WO2012035279A1

WO2012035279A1 - Implant designed to be placed in an auriculo-ventricular blood passage

Info

Publication number: WO2012035279A1
Application number: PCT/FR2011/052150
Authority: WO
Inventors: Doron Carmi; Marcel Peltier
Original assignee: Centre Hospitalier Régional Universitaire D'amiens
Priority date: 2010-09-17
Filing date: 2011-09-19
Publication date: 2012-03-22
Also published as: FR2964855A1; FR2964855B1

Abstract

The implant is designed to be placed in an auriculo-ventricular blood passage of a human or animal heart. The implant includes an endoprosthesis (14), defining a substantially annular blood passage, and anchoring means, comprising atrial anchoring means (20) and ventricular anchoring means (22) designed to clamp therebetween the leaflets of a natural mitral heart valve. The atrial (20) and ventricular (22) anchoring means can deform between a compacted configuration, for the placement of the implant (12), and a deployed configuration, allowing the implant (12) to be anchored in the heart, in which configuration the atrial (20) and ventricular (22) anchoring means are elastically returned.

Description

Implant intended to be placed in an auricuio-ventricular blood passage.

The present invention relates to the field of cardiac valve implants.

More particularly, the invention relates to an implant for placement in an atrioventricular blood passage of a human or animal heart.

During systole, the passage of blood between the left atrium and the left ventricle of the heart is interrupted by the closure of a heart valve of a mitral apparatus.

The mitral apparatus includes a mitral ring, two valvular leaflets connected to this ring, and a subvalvular apparatus with ropes and pillars. Among the two leaves, we distinguish the anterior leaflet or large mitral valve, and the posterior leaflet, or small mitral valve.

The connecting part of the ring with the large valve is fibrous whereas the connecting part of the ring with the small valve is muscular. The circumference of the mitral annulus is 90 to 110 millimeters in the case of a normal adult heart. The small valve is larger than the large valve. The small and large valves are connected to the ventricular wall by the ropes. themselves connected to the pillars.

In diastole, the two sheets retract to release the passage between the left atrium and ventricle.

In systole, ventricular contraction causes a sudden rise in left intra-ventricular pressure causing the ejection of blood through the aortic valve. Simultaneously, the contraction of the pillars and the tensioning of the ropes cause the junction of the sheets between them so as to isolate the left atrial and ventricular cavities.

The size of the mimate ring varies during the cardiac cycle so as to be maximal in diastole and mitral in systole (the circumference of the mitral annulus is 30 to 110 millimeters in the case of a normal adult heart) . The contraction of the mitral annulus between diastole and systole is not homogeneous throughout the perimeter of the mitral annulus. Indeed, this contraction is carried out essentially on the muscular part of the ring. This results in a change of shape of the mitral annulus which is slightly rounded in diastole and relatively elliptical in systole.

However, some heart valve diseases change the normal shape of the ring, which can lead, in the most severe cases, to the need for cardiac surgery.

It has therefore been proposed in the state of the art a mitral implant capable of remedying such pathologies.

A mitral implant must withstand the left ventricular systolic pressure and to adapt to the particular anatomy of the mitral annulus, in particular to its fibrous and muscular nature, its dimensions and its geometry which vary from one individual to another and during the cardiac cycle.

In addition, the mitral implant should not extend too far into the left ventricular flushing chamber (located near the large mitral valve) at the risk of disrupting blood flow through the aortic orifice.

Different implants have been proposed in the state of. technique that do not always give satisfaction.

Thus, the operation of certain implants is hampered by the strings of the subvalvular apparatus. Other implants present risks of obstruction of the left ventricular hunting chamber. Other implants still have a form that adapts badly to the anatomy; particular of the left atrioventricular orifice and thus creating leakage defects. This is the case, in particular, of certain implants comprising an elastically deformable endoprosthesis radially, usually called stent, whose circular shape does not fit properly to the anatomy of the left atrioventricular orifice.

WO 2006/063537 has proposed an implant for placement in an atrioventricular blood passage of a human or animal heart. This implant, adapted to the mitral passage, comprises an endoprosthesis, forming a substantially annular blood passage, provided with a valve. This implant also comprises fastening means in the heart connected to the stent. These attachment means comprise a skirt surrounding the stent intended to be sutured on the native mitral annulus, WO 2008/063537 also proposes to suture the skirt to parts of the leaflets or to ropes.

However, the attachment means of the implant proposed in WO 2008/063537 are relatively difficult to implement. In addition, the placement of this implant requires the removal of at least a portion of sheets.

US 2008/0221672 has proposed an implant intended to be placed in a mitral passage. This implant is moored in the mitral passage using metal rings deployed throughout the atrial cavity, These rings are relatively bulky because it is necessary to use several to ensure a solid docking of the implant susceptible to resist the systolic pressure (closed mitral valve),

The aim of the invention is to propose a valvular implant intended to be placed in an atrioventricular blood passage, in particular a mitral passage whose positioning and attachment in the heart can be achieved in a safe and effective manner, while adapting as much as possible to the blood pressure concerned and anatomical variations of the blood passage.

For this purpose, the subject of the invention is an implant intended to be placed in an auricular-ventricular blood passage of a human or animal heart, of the type comprising:

an endoprosthesis delimiting a substantially annular blood passage, and

- Fastening means of the implant in the heart connected to the stent, characterized in that the attachment means comprise atrial attachment means and ventricular attachment means for gripping the sheets of paper. a native mitral valve of the heart,

the atrial and ventricular attachment means being deformable between a compacted configuration, for implant placement, and an expanded configuration, allowing the attachment of the implant in the heart, in which the atrial attachment means and ventricles are recalled elastically,

The implant according to the invention makes it possible to preserve the leaflets of the native mitral valve of the heart, without the risk that the native leaflets obstruct the left ventricular hunting chamber. Indeed, the native sheets are clamped between the atrial attachment means and the ventricular attachment means, the front sheet being held in a closed position not dangerous.

Furthermore, the atrial and ventricular attachment means being resiliently biased towards their deployed configuration, the attachment of the implant in the atrioventricular blood passage is done automatically by elastic compression of the implant on the various native structures which surround.

Finally, the implant according to the invention, pinching the native leaflets Si is naturally linked to the movements of these leaflets which reduces its mechanical fatigue compared to an implant fixed on the native mitral ring.

The implant seftsn the invention can advantageously be implemented by the aplcale way in accordance with a conventional implantation method such as that commonly used for the establishment of heart valves in the aortic position. Note that according to this conventional method, access to the tip of the heart through a mini-thoracotomy that does not require extra corporeal circulation.

According to other optional features of the invention:

the atrial attachment means comprise flexible atrial arms distributed substantially circumferentially around the endoprosthesis, each atrial arm:

1. extending substantially parallel to a diametral plane of the blood passage delimited by the stent,

2, having a connecting end with this stent and a free end intended to bear against an atria cavity wall of the heart, and

3, ethanol deformable between a substantially axial configuration, for the implementation of the implant, and a substantially radial configuration, for the attachment of the implant in the heart, wherein the atrial arm is elastically biased;

the atrial arms carry a flexible waterproofing membrane, for example a membrane of synthetic material designated by the Dacron® trademark;

each atrial arm has a general shape at least partially curved substantially parallel to a diametral plane of the blood passage delimited by the stent, the curvature of the atrial arm being oriented opposite the direction of elastic return of the atrial arm, the curvature the atrial arm preferably moving towards the free end of this atrial arm so as to give this free end a general shape of a loop, and / or preferably evolving towards the connecting end of this arm, atrial so as to confer at this end of connection a general form of loop;

at least one atrial arm comprises means for gripping an atrial surface of a native rhthral leaflet,

in the deployed configuration of the implant, the atrial arms form a substantially conical beam converging in the direction of a blood flow intended to pass through the implant;

the atrial arms are made of shape-memory material, for example made of nickel-titanium alloy such as nitinol, or of an elastic material containing, for example, steel, more particularly spring steel;

the ventricular attachment means comprise ventricular arms distributed substantially circumferentially around the endoprosthesis, each ventricular arm:

2. having a connecting end with this ehdoprosthesis and a free end intended to bear on a ventricular leaf face and / or on a ventricular cavity wall of the heart and

3. having a helical general spring shape so as to be deformable between a compressed configuration for implant placement, and an elongated latching configuration of the implant in the heart, wherein the ventricular arm is recalled elastically;

the free end of each ventricular arm is provided with a destined head, on the one hand, to promote your penetration of this ventricular arm through the binding lines of sheets of a native mitral valve and, secondly, to allow support and attachment to the ventricular cavity wall.

the ventricular arms have different lengths between them to take account of the specific anatomy of the ventricular side of a left atrioventricular orifice of the heart;

the ventricular arms are made of a shape-memory material, for example a nickel-titanium alloy such as nitinol or an elastic material containing, for example, steel, more particularly spring steel;

at least one atrial arm has a cross section in general shape of concavity groove open towards the elastic return direction of this atrial arm, so that, since the Implant is considered in the extended attachment configuration, the relative positions of this atrial arm section gutter and a corresponding ventricular arm, promotes the interlocking of the ventricular arm in the atrial arm section gutter;

the endoprosthesis is radially deformable between a contracted configuration and an expanded configuration, in which it is resiliently biased, this stent comprises a stent body and a valve prosthesis preferably constituted by a bioprosthesis;

the implant comprises at least one wire bond connected to the endoprosthesis, for example a material designated by the Gore-Tex® brand, intended for attaching the implant to the tip of the heart.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings in which:

FIG 1 is a schematic perspective view of an implant according to the invention, only part of the atrial and ventricular attachment means being shown;

- Figure 2 is a view along the arrow II of Figure 1, reduced scale with respect to this Figure 1;

FIG 3 is a view along the arrow II I of Figure 1, reduced scale with respect to this Figure 1;

FIGS. 4 and 5 are schematic views of the implant according to the invention during two successive steps of placing the implant in an atrioventricular blood passage;

FIG. 6 is a detailed view of the circled portion VI in FIG. 5; on an enlarged scale with respect to this figure5; FIGS. 7 and 8 are schematic views of the implant according to the invention during two other successive steps of placing the implant in the atrioventricular blood passage;

FIG 9 is a detail view of the circled portion IX in Figure 6;

FIG. 10 is a detail view, in perspective, of the circled portion X of FIG. 9, on an enlarged scale with respect to this FIG. 9;

FIG 11 is a schematic view of the implant according to the invention showing a final step of anchoring the implant in the atrioventricular blood passage.

FIGS. 1 to 3 show an implant according to the invention designated by the general reference 12, This implant 12 is intended to be placed in an atrioventricular blood passage of a human or animal heart, such as a passage mitraJ.

The implant 12 comprises a stent 14 forming a substantially annular blood passage. The stent 14 is elastically deformable radially between an expanded configuration, as shown in Figures 1 and 3, and a contracted configuration opposing its elastic return force.

The stent: 14 comprises a stent body 16 and a valve prosthesis 18. The stent 16 comprises a conventional wire mesh, elastically deformable between contracted and expanded configurations of the stent 14. Where appropriate, the wire mesh is covered a membrane made of synthetic material usually designated by the Dacron ® brand. The valve prosthesis 18 is preferably constituted by a conventional bio-prosthesis.

Implant 12 also comprises means for fastening this implant in the heart connected to stent 14.

These attachment means comprise atrial attachment means 20 and ventricular attachment means 22 intended to clamp between them the sheets of a native mitral valve of the heart. The atrial and ventricular fastening means 22 are deformable between a compacted configuration, as shown in FIG. 4, for the placement of the implant 12, and an expanded configuration, as represented in FIGS. 1 and 8. , for the attachment of the implant 12 in the heart.

The atrial and ventricular catching means 22 are resiliently biased towards their deployed configuration,

With particular reference to Figures 1 and 2, we see that the atrial attachment means 20 comprise flexible atrial arms 24 distributed substantially circumferentially around the body 16 of the stent. We note that only some atrial arms 24 are shown in Figure 1.

Each atrial arm 24 extends substantially parallel to a diametral plane of the blood passage defined by the stent 14,

The atrial arms 24 comprise an end 24A of connection with the body 16 of the stent 14 and a free end 24B intended to bear against an atrial cavity wall PA, as shown in FIGS. 5, 7 and 8. .

The atrial arms 24 are deformable between a substantially axial configuration for the placement of the implant 12, as shown in FIG. 4, and a radial configuration for the attachment of the implant 12 in the heart, as represented in FIGS. 1 and 8. The atrial arms 24 are resiliently biased towards their radial attachment configuration of the implant 12.

Referring to Figure 2, we see that the atrial arms 24 carry a flexible sealing membrane 26, for example Dacron ®. The atrial arms 24 and the membrane 26 ensure the sealing of the implant by automatically adapting to various anatomical configurations that may evolve particularly with the cardiac cycle. Indeed, the membrane 26 associated with the flexible atrial arms 24 forms an automatically deployable skirt, capable of marrying the shapes of the surrounding native sheets and walls by ensuring an effective etanrhéité, in particular by closing the space between the mltral ring and the The size of the blood passage delimited by the stent 16 is indeed smaller than the size of the native mitral passage, which is not a problem in view of the atrioventricular blood flow considered,

Each atrial arm 24 has, preferably, a general shape at least partly curved substantially parallel to a diametral plane of the blood passage delimited by the serit 16 (see in particular Figure 4). The curvature of the atrial arms 24 is oriented opposite to the elastic return direction of these bTas 24.

Also preferably, the curvature of the atrial arms 24 evolves towards their free end 24B so as to give this free end 24B a general loop shape avoiding any aggression of the surrounding wall of the atrial cavity.

More preferably, the curvature of the atrial arms 24 evolves towards their connecting end 24A so as to give this connecting end 24A a general loop shape.

The ends 24A, 24B of the loop-shaped atrial arms 24 optimize the contact of these arms 24 with the native structures by promoting the elastic adaptation of the shape of these arms 24 to the deformation of the mitral annulus during the cardiac cycle. . In order to promote the connection between the atrial arms 24 and the leaflets of a native mitral valve, at least some atrial arms 24 comprise elements 28 for gripping an atrial surface of these leaflets.

It will be noted with particular reference to FIGS. 1 and 8 that when the implant 12 is in its deployed configuration, the atrial arms 24 form a conical beam converging in the direction of the blood flow intended to pass through this Implant 12. This disposition favors the resistance the attachment of the implant 12 to the left ventricular systolic pressure,

Preferably, the atrial arms 24 are made of a shape memory material, for example a nickel-titanium alloy such as nilinol, or an elastic material containing, for example, steel, more particularly spring steel,

The connecting ends 24A of the atrial arms 24 are connected to the stent 16, for example by interlacing with the metal mesh forming the stent 16,

Referring more particularly to FIGS. 1 and 3, it can be seen that the ventricular attachment means 22 comprise ventricular arms 30 distributed substantially circumferentially around the stent 16. Each ventricular arm 30 extends substantially parallel to a diametral plane of the blood passage delimited by the stent 16 of the stent,

The ventricular arms 30 each comprise an end 30A for connection with the stent 16 and a free end 30B intended to bear on a PV wall of the ventricular cavity of the heart.

The ventricular arms 30 are arranged on the stent 16 upstream of the atrial arms by considering the direction of the atrioventricular blood flow.

The ventricular arms 30 each have a helical general spring shape so as to be deformable between a compressed configuration, as shown in particular in Figures 4 and 5, for the establishment of the implant 12, and an elongated configuration, as shown in particular in Figures 1 and 3, for the attachment of the implant 12, the ventricular arms 30 are resiliently biased to their extended attachment position of the Implant 12.

Preferably, the free end 30B of the ventricular arms 30 is provided with a head 32 intended, on the one hand, to promote the penetration of the ventricular arms 30 through the binding lines of the leaflets of a native mitral valve and, on the other hand, to allow the support and hangup of these ventricular arms 30 on a ventricular leaflet face and / or the PV wall of the ventricular cavity.

The penetration of the ventricular arms 30 through the ropes promotes the strength of the attachment of the implant 12.

Referring more particularly to Figure 3, we see that the arms The ventricles 30 have different lengths to each other to account for the specific anatomy of the ventricular side of a left atrioventricular port of the heart. In particular, the ventricular arms 30 may be shorter at the root aortic.

Preferably, the ventricular arms 30 are made of a shape memory material, for example a nickel-titanium alloy such as nitinol, or an elastic material containing, for example, steel, more particularly spring steel.

Each ventricular arm 30 corresponds to an atrial arm 24 having an angular position around the stent 16 substantially coinciding with that of the corresponding ventricular arm 30.

With particular reference to FIG. 10, it should be noted that at least one atrial arm 24, preferably each atrial arm 24 associated with a ventricular arm 30, has a transverse sectton in the general shape of a gutter with an open concavity towards the direction of resilient return of this atrial arm 24. Thus, considering the implant 12 in the deployed configuration, as shown in Figures 1 and 8 to 10, the relative position of an atrial arm 24 gutter section relative to a corresponding ventricular arm 30 promotes the engagement of this ventricular arm 30 in the atrial arm 24 section gutter.

Since the atrial arms 24 form a tapered beam converging in the direction of the blood flow to pass through the implant 12, the ventricular arms 30 leaning against the atrial arms 24 tend, under the effect of the systolic pressure, to compress and therefore increase the resistance of the attachment of the implant 12.

In FIG. 10, there is shown a leaflet F of a native mitral valve sandwiched between the atrial arm 24 with a gutter section and the corresponding ventricular arm 30.

The main steps related to the invention of a method for placing an implant 12 in an atrioventricular blood passage, such as a mitral passage, will be described below with reference to FIGS. 4 to 10.

First, the tip of the pericardium is reached by performing an anterior mini thoracotomy and a reinforced double suture is made on the tip of the left ventricle.

Then, in a manner known per se, is placed in an atrioventricular blood passage 34 as shown in Figure 4, the open end of a conventional sheath 36 so that this end opens into the atrial cavity.

The sheath 36 contains the implant 12 in a compacted configuration as well as a Conventional Balloon Catheter (not shown), The compacted implant 12 and the balloon catheter are carried by a conventional guide 38.

The guide 3S is positioned so that the atrial arms 24, still retained in the sheath 36, are positioned in the atrial cavity, as shown in FIG. 4.

By appropriate displacements of the sheath 36, the atrial arms 24 are released from the sheath, so that the latter are resiliently biased back into their deployed configuration, as shown in FIGS. 5 and 6. The atrial arms 24 are supported by the RA wall of the atrial cavity and on the F leaflets of the native mitral valve. The gripping means 28 cooperate with the sheets F so as to secure the atrial arms 24 with these sheets F, as shown in FIG. 6,

Then, while the ventricular arms 30, still compressed in the sheath 36, are positioned in the ventricular cavity, as shown in FIG. 5, sheath 36 is displaced so as to release these ventricular arms 30. the latter deform automatically in their elongated configuration as shown in FIG. 7.

The ventricular arms 30 rest on the PV wall of the ventricular cavity and the F leaves of the native mitral valve. The heads 32 of the ventricular arms 30 facilitate the penetration of the ventricular arms 30 through the strings (not shown) of the native mitral valve. Furthermore, the gutter section of the atrial arms 24 promotes the guidance of the ventricular arms 30 against the atrial arms. 24,

Then, in a conventional manner, the balloon is inflated so as to deploy the stent 16 in its expanded configuration as shown in FIG. 8, preferably the implant 12 comprises at least one link 40 connected to a ventricular end of the balloon. endoprosthesis 14, for example three links 40 as shown in FIGS. 8 and 11. These links 40, for example material designated by Gore-Tex ® mark, are intended for attachment of the implant 12 at the tip of the heart PC,

The links 40, temporarily also connected to the guide 38, are stretched by displacement of this guide 38 after deployment of the stent 16 in its expanded configuration as shown in FIG. 8.

The attachment of the links 40 to the tip of the heart is made in known manner by means of an anchor buttonhole 42,

Claims

1. An implant (12) for placement in an atrioventricular blood passage (34) of a human or animal heart, of the type comprising:

an endoprosthesis (14) delimiting a substantially annular blood passage, and

-means (20,22) for fastening the implant in the heart connected to the stent (14)

characterized in that (the attachment means comprise atrial attachment means (20) and ventricular attachment means (22) intended to clamp between them the sheets (F) of a native mitral valve of the heart,

the atrial (20) and ventricular locking means (22) being defibmable between a compacted configuration, for the placement of the implant (12), and an expanded configuration, allowing the attachment of the implant (12) in the heart, in which the atrial (20) and ventricular (22) attachment means are resiliently biased.

An implant according to claim 1, wherein the atrial catching means (20) comprises flexible atrial arms (24) distributed substantially circumferentially around the stent (14), each atrial arm (24):

extending substantially parallel to a diametral plane of the blood passage delimited by the stent (14),

having an end (24A) of connection with this endoprosthesis (14) and a free end (24B) intended to rest on an atrial cavity wall (PA) of the heart, and

being deformable between a substantially axial configuration, for the placement of the implant (12), and a substantially radial configuration, for hanging up the Implant (1 2) in the heart, in which the atrial arm (24) is recalled elastically.

3. Implant according to claim 2, in which the atrial arms (24) carry a flexible sealing membrane (26), for example a membrane of synthetic material designated by the Dacron® brand,

The implant of claim 2 or 3, wherein each atrial arm (24) is generally at least partially curved substantially parallel to a diametral plane of the blood passage defined by the stent (14),

the curvature of the atrial arm (24) being oriented opposite to the direction of elastic return of the atrial arm (24),

the curvature of the atrial arm (24) preferably evolving towards the free end (24B) of this atrial arm so as to give this free end (24B) a general shape of a loop, and / or preferably evolving towards the connecting end (24A) of this atrial arm so as to confer on this connecting end ( 24A) a general form of loop.

An implant according to any one of claims 2 to 4, wherein at least one atrial arm (24) comprises means (28) for gripping an atrial surface of native mitral valve leaflet.

An implant according to any one of claims 2 to 5, wherein, in the expanded configuration of the implant (12), the atrial arms (24) form a substantially conical bundle converging in the direction of a blood flow for cross the Implant (12),

An implant according to any one of claims 2 to 6, wherein the atrial arms (24) are of shape memory material, for example nickel-titanium alloy such as nltinol, or an elastic material containing by example of steel, more particularly of spring steel.

8. Implant according to any one of the preceding claims, wherein the ventricular attachment means (22) comprise ventricular arms (30) distributed substantially circumferentially around the stent (14), each ventricular arm (30):

comprising one end (30A) of connection with this endoprosthesis (14) and a free end (30B) intended to rest on a leaf ventricular faoe (F) and / or a wall (PV) of the ventricular cavity of the heart, and

having a generally helical spring-forming shape so as to be deformable between a compressed configuration for the implantation of the implant (12), and an elongate latching configuration of the implant (12) in the heart, in the the ventricular arm (30) is elastically biased

9. Implant according to claim 8, wherein the free end (30B) of each ventricular arm (30) is provided with a head (32) intended, on the one hand, to promote the penetration of this ventricular arm (30). ) through leaflet binding cords of a native mitral valve and, secondly, to allow support and attachment to the ventricular cavity wall (PV).

An implant according to claim 8 or 9, wherein the ventricular arms (30) have different lengths to each other to account for the specific anatomy of the ventricular side of a left atrioventricular port of the heart.

11. Implant according to any one of claims 8 to 10, wherein the ventricular arms (30) are of shape memory material, for example nickel-titanium alloy such as nitinol, or an elastic material containing by example of steel, more particularly of spring steel.

12. Implant according to claims 2 and 8 taken together, wherein at least one afrial arm (24) has a cross section in the general shape of concavity groove open to the direction of elastic return of the atrial arm (24), so that, since the implant is considered in the deployed attachment configuration, the relative positions of this atrial arm (24) with a gutter section and a corresponding ventricular arm (30) promote the interlocking of this ventricular arm (30). in the atrial arm (24) with gutter section.

An implant according to any one of the preceding claims, wherein the stent (14) is radially deformable between a contracted configuration and an expanded configuration, in which it is resiliently biased, the stent (14) comprising a stent body ( 16) and a valve prosthesis (18) preferably consisting of a bioprosthesis.

14. Implant according to any one of the preceding claims, comprising at least one wired link connected to the stent (14), for example material designated by the Gdre-Tex ® brand, intended for the attachment of the implant to the tip of the heart.