Patent Publication Number: US-2020281720-A1

Title: Retrievable prosthesis delivery system

Description:
CLAIM OF PRIORITY 
     The present application is a non-provisional of, and claims the benefit of U.S. Provisional Patent Application No. 62/815,832 filed on Mar. 8, 2019 (Attorney Docket No. 5131.018PRV), the entire contents of which are incorporated herein by reference. 
     Cross-Reference to Related Patent Documents 
     This patent application is related to U.S. Pat. No. 8,579,964 and US Patent Publication No. 2017/0165064; the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Less invasive and minimally invasive procedures are increasingly being used to treat patients for a variety of conditions in lieu of traditional open surgical techniques. For example, delivery catheters may be used for advancing a prosthesis or other device to a target area such as a diagnostic or treatment region of interest. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. 
         FIG. 1  is a schematic illustration of the left ventricle of a heart showing blood flow during systole with arrows. 
         FIG. 2  is a schematic illustration of the left ventricle of a heart having prolapsed leaflets in the mitral valve. 
         FIG. 3  is a schematic illustration of a heart in a patient suffering from cardiomyopathy where the heart is dilated and the leaflets do not meet. 
         FIG. 3A  shows, normal closure of the leaflets. 
         FIG. 3B  shows abnormal closure in the dilated heart. 
         FIG. 4  illustrates mitral valve regurgitation in the left ventricle of a heart having impaired papillary muscles. 
         FIGS. 5A-5B  illustrate the mitral valve. 
         FIG. 6  illustrates a bottom, partial cross-sectional view of an exemplary prosthetic mitral valve. 
         FIG. 7  is a perspective view of the anchor portion of the prosthetic mitral valve seen in  FIG. 6 . 
         FIG. 8A  is a perspective view of a prosthetic mitral valve. 
         FIG. 8B  is a top view from the atrium of the prosthetic valve in  FIG. 8A . 
         FIG. 9A  illustrates a perspective view of the prosthetic valve in  FIG. 8A  from the atrium. 
         FIG. 9B  illustrates a perspective view of the prosthetic valve in  FIG. 8A  from the ventricle. 
         FIG. 10  illustrates the prosthetic valve of  FIG. 8A  uncovered and unrolled in a flat pattern. 
         FIG. 11  is a side view of a delivery device for implantation of a prosthetic valve. 
         FIG. 12  is a perspective exploded view of a proximal portion of the delivery device in  FIG. 11 . 
         FIG. 13  is a perspective exploded view of a distal portion of the delivery device in  FIG. 11 . 
         FIG. 14  is a cross-section of the proximal portion of the delivery device in  FIG. 11 . 
         FIGS. 15A-15C  are cross-sectional views of a distal portion of the delivery device in  FIG. 11 . 
         FIG. 16  is a side view of another exemplary embodiment of a delivery device for implantation of a prosthetic valve. 
         FIG. 17  is a perspective view of the delivery device in  FIG. 16 . 
         FIG. 18  is a perspective exploded view of the delivery device in  FIG. 16 . 
         FIGS. 19A-19B  are side views of the delivery device in  FIG. 16  during various stages of operation. 
         FIG. 20  illustrates a distal portion of the delivery device in  FIG. 16  that is adapted to engage a portion of a prosthetic valve. 
         FIG. 21  illustrates engagement of the delivery device in  FIG. 16  with the prosthetic valve of  FIG. 8A . 
         FIGS. 22A-22G  illustrate an exemplary method of transapically delivering a prosthetic mitral valve. 
         FIGS. 23A-23G  illustrate an exemplary method of transseptally delivering a prosthetic mitral valve. 
         FIG. 24  illustrates a prosthetic mitral valve implanted in the mitral space. 
         FIG. 25  illustrates a bottom view of a mitral valve implanted in the mitral space looking upward from the left ventricle. 
         FIG. 26  is a perspective view of a transseptal delivery system for a prosthetic heart valve. 
         FIGS. 27A-27F  are sequential views of the procedural pathway traversed by the prosthesis during a transseptal implantation procedure. 
         FIGS. 28A-28D  are sequential views of the procedural pathway traversed by the prosthesis during a transaortic implantation procedure. 
         FIG. 29  is an assembly view of the delivery system seen in  FIG. 26 . 
         FIG. 30  is an assembly view of the delivery handle portion of the delivery system seen in  FIG. 26 . 
         FIG. 31  is an assembly view of the steering guide portion of the delivery system seen in  FIG. 26 . 
         FIG. 32  is an assembly view of the delivery catheter portion of the delivery system seen in  FIG. 26 . 
         FIG. 33A  is a side view of the delivery system in  FIG. 26 . 
         FIG. 33B  is a cross-sectional view of the delivery system taken along line A-A in  FIG. 33A . 
         FIGS. 33C-33D  show other cross-sections of the delivery system. 
         FIGS. 34A-34C  are cross-sectional views of the steering handle portion taken along the line A-A in  FIG. 33A . 
         FIGS. 35A-35D  are sequential views of the steering handle portion of the delivery system of  FIG. 26 . 
         FIGS. 36A-36E  are sequential cross-sectional views of the valve capsule portion taken along the line A-A in  FIG. 33A . 
         FIGS. 37A-37I  show the use of stops to control actuation of a delivery catheter. 
         FIGS. 38A-38C  show the use of tethers to control deployment of a prosthesis. 
         FIGS. 39A-39C  show stylets. 
         FIG. 40  shows a tension equalizer. 
         FIGS. 41A-41B  show an anchor element and anchor plate. 
         FIG. 42  shows a centering and tether management element. 
     
    
    
     DETAILED DESCRIPTION 
     Delivery system are used to advance a therapeutic or diagnostic device to a target area. Often times the delivery system must navigate an obstructed, tortuous, or otherwise challenging path to the target area. Therefore, it may be desirable to provide delivery systems that can accommodate the challenging path. Furthermore, sometimes once a prosthesis or other medical device is delivered to the target area and released from the delivery system, the physician determines that the prosthesis or medical device has not been delivered to the optimal location and therefore it may be desirable to move the prosthesis or medical device after it has been partially or fully deployed. Additionally, it may be desirable to provide a delivery system with controls or other indicators which allow the operator to know when critical deployment steps are performed or about to be performed, and it may be desirable to provide controls that allow an operator to acknowledge and confirm that he/she would like to proceed with the next step of deployment so that inadvertent deployment is avoided. At least some of these challenges will be addressed by the examples disclosed herein. 
     While the present examples will be discussed primarily with respect to prosthetic mitral valves used to treat mitral valve insufficiency, one of skill in the art will appreciate that this is not intended to be limiting and the examples disclosed herein may be used in any heart valve (e.g. aortic valve, tricuspid valve, pulmonary valve, etc.) as well as other anatomic valves (e.g. venous valves) or in any other region of the body. 
     Prosthetic heart valves such as prosthetic mitral valves may be implanted during an open heart procedure which is highly invasive and requires a lengthy hospital stay and recovery period. 
     More recently, prosthetic heart valves are being delivered either transapically or transseptally with a delivery system such as a delivery catheter. Examples of prosthetic valves, transapical and transseptal delivery systems are disclosed in U.S. Pat. No. 8,579,964; previously incorporated by reference. Any of the delivery systems disclosed in U.S. Pat. No. 8,579,964 may be used with any of the examples disclosed herein. 
     Additional transseptal delivery systems are disclosed in US Patent Publication No. 2017/0165064; previously incorporated herein by reference. Any of the prostheses or delivery systems disclosed in these references may be modified to include the features disclosed herein. 
     In some situations it may be desirable to add additional features to a transseptal or transapical delivery system. Any of the following features may be incorporated into a delivery system. 
     Specific embodiments of the disclosed device, delivery system, and method will now be described with reference to the drawings. Nothing in this detailed description is intended to imply that any particular component, feature, or step is essential to the invention. 
     Cardiac Anatomy. The left ventricle LV of a normal heart H in systole is illustrated in  FIG. 1 . The left ventricle LV is contracting and blood flows outwardly through the aortic valve AV, a tricuspid valve in the direction of the arrows. Back flow of blood or “regurgitation” through the mitral valve MV is prevented since the mitral valve is configured as a “check valve” which prevents back flow when pressure in the left ventricle is higher than that in the left atrium LA. The mitral valve MV comprises a pair of leaflets having free edges FE which meet evenly to close, as illustrated in  FIG. 1 . The opposite ends of the leaflets LF are attached to the surrounding heart structure along an annular region referred to as the annulus AN. The free edges FE of the leaflets LF are secured to the lower portions of the left ventricle LV through chordae tendineae CT (also referred to herein as the chordae) which include a plurality of branching tendons secured over the lower surfaces of each of the valve leaflets LF. The chordae CT in turn, are attached to the papillary muscles PM which extend upwardly from the lower portions of the left ventricle and interventricular septum IVS. 
     Referring now to  FIGS. 2-4 , a number of structural defects in the heart can cause mitral prolapse since inadequate tension is transmitted to the leaflet via the chordae. While the other leaflet LF 1  maintains a normal profile, the two valve leaflets do not properly meet and leakage from the left ventricle LV into the left atrium LA will occur, as shown by the arrow. 
     Regurgitation also occurs in the patients suffering from cardiomyopathy where the heart is dilated and the increased size prevents the valve leaflets LF from meeting properly, as shown in  FIG. 3 . The enlargement of the heart causes the mitral annulus to become enlarged, making it impossible for the free edges FE to meet during systole. The free edges of the anterior and posterior leaflets normally meet along a line of coaptation C as shown in  FIG. 3A , but a significant gap G can be left in patients suffering from cardiomyopathy, as shown in  FIG. 3B . 
     Mitral valve regurgitation can also occur in patients who have suffered ischemic heart disease where the functioning of the papillary muscles PM is impaired, as illustrated in  FIG. 4 . As the left ventricle LV contracts during systole, the papillary muscles PM do not contract sufficiently to effect proper closure. The leaflets LF 1  and LF 2  then prolapse, as illustrated. Leakage again occurs from the left ventricle LV to the left atrium LA, as shown by the arrow. 
       FIG. 5A  more clearly illustrates the anatomy of a mitral valve MV which is a bicuspid valve having an anterior side ANT and a posterior side POST. The valve includes an anterior (aortic) leaflet AL and a posterior (mural) leaflet PL. Chordae tendineae CT couple the valve leaflets AL, PL with the antero-lateral papillary muscle ALPM and the postero-medial papillary muscle PMPM. The valve leaflets AL, PL join one another along a line referred to as the antero-lateral commissure ALC and the posterior-medial commissure PMC. The annulus AN circumscribes the valve leaflets, and two regions adjacent an anterior portion of the annulus, on opposite sides of the anterior leaflet are referred to as the left fibrous trigone LFT and also the right fibrous trigone RFT. These areas are indicted by generally by the solid triangles.  FIG. 5B  more clearly illustrates the left and right fibrous trigones, LFT, RFT. 
     While various surgical techniques as well as implantable devices have been proposed and appear to be promising treatments for mitral regurgitation, surgical approaches can require a lengthy recovery period, and implantable devices have varying clinical results. Therefore, there still is a need for improved devices and methods for treating mitral regurgitation. While the embodiments disclosed herein are directed to an implantable prosthetic mitral valve for treating mitral regurgitation, one of skill in the art will appreciate that this is not intended to be limiting, and the device and methods disclosed herein may also be used to treat other cardiac valves such as the tricuspid valve, aortic valve, pulmonary valve, etc., as well as other valves in the body such as venous valves. 
     Prosthetic Valve 
     Prosthetic valves have been surgically implanted in the heart as a treatment for mitral regurgitation. Some of these valves have been valves harvested from animals such as porcine valves, and others have been prosthetic mechanical valves with or without a tissue covering. More recently, minimally invasive catheter technology has been used to deliver prosthetic valves to the heart. These valves typically include an anchor for securing the valve to the patient&#39;s heart, and a valve mechanism, either a mechanical valve, a valve with animal tissue, or combinations thereof The prosthetic valve once implanted, takes over for malfunctioning native valve, thereby reducing or eliminating valvar insufficiency. While some of these valves appear promising, there still is a need for improved valves. The following discloses exemplary embodiments of a prosthetic valve, a delivery system for the prosthetic valve, and methods of delivering the valve that overcome some of the challenges associated with existing prosthetic valves. 
     Referring now to  FIGS. 6-7 , exemplary embodiments of a mitral valve prosthesis generally designated with reference numeral  10  comprise tricuspid tissue-type prosthetic one-way valve structure  12  comprising leaflets  14  affixed within self-expanding or expandable anchor portion  16  having a geometry that expands into low profile atrial skirt region  18 , annular region  20 , ventricular skirt region  22 , and a plurality of leaflet commissures  24  (also referred to herein as commissure posts) extending axially in a cantilevered fashion downstream into the sub-annular space defined by ventricular skirt region  22 .  FIG. 6  shows a partial cross-section of the valve  10  from the patient&#39;s left ventricle looking upward toward the right atrium. The atrial skirt region  18  is anchored to a lower portion of the right atrium  19 . The valve leaflets  14  have an open position (not illustrated) and a closed position illustrated in  FIG. 6 . In the open position, the leaflets  14  are displaced away from one another to allow blood flow therepast, and in the closed position, the leaflets  14  engage one another to close the valve and prevent retrograde blood flow therepast. The valve commissures  24  may be configured to optimize the efficiency of the prosthetic valve structure  12  and the load distribution on the leaflets  14  by providing for the attachment of the leaflets  14  along arcuate seams  28  (best seen in  FIG. 7 ), and by being made selectively flexible at different points or zones along their axial length through the addition/deletion of reinforcing struts. 
       FIG. 7  shows a perspective view of the anchor portion  16  of the valve  10  which has been formed from a series of interconnected struts. The atrial skirt region  18  forms an annular flanged region on the anchor to help secure an upper portion of the prosthetic valve in the atrium, and the annular region  20  is a cylindrical region for anchoring the valve along the native valve annulus. The ventricular skirt region  22  similarly is cylindrically shaped and helps anchor a lower portion of the valve in the patient&#39;s left ventricle. Any portion, or all of the anchor may be covered with tissue such as pericardium or other tissues disclosed herein, or a synthetic material such as Dacron or ePTFE may be used to cover the anchor. The covering helps to seal the anchor to the native valve, and this helps funnel blood into and through the prosthetic valve, rather than around the valve. In some embodiments, the anchor may remain uncovered. The prosthetic valve has an expanded configuration and a collapsed configuration. The collapsed configuration has a low profile cylindrical shape that is suitable for mounting on a delivery system and delivery is preferably made either transluminally on a catheter, or transapically through the heart wall. The expanded configuration (as illustrated) allow the prosthetic valve to be anchored into a desired position. 
       FIG. 8A  illustrates a perspective view of a preferred embodiment of a prosthetic mitral valve with optional coverings removed to allow visibility of the anchor struts.  FIG. 8B  illustrates a top view of the prosthetic valve in  FIG. 8A  from the atrium looking down into the ventricle. The valve  800  includes an asymmetrical expanded anchor portion having a D-shaped cross-section. As shown, the anchor portion generally comprises anterior  802  and posterior  804  aspects along the longitudinal axis thereof, as well as atrial  806 , annular  808  and ventricular  810  regions that correspond generally to the atrial skirt  18 , annular  20  and ventricular skirt  22  regions of the embodiment described above in  FIGS. 6-7 . Commissures (also referred to herein as commissure posts)  813  also correspond generally to the leaflets  14  of the embodiment in  FIGS. 6-7 . The prosthetic valve  800  has a collapsed configuration and an expanded configuration. The collapsed configuration is adapted to loading on a shaft such as a delivery catheter for transluminal delivery to the heart, or on a shaft for transapical delivery through the heart wall. The radially expanded configuration is adapted to anchor the valve to the patient&#39;s native heart adjacent the damaged valve. In order to allow the valve to expand from the collapsed configuration to the expanded configuration, the anchor portion of the valve may be fabricated from a self-expanding material such as a nickel titanium alloy like nitinol, or it may also be made from spring temper stainless steel, or a resilient polymer. In still other embodiments, the anchor may be expandable with an expandable member such as a balloon. In preferred embodiments, the anchor is fabricated by laser cutting, electrical discharge machining (EDM), or photochemically etching a tube. The anchor may also be fabricated by photochemically etching a flat sheet of material which is then rolled up with the opposing ends welded together. 
     The atrial skirt portion  816  forms a flanged region that helps to anchor the prosthetic valve to the atrium, above the mitral valve. The atrial skirt includes a plurality of triangular fingers which extend radially outward from the anchor to form the flange. The posterior  804  portion of the atrial skirt  816  is generally round or circular, while a portion of the anterior  802  part of the atrial skirt  816  is flat. Thus, the atrial skirt region preferably has a D-shaped cross-section. This allows the prosthetic valve to conform to the patient&#39;s cardiac anatomy without obstructing other portions of the heart, as will be discussed below. Each triangular finger is formed from a pair of interconnected struts. The triangular fingers of the atrial skirt generally are bent radially outward from the central axis of the prosthetic valve and lie in a plane that is transverse to the valve central axis. In some embodiments, the atrial skirt lies in a plane that is substantially perpendicular to the central axis of the valve. The anterior portion  802  of the atrial skirt  806  optionally includes an alignment element  814  which may be one or more struts which extend vertically upward and substantially parallel to the prosthetic valve. The alignment element  814  may include radiopaque markers (not illustrated) to facilitate visualization under fluoroscopy. The alignment element helps the physician to align the prosthetic valve with the native mitral valve anatomy, as will be discussed later. 
     Disposed under the atrial skirt region is the annular region  820  which also has a collapsed configuration for delivery, and an expanded configuration for anchoring the prosthetic valve along the native valve annulus. The annular region is also comprised of a plurality of interconnected struts that form a series of cells, preferably closed. Suture holes  821  in some of the struts allow tissue or other coverings (not illustrated) to be attached to the annular region. Covering all or a portion of the anchor with tissue or another covering helps seal the anchor against the heart valve and adjacent tissue, thereby ensuring that blood is funneled through the valve, and not around it. The annular region may be cylindrical, but in preferred embodiments has a posterior portion  804  which is circular, and an anterior portion  802  which is flat, thereby forming a D-shaped cross-section. This D-shaped cross-section conforms better to the native mitral valve anatomy without obstructing blood flow in other areas of the heart. 
     The lower portion of the prosthetic valve includes the ventricular skirt region  828 . The ventricular skirt region also has a collapsed configuration for delivery, and an expanded configuration for anchoring. It is formed from a plurality of interconnected struts that form a series of cells, preferably closed, that can radially expand. The ventricular skirt in the expanded configuration anchors the prosthetic valve to the ventricle by expanding against the native mitral valve leaflets. Optional barbs  823  in the ventricular skirt may be used to further help anchor the prosthetic valve into the ventricular tissue. Barbs may optionally also be included in the atrial skirt portion as well as the annular region of the anchor. Additionally, optional suture holes  821  in the ventricular skirt may be used to help suture tissue or another material to the ventricular skirt region, similarly as discussed above. The anterior  802  portion of the ventricular skirt may be flat, and the posterior  804  portion of the ventricular skirt may be circular, similarly forming a D-shaped cross-section to anchor and conform to the native anatomy without obstructing other portions of the heart. Also, the lower portions of the ventricular skirt serve as deployment control regions since the lower portions can remain sheathed thereby constraining the ventricular skirt from radial expansion until after the optional ventricular trigonal tabs and posterior tab have expanded, as will be explained in greater detail below. 
     The ventricular skirt portion may optionally also include a pair of ventricular trigonal tabs  824  on the anterior portion of the anchor (only 1 visible in this view) for helping to anchor the prosthetic valve as will be discussed in greater detail below. The ventricular skirt may also optionally include a posterior tab  826  on a posterior portion  804  of the ventricular skirt for anchoring the prosthetic valve to a posterior portion of the annulus. The trigonal tabs  824  or the posterior tab  826  are tabs that extend radially outward from the anchor, and they are inclined upward in the upstream direction. 
     The actual valve mechanism is formed from three commissures posts (also referred to as commissures)  813  which extend radially inward toward the central axis of the anchor in a funnel or cone-like shape. The commissures  813  are formed from a plurality of interconnected struts that create the triangular shaped commissures. The struts of the commissures may include one or more suture holes  821  that allow tissue or a synthetic material to be attached to the commissures. In this exemplary embodiment, the valve is a tricuspid valve, therefore it includes three commissures  813 . The tips of the commissures may include a commissure tab  812  (also referred to as a tab) for engaging a delivery catheter. In this embodiment, the tabs have enlarged head regions connected to a narrower neck, forming a mushroom-like shape. The commissures may be biased in any position, but preferably angle inward slightly toward the central axis of the prosthetic valve so that retrograde blood flow forces the commissures into apposition with one another to close the valve, and antegrade blood flow pushes the commissures radially outward, to fully open the valve.  FIG. 8B  is a top view illustrating the prosthetic valve of  FIG. 8A  from the atrial side, and shows the preferred D-shaped cross-section. 
       FIG. 9A  illustrates the prosthetic mitral valve of  FIGS. 8A-8B  with a covering  870  coupled to portions of the anchor with suture  872 . This view is taken from an atrial perspective. In this embodiment, the covering is preferably pericardium which may come from a number of sources as disclosed elsewhere in this specification. In alternative embodiments, the covering may be a polymer such as Dacron polyester, ePTFE, or another synthetic material. The covering is preferably disposed over the annular region  820  and the ventricular skirt region  828 , and in some embodiments the anterior ventricular trigonal  824  tabs and the ventricular posterior tab  830  may also be covered with the same or a different material. The covering helps seal the anchor against the adjacent tissue so that blood funnels through the valve mechanism. In this embodiment, the atrial skirt is left uncovered, as well as tabs  824 ,  830 . Additionally, radiopaque markers  814   a  form a portion of the alignment element and facilitate visualization of the prosthetic valve under fluoroscopy which is important during alignment of the valve. 
       FIG. 9B  is a perspective view of the prosthetic mitral valve seen in  FIG. 9A , as seen from the ventricle. The struts of the valve commissures are covered with the same material or a different material as the annular and ventricular regions as discussed above, thereby forming the tricuspid valve leaflets  813 .  FIG. 9B  shows the valve in the closed configuration where the three leaflets are engaged with one another preventing retrograde blood flow. Commissure tabs  812  remain uncovered and allow the commissures to be coupled with a delivery device as will be explained below. The prosthetic valve in  FIGS. 9A-9B  may be sterilized so they are suitable for implantation in a patient using methods known in the art. 
       FIG. 10  illustrates the prosthetic valve of  FIG. 9A  with the covering removed, and the remaining anchor unrolled and flattened out. The prosthetic valve  800  is formed from a plurality of interconnected struts. For example, the atrial skirt region  806  includes a plurality of interconnected struts that form a series of peaks and valleys. The flat anterior region  802  of the prosthetic valve has its peaks and valleys axially offset from those of the remaining portion of the atrial skirt, and this region becomes a part of the alignment element  814 . Radiopaque markers  814   a  are disposed on either side of the offset peaks and valleys and help with visualization during implantation of the valve. An axially oriented connector joins the struts of the skirt region  806  with the struts of the annular region  808 . The annular region is also comprised of a plurality of axially oriented and interconnected struts that form peaks and valleys. Connector struts couple struts of the annular region with the struts of the ventricular region  810 . The ventricular region also includes a plurality of interconnected struts that form peaks and valleys. Additionally, the struts form the leaflet commissures  813 , the ventricular skirt  828 , as well as the trigonal and posterior tabs  824 ,  830 . Suture holes  821  are disposed along the struts of the annular region as well as the ventricular region to allow attachment of a cover such as pericardium or a polymer such as Dacron or ePTFE. Barbs  823  are disposed along the ventricular skirt  828  to help anchor the prosthetic valve to adjacent tissue. Commissure tabs or tabs  812  are disposed on the tips of the commissures  813  and may be used to releasably couple the prosthetic valve with a delivery system as will be described below. One of skill in the art will appreciate that a number of strut geometries may be used, and additionally that strut dimensions such as length, width, thickness, etc. may be adjusted in order to provide the anchor with the desired mechanical properties such as stiffness, radial crush strength, commissure deflection, etc. Therefore, the illustrated geometry is not intended to be limiting. 
     Once the flat anchor pattern has been formed by EDM, laser cutting, photochemical etching, or other techniques known in the art, the anchor is radially expanded into a desired geometry. The anchor is then heat treated using known processes to set the shape. Thus, the anchor may be loaded onto a delivery catheter in a collapsed configuration and constrained in the collapsed configuration with a constraining sheath. Removal of the constraining sheath will allow the anchor to self-expand into its unbiased pre-set shape. In other embodiments, an expandable member such as a balloon may be used to radially expand the anchor into its preferred expanded configuration. 
     Transapical Delivery Systems 
       FIGS. 11-15C  show a delivery apparatus  1124  fashioned to deliver a prosthetic mitral valve to the heart transapically. However, one of skill in the art will appreciate that the delivery system may be modified and relative motion of the various components adjusted to allow the device to be used to deliver a prosthetic mitral valve transseptally. The delivery apparatus is generally comprised of a handle  1101  that is the combination of a handle section  1102  and a handle section  1103  (best seen in  FIG. 12 ), as well as a flexible tip  1110  that can smoothly penetrate the apex of the heart, and a sheath catheter  1109  which houses several additional catheters that are designed to translate axially and will be described in detail below. 
     The handle  1101  includes a female threaded Luer adaptor  1113  which connects to a Tuohy Borst adaptor  1114  in order to provide a hemostatic seal with a 0.035″ diameter guide wire (not shown). The female threaded Luer adaptor  1113  is in threaded contact with the proximal section of the handle  1101  through a threaded port  1131  (best seen in  FIG. 12 ). 
     As can be seen in  FIG. 11 , the handle  1101  provides location for the control mechanisms used to position and deploy a prosthetic mitral valve. The handle  1101  provides housing for a thumbwheel  1106  that can be accessed through a window  1137  that appears on both the top and bottom of the handle  1101 . The thumbwheel  1106  internally mates with a threaded insert  1115  (best seen in  FIG. 12 ) that actuates the sheath catheter  1109 , and the mechanics of this interaction will be explained in detail below. 
       FIG. 11  also shows a deployment thumbwheel  1104  that provides linear translation to a deployment catheter  1120  (best seen in  FIG. 12 ) when turned, since the turning motion of the deployment thumbwheel  1104  acts as a power screw, pushing the peg  1128  forward and distally from the user. The mechanics behind the peg  1128  will be further detailed below. The thumbwheel lock  1105  provides a security measure against unwanted rotation of the deployment thumbwheel  1104  by acting as a physical barrier to rotation. In order to turn the deployment thumbwheel  1104  the user must push forward the thumbwheel lock  1105 , disengaging it from two slots  1147  (seen in  FIG. 12 ) in the deployment thumbwheel  1105 . 
     As can also be seen in  FIG. 11 , a bleed valve  1108  and fluid line  1107  are connected to an internal mechanism in the distal portion of the handle  1101 , which provides a hemostatic seal for the sheath catheter  1109 . The details of this connection will be described below. 
     Internal mechanics of the delivery apparatus  1124  are illustrated in detail in  FIG. 12 , and the following descriptions will reveal the interactions between individual components, and the manner in which those components combine in order to achieve a prosthetic heart valve delivery apparatus. 
     As seen in  FIG. 12 , a handle section  1103  and handle section  1102  combine to create a handle  1101  that forms the basis of the delivery apparatus  1124 . In order to advance the sheath catheter  1109  during valve loading, or retract the sheath catheter  1109  during deployment, a rotatable thumbwheel  1106  is in threaded contact (internal threads  1129  seen in  FIG. 14 ) with a threaded insert  1115  (external threads  1130  of  FIG. 13 ) that translates linearly along the axis of the delivery apparatus, from a proximal position to a distal position. The sheath catheter  1109  is in mating contact with the threaded insert  1115  and is fastened through the use of a collar  1117  that aligns and mates the collar with the insert. The collar  1117  is fastened with screws  1116  (best seen in DETAIL A in  FIG. 14 ) to the threaded insert  1115  and contains a fluid port  1142  (best seen in DETAIL A in  FIG. 14 ) that provides location for the fluid line  1117  so that hemostasis can be maintained between the patient and delivery apparatus. An O-ring  1118  (best seen in DETAIL A in  FIG. 14 ) seals the stationary catheter  1119  (best seen in  FIG. 14 ) against the sheath catheter  1109 . The fluid line  1107  also provides a means of visually locating the sheath catheter  1109  with respect to position, as a slot  1138  in the handle  1101  allows the fluid line  1107  to translate with the sheath catheter  1109  (through a hole  1151  (best seen in DETAIL A in  FIG. 14 ) during operation, and this translation is highly visible. In order to prevent rotation of the threaded insert during translation, a flat face  1164  has been machined onto both sides of the threaded insert  1115 . The flat faces  1164  remain in contact with bosses  1139  and  1140  that are located on both handle section  1102  and handle section  1103  so that the bosses  1139  and  1140  act to grip the threaded insert  1115  and prevent rotation. A textured pattern  1155  allows the user to easily turn the thumbwheel  1106  in the surgical field. Detents  1141  (best seen in  FIG. 14 ) locate flanges  63  (seen in  FIG. 14 ) on the thumbwheel  1116  in order to allow for rotation. 
     The manner in which individual catheters (there are four catheters) move with respect to each other is illustrated in  FIG. 12 . Sheath catheter  1109  provides housing for the stationary catheter  1119 , which in turn provides housing for the movable hub catheter  1120 . The hub catheter  1120  translates linearly with respect to the nose catheter  1121  which can also be translated with respect to each previous catheter, and the handle  1101 . The stationary catheter  1119  is mated to a handle section  1103  in an internal bore  1150  which also forms a seal between the stationary catheter  1119  and the hub catheter  1120 . The distal portion of the stationary catheter  1119  is formed in the shape of a bell  1122  (see DETAIL A in  FIG. 15A ) which acts as a housing to retain the hub capture  1123  (seen in DETAIL A in  FIG. 15A ). 
     As previously stated a thumbwheel lock  1105  prevents rotation of the deployment thumbwheel  1104 . In order to provide a seating force that keeps the thumbwheel lock  1105  in a locked position until manipulated, a spring  1125  is housed in an internal bore  62  (best seen in  FIG. 14 ) and abuts against a shoulder  1161  (best seen in  FIG. 14 ) that is located inside the thumbwheel lock  1105 . This spring  1125  maintains the leading edge  1149  of the thumbwheel lock  1105  in a locked position within the two slots  1147  of the deployment thumbwheel  1104 . Gripping texture  1154  is provided on the thumbwheel lock  1105  for ease of use. In order to locate and retain the thumbwheel lock  1105  inside of the handle  1101 , a slot  1135  has been provided in both a handle section  1102  and a handle section  1103 . 
     As shown in  FIG. 12 , a sliding block  1127  is housed inside of flat parallel faces  1134  which appear on the inside of the handle  1101 . This sliding block  1127  is in mating contact with hub catheter  1120  and is the physical mechanism that linearly actuates the catheter. A spring  1126  is mounted on an external post  1159  and abuts against a shoulder  1133  that is located on the distal end of the sliding block  1127 . This spring  1126  forces a peg  1128  (located inside a thru-hole  1156  of  FIG. 14 ) into contact with the proximal edge of an angled slot  1148  that is cut into the deployment thumbwheel  1104 . The deployment thumbwheel  1104  is contained between a shoulder  1136  and a snap ring (not shown), both of which are features of the handle  1101 . Gripping texture  1153  on the deployment thumbwheel  1104  allows the user to easily rotate the thumbwheel in a clockwise direction, actuating the peg  1128  to ride distally along the slot  1148  and move the sliding block  1127 , which pushes the hub catheter  1120  and hub  1123  (best seen in DETAIL A of  FIG. 15A ) forward and out of the bell  1122  (seen in DETAIL A of  FIG. 15A ). A slot  1132  appears in a handle section  1102  and a handle section  1103  and prevents the peg  1128  from translating beyond a desired range. 
     A nose catheter  1121  extends from a Tuohy Borst adaptor  1114  on the proximal end of the handle  1101 , and internally throughout the handle and the respective catheters (sheath catheter  1109 , stationary catheter  1119 , and hub catheter  1120 ), terminating inside the rigid insert  1112  (seen in  FIG. 15A ) of the flexible tip  1110  (seen in  FIG. 15A ) that abuts with the distal end of the sheath catheter  1109 . 
       FIG. 13  displays an exploded view of the tip section of the delivery apparatus  1124 , and shows the relation between prosthetic mitral valve  1165  and the internal and external catheters. When crimped and loaded, the prosthetic mitral valve  1165  is encased between the internal surface of the sheath catheter  1109  and the external surface of the nose catheter  1121 . In order to capture and anchor the prosthetic mitral valve  1165  within the delivery apparatus  1124 , three commissure tabs  1160  (circumferentially spaced at 120.degree.apart) appearing on the proximal end of the prosthetic mitral valve  1165  provide points of contact between the valve and three slots  1143  (seen in  FIG. 15A ) that are machined into the outer surface of the hub  1123  (circumferentially spaced at 120.degree.apart). After first advancing the hub catheter  1120  ( FIG. 15A ) by rotating the deployment thumbwheel  1104  (seen in  FIG. 12 ) clockwise, the three commissure tabs  1160  can be captured within the three slots  1143  (seen in  FIG. 15A ). The hub  1123  can then be retracted into the bell  1122  by releasing the deployment thumbwheel  1104  (seen in  FIG. 12 ). In this position the prosthetic mitral valve  1165  is anchored to the delivery apparatus  1124 , and further crimping of the valve will allow the sheath catheter  1109  to be advanced over the valve. 
       FIGS. 15A-15C  further detail the manner in which loading of the prosthetic mitral valve  1165  (seen in  FIG. 13 ) into the delivery apparatus  1124  can be achieved. Initially, the flexible tip  1110  is abutted against the distal edge  1157  of the sheath catheter  1109 . The flexible tip  1110  is comprised of a rigid insert  1112 , and a soft and flexible tip portion  1111  which is over-molded onto the rigid insert  1112 . The shoulder  1145  and tapered face  1146  of the rigid insert  1112  act to guide and locate the distal edge  1157  of the sheath catheter  1109 , so that the catheter may rest against and be stiffened by the flexible tip  1110 , and be more easily introduced into the apex of the heart. 
     An initial position from which loading can be achieved is illustrated in  FIG. 15A . As a first step in the loading of a prosthetic mitral valve  1165  (seen in  FIG. 13 ) into the delivery apparatus  1124 , the sheath catheter  1109  is withdrawn by rotation of the thumbwheel  1106  in a clockwise direction. The distal edge  1157  of the sheath catheter  1109  is retracted until it passes the distal edge of the bell  1122 , as illustrated in DETAIL A of  FIG. 15B . As a second step in the loading of a prosthetic mitral valve  1165  (seen in  FIG. 13 ) into the delivery apparatus  1124 , the hub  1123  is advanced from beneath the bell  1122  by clockwise turning of the deployment thumbwheel  1104  (seen in  FIG. 12 ), as illustrated in DETAIL A of  FIG. 15C . The deployment thumbwheel may only be turned once the thumbwheel lock  1105  (see  FIG. 12 ) has been set in the forward position, disengaging it from contact with the thumbwheel. Advancement of the hub  1123  uncovers three slots  1143  into which three commissure tabs  1160  of the prosthetic mitral valve  1165  (seen in  FIG. 13 ) will fit and be anchored. After anchoring of the commissure tabs  1160  into the slots  1143  by retraction of the hub  1123  has been achieved, a third step in the loading of a prosthetic mitral valve  1165  (seen in  FIG. 13 ) into the delivery apparatus  1124  may be performed. The prosthetic mitral valve  1165  (seen in  FIG. 13 ) can be crimped down to a minimum diameter by a loading mechanism (not shown), and then the sheath cannula  1109  can be advanced forward so as to cover the valve, by rotation of the thumbwheel  1106  in a counter-clockwise direction. The delivery apparatus  1124  and prosthetic mitral valve  1165  are then ready for deployment. 
       FIGS. 16-19B  illustrate another exemplary embodiment of a delivery device for implanting a prosthetic valve in the heart transapically. However, one of skill in the art will appreciate that the delivery system may be modified and relative motion of the various components adjusted to allow the device to be used to deliver a prosthetic transseptally. The delivery apparatus is generally comprised of a handle  1601  that is the combination of two halves ( 1610  and  1635 ), as well as a tip  1603  that can smoothly penetrate the apex of the heart, and a flexible sheath  1602  which is comprised of concentric catheters that are designed to translate axially and will be described in detail below. 
     The handle  1601  includes a handle cap  1611  which connects to a female threaded Luer adaptor  1612  in order to provide a sealable exit for a 0.035″ diameter guide-wire (not shown). The handle cap  1611  is attached to the handle  1601  with threaded fasteners  1613 . The female threaded Luer adaptor  1612  is in threaded contact with the handle cap  1611  through a tapped port, and when fully inserted squeezes against an O-ring ( 1636  best seen in  FIG. 18 ) which seals against the outer diameter of a guide-wire catheter ( 1621  best seen in  FIG. 18 ). 
     As can be seen in  FIG. 17 , the handle  1601  provides location for the control mechanisms used to position and deploy a prosthetic mitral valve. The handle  1601  provides housing for a thumbwheel  1616  that can be accessed through a window  1606  that appears on both the top and bottom of the handle  1601 . The thumbwheel  1616  internally mates with a threaded insert ( 1627  in  FIG. 18 ) that actuates the sheath catheter  1604 , and the mechanics of this interaction will be explained in detail below. 
       FIG. 17  also shows a first hemostasis tube  1617  that is inserted internally through a slot  1605 , and that mates with a first hemo-port through a hole ( 1625  and  1626  in  FIG. 18  respectively). The first hemostasis tube  1617  allows for fluid purging between internal catheters. The position of the first hemostasis tube  1617  along the slot  1605  provides a visual indicator as to the position of the sheath catheter  1604 , and relative deployment phase of a prosthetic mitral valve (not shown). The relationship between the connection of the first hemostasis tube  1617  and the sheath catheter  1604  will be described below. 
     As can also be seen in  FIG. 17 , a second hemostasis tube  1614  is inserted into the handle  1601  and mated to a second hemo-port ( 1629  in  FIG. 18 ) in order to allow fluid purging between internal catheters, and details of this insertion will be described below. Finally, a pin lock  1608  provides a security measure against premature release of a prosthetic mitral valve, by acting as a physical barrier to translation between internal mechanisms. Pin lock prongs  1615  rely on spring force to retain the pin lock  1608  in the handle  1601 , and a user must first pull out the pin lock  1608  before final deployment of a prosthetic valve. 
       FIG. 17  also shows how the handle  1601  is fastened together by use of threaded fasteners and nuts ( 1607  and  1639  of  FIG. 18  respectively), and countersunk locator holes  1609  placed throughout the handle length. 
     Internal mechanisms of the delivery system are illustrated in detail in  FIG. 18 , and the following descriptions will reveal the interactions between individual components, and the manner in which those components combine in order to create a system that is able to deliver a prosthetic mitral valve preferably transapically. 
     As seen in  FIG. 18 , the flexible sheath  1602  is comprised of four concentrically nested catheters. In order from smallest to largest in diameter, the concentrically nested catheters will be described in detail. The innermost catheter is a guide-wire catheter  1621  that runs internally throughout the entire delivery system, beginning at the tip  1603  and terminating in the female threaded Luer adaptor  1612 . The guide-wire catheter  1621  is composed of a lower durometer, single lumen Pebax extrusion and is stationary. It provides a channel through which a guidewire (not shown) can communicate with the delivery system. The next catheter is the hub catheter  1622  which provides support for the hub  1620  and is generally comprised of a higher durometer, single lumen PEEK extrusion. The hub catheter  1622  is in mating connection with both the hub  1622  at the distal end, and a stainless steel support rod  1634  at the proximal end. The stainless steel support rod  1634  is held fixed by virtue of a stopper  1637  that is encased in the handle  1601 . The hub catheter  1622  is stationary, and provides support and axial rigidity to the concentrically nested catheters. The next catheter is the bell catheter  1624 , which provides housing to the hub  1620  and is generally comprised of a medium durometer, single lumen Pebax extrusion, including internal steel braiding and lubricious liner, as well as a radiopaque marker band (not shown). The bell catheter  1624  translates axially, and can be advanced and retracted with respect to the hub  1620 . The bell catheter  1624  is in mating connection with the second hemo-port  1629  at the proximal end, and hemostasis between the bell catheter  1624  and the stainless steel support rod  1634  can be achieved by purging the second hemostasis tube  1614 . The bell catheter  1624  is bumped up to a larger diameter  1623  on the distal end in order to encapsulate the hub  1620 . The outermost and final catheter is the sheath catheter  1604  which provides housing for a prosthetic mitral valve (not shown), and which is able to penetrate the apex of the heart (not shown), by supporting and directing a tip  1603  and assisting in the dilation of an incision in the heart wall muscle. The sheath catheter  1604  is generally comprised of a medium durometer, single lumen Pebax extrusion, including internal steel braiding and lubricious liner, as well as radiopaque marker band (not shown). The sheath catheter  1604  translates axially, and can be advanced and retracted with respect to the hub  1620 . The sheath catheter  1604  is in mating connection with the first hemo-port  1625  at the proximal end, and hemostasis between the sheath catheter  1604  and the bell catheter  1624  can be achieved by purging the first hemostasis tube  1617 . 
     As seen in  FIG. 18 , the proximal end of the sheath catheter  1604  is in mating contact with a first hemo-port  1625 . The first hemo-port is in mating contact with a threaded insert  1627 , and an O-ring  1638 , which is entrapped between the first hemo-port  1625  and the threaded insert  1627  in order to compress against the bell catheter  1624 , creating a hemostatic seal. As the thumbwheel  1616  is rotated, the screw insert  1627  will translate, and the sheath catheter  1624  can be retracted or advanced by virtue of attachment. In order to provide adequate stiffness to dilate heart wall tissue, the distal edge of the sheath catheter  1604  will abut against a shoulder  1618  located on the tip  1603 . This communication allows the tip  1603  to remain secure and aligned with the sheath catheter  1604  during delivery, and creates piercing stiffness. 
       FIG. 18  also details the mechanism through which the bell catheter  1624  can be retracted or advanced with respect to the hub  1620 . The thumbwheel  1616  can be rotated to such an extent that the screw insert  1627  will be brought into contact with two pins  1628  that are press fit into the second hemo-port  1629 . As the bell catheter  1624  is in mating contact with the second hemo-port  1629 , further rotation of the thumbwheel  1616  will cause the second hemo-port  1629  to translate and press against a spring  1633  by virtue of connection to a second hemo-port cap  1632 . This advancement will cause the bumped larger diameter section  1623  of the bell catheter  1624  to be retracted from the hub  1620 . As the thumbwheel  1616  is rotated in the opposite direction, restoring force produced by the spring  1633  will cause the second hemo-port  1629  to be pushed in the opposite direction, drawing the bumped larger diameter section  1623  of the bell catheter  1624  back over the hub  1620 , an action that is necessary during the initial loading of a valve prosthesis. 
       FIG. 18  further details the manner in which hemostasis is achieved between the stainless steel support rod  1634  and the bell catheter  1624 . An O-ring  1631  is compressed between the second hemo-port  1629  and the second hemo-port cap  1632 , creating a seal against the stainless steel support rod  1634 . Hemostasis between the bell catheter  1624  and the stainless steel support rod  1634  can be achieved by purging the second hemostasis tube  1614 , which is in communication with the void to be purged through a slot and hole  1630 . 
     The deployment process and actions necessary to activate the mechanisms responsible for deployment are detailed in  FIGS. 19A-19B . When performed in the reverse order, these actions also necessitate the first loading of a valve (not shown) prior to surgery. 
     As seen in  FIG. 19A , manipulation of the thumbwheel  1616  will provide translational control of the sheath catheter  1604 . In order to effect the deployment of a heart valve (not shown), the user must withdraw the sheath catheter  1604  from contact with the shoulder  1618  of the tip  1603  until it passes the larger diameter section  1623  of the bell catheter  1624 . A heart valve (not shown) will reside concentrically above the guide-wire catheter  1621  in the position indicated by the leader for  1621  in  FIG. 19A , similarly as to the embodiment illustrated in  FIG. 13 . The sheath catheter  1604  can be withdrawn until the screw insert  1627  comes into contact with the pin lock  1608 . The pin lock  1608  must then be removed before further travel of the screw insert  1627  can be achieved. 
     As seen in  FIG. 19B , the pin lock  1608  is removed from the handle  1601  in order to allow further translation of the sheath catheter  1604 . When the sheath catheter  1604  is fully retracted, the larger diameter section  1623  of the bell catheter  1624  is also fully retracted, which completely frees the heart valve (not shown) from the delivery system. Three hub slots  1619 , spaced circumferentially at 120.degree. from each other provide the anchoring mechanism and physical link between delivery system and heart valve. Once the larger diameter section  1623  of the bell catheter  1624  has been withdrawn, the hub slots  1619  become uncovered which allows the heart valve anchor (not shown) to fully expand. 
       FIG. 20  illustrates a distal portion of the delivery device in  FIG. 16 . Three hub slots  1619  are slidably disposed distally relative to the large diameter tip  1623  of bell catheter  1624 . These slots allow engagement with a prosthetic valve. The valve may be releasably held by the slots by disposing the commissure tabs or tabs  812  of the prosthetic valve into slots  1619  and then retracting the slots  1619  under tip  1623  of bell catheter  1624 . The prosthetic valve may be released from the delivery catheter by advancing the slots distally relative to the bell catheter so that the loading anchors or tabs  812  may self-expand out of and away from slots  1619  when the constraint of tip  1623  on bell catheter  1624  has been removed. 
       FIG. 21  illustrates a prosthetic mitral valve  800  (as discussed above with reference to  FIG. 8A ) with the anchor tabs  812  disposed in the hub slots (not visible), and bell catheter  1623  advanced thereover. Thus, even though most of the prosthetic valve  800  has self-expanded into its expanded configuration, the valve commissures remain in a collapsed configuration with the tabs  812  captured in slots  1619 . Once the constraint provided by bell catheter  1623  has been removed from the slots  1619 , the tabs  812  may self-expand out of slots  1619 , the commissures will open up to their unbiased position. The prosthetic valve is then disconnected and free from the delivery device. 
     Transapical Delivery Methods 
       FIGS. 22A-22G  illustrate an exemplary method of transapically delivering a prosthetic mitral valve. This embodiment may use any of the prosthetic valves described herein, and may use any of the delivery devices described herein.  FIG. 22A  illustrates the general transapical pathway that is taken with entry into the heart at the apex  2202 , through the left ventricle  2204 , across the mitral valve  2206  and into the left atrium  2208 . The aortic valve  2210  remains unaffected. Transapical delivery methods have been described in the patent and scientific literature, such as in International PCT Publication No. WO2009/134701, the entire contents of which are incorporated herein by reference. 
     In  FIG. 22B  a delivery device  2214  is introduced through an incision in the apex  2202  and over a guidewire GW through the ventricle  2204 , past the mitral valve  2206  with a distal portion of the delivery device  2214  disposed in the atrium  2208 . The delivery device has a rounded tip  2212  that is configured to pass through and dilate the incision, and can be advanced through the heart without causing unwanted trauma to the mitral valve  2206  or adjacent tissue. Suture  2216  may be stitched around the delivery device  2214  at the apex  2202  using a purse string stitch or other patterns known in the art in order to prevent excessive bleeding and to help hold the delivery device in position. 
     In  FIG. 22C , the outer sheath  2214   a  of the delivery device  2214  is retracted proximally relative to the prosthetic mitral valve  2220  (or the prosthetic mitral valve is advanced distally relative to the outer sheath  2214   a ) to expose the alignment element  2218  and a portion of the atrial skirt region  2222  on the prosthetic mitral valve  2220  which allows the atrial skirt region  2222  to begin to partially radially expand outward and flare open. Alignment element  2218  may include a pair of radiopaque markers  2218   a  which facilitate visualization under fluoroscopy. The physician can then align the alignment element so that the radiopaque markers  2218   a  are disposed on either side of the anterior mitral valve leaflet. Delivery device  2214  may be rotated in order to help align the alignment element. The alignment element is preferably situated adjacent the aortic root and between the fibrous trigones of the native anterior leaflet. 
     In  FIG. 22D  once alignment has been obtained, the sheath  2214   a  is further retracted proximally, allowing radial expansion of the atrial skirt  2222  which flares outward to form a flange. Proximal retraction of the delivery device  2214  and prosthetic valve  2220  seat the atrial skirt  2222  against an atrial surface adjacent the mitral valve  2206  thereby anchoring the prosthetic valve in a first position. 
       FIG. 22E  shows that further proximal retraction of sheath  2214   a  exposes and axially removes additional constraint from the prosthetic valve  2220 , thereby allowing more of the valve to self-expand. The annular region  2224  expands into engagement with the mitral valve annulus and the ventricular trigonal tabs  2226  and the posterior tab  2228  radially expand. Portions of the ventricular skirt serve as deployment control regions and prevent the entire ventricular skirt from expanding because they are still constrained. The tabs are captured between the anterior and posterior mitral valve leaflets and the ventricular wall. The posterior ventricular anchoring tab  2228  is preferably aligned in the middle of the posterior mitral valve leaflet where there is an absence of chordae attachments, and is passed over the posterior leaflet to seat between the posterior leaflet and the ventricular wall. The two ventricular trigonal anchoring tabs  2226  are positioned on either side of the anterior leaflet with their heads positioned at the fibrous trigones. Slight rotation and realignment of the prosthesis can occur at this time. As the prosthesis expands, the anterior trigonal tabs anchor against the fibrous trigones, capturing the native anterior leaflet and chordae between the tabs and the anterior surface of the prosthetic valve, and the posterior ventricular tab anchors between the ventricular wall and the posterior leaflet, capturing the posterior leaflet between the posterior anchoring tab and the posterior surface of the prosthetic valve assembly. 
       FIG. 22F  shows that further retraction of sheath  2214   a  releases the ventricular trigonal tabs and the posterior tab and the deployment control regions of the ventricular skirt  2230  are also released and allowed to radially expand outward against the native mitral valve leaflets. This creates a sealing funnel within the native leaflets and helps direct blood flow through the prosthetic mitral valve. With the commissures of the prosthesis still captured within the delivery system, very minor adjustments may still be made to ensure accurate positioning, anchoring and sealing. The prosthetic valve is now anchored in four positions. The anchor tabs  2232  are then released from the delivery device by retraction of an inner shaft, allowing the tabs to self-expand out of slots on the delivery catheter as previously discussed above and shown in  FIG. 22G . The prosthetic valve is now implanted in the patient&#39;s heart and takes over the native mitral valve. The delivery device  2214  may then be removed from the heart by proximally retracting it and removing it from the apex incision. The suture  2216  may then be tied off, sealing the puncture site. 
     Transseptal Delivery Methods 
       FIGS. 23A-23G  illustrate an exemplary method of transseptally delivering a prosthetic mitral valve. This embodiment may use any of the prosthetic valves described herein, and may use any of the delivery devices described herein if modified appropriately. One of skill in the art will appreciate that relative motion of the various shafts in the delivery system embodiments disclosed above may need to be reversed in order to accommodate a transseptal approach.  FIG. 23A  illustrates the general transseptal pathway that is taken with the delivery device passing up the vena cava  2302  into the right atrium  2304 . A transseptal puncture  2306  is created through the atrial septum, often through the foramen ovale, so that the device may be passed into the left atrium  2308 , above the mitral valve  2310  and adjacent the left ventricle  2312 . Transseptal techniques have been published in the patent and scientific literature, such as in U.S. Patent Publication No. 2004/0181238 to Zarbatany et al., the entire contents of which are incorporated herein by reference. 
     In  FIG. 23B  a delivery device  2314  is passed over a guidewire GW through the vena cava  2302  into the right atrium  2306 . The delivery device  2314  is then transseptally passed through the atrial wall into the left atrium  2308  adjacent the mitral valve  2310 . The guide-wire GW may be disposed across the mitral valve  2310  in the left ventricle  2312 . The distal tip of the delivery device typically includes a nose cone or other atraumatic tip to prevent damaging the mitral valve or adjacent tissue. 
     In  FIG. 23C , the outer sheath  2214   a  of the delivery device  2214  is retracted proximally relative to the prosthetic mitral valve  2319 . Alternatively, a distal portion  2314   b  of the delivery device  2214  may be advanced distally relative to the prosthetic valve  2319  to expose the alignment element  2316  and a portion of the atrial skirt region  2318  on the prosthetic mitral valve  2319  which allows the atrial skirt region  2318  to begin to partially radially expand outward and flare open. Alignment element  2316  may include a pair of radiopaque markers  2316   a  which facilitate visualization under fluoroscopy. The physician can then align the alignment element so that the radiopaque markers  2316   a  are disposed on either side of the anterior mitral valve leaflet. The alignment element is preferably situated adjacent the aortic root and between the fibrous trigones of the native anterior leaflet. Delivery device  2214  may be rotated in order to help align the alignment element. 
     In  FIG. 23D  once alignment has been obtained, the distal portion  2314   b  is further advanced distally allowing radial expansion of the atrial skirt  2318  which flares outward to form a flange. Distally advancing the delivery device  2214  and prosthetic valve  2319  seats the atrial skirt  2318  against an atrial surface adjacent the mitral valve  2310  thereby anchoring the prosthetic valve in a first position. 
       FIG. 23E  shows that further distal advancement of distal portion  2314   b  exposes and axially removes additional constraint from the prosthetic valve  2319 , thereby allowing more of the valve to self-expand. The annular region  2320  expands into engagement with the mitral valve annulus and the ventricular trigonal tabs  2324  and the posterior tab  2322  radially expand. Portions of the ventricular skirt serve as deployment control regions since they remain constrained and thus the entire ventricular skirt cannot expand. The tabs are captured between the anterior and posterior mitral valve leaflets and the ventricular wall. The posterior ventricular anchoring tab  2322  is preferably aligned in the middle of the posterior mitral valve leaflet where there is an absence of chordae attachments, and is passed over the posterior leaflet to seat between the posterior leaflet and the ventricular wall. The two ventricular trigonal anchoring tabs  2324  are positioned on either side of the anterior leaflet with their heads positioned at the fibrous trigones. Slight rotation and realignment of the prosthesis can occur at this time. As the prosthesis expands, the anterior trigonal tabs anchor against the fibrous trigones, capturing the native anterior leaflet and chordae between the tabs and the anterior surface of the prosthetic valve, and the posterior ventricular tab anchors between the ventricular wall and the posterior leaflet, capturing the posterior leaflet between the posterior anchoring tab and the posterior surface of the prosthetic valve assembly. 
       FIG. 23F  shows that further distal advancement of distal portion  2314   b  releases the ventricular trigonal tabs and the posterior tab and the ventricular skirt  2326  is also released and allowed to radially expand outward against the native mitral valve leaflets without engaging the ventricular wall. This creates a sealing funnel within the native leaflets and helps funnel blood flow through the prosthetic valve. With the commissures of the prosthetic valve still captured by the delivery system, very minor adjustments may still be made to ensure accurate positioning, anchoring and sealing. The prosthetic valve is now anchored in four positions. The anchor tabs  2328  are then released from the delivery device by further advancement of an inner shaft, allowing the tabs to self-expand out of slots on the delivery catheter as previously discussed above and shown in  FIG. 23G . The prosthetic valve is now implanted in the patient&#39;s heart and takes over the native mitral valve. The delivery device  2314  may then be removed from the heart by proximally retracting it back through the atrial septum, and out of the vena cava. 
       FIG. 24  shows the prosthetic valve  2418  anchored in the mitral space after transapical or transseptal delivery. Prosthetic valve  2418  is preferably the prosthetic mitral valve illustrated in  FIG. 8A , and delivered by methods shown in  FIGS. 22A-22G  or  FIGS. 23A-23G . The prosthetic valve  2418  has radially self-expanded into engagement with the mitral valve to anchor it in position without obstructing other portions of the heart including the left ventricular outflow tract such as aortic valve  2402 . The anterior trigonal tabs  2408  (only 1 seen in this view) and the posterior ventricular tab  2405  are radially expanded outward from the rest of the ventricular skirt  2410  and the anterior leaflet  2406  and posterior leaflet  2404  are captured between the respective tab and the ventricular skirt  2410  to form an anchor point. The ventricular skirt  2410  is also radially expanded outward to engage and press outwardly at least some of the chordae tendineae and papillary muscles but preferably without pressing against the ventricular wall. The annular region  2416  is expanded radially outward to engage and press against the mitral valve annulus, and the atrial skirt  2414  has also expanded outwardly to form a flange that rests on top of the mitral valve against the atrium. Thus, the prosthetic valve  2418  is anchored in four positions in the mitral space which prevents the prosthetic valve from migrating or dislodging during contraction of the heart. Moreover, using four anchor points lessens the anchoring pressure that is required to be applied in any given anchoring zone as compared to a prosthesis that is anchored in only a single anchoring zone, or in any combination of these four anchoring zones. The consequent reduction in radial force required to be exerted against the native structures in each zone minimizes the risk of obstruction or impingement of the nearby aortic valve or aortic root caused by the displacement of the native mitral valve apparatus. Valve leaflets  2420  form a tricuspid valve which opens with antegrade blood flow and closes with retrograde blood flow. Tab  2412  on a tip of the commissures  2421  (best seen in  FIG. 25 ) remains free after disengagement from the delivery device. 
       FIG. 25  illustrates the prosthetic valve  2418  of  FIG. 24  anchored in the mitral space and viewed from the left ventricle, looking upward toward the atrium. As previously mentioned, the prosthetic valve  2418  may be transapically or transseptally delivered and is preferably the prosthetic mitral valve illustrated in  FIG. 8A , delivered by methods shown in  FIGS. 22A-22G  or  FIGS. 23A-23G . This view more clearly illustrates anchoring and engagement of the prosthetic mitral valve  2418  with the adjacent tissue. For example, the three valve leaflets  2420  forming the tricuspid valve are shown in the open position, allowing blood flow therepast. Additionally, the anterior trigonal tabs  2408  and the posterior ventricular tab  2405  are shown radially expanded outward into engagement with the ventricular heart tissue  2425 . The anterior portion of the prosthetic valve in between anterior trigonal tabs  2408  is approximately flat to match the corresponding flat anatomy as previously discussed above. The flat shape of the anterior portion of the prosthetic valve prevents the prosthetic valve from impinging on and obstructing adjacent anatomy such as the left ventricular outflow tract including the aortic valve.  FIG. 25  also illustrates how the ventricular skirt  2410  expands radially outward against the native mitral valve leaflets. 
     Drug Delivery 
     Any of the prosthetic valves disclosed herein may also be used as a drug delivery device for localized drug elution. The therapeutic agent may be a coated on the prosthetic valve, on the tissue covering the anchor, on both, or otherwise carried by the prosthetic valve and controllably eluted therefrom after implantation. Exemplary drugs include anti-calcification drugs, antibiotics, anti-platelet aggregation drugs, anti-inflammatory drugs, drugs which inhibit tissue rejection, anti-restenosis drugs, anti-thrombogenic drugs, thrombolytic drugs, etc. Drugs which have these therapeutic effects are well known to those of skill in the art. 
     Transseptal Delivery System 
     Referring to  FIG. 26 , one example of a transseptal delivery system for transcatheter heart valve delivery is depicted generally as  2601 . In the drawings and in the descriptions which follow, the term “proximal” will refer to the end  2602  of the delivery system that is closest to the user, while the term “distal” will refer to the end  2603  that is farthest from the user. The transseptal delivery system  2601  can comprise a prosthesis such as a prosthesis capsule or valve capsule assembly  2608 , a delivery catheter assembly  2607 , a steering guide  2610 , a delivery handle assembly  2604 , and an interface  2609  between the delivery handle  2604  and steering handle  2605 . The steering guide  2610  can be comprised of a steerable catheter assembly  2606  and a steering handle  2605 . The valve capsule assembly  2608  can be in operable communication with the delivery handle assembly  2604  by way of the delivery catheter assembly  2607  which extends therebetween. The translational position and angular attitude of the prosthesis or valve capsule assembly  2608  can be operably controlled by the steering handle  2605  and in communication by way of the steerable catheter assembly  2606  which extends therebetween. The interface  2609  can be comprised of a slidable seal, such as an O-ring type seal. The interface  2609  can further function to allow the delivery handle or delivery catheter to translate within the steering handle while maintaining some stiction, thus preventing blood or other fluid from seeping out of the steering handle should such blood or fluid make its way up the steering catheter assembly. 
     Further details of a transcatheter mitral valve or any prosthesis that may be used with any of the delivery devices described herein, along with other related delivery catheters are described herein and in commonly owned U.S. Pat. No. 8,579,964 to Lane et. al., the entire contents of which are incorporated by reference herein. 
     Generally, delivery handle assembly  2604  includes a distal actuator such as a thumbwheel  2611  and a proximal actuator such as a thumbwheel  2612 , both of which are integrally associated with the delivery handle assembly  2604 , which is comprised of an A-side deli very handle housing  2622 , and a B-side delivery handle housing  2623 . Distal thumbweel  2611  and proximal thumbwheel  2612  are also rotatably positionable with respect to the delivery handle assembly  2604 , serving as actuators by way of internal threads (not shown) and enabling translational control of various catheters within the delivery catheter assembly  2607 , further evidence of which will be detailed in a later section. The delivery handle assembly  2604  is operatively coupled to the valve capsule assembly  2608  via the delivery catheter assembly  2607 , which functions in one aspect as a motion translation agent. In some embodiments, the delivery handle assembly  2604 , delivery catheter assembly  2607  and valve capsule assembly  2608  can form a delivery system  2626 . In some embodiments, the steering handle  2605  and steerable catheter assembly  2607  can form a steering guide  2610 , which provides a path through which the delivery system  2626  can translate and rotate, and from which it may take its shape in order to traverse tortuous vasculature during implantation. Taken altogether, the delivery system  2626  and steering guide  2610  can form the transseptal delivery system  2601 . 
     Valve capsule assembly  2608  may exhibit various constructions. For example, the distal capsule  2614  and proximal capsule  2613  may be formed from substantially rigid, stainless steel, polymer, metal or otherwise rigid tubing, from collapsible, flexible tubing, or from shape-settable exotic metal alloys which exhibit shape memory characteristics and are actuated by temperature gradients inherent to the human physiology, such as nitinol. Presently, portions of the valve capsule assembly  2608  can be translatably controlled by the turning of either the distal thumbwheel  2611 , or the proximal thumbwheel  2612 , located in the delivery handle assembly  2604 . By rotating the distal thumbwheel  2611 , the proximal capsule  2614  can be translatably positioned along the axis of the capsule assembly  2608  in order to reveal certain portions of the prosthesis such as a prosthetic mitral valve for example, that is entrained within. By rotating the proximal thumbwheel  2612 , the proximal capsule  2613  can be translatably positioned along the axis of the valve capsule assembly  2608 , again preferably revealing and releasing certain portions of the prosthetic valve (not shown). Capsule variations will be described in detail in a later section. 
     With reference to  FIG. 32 , the delivery catheter assembly  3206  is generally comprised of a family of nested catheters concentrically and slidably disposed over one another. The innermost catheter in the family of nested catheters is the guidewire catheter  3230  which has a distal section  3232  that is coupled to the distal capsule  3214 , and a proximal section  3231 , with a guidewire lumen  3233  that is generally sized to accept a guidewire running therebetween. The guidewire catheter  3230  has a constant outer diameter and a constant inner diameter throughout its entire length, as well as a flexible section  32300  which allows for articulation. The guidewire catheter  3230  is generally configured to be able to fit inside of and translate slidably with respect to the bell catheter  3234 . The bell catheter  3234  has a distal section  32360  that is coupled to a bell  3236 , wherein the bell can be generally cylindrically shaped having a diameter larger than the bell catheter, and a proximal section  3235 , with an inner lumen  32361  that is generally sized to accept the guidewire catheter  3230  running therebetween. The bell catheter  3234  has a constant outer diameter and a constant inner diameter throughout its entire length, as well as a flexible section  32301  which allows for articulation. The bell catheter  3234  is generally configured to be able to fit inside of and slidably translate with respect to the anchoring catheter  3237 . The anchoring catheter  3237  has a distal section  3239  that is coupled to an anchor  32400 , wherein the anchor can be generally cylindrically shaped and have a plurality of anchoring slots circumferentially positioned to receive valve commissure anchoring portions (not shown), and a proximal section  3238 , with an inner lumen  3240  that is generally sized to accept the bell catheter  3234  running therebetween. The anchoring catheter  3237  has a constant outer diameter and a constant inner diameter throughout its entire length, as well as a flexible section  32302  which allows for articulation. The anchoring catheter  3237  is generally configured to be able to fit inside of and translate with respect to the sheath catheter  3241 . The sheath catheter  3241  has a distal section  3243  that is coupled to the proximal capsule  3213 , wherein the proximal capsule can have a cylindrical portion terminating in a cap portion, and wherein the cap portion can have a rounded dome-like surface, and a proximal section  3242 , with an inner lumen  32130  that is generally sized to accept the anchoring catheter  3237  running therebetween. The sheath catheter  3241  has a constant outer diameter and a constant inner diameter throughout its entire length, as well as a flexible section  32303  which allows for articulation. The sheath catheter  3241  is generally configured to be able to fit inside of and slidably translate with respect to the steering catheter assembly  3206 . The steering catheter assembly  3206  is comprised of a steerable catheter  32309 , a pull ring  32307 , wherein the pull ring can have a circular ring-like shape located at the distal section  32305  of the catheter, a plurality of pull wires  32308  located at the proximal section of the catheter, a flexible section  32304  that allows for articulation, and an inner lumen  32310  running throughout the entire length. For each pull wire  32308  there is a corresponding lumen (not shown) that runs the entirety of the steerable catheter  32309 . 
     Generally, the steering guide  2610  includes an interface section  2609  that is comprised of an O-ring type interface of cylindrical shape similar to a gasket, which is embedded within A and B side steering handle housings  2624  and  2625  respectively, the A-side steering handle housing  2624 , the B-side steering handle housing  2625 , an actuator such as a steering thumbwheel  2616 , wherein the steering thumbwheel can have a generally cylindrical shape, a catheter strain relief  2627 , and a steerable catheter assembly  2606 . The steering thumbwheel can additionally include one or more protrusions separated by one or more recesses or slots to provide a surface to facilitate grasping and turning the wheel. In some embodiments, the steering thumbwheel can have a textured surface with ribs to facilitate grasping and turning the wheel. The interface section  2609  provides a dynamic seal between the steering handle  2605  and the delivery catheter assembly  2607  thus allowing for slidably sealed catheter translation thereby; the delivery catheter assembly thus may traverse therethrough and exit towards the distal end of the steering guide  2610  at the terminal, articulated end  2615  of the steerable catheter assembly  2606 . While the interface section  2609  provides a dynamic seal, the delivery catheter assembly  2607  may still translate and rotate within the steering guide  2610 , in order to define accurate positioning within a patient, at the target implant site. Detail regarding the implant procedure and target implant site will be discussed in a later section. In order to actuate the steerable portion of the steering catheter assembly  2606 , the steering thumbwheel  2616  must be turned. When the steering thumbwheel  2616  is turned, the articulated end  2615  of the steerable catheter assembly  2606  will bend in the same direction as the direction of thumbwheel turning. This motion translation is achieved through the use of internal pull wires  32308 , as depicted for example in  FIG. 32 , that are distally in mated connection (such as a welded connection, or using fasteners, or adhesives, or any suitable method of fastening) with a pull ring  32307 , and proximally connectably communicate with the internal mechanisms which are inherent to the steering handle  2605  and will be described in further detail in a later section. 
     Turning now to  FIGS. 27A-27F , the sequence of steps generally followed during a transseptal valve implantation are incorporated for reference.  FIG. 27A  describes a general depiction of a partial view (with anterior ventricular surface, pulmonary trunk, and aorta removed) of a human heart  27800 . The steering guide  2607  will follow a guidewire  27811  that has previously been placed in order to provide a path that leads to the target implant site. During a typical procedure, the steering guide  2607  will enter the inferior vena cava  27810  by way of the descending inferior vena cava (not shown) and first an incision at the femoral vein near the groin (not shown). The steering guide  2607  will then exit the inferior vena cava  27810  through a caval foramen  27801  which acts as an inlet to the right atrium  27802  ( FIG. 27B ). Once in the right atrium  27802 , the steering guide  2607  will then penetrate the foramen ovale  27803  in the septal wall and gain access to the left atrium  27804 . At the left atrium  27804  ( FIG. 27C ), the steering guide  2610  will be aimed towards the mitral annulus  27805  in order to provide a direct channel towards the implant site (mitral annulus  27805 ) for the delivery catheter  27812  ( FIG. 27D ) to operate within. Once at the target implant site ( FIG. 27E ), the delivery catheter  27812  will operate to deploy the prosthetic valve  27808 . Once the valve  27808  has been deployed, the delivery catheter  27812  can be fully removed ( FIG. 27F ). 
     Again turning, now to  FIGS. 28A-28D , the sequence of steps generally followed during a transaortic valve implantation are incorporated for reference.  FIG. 28A  describes a general depiction of a partial view (with anterior ventricular surface, pulmonary trunk, and aortic root surface removed) of a human heart  28800 . The steering guide  2607  will again follow a guidewire  28811  that has previously been placed in order to provide a path that leads to the target implant site. During a typical procedure, the steering guide  2607  will enter the descending aorta  28813  by way of an incision at the femoral artery near the groin (not shown). The steering guide  2607  will then continue up the descending aorta  28813  and cross the aortic arch  28814  before passing through the aortic valve  28815  and descending into the left ventricular outflow tract  28816  (LVOT). After emerging from the LVOT  28816 , and entering the left ventricle  28817 , the steering guide  2607  must then make a sharp turn and point upward and towards the mitral annulus  28805 . At this point, the delivery catheter  28812  may be advanced within the steering guide  287  in order to approach the target implant site (mitral annulus  28805 ). Once at the target implant site ( FIG. 27E ), the delivery catheter  28812  will operate to deploy the prosthetic valve  28808 . Once the valve  28808  has been deployed, the delivery catheter  28812  can be fully removed ( FIG. 27F ). 
     With particular reference to  FIGS. 29-32 , the internal mechanisms of the transseptal delivery system  2601  that permit functionality will be described. Specifically,  FIG. 29  illustrates an example of an assembly of a transseptal delivery system  2601  shown in exploded view. The transseptal delivery system  2601  is displayed in sections in order to make description of the internal parts more easily understood. Delivery handle section  29403  will be described in further detail below with reference to  FIG. 30 . Steering handle section  29402  will be described in further detail below with reference to  FIG. 31 . Finally, delivery catheter section  29401  has previously been described above with reference to  FIG. 32 . 
     Referring now to  FIG. 30 , the delivery handle section  30403  is generally comprised of an A-side delivery handle housing  30022  that is in mating connection with a B-side delivery handle housing  30023 , actuators such as a plurality of thumbwheels (distal thumbwheel  2611  and proximal thumbwheel  2612 ), a plurality of force transferring leadscrews (distal leadscrew  30503  and proximal leadscrew  30511 ) that may translate proximally or distally depending on the rotation of the thumbwheel within said plurality of thumbwheels, a plurality of hemostatic ports and related tubing (hemo port A  2621 , hemo port B  2620 , hemo port C  2618  and hemo port D  2619 ) which provide the ability to remove entrained air boluses from concentrically nested catheters within the system, and various other components and fasteners that shall be described in further detail. Referring specifically to the motion transferring elements of the delivery handle section  30403 , a distal leadscrew  30503  is in threaded connection with a distal thumbwheel  30011  and by turning said distal thumbwheel  30011 , translational motion is imparted upon the distal leadscrew  30503 . The motion of the distal leadscrew  30503  is transferred to the sheath catheter  3241  by way of a connection between the proximal end  3242  of the sheath catheter  3241  and the distal end  305010  of the distal leadscrew cap  30501 , which itself is mated with adhesive (medical grade UV cure adhesive, or medical grade cyanoacrylate adhesive, or any suitable medical grade adhesive for plastics or polymers, etc.) to the distal leadscrew  30503 . The distal leadscrew cap  30501  also permits the ejection of air by way of a sealed interface (distal O-ring  30502 ) between the sheath catheter  3241  and the anchoring catheter  3237 , and an outlet hemo port A  2621 . A stationary screw cap  30504  is entrained within the A and B side handle housings  30022 ,  30023  respectively, and provides location and retention for the anchoring catheter  3237 , whereby the proximal end  3238  of the anchoring catheter  3237  is in mated connection (medical grade UV cure adhesive, or medical grade cyanoacrylate adhesive, or any suitable medical grade adhesive for plastics or polymers, or by way of fastening mechanical threads) with the distal end  305040  of the stationary screw cap  30504 . The stationary screw cap  30504  also permits the ejection of air by way of a sealed interface (medial O-ring  30505 ) between the anchoring catheter  3237  and the bell catheter  3234 , and an outlet hemo port B  2620 . A proximal leadscrew  300511  is in threaded connection with a proximal thumbwheel  30012  and by turning said proximal thumbwheel  30012 , translational motion is imparted upon the proximal leadscrew  300511 . The motion of the proximal leadscrew  300511  is transferred to the guidewire catheter  3230  by way of a connection between the proximal end  3231  of the guidewire catheter  3230  and the distal end  305110  of the proximal leadscrew  300511 . Proximal leadscrew  300511  motion is also transferred to the bell catheter  3234  by way of a slidable interference between the distal end  305110  of the proximal leadscrew  300511  and the proximal leadscrew plate  30510 , whereby the proximal leadscrew plate  30510  is in mated connection with the proximal leadscrew cap  30508 , and the proximal leadscrew cap  30508  houses the proximal end  3235  of the bell catheter  3234 . The proximal leadscrew cap  30508  also permits the ejection of air by way of a sealed interface (proximal O-ring  30509 ) between the bell catheter  3234  and the guidewire catheter  3230 , and an outlet hemo port C  2619 . The proximal leadscrew  300511  permits the ejection of air by way of an outlet hemo port D  2618  which is in mated connection with the proximal leadscrew  300511 . 
     Referring now to  FIG. 31 , the steering handle section  31402  is generally comprised of an A-side steering handle housing  31024  that is in mating connection with a B-side steering handle housing  31025 , a steerable catheter assembly  2606  that is in mating connection with a catheter strain relief  2627 , an interface  2609 , a plurality of rotatable disks (B-side rotatable disk  31600  and A-side rotatable disk  31607 ), a steering thumbwheel  31016 , a push button  31613 , and various other components and fasteners that shall be described in further detail. Referring specifically to the steering elements of the steering handle section  31402 , a steering thumbwheel  31016  is in mating connection with a locking hub  31608  that is centered within the A-side rotatable disk  31607 . The A-side rotatable disk  31607  and B-side rotatable disk  31600  are coupled together by way of a plurality of carrier rods  31601 , and work mechanically to spin within the handle housing that is comprised of the A-side steering handle housing  31024  and B-side steering handle housing  31025 . Since the A-side rotatable disk  31607  is connected to the steering thumbwheel  31016 , rotation of the steering thumbwheel  31016  causes rotation of the A-side rotatable disk  31607 . A specific function of the plurality of rotatable disks (B-side rotatable disk  31600  and A-side rotatable disk  31607 ) is to actuate the plurality of pull wires  31308  by way of tensioning hinges  31602  that may spin freely on the carrier rods  31601  and that are also connected to the pull wires  31308  and also apply tension to them when turned. Referring now specifically to the locking elements of the steering handle section  31402 , a push button  31613  is in threaded connection with a push button pin  31611  that acts as a shaft. The push button  31613  is located within a cavity  316131  that allows for direct translation when the button is depressed. A push button spring  31612  is housed between the inside surface of the push button  31613 , and the bottom of the cavity  316131  and provides return force for when the depressed push button  31613  is released. Motion from the push button  31613  is transferred along the push button pin  31611  directly to a cross bar  31604  that is fastened to the push button pin  31611  by way of a setscrew  31605 . When the push button pin  31611  translates as the push button  31613  is depressed, the cross bar  31604  also translates and a plurality of cross bar pegs  316041  that are located on the ends of the cross bar  31604  thus translate as well. When in an un-depressed state, the cross-bar pegs  316041  are seated within a plurality of slots  316071  that appear on the periphery of the A-side rotatable disk  31607 . The cross bar pegs  316041  then also project through the slots  316071  and may rest within any of the circumferential slits  31610  that appear in an array about the periphery of a position disk  31609  that is mounted to the inside surface of the A-side steering handle housing  31024  by threaded fasteners  31606 . When in a depressed state, the cross bar pegs  316041  are moved away from the circumferential slits  31610  until clearance is achieved, and the locking mechanism enables free rotation of the cross bar  31604 , as well as all aspects that are directly connected to the A-side rotatable disk  31607 . Further detail regarding the mechanics behind the locking mechanism can be seen in  FIG. 34 , which is incorporated herein for reference. 
     By way of cross-sectional illustration,  FIGS. 33A-33D  show specific internal features of the devices described herein, and will now be relied upon to reveal further detail.  FIG. 33A  depicts the entire transseptal delivery system  3301  comprised of a distal end  333 , a steerable catheter assembly  3306 , a steering handle  335 , and a delivery handle assembly  334  therebetween the distal end  333  and the proximal end  3302 . At the distal end  333  of the transseptal delivery system  3301  is located the distal  3314  and proximal  3313  capsules, which entrain a prosthetic valve therein. An articulated end  3315  of the steerable catheter assembly  3306  is in mating connection with the distal-most portion of the steering handle  335 , which locates and controls it thereby. The steering thumbwheel  3316  provides actuation control of the articulated end  3315  of the steerable catheter assembly  3306 . Continuing proximally, the delivery handle assembly  334  is depicted, which houses the distal  3311  and proximal  3312  thumbwheels, each being responsible for the translation of the proximal  3313  and distal  3314  capsules, respectively. A hemo port A  3321  is provided and housed by the a-side delivery handle housing  3322  and b-side delivery handle housing  3323  (not shown). Further hemo ports B, C, and D ( 3320 ,  3319 , and  3318  respectively) are also provided, the functions of which being described in greater detail in previous sections. 
       FIG. 33B  introduces a cross-sectional view AA of the aforementioned depiction in  FIG. 33A , which reveals the internal mechanisms of the distal end  333 , the steering handle  335 , and the delivery handle assembly  334 . Cross-section AA of  FIG. 33B  shows the internal surfaces of the distal capsule  3314 , and the proximal capsule  3313 , as well as the articulated end  3315  of the steerable catheter assembly  3306 , all of whose mechanical interactions have been described previously above. Also depicted is an internal view of the steering handle  335 , and the delivery handle assembly  334  which displays the elements distal  3311  and proximal  3312  thumbwheels, and a-side delivery handle housing  3322 . A detail section C  33250  is provided, whereby the enlarged illustration of the contents of detail section C  33250  appear in  FIG. 33C . 
     As mentioned,  FIG. 33C  is the enlarged illustration of the contents of detail section C  33250  of  FIG. 33B , and further detail of the internal features of the valve capsule assembly  3308  are hereby provided. It can be seen that the distal capsule  3314  is internally threaded at a threaded portion  33460 , which provides mating means for a guidewire catheter threaded insert  33490  that is embedded near the distal end  3332  of the guidewire catheter  3230 . Similarly, the bell  3236  is internally threaded at a threaded portion  33470 , which provides mating means for a bell catheter threaded insert  33500  that is embedded near the distal end  33360  of the bell catheter  3234 . Similarly, the anchor  33400  is internally threaded at a threaded portion  33480 , which provides mating means for an anchoring catheter threaded insert  33510  that is embedded near the distal end  3339  of the anchoring catheter  3337 . Further regarding the bell  3236 , it can be seen that the bell  3236  is shown in position and concentrically oriented to the distal most portion  33450  of the anchor  33400 , over which it may translate when actuated accordingly by the delivery handle assembly  334  (not shown). It should be apparent that the connected pair that is comprised of the distal capsule  3314  and guidewire catheter  3230  may move in tandem concentrically within the similarly connected pair that is comprised of the bell  3236  and bell catheter  3234 , which may also move in tandem concentrically within the similarly connected pair that is comprised of the anchor  33400  and anchoring catheter  3237  which are stationary, but inherently flexible by virtue of their construction. The proximal capsule  3313  by way of attachment to the sheath catheter  3241  also form a connected pair that may move in tandem concentrically over the previously discussed catheters. 
       FIG. 33D  depicts the result of the cross-section B-B introduced in  FIG. 33A . As previously described, a plurality of handle housings, A-side  3324  and B-side  3325  are in mated connection and form the entirety of the housing which comprises the steering handle  335 . Within this cross-section B-B of  FIG. 33D  can also be seen a plurality of carrier rods  33601  that matingly pin together the A-side  33607  and B-side  33600  rotatable disks. Also shown are the cross bar  33604 , push-button pin  33611 , and setscrew  33605  that fasten said bar and said pin together in mating connection. The steering thumbwheel  3316 , which houses the push button  33613  and by extension the push button spring  33612  is further revealed, additionally. 
       FIGS. 34A-34C  illustrate the internal mechanics of the locking mechanism that is inherent to the steering handle  335  (of which these figures provide a cross-sectional view), and further illustrate the dynamic relationships between the components, and the manner in which they may be operated. Beginning with  FIG. 34A , the sequence of operation that comprises pushing a button, turning a knob, and then releasing the button while maintaining an achieved angular position by the button is set forth. Specifically,  FIG. 34A  depicts the depression (arrow indicating translation  34700 ) of the push button  34613  that is mounted within the steering thumbwheel  3416  and biased internally by the opposing force of the push button spring  34612 . As the push button  34613  is matingly connected to the cross bar  34604  by way of the push button pin  34611  and the setscrew  34605 , when the push button  34613  is translated through depression, the cross bar  34604  is also translated (arrows indicating translation  34730 ) in the same direction as the push button  34613 . Once the cross bar  34604  is fully translated, a plurality of cross bar pegs  346041  described on the ends of the cross bar  34604  become disengaged from circumferential slits  34610  ( FIG. 34B ) that are provided by the position disk  34609  ( FIG. 34B ). 
     Continuing within  FIG. 34B , once the cross bar  34604  is unconstrained it is thus free to rotate (arrows indicating rotation  34740 ) by the application of a torque to the steering thumbwheel  3416  (arrows indicating rotation  34710 ). 
       FIG. 34C  provides the final step in the operation of the push button  34613  mechanism of the steering thumbwheel  3416  for steering and positional lockout. After the appropriate rotational position is achieved with the steering thumbwheel  3416 , the push button  34613  is released. This allows for translation in the opposite direction (arrows indicating translation  34720 ) to that experienced when the push button  34613  is depressed, due to the biasing force of the push button spring  34612 . Releasing the push button  34613  also allows the cross bar  34604  to translate (arrows indicating translation  34750 ) and by extension, the cross bar pegs  346041  may thus achieve re-engagement with the circumferential slits  34610  ( FIG. 9B ) and provide lockout against further rotation of the steering thumbwheel  3416  and by extension disruption of position of the steerable catheter  34309  (not shown). 
     Turning now to  FIGS. 35A-35D , a sequence of images is provided which depict the rotation of the steering thumbwheel  3516  and the ensuing effect at the valve capsule end of the system. Beginning with  FIG. 35A , when a torque is applied to the steering thumbwheel  3516 , rotational motion is transferred to the A-side rotatable disk  35607 , which is in communication with a plurality of pull wires  35308  that are further internally embedded at the articulated end  3515  of the steerable catheter assembly  356 . The pull wires act to preferentially pull the articulated end  3515  of the steerable catheter assembly  356  in the direction of steering thumbwheel  3516  rotation. Further application of torque ( FIG. 35B-35D ) results in a further rotation of the steering thumbwheel  3516  and yet further bending of the articulated end  3515  of the steerable catheter assembly  3106 . 
     Now with specific reference to  FIGS. 36A-36D , a particular example of a valve capsule assembly  3608 , and general deployment sequence of a transcatheter valve prosthesis are herein illustrated. Details regarding the transcatheter valve prosthesis referenced herein may be any of the prostheses disclosed herein and are described in commonly owned U.S. Pat. No. 8,579,964 to Lane et. al. As depicted in  FIG. 36B , a transcatheter valve prosthesis  361100  is entrained within the valve capsule assembly  3608 , after having been preferentially crimped (details regarding the loading device used to crimp the transcatheter valve prosthetic are described in commonly owned U.S. Pat. Publication. No. 2014/0155990, the entire contents of which are incorporated herein by reference, and loaded therein. The valve capsule assembly  3608  can comprise a generally cylindrical structure having a proximal end and a distal end, wherein each of the proximal and distal ends terminates in a rounded dome-like surface. As shown in  FIGS. 36A , the valve capsule assembly can comprise a proximal capsule  3613  and a distal capsule  3614 , wherein the proximal capsule  3613  is disposed at a proximal end of the valve capsule assembly, and the distal capsule  3614  is disposed at a distal end of the valve capsule assembly. Each of the proximal capsule  3613  and the distal capsule  3614  can have a cylindrical portion with one end of the cylindrical portion having an open circular shape and the other end having a cap portion that can have a rounded dome-like surface. As shown in  FIG. 36B , the open circular shape of proximal capsule  3613  can be configured to meet with or abut against the open circular shape of distal capsule  3614 , with the cap portion of the proximal capsule forming the proximal end of the valve capsule assembly, and the cap portion of the distal capsule forming the distal end of the valve capsule assembly. 
       FIG. 36C  illustrates the valve  361100  in staged deployment after the proximal capsule  3613  has been translated away from the valve  361100 , and the atrial skirt  361101  has been revealed and allowed to self-expand. 
       FIG. 36D  illustrates the valve  361100  with the atrial skirt  361101  fully expanded, after the distal capsule  3614  has been translated away from the valve  361100 . A plurality of trigonal anchoring tabs  361102  have also been revealed by the movement of the distal capsule  3614 . 
       FIG. 36E  illustrates final deployment of the valve  361100 , whereby the distal capsule  3614  has translated to its maximum displacement, and the bell  3636  on the bell catheter has also translated maximally in order to release anchoring features of the valve (not shown) until finally full release of the valve from the delivery device has been achieved, and the valve  361100  is no longer anchored to any part of the valve capsule assembly  3608 . 
     User Interface Stops 
     In some situations, it may be desirable to provide user interface stops on the delivery system so that the operator does not inadvertently deploy the prosthesis prematurely. Various stopping mechanisms may be incorporated into the delivery system. 
     A first stopping mechanism may be included in the delivery system to prevent the operator from inadvertently releasing the elbows on a prosthetic mitral valve. The elbows are the inferior portion of the ventricular anchor tabs adjacent to the connection point of the ventricular anchor tab with the ventricular skirt. In any of the delivery systems disclosed herein, an outer sheath is retracted from the prosthesis and the superior tips of the ventricular anchor tabs (anterior and posterior) initially self-expand radially outward and in a transverse position relative to the longitudinal axis of the prosthesis. The transverse position is horizontal or nearly horizontal relative to the longitudinal axis of the prosthesis. With further retraction of the sheath, the elbows become unconstrained and the ventricular anchor tabs spring fully open and the tab returns to an inferior/superior orientation that is substantially vertical or substantially parallel to the longitudinal axis of the prosthesis. Once the elbow is unconstrained, it is challenging and may not be possible to resheath and recover the ventricular anchor tabs in case they were improperly deployed. Also once the ventricular anchor tabs are released and fully deployed it becomes challenging or may no longer be possible to resheath the remainder of the prosthesis in case delivery needs to be aborted or the prosthesis requires repositioning. 
       FIGS. 37A-37I  disclose a hard stop mechanism that may be included on any of the delivery system handles disclosed herein, or elsewhere to prevent the operator from inadvertently retracting the sheath far enough to fully release the elbows. As the operator retracts the sheath, the hard stop will prevent further retraction until the operator actuates a release mechanism such as a button, switch or other mechanism to allow further retraction of the sheath and eventual release of the elbows. Thus, once the operator is confident that he/she is ready to fully release the ventricular anchor tabs, the release mechanism may be actuated thereby allowing the operator to continue retracting the outer sheath and releasing the elbows on the ventricular anchor tabs. 
     Optionally, a second stop may also be included in any of the delivery systems disclosed herein. Again, operation of delivery systems allow the operator to continue to deploy the prosthesis. After deployment of the ventricular anchors, further deployment allows the operator to retract the bell catheter which then removes a constraint from the commissure tabs thereby allowing the commissure tabs to uncoupled from the hub catheter slots and then the prosthesis is fully uncoupled from the delivery catheter. At this point it is challenging or may not be possible to retrieve the commissure tabs or the prosthesis if needed. The second stop therefore similarly prevents the operator from releasing the commissure tabs before the operator is certain that he/she wishes to proceed and this may help prosthesis retrieval or resheathing if needed. 
     The second stop may be any number of stop mechanisms which can be actuated to allow the operator to proceed with release of the commissure tabs. The stop mechanism may be a button, switch or any other mechanism. 
       FIG. 37A  shows a handle  3702  of a delivery system that may be the handle in any delivery system disclosed herein. The handle  3702  includes one or both hard stops  3704 ,  3706  which each have a locked position and an unlocked position. Here, both hard stops or switches  3704 ,  3706  are in the down or locked position which will prevent certain actuation of the handle. 
       FIG. 37B  shows a partial cutaway of the handle  3702  in  FIG. 37A . Here, similar as to the other delivery mechanisms disclosed herein, a lead screw  3720  is actuated by rotation of a wheel or knob  3722  such that rotation of wheel  3722  is translated into axial movement of lead screw  3720  to move the various shafts as described previously. The lead screw is contoured to have a flat surface  3716  and a rounded surface  3718 . Two blocks  3708  and  3710  are actuated by movement of switches  3704 ,  3706  to allow or prevent motion. Here, both blocks  3708 ,  3710  also have a rounded interior surface  3714  and a flat surface  3712  to match the rounded and flat surfaces  3718 ,  3716  on the lead screw. However, when the switches  3704 ,  3706  are in the locked position, the rounded and flat surfaces of the blocks are not registered with the rounded and flat surfaces of the lead screw and thus the lead screw will be unable to move through and past either block  3708 ,  3710 . However, rotation of wheel  3722  will retract the lead screw proximally until the proximal end of the lead screw abuts the distal end of block  3708 . This motion is enough to allow the atrial flange on the prosthesis to deploy as described previously. 
       FIG. 37C  shows the lead screw  3720  proximally retracted until its proximal end abuts the distal end of block  3708  and stops, thereby retracting the outer sheath and allowing the atrial flange to deploy on the prosthesis. 
     In  FIG. 37D  switch  3704  is flipped to the unlocked position while switch  3706  remains in the locked position. 
       FIG. 37E  shows the flat and rounded portions  3716 ,  3718  of the lead screw  3720  aligned with the flat and rounded portions  3714 ,  3712  on the distal block  3708  so that the rotation of wheel  3722  retracts the lead screw further into block  3708 . 
       FIG. 37F  shows the lead screw fully retracted until the proximal end of the lead screw abuts the distal end of block  3710  which is not registered with the lead screw since the switch is in the locked position. This further retracts the sheath and deploys the prosthesis. Here the annular region and ventricular skirt region deploy as well as the ventricular anchor tabs partially deploy. 
     In  FIG. 37G  both switches  3704 ,  3706  are now disposed in the unlocked position. 
     In  FIG. 37H  rotation of wheel  3722  continues to move the lead screw into block  3710  further retracting the sheath and releasing the elbows of the anchor tabs and allowing them to fully deploy. 
     In  FIG. 37I , the lead screw  3720  passes through block  3710  and pushes the bell slider  3724  back proximally until it abuts against a stop wall  3726 . At this point the sheath is fully retracted and the bell catheter is fully retracted thereby allowing the prosthesis to fully release from the delivery catheter as the commissure tabs release from slots in the hub or anchor element. 
     Optionally in any example, the delivery system may include a third or more stops. For example, the first stop may be used to control deployment of one or both anterior ventricular anchor tabs, a second stop may be used to control deployment of the posterior ventricular anchor tab, and a third stop may be used to control deployment of the commissure tabs. In another example, a first stop may be used to control deployment of one anterior ventricular anchor tab, a second stop may be used to control deployment of a second anterior ventricular anchor tab, a third stop may be used to control deployment of the posterior anchor tab, and a fourth stop may be used to control deployment of the commissures. Optionally, in any example, there may be a hard stop on other stages of prosthesis deployment, such as during the initial deployment of the atrial skirt. The optional hard stop may be any of the mechanisms disclosed herein or otherwise known in the art. Therefore any number of stops may be used to control deployment of any of the various portions of the prosthesis. 
     Retrievability 
     In some circumstances is may be desirable to retrieve the prosthesis from a partially or fully deployed state in order to adjust position of the prosthesis, abandon the procedure, or for other reasons. 
     The retrieval mechanisms allow the operator to fully recapture the prosthesis after the elbows have been deployed and prior to release of the commissure tabs. Control cables or tethers may be disposed in the delivery system handle and allow individual tensioning of each elbow. The control cables or tethers may be coupled directly to the prosthesis or to a deployment control mechanism operably coupled to one or more of the elbows in the prosthesis. The deployment control mechanism may be used to control deployment of the elbow and retrieval of the prosthesis. In other examples, a catheter may be used that has attachments to the tethers at the very distal end of the delivery system. The tensioning can be individual or group controlled depending on the mechanism and desired behavior. 
     Tension may be adjusted individually, or in unison. The tension control cables also may allow tension control in the crescents in unison. The crescents are portions of the ventricular skirt on the prosthesis frame just superior to the commissure tabs. 
     In one example, upon deployment of the prosthesis, no other materials other than the prosthesis are left behind in the patient. Any of the examples disclosed herein may be used with the transapical or transseptal delivery systems disclosed herein. 
     The cables or tethers may be a single filament (three for the elbows, and three for the crescents), or the cables maybe comprise two filaments for each elbow and each crescent, where the two filaments are formed from a single filament looped around the elbow or crescent allowing them to be removed post implant or to tack them at the apex of the heart if required by retracting one of the free ends of the filament. Any of the tethers disclosed herein may also be a single filament with a closed loop. Both strands in the closed loop pass through the elbow and attach to the post or tab on the anchor element. When the capsule is deployed and the loop is allowed off the post, then the whole closed loop pulls back through the elbows and the loop is retracted into the delivery system. 
     In another example, the tethers may remain attached to the prosthesis thereby providing another opportunity for the tethers to be manipulated. For example, in the situation when the prosthesis has not been properly deployed and retrieval was not successful, the tethers may still be anchored at the location where the delivery device was inserted into the heart, thereby providing supplemental anchoring of the prosthesis. Therefore, some or all of the tethers may be removed from the prosthesis or some or all of the tethers may remain connected to the prosthesis after delivery and deployment. 
       FIGS. 38A-38C  illustrate an example that uses tethers to control prosthesis deployment. 
     In  FIG. 38A  the prosthesis  3802  is partially deployed as previously described above with the atrial flange, annular region and ventricular anchors  3804  (anterior and posterior) partially deployed. The elbows  3806  of the ventricular anchors are still partially constrained by the distal capsule  3808 . 
     In  FIG. 38B  the elbows  3812  are released from the distal capsule and allowed to spring fully open into a substantially vertical configuration. Tethers  3810  remain coupled to the elbows, thus if needed tension may be applied to the tethers to collapse and recapture the elbows so that the entire prosthesis may be recaptured in the sheath/capsules and then either repositioned and redeployed, or the procedure may be abandoned and the catheter with prosthesis withdrawn from the patient. The tethers may be suture material, wires, or other elongate filaments than span the length of the catheter and can be controlled at the proximal end of the delivery device from the handle or any other tether control mechanism. Additionally, when the elbows are disposed in the capsule, the capsule helps prevent release of the tethers from the elbows. 
       FIG. 38C  shows release of the tethers  3810  from the elbows after the prosthesis is properly positioned and then the commissure tabs may be released from the anchor hub. The tethers may be retracted from the patient at the same time the catheter is withdrawn from the patient, or the tethers may be retracted first independently of catheter withdrawal. Here, three tethers are used, one for the two anterior anchors and one for the posterior anchor. The filament may form a large elongate loop and one free end of the tether may be released allowing the filament to be pulled through the elbow and back out the proximal end of the catheter thereby releasing the filament from the prosthesis. Or, tension may be released from the tether allowing the elbows to spring open and release from the looped part of the filament. 
     Moreover, using tethers coupled to the elbows allows the sequence of deployment of the elbows to be controlled by controlling tension on the tethers. For example, all elbows maybe deployed simultaneously, or they may be deployed in a desired sequence. For example, both anterior elbows maybe deployed first simultaneously followed by the posterior elbow. Or the posterior elbow may be deployed first, followed the anterior elbows either both together or one after the other. Or, one anterior elbow may be deployed first, followed by the second anterior elbow, followed by the posterior elbow. Or one anterior elbow may deploy first followed by the posterior elbow followed by the other anterior elbow. Or all three elbows may be deployed simultaneously. 
     In addition to tethers such as sutures, elongate wire filaments may be used to control prosthesis deployment and recapture. For example, in  FIG. 39A , three elongate wires  3902  (also referred to as stylets) with looped ends  3904  may extend the length of the catheter and the looped ends  3904  may be coupled to the elbows. Or, the elongate wires may be used and the looped ends  3904  may be coupled to a suture or other filament that is coupled to the elbows. Using elongate suture running the length of the catheter can create significant friction which may make it difficult to manipulate the suture tethers and thus a partial suture and part wire tether may reduce friction and create a more optimal tether. 
     The elongate wires may extend from an internal catheter running a short distance, most of the distance, or the entire distance of the delivery system to further reduce friction. Or, in other examples the suture may be attached directly to an attachment element on an elbow control catheter. 
       FIG. 39C  illustrates an example of sytlets  3910  with looped ends  3918  are coupled to suture filaments  3920 . The suture filaments  3920  are looped  3922  around the tabs or posts  3924  on the anchor element to constrain and control an elbow. An optional anchor plate  3926  may also be used and additional disclosure about this element is provided below. A cable guard  3916  having several channels or lumens  3914  extending through the cable guard allow the filaments and/or sytlets to pass through the cable guard which ensures there is no entanglement and also helps to minimize friction. The cable guard  3916  may be disposed over the anchor catheter  3912 . 
       FIG. 39B  shows the tethers are flexible and can bend with the catheter during delivery or during steering. 
     Equal adjustment of tension in tethers may be desirable in order to control deployment or control recapture of the prosthesis.  FIG. 40  shows an example of a tension equalizer that may be used with any example of delivery system disclosed herein. 
     In  FIG. 40 , the plurality of tethers  4002  are coupled to the anchor element (sometimes also referred to herein as a hub) and then the anchor elbows are coupled to the looped ends of the tethers. And optional anchor plate is coupled to the anchor. This will be described in greater detail below. The tethers may extend along the length of the delivery catheter and converge to a single point  4004  on a proximal portion of the delivery catheter, often in the handle. A tension control mechanism  4006 , here a screw winds the tethers around a shaft increasing tension unwinds the tethers from the shaft, decreasing tension. This helps ensure that a uniform tension is applied to each tether. 
     Optionally, in any example, the hub or anchor element may be modified as shown in  FIGS. 41A-41B  to facilitate capture and release of the commissures as well as the tethers. 
       FIG. 41A  shows the anchor element  4112  (also referred to as a hub) which may be used in any delivery catheter. It is a generally disc-shaped element having a plurality of slanted tabs  4104  that extend radially outward. Additionally, there are slots  4106  which are also slanted. An optional anchor plate  4108  with radially extending arms  4110  that cooperate with the tabs  4104 . A push rod  4102  is coupled to the anchor plate. 
     The tabs and the slots are sloped or slanted downward in the distal direction so that the commissure tabs can easily slide off and disengage from the slots, and similarly so that the looped ends of the tethers can also release from the tabbed regions. 
     In use, tension is applied to the push rod so that the anchor plate abuts the anchor element and the arms  4110  cooperate with the tabs  4104  to help capture the tethers therebetween, and when the operator wishes to release the tethers, the push rod maybe pushed distally to move the anchor plate away from the anchor element increasing the gap between the arms  4110  and the tabs  4104  to allow the looped ends of the tether to release. In other examples, a small gap remains from between the arms and the tabs and the tether may simply pass through the gap automatically when tension on the tethers is released, therefore the push rod is optional. 
       FIG. 41B  shows the anchor plate  4108  disengaged from the anchor element when the push rod is pushed distally. The push rod may extend along the length of the catheter to the proximal end of the device and it may be actuated by a control on the handle. As discussed previously, the handle may include a hard stop such as those previously discussed above to lock or unlock a control that allows actuation of the push rod or any mechanism that controls engagement of the anchor plate with the anchor. 
     Optionally in any example with an anchor plate (sometimes also referred to as an elbow retention plate or J-plate) a passive release mechanism includes a spring element that biases the anchor plate against the anchor to hold the filament loops. When the prosthesis self-expands the spring force of the expanding prosthesis overcomes the spring force holding the anchor plate against the anchor and pulls the filament loops out from the anchor permitting release of the elbows. This is in contrast to the active release mechanism in  FIG. 41B  which uses a push rod. 
     Soft Edge 
     A soft edge on the delivery catheter helps minimize tissue trauma and this element may also help facilitate management of the large number of catheter shafts, tethers, wires, or other tubes and rods which may be used in a delivery system. 
       FIG. 42  shows an example of a soft edge  4202 . It may be attached to the centering catheter and provides a soft edge proximal to the capsule/prosthetic valve on the end of the delivery system. This aids in valve retrievability by minimizing risk of damage to patient anatomy. 
     It is a round disc-like resilient component with a plurality of through holes  4208  that allow the disc to be compressed to a smaller outer diameter since the disc may be larger than the inner diameter of the capsule so it needs to be compressible in order to fit in the capsule. Oversizing the disc accounts for any deformation/flaring of the capsule during tracking, deployment, or resheathing. Both the proximal and distal ends  4204 ,  4206  are beveled or angled to help center components which interact with the soft edge  4202  and also to facilitate smooth passage of the delivery device thorough a vessel or other anatomy. A central channel  4210  may be formed to allow tethers, or other catheter shafts to pass through the soft edge element. For example, here the central channel is cross shaped with discrete slots separated from one another and sized to accommodate the anchor catheter and any tethers. The soft edge may be disposed over the anchor catheter and may be disposed axially proximal of the capsule that houses the prosthesis. However, this is not limiting and it maybe disposed anywhere along the delivery catheter as desired. The soft edge may be coupled to the next adjacent shaft that is over the anchor catheter. 
     Other management elements similar to the tether management element may also be used. For example, an annular ring with a plurality of slots on an inner diameter of the ring maybe adjacent of and on a proximal end of the anchor element. Tethers or wires may pass through the annular ring in the slotted regions and this helps prevent entanglement. This element is not illustrated due to its simplicity. 
     Optional Features 
     Any of the delivery systems disclosed herein may also include any of the following optional features. 
     As previously discussed, the commissures are anchored to slots in an anchor element or hub. When a constraint is release, the commissures are free to expand and release from the slots. Optionally in any example, an O-ring or other resilient member may be disposed around the circumference of the anchor element between the commissures and the anchor element so that when the bell element is disposed over the commissures and constrains the commissures, the O-ring will compress. When the bell is removed from the commissures, the commissures will expand out of the slots aided by the resilient O-ring also expanding. Therefore the O-ring helps facilitate release of the commissures from the anchor element. 
     The anchor catheter may also have an optional steering mechanism. Any of the tethers coupled to the anchor element to control the anchor elbows or additional tethers may be coupled to the anchor element and when tension is applied to those anchors, they will bend or steer the anchor catheter. Opposite tethers may be used to steer the anchor catheter in one direction or the opposite direction depending on which tether is tensioned. Any number of tethers may be used to steer the anchor catheter in any number of directions. 
     Any example of delivery catheter may also include additional cable organizer elements. For example one, two, three, or more cylindrical elements may be disposed along the anchor catheter with slots, channels or though holes to allow tethers, wires, stylets, or any other filaments to pass through. This keeps the filaments extending in a linear untangled manner along the length of the catheter proximally toward the handle. 
     NOTES AND EXAMPLES 
     The following, non-limiting examples, detail certain aspects of the present subject matter to solve the challenges and provide the benefits discussed herein, among others. 
     Example 1 is a prosthetic delivery system comprising a delivery catheter having a plurality of concentric shafts; an actuator mechanism coupled to one or more of the plurality of concentric shafts, wherein actuation of the actuator mechanism advances or retracts the one or more of the plurality of concentric shafts; and a first stop mechanism operably coupled to the actuation mechanism, wherein the stop mechanism prevents advancement or retraction of the one or more of the plurality of concentric shafts beyond a predetermined position unless the stop mechanism is released thereby allowing full advancement or retraction of the one or more of the plurality of concentric shafts. 
     Example 2 is the delivery system of Example 1, further comprising a second stop mechanism operably coupled to the actuation mechanism, wherein the second stop mechanism prevents advancement or retraction of another of the plurality of concentric shafts beyond a predetermined position unless the second stop mechanism is released thereby allowing full advancement or retraction of the another of the plurality of concentric shafts. 
     Example 3 is any of the delivery systems of Examples 1-2, further comprising a second stop mechanism, wherein the first stop mechanism controls deployment of a first anterior anchor tab on the prosthesis, and wherein the second stop mechanism controls deployment of either a second anterior anchor tab or a posterior anchor tab on the prosthesis. 
     Example 4 is any of the delivery systems of Examples 1-3, wherein the stop mechanism comprises a block having an inner channel shaped to receive a lead screw in a handle of the delivery system, wherein the stop mechanism rotates the block in a first direction so that the inner channel is misaligned with the lead screw in a first position to prevent movement of the lead screw through the channel, and wherein the stop mechanism rotates the block in a second direction opposite the first direction so that the inner channel is registered with the lead screw allowing movement of the lead screw through the channel. 
     Example 5 is a prosthetic delivery system comprising a delivery catheter having a plurality of concentric shafts; a capsule having a proximal end and a distal end, the capsule sized to hold a prosthesis and operably coupled to at least one of the plurality of shafts; and a chamfer element having a proximal beveled end and a distal beveled end, the distal beveled end engageable with the proximal end of the capsule to provide smooth transition between the capsule and an adjacent shaft, the proximal and distal bevels also configured to center the capsule when engaged therewith or to center at least some of the plurality of concentric shafts when engaged therewith, and wherein the proximal and distal beveled ends are configured to minimize or prevent trauma to tissue as the delivery catheter is advanced or retraced. 
     Example 6 is the delivery system of Example 5, wherein the chamfer element comprises a plurality of apertures disposed around a perimeter of the chamfer element, the plurality of apertures configured to allow compression and expansion of the chamfer element. 
     Example 7 is any of the delivery systems of Examples 5-6, wherein the chamfer element comprises an aperture extending through a central portion of the chamfer element, the aperture configured to permit one or more of the plurality of concentric shafts to slidably pass through the aperture, or wherein the aperture is configured to permit one or more tethers to slidably pass through the aperture. 
     Example 8 is a prosthetic delivery system comprising a delivery catheter having a plurality of concentric shafts, wherein the plurality of concentric shafts comprises an anchor catheter having an anchor element adjacent a distal end thereof, the anchor element configured to engage and hold anchors on a prosthesis. 
     Example 9 is the delivery system of Example 8, wherein the anchor element comprises a plurality of tether pegs configured to engage and hold one or more tethers. 
     Example 10 is any of the delivery systems of Examples 8-9, wherein the anchor element comprises a plurality of slots configured to receive the anchors on the prosthesis. 
     Example 11 is any of the delivery systems of Examples 8-10, wherein a surface surrounding at least some of the plurality of slots is inclined to facilitate release of the anchors on the prosthesis from the plurality of slots. 
     Example 12 is any of the delivery systems of Examples 8-11, further comprising an anchor shaft guide element proximal of the anchor element, the anchor shaft guide comprising a plurality of internal slots on an inner perimeter of the anchor shaft guide, the plurality of internal slots configured to receive tethers. 
     Example 13 is any of the delivery systems of Examples 8-12, wherein the anchor element comprises a resilient material configured to expand and contract, wherein in the expanded configuration, the anchors on the prosthesis are pushed radially outward away from the slots. 
     Example 14 is any of the delivery systems of Examples 8-13, further comprising one or more steering tethers coupled to the anchor element, wherein tension applied to the steering tethers steers the anchor catheter. 
     Example 15 is any of the delivery systems of Examples 8-14, further comprising a plurality of tethers coupled to the anchor element and the anchors on the prosthesis, the plurality of tethers configured to control deployment of one or more elbow regions on the anchors of the prosthesis. 
     Example 16 is any of the delivery systems of Examples 8-15, further comprising a capsule and a plurality of tethers, the capsule coupled to at least one of the plurality of concentric shafts and configured to carry the prosthesis, wherein the plurality of tethers are configured to control deployment of one or more elbow regions on the anchors of the prosthesis, and wherein the capsule constrains release of the plurality of tethers from the anchor when the anchor is disposed in the capsule. 
     Example 17 is any of the delivery systems of Examples 8-16, further comprising a plurality of tethers releasably coupled to a plurality of elbow regions on the anchors of the prosthesis, and wherein actuation of the plurality of tethers controls displacement of the plurality of elbow regions. 
     Example 18 is any of the delivery systems of Examples 8-17, further comprising a stylet coupled to at least some of the plurality of tethers. 
     Example 19 is any of the delivery systems of Examples 8-18, wherein the anchors on the prosthesis are configured to reengage with the anchor element when tension is applied to the plurality of tethers after the anchors on the prosthesis are radially expanded outward. 
     Example 20 is any of the delivery systems in Examples 8-19, further comprising a guide element coupled to the anchor catheter and disposed proximal of the anchor element, the guide element having a plurality of slots therein or channels therethrough, the plurality of slots or channels configures to guide wires, filaments, stylets passing therethrough. 
     Example 21 is any of the delivery systems in Examples 8-20, further comprising a plurality of tethers coupled to the anchors of the prosthesis to hold the prosthesis, wherein the plurality of tethers converge together onto a tension equalizer element configured to apply equal tension to each of the plurality of tethers. 
     Example 22 is any of the delivery systems in Examples 8-21, further comprising an elbow retention plate adjacent the anchor element. 
     Example 23 is a method of delivering a prosthesis, said method comprising advancing a delivery catheter carrying a prosthesis to a target treatment area; actuating an actuator on the delivery catheter to advance or retract a shaft in the delivery catheter thereby removing a constraint from the prosthesis until a stop mechanism in the delivery catheter prevents further advancement or retraction of the shaft beyond a predetermined position; and releasing the stop mechanism thereby allowing further advancement or retraction of the shaft beyond the predetermined position. 
     Example 24 is the method of Example 23, further comprising: further actuating the actuator to advance or retract a second shaft in the delivery catheter thereby removing a second constraint from the prosthesis until a second stop mechanism in the delivery catheter prevents further advancement or retraction of the second shaft beyond a second predetermined position; and releasing the second stop mechanism thereby allowing further advancement or retraction of the second shaft beyond the second predetermined position. 
     Example 25 is the method of any of Examples 23-24, wherein the delivery catheter further comprises a second stop mechanism, the method further comprising wherein releasing the stop mechanism and further movement of the shaft removes a constraint from the prosthesis thereby allowing radial expansion of a first ventricular anchor tab on the prosthesis; and wherein releasing the second stop mechanism allows radial expansion of a second ventricular anchor tab or a posterior anchor tab on the prosthesis. 
     Example 26 is a method for delivering a prosthesis, said method comprising providing a prosthesis carried on a delivery catheter; at least partially deploying the prosthesis from the delivery catheter; and retrieving the prosthesis back into the delivery catheter by actuating a plurality of filaments coupled to the prosthesis. 
     Example 27 is the method of Example 26, further comprising steering the delivery catheter by actuating a tether coupled to the delivery catheter. 
     In Example 28, the apparatuses or methods of any one or any combination of Examples 1-27 can optionally be configured such that all elements or options recited are available to use or selection from. 
     The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein. 
     In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls. 
     In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. 
     The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.