Patent Description:
The human heart can suffer from various valvular diseases. These valvular diseases can result in significant malfunctioning of the heart and ultimately require replacement of the native valve with an artificial valve. There are a number of known artificial valves and a number of known methods of implanting these artificial valves in humans.

Various surgical techniques may be used to replace or repair a diseased or damaged native valve. Due to stenosis and other heart valve diseases, thousands of patients undergo surgery each year wherein the defective native heart valve is replaced by a prosthetic valve. Another less drastic method for treating defective valves is through repair or reconstruction, which is typically used on minimally calcified valves. The problem with surgical therapy is the significant risk it imposes on these chronically ill patients with high morbidity and mortality rates associated with surgical repair.

When the native valve is replaced, surgical implantation of the prosthetic valve typically requires an open-chest surgery during which the heart is stopped and patient placed on cardiopulmonary bypass (a so-called "heart-lung machine"). In one common surgical procedure, the diseased native valve leaflets are excised and a prosthetic valve is sutured to the surrounding tissue at the native valve annulus. Because of the trauma associated with the procedure and the attendant duration of extracorporeal blood circulation, some patients do not survive the surgical procedure or die shortly thereafter. It is well known that the risk to the patient increases with the amount of time required on extracorporeal circulation. Due to these risks, a substantial number of patients with defective native valves are deemed inoperable because their condition is too frail to withstand the procedure. By some estimates, more than <NUM>% of the subjects suffering from valve stenosis who are older than <NUM> years cannot be operated on for valve replacement.

Because of the drawbacks associated with conventional open-heart surgery, percutaneous and minimally-invasive surgical approaches are garnering intense attention. In one technique, a prosthetic valve is configured to be implanted in a much less invasive procedure by way of catheterization. For instance, <CIT> and <CIT> describe collapsible transcatheter prosthetic heart valves that can be percutaneously introduced in a compressed state on a catheter and expanded in the desired position by balloon inflation or by utilization of a self-expanding frame or stent.

An important design parameter of a transcatheter prosthetic heart valve is the diameter of the folded or crimped profile. The diameter of the crimped profile is important because it directly influences the physician's ability to advance the transcatheter prosthetic heart valve through the femoral artery or vein. More particularly, a smaller profile allows for treatment of a wider population of patients, with enhanced safety.

<CIT> describes an implantable prosthetic valve that has an upper frame section and a lower frame section. The upper frame section has a plurality of struts and a first leaflet receiving surface at a lower portion of the upper frame section. The lower frame section has a second leaflet receiving surface at an upper portion of the lower frame section. An edge of a flexible leaflet is disposed between the first and second leaflet receiving surfaces to attach the leaflet to the upper and lower frame sections.

<CIT> describes a prosthetic heart valve including a valve frame having a wireform portion and a stent portion. The wireform and stent portions are undetachably coupled together via a plurality of upright struts so as to form a one-piece prosthetic heart valve frame. Alternatively, a self-expanding wireform portion and a balloon-expandable stent portion are coupled together via one or more leaflets and a subassembly having a flexible leaflet support stent and a sealing ring. The wireform portion includes cusps and commissures configured to support a plurality of leaflets. The prosthetic valve is radially collapsible for minimally invasive and/or transcatheter delivery techniques.

<CIT> describes a prosthetic heart valve that is circumferentially collapsible. The valve re-expands to operating size at the implant site in the patient. A frame structure of the valve includes a restraining structure that can help to push one or more of the patient's native heart valve leaflets radially outwardly so that this native leaflet tissue does not interfere with the operation or service life of the prosthetic valve.

<CIT> describes a prosthetic heart valve and a heart valve delivery apparatus for delivery of the prosthetic heart valve to a native valve site via the human vasculature. The delivery apparatus is particularly suited for advancing a prosthetic valve through the aorta (i. , in a retrograde approach) for replacing a diseased native aortic valve. A self-expanding valve comprises an expandable stent that is shaped to maintain the valve in the aortic annulus without anchors or retaining devices that engage the surrounding tissue. A delivery apparatus for delivering s self-expanding prosthetic valve can be configured to allow controlled and precise deployment of the valve from a valve sheath so as to minimize or prevent jumping of the valve from the valve sheath.

The present invention is defined in independent claims <NUM> and <NUM>.

As set forth in independent claim <NUM>, the present invention relates to a radially and balloon-expandable frame for a prosthetic valve, wherein the frame, when viewed in a flattened state thereof, comprises a plurality of struts, the struts extending longitudinally, being sinusoidal-shaped or undulating, and connecting to each other at nodes so as to define a plurality of open cells arranged in plural rows along the longitudinal flow axis of the frame; wherein the plural rows consist of one inflow row of cells, one outflow row of cells, and one or two intermediate rows of cells between the inflow and outflow rows of cells; wherein the outflow row includes six cells, and the inflow row and each intermediate row include twelve cells each, wherein three circumferentially spaced, longitudinally extending commissure attachment posts are interspaced between a plurality of frame apices, and wherein the frame is suitable for being balloon-expanded in a shape defined by: an inflow end portion of the frame increasing in diameter from a diameter D1 at an inflow end of the frame to a relatively larger diameter D2 at a distance spaced from the inflow end of the frame, an intermediate portion defining a landing zone for positioning the intermediate portion within the native annulus when the prosthetic valve is deployed, the intermediate portion initially decreasing in diameter from the diameter D2 to a relatively smaller diameter D3 at a middle section of the intermediate portion and then increasing in diameter to a diameter D4 proximate an outflow end of the frame, an outflow portion of the frame decreasing in diameter from the diameter D4 at an outflow end of the intermediate portion to a diameter D5 at the outflow end of the frame, the diameter D5 being defined by upper free ends of the commissure attachment posts, and the commissure attachment posts extending inwardly at an angle of about <NUM> degrees to about <NUM> degrees with respect the flow axis A.

As set forth in independent claim <NUM>, the present invention further relates to a prosthetic valve configured to be radially compressed to a crimped state for delivery into the body of a patient and radially expandable from the crimped state to an expanded state once positioned at the desired implantation location within the body, the prosthetic valve comprising: a frame as defined in any of claims <NUM> to <NUM>; and a valvular structure forming a plurality of commissures, the number of commissures corresponding to the number of commissure attachment posts to which the commissures are attached.

Preferred configurations of the claimed invention are defined in dependent claims <NUM> to <NUM> and <NUM> to <NUM>.

Also described herein are related aspects, examples, embodiments and arrangements useful for understanding the claimed invention, and which do not necessarily constitute embodiments of the claimed invention. The subject-matter for which protection is sought is defined by the claims.

The present disclosure is directed to embodiments of catheter-based prosthetic heart valves. A prosthetic heart valve according to the present disclosure comprises a radially collapsible and expandable annular frame and a leaflet structure comprising a plurality of leaflets mounted within the frame. The frame in particular embodiments can have commissure attachment portions that are configured to support the commissures of the leaflets at locations spaced radially inwardly toward the longitudinal flow axis of the prosthetic valve relative to the frame portions circumscribing the moveable portions of the leaflets. When the leaflets open under pressure of blood flowing through the prosthetic valve, the moveable portions of the leaflets are retained at positions spaced inwardly from the inner surface of the frame to protect against abrasion of the leaflets.

In one representative embodiment, a prosthetic valve comprises a radially collapsible and expandable annular frame. The frame has a plurality of angularly spaced commissure attachment portions and a plurality of lobed portions extending between the commissure attachment portions. The frame also has an inlet end and an outlet end. A leaflet structure comprises a plurality of leaflets, each leaflet comprising opposing side portions and an upper edge extending between the side portions. Each side portion is secured to an adjacent side portion of another leaflet to form commissures of the leaflet structure, each commissure being attached to one of the commissure attachment portions of the frame. The leaflets are configured to move between an open position to allow blood to flow through the prosthetic valve from the inlet end to the outlet end and a closed position to inhibit the flow of blood through the prosthetic valve from the outlet end to the inlet end, wherein the upper edges of the leaflets are spaced radially inwardly of the lobed portion of the frame when the leaflets are in the open position.

In another representative embodiment, a prosthetic valve comprises a radially collapsible and expandable annular frame. The frame comprises an inlet portion and an outlet portion, the outlet portion comprising a plurality of angularly spaced, cantilevered commissure attachment posts extending radially inwardly toward a longitudinal flow axis of the prosthetic valve. A leaflet structure comprises a plurality of leaflets, each leaflet comprising opposing side portions, a scalloped upper edge extending between the side portions, and a scalloped lower edge extending between the side portions. Each side portion is secured to an adjacent side portion of another leaflet to form commissures of the leaflet structure, each commissure being attached to one of the commissure attachment posts. The leaflets are configured to move between an open position to allow blood to flow through the prosthetic valve from the inlet portion to the outlet portion and a closed position to inhibit the flow of blood through the prosthetic valve from the outlet portion to the inlet portion, wherein the upper edges of the leaflets are spaced radially inwardly of the frame when the leaflets are in the open position such that a gap is formed between the upper edge of each leaflet and the frame.

In another representative embodiment, a prosthetic valve comprises a radially collapsible and expandable annular frame. The frame has a plurality of angularly spaced commissure attachment posts, each commissure attachment post comprising at least two cantilevered struts spaced apart from each other to define a leaflet-receiving gap. A leaflet structure comprises a plurality of leaflets, each leaflet comprising opposing side portions and an upper edge extending between the side portions. Each side portion is secured to an adjacent side portion of another leaflet to form commissures of the leaflet structure. Each commissure extends through the leaflet-receiving gap of a respective commissure attachment post, and the struts of the commissure attachment post are compressed toward each to clamp the commissure between the struts.

In another representative embodiment, a prosthetic valve comprises a radially collapsible and expandable annular frame that is plastically expandable. The frame comprises a plurality of angularly spaced commissure attachment posts. A leaflet structure comprises a plurality of leaflets, each leaflet comprising opposing side portions, wherein each side portion is secured to an adjacent side portion of another leaflet to form commissures of the leaflet structure, each commissure being attached to one of the commissure attachment posts. The commissure attachment posts are configured to deflect radially inwardly toward a longitudinal flow axis of the prosthetic valve when first subjected to closing forces of the leaflets immediately following implantation of the prosthetic valve and then remain in the deflected position during subsequent closing and opening cycles of the prosthetic valve.

The present disclosure is directed to embodiments of catheter-based prosthetic heart valves. Several exemplary embodiments of prosthetic heart valves are disclosed herein and shown in the attached figures. These embodiments should not be construed as limiting in any way. <FIG> show frame embodiments in accordance to the invention.

<FIG> is a perspective view of a prosthetic heart valve <NUM>, according to one embodiment. The illustrated prosthetic valve is adapted to be implanted in the native aortic annulus, although in other embodiments it can be adapted to be implanted in the other native annuluses of the heart. The prosthetic valve <NUM> can have three main components: a stent, or frame, <NUM>, a valvular structure <NUM>, and an inner skirt <NUM>. The prosthetic valve <NUM> is configured to be radially compressed to a crimped state for delivery into the body of a patient and radially expandable from the crimped state to an expanded state once positioned at the desired implantation location within the body.

The valvular structure <NUM> can comprise three leaflets <NUM>, collectively forming a leaflet structure, which can be arranged to collapse in a tricuspid arrangement, as best shown in <FIG>. The leaflets <NUM> can be formed of pericardial tissue (e.g., bovine pericardial tissue), biocompatible synthetic materials, or various other suitable natural or synthetic materials as known in the art and described in <CIT>.

<FIG> shows a flattened view of the bare frame <NUM> and <FIG> shows a perspective view of the bare frame as laser cut from a tubular member, prior to any shape forming. The frame <NUM> can be formed with a plurality of circumferentially spaced commissure supports <NUM> (three in the illustrated embodiment), each of which comprises two axial struts <NUM> defining a respective slot, or commissure window, <NUM> therebetween that is adapted to mount the commissures of the valvular structure <NUM> to the frame, as described in greater detail below. The frame <NUM> can be made of any of various suitable plastically-expandable materials (e.g., stainless steel, etc.) or self-expanding materials (e.g., Nitinol) as known in the art. When constructed of a plastically-expandable material, the frame <NUM> (and thus the prosthetic valve <NUM>) can be crimped to a radially compressed state on a delivery catheter and then expanded inside a patient by an inflatable balloon or equivalent expansion mechanism. When constructed of a self-expandable material, the frame <NUM> (and thus the prosthetic valve <NUM>) can be crimped to a radially compressed state and restrained in the compressed state by insertion into a sheath or equivalent mechanism of a delivery catheter. Once inside the body, the prosthetic valve can be advanced from the delivery sheath, which allows the prosthetic valve to expand to its functional size.

Suitable plastically-expandable materials that can be used to form the frame <NUM> include, without limitation, stainless steel, a nickel based alloy (e.g., a cobalt-chromium or a nickel-cobalt-chromium alloy), polymers, or combinations thereof. In particular embodiments, frame <NUM> is made of a nickel-cobalt-chromium-molybdenum alloy, such as MP35N™ (tradename of SPS Technologies), which is equivalent to UNS R30035 (covered by ASTM F562-<NUM>). MP35N™/UNS R30035 comprises <NUM>% nickel, <NUM>% cobalt, <NUM>% chromium, and <NUM>% molybdenum, by weight. It has been found that the use of MP35N to form frame <NUM> provides superior structural results over stainless steel. In particular, when MP35N is used as the frame material, less material is needed to achieve the same or better performance in radial and crush force resistance, fatigue resistances, and corrosion resistance. Moreover, since less material is required, the crimped profile of the frame can be reduced, thereby providing a lower profile prosthetic valve assembly for percutaneous delivery to the treatment location in the body.

The frame <NUM> can also include a plurality of axially extending posts <NUM> extending from the outflow end of the frame. The posts <NUM> are used to form a releasable connection between the prosthetic valve <NUM> and corresponding components at the distal end of a delivery catheter to retain the prosthetic valve at the end of the delivery catheter until the prosthetic valve is properly positioned at its target deployment location within the body. The posts <NUM> typically are used when the frame is a self-expanding frame since there is no balloon to retain the prosthetic valve in place during deployment. If the frame is a plastically-expandable frame that is deployed with a balloon or similar expansion device, the posts <NUM> typically are not provided. Details of a delivery device that is configured to retain a self-expandable prosthetic valve via posts <NUM> is disclosed in <CIT>.

Referring to <FIG>, the frame <NUM> includes an inflow end <NUM>, an outflow end <NUM>, a lower portion <NUM> and an upper portion <NUM>. As best shown in <FIG>, the upper portion <NUM> has a tri-lobed cross-sectional shape in a plane perpendicular to the longitudinal axis A of the prosthetic valve at least when the frame is in it expanded state. The upper portion <NUM> defines three lobed-shaped portions <NUM> that mimic the shape of the sinuses of the aortic root. The lower portion <NUM> of the frame desirably has a generally conical or flared shape that tapers from the inflow end <NUM> toward the upper portion <NUM> to assist in anchoring the prosthetic valve to the native annulus once implanted. In other embodiments, the lower portion <NUM> of the frame can have an overall cylindrical shape from the inflow end <NUM> to the lower end of the upper portion <NUM>. If the frame <NUM> is constructed of a self-expandable material (e.g., Nitinol), then the frame can be shape set to assume the shape shown in <FIG> when the frame radially expands to its expanded state. If the frame <NUM> is constructed of a plastically-expandable material, then a specially designed delivery device can be used to cause the frame to expand to the shape shown in <FIG>. One such delivery device is shown in <FIG> and described below.

The leaflet assembly <NUM> defines three commissures <NUM> where the adjacent sides of the leaflets <NUM> are secured to each other. The commissures <NUM> desirably are secured to the upper portion <NUM> of the frame <NUM> at locations closest to the longitudinal axis A of the prosthetic valve (which correspond to the locations around the frame where the adjacent ends of the lobed portions <NUM> meet). The frame <NUM> can be provided with commissure window frame portions <NUM> at these locations of the frame to facilitate attachment of the commissures <NUM> to the frame. Each commissure <NUM> can be formed by securing each leaflet tab <NUM> (<FIG>) with an adjacent tab <NUM> of another leaflet <NUM>. The commissures <NUM> can be secured to the frame by inserting each pair of leaflet tabs <NUM> through a respective slot <NUM> in a frame portion <NUM>, and securing the leaflet tabs <NUM> to the axial struts <NUM>, such as with sutures. Further details regarding various techniques for securing the commissures to the window frame portions <NUM> are disclosed in co-pending <CIT> (Application No. <CIT>.

<FIG> shows a leaflet <NUM> superimposed over a known leaflet <NUM> for the same size prosthetic valve. As shown, the leaflet <NUM> in the illustrated embodiment includes a substantially V-shaped lower edge extending between the lower edges of the tabs <NUM> and a gently curved, or scalloped, upper edge <NUM> extend between the upper edges of the tabs <NUM>. Because the commissures <NUM> are secured to the frame <NUM> at locations spaced radially inwardly toward the longitudinal center axis A relative to the radially outermost sections of the lobed portions <NUM>, the width W of the leaflet (measured between opposing side edges at any location along the height H of the leaflet) can be much less than the width of the leaflet <NUM>. Similarly, the opposing sides of the lower edge <NUM> can have a greater taper (i.e., the width of the lower portion of the leaflet decreases at a greater rate from top to bottom) than the leaflet <NUM>. Consequently, the leaflets <NUM> are much smaller than typical conventional leaflets for the same size prosthetic valve, and therefore occupy much less space inside the prosthetic valve. As a result, the prosthetic valve <NUM> can be crimped to a smaller diameter for delivery.

An important design criterion of a prosthetic heart valve is to prevent or minimize contact between the movable portions of the leaflets and the inner surface of the frame. Repeated contact between the movable portions of the leaflets and the metal frame during operation of the prosthetic valve can cause premature wear and eventual failure of the leaflets. To mount a leaflet assembly to a frame having a cylindrical cross section, it is known, for example, to use additional metal struts or bars or additional layers of material to mount the commissures at locations spaced radially inward from the inner surface of the frame, which assists in preventing contact between the leaflets and the frame. Unfortunately, the use of additional components or additional layers of material for the mounting the commissures takes up valuable space inside of the frame and can limit the overall crimping profile of the prosthetic valve.

To address these concerns, the upper portion <NUM> of the frame <NUM> is shaped such that the commissure support portions of the frame are spaced radially inwardly toward the center axis A of the prosthetic valve relative to the adjacent sections of the frame, without using any additional components or layers of material inside the frame to offset the commissures from the inner surface of the frame. As noted above, the commissures <NUM> of the leaflets are supported at locations where the ends of the lobed portions <NUM> meet or converge. As a result, contact between the leaflets <NUM> and the inner surface of the lobed portions <NUM> can be avoided during operation of the prosthetic valve. As best shown in <FIG>, the upper free edges <NUM> of the leaflets are spaced inwardly from the lobed portions <NUM> by a distance G when the leaflets are open under systolic pressure. Advantageously, since the shape of the frame itself supports the commissures <NUM> radially inward of the frame sections between the commissure supports <NUM> without additional components inside of the prosthetic valve, the prosthetic valve <NUM> can be crimped to a smaller diameter for delivery.

Also due to the shape of the frame, during operation of the prosthetic valve, the commissure supports <NUM> of the frame can flex slightly radially inwardly and outwardly to reduce stress on the commissure attachment points (the locations were the leaflet tabs <NUM> are sutured to the frame). As noted above, the leaflets <NUM> can have a scalloped or curved upper edge <NUM>. As a result, the coaptation lines of the leaflets during diastole are lowered, creating a force vector acting downwardly (axially) from the commissures, which reduces stress on the commissure attachment points.

The prosthetic valve <NUM> desirably is implanted within a native annulus (e.g., the aortic annulus) such that the lower portion <NUM> of the frame serves as an anchor to retain the prosthetic valve against the native anatomy. Most of the upper portion <NUM> of the frame is positioned above the native annulus and has sufficient flexibility to attain the desired size and shape when expanded regardless of the shape of the native annulus. For example, in the case of an oval native annulus, the upper portion <NUM> of the frame can bend or flex relative to the lower portion <NUM> in order to expand to its desired functional size and shape to ensure proper operation of the prosthetic valve. In the case of a relatively small native annulus, which can prevent full deployment of the lower portion <NUM>, the upper portion can fully expand to its desired functional size and shape to ensure proper operation of the prosthetic valve.

The frame also is less sensitive to under deployment of the upper portion of the frame. Because the commissures of the leaflets are spaced radially inward from the lobed portions, a radial force applied to the upper portion will first compress the lobed portions in the radial direction before the commissures start to move inwardly. That is, the distance between the commissures <NUM> stays substantially constant as the lobed portions <NUM> are radially compressed a predetermined amount. In one implementation, the distance between the commissures <NUM> stays substantially constant when the diameter of the outflow end of the prosthetic valve is reduced by about <NUM>. Thus, if the upper portion of the frame is slightly under expanded due to the positioning of the prosthetic valve and/or the shape of the native annulus, the commissures <NUM> can still achieve their functional size, which promotes optimum leaflet performance and increased durability of the leaflets. Similarly, because leaflet function is not effected by a certain degree of under expansion of the frame, a prosthetic valve of a certain size can be implanted in a greater range of annulus sizes. Thus, the number of prosthetic valve sizes for treating a wide range of patients can be reduced.

The spaces between the skirt <NUM> and the outer surfaces of the leaflets <NUM> within the lobed portions <NUM> of the frame create artificial sinuses that are shaped similar to and mimic the Valsalva sinuses. Thus, when the leaflets close, backflow entering these artificial sinuses create a turbulent flow of blood along the upper surfaces of the leaflets. This turbulence assists in washing the leaflets and the skirt to minimize clot formation.

The commissures <NUM> can also be secured to a frame that does not have any window frame portions <NUM>. <FIG>, for example, shows a prosthetic valve <NUM>, according to another embodiment. The prosthetic valve <NUM> comprises a frame <NUM>, a valvular structure <NUM> mounted to the frame <NUM>, and a skirt <NUM>. Like the frame <NUM> described above, the frame <NUM> has a generally conical or flared lower portion <NUM> and a tri-lobed shaped upper portion <NUM> and functions in the manner described above. The frame <NUM> comprises a mesh like structure defining a plurality of openings or cells formed by the struts of the frame. The frame <NUM> has a substantially homogeneous or uniform structure in that the size and shape of all of the openings are substantially the same. The leaflets tabs <NUM> can be sutured to the struts of the frame <NUM> adjacent the outflow end and the lower edges <NUM> of the leaflets <NUM> (not shown in <FIG>) can be sutured to the skirt <NUM> with sutures, as described above in connection with prosthetic valve <NUM>. The frame <NUM> can also include posts <NUM> (not shown in <FIG>) for connection to a delivery apparatus.

The main functions of the skirt <NUM> are to assist in securing the valvular structure <NUM> to the frame <NUM> and to assist in forming a good seal between the prosthetic valve and the native annulus by blocking the flow of blood through the open cells of the frame <NUM> below the lower edge of the leaflets. The skirt <NUM> desirably comprises a tough, tear resistant material such as polyethylene terephthalate (PET), although various other synthetic or natural materials can be used. The thickness of the skirt desirably is less than <NUM> mil (<NUM> mil = <NUM>), and desirably less than <NUM> mil, and even more desirably about <NUM> mil. In particular embodiments, the skirt <NUM> can have a variable thickness, for example, the skirt can be thicker at its edges than at its center. In one implementation, the skirt <NUM> can comprise a PET skirt having a thickness of about <NUM> at its edges and about <NUM> at its center. The thinner skirt can provide for better crimping performances while still providing good perivalvular sealing.

As shown in <FIG>, the skirt <NUM> can be secured to the inside of frame <NUM> via sutures <NUM>. Valvular structure <NUM> can be attached to the skirt via one or more thin PET reinforcing strips (not shown) placed along the lower edges <NUM> of the leaflets, which enable a secure suturing and protects the pericardial tissue of the leaflet structure from tears. Valvular structure <NUM> can be sandwiched between skirt <NUM> and the thin PET strips. Sutures can be used to secure the PET strips and the leaflet structure <NUM> to the skirt <NUM> along a suture line <NUM> that tracks the curvature of the bottom edges <NUM> of the leaflets.

Referring to <FIG>, in contrast to known fabric skirts, the skirt <NUM> desirably is woven from a first set of fibers, or yarns or strands, <NUM> and a second set of fibers, or yarns or strands, <NUM>, both of which are non-perpendicular to the upper edge <NUM> and the lower edge <NUM> of the skirt. In particular embodiments, the first set of fibers <NUM> and the second set of fibers <NUM> extend at angles of about <NUM> degrees relative to the upper and lower edges <NUM>, <NUM>. The skirt <NUM> can be formed by weaving the fibers at <NUM> degree angles relative to the upper and lower edges of the fabric. Alternatively, the skirt can be diagonally cut from a vertically woven fabric (where the fibers extend perpendicular to the edges of the material) such that the fibers extend at <NUM> degree angles relative to the cut upper and lower edges of the skirt. As further shown in <FIG>, the opposing short edges <NUM>, <NUM> of the skirt desirably are non-perpendicular to the upper and lower edges <NUM>, <NUM>. For example, the short edges <NUM>, <NUM> desirably extend at angles of about <NUM> degrees relative to the upper and lower edges and therefore are aligned with the first set of fibers <NUM>. Therefore the overall shape of the skirt is that of a rhomboid.

The upper edge portion of the skirt <NUM> can be formed with a plurality of projections <NUM> that define an undulated shape that generally follows the shape of the row of struts below the commissure portions <NUM>. In this manner, the upper edge of skirt <NUM> can be tightly secured to the struts with sutures <NUM>. Skirt <NUM> can also be formed with slits <NUM> to facilitate attachment of the skirt to the frame. Slits <NUM> are dimensioned so as to allow an upper edge portion of skirt to be partially wrapped around the struts and reduce stresses in the skirt during the attachment procedure. For example, skirt <NUM> is placed on the inside of frame <NUM> and an upper edge portion of the skirt can be wrapped around the upper surfaces of the struts and secured in place with sutures <NUM>. Wrapping the upper edge portion of the skirt around the struts in this manner provides for a stronger and more durable attachment of the skirt to the frame.

Due to the orientation of the fibers relative to the upper and lower edges, the skirt can undergo greater elongation in the axial direction (i.e., in a direction from the upper edge <NUM> to the lower edge <NUM>). Thus, when the metal frame <NUM> is crimped, the skirt <NUM> can elongate in the axial direction along with the frame and therefore provides a more uniform and predictable crimping profile. Each cell of the metal frame in the illustrated embodiment includes at least four angled struts that rotate towards the axial direction (i.e., the angled struts become more aligned with the length of the frame). The angled struts of each cell function as a mechanism for rotating the fibers of the skirt in the same direction of the struts, allowing the skirt to elongate along the length of the struts. This allows for greater elongation of the skirt and avoids undesirable deformation of the struts when the prosthetic valve is crimped.

In addition, the spacing between the woven fibers or yarns can be increased to facilitate elongation of the skirt in the axial direction. For example, for a PET skirt <NUM> formed from <NUM>-denier yarn, the yarn density can be about <NUM>% to about <NUM>% less than a conventional PET skirt. In some examples, the yarn spacing of the skirt <NUM> can be from about <NUM> yarns per inch (<NUM> inch = <NUM>) to about <NUM> yarns per inch, such about <NUM> yarns per inch, whereas in a conventional PET skirt the yarn spacing can be from about <NUM> yarns per inch to about <NUM> yarns per inch. The oblique edges <NUM>, <NUM> promote uniform and even distribution of the fabric material along inner circumference of the frame during crimping so as to minimize bunching of the fabric to facilitate uniform crimping to the smallest possible diameter. Additionally, cutting diagonal sutures in a vertical manner may leave loose fringes along the cut edges. The oblique edges <NUM>, <NUM> help minimize this from occurring.

The prosthetic valves disclosed herein can also include an outer skirt (not shown) secured to the outside of the frame. The outer skirt assists in forming a good seal between the prosthetic valve and the native annulus to avoid perivalvular leaks. An outer skirt is further described in co-pending Application No. <CIT> (Application No. <CIT>.

The prosthetic valves disclosed herein can be implanted via known techniques. For example, a prosthetic valve can be implanted in a retrograde approach where the prosthetic valve, mounted in a crimped state at the distal end of a delivery apparatus, is introduced into the body via the femoral artery and advanced through the aortic arch to the heart. A prosthetic valve can also be also be implanted via a transapical approach where the prosthetic valve, mounted in a crimped state at the end of a delivery apparatus, is inserted into the heart via a surgical incision in the chest and the apex of the heart.

<FIG> show two possible positions for implanting a prosthetic heart valve of the present disclosure within the native aortic valve. <FIG> shows a first position in which the lobed portions <NUM> of prosthetic valve <NUM> are aligned with the native sinuses in the aortic root to fit the native anatomy. <FIG> shows a second position in which the prosthetic valve <NUM> is rotated <NUM> degrees from the position shown in <FIG>. In the position shown in <FIG>, the commissures <NUM> of the prosthetic valve are generally aligned with the coronary arteries to maximize the space between the openings of the coronary arteries and the outer surface of the prosthetic valve.

<FIG> show a balloon assembly <NUM> of a delivery apparatus, according to one embodiment, that can be used to expand a prosthetic valve to an expanded shape in which the commissure supports <NUM> are bent radially inwardly relative to the sections of the frame extending between the commissure supports. The balloon assembly <NUM> is mounted to the distal end of an elongated shaft <NUM> of the delivery apparatus. The balloon assembly <NUM> in the illustrated embodiment includes a center balloon <NUM> and a plurality of peripheral balloons 204a, 204b surrounding the center balloon. The proximal ends of all of the balloons can be fluidly connected to a central inflation lumen extending through the shaft <NUM>, which allows an inflation fluid to flow into each of the balloons.

The peripheral balloons include a first set of balloons 204a and a second set of relatively shorter balloons 204b that do not extend the entire length of the balloon assembly. Each of the shorter balloons 204b is positioned between two longer balloons 204a. The bare frame <NUM> (without leaflets or skirt) is shown in <FIG> for purposes of illustration. When the prosthetic valve <NUM> is crimped and positioned on the balloon assembly <NUM> for delivery in a patient, the commissure supports <NUM> are aligned with the tapered ends of the shorter balloons 204b. Thus, when the balloons are inflated, the portion of the frame <NUM> below the commissure supports <NUM> expands to a cylindrical configuration, while the commissure portions <NUM> do not fully expand and therefore are titled or bent radially inwardly relative to the struts extending between the commissure portions.

<FIG> is a side elevation view of a prosthetic heart valve <NUM>, according to another embodiment. <FIG> is a top plan view of the prosthetic valve <NUM>. The illustrated prosthetic valve is adapted to be implanted in the native aortic annulus, although in other embodiments it can be adapted to be implanted in the other native annuluses of the heart. The prosthetic valve <NUM> can have three main components: a stent, or frame, <NUM>, a valvular structure <NUM>, and an inner skirt <NUM>. The prosthetic valve <NUM> is configured to be radially compressed to a crimped state for delivery into the body of a patient and radially expandable from the crimped state to an expanded state once positioned at the desired implantation location within the body.

As shown in <FIG>, the frame <NUM> comprises a plurality of longitudinally extending, sinusoidal-shaped or undulating struts <NUM> connected to each other at nodes <NUM> so as to define a plurality of open cells arranged in rows along the longitudinal flow axis of the frame. The frame <NUM> comprises an inflow end portion <NUM> that increases in diameter from a diameter D <NUM> at an inflow end of the frame to a relatively larger diameter D2 at a distance spaced from the inflow end of the frame. An intermediate portion <NUM> of the frame defines a "landing zone" for the frame in that the intermediate portion is positioned within the native annulus when the prosthetic valve is deployed. The intermediate portion initially decreases in diameter from diameter D2 to a relatively smaller diameter D3 at about a middle section <NUM> of the intermediate portion and then increases in diameter to a diameter D4 proximate the outflow end of the frame. The middle section <NUM> of the intermediate portion can be a cylindrical shape having a relatively constant diameter D3 along the length of the frame between the section that decreases in diameter from diameter D2 to diameter D3 and the section that increases in diameter from D3 to diameter D4. An outflow portion <NUM> of the frame decreases in diameter from diameter D4 at the outflow end of the intermediate portion to a diameter D5 at an outflow end of the frame. In particular embodiments, D2 is equal to D4, D1 is equal to D3, and D5 is less than D1, D2, D3 and D4.

<FIG> shows the frame <NUM> in a flattened, or unrolled, configuration. As best shown in <FIG>, the outflow end portion <NUM> of the frame comprises a plurality of circumferentially spaced, longitudinally extending commissure attachment portions, or posts, <NUM> interspaced between a plurality of frame retaining arms, or posts, <NUM>. The retaining arms <NUM> are used to form a releasable connection between the prosthetic valve <NUM> and corresponding components at the distal end of a delivery catheter to retain the prosthetic valve at the end of the delivery catheter until the prosthetic valve is properly positioned at its target deployment location within the body. The retaining arms <NUM> typically are used when the frame is a self-expanding frame since there is no balloon to retain the prosthetic valve in place during deployment. If the frame is a plastically-expandable frame that is deployed with a balloon or similar expansion device, the retaining arms typically are not provided. Details of a delivery device that is configured to retain a self-expandable prosthetic valve via retaining arms <NUM> is disclosed in <CIT>. In the illustrated embodiment, the frame <NUM> has six such retaining arms <NUM>, although a greater or fewer number of retaining arms may be used. Also, the frame <NUM> in the illustrated embodiment has three commissure attachment portions <NUM> corresponding to the three commissures formed by the leaflets <NUM>. The frame can have a greater or fewer number of commissure attachment portions <NUM> if there are a greater or fewer number of commissures formed by the leaflets <NUM>.

As shown in <FIG>, the retaining arms <NUM> in the illustrated configuration extend generally parallel to the flow axis A of the prosthetic valve, or inwardly at a very small angle (e.g., about <NUM>-<NUM> degrees) with respect to the flow axis A, while the commissure attachment portions <NUM> extend inwardly at a much sharper angle with respect the flow axis A. In particular embodiments, for example, the commissure attachment portions <NUM> extend inwardly with respect to the flow axis A at an angle of about <NUM> degrees to about <NUM> degrees, and more particularly, at an angle of about <NUM> degrees to about <NUM> degrees. The upper free ends of the commissure attachment portions <NUM> define the outflow diameter D5 of the prosthetic valve. The retaining arms <NUM> define a diameter D6, which can be greater than the outflow diameter D5.

The shape of the frame <NUM> as depicted in <FIG> has several advantages. The prosthetic valve <NUM> typically is positioned within the sheath of a delivery apparatus such that the inflow end portion <NUM> is adjacent the distal opening of the sheath. The tapered inflow end portion <NUM> can obviate the need for a separate nose cone at the distal end of the delivery apparatus, which typically is used to shield the end of the frame from contacting surrounding tissue during delivery of the prosthetic valve through the patient's vasculature. The tapered inflow end portion <NUM>, which typically is deployed first from the sheath during retrograde delivery to the native aortic valve, can reduce the risk of trauma to native tissue, such as the aortic annulus and the native leaflets, as the prosthetic valve is deployed from the sheath. The tapered inflow end portion also reduces the risk of conduction system obstruction.

The tapered outflow portion <NUM> of the frame reduces the risk of obstructing the coronary ostia when the prosthetic valve is implanted in the native aortic annulus. When implanted, the outflow portion is spaced inwardly of the aortic root, allowing blood to flow into the coronary arteries. Moreover, the tapered outflow portion can reduce the risk that calcified native leaflets will be pushed against and block the coronary ostia. Also, when deploying, positioning, or retrieving the prosthetic valve and during normal operation of the implanted prosthetic valve, the tapered outflow portion reduces the risk of interaction with the sinotubular junction.

The shape of the intermediate section <NUM> facilitates positioning of the prosthetic valve by providing a relative large middle section <NUM> for positioning within the native annulus. The enlarged inflow and outflow sections <NUM>, <NUM>, respectively, of the intermediate section <NUM> (at D2 and D4) assist in centering the prosthetic valve lengthwise with respect to the native annulus. The enlarged inflow and outflow sections <NUM>, <NUM> also enhance anchoring of the prosthetic valve by engaging the lower and upper portions of the native valve. Thus, the inflow section <NUM> can engage the ventricular side of the native aortic valve and inhibit implant migration toward the aorta, while the outflow section <NUM> can engage the aortic side of the native aortic valve and inhibit implant migration toward the left ventricle. In this manner, the intermediate portion <NUM> can provide stable fixation for the prosthetic valve even for a non-calcified aortic root. Moreover, contact between the enlarged inflow section <NUM> and adjacent tissue and between the enlarged outflow section <NUM> and adjacent tissue can enhance perivalvular sealing between the skirt <NUM> and the native annulus.

Another advantage of the frame design is that is facilitates re-sheathing and/or repositioning of the prosthetic valve. As noted above, the retaining arms <NUM> of the frame can be secured to connection devices on the distal end of the delivery apparatus when the prosthetic valve is being implanted in the body. Under ideal circumstances, the prosthetic valve is implanted by deploying the prosthetic valve from the sheath of the delivery apparatus at or near the deployment location, adjusting the position of the prosthetic valve (if necessary) and releasing the connection between the retaining arms <NUM> and the delivery apparatus. In some cases, it may be necessary or desirable to fully or partially re-sheath the prosthetic valve (retract the prosthetic valve back into the sheath) after it is deployed in order to reposition the prosthetic valve or to remove it completely from the body. Because the commissure attachment portions <NUM> extend radially inwardly relative to the retaining arms <NUM>, the distal ends of the commissure attachment portions <NUM> can be retained in a compressed state having a compressed diameter smaller than the inner diameter of the sheath of the delivery apparatus. Thus, even if the prosthetic valve is fully deployed from the delivery sheath, the commissure attachment portions <NUM> can be retracted back into the sheath, followed by the remaining portion of the prosthetic valve for repositioning the prosthetic valve or withdrawing it from the body.

<FIG> is a top plan view of the prosthetic valve <NUM> with the skirt <NUM> removed for purposes of illustration. <FIG> also shows the leaflets <NUM> in an open position under systolic pressure, allowing blood to flow through the prosthetic valve. As can be seen, the cantilevered and angled commissure attachment portions <NUM> support respective commissures <NUM> of the valvular structure inwardly toward the central flow axis A and away from adjacent portions of the frame <NUM> to avoid contact between the moveable portions of the leaflets and the frame. The angled commissure attachment portions <NUM> also reduce the distance between the commissures, enabling a more efficient leaflet design, as further described below. As noted above, the angle of the commissure attachment portions <NUM> can be varied depending on the particular application. <FIG> shows an embodiment where the commissure attachment portions <NUM> extend inwardly at about a <NUM>-degree angle relative to the retaining arms <NUM>. <FIG> shows an embodiment where the commissure attachment portions <NUM> extend inwardly at about a <NUM>-degree angle relative to the retaining arms <NUM>.

<FIG> shows a leaflet <NUM> of the valvular structure <NUM>. The leaflet <NUM> in the illustrated embodiment comprises a substantially V-shaped or scalloped lower edge <NUM> extending between the lower edges of tabs <NUM> and a substantially V-shaped or scalloped upper edge <NUM> extending between the upper edges of the tabs <NUM>. By reducing the distance between the commissures <NUM>, the width W of the leaflet <NUM> (measured between opposing side edges at any location along the height H of the leaflet) can be minimized and the upper edge <NUM> can have a relatively pronounced concavity, which reduces the overall size of the leaflet compared to a known leaflet <NUM> (<FIG>) for the same size prosthetic valve. The smaller, more efficient leaflet design occupies much less space inside the crimped prosthetic valve and therefore allows the prosthetic valve to be crimped to a smaller diameter for delivery.

Because the commissure attachment portions <NUM> are cantilevered relative to the frame, they can deflect slightly during operation of the prosthetic valve, which improves valve operation and durability. In particular, when the leaflets <NUM> close under diastolic pressure, the commissure attachment portions <NUM> can deflect inwardly to relieve stress and strain on the leaflets (especially the commissure attachment points of the leaflet tabs <NUM>), which improves long term durability of the leaflets. Also, when the leaflets open under systolic pressure (as depicted in <FIG>), the upper edges <NUM> of the leaflets are retained at a position spaced from the inner surface of the frame to prevent abrasion and increase leaflet durability. Providing an enlarged diameter D4 (<FIG>) within the outflow portion <NUM> of the frame also assists in creating a gap between the inner surface of the frame and the leaflets when the leaflets are in the open position.

The cantilevered commissure attachment portions <NUM> can also help avoid "pinwheeling" of the leaflets. "Pinwheeling" is a phenomenon characterized by twisting of the upper edges of the leaflets when the leaflets close under diastolic pressure. The twisting motion results in increased flexion and stress on the leaflets, which can adversely effect the durability of the leaflets. The flexible commissure attachment portions <NUM> can absorb some of the closing forces on the leaflets and allow the leaflets to close more gently under diastolic pressure, thereby preventing or at least minimizing the pinwheeling effect.

The concave upper edges <NUM> of the leaflets and the cantilevered commissure attachment portions <NUM> can also help avoid "reverse bending" of the leaflets. "Reverse bending" of leaflets refers to irregular folds or bends that can occur when the leaflets open under systolic pressure. The stresses generated on the leaflet tissue by such bending or folding of the leaflets can lead to fatigue failure of the leaflet. When the leaflets <NUM> open under systolic pressure, the commissure attachment portions <NUM> are deflect slightly outwardly away from the flow axis A, taking up or reducing slack along the upper edges <NUM> of the leaflets. This inhibits the formation of irregular folds or bends in the leaflets, allowing the leaflets mimic the shape of the native aortic leaflets in the open position. The concave upper edges of the leaflets also reduces the amount of slack between the commissures to further ensure the leaflets can be achieve a more natural shape without irregular folds or bends when opened under systolic pressure.

<FIG> is an enlarged view of a commissure attachment portion <NUM>. The commissure attachment portion <NUM> comprises at least two cantilevered struts that are configured to provide a clamping or pinching force against a pair of leaflet tabs <NUM> to assist in securing the leaflet tabs to the frame. In the illustrated configuration, each attachment portion <NUM> comprises two cantilevered inner struts <NUM> and two cantilevered outer struts <NUM> extending from a common base <NUM>. The two inner struts <NUM> are spaced apart from each other to define a leaflet-receiving gap therebetween. Similarly, each outer strut <NUM> is spaced apart from a corresponding adjacent inner strut <NUM> to define a respective leaflet-receiving gap therebetween. The inner and outer struts <NUM>, <NUM> are used to secure the commissures <NUM> of the leaflets. Each outer strut <NUM> can be formed with a small recess or notch <NUM> that can be used to retain a suture that extends around the attachment portion <NUM>, as further described below.

Referring now to <FIG>, a method for securing the commissures <NUM> to the commissure attachment portion <NUM> will now be described. Each commissure attachment portion <NUM> supports a pair of adjacent tab portions <NUM> of two leaflets <NUM> on the inner and outer struts <NUM>, <NUM>. As best shown in <FIG>, a pair of tab portions 334a and 334b extend through the gap between the inner struts <NUM>. On the radial outer side of the commissure attachment portion, the tab portions <NUM> are folded away from each other, forming a first fold 346a and a second fold 346b. The first fold 346a extends through a respective gap between an inner strut <NUM> and an adjacent outer strut <NUM>. The second fold 346b extends through a respective gap between the inner strut <NUM> and the adjacent outer strut <NUM>. Tab portion 334a can then be folded again to form a fold 348a that lies against the outside of fold 346a. Likewise, tab portion 334b can be folded again to form a fold 348b that lies against the outside of fold 346b. Fold 348a can be secured to fold 346a by a suture 350a that extends along the length of the folds. Likewise, fold 348b can be secured to fold 346b by a suture 350b that extends along the length of the folds.

Each pair of the tab portions <NUM> can be reinforced with a reinforcement portion <NUM>, which can be cut or otherwise formed from a sheet of strong, flexible material, such as PET. The reinforcement portion <NUM> reinforces the connection of the leaflet tab portions to the frame and protects the portions of the leaflets on the outside of the frame from contacting the delivery sheath. The reinforcement portions <NUM> can be three separate pieces of material mounted to the commissure attachment portions <NUM>. Alternatively, the reinforcement portions <NUM> can be integral upper extensions of the skirt <NUM> (i.e., the skirt <NUM> and the reinforcement portions <NUM> can be a single piece of material).

<FIG> shows a commissure <NUM> before a reinforcement portion <NUM> is placed on and secured to the attachment portion <NUM>. <FIG> shows a reinforcement portion <NUM> in an unfolded configuration prior to being placed on and secured to an attachment portion <NUM>. The reinforcement portion <NUM> can be folded partially around a pair of tab portions <NUM> to form a rear portion <NUM> (<FIG>) that extends along the radial outside surface of the commissure attachment portion <NUM>. Extending from the longitudinal edges of the rear portion <NUM> are side flaps 356a, 356b. As best shown in <FIG>, side flap 356a extends between leaflet fold 346a and an adjacent outer strut <NUM> and side flap 356b extends between leaflet fold 346b and an adjacent outer strut <NUM>. As best shown in <FIG>, a top flap <NUM> extends from the upper edge of the rear portion <NUM> and covers the top of the commissure attachment portion <NUM>. A front flap <NUM> extends downwardly from the front edge of the top flap and covers the portion of the commissure attachment portion <NUM> above the leaflets. Two upper side flaps <NUM> extend downwardly from the upper side edges of the top flap <NUM> and cover the opposite sides of the commissure attachment portion <NUM> above the leaflets. As best shown in <FIG>, each of the side flaps <NUM> can be a double layer comprising an inner fold and an outer fold.

The leaflet tab portions <NUM> and the reinforcement portion <NUM> can be tightly secured to the inner and outer struts <NUM>, <NUM> by a suture loop <NUM> (<FIG>) that is tightened around the upper end portions of the struts <NUM>, <NUM>. Because the struts <NUM>, <NUM> are cantilevered themselves and unattached to each other at their upper ends, tightening the suture loop <NUM> draws the struts <NUM>, <NUM> inwardly toward the longitudinal centerline of the commissure attachment portions <NUM> (the line equidistant from the inner struts <NUM>), thereby clamping the folds of the leaflets and the reinforcement portion between the struts <NUM>, <NUM>. The suture loop <NUM> can be located within the notches <NUM> (<FIG>) of the outer struts <NUM>, which prevent the loop <NUM> from sliding along the length of the struts. Another suture loop <NUM> (<FIG>) can be tightened around the lower end of the commissure attachment portion <NUM> and lower end portion of the reinforcement portion <NUM>.

The lower edge <NUM> of each leaflet <NUM> can be secured to the skirt <NUM> along a suture line <NUM> (<FIG>). The lowermost sections of the lower edges <NUM> of the leaflets (indicated by suture line <NUM>) desirably are aligned with the inflow edge of the frame <NUM>. In this manner, the leaflets <NUM> extend the entire length or substantially the entire length of the frame from the inlet end to the outlet end of the frame. The skirt <NUM> can be secured directly to the frame <NUM> with sutures (not shown), in the same manner that skirt <NUM> (<FIG>) is secured to the frame <NUM> with sutures <NUM>.

The process suturing leaflet commissures to a frame is a time-consuming and tedious process. The struts <NUM>, <NUM> of the commissure attachment portions are advantageous in that they provide a robust attachment for the leaflet tab portions <NUM> while significantly minimizing the extent of suturing required to secure the leaflet commissures to the frame compared to known techniques. In particular embodiments, for example, only two suture loops <NUM>, <NUM> are used to secure a reinforcement portion <NUM> to a commissure attachment portion <NUM> and to a pair of leaflet tab portions <NUM>, and other than sutures 350a, 350b, no further stitching is required to secure together multiple folds of the leaflet to each other or to the folds of the reinforcement portion <NUM>.

Another important advantage provided by the commissure attachment portions is that they minimize the amount of leaflet material positioned on the outside of the frame. This reduces friction between the outside of the prosthetic valve and the deliver sheath, such as when the prosthetic valve is deployed from the sheath. Moreover, if the prosthetic valve is retracted back into the sheath after its initial deployment, the prosthetic valve can slide more easily back into the sheath while minimizing the risk of damage to the leaflet material on the outside of the frame that may occur from contact with the distal end of the sheath.

<FIG> shows another embodiment of a frame <NUM> that can be used in the prosthetic valve <NUM>. Frame <NUM> is similar to frame <NUM> (<FIG>), except for the number of cells bridging the intermediate portion <NUM> and the outflow portion <NUM>. Referring to <FIG>, except for the uppermost row of cells formed by the retaining arms <NUM>, each row <NUM> of cells of the frame includes twelve cells <NUM>. Referring to <FIG>, the uppermost row <NUM> of cells bridging the intermediate portion <NUM> and the outflow portion <NUM> includes six cells <NUM>, which reduces the amount of metal in that portion of the frame. The uppermost row <NUM> of cells circumscribes the widest portion of the leaflets (except for the tab portions <NUM>) and therefore corresponds to the volume occupied by the bulk of the leaflets when the prosthetic valve is radially crimped. Therefore, the removal of metal from the frame, and in particular from the portion of the frame circumscribing the widest portion of the leaflets, allows for a smaller crimped diameter for the prosthetic valve.

<FIG> illustrates an embodiment of a prosthetic valve <NUM>, which is described in detail in <CIT>. The prosthetic valve <NUM> can have three main components: a stent, or frame, <NUM>, a valvular structure <NUM>, and an inner skirt <NUM>. The prosthetic valve <NUM> is configured to be radially compressed to a crimped state for delivery into the body of a patient and radially expandable from the crimped state to an expanded state once positioned at the desired implantation location within the body. The valvular structure <NUM> can comprise three leaflets <NUM>, collectively forming a leaflet structure, which can be arranged to collapse in a tricuspid arrangement, as shown.

<FIG> is an enlarged view of a section of the prosthetic valve <NUM> showing the connection of a commissure <NUM> of two adjacent leaflets <NUM> to the frame. As shown, the commissure <NUM> is formed by securing a pair of leaflet tab portions <NUM> to each other and to a commissure attachment post <NUM> of the frame <NUM> with sutures <NUM>. The lower edges of the leaflets <NUM> can be sutured to the skirt <NUM> along a suture line <NUM>, and the skirt <NUM> can be secured to the frame <NUM> with sutures <NUM>.

<FIG> shows a stent, or frame, <NUM> according to another embodiment that can be used in the prosthetic valve <NUM> of <FIG> and <FIG>. In particular embodiments, the frame <NUM> is a plastically-expandable frame (i.e., is expanded with a balloon or equivalent mechanism) and is configured to undergo post-deployment shaping after being deployed in a patient's body. In particular, the frame <NUM> in the illustrated configuration is configured to be deployed into a generally cylindrical configuration using a conventional cylindrical balloon, and after deflating and removing the balloon, the commissure attachment portions can bend inwardly to support the commissures of the leaflets at locations closer to the central flow axis of the prosthetic valve. In particular embodiments, a prosthetic valve can comprise the frame <NUM> and the leaflet structure <NUM> comprising leaflets <NUM> of the prosthetic valve <NUM>.

<FIG> shows the frame <NUM> in a radially expanded state after being expanded by an inflatable balloon of a balloon catheter. The balloon can be a conventional balloon that assumes a generally cylindrical shape when inflated. Hence, as depicted in <FIG>, the frame <NUM> can assume a generally cylindrical shape when expanded by the balloon. The frame <NUM> in the illustrated configuration comprises a plurality of commissure attachment posts, or struts, <NUM> (three in the illustrated embodiment), a first row of struts <NUM> at the inflow end of the frame, and a second row of struts <NUM> and a third row of struts <NUM> at the outflow end of the frame. A plurality of longitudinal struts <NUM> extend between the apices of the first row of struts <NUM> and nodes <NUM> adjoining adjacent cells formed by struts <NUM> and <NUM>.

The frame <NUM> is configured to permit inward titling or displacement of the upper portions <NUM> of the commissure attachment posts <NUM> when they are first subjected to a closing force of the leaflets under diastolic pressure and then remain in the tilted position. To such ends, struts 606a and 608a that are connected directly to the commissure attachment posts <NUM> can be weakened relative to the other struts by reducing or thinning the cross-sectional profile of the struts 606a, 608a, such as by reducing the thickness and/or width of the struts 606a, 608a, and by providing one or more curves or bends in the struts 606a, 608a. The curves or bends in the struts 606a, 608a provide slack in those struts to permit the commissure attachment posts <NUM> to flex inwardly relative to longitudinal struts <NUM>.

When the prosthetic valve is first deployed within the native aortic valve (or another native heart valve) by inflating a balloon, the frame <NUM> is expanded to the expanded shape shown in <FIG>. Upon deflation and removal of the balloon, diastolic pressure causes the leaflets (e.g., leaflets <NUM>) to close, and the closing force of the leaflets draws the upper portions <NUM> of the commissure attachment posts <NUM> to bend or tilt inwardly to the positions shown in <FIG>. As the posts <NUM> are drawn inwardly, the struts 606a, 608a are straightened and limit further bending of the posts <NUM>. The struts 606a, 608a in their straightened or nearly straightened configuration exhibit sufficient rigidity to retain the posts <NUM> in their titled position under systolic pressure. Thus, after the initial prosthetic valve closing, the posts <NUM> remain their titled position supporting the commissures (e.g., commissures <NUM>) closer to the longitudinal flow axis of the prosthetic valve. Accordingly, a plastically-expandable prosthetic valve incorporating the frame <NUM> can achieve an overall shape similar to that shown in <FIG> without a specially shaped balloon assembly. The inwardly canted posts <NUM> support the moveable portions of the leaflets away from the inner surface of the frame <NUM> when the leaflets are in the open position, thereby protecting the leaflets against abrasion caused by contact between the leaflets and the frame, as previously discussed.

If desired, the struts 604a of the first row that are connected directly to the posts <NUM> can have a configuration similar to posts 606a, 608a. Weakening the struts 604a connected to the lower ends of posts <NUM> can facilitate displacement of the posts <NUM> by allowing for slight outward deflection of the lower ends of the posts <NUM>. In addition, the posts <NUM> can be weakened at one or more selected locations to facilitate displacement of the posts. As shown in <FIG>, for example, each post <NUM> can have a slit, or recessed portion, <NUM> formed in the inner surface of the post at a location just above the first row of struts <NUM>. The recessed portions <NUM> weakens the posts <NUM> and function as a pivot for the posts, allowing the posts to more easily bend at the recessed portions <NUM> when subjected to the force of the initial closing of the leaflets. In addition to or in lieu of the recessed portions <NUM>, the posts <NUM> can be weakened by reducing the width and/or the thickness of the posts at selected locations to facilitate displacement of the posts.

A modification of the frame <NUM> is shown in <FIG>. In this embodiment of the frame <NUM>, tether or wires <NUM> can be used to limit the extent of inward displacement of the upper end portions of the posts. For example, each post <NUM> can be connected to a pair of wires <NUM>, each having one end secured to an apex <NUM> of the third row of struts and another end secured to the upper end portion <NUM> of the post <NUM>. When the frame is initially expanded and before subjected to the closing force of the leaflets, there is sufficient slack in the wires <NUM> to allow the posts <NUM> to bend inwardly. The length of the wires <NUM> is selected to allow the posts <NUM> to bend or tilt inwardly a limited amount when subjected to the force of the initial closing of the leaflets. Upon initial closing of the leaflets, the wires <NUM> are pulled taught and limit the extent to which the upper end portions of the posts <NUM> can be pulled inwardly by the force of the leaflets.

Claim 1:
A radially collapsible and balloon-expandable frame (<NUM>) for a prosthetic valve (<NUM>), wherein the frame (<NUM>), when viewed in a flattened state thereof, comprises a plurality of struts (<NUM>), the struts (<NUM>) extending longitudinally, being sinusoidal-shaped or undulating, and connecting to each other at nodes (<NUM>) so as to define a plurality of open cells (<NUM>) arranged in plural rows along the longitudinal flow axis of the frame (<NUM>);
wherein the plural rows consist of one inflow row of cells, one outflow row of cells, and one or two intermediate rows of cells between the inflow and outflow rows of cells;
wherein the outflow row includes six cells (<NUM>), and the inflow row and each intermediate row include twelve cells (<NUM>) each,
wherein three circumferentially spaced, longitudinally extending commissure attachment posts (<NUM>) are interspaced between a plurality of frame apices, and
wherein the frame (<NUM>) is suitable for being balloon-expanded in a shape defined by:
an inflow end portion (<NUM>) of the frame (<NUM>) increasing in diameter from a diameter D1 at an inflow end of the frame (<NUM>) to a relatively larger diameter D2 at a distance spaced from the inflow end of the frame (<NUM>),
an intermediate portion (<NUM>) defining a landing zone for positioning the intermediate portion (<NUM>) within the native annulus when the prosthetic valve (<NUM>) is deployed, the intermediate portion (<NUM>) initially decreasing in diameter from the diameter D2 to a relatively smaller diameter D3 at a middle section (<NUM>) of the intermediate portion (<NUM>) and then increasing in diameter to a diameter D4 proximate an outflow end of the frame (<NUM>),
an outflow portion (<NUM>) of the frame (<NUM>) decreasing in diameter from the diameter D4 at an outflow end of the intermediate portion (<NUM>) to a diameter D5 at the outflow end of the frame (<NUM>), the diameter D5 being defined by upper free ends of the commissure attachment posts (<NUM>), and
the commissure attachment posts (<NUM>) extending inwardly at an angle of about <NUM> degrees to about <NUM> degrees with respect the flow axis A.