Patent Description:
Conditions affecting the proper functioning of the mitral valve include, for example, mitral valve regurgitation, mitral valve prolapse and mitral valve stenosis. Mitral valve regurgitation is a disorder of the heart in which the leaflets of the mitral valve fail to coapt into apposition at peak contraction pressures, resulting in abnormal leaking of blood from the left ventricle into the left atrium. There are several structural factors that may affect the proper closure of the mitral valve leaflets. For example, many patients suffering from heart disease have an enlarged mitral annulus caused by dilation of heart muscle. Enlargement of the mitral annulus makes it difficult for the leaflets to coapt during systole. A stretch or tear in the chordae tendineae, the tendons connecting the papillary muscles to the inferior side of the mitral valve leaflets, may also affect proper closure of the mitral annulus. A ruptured chordae tendineae, for example, may cause a valve leaflet to prolapse into the left atrium due to inadequate tension on the leaflet. Abnormal backflow can also occur when the functioning of the papillary muscles is compromised, for example, due to ischemia. As the left ventricle contracts during systole, the affected papillary muscles do not contract sufficiently to effect proper closure.

Mitral valve prolapse, or when the mitral leaflets bulge abnormally up in to the left atrium, causes irregular behavior of the mitral valve and may also lead to mitral valve regurgitation. Normal functioning of the mitral valve may also be affected by mitral valve stenosis, or a narrowing of the mitral valve orifice, which causes impedance of filling of the left ventricle in diastole.

Mitral valve regurgitation is often treated using diuretics and/or vasodilators to reduce the amount of blood flowing back into the left atrium. Other treatment methods, such as surgical approaches (open and intravascular), have also been used for either the repair or replacement of the valve. For example, typical repair approaches have involved cinching or resecting portions of the dilated annulus.

Cinching of the annulus has been accomplished by the implantation of annular or peri-annular rings which are generally secured to the annulus or surrounding tissue. Other repair procedures have also involved suturing or clipping of the valve leaflets into partial apposition with one another.

Alternatively, more invasive procedures have involved the replacement of the entire valve itself where mechanical valves or biological tissue are implanted into the heart in place of the mitral valve. These invasive procedures are conventionally done through large open thoracotomies and are thus very painful, have significant morbidity, and require long recovery periods.

However, with many repair and replacement procedures, the durability of the devices or improper sizing of annuloplasty rings or replacement valves may result in additional problems for the patient. Moreover, many of the repair procedures are highly dependent upon the skill of the cardiac surgeon where poorly or inaccurately placed sutures may affect the success of procedures.

Compared to other cardiac valves, portions of the mitral valve annulus have limited radial support from surrounding tissue and the mitral valve has an irregular, unpredictable shape. For example, the inner wall of the mitral valve is bound by only a thin vessel wall separating the mitral valve annulus from the inferior portion of the aortic outflow tract. As a result, significant radial forces on the mitral annulus could lead to collapse of the inferior portion of the aortic tract with potentially fatal consequences.

The chordae tendineae of the left ventricle are often an obstacle in deploying a mitral valve repair device. The maze of chordae in the left ventricle makes navigating and positioning a deployment catheter that much more difficult in mitral valve repair. <CIT> discloses an implantable prosthetic heart valve device.

Given the difficulties associated with current procedures, there remains the need for simple, effective, and less invasive devices and methods for treating dysfunctional heart valves. In a first aspect of the present invention there is provided a device for resolving regurgitation in a cardiac valve as set forth in the claims.

The present technology is directed to cardiac valve devices, and in particular devices for treating regurgitant or incompetent cardiac valves. Although many of the applications are described with respect to the mitral valve, the present technology is not limited to mitral valve applications. The devices of the present technology are intended to repair but not replace the entire native valve.

Several embodiments of the present technology functionally extend one or more native leaflets to facilitate coaptation with other leaflets and thereby reduce regurgitation without piercing through the native leaflet. Some embodiments of the present technology are described with respect to the posterior leaflet of the mitral valve and providing an atraumatic coaptation surface for the anterior leaflet. However, the present technology may be also used to functionally extend the anterior leaflet while providing an atraumatic coaptation surface for the posterior leaflet.

<FIG> shows an example of a mitral valve having an anterior leaflet and a posterior leaflet. The anterior leaflet has a semi-circular shape and attaches to two-fifths of the annular circumference. The motion of the anterior leaflet defines an important boundary between the inflow (diastole) and outflow (systole) tracts of the left ventricle. The posterior leaflet of the mitral valve has a crescent shape and is attached to approximately three-fifths of the annular circumference. The posterior leaflet typically has two well-defined indentations which divide the leaflet into three individual scallops identified as P1 (lateral scallop), P2 (middle scallop), and P3 (medial scallop). The three corresponding segments of the anterior leaflet are identified as A1 (anterior segment), A2 (middle segment), and A3 (posterior segment). The leaflet indentations aid in posterior leaflet opening during diastole.

As shown in <FIG>, the mitral valve has anterolateral and posteromedial commissures which define a distinct area where the anterior and posterior leaflets come together at their insertion into the annulus. Sometimes the commissures exist as well-defined leaflet segments, but more often this area is a subtle structure, and can be identified using the following two anatomic landmarks: (a) the axis of corresponding papillary muscles, and (b) the commissural chordae, which have a specific fan-like configuration. Several millimeters of valvular tissue separate the free edge of the commissures from the annulus.

The mitral valve is an atrio-ventricular valve, separating the left atrium from the left ventricle. The mitral annulus constitutes the anatomical junction between the left ventricle and the left atrium. The fixed end of the leaflets is attached to the annulus. The anterior portion of the mitral annulus is attached to the fibrous trigones and is generally more developed than the posterior annulus. The right fibrous trigone is a dense junctional area between the mitral valve, tricuspid valve, non-coronary cusp of the aortic annuli, and the membranous septum. The left fibrous trigone is situated at the junction of both left fibrous borders of the aortic and the mitral valve.

The mitral annulus is less well developed at the insertion site of the posterior leaflet. This segment is not attached to any fibrous structures, and the fibrous skeleton in this region is discontinuous. This posterior portion of the annulus is prone to increase its circumference when mitral regurgitation occurs in association with left atrial or left ventricle dilation. The mitral annulus is saddle-shaped, and during systole the commissural areas move proximally, i.e. towards the roof of the atrium, while annular contraction also narrows the circumference. Both processes aid in achieving leaflet coaptation, which may be adversely affected by annular dilatation and calcification. The mitral annulus is surrounded by several important anatomic structures, including the aortic valve, the coronary sinus, and the circumflex artery.

Conventional approaches to addressing annular dilation of the mitral valve have primarily focused on reshaping the annulus using annuloplasty rings or joining the anterior and posterior leaflets to facilitate coaptation. These approaches may not be suitable in situations in which the gap or spacing between the opposing leaflets is too great. Several embodiments of the present technology are leaflet extension devices that functionally extend the native leaflet and attach to the native leaflet, such as without irreversibly disrupting the leaflet (e.g., without piercing into and/or completely through the leaflet), so that the leaflet extension devices can be repositioned and/or removed as needed.

There have also been prior attempts to extend a leaflet. Some conventional approaches utilize an anchoring mechanism which pierces through the leaflet. However, such approaches may be disfavored because they do not allow for repositioning and/or retrieval of the device. Other approaches use a device that extends a leaflet, but existing leaflet extensions are invasively affixed to leaflet by an anchor which pierces through the leaflet.

In contrast, the leaflet extension devices of the present technology non-invasively attach to the leaflet, such as without piercing through the leaflet, to enable repositioning and/or removal of the leaflet extension devices as needed.

<FIG> depict a leaflet extension device <NUM> configured for attachment to a native cardiac valve leaflet. In some embodiments, the leaflet extension devices <NUM> are configured to fill a gap of <NUM>-<NUM> between the anterior and posterior leaflets. Additionally, the leaflet extension devices are configured to be attached to the leaflet without irreversibly disrupting (e.g., permanently damaging) the leaflet. This is expected to enable the leaflet extension devices to be removed and repositioned as needed.

The leaflet extension device <NUM> is configured to provide a prosthetic coaptation surface in place of one of the valve leaflets (anterior or posterior). For the sake of simplicity, the device <NUM> will be explained with reference to the posterior leaflet of a mitral valve; however, the device <NUM> is similarly applicable to the anterior leaflet of the mitral valve and to leaflets other cardiac valves, such as the aortic or tricuspid valves.

The leaflet extension device <NUM> can comprise an expandable member <NUM> (shown in phantom in <FIG>) and a cover <NUM>. The device <NUM> has a coaptation portion <NUM>, a stabilizing portion <NUM>, and a fixation member <NUM>. The expandable member <NUM> has a delivery configuration suitable for being delivered through the vasculature in a catheter and a deployed configuration. In the deployed configuration, the coaptation portion <NUM> is positioned to provide a prosthetic coaptation surface for one or more native valve leaflets, and the stabilizing portion <NUM> and the fixation member <NUM> in combination are configured to secure the device <NUM> with respect to the valve anatomy. The cover <NUM> can be attached to or integral with the expandable member <NUM>.

The expandable member <NUM> may be a frame having a mesh material, a lattice-work frame, and/or one or more struts, or the expandable member may include an inflatable component (e.g., a bladder/balloon) in addition to or in lieu of the frame. In the illustrated example the expandable member <NUM> comprises a frame having primary struts <NUM> (shown in phantom) and cross-struts <NUM> (shown in phantom). The primary struts <NUM> can be joined at a first end <NUM> and extend to a second end <NUM> at the terminus of the fixation member <NUM>. The primary struts <NUM> can be configured to fan out from the first end <NUM> and bend in a region that defines the coaptation portion <NUM> in the deployed configuration.

<FIG> is a side view of a frame-type expandable member <NUM> without the cover <NUM>. The primary struts <NUM> can extend and fan out from a hub at the first end <NUM> to form an interior volume <NUM> within the coaptation portion <NUM> and the stabilizing portion <NUM>. The primary struts <NUM>, for example, can bend along the transition from the stabilizing portion <NUM> and through the coaptation portion <NUM>, and then all or a subset of the primary struts <NUM> can bend further from the coaptation portion <NUM> to define at least a portion of the fixation member <NUM>. The fixation member <NUM> can be a clip that, in the expanded configuration, contacts the stabilizing portion <NUM> to exert a tight clipping force on the native leaflet. The fixation member <NUM> can alternatively be separated from the stabilizing portion <NUM> by a gap <NUM> as shown in <FIG>. The cross-struts <NUM> can be configured to position the primary struts <NUM> so that the primary struts <NUM> retain the desired configuration after deployment.

In some of the examples depicted in <FIG>, the coaptation portion <NUM>, stabilizing portion <NUM> and fixation member <NUM> are integrally formed together. For example, the coaptation portion <NUM>, stabilizing portion <NUM> and fixation member <NUM> can be integrally formed by continuous primary struts <NUM> or cross-struts <NUM> of the expandable member <NUM>. In other examples, at least one of the coaptation portion <NUM>, the stabilizing portion <NUM> and/or the fixation member <NUM> can be a separate component from the others, or each of the coaptation portion <NUM>, stabilizing portion <NUM> and fixation member <NUM> can be separate from each other.

Referring to <FIG>, the coaptation portion <NUM> is intended to extend beyond the free end of the leaflet thereby providing a prosthetic coaptation surface that functionally extends the native cardiac valve leaflet. The coaptation portion <NUM> may have any smooth shape that mates with the opposing leaflet. The illustrated coaptation portion <NUM> in <FIG> is a closed loop or ring, but the technology is not limited to the illustrated examples as smooth shapes in general may be used. The coaptation portion <NUM> and the stabilizing portion <NUM> enclose the hollow interior volume <NUM> (<FIG> and <FIG>), which is sealed by the cover <NUM>. After implantation, the hollow volume <NUM> of the device <NUM> at least partially fills with blood, which will clot and be replaced by tissue over time. This may contribute to long-term fixation of the leaflet extension device <NUM>. The coaptation portion <NUM> in combination with the cover <NUM> provides an atraumatic coaptation surface for the opposing (anterior) native leaflet.

When the expandable member <NUM> is a frame, it can include struts and/or a mesh formed of any biocompatible material, such as plastic, stainless steel or a super-elastic self-expanding material such a nickel-titanium alloy, e.g., Nitinol®. The cover <NUM> may be a biocompatible fabric formed of a polymer or biomaterial (Polyethylene terephthalate (PET), expanded polytetrafluoroethylene (ePTFE), silicone, urethane, pericardium, etc.). The cover <NUM> may be attached to the struts <NUM>, <NUM> by sutures, adhesives, sintering, and/or other suitable attachment techniques.

In operation, the fixation member <NUM> is biased toward the stabilizing portion <NUM> such that the native leaflet is clamped in the gap <NUM> between the fixation member <NUM> and the stabilization portion <NUM> upon deployment. One aspect of several embodiments of the present technology is that the stabilizing portion <NUM> and the fixation member (ventricular) <NUM> clamp onto the native leaflet without piercing the native leaflet. The fixation member <NUM> may include one or more clips configured to clamp to the atrial and ventricular sides of the leaflet, or the like. In the non-limiting example depicted in <FIG>, the fixation member <NUM> may be a clip which abuts the ventricular side of the native leaflet while the stabilizing portion <NUM> abuts the atrial side of the native leaflet, but this arrangement may be reversed if desired. In either case the native leaflet is clamped (e.g., sandwiched) between the stabilizing portion <NUM> and the fixation member <NUM>. In some examples, the leaflet extension device <NUM> is affixed to the native leaflet solely by the compressive force of the stabilizing portion <NUM> and the fixation member <NUM> without piercing through the native leaflet.

Referring to <FIG>, the device <NUM> may further include frictional elements <NUM> such as cleats which engage or tent into the leaflet. The frictional elements <NUM> may extend from the stabilizing portion <NUM> and/or fixation member <NUM>. For example, or the frictional elements <NUM> may be attached to or integrally formed with the stabilizing portion <NUM> and/or the fixation member <NUM>. The frictional elements <NUM> may be sharpened to facilitate engagement with the leaflet. In some cases, the frictional elements <NUM> may penetrate into the native cardiac valve leaflet without piercing completely through the native leaflet. In other cases, the frictional elements <NUM> pierce completely through the full thickness of the native valve leaflet.

The leaflet extension device <NUM> is intended to be delivered and implanted in a beating heart using a minimally invasive technique. For example, the leaflet extension may be delivered via a catheter using a transfemoral approach. The leaflet extension device <NUM> is attached to the desired leaflet using the fixation member <NUM>.

The stabilizing portion <NUM> and/or the fixation member <NUM> may be sized to engage with all or a portion of the native leaflet. When they engage the entire leaflet they may support a torn leaflet. Alternatively, the stabilizing portion <NUM> and/or the fixation member <NUM> may be sized to engage with only a portion of the native leaflet, e.g., central scallop P2 of the posterior leaflet, leaving scallops P1 and P3 mobile. In this example, P1 and P3 are free to coapt with the anterior leaflet (opposing leaflet).

<FIG> is an isometric view of the device implanted in a native mitral valve as viewed from the left atrium, and <FIG> illustrate an example of implanting the leaflet extension device <NUM> at a native mitral valve. The leaflet extension device <NUM> can be compressed into a tubular sheath for delivery via a trans-septal or trans-atrial access. It could also be delivered via trans-apical access or trans-aortic access. Referring to <FIG>, a delivery catheter <NUM> or sheath can be positioned in the left atrium LA above the P2 portion of the posterior leaflet PL of the mitral valve. A device catheter <NUM> can then be advanced through the delivery catheter <NUM> and positioned at the native valve near the middle of the P2 leaflet edge of the posterior leaflet PL while the leaflet extension device <NUM> (<FIG>) is still contained within the device catheter <NUM>, as shown in <FIG>. Referring to <FIG>, as the fixation member <NUM> is then partially released from the device catheter <NUM>, the fixation member <NUM> folds against the ventricular surface of the leaflet. During this process, the physician can confirm that the leaflet extension device <NUM> is at the appropriate height and that the fixation member <NUM> passes between the chordae. <FIG> shows the process after the fixation member <NUM> has been fully deployed and stabilizing portion <NUM> is partially deployed such that the stabilizing member splays medially and laterally. <FIG> illustrates the process after the leaflet extension device <NUM> has been deployed such that the expansion member <NUM> (<FIG>) has expanded to the deployed configuration. At this stage of the process, the posterior leaflet PL is clamped between the stabilizing portion <NUM> and the fixation member <NUM>, while the anterior leaflet Al coapts against the atraumatic surface of the coaptation portion <NUM>. Once the sheath is retracted to the atrial end of the device <NUM>, the effectiveness of the device in reducing or eliminating mitral regurgitation can be assessed. At this stage the leaflet extension device <NUM> is functionally deployed but still connected to the delivery catheter. If the device <NUM> is performing appropriately, it may be detached/disengaged from the delivery catheter. If not, the device catheter <NUM> and/or the delivery catheter <NUM> can be re-advanced to linearize and compress the device <NUM> for removal or repositioning.

The shape of the leaflet extension device <NUM> can be configured to enhance its effectiveness in engaging the native posterior leaflet and/or coapting with the native anterior leaflet. <FIG> shows the leaflet extension device <NUM> with the stabilizing portion <NUM> and/or the fixation member <NUM> configured such that they hold the posterior leaflet PL in approximately the natural curved shape of the native leaflet. <FIG> shows the leaflet extension device <NUM> with the stabilizing portion <NUM> and/or the fixation member <NUM> configured such that they hold the native posterior leaflet PL in a relatively flattened shape. The flattened shape shown in <FIG> may position the leading edge of the native leaflet and the chordae tendineae slightly closer to the anterior leaflet (not shown). The coaptation portion <NUM> may have a somewhat concave shape on the atrial side of the posterior leaflet PL, as seen in <FIG>, to position the coaptation surface of the coaptation portion <NUM> to coapt with the native anterior leaflet. The coaptation portion <NUM> may have a curved or even round shape as seen in cross-section in <FIG>, or a somewhat more linear vertical shape as seen in <FIG>, so that the anterior leaflet has a consistent coaptation surface over a range of leaflet heights. The specific shape of the device <NUM> could be varied to address different anatomical variations between patients, such as partial flail leaflets in patients with degenerative disease, or tethered leaflets in patients with functional mitral disease. The shape could also be varied to accomplish various types of coaptation geometries. The coaptation portion <NUM> could be relatively vertical. Other options include configurations in which the anterior leaflet can close against the ventricular aspect of the implant in a "trapdoor" geometry.

<FIG> illustrate the leaflet extension device <NUM> from the left atrium after implantation. The device <NUM> may extend along approximately <NUM>-<NUM> of the posterior leaflet PL edge and follow the curved edge of the posterior leaflet PL. The coaptation portion <NUM> may curve slightly in the opposite direction as shown in <FIG>, or it may be relatively more straight as shown in <FIG>.

The length of the native leaflet measured from the annulus to the leaflet edge is in the range of approximately <NUM>-<NUM>. The stabilizing portion <NUM> of the device <NUM> abuts the atrial surface of the posterior leaflet PL and may be relatively straight, as shown in <FIG>, or the stabilizing portion <NUM> may be bulbous (e.g., splayed) to engage/support as much surface area of the native leaflet as possible as shown in <FIG>.

The stabilizing portion <NUM> may extend beyond the fixed end of the leaflet and partially up the atrial wall above the mitral annulus, as shown in <FIG>. This configuration of the stabilizing portion <NUM> increases the longitudinal dimension of the device <NUM> so that it can readily expand laterally and cover more of the atrial surface to further enhance the stability of the device <NUM>. For example, such a long stabilizing portion <NUM> may brace the device <NUM> against the atrial wall to inhibit the device <NUM> from flipping into the left atrium under systolic blood pressure and can thus facilitate treatment of mitral regurgitation due to posterior leaflet flail or prolapse.

The cover <NUM> of the device <NUM> shown in <FIG> may promote ingrowth into the atrial wall. This ingrowth may result in the middle scallop P2 of the posterior leaflet assuming the closed position permanently such that the middle scallop P2 would effectively act as a stop. The device <NUM> may include an anchoring mechanism (not illustrated) such as a screw, tack, an eyelet for a screw or tack, or the like useful for fixing the end of the stabilizing portion <NUM> to the atrial wall or the mitral annulus.

The posterior leaflet of the human mitral valve typically has a gap between the posteromedial and anterolateral groups of chordae, which may be approximately <NUM>-<NUM> wide, and the fixation member <NUM> can be configured to be consistently positioned between the chordae tendineae (CT). <FIG>, for example, shows a fixation member <NUM> of the device <NUM> configured to lay against the ventricular surface of the native posterior leaflet. The fixation member <NUM> shown in <FIG> has a relatively narrow width and pointed/rounded tip that can be predictably positioned in the gap between the chordae tendineae CT.

<FIG> show various examples of the fixation member <NUM> that are linear (<FIG>), spade-shaped (<FIG>) or splayed-shape (<FIG>). The wider fixation members <NUM> shown in <FIG> may help stabilize the device <NUM>, such as when a portion of the posterior leaflet may be flailing or prolapsing.

Referring to <FIG>, the fixation members <NUM> may extend into the naturally occurring alcove AA located between the ventricular wall muscle and the posterior leaflet. This extension of the fixation member <NUM> may enhance the stabilization of the device <NUM>, which is expected to make it easier to form a more secure contact with the native leaflet and to inhibit it from flipping upward under systolic blood pressure.

In some of the previously described embodiments, one or more of the fixation members <NUM> extend through the gap between the posteromedial and anterolateral groups of chordae and press against the ventricular surface of the posterior leaflet to hold the implant in place. One or more fixation members <NUM> may also extend under the posterior leaflet more medially and laterally, passing between chordae wherever they conveniently pass. Such embodiments may require that the device <NUM> be expanded laterally and medially before such fixation members are extended between the chordae to avoid being bunched in the central gap between the chordae. In several applications it is desirable to have the fixation members <NUM> fold into only the central gap between the medial and lateral groups of chordae to mitigate entangling the fixation member <NUM> with the chordae.

<FIG> shows a leaflet extension device <NUM> having a first fixation member 116a and second fixation members 116b. The first fixation member 116a can be similar to the fixation members <NUM> described above with respect to <FIG>. The second fixation members 116b are nearer the lateral and medial margins of the device, and in such cases it may be advantageous to deploy the second fixation members 116b or other ventricular elements after initially deploying the device <NUM>. For example, after the device <NUM> has expanded medially and laterally, the second fixation members 116b can be advanced into gaps between the chordae. In some embodiments, the second fixation members 116b can be advanced through tubes <NUM> attached to the lateral and medial portions of the device <NUM>. The tubes <NUM> may be formed of polyimide or the like, and they may be attached to the expandable member <NUM> or the cover <NUM> of the device <NUM>. For example, the tubes <NUM> can be attached to the expandable member <NUM> at the same time as the cover <NUM> is attached, such as by sewing all of these elements to each other. It may be desirable to have one or more of the struts of the stabilizing portion <NUM> (<FIG>) include a lumen sized to accommodate the second fixation members 116b thereby eliminating the need for the tubes <NUM>.

The second fixation members 116b may be formed of a resilient material such as a super-elastic nickel-titanium alloy, e.g., Nitinol®, pre-formed to follow the shape of the deployed implant so that they are biased to apply pressure to the ventricular surface of the native leaflet. The second fixation members 116b can also include an atraumatic end, such as paddles or loops, that have an increased surface area to maximize their grip strength and mitigate trauma to the native leaflet.

The device <NUM> may be easier to position in the native valve with fixation members <NUM> that are not integral continuations of the struts that form the coaptation portion <NUM>. The fixation members <NUM> can accordingly be separate struts that are advanced individually or together against the ventricular surface of the posterior leaflet. <FIG>, for example, shows such a device <NUM> with fixation members <NUM> similar to the second fixation members 116b that are advanced through tubes <NUM> to be positioned against the ventricular surface of the native leaflet.

<FIG> show variations of expandable members <NUM> suitable for use in the device <NUM>. The expandable member <NUM> can be cut from a flat sheet of nickel-titanium alloy with numerous primary struts <NUM> and cross-struts <NUM>. As best shown in <FIG>, a number of the central primary struts <NUM> can extend continuously through the stabilizing portion <NUM>, the coaptation portion <NUM>, and the fixation member <NUM>. The stabilizing portion <NUM> of the struts <NUM> can be biased to lay against the atrial surface of the posterior leaflet, and the coaptation portion <NUM> can be configured to define the support for the prosthetic coaptation surface. The coaptation portion of the primary struts <NUM> can be supported by the cross-struts <NUM> to enhance the stability of the device <NUM>. In the example shown in <FIG>, there are four primary struts configured to lay against the atrial surface and five primary struts <NUM> are configured that define the structure of the coaptation surface <NUM>. The fixation structure <NUM> is supported by the three central primary struts <NUM> so that the fixation structure <NUM> extends under the ventricular surface of the posterior leaflet.

To deliver the device <NUM> from a femoral venous access site via a trans-septal puncture, the outer diameter of the entire device <NUM> and delivery system should generally not exceed <NUM> French (<NUM> diameter), although larger diameters may be suitable for some applications. As a result, if the device <NUM> has nine primary support struts <NUM> arrayed linearly, each primary support <NUM> can have a maximum width of <NUM> (<NUM> inch) as a non-limiting example.

To achieve smaller diameters, the device <NUM> can be constructed by cutting a cylindrical nickel-titanium alloy tube with a number (perhaps <NUM>-<NUM>) of linear elements (e.g., primary struts <NUM>). These linear elements could be connected by cross-struts (e.g., chevrons) or other flexible elements for strength, stability, and enhanced friction against the leaflet surface. Approximately half of the linear elements can define the stabilizing portion <NUM>, which can be configured to follow the atrial surface of the posterior leaflets, and half of the linear elements can define the coaptation portion <NUM>, which can be curved to create the leaflet extension shape.

<FIG> shows an embodiment of the device <NUM> having a somewhat flattened shape and cross-struts <NUM> that project outwardly for enhanced fixation. In such embodiments, the cross-struts <NUM> at the edges of the device <NUM> might extend further laterally and medially to further stabilize the device <NUM>. If a portion of the posterior leaflet was flailing or there was a misalignment between the P1-P2 or P2-P3 segments of the native leaflet, such expanded cross-struts <NUM> may further stabilize and align the leaflet segments.

<FIG> and <FIG> show aspects of the expandable member <NUM> of the device <NUM> having individual fixation members <NUM>. The primary struts <NUM> can extend from the first end <NUM> and through the stabilizing portion <NUM> and the coaptation portion <NUM> such that the primary struts <NUM> extend to a point underneath the posterior leaflet. The device <NUM> can have primary struts <NUM> with lumens though which individual fixation members <NUM> can be moved from a retracted position to an extended position. As a result, individual fixation members <NUM> can be extended from the primary struts <NUM> to engage the ventricular surface of the native leaflet and hold the implant <NUM> in place. The device <NUM> in <FIG> has independently advanceable fixation members <NUM> at the lateral and medial edges of the implant <NUM>. Alternatively, all of the fixation members <NUM> of the device <NUM> shown in <FIG> are independently advanceable. The primary struts <NUM> may be hollow metal or polymeric tubes. In other embodiments, the devices <NUM> shown in <FIG> and <FIG> have solid primary struts <NUM> and separate tubes, such polyimide tubes, are affixed to the primary struts <NUM>. If such separate tubes are attached to the sides of the primary struts <NUM> corresponding with the inside diameter of the tubes, then when the implant <NUM> is compressed for delivery the overall device diameter would be minimized. The coaptation portion <NUM> can be covered by a fabric covering as described above.

<FIG> further illustrates an extension mechanism <NUM> for extending/retracting the fixation members <NUM>. The extension mechanism <NUM> can include individual wires having a proximal portion <NUM>, a distal portion <NUM>, and an atraumatic tip <NUM>. The distal portions <NUM> and the tips <NUM> of the wires define the fixation members <NUM>. The proximal portion <NUM> of each movable wire may extend proximally to a handle or be releasably attached to a separate push-wire in the delivery system. This would enable the independent movement of each wire into the appropriate position. Alternatively, the extension mechanism <NUM> could have a plunger <NUM> and one or more of the wires can be attached to the plunger <NUM> so that the wires attached to the plunger could all be advanced/retracted simultaneously (as shown in FIG. This would simplify the structure of the delivery catheter, speed up the implantation process, and simplify the release of the implant from the delivery catheter.

<FIG> show the device <NUM> having a coaptation portion <NUM> that is deployed independently with respect to the stabilizing portion <NUM>. For example, the coaptation portion <NUM> can have separate elements that are deployed by advancing them relative to the elements of the stabilizing portion <NUM>. The coaptation portion <NUM> could be adjustable so that by further advancing the coaptation portion relative to the stabilizing portion <NUM>, the implant <NUM> could be expanded to further improve coaptation.

<FIG> show some embodiments of the device <NUM> in which the stabilizing portion <NUM> and coaptation portion <NUM> are linked at the distal region of the stabilizing portion <NUM>. More specifically, the stabilizing portion <NUM> has first primary struts 120a and eyelets <NUM> at the ends of the first primary struts 120a, and the coaptation portion <NUM> has second primary struts 120b configured to extend through the eyelets <NUM>. The devices <NUM> can further include cross-struts <NUM> between the first primary struts 120a of the stabilizing portion <NUM>. The first primary struts 120a of the stabilizing portion <NUM> can be cut from one flat metal sheet (e.g., a shape memory material such as Nitinol), and the second primary struts 120b of the coaptation portion <NUM> can be cut from a second metal sheet (e.g., a shape memory material such as Nitinol; see, e.g., <FIG> and <FIG>).

<FIG> and <FIG> show how the first and second primary struts 120a-b are configured to have curves approximating the desired final shape in the expanded state. The device <NUM> shown in <FIG> has central second primary struts 120b that are connected at their distal ends to define a fixation portion <NUM>. The device <NUM> shown in <FIG> has separate second primary struts 120b that curve separately from each other to define a plurality of fixation members <NUM>. The second primary struts 120b of the coaptation portion <NUM> pass through the openings/eyelets <NUM> at the distal ends of the first primary struts 120a of the stabilizing portion <NUM>. The first and second primary struts 120a and 120b made may be held together at the proximal end of the device <NUM>.

Once the device <NUM> is deployed with the stabilizing portion <NUM> pressing against the surface of the posterior leaflet and splayed laterally and medially, the coaptation portion <NUM> can be further advanced so that the distal extensions of the of the second primary struts 120b, which define the fixation members <NUM>, fold under against the ventricular surface of the posterior leaflet. This motion clamps the device <NUM> in place while simultaneously raising the coaptation portion <NUM> and extending the posterior leaflet towards the anterior leaflet.

<FIG> show the deployment sequence of the device <NUM> shown in <FIG>. <FIG> shows the device <NUM> after it has been partially exposed from the distal portion of a delivery catheter <NUM>. At this point, the stabilizing portion <NUM>, the coaptation portion <NUM>, and the fixation members <NUM> can be at least substantially aligned with each other. <FIG> shows the device <NUM> after the coaptation portion <NUM> begins to bend, and <FIG> shows the device <NUM> after the stabilizing portion <NUM>, the coaptation portion <NUM> and the fixation members <NUM> have moved into their deployed shapes.

<FIG> show an embodiment of a leaflet extension device <NUM> that can be similar to any of the devices shown and described above with reference to <FIG>, but the device <NUM> in <FIG> has an atrial stabilizer <NUM>. The device <NUM> shown in <FIG> can have a stabilizing portion <NUM> with eyelets <NUM>, a coaptation portion <NUM>, and a fixation member <NUM>. In the illustrated embodiment, the stabilizing portion <NUM> has first primary struts 120a, the coaptation portion <NUM> has second primary struts 120b that may be extendable from the first primary struts 120a, and the fixation portion <NUM> can have third primary struts 120c. The stabilizing portion <NUM> and the fixation member <NUM> can further include cross-struts <NUM>. The coaptation portion <NUM> can slide through the eyelets <NUM> to extend the coaptation portion <NUM> and the fixation member <NUM> with respect to the stabilizing portion <NUM> as described above with respect to <FIG>.

The atrial stabilizer <NUM> is configured to engage the atrial wall of the heart. The atrial stabilizer <NUM> is depicted as a rectangular element surrounding opening <NUM>, but the atrial stabilizer <NUM> can be a strut or series of struts or any polygonal, circular, elliptical, oval or other shape suitable for engaging the atrial wall. In use, the atrial stabilizer <NUM> is configured to contact or otherwise engage the atrial wall, and the atrial stabilizer <NUM> may include frictional elements such as cleats and/or a fabric covering. The atrial stabilizer <NUM> may also include a fabric covering to promote tissue ingrowth and/or encapsulation which may provide additional long-term fixation for the leaflet extension device <NUM>.

The leaflet extension device <NUM> of <FIG> is configured to be deployed with the stabilizing portion <NUM> pressing against the atrial surface of the posterior leaflet and splayed laterally and medially. Advancement of the coaptation portion <NUM> causes the fixation member <NUM> to fold against the ventricular surface of the posterior leaflet thereby clamping the device in place while simultaneously raising the coaptation portion <NUM> and extending the posterior leaflet towards the anterior leaflet.

The devices <NUM> shown and described above with respect to <FIG> can include additional features directed to specific functions. For example, advancing the coaptation portion <NUM> with respect to the stabilizing portion <NUM> could simultaneously deploy frictional elements, barbs, chevrons, or anchors formed with and/or on the stabilization portion <NUM>. For example, advancing the coaptation portion <NUM> could drive such frictional elements down against, into, or through the atrial surface of the native leaflet. The devices <NUM> could also include locking elements (not illustrated) which lock the coaptation portion <NUM> in a specific position relative to the stabilizing portion <NUM>. For example, the devices could have locking tabs or elements that are selectively deployed with more or less of an extension to the native leaflet. Also, the relative thickness of the stabilizing portion <NUM>, coaptation portion <NUM>, and fixation member <NUM> at each point along their length can be varied to achieve the desired range of shapes based upon the degree of deployment. In an alternative construction, the coaptation portion <NUM> could have separate second primary struts 120b that can be advanced individually to adjust the relative extension of the device <NUM> along the line of coaptation.

<FIG> shows a leaflet extension device <NUM> having an expandable member <NUM> including inflatable balloon or bladder <NUM>. The inflatable balloon or bladder <NUM> can be used in any of the leaflet extension devices <NUM> described and shown above with reference to <FIG> either in addition to or in lieu of the frame having one or more primary struts and/or cross-struts. The inflatable bladder <NUM> may be inflated once the device is in place at the native valve. The bladder <NUM> may have a coaptation portion <NUM> configured to face the opposing leaflet such that the bladder <NUM> coapts with the opposing leaflet. The bladder <NUM> can be inserted into the hollow internal volume <NUM> (<FIG>) enclosed by the stabilizing portion <NUM> and the coaptation portion <NUM> shown and described above with reference to <FIG>. Inflating the bladder <NUM> pushes the coaptation portion <NUM> toward the opposing cardiac valve leaflet (e.g., the anterior leaflet). The bladder <NUM> can be inflated as much as needed to provide coaptation with the native anterior leaflet and eliminate regurgitation.

<FIG> show an example leaflet extension device <NUM> which includes two members <NUM>, <NUM>. Member <NUM> has a first end 1702A and an opposed second end 1702B. Member <NUM> has a first end 1704A and an opposed end 1704B. The second end 1702B is attached to second end 1704B using conventional methods of attachment including screws, rivets or the like. The members <NUM>, <NUM> may be formed of any biocompatible material including plastic, metal or the like. For example, the members <NUM>, <NUM> may be formed of stainless steel, a nickel titanium alloy such as Nitinol®, or a Cobalt-Chromium-Nickel-Molybdenum alloy such as Elgiloy®. Members <NUM> and <NUM> may be formed of a solid sheet of material, a mesh, one or more struts, a lattice-work frame or the like.

Member <NUM> has a first face 1702F and an opposed second face <NUM>. Member <NUM> has a first face 1704F and an opposed second face <NUM>. The first face 1702F of the first member <NUM> abuts the first face 1704F of the second member <NUM>. The first end 1704A of the second member <NUM> is not attached to the first member <NUM> and is resiliently displaceable relative to the first member <NUM>.

The first and second members <NUM>, <NUM> cooperatively sandwich and grip the first native leaflet without piercing through the leaflet. The first and/or the second members may include frictional engagement members which may frictionally engage (tent into without piercing) with the native cardiac valve leaflet or the frictional engagement elements may pierce into but not through the native cardiac valve leaflet.

The leaflet extension device <NUM> includes a coaptation element <NUM> attached to the second face <NUM> of the first member <NUM>. The coaptation element <NUM> may have a teardrop shape and may include a convex portion 1703C extending beyond the second end 1702B, the coaptation element <NUM> preferably has a smooth outer surface for atraumatically coapting with a second native leaflet (not illustrated).

The coaptation element <NUM> may be formed of a biocompatible foam which may or may not include an internal framework. Alternatively, the coaptation element <NUM> may be formed of a framework <NUM> formed of one or more interconnected struts or a mesh. The framework <NUM> encloses a hollow interior volume which is sealed by a fabric covering <NUM>.

A tether <NUM> is operatively connected to the first and second members <NUM>, <NUM>. In some embodiments the tether <NUM> is used to actively displace the second member <NUM> relative to the first member <NUM>. The tether may be formed of a variety of biocompatible materials including a metallic wire such as stainless steel, a polymeric suture formed of expanded Polytetrafluoroethylene (ePTFE), ultra-high molecular weight polyethylene (UHMWPE), or polyester.

The first member <NUM> and/or the second member <NUM> may be formed of a super-elastic alloy which resiliently deforms from a native shape to a deformed shape in response to an external force but which resumes the native shape once the external force is removed, wherein pulling on the tether <NUM> resiliently displaces the second member <NUM> relative to the first member <NUM>.

An atrial stabilization member <NUM> may be provided on end 1702A-<NUM> of the first member <NUM> which can be attached to wire forms that help provide atrial stabilization.

In some cases, it may be desirable to increase the effective clamping force. Adding an expandable element between the native leaflet and either the fixation member <NUM> or the stabilizing portion <NUM> may increase the effective clamping force against the leaflet and improve the fixation of the leaflet extension device <NUM>. For example, <FIG> show devices that include expandable elements <NUM>. Although expandable elements <NUM> can be placed on the atrial side of the leaflet, the present disclosure focuses on adding the expandable element <NUM> between the fixation member <NUM> of the leaflet extension device and the ventricular surface of the native cardiac valve leaflet. Having the expandable element under the leaflet may limit motion of the device and provide a more stable structure for the opposing leaflet to close against.

For example, expandable element <NUM> may also restrict the motion of the leaflet by interfering with the leaflet's ability to open fully. The expandable element <NUM> may expand towards the ventricular wall, so that the expandable element touches the ventricular wall intermittently or continuously during the cardiac cycle. This may be advantageous for many reasons. It could stabilize the device <NUM> and/or the leaflet, reducing excessive motion and any wear, stress, or trauma on the implant, the clipped leaflet, the anterior leaflet, or adjacent leaflets.

Expandable element <NUM> could potentially reduce any regurgitation in the repaired valve in a variety of ways. It could improve the ability of the leaflet extension device <NUM> to coapt with the opposing leaflet by pushing the leaflet extension device <NUM> towards the opposing leaflet. It could also improve the ability of the prosthetic device <NUM> to coapt with adjacent leaflets, such as the P1 and P3 cusps of the posterior leaflet, either by holding the P2 leaflet in a more appropriate position or by creating a surface against which the P1 and P3 can coapt.

<FIG> show examples of the expandable element <NUM> in cross-section. <FIG> shows the device <NUM> when it is first placed, and <FIG> after expansion of the expandable element <NUM>. The cross-sectional shape of the expandable member <NUM> could have a variety of profiles, as shown in the differences between <FIG>. For example, the native leaflet can be held in a flattened or curved shape, the expandable element <NUM> can be generally round, triangular, or polygonal in cross-section, and the expandable element <NUM> can extend towards the ventricular wall or not.

In addition to the cross-sectional profile of the expandable element <NUM>, the profile of the expandable element <NUM> in other dimensions is equally important. For example, the fixation member <NUM> might be made with a relatively narrow distal profile, to make it easier to place into the chord-free area of the posterior leaflet. When the expandable element <NUM> is expanded between the fixation member <NUM> and the ventricular surface of the leaflet, the distal end of the expandable element <NUM> may be much wider where it contacts the ventricular surface of the leaflet, as shown in <FIG> and <FIG>. This may give the expandable element <NUM> a somewhat triangular profile facing the ventricular wall. Nearer the leaflet edge, the fixation member <NUM> may be approximately as wide as the chord-free zone of the leaflet edge, and the expandable element <NUM> may be as wide or somewhat wider.

As mentioned above, the expandable element <NUM> could extend posteriorly to touch or press against the ventricular wall at all times. Alternatively, it could be designed to minimize contact with the posterior wall, so that at least some range of motion remains possible for the posterior leaflet. This would allow the posterior leaflet to open somewhat in diastole, reducing any potential gradient through the mitral valve. Such a shape might also allow the leaflet and the implanted device to be pushed out of the way against the ventricular wall if it is necessary to implant a prosthetic replacement mitral valve at a later date.

The expandable element <NUM> could also be designed to expand laterally under the ventricular side of cusps P1 and P3 of the native leaflet. Lateral expansion of the expandable member <NUM> could bridge any gaps between P1 and P2 or P2 and P3. They could also hold P1 and P3 in a generally closed position in alignment with the P2 leaflet. However, there may be strut chordae, tertiary chordae, or even primary chordae which might tend to interfere with the expansion of these lateral extensions. Therefore, these lateral extensions might be designed to be very low-pressure, highly expandable balloon elements which can expand around and between chordae, or they could be multiple finger-like extensions to extend between chordae, as shown in <FIG>.

The expandable element <NUM> itself could comprise an inflatable balloon or bladder. The bladder could be constructed to expand to a specific size and shape, to achieve the specific design goals outlined above. Alternatively, it could be an expandable elastic balloon, which expands in a more spherical shape until it is constrained by the rest of the device, by the chordae or valve leaflets, or by the ventricular wall.

The expandable element <NUM> might also have rigid or semi-rigid elements attached to it. Referring to <FIG>, the device may include fictional elements <NUM>, such as bumps, spikes, or other features, which improve the frictional engagement with the valve leaflet. Alternatively, the frictional elements <NUM> might be rigid or semi-rigid linear elements to constrain the expandable element <NUM> into the potential shapes described above, such as a triangular, prismatic, or polyhedral shape. For example, the expandable element <NUM> may have rigid linear elements affixed to the surface which apposes the ventricular surface of the leaflet to help it engage firmly with an area of the leaflet. When the expandable element <NUM> is collapsed for delivery, these elements will align with the fixation member <NUM> to minimize the delivery profile. These rigid linear elements may also have ridges, grooves, bumps, spikes, or other features which further enhance the frictional engagement with the surface of the valve leaflet.

The expandable element <NUM> can be a balloon or bladder manufactured from any biocompatible material, such as urethane, expanded PTFE, polyester, polyolefin, or other materials, or a combination thereof. For example, the bladder might have an outer surface of expanded PTFE, to optimize tissue ingrowth and the tissue compatibility of the coaptation surfaces, and an inner layer of urethane to seal the bladder for leak-free inflation.

During delivery, the expandable element <NUM> might be delivered with an inflation tube inserted for inflation. This inflation tube would extend up through the delivery catheter of the device. Once the expandable element <NUM> is inflated to the desired shape or volume, the tube can be withdrawn to leave the expandable element <NUM> permanently inflated to that size.

The expandable element <NUM> could be inflated with a polymer or polymers which cross-link or cure over a period of time, so that the size and shape of the bladder is permanent. Examples of such polymers are polyethylene glycols, silicones, methacrylates, or others. The expandable element <NUM> may also be filled with coiled and/or braided structures formed of a biocompatible materials. These coils may be similar to the coils used for endovascular coiling. Alternatively, the expandable element <NUM> could be inflated with saline or other biocompatible solutions which remain liquid forever. In this way, if it were desirable to deflate the expandable element <NUM> in the future, for example to make room for implantation of a prosthetic mitral valve, this could be accomplished by piercing the bladder with a needle to pop it. This could be done using interventional catheter techniques.

The expandable element <NUM> could alternatively be made from an elastomeric member or an expandable mechanical structure. For example, the expandable element <NUM> could be an additional super-elastic frame, braid, coil, or mesh. This would allow it to be collapsed to a low profile for delivery, and then self-expand once it is in position. The braid or mesh structure can also be made out of Stainless Steel or Cobalt-Chromium-Nickel-Molybdenum alloy (e.g., Elgiloy®). Such an expandable element <NUM> could have an opening allowing the internal volume to fill with blood during or after expansion.

The previous embodiments have described an implantable leaflet extension device with fixation and stabilization elements formed from a super elastic Nickel-Titanium alloy (e.g. Nitinol®) frame which can be folded around the edge of the valve leaflet. As an alternative approach, this frame could be manufactured from stainless steel, cobalt-chromium steel, a "super-alloy" such as Elgiloy® which consists of <NUM>-<NUM>% Cobalt, <NUM>-<NUM>% Chromium, <NUM>-<NUM>% Nickel, <NUM>-<NUM>% Iron, <NUM>-<NUM>% Molybdenum, and <NUM>-<NUM>% Manganese, or other biocompatible metals or metal alloys which are stronger and stiffer than Nitinol® but do not exhibit similar super elasticity. If the leaflet extension device <NUM> was made of these metals, it would have enough elasticity to fan out laterally but not enough to fold around the edge of the leaflet. Therefore, such a device with a non-super-elastic frame might be pre-formed in a u-shape so that it could be hooked under the posterior leaflet, as shown in <FIG>. Such a device might also be formed in a "V"-shape, with a sharp edge rather than a curved edge along the edge of the extended leaflet. Such a design would not necessarily enclose a volume which would fill with blood.

Claim 1:
A device (<NUM>) for resolving regurgitation in a cardiac valve, comprising:
an expandable member (<NUM>) having a stabilizing portion (<NUM>), a fixation member (<NUM>)
in opposition to the stabilizing portion (<NUM>), and a coaptation portion (<NUM>) between the stabilizing portion (<NUM>) and the fixation member (<NUM>), wherein-the stabilizing portion and the coaptation portion comprise a plurality of interconnected struts,
the fixation member (<NUM>) comprises at least one primary strut (<NUM>) and the fixation member (<NUM>) is attached to the stabilizing portion (<NUM>),
the stabilizing portion (<NUM>) and the fixation member (<NUM>) are configured to clamp the first native leaflet between the stabilizing portion (<NUM>) and the fixation member (<NUM>), and
the coaptation portion (<NUM>) is configured to project from the stabilizing portion (<NUM>) and the fixation member (<NUM>) inwardly with respect to a first native leaflet of a cardiac valve such that the coaptation portion (<NUM>) functionally extends the first native leaflet; and
a cover (<NUM>) attached to at least the coaptation portion (<NUM>) of the expandable member (<NUM>).