Mechanical heart valve

Abstract

The present invention relates to a mechanical artificial heart valve (10), comprising: an annular support (12) having an inner peripheral wall (14) centered on a longitudinal axis (X) and defining an internal passage; and at least two active leaflets, preferably three active leaflets (40) arranged in such a manner that each leaflet can achieve a 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. 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 the closed configuration, an inner surface (46b) extending from the leading edge (42), and an outer surface (46a) opposite to the inner surface (46b) and extending from the leading edge (42). The annular support member (12) comprises: at least one lower support member (16a, 16b) for each leaflet on the inner peripheral wall (14), the lower support member (16a, 16b) being located between two of the extensions (30) and being designed to contact against the corresponding leaflet when the valve (10) is in a closed configuration; and two upper support members (20a, 20b). The two upper support members (20a, 20b) each comprise a distal end (21). Each distal end (21) is designed to contact against a support area of ​​an outer surface (46a) of a leaflet (40). The center of the support area (54) is set back from the leading edge (42) of the leaflet (40) by a distance (d2), the distance (d2) being greater than the thickness (t2) of the leaflet at the center of the support area.

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 the natural valve, 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 artificial materials that are wear-resistant and biocompatible.

[0003] Due to their anatomical configuration 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 heart chambers and through the aorta.

[0004] This specific feature of the tissue valve allows the patient to be exempt from the need for anticoagulation therapy for the rest of his life, and this eliminates the risk of bleeding accidents due to long-term use of these drugs and therefore provides 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 ten years or so. Due to their limited lifespan, this type of prosthesis is in most cases intended for use in subjects over 65 years of age or with a life expectancy shorter than that of a tissue valve.

[0006] Unlike tissue valves, artificial valve devices of the mechanical type do not deteriorate and have a life span that exceeds the human life span. Since the 1960s, several generations of mechanical heart valves have been designed. For example, one can mention the valve prosthesis consisting of a caged ball (STARR-EDWARDS), then in the early 1970s, the second generation of prostheses consisting of a flat disc (BJORK-SHILEY), and then, ten years later, the third generation of prostheses with a side-opening bi-leaflet of the ST-JUDE MEDICAL type.

[0007] WO2008152224 discloses the latest generation of mechanical artificial heart valves. The heart valve includes an annular support, 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 an 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 a closed configuration, the leaflets block the internal passage of the annular support 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 when the valve is in a closed configuration; a central portion including an outer surface and an inner surface; and two lateral winglets symmetrically located on both sides of the central portion and inclined relative to the central portion.

[0008] According to the valve construction described in this document, during each cardiac cycle, the leaflets open and close to control blood flow. During the opening and closing of the heart valve, the movement of each leaflet is guided in particular by the upper support means and the lower support means. However, the shape and position of the upper support means on the inner circumferential surface of the annular support are not optimal, because these means are in contact with the leaflets only near the leading edge. As a result, the loads applied to the leaflets in this area at the beginning and end of opening are concentrated on the small radius of curvature area on the leaflets and the support, resulting in very high contact pressures and, therefore, significant wear. In addition, according to the construction of the valve described in this document, the upper support means are in contact with the leaflets only during the beginning of the opening of the leaflets. When the leaflet has already begun its opening movement, it is then guided between the circular portion of the extension and a portion of the leading edge of the leaflet in contact with the wall of the annular support. This construction results in a large reaction force between the guide means, which promotes premature wear, especially at the level of the leaflet area that slides along the circular portion of the extension.

[0009] It was also found that under the influence of the leaflet closing, the upper support device was subjected to significant loads to prevent the leaflet from continuing to move beyond the closed position. Due to the small contact area, significant wear occurred in this area.

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

[0011] Another object of the present invention is to propose a mechanical prosthetic heart valve with an improved wear profile. Summary of the invention

[0012] According to the present invention, these objects are achieved by means of a mechanical artificial heart valve, which includes an annular support having an inner peripheral wall centered on the longitudinal axis and defining an internal passage, and at least two active leaflets, preferably three active leaflets, which are arranged in such a way that each can realize a 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 between them a main orifice centered on the longitudinal axis, 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 includes a leading edge designed to abut against 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 includes two opposite edges and as many extensions as the number of leaflets, which extend axially from one of the opposite edges. The annular support also includes at least one lower support member for each leaflet on the inner peripheral wall, which is located between the two extensions and is designed to contact the corresponding leaflet when the valve is in a closed configuration, and two upper support members for each leaflet.

[0013] The two upper support members each include a distal end. Each distal end is designed to abut against a support area on the outer surface of the leaflet. The center of the support area is set back from the leading edge of the leaflet by a distance greater than the thickness of the leaflet at the center of the support area.

[0014] In one embodiment, the smallest of the two main curvatures of the support region surface is greater than the thickness of the leaflet at the support region.

[0015] In one embodiment, each of the two upper support members extends inwardly from the inner peripheral wall and has a proximal end, a middle portion, and a distal end having an apex. When the heart valve is in a closed configuration, each middle portion extends from a proximal end inclined at a predetermined angle in the flow direction to be substantially parallel to the outer surface of the leaflet. When the leaflet moves from the closed configuration to the open configuration, the outer surface of the leaflet contacts the leading edge of each upper support member and pivots around the apex of the upper support member to rotate the leaflet to the open configuration.

[0016] In one embodiment, each apex of the two upper support members is designed to abut against a support area during at least 20% of the opening travel of the leaflets as they transition from a fully closed configuration to a fully open configuration.

[0017] In one embodiment, the apex of each of the two upper support members is designed to abut against the support area during at least 50% of said opening stroke of each leaflet.

[0018] In one embodiment, the leading edge of each upper support member is linear.

[0019] In one embodiment, the valve includes exactly two lower support members per leaflet.

[0020] In one embodiment, in a plane perpendicular to the longitudinal axis of the valve, the axis of rotation 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, contoured recesses are created on two opposite sides of each extension. The recesses serve as guiding surfaces for the respective two end portions of each leaflet when the valve transitions from a closed configuration to an open configuration, and vice versa.

[0022] 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.

[0023] In one embodiment, the material used for the leaflets has a density less than 1.5. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] - Figure 1 illustrates a perspective view of a mechanical prosthetic heart valve in an open configuration, wherein the leaflets define 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 passage of the annular support so as to prevent blood from flowing back through the main orifice;

[0027] - Figure 3 The diagram shows the Figure 1 's view;

[0028] - Figure 4 The diagram shows the Figure 2 's view;

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

[0030] - Figure 6 A view of the annular support member viewed from above is illustrated;

[0031] - Figure 7The 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] - Fig. 9 A perspective view of the underside of the leaflet is shown;

[0034] - Fig.10 Picture shows Figure 6 an enlarged view of a portion of the annular support;

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

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

[0037] - Fig.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 valve leaflets;

[0038] - Fig.14 The diagram shows a mechanical artificial heart valve according to the prior art similar to Fig.13 's view;

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

[0040] - Fig.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 valve leaflets;

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

[0042] - Fig.18 The diagram shows a mechanical artificial heart valve according to the prior art similar to Fig.17 's view;

[0043] - Fig.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 The diagram shows a mechanical artificial heart valve according to the prior art similar to Fig.19 's view;

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

[0046] - Fig. 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] - Fig.23 The diagram shows a mechanical artificial heart valve according to the prior art similar to Fig. 22 's view;

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

[0049] - Fig.26 and 27 They are Fig.23 Cross-sectional views on CC and DD of to illustrate the forces exerted on the leaflets of a mechanical artificial heart valve according to the prior art when it opens. DETAILED DESCRIPTION

[0050] like Figures 1 to 4 As prominently illustrated in FIG. 1 , the mechanical prosthetic heart valve 10 includes an annular ring support 12 that defines a central internal passage 9 therein (see also FIG. Figure 6 ) for circulating blood flow 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 FIG. Conversely, 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 three movable leaflets 40. Figure 1 , 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 include only two leaflets, in which case the annular support 12 has an elliptical shape and the leaflets are ovoid in shape, or may include 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. 1 , heart valve 10 is depicted in an open configuration, wherein leaflets 40 are in a known convex or open position, blood flow is in an outflow direction through the valve, and in an inflow direction through the valve. 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 the annular support 12, 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 12 also 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 protrusions or serrations extending axially relative to the trailing edge 28, and the widths of their bases and tips (dimensions perpendicular to the axis X) are substantially the same. These guide extensions 30 receive, in the form of surfaces of revolution, molded recesses 32 with which the terminal portions of the movable leaflets to be described later cooperate, so that the heart valve 10 can be transformed from a closed configuration to an open configuration, and vice versa.

[0056] Especially refer to Fig.11 Each leaflet 40 is identical to all other leaflets of the heart valve 10. The leaflet 40 comprises a central portion 46 to which two lateral wings 48a, 48b are connected, the two lateral wings 48a, 48b being symmetrically located on either side of the central portion and inclined relative to the central portion, as shown in FIG. Fig.12 The 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. Fig.12 The inwardly curved inner surface 46b is shown in the figure to optimize the 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 form an angle relative to the central portion 46. In particular, the outer surface 47a of the distal portions 41a, 41b of the winglets 48a, 48b form an angle 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 leaflet 40 is symmetrical about the symmetry plane Z. The leaflet 40 is rigid and can be formed of a rigid material such as PEEK.

[0058] refer to Fig.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 between the first end portion 49a and the second end portion 49b within the width W of the leaflet 40. Together, these elements generally define a triangular shape with an elongated curved leading edge 42. The outer and inner surfaces 46a, 46b of the center portion 46 and the winglets 48a, 48b are located between and do not include 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, and the outer and inner surfaces 46a, 46b are defined as extending from those rounded edges.

[0059] When the leaflets are in the open position, Figure 1 and 3 As depicted in FIG. 1 , the leading edge 42 is located on the upstream side of the antegrade flow and, in the closed position, the leading edge 42 matches 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 antegrade flow. The trailing edge 44 comprises two symmetrical portions 44a, 44b extending respectively from the lateral winglets 48a, 48b to a downstream end zone 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 a 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 Fig.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 of 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 at the distal end of 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. Therefore, in the closed position, the lower support area 52 is formed at the position 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). When the leaflet 40 moves from the open position to the closed position in the antegrade outflow direction, the apex support area and the leaflet support area cooperate to stop the leaflet 40; this in turn defines the closed position of the leaflet 40. However, because the middle portion is bent 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. Fig.13 That is, in Fig.13 In the embodiment of FIG. 1 , the guide surface 17 extends inwardly into the central passage and upwardly (ie in the outflow flow direction) to an apex 18 .

[0064] In addition, the apex 18 does not contact the leading edge 42, but rather contacts a portion of the inner surface 46b that is set back from the leading edge 42. Thus, the apex 18 is positioned far enough from the leading edge 42 to avoid wear of the leading edge 42 and for the apex 18 to provide structural support, but not too far to interrupt flow. It is also noted that in one embodiment, the apex 18 of the lower support members 16a, 16b has a width. Thus, rather than being a finite point, the apex and leaflet support area can be linear, or the apex 18 can be a flat surface (e.g., rectangular or square) to further support the leaflet inner surface 46b and distribute the force of the leaflet 40 contacting the apex 18 and further reduce 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 Fig. 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 Figure 6 In particular, the two lower support members 16a, 16b shown in FIG. 1 are 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 the contact area is substantially reduced. Fig.14 As shown in , the contact area is concentrated at the leading edge of the leaflet, which may 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 Figure 8 and Fig. 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 diversity 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 the leaflet is moved 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 positioned away from the leading edge 42 and also away from any rotational bend 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 element.

[0069] In accordance with Fig. 9 and 13 In one embodiment, the distance d1 between the center of the support area 52 against 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 (for example, 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 approximately 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 main radii. This also covers small holes or small recesses 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 region 52 is greater than the thickness of the leaflet at the support region 52 .

[0070] The heart valve 10 further includes a guide extension 30 ( Figure 5 and Figure 7 ), and which take the form of bow-shaped elements pointing upward (i.e., in the antegrade outflow direction) and are shaped in the outflow direction. Each of the shaped elements 34 of the respective guide extension 30 includes lateral edges that are spaced sufficiently widely 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 ( 20.5 cm) 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 ). The upper support members 20a, 20b are on the outflow side of the annular support (i.e., in the inflow direction), facing the outer surface 46a of the leaflet 40. Furthermore, the two lower support members 16a, 16b and the two upper support members 20a, 20b of each leaflet may be radially offset relative to each other, for example, to avoid that the two upper support members 20a, 20b are placed following the two lower support members 16a, 16b.

[0072] Special about Fig.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, which 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 a closed configuration to an open configuration. More specifically, each upper support apex 21 is designed to abut against an upper support area 54 ( 46a ) 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 a closed configuration to an open configuration. Fig.16 ), which causes the leaflet to rotate about its axis of rotation. This contact can be continuous or intermittent. When the leaflet is 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. Fig.17 As shown in FIG. 1 , during most of the opening stroke of the leaflets, each vertex 21 is in contact with the outer surface 46a of the central portion 46 of each leaflet, which is different from the heart valve according to WO2008152224, where Fig.18 As shown in , the apex of the upper support member contacts the leaflets only at the very beginning of the opening phase and in the leading edge region of the leaflets. Therefore, the shape of the upper support members 20a, 20b is significantly different from the shape 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 protrusions extending inwardly from the inner wall 14 to overlap with 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 member 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 Fig.16 As shown in FIG. 1 , the leading edge 21 'of the upper support member 20b is substantially parallel and flush with the outer surface 46a of the flap in the closed position. That is, in the closed configuration, the outer surface 46a of the flap forms a predetermined angle from the leading edge 42 to the trailing edge 44 in the outflow direction A (see FIG. 1 ). Figure 1 , 2 , 5). In particular, the leading edge 42 is horizontal, and the trailing edge 44 is inclined in the outflow direction from the end portion 49 to the trailing edge 45, so that the trailing point 45 extends further in the outflow direction than the leading edge 42 and the end portion 49 at a predetermined angle. In addition, the leading edge of the upper support member 20b is substantially at the same predetermined angle as the leaflet in the outflow direction, so that the support leading edge 21 'is substantially parallel and flush with the leaflet outer surface 46a.

[0076] The apex 21 of the distal end of the projection is located outside this orthogonal plane when it coincides with the trailing edge 28 of the annular support 12. That is, 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 comprise a lower face (i.e., a leading edge) parallel to the central portion 46 of the leaflet in the closed position.

[0077] refer to Fig.17 In the open position, the outer surface 46a of the leaflet is close to the apex 21. At the same time, the bend at or near the leading edge 42 of the leaflet contacts the inner surface of the apex 18 of the lower support member 16a, 16b (see also Fig.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 being on the surface adjacent to the recess 32. There is a gap with the apex 21 to avoid 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 abut against the support area 54 ( Fig.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, and the distance d2 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 provides an advantage over WO2008152224 in 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 is transformed from a closed configuration to an open configuration and avoids the leading edge of the leaflets abutting against the inner surface of the annular support, thereby causing undesirable reaction forces. Fig.24 and 25 , the upper supporting member (in Fig. 22 The reaction of the flap 40 (of which 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 resultant force on the flap 40 is almost zero, which significantly reduces the wear of the flap.

[0079] In contrast, reference Fig.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 may lead to premature wear of the leaflet. Fig.26 and 27 It can also be appreciated that the greater the deviation between the opening pressure and the reaction at the leading edge, the greater the reaction at the trailing edge will be. As a result, this specific function of the upper support member 20a becomes more important the closer the leaflet approaches the closed position.

[0080] To avoid the risk of jamming with other members holding the open position, in particular the guide surface 32 and the lower support members 16a, 16b, there may be a functional gap between the upper support members 20a, 20b and the outer surface 46a of the leaflet in the open position. This arrangement also allows a wider choice of leaflet materials, for example by using a material that is a little more sensitive to wear but has 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. 1 , 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 means for guiding the rotation of each leaflet define Fig. 22 and is located completely outside the corresponding leaflet, between the latter and the annular support 12.

[0082] In operation, the heart valve 10 is in the closed position at certain times. Figure 2 , 4 , 5, 8, and 13. The leaflets 40 converge together at the trailing edge 44, and the leading edge 42 of the leaflets 40 is flush with the inner wall 14 to provide a reliable seal to prevent blood backflow. 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 supporting the two lower support members 16a, 16b of each leaflet 40. Specifically, the apex 18 support area supports the inner surface 46b support area to prevent further movement of the leaflets. The lower support members 16a, 16b are located between the end portions 49a, 49b of the leaflets 40, and the lower support area 52 is set a predetermined distance inward from the leading edge 42 of the leaflets. In addition, the central support member 34 also supports the leaflet wings 48a, 48b. Refer to Fig.13 , the leading edge 42 of the leaflet abuts the proximal end of the guide surface 17. Since the lower support area 52 (between the apex 18 and the inner surface 46b) is away from the leading edge 42, wear on the leading edge 42 is reduced. There is a small gap 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, as shown in FIG. Fig.16 As shown in FIG. 4 , the outer surface 46a contacts the supporting front edge of the upper supporting members 20a, 20b. Fig.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, wherein the winglets 48a, 48b are guided by the recess 32 of the guide extension 30. The upper support area 54 is retreated 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 leaflets is guided by the guide surface 17 of the lower support members 16a, 16b. When the inner surface 46b of the leaflets contacts the apex 18, the movement of the leaflets stops.

[0085] Note that in the illustrated embodiment, there are three leaflets 40 and three guide extensions 30. In addition, 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] The applicant has found that according to the valve structure described in WO2008152224, as the leaflets rotate at the beginning of heart contraction, the leading edges of the two winglets of each leaflet slide against the inner peripheral surface of the annular support. Fig. 20 The constant contact between the leading edge of the annular support and the inner circumferential wall can produce flow recirculation in the obstructed area behind the valve leaflet, which can promote platelet aggregation and thrombus formation. Fig. 20 A partial cross-sectional view of the mechanical prosthetic heart valve disclosed in WO2008152224 is depicted on a plane perpendicular to the longitudinal axis of the annular support.

[0087] according to Fig.11 , 12 and 22, the lateral winglets 48a, 48b of each leaflet 40 ( Fig.12 ) has been determined so that the leading edge 42 and the outer surface of each leaflet 40 are at least 0.2 mm, preferably at least 0.3 mm, or 0.4 mm or even 0.5 mm away from the inner peripheral wall, which is 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) Fig.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. 22 Advantageously, the contact area of ​​the leaflets in the open position is smaller than that at the two end portions 49a, 49b ( Fig.11 and 12 ), i.e., less than 7.5% at each end portion 49a, 49b. In a preferred embodiment, this contact area of ​​the leaflet is less than 10% of the width W of the leaflet 40, i.e., less than 5% at each end portion 49a, 49b of the leaflet, preferably less than 7.5% of the width W of the leaflet 40, i.e., less than 3.75% at each end portion 49a, 49b of the leaflet, and even more preferably less than 5% of the width W of the leaflet 40, i.e., less than 2.5% at each end portion 49a, 49b of the leaflet, as shown in FIG. Fig. 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 FIGS. 1 and 12 , the distance L between the outer surface 46a of each leaflet 40 in the open position and the inner peripheral wall 14 of the annular support 12 is at least equal to 5% of the diameter of the annular support at the symmetry plane Z of the leaflet.

[0090] like Fig. 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. 1 , the leaflets 40 are configured in an open position to form a substantially triangular shape with rounded corners when arranged in the support member 12. The 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 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 member 12. In addition, as shown in FIG. Fig. 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] In addition, the curved proximal portion 43 is configured to start at the end of the recess so that the winglet 48 immediately turns sharply away from the inner wall 14 of the support 12, thereby forming a gap 50 between the outer surface 47 of the proximal portion 43 and the inner wall 14 of the support 12, and the gap 50 forms a channel through which blood can flow. Therefore, 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. In addition, the straight central portion 46 also minimizes interference with blood flow. Therefore, the configuration of the leaflet 40, such as the proximal portion 49 is located at the extension 30 and immediately bends inward to the next adjacent extension 30 in a linear manner, provides a widened gap 50 or channel between the leaflet 40 and the inner wall 14. In one embodiment, the distal portion 41 may also be bent inwardly to further widen the gap 50 just to the side of the extension 30 .

[0093] like Figure 3 As further shown in FIG. 4 , the center of the central portion 46 is the maximum distance between the leaflets 40 and the inner wall 14. The lower support or support members 16a, 16a are located at the inner wall 14 at the outermost portion of the central portion 46, adjacent to the curved proximal portion 43 of the winglet 48, to provide sufficient support when the leaflets 40 enter the closed position. The upper support members 20a, 20b can be positioned closer together at the central portion 46.

[0094] When the heart valve 10 is transformed from a closed configuration into an open configuration, 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. 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 that places the leaflet a little further downstream relative to the inner peripheral wall 14 in the open position. In particular, in the open position, 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 that places the leaflet a little further downstream relative to the inner peripheral wall 14 ... in the open position. In particular, in the open position, 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 that places Fig.19 , 21 The size of each flow channel 50 illustrated in FIGS. 22 and 23 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 plaque aggregation.

[0095] In contrast, the heart valve according to WO2008152224 has no flow channel at the level of the 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 is transformed from the closed configuration to the open configuration, as shown in FIG. Fig.23 This is mainly due to the contact area of ​​the leaflets, which is about 20% of the total width of the leaflets, that is, 10% at each end of the leaflets, as shown in Figure 2. Fig.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 invention, there are a variety of materials that can be used. For the annular support, for example, a biocompatible metal is selected, such as titanium or stellite. Solid carbon, or a carbon coating on graphite, can also be used.

[0097] The leaflets themselves are also rigid and can be made of a biocompatible material, such as monolithic carbon, or graphite with a pyrolytic carbon coating. The leaflets can also be made of a biocompatible synthetic polymer that also has wear resistance comparable to that of pyrolytic carbon. Thus, a material such as "PEEK" (which stands for polyetheretherketone) has a low density of approximately 1.3 and is particularly suitable for making the leaflets. This material can be reinforced with carbon to increase the wear resistance of the leaflets.

[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 a material for the manufacture of the leaflets and of pyrolytic carbon for the support or even of pyrolytic carbon for both the leaflets and the support.

[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 profiled, square, rectangular, triangular, linear, curved, curvature, circular, parallel, vertical, 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 appreciated that the present invention may be described in other ways without those geometric, relational, directional, or positioning terms. In addition, geometric or relational terms may not be accurate. For example, a wall or surface may not be completely flat, vertical, or parallel to each other, but is still considered to be substantially vertical or parallel due to, for example, the roughness of the surface, the tolerances allowed in manufacturing, and the like. Moreover, other suitable geometric shapes and relationships may be provided without departing from the scope of the appended claims.

[0100] Reference numerals list

[0101] Mechanical heart valve10

[0102] Ring 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 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 (40) arranged in such a manner that each of them can perform a rotational movement about an axis of rotation 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, 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 the blood from flowing back through the main orifice, Each leaflet 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 the 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 the number of leaflets (40), the extensions (30) extending axially from one of the opposing edges, the annular support (12) further comprising: at least one lower support member (16a, 16b) for each leaflet on the inner peripheral wall (14), the lower support member (16a, 16b) being located between two of the extensions (30) and being designed to contact against the corresponding leaflet when the valve (10) is in the closed configuration; and two upper support members (20a, 20b) for each leaflet, It is characterized in that The two upper support members (20a, 20b) each include a distal end, each distal end being designed to abut against a support area (54) of the outer surface (46a) of the leaflet (40), wherein a distance (d2) at which the center of the support area (54) is set back from the leading edge (42) of the leaflet (40) is greater than a thickness (t2) of the leaflet at the center of the support area.

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

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 the support area (54) is greater than the thickness (t2) of the leaflet (40) at the support area.

4. The mechanical artificial heart valve (10) according to claim 1, wherein: Each of the two upper support members (20a, 20b) extends inward from the inner peripheral wall (14) and has a proximal end, a middle portion and a distal end having an apex (21), and when the heart valve is in the closed structure, the middle portion extending from the proximal end is inclined at a predetermined angle in the flow direction to be parallel to the outer surface (46a) of the leaflet (40), wherein when the leaflet moves from the closed structure to the open structure, the outer surface (46a) of the leaflet contacts the leading edge (21') of each of the upper support members (20a, 20b) and pivots around the apex (21) of the upper support member (20) to rotate the leaflet (40) to the open structure.

5. The mechanical artificial heart valve (10) according to claim 4, wherein: The apexes (21) of the two upper support members (20a, 20b) are designed to abut against the support area during at least 20% of the opening travel of the leaflets as the valve transitions from a fully closed configuration to a fully open configuration.

6. The mechanical artificial heart valve (10) according to claim 5, wherein: Each apex (21) of the two upper support members (20a, 20b) is designed to abut against the support area during at least 50% of the opening stroke of the leaflets as the valve transitions from a fully closed configuration to a fully open configuration.

7. The mechanical artificial heart valve (10) according to claim 4, wherein: The leading edge (21') of each of the upper support members (20a, 20b) is linear.

8. The mechanical artificial heart valve (10) according to claim 1, wherein: The valve comprises exactly two lower support members (16a, 16b) per leaflet (40).

9. The mechanical artificial heart valve (10) according to claim 1, wherein: In a plane perpendicular to the longitudinal axis (X) of the valve, the axis of rotation 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).

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

11. The mechanical artificial heart valve (10) according to claim 1, wherein: The outer surface (46a) of each leaflet 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 of the leaflet.

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