Patent Description:
The mitral valve lies between the left atrium and the left ventricle of the heart. Various diseases can affect the function of the mitral valve, including degenerative mitral valve disease and mitral valve prolapse. These diseases can cause mitral stenosis, in which the valve fails to open fully and thereby obstructs blood flow, and/or mitral insufficiency, in which the mitral valve is incompetent and blood flows passively in the wrong direction.

Many patients with heart disease, such as problems with the mitral valve, are intolerant of the trauma associated with open-heart surgery. Age or advanced illness may have impaired the patient's ability to recover from the injury of an open-heart procedure. Additionally, the high costs are associated with open-heart surgery and extra-corporeal perfusion can make such procedures prohibitive.

Patients in need of cardiac valve repair or cardiac valve replacement can be served by minimally invasive surgical techniques. In many minimally invasive procedures, small devices are manipulated within the patient's body under visualization from a live imaging source like ultrasound, fluoroscopy, or endoscopy. Minimally invasive cardiac procedures are inherently less traumatic than open procedures and may be performed without extra-corporeal perfusion, which carries a significant risk of procedural complications.

Minimally invasive aortic valve replacement devices, such as the Medtronic Corevalve or the Edwards Sapien, deliver aortic valve prostheses through small tubes which may be positioned within the heart through the aorta via the femoral artery or through the apex of the heart. However, current cardiac valve prostheses are not designed to function effectively within the mitral valve. Further, current cardiac valve prostheses delivered via a minimally invasive device are often difficult to place correctly within the native valve, difficult to match in size to the native valve, and difficult to retrieve and replace if initially placed incorrectly.

Accordingly, it is desirable to have a mitral valve replacement that solves some or all of these problems.

<CIT> discloses an apparatus for replacing a cardiac valve having at least two native valve leaflets includes an expandable support member with oppositely disposed first and second ends and a main body portion extending between the ends. The first and second ends respectively include a plurality of upper and lower wing members respectively having first and second magnetic components. The wing members extend from the main body portion and are spaced circumferentially thereabout. Secured within the main body portion is a prosthetic valve having at least two valve leaflets. The second end further includes at least two strut members spaced apart from each other and attached to at least one commissural section of the prosthetic valve. The magnetic components are magnetically attracted to one another so that, when the apparatus is placed in the valve annulus, the wing members are pulled toward one another to secure the prosthetic valve in the annulus.

<CIT> discloses am apparatus for endovascularly replacing a patient's heart valve, including: a delivery catheter having a diameter of <NUM> french or less; an expandable anchor disposed within the delivery catheter; and a replacement valve disposed within the delivery catheter. The invention also includes a method for endovascularly replacing a heart valve of a patient. In some embodiments the method includes the steps of: inserting a catheter having a diameter no more than <NUM> french into the patient; endovascularly delivering a replacement valve and an expandable anchor to a vicinity of the heart valve through the catheter; and deploying the anchor and the replacement valve.

<CIT> discloses a heart valve prosthesis including a supported valve including a biological valve portion mounted within a support structure. The supported valve is configured to provide for substantially unidirectional flow of blood through the supported valve. The supported valve has inflow and outflow ends that are spaced axially apart from each other. A fixation support member includes inflow and outflow portions. The inflow portion of the fixation support member extends from a radially inner contact surface of the fixation support member radially outwardly and axially in a direction of the inflow end of the supported valve. The outflow portion of the fixation support member extends from the radially inner contact surface radially outwardly and axially in a direction away from the inflow portion of the fixation support member. The radially inner contact surface is attached to a radially outer surface of the supported valve adjacent the inflow end of the supported valve. The supported valve and the fixation support member are deformable between a reduced cross-sectional dimension and an expanded cross-sectional dimension thereof.

<CIT> discloses an apparatus for adjusting the position and orientation of a medical device within a patient's body includes a distal portion, a body portion and a proximal portion. The distal portion has a lumen for receiving at least three control tubes. Each control tube houses a control wire that is attached to the medical device. The body portion is connected to the distal portion by a ball-and-socket joint and configured to receive at least one control wire. The proximal portion is rotatably and slidably attached to the body portion and configured to receive at least one control wire.

Aspects, embodiments and examples of the present disclosure which do not fall under the scope of the appended claims do not form part of the invention and are merely provided for illustrative purposes.

The novel features of the invention are set forth with particularity in the claims.

Described herein is a flexible, self-orienting cardiac valve prosthesis configured to be delivered through minimally invasive techniques. The prosthesis can include a proximal anchor (e.g., configured to be placed in the ventricle), a distal anchor (e.g., configured to be placed in the atrium), a central portion or column between the anchors, a plurality of struts extending distally (e.g., into the ventricle), and a plurality of leaflets attached to the struts. The prosthesis can be self-expanding, such as be made of super elastic nickel titanium (nitinol). In some embodiments, the prosthesis can be made of woven stranded nitinol.

The prosthesis described herein can be delivered to a cardiac valve orifice, such as the mitral valve, by using minimally invasive techniques to access cardiac valves through small incisions in the patient's body, passing the prosthesis through the apex of the heart, through the aorta via femoral artery access, through the aorta via an intercostal puncture, through the vena cava via femoral vein access, through the vena cava via jugular access, and through the venous system into the left heart via a transseptal puncture. The flexible prosthesis can be folded and compressed to fit within a delivery tube. The delivery tube can be used to position the prosthesis at the treatment site, and if necessary, re-sheath, reposition, and re-deploy the device.

During deployment, the distal anchor can be deployed first in a cardiac chamber, such as the ventricle, and retracted to a seated position against the valve orifice, such as the mitral valve orifice. Then the center column and proximal anchor may then be deployed in another cardiac chamber, such as the atrium, sandwiching the valve orifice securely between the anchors in opposing cardiac chambers.

Embodiments of the invention are designed to secure the valve prosthesis in the orifice by applying a radial force from the center column structure of the prosthesis outward against the cardiac orifice and by sandwiching the cardiac orifice between distal and proximal anchors that are larger in diameter than the orifice. Further engagement between the prosthesis and tissue may be added by securing small, curved wire hooks into the sub-structures of the valve prosthesis.

<FIG> show an exemplary embodiment of a valve prosthesis <NUM>. The valve prosthesis includes a proximal anchor <NUM>, a distal anchor <NUM>, and a central portion <NUM> therebetween. A central opening <NUM> extends through the center of the prosthesis <NUM>. The central portion <NUM> can substantially trace the perimeter of the central opening <NUM> while each anchor <NUM>, <NUM> can extend outwardly therefrom in an annular shape. The proximal anchor <NUM>, distal anchor <NUM>, and central portion <NUM> can be formed of wire, such as nitinol wire rope. Each anchor <NUM>,<NUM> can include a first outer frame <NUM>, <NUM> and a second outer frame <NUM>, <NUM>, respectively. In one embodiment, the proximal anchor <NUM> and distal anchor <NUM> can be substantially parallel to one another.

An exemplary proximal anchor <NUM> is shown in <FIG>. The first outer frame <NUM> can sit proximal to the second outer frame <NUM>, and the first outer frame <NUM> can sit in a plane substantially parallel to the plane of the second outer frame <NUM>. Further, each frame <NUM>, <NUM> can include a plurality of arcs <NUM>, <NUM> (which can also be referred to as arcuate portions, curved portions, or petals), such as between <NUM> and <NUM> or between <NUM> and <NUM> arcs, joined together at joints <NUM>, <NUM>, respectively. For example, outer frame <NUM> can include six arcs 111a,b,c,d,e,f while outer frame <NUM> can also include six arcs 211a,b,c,d,e,f. The arcs <NUM> of the outer frame <NUM> can be connected together, and the arcs <NUM> of the outer frame <NUM> can be connected together, so as to form a substantially circular outer perimeter for each of the frames <NUM>, <NUM>.

Each joint <NUM>, <NUM> between neighboring arcs <NUM> or <NUM> can be, for example, a crimp that crimps adjacent arcs (e.g., 111a and 111b) to one another. As shown in <FIG>, the outer frames <NUM>, <NUM> can be positioned relative to one another such that the arcs <NUM>, <NUM> are out of phase relative to one another. For example, the arcs <NUM> can be approximately <NUM> degrees out of phase relative to the arcs <NUM>. That is, the arcs <NUM> of the first outer frame <NUM> can overlap with the arcs <NUM> of the second outer frame <NUM> such that, for example, a single arc 111a of the first outer frame <NUM> overlaps with half of two underlying arcs 211f, 211a of the second outer frame <NUM>. In some embodiments, only some arcs are out of phase with one another while other arcs are in-phase with one another. The second outer frames <NUM>, <NUM> can likewise include arcs as described with respect to the first outer frame <NUM>, <NUM>.

As shown in <FIG> and <FIG>, the first outer frame <NUM>, <NUM> and the second outer frame <NUM>, <NUM> of each anchor <NUM>, <NUM> can be connected to one another through the central portion <NUM>. The central portion <NUM> can extend from the crimps <NUM>, <NUM> of the proximal anchor <NUM> to the corresponding crimps of the distal anchor <NUM>. The central portion <NUM> can include substructures or wire segments <NUM> that form a pattern, such as a hexagonal pattern (see <FIG>). For example, two wire segments 44a,b of the central portion <NUM> can extend at an angle from the crimp 16a (see <FIG>, <FIG>), such as to form an angle of approximately <NUM> degrees relative to one another. Each of the wire segments 44a,b can then meet adjacent wire segments within the central portion <NUM> (e.g., segment 44b meets segment 44c). The adjacent wire segments (e.g., 44b and 44c) can then be joined together at a joint <NUM> (e.g., joint 46a). The joint 46a can form a column substantially parallel to a central axis <NUM> of the prosthesis <NUM>. This pattern can extend throughout the entire prosthesis to form a number of joints <NUM>, such as twelve joints <NUM>. The joints <NUM> can not only fix the position of the outer frames of a single anchor together, but also fix the proximal and distal anchors <NUM>, <NUM> together. The hexagonal structure of the segments <NUM> and joints <NUM> can advantageously provide radial and vertical strength as well as stability to the prosthesis <NUM>.

In some embodiments (as shown in <FIG>), parts of the central portion <NUM> can be formed of the same wire or wire rope as the outer frames of the anchors <NUM>,<NUM> and/or the outer frames of the anchors <NUM>,<NUM> can be formed of the same wire or wire rope as one another. For example, two single strands of wire, such as two <NUM> (<NUM>-inch) long strands of wire, can be used to form the anchors <NUM>, <NUM> and the central portion <NUM>. As shown in <FIG> and <FIG>, a single strand <NUM> (darkened in the picture relative to the opposite strand <NUM> for clarity) can form an arc 111a (see <FIG>) of the first outer frame <NUM> of proximal anchor <NUM>, extend through a joint 16a to form wire segment 44b of the central portion <NUM>, extend through joint 46a to form wire segment 44d (see <FIG>), then form an arch of the second outer frame <NUM>, extend through another joint to form wire segment 44e (see <FIG>), extend around in a similar fashion to form wire segment 44f (see <FIG>), and continue winding in a similar fashion until all of the outer frames <NUM>, <NUM> have been formed from the single strand <NUM>. The ends of the strand <NUM> can then be attached to one another, such as through splicing crimps, butt joint crimps, welding, riveting, or weaving. The second strand <NUM> can be wound similarly to form the second outer frame <NUM> of the proximal anchor <NUM> and the first outer frame <NUM> of the distal anchor <NUM>.

By joining the first outer frame <NUM>, <NUM> to the second outer frame <NUM>, <NUM> of each anchor <NUM>, <NUM>, as described above, the arcs of each outer frame can be movable relative to one another. For example, the arc 111a can be movable relative to the arcs 211f, 211a that it overlaps (see <FIG>). That is, the outer perimeter of the arc 111a can flex along the central axis and/or translate relative to the arcs 211f, 211a (while the inner perimeter is fixed at the joints <NUM>).

Advantageously, the large arc structure of the anchors can provide flexibility and compliance for the portions of the prosthesis intended to be placed in the chambers of the heart. In contrast, in the stiffer tissue of the valve orifice, the hexagonal sub-structures of the central portion can provide higher radial stiffness and strength.

Further, by using wire rope, the prosthesis can advantageously be foldable and strong while the individual fibers, because they are small in diameter, can maintain resistance to fatigue and fracture. In some embodiments, the two frames of a single anchor can be formed of wire rope of opposite lays. For example, the wire of one frame (e.g. strand <NUM>) can be made of a rope twisted to the left while the wire of another frame (e.g. strand <NUM>) can be made of a rope twisted to the right. Using wires of opposite lays can allow the wires to compensate for one another as they compress, thereby maintaining relative positioning during expansion or contraction/folding of the device (as opposed to twisting of the entire device). Various possibilities for winding the wire rope are shown in <FIG>.

As shown in <FIG> and <FIG>, struts <NUM> can extend distally from the distal anchor <NUM> and/or the central portion <NUM> and be configured to hold leaflets (shown in <FIG>). The struts <NUM> can be formed, for example, of wire rope. Further, in one example, each strut <NUM> can include a plurality of wire components <NUM>, such as three wire components <NUM>. Each of the three wire components <NUM> of a single strut <NUM> can extend from neighboring joints <NUM> and come together at a joint <NUM>, thereby forming triangular struts <NUM>. In some embodiments, additional supporting structures, such as tubes, can be placed over or around the struts to increase the stiffness. The triangular struts <NUM> can provide vertical strength and lateral flexibility.

In one embodiment, there can be three struts <NUM> located approximately <NUM> degrees away from one another around the circumference of the prosthesis <NUM>. The joints <NUM> can be, for example, crimps. As shown in <FIG> and <FIG>, in one embodiment, the center strut member 55a of a three-strut support can be substantially straight and connected to two outside, curved strut members 55b, 55c to form a structure comprised of two substantially triangular sub-structures, each with the center member as a common triangle leg. This center member may be made of a thin element of material which provides strength in tension as the pressurized leaflets are pushed toward the center of the valve, while providing flexion in compression to allow the valve prosthesis to be folded for delivery and to allow the prosthesis to conform to tissue when placed within the heart.

The various crimps used for the joints of the prosthesis <NUM> may be made of a suitable implantable material, such as platinum, tantalum, or titanium. Further, in place of crimps, braids, weaves, or welding can be used.

Referring to <FIG>, the valve prosthesis <NUM> can include integral valve leaflets <NUM> attached, such as sewn, to the struts <NUM>. There can be three integral valve leaflets <NUM>, and the leaflets <NUM> can form a pressure actuated valve that provides uni-directional flow occlusion when the prosthesis <NUM> is implanted in a valve orifice. The leaflets can be constructed of bio-materials, such as bovine or porcine pericardium, or polymer materials.

In one embodiment (shown in <FIG>), the proximal anchor <NUM> can include a cover or skirt <NUM> thereon or therearound formed of a biomaterial or thin polymer material. The skirt <NUM> can advantageously help seal the prosthesis <NUM> against the cardiac tissue when implanted.

The prosthesis <NUM> can be configured to be placed in a cardiac valve orifice such that the central portion <NUM> lines the orifice while the proximal and distal anchors <NUM>, <NUM> sit within the chambers of the heart and pinch tissue of the orifice therebetween.

In some embodiments, the prosthesis <NUM> can be sized and configured for use in the mitral valve orifice (shown in <FIG>). Referring to <FIG>, to ensure that the prosthesis <NUM> fits properly within the valve, the diameter do of the central opening <NUM> can be greater than a length ℓ of the device when fully expanded. For example, the ratio do/ ℓ can be greater than or equal to <NUM>, such as greater than or equal to <NUM> or greater than or equal to <NUM>. Further, the ratio do/ ℓ can be less than <NUM>. In one embodiment, the diameter do is between <NUM> and <NUM>, such as approximately <NUM>. Further, in one embodiment, the length ℓ is less than or equal to <NUM>, or less than or equal to <NUM>, such as approximately <NUM>. Further, to ensure that the proximal and distal anchors have enough tissue to grab onto, a ratio of the outer diameter of the anchors, dT, to the length ℓ can be greater than or equal to <NUM>. In one embodiment, an outer diameter of anchors, dT, can be at least <NUM>, such as greater than or equal to <NUM>. Further, in one embodiment, the anchors can extend out at a radius ra of greater than <NUM>, such as approximately <NUM>. Finally, a ratio do to a length of the struts ℓs can be approximately <NUM> to <NUM>, such as <NUM>. A radio of do/ls within this range can advantageously ensure that there is enough leaflet material to allow the leaflets to oppose and seal under stress while maintaining a small enough length to fit properly within the valve. In one embodiment, the struts have a length ℓs of between <NUM> and <NUM>, such as approximately <NUM>. Further, ℓc can be approximately <NUM>-<NUM>, such as <NUM>.

In one exemplary embodiment, do is <NUM>, ra is <NUM>, ℓc is <NUM>, ℓs is <NUM>, dT is <NUM>, and ℓ <NUM> is <NUM>.

<FIG> show a closed delivery device <NUM> for delivery of a valve prosthesis <NUM>. The delivery device <NUM> can include an outer sheath <NUM> and a multi-lumen central longitudinal structure <NUM> extending therethrough. The valve prosthesis <NUM> is configured to fit over the central longitudinal structure <NUM> and within the sheath <NUM> so as to be fully encapsulated within the delivery device <NUM>. The lumens in the longitudinal structure <NUM> can be tubular structures <NUM> (see <FIG> and <FIG>). Each tubular structure <NUM> can include a side lumen <NUM> (see <FIG> and <FIG>) therein, i. e, an aperture disposed on a radial outer portion of the tubular wall. The tubular structures <NUM> can contain retention members <NUM> that bind the proximal anchor <NUM> of the valve prosthesis tightly to the longitudinal structure <NUM>. The retention members <NUM> can be made, for example, of a strong, flexible material such as nitinol, nitinol wire rope, or liquid crystal polymer fiber, such as Vectran®. There can be various numbers of retention wires and corresponding tubes <NUM> and lumens, such as between <NUM> and <NUM> or between <NUM> and <NUM> retention wires and corresponding tubes/lumens. In one embodiment, there are six retention wires and lumens. In another, there are twelve retention wires and lumens. The delivery device <NUM> includes a central lumen <NUM> running therethrough (i.e., through the central longitudinal structure <NUM>) configured to pass a standard cardiac guidewire <NUM>. The guidewire <NUM> may be used to provide a safe pathway for getting the device <NUM> to the anatomical target. The delivery device <NUM> further includes a tapered tip <NUM> to provide a gradual, atraumatic transition from the guidewire to the outer sheath <NUM> of the delivery device <NUM>.

In some embodiments, the delivery device <NUM> can be adapted to specific delivery paths and cardiac structures by being provided with pre-shaped bends in the outer sheath <NUM>. In some embodiments, the delivery device <NUM> may contain pull-wires integral with the outer wall that may be tensioned to articulate and bend the outer sheath <NUM>. The pull wires may terminate at the tip of the device to provide a bend starting at the distal tip or may terminate along the longitudinal shaft of the device to provide a more proximal bend location.

<FIG> show a multi-stage delivery system for a cardiac valve prosthesis (with the valve leaflets omitted from the drawings for clarity). <FIG> shows the delivery device <NUM> having a handle <NUM> connected thereto to control the delivery of a prosthesis loaded within the device.

<FIG> and <FIG> shows the prosthesis <NUM> partially deployed. That is, as the sheath <NUM> is pulled back with a lever <NUM> on the handle <NUM>, the distal anchor <NUM> (previously collapsed into the sheath <NUM> with the peaks of the arcs extending distally) pops open. The proximal anchor <NUM>, in turn, can remain connected to the delivery device <NUM> via the retention wires <NUM>. That is, the retention wires <NUM> can pass through the multi-lumen central structure <NUM>, through the arcs of the outer frame <NUM>, <NUM> at apertures <NUM>, and back into lumens of the structure <NUM>. Referring to <FIG> and <FIG>, in one embodiment, the proximal anchor <NUM> can be connected to the retention wires <NUM> such that neighboring arcs 111a, 211a of the proximal anchor <NUM> extend over neighboring retention wires 19a, 19b. In other embodiments (as shown in <FIG>), two neighboring arcs 111a, 211a can extend over a single retention wire 19a. Referring back to <FIG> and <FIG>, as the retention wires <NUM> are pulled tight, the peaks of the arcs of the proximal anchor <NUM> will be pulled proximally, thereby causing the proximal anchor <NUM> to fold or cinch up to form a funnel shape at the proximal end of the distal anchor <NUM> (crimps <NUM>, <NUM> of the proximal anchor <NUM> can be seen).

To expand the proximal anchor <NUM>, the wires <NUM> can either be withdrawn or loosened (such as with a lever <NUM> on the handle), thereby allowing the proximal anchor <NUM> to self-expand into place, as shown in <FIG>. Referring to <FIG>, in some embodiments, the wires 19a can be withdrawn completely, thereby allowing the proximal anchor <NUM> to expand. In another embodiment, shown in <FIG>, the retention wires <NUM> can be formed of loops that, when loosened, i.e. pushed distally, allow the distal anchor <NUM> to expand without releasing the anchor <NUM>. By using such a mechanism, the proximal anchor can be resheathed and moved (by retightening the retention members <NUM>) if necessary. A mechanism on the handle can then be used to release the retention members <NUM> entirely.

Referring to <FIG>, to deploy the valve prosthesis <NUM> in a valve (such as the mitral valve), the guidewire <NUM> and delivery device <NUM> can be inserted through the native valve. Referring to <FIG>, as the outer sheath <NUM> of the device <NUM> is retracted relative to the central longitudinal structure <NUM>, the distal anchor <NUM> of the valve prosthesis is exposed and self-expands (such as into the left ventricle). Once expanded, the distal anchor <NUM> may be retracted proximally against the distal-facing tissue of the cardiac chamber around the orifice, providing positive tactile feedback that the distal anchor <NUM> is oriented and positioned properly against the distal wall of the cardiac orifice. Further retraction of the sheath <NUM> exposes the central portion <NUM> of the valve prosthesis, allowing the central portion <NUM> to radially expand against the inner wall of the cardiac orifice.

Referring to <FIG>, to expand the prosthesis <NUM> on the other side of the cardiac orifice (i.e., in the left atrium), the central retention members <NUM> of the delivery device can be withdrawn or loosened as described above, thereby expanding the proximal anchor <NUM>. The expanded proximal anchor <NUM> provides a second backstop to the valve prosthesis <NUM>, allowing the prosthesis <NUM> to sandwich the valve orifice, such as the mitral valve orifice between the proximal and distal anchors <NUM>, <NUM>. As the device <NUM> expands, it foreshortens, moving the proximal anchor <NUM> and distal anchor <NUM> toward each other to provide a compressive force on tissue surrounding the cardiac orifice, such as the valve annulus.

Thus, in one example, as shown in <FIG>, the prosthesis can be delivered into the mitral valve orifice such that the distal anchor <NUM> sits within the left ventricle while the proximal anchor <NUM> sits within the left atrium. The struts <NUM> and leaflets <NUM> can extend distally into the left ventricle. Tissue of the mitral valve annulus can be captured between the anchors <NUM>, <NUM>. Further, the size of the prosthesis <NUM> can be such that the anchors <NUM>, <NUM> extend within the chambers of the heart and much wider than the diameter of the orifice itself, thereby allowing for strong tissue capture and anchoring. In some embodiments, placement of the prosthesis can move the existing leaflets valves out of the way.

In some embodiments, as described above, the valve prosthesis <NUM> can be repositioned using the delivery device <NUM>. That is, by pulling on the retention wires <NUM>, the proximal anchor <NUM> can be cinched back down with the proximal arcs extending proximally. The distal anchor <NUM> can be collapsed into the sheath (with the arcs extending distally) either by pulling proximally on the prosthesis <NUM> or pushing the sheath <NUM> distally.

Use of an alternative delivery device is shown in <FIG>. As shown in <FIG>, rather than including multiple retention wires, the delivery device can include a single elongate member <NUM> over which all of the arcs <NUM>, <NUM> of the proximal anchor <NUM> are placed.

<FIG> shows an embodiment of the valve prosthesis <NUM> where retention hooks <NUM> are built into the device. The hooks <NUM> extend toward the center of the device from the joints (e.g., crimps) of the distal anchor <NUM>. The hooks may be made of nitinol and are curved so that as the distal anchor <NUM> is drawn toward the center longitudinal member <NUM> of the delivery device <NUM>, the hooks flatten and collapse, allowing the outer sheath <NUM> of the delivery device <NUM> to slide smoothly over the hooks <NUM>. As the outer sheath <NUM> is removed from the valve prosthesis <NUM> during delivery and the distal anchor <NUM> of the valve prosthesis opens, the hooks <NUM> expand into the tissue of the cardiac orifice. In embodiment, the hooks <NUM> are only located on the distal anchor <NUM>, as the distal anchor <NUM>, when located on the ventricular side of the aorta, undergoes the highest pressure. In other embodiments, the hooks <NUM> are located on the proximal anchor <NUM> and/or the central portion <NUM>.

In one embodiment, small hooks in the distal anchor <NUM> may be used to grip the valve leaflets. As the distal anchor <NUM> is retracted from the ventricle toward the mitral valve annulus, the hooks can pull the leaflets into a folded position just under the ventricular side of the mitral annulus.

Claim 1:
A prosthetic mitral valve (<NUM>) comprising:
a valve frame configured to expand from a collapsed configuration to an expanded configuration and having a proximal anchor (<NUM>), a distal anchor (<NUM>), and a central portion (<NUM>) therebetween; and
the proximal anchor (<NUM>), distal anchor (<NUM>) and central portion (<NUM>) being formed of wire, the wire being joined at joints;
a plurality of leaflets (<NUM>) secured to the valve frame;
characterized in that the valve frame further has a plurality of curved retention hooks (<NUM>) located on the distal anchor to extend toward the center of the frame from joints of the distal anchor when the valve frame is in the expanded configuration, the plurality of retention hooks being configured to flatten and collapse when the valve frame is in the collapsed configuration.