Patent Description:
Heart valve disease is a significant cause of morbidity and mortality, resulting from a number of ailments including rheumatic fever and birth defects. The natural heart valves are identified as the aortic, mitral (or bicuspid), tricuspid and pulmonary valves, and each has leaflets to control the directional flow of blood through the heart. Worldwide, approximately <NUM>,<NUM> heart valve replacement surgeries are performed annually, and about one-half of these patients receive bioprosthetic heart valve replacements, which utilize biologically derived tissues for flexible fluid-occluding leaflets.

Heart valve prostheses are either of the mechanical type that originally used a ball and cage and more recently a pivoting mechanical closure, or a tissue type or "bioprosthetic" valve typically constructed with natural-tissue valve leaflets. The most successful bioprosthetic materials for flexible leaflets are whole porcine valves and separate leaflets made from bovine pericardium stitched together to form a tri-leaflet valve. However, flexible leaflets formed of polymeric, fiber-reinforced, and other synthetic materials have also been proposed. The most common flexible leaflet valve construction includes three leaflets mounted to a peripheral support structure and commissure posts that project in a downstream or outflow direction. The leaflets have free edges between the commissure posts that meet or coapt in the middle of the flowstream to permit one-way flow. A suture-permeable sewing ring around the inflow end typically provides a platform for anchoring sutures.

Prosthetic valves typically have a delivery holder centrally located and sutured thereto, and an elongated delivery handle coupled to the holder for manipulating the valve assembly during implant. For the standard delivery approaches, the holder is attached to the inflow side such as the sewing ring for mitral valves and to the outflow side such as the stent cusps or outflow commissure tips for aortic valves.

When placing a flexible leaflet prosthetic valve in the mitral or tricuspid position, the commissure posts are on the leading or blind side of the valve during delivery and implant, and the surgeon uses the holder and an attached handle to slide (parachute) the valve down an array of sutures that have been pre-installed around the mitral annulus and then passed through the valve sewing ring. The mitral position is such that the outflow end with commissure posts is the leading end as it advances toward the left ventricle during implantation, and thus the holder is attached to the inflow (i.e., trailing) end of the valve. The difficulty of the delivery task is compounded by the small access pathway into the left atrium. Suture looping sometimes occurs when one or more of the sutures in the parachute array inadvertently wraps around the inside of one or more of the commissure post tips. If this occurs, the looped suture(s) may slow down the implant procedure, damage one of the tissue leaflets when tightly tied down, or interfere with valve operation and prevent maximum coaptation of the valve leaflets, resulting in a deficiency in the prosthetic mitral valve. These issued can be resolved inter-operatively if the surgeon is aware of the suture looping, but because the loops occur on the blind side of a mitral or tricuspid valve the surgeon might not be aware of a suture loop. If the surgeon does not eliminate the suture loop and leaves a valve implanted with a suture looped over the leaflet it is very likely to result in leaflet tearing forcing what can be an emergency surgery. If after tearing initiates, it is not correctly diagnosed and treated the consequences can be fatal for the valve recipient.

Existing mitral valve holders on the market attempt to mitigate the potential for suture looping of the commissure posts during implantation by moving the posts toward the central axis of the valve (post constriction). For example, <CIT>, provides a holder having a mechanism that constricts the commissure posts inwardly just prior to implantation. The Carpentier device provides an elongate handle to both hold the valve/valve holder combination during implantation, as well as to cause the commissure posts to constrict inwardly. More recently, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT> disclose heart valve holder systems that resist suture looping.

Bioprosthetic heart valves configured for implanting in the aortic or pulmonic position also can benefit from constriction of the commissure posts. That is, although the holder attaches to the outflow side of the valve, the lower radial profile of the commissure posts eases implantation, such as through an aortotomy.

Bioprosthetic heart valves are conventionally packaged in jars filled with preserving solution for shipping and storage prior to use in the operating theater. Glutaraldehyde is widely used as a storage solution due to its sterilant properties. Because glutaraldehyde is a fixative, or cross-linking agent, and the fixing process is ongoing, bioprosthetic valves are stored in the jars with their leaflets in the closed or coapting position and the commissure posts relaxed, not constricted. This is to ensure that the leaflets fix in the shape they are supposed to have when closed. Otherwise the leaflets may assume a distorted shape which could detrimentally affect functioning, such as regurgitation upon implant. As a consequence, prior art devices that constrict the commissures are actuated in the operating room, just prior to implant of the valve. Various designs are available, each of which require an affirmative action which creates a risk that the operating room staff will not completely constrict the commissure posts, possibly leading to suture looping. To compound the problem, the devices sometimes require several precise steps, which can be confusing in the pressured environment of a heart surgery with the patient on bypass.

Despite a number of advances, there is still a need in the art for a holder and associated packaging for tissue-type prosthetic mitral valves that helps prevent suture looping and is more intuitive to use.

<CIT> describes a multi-function valve exchange apparatus including an alignment tool for locating tools of the multi-function valve exchange apparatus proximate to an installed cardiovascular valve assembly comprised of a base member and an exchangeable valve member detachably coupled thereto; a stabilizer tool for grabbing the base member and preventing the base member from moving during a procedure for exchanging the existing valve member with a new valve member; removal and collapsing tools for uncoupling and removing the existing valve member; and an installation tool for installing a new exchangeable valve member having a new leaflet set. A method for exchanging a valve member uses the multi-function valve exchange apparatus to facilitate removal of the existing exchangeable valve member and installation of the new exchangeable valve member.

<CIT> describes tools for the removal and installation of exchangeable cardiovascular valves. The tools facilitates exchange of a cardiovascular valve member mounted in the aortic position (retrograde exchange) or the mitral position (transapical exchange).

The present invention relates to a valve holder, its use, a prosthetic heart valve assembly and a method of packaging a prosthetic heart valve as defined in appended claims <NUM>, <NUM>, <NUM> and <NUM>, respectively.

The present application provides a holder and associated packaging system for prosthetic heart valves that is more intuitive to use and pre-constricts and/or pre-shields the commissure posts of the valve to prevent suture looping and ease implantation. Pre-constriction and pre-shielding mean at the time of manufacture, so that the valves are stored for at least <NUM> hours with the commissure posts constricted and/or shielded. The valve may be bioprosthetic and stored dry to avoid continued cross-linking of the leaflets. Capping the glutaraldehyde terminates the cross-linking process by consuming all of the amines eliminating cross-linking sites for the aldehydes. In certain embodiments, the holders have solid legs that directly contact, constrict and hold the commissure posts without the use of sutures in tension that might creep over the time in storage.

For an aortic valve, the holder may have a solid hub and legs on the outflow end of the valve that retain the commissure posts inward. For a mitral valve, the holder may have a base in contact with the inflow end and a shaft portion that projects through the valve leaflets and cooperates with movable legs on the outflow end of the valve in contact with the commissure posts. Disclosed methods include constricting the valve commissure posts and then packaging the valve in a sterile container.

Embodiments of a valve holder for a prosthetic heart valve can be employed for shielding the tips of the commissure posts during implantation of the prosthetic heart valve at a native heart valve annulus to prevent suture looping and ease implantation without necessarily pulling or otherwise constricting the commissure posts radially inward. The holder can have a base in contact with an inflow end of a prosthetic valve and a shaft portion that projects through the valve leaflets and cooperates with flexible members on an outflow end of the prosthetic valve to shield the tips of commissure posts. Disclosed methods include shielding the valve commissure posts and then packaging the valve in a sterile container along with the valve holder.

The valve holder for a prosthetic heart valve of the present invention comprises a plurality of angularly spaced, leg members configured to extend through a prosthetic valve in an outflow direction. The prosthetic heart valve has an inflow end, an outflow end, and plural commissure posts ending in tips projecting in the outflow direction. The leg members have distal end shielding portions and are moveable between a radially outward position and a radially inward position, wherein when the leg members are in the radially outward position, the distal end portions extend over and shield the tips of the commissure posts of the prosthetic valve and wherein when the leg members are in the radially inward position, the distal end portions are spaced radially inward of the commissure tips and can be withdrawn through the prosthetic valve in a direction toward the inflow end. The leg members comprises respective proximal portions connected to a base ring configured to abut the inflow end of the prosthetic valve.

In another aspect of the invention, a prosthetic heart valve assembly comprise a prosthetic heart valve and the valve holder of the invention. The prosthetic heart valve has an inflow end, an outflow end, and plural commissure posts ending in tips projecting in an outflow direction. The valve holder comprises an inner body member and an outer shielding member. The outer shielding member comprises the plurality of angularly spaced, flexible leg members, each having the proximal portion extending through the prosthetic valve and the distal end portion disposed over a tip of a corresponding commissure post. The inner body member comprises a shaft extending through the leg members and retaining the leg members in the radially outward position in which the distal end portions cover the tips of the commissure posts. Removal of the shaft from the leg members in a direction toward the inflow end of the prosthetic valve allows the leg members to flex to the radially inward position away from the tips of the commissure posts to allow the leg members to be withdrawn through the prosthetic valve in a direction toward the inflow end.

In another representative embodiment (not in accordance with the invention), a method of implanting a prosthetic heart valve comprises providing a prosthetic heart valve assembly comprising a prosthetic heart valve and a valve holder. The prosthetic valve has an inflow end, an outflow end, and plural commissure posts ending in tips projecting in an outflow direction. The valve holder comprises an inner body member and an outer shielding member. The outer shielding member comprises a plurality of angularly spaced, flexible leg members, each having a proximal portion extending through the prosthetic valve and a distal end portion disposed over a tip of a corresponding commissure post. The inner body member comprises a shaft extending through the leg members and retaining the leg members in a radially outward position in which the distal end portions cover the tips of the commissure posts. The method further comprises delivering and securing the prosthetic valve to a native valve annulus in the heart, retracting the inner body member through the inflow end of the prosthetic valve, causing the leg members to flex radially inwardly away from the commissure posts, and then retracting the shielding member through the inflow end of the prosthetic valve.

In another aspect of the invention, a method of packaging a prosthetic heart valve comprises providing a prosthetic heart valve having an inflow end, an outflow end, and plural commissure posts ending in tips projecting in an outflow direction, and providing a shielding member comprising a plurality of flexible leg members, each having a distal end shielding portion. The leg members are inserted into the inflow end of the prosthetic valve until the distal end shielding portions are distal to the tips of the commissure posts and the leg members are then bent or deflected radially outward such that the distal end shielding portions cover the tips of the commissure posts. The prosthetic heart valve and the shielding member can then be packaged for storage and/or shipping.

Features and advantages of the present invention will become appreciated as the same become better understood with reference to the specification, claims, and appended drawings.

The present invention provides improved systems and methods for packaging and storing prosthetic heart valves to reduce complications during valve delivery. The prosthetic heart valves can include flexible, typically bioprosthetic, leaflets that coapt in the flowstream and are supported by a surrounding stent structure including upstanding commissure posts. As is well known in the art, the peripheral edges of the leaflets, either separate or within a whole xenograft valve, are secured to the surrounding stent structure including the upstanding commissure posts which are cantilevered in the outflow direction. The commissure posts are capable of flexing to a certain degree to accommodate the forces of fluid dynamics after implant. The flexing of the commissure posts helps the flexible leaflets both close and open at the appropriate time, and mimics the action of the natural commissures of the respective heart valve annulus. However, because the commissure posts extend axially in the outflow direction, they present problems during delivery of the valve to the target implantation site.

The present application describes systems and methods for pre-constricting the upstanding commissure posts so that they flex radially inward and present a smaller radial profile during delivery of the valve by the surgeon to the target implantation site. The present application also describes systems and methods for pre-shielding the tips of the upstanding commissure posts during delivery without necessarily constricting the commissure posts. The prosthetic heart valve assembly can include a holder and a plurality of flexible members extending through the prosthetic valve and having distal end portions extending over and shielding the tips of the commissure posts. The terms "pre-constricting" and "pre-constricted" refer to constriction of the commissure posts prior to the operating room technicians opening the sterile packaging. Likewise, the terms "pre-shielding" and "pre-shielded" refer to shielding of the tips of the commissure posts prior to the operating room technicians opening the sterile packaging. In other words, the prosthetic heart valve and a holder that pre-constricts and/or pre-shields the commissure posts emerges assembled from the packaging, substantially ready for connection to a delivery handle and delivery (after washing off any preserving solution if necessary).

The present application is useful for prosthetic heart valves having commissure posts for any implant site, but is particularly useful for mitral and aortic valves. Furthermore, the present application describes techniques that are particularly useful with dry prosthetic tissue heart valves that do not require liquid containment during storage. However, it is conceivable that the present application could be applicable to "wet" prosthetic heart valves if precautions are taken so that long-term storage of the valves with the commissure posts constricted does not result in distorted leaflets. For example, it is conceivable that synthetic leaflets may someday be successfully used which are not fixed, or cross-linked, and therefore might be stored wet. Alternatively, bioprosthetic leaflets that are fully fixed and are not affected by long-term storage with the commissure posts constricted might benefit from the principles discussed here. In short, the type of prosthetic heart valve or leaflets should not be considered limited unless explicitly stated by an applicable claim.

Now with reference to <FIG>, a prosthetic heart valve <NUM> is shown assembled to a valve holder <NUM> of the present application. The heart valve <NUM> includes an inlet end <NUM> and an outlet end <NUM> separated along a vertical flow axis through the middle of the valve. A cloth-covered frame assembly or support frame <NUM> defines a periphery and flow orifice of the valve and includes commissure posts <NUM> that project generally axially in the outflow direction separated by arcuate cusps <NUM> that curve in the inflow direction. Three flexible leaflets <NUM> couple to the frame <NUM> and extend inward therefrom. The leaflets <NUM> attach along an undulating line that follows the commissure posts <NUM> and cusps <NUM>. A suture-permeable sewing ring <NUM> surrounds the inflow end of the valve <NUM>, and may have a planar peripheral shape as shown or a shape which undulates upward a short distance in the vicinity of the three commissure posts <NUM>.

It should be understood that the terms inflow/inlet and outflow/outlet refer to the direction of blood flow through the valve <NUM>, which is upward in the orientation shown. Additionally, because the illustrated valve <NUM> is for implanting at the mitral annulus, the outlet end <NUM> with the projecting commissure posts <NUM> forms the leading or distal end of the valve during delivery, while the inlet end <NUM> is the trailing or proximal end. Thus, at least in the context of the heart valve <NUM> and holder <NUM> assembly of <FIG>, with regard to directions the terms inlet and proximal are synonymous, as are the terms outlet and distal.

As mentioned above, the prosthetic heart valve <NUM> and other prosthetic heart valves described herein may comprise a number of existing heart valves which have commissure posts <NUM>, and the particular construction of the heart valve aside from having commissure posts is not considered to be an essential part of the present application. However, as will be explained, bioprosthetic heart valves that are stored dry are particularly suitable for integration with the disclosed holders and techniques.

Techniques are known for drying and storing bioprosthetic heart valves without immersing them in a preservative solution. The term "dried" or "dry" bioprosthetic heart valves refers simply to the ability to store those heart valves without the preservative solutions, and the term "dry" should not be considered synonymous with brittle or rigid. Indeed, "dry" bioprosthetic heart valve leaflets may be relatively supple even prior to implant. There are a number of proposed methods for drying bioprosthetic heart valves, and for drying tissue implants in general, and the present application contemplates the use of valves processed by any of these methods. A particularly preferred method of drying bioprosthetic heart valves is disclosed in <CIT> An alternative drying method is disclosed in <CIT> Again, these and other methods for drying bioprosthetic heart valves may be used prior to implementing the storage techniques described herein.

One such strategy is to dehydrate the bioprosthetic tissue in a glycerol/ethanol mixture, sterilize with ethylene oxide, and package the final product "dry. " This process eliminates the potential toxicity and calcification effects of glutaraldehyde as a sterilant and storage solution. There have been several methods proposed to use sugar alcohols (i.e., glycerine), alcohols, and combinations thereof as post-glutaraldehyde processing methods so that the resulting tissue is in a "dry" state rather than a wet state with excess glutaraldehyde. Glycerol-based methods can be used for such storage, such as described in <NPL>). Likewise, <CIT>) describes the storage of bioprosthetic tissue in polyhydric alcohols such as glycerol. In processes where the tissue is dehydrated in an ethanol/glycerol solution, the tissue may be sterilized by ethylene oxide (ETO), gamma irradiation, or electron beam irradiation.

More recently, <CIT> propose solutions for certain detrimental changes within dehydrated tissue that can occur as a result of oxidation. Dove, et al. propose permanent capping of the aldehyde groups in the tissue (reductive amination). Dove, et al. also describe the addition of chemicals (e.g. antioxidants) to the dehydration solution (e.g., ethanol/glycerol) to prevent oxidation of the tissue during sterilization (ethylene oxide, gamma irradiation, electron beam irradiation, etc.) and storage. Tissue processed in accordance with the principles disclosed in Dove, et al. will be termed, "capped tissue," and therefore heart valves which use such tissue will be termed, "capped tissue valves. " Capping the glutaraldehyde terminates the cross-linking process by consuming all of the amines eliminating cross-linking sites for the aldehydes, and it is believed that this in conjunction with removing the tissue valve out of the cross-linking solution (e.g., glutaraldehyde) by storing dry is the most effective way to terminate the cross-linking process.

As seen in <FIG>, the valve holder <NUM> extends through the heart valve <NUM> and has movable legs <NUM> that constrict the commissure posts <NUM> of the heart valve radially inward. More specifically, the valve holder <NUM> comprises a relatively wide base portion <NUM> in contact with the inflow end <NUM> of the heart valve <NUM>, and an axially elongated shaft portion <NUM> extending in the distal direction from the base portion through the heart valve. The shaft portion <NUM> projects along the central axis and distally beyond the leaflets <NUM> of the heart valve. The movable legs <NUM> are arranged to pivot about a top end of the shaft portion <NUM>, as will be described below. There are three movable legs <NUM> corresponding to each of the three valve commissure posts <NUM>.

Each of the movable legs <NUM> has an outer end with a short finger <NUM> that extends down on the outside of a respective commissure post <NUM>. As seen in <FIG>, an inner end of each of the legs <NUM> has a pivot and a lever structure permitting a locking plug <NUM> to actuate the leg <NUM>. More specifically, the upper end of the holder shaft portion <NUM> includes a step <NUM> formed on an inner wall thereof. A fulcrum projection <NUM> on each of the movable legs <NUM> seats on the step <NUM>, while a lever projection <NUM> extends radially inward therefrom. In the illustrated embodiment, the locking plug <NUM> includes a larger diameter lower portion <NUM> and a smaller diameter upper portion <NUM> that creates a ledge <NUM> which receives the lever projections <NUM> of the movable legs <NUM>, as shown in <FIG>. Tethers <NUM> connect the lever projections <NUM> to an upper end of the locking plug <NUM>. A pull wire <NUM> attached to the lower end of the locking plug <NUM> permits the user to displace the locking plug in a proximal direction.

<FIG> illustrate the assembled prosthetic heart valve <NUM> and holder <NUM> as they are provided by the manufacturer in a sterile shipping container or packaging. In this configuration, the valve commissure posts <NUM> are pulled inward and held by the movable legs <NUM> of the holder <NUM>. As seen from the outflow end in <FIG>, the leaflets <NUM> curl up somewhat such that their coapting free edges <NUM> can be seen around the outside of the holder shaft portion <NUM>. After the commissure posts <NUM> are permitted to flex outward into their functional positions, the leaflet free edges <NUM> extend generally radially inward from respective commissure posts toward the central axis in a trefoil configuration (not shown). As explained above, the prosthetic heart valve <NUM> is preferably stored dry with the bioprosthetic tissue used for the leaflets <NUM> treated to enable storage without a liquid preservative. As such, the leaflets <NUM> are fully fixed and are not subject to ongoing cross-linking in the preservative solution. Consequently, even though the leaflets <NUM> are deformed somewhat from their functional shapes during storage, as seen in <FIG>, they will resume their proper functional shapes after removal of the holder <NUM>.

It should be understood that the holder <NUM> with the legs <NUM> constricting the commissure posts <NUM> remains in place during delivery of mitral valve <NUM> until the sewing ring <NUM> seats at the mitral annulus. Constriction of the commissure posts <NUM> is only required during delivery down the array of pre-installed anchoring sutures. The extent to which the commissure posts <NUM> are flexed and held inward from the time of manufacture depends somewhat on the materials used for the cloth-covered support frame <NUM>. That is, the support frame <NUM> (or components therein) has a material stress limit that determines the maximum inward angle at which the commissure posts <NUM> can be flexed and held for extended periods of time. Beyond that stress limit, some material including the metals used to construct heart valves would experience plastic or permanent deformation. Polymer materials when stressed above a point that is characteristic of the material and the storage temperature may experience creep leading to permanent deformation and possibly malfunction after implant. In one embodiment, the commissure posts <NUM> assume a slight inward angle in their relaxed, functional configuration, and are flexed and held inward farther by the holder <NUM> by an additional <NUM>-<NUM>°. For instance, this translates into an additional inward bending distance of between about <NUM>-<NUM> for an average size valve, with the absolute distance being somewhat smaller for smaller valves and vice-versa. Again, this angular deformation depends on the desired radial delivery profile governed by the material stress limits in the support frame <NUM>.

<FIG> are sectional views as in <FIG> showing several steps in detachment and removal of the valve holder <NUM> from the prosthetic heart valve <NUM>, which occurs after seating the heart valve against the target annulus. <FIG> shows proximal displacement of the pull wire <NUM> and locking plug <NUM>. By virtue of the connecting tethers <NUM>, this movement also pulls the lever projections <NUM> on the movable arms <NUM> in a proximal direction. The fulcrum projections <NUM> step <NUM> on the inside of the holder shaft portion <NUM>, and cause the movable arms <NUM> to pivot inwards as shown. This releases the fingers <NUM> of the arms <NUM> from the respective commissure posts <NUM>, which therefore spring outward into their relaxed, functional positions.

<FIG> shows further proximal displacement of the pull wire <NUM> and locking plug <NUM>, which also pulls the movable arms <NUM> together and through a lumen <NUM> of the holder shaft portion <NUM>. The moving parts of the holder <NUM> can therefore be removed completely from the implantation site, possibly through a tubular handle <NUM>. The handle <NUM> connects to a proximal sleeve <NUM> on the holder <NUM>, and may be flexible to enable passage through non-linear access channels.

Finally, <FIG> illustrates removal of the entire holder <NUM> from the prosthetic heart valve <NUM>. In a preferred embodiment, no sutures are used to connect the holder <NUM> to the valve <NUM>, the latter simply being held between the arms <NUM> and the base portion <NUM> of the holder, as in <FIG>. Alternatively, although not shown, connecting sutures may be placed through the outer peripheral edge of the base portion <NUM> and through the valve sewing ring <NUM>. By attaching both ends of each connecting suture to the holder <NUM>, and providing a cut point or well where the suture can be severed in the middle, each of the connecting sutures can be removed with the holder by simply severing the connecting sutures.

<FIG> illustrate alternative locking plugs for use in the exemplary heart valve holder of the present application.

<FIG> illustrate an alternative pre-constricting valve holder <NUM> of the present application assembled with a prosthetic aortic heart valve <NUM>. As mentioned above, during delivery of aortic heart valves the inflow end is the leading or distal end, while the outflow end with its commissure posts is the trailing or proximal end. As such, the valve holder <NUM> couples to the outflow end of the valve <NUM>, or to the tips of the commissure posts <NUM>. As before, the prosthetic valve <NUM> further includes a support frame that defines three upstanding commissure posts <NUM> alternating with three arcuate cusps <NUM>. A cloth covering <NUM> is removed on the right side to expose an exemplary support frame construction. Specifically, the support frame includes a wireform <NUM>, typically metallic, and a stent <NUM>, typically polymeric. Various internal constructions of valve support frames are known in the art, and the illustrated embodiment should not be considered limiting.

The valve holder <NUM> includes a central hub <NUM> having a cavity <NUM> to which a delivery handle (not shown) may be attached. Three legs <NUM> extend outwardly and down at an angle around the outside of and in direct contact with each of the commissure posts <NUM>, thus maintaining the commissure posts inwardly constricted by an angle θ. The angle θ is taken from the line through the commissure posts <NUM> in their relaxed, functional configuration, which is slightly offset from the vertical by an angle α of about <NUM>° as shown. In one embodiment, the commissure posts <NUM> are flexed and held inward by the holder <NUM> by about <NUM>-<NUM>°, which again depends on the desired radial delivery profile governed by the material stress limits in the support frame.

In one embodiment, the legs <NUM> of the holder <NUM> are secured to the tips of the commissure posts <NUM> using sutures or similar expedient which can be easily detached. Alternatively, the legs <NUM> may have retractable features, such as small barbs, that enable them to hold the tips of the commissure posts <NUM> during storage and delivery of the valve to the target implantation site, but enable quick release. Still further bands or ties (not shown) around both the commissure posts <NUM> and legs <NUM> may be used to hold the components together until time to release the valve.

The holder <NUM>, and in particular the outwardly extending legs <NUM>, should be made of a material that will not creep significantly under constant load at the temperatures at which the valve will be stored. Metallic materials including stainless steel, cobalt chromium (CoCr), or titanium would be preferable, but also some polymers are acceptable if the creep resistance will not cause the commissure posts <NUM> to move significantly during storage. For instance, some high-temperature polymers like polyetherimide may be suitable. Additionally, polymers may be reinforced with fibers to prevent creep. Alternatively, the holder can be designed with a high area moment of inertia so the strain is minimized to reduce creep. Creep is a function of material, temperature and the level of stress on the material so thick sections opposing the load from the stent posts could reduce the level of strain.

<FIG> shows an exemplary prosthetic heart valve <NUM> and depicts how a suture can become looped on a commissure post of the valve. The prosthetic heart valve <NUM> comprises an inflow end, an outflow end, leaflets <NUM>, a sewing ring <NUM> at the inflow end, and three commissure posts <NUM> projecting in an outflow direction and ending in tips <NUM>. In the absence of shielding of the tips and/or constriction of the posts <NUM> during delivery of the prosthetic heart valve <NUM>, a suture <NUM> may become hooked on one or more of the commissure tips <NUM> of one of the commissure posts <NUM>, as depicted in <FIG>.

<FIG> show a prosthetic heart valve assembly <NUM> comprising the prosthetic heart valve <NUM> and a valve holder <NUM>, according to another embodiment. As with the embodiment of <FIG>, the prosthetic heart valve <NUM> used in this embodiment and other embodiments described herein can comprise any number of existing prosthetic valves which have commissure posts <NUM>, and the particular construction of the prosthetic valve aside from having commissure posts is not considered to be an essential part of the present application.

The valve holder <NUM> is configured to shield the commissure post tips <NUM> to protect against suture looping during delivery of the prosthetic valve to a native valve annulus. In particular embodiments, the valve holder <NUM> need not constrict the commissure posts <NUM> and instead shield the commissure post tips during valve delivery while the commissure posts can remain in their non-deflected, functional state. The valve holder <NUM> in the illustrated embodiment comprises an inner body member <NUM> and an outer shielding member <NUM> that is disposed around the inner body member in an assembled state. The inner body member <NUM> in the illustrated configuration comprises a base <NUM> and a substantially cylindrical inner shaft <NUM> extending from the base <NUM>. The inner shaft <NUM> can include a resilient tab <NUM> (see <FIG>), the purpose of which is described below. The shielding member <NUM> in the illustrated configuration comprises a base, or base ring <NUM>, a central opening <NUM> defined by the base ring <NUM> (see <FIG>, <FIG>), and a plurality of leg members <NUM> extending from the base ring <NUM>.

As best shown in <FIG>, each leg member <NUM> has a respective proximal base portion <NUM> connected to the base ring <NUM>, a respective distal end portion <NUM>, and a respective intermediate portion <NUM> extending between the base portion and the distal end portion. The shielding member <NUM> desirably has the same number of leg members <NUM> as there are commissure posts <NUM> of the prosthetic valve. Thus, there are three such leg members <NUM> in the illustrated embodiment, although a greater or fewer number of leg members can be provided. The shaft <NUM> can be formed with a plurality of longitudinally extending, circumferentially spaced slots <NUM> configured to at least partially receive respective leg members <NUM> when the assembly is in the assembled state (as shown in <FIG>). The leg members <NUM> desirably are spaced out substantially evenly around the base ring <NUM> to mirror the circumferential spacing of commissure posts <NUM> around the prosthetic valve <NUM>.

The leg members <NUM> are normally biased to assume a radially inward position (<FIG>) and can flex or bend outwardly to a radially outward position (<FIG>). Thus, in the absence of any forces on the leg members <NUM>, they assume the inward position shown in <FIG>; this can be referred to as the relaxed state of the leg members. However, when the shaft <NUM> of the inner body member <NUM> is inserted though the opening <NUM> of the base ring <NUM> and between the leg members <NUM>, the leg members <NUM> are caused to deflect outwardly such that the distal end portions <NUM> are positioned to shield the commissure tips <NUM> (<FIG>), as further described below. Conversely, removal of the shaft <NUM> from the space between the leg members <NUM> allows the leg members to flex or spring back to the radially inward position. In this manner, the leg members <NUM> can be referred to as cantilevered springs.

The distal end portions <NUM> can have a radial thickness that is greater than those of proximal and intermediate portions of the leg members <NUM>. In particular embodiments, the distal end portions <NUM> comprise curved, convex distal end surfaces <NUM> facing away from the commissure tips <NUM> and are adapted to extent over and shield the commissure tips. The intermediate portions <NUM> of the leg members can be relatively thinner than the distal end portions <NUM> and the base portions <NUM> to facilitate deflection of the leg members between the deflected position (<FIG>) and non-deflected position (<FIG>).

To assemble the prosthetic valve <NUM> and the valve holder <NUM> in the manner shown in <FIG>, the shielding member <NUM> is inserted through the prosthetic valve <NUM> (and the leaflets <NUM>) until the distal end portions <NUM> extend beyond the commissure post tips <NUM> and the base ring <NUM> abuts or is adjacent the sewing ring <NUM> of the prosthetic valve. The inner shaft <NUM> of the inner body member <NUM> can then be inserted through the central opening <NUM> and between the leg members <NUM> such that the leg members <NUM> are aligned within respective slots <NUM> on the shaft <NUM>. The shaft <NUM> is pushed through the leg members <NUM> to force the leg members and their distal end portions <NUM> into a radially outward position such that the distal end portions <NUM> extend over and shield the tips <NUM> of the commissure posts <NUM>. As shown in <FIG>, the outer surface of the inner shaft <NUM> can have a resilient tab <NUM> projecting radially outwardly from the outer surface of the shaft. The tab <NUM> is shaped to allow the tab <NUM> to pass underneath the base ring <NUM> when the shaft <NUM> is inserted into the shielding member <NUM> yet engage the base ring <NUM> and prevent separation of the shaft <NUM> and shielding member <NUM> when the shaft is moved in the opposite direction. Thus, as the shaft <NUM> is inserted through the base ring <NUM> and between the leg members <NUM>, the base ring <NUM> can contact the titled or canted outermost surface of the tab <NUM>, which forces the tab to flex inwardly and allow the shaft <NUM> to be fully inserted between the leg members <NUM> (<FIG>). When the tab <NUM> passes the base ring <NUM>, the tab <NUM> flexes or springs back radially outwardly to its relaxed state.

<FIG> is a side perspective view of the prosthetic heart valve assembly <NUM> in an assembled state, showing placement of sutures <NUM> that secure the base <NUM> of the inner body member <NUM> to the base ring <NUM> of the shielding member <NUM>. As shown, the proximal (inflow) surface <NUM> of the base <NUM> can include a plurality of radially extending slots <NUM>. Each of the sutures <NUM> bridges across a respective slot and has two end portions that extend in the outflow direction through the base <NUM> and the base ring <NUM>. The ends of each suture <NUM> passing through the base ring <NUM> can be tied together as shown at <NUM> so as to temporarily secure the inner body member <NUM> to the shielding member <NUM>. The base <NUM> of the inner body member and the base ring <NUM> can have suture holes to allow the sutures <NUM> to pass through those components during assembly. The distal end portions <NUM> of the leg members <NUM> can engage the commissure tips <NUM> such that the prosthetic valve <NUM> is retained in place around the shielding member <NUM>. In alternative embodiments, the same or additional sutures may secure the base <NUM> and/or the base ring <NUM> to the inflow end of the prosthetic valve <NUM> by, for example, threading the sutures through the sewing ring <NUM> of the prosthetic valve <NUM>. The prosthetic valve <NUM> can be introduced into a patient's body and delivered to the desired implantation location (adjacent the mitral valve) in the assembled state shown in <FIG> and <FIG>. In the assembled state, the commissure posts <NUM> of the prosthetic valve <NUM> need not be bent or deflected inwardly and instead can be in a non-deflected, functional position for delivery into the body, as shown.

The proximal surface <NUM> of the base <NUM> of the inner body member <NUM> can include a centrally located threaded bore or opening that can receive the distal end portion of a shaft <NUM> of a delivery tool for manual delivery of the prosthetic heart valve assembly <NUM>. The proximal end of the shaft <NUM> can be connected to a suitable handle for manipulation by a user. In other embodiments, the inner body member <NUM> may have other attaching mechanisms for connecting the shaft of a delivery tool. The present invention is not limited with respect to the type of delivery tool, handle or related apparatus or with respect to the type of connection to the delivery tool. Once the user has attached the delivery tool, the prosthetic heart valve assembly <NUM> may be delivered and secured to a native valve annulus in the heart such as the mitral valve annulus.

<FIG> shows the prosthetic valve <NUM> and the holder <NUM> as they are provided by the manufacturer in a sterile shipping container or package. The shaft of a delivery tool can be pre-attached to the holder <NUM> and packaged together with the prosthetic valve and the holder. In other embodiments, the delivery tool shaft can be packaged separately and can be mounted to the valve holder by a user just prior to a procedure. As noted above, the prosthetic valve <NUM> can have "dry" tissue leaflets and can be stored with the valve holder without a preserving solution. As such, any distortion of the leaflets <NUM> caused by the valve holder during storage does not permanently deform the leaflets, which can assume their normal functional shape once removed from the valve holder.

Although less convenient for a user, it should be noted that the prosthetic valve <NUM> and the valve holder <NUM> can be packaged in separate sterile containers or packages, in which case a user can mount the prosthetic valve to the valve holder in the manner described above just prior to a procedure. For example, the valve holder <NUM> can also be used to implant a prosthetic valve that is stored in a preserving solution. To avoid permanent leaflet deformation caused by the cross-linking process, it may be desirable to package the valve holder <NUM> separate from a prosthetic valve stored in a preserving solution.

To deliver and secure the prosthetic valve <NUM> to a native valve annulus, the user can secure an array of sutures to the native valve annulus, thread the sutures through the sewing ring <NUM> of the prosthetic valve <NUM>, and slide the prosthetic valve assembly <NUM> along the sutures until the prosthetic valve <NUM> sits against the native valve annulus, as known in the art. As noted above, suture looping can occur when one or more of the sutures in the parachute array inadvertently wraps around the inside of one or more of the commissure post tips. The distal end portions <NUM> extend over the commissure post tips to protect against suture looping. The curved distal end surfaces <NUM> can contact and push the sutures away from the commissure post tips as the prosthetic valve is parachuted along the suture array.

<FIG> show the process of disassembling the prosthetic heart valve assembly <NUM> and retracting the valve holder <NUM> from the prosthetic valve <NUM> once the prosthetic valve has been safely secured to a native valve annulus. First, the base <NUM> is mechanically disengaged from the base ring <NUM> and, if applicable, the prosthetic heart valve <NUM> by, for example, clipping the sutures <NUM> shown in <FIG>. Next, as shown in <FIG>, the inner body member <NUM>, which may be connected to the shaft <NUM> of a delivery tool, is retracted away from the prosthetic valve <NUM> in the proximal direction as indicated by arrow <NUM>. Retraction of the inner shaft <NUM> during this phase removes the outward radial force on the leg members <NUM> such that the distal end portions <NUM> flex inwardly of the commissure posts <NUM>, thereby exposing the commissure tips <NUM>. At this point or upon further withdrawal of the inner shaft <NUM>, the tab <NUM> comes into contact with and engages the base ring <NUM>. From this point onwards, as the inner body member <NUM> is further retracted in the proximal direction, the tab <NUM> causes the shielding member <NUM> to be retracted along with the inner body member <NUM> away from the prosthetic valve <NUM>. With the distal end portions <NUM> in their relaxed, radially inward states, the shielding member <NUM> can be retracted through the leaflets <NUM> and completely removed from the prosthetic valve <NUM> along with the inner body member <NUM>, as shown in <FIG>.

Although the inner shaft <NUM> is cylindrical and the central opening <NUM> is circular in the illustrated embodiment, the inner shaft and the central opening can have other shapes. For example, the inner shaft <NUM> can have a non-circular cross-sectional profile (in a plane perpendicular to its length) and the central opening <NUM> can be a non-circular shape, which can be the same or different shape than the cross-sectional profile of the inner shaft. Also, the inner shaft <NUM> can have a cross-sectional profile that varies along its length, such as a tapered inner shaft <NUM> (<FIG>, described below). In particular embodiments, the distal end portions <NUM> of the leg members can contact the commissure post tips <NUM>, although in alternative embodiments the leg members can be configured such that there can be a small gap between the commissure post tips <NUM> and the distal end portions <NUM>.

The inner body member <NUM> and the shielding member <NUM> can be made of any of various suitable materials, including metals or metal alloys (e.g., titanium, stainless steel, Nitinol, cobalt chromium alloys) or any of various polymeric materials, such as various polyamides, polyesters, or copolyesters. Some examples of polymers that can be used to form the inner body member <NUM> and/or the shielding member <NUM> include, without limitation, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), or polyoxymethylene (POM). In a working embodiment, the shielding member <NUM> is made of titanium and the inner body member <NUM> is made of a suitable polymer.

In alternative embodiments, different techniques and/or mechanisms can be used to flex or move the leg members <NUM> between the inward and outward positions. For example, instead of an inner shaft <NUM>, one or more levers or linkages can be operatively coupled to each of the leg members <NUM> to effect movement of the leg members between the inward and outward positions. The handle of the delivery tool can include a switch or actuator that is operably coupled to the leg members via the one or more levers or linkages such that activating the switch or actuator is effective to move the leg members <NUM>.

<FIG> shows an alternative embodiment of a prosthetic heart valve assembly <NUM> in a partially disassembled state comprising a prosthetic heart valve <NUM> and a valve holder <NUM>. <FIG> shows the valve holder <NUM> apart from the prosthetic valve <NUM>. As shown in <FIG> and <FIG>, the valve holder <NUM> in the illustrated embodiment comprises an inner body member <NUM> and an outer shielding member <NUM>. The inner body member <NUM> can comprise a base <NUM> and an inner shaft <NUM> projecting from the base <NUM>. The inner shaft <NUM> can be tapered in a direction from the distal end of the shaft toward the base <NUM> such that a distal portion <NUM> of the shaft has a greater diameter than a proximal portion of the shaft adjacent the base <NUM>. The base <NUM> can be connected to the distal end portion of a shaft <NUM> of a delivery tool. The shielding member <NUM> can comprises a base ring <NUM> defining a central opening <NUM> and a plurality of leg members <NUM> connected to and extending from the base ring <NUM>. The leg members <NUM> can have wedge-shaped distal end portions <NUM> configured to extend over and shield the commissure post tips <NUM> during delivery of the prosthetic valve <NUM>, as described above in connection with the embodiment of <FIG>.

In order to place the shielding member <NUM> around the tapered shaft <NUM> of the inner body member <NUM>, the base ring <NUM> can be formed with a slit or gap <NUM>. In this manner, the base ring <NUM> has a split-ring configuration that allows the base ring <NUM> to be splayed open and placed around the inner shaft <NUM>, as depicted in <FIG>. In particular embodiments, the inner diameter of the ring <NUM> is slightly larger than outer diameter of the proximal end portion of the inner shaft <NUM> adjacent the base <NUM>. In alternative embodiments, the base ring <NUM> need not have a split ring configuration and instead the inner body member and the shielding member can be molded, machined or otherwise formed in an assembled state with the shielding member pre-positioned around the shaft <NUM>.

To assemble the prosthetic valve <NUM> and the valve holder <NUM>, the shaft <NUM> is held in a partially retracted position relative to the shielding member <NUM> to allow the distal end portions <NUM> to remain in a non-deflected state (as depicted in <FIG> and <FIG>). With the shielding member and the inner body member in this position, the leg members <NUM> can be inserted through the prosthetic valve <NUM> (and the leaflets <NUM>) until the distal end portions <NUM> are distal to the commissure post tips <NUM>. Once the base ring <NUM> abuts the inflow end of the prosthetic valve <NUM>, the distal end portions <NUM> will be distal to, but still spaced radially inward of, the commissure post tips <NUM>. The inner shaft <NUM> can then be advanced toward distal end portions <NUM>, causing the leg members <NUM> to flex radially outwardly to position the distal end portions <NUM> over the commissure post tips <NUM>. The distal end portion <NUM> of the tapered inner shaft <NUM> can be curved or rounded as in <FIG> to assist in pushing the leg members <NUM> to the radially outward position as the shaft <NUM> is advanced through the shielding member. Once assembled, the valve holder <NUM> and the prosthetic valve <NUM> can be packaged together in a sterile container or package (with or without the shaft <NUM>).

To disengage the valve holder <NUM> from the prosthetic heart valve <NUM> after the prosthetic valve has been sutured to a native valve annulus, sutures connecting the base <NUM> to the base ring <NUM> (not shown) are severed to disengage the inner body member <NUM> from the shielding member <NUM>. The inner body member <NUM> is then retracted using a delivery tool. As the inner shaft <NUM> is withdrawn, the force from the distal portion of the inner shaft <NUM> pushing against the leg members <NUM> is removed. The distal end portions <NUM> are then able to retract to a radially inward position, thereby exposing the commissure post tips <NUM>. As the shaft <NUM> is further withdrawn, the outer surface of the shaft <NUM> comes into contact with the base ring <NUM> at a location along the shaft where the outer diameter of the shaft <NUM> approximates the inner diameter of the central opening <NUM> of the base ring <NUM>. In this manner, further retraction of the shaft <NUM> is effective to retract the shielding member <NUM> back through and away from the prosthetic valve.

<FIG> shows an alternative embodiment of a prosthetic valve assembly <NUM> comprising a prosthetic heart valve <NUM> and a valve holder <NUM>. The valve holder <NUM> in the illustrated embodiment comprises a base <NUM>, an inner shaft <NUM> extending from the base <NUM>, and a deliver tool shaft <NUM> connected to the opposite side of the base from the inner shaft <NUM>. The valve holder <NUM> can further include a plurality of distal shielding portions <NUM> spaced around the inner shaft <NUM>. The distal shielding portions <NUM> can, in a first state, be at least partially housed within respective radially extending slots (not shown) formed in the inner shaft <NUM> and, in a second state, can project radially outward from the slots.

More specifically, during assembly of the prosthetic valve <NUM> and the valve holder <NUM>, the distal shielding portions <NUM> may be retained inside the respective slots and/or the interior of the shaft such that the shielding portions <NUM> are spaced radially inwardly of the commissure post tips <NUM>. In this position, the inner shaft <NUM> and the shielding portions <NUM> can be advanced through the prosthetic valve <NUM> (and the leaflets <NUM>) toward the outflow end of the prosthetic valve. When the shielding portions <NUM> are advanced beyond the commissure post tips, the shielding portions <NUM> can be caused to project radially outwardly from the slots to extend over and shield the commissure post tips, as depicted in <FIG>. Various techniques and/or mechanisms can be employed to cause the shielding portions <NUM> to project outwardly from the slots. In one particular embodiment, for example, the shielding portions <NUM> can be spring loaded and/or can be operatively connected to an actuator or switch on the handle by a linkage assembly or lever extending through the shaft <NUM>. Actuating the actuator or switch causes the shielding members <NUM> to project outwardly from the inner shaft <NUM> to the position shown in <FIG>.

The prosthetic valve <NUM> can be delivered and sutured to a native valve annulus in the heart using the valve holder <NUM> in the manner described above by sliding or parachuting the prosthetic valve <NUM> along an array of sutures secured to the native annulus. <FIG> shows a suture <NUM> contacting the distal end of one of the shielding portions <NUM>. As the prosthetic valve is advanced toward the native annulus, the shielding portion <NUM> pushes or guides the suture <NUM> away from the commissure post <NUM> to prevent the suture from looping around the adjacent commissure post tip <NUM>. Once the prosthetic valve <NUM> is secured to the native valve annulus, the switch/actuator on the handle of the delivery tool may be activated to retract the shielding portions <NUM> radially inwardly into the slots and/or the interior of the inner shaft <NUM> so that the shielding portions are spaced radially inwardly of the commissure post tips, after which the valve holder may be retracted through the prosthetic valve <NUM> and withdrawn from the body.

In particular embodiments, holders of the present invention include members configured to shield and/or constrict the commissure posts radially inward without necessarily using sutures in tension. Sutures in tension have been used in the past to constrict the commissure posts at the time of surgery, but may be unsuitable for long-term storage due to their tendency to creep over time. If sutures were used and they creeped and stretched while stored, the commissure posts could eventually flex outward, thus defeating the intended purpose. In terms of time frame, all previous mechanisms for shielding or constricting the valve commissure posts are designed to be actuated after removal from the sterile packaging and at the time of surgery. As a matter of good surgical practices, once a surgical implant has been removed from sterile packaging it should be implanted relatively soon or discarded to protect against contamination. Thus, for the purpose of definition, embodiments described herein in which the prosthetic valves and holder assemblies are pre-assembled with the commissure posts constricted and/or shielded by portions of the holder and then stored for later use refers to storage over a duration of at least <NUM> hours, to exclude those previous mechanisms designed to be actuated at the time of surgery.

Claim 1:
A valve holder (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for a prosthetic heart valve (<NUM>, <NUM>, <NUM>), the prosthetic heart valve (<NUM>, <NUM>, <NUM>) having an inflow end (<NUM>), an outflow end (<NUM>), and plural commissure posts (<NUM>, <NUM>, <NUM>) ending in tips (<NUM>) projecting in an outflow direction, the valve holder (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a plurality of angularly spaced, leg members (<NUM>, <NUM>, <NUM>, <NUM>) configured to extend through the prosthetic valve (<NUM>, <NUM>, <NUM>) in the outflow direction,
the leg members (<NUM>, <NUM>, <NUM>, <NUM>) having distal end shielding portions (<NUM>, <NUM>, <NUM>) and being moveable between a radially outward position and a radially inward position, wherein when the leg members (<NUM>, <NUM>, <NUM>, <NUM>) are in the radially outward position, the distal end shielding portions (<NUM>, <NUM>, <NUM>) extend over and shield the tips (<NUM>) of the commissure posts (<NUM>, <NUM>, <NUM>) and wherein when the leg members (<NUM>, <NUM>, <NUM>, <NUM>) are in the radially inward position, the distal end shielding portions (<NUM>, <NUM>, <NUM>) are spaced radially inward of the commissure tips (<NUM>) and can be withdrawn through the prosthetic valve (<NUM>, <NUM>, <NUM>) in a direction toward the inflow end (<NUM>) and
the leg members (<NUM>, <NUM>, <NUM>, <NUM>) comprising respective proximal portions connected to a base ring (<NUM>, <NUM>) configured to abut the inflow end (<NUM>) of the prosthetic valve (<NUM>, <NUM>, <NUM>).