WO2011010296A1 - A device for treating valvular malformations in peripheral venous vessels, such as internal jugular veins and kit therefor - Google Patents

Abstract

A device for venous valvulotomy, usable for example for valvulotomy of the jugular veins includes: - a cutting tool (12) having at least one cutting formation (120) for performing the action of valvulotomy; and - a collection element (14), set in a proximal position with respect to the cutting tool (12) for collecting the residue of valvulotomy entrained by the blood flow from the cutting tool (12).

Description

"A Device for treating valvular malformations in peripheral venous vessels, such as internal jugular veins and kit therefor"

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TEXT OF THE DESCRIPTION

Field of the invention

The present disclosure relates to devices for the treatment of peripheral vessels.

The present disclosure has been developed with particular attention paid to its possible use in the treatment of the jugular veins.

Description of the known art

Documents such related as PCT/IB2008/000621 and PCT/IB2008/000623 and again TO2008A000654 have highlighted the existence of a possible correlation between chronic cerebro-spinal venous insufficiency (CCSVI), in particular at the level of the internal jugular veins (IJVs), and the onset of multiple sclerosis (MS) .

Said preceding documents describe various techniques for detecting the risk of onset and/or treating said clinical picture.

Objects and summary of the present invention

The object of the present invention is to provide further improvements with respect to said techniques.

According to the present invention, said object is achieved thanks to a device having the characteristics recalled in the ensuing claims. The invention also relates to a respective kit comprising, together with the device described herein, also instruction means (e.g., printed instructions) for the use of said device for a valvulotomy in a venous context, such as for example the proximal segment of the internal jugular vein .

The claims form an integral part of the technical teaching provided herein in relation to the invention.

The solution described herein stems from the fact, noted by the inventor via ultrasound, venographic, histological, and post-mortem investigations, that an important percentage of patients affected by chronic cerebro-spinal venous insufficiency associated to multiple sclerosis have in the proximal segment of the internal jugular vein (or IJV) a malformed valve roughly corresponding to the morphologies represented in Figures 1 and 2.

Both Figure 1 and Figure 2 are schematic representations of the proximal stretch of the internal jugular vein IJV in which there may be found the presence of a malformed valve V that may present either as a "normal" valve the valve leaflets L of which are oriented in a direction opposite to the direction of circulation of the blood (represented by the arrow BF and hence oriented downwards so as to indicate a direction of blood flow from the brain to the thorax - note that it is a venous vessel) or as a valve the nonfunctioning cusps C of which act in effect as diaphragm. In either case, this leads to an incorrect closing of the valve at the moment of inspiration, with a net effect of regurgitation of the blood towards the brain. Said effect lies at the basis of onset of the picture of chronic cerebrospinal venous insufficiency.

Other morphological variants of this valve malformation may be noted, amongst which the most frequent are those of valve cusps oriented in a transverse direction, or else fixed valve cusps that are unable to open or closing, respectively, for favouring the blood flow or for preventing reflux thereof. Whatever the morphology, the malformation of the valve prevents proper passage of the blood from the brain to the right atrium, thus configuring a picture of CCSVI.

A treatment of percutaneous transluminal angioplasty (PTA) usually proves ineffective in remedying in a durable way a situation of this nature: the experimental data indicate in fact that a treatment of PTA gives rise to recurrence of the pathological condition in a very short period of time.

In one embodiment, the solution described herein treats the condition outlined previously via endovascular valvulotomy (hence of a non-invasive or minimally invasive type) of the malformed valve.

Endovascular valvulotomy has so far been limited to interventions in arterial contexts (for example, for performing ablation of the valve leaflets of an aortic valve in view of replacement thereof with a valve prosthesis implanted cutaneously) or to interventions in venous contexts, for example in the technique known as "valvulotomy of the saphenous vein" for providing arterial bypasses for lower limbs in critical ischaemia, using the devalvulated saphenous vein as arterial prosthesis in situ.

The saphenous vein is a vessel that on average has a diameter of half a centimetre and a length that extends from the medial malleolus to the groin. Devalvulation in effect becomes necessary for arterializing the saphenous vein, which after the intervention no longer belongs to the venous system, but rather to the peripheral arterial system. Devalvulation is in general carried out blind, i.e., without any radiological control or guide, with valvulotomy catheters inserted in the course of an open surgery and not an endovascular surgery. Valvulotomy catheters may be of a resterilizable or of a disposable type, and have a diameter ranging between 3 mm and 7 mm and the length referred to above. Radiological check is carried out at the end of the intervention (which is an open intervention and not an endovascular intervention [???-E' GIA¹ STATO DETTO POCO SOPRA]) to verify the perviousness of the arterial bypass with the devalvulated saphenous vein left in situ.

In one embodiment, the solution described herein tackles the specific problems linked to the execution of a valvulotomy in a venous context, such as for example the proximal segment of the internal jugular vein. In said context, it is hence a matter of carrying out devalvulation of a vein affected by the presence of a malformed valve. Devalvulation does not have the purpose of arterializing a vein, but rather the purpose of enabling again a regular passage of the cerebral blood in the internal jugular vein. The intervention can be carried out by endovascular route and not as open surgery, under radiological control or even high- resolution ecographic control. The introduction route can be the femoral vein, with the use of catheters of a length ranging between 100 cm and 120 cm, capable of sliding on a guide.

In various embodiments, there is envisaged the use of a catheter that can be governed from outside for enabling deployment of a valvulotomy instrument and of a basket for collection of the residue of devalvulation.

In various embodiments, the diameter of the deployed valvulotome ranges between 6 and 12 mm. In various embodiments, the device is of a self-centring and self-sizing type.

Brief description of the annexed representations The invention will now be described, purely by way of non-limiting example, with reference to the annexed representations, wherein:

- Figure 1 and Figure 2 have already been described previously;

- Figure 3 is a schematic representation of the modalities of use of the device described herein; and

- Figures 4 and 5 are two views in longitudinal section of part of the device illustrated herein, represented in a condition of introduction and in a condition of use.

Detailed description of embodiments

In the ensuing description, various specific details are illustrated aimed at an in-depth understanding of the embodiments. The embodiments can be obtained without one or more of the specific details, or with other methods, components, materials, etc. In other cases, known structures, materials, or operations are not illustrated or described in detail so that various aspects of the embodiments will not be obscured.

Reference to "an embodiment" or "one embodiment" in the context of this description is intended to indicate that a particular configuration, structure, or characteristic described in relation to the embodiment is comprised in at least one embodiment. Hence, phrases such as " in an embodiment" or "in one embodiment" that may be present in various points of this description do not necessarily refer to one and the same embodiment. Furthermore, particular conformations, structures, or characteristics can be combined adequately in one or more embodiments.

The references used herein are merely for convenience and hence do not define the sphere of protection or the scope of the embodiments.

In Figures 3 to 5 the reference number 10 designates as a whole a device for performing a valvulotomy of a malformed valve V present, for example, in the proximal segment of the internal jugular vein IJV. The intervention of valvulotomy involves the at least partial ablation of the corresponding valve leaflets and/or of possible nonfunctioning cusps acting as diaphragm that hinders the flow into the lumen of the vein IJV.

In one embodiment, the device 10 is located at the distal end of an introduction catheter C (only partially visible in Figure 3) so as to enable its positioning via catheterism in a jugular vein at the distal jugular lumen (in the vicinity of the confluence of the brachiocephalic trunk) . In one embodiment, the catheter C for positioning the device 10 is compatible with introducers of 6-8 French; it is flexible, slides smoothly, is not subject to kinking even in curvilinear stretches, and has a length for example of 100-120 cm.

In the embodiment illustrated, the device 10 basically comprises two elements:

an ablation instrument 12, designed to perform the cutting operation that underlies valvulotomy; and

a collection element 14 having an apertured structure, substantially resembling that of a basket, having the function of collecting the valve leaflets or, in any case, the residue liberated by the action of ablation performed by the instrument 12, preventing said residue, entrained by the blood flow BF, from possibly flowing in an undesirable way towards the thorax with the risk of producing pulmonary embolism.

As may be appreciated more clearly from the view of Figure 3, in the condition of use, the two elements 12 and 14 are designed to be set straddling the area V where valvulotomy is carried out.

Said straddling arrangement envisages that the cutting tool 12 and the "basket" 14 will be set, respectively, in a distal position and in a proximal position with respect to the region V. The terms "distal" and "proximal" are used herein with reference to the direction of introduction of the catheter C and hence, generically, in an anatomical sense: it will be appreciated in fact that the blood flow ???BV [?BF] in a venous vessel is in the distal-proximal direction, i.e., from the periphery towards the centre of the body.

The instrument 12, the characteristics of which will be illustrated more clearly in what follows, has on its proximal side - hence in a position facing the region V in the condition of use of Figure 3 - one or more cutting edges 120.

Once the cutting tool 12 and the collection element 14 are set straddling the region V, by acting on the catheter C so as to recall the device 10 in a proximal direction, i.e., in the direction of extraction of the catheter, it is possible to cause the cutting edge 120 to act on the valve V, thus performing the desired action of valvulotomy. The action in question can also lead to a rotation of the catheter C about its axis.

The residue of valvulotomy (valve leaflets, etc.) thus liberated are entrained by the blood flow BF into the basket-like element 14, the apertured structure of which, for example a meshwork structure, offers a minimum resistance to the blood flow but withholds within it whatever is entrained by the blood flow itself .

Figures 4 and 5 illustrate a possible embodiment of the device 10 aimed at taking into account the fact that:

the device 10 is positioned on the site of valvulotomy causing it to advance through the vascular system of the patient (for example, following upon insertion in the right or left femoral vein) ; and once valvulotomy has been performed, the device 10 is extracted from the body of the patient causing it to return along the same path that it had taken to reach the valvulotomy site.

In the examplary of embodiment illustrated in Figures 4 and 5, the reference number 100 designates a tubular core that can correspond in effect to a tubular core of flexible material (for example, plastic material) constituting the core of the catheter C as a whole.

Slidably mounted within the core 100 is a filiform actuating element 102. The element 102 may be manoeuvred, causing it to slide in a longitudinal direction with respect to the core 100, by acting at the proximal end of the catheter C via an actuating device 104, which will be described more fully in what follows .

In a similar way, slidably fitted on the tubular core 100 is a tubular sheath 106, which also can be made to slide longitudinally with respect to the core 100 by acting on the actuating device 104, situated at the proximal end of the catheter C.

It will be appreciated that the technique of bringing about operation of elements situated at the distal end of a catheter via actuating devices situated at the proximal end of the catheter itself with said devices that are able to cause longitudinal sliding, with respect to the catheter, of filiform and/or tubular actuating elements is a technique widely used in numerous sectors of non-invasive surgery (for example, for the implantation of coronary stents or similar devices), which renders a more detailed description herein superfluous.

In the example illustrated, the actuating wire 102 is connected at its distal end to a spindle-shaped or ogival hollow capsule 110. The capsule 110 hence forms a sort of cap having a shape approximately resembling the head of a mushroom and is hence able to cover with its proximal edge a cutting tool, i.e., the valvulotome proper, that carries the cutting edge or edges 120. In the example illustrated, the valvulotome comprises a hub 120a fixed at the end of the core 100 and a plurality of spokes 120b extending from the hub 120a and carrying at their ends a cylindrical shroud 120c, the proximal rim of which constitutes precisely the cutting edge 120.

In the condition of introduction represented in Figure 4 the valvulotome with the cutting edge 120 is inserted (i.e., "slid") into the proximal edge of the capsule 110. In this condition, the capsule 110 hence covers the valvulotome and keeps the cutting edge 120 in a condition where it is covered with respect to the outside: the edge 120 is thus prevented from possibly damaging the tissue with which the device 10 comes into contact whilst the device itself is made to advance towards the site of valvulotomy.

The sheath 106 has at its distal end a slightly widened part 106a with the function of withholding the basket-like element 14 in a radially contracted condition while the device 10 is made to advance towards the site of valvulotomy in the condition represented in Figure 4.

The various details of the solution illustrated herein are on the other hand to be considered as being provided purely by way of example and are certainly not imperative .

For example, the sheath 106 could have a non- widened distal end (i.e., be a sheath of constant diameter throughout its length, with the basket-like element 14 housed in a corresponding annular slot formed in the core element 100) . Likewise, the capsule 110 could have a different shape, for example a prismatic shape and have a distal end with a conformation different from the rounded conformation illustrated herein, designed to facilitate advance of the device 10 towards the site of valvulotomy.

The embodiment considered herein enables the operator to introduce the device 10 into the body of the patient and cause it to advance towards the site of valvulotomy in a condition of minimal resistance to advance, i.e., with the capsule 110 that exerts its ogive effect, keeping, in a covered condition, the valvulotome and the sheath 106 that withholds the basket-like element 14 in the a radially contracted condition shown in Figure 4.

Once positioning on the valvulotomy site V has been achieved (a condition that can be detected, for example, thanks to the presence of one or more radio- opaque markers 112 present on the device 10, for example in an intermediate position between the instrument 12 and the basket-like element 14), by acting on the device 104 the operator can deploy both the instrument 12 and the basket element 14, bringing them into the operating condition illustrated in Figure 5.

In the embodiment illustrated herein, deployment of the element 12 is obtained by the fact that the valvulotome is at least partially extracted from the capsule 110 in such a way that the cutting edge 120 projects on the outside of the edge of the capsule so as to be able to exert the desired cutting action according to the criteria illustrated schematically in Figure 3.

This result can be obtained as a consequence of a relative movement of the core 100 and of the wire 102 such as to cause (as may be appreciated directly from the comparison of Figures 4 and 5) the core 100, on which the valvulotome is fixed, to recede with respect to the wire 102, which carries the capsule 110, hence causing the cutting edge 120 to project with respect to the capsule 110. Reference to "relative movement" takes into account the fact that the same result can also be obtained by causing the wire 102, which carries the capsule 110, to advance with respect to the core 100, on which the valvulotome is fixed, or else by moving both the core 100 and the wire 102.

Once again, it is here assumed that deployment of the valvulotome involves only a (relative) sliding with respect to the capsule 110. In various embodiments (in addition or as an alternative to said movement of relative sliding) it may be envisaged that, in the condition of introduction of Figure 4, the capsule 110 will keep the valvulotome in a radially contracted condition, facilitating advance towards the valvulotomy site, and that then the capsule, disengaging the valvulotome, will enable the valvulotome itself to expand radially.

In the examplary of embodiment considered here, such a mechanism of deployment is adopted for the basket-like element 14. For example, in one embodiment, the basket-like element 14 can be made of a superelastic material and/or a material with characteristics of shape memory such as the material known as Nitinol. Once freed from the action of containment performed by the sheath 106a, which is retracted by acting on the sheath 106, the basket-like element 14 reaches the desired deployed condition.

The basket-like element 14 is particularly suited to being made of materials such as Nitinol and with a mesh-like structure, which, but for the general divergent shape that is preferably slightly bowl-like in the deployed condition, has for some time been used both for angioplasty stents and for providing prosthetic cardiac valve structures designed to be implanted by percutaneous route, i.e., with sutureless techniques .

In the examplary of embodiment illustrated herein, the basket-like element 14 has a proximal shank 140, which, when the sheath 106 itself is drawn back, remains in any case inserted in the sheath 106 itself whilst the distal part of the element 14 opens like a basket towards the instrument 12.

Both in the case of the element 12 and in the case of the element 14, instead of a mechanism of deployment on the basis of characteristics of elasticity/shape memory, it is possible to use a mechanism of deployment of a positive type, controlled for example via a balloon mounted at the distal end of the catheter.

In the embodiment here considered, the passage from the condition of introduction (represented in Figure 4) to the deployed condition of use (represented in Figure 5) is at least partially reversible both as regards the instrument 12 and as regards the basket- like element 14.

Once valvulotomy is completed, the device 10 can thus be at least in part brought back to the condition of Figure 4, i.e., with the cutting edge 120 once again hidden away inside the capsule 110 so as to be able to extract the device 10 from the body of the patient, preventing undesirable phenomena of cutting along the return path.

This characteristic proves otherwise advantageous since, in the case where the procedure of valvulotomy has for some reason to be aborted, it enables convenient extraction of the device 10 from the body of the patient.

Once the basket-like element 14 has received within it the valve leaflets and/or any other residue of the operation of valvulotomy, it can no longer be recalled into the radially contracted condition of Figure 4. In any case, the movement of extraction in reverse of the basket-like element 14, also in the radially expanded condition, does not in general cause undesirable phenomena for the vessels involved in the catheterism. This applies above all in the case where the basket-like element 14 is made of (super-) elastic material that can easily yield without giving rise to damage to the walls of the vessels traversed during extraction of the device 10. In this regard, a beneficial role is played also by the general divergence of the basket-like element 14, facing in a distal direction: during the movement of recall, the basket-like element 14 hence has a "streamlined" shape such as to facilitate sliding along the wall of the vessels during the movement of extraction.

At the same time it will be appreciated that the proximal edge of the capsule 110, designed to cover the valvulotome (see Figure 4) has a rounded external shape, which is also "streamlined" and such as to facilitate sliding along the wall of the vessels both during the movement of advance of the device 10 towards the site of valvulotomy and during the return movement of extraction.

The control device 104 can be built (according to criteria in themselves known) in such a way as to act on the core 100, on the wire 102, and/or on the sheath 106 so as to control deployment of the cutting tool 12 and of the collection element 14, either sequentially, i.e., at successive moments, or simultaneously, i.e., all at the same time. The latter solution can be advantageous in so far as it ensures that the cutting edge 120 is in a condition of exerting the cutting action only when the collection element 14 is also deployed and able to collect the corresponding residue, thus preventing it from being drawn along by the blood flow BF.

For example, the device 104 can have a general pistol-shaped configuration and comprises a lever 1042, similar to the brake lever of a bicycle, which can be operated for controlling simultaneously deployment of the cutting tool 12 and of the collection element 14. Said trigger-like shape or brake-lever shape enables control in a regulated and precise way of exit of the cutting formation 120 from the capsule 110.

Once again with known means (for example, by mounting the sheath 106 and the element 14 on an intermediate tubular sheath - not expressly illustrated in the drawings - slidably fitted longitudinally on the core 100 under the control of an adjustment wheel 1044 or equivalent member) it is possible to render selectively adjustable - before and/or after deployment - the distance between the cutting tool 12 and the collection element 14 (see, for example, the distance D of Figure 5) so as to adapt it in an optimal way to the requirements of surgical intervention.

In other embodiments, the ring or wheel 1004 can be doubled and comprise, in addition to a part designed to adjust the distance between the elements 12 and 14, a part designed to enable choice of simultaneous deployment of the cutting tool 12 and of the basket- like element 14.

In this way, both during entry and during exit, the catheter will present small overall dimensions thus reducing its invasiveness to a minimum. Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary, even significantly, with respect to what has been illustrated herein purely by way of non-limiting example, without thereby departing from the scope of the invention, as defined by the annexed claims .

Claims

1. A venous valvulotomy device for introduction via an introduction catheter (C) , the device including:

- a cutting tool (12) having at least one cutting formation (120) to perform a valvulotomy action, and

- a collection element (14) of the valvulotomy residue arranged at a proximal location with respect to said cutting tool (12) to collect said valvulotomy residue transported by blood flow from said cutting tool (12) .

2. The device of claim 1, wherein said collection element (14) has an apertured structure to permit unimpeded flow of blood through the collection element (14) .

3. The device of any of the previous claims, wherein at least one (14) of said cutting tool (12) and said collection element (14) is expandable between a radially contracted introduction condition into a patient's body and a radially expanded condition to perform valvulotomy.

4. The device of claim 3, wherein said at least one (14) of said cutting tool (12) and said collection element (14) includes an elastic material, whereby expansion towards said radially expanded condition takes place due to elasticity.

5. The device of claim 3 or claim 4, wherein said at least one (14) of said cutting tool (12) and said collection element (14) has an associated radial confinement element (106a) for confinement thereof in said radially contracted condition, said radial confinement element (106a) disengageable from said at least one (14) of said cutting tool (12) and said collection element (14) to permit expansion thereof towards said radially expanded condition.

6. The device of any of the previous claims, wherein said cutting tool (12) has an associated cover member (110) to keep said at least one cutting formation (120) covered with respect to the outside during introduction into a patient's body and to selectively uncover said at least one cutting formation (120) to perform said valvulotomy.

7. The device of claim 6, wherein said at least one cutting formation (120) and said cover member (110) are capable of a relative sliding movement longitudinally of said introduction catheter (C) .

8. The device of claim 6 or claim 7, wherein said cover member (110) has a general cap-like configuration with said at least one cutting formation (120) selectively insertable and extractable with respect to said cap.

9. The device of any of claims 6 to 8, wherein said cover member (110) has an ogive-like profile to facilitate advance towards a valvulotomy site.

10. The device of any of claims 6 to 9, wherein said at least one cutting formation (120) has a general ring-like configuration.

11. The device of any of the previous claims, wherein said collection element (14) has a general basket-like configuration opening in a distal direction with respect to the device (10).

12. The device of any of the previous claims, including a control device (104) at a proximal position with respect to said introduction catheter (C) and including at least one of:

- a control member (1042) to produce sequentially or simultaneously the deployment of said cutting tool (12) and said collection element (14) between an introduction condition into a patient's body and a deployed condition to perform valvulotomy, and

an adjustment member (1044) to adjust the distance (D) between said cutting tool (12) and said collection element (14).

13. A kit including:

- a device (10) according to any of claims 1 to 12, and

- instructing means for the use of the device for valvulotomy in a venous context, preferably in the proximal segment of the internal jugular vein.