EP0713376A1

EP0713376A1 - Implantable heart valve

Info

Publication number: EP0713376A1
Application number: EP94924911A
Authority: EP
Inventors: Jean-Paul Couetil
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-08-13
Filing date: 1994-08-12
Publication date: 1996-05-29
Also published as: FR2708847A1; BR9407256A; AU7501994A; WO1995005133A1; JPH09501341A; CN1131384A; FR2708847B1; CA2169454A1

Abstract

Mitral-type implantable heart valve comprising an atrioventricular joining member (1) defining a channel (2)(F) for the blood flow, capable of being sealed by one or more movable membranes (3) fastened to an array of retaining threads (4), the valve being characterized in that said joining member includes a loop (1) which is engaged by the peripheral edge of said membrane (3) upon closure, and a hoop element (5) for anchoring said thread-array (4), provided on the front side of the loops in relation to the anatomical position of the heart in a plane angularly displaced by an angle α from the plane of said loop, wherein the hoop ends are integral with said loop (1).

Description

IMPLANTABLE HEART VALVE

The present invention relates to an implantable heart valve of the mitral type.

WO 91/19465 (FRATER) discloses mitral heart valves comprising in particular an atrioventricular junction element defining an opening for the blood flow which can be closed by at least one and, preferably, four mobile membranes attached to a network of retaining wires.

The junction element is annular and rigid while the retaining wires are sutured on the wall of the myocardium.

This structure poses numerous technical problems linked to the adjustment of the length of the retaining wires and to the rigidity of the junction element.

Indeed, the myocardium remains flaccid at the time of the intervention and, therefore, it is not possible to precisely determine the length of wire necessary to obtain proper functioning of the valve.

Under these conditions, it proves difficult to bring together in a reproducible manner the optimum conditions for fitting such a valve. In addition, the four membranes define, at full opening, a narrowed channel producing resistance to blood flow from the atrium to the left ventricle, which leads to functional disorders.

In addition, in certain cases, the network of retaining wires is the site of calcification phenomena which make said wires brittle and thus compromise the reliability of the valve.

The present invention aims to solve these technical problems satisfactorily.

This object is achieved by means of an implantable heart valve of the mitral type comprising an atrioventricular junction element defining a passage for the blood flow capable of being blocked by at least one mobile membrane, characterized in that said junction element comprises loop on which the peripheral edge of said membrane comes into bearing contact during closure and an anchoring arch connected to said membrane and disposed on the anterior side of the loop with reference to the anatomical position of the heart. According to an advantageous characteristic, said loop comprises lateral cheeks intended to separate the surrounding cardiac walls to allow the free movement of the membrane, said cheeks possibly being provided with stops limiting the angular displacement of the membrane.

According to a first embodiment, said hoop is movable and comprises means allowing its direct fixing on the free peripheral edge of said movable membrane and ensures, when the valve is closed, a sealed contact with said loop. Said means of fixing the movable arch on the peripheral edge of the membrane consist for example of a longitudinal slot formed in said arch, in which is engaged the peripheral edge of the membrane and whose internal lateral edges facing are provided respectively of a rib and a groove intended to be locked by snap-fastening of one into the other by pinching said membrane.

In fact, in most cases, it is not necessary to retain the mobile membrane because its intra-ventricular movement away from the loop is naturally limited by the atrioventricular flow and the intraventricular convective flows. Optionally, additional stops positioned appropriately will guarantee a determined amplitude of movement.

The arch also makes it possible to stiffen the free peripheral edge of the movable membrane and to tension it by preventing any winding or folding on itself. In addition, the membrane can be cut directly along the arch, which then serves as a guide and protection against possible drawing errors.

According to a second embodiment, said arch is fixed and located in a plane angularly offset by a certain angle from the plane of said loop while said movable membrane is connected by a network of retaining wires to said arch. The length of the retaining wires is such that, at the end of the travel, the membrane is in abutment against the front face of the loop during closing. In this case, the arch comprises through orifices for the passage of the retaining wires and notches at the outlet of said orifices. Preferably, the inclination of the arch and the length of the retaining wires are then determined so that, at full opening, the membrane makes an angle between 40 ^* and 90 ^* with the posterior face or the posterior edge. of the loop. In addition, ! s ends of the arch are secured to the outer edges of the loop.

According to a specific characteristic, the arch has a determined anteroposterior flexibility. In the embodiment with the fixed arch and the network of wires, this flexibility provides the retaining wires with elasticity when the membrane comes into contact with the loop during closing. The elastic tension thus created on the retaining wires in the ventricular systole phase favors the opening of the membrane during diastole with an anticipated diastolic opening, thereby further promoting the protodiastolic transmitral flow.

The valve of the invention makes it possible to overcome the patient's cardiac morphology because the retaining wires are no longer anchored on the ventricular wall but on the arch itself secured to the loop constituting the junction element. atrioventricular.

According to another advantageous characteristic, the rear face of the loop has a width less than or equal to that of the front face.

According to yet another characteristic, the radius of curvature of the loop is less than or equal to that of the fixed arch and substantially equal to that of the movable arch.

According to other characteristics, the width of the front face of the loop is variable around its periphery with a maximum in the middle part.

Likewise, the thickness of the loop is continuously variable around its periphery with a maximum in its middle part, thus defining between the posterior and anterior sides an angle of between 5 'and 20'.

According to a first alternative embodiment, said loop is closed and follows the contours of the natural mitral ring.

According to another alternative embodiment, said loop is open.

According to yet another variant, the loop is at least partially provided with a sheath of biocompatible material which ensures in contact with the membrane a sealed closure of said passage. It is also expected that the loop is elastically deformable in torsion.

Preferably, the fixed arch has a substantially circular section whose internal diameter is less than the width of the front face of the loop.

In the case of a movable bar, its section is adapted to the front face of the loop to optimize the tightness of the contact.

According to an alternative embodiment, the cross section of said loop is polygonal or triangular. According to other embodiments, the front face of the loop has a convex and / or concave curvature.

Preferably, said membrane is obtained by autografting a part of the pericardium but it can also be made of any other biocompatible, flexible or rigid material. The loop joining element is sutured with the natural ring and can be made in open loop.

Likewise, the pericardium can be used to form at least partially the sheath of the looping junction element by being sutured in addition to the natural ring of the patient. Under these conditions, the valve has only one movable membrane, which avoids any disturbance of the blood flow.

The invention will be better understood on reading the description which follows, accompanied by the drawings in which: - Figure 1 shows a perspective view of a first embodiment of the mitral valve of the invention;

- Figure 2 shows a perspective view of a second embodiment of the valve of the invention;

- Figure 3 shows a perspective view of a third embodiment of the invention;

- Figure 4 is a sectional view along a median plane of the valve of Figure 2;

- Figure 5a shows a sectional view of a first embodiment of the junction element of the valve; - Figure 5b shows a sectional view of a second embodiment of the valve connecting element; - Figure 6 shows a schematic view of the implantation of the valve of the invention.

The valve shown in perspective in FIGS. 1, 2 and 3 is intended to be placed in the mitral position, at the atrioventricular junction between the atrium O and the ventricle V of a patient, thus defining in the direction of the blood flow. F from upstream to downstream with reference to the anatomical position of the heart respectively an atrium or posterior side P and a ventricle or anterior side A.

The mitral valve of the invention comprises an atrioventricular junction element in the form of a loop 1 open (Figures 1 and 2) or closed (Figure 3), forming the seat of the valve and defining a passage

2 for communication for the blood flow F between the posterior face P and the anterior face A.

The closed loop atrioventricular junction element adapts to the contours with a substantially D profile of the natural mitral ring.

The passage 2 at the center of the open or closed loop 1 is capable of being closed by at least one mobile membrane 3 forming a valve with a curvilinear free edge. The movable diaphragm 3 is shown in the open position

(solid line) and in the closed position (dotted lines).

The membrane 3 is preferably formed by autograft from a portion of pericardium or else produced independently with a flexible biocompatible material such as PTFE or rigid (titanium, etc.).

When the atrioventricular junction element is an open loop, the membrane 3 is connected either to the free ends of the loop 1 and to the adjacent part of the patient's natural ring or to a band for fixing said loop to the patient's natural ring. When the loop is a closed loop, the movable membrane 3 is connected by its insertion edge 3a to the natural ring of the patient and to the adjacent part 1a of the closed loop (FIG. 3).

The natural ring is partly formed by the aorto-mitral veil and the membrane, inserted on the latter, is located immediately under the aortic valve K. 4/01004

The membrane 3 moves under the action of the blood flow F from a closed position where it is in contact by its periphery with the front face 12 of the loop 1 towards an open position where it frees the passage 2 (Figures 1 , 2 and 3). Conversely, the membrane 3 closes under the action of the left intraventricular flows F 'of convection, oriented from the ventricle V (side A) to the atrium O (side P), during the diastolic filling of the ventricle V whose frequency and l intensity naturally limit the opening of the membrane (see Figure 6). The membrane 3 is connected to an anchoring arch 5 which is disposed on the anterior side A of the loop 1 with reference to the anatomical position of the heart.

In the embodiment shown in Figure 1, the loop 1 is open and has lateral cheeks 13 intended to spread the surrounding cardiac walls to allow the free movement of the membrane 3. The cheeks 13 thus prevent the protrusion of the myocardial muscle which could hinder the movement of the membrane 3. The cheeks 13 are possibly provided on their internal face with stops

14 intended to guarantee a determined angular amplitude of movement of the membrane 3 relative to the plane passing through the front face 12 of the loop 1. The position of the stops 14 will determine the amplitude of the displacement of the membrane 3 with the arch 5 and therefore the optimal opening angle of the valve independently of the action of intraventricular F flows. The movable membrane 3 can, if necessary, be attached to the loop 1, for example by suturing, through orifices

15 formed on the ends of said loop. The anchoring arch 5 is fixed directly to all or part of the free peripheral edge of the movable membrane 3. The arch 5 is made with a rigid (metal, etc.) or semi-rigid (Delrin, polyethylene, etc.) material. .), biocompatible allowing to stiffen the periphery of the membrane 3.

When the valve closes, the arch 5 comes into contact with the front face 12 of the loop 1. The section of the movable arch 5 is adapted to the profile of the front face 12 of the loop 1 to optimize the contact tightness. The radius of curvature and the width of the loop 1 are determined as a function of the radius of curvature of the movable arch 5 so as to obtain a sufficient tight contact surface. Preferably, the radius of curvature of the loop 1 is substantially equal to that of the movable arch 5.

The method of fixing the arch 5 to the membrane 3 can be done by suturing, stapling, etc. One embodiment (not shown) consists in making said arch with a longitudinal slot in which is engaged the peripheral edge of the membrane; the internal lateral edges opposite said slot are then provided respectively with a rib and a groove intended to be locked by snapping one into the other by pinching said membrane. An alternative embodiment consists in making the arch in two parts respectively comprising complementary latching means. In this case, the peripheral edge of the membrane is sandwiched between the two parts of the split arch. Of course, it is also possible to stiffen more or less the periphery of the movable membrane in the vicinity by making it with a material whose rigidity is locally variable on its surface either by modification of its density, or by modification of its thickness.

It is expected that the thickness of the loop 1 is continuously variable around its periphery with a maximum in its middle part (see in particular Figure 4) thus defining between the rear 11 and front 12 an angle β between 5 ' and 20 '(corner minutes).

Furthermore, the loop is made with a polygonal section and the width of the front face 12 is continuously variable around its periphery with a maximum width in its middle part while the width of the rear face 11 of the loop 1 is less. or equal to that of the anterior face 12 and is reduced to the maximum in its middle part. It is even provided in a particular embodiment to make the loop 1 with a triangular section so that the front face 11 is pointed (see Figure 5b). Of course, these characteristics of the loop 1 can also apply to the other embodiments illustrated in FIGS. 2 and 3 and described below.

This configuration makes it possible to obtain a wider bearing surface for the posterior peripheral zone of the membrane 3 in the closed position and therefore to improve the tightness of the valve. / 01004

8

In the embodiment shown in FIG. 2, the membrane 3 is attached by a network of retaining wires 4 to the fixed anchoring hoop 5 which is disposed on the anterior side A of the loop 1, in an offset fixed plane angularly at an angle α from the plane passing through the front face 12 of the loop 1. The arch 5 is rigid and its free ends are integral with the open loop 1 preferably at the external edges of the free ends 10.

The angular sector of displacement of the movable membrane 3 is defined by the length of the retaining wires 4. The arch 5 is located in the plane passing through the free ends 10 of the loop 1 and containing the bisector of the angular sector of displacement of the membrane 3. The arch 5 is flexible in the anteroposterior plane. The angle α and the length of the wires 4 are determined so that, at full opening, the membrane 3 makes an angle γ between 40 ^* and 90 * with the flat rear face 11 or the rear edge of the loop 1 .

In the closed position, the membrane 3 is at the end of its travel and in contact with support against the front face 12 of the loop 1.

Under these conditions, the angle α is equal to (γ - β) / 2 because the arch is necessarily halfway between the open position and the closed position.

In order to allow the passage of the membrane 3 inside the fixed arch, the radius of curvature of the loop 1 is less than or equal to that of the arch 5. The arch 5 has a circular section whose internal diameter is much less than the width of the front face 12 of the loop 1 and is preferably of the order of a millimeter.

The retaining wires 4 are fixed to the hoop 5 either by passing through through orifices 50 opening out by retaining notches 50a, or by simple retention in said notches.

In the embodiment of FIG. 5 a, the loop 1 has an anterior face 12 of convex curvature, but it is also possible to conceive of embodiments where this curvature is totally or partially concave. In the embodiment of FIG. 5b, the section of the loop 1 is in a triangle, in particular in its middle part, but it is possible to also design an anterior face inclined at the level of the middle part (see figure 4).

The loop 1 is at least partially provided with a sheath 6 made of bio-compatible material which ensures, in bearing contact with the membrane 3, a tight closure of the passage 2.

The sheath 6 can be produced using a portion of the pericardium or any other flexible biocompatible material. Under these conditions, the sheath 6 is sutured to the patient's natural ring, leaving a narrow band 7 for fixing the pericardium or biocompatible material between the sheathed loop and the suture to the ring. In this way, the freedom of elastic deformation in torsion, elongation and / or compression of the fixation between the loop 1 and the patient's natural mitral ring is increased during the cardiac cycle.

Claims

CLAIMS 1. Mitral type implantable heart valve comprising an atrioventricular junction element (1) defining a passage (2) for the blood flow (F) capable of being closed by at least one mobile membrane (3), characterized in that said joining element comprises a loop (1) on which the peripheral edge of said membrane (3) comes into bearing contact during closing and an anchoring arch (5) connected to said membrane and disposed on the anterior side ( A) of the loop with reference to the anatomical position of the heart.

2. Valve according to claim 1, characterized in that said loop (1) comprises lateral cheeks (13) intended to separate the surrounding cardiac walls to allow the free movement of the membrane (3), said cheeks (13) possibly being provided with stops (14) limiting the angular displacement of the membrane (3).

3. Valve according to claim 1 or 2, characterized in that said hoop (5) is movable and comprises means allowing its direct fixing on the free peripheral edge of said movable membrane (3) and ensures, when the valve, a tight contact with said loop (1).

4. Valve according to claim 3, characterized in that said means for fixing the movable arch (5) on the peripheral edge of the membrane (3) consist of a longitudinal slot formed in said arch, in which is engaged the peripheral edge of the membrane and the opposite internal lateral edges of which are respectively provided with a rib and a groove intended to be locked by snapping one into the other by pinching said membrane.

5. Valve according to claim 1 or 2, characterized in that said arch (5) is fixed and located in a plane angularly offset by an angle (α) from the plane of said loop (1) while said movable membrane (3) is connected by a network of retaining wires (4) to said hoop (5).

6. Valve according to claim 5, characterized in that the length of the retaining wires (4) is such that at the end of the travel the membrane (3) is in abutment against the front face (12) of the loop (1) when closing.

7. Valve according to one of claims 5 or 6, characterized in that the fixed hoop (5) has through holes (50) for the passage of the retaining wires (4).

8. Valve according to claim 7, characterized in that the hoop (5) has notches (50a) at the outlet of the orifices (50).

9. Valve according to one of claims 5 to 8, characterized in that the angle (α) and the length of the retaining wires (4) are determined so that, at full opening, the membrane (3) make an angle γ between 40 ^* and 90 ^* with the rear face (11) or the rear edge of the loop (1).

10. Valve according to one of claims 5 to 9, characterized in that the ends of the hoop (5) are integral with the outer edges of the loop (1).

11. Valve according to one of claims 5 to 10, characterized in that the radius of curvature of the loop (1) is less than or equal to that of the fixed arch (5).

12. Valve according to one of the preceding claims, characterized in that the rear face (11) of the loop (1) has a width less than or equal to that of the front face (12).

13. Valve according to one of the preceding claims, characterized in that the width of the front face (12) of the loop (1) is continuously variable around its periphery with a maximum in the middle part.

14. Valve according to one of the preceding claims, characterized in that said loop (1) is open.

15. Valve according to one of the preceding claims, characterized in that the loop (1) is at least partially provided with a sheath (6) made of bio-compatible material which ensures in tight contact with the membrane (3) passage (2).

16. Valve according to one of the preceding claims, characterized in that the thickness of the loop (1) is continuously variable around its periphery with a maximum in its median part, defining between the posterior (11) and anterior faces (12) an angle β between 5 'and 20'.

17. Valve according to one of the preceding claims, characterized in that the cross section of said loop (1) is polygonal or triangular.

18. Valve according to one of claims 1 to 16, characterized in that the front face (12) of the loop (1) has a convex or concave curvature.

19. Valve according to one of the preceding claims, characterized in that said membrane (3) is obtained by autograft of part of the pericardium.

20. Valve according to one of claims 1 to 18, characterized in that said membrane (3) is made of flexible or rigid biocompatible material.

21. Valve according to one of the preceding claims, characterized in that said loop (1) is elastically deformable in torsion.

22. Valve according to one of the preceding claims, characterized in that said loop (1) is resiliently integral with the natural ring of the patient by a band (7) of biocompatible fixing.

23. Valve according to one of the preceding claims, characterized in that the arch (5) is flexible in the anteroposterior plane.