FIELD

This disclosure relates generally to prosthetic devices and related methods for helping to seal native heart valves to prevent or reduce regurgitation therethrough, as well as devices and related methods for implanting such prosthetic devices.

BACKGROUND

The native heart valves (i.e., the aortic, pulmonary, tricuspid and mitral valves) serve critical functions in assuring the forward flow of an adequate supply of blood through the cardiovascular system. These heart valves can be damaged, and thus rendered less effective, by congenital malformations, inflammatory processes, infectious conditions, or disease. Such damage to the valves can result in serious cardiovascular compromise or death. For many years the definitive treatment for such damaged valves was surgical repair or replacement of the valve during open heart surgery. However, open heart surgeries are highly invasive and are prone to many complications. Therefore, elderly and frail patients with defective heart valves often went untreated. More recently, transvascular techniques have been developed for introducing and implanting prosthetic devices in a manner that is much less invasive than open heart surgery. One particular transvascular technique that is used for accessing the native mitral and aortic valves is the transseptal technique. The transseptal technique comprises inserting a catheter into the right femoral vein, up the inferior vena cava and into the right atrium. The septum is then punctured and the catheter passed into the left atrium where a procedure can be performed within the left side of the heart. Such transvascular techniques have increased in popularity due to their high success rates.

A healthy heart has a generally conical shape that tapers to a lower apex. The heart is four-chambered and comprises the left atrium, right atrium, left ventricle, and right ventricle. The left and right sides of the heart are separated by a wall generally referred to as the septum. The native mitral valve of the human heart connects the left atrium to the left ventricle. The mitral valve has a very different anatomy than other native heart valves. The mitral valve includes an annulus portion, which is an annular portion of the native valve tissue surrounding the mitral valve orifice, and a pair of cusps, or leaflets, extending downward from the annulus into the left ventricle. The mitral valve annulus can form a “D”-shaped, oval, or otherwise out-of-round cross-sectional shape having major and minor axes. The anterior leaflet can be larger than the posterior leaflet, forming a generally “C”-shaped boundary between the abutting free edges of the leaflets when they are closed together.

When operating properly, the anterior leaflet and the posterior leaflet function together as a one-way valve to allow blood to flow only from the left atrium to the left ventricle. The left atrium receives oxygenated blood from the pulmonary veins. When the muscles of the left atrium contract and the left ventricle dilates (also referred to as “ventricular diastole” or “diastole”), the oxygenated blood that is collected in the left atrium flows into the left ventricle. When the muscles of the left atrium relax and the muscles of the left ventricle contract (also referred to as “ventricular systole” or “systole”), the increased blood pressure in the left ventricle urges the two leaflets together, thereby closing the one-way mitral valve so that blood cannot flow back to the left atrium and is instead expelled out of the left ventricle through the aortic valve. To prevent the two leaflets from prolapsing under pressure and folding back through the mitral annulus toward the left atrium, a plurality of fibrous cords called chordae tendineae tether the leaflets to papillary muscles in the left ventricle.

Mitral regurgitation occurs when the native mitral valve fails to close properly and blood flows into the left atrium from the left ventricle during the systolic phase of heart contraction. Mitral regurgitation is the most common form of valvular heart disease. Mitral regurgitation has different causes, such as leaflet prolapse, dysfunctional papillary muscles and/or stretching of the mitral valve annulus resulting from dilation of the left ventricle. Mitral regurgitation at a central portion of the leaflets can be referred to as central jet mitral regurgitation and mitral regurgitation nearer to one commissure (i.e., location where the leaflets meet) of the leaflets can be referred to as eccentric jet mitral regurgitation.

Some prior techniques for treating mitral regurgitation include stitching portions of the native mitral valve leaflets directly to one another. Other prior techniques include the use of a spacer implanted between the native mitral valve leaflets. Despite these prior techniques, there is a continuing need for improved devices and methods for treating mitral valve regurgitation.

SUMMARY

Described herein are embodiments of prosthetic devices that are primarily intended to be implanted at one of the mitral, aortic, tricuspid, or pulmonary valve regions of a human heart, as well as apparatuses and methods for implanting the same. The prosthetic devices can be used to help restore and/or replace the functionality of a defective native valve.

An implantable prosthetic device can include one or more inflatable spacers and a frame having one or more anchors. The inflatable spacer can be configured to be disposed between native leaflets of a heart. The anchors can be coupled to the inflatable spacer and can be configured to secure the native leaflets against the inflatable spacer.

In some embodiments, the frame can further comprise a plurality of clasps. The clasps can be coupled to a respective anchor and configured to secure the native leaflets to the anchors. The clasps can be independently movable between an open configuration and a closed configuration.

In one representative embodiment, an implantable prosthetic device comprises an inflatable spacer having an interior cavity, the inflatable spacer being inflatable between an uninflated configuration and an inflated configuration, wherein in the inflated configuration the inflatable spacer is configured to be positioned between native heart valve leaflets to reduce regurgitation therebetween; and a frame comprising at least one anchor configured to be placed on one side of one of the native leaflets, and a clasp coupled to the anchor and configured to be placed on the other side of the one native leaflet, wherein the clasp is moveable between an open position and a closed position, wherein when in the closed position the clasp is configured to retain a portion of the one native leaflet to the anchor, and wherein the inflatable spacer is configured to be inflated from the uninflated configuration to the inflated configuration by filling the interior cavity of the inflatable spacer with an inflation medium or inflation media.

In some embodiments, the inflatable spacer is a balloon or other type of inflatable or fillable element (e.g., a cloth pocket). In such embodiments, the inflatable spacer can be inflatable between an uninflated configuration and a fully or partially inflated configuration. In certain embodiments, the inflatable spacer can be inflated by inflating an interior cavity of the inflatable spacer with an inflation medium or inflation media. The inflation medium can be a fluid and/or a non-fluid. Various fluids can be used such as saline solution, epoxy, blood, and/or other fluid configured for inflating. In some embodiments, the fluid can be a gaseous fluid, such as an inert gas (e.g., a gas that will not undergo chemical reactions, or at least undesired chemical reactions, with the body or components of the prosthetic spacer device under delivery conditions or after implantation). Suitable gasses can include nitrogen, carbon dioxide, helium, and argon, including mixtures thereof. Other gases, such as oxygen, may be included in mixtures of gases, such as air. The non-fluid can, for example, be a plurality of microbeads, a plurality of pellets, and/or other non-fluid medium configured for inflating. In some embodiments, both fluid and non-fluid media may be used in combination to inflate the inflatable spacer.

In some embodiments, the implantable prosthetic device can further comprise a source of the inflation medium. In some embodiments, the inflation medium can be a saline solution. In other embodiments, the inflatable spacer can be configured to receive blood to inflate the inflatable spacer from the uninflated configuration to the inflated configuration.

In some embodiments, the inflatable spacer can comprise a plurality of inflatable members each having an interior cavity. The plurality of inflatable members can be distinct structures or can be a single structure having a plurality of chambers. The inflatable members can be individually moveable between a fully or partially inflated configuration and an uninflated configuration. The inflatable members can be inflated in a symmetrical configuration or in an asymmetrical configuration.

In some embodiments, the inflatable spacer can comprise first and second inflatable members. In such embodiments, the asymmetrical configuration can comprise inflating, for example, the first inflatable member to the fully inflated configuration and leaving the second inflatable member in the uninflated configuration. The symmetrical configuration can comprise, for example, inflating both the first and second inflatable members to the fully inflated configuration.

In some embodiments, the inflatable spacer can have a substantially cylindrical shape (i.e. having a round cross-sectional shape taken in a plane perpendicular to an axis extending from the proximal end portion to the distal end portion of the prosthetic spacer device). In other embodiments, the inflatable spacer can be substantially rectangular, annular, semi-circular, or have another shape configured to create a surface against which the native leaflets can coapt. In some embodiments, the inflatable spacer can be a non-uniform shape configured to fill a space between improperly functioning native leaflets that do not coapt completely. In some embodiments, the inflatable spacer can have tapered end portions.

In some embodiments, the inflatable spacer can comprise one or more inflation valves through which inflation media can enter and/or exit the interior cavity of the inflatable spacer and/or the interior cavities of the inflatable members and either inflate or deflate the inflatable spacer and/or the inflatable members.

In some embodiments, the inflation valve can be a slit valve. The slit valve can have a flexible annular seal through which an inflation shaft of the delivery system can extend. When the inflation shaft is removed from the flexible annular seal the seal can bias closed, preventing any inflation medium from exiting and/or entering the interior cavity of the inflatable spacer.

In other embodiments, the inflation valve can be a check valve. The check valve can be configured to prevent inflation medium from entering the interior cavity of the inflatable spacer if the pressure external to the check valve is greater than the opening (or “cracking”) pressure of the check valve. If the external pressure is greater than the cracking pressure of the check valve, the valve will open and allow media to enter the interior cavity of the inflatable spacer.

In other embodiments, the inflation valve may be a ball valve, a diaphragm valve, a swing valve, an in-line valve, or other type of valve.

In some embodiments, the inflatable spacer can be formed from various materials, including polymers such as nylon, polyesters, polypropylenes, polytetrafluoroethylene, expanded polytetrafluoroethylene, silicone, urethane, and poly-carbonate-based and/or polyether-based thermoplastic polyurethanes (TPU).

In some embodiments, the interior cavity of the inflatable spacer can contain a matrix material. For example, the interior cavity can contain a gel foam, a sponge, a clotting agent, hemostatic matrices, and/or spun collagen hemostatic granules. In such embodiments, the matrix material may expand and/or solidify when contacted by the material used to expand the inflatable spacer.

In some embodiments, the implantable prosthetic device can further comprise a stretchable cover covering an external surface of the inflatable spacer. The stretchable cover can comprise a material configured to promote tissue ingrowth. In other embodiments, in lieu of or in addition to the material configured to promote tissue ingrowth the stretchable cover can comprise a material configured to delay or prevent tissue ingrowth. In some embodiments, the cover can be elastic. In other embodiments, the inflatable spacer can be non-elastic and the cover can stretch in at least one direction upon inflation of one of the inflatable members.

In some embodiments, the inflatable spacer of the implantable prosthetic device can comprise a longitudinal axis extending from an upstream end to a downstream end of the spacer and the spacer can be configured form an asymmetric shape with respect to the longitudinal axis when the spacer is at least partially inflated.

In another representative embodiment, an implantable prosthetic device can comprise an inflatable spacer configured to be positioned between native heart valve leaflets to reduce regurgitation therebetween, the spacer comprising a plurality of inflatable members each having an interior cavity, each inflatable member being inflatable between an uninflated configuration and an inflated configuration, and at least one anchor configured to anchor the inflatable spacer relative to the native leaflet, wherein each inflatable member can be independently inflated to a respective inflated configuration.

In some embodiments, the plurality of inflatable members can comprise a first inflatable member and a second inflatable member. The first and second inflatable members can be different sizes and/or shapes when fully inflated.

In some embodiments, the inflatable spacer can form an asymmetric shape when the inflatable members are inflated with different amounts of an inflation medium.

In some embodiments, the plurality of inflatable members can comprise first and second inflatable members that extend radially outwardly from a central longitudinal axis of the spacer on diametrically opposed sides of the longitudinal axis. In some embodiments, each inflatable member can comprise first and second, opposed major surfaces that are configured to coapt with the native leaflets when the spacer is implanted between the leaflets, each inflatable member having a width measured from the first major surface to the second major surface, and each inflatable member is configured to increase in width as it inflated.

In some embodiments, the inflatable spacer can comprise first and second media pathways. The first media pathway can be adapted to receive a pressurized inflation medium and allow the medium to flow into the first inflatable member, and the second media pathway can be adapted to receive the pressurized inflation medium and allow the medium to flow into the second inflatable member.

In some embodiments, the anchor of the inflatable prosthetic device can comprise at least two anchors configured to anchor onto the native leaflets.

In another representative embodiment, an implantable prosthetic device comprises an inflatable spacer, a plurality of anchors, and a plurality of clasps. The inflatable spacer is configured to be disposed between native leaflets of a heart. The anchors are coupled to the inflatable spacer and configured to anchor the inflatable spacer relative to the native leaflet. The clasps are configured to secure the native leaflets to the anchors and have fixed end portions and free end portions. The fixed end portions are coupled to the anchors. The free end portions have barbs. The free end portions are pivotable relative to the fixed end portions between an open configuration and a closed configuration. The free end portions are axially movable in the open configuration from a first position in which the barbs engage tissue of the native leaflets to a second position in which the barbs disengage the tissue of the native leaflets.

In another representative embodiment, an assembly comprises an implantable prosthetic spacer device and a delivery apparatus. The implantable prosthetic device has an inflatable spacer and a frame comprising a plurality of anchors, a plurality of clasps, a first collar, and a second collar. First end portions of the anchors are coupled to a first end portion of the inflatable spacer, and second end portions of the anchors are coupled to the first collar. The second collar is coupled to a second end portion of the inflatable spacer, and the clasps are coupled to the anchors. The delivery apparatus has a first shaft, a second shaft, and a plurality of clasp control members. The clasp control members are releasably coupled to the clasps of the prosthetic device. Actuating the clasp control members moves the clasps between an open configuration and a closed configuration.

In some embodiments, the delivery apparatus further comprises one or more inflation shafts for inflating the inflatable spacer and/or inflatable members. The inflation shafts are configured to releasably couple the inflatable spacer allowing medium used to inflate the inflatable spacer to enter the interior cavity thereof.

In some embodiments, the delivery apparatus further comprises a media source, and the inflation shafts can be releasably coupled to the media source. The media source can be configured to supply and/or retrieve a medium to inflate and/or deflate the inflatable spacer.

In some embodiments, the delivery apparatus is configured such that moving the first shaft and the second shaft relative to each other moves the prosthetic device between a first configuration, in which anchors are in a radially compressed, and a second configuration, in which the anchors are in a radially expanded, axially compressed configuration and at least partially overlap the inflatable spacer to capture native leaflets between the anchors and the inflatable spacer.

In some embodiments, the delivery apparatus further comprises a clasp control mechanism, and the clasp control members are releasably coupled to the clasp control mechanism. The clasp control mechanism is configured such that the clasp control members can be actuated either simultaneously or separately.

In another representative embodiment, an assembly comprises a prosthetic spacer device and a delivery apparatus. The delivery apparatus comprises an outer shaft, an actuation shaft, and a plurality of tethers. The outer shaft has a first lumen and a plurality of second lumens disposed radially outwardly from the first lumen. The actuation shaft extends through the first lumen. The actuation shaft is axially movable relative the outer shaft and releasably coupled to the prosthetic device. The tethers extend through the second lumens and are releasably coupled to the prosthetic device. Tensioning the tethers moves the implantable prosthetic device and the outer shaft toward each other. Slackening the tethers allows the implantable prosthetic device and the outer shaft to be spaced apart from each other.

In some embodiments, each of the tethers is disposed in two of the second lumens that are circumferentially offset by approximately 180 degrees.

In some embodiments, the prosthetic spacer device further comprises a plurality of clasps. The clasps are coupled to a respective anchor and are configured to secure the native leaflets to the anchors. The clasps are movable between an open configuration and a closed configuration. The outer shaft of the delivery apparatus further comprises a plurality of third lumens disposed radially outwardly from the first lumen. The delivery apparatus further comprises a plurality of control members extending through the third lumens and releasably coupled to the clasps of the prosthetic device. Tensioning the control members moves the clasps to the open configuration. Slackening the control members allows the clasps to move to the closed configuration.

In some embodiments, each of the control members is disposed in two of the third lumens that are circumferentially offset by approximately 180 degrees.

In another representative embodiment, an assembly comprises an implantable prosthetic spacer device and a delivery apparatus. The implantable prosthetic spacer device has an inflatable spacer comprising a plurality of inflatable members, a plurality of anchors, a plurality of clasps, a first collar, and a second collar. The first end portions of the anchors are coupled to a first end portion of the inflatable spacer, and second end portions of the anchors are coupled to the first collar. The second collar is coupled to a second end portion of the inflatable spacer, and the clasps are coupled to the anchors and are independently movable between an open configuration and a closed configuration. The delivery apparatus has a first shaft, a second shaft, a plurality of tethers, and a plurality of clasp control members. The first shaft is releasably coupled to the first collar of the prosthetic device by the tethers, the second shaft is releasably coupled to the second collar of the prosthetic device, and the clasp control members are releasably coupled to the clasps of the prosthetic device. Actuating the clasp control members moves the clasps between an open configuration and a closed configuration. Tensioning the tethers moves the prosthetic device and the first shaft toward each other, and slackening the tethers allows the prosthetic device and the first shaft to be spaced from each other.

In a representative embodiment, a method for implanting a prosthetic spacer device to improve coaptation of native heart valve leaflets can comprise advancing a delivery apparatus and an implantable prosthetic device into a body of a patient, the implantable prosthetic device comprising an inflatable spacer comprising at least first and second inflatable members. Positioning the inflatable spacer between the native heart valve leaflets, and at least partially inflating at least the first inflatable member with an inflation medium so that the spacer assumes an asymmetric configuration against which the native leaflets can coapt.

In some embodiments, the method can further comprise anchoring the prosthetic device against tissue in the heart with an anchor of the prosthetic device so as to support the spacer between the native leaflets.

In some embodiments, the asymmetric configuration of the spacer can be asymmetric with respect to a central longitudinal axis of the spacer that extends from an upstream end to a downstream end of the spacer. In some embodiments, the asymmetric configuration can be asymmetric with respect to a lateral axis of the spacer. In some embodiments, the method can further comprise inflating the second inflatable member to create a symmetric configuration against which the native leaflets can coapt.

The various innovations of this disclosure can be used in combination or separately. This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. The foregoing and other objects, features, and advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.

