Mechanical prosthetic heart valves

Abstract

The present invention relates to a mechanical artificial heart valve (10), comprising: an annular support member (12) having an inner peripheral wall (14) centered on a longitudinal axis (X) and defining an internal passage; and at least two movable leaflets arranged in such a manner that each can achieve rotational movement around a rotation axis perpendicular to the longitudinal axis (X), so that the valve (10) can be transformed from a closed configuration to an open configuration, and vice versa. The annular support member (12) further comprises two lower support members (16a, 16b) of each leaflet on the inner peripheral wall (14), and when the valve (10) is in the closed configuration, the two lower support members (16a, 16b) contact the inner surface (46b) of the associated leaflet (40) at the corresponding support area (52). The distance (d1) between the center of the corresponding support area (52) and the leading edge (42) of each leaflet is greater than the thickness (t1) of the leaflet at the center of the corresponding support area (52).

Description

Technical Field

[0001] The present invention relates to a mechanical artificial heart valve. Background Art

[0002] A distinction is made between two major categories of artificial heart valves. One category encompasses valve prostheses made of flexible tissue arranged on rigid struts to mimic natural valves, known as tissue valves. The other category encompasses mechanical valve prostheses, which are devices that are independent of the shape of the natural valve and are made of wear-resistant, biocompatible, artificial materials.

[0003] Due to their anatomy and physiological mode of operation, tissue valves offer aspects of biological performance similar to native heart valves, as they conform to the natural structure of blood flow through the chambers of the heart and through the aorta.

[0004] This specific feature of the tissue valve allows the patient to be free of the need for anticoagulation therapy for the rest of his life, eliminating the risk of bleeding accidents caused by long-term use of these drugs and thus providing these patients with a better quality of life. In this way, the patient may forget that he has a heart valve fitted.

[0005] However, these tissue valves have a limited lifespan as they inevitably become calcified over time, meaning they need to be replaced after an average of around ten years. Due to their limited lifespan, this type of prosthesis is in most cases intended for use in subjects over the age of 65 or whose life expectancy is shorter than that of the tissue valve.

[0006] Unlike tissue valves, mechanical prosthetic valves do not degrade and have a lifespan that exceeds the human lifespan. Since the 1960s, several generations of mechanical heart valves have been designed. For example, we can mention valve prostheses made of caged balls (STARR-EDWARDS), followed by the second-generation prosthesis made of flat discs (BJORK-SHILEY) in the early 1970s, and then, a decade later, the third-generation prosthesis of the ST-JUDE MEDICAL model, a side-opening, bileaflet valve.

[0007] WO2008152224 discloses the latest generation of mechanical artificial heart valves. The heart valve includes an annular support member, which includes an inner peripheral surface centered on a longitudinal axis and defining an internal passage, and three leaflets arranged in such a manner that each leaflet is capable of rotational movement around a rotation axis perpendicular to the longitudinal axis, so that the valve can be converted from a closed configuration to an open configuration, and vice versa. When the valve is in the open configuration, the leaflets define a main orifice centered on the longitudinal axis between them, and blood can flow axially through the main orifice, while when the valve is in the closed configuration, the leaflets block the internal passage of the annular support member so as to prevent blood from flowing back through the main orifice. Each leaflet includes: a leading edge designed to abut against a portion of the inner peripheral surface of the annular support member when the valve is in the closed configuration; a central portion including an outer surface and an inner surface; and two lateral wings symmetrically located on both sides of the central portion and inclined relative to the central portion.

[0008] According to the construction of the valve described in this document, each leaflet is supported and hinged on two support means only at the level of its leading edge. That is, the leading edge of the leaflet has a leading edge contact surface, which contacts the upper surface of the support means when the leaflet moves between the open position and the closed position. As a result, when accelerated wear tests were carried out, significant wear of the leaflet at the level of its leading edge was observed. This wear can be attributed to the fact that the leading edge contact surface of the leaflet and the upper surface of the support means each have a small radius of curvature. A large part of this wear occurs at the moment of impact when the leaflet enters the closed position and the leading edge contact surface hits the upper surface of the support means. This is because at that moment, the instantaneous obstruction of the flow generates a water hammer effect, which generates significant loads on all the support points of the leaflet and in particular on the support means.

[0009] One object of the present invention is therefore to propose a mechanical prosthetic heart valve configured so as to limit wear at the level of the leaflets.

[0010] Another object of the present invention is to provide a mechanical prosthetic heart valve with improved leaflet guidance. Summary of the Invention

[0011] According to the present invention, these objects are achieved by means of a mechanical artificial heart valve comprising an annular support having an inner peripheral wall centered on a longitudinal axis and defining an internal passage, and at least two movable leaflets, preferably three movable leaflets, arranged in such a manner that each is capable of rotational movement about an axis of rotation perpendicular to the longitudinal axis, so that the valve can be converted from a closed configuration to an open configuration, and vice versa. When the valve is in the open configuration, the leaflets define a main orifice centered on the longitudinal axis between them, and blood can flow axially through the main orifice. When the valve is in the closed configuration, the leaflets at least partially block the internal passage of the annular support so as to prevent blood from flowing back through the main orifice. Each leaflet comprises a leading edge designed to abut a portion of the inner peripheral wall of the annular support when the valve is in the closed configuration, an inner surface extending from the leading edge, and an outer surface opposite to the inner surface and extending from the leading edge. The annular support comprises two opposing edges and as many extensions as the number of leaflets, which extend axially from one of the opposing edges. The annular support also comprises two lower supporting members for each leaflet on the inner peripheral wall, situated between two of said extensions and designed to come into contact against the corresponding leaflet when the valve is in the closed configuration.

[0012] When the valve is in the closed configuration, the two lower support members contact the inner surface of the associated leaflet at the respective support areas.The distance between the center of the respective support area and the leading edge of each leaflet is greater than the thickness of the leaflet at the center of the respective support area.

[0013] In one embodiment, the smallest of the two main radii of curvature of the surface of each of said respective support areas is greater than the thickness of said leaflet at said support area.

[0014] In one embodiment, the surface of the respective support area is substantially flat.

[0015] In one embodiment, the distance between the center of the respective support area and the leading edge of each leaflet is greater than 1 mm.

[0016] In one embodiment, each of the two lower support members associated with each leaflet includes a curved guide surface. Throughout the transition of the valve from the open configuration to the closed configuration, the leading edge of each leaflet contacts the curved guide surface of each lower support member.

[0017] In one embodiment, the two lower support members each include an apex located at a distal end of the curved guide surface.When the valve is in the closed configuration, each apex contacts a corresponding support area.

[0018] In one embodiment, the inner surface of each leaflet is substantially flat.A gap exists between the curved guide surfaces of the respective two lower support members and the inner surface of the corresponding leaflet in the closed configuration.

[0019] In one embodiment, when the heart valve is in the open position, the inner surface of each apex of the two lower support members abuts the leading edge of the leaflet.

[0020] In one embodiment, in a plane perpendicular to the longitudinal axis (X) of the annular support, the rotation axis of each leaflet is located at a distance from the longitudinal axis that is greater than 75% of the radius of the annular support.

[0021] In one embodiment, a contoured recess is present on two opposing sides of each extension, the recess acting as a guide surface for the respective two end portions of each leaflet when the heart valve transitions from an open configuration to a closed configuration, and vice versa.

[0022] In one embodiment, each leaflet comprises: a central portion comprising an outer surface and an inner surface; and two lateral winglets symmetrically located on either side of the central portion relative to a plane of symmetry of the leaflet. The winglets are inclined relative to the central portion and each comprises one of two end portions.

[0023] In one embodiment, the outer surface of each leaflet in the open position is at a distance from the inner peripheral wall of the annular support that is at least equal to 5% of the diameter of the annular support at the plane of symmetry of the leaflet. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Examples of embodiments of the present invention are indicated in the description and illustrated in the accompanying drawings, in which:

[0025] - Figure 1 illustrates a perspective view of a mechanical prosthetic heart valve in an open configuration with the leaflets defining between them a main orifice through which blood can flow;

[0026] - Figure 2 illustrates a perspective view of a mechanical prosthetic heart valve in a closed configuration, wherein the leaflets block the interior passages of the annular support so as to prevent blood from flowing back through the main orifice;

[0027] - Figure 3 Illustration of the view from above Figure 1 's view;

[0028] - Figure 4 Illustration of the view from above Figure 2 's view;

[0029] - Figure 5The cross-section view on AA shows Figure 4 's view;

[0030] - Figure 6 The figure shows a view of the annular support member viewed from above;

[0031] - Figure 7 The cross-section diagram on BB shows Figure 6 's view;

[0032] - Figure 8 A perspective view of the underside of a valve having only one leaflet is illustrated;

[0033] - Figure 9 A perspective view of the underside of the leaflet is shown;

[0034] - Figure 10 Pictured Figure 6 an enlarged view of a portion of the annular support;

[0035] - Figure 11 A view of the leaflet as viewed from above from one side of its outer surface is illustrated;

[0036] - Figure 12 The cross-section diagram on CC shows Figure 11 's view;

[0037] - Figure 13 illustrates a partial perspective view of a mechanical prosthetic heart valve in a closed configuration with a partial cross-section in the region of a lower support member associated with the leaflets;

[0038] - FIG. 14 illustrates a mechanical artificial heart valve according to the prior art similar to Figure 13 's view;

[0039] - Figure 15 Illustration of a mechanical prosthetic heart valve in its open configuration similar to Figure 13 's view;

[0040] - Figure 16 illustrates a partial perspective view of a mechanical prosthetic heart valve in a closed configuration with a partial cross-section in the region of an upper support member associated with the leaflets;

[0041] - Figure 17 Illustration of a mechanical prosthetic heart valve in its open configuration similar to Figure 16 's view;

[0042] - FIG. 18 illustrates a mechanical artificial heart valve according to the prior art similar to Figure 17 's view;

[0043] - Figure 19 illustrates a partial perspective view of a mechanical prosthetic heart valve with the leaflets in both a closed configuration and an open configuration;

[0044] - FIG. 20 illustrates a mechanical artificial heart valve according to the prior art similar to Figure 19 's view;

[0045] - Figure 21 illustrates a partial perspective view at the level of the flow channel as viewed from below a mechanical prosthetic heart valve;

[0046] - Figure 22 shows a partial cross-sectional view of a mechanical prosthetic heart valve in a plane perpendicular to the longitudinal axis of the annular support,

[0047] - Figure 23 illustrates a mechanical artificial heart valve according to the prior art similar to Figure 22 's view;

[0048] - Figure 24 and 25 They are Figure 22 to illustrate the forces exerted on the leaflets as the valve opens, and

[0049] - Figures 26 and 27 are cross-sectional views taken along lines CC and DD of Figure 23, respectively, to illustrate the forces exerted on the leaflets of a mechanical prosthetic heart valve according to the prior art when it opens. DETAILED DESCRIPTION

[0050] like Figures 1 to 4 As prominently illustrated in FIG, the mechanical prosthetic heart valve 10 comprises an annular ring support 12 defining a central internal passage 9 therein (see also FIG. Figure 6 ) for the circulation of blood under the action of cardiac contraction. When the heart valve 10 is in the open position, the flow through the heart valve 10 is qualified as antegrade flow, and its flow direction (also referred to as outflow direction in this article) is determined by Figure 1 Indicated by arrow A in . In contrast, when the heart valve 10 is closed, flow in the opposite direction (also referred to herein as the inflow direction) is qualified as retrograde flow.

[0051] The central internal passage for blood flow is formed by the inner peripheral wall 14 ( Figure 5 ) is defined as follows: the annular support member 12 is used as a support member for the three movable leaflets 40. Figure 1As depicted in , the annular support 12 of the heart valve 10 is centered on the longitudinal axis X and exhibits rotational symmetry about this axis. It will be noted that the valve may comprise only two leaflets, in which case the annular support 12 has an elliptical shape and the leaflets are ovoid in shape, or may comprise more than three leaflets without affecting the principles of the present invention.

[0052] The annular support 12 also comprises a peripheral wall 22 exhibiting a peripheral rim 24 intended to receive a sewing ring, not depicted, for example made of fabric, and allowing the surgeon to attach the valve to the cardiac tissue using sutures in a known manner.

[0053] exist Figure 1 、 3 In FIG, the heart valve 10 is depicted in an open configuration, wherein the leaflets 40 are in a known convex or open position, with blood flowing in an outflow direction through the valve and in an outflow direction. Figure 2 、 4 , the valve is depicted in a closed configuration, with the leaflets in a so-called lowered or closed position, thereby preventing blood from flowing through the heart valve 10 in the inflow direction.

[0054] like Figure 5 As can be seen in FIG, the annular support 12 comprises an upstream edge or leading edge 26, which connects the inner peripheral wall 14 to the outer peripheral wall 22 and is positioned on the upstream side of the downstream flow. The annular support 12 also comprises a downstream edge or trailing edge 28, which is located on the downstream side of the downstream flow and also connects the inner peripheral wall 14 to the outer peripheral wall 22 of the annular support.

[0055] Special References Figure 6 and Figure 7 The support member 12 further includes three guide extensions 30 extending from the trailing edge 28 in the outflow direction parallel to the longitudinal axis X. Thus, the guide extensions 30 form projections or serrations extending axially relative to the trailing edge 28, and have substantially the same width (dimension perpendicular to the axis X) at their base and tips. These guide extensions 30, in the form of surfaces of revolution, receive shaped recesses 32 with which the distal end portions of the movable leaflets, described later, cooperate, allowing the heart valve 10 to transition from a closed configuration to an open configuration, and vice versa.

[0056] Especially refer to Figure 11 Each leaflet 40 is identical to all other leaflets provided with the heart valve 10. The leaflet 40 comprises a central portion 46 to which are connected two lateral wings 48a, 48b, which are symmetrically located on either side of the central portion and are inclined relative to the central portion, as shown in FIG. Figure 12The center portion 46 has an outer surface 46a and an inner surface 46b, each of which is substantially planar, although in one embodiment, the inner surface 46b and / or the outer surface 46a may be slightly curved (e.g., Figure 12 , as shown by the inwardly curved inner surface 46b in the figure, to optimize flow characteristics.

[0057] The winglets 48a, 48b have an outer surface 47a and an inner surface 47b, and correspondingly have proximal portions 43a, 43b and distal portions 41a, 41b. The outer surface 47a of the distal portions 41a, 41b can be substantially planar or slightly curved. The proximal portions 43a, 43b are connected to the central portion 46 and form a gentle curve inward to the internal passage 9, so that the distal portions 41a, 41b are angled relative to the central portion 46. In particular, the outer surface 47a of the distal portions 41a, 41b of the winglets 48a, 48b are angled relative to the outer surface 46a of the central portion 46, and in one embodiment, the angle can be between 45 degrees and 60 degrees. The leaflets 40 are symmetrical about a symmetry plane Z. The leaflets 40 are rigid and can be formed from a rigid material such as PEEK.

[0058] refer to Figure 11 The leaflet 40 includes: a trailing point 45; two end portions 49a, 49b; a first trailing edge 44a extending between the trailing point 45 and the first end portion 49a; a second trailing edge 44b extending between the trailing point 45 and the second end portion 49b; and a curved leading edge 42 extending within the width W of the leaflet 40 between the first end portion 49a and the second end portion 49b. Together, these elements generally define a triangular shape with an elongated, curved leading edge 42. The outer and inner surfaces 46a, 46b of the central portion 46 and the winglets 48a, 48b are located between and excluding the trailing point 45 and the end portions 49a, 49b. Note that the leading edge 42 (as well as the trailing edge 44) can be rounded, with the outer and inner surfaces 46a, 46b being defined as extending from those rounded edges.

[0059] When the leaflets are in the open position, Figure 1 and 3 As depicted in FIG, the leading edge 42 is located on the upstream side of the antegrade flow and, in the closed position, mates with the inner wall 14 of the annular support 12 to form a seal that prevents blood flow therethrough, as shown in FIG. Figure 4 The leading edge 42 of the leaflet extends from a first end portion 49a to a second end portion 49b, which are located at the distal end of the respective lateral winglets 48a, 48b. The leading edge 42 is curved to match the curvature of the inner wall 14.

[0060] Furthermore, the leaflet 40 comprises, on the side of the leaflet opposite to the side on which the leading edge 42 is situated, a trailing edge 44 situated on the downstream side of the forward flow. The trailing edge 44 comprises two symmetrical portions 44a, 44b extending from the lateral winglets 48a, 48b, respectively, to a downstream end region where they meet to form a point 45. The point 45 is aligned with the plane of symmetry Z of the leaflet.

[0061] The heart valve 10 also comprises several lower (i.e. on the upstream or front side) support or support members which are different for each leaflet (each leaflet having its own support member 16a, 16b) and which are formed on the inner peripheral wall 14 of the annular support 12. In particular, with particular reference to Figure 6 Two lower supports or support members 16a, 16b (also referred to herein as lower supports or lower support members) are arranged between two adjacent guide extensions 30 to support each leaflet 40 when the heart valve 10 is in the closed configuration. The lower support members 16a, 16b are positioned on the upstream side of the leaflet 40 so as to face the inner surface 46b of the leaflet 40.

[0062] according to Figure 13 , the two lower support members 16a, 16b associated with each leaflet each include a support body 19 having a proximal end 19a, a middle portion, and a distal end forming an apex 18. The middle portion has a trailing edge defining a curved guide surface 17. The proximal end 19a is located proximal to the lower support members 16a, 16b at the junction between the support body 19 and the inner surface 14 and has a curve having a radius of curvature. The apex 18 extends further in the outflow direction than the leading edge 42 and is located distal to the guide surface 17, as shown in FIG. Figure 8 and 13 The middle portion of the guide surface 17 is located between the proximal end 19a and the apex 18 and curves away from the apex 18 in the inflow direction upstream of the forward flow.

[0063] In addition, the lower support members 16a, 16b are aligned with the central portion 46 of the leaflet 40. Thus, in the closed position, a lower support area 52 is formed where the central portion 46 of the inner surface 46b of the leaflet 40 contacts the apex 18 of the guide surface 17. The lower support area 52 includes an apex support area (i.e., the portion of the apex 18 that contacts the leaflet) and a leaflet support area (i.e., the portion of the leaflet inner surface 46b that contacts the apex 18). The apex support area and the leaflet support area cooperate to stop the leaflet 40 as the leaflet 40 moves from the open position to the closed position in the antegrade outflow direction; this in turn defines the closed position of the leaflet 40. However, because the middle portion bends away from the leaflet 40, a gap may exist between the middle portion of the guide surface 17 and the leaflet 40, as shown in FIG. Figure 13 That is, in Figure 13In the embodiment of FIG. 1 , the guide surface 17 extends inwardly into the central passage and upwardly (ie in the outflow direction) to an apex 18 .

[0064] Furthermore, apex 18 does not contact leading edge 42, but rather contacts a portion of inner surface 46b that is set back from leading edge 42. Thus, apex 18 is positioned far enough from leading edge 42 to avoid abrasion of leading edge 42 and for apex 18 to provide structural support, but not so far as to disrupt flow. Note also that, in one embodiment, apex 18 of lower support members 16a, 16b has a width. Thus, rather than being a finite point, this apex and leaflet support area can be linear, or apex 18 can be a flat surface (e.g., rectangular or square) to further support leaflet inner surface 46b and distribute the forces of leaflet 40 contacting apex 18, further reducing any hammering effect.

[0065] As the valve transitions from the open configuration to the closed configuration, the leading edge 42 of each leaflet slides at least partially along the guide surfaces 17 of the two lower support members 16a, 16b. Figure 8 and Figure 9 As can be seen in particular, the leading edge 42 and the inner surface 46b of the central portion 46 of each leaflet 40 are aligned with the Figure 6 In particular, the two lower support members 16a, 16b are shown in contact.

[0066] The configuration of the lower support members 16a, 16b has the advantage of significantly reducing leaflet wear by extending the contact area, unlike the heart valve according to WO2008152224, in which, as shown in FIG14 , the contact area is concentrated at the leading edge of the leaflet, which can lead to premature wear of the leaflet in this area, thereby reducing the optimal service life of the heart valve. This configuration in particular ensures that the support of the leaflet in the closed configuration occurs on its inner surface 46b. Since the inner surface 46b is substantially flat, it has a large radius of curvature (see FIG14 ). Figure 8 and Figure 9 ). Therefore, the inner surface 46b does not need to be completely flat, but has a sufficiently large radius to increase the contact surface. The radius of the inner surface 46a is at least greater than the thickness of the leaflet, which is greater than the radius at the leading edge. In the closed position, only the apex 18 of the guide surface 17 contacts the inner surface 46b of the central part 46. It is important that the leading edge 42 of the leaflet 40 does not contact the apex 18 and is not used to stop the movement of the leaflet; this therefore avoids wear of the leading edge 42, avoids any hammering effect on the leading edge 42 and ensures a reliable seal between the leading edge 42 and the inner wall 14 in the closed position. The very low risk of wear has the advantage of increasing the variety of materials that can be adopted.

[0067] The applicant found that for the heart valve 10 of the present invention, during the accelerated wear test, the wear on the leaflet 40 at the contact area of ​​the lower support members 16a, 16b can reach 30 microns; while under the same conditions, the wear on the contact area of ​​the support member disclosed in WO2008152224 exceeds 100 microns, which may cause the leaflet 42 to detach from the valve 10.

[0068] Thus, one aspect of the present disclosure is that the leading edge 42 of the leaflet is not used to stop the movement of the leaflet when it moves to the closed position. In one embodiment, the leading edge 42 (which may include a portion of the rotational curvature at the leading edge) remains in contact with the guide surface 17 during the rotation of the leaflet from the open position to the closed position, and the inner surface 46b contacts the apex 18 only in the closed position. In that case, the lower support area 52 is located away from the leading edge 42 and also away from any rotational curvature of the leading edge 42, so that the support area 52 does not include any portion of the leaflet that participates in the rotation of the leaflet to avoid additional wear on the rotating elements.

[0069] In accordance with Figure 9 and 13 In one embodiment, the distance d1 between the center of the support area 52 abutting each vertex 18 of the inner surface 46b of the central portion 46 and the leading edge 42 of each leaflet is greater than the thickness t1 of the leaflet at the level of the center of the support area 52 (e.g., the support area 52 cannot be part of the leading edge 42 because the radius of the leading edge 42 is approximately half the thickness). For a valve 10 having an outer diameter of 19-29 mm and a leaflet thickness of less than about 1 mm (too thick results in increased flow obstruction in the open position), this distance d1 is greater than 0.5 mm, and preferably greater than 1 mm. The radius of curvature of the inner surface of the leaflet at the level of the support area 52 is also greater than the thickness t1 of the leaflet at that point. In the context of the present disclosure, the radius of curvature of the inner surface of the leaflet at the support area (where the radius of a flat surface is infinite) is defined as the smallest of the major radii. This also covers small holes or indentations in the leaflet that form a spherical joint between the leaflet and the vertex. In other words, the smallest of the two main radii of curvature of the surface of the support area 52 is greater than the thickness of the leaflet at the support area 52 .

[0070] The heart valve 10 further includes a guide extension 30 ( Figure 5 and Figure 7 ), and are in the form of bow-shaped elements pointing upward (i.e., in the antegrade outflow direction) and shaped in the outflow direction. Each of the shaped elements 34 of the respective guide extension 30 includes lateral edges that are sufficiently widely spaced to serve as bearing supports for the lateral edges of the leaflets 40 when the heart valve 10 is in the closed configuration.

[0071] Furthermore, for each leaflet, two so-called upper (i.e. on the outflow side) support members 20a, 20b are arranged at the trailing edge 28 ( 20 ) of the annular support 12 in a manner axially offset relative to the two lower support members 16a, 16b along the longitudinal axis X of the annular support 12. Figure 6 ). Upper support members 20a, 20b are on the outflow side of the annular support (i.e., in the inflow direction), thus facing the outer surface 46a of the leaflet 40. In addition, the two lower support members 16a, 16b and the two upper support members 20a, 20b of each leaflet can be radially offset relative to each other, for example, to avoid the two upper support members 20a, 20b being placed behind the two lower support members 16a, 16b.

[0072] Especially about Figure 16 and 17 , each of the two upper support members 20a, 20b can be elongated, having a proximal end, a distal end, and a middle portion. The middle portion has a leading edge 21' and a trailing edge. The distal end can be a rounded apex 21 that is designed to abut against the outer surface 46a of the central portion 46 of each leaflet 40 throughout the entire process of the leaflets 40 pivoting about their respective rotational axes as the heart valve 10 transitions from the closed configuration to the open configuration. More specifically, each upper support apex 21 is designed to abut against the upper support area 54 (of the outer surface 46a of the central portion 46 of each leaflet) during at least 20%, or 35%, or even 50% of the travel of each leaflet as the heart valve 10 transitions from the closed configuration to the open configuration. Figure 16 ), which causes the leaflets to rotate about their axis of rotation. This contact can be continuous or intermittent. When the leaflets are pushed open by the flow, the contact is continuous during the first half of the opening.

[0073] The radius of curvature of the upper support region 54 is greater than the thickness of the leaflet at this region, as for the lower support region 52, or in other words, the smallest of the two main radii of curvature of the surface of the upper support region 54 is greater than the thickness of the leaflet at the upper support region 54. Figure 17 As shown in FIG, each apex 21 is in contact with the outer surface 46a of the central portion 46 of each leaflet during most of the opening stroke of the leaflet, which is different from the heart valve according to WO2008152224, in which, as shown in FIG18, the apex of the upper support member is in contact with the leaflet only at the very beginning of the opening phase and in the leading edge region of the leaflet. Therefore, the shape of the upper support members 20a, 20b is significantly different from that of the upper support members disclosed in WO2008152224.

[0074] In particular, the two upper support members 20a, 20b of each leaflet are in the form of projections extending inwardly from the inner wall 14 to overlap the leaflet 40. The two upper support members 20a, 20b are embedded from the downstream trailing edge 28 of the support member 12. In one embodiment, the leading edge 21' of the upper support members 20a, 20b is substantially linear to match the outer surface 46a of the leaflet. In addition, the leading edge 21' and, in one embodiment, the entire support members 20a, 20b are inclined relative to a plane orthogonal to the longitudinal axis X of the annular support member 12 to reliably match the outer surface 46a of the leaflet in the closed position.

[0075] like Figure 16 As shown in FIG, the leading edge 21 ' of the upper support member 20b is substantially parallel and flush with the outer surface 46a of the leaflet in the closed position. That is, in the closed configuration, the outer surface 46a of the leaflet is at a predetermined angle from the leading edge 42 to the trailing edge 44 in the outflow direction A (see FIG. Figure 1 、 2 , 5). In particular, leading edge 42 is horizontal, and trailing edge 44 is inclined in the outflow direction from tip portion 49 to trailing edge 45, such that trailing point 45 extends further in the outflow direction than leading edge 42 and tip portion 49 by a predetermined angle. Furthermore, the leading edge of upper support member 20b is at substantially the same predetermined angle as the leaflet in the outflow direction, such that support leading edge 21' is substantially parallel and flush with leaflet outer surface 46a.

[0076] When the apex 21 of the distal end of the projection coincides with the trailing edge 28 of the annular support 12, the apex 21 lies outside this orthogonal plane. In other words, the apex 21 extends outwardly in the outflow direction from the downstream trailing edge 28 of the support 12. The two upper support members 20a, 20b each include a lower face (i.e., a leading edge) that is parallel to the central portion 46 of the leaflet in the closed position.

[0077] refer to Figure 17 In the open position, the outer surface 46a of the leaflet is adjacent to the apex 21. Simultaneously, the bend at or near the leading edge 42 of the leaflet contacts the inner surface of the apex 18 of the lower support members 16a, 16b (see also FIG. Figure 15 ). In the open position, the leaflet contacts the lower support members 16a, 16b at its leading edge 42 and winglet 48a, with the extension 30 of the annular support member resting on the surface adjacent the recess 32. There is a gap with the apex 21 to prevent sticking. These features cooperate to prevent the leaflet 40 from moving further from the closed position to the open position. The apex 21 does not engage the leading edge 42 of the leaflet 40, but is designed to rest against the support area 54 of the outer surface 46a of the leaflet ( Figure 16- 54 indicates the center of the support area), the support area 54 is set back from the leading edge 42 of the leaflet by a distance d2, which is greater than the thickness t2 of the leaflet at the center of the support area 54; thereby avoiding wear of the leading edge 42 or the rotating element.

[0078] The configuration of the upper support members 20a, 20b offers the advantage over WO2008152224 that their points of contact with the leaflets are located in areas of low curvature of the leaflets, thereby limiting the risk of wear. Another advantage is that it provides better guidance of the leaflets when the heart valve 10 transitions from the closed configuration to the open configuration and avoids the leading edges of the leaflets abutting against the inner surface of the annular support, thereby causing undesirable reaction forces. Figure 24 and 25 , the upper supporting member (in Figure 22 The reaction of the flap 40 by the upper support member 20a (only the upper support member 20a is visible) is directly opposite to the opening pressure and therefore does not cause any significant reaction of the rotating surface of the recess 32 of the extension 30 against the trailing edge 28 of the flap 40. Therefore, the net force on the flap 40 is almost zero, which significantly reduces the wear of the flap.

[0079] In contrast, referring to Figures 23, 26, and 27, for the heart valve disclosed in WO2008152224, the reaction at the leading edge of each leaflet is not parallel to the opening pressure and causes a reaction at the trailing edge, which can lead to premature wear of the leaflet. It can also be appreciated from Figures 26 and 27 that the greater the deviation between the opening pressure and the reaction at the leading edge, the greater the reaction at the trailing edge. Consequently, this specific function of the upper support member 20a becomes more important the closer the leaflets approach a closed position.

[0080] To avoid the risk of snagging with other components maintaining the open position (particularly guide surface 32 and lower support members 16a, 16b), a functional gap may exist between upper support members 20a, 20b and the outer surface 46a of the leaflet in the open position. This arrangement also allows for a wider choice of leaflet materials, for example by using materials that are slightly more sensitive to wear but have a density closer to that of blood, providing much less inertia during the opening and closing phases. Materials such as PEEK have a density of 1.3, while pyrolytic carbon, commonly used in mechanical valve prostheses, has a density of 1.7.

[0081] like Figure 1 and 13 As depicted in FIG, the leading edge 42 of each leaflet 40 is disposed between two lower support members 16a, 16b and two upper support or support members 20a, 20b. It will be noted that the members for guiding the rotation of each leaflet define Figure 22and is situated completely outside the corresponding leaflet, between the latter and the annular support 12 .

[0082] In operation, the heart valve 10 is sometimes in the closed position, which Figure 2 、 4 , 5, 8, 13. The leaflets 40 come together at the trailing edge 44, and the leading edge 42 of the leaflet 40 is flush with the inner wall 14 to provide a reliable seal against backflow of blood. Any blood flow in the inflow (upstream antegrade flow) direction will press the leaflets closed and prevent further movement at the lower support area 52 by the two lower support members 16a, 16b that support each leaflet 40. Specifically, the apex 18 support area supports the inner surface 46b support area to prevent further movement of the leaflet. The lower support members 16a, 16b are located between the end portions 49a, 49b of the leaflet 40, and the lower support area 52 is set a predetermined distance inward from the leading edge 42 of the leaflet. In addition, the central support member 34 also supports the leaflet wings 48a, 48b. Refer to Figure 13 , the leaflet leading edge 42 abuts the proximal end of the guide surface 17. Because the lower support area 52 (between the apex 18 and the inner surface 46b) is distal to the leading edge 42, wear on the leading edge 42 is reduced. A small gap exists between the upper support members 20a, 20b and the outer surface 46a of the leaflet 40, so that the upper support members 20a, 20b are not used in the closed position.

[0083] At some point, the leaflets 40 begin to move out of the closed position and toward the open position. The force of the blood flow causes the leaflets 40 to move in the outflow direction. This separates the leaflets 40 from the apex 18. The leaflets 40 move in the outflow direction A until Figure 16 As shown in FIG, the outer surface 46a contacts the supporting front edge of the upper support member 20a, 20b. Figure 17 , the outer surface 46a contacts the apex 21 of the upper support members 20a, 20b. This causes the leaflet 40 to rotate about the apex 21 at the upper support area 54, with the winglets 48a, 48b guided by the recess 32 of the guide extension 30. The upper support area 54 is set back a predetermined distance from the leading edge 42. The trailing edge 44 of the leaflet 40 rotates to extend in the outflow direction. And the leading edge 42 rotates toward the inner surface of the lower support apex 18. Since the leaflet 40 is separated from the guide surface 17, the leading edge 42 does not contact the guide surface 17 during rotation, which reduces wear on the leading edge 42. The leaflet 40 stops when the winglet 48 contacts the edge of the recess 32 and the leaflet 40 contacts the inner surface of the lower support apex 18.

[0084] When blood flows in the inflow direction, the blood pushes the leaflets from the open position to the closed position. The leading edge 42 of the leaflet is guided by the guide surface 17 of the lower support members 16a, 16b. When the inner surface 46b of the leaflet contacts the apex 18, the movement of the leaflet stops.

[0085] Note that in the illustrated embodiment, there are three leaflets 40 and three guide extensions 30. Furthermore, each leaflet 40 has two lower support members 16a, 16b and two upper support members 20a, 20b. Having two lower support members and two upper support members 16a, 16b, 20a, 20b distributes wear and pressure more evenly across the leaflets and reduces wear on the leaflets 40. However, any suitable number of elements may be provided, including more or fewer leaflets 40 and guide extensions 30. And each leaflet may have one or more lower support members and / or upper support members.

[0086] Applicants have discovered that, according to the valve configuration described in WO2008152224, as the leaflets rotate at the onset of systole, the leading edges of the two winglets of each leaflet slide against the inner circumferential surface of the annular support. It has now been discovered that the constant contact between the leading edge and the inner circumferential wall of the annular support according to FIG20 can generate flow recirculation in the obstructed region behind the leaflets, which can promote platelet aggregation and thrombus formation. FIG20 depicts a partial cross-sectional view of the mechanical prosthetic heart valve disclosed in WO2008152224, taken on a plane perpendicular to the longitudinal axis of the annular support.

[0087] according to Figure 11 、 12 and 22, lateral winglets 48a, 48b of each leaflet 40 ( Figure 12 ) has been determined so that the leading edge 42 and outer surface of each leaflet 40 is at least 0.2 mm, preferably at least 0.3 mm, or 0.4 mm or even 0.5 mm from the inner peripheral wall over at least 75% of the total width W of each leaflet, and preferably at least 80%, or 90% when the heart valve 10 is in the open configuration. The curvature of the lateral winglets 48a, 48b of each leaflet 40 has also been determined to promote the opening of a flow channel 50 (between the inner peripheral wall 14 of the annular support 12 and the outer surface 47a of the winglets 48a, 48b of the leaflets 40) Figure 21 and 22 ).

[0088] In particular, when the leaflets are in Figure 1 In the open position, each leaflet contacts the inner peripheral wall 14 of the annular support 12 only through the two end portions 49a, 49b of the leaflet, as shown in FIG. Figure 22Advantageously, the contact area of ​​the leaflets in the open position is smaller than that at the two end portions 49a, 49b ( Figure 11 and 12 ), i.e., less than 7.5% at each end portion 49a, 49b. In a preferred embodiment, this contact area of ​​the leaflets is less than 10% of the width W of the leaflets 40, i.e., less than 5% at each end portion 49a, 49b of the leaflets, preferably less than 7.5% of the width W of the leaflets 40, i.e., less than 3.75% at each end portion 49a, 49b of the leaflets, and even more preferably less than 5% of the width W of the leaflets 40, i.e., less than 2.5% at each end portion 49a, 49b of the leaflets. Figure 22 In the context of the present invention, the extension 30 of the annular support 12 is an integral part of the inner peripheral wall 14 of the support and, therefore, the leaflet contact area at the extension 30 must be included in the above percentages.

[0089] In addition, if Figure 3 、 11 As shown in Figures 1 and 12, the outer surface 46a of each leaflet 40 in the open position is at a distance L from the inner peripheral wall 14 of the annular support 12 that is at least equal to 5% of the diameter of the annular support at the plane of symmetry Z of the leaflet.

[0090] like Figure 22 As can be seen in the figure, the rotation axis of each leaflet 40 is also located in a plane parallel to the central portion 46 of the leaflet. This plane intersects the two upper support members 20a, 20b arranged on the inner peripheral wall 14 of the annular support 12. The rotation axis of each leaflet is also located at a distance from the longitudinal axis X of the annular support 12 of the heart valve 10 (in a plane perpendicular to this axis) that is greater than 75% of the radius of the annular support 12.

[0091] like Figure 3 As best shown in FIG, the leaflets 40 are configured in the open position to form a substantially triangular shape with rounded corners when arranged in the support 12. The distal end portions 49 of the leaflets 40 engage the extensions 30, and the planar center portion 46 of the leaflets 40 extends substantially linearly between the extensions 30. Thus, the planar center portion 46 extends inwardly from the distal end portions 49 of the winglets 48 to the center of the center portion 46 that is farthest from the inner wall 14 of the support 12. In addition, as shown Figure 22 As best shown in FIG. 4 , in the open position, an outer surface 47 of the distal portion 41 extends substantially parallel to the inner wall 14 and contacts the recess 32 .

[0092] Furthermore, the curved proximal portion 43 is configured to begin at the end of the recess, causing the winglets 48 to immediately and sharply turn away from the inner wall 14 of the support member 12, thereby forming a gap 50 between the outer surface 47 of the proximal portion 43 and the inner wall 14 of the support member 12. This gap 50 forms a channel through which blood can flow. Thus, the distal portion 41 extends axially outward from the extension 30 and then bends inward at the curved proximal portion 43. The central portion 46 extends linearly between the extensions and continues to move away from the inner wall 14, thereby forming a larger gap between the outer surface 46a of the central portion 46 and the inner wall 14. The channel formed by the gap 50 allows blood to flow more easily in the outflow direction. Furthermore, the straight central portion 46 minimizes interference with blood flow. Thus, a configuration in which the leaflets 40 are arranged such that the proximal portion 49 is located at the extension 30 and immediately bends linearly inward to the next adjacent extension 30 provides a widened gap 50, or channel, between the leaflets 40 and the inner wall 14. In one embodiment, the distal portion 41 may also be bent inward to further widen the gap 50 just to the side of the extension 30 .

[0093] like Figure 3 As further shown in FIG, the center of central portion 46 is the maximum distance between leaflets 40 and inner wall 14. Lower supports or support members 16a, 16a are located at inner wall 14 at the outermost portion of central portion 46, proximate to curved proximal portion 43 of winglet 48, to provide adequate support when leaflets 40 are brought into the closed position. Upper support members 20a, 20b may be positioned closer together at central portion 46.

[0094] The curvature of the proximal portion 43 of the lateral winglets 48a, 48b of each leaflet 40 and the shape and positioning of the two lower support members 16a, 16b make it possible to form two flow channels 50 at the level of the terminal portion 49a, 49b of each leaflet 40 between each of the two lower support members 16a, 16b and one of the guide extensions 30 of the annular support 12 when the heart valve 10 is transformed from the closed configuration into the open configuration. In practice, the gap 50 between the leading edge 42 of the leaflet 40 and the trailing edge 28 of the annular support 12 is defined by the specific curvature of the leaflet, the profile of the trailing edge 28 and the displacement of the axis of rotation which brings the leaflet a little further downstream relative to the inner peripheral wall 14 in the open position. In particular, Figure 19 、 21 The size of each flow channel 50 illustrated in Figures 2 and 22 increases as the leaflets 40 are progressively pivoted about their respective axes of rotation until the point where the heart valve 10 is in the open configuration. These flow channels have the advantage of minimizing potential areas for platelet aggregation.

[0095] In contrast, the heart valve according to WO2008152224 has no flow channels at the level of the distal end portion of each leaflet between each of the two lower support members and one of the guiding extensions of the annular support when the heart valve transitions from the closed configuration to the open configuration, as can be seen in Figure 23. This is mainly due to the contact area of ​​the leaflets, which is approximately 20% of the total width of the leaflets, i.e., 10% at each distal end portion of the leaflet, as shown in Figure 23. The absence of drainage channels in these critical areas may lead to platelet aggregation, which may induce thrombosis.

[0096] In order to manufacture the rigid leaflet valve according to the present invention, there are a variety of materials that can be used. For the annular support, for example, a biocompatible metal such as titanium or stellite is selected. Solid carbon or a carbon coating on graphite can also be used.

[0097] The leaflets themselves are also rigid and can be made of biocompatible materials, such as solid carbon or graphite with a pyrolytic carbon coating. They can also be made of biocompatible synthetic polymers that also have wear resistance comparable to pyrolytic carbon. Thus, materials such as "PEEK" (which stands for polyetheretherketone) have a low density of approximately 1.3 and are particularly well-suited for making the leaflets. This material can be reinforced with carbon to increase the leaflet's wear resistance.

[0098] It will be noted that the valve according to the invention can be made of titanium in the case of the annular support 12 and of PEEK in the case of the leaflets, which provides a material pairing perfectly adapted to the friction and wear encountered in valves of this type. Furthermore, PEEK can also be used as the material for the leaflets and pyrolytic carbon for the support, or even for both.

[0099] It is further noted that the drawings may illustrate, and the description and claims may use, several geometric or relational terms and directional or positioning terms, such as shaped, square, rectangular, triangular, linear, curved, curvature, circular, parallel, perpendicular, orthogonal, transverse, axial, round, flat, leading, trailing, forward, upper, lower, upper, lower, interior, exterior, interior, exterior, side, distal, and proximal. These terms are merely for convenience in describing the embodiments shown in the drawings and are not intended to limit the present invention. Therefore, it should be understood that the present invention can be described in other ways without those geometric, relational, directional, or positioning terms. Moreover, geometric or relational terms may not be accurate. For example, a wall or surface may not be completely flat, perpendicular, or parallel to each other, but still be considered substantially perpendicular or parallel due to, for example, surface roughness, tolerances allowed in manufacturing, etc. Moreover, other suitable geometries and relationships may be provided without departing from the scope of the appended claims.

[0100] Reference Signs List

[0101] Mechanical prosthetic heart valve10

[0102] Annular support 12

[0103] Inner wall 14

[0104] Lower support members 16a, 16b

[0105] Support 19

[0106] Proximal 19a

[0107] Guide surface 17

[0108] Vertex 18

[0109] Upper support members 20a, 20b

[0110] Vertex 21

[0111] Leading edge 21'

[0112] Outer peripheral wall 22

[0113] Peripheral ribs 24

[0114] Leading Edge 26

[0115] Trailing Edge 28

[0116] Guide extension 30

[0117] Molding recess 32

[0118] Guide Arc

[0119] Support member 34

[0120] Active leaflet 40

[0121] Leading Edge 42

[0122] Trailing Edge 44

[0123] Symmetrical parts 44a, 44b

[0124] End 45

[0125] Center section 46

[0126] Outer surface 46a

[0127] Inner surface 46b

[0128] Lateral winglets 48a, 48b

[0129] Distal end portions 41a, 41b

[0130] Proximal portions 43a, 43b

[0131] Outer surface 47a

[0132] inner surface 47b

[0133] End portions 49a, 49b

[0134] Flow channel 50

[0135] Lower support area 52

[0136] Upper support area 54 .

Claims

1. A mechanical artificial heart valve (10), comprising: - an annular support (12) comprising an inner peripheral wall (14) centered on the longitudinal axis (X) and defining an internal passage, - at least two movable leaflets arranged in such a manner that each is capable of a rotational movement about an axis of rotation perpendicular to the longitudinal axis (X) so that the valve (10) can pass from a closed configuration to an open configuration, and vice versa, when the valve is in the open configuration, the leaflets (40) define between them a main orifice centered on the longitudinal axis and through which blood can flow axially, and when the valve (10) is in the closed configuration, the leaflets (40) at least partially block the internal passage of the annular support (12) so as to prevent blood from flowing back through the main orifice, Each leaflet (40) comprises a leading edge (42) designed to abut against a portion of the inner peripheral wall (14) of the annular support (12) when the valve is in a closed configuration, an inner surface (46b) extending from the leading edge (42), and an outer surface (46a) opposite the inner surface (46b) and extending from the leading edge (42), The annular support (12) comprises two opposing edges (26, 28) and as many extensions (30) as there are leaflets (40), the extensions (30) extending axially from one of the opposing edges, the annular support (12) further comprising two lower support members (16a, 16b) for each leaflet on the inner peripheral wall (14), the two lower support members (16a, 16b) being located between two of the extensions (30) and being designed to come into contact against the corresponding leaflet when the valve (10) is in the closed configuration, It is characterized in that When the valve (10) is in a closed configuration, the two lower support members (16a, 16b) contact the inner surface (46b) of the associated leaflet (40) at the corresponding support area (52), wherein the distance (d1) between the center of the corresponding support area (52) and the leading edge (42) of each leaflet is greater than the thickness (t1) of the leaflet at the center of the corresponding support area (52).

2. The mechanical artificial heart valve (10) according to claim 1, wherein The mechanical artificial heart valve (10) comprises three movable leaflets (40).

3. The mechanical artificial heart valve (10) according to claim 1, wherein: The smallest of the two main radii of curvature of the surface of each of the respective support areas (52) is greater than the thickness (t1) of the leaflet at the respective support area (52).

4. The mechanical artificial heart valve (10) according to claim 1, wherein The surface of the corresponding support area (52) is flat.

5. The mechanical artificial heart valve (10) according to claim 1, wherein The distance (d1) is greater than 1 mm.

6. The mechanical artificial heart valve (10) according to claim 1, wherein Each of the two lower support members (16a, 16b) associated with each leaflet (40) includes a curved guide surface (17), and the leading edge (42) of each leaflet contacts the curved guide surface (17) of each lower support member (16a, 16b) throughout the transition of the valve from the open configuration to the closed configuration.

7. The mechanical artificial heart valve (10) according to claim 6, wherein: The two lower support members (16a, 16b) each include an apex (18) located at the distal end of the curved guide surface (17), wherein each apex (18) contacts the corresponding support area (52) when the valve (10) is in the closed configuration.

8. The mechanical artificial heart valve (10) according to claim 6, wherein: The inner surface (46b) of each leaflet (40) is flat, and wherein a gap exists between the curved guide surfaces (17) of the respective two lower support members (16a, 16b) and the inner surface (46b) of the corresponding leaflet (40) in the closed configuration.

9. The mechanical artificial heart valve (10) according to claim 7, wherein: When the heart valve (10) is in the open position, the inner surface of each apex (18) of the two lower support members (16a, 16b) abuts the leading edge (42) of the leaflet (40).

10. The mechanical artificial heart valve (10) according to claim 1, wherein In a plane perpendicular to the longitudinal axis (X) of the annular support (12), the rotation axis of each leaflet (40) is located at a distance from the longitudinal axis (X) that is greater than 75% of the radius of the annular support (12).

11. The mechanical artificial heart valve (10) according to claim 1, wherein: Molded recesses (32) are formed on two opposing sides of each extension (30), which serve as guide surfaces for the respective two end portions (49a, 49b) of each leaflet (40) when the heart valve (10) is transformed from an open configuration to a closed configuration, and vice versa.

12. The mechanical artificial heart valve (10) according to claim 11, wherein Each leaflet comprises: a central portion (46) comprising an outer surface (46a) and an inner surface (46b); and two lateral wings (48a, 48b) symmetrically located on either side of the central portion (46) relative to a plane of symmetry (Z) of the leaflet and inclined relative to the central portion, each lateral winglet (48a, 48b) comprising one of the two end portions (49a, 49b).

13. The mechanical prosthetic heart valve (10) according to claim 1, wherein The outer surface (46a) of each leaflet (40) in the open position is at a distance from the inner peripheral wall (14) of the annular support (12) that is at least equal to 5% of the diameter of the annular support at the plane of symmetry (Z) of the leaflet.

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