WO2011144240A1

WO2011144240A1 - Embolic protection catheter

Info

Publication number: WO2011144240A1
Application number: PCT/EP2010/056941
Authority: WO
Inventors: Miles Dalby
Original assignee: Joline Gmbh & Co. Kg
Priority date: 2010-05-20
Filing date: 2010-05-20
Publication date: 2011-11-24

Abstract

A catheter (10) for insertion and deployment of a dilation balloon (19) inside a blood vessel (12) comprises a catheter body (14), a deployment section (18), provided on said catheter body (14), which deployment section (18) comprises said dilation balloon (19) and is adjusted for housing and deploying said dilation balloon (19), and a filter section (21), provided on said catheter body (14), which filter section (21) comprises an embolic protection filter (29) with a mouth opening (36). Said filter section (21) comprises a cover sheath (22) adjusted for exclusively housing and deploying said embolic protection filter (29). Said cover sheath (22), for deploying said embolic protection filter (29), is shifted such that it first uncovers the embolic protection filter (29) and then the mouth opening (36) and, for re-sheathing said embolic protection filter (29), is shifted such that it first covers the mouth opening (36) and then at least a part of the embolic protection filter (29).

Description

Embolic protection catheter

The present invention concerns a catheter for insertion and deployment of a dilation balloon inside a blood vessel, the catheter comprising a catheter body, a deployment section, provided on said catheter body, which deployment section comprises said dilation balloon and is adjusted for housing and deploying said dilation balloon, and a filter section, provided on said catheter body, which filter section comprises an embolic protection filter with a mouth opening.

Such catheters are known, for example, from US 2005/0137696 Al. US 2005/0137696 Al describes an apparatus, for protecting a patient against embolization during endovascular replacement of the patient's heart valve, the apparatus comprising a deployment section with a dilation balloon and, located downstream of said deployment section, an embolic protection filter with a mouth opening.

Generally, for endovascular replacement of a heart valve, for example a stenosed aortic valve, in a first step the calcified leaflets of the valve are dilated using a balloon catheter. This procedure is termed "valvuloplasty". Then, in a second step, an endo- luminal prosthesis is deployed within the residual opening widened in the first step, excluding the functionally compromised native heart valve from the blood flow and functionally replacing it.

Valvuloplasty as well as valve replacement can be carried out either in a retrograde or antegrade procedure. For aortic valve replacement applying a retrograde procedure, the catheter is inserted into the aortic valve via the aorta, the catheter's distal end pointing in direction of the heart. In the corresponding antegrade procedure, the catheter is inserted through an incision in the heart's apex, into the left ventricle and further into the aortic valve, the catheter's distal end pointing in direction of the aorta.

Irrespective of which of these two techniques is applied, one of the major drawbacks of endoluminal treatment of heart valves in general and calcified aortic valves in particular is the release of calcified matter from the leaflets of the valve into the blood stream. These particles are carried downstream by the blood flow, potentially embolizing downstream vessels, for example in the brain.

It is established among surgeons that debris may be released from calcified leaflets during placement of an endoluminal prosthesis inside an aortic valve and that, hence, precautions for embolic protection should be taken during this step. In fact, however, substantial release of debris occurs already during balloon pre-dilation of the aortic valve, i.e. when cracking open the calcifications on the leaflets of the aortic valve. In addition, every step that includes frictional contact between a catheter- surface and the leaflets of the aortic valve may trigger release of debris.

A number of embolic protection systems do exist, which are adjusted for removing stenotic debris from the vasculature during either retrograde or antegrade balloon dilation of constrictions or placement of endoluminal prostheses. The majority of these systems, however, employ several catheters, which have to be used in parallel or in succession. This makes the application of embolic protection error-prone and also challenging in surgical terms.

The apparatus known from US 2005/0137696 Al, mentioned at the outset, is intended for solving this problem by combining a dilation balloon and an embolic protection filter in one device.

When using the known apparatus in valvuloplasty, first, the catheter is inserted through the leaflets of an aortic valve in a retrograde manner. Then a cover sheath is retracted in proximal direction past the leaflets of the aortic valve, releasing the dilation balloon and the embolic protection filter. After this, the dilation balloon is inflated. Embolizing material dislodged from the patient's heart valve during inflation of the dilation balloon is carried downstream by the blood flow and caught within the embolic protection filter. After finishing valvuloplasty, the embolic protection filter is folded by shifting the cover sheath such that it first covers the embolic protection filter and then its mouth opening. Accordingly, the sheath compresses and houses the embolic protection filter and, ideally, the debris contained within the embolic protection filter.

However, a principle problem when using such catheter is that, when compressing the embolic protection filter in the manner described above, debris may be squeezed out of the filter in a "toothpaste"-like manner, releasing it into the vasculature.

Further, the cover sheath of the known catheter covers both the embolic protection filter and the dilation balloon. As dilation balloons, in particular when adjusted for valvuloplasty, are relatively bulky, the overall outer diameter of the catheter is relatively large. Hence, the insertion of such catheter past a constriction is accompanied by intense frictional contact between the catheter surfaces and the constriction, at least potentially entailing the release of debris from the constriction.

Moreover, frictional contacts between the catheter surface and the calcified leaflets of the aortic valve occur for a minimum of two times without embolic protection being established, namely once during catheter insertion and once during retraction of the cover sheath. During both manipulations, the embolic protection filter is not inflated and, hence, has no function.

Hence, debris particles are potentially released into the vasculature before and after establishment of embolic protection.

In this connection, US 2007/0142858 Al discloses a catheter comprising a balloon- expandable prosthesis crimped on a dilation balloon. The catheter, further, comprises an embolic protection filter, provided proximal to said endoluminal prosthesis. In order to avoid release of debris during re-sheathing of the embolic protection filter, either a reservoir for debris-containment is provided in the catheter body, or the embolic protection filter is amphora-shaped, comprising a necked mouth opening. The necked mouth opening is intended to be closed prior to complete compaction of the embolic protection filter within the cover sheath.

In this case, the disadvantage is that, despite the catheter's enhanced storage capacity for debris, such debris may still escape from the embolic protection filter once the containment capacity of the reservoir or the amphora's receptacle is exceeded by the amount or size of debris released during valvuloplasty.

Further, the known catheter has a relatively large diameter as the cover sheath covers both the prosthesis on the dilation balloon and the filter section. Moreover, also in this case, the cover sheath has to be retracted past material of the constriction to be treated. Hence, the catheter frictionally contacts the material of the constriction at least twice when the embolic protection filter is not effective, as discussed above in connection with the catheter of US 2005/0137696 Al.

While the catheters according to US 2005/0137696 Al and US 2007/0142858 Al are configured for performing retrograde procedures, other systems, for example described in WO 2006/031648 A2, can be utilized for antegrade procedures, in particular valve replacement.

WO 2006/031648 A2 describes a catheter comprising a balloon-expandable prosthesis crimped on a dilation balloon. An embolic protection filter is located distal to the endoluminal prosthesis. Endoluminal prosthesis and dilation balloon are constrained within a common cover sheath. For activation of embolic protection, this cover sheath is retracted past the leaflets of the stenosed aortic valve to be treated. After valve replacement, the cover sheath is advanced in distal direction for re-sheathing the embolic protection filter, first compressing the mouth opening of the embolic protection filter and then the embolic protection filter itself.

Also this catheter has a large diameter, owing to the fact that its cover sheath covers both the embolic protection filter and the prosthesis crimped on the dilation balloon. This large diameter may result in debris release from the aortic valve to be treated already during catheter insertion.

Moreover, using the catheter of WO 2006/031648 A2 necessitates multiple steps involving friction between the leaflets of the aortic valve and the catheter prior to activation of the embolic protection filter.

In view of the above, it is an object of the present invention to improve the known catheters such that, compared to known devices, the release of debris into the blood stream can be prevented more efficiently. This object and other objects of the invention are achieved with a catheter of the kind described at the outset, wherein between deployment section and filter section said catheter body comprises means that allow inflation and deflation of embolic protection filter without influencing dilation balloon, said means preferably comprising a shifting section for receiving a cover sheath adjusted for exclusively housing and deploying said embolic protection filter, or an opening receiving at least one actuation wire connected to a wire loop which in turn is connected to mouth opening in a draw-string like manner.

Thus, the new catheter allows either a filter cover sheath or actuating wires and wire loops of the embolic protection filter to be placed in such intermediate section such that neither during inflation nor during deflation of said embolic protection filter said dilation balloon is acted upon. This allows to leave the dilation balloon free from any cover sheath or other actuating means, thereby reducing the diameter of the catheter.

According to a first embodiment, said filter section comprises a cover sheath adjusted for exclusively housing and deploying said embolic protection filter, and wherein said cover sheath, for deploying said embolic protection filter, is shifted such that it first uncovers the embolic protection filter and then the mouth opening and, for re- sheathing said embolic protection filter, is shifted such that it first covers the mouth opening and then at least a part of the embolic protection filter.

In this connection, the catheter according to the present invention may comprise a "shifting section", provided in between the deployment- and filter section, said shifting section serving to accommodate the cover sheath when the filter is deployed.

A "blood vessel" within the scope of the present invention may be any part of the vasculature of a human or animal, including also such parts of the vasculature, which have been operationally introduced into a patient's body, such as grafts, xenografts or transplants. According to the invention, an "embolic protection filter" is understood to be a structure adjusted for permitting the passage of blood, including plasma and cells, but holding back larger particles or particle aggregates. Such embolic protection filters, which may, for example, have a pore or mesh size of 20 to 500 pm, are extensively known from the art, see for example WO 03/090607 A2 and WO 02/054984 A2, the disclosure whereof is incorporated herein by reference.

In the context of the present invention, the term "upstream", with respect to a blood vessel, describes the direction opposing the blood flow, while the term "downstream" describes the direction following the blood flow.

The term "proximal", with respect to a catheter, describes the direction towards an operator handling the catheter, while the expression "distal", with respect to a catheter, describes the direction towards the catheter tip, facing away from the operator.

Even though the following description mainly relates to the treatment of calcified aortic valves, it is understood that catheters according to the invention may also be utilized for treating other constrictions, such as other heart valves, stenoses comprised of hard matter, occurring in the course of atherosclerosis, or emboli comprised of soft matter. Such emboli may be, for example, protein or fat aggregates, cells, tissue or mixtures thereof.

The novel catheter has several advantages over known catheters. In particular, it enables safe containment of the debris caught in the embolic protection filter during balloon dilation of a constriction and re-sheathing of the embolic protection filter.

This is achieved by the cover sheath first covering the mouth opening and then the embolic protection filter. Accordingly, the mouth opening of the embolic protection filter is closed off from the vasculature even before substantial compression of the embolic protection filter occurs. Consequently, a squeezing out of debris is efficiently prevented.

Moreover, the overall diameter of the catheter system is reduced compared to the catheters of the prior art described hereinabove.

Dilation balloons, in particular when adjusted for valvuloplasty, are relatively bulky even in their folded state. The cover sheaths of the catheters of the prior art cover both the respective filter sections and dilation balloons. These cover sheaths, hence, add to the diameter of the dilation balloons, defining the maximum diameter of the overall catheter.

The cover sheath of the catheter according to the present invention exclusively covers the filter section. It does therefore not add to the diameter of the dilation balloon.

Owing to the smaller diameter of the catheter according to the present invention, the insertion of the catheter through the residual opening of a constriction is made easier, reducing the amount of frictional contact between the catheter surface and the material forming the constriction. Consequentially, the release of debris during catheter placement, during which the embolic protection filter generally is still compressed within the cover sheath, is reduced.

In this connection, the release of debris from the constriction prior to the unfolding of the embolic protection filter is reduced still further owing to the fact that the cover sheath, during release of the embolic protection filter, does not come into physical contact with the constriction, thereby reducing the steps involving friction between the surfaces of the catheter and the constriction material prior to unfolding of the embolic protection filter.

Thus, the object underlying the invention is achieved completely.

In particular, according to a first variant of the first embodiment, the present inven- tion relates to a catheter for retrograde insertion and deployment of a dilation balloon inside a heart valve, the catheter comprising a catheter body, a deployment section, provided near a distal end of said catheter body, which deployment section comprises said dilation balloon and is adjusted for housing and deploying said dilation balloon, and a filter section, provided on said catheter body proximal to said deployment section, which filter section comprises an embolic protection filter with a distal mouth opening, wherein said filter section comprises a cover sheath adjusted for exclusively housing and deploying said embolic protection filter, wherein said cover sheath, when housing said embolic protection filter, extends proximal of said deployment section, and wherein said cover sheath, for deploying said embolic protection filter, is shifted in distal direction, such that it first uncovers the embolic protection filter, and then the mouth opening and, for re-sheathing said embolic protection filter, is shifted in proximal direction, such that it first covers the mouth opening and then at least a part of the embolic protection filter.

The advantage of retrograde treatment, in particular of aortic valves, is that this procedure is less invasive than antegrade treatment. Only a minor incision, for example in one of the femoral arteries, is necessary to insert the catheter.

Moreover, according to a second variant of the first embodiment,the present invention relates to a catheter for antegrade insertion and deployment of a dilation balloon inside a heart valve, the catheter comprising a catheter body, a filter section, provided near a distal end of said catheter body, which filter section comprises an embolic protection filter with a proximal mouth opening, and a deployment section, provided on said catheter body proximal to said filter section, which deployment section comprises said dilation balloon and is adjusted for housing and deploying said dilation balloon, wherein said filter section comprises a cover sheath adjusted for exclusively housing and deploying said embolic protection filter, wherein said cover sheath, when housing said embolic protection filter, extends distal of said deployment section, and wherein said cover sheath, for deploying said embolic protection filter, is shifted in proximal direction, such that it first uncovers the embolic protection filter and then the mouth opening, and, for re-sheathing said embolic protec- tion filter, is shifted in distal direction, such that it first covers the mouth opening and then at least a part of the embolic protection filter.

Antegrade treatment, in particular of aortic valves, provides the advantage of better manual control by the surgeon performing the operation. In addition, the crossing of the aortic valve is simpler in downstream direction than upstream direction.

It is generally preferred if the embolic protection filter is self expandable and, upon deployment, radially contacts the walls of the blood vessel.

Such self-expanding embolic protection filter may, for example, comprise one or more self-expandable reinforcing elements, which are adjusted to expand in such a way, that the embolic protection filter contacts the walls of the blood vessel to be treated in a full circle, not allowing blood, and thus debris transported by such blood, to bypass.

Moreover, the self-expandable elements may comprise gliding surfaces coated with, for example, PTFE, in order to reduce friction between the cover sheath and the self- expandable elements during cover sheath retraction and re-advancement.

In order to fulfil their function, the self-expandable elements are firmly connected to the catheter body and, extend from the catheter body in a manner allowing their safe release and re-constraining as well as allowing the embolic protection filter to contact the vessel walls in a full circle.

These goals may be achieved with self-expandable elements fastened to the catheter body in a centrical (symmetric) or eccentrical (asymmetric) manner. Such configurations are extensively known from the art and are described for example in above mentioned WO 02/054984 Al and WO03/090607 Al.

Further, it is preferred if the embolic protection filter comprises two or more ra- diopaque markers.

Such radiopaque markers, preferably, are provided on parts of the embolic protection filter that, when the embolic protection filter is deployed, are in lateral positions and that, when the embolic protection filter is constrained within the cover sheath, are shifted to more central positions.

Hence, the operator monitoring the intervention via x-ray can check the successful deployment and re-compression of the embolic protection filter, made visible by the shift in the position of the radiopaque markers with respect to each other.

It is preferred if said catheter comprises one or more actuating wires connected to said cover sheath.

Such actuating wires, in the scope of the present invention, serve to actuate the mouth opening, for example, by shifting the cover sheath such that it either uncovers or re-sheathes the embolic protection filter. This is achieved by the operator either pushing or pulling the actuating wires, respectively.

The advantage here lies in the fact that, using actuating wires, the cover sheath can be actuated in a comparably simple manner without the actuating mechanism interfering with other structures provided on the catheter.

The actuating wires may, for this purpose, be directly connected to the cover sheath. Alternatively, the actuating wires may contact the cover sheath indirectly, for example by means of an actuating element. This actuating element serves to transmit power to the cover sheath, such power exerted on the actuating wires by pushing or pulling these.

When actuating wires are asymmetrically distributed with respect to the cross section of the catheter, force exerted on the actuating elements and, hence, the cover sheath might result in tilting of the cover sheath around the catheter's longitudinal axis. This may especially be the case in embodiments with only one actuating wire provided in the catheter.

For the purpose of preventing such tilting of the cover sheath, the actuating element may comprise guiding means, such as one or more protrusions running in recesses provided in the catheter body.

According to a preferred embodiment, the catheter comprises a channel adjusted for de-airing. In this connection, it is especially preferred if the cover sheath comprises secondary openings.

Within the scope of the present invention, the term "secondary openings" relates to lateral pores or holes provided in the cover sheath, the pores or holes, for example, having a diameter in the range of 20 to 500 pm.

During assembly and storage, the filter section may comprise a certain volume of air or protective gas, enclosed within the cover sheath and the catheter body.

Such volumes of gas could, when released into the blood stream, under certain circumstances result in gas embolisms, closing off downstream vessels from blood flow.

In order to avoid even smallest possibilities for this danger, prior to using the catheter, the de-airing channel is used to flood the filter section with physiologically acceptable liquids, such as physiological saline.

The gas contained in the filter section is forced out through the secondary openings of the cover sheath. Alternatively, the catheter, prior to its use in a patient, is immersed in a physiologically acceptable liquid, whereupon the gas inside the filter section is aspirated through the de-airing channel, and liquid intruding through the secondary openings floods the interior of the filter section.

In addition, the effect of gas-bubbles remaining inside the catheter may be ameliorated by keeping, prior to its use, the catheter in an atmosphere of physiologically acceptable gas with high water solubility, such as C0₂. Remaining (small) bubbles of such gas dissolve in the blood stream relatively quickly, reducing the risk of gas embolism.

The present invention, according to a second embodiment, further concerns a catheter for insertion and deployment of a dilation balloon inside a blood vessel, the catheter comprising a catheter body, a deployment section, provided on said catheter body, which deployment section comprises said dilation balloon and is adjusted for housing and deploying said dilation balloon, and a filter section, provided on said catheter body, which filter section comprises an embolic protection filter with a mouth opening, wherein said filter section comprises a wire loop, provided at said mouth opening of said embolic protection filter, and one or more actuating wires, connected at their distal ends to said wire loop, and wherein said wire loop is configured such that it opens said mouth opening when said one or more actuating wires are shifted in a first direction and that it closes said mouth opening when said one or more actuating wires are shifted in a second direction, opposite to said first direction.

In this connection, the wire loop, for example, is comprised of an elastic or shape memory material such as Nitinol.

The wire loop is connected to the material of the embolic protection filter, in particular the mouth opening, and serves to expand the embolic protection filter such that it forms a tent-like structure, circumferentially contacting the walls of the blood vessel in which the catheter is inserted.

For example, the wire loop may, in its expanded state, be shaped as a ring, which is either arranged perpendicular or oblique with respect to the longitudinal axis of catheter and blood vessel. The wire loop is connected to the embolic protection filter either in an at least partially slidable or in non-slidable manner.

A slidable connection between embolic protection filter and wire loop is achieved, for example, by accommodating the wire loop or parts thereof in loops of filter material or annular drawstring casings, surrounding the embolic protection filter's mouth opening.

In such case, for example, one or more actuating wires and the larger part of the wire loop, connected to said actuating wires, are comprised in one or more actuating lumens of the catheter body prior to deployment of the embolic protection filter. These one or more actuating lumens comprise one or more lateral openings connecting them with the outside of the catheter body. The wire loop, in its initial position, protrudes through said one or more openings such that a smaller portion of the wire loop, including the embolic protection filter connected to it, resides outside of the lumen on the surface of the catheter body.

For deployment, the one or more actuating wires and, thus, the wire loop are shifted in a direction towards the one or more openings. The wire loop, when exiting the one or more actuating lumens, self expands, thereby unfolding the embolic protection filter into a tent-like conformation such that it contacts the walls of the blood vessel and faces upstream with its mouth opening.

For compression of the embolic protection filter, after valvuloplasty, the one or more actuating wires and, hence, the wire loop are shifted in a direction opposite to the direction of the first shift, thereby retracting the larger part of the wire loop through the one or more openings into the one or more actuating lumens. The wire loop, acting like a draw-string, collapses the mouth opening, thereby closing its upper rim against the catheter body.

Alternatively, the wire loop may not be compressed by partially retracting it into one or more actuating lumens, but by constraining it to the surface of the catheter body. This may be achieved by the wire loop, for example, being non-slidably connected to the material of the embolic protection filter and by the actuating wires describing one or more helical windings about the catheter body. Hence, for compression of the embolic protection filter, the actuating wires are moved such that the wire loop itself is at least partially forced into one or more helical windings around the catheter body, thereby compressing the mouth opening against the catheter body's surface.

It is understood that a catheter according to the present embodiment may be adjusted for antegrade procedures. In this case, it comprises an embolic protection filter, which is provided distal to the catheter's dilation balloon. Alternatively, the embolic protection filter may also be provided proximal to the dilation balloon. In the latter case, the corresponding catheter may be used for retrograde procedures.

The advantage of such catheter lies in the fact that the mouth opening of the embolic protection filter can be closed without necessitating substantial compression of the embolic protection filter. Hence, the escape of debris from the embolic protection filter is efficiently prevented.

Further, the number of steps involving frictional contact between catheter surfaces and the surfaces of a constriction is reduced compared to the prior art. This is the case, because the catheter according to this embodiment of the present embodiment does not comprise a cover sheath at all. Accordingly, during filter deployment, no cover sheath has to be slid past the material of the constriction. Hence, embolic protection is made even more efficient.

Moreover, owing to the fact that the catheter lacks a cover sheath, it has a smaller diameter compared to prior art catheters.

It goes without saying that the features named above and those still to be explained below can be used not only in the respectively specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention.

Further features are disclosed in the figures and the corresponding detailed description.

Several embodiments of the invention are illustrated in the figures and explained in more detail in the following description. In the figures:

Fig. 1 shows, in schematic longitudinal section, a catheter according to a first variant of the first embodiment of the present invention, the catheter being advanced through an aortic valve in retrograde manner;

Fig. 2 shows the catheter of Fig. 1 in cross-section along a plane II-II as indicated in Fig. 1;

Fig. 3 shows, in enlarged view, a schematic longitudinal section of a part of the catheter shown in Fig. 1;

Fig. 4 shows the catheter as in Fig. 1, but with the cover sheath being distally advanced from its initial position;

Fig. 5 shows the catheter as in Fig. 4, but with an inflated dilation balloon; shows the catheter as in Fig. 5, but with the cover sheath being retracted into its initial position; shows, in schematic longitudinal section, a catheter according to a second variant of the first embodiment of the present invention, the catheter being advanced through an aortic valve in antegrade manner; and Fig. 8 shows, in schematic side view, a catheter according to a second embodiment of the present invention, the catheter being advanced through an aortic valve in antegrade manner.

Fig. 1 shows in schematic side view a longitudinal section of a catheter 10 according to a first variant of a first embodiment of the present invention. Fig. 1, as well as Figs. 2 to 8, is not drawn to scale.

Catheter 10 is inserted via guide wire 11 into an aorta 12, and through the leaflets of a calcified aortic valve 13.

Such calcified aortic valve 13 may be treated by dilation, cracking open the calcifications present on the leaflets of aortic valve 13. With such method, the flexibility of the leaflets and, hence, the function of aortic valve 13 may be re-established. Recent years have shown, however, that such dilated aortic valves are highly prone for re- calcification, making necessary further interventions. For this reason, nowadays dilation of the aortic valve 13 is often performed in combination with the implantation of an endoluminal aortic valve prosthesis. Also in such cases, however, the aortic valve 13 is usually pre-dilated in order to allow the passage of the relatively bulky endoluminal aortic valve prosthesis.

All agitation steps involving the leaflets of the calcified aortic valve 13 may cause release of calcified material into the patient's blood stream. This danger is not restricted to the steps of balloon dilation and placement of endoluminal valve prostheses. Release of calcified material into the blood stream may already occur durig insertion of the catheter due to the friction of catheter components with the surfaces of the aortic valve's leaflets, making necessary embolic protection.

For such purpose, novel catheter 10 may be used.

According to the first embodiment, catheter 10 is placed in a retrograde manner, entering the aortic valve 13 in upstream direction, coming from aorta 12. Hence, the distal end of catheter 10 is facing in direction of the heart (not shown).

Catheter 10, within its catheter body 14, comprises a catheter lumen 15, in which guide wire 11 is accommodated. Catheter body 14 at its distal end 16 is provided with a nose cone 17.

A deployment section 18 is provided on catheter body 14 proximal to nose cone 17, which deployment section 18 comprises a dilation balloon 19.

Proximal to deployment section 18, a filter section 21 is provided.

Catheter 10, further, comprises a cover sheath 22, which can be shifted in distal direction of the catheter by an actuating element 23. Actuating element 23 can be actuated via actuating wires 24, accommodated in actuating lumens 25 of catheter body 14.

Further, according to the first embodiment, catheter 10 comprises two actuating wires 24. It is, however, understood that a catheter according to the present invention may comprise only one or any suitable number of actuating wires 24 and actuating lumens 25.

Actuating lumens 25, in a shifting section 26 in between deployment section 18 and filter section 21, are laterally open, forming guiding recesses 27. In these guiding recesses 27 protrusions 28 of actuating element 23 are accommodated, each protrusion 28 contacting one of actuating wires 24, respectively.

In its initial position, shown in Fig. 1, cover sheath 22 is arranged in filter section 21 and covers an embolic protection filter 29. Embolic protection filter 29 is provided with self-expandable elements 31. Further, radiopaque markers 32 are provided on self-expandable elements 31 or are part of self-expandable elements 31.

As long as embolic protection filter 29 is constrained within cover sheath 22, self- expandable elements 31 and, hence, radiopaque markers 32 are constrained to central positions close to one another and to catheter shaft 14. Hence, the unde- ployed state of embolic protection filter 29 can be visualized using x-ray.

Moreover, catheter 10 comprises a de-airing channel 33, provided in catheter body 14 and being open to filter section 21. De-airing channel 33 serves the expulsion or aspiration of gas, for example air, present within filter section 21 prior to the use of catheter 10. Gas present within filter section 21 during the operation might otherwise, after release from cover sheath 22, cause downstream gas-embolism.

For the purpose of de-airing, for example, de-airing channel 33 is flushed with physiological saline solution, water or radiopaque medium, entering filter section 21. While the filter section 21 is flooded with liquid, the gas exits filter section 21 through one or more secondary openings 34 provided in cover sheath 22.

Alternatively, gas contained in the filter section 21 may be aspirated through de- airing channel 33. In this case, the catheter is submerged in saline or another liquid, which enters the filter section 21 through secondary openings 34, flooding the interior of cover sheath 22.

During the insertion of catheter 10 through the residual opening of calcified aortic valve 13, blood flow 35, even though being reduced to some extent, still occurs.

Indicated in Fig. 1 is a plane II-II perpendicular to the longitudinal axis of catheter 10 and crossing through shifting section 26.

A cross section corresponding to said plane II-II is shown in Fig. 2. As can be seen in Fig. 2, catheter body 14 comprises two guiding recesses 27, symmetrically distributed along its circumference. Protrusions 28 of actuating element 23, shown in dashed lines, are accommodated in guiding recesses 27. Each of protrusions 28 is connected to an actuating wire 24.

When actuating element 23 is shifted by means of actuating wires 24, the force exerted on actuating element 23 is symmetrical. The advantage in this case is that tilting of actuating element 23 with respect to the longitudinal axis of catheter body 14 is prevented, which tilting might otherwise result in a failure to properly move actuating element 23.

Hence, a secure motion of actuating element 23 with respect to catheter body 14 is enabled.

Fig. 3 shows, in longitudinal section, an enlarged view of catheter 10 of Fig. 1. The portion shown corresponds to the transition from filter section 21 to shifting section 26.

Provided in catheter body 14, actuating lumens 25 are shown, which are laterally closed in filter section 21 and are laterally open in shifting section 26, forming guiding recesses 27.

Like in Fig. 1 and 2, actuating element 23 is shown to engage guiding recesses 27 via protrusions 28. Protrusions 28 are connected to actuating wires 24 and serve to transmit power from actuating wires 24 onto actuating element 23 and, hence, cover sheath 22.

Thus, when actuating wires 24 are distally advanced by the operator pushing them in direction towards filter section 21, actuating element 23 and cover sheath 22 are distally advanced in direction of filter section 21 as well. Fig. 4 shows catheter 10 as in Fig. 1, but with cover sheath 22 being distally advanced from its initial position, thereby releasing embolic protection filter 29.

Upon release from cover sheath 22, self-expandable elements 31 expand such that they spread embolic protection filter 29 in umbrella-like fashion. Embolic protection filter 29, hence, covers the entire cross section of aorta 12, letting blood flow 35 pass through an upstream mouth opening 36 and through its pores or meshes.

During expansion of self-expandable elements 31, radiopaque markers 32 are shifted from a common, central position to positions laterally spaced apart from each other and from the catheter body. Hence, the operator can see, using x-ray visualization, whether embolic protection filter 29 has been successfully deployed.

Due to the fact that cover sheath 22, according to the present embodiment, is advanced in distal direction for releasing embolic protection filter 29, re-sheathing of embolic protection filter 29, during a later procedural step, can occur in a distal to proximal manner. Hence, cover sheath 22, during re-sheathing, first closes and covers mouth opening 36 and then constrains within its interior embolic protection filter 29. In this manner, squeezing out of debris during re-sheathing of embolic protection filter 29 is prevented.

In order to avoid frictional contact between the surface of cover sheath 22 and the leaflets of aortic valve 13, cover sheath 22 is not shifted past aortic valve 13 but remains proximal to dilation balloon 19 and, thus, downstream of aortic valve 13.

According to the first embodiment, shifting section 26 is provided in between dilation balloon 19 and embolic protection filter 29, this way enabling distal to proximal re-sheathing of embolic protection filter 29 while at the same time avoiding frictional contact between cover sheath 22 and aortic valve 13.

As a consequence, shifting section 26 adds to distance a between the distal end of dilation balloon 19 and mouth opening 36 of embolic protection filter 29.

Hence, in order to ensure under all circumstances embolic protection of the carotids during valvuloplasty of aortic valve 13, catheter 10 is configured such that distance a, including shifting section 26, is short enough to protect side branches of the aorta but large enough to allow the sheath mechanism to work.

This distance is generally chosen at least slightly smaller than the distance between aortic valve 13 and the ostia of the carotid arteries. Hence, as soon as dilation balloon 19 is positioned in the residual opening of the aortic valve and embolic protection filter 29 is deployed, mouth opening 36 of embolic protection filter 29 assumes a position upstream of the carotid arteries. Therefore, during valvuloplasty of aortic valve 13, the passage of debris into the carotid arteries as well as into other parts of the vasculature is prevented.

Fig. 5 shows catheter 10 as in Fig. 4, but now with the dilation balloon 19 being inflated.

Dilation balloon 19 has been inflated thereby dilating aortic valve 13 and compressing its leaflets against the aortic walls.

Due to dilation, calcified material covering and stiffening the leaflets of aortic valve 13 is cracked open. Hence, optimally, the leaflets of the aortic valve 13 regain flexibility.

During this dilation process, calcified debris 37 is released from the leaflets of aortic valve 13 into the blood stream.

This debris 37, subsequently, is carried by periodic blood flow 35 in downstream direction through mouth opening 36 and becomes entrapped in embolic protection filter 29. Accordingly, particles of debris 37 are prevented from entering the downstream vasculature, for example the carotids, and from causing embolization there.

In order to retract catheter 10 from aorta 12, embolic protection filter 29 has to be compacted and filter section 21 again has to be covered at least partially by cover sheath 22.

Fig. 6 shows catheter 10 as in Fig. 5, but now with cover sheath 22 being shifted in proximal direction back into its initial position.

This shifting of cover sheath 22 into its initial position is achieved by the operator pulling actuating wires 24 and thus actuating element 23 in proximal direction.

During this process, cover sheath 22 is shifted in distal to proximal direction. Cover sheath 22 initially makes contact with self expandable elements 31, forcing them into a compressed conformation and hence closing mouth opening 36. Thus, mouth opening 36 of embolic protection filter 29 is closed off from the lumen of blood vessel 12, locking the interior of embolic protection filter 29 from the blood flow 35.

Only after mouth opening 36 is covered by cover sheath 22, the remaining part of embolic protection filter 29 is compressed into cover sheath 22.

This way, no squeezing out of debris 37 from embolic protection filter 29 can occur. Therefore, debris 37 remains safely contained within catheter 10 throughout and after re-sheathing and cannot cause downstream embolization.

It is, in this connection, of course possible to compress embolic protection filter 29 only partially, closing its mouth opening 36 but leaving it uncovered by cover sheath 22 proximal to mouth opening 36. In this configuration, which leaves more space for debris contained in embolic protection filter 29, catheter 10 may already be retracted from aorta 12. However, in order to better prevent damages of the vasculature, it is generally preferred to fully retract cover sheath 22 over embolic protection filter 29.

During closure of mouth opening 36, radiopaque markers 32 are shifted back into a common, central position. This way, the operator can, as already described above, observe the successful closure of mouth opening 36 of embolic protection filter 29 via x-ray.

The catheter 10 can now be safely retracted from aorta 12.

In an alternative to the method described in connection with Figs. 1 to 6, aortic valves 13 may also be treated and/or replaced in an antegrade manner, entering aortic valve 13 in downstream direction, coming from the left ventricle of the heart. In the latter case, a catheter 10' according to a second variant of the first embodiment of the present invention can be used, which embodiment is shown in Fig. 7.

A major difference between catheter 10' of Fig. 7 and catheter 10 of Figs. 1 to 6 is that, while catheter 10 has deployment section 18 provided on catheter body 15 distal to filter section 21, catheter 10' has deployment section 18 provided on a catheter body 15' proximal to filter section 21. Consequentially, also de-airing channel 33' has to be extended to that position.

During antegrade valvuloplasty of the aortic valve 13, catheter 10' according to this embodiment is inserted through the apex of the patient's heart (not shown) into the left ventricle. Then, catheter 10' is inserted through the leaflets of aortic valve 13 into aorta 12.

This step is generally critical in connection with the catheters of the prior art, because the large diameters of the known catheters, for example from WO 2006/031648 A2, lead to intense contact between the catheter surface and the leaflets of aortic valve 13. Hence, the danger of debris release from the aortic valve is relatively high even prior to the establishment of embolic protection.

Novel catheter 10' has a smaller diameter compared to catheters of the prior art. This smaller diameter relates to the fact that cover sheath 22 is adjusted for housing exclusively filter section 21 and not relatively bulky dilation balloon 19. Hence, using the novel catheter 10', the danger of debris release during catheter insertion through aortic valve 13 is reduced.

In the course of valvuloplasty, catheter 10' is further inserted through aortic valve 13 until dilation balloon 19 is positioned inside the residual opening of the aortic valve 13.

Also during insertion of dilation balloon 19 through aortic valve 13, the fact that cover sheath 22 does not cover dilation balloon 19, therefore not adding to its diameter, reduces the danger of debris release.

When dilation balloon 19 is in position, cover sheath 22 is proximally shifted in order to deploy embolic protection filter 29. This is achieved by the operator retracting actuating wires 24 in proximal direction. Actuating element 23 and cover sheath 22 are, hence, shifted in direction towards dilation balloon. At the end of this process, actuating element 23 and cover sheath 22 reside on shifting section 26.

Thus, cover sheath 22 is not retracted past aortic valve 13. Accordingly, by contrast to prior art catheters, no additional debris release is caused by retraction of cover sheath 22 when using catheter 10' according to the present invention.

During proximal shift of cover sheath 22, embolic protection filter 29 is deployed, thereby unfolding, triggered by the elastic expansion of self-expandable elements 31, against the aortic walls. Expansion of embolic protection filter 29 can be visualized via x-ray in a manner described hereinabove in connection with the embodiment of Figs. 1 to 6. After embolic protection is thus established, valvuloplasty is performed on aortic valve 13 using dilation balloon 19. Debris released during valvuloplasty is carried by periodic blood flow 35 into embolic protection filter 29.

After valvuloplasty is finished, the operator moves cover sheath 22 in distal direction by pushing distally actuating wires 24. Cover sheath 24, hence, constrains self- expandable elements 31, closing mouth opening 36 of embolic protection filter 29.

Optionally, cover sheath 22 may be advanced further in distal direction in order to cover and compress the entire embolic protection filter 29. In this case, it is of advantage, that mouth opening 36 is closed prior to compression of embolic protection filter 29, preventing the squeezing out of debris from embolic protection filter 29 during compression.

As described hereinabove, also closing of mouth opening 36 can be visualized via x- ray.

When closure of mouth opening or, respectively, the compression of the entire embolic protection filter 29 is finished, the catheter can be safely retracted from aortic valve 13 and removed through the left ventricle and apex of the patient's heart.

Hence, the novel catheter 10', during various steps prior to, during and after antegrade valvuloplasty, serves to reduce embolic risk.

Fig. 8 shows, in schematic side view, a catheter 10" according to a second embodiment of the present invention.

Catheter 10", instead of comprising the cover sheath 22 of the embodiments of Figs. 1 to 7, comprises a wire loop 38 located at and slidably connected to mouth opening 36 of an embolic protection filter 29". This wire loop 38, like cover sheath 22 (Figs. 1 to 7), serves to open and close mouth opening 36 and is connected to an actuating wire 24".

In the catheter's initial conformation, not shown in Fig. 8, actuating wire 24" as well as the larger portion of wire loop 38 are accommodated in an actuating lumen similar to actuating lumens 25 of Figs. 1 to 7 and connecting to the outside of the catheter through a lateral opening 39. A smaller portion of wire loop 38, engaging mouth opening 36, is located outside catheter body 14". Mouth opening 36, in this conformation, is narrowed by wire loop 38 and compressed against the surface of catheter body 14".

Catheter 10" is inserted into a patient's aortic valve 13 in an antegrade manner, passing the heart's apex and left ventricle (not shown).

During insertion of the catheter's filter section 21 through aortic valve 13, it is of particular advantage that catheter 10" does not comprise a cover sheath 22 (as shown in Fig. 1 to 7) and therefore has a particularly small diameter. Hence, the release of debris during this step is reduced compared to prior art catheters.

After dilation balloon 19 has been placed inside the residual opening of aortic valve 13, embolic protection filter 29" is allowed to expand. This is achieved by the operator pushing actuating wire 24 and thus wire loop 38 in distal direction. During this process, wire loop 38 gradually exits opening 39.

Hence, wire loop 38, which preferably is comprised of an elastic or shape-memory material such as Nitinol, is allowed to expand into a drop-like conformation, its pointed tip being attached to actuating wire 24. This state is shown in Fig. 8.

During its expansion, wire loop 38 unfolds embolic protection filter 29", pressing the borders of its mouth opening 36" against the aortic walls. Hence, embolic protection is established. Consequently, dilation balloon 19 is expanded for valvuloplasty of aortic valve 13. Debris released during this process is carried by periodic blood flow 35 into embolic protection filter 29".

After valvuloplasty is finished, embolic protection filter 29" has to be collapsed in order to allow the retraction of catheter 10" from the patient's heart.

In order to collapse embolic protection filter, actuating wire 24" is retracted by the operator in proximal direction, pulling the majority of wire loop 38 through opening 39 and into catheter body 14.

Wire loop 38 is slidably connected to mouth opening 36 in a draw-string like manner. Hence, mouth opening 36 narrows as wire loop 38 is gradually retracted through opening 39 and into catheter body 14". Finally, mouth opening 36 is, like in its initial conformation as described above, completely closed and compressed against catheter body 14". Only then, embolic protection filter 29" is compacted against catheter body 14" by stretching it in longitudinal direction. This is achieved by pulling wire loop 38 and, hence, mouth opening 36 further in proximal direction until the initial conformation of wire loop 38 is accomplished.

To summarize, the novel catheter serves to improve the efficiency and safety of debris containment during valvuloplasty. Further, the novel catheter has a reduced diameter compared to catheters of the prior art and reduces the friction between catheter surfaces and the leaflets of the aortic valve to be treated.

Hence, downstream embolization and its adverse effects on the patient's health can be at large prevented.

This is achieved in that the new catheter in all variants and embodiments shown does not has a sheath that covers the balloon. Further, the new catheters have a section between filter section 21, housing embolic protection filter 29, and deploy- ment section 18, housing dilation balloonl9, that serves for inflating and deflating/compacting embolic protection filter 29, without having any influence or effect on dilation balloon 19.

This section in between the two "active sections 18 and 21" serves to either receive the filter sheath 22, as used with catheters 10 and 10' of Figs. 1 to 7, or to allow the compacting of filter 29", as discussed in connection with Fig. 8.

Claims

1. Catheter for insertion and deployment of a dilation balloon (19) inside a blood vessel (12), the catheter (10, 10', 10") comprising a catheter body (14, 14', 14"'), a deployment section (18), provided on said catheter body (14, 14', 14"'), which deployment section (18) comprises said dilation balloon (19) and is adjusted for housing and deploying said dilation balloon (19), and a filter section (21), provided on said catheter body (14, 14', 14"'), which filter section (21) comprises an embolic protection filter (29) with a mouth opening (36), characterized in that between deployment section (18) and filter section (21) catheter body (14, 14', 14"') comprises means (26, 39) that allow inflation and deflation of embolic protection filter (29) without influencing dilation balloon (19).

2. Catheter according to claim 1, characterized in that said means (26,39) comprise a shifting section (26) for receiving a cover sheath (26) adjusted for exclusively housing and deploying said embolic protection filter (29).

3. Catheter according to claim 1, characterized in that said means (26,39) comprise an opening (39) receiving at least one actuation wire (24) connected to a wire loop (38) which in turn is connected to mouth opening (36).

4. Catheter according to claim 1 or claim 2, characterized in that said filter section (21) comprises a cover sheath (22) adjusted for exclusively housing and deploying said embolic protection filter (29), and that said cover sheath (22), for deploying said embolic protection filter (29), is shifted such that it first uncovers the embolic protection filter (29) and then the mouth opening (36) and, for re-sheathing said embolic protection filter (29), is shifted such that it first covers the mouth opening (36) and then at least a part of the embolic protection filter (29).

5. Catheter for retrograde insertion and deployment of a dilation balloon (19) inside a heart valve (13), the catheter (10) comprising a catheter body (14, 14'), a deployment section (18), provided near a distal end (16) of said catheter body (14, 14'), which deployment section (18) comprises said dilation balloon (19) and is adjusted for housing and deploying said dilation balloon (19), and a filter section (21), provided on said catheter body (14, 14') proximal to said deployment section (18), which filter section (21) comprises an embolic protection filter (29) with a distal mouth opening (36), characterized in that said filter section (21) comprises a cover sheath (22) adjusted for exclusively housing and deploying said embolic protection filter (29), said cover sheath (22), when housing said embolic protection filter (29), extends proximal of said deployment section (18), and that said cover sheath (22), for deploying said embolic protection filter (29), is shifted in distal direction, such that it first uncovers the embolic protection filter (29), and then the mouth opening (36) and, for re-sheathing said embolic protection filter (29), is shifted in proximal direction, such that it first covers the mouth opening (36) and then at least a part of the embolic protection filter (29).

6. Catheter for antegrade insertion and deployment of a dilation balloon (19) inside a heart valve (12), the catheter (10") comprising a catheter body (14"), a filter section (21), provided near a distal end (16) of said catheter body (14"), which filter section (21) comprises an embolic protection filter (29) with a proximal mouth opening, and a deployment section (18), provided on said catheter body (14") proximal to said filter section (21), which deployment section (18) comprises said dilation balloon (19) and is adjusted for housing and deploying said dilation balloon (19), characterized in that said filter section (21) comprises a cover sheath (22) adjusted for exclusively housing and deploying said embolic protection filter (28), said cover sheath (22), when housing said embolic protection filter (28), extends distal of said deployment section (18), and that said cover sheath (22), for deploying said embolic protection filter (28), is shifted in proximal direction, such that it first uncovers the embolic protection filter (28) and then the mouth opening, and, for re-sheathing said embolic protection filter (28), is shifted in distal direction, such that it first covers the mouth opening and then at least a part of the embolic protection filter (28).

7. Catheter according to anyone of claims 1 to 6, characterized in that the embolic protection filter (29) is self expandable and, upon deployment, radially contacts the walls of the blood vessel (12).

8. Catheter according to anyone of claims 1 to 7, characterized in that the embolic protection filter (29) comprises two or more radiopaque markers (32).

9. Catheter according to anyone of claims 1 to 8, characterized in that it comprises one or more actuating wires (24) connected to said cover sheath (22).

10. Catheter according to anyone of claims 1 to 9, characterized in that it comprises a channel (33) adjusted for de-airing.

11. Catheter according to anyone of claims 1 to 10, characterized in that the cover sheath (22) comprises secondary openings (34).

12. Catheter for insertion and deployment of a dilation balloon (19) inside a blood vessel (12), the catheter (10"') comprising a catheter body (14"'), a deployment section (18), provided on said catheter body (14"'), which deployment section (18) comprises said dilation balloon (19) and is adjusted for housing and deploying said dilation balloon (19), and a filter section (21), provided on said catheter body (14"'), which filter section (21) comprises an embolic protection filter (29) with a mouth opening (36), characterized in that said filter section (21) comprises a wire loop (38), provided at said mouth opening (36) of said embolic protection filter (29), and one or more actuating wires (24"'), connected at their distal ends to said wire loop (38), and that said wire loop (38) is configured such that it opens said mouth opening (36) when said one or more actuating wires (24"') are shifted in a first direction and that it closes said mouth opening (36) when said one or more actuating wires (24"') are shifted in a second direction, opposite to said first direction.