Anti-paravalvular leakage components for a transcatheter valve prosthesis

A valve prosthesis includes one or more anti-paravalvular leakage components coupled to a stent. The anti-paravalvular leakage component may encircle the stent and include a radially expandable control ring coupled to an unattached edge of a flexible skirt which extends the unattached skirt edge outwardly away from the stent and against the native heart valve to form an open-ended annular pocket around the stent. The anti-paravalvular leakage component may encircle the perimeter of the stent and include a flexible skirt having opposing edges coupled to the stent to form one or more enclosed compartments around the stent. Each compartment includes a one-way valve which allows for blood flow into the compartment but prevents blood flow out of the compartment. The anti-paravalvular leakage component may be at least one flap that is coupled to an inner surface of the stent and formed of a flexible material moveable by blood flow.

FIELD OF THE INVENTION

The present invention relates to transcatheter valve prostheses and one or more anti-paravalvular leakage components formed on a surface of a transcatheter valve prosthesis for preventing paravalvular leakage.

BACKGROUND OF THE INVENTION

A human heart includes four heart valves that determine the pathway of blood flow through the heart: the mitral valve, the tricuspid valve, the aortic valve, and the pulmonary valve. The mitral and tricuspid valves are atrioventricular valves, which are between the atria and the ventricles, while the aortic and pulmonary valves are semilunar valves, which are in the arteries leaving the heart. Ideally, native leaflets of a heart valve move apart from each other when the valve is in an open position, and meet or “coapt” when the valve is in a closed position. Problems that may develop with valves include stenosis in which a valve does not open properly, and/or insufficiency or regurgitation in which a valve does not close properly. Stenosis and insufficiency may occur concomitantly in the same valve. The effects of valvular dysfunction vary, with regurgitation or backflow typically having relatively severe physiological consequences to the patient.

Recently, flexible prosthetic valves supported by stent structures that can be delivered percutaneously using a catheter-based delivery system have been developed for heart and venous valve replacement. These prosthetic valves may include either self-expanding or balloon-expandable stent structures with valve leaflets attached to the interior of the stent structure. The prosthetic valve can be reduced in diameter, by crimping onto a balloon catheter or by being contained within a sheath component of a delivery catheter, and advanced through the venous or arterial vasculature. Once the prosthetic valve is positioned at the treatment site, for instance within an incompetent native valve, the stent structure may be expanded to hold the prosthetic valve firmly in place. One example of a stented prosthetic valve is disclosed in U.S. Pat. No. 5,957,949 to Leonhardt et al. entitled “Percutaneous Placement Valve Stent”, which is incorporated by reference herein in its entirety. Another example of a stented prosthetic valve for a percutaneous pulmonary valve replacement procedure is described in U.S. Patent Application Publication No. 2003/0199971 A1 and U.S. Patent Application Publication No. 2003/0199963 A1, both filed by Tower et al., each of which is incorporated by reference herein in its entirety.

Although transcatheter delivery methods have provided safer and less invasive methods for replacing a defective native heart valve, leakage between the implanted prosthetic valve and the surrounding native tissue is a recurring problem. Leakage sometimes occurs due to the fact that minimally invasive and percutaneous replacement of cardiac valves typically does not involve actual physical removal of the diseased or injured heart valve. Rather, the replacement stented prosthetic valve is delivered in a compressed condition to the valve site, where it is expanded to its operational state within the mitral valve. Calcified or diseased native leaflets are pressed to the side walls of the native valve by the radial force of the stent frame of the prosthetic valve. These calcified leaflets do not allow complete conformance of the stent frame with the native valve and can be a source of paravalvular leakage (PVL). Significant pressure gradients across the valve cause blood to leak through the gaps between the implanted prosthetic valve and the calcified anatomy.

Embodiments hereof are related to anti-paravalvular leakage components coupled to the valve prosthesis to prevent paravalvular leakage.

BRIEF SUMMARY OF THE INVENTION

Embodiments hereof relate to a transcatheter valve prosthesis including a tubular stent having a compressed configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve, a prosthetic valve component disposed within and secured to the stent, and an anti-paravalvular leakage component coupled to and encircling an outer surface of the tubular stent. The anti-paravalvular leakage component includes a skirt formed of a flexible material. The skirt has a first edge coupled to the tubular stent and an opposing second edge not coupled to the tubular stent. A radially expandable control ring is coupled to the second edge of the skirt. The control ring in an expanded diameter extends the second edge of the skirt outwardly away from the outer surface of the tubular stent and against the native heart valve to form an open-ended annular pocket between the skirt and the outer surface of the tubular stent.

According to another embodiment hereof, a transcatheter valve prosthesis includes a tubular stent having a compressed configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve, a prosthetic valve component disposed within and secured to the stent, and an anti-paravalvular leakage component coupled to and encircling an outer surface of the tubular stent. The anti-paravalvular leakage component includes a skirt formed of a flexible material. The skirt has a first edge coupled to the tubular stent and an opposing second edge not coupled to the tubular stent. A control ring having an adjustable diameter is coupled to the second edge of the skirt. The diameter of the control ring may be varied in situ to selectively extend the second edge of the skirt outwardly away from the outer surface of the tubular stent and against the native heart valve.

According to another embodiment hereof, a transcatheter valve prosthesis includes a tubular stent having a compressed configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve, a prosthetic valve component disposed within and secured to the stent, and an anti-paravalvular leakage component coupled to an inner surface of the tubular stent. The anti-paravalvular leakage component includes at least one flap formed of a flexible material moveable by blood flow. The flap has a first end coupled to the tubular stent adjacent to prosthetic valve component and an opposing second end not coupled to the tubular stent.

According to another embodiment hereof, a transcatheter valve prosthesis includes a tubular stent having a compressed configuration for delivery within a vasculature and an expanded configuration for deployment within a native heart valve, a prosthetic valve component disposed within and secured to the stent, and an anti-paravalvular leakage component coupled to and encircling an outer surface of the tubular stent. The anti-paravalvular leakage component includes a skirt formed of a flexible material. The skirt has first and second opposing edges coupled to the tubular stent to form one or more enclosed compartments between the skirt and the outer surface of the tubular stent. Each enclosed compartment includes a one-way valve which allows for blood flow into the compartment but prevents blood flow out of the compartment.

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the present invention are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. If utilized herein, the terms “distal” or “distally” refer to a position or in a direction away from the heart and the terms “proximal” and “proximally” refer to a position near or in a direction toward the heart. The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Although the description of the invention is in the context of treatment of heart valves, the invention may also be used where it is deemed useful in other valved intraluminal sites that are not in the heart. For example, the present invention may be applied to venous valves as well. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.

FIG. 1depicts an exemplary transcatheter heart valve prosthesis100. Heart valve prosthesis100is illustrated herein in order to facilitate description of the methods and devices to prevent and/or repair paravalvular leakage according to embodiments hereof. It is understood that any number of alternate heart valve prostheses can be used with the methods and devices described herein. Heart valve prosthesis100is merely exemplary and is described in more detail in U.S. Patent Application Pub. No. 2011/0172765 to Nguyen et al., which is herein incorporated by reference in its entirety.

Heart valve prosthesis100includes an expandable stent or frame102that supports a prosthetic valve component within the interior of stent102. In embodiments hereof, stent102is self-expanding to return to an expanded deployed state from a compressed or constricted delivery state and may be made from stainless steel, a pseudo-elastic metal such as a nickel titanium alloy or Nitinol, or a so-called super alloy, which may have a base metal of nickel, cobalt, chromium, or other metal. “Self-expanding” as used herein means that a structure/component has a mechanical memory to return to the expanded or deployed configuration. Mechanical memory may be imparted to the wire or tubular structure that forms stent102by thermal treatment to achieve a spring temper in stainless steel, for example, or to set a shape memory in a susceptible metal alloy, such as nitinol, or a polymer, such as any of the polymers disclosed in U.S. Pat. Appl. Pub. No. 2004/0111111 to Lin, which is incorporated by reference herein in its entirety. Alternatively, heart valve prosthesis100may be balloon-expandable as would be understood by one of ordinary skill in the art.

In the embodiment depicted inFIGS. 1 and 1A, stent102of valve prosthesis100has a deployed asymmetric hourglass configuration including an enlarged first end or section116, a constriction or waist region117, and a second end or section118. Enlarged first section116has nominal deployed diameter D1, second section118has nominal deployed diameter D2, and constriction region117has deployed substantially fixed diameter D3. Each section of stent102may be designed with a number of different configurations and sizes to meet the different requirements of the location in which it may be implanted. When configured as a replacement for an aortic valve, second section118functions as an inflow end of heart valve prosthesis100and extends into and anchors within the aortic annulus of a patient's left ventricle, while first section116functions as an outflow end of heart valve prosthesis100and is positioned in the patient's ascending aorta. When configured as a replacement for a mitral valve, enlarged first section116functions as an inflow end of heart valve prosthesis100and is positioned in the patient's left atrium, while second section118functions as an outflow end of heart valve prosthesis100and extends into and anchors within the mitral annulus of a patient's left ventricle. For example, U.S. Patent Application Publication Nos. 2012/0101572 to Kovalsky et al. and 2012/0035722 to Tuval, each of which are herein incorporated by reference in their entirety, illustrate heart valve prostheses configured for placement in a mitral valve. Each section of stent102may have the same or different cross-section which may be for example circular, ellipsoidal, rectangular, hexagonal, rectangular, square, or other polygonal shape, although at present it is believed that circular or ellipsoidal may be preferable when the valve prosthesis is being provided for replacement of the aortic or mitral valve. As alternatives to the deployed configuration ofFIGS. 1 and 1A, the stent/valve support frame may have an hourglass configuration102B shown inFIG. 1B, a generally tubular configuration102C as shown inFIG. 1C, or other stent configuration or shape known in the art for valve replacement. Stent102also may include eyelets108that extend from first end116thereof for use in loading the heart valve prosthesis100into a delivery catheter (not shown).

As previously mentioned, heart valve prosthesis100includes a prosthetic valve component within the interior of stent102. The prosthetic valve component is capable of blocking flow in one direction to regulate flow there through via valve leaflets104that may form a bicuspid or tricuspid replacement valve.FIG. 1Ais an end view ofFIG. 1and illustrates an exemplary tricuspid valve having three leaflets104, although a bicuspid leaflet configuration may alternatively be used in embodiments hereof. More particularly, if heart valve prosthesis100is configured for placement within a native valve having three leaflets such as the aortic, tricuspid, or pulmonary valves, heart valve prosthesis100includes three valve leaflets104. If heart valve prosthesis100is configured for placement within a native valve having two leaflets such as the mitral valve, heart valve prosthesis100includes two valve leaflets104. Valve leaflets104are sutured or otherwise securely and sealingly attached to the interior surface of stent102and/or graft material106which encloses or lines a portion of stent102as would be known to one of ordinary skill in the art of prosthetic tissue valve construction. Referring toFIG. 1, leaflets104are attached along their bases110to graft material106, for example, using sutures or a suitable biocompatible adhesive. Adjoining pairs of leaflets are attached to one another at their lateral ends to form commissures120, with free edges122of the leaflets forming coaptation edges that meet in area of coaptation114.

Leaflets104may be made of pericardial material; however, the leaflets may instead be made of another material. Natural tissue for replacement valve leaflets may be obtained from, for example, heart valves, aortic roots, aortic walls, aortic leaflets, pericardial tissue, such as pericardial patches, bypass grafts, blood vessels, intestinal submucosal tissue, umbilical tissue and the like from humans or animals. Synthetic materials suitable for use as leaflets104include DACRON® polyester commercially available from Invista North America S.A.R.L. of Wilmington, Del., other cloth materials, nylon blends, polymeric materials, and vacuum deposition nitinol fabricated materials. One polymeric material from which the leaflets can be made is an ultra-high molecular weight polyethylene material commercially available under the trade designation DYNEEMA from Royal DSM of the Netherlands. With certain leaflet materials, it may be desirable to coat one or both sides of the leaflet with a material that will prevent or minimize overgrowth. It is further desirable that the leaflet material is durable and not subject to stretching, deforming, or fatigue.

Graft material106may also be a natural or biological material such as pericardium or another membranous tissue such as intestinal submucosa. Alternatively, graft material106may be a low-porosity woven fabric, such as polyester, Dacron fabric, or PTFE, which creates a one-way fluid passage when attached to the stent. In one embodiment, graft material106may be a knit or woven polyester, such as a polyester or PTFE knit, which can be utilized when it is desired to provide a medium for tissue ingrowth and the ability for the fabric to stretch to conform to a curved surface. Polyester velour fabrics may alternatively be used, such as when it is desired to provide a medium for tissue ingrowth on one side and a smooth surface on the other side. These and other appropriate cardiovascular fabrics are commercially available from Bard Peripheral Vascular, Inc. of Tempe, Ariz., for example. In one embodiment shown inFIG. 1, graft material106extends from leaflets bases110to second end118of heart valve prosthesis.

Delivery of heart valve prosthesis100may be accomplished via a percutaneous transfemoral approach or a transapical approach directly through the apex of the heart via a thoracotomy, or may be positioned within the desired area of the heart via different delivery methods known in the art for accessing heart valves. During delivery, if self-expanding, the prosthetic valve remains compressed until it reaches a target diseased native heart valve, at which time the heart valve prosthesis100can be released from the delivery catheter and expanded in situ via self-expansion. The delivery catheter is then removed and heart valve prosthesis100remains deployed within the native target heart valve. Alternatively, heart valve prosthesis100may be balloon-expandable and delivery thereof may be accomplished via a balloon catheter as would be understood by one of ordinary skill in the art.

FIG. 2is a side view illustration of heart valve prosthesis100implanted within a native aortic heart valve, which is shown in section, having native leaflets LNand corresponding native sinuses SN. When heart valve prosthesis100is deployed within the valve annulus of a native heart valve, stent102expands within native valve leaflets LNof the patient's defective valve, retaining the native valve leaflets in a permanently open state. The native valve annulus may include surface irregularities on the inner surface thereof, and as a result one or more gaps or cavities/crevices226may be present or may form between the perimeter of heart valve prosthesis100and the native valve annulus. For example, calcium deposits may be present on the native valve leaflets (e.g., stenotic valve leaflets) and/or shape differences may be present between the native heart valve annulus and prosthesis100. More particularly, in some cases native annuli are not perfectly rounded and have indentations corresponding to the commissural points of the native valve leaflets. As a result, a prosthesis having an approximately circular shape does not provide an exact fit in a native valve. These surface irregularities, whatever their underlying cause, can make it difficult for conventional prosthetic valves to form a blood tight seal between the prosthetic valve and the inner surface of the valve annulus, causing undesirable paravalvular leakage and/or regurgitation at the implantation site.

Embodiments hereof relate to methods for delivering a heart valve prosthesis having a anti-paravalvular leakage component coupled to and encircling an outer surface of the heart valve prosthesis in order to occlude or fill gaps between the perimeter of a heart valve prosthesis and the native valve annulus, thereby reducing, minimizing, or eliminating leaks there through. More particularly, with reference toFIG. 3andFIG. 4, an anti-paravalvular leakage component330includes a skirt332formed of a flexible material and a radially expandable control ring334. Skirt332is a flap having has a first end or edge coupled to stent102and an opposing second end or edge not coupled to stent102. As used herein, a flap is a moveable piece of flexible material that has at least a portion of the first edge attached to stent102. The first end or edge of skirt332may be attached to stent102by any suitable means known to those skilled in the art, for example and not by way of limitation, welding, adhesive, suture, or mechanical coupling. As will be explained in more detail herein, expandable control ring334is coupled to the second or unattached edge of skirt332and operates to radially extend or deploy the unattached edge of skirt332outwardly away from stent102to form an open-ended annular pocket or compartment336between an inner surface of the skirt and the outer surface of the tubular stent. Open-ended pocket336catches and blocks any retrograde flow within the native valve, thereby preventing undesired regurgitation and preventing blood stagnation in and around the native valve sinuses. In addition, when deployed, anti-paravalvular leakage component330radially expands into and substantially fills any/all gaps or cavities/crevices between outer surface103of stent102and native valve tissue. “Substantially” as utilized herein means that blood flow through the target gap or cavity is occluded or blocked, or stated another way blood is not permitted to flow there through. Anti-paravalvular leakage component330functions as a continuous circumferential seal around heart valve prosthesis100to block or prevent blood flow around the outer perimeter of the prosthesis, thereby minimizing and/or eliminating any paravalvular leakage at the implantation site.

Although embodiments depicted herein illustrate open-ended annular pocket336of anti-paravalvular leakage component330oriented to catch retrograde blood flow, it would be obvious to one of ordinary skill in the art that pocket336may be inverted to catch antegrade flow rather than retrograde flow. More particularly, open-ended annular pocket336can be oriented in the opposite direction (i.e., to prevent forward blood flow), with its open side facing generally towards second end118of heart valve prosthesis rather than facing generally towards first end116of heart valve prosthesis.

In the embodiment ofFIGS. 3-4, anti-paravalvular leakage component330is coupled to outer surface103of heart valve prosthesis100along constriction region117thereof, described with respect toFIG. 1above. When deployed, anti-paravalvular leakage component330may be positioned in situ at the native valve annulus, slightly above the valve annulus, slightly below the valve annulus, or some combination thereof. Since the annular anti-paravalvular leakage component is coupled to outer surface103of heart valve prosthesis100, longitudinal placement and/or the size and shape thereof is flexible and may be adjusted or adapted according to each application and to a patient's unique needs. For example, depending on the anatomy of the particular patient, the anti-paravalvular leakage component may be positioned on heart valve prosthesis100so that in situ the anti-paravalvular leakage component is positioned between heart valve prosthesis100and the interior surfaces of the native valve leaflets, between heart valve prosthesis100and the interior surfaces of the native valve annulus, and/or between heart valve prosthesis100and the interior surfaces of the left ventricular outflow track (LVOT).

Suitable materials for skirt332include but are not limited to a low-porosity woven fabric such as polyester, Dacron fabric, or PTFE. Porous materials advantageously provide a medium for tissue ingrowth. Further, skirt332may be pericardial tissue or may be a knit or woven polyester, such as a polyester or polytetrafluoroethylene (PTFE) knit, both of which provide a medium for tissue ingrowth and have the ability to stretch to conform to a curved surface. Polyester velour fabrics may alternatively be used, such as when it is desired to provide a medium for tissue ingrowth on one side and a smooth surface on the other side. Elastomeric materials such as but not limited to polyurethane may also be used as a material for skirt332.

Skirt332may include an integral folded portion which essentially creates two layers or a double layer of fabric that extends over a portion of the outer surface of stent102. More particularly, as shown in the embodiment ofFIG. 5A, a first edge538A of skirt332A is attached or coupled to outer surface103of stent102along constriction region117thereof, described with respect toFIG. 1above. A portion540of skirt332A abuts against outer surface103of stent102and extends over stent102in a direction towards second end118, creating an inner layer of skirt material. In an embodiment, portion540may be attached to stent102by any suitable means known to those skilled in the art, for example and not by way of limitation, welding, adhesive, suture, or mechanical coupling. In another embodiment, portion540may be unattached to stent102. Skirt332A includes an integral fold541in the skirt material such that the remainder of skirt332A bends over itself and extends in a direction towards first end116, thereby creating an outer layer of skirt material that extends over stent102. Fold541may be attached to stent102or may be unattached to stent102. A second edge539A of skirt332B is unattached to stent102and coupled to control ring334(not shown inFIG. 5A) so that when control ring334/second edge539A is radially extended, the outer layer of skirt material is spaced apart from outer surface103of stent102and open-ended annular pocket336is formed between the inner and outer layers of skirt material.

In another embodiment hereof, skirt332may include only a single layer of fabric that extends over a portion of the outer surface of stent102. More particularly, as shown in the embodiment ofFIG. 5B, a first edge538B of skirt332B is attached or coupled to outer surface103of stent102adjacent to second end118thereof. Skirt332A extends in a direction towards first end116of stent102. A second edge539B of skirt332B is unattached to stent102and coupled to control ring334(not shown inFIG. 5B) so that when control ring334/second edge539B is radially extended, the single layer skirt332B is spaced apart from outer surface103of stent102and open-ended annular pocket336is formed between skirt332and stent102.

With additional reference toFIGS. 6A and 6B, ring334operates in situ to radially expand or extend free or unattached second edge of skirt332outwardly away from valve prosthesis and thereby form open-ended annular pocket336. As shown inFIG. 6A, in a first configuration, ring334has a first diameter D1which is approximately equal to an expanded diameter of heart valve prosthesis100. Ring334expands to a second diameter D2, which is larger than first diameter D1, during or after deployment of heart valve prosthesis100as shown inFIG. 6B. Second diameter D2is greater than an expanded diameter of heart valve prosthesis100so that when ring334expands to second diameter D2, it radially extends the second unattached edge of skirt332outwardly away from the outer surface of the heart valve prosthesis and forms open-ended annular pocket336.

In an embodiment, ring334is formed from a self-expanding material that returns to an expanded deployed state in which the diameter of ring334is second diameter D2from a compressed or constricted delivery state. The diameter of ring334in the compressed or constricted delivery state is approximately equal to the compressed or constricted delivery diameter of stent102. “Self-expanding” as used herein means that a structure/component has a mechanical memory to return to the expanded or deployed configuration. Mechanical memory may be imparted to the wire or tubular structure that forms ring334by thermal treatment to achieve a spring temper in stainless steel, for example, or to set a shape memory in a susceptible metal alloy, such as nitinol, or a polymer. Accordingly, ring334may be made from stainless steel, a pseudo-elastic metal such as a nickel titanium alloy or Nitinol, or a so-called super alloy, which may have a base metal of nickel, cobalt, chromium, or other metal.

In another embodiment hereof, the control ring has an adjustable diameter that may be varied in situ to selectively extend the second unattached edge of skirt332outwardly away from the outer surface of the heart valve prosthesis. For example,FIGS. 7 and 8illustrate an embodiment of a control ring734having an adjustable diameter that may be varied in situ. More particularly, an elongated strand750has a first end752and a second end754. Elongated strand750extends through a lumen of a delivery system (not shown) such that first end752of elongated strand750extends to a position outside of the body. Second end754of elongated strand750is slidingly positioned over a body of strand750via a series of interlocking teeth758A,758B and forms or divides strand750into control ring734and a tether or remainder756. As shown in the enlarged view ofFIG. 8, teeth758A are formed on a first surface of strand750and teeth758B are formed on a second surface of strand750that abuts against the first surface when a portion of strand750is formed or shaped into control ring734. Teeth758A,758B mate or interlock together in a male/female relationship. First end752of strand750is pushed or pulled to ratchet or move teeth758A forward or backward, respectively, over teeth758B and thereby expand or contract the diameter of control ring734.

Strand750includes at least one weakened area or break point that breaks or splits apart when force is applied thereto. The weakened area may be of various constructions as illustrated inFIGS. 5A-5F. InFIG. 9A, a weakened area960A is formed via a short segment of strand750having a smaller diameter than the remaining length of strand750. InFIG. 9B, a weakened area960B is formed via a perforations or serrations962. Perforations or serrations962include a series of holes in the form of one or more lines provided by perforating a short segment of strand750. Although a straight line of perforations962is shown inFIG. 9B, a wavy or zig-zag pattern of perforations may be utilized without departing from the scope of the present invention. In addition, although perforations962are shown as a series of longitudinal lines it would be understood by those of ordinary skill in the art that the lines may additionally and/or alternatively made in the radial direction. A weakened area960C may also include a slit, slot, or groove964as illustrated inFIG. 9C. Slit or slot964includes a straight cut, opening, or aperture in the form of one or more longitudinal lines provided by scoring or cutting strand750. Slit, slot, or groove964has a width that may be greater or equal to zero. In other words, slit, slot, or groove964may include a cut with approximately zero width or may include an opening or aperture with a narrow width. Slit, slot, or groove964may have a depth that extends from the inside surface to the outside surface of strand750, or alternatively may have a depth that extends only partially within the material of strand750.

Once the control ring is expanded to the desired diameter in situ, control ring734is disconnected from tether or remainder756via user-applied force that breaks or splits the weakened area apart. The user-applied force require to break the weakened area of strand750may include but not is not limited to twisting strand750, applying tension to strand750, and/or utilizing an external mechanism to pinch the weakened area of strand750. In one embodiment, strand750includes a plurality of weakened areas located between adjacent or abutting teeth758A (not shown onFIGS. 10A and 10B). When a user applies the required force to break apart a weakened area of strand750, control ring734is disconnected from tether or remainder756at the weakened area closest or nearest to the user which is not interlocked with teeth758B (not shown onFIGS. 10A and 10B). As such, as depicted inFIG. 10A, tether756may be removed from the patient and only control ring734remains in situ. In another embodiment depicted inFIG. 10B, strand750includes a single weakened area that is spaced apart from teeth758A (not shown onFIGS. 10A and 10B), located towards first end752. When a user applies the required force to break apart the weakened area of strand750, control ring734is disconnected from tether or remainder756at the weakened area and a relatively short tail or segment1062of strand750extending from control ring734remains in situ after tether756is removed from the patient.

In addition or as an alternative to an anti-paravalvular leakage component which extends around the perimeter of a heart valve prosthesis to prevent paravalvular leakage, a heart valve prosthesis may include an anti-paravalvular leakage component coupled to an inner surface of the heart valve prosthesis. More particularly, with reference toFIG. 11, heart valve prosthesis100is shown with a first anti-paravalvular leakage component330around the perimeter thereof and a second anti-paravalvular leakage component1170coupled to an inner surface thereof. Second anti-paravalvular leakage component1170includes a flap1172having has a first end or edge1174coupled to stent102and an opposing second end or edge1176not coupled to stent102. As used herein, a flap is a moveable piece of flexible material that has at least a portion of the first edge attached to stent102. The first end or edge of flap1172may be attached to stent102by any suitable means known to those skilled in the art, for example and not by way of limitation, sutures or a suitable biocompatible adhesive. In one embodiment depicted inFIG. 12A, flap1172is annular or donut-shaped and includes a plurality of radially-extending slits1178extending from second edge1176thereof. In another embodiment hereof, shown inFIG. 12B, anti-paravalvular leakage component1170B includes a plurality of adjacent flaps1172B each having a first end or edge1174B to be coupled to stent102(not shown inFIG. 12B) and an opposing second end or edge1176B which is not coupled to stent102. Flaps1172B are oriented around the inner surface of the stent such that a relatively small gap or space1178B extends between adjacent pairs of flaps1172B. AlthoughFIG. 12Billustrates anti-paravalvular leakage component1170B with four flaps1172B, it will be understood by one of ordinary skill in the art that four flaps is exemplary and a greater or lesser number of flaps may be utilized.

Flap1172is moveable by blood flow, i.e., in situ the flap is displaced in the direction of blood flow, and operates to cover open spaces1180of within tubular stent102which are not covered by graft material106in order to prevent blood flow from leaking through valve prosthesis100. More particularly, as described with respect toFIG. 1, in one embodiment hereof graft material106extends from the bases of leaflets104to second end118of heart valve prosthesis100but does not extend from the bases of leaflets104to first end116. Accordingly, inFIG. 1, blood may flow through or within the open spaces of stent102. However, in the embodiment ofFIG. 11, flap1172is located above leaflets104, closer to first end116of heart valve prosthesis100. Due to antegrade blood flow represented by arrow AFthrough heart valve prosthesis100, flap1172moves in a first direction indicated by directional arrow1182and is pressed against the inner surface of stent102to cover adjacent open spaces1180thereof. Similarly, due to retrograde blood flow represented by arrow RFthrough heart valve prosthesis100, flap1172moves in a second opposing direction indicated by directional arrow1184and is pressed against the inner surface of stent102to cover adjacent open spaces1180thereof. By covering opening spaces1180, blood flow is prevented or substantially reduced from flowing from inside heart valve prosthesis into any/all gaps or cavities/crevices between outer surface103of stent102and native valve tissue, thereby minimizing and/or eliminating any paravalvular leakage at the implantation site.

Suitable materials for flap1172include but are not limited to a low-porosity woven fabric, such as polyester, Dacron fabric, or PTFE. Porous materials advantageously provide a medium for tissue ingrowth. Further, flap1172may be pericardial tissue or may be a knit or woven polyester, such as a polyester or polytetrafluoroethylene (PTFE) knit, both of which have the ability to stretch to conform to a curved surface.

FIG. 13illustrates another embodiment hereof in which an anti-paravalvular leakage component is coupled to and encircles an outer surface of a heart valve prosthesis in order to occlude or fill gaps between the perimeter of a heart valve prosthesis and the native valve annulus, thereby reducing, minimizing, or eliminating leaks there through. More particularly, an anti-paravalvular leakage component1390includes a skirt1392formed of a flexible material that has first and second opposing edges1396,1398coupled to stent102to form one or more enclosed pockets or compartments between skirt1392and outer surface103of stent102. Stated another way, the enclosed pockets or compartments are closed or sealed via first and second opposing edges1396,1398of skirt being coupled to stent102. Edges1396,1398of skirt1392may be attached to stent102by any suitable means known to those skilled in the art, for example and not by way of limitation, welding, adhesive, suture, or mechanical coupling. As shown inFIG. 13, a plurality of dividers or seams1393may be provided on skirt1392to form a plurality of compartments positioned around stent102. The compartments can be formed in any number, size, and/or shape around stent102. Suitable materials for skirt1392include but are not limited to a low-porosity woven fabric, such as polyester, Dacron fabric, or PTFE. Porous materials advantageously provide a medium for tissue ingrowth. Further, skirt1392may be pericardial tissue or may be a knit or woven polyester, such as a polyester or polytetrafluoroethylene (PTFE) knit, both of which provide a medium for tissue ingrowth and have the ability to stretch to conform to a curved surface. Polyester velour fabrics may alternatively be used, such as when it is desired to provide a medium for tissue ingrowth on one side and a smooth surface on the other side.

Each pocket or compartment includes a one-way port or valve1394which allows for blood flow into the pocket but prevents blood flow out of the pocket. Examples of valve1394are described in more detail herein with respect toFIG. 14andFIGS. 15-16. In situ, blood flow between the perimeter of heart valve prosthesis100and the native valve annulus fills each pocket or compartment with blood. As each pocket or compartment fills with blood, skirt1392(which forms the outer surface of the pocket or compartment) radially or outwardly expands into and substantially fills any/all gaps or cavities/crevices between outer surface103of stent102and native valve tissue. “Substantially” as utilized herein means that blood flow through the target gap or cavity is occluded or blocked, or stated another way blood is not permitted to flow there through. Blood is essentially trapped within each pocket in order to prevent blood stagnation and form a seal. Anti-paravalvular leakage component1390functions as a seal for heart valve prosthesis100to block or prevent blood flow around the outer perimeter of the prosthesis, thereby minimizing and/or eliminating any paravalvular leakage at the implantation site.

In one embodiment shown inFIG. 14, the one-way port or valve is a membrane which allows flow in one direction therethrough. More particularly,FIG. 14illustrates a valve1494coupled to a skirt1492. Valve1494includes a membrane or segment of material1489which is coupled to an inside surface of skirt1492and extends over a hole or opening1487formed through the skirt. Membrane1489may be generally rectangular and formed from an elastic material or a fabric material such as Goretex or Musto. Membrane1489is coupled to skirt1492via a plurality of stitches1485, which couple only the corners of the membrane to the skirt while unstitched segments1483A,1483B,1483C,1483D of membrane1489between the stitches are not coupled to skirt1492. Under no pressure or in a default state, valve1494is in a closed or sealed configuration in which membrane1489lies flat and sealingly against opening1478. In operation, in situ, blood pressure deforms valve1494into an open configuration. More particularly, blood flows through opening1487and the pressure of the blood deforms or deflects membrane1489to create channels via unstitched segments1483A,1483B,1483C,1483D of membrane1489. In the open configuration, blood is permitted to flow into each pocket or compartment formed by skirt1492through channels which are created at the unstitched segments between the inner surface of skirt1492and the outer surface of membrane1489. Once the pressure drops, membrane1489returns to the closed configuration in which membrane1489lies flat against and covers opening1478, thereby trapping blood within each pocket to form a seal around the outer perimeter of the prosthesis.

In another embodiment shown inFIGS. 15,16,16A, and16B, the one-way port or valve is a flap valve which allows flow in one direction therethrough. More particularly,FIG. 15illustrates a valve1594coupled to a skirt1592whileFIG. 16illustrates valve1594removed from the prosthesis for illustration purposes only. Valve1594includes is a membrane or segment of material1581that has a paddle configuration with a stem or handle portion1579coupled to an inside surface of skirt1592via a plurality of stitches1585and a flap portion1577, which is not coupled to skirt1592. Membrane1581may be formed from a polymer material. Under no pressure or in a default state, valve1594is in a closed or sealed configuration in which flap portion1577of membrane1581extends over or covers opening1587formed through skirt1592. As shown inFIG. 16A, flap portion1577may be generally straight such that it lies flat and extends over opening1587in the closed configuration. In another configuration shown inFIG. 16B, flap portion1577may be curved such that it protrudes into and/or through opening1587in the closed configuration. In operation, in situ, blood pressure deforms valve1594into an open configuration. More particularly, blood flows through opening1587and the pressure of the blood deforms or deflects flap portion1577away from skirt1592, thereby forming a channel or passageway through which blood is permitted to flow into each pocket or compartment formed by skirt1592. Once the pressure drops, polymer membrane1581springs back or returns to the closed configuration in which membrane1581covers and seals opening1578, thereby trapping blood within each pocket to form a seal around the outer perimeter of the prosthesis.

In the embodiment ofFIG. 13, anti-paravalvular leakage component1390is coupled to outer surface103of heart valve prosthesis100along constriction region117thereof, described with respect toFIG. 1above. When deployed, anti-paravalvular leakage component1390may be positioned in situ at the native valve annulus, slightly above the valve annulus, slightly below the valve annulus, or some combination thereof. Since the annular anti-paravalvular leakage component is coupled to outer surface103of heart valve prosthesis100, longitudinal placement and/or the size and shape thereof is flexible and may be adjusted or adapted according to each application and to a patient's unique needs. For example, depending on the anatomy of the particular patient, the anti-paravalvular leakage component may be positioned on heart valve prosthesis100so that in situ the anti-paravalvular leakage component is positioned between heart valve prosthesis100and the interior surfaces of the native valve leaflets, between heart valve prosthesis100and the interior surfaces of the native valve annulus, and/or between heart valve prosthesis100and the interior surfaces of the left ventricular outflow track (LVOT).

Although embodiments depicted herein illustrate one or more anti-paravalvular leakage components integrated onto a heart valve prosthesis configured for implantation within an aortic valve, it would be obvious to one of ordinary skill in the art that the anti-paravalvular leakage components as described herein may be integrated onto a heart valve prosthesis configured for implantation implanted within other heart valves, such as a mitral valve or a pulmonary valve.