeve-shaped head (30, 20), the head (30) carried by the mandrel (3) being adapted to come into abutment against the head (20) carried by the sheath, to facilitate their placing in joint place inside the vein. 3. Device according to one of claims 1 to 2, characterized in that it comprises a tubular syringe body (6) able to be fitted onto said catheter (4) and to receive the blood filter (5) to keep it in the retracted state. 4. Device according to claims 2 and 3 taken combination, characterized in that the proximal end of the head (20) carried by the sheath (2) and the distal end of the body syringe (6) are provided with complementary coupling means shutters such as thread (200) / internal thread (60) facilitating intro-duction of the filter (5) in the sheath (2) previously installed. 5. Device according to one of claims 1 to 4, charac-terized in that said locating member (7) has the form of a sleeve intended to be crimped onto the catheter (4). 6. Device according to one of claims 1 to 5, characterized in that said locating member (7) is a sleeve devoid of sharp angles, for example of ovoid shape. 7. Device according to one of claims 1 to 6, characterized in that said locating member is made in plastic material overmolded on a metal ring. 8. Device according to one of claims 1 to 7, characterized in that said catheter (4) is made of material plastic, for example polyvinyl chloride covered with a biocompatible material such as a silicone-based material. 9. Device according to one of claims 1 to 8, characterized in that the distal end of said mandrel (3) carries a radiopaque marker, for example a metal ring (31). 10. Device according to one of claims 1 to 9, characterized in that the distal end (41) of the catheter (4), which carries the filter (5), is closed.