WO2008012839A1

WO2008012839A1 - Kit for performing subcommissuroplasty during aortic valve reconstruction

Info

Publication number: WO2008012839A1
Application number: PCT/IT2006/000560
Authority: WO
Inventors: Carlo Antona
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-07-24
Filing date: 2006-07-24
Publication date: 2008-01-31
Anticipated expiration: 2009-01-24

Abstract

The present invention relates to a kit comprising two retaining members (5, 6) adapted to be inserted in an aortic valve and a connection member (7) extending along a longitudinal axis (X-X), in which one of the ends of the connection member (7) is adapted to enable the sliding of one retaining member (5) from this end towards the opposite end. The kit further comprises members (10) adapted to secure the retaining member (5) with respect to the connection member (7). The present invention also relates a method for the reduction of the dilation of the aortic annulus using the kit in subject.

Description

Kit for performing subcommissuroplasty during aortic valve reconstruction

DESCRIPTION

The present invention relates to a kit and a method for performing subcommissuroplasty during aortic valve reconstruction.

Subcommissuroplasty is one of the surgical techniques used to repair the aortic valve when the valve flaps are normal and the insufficiency is caused by a dilation of the structure .

In Fig. 1, the aortic valve is formed by three valve leaflets or cusps 2, conventionally described as "swallow's nest", which are attached to the aorta 1. The apex of attachment of two leaflets is known as the commissure.

In Fig. 1, "v" indicates the left ventricle side, while "a" indicates the ascending aorta; the arrow F shows the normal direction of blood flow.

The attachment base of the leaflets 2 is shown by 3 and is composed of tissue intermediate between the tissue forming the leaflets 2 and the tissue forming the wall of the aorta 1. This tissue is in practice formed by both tissues so that its composition gradually thickens as it comes closer to the wall of the aorta or the wall of the leaflet, thus providing a homogeneous transition therebetween.

Following the line of attachment of two adjacent leaflets 2, it is possible to see an acute-angled isosceles triangle 4 whose apex A is in the commissure, whose sides B and C are formed by the attachment of each leaflet and whose "virtual" base D is disposed between the lower attachment points of each leaflet. The point of thickening of the collagen to which the valve leaflets 2 are attached is known, in the surgical literature, as the aortic annulus and is used as a synonym for "ventricular-arterial junction".

The dilation of the aortic annulus is the main cause of the insufficiency of the aortic valve and causes the leaflets 2 to move away from one another. One of the causes of this spacing is the dilation of the. subcommissural triangle 4 which may dilate to the extent that it takes the form of an equilateral triangle or, in more serious cases; even further. This dilation causes a reduction of the contact surface between the flaps of the leaflets (also known as the coaptation surface) and the appearance of an insufficiency in the aortic valve.

In order to return the subcommissural triangle 4 to a shape and dimensions enabling the coaptation of the leaflets 2 with one another, a subcommissuroplasty is carried out to reduce the amplitude of the subcommissural triangle 4 by positioning one or more suture stitches along the sides of the subcommissural triangle so as to bring the leaflets 2 closer to one another and return them to normal coaptation.

In current methods, the reconstruction system takes the form of a suture thread which is passed through twice and supported by two plates (called pledgets) which are disposed at the sides of the valve flaps and retained by the suture thread.

This method makes it necessary, however, for the surgeon to form knots with the suture thread for each side of the valve leaflet.

This operation, although not particularly complex, takes a certain time and, in any case, the knot formed by the suture thread occupies a non-negligible volume.

During normal operation of the cardiac valve, moreover, the knot could come into contact with the internal tissue of the aortic valve and damage it.

A further drawback of existing systems is that it is necessary to use a single thread for the suture which has comparable mechanical properties over its entire length.

It is not therefore possible to carry out a subcommissuroplasty during aortic valve reconstruction which merely returns the flaps of the leaflets to their original coaptation, as it is necessary to link them together substantially reducing the valve aperture. The properties of the suture thread also cancel out the natural elasticity of the tissue forming the triangle 4, by securing the bases 3, to which the two leaflets are attached, in contact with one another.

For these reasons, it is desirable to have a kit making it possible to carry out a subcommissuroplasty operation in a faster a^id more precise manner than has been possible up to now and which makes it possible to reduce the restrictions of the valve aperture to the absolute minimum, making it possible to retain the elasticity of the annulus. In view of the prior art described above, the object of the present invention is to provide a kit able at least partially to remedy the known drawbacks described above.

In accordance with the present invention, this object is achieved by means of a kit according to claim 1 and by a method according to claim 14. More detailed specific embodiments are set out in the dependent claims.

The characteristic features and advantages of the present invention are set out in the following detailed description of a practical embodiment thereof, given purely by way of non-limiting example, made with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a section of left ventricle, aortic annulus and ascending aorta shown in longitudinal and open section;

Fig. 2 is an exploded perspective view of a device according to an embodiment of the present invention; Fig. 3 is a perspective view, partly in section, of the device of Fig. 2, exploded and located at the attachment base of two valve leaflets;

Fig. 4 is a diagrammatic view, partly in section, of an intermediate step of application of the device of Fig. 2;

Fig. 5 is a diagrammatic view, partly in section, of a final step of application ofthe device of Fig. 2;

Fig. 6 is a diagrammatic view from the ascending aorta to the left ventricle, partly in section, of an aortic valve after the application ofthe device of Fig. 2;

Fig. 7 is an exploded perspective view of a device according to a further embodiment ofthe present invention. In Figs. 2 and 3, the device ofthe invention is formed by a kit comprising two retaining members 5, 6 and by connection members, preferably of elongate stick shape, extending substantially along a longitudinal axis X-X.

The connection members may for instance be formed by a single connection member 7 or, as shown in Fig. 7, by two separate connection members, which may differ from one another, for instance in terms of their length.

If two connection members 7a, 7b are used, the member closest to the vertex ofthe subcommissural triangle 4 will have to be shorter in length. It may therefore be envisaged to make one of the two connection members 7a, 7b shorter than the other so that it can be more readily disposed in its final position.

The retaining members 5, 6 are preferably in the form of substantially planar plates, as shown in Fig. 2, or in the form of substantially concave plates, as shown in Fig. 7. They extend substantially perpendicular to the axis X-X, at least in the vicinity of their intersection with this axis X-X.

If there are two connection members 7a, 7b, the plates may be connected (or connectable) thereto so that when the device is in use, they are disposed in a convergent configuration at an angle adapted appropriately to fit the shape of the tissue on which they are disposed.

The shape of the retaining members 5, 6 may be either substantially rectangular, as shown in the Figures, or substantially oval, so as to enable a better fit with the configuration of the anatomical site in which they are to be inserted; their shape and dimensions may be similar to those of the pledgets already in use in this type of operation.

Their preferred shape is substantially oval, with a smaller dimension of approximately 0.5-1 mm and a greater dimension of approximately 2-4 mm.

In the following description, reference will be made, for brevity, to the embodiment shown in Figs. 2 to 6, which comprises a single connection member 7. Unless specifically indicated otherwise, all the characteristic features described with reference to the single connection member 7 may be considered to relate to both connection members 7a, 7b in the embodiment (shown in Fig. 7) comprising two such members. The connection member 7 may comprise, at one free end at least, means 8 adapted to connect it to a suture thread (for instance a hole or a hook) so as to promote its insertion into the attachment base 3 of the leaflets 2 after they have been perforated by a suture needle.

The retaining member 5 which is not rigid with the connection member 7 is able to slide with respect to this connection member 7 from the free end to the opposite end. One of the retaining members 5, 6 may be rigid with the connection member 7.

If there are two connection members 7a, 7b, they may either be rigid with the same retaining member, as in Fig. 7, or may each be rigid with a different retaining member.

The two connection members 7a, 7b may advantageously be spaced from one another along the greater axis of each retaining member 5, 6.

The distance between them may advantageously be equal to approximately one third of the maximum dimension of the retaining members 5, 6. A third embodiment is possible as an alternative to these previous embodiments, in which both the retaining "fnembers 5, 6 are separate from the connection member 7 and are adapted to slide with respect thereto so that they can be moved closer together.

To summarise, the possible embodiments comprise two retaining members 5, 6 and one (7) or two (7a, 7b) connection members, each of which may be rigid with one or none of the retaining members 5, 6, for each possible combination.

The retaining members 5, 6 may be provided with one or more seats 11 in the form, for instance, of through holes, enabling them to cooperate with the connection member 7. If there is a single connection member 7, the seat 11 may advantageously be provided at the centre of the retaining member 5 in which the connection member 7 is to be inserted.

If there are two connection members 7a, 7b and both are rigid with one of the retaining members 5, 6, the seat 11 is provided in the other retaining member 6, 5 at the location of the free end of the connection member which is to be inserted therein. In this way, the retaining members 5, 6 may, for instance, each have a seat 11 and may both be rigid with one of the two connection members; in a second embodiment, one of the two retaining members 5 may be provided with two seats 11 and the other retaining member 6 may be rigid with both the connection members 7a, 7b (see Fig. 7 in this respect). The relative position of the retaining members 5, 6 may be secured by providing the connection member 7 with peripheral grooves 9 adapted to cooperate with appropriate clips 10 for endocardiac surgical operations.

As shown in Fig. 2, the connection member 7 may advantageously have, in the vicinity of the retaining member with whiph it is rigid, a section 12 on which no peripheral groove 9 is provided.

The length of the section 12 nevertheless has to be such as to enable the surgeon to leave the two attachment bases 3 of the valve leaflets 2 at a distance (see

Fig. 5) such as to return the subcommissural triangle 4 to the correct shape. In the case of Figs. 4 and 5, for instance, the length of the section 12 would also make it possible to leave a distance lower than that shown.

The kit may advantageously comprise a plurality of connection members 7 having different lengths of the sections 12 and/or different overall lengths so that the kit can be adapted to the actual needs of each patient. As shown in Fig. 5, one or a plurality of peripheral grooves 9 may advantageously comprise a score line, so that the portion 13 of the member 7 which is surplus to requirements after the kit has been successfully inserted in a patient may be removed. It will be appreciated that the score line must not create any risk of accidental detachment of the surplus portion 13. The score line is preferably formed so that the shape of the remaining portion is as biocompatible as possible, avoiding sharp edges for instance.

The connection member 7 may be provided with a section which may be longitudinally deformed or which has a lower longitudinal rigidity than the remaining sections. This greater deformability may be obtained by using, in this zone, a material having a higher coefficient of longitudinal deformation than that from which the other sections are formed.

As an alternative, this section of greater deformability may be formed from the same material, but with a geometry differing from the other sections. The longitudinal rigidity of this zone of greater deformability must be such as to enable the relative physiological movements of the attachment bases 3 of the leaflets 2, i.e. it must enable the leaflets 2 to move apart from one another during the systoles and help them to close up during the diastoles.

As an alternative to what is shown in the Figures, the single connection member 7 may be disposed in a decentralised position, for instance further from the subcommissural zone with respect to the centre of the retaining member 6. This "book" embodiment has the advantage that the deformability of the retaining members 5, 6 is obtained using the coefficient of flexural strength of the material of the connection member 7.

The profile of the connection member 7 has to be such that it does not create turbulence and causes the minimum disturbance to the blood flow; it may be, for instance, cylindrical. It will be appreciated that other more complex haemodynamic geometries could be chosen from among thosά known in the prior art.

All the members have to be made from biocompatible material, for instance polymer material, such as PTFE, HDPE, (poly)MMA, or metal material such as titanium; the retaining members may also be made from pyrolitic carbon or DLC (diamond-like carbon).

The operations to insert the device of the present invention during a subcommissuroplasty operation will be briefly described below.

Example 1 This example relates to a kit as shown in Figs. 2 to 6, in which there is a single connection member 7 provided integrally with one of the two retaining members 5.

After the surgeon has gained access to the aortic valve by known techniques, he decides which subcommissural triangle 4 (or which subcommissural triangles 4) need to have their aperture reduced and, therefore, the point (or points) into which the connection member 7 is to be inserted.

Following this preliminary assessment, he inserts the free end of a connection member 7 through the first and through the second base 3 of the two valve leaflets 2 adjacent to the first subcommissural triangle 4 whose aperture is to be reduced.

At this point, the surgeon inserts the second retaining member 5 about the connection member 7 and presses one against the other, thereby regulating the distance between the two attachment bases 3 of the leaflets 2 and thus the aperture of the subcommissural triangle 4.

Once this initial regulation has taken place, the surgeon uses a temporary clip 10 to keep the two retaining members 5, 6 secured together. He then carries out similar operations on any other subcommissural triangles

4 which need to be reduced.

At this point, the need to correct the distances between the retaining members 5, 6 of each kit is assessed: if these distances are correct, the temporary clips 10 are replaced by permanent clips 10; if not, the surgeon carries out one or more further trial regulations.

Where necessary, the surgeon removes the surplus parts of the connection members 7, as shown in Fig. 5, and then concludes the operation normally.

Example 2

This example relates to a device in which both the retaining members 5, 6 are separate from the connection member 7.

This example differs from the preceding example in that the surgeon has to secure both the retaining members 5, 6 to each of the sides of the attachment bases 3 of the leaflets 2. It is possible, therefore, to use a permanent clip 10 on one of the two sides of the collection member 7, while using & temporary clip on the other side. Example 3

This example relates to a device comprising two connection members both separate from the retaining members 5, 6.

It is similar to the preceding example in that the surgeon has to secure both the retaining members 5, 6 to both the ends of both connection members for each subcommissural triangle 4 whose amplitude needs to be reduced.

It differs from the preceding case in that the possibility of having two connection members for each pair of leaflets 2 enables the surgeon to carry out a fine adjustment of the aperture of the subcommissural triangle 4.

In general, the following method can be described for each triangle: the surgeon first inserts the upper connection member and then the lower connection member (or vice versa). He then secures one of the two retaining members 5 temporarily or permanently on one side by ^"appropriate clips 10; the second of the two retaining members 6 is temporarily secured to the other side. Once complete, this procedure is repeated for the other triangles 4 and the overall result is assessed.

The surgeon then adjusts, in a precise manner, for each triangle 4, the distance between the two retaining members 5, 6 at the location of both the upper connection member and the lower connection member (not necessarily in that order) and lastly replaces all the temporary clips with permanent clips.

He then removes the surplus portions 13 and completes the operation normally.

It will be appreciated that a person skilled in the art, in order to satisfy allied and specific requirements, could make many modifications and variations to the configurations described above, for instance using three or more connection members, providing a stabilisation member (for instance a ring) to stabilise the retaining members with one another or by- providing means adapted to prevent further dilation (after the surgery) of the aortic annulus. All such modifications nevertheless come within the scope of protection of the invention as set out in the accompanying claims.

Claims

1. A kit comprising a first (5) and a second (6) retaining member adapted to be inserted in an aortic valve when performing a subcommissuroplasty operation, and at least one connection member (7) extending along a longitudinal axis (X-X), the connection member (7) being adapted to enable the sliding, with respect to this connection member (7), of the first retaining member (5) in the direction of the longitudinal axis (X-X) towards the second retaining member (6) and being provided at one of its ends at least with members adapted to secure the first leaflet in the position reached when sliding is complete.

2. A kit according to claim 1, wherein at least one portion having a predetermined longitudinal extension of the connection member (7) has a longitudinal rigidity lower than that of the remaining part of the connection member

(7).

3. A kit according to the preceding claim, wherein the portion having a lower longitudinal rigidity is made from a material different from that of the remaining portions of the connection member (7).

4. A kit according to any one of claims 1 to 3, wherein the retaining members (5, 6) are plates extending substantially in planes transverse to the longitudinal axis (X-X).

5. A kit according to the preceding claim, wherein the planes transverse to the longitudinal axis (X-X) are substantially perpendicular therebetween.

6. A kit according to any one of the preceding claims, wherein at least one of the retaining members (5, 6) has a seat (11) adapted to receive the connection member (7) in a sliding manner.

7. A kit according to the preceding claim, wherein both the retaining members (5, 6) have a respective seat (11) and both the ends of this connection member (7) are adapted to be engaged in one of the respective seats (11).

8. A kit according to any one of claims 1 to 7, wherein the connection member (7) is formed rigidly with only one of the first (5) and second (6) retaining members.

9. A kit according to any one of. claims 1 to 8, wherein the connection member (7) connects the retaining members (5, 6) from a position offset with respect to the centre of these retaining members (5, 6).

10. A kit according to claim 9, wherein when the kit is in use, the pressure exerted on these retaining members (5, 6) is transformed into a torque adapted to dispose the planes in which the retaining members (5, 6) lie at an angle to one another.

11. A kit according to any one of claims 1 to 10, comprising two connection members.

12. A kit according to any one of claims 1 to 11, comprising temporary clips (10) for the reversible fastening of the retaining members (5, 6) with respect to the at least one connection member (7), and at least one permanent clip (10) for the permanent fastening of the retaining members (5, 6) with respect to the at least one connection member (7).

13. A kit according to any one of claims 1 to 12, wherein the retaining members (5, 6) and the connection member (7) are made from a biocompatible material.

14. A method for the reduction of the dilation of the aortic annulus comprising the step of reducing the distance between two sides of the subcommissural triangle (4) to a predetermined value which is not zero.

15. A method for the reduction of the dilation of the aortic annulus according to claim 14, wherein the predetermined value is close to the physiological value.

16. A method for the reduction of the dilation of the aortic annulus according to any one of claims 14 or 15, wherein:

(a) a kit according to any one of claims 1 to 12 is provided,

(b) a connection member (7) of this kit is inserted through the attachment bases (3) of the valve leaflets (2) adjacent to^vthe subcommissural triangle (4) whose aperture it is intended to be reduced.

17. A method for the reduction of the dilation of the aortic annulus according to any one of claims 14 to 16 further comprising the step of: (c) inserting the second retaining member (5) on the connection member

(V).

18. A method for the reduction of the dilation of the aortic annulus according to any one of claims 14 to 17, further comprising the step of: (d) temporarily securing the position of at least one of the two retaining members (5, 6) with respect to the at least one connection member (7).

19. A method for the reduction of the dilation of the aortic annulus according to any one of claims 17 or 18, comprising the steps of:

(e) permanently securing the position of both retaining members (5, 6) with respect to the at least one connection member (7).

20. A method for the reduction of the dilation of the aortic annulus according to any one of claims 18 or 19, wherein the step of securing the position of at least one of the retaining members (5, 6) with respect to the at least one connection member (7) is carried out using clips (10).

21. A method for the reduction of the dilation of the aortic annulus according to any one of the preceding claims, wherein step (c) takes place prior to step (d) and step (d) prior to step (e).