Patent Description:
The heart has four native valves, including the aortic valve, the pulmonary valve, the mitral valve (also known as the left atrioventricular valve), and the tricuspid valve (also known as the right atrioventricular valve). When these valves begin to fail, for example by not fully coapting and allowing retrograde blood flow (or regurgitation) across the valve, it may be desirable to repair or replace the valve. Prosthetic replacement heart valves may be surgically implanted via an open chest, open-heart procedure while the patient is on cardiopulmonary bypass. However, such procedures are extremely invasive, and frail patients, who may be the most likely to need a prosthetic heart valve, may not be likely to survive such a procedure. Prosthetic heart valves have been trending toward less invasive procedures, including collapsible and expandable heart valves that can be delivered through the vasculature in a transcatheter procedure.

The aortic and pulmonary valves typically have a relatively circular shape and a relatively small diameter compared to the left and right atrioventricular valves. As a result, transcatheter prosthetic heart valves designed for the mitral and tricuspid valve may have more significant challenges that need to be overcome compared to transcatheter prosthetic heart valve designs for the aortic and pulmonary valves.

<CIT> describes an assembly for the tricuspid orifice of a human heart, comprises an external frame connected to an internal stent carrying a tricuspid valve bioprosthesis and a sealing skirt. The external frame is configured to hold its position in the native tricuspid annulus. The internal stent is connected to the external frame by one or more fixing strands. The sealing skirt covers the interstitial space existing between the external frame and the internal stent. Developments are described which comprise in particular the use of a deformable region of the frame, various alternative embodiments of the sealing skirt, the use of a frame composed of multiple sub-sections, the use of fixing strands between the stent and the frame and of fixing elements for fixing the assembly to the native tissue, the use of sensors and/or actuators, and also the use of a stent in the inferior vena cava.

One or more of the above-mentioned problems and challenges are addressed by the subject-matter of claim <NUM>. Further embodiment in accordance with the invention are described in the dependent claims.

According to one aspect of the disclosure, a prosthetic heart valve includes a collapsible and expandable frame that, in an expanded condition, includes a central portion, an atrial portion flaring radially outwardly from the central portion, and a ventricular portion flaring radially outwardly from the central portion. A tube is positioned within the frame, the tube having a lumen extending along a longitudinal axis from the atrial portion toward the ventricular portion of the frame, wherein the tube is formed of tissue or fabric. A plurality of prosthetic leaflets are directly coupled to the tube to form a valve, the valve allowing blood to flow through the lumen of the tube in an antegrade direction but substantially blocking blood from flowing through the lumen of the tube in a retrograde direction. A plurality of cords each have a first end coupled to the frame and a second end coupled to the tube. Each of the plurality of cords extends in a radial direction toward the longitudinal axis. The tube excludes any metal structure directly attached to the tube. Each of the plurality of cords may be a suture. A skirt may be coupled to the frame, the skirt including an atrial portion extending radially inwardly from the frame and being connected to a first end of the tube, and a ventricular portion extending radially inwardly from the frame and being connected to a second end of the tube.

According to another aspect of the disclosure, a prosthetic heart valve includes a collapsible and expandable frame that, in an expanded condition, includes a central portion, an atrial portion flaring radially outwardly from the central portion, and a ventricular portion flaring radially outwardly from the central portion. A tube may be positioned within the frame, the tube having a lumen extending along a longitudinal axis from an inflow end to an outflow end, wherein the tube is formed of tissue or fabric. A plurality of first cords may each have a first end coupled to the frame and a second end coupled to the inflow end of the tube, the first plurality of cords maintaining the inflow end of the tube in an open condition. A pair of second cords may each have a first end coupled to the frame and a second end coupled to the outflow end of the tube, the pair of second cords coupled to diametrically opposed portions of the outflow end of the tube so that two free edges of the outflow end of the tube are capable of collapsing toward each other and opening away from each other. The plurality of first cords may be sutures, and the pair of second cords may be sutures. The tube may be formed of tissue that is rolled into a generally cylindrical shape. The tube may be formed as two pieces of fabric that are coupled together, via a pair of seams, to form a generally cylindrical shape, the pair of seams aligning with the pair of second cords. The prosthetic heart valve may exclude prosthetic leaflets separate from the tube.

According to a further aspect of the disclosure, a method of replacing an atrioventricular heart valve of a heart may include expanding a frame into the heart valve, the frame including a central portion in contact with an annulus of the heart valve, an atrial portion flaring radially outwardly from the central portion, and a ventricular portion flaring radially outwardly from the central portion. A tube may be suspended within the frame, the tube being suspended by a plurality of cords each having a first end coupled to the frame and a second end coupled to the tube, the tube having a lumen extending along a longitudinal axis from an inflow end to an outflow end, the tube being formed of tissue or fabric, each of the plurality of sutures extending in a radial direction toward the longitudinal axis. After expanding the frame into the heart valve, blood may flow in an antegrade direction from an atrium to a ventricle through the tube during atrial systole, but blood may be prevented from flowing in a retrograde direction from the ventricle to the atrium through the tube during ventricular systole. The tube may move toward the atrium and then toward the ventricle while the heart cycles between atrial systole and ventricular systole, but the frame may remain stationary as the heart cycles between atrial systole and ventricular systole. A plurality of prosthetic leaflets may be directly coupled to the tube to form a valve. The plurality of cords may include a plurality of first cords each having a first end coupled to the frame and a second end coupled to the inflow end of the tube, the first plurality of cords maintaining the inflow end of the tube in an open condition. The plurality of cords may include a pair of second cords each having a first end coupled to the frame and a second end coupled to the outflow end of the tube, the pair of second cords coupled to diametrically opposed portions of the outflow end of the tube so that two free edges of the outflow end of the tube are capable of collapsing toward each other and opening away from each other. The tube may be formed of tissue that is rolled into a generally cylindrical shape. The tube may be formed as two pieces of fabric that are coupled together, via a pair of seams, to form a generally cylindrical shape, the pair of seams aligning with the pair of second cords.

According to still another aspect of the disclosure, a method of replacing a right atrioventricular valve of a heart of a patient may include delivering an anchor to a superior vena cava of the patient. The anchor may be expanded into the superior vena cava. After expanding the anchor, a prosthetic heart valve may be delivered to the right atrioventricular valve. The prosthetic heart valve may be expanded within the right atrioventricular valve while a tether is coupled to the prosthetic heart valve. The tether may be tensioned and fixed to the anchor while the tether is tensioned. Fixing the tether may be performed after expanding the anchor and after expanding the prosthetic heart valve. Expanding the prosthetic heart valve may include positioning a pair of projections in contact with tissue of the right atrioventricular valve on an outflow side of the right atrioventricular valve. After expanding the prosthetic heart valve within the right atrioventricular valve, the prosthetic heart valve may not be in contact with tissue of the right atrioventricular valve on an inflow side of the right atrioventricular valve. Tensioning the tether may be performed by pulling the tether proximally while the tether is looped over an arch of the anchor. Tensioning the tether may be performed by pulling the tether proximally while the tether is extending through a tether connection mechanism of the anchor, and fixing the tether may be performed by releasing force on the tether whereby a tine or barb of the anchor penetrates the tether to maintain the tether in a tensioned state.

As used herein, the term "inflow end," when used in connection with a prosthetic heart valve, refers to an end of the prosthetic heart valve into which blood first flows when the prosthetic heart valve is implanted in an intended position and orientation. On the other hand, the term "outflow end," when used in connection with a prosthetic heart valve, refers to the end of the prosthetic heart valve through which blood exits when the prosthetic heart valve is implanted in an intended position and orientation. In the figures, like numbers refer to like or identical parts. As used herein, the terms "substantially," "generally," "approximately," and "about" are intended to mean that slight deviations from absolute are included within the scope of the term so modified. When ranges of values are described herein, those ranges are intended to include sub-ranges. For example, a recited range of <NUM> to <NUM> includes <NUM>, <NUM>, <NUM>, and other single values, as well as all sub-ranges within the range, such as <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>, and others.

The present disclosure is generally directed to collapsible prosthetic tricuspid valves. Unless stated otherwise, the term "tricuspid valve" as used herein refers to the right atrioventricular valve, as opposed to being a generic term for a three-leaflet valve. Despite the above, it should be understood that the features described herein may apply to other types of prosthetic heart valves, including prosthetic heart valves that are adapted for use in other heart valves, such as the mitral heart valve. Further, the features of the prosthetic heart valves described herein may, in some circumstances, be suitable for surgical (e.g., non-collapsible) prosthetic heart valves. However, as noted above, the disclosure is provided herein in the context of a collapsible and expandable prosthetic tricuspid valve.

<FIG> is a schematic illustration of the right atrioventricular valve (commonly referred to as the tricuspid valve). The tricuspid valve separates the right atrium from the right ventricle, and typically includes three leaflets, which include a posterior leaflet, an anterior leaflet, and a septal leaflet. The septal leaflet is positioned nearest the interventricular septum ("IVS"). The tricuspid valve annulus may include conduction nodes near the connection point between the annulus and the septal leaflet, including for example the atrioventricular node ("AV node"). The AV node may typically be positioned on the atrial side of the native tricuspid valve annulus. Electrical impulses may be conducted from the AV node, via the bundle of His, to the Purkinje fibers that provide electrical conduction to the ventricles. Papillary muscles along the right ventricular wall ("RVW") may support chordae tendineae coupled to the tricuspid valve leaflets to prevent inversion of the leaflets during normal physiological operation. The left atrioventricular valve (commonly referred to as the mitral valve) may have a generally similar structure as the tricuspid valve, although many differences do exist - including for example the mitral valve typically includes two leaflets (an anterior and posterior leaflet) and has the general shape of a hyperbolic paraboloid or "saddle"-type shape. Both the mitral valve annulus and tricuspid valve annulus may be very large compared to the aortic and pulmonary valves. The tricuspid valve can range from between about <NUM> to about <NUM> in perimeter-derived diameter. However, it should be understood that these sizes are merely exemplary.

Because of the large sizes of the mitral valve and the tricuspid valve, it may be desirable for a collapsible prosthetic mitral or tricuspid valve to have a dual-frame design. In other words, a first large outer frame may be used primarily to anchor and/or seal the prosthetic heart valve at the native annulus, with a second smaller inner frame connected to and positioned within the outer frame. The inner frame may function primarily to support one or more prosthetic valve leaflets. In some instances, the inner frame may be generally cylindrical when implanted, with the inner and outer frames connected in a way such that forces from the native valve that deform the outer frame tend not to deform the inner frame (or at least not to a significant enough extent to reduce the ability of the prosthetic leaflets within the inner frame to properly coapt). Having a single large frame that serves both the anchoring/sealing function as well as directly supporting prosthetic leaflets may be undesirable in the tricuspid and mitral valves because the leaflets may need to be very large and may be more likely to be deformed during regular operation due to forces from the native annulus. Some embodiments described below provide the ability to have a single supporting frame for anchoring while avoiding at least some of the concerns described above for a single-frame mitral or tricuspid valve prosthesis. And while these embodiments may be suitable for either mitral or tricuspid valve replacement, they may be particularly suited for tricuspid valve replacement because of the lower forces and pressures that occur within and across the tricuspid valve compared to the mitral valve.

<FIG> shows a perspective view of a collapsible and expandable prosthetic heart valve <NUM>. Although prosthetic heart valve <NUM> may be suitable as a replacement for a native mitral or tricuspid valve, prosthetic heart valve <NUM> is generally described below in the context of a prosthetic tricuspid valve. A main structural component of the prosthetic heart valve <NUM> is a frame <NUM>. Portions of the frame <NUM> are covered by a liner or skirt material in <FIG>.

Before returning to describe other portions of the prosthetic heart valve <NUM>, an exemplary frame <NUM> is described. However, it should be understood that frame <NUM> is merely exemplary, and other frames having generally similar overall designs may be used in place of the frame <NUM> without a significant deviation from the functionality of the prosthetic heart valve <NUM>.

One exemplary option for the design of the frame <NUM> is shown in <FIG> shows the frame <NUM> from a side view while in the expanded condition, with the inflow end of the frame <NUM> being positioned toward the top of <FIG> and the outflow end of the frame <NUM> being positioned toward the bottom of <FIG>. Frame <NUM> may be formed of a superelastic and/or shape memory material such as Nitinol. According to some examples, other biocompatible metals or metal alloys may be suitable. For example, superelastic and/or self-expanding metals other than Nitinol may be suitable, while still other metals or metal alloys such as cobalt-chromium or stainless steel may be suitable, particularly if the stent or support structure is intended to be balloon expandable. In some examples, the frame <NUM> may be laser cut from a single tube, such as a shape memory metal tube. The shape memory metal tube may be Nitinol or any other bio-compatible metal tube. In some embodiments, the frame <NUM> may be formed of a shape memory polymer.

The frame <NUM> may be adapted to expand from a collapsed or constrained configuration to an expanded configuration. According to some examples, the frame <NUM> may be adapted to self-expand, although the frame could instead be partially or fully expandable by other mechanisms, such as balloon expansion. The frame <NUM> may be maintained in the collapsed configuration during delivery, for example via one or more overlying sheaths that restrict the frame from expanding. The frame <NUM> may be expanded during deployment from the delivery device once the delivery device is positioned within or adjacent to the native valve annulus. In the expanded configuration, an atrial portion <NUM> and ventricular portion <NUM> may extend radially outward from a central longitudinal axis of the frame <NUM> and/or a central portion <NUM> of the frame <NUM> and may be considered to flare outward relative to the central longitudinal axis of the frame <NUM> and/or central portion <NUM>. The atrial portion <NUM> and ventricular portion <NUM> may be considered flanged relative to central portion <NUM>. In some embodiments, the flared configuration of the atrial and ventricular portions <NUM>, <NUM> and the central portion <NUM> may define a general hourglass shape in a side view of the frame <NUM>. That is, the atrial and ventricular portions <NUM>, <NUM> may be flared outwards relative to the central portion <NUM> and then curve or bend to point at least partially back in the axial direction. It should be understood, however, that an hourglass configuration is not limited to a symmetrical configuration. Atrial portion <NUM> may be referred to herein as an atrial portion, an atrial cuff, or an atrial anchor. Similarly, ventricular portion <NUM> may be referred to herein as a ventricular portion, a ventricular cuff, or a ventricular anchor. It should be understood that, in this context, the terms "portion," "cuff," and "anchor" are intended to be used interchangeably with each other.

As noted above, the frame <NUM> may include an atrial portion or anchor <NUM>, a ventricular portion or anchor <NUM>, and a central portion <NUM> coupling the atrial portion to the ventricular portion. The atrial portion and ventricular portion may be referred to herein as atrial or ventricular disks. Atrial portion <NUM> may be configured and adapted to be disposed on an atrial side of a native valve annulus and may flare radially outwardly from the central portion <NUM>. Ventricular portion <NUM> may be configured and adapted to be disposed on a ventricular side of the native valve annulus and may also flare radially outwardly from the central portion <NUM>. The central portion <NUM> may be configured to be situated in the valve orifice, for example in contact with the native valve annulus. In use, the atrial portion <NUM> and ventricular portion <NUM> effectively clamp the native valve annulus on the atrial and ventricular sides thereof, respectively, anchoring the prosthetic heart valve <NUM> in place.

The atrial portion <NUM> may be formed as a portion of a stent or other support structure that includes or is formed by a plurality of generally diamond-shaped cells, although other suitable cell shapes, such as triangular, quadrilateral, or polygonal may be appropriate. In some examples, the atrial portion <NUM> may be formed as a braided mesh, as a portion of a unitary stent, or a combination thereof. According to one example, the stent that includes the atrial portion <NUM> may be laser cut from a tube of Nitinol and heat set to the desired shape so that the stent, including atrial portion <NUM>, is collapsible for delivery, and re-expandable to the set shape during deployment. The atrial portion <NUM> may be heat set into a suitable shape to conform to the native anatomy of the valve annulus to help provide a seal and/or anchoring between the atrial portion <NUM> and the native valve annulus. The shape-set atrial portion <NUM> may be partially or entirely covered by a cuff or skirt, on the luminal and/or abluminal surface of the atrial portion <NUM>. The skirt may be formed of any suitable material, including biomaterials such as bovine pericardium, biocompatible polymers such as ultra-high molecular weight polyethylene ("UHMWPE"), woven polyethylene terephthalate ("PET") or expanded polytetrafluoroethylene ("ePTFE"), or combinations thereof. The atrial portion <NUM> may include features for connecting the atrial portion to a delivery system. For example, the atrial portion <NUM> may include pins or tabs <NUM> around which sutures (or suture loops) of the delivery system may wrap so that while the suture loops are wrapped around the pins or tabs <NUM>, the frame <NUM> maintains a connection to the delivery device. However, it should be understood that pins or tabs <NUM> may be completely optional.

The ventricular portion <NUM> may also be formed as a portion of a stent or other support structure that includes or is formed of a plurality of diamond-shaped cells, although other suitable cell shapes, such as triangular, quadrilateral, or polygonal may be appropriate. In some examples, the ventricular portion <NUM> may be formed as a braided mesh, as a portion of a unitary stent, or a combination thereof. According to one example, the stent that includes the ventricular portion <NUM> may be laser cut from a tube of Nitinol and set to the desired shape (e.g., via heat treating) so that the ventricular portion <NUM> is collapsible for delivery, and re-expandable to the set shape during deployment. The ventricular portion <NUM> may be partially or entirely covered by a cuff or skirt, on the luminal and/or abluminal surface of the ventricular portion <NUM>. The skirt may be formed of any suitable material described above in connection with the skirt of atrial portion <NUM>. It should be understood that the atrial portion <NUM> and ventricular portion <NUM> may be formed as portions of a single support structure, such as a single stent or braided mesh. However, in other embodiments, the atrial portion <NUM> and ventricular portion <NUM> may be formed separately and coupled with one another.

The frame <NUM> may be configured to expand circumferentially (and radially) and foreshorten axially as the prosthetic heart valve <NUM> expands from the collapsed delivery configuration to the expanded deployed configuration. The frame <NUM> may define a plurality of atrial cells 211a, 211b in two circumferential rows. For example, the first row of atrial cells 211a may be generally diamond shaped and positioned on the inflow end of the frame <NUM>. The second row of atrial cells 211b may be positioned at least partially between adjacent atrial cells 211a in the first row, with the atrial cells 211b in the second row being positioned farther from the inflow end than the first row of atrial cells 211a. The frame <NUM> may include twelve atrial cells 211a in the first row each having a diamond shape, and twelve atrial cells 211b in the second row each having a skewed diamond shape. This skewed diamond shape, which is wider nearer the inflow (or top) end and narrower nearer the outflow (or bottom) end, may assist in transitioning from twelve cells per row on the atrial side of the stent to twenty-four cells per row on the ventricular side. However, it should be understood that the particular number, shape, and configuration of atrial cells may be different than the specific embodiment shown.

The frame <NUM> may include a plurality of ventricular cells 211c in a first row, and another plurality of ventricular cells 211d in a second row. The first row of ventricular cells 211c may be at the outflow end of the frame <NUM>, and the second row of ventricular cells 211d may be positioned farther from the outflow end than, and adjacent to, the first row of ventricular cells 211c. In the illustrated embodiment the first and second rows of ventricular cells 211c, 211d are all generally diamond-shaped and have substantially the same or identical size, with twenty-four cells in the first row of ventricular cells 211c and twenty-four cells in the second row of ventricular cells 211d. However, it should be understood that the particular number, shape, and configuration of ventricular cells may be different than the specific embodiment shown.

Frame <NUM> is also illustrated as including three rows of center cells. A first row of center cells 211e may be positioned adjacent to the atrial end of the frame <NUM>, each cell 211e being positioned between a pair of adjacent atrial cells 211b. Each center cell 211e may be substantially diamond-shaped, but it should be understood that adjacent center cells 211e do not directly touch one another. The first row of center cells 211e may include twelve center cells 211e, with the combination of atrial cells 211b and the center cells 211e helping transition from rows of twelve cells on the atrial side to rows of twenty-four cells on the ventricular side. A second row of center cells 211f may be positioned at a longitudinal center of the frame <NUM>, each center cell 211f being positioned between an atrial cell 211b and center cell 211e. In the illustrated embodiment, center cells 211f in the second row may be diamond-shaped, with the second row including twenty-four center cells 211f. Finally, a third row of center cells <NUM> may be positioned between the second row of center cells 211f and the second row of ventricular cells 211d. The third row of center cells <NUM> may include twenty-four cells and they may each be substantially diamond-shaped. However, it should be understood that the particular number, shape, and configuration of center cells may be different than the specific embodiment shown.

All of the cells 211a-g may be configured to expand circumferentially and foreshorten axially upon expansion of the frame <NUM>. A pin or tab <NUM> may extend from an apex of each atrial cell 211a in the first row in a direction toward the outflow end of the frame <NUM>. Although one pin or tab <NUM> is illustrated in each atrial cell 211a in the first row, in other embodiments fewer than all of the atrial cells in the first row may include a pin or tab. These pins or tabs <NUM> may be configured to receive a suture or suture loop of a delivery device so that the frame <NUM> (and thus the prosthetic heart valve <NUM>) remains coupled to the delivery system until the user decouples the suture loops from the pins or tabs <NUM>.

In some embodiments, frame <NUM> may include a plurality of tines or barbs <NUM> extending from a center portion or ventricular portion of the frame for piercing or otherwise engaging native tissue in the native annulus or in the native leaflets. In the illustrated embodiment, each barb <NUM> is connected to a ventricular cell 211d in the second row. In some embodiments, the barb <NUM> may be coupled to an inflow or outflow apex of each cell. In the particular illustrated embodiment, the barbs <NUM> are coupled to ventricular cells 211d on an inflow half of the cell, on either side of the inflow apex. For example, the barb <NUM> in one ventricular cell 211d may be coupled to the inflow half of that cell on a right side of the apex, with the adjacent ventricular cell 211d having a barb coupled to the inflow half of that cell on a left side of the apex. With this configuration, the barbs <NUM> are provided in pairs with relatively little space between the barbs of a pair, but a relatively large space between adjacent pairs. However, it should be understood that the barbs <NUM> may in other embodiments be centered with even spacing between adjacent barbs. In the collapsed condition of the frame <NUM>, each barb <NUM> extends toward the outflow end of the frame, each barb being positioned within a ventricular cell 211d in the second row. In the expanded condition of the frame <NUM>, the barbs <NUM> may hook upwardly back toward the inflow end, the barbs being configured to pierce native tissue of the valve annulus, such as the native leaflets, to help keep the prosthetic heart valve from migrating under pressure during beating of the heart. However, in some embodiments, the tines or barbs <NUM> may be completely omitted. For example, the tines or barbs <NUM> may be particularly helpful when used in a native mitral valve, as a prosthetic mitral valve must withstand relatively high pressures, and the tines or barbs <NUM> may assist with anchoring. However, the tines or barbs <NUM> may be omitted when the prosthetic heart valve is used as a prosthetic tricuspid valve, as pressures within the right heart are significantly lower than pressures within the left heart, and thus the tines or barbs <NUM> may not be needed at all for anchoring. In fact, the tines or barbs <NUM> may increase the likelihood of conduction disturbances, and particularly in the context of a prosthetic tricuspid valve, it may be preferable to omit the tines or barbs <NUM> entirely.

In addition to the frame <NUM>, a typical prosthetic atrioventricular valve may include an inner metal frame to which prosthetic leaflets are attached. However, referring back to <FIG>, prosthetic heart valve <NUM> may completely omit any inner metallic or otherwise rigid frame to which the prosthetic leaflets are attached. For example, in the particular embodiment shown in <FIG>, prosthetic heart valve <NUM> omits an inner metallic or otherwise rigid frame, and instead includes a soft tube <NUM> that is secured to the frame <NUM>. The tube <NUM> is formed of any suitable biocompatible material, excluding metallic materials, but including for example PET, PTFE, ePTFE, UHMWPE, etc., including in a fabric form or another form, including extruded or flat sheet polymers. In some examples not forming part of the invention, the tube <NUM> may be formed of tissue, such as bovine or porcine pericardium. Preferably, the material (e.g., fabric or tissue) that forms tube <NUM> is substantially fluid-tight or otherwise substantially impermeable to blood so that blood is only able to flow through the lumen of the tube <NUM>, and not through the wall(s) that form the tube <NUM>. A plurality of prosthetic leaflets <NUM> may be coupled directly to the tube <NUM>, for example by suturing. In the illustrated embodiment of <FIG>, the prosthetic heart valve <NUM> includes three leaflets <NUM>, with each leaflet including a free edge <NUM> and an attached edge <NUM>. In operation, the free edges <NUM> move away from each other to allow for blood to flow through the tube <NUM> and the leaflets <NUM> in the antegrade direction (i.e., from the atrium to the ventricle), and coapt together to restrict blood from flowing through the tube <NUM> in the retrograde direction (i.e., from the ventricle to the atrium). The attached edge <NUM> may be opposite the free edge <NUM> and may be attached to the tube <NUM> via any suitable mechanism, including fasteners such as sutures. In the illustrated embodiment, the attached edges <NUM> generally follow a "U"-shaped, catenary, or generally parabolic pattern. Preferably, the prosthetic leaflets <NUM> are formed of bioprosthetic tissue, such as bovine or porcine pericardium, but in other embodiments, the prosthetic leaflets <NUM> may be formed of fabrics or other synthetic materials, such as PET, PTFE, UHMWPE, etc..

Still referring to <FIG>, the prosthetic heart valve <NUM> may include a covering or lining, such as a skirt <NUM>. Skirt <NUM> may be formed of any suitable material, including tissue, fabric, or extruded or flat sheet polymers. For example, skirt <NUM> may be formed of a woven synthetic fabric such as PET, PTFE, UHMWPE, etc. that functions to contact native tissue at or adjacent to the native heart valve annulus and provide a conforming seal. For example, skirt <NUM> may include an outer or peripheral section <NUM> attached to the luminal or abluminal (as shown in <FIG>) surface of the frame <NUM>, for example via suturing. Upon implantation of the prosthetic heart valve <NUM>, the outer section <NUM> of the skirt <NUM> preferably contacts the native valve annulus to help seal against the native valve annulus and to prevent paravalvular leakage around the prosthetic heart valve <NUM>. The skirt <NUM> may also include an outflow section <NUM> generally extending radially inwardly from the frame <NUM> to the tube <NUM>. The outflow section <NUM> may be formed of the same or different materials as the peripheral or outer section <NUM> of the skirt <NUM>, and for example, may be substantially impermeable to blood flowing therethrough. The outflow section <NUM> in the embodiment shown in <FIG> is substantially planar and has an annular shape, with the outer circumference or perimeter of the outflow section <NUM> coupled to the frame <NUM> (e.g., via sutures) and the inner circumference or perimeter of the outflow section <NUM> coupled to the outflow end of the tube <NUM> (e.g., via sutures). The skirt <NUM> may also include an inflow section that is substantially similar to the outflow section, with the exception that it is positioned on the inflow section of the prosthetic heart valve <NUM> (which is not visible in the view of <FIG>). Thus, the inflow section may be generally annular with an outer perimeter or circumference attached to the frame <NUM> and an inner perimeter of circumference attached to the outer perimeter of the inflow end of tube <NUM>.

<FIG> shows the prosthetic heart valve <NUM> of <FIG> prior to the prosthetic leaflets <NUM> being attached to the tube <NUM>. <FIG> shows particularly well one mechanism by which the tube <NUM> may be coupled to the prosthetic heart valve <NUM>. For example, although the inflow and outflow ends of the tube <NUM> may be coupled to the inner perimeters of the inflow and outflow sections of skirt <NUM>, those couplings may be primarily to help ensure that blood only flows through the lumen of tube <NUM>. It may be desirable to provide additional structural support for the tube <NUM>, particularly since the prosthetic leaflets <NUM> therein will need to resist significant forces when they close during ventricular systole. As shown in <FIG>, one or more connectors <NUM> may directly couple the tube <NUM> to the frame <NUM>. For example, the embodiment of <FIG> illustrates a plurality of radially extending sutures <NUM>, each suture <NUM> having a first end coupled to the frame <NUM> and a second end coupled to the tube <NUM>, with the suture <NUM> generally extending along a line that would pass through (or nearly pass through) a radial center of the tube <NUM>. In the illustrated embodiment, one group of sutures <NUM> is provided at the outflow end of the prosthetic heart valve <NUM>, and although not shown, a generally similar or identical group of suture connectors <NUM> is provided at the inflow end of the prosthetic heart valve <NUM>, so that both the inflow and outflow ends of the tube <NUM> are secured to the frame <NUM> via radially extending sutures <NUM>. The suture connectors <NUM> may only provide support in tension, and thus help to minimize the movement of the inner valve (e.g., the tube <NUM> with the prosthetic leaflets <NUM> coupled thereto) during normal operation of the prosthetic heart valve <NUM>. On the other hand, when the frame <NUM> is compressed (e.g., when being collapsed for delivery, or when the native tissue applies force to the frame <NUM> during the normal cycle of the heart), that compressive force is not translated via the suture connectors <NUM> to the tube <NUM>. In some embodiments, a tensioning mechanism may be provided with one or more of the suture connectors <NUM> to allow for adjusting the tension of the suture connectors <NUM> during or after delivery and deployment of the prosthetic heart valve <NUM>. One example of a suitable tensioning mechanism is a ratcheting mechanism, with a portion of the suture connectors having a feature that slides against the connection point in only one direction to tighten. Alternatively, a mechanism that knots, swages, or pins at the connection point may be used when the desired tension and/or annular motion is reached. It should be understood that, although the term "suture connector" is used herein, the connectors are not actually limited to sutures - but may be any suitable cord, string, or wire-like material that is sufficiently strong to provide the desired support to the inner valve. Further, it should be understood that suture connectors <NUM> may be only one example of how the tube <NUM> may be coupled to the frame <NUM>. For example, instead of using suture connectors <NUM>, rigid arms, such as arms formed of nickel-titanium alloy or Nitinol, may be incorporated into the frame <NUM> with the arms being bent inwardly to form a general "C" shape with the ends of the "C" shape coupled to the top and bottom, respectively, of the tube <NUM>. Examples of suitable arm connectors are described in greater detail in <CIT>. Such connector arms may provide more rigid support than the suture connectors <NUM>.

As noted above, prosthetic heart valve <NUM> of the present invention lacks a metallic inner frame for supporting the prosthetic leaflets <NUM> that is frequently found in collapsible and expandable prosthetic atrioventricular valves. By eliminating this metallic inner frame, the prosthetic heart valve <NUM> of the present invention is able to collapse to a smaller size (e.g., a smaller French size) and thus a smaller catheter may be used to deliver the prosthetic heart valve <NUM>, compared to an otherwise similar prosthetic heart valve that includes a metallic or otherwise rigid inner frame. It is generally desirable to use smaller catheters, when possible, to deliver a prosthetic heart valve via a transvascular route since larger catheters may present a greater risk to the patient, particularly at the access site (e.g., the femoral vein). This design may also reduce the forces required to load the prosthetic heart valve into the delivery device. In other words, when collapsing the prosthetic heart valve <NUM> to the collapsed condition for storage within a delivery device for the procedure, a smaller force may be required to collapse the valve which is generally desirable. Still, other benefits may arise from the single-frame design of prosthetic heart valve <NUM>. For example, retrieving a prosthetic heart valve after it has been partially or completely deployed into the native valve annulus can be very difficult when two separate rigid frames are used. The use of two separate rigid frames may increase the forces required to retrieve (e.g., by re-collapsing) the prosthetic heart valve, and the existence of two spaced apart rigid frame structures may create a greater likelihood of frame structure getting "caught" on a retrieval catheter as the prosthetic heart valve is being re-collapsed into the retrieval catheter. Forming the prosthetic heart valve <NUM> with only a single rigid frame may reduce or eliminate both of these potential issues. Still another potential benefit of the single frame design of prosthetic heart valve <NUM> is that, because there is no rigid connection between the prosthetic leaflets <NUM> and the frame <NUM> that is directly in contact with the native valve, any deformation of the frame <NUM> during normal operation of the prosthetic heart valve <NUM> is highly unlikely to result in any deformation of the prosthetic leaflets <NUM>. Deformation of the prosthetic leaflets <NUM> is undesirable because any deformation to the shape of the prosthetic leaflets <NUM> during operation may negatively affect the ability of the prosthetic leaflets <NUM> to properly coapt and to create a complete seal during ventricular systole. In other words, if the deformation of the frame <NUM> caused deformation of the prosthetic leaflets <NUM>, the prosthetic heart valve <NUM> may allow for undesirable regurgitation across the prosthetic leaflets <NUM>.

Although prosthetic heart valve <NUM> is described above as having prosthetic leaflets <NUM> directly attached (e.g., via sutures) to the tube <NUM>, in some embodiments, additional support materials may be provided at the leaflet-tube interface. For example, an underwire type of structure may be attached to the tube <NUM>, and portions of the prosthetic leaflets <NUM> attached to the underwire, to provide additional support. The underwire may take the form of wire, such as a strand of Nitinol, that has a general "U"-shape corresponding to each prosthetic leaflet <NUM>. For example, referring back to <FIG>, a Nitinol underwire that follows the general contours of the attachment edge <NUM> may be interposed between the prosthetic leaflets <NUM> and the tube <NUM>. In some embodiments, the underwire may be substantially continuous so that the prosthetic leaflets <NUM> are attached to the underwire along the leaflet bellies (e.g., along attachment edge <NUM>), as well as the commissures where adjacent prosthetic leaflets <NUM> join. In some embodiments, only the leaflet bellies may be attached to an underwire provided on the tube <NUM>. In some embodiments, only the leaflet commissures may be attached to an underwire (or another support structure, such as a commissure plate) on the tube <NUM>. It should be understood that these additional support structures may offer a compromise in the sense that, while the additional metal (or otherwise rigid) material on the tube <NUM> may increase bulk, it may only increase bulk slightly compared to the use of a full inner metal stent, but the additional support to the prosthetic leaflets <NUM> may justify the additional bulk created.

Although prosthetic heart valve <NUM> is described and shown in connection with <FIG> as including prosthetic leaflets <NUM> attached to the tube <NUM>, in some embodiments, the tube itself may function as a valve without the need for separate leaflets. For example, <FIG> illustrates a prosthetic heart valve <NUM>' that is similar to prosthetic heart valve <NUM> in a number of respects. For example, prosthetic heart valve <NUM>' may include frame <NUM>, which may be similar or identical to frame <NUM> described above. However, as with prosthetic heart valve <NUM>, the frame <NUM> of prosthetic heart valve <NUM>' may take other suitable forms besides the particular features described in connection with frame <NUM>. In addition, prosthetic heart valve <NUM>' may include a tube <NUM>' of soft material, such as tissue or fabrics as described in connection with tube <NUM>'. The main difference between prosthetic heart valve <NUM> and <NUM>' is that the tube <NUM>' itself provides the valving functionality, without the need for separate leaflets. In particular, the inflow end of tube <NUM>' (toward the bottom in the view of <FIG>) may be coupled to the frame <NUM> in substantially the same fashion as described in connection with prosthetic heart valve <NUM>. In particular, a plurality of connectors <NUM>, which may be suture or suture-like connectors <NUM>, extend radially outwardly from the inflow end of the tube <NUM>' to the frame <NUM> to provide connection points therebetween. Each suture connector <NUM> may have a first end coupled to the inflow end of the tube <NUM>' and a second end coupled to the frame <NUM>, with the suture connectors <NUM> generally extending in a direction toward the radial center of the tube <NUM>'. Preferably, enough suture connectors <NUM> are provided on the inflow end of the tube <NUM>' to ensure that the inflow end of the tube <NUM>' cannot close or otherwise collapse on itself. For example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more suture connectors <NUM> may connect the inflow end of the tube <NUM>' to the frame <NUM>. Preferably, the suture connectors <NUM> are positioned at substantially equal intervals around the circumference of the inflow end of the tube <NUM>'. The outflow end of the tube <NUM>', however, has fewer suture connectors <NUM>. In the illustrated embodiment, the outflow end of the tube <NUM>' has exactly two suture connectors <NUM> that connect the outflow end of the tube <NUM>' to the frame <NUM>, with the two suture connectors <NUM> being positioned at diametrically opposed points of the outflow end of the tube <NUM>'. With this configuration, the two suture connectors <NUM> at the outflow end of the tube <NUM>' will maintain the position of the connection points of the tube <NUM>' relative to the frame <NUM>. However, because the outflow end of the tube <NUM>' excludes additional suture connectors <NUM>, the unconnected or free edges of the outflow end of the tube <NUM>' are generally free to open and close depending on the pressure gradient across the prosthetic heart valve <NUM>'. For example, during atrial systole, the higher pressure in the atrium will force blood to flow through the tube <NUM>', with the inflow end of the tube <NUM>' being restricted from closing due to the various suture connectors <NUM>, and the outflow end of the tube <NUM>' naturally "wanting" to remain open because of the pressure gradient. However, during ventricular systole, the higher pressure in the ventricle will tend to cause the outflow end of the tube <NUM>' to collapse where the suture connectors <NUM> allow for such collapsing. In the illustrated embodiment of <FIG>, arrows <NUM> illustrate that the outflow end of the tube <NUM>' will tend to close on each other on either side of the pair of suture connectors <NUM>, much like a duckbill valve. In other words, if the suture connectors <NUM>' on the outflow end of the tube <NUM>' are thought of as being positioned at <NUM> o'clock and <NUM> o'clock, the outflow end of the tube <NUM>' will tend to close along the <NUM> o'clock and <NUM> o'clock directions when the pressure in the ventricle is greater than the pressure in the atrium.

Still referring to <FIG>, the tube <NUM>' may be formed as a single generally cylindrical piece of fabric or tissue (e.g., tissue that is rolled into a tube shape), or two separate pieces of fabric or tissue sewn together with opposing seams. If the tube <NUM>' is formed as two pieces of material sutured together at opposing seams (e.g., seams running vertically or longitudinally), it may be preferable for the suture connectors <NUM> at the outflow end of the tube <NUM>' to connect at or near the seams, so that the outflow end of the tube <NUM>' opens and closes between the seams.

Although not shown in detail in <FIG>, prosthetic heart valve <NUM>' may include a skirt substantially similar or identical to skirt <NUM>. For example, as shown in <FIG>, a skirt <NUM> may be generally at the outflow end of prosthetic heart valve <NUM>', but with a center portion of the skirt <NUM> angled or oriented toward the inflow end, with the tube <NUM>' extending through a center portion of the skirt <NUM>. In other embodiments, the skirt <NUM> at the outflow end could be omitted. In either case a skirt may be provided at the inflow end of the prosthetic heart valve <NUM>' as well. In other embodiments described herein, the outflow skirt (e.g. skirt <NUM>) is provided at the outflow most end of the leaflet assembly, or even downstream of the leaflets. However, because the outflow end of the tube <NUM>' acts as the valve, and includes edges that are in motion, the outflow skirt <NUM> cannot be directly attached to the outflow end of the tube <NUM>', as such connection could interfere with the opening and closing of the outflow end of the tube <NUM>'. Thus, the center portion of the skirt <NUM> is coupled to the tube <NUM>' at a spaced distance away from the outflow end of the tube <NUM>' to allow the outflow end of the tube <NUM>' to open and close during normal operation.

One possible result of excluding a rigid inner frame, or otherwise any rigid attachment between the prosthetic leaflets <NUM> and the frame <NUM>, is that pulsatile motion of the prosthetic leaflets <NUM> may occur during normal operation of prosthetic heart valve <NUM>. For example, <FIG> illustrate the prosthetic heart valve <NUM> deployed into a test system that simulates flow through the prosthetic heart valve <NUM>. In the view of <FIG>, the inflow side of the prosthetic heart valve <NUM> is toward the right of the views and the outflow side of the prosthetic heart valve is toward the left of the views. <FIG> illustrates a portion of the test in which the fluid pressure on the inflow (right) side of the prosthetic heart valve <NUM> is greater than on the outflow (left) side of the prosthetic heart valve <NUM>, forcing the prosthetic leaflets <NUM> to open to allow fluid to flow through the tube <NUM>. <FIG> illustrates a portion of the test in which the fluid pressure on the outflow (left) side of the prosthetic heart valve <NUM> is greater than on the inflow (right) side of the prosthetic heart valve <NUM>, forcing the prosthetic leaflets <NUM> to close to prevent fluid from flowing backward through the tube <NUM>. As can be seen by comparing <FIG>, when the leaflets <NUM> are open and fluid is flowing from the inflow (right) to the outflow (left) end of the prosthetic heart valve <NUM>, the prosthetic leaflets <NUM> and tube <NUM> are positioned relatively far in the outflow direction. On the other hand, when the leaflets <NUM> are closed and are preventing fluid from flowing from the outflow (left) to the inflow (right) end, the prosthetic leaflets <NUM> and tube <NUM> are positioned relatively far in the inflow direction. Despite the movement of the prosthetic leaflets <NUM> and the tube <NUM>, the frame <NUM> remains in the same (or substantially the same) position during the simulated cycle of the heart. The extent of motion may be represented as a fraction of the inflow-to-outflow length of the tube <NUM>. For example, the tube <NUM> may have a length in the axial direction between the inflow and outflow ends, and the maximum displacement of the tube <NUM> during a single cycle of the heart may be between about <NUM>% and about <NUM>%, including about <NUM>%, about <NUM>%, or about <NUM>% of the length of the tube <NUM>. In a healthy heart, there is typically relative motion between the ventricular wall and the valve annulus. The above-described features may allow for this natural relative motion to be recreated, whereas in other implant features, the relative motion might not be recreated.

Prosthetic heart valves intended for use in replacing a tricuspid (i.e., right atrioventricular) valve may include additional or alternative features than those described above particularly suited for use in the tricuspid space. For example, one concern that is of particular interest with tricuspid valve replacements is the fact that the AV node is typically located within the right atrium, and prosthetic tricuspid valves with an atrial cuff may be at risk of pressing against the AV node which may disturb the natural conduction system of the heart. Further, the tricuspid valve annulus is typically (but not necessarily always) larger than the annuli of the remaining heart valves (mitral, aortic, and pulmonary). Thus, while anchoring is almost always a relevant concern for a prosthetic heart valve, the concern may be heightened in the case of a prosthetic tricuspid valve. Various prosthetic tricuspid valves are described below which may address one or both of the above-noted issues.

<FIG> illustrates a highly schematic view of a prosthetic tricuspid valve system <NUM> implanted in a native tricuspid valve, with the heart being shown in a cutaway view. The prosthetic tricuspid valve system <NUM> may generally include three components, including a prosthetic valve <NUM> to provide the replacement valve functionality, an anchor <NUM> to serve as an anchor point for the prosthetic tricuspid valve system <NUM>, and a connecting line or tether <NUM> to couple the prosthetic valve <NUM> to the anchor <NUM>.

<FIG> is an isolated schematic view of the prosthetic valve <NUM> of the valve system <NUM>. The prosthetic valve <NUM> may include a collapsible and expandable stent or frame <NUM>. Frame <NUM> may be formed of a shape memory metal or metal alloy such as Nitinol, and may be formed as a braided mesh or an integral member, for example laser cut from a tube of Nitinol and then heat treated to establish the desired shape in the expanded condition. The frame <NUM>, when in the expanded condition shown in <FIG>, may include a main portion that is generally cylindrical, a set of prosthetic leaflets <NUM> being received within and coupled to the main portion. The prosthetic leaflets <NUM> may be substantially similar or identical to prosthetic leaflets <NUM> described above. It should be understood that, in the view of <FIG>, the outflow end is toward the bottom of the view while the inflow end is toward the top of the view. At the inflow end of the prosthetic heart valve <NUM>, the main portion of the frame <NUM> may transition to a connector <NUM>, the connector <NUM> coupling the tether <NUM> to the frame <NUM>. Briefly referring to <FIG>, the transition may include a plurality (e.g., three) of individual struts that have first ends connected to the main portion of the frame <NUM> and which converge to a central portion which is the connector <NUM>. In some embodiments, the connector <NUM> is not a separate structure and is simply the point of fixation between the tether <NUM> and the frame <NUM>. However, specialized features may be provided for connector <NUM>, an example of which is described in greater detail below.

Referring back to <FIG>, the prosthetic valve <NUM> may also include an outer frame <NUM> coupled to the inner frame <NUM>. In some embodiments, the outer frame <NUM> may be sutured or otherwise fastened to the inner frame <NUM>. In other embodiments, the outer frame <NUM> and the inner frame <NUM> may not be separate structures, but rather formed integrally, for example via laser cutting from a single tube of Nitinol. The prosthetic valve <NUM> may be asymmetric and have a single intended orientation for implantation. The outer frame <NUM> may include two main valve anchoring features, including a hook <NUM> and a shelf <NUM>. The hook <NUM> may be referred to as a right ventricular outflow tract ("RVOT") hook <NUM>, and is intended to hook over the outflow side of the native tricuspid valve leaflets adjacent to the RVOT, which is generally the area through which blood flows from the right ventricle through the pulmonary valve. The intended position of the RVOT hook <NUM> is best shown in <FIG>. In the expanded or deployed condition, the RVOT hook <NUM> may extend from the main portion of the frame <NUM> in the outflow direction, extending radially outward from the center of the prosthetic valve <NUM> and then hooking back toward the inflow direction of the prosthetic valve <NUM>. The shelf <NUM>, which may be referred to as a posterior shelf, is generally similar in overall shape and structure to the RVOT hook <NUM>, but extends from the diametrically opposed portion of the prosthetic valve <NUM>, as best shown in <FIG> and <FIG>. As with RVOT hook <NUM>, posterior shelf <NUM> is positioned on the outflow or ventricular side of the native tricuspid valve after deployment, but extends generally toward the right ventricular wall (the ventricular wall opposite the intraventricular septum). Also, as with RVOT hook <NUM>, posterior shelf <NUM> may extend from the main portion of the frame <NUM> in the outflow direction, extending radially outward from the center of the prosthetic valve <NUM> and then hooking back toward the inflow direction of the prosthetic valve <NUM>.

Referring again to <FIG>, the structure and shape of the outer frame <NUM> are shown and described in greater detail below. <FIG> is a top view of prosthetic heart valve <NUM>, as viewed from the inflow-to-outflow direction. In the embodiment of <FIG>, the outer frame <NUM> is a separate component from the frame <NUM>, and generally surrounds the frame <NUM> and is fastened to the frame <NUM> (e.g., via sutures). The portions of the outer frame <NUM> between the RVOT hook <NUM> and the posterior shelf <NUM> (e.g., the top and bottom portions in the view of <FIG>) may be relatively thin and mainly intended to provide a structure that connects to the RVOT hook <NUM> and posterior shelf <NUM>. The RVOT hook <NUM> may extend a distance radially away from the center of the prosthetic heart valve <NUM> greater than the radial distance that the posterior shelf <NUM> extends from the center of the prosthetic heart valve <NUM>. However, the RVOT hook <NUM> may be narrower compared to the posterior shelf <NUM>. In particular, the width of the posterior shelf <NUM>, measured in a direction orthogonal to the flow direction of the prosthetic valve <NUM> and perpendicular to the directions in which the RVOT hook <NUM> and posterior shelf <NUM> extend, may be greater than the width of the RVOT hook <NUM> measured in the same direction. The RVOT hook <NUM> and posterior shelf <NUM>, when the prosthetic heart valve <NUM> is deployed in the native tricuspid valve annulus, mainly function to provide a force that counters the tension from tether <NUM>, described in greater detail below. In other words, although the RVOT hook <NUM> and posterior shelf <NUM> may assist with sealing the prosthetic valve <NUM> against the native tricuspid valve annulus, the main purpose is to provide an anchoring force against migration of the prosthetic heart valve <NUM> into the right atrium. Although not shown, the prosthetic heart valve <NUM> may include any suitable skirt or sealing member on outer surfaces thereof to contact the native anatomy to help with sealing against paravalvular leak.

As should be understood from <FIG> and the corresponding description, the only anchoring features of the prosthetic heart valve <NUM> that result in direct contact with the native tricuspid valve annulus are the RVOT hook <NUM> and posterior shelf <NUM>, which contact the outflow or ventricular side of the native tricuspid valve. Also, to the extent that the self-expansion force of the main body of the prosthetic heart valve <NUM> in the native tricuspid annulus provides additional anchoring, the contact is generally only with the inner surface of the native tricuspid valve annulus. One benefit is that the prosthetic heart valve <NUM> may be anchored within the native tricuspid valve without any atrial cuff that is typical of a prosthetic tricuspid valve. In other words, there is no flared atrial end that sits in contact with the inflow or atrial side of the prosthetic tricuspid valve. As noted above, the AV node is typically located on the atrial side of the native tricuspid valve annulus near the atrial septum. The anchoring described and shown in connection with <FIG>completely avoids contact with the AV node, reducing the likelihood of conduction disturbances that might result in the prosthetic heart valve <NUM> contacting or otherwise pressing against the AV node.

<FIG> illustrates the anchor <NUM> of the tricuspid valve system <NUM> deployed within the superior vena cava SVC. Anchor <NUM> may take the form of a collapsible and expandable stent. In some embodiments, the anchor <NUM> may be balloon expandable and formed of a plastically expandable material such as stainless steel or cobalt chrome. In other embodiments, the anchor <NUM> may be self-expandable and formed of a shape memory material such as Nitinol. Preferably, anchor <NUM> is generally cylindrical when expanded and thus does not disrupt (or does not materially disrupt) the flow of blood through the superior vena cava SVC. If the anchor <NUM> is self-expandable, the anchor <NUM> is preferably oversized so that, in the absence of applied forces, the outer diameter of the anchor <NUM> is larger than the inner diameter of the superior vena cava SVC. In other words, the anchor <NUM> may be "oversized" relative to the superior vena cava SVC so that, when the anchor <NUM> self-expands into the superior vena cava SVC, the anchor <NUM> at least slightly deforms the shape of the superior vena cava SVC to help prevent axial migration of the anchor <NUM>. This local deformation of the superior vena cava SVC can be seen in <FIG>. If the anchor <NUM> is balloon expandable, the balloon (or other mechanism that forces the anchor <NUM> to radially expand), may be used to expand the anchor <NUM> until it has a diameter that is slightly larger than the natural inner diameter of the superior vena cava SVC.

Still referring to <FIG>, although the anchor <NUM> may be generally cylindrical in the expanded condition, the anchor preferably includes a feature to assist with the connection of the tether <NUM> to the anchor <NUM>. For example, as shown in <FIG>, the outflow end of the anchor <NUM> (which is positioned closest to the right atrium upon deployment into the superior vena cava SVC) may include an arch <NUM> that the tether <NUM> may be looped around, as described in greater detail below. <FIG> illustrates the anchor <NUM> in isolation in an expanded condition, showing the arch <NUM> that extends beyond the outflow end of the main cylindrical portion of the anchor <NUM>. In the particular example, arch <NUM> may be formed as a single strut or strand of metal that has ends coupled to diametrically opposed points of the anchor <NUM>, similar to a handle of a bucket. Although arch <NUM> is shown as a generally arcuate member, in some embodiments it may be more "V"-shaped which may assist with the arch <NUM> more easily collapsing for delivery. It should be understood that other shapes and configurations of arch <NUM> may be suitable. And although arch <NUM> is described in connection with looping of the tether <NUM> around the arch <NUM> to connect the tether <NUM> to the anchor <NUM>, as described in greater detail below, it should be understood that any mechanism for connecting the tether <NUM> to the anchor <NUM> may be suitable.

<FIG> illustrate different stages in the delivery and deployment of prosthetic tricuspid valve system <NUM> into a patient's heart. During an exemplary delivery and deployment of the prosthetic tricuspid valve system <NUM>, the anchor <NUM> may be loaded into a catheter <NUM> of a delivery device in a collapsed condition. The catheter <NUM> may be passed into the patient, for example through an access site in the femoral vein, and the catheter <NUM> may be advanced through the inferior vena cava IVC, into the right atrium, and then into the superior vena cava SVC. When the distal end of the catheter <NUM> has reached the desired distance within the superior vena cava SVC, the anchor <NUM> may be deployed from the catheter <NUM> and transitioned into the expanded condition shown in <FIG>. In one example, the anchor <NUM> may be loaded over an inflatable balloon and the balloon may be inflated to force the anchor <NUM> to expand into the superior vena cava SVC. In another example, the anchor <NUM> may be advanced distally relative to the distal end of the catheter <NUM>, and the anchor <NUM> will self-expand as the catheter <NUM> uncovers the anchor <NUM>. The mechanism by which the anchor <NUM> is advanced relative to the catheter <NUM> may be any suitable mechanism. For example, an interior pusher may be pushed distally to push the anchor <NUM> out of the catheter <NUM>. In another embodiment, the anchor <NUM> may be releasably coupled to an inner catheter shaft, and the catheter <NUM> may be withdrawn proximally relative to the anchor <NUM> until the anchor <NUM> self-expands away from the inner catheter shaft. With either option, the anchor <NUM> is preferably expanded to a size that has a larger diameter than the natural inner diameter of the superior vena cava SVC, as described above, with the arch <NUM> facing in the outflow direction (i.e., toward the right atrium). In this embodiment, the stent <NUM> is delivered in isolation without being connected to either the tether <NUM> or the prosthetic heart valve <NUM> at the time of deployment of the stent <NUM>.

After the anchor <NUM> is deployed, the prosthetic valve <NUM> may be delivered and deployed next. In some embodiments, the same catheter <NUM> that delivered the anchor <NUM> may be used to deliver the prosthetic valve <NUM>. For example, the prosthetic valve <NUM> may be pre-loaded into the catheter <NUM> in a collapsed condition in a position proximal to the anchor <NUM>. In other embodiments, the catheter used to deliver the prosthetic valve <NUM> may be a separate catheter. Although either option is feasible, for brevity, the same part number <NUM> is used to describe the catheter that delivers the prosthetic heart valve <NUM>. In either embodiment, after the anchor <NUM> is deployed satisfactorily, the catheter <NUM> may be positioned or re-positioned so that the distal end of the catheter <NUM> is at or adjacent to the native tricuspid valve. When loaded into the catheter <NUM>, the prosthetic valve <NUM> is oriented so that the RVOT hook <NUM> and the posterior shelf <NUM> are at the leading end of the prosthetic valve <NUM>. Preferably, while loaded into the catheter <NUM>, the RVOT hook <NUM> and posterior shelf <NUM> do not radially overlap the main body of frame <NUM>.

As best shown in <FIG>, once the catheter <NUM> is at the desired position relative to the native tricuspid valve, the prosthetic heart valve <NUM> may be deployed. Similar to the anchor <NUM>, the deployment of the prosthetic heart valve <NUM> may include withdrawing the catheter <NUM> while the prosthetic heart valve <NUM> maintains its position, pushing the prosthetic heart valve <NUM> distally out of the catheter <NUM>, or a combination of the two. The first portions of the prosthetic heart valve <NUM> that exit the catheter <NUM> are the RVOT hook <NUM> and the posterior shelf <NUM>. As they exit the catheter <NUM>, and the catheter <NUM> no longer constrains them, the RVOT hook <NUM> and posterior shelf <NUM> will tend to revert to their shape-set conditions, causing the RVOT hook <NUM> and posterior shelf <NUM> to "hook" backward after exiting the catheter <NUM>. As the RVOT hook <NUM> and posterior shelf <NUM> hook backward during deployment, they hook over the outflow portion of the native tricuspid valve annulus, which may include native tricuspid valve leaflets.

Prior to describing the remaining portions of the exemplary delivery and deployment procedure, the tether <NUM> is described briefly. Tether <NUM> may be in the form of any string-like or wire-like structure that is biocompatible and is capable of withstanding tension that would otherwise tend to push the prosthetic heart valve <NUM> into the right ventricle. For example, tether <NUM> may be a metal structure, such as a monofilament or a multifilament, including for example Nitinol. Tether <NUM> may alternatively be formed of a polymer, such as one or more strands or filaments or threads of PE, PTFE, UHMWPE, etc. In one exemplary embodiment, the tether <NUM> is formed as a braided polymer. The tether <NUM> may include a first end portion that is fixed to the prosthetic valve <NUM> prior to the prosthetic heart valve <NUM> being loaded into the catheter <NUM>. For example, the connector <NUM> of the frame <NUM> may include a generally cylindrical stent section which may be sized to receive an end of the tether <NUM>, with the connector <NUM> being clamped over and/or fastened (e.g., by sutures) to the tether <NUM> positioned therein. Examples of connectors <NUM> for receiving tethers are described in greater detail in <CIT>. Thus, while the prosthetic heart valve <NUM> is within the catheter <NUM> being delivered, the tether <NUM> may already be coupled or otherwise fixed to the prosthetic heart valve <NUM> with the tether <NUM> trailing (or being positioned generally proximal to) the prosthetic heart valve <NUM>. The tether <NUM> may have a length to extend to a handle of a delivery device or beyond a handle during the delivery of the prosthetic heart valve <NUM>.

Referring again to <FIG>, as the catheter <NUM> is withdrawn relative to the prosthetic heart valve <NUM>, the RVOT hook <NUM> and posterior shelf <NUM> may begin to hook backward and into contact with the ventricular or outflow side of the native tricuspid valve annulus. This contact is generally responsible for the prosthetic heart valve <NUM> resisting migration into the right atrium. As the catheter <NUM> is withdrawn farther relative to the prosthetic heart valve <NUM>, the remaining portions of the prosthetic heart valve <NUM> (including the main body of the frame <NUM> and the prosthetic leaflets <NUM>) may expand within the tricuspid valve annulus and begin to replace the functionality of the native tricuspid valve. <FIG> illustrates a further step in the procedure in which the catheter <NUM> is further withdrawn and the prosthetic heart valve <NUM> is allowed to fully expand into the native tricuspid valve. The catheter <NUM> may be maneuvered so that the tether <NUM>, which is already fixed to the prosthetic heart valve <NUM> and which extends through the catheter <NUM> proximally, is looped around the arch <NUM> of the anchor <NUM>. After the tether <NUM> is looped around the arch <NUM>, the tether <NUM> may be pulled proximally to tension the tether <NUM>, for example by manipulating the free end of the tether that is coupled to the delivery device or otherwise available for manipulation outside the patient's body. As the tether <NUM> is being tensioned, the arch <NUM> generally acts like a pulley, and tension on the tether <NUM> may be increased pulling the RVOT hook <NUM> and posterior shelf <NUM> tighter against the outflow side of the native valve annulus. Once the tether <NUM> is tensioned to the desired amount, it may then be affixed to the arch <NUM> of the anchor <NUM>, for example via a knot, a separate accessory feature, or a barb-like feature built into the arch <NUM>. Once the tether <NUM> is fixed to the arch <NUM>, the tension on the tether <NUM> is effectively "locked," with the tether <NUM> preventing the prosthetic heart valve <NUM> from migrating into the right ventricle, and the RVOT hook <NUM> and posterior shelf <NUM> preventing the prosthetic heart valve <NUM> from migrating into the right atrium. In other words, the prosthetic heart valve <NUM> may be fully and satisfactorily anchored in the native tricuspid valve without any stent structure hooked around or otherwise contacting the inflow side of the native tricuspid valve, particularly in the area of the AV node.

<FIG> is a schematic view of an alternate version of the anchor <NUM>' that includes a tether connection mechanism <NUM>' different than the arch <NUM> of <FIG>. A portion of anchor <NUM>' is shown in <FIG>, with the anchor <NUM>' converging to a tether connection mechanism <NUM>' generally in the form of a cylinder that the tether <NUM> passes through. A tine or barb <NUM>', which may be a piece of metal (e.g., Nitinol) that is integral with the remainder of the anchor <NUM>', extends upwardly and inwardly from the tether connection mechanism <NUM>'. Preferably, the tine or barb <NUM>' has a sharp tip capable of digging into the tether <NUM>, for example if the tether <NUM> is formed of a polymer. The tine <NUM>' is angled so that, if the tether <NUM> is pulled in a first direction T1 aligned with the angle of the tine <NUM>', the tether <NUM> can generally freely translate through the connection mechanism <NUM>', resulting in tension being added to the tether <NUM>. However, if the tether <NUM> is pulled in the opposite direction T2, for example after releasing force on the tether <NUM> while the tether is tensioned, the tine <NUM>' digs into the tether <NUM>, preventing the tether <NUM> from translating any significant distance in the direction T2. Thus, with the tine <NUM> angled so that the sharp tip is pointing superiorly, the tether <NUM> may be pulled to the desired tension, and then upon reaching the desired tension, the tether <NUM> may be released at which point the tine <NUM>' will engage the tether <NUM> and lock the tether <NUM> at the desired tension.

In some embodiments, after the tether <NUM> has been tensioned to the desired amount and fixed to the anchor <NUM> or <NUM>' at the desired tension, the remaining length of the tether <NUM> extending beyond the anchor <NUM> or <NUM>' may be cut and removed from the body, for example via a cautery tool introduced into the heart.

In some embodiments, it may be desirable for the prosthetic heart valve <NUM> to be rotatable about a central longitudinal axis prior to or during deployment. For example, the RVOT hook <NUM> is intended to be positioned at or near the RVOT, while the posterior shelf <NUM> is intended to be positioned toward the ventricular wall opposite the interventricular septum. If the RVOT hook <NUM> and posterior shelf <NUM> are not in the desired rotational orientation prior to (or during) deployment, it may be desirable to have a mechanism to rotate the prosthetic heart valve <NUM> to the desired rotational orientation relative to the native tricuspid valve. If the prosthetic heart valve <NUM> is releasably coupled to an internal shaft or catheter during deployment, that internal shaft may be rotatable (e.g., via manipulation of a handle of the delivery device) to re-orient the prosthetic heart valve <NUM> into the desired rotational position.

Claim 1:
A prosthetic heart valve (<NUM>) comprising:
a collapsible and expandable frame (<NUM>) that, in an expanded condition, includes a central portion (<NUM>), an atrial portion (<NUM>) flaring radially outwardly from the central portion (<NUM>), and a ventricular portion (<NUM>) flaring radially outwardly from the central portion (<NUM>);
a tube (<NUM>) positioned within the frame (<NUM>), the tube having a lumen extending along a longitudinal axis from the atrial portion (<NUM>) toward the ventricular portion (<NUM>) of the frame (<NUM>), wherein the tube (<NUM>) is formed of tissue or fabric;
a plurality of prosthetic leaflets (<NUM>) directly coupled to the tube (<NUM>) to form a valve, the valve allowing blood to flow through the lumen of the tube in an antegrade direction but substantially blocking blood from flowing through the lumen of the tube in a retrograde direction; and
a plurality of cords (<NUM>) each having a first portion coupled to the frame (<NUM>) and a second portion coupled to the tube (<NUM>), each of the plurality of cords (<NUM>) extending in a radial direction toward the longitudinal axis,
wherein the tube (<NUM>) excludes any metal structure directly attached to the tube (<NUM>).