Device for replacing a cardiac valve by percutaneous route

ES 2 233 482 T3

DESCRIPTION

Device for the replacement of a heart valve percutaneously.

The present invention relates to a device for the percutaneous replacement of a heart valve.

Replacement of a defective heart valve is currently performed, in most cases, by opening the chest, placing the patient under cardiopulmonary bypass, temporarily stopping the heart, and opening the heart for valve removal and replacement.

These successive stages of the operation have the drawback of involving a relatively long hospitalization of the patient and of being complex and expensive.

To obviate this drawback, it has been considered to replace a heart valve with a minimally invasive route. International applications (TCP) No. WO 93/01768 and WO 97/28807, as well as US patents Nos. 5 814 097, 5 370 685 or 5 545 214, explain known minimally invasive techniques as well as the instruments for placing practice these techniques. Document US 5 924 424 describes a device according to the preamble of claim 1.

However, it is considered that the existing techniques are not perfectly satisfactory and are susceptible to improvement. In particular, these techniques have the drawback that they impose in all cases the placement of the patient in extracorporeal circulation and the temporary arrest of the heart; its execution is difficult; they do not allow precise control of the native valve cut-off diameter to subsequently calibrate the prosthetic valve; they carry risks of diffusion of fragments of the native valve, frequently calcified, into the body, which can lead to embolism and risks of perforation of the aortic or cardiac wall; they also induce risks of acute blood reflux at the time of native valve ablation.

The device according to the present invention has been conceived in order to alleviate the shortcomings of these techniques.

In particular, the invention aims to provide a device that gives total satisfaction with regard to the removal and replacement of the valve, allowing intervention without opening the thorax, cardiac arrest and / or opening of the heart and avoiding any diffusion in the circulatory system of excised valve fragments.

The terms "distal" and "proximal" used below to describe the invention are defined in relation to the direction of blood circulation.

The device according to the invention comprises:

• An elongated support element;

• A first series of elongated sheets, arranged around the circumference of said elongated element; these blades are pivotally attached to the elongated element at their proximal longitudinal ends and each have a cutting edge at their distal longitudinal end; these blades can pivot with respect to the elongated element between a retracted position, in which they are close to the elongated element so as not to oppose an obstacle to the introduction and the sliding of the device within the body conduit in which the valve is located, especially in the aorta, and a deployed position in which these blades unfold in the form of a corolla so that their cutting edges are located one in the extension of the other, thus constituting a circular cutting edge.

• A second series of blades, arranged consecutively to said first series of blades in the distal direction; The blades of this second series of blades have an identical structure to that of the first mentioned series of blades, except that the blades of this second series are attached to the elongated element at their distal longitudinal ends and each one of them has a cutting edge at level of its proximal distal end;

• Means that allow the blades of said first and second series of blades to be brought from their folded position to their deployed position;

• Means that allow said series of blades to be axially displaced, one in the direction of the other between a position of mutual distance of these series of blades, in which a series of blades can be axially positioned on one of the sides of the native valve in so much so that the other series of blades is axially positioned on the other side of this valve, and an approaching position, in which the circular cutting edges are brought into contact with each other to thereby section the native valve so that it is separated from said body conduit; and • Means for percutaneously locating the axial position of the device in relation to the native valve that allow positioning each of the two aforementioned series of blades on each side of the valve.

The device according to the invention can be percutaneously introduced into said body conduit and slid within said conduit until each of the aforementioned series of blades is positioned on each side of the valve. This position is located by means of said locating means.

Use can be made of a peripheral perfusion or extracorporeal circulation system to facilitate the emptying of the blood in order to prevent stagnation of blood within the heart.

After the aforesaid positioning of the device, the leaflets of the two series of leaflets are deployed, then these two series are moved towards each other until the valve is sectioned. The conformation of these sheets allows this sectioning to be carried out in a single operation, thus without generating fragments capable of diffusing into the circulatory system or at least generating very few fragments; This conformation also allows a precise control of the diameter according to which the native valve is divided,

ES 2 233 482 T3 with a view to the subsequent calibration of the prosthetic valve.

The blades then return to their retracted position.

The prosthetic valve is then put in place.

This valve may be separate from the device, in which case the latter is removed and then the prosthetic valve is inserted and placed in position within said body conduit by means of a different device. However, the device according to the invention preferably comprises a proximal prosthetic valve with a radially deployable structure; This prosthetic valve can occupy a folded position, in which it is close to the wall of said elongated element and does not represent an obstacle for the introduction and sliding of the device inside said body conduit, and a deployed position, in the which rests against the wall of said conduit and is in a position to replace the native heart valve.

The device thus makes it possible to introduce and position the prosthetic valve in the appropriate place within the body conduit in the same action that allows the native valve to be divided. After resection of the latter, the device is axially slid in a distal direction in order to bring the prosthetic valve to the proper level within the conduit, after which the prosthetic valve is deployed. The device is then removed and the native valve recovered.

This elongated support element is preferably a tubular catheter.

This catheter thus allows blood to circulate through it during removal of the native valve.

The section of the conduit of this catheter must be sufficient to allow the circulation of blood through this conduit, which limits or avoids the recourse to putting the patient under extracorporeal circulation. The catheter can also have a reduced diameter, which facilitates the introduction and the sliding of the device within the body conduit, but then it is necessary to ensure the peripheral circulation by an external assistance system, such as an extracorporeal circulation system.

The catheter includes a lateral distal opening to allow blood to reach the body conduit, for example the ascending aorta, this opening being arranged so that the length of catheter traversed by the blood is as short as possible.

The device preferably includes a small distal inflatable balloon, placed at the level of the outer face of said elongated element; This small balloon has a shape that allows it to occupy a retracted position, in which it has a section such that it does not obstruct the introduction or sliding of the device within said body conduit, and a deployment position in which it occupies the entirety of the space existing between the outer face of said elongated element and the wall of said body duct and is supported, by means of a peripheral edge that it includes, against this wall.

The small balloon is inflated after positioning the series of leaflets on either side of the native valve, to prevent backflow of blood during ablation of the native valve. When said elongated element is a catheter, the small balloon also makes it possible to direct this blood so that it circulates only inside the catheter.

Once the prosthetic valve is in place, the small balloon is returned to its retracted position so that blood flow through the body passage is restored.

The device preferably includes a distal filter of soft material, placed at the level of the outer face of said elongated element; This filter has a shape that allows it to occupy a folding position, in which it has a section such that it does not obstruct the introduction or sliding of the device within said body duct, and a deployment position in which it occupies the entire space existing between the outer face of said elongated element and the wall of said body duct and is supported, by means of a peripheral edge that it includes, against this wall.

This filter makes it possible to capture the eventual fragments generated by the removal of the valve and retain them so that they are removed from the blood circulation.

The device may include means that allow said series of sheets to be displaced in an axial direction independently of said small balloon and / or of the filter. Once deployed, the latter (s) must not move axially in the body duct during the aforementioned axial displacement of the series of blades.

Said small balloon and / or said filter can also be detached from the device since they are mounted on an elongated element of their own.

In the case of intervention in a mitral valve, this small balloon and / or this filter are introduced into the aorta via the peripheral arterial route and as for the device, it is introduced into the heart through the peripheral venous system, up to the right atrium and then in the left atrium through the interatrial septum to the level of the mitral valve.

The prosthetic valve can advantageously include a frame made of shape memory material, especially of a nickel-titanium alloy known under the name "NITINOL".

This same valve can include valves of biological materials (preserved animal or human valves), or valves of synthetic materials, such as polymers.

For your good understanding, the invention is described again below with reference to the attached schematic drawing which represents, by way of non-limiting example, a preferred embodiment of the element in question.

Figure 1 is a longitudinal section view according to a first embodiment, intended for the treatment of an aortic valve;

Figure 2 is a cross-sectional view according to line II-II of Figure 1;

Figure 3 is a view similar to that of Figure 2, in another position of the subassembly comprising;

Figure 4 is a perspective view of a prosthetic valve that the device allows to put in place;

Figures 5 to 9 are views when it is positioned inside the heart, at the level of the valve to be treated, in the course of successive operations by which this valve is sectioned and the prosthetic valve shown in the figure is placed in place. figure 4; Figure 10 is a view of the prosthetic valve shown

ES 2 233 482 T3 in figure 4, after placing it in place, and figure 11 is a view of the device, according to another embodiment, intended for the treatment of a mitral valve.

Figures 1 to 3 represent a device 1 for replacing a percutaneous heart valve.

This device comprises a tubular catheter 2 formed by three tubes, 5, 6 and 7, fitted one inside the other, on which they are placed, from the proximal side to the distal side (considered with respect to blood circulation, that is, from the right to the left of figure 1), a prosthetic valve 10, two series of leaflets 11, 12, a small balloon 13 and a filter 14.

The three tubes 5, 6 and 7 are mounted so that they can slide one inside the other. The inner tube 5 delimits a conduit 15 whose section is sufficient to allow the circulation of blood through it.

On the proximal side, the intermediate tube 6 forms a tulip 6a that delimits, together with the inner tube 5, an annular cavity 17 in which the prosthetic valve 10 is contained in a retracted state.

Figure 4 shows that this valve 10 comprises a frame 20 and valves 21 functionally movably mounted on this frame 20.

The framework is made up of a set of wires 22, 23, 24 in materials that have shape memory, especially a nickel-titanium alloy known under the name "NITINOL", namely:

• A thread 22 at the proximal end which has, in the deployed situation of the valve 10, a substantially circular shape;

• A wire 23 at the distal end that forms three undulations in the axial direction, with these undulations evenly distributed over the circumference of valve 10, ^Y • An intermediate wire 24 that forms longitudinal undulations between wires 22 and 23, this wire 24 being attached to the latter two at the ends of each of these undulations.

The valves 21 are themselves made of biological material (preserved animal or human valves) or of synthetic material, such as a polymer.

The frame 20 can, when its material is cooled, contract radially in such a way that the valve 10 can enter the cavity 17. When this material is reheated to the temperature of the body, this frame 20 recovers its original shape, represented in the Figure 4, in which it has a diameter adapted to that of the body conduit, in particular the aorta, in which the native valve to be treated is located. This diameter of the frame 20 is such that the valve 10 bears against the wall of the body conduit and is immobilized in an axial direction with respect to it.

Each series of sheets 11, 12 comprises elongated metal sheets 30 and a small inflatable balloon 31 located between the catheter 2 and these sheets 30.

The blades 30 have a curved profile and are arranged on the circumference of the catheter 2.

The blades 30 of the proximal series 11 are pivotally attached to the tube 6 at their proximal ends and include a distal cutting edge 30a, while the blades 30 of the distal series 12 are pivotally attached to the outer tube 7 at their distal ends and include a proximal cutting edge 30b.

The joining of the sheets 30 to the tubes 6 and 7 respectively is carried out by welding the ends of the sheets 30 together, so that they form a ring; this ring is axially fixed to the corresponding tube 6,7 by crimping this ring on this tube 6, 7; the pivoting of the blades 30 is carried out by simple elastic deformation of said blades 30.

This pivoting is possible between a position of retraction of the blades 30, radially internal in relation to the catheter 2, which is shown in Figures 1 and

2, and a deployment position of these sheets 30 radially external with respect to this catheter 2, which is shown in figure 3. In the retracted position, the blades 30 are close to the wall of the tube 6 and partially overlap one another in such a way that they do not impede the introduction and the sliding of the device 1 inside the body duct in which they are placed. find the native valve to be treated; In the aforementioned deployed position, the blades 30 are deployed in the form of a corolla in such a way that their cutting edges 30a, 30b are placed one in extension of the other, thus constituting a circular cutting edge, visible in the figure

3.

Each small balloon 31, placed between the tube 6 and the sheets 30, can be inflated from the end of the catheter 2 that exits the patient, through a conduit 32 arranged in the tube 6. It also allows, when inflated, to carry the blades 30 from their retracted position to their deployed position, and vice versa when deflated.

The axial sliding of the tube 6 with respect to the tube 7 makes it possible to axially displace the series of sheets 11,12 one in the direction of the other, between positions of mutual distance, shown in figure 1, and of mutual approach. In the first of these positions, a series of blades 11 can be positioned axially on one side of the native valve while the other series of blades 12 is axially positioned on the other side of this valve, while in the second of these positions, the circular cutting edges of these two series of blades 11, 12 are mutually contacted and thus sever the native valve so as to separate it from said body conduit.

Tubes 5 to 7 also include barium sulfate references (not visible in the figures) that allow percutaneous monitoring of the axial position of device 1 in relation to the native valve, so that each of the series leaflets 11, 12 can be placed on each axial side of this valve.

These tubes 5 to 7 also include lateral distal openings (not shown) to allow blood to return to the body conduit; these openings are arranged so that the length of catheter 2 traversed by the blood is as short as possible, that is to say immediately after, in the distal direction, the filter 14.

The small balloon 13 is placed on the outer face of the tube 7, distally with respect to the series 12. This small balloon 13 has an annular shape and has been shaped to be able to occupy a folded position in which it has a section such that it does not su4

ES 2 233 482 T3 hinder the introduction and sliding of the device 1 within said body duct and a deployed position in which it occupies the entire space between the outer face of the tube 7 and the wall of said body duct and is it rests, by means of a peripheral edge 13a that it contains, against this wall.

The filter 14 is positioned distally with respect to the small balloon 13, on the tube 7, to which it is fixed axially. This filter 14 is made of soft material, for example made of polyester mesh and is shaped to be able to occupy a folded position in which it has a section such that it does not pose an obstacle to the introduction and sliding of the device 1 within said body duct and a deployed position in which it occupies the entire space between the outer face of catheter 2 and the wall of said body duct and is supported, by means of a peripheral edge 14a containing, against this wall.

A small inflatable balloon 35 is positioned between the tube 7 and the filter 14 so that, depending on whether it is inflated or deflated, it places the filter 14 in its respective deployed or retracted positions.

In practice, as shown in Figures 5 to 9, device 1 is introduced percutaneously into said body conduit 50 and is made to slide inside this conduit 50 until each of the series 11, 12 of blades is placed on each side of the native valve 55 to be treated (figure 5). This position is indicated by means of the aforementioned references.

In this position of the device, the proximal part of the catheter 2 is located within the heart, preferably in the left ventricle, while the aforementioned lateral distal openings are located in a peripheral arterial vessel, preferably in the ascending aorta.

Small balloons 13 and 35 are inflated in such a way as to force blood to flow only through conduit 15 and prevent backflow of blood during ablation of valve 55. A peripheral perfusion system is activated to facilitate this emptied.

Then the sheets 30 of the two series 11, 12 (figure 6) are deployed by inflating the small balloons 31, then these two series 11, 12 are brought closer to each other, by sliding the tube 6 with respect to the tube 7, until the valve is cut. 55 (figure 7).

The blades 30 then return to their folded position, deflating the small balloons 31, although they remain in their approaching position, which allows the sectioned valve 55 to be held between them.

Device 1 is then axially slid in the distal direction in order to bring tulip 6a to the proper level within conduit 50 (Figure 8), after which valve 10 is deployed by sliding tube 6 relative to tube 5 ( figure 9).

Small balloons 13 and 35 are deflated and then device 1 is removed and the valve is retrieved (Figure 10).

Figure 11 shows a second way of making the device 1, which allows an intervention on the mitral valve 56.

The same reference numbers are used to designate the same elements or parts that have already been mentioned, since these elements or parts are identical or similar between the two embodiments.

In this case, the tubular catheter is replaced by a support wire 2 on which one of the series of sheets is mounted and by a coupled tube that can slide over this wire and on which the second series of sheets is mounted; the inflation ducts of the small balloons 31 are routed along this support wire and the tube; the small balloon 13 and the filter 14 are separated from the device 1 and inserted into the aorta via the peripheral arterial route by means of a support wire 40, along which the inflation ducts of the small balloons 13 and 35 run. Device 1, devoid of the small balloon 13 and filter 14, is introduced into the heart through the peripheral venous system to the right atrium and from there to the left atrium through the interatrial septum to the level of valve 56.

As for the rest, device 1 works in the same way mentioned above.

The invention thus provides a device for replacing a heart valve percutaneously, making it possible to solve the drawbacks of the prior techniques. Indeed, the device 1 gives complete satisfaction with regard to the removal of the valve 55, 56, allowing intervention without cardiac arrest and avoiding, thanks to the filter 14, any diffusion into the circulatory system of fragments of the valve 55, 56.

It goes without saying that the invention is not limited to the embodiment described above by way of example but, on the contrary, encompasses all variant embodiments within the framework of the claims that follow. Thus, the device can include a fourth tube, fitted and being able to slide over tube 7, and this fourth tube includes the small balloon and the filter mounted on it and allowing said series of sheets to be displaced in an axial direction independently of this small balloon and / or or from this filter; The blades can be rectilinear as they are represented in the drawing or they can be curved towards the axis of the device at the level of its end that includes the cutting edge, so as to eliminate any risk of injury to the wall of the body duct, such as shows figure 12; the filter 14 can be of the self-expanding type and kept in its folded position by means of a sliding tube that covers it, rendering the small balloon 35 useless.