Abstract:
Heart valve delivery systems and methods of delivering and implanting heart valves using delivery catheters are disclosed. The delivery systems can include a handle assembly which can include a first control mechanism, a second control mechanism, and a decoupling mechanism. The delivery systems can also include a delivery catheter extending from the handle assembly. The delivery catheter can include an outer shaft, which can be controlled by the first control mechanism; a prosthesis containing capsule comprising a proximal capsule portion connected to the outer shaft, and a distal capsule portion releasably coupled to the proximal capsule portion. After deploying a valve prosthesis, the capsule can be closed by activating the decoupling mechanism in the handle to rapidly close the distal and proximal capsule portions together. The delivery system can also include a centering element to guide the distal and proximal capsule portions together.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The present disclosure relates to systems for delivering a prosthesis to a desired location in the body of a patient and methods for delivering and implanting a prosthesis. More particularly, the present disclosure relates to prosthetic valve delivery systems for deploying a heart valve prosthesis within a body lumen and to methods of delivering such a prosthesis to a desired location in the body. 
         [0003]    2. Background 
         [0004]    Currently, replacement of a deficient cardiac valve is often performed by placing the patient under extracorporeal circulation, temporarily stopping the heart, opening the thorax (e.g., by a sternotomy), surgically opening the heart, excising the deficient valve, and then implanting a prosthetic valve in its place. This procedure generally requires prolonged patient hospitalization, as well as extensive and often painful recovery. 
         [0005]    Recently, minimally invasive approaches have been developed to facilitate catheter-based implantation of valve prostheses in the beating heart, intending to obviate the need for the classic sternotomy and cardiopulmonary bypass. For example, U.S. Pat. No. 8,016,877 to Seguin et al. illustrates a technique and a device for replacing a deficient heart valve by percutaneous route. An expandable prosthetic valve can be compressed about a catheter, inserted inside a body lumen, such as the femoral artery, and delivered to a desired location in the heart. Additionally, U.S. Pat. No. 7,914,569 to Nguyen et al. discloses advancing a catheter containing a prosthesis in a retrograde manner through the femoral artery and into the descending aorta, over the aortic arch, through the ascending aorta and inside the defective aortic valve. This procedure can be assisted by fluoroscopic guidance. Once the position of the catheter containing the prosthesis is confirmed, a sheath containing the prosthesis can be moved proximally, allowing the valve prosthesis to self-expand. 
         [0006]    Other techniques for delivering prosthetic heart valves via a catheter include transapical and trans-aortic approaches for aortic valve replacement, typically involving the use of an introducer port, i.e., a large-bore overtube, of a trocar. A crimped, framed valve prosthesis reversibly coupled to a delivery catheter can be transcatheterally advanced toward the native valve, where it can either be deployed using a balloon catheter, or, alternatively, using a self-expandable system. 
         [0007]    With regard to the structure of the heart valve prosthesis itself, U.S. Pat. No. 7,914,569 to Nguyen et al. describes an example prosthesis for percutaneous transluminal delivery, and is incorporated by reference herein in its entirety. The heart valve prosthesis can have a self-expanding multi-level frame that supports a valve body with a skirt and plurality of leaflets. The frame can be contracted during percutaneous transluminal delivery and expanded to an hourglass shape upon deployment within the native heart valve. 
       BRIEF SUMMARY 
       [0008]    The present disclosure describes delivery systems for implanting a heart valve prosthesis through a trans-aortic pathway. By directly accessing the aorta, it is possible to accurately implant a prosthetic valve without the need for cardiopulmonary bypass, although the disclosed delivery systems can also be used with cardiopulmonary bypass. Furthermore, the delivery systems disclosed herein can allow for quick and accurate retraction of a distal portion of the capsule member used to contain the valve prosthesis. It is understood that while the disclosure refers specifically to a trans-aortic procedure, the delivery systems and methods disclosed herein can also be used for any access route, vessel or location within the heart and vasculature. 
         [0009]    In certain embodiments, the delivery systems can include a handle assembly which can include a first control mechanism, a second control mechanism, and a decoupling mechanism. The delivery systems can also include a delivery catheter extending from the handle assembly. The delivery catheter can include an outer shaft, which can be controlled by the first control mechanism, and a prosthesis containing capsule comprising a proximal capsule portion connected to the outer shaft and a distal capsule portion releasably coupled to the proximal capsule portion. The capsule can also include a distal tip and a prosthesis containment sleeve. The delivery catheter can also include an intermediate shaft having a prosthesis retainer located at its distal end, and an inner shaft which can be controlled by the second control mechanism and can be connected to the distal capsule portion. In certain embodiments, the delivery system can also include a safety mechanism, which can be connected to the first control mechanism, and configured to prevent proximal retraction of the outer shaft beyond a predetermined distance. In certain embodiments, the delivery system can also include a capsule centering element such as, but not limited to, a self-expanding frame, a self-expanding funnel, or a centering shaft. 
         [0010]    Also disclosed herein are catheter tips, which can include a proximal capsule portion and a distal capsule portion releasably coupled to the proximal capsule portion. The distal capsule portion can include a distal tip, connected to an inner shaft of the catheter, and a prosthesis containment sleeve. The catheter tip can also include an intermediate shaft having a prosthesis retainer located at a distal end. In certain embodiments, the catheter tip can include a centering shaft having a tapered distal nose and configured to move axially along the intermediate shaft. In certain embodiments the catheter tip can include a capsule centering element attached to the intermediate shaft, located proximally from the prosthesis retainer and configured to guide the distal capsule portion and the proximal capsule portion back together after separating to deploy the valve prosthesis. 
         [0011]    In order to deliver the prosthesis, the delivery system can be introduced into a patient&#39;s aorta and the delivery catheter can be advanced within the aorta to a deployment location. The first control mechanism can be activated to proximally retract the outer shaft and proximal capsule portion, and the second control mechanism can be activated to distally advance the distal capsule portion to release the valve prosthesis. The capsule can be closed by activating a decoupling mechanism to close the distal capsule portion and proximal capsule portion together. The delivery system can then be retracted proximally through the deployed valve prosthesis and removed from the body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The accompanying figures, which are incorporated herein, form part of the specification and illustrate embodiments of prosthetic valve delivery systems and methods of delivering a valve prosthesis to a desired location in a body of a patient. Together with the description, the figures further serve to explain the principles of and allow for the making and using of the prosthetic valve delivery systems and methods described herein. These figures are intended to be illustrative, not limiting. Although the disclosure is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the disclosure to these particular embodiments. In the drawings, like reference numbers indicate identical or functionally similar elements. 
           [0013]      FIG. 1  illustrates a delivery system, according to an embodiment. 
           [0014]      FIG. 2A  shows a close-up view of the handle, according to an embodiment. 
           [0015]      FIG. 2B  shows a close-up view of the front grip, according to an embodiment. 
           [0016]      FIG. 2C  shows a close-up view of the rear grip, according to an embodiment. 
           [0017]      FIGS. 3A-3D  illustrate the valve deployment sequence, according to an embodiment. 
           [0018]      FIGS. 4A-4B  illustrate an interior view of the handle, according to an embodiment. 
           [0019]      FIG. 5A  illustrates a partial interior view of the housing for the decoupling mechanism, according to an embodiment. 
           [0020]      FIG. 5B  illustrates the handle after being decoupled, according to an embodiment. 
           [0021]      FIGS. 6A-6C  illustrate close-up views of the valve retainer, according to certain embodiments. 
           [0022]      FIGS. 7A-7B  illustrate the centering frame attached to the delivery system and separately, according to an embodiment. 
           [0023]      FIGS. 8A-8B  illustrate the centering funnel attached to the delivery system and separately, according to an embodiment. 
           [0024]      FIGS. 9A-9B  illustrate the centering shaft, according to an embodiment. 
           [0025]      FIGS. 10A-10B  illustrate the centering shaft including a centering dome, according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    While the disclosure refers to illustrative embodiments for particular applications, it should be understood that the disclosure is not limited thereto. Modifications can be made to the embodiments described herein without departing from the spirit and scope of the present disclosure. Those skilled in the art with access to this disclosure will recognize additional modifications, applications, and embodiments within the scope of this disclosure and additional fields in which the disclosed examples could be applied. Therefore, the following detailed description is not meant to be limiting. Further, it is understood that the systems and methods described below can be implemented in many different embodiments of hardware. Any actual hardware described is not meant to be limiting. The operation and behavior of the systems and methods presented are described with the understanding that modifications and variations of the embodiments are possible given the level of detail presented. 
         [0027]    References to “one embodiment,” “an embodiment,” “in certain embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
         [0028]    The delivery systems disclosed herein can include a moldable handle capable of translating linear relative movement between multiple shafts simultaneously to deliver a valve prosthesis. The delivery systems can include a two-part prosthesis containment capsule which can maintain a compressible interference fit, mitigating risks associated with snagging during retraction of the delivery system. The delivery system handle can be reversibly decoupled, allowing for rapid closure of the prosthesis containment capsule after delivery of the prosthesis. The decoupling mechanism can be user operated and can include a safety feature to prevent premature actuation. 
         [0029]    The delivery system can also include a safety stop feature, which can permit only partial deployment of the valve prosthesis support arms, such as by impeding the pathway of the support arm screw, to allow repositioning or recapturing of the prosthesis. The user can then choose to release the safety stop button to allow completion of the support arm deployment. 
         [0030]    The delivery system can also include a delivery catheter, which can have a two-part prosthesis containment capsule divided into distal and proximal portions. To deploy the prosthesis, the proximal capsule portion can be retracted proximally to release the prosthesis arms, which can engage with the ascending aorta. The distal capsule portion can be advanced distally to release the prosthesis inflow section, which can engage the native leaflets of the heart valve. After deployment, the distal and proximal capsule portions can be returned to their closed, pre-deployment configuration to allow safe removal of the delivery system through the deployed prosthesis. 
         [0031]    Without the prosthesis loaded within the capsule, the open capsule sections may not align concentrically after deployment, and can create “open mouth” sections which can damage or snag on the deployed prosthesis. In certain embodiments, the delivery system can include a centering element, which can facilitate guiding the two capsule sections back together and align them concentrically. In certain embodiments, the centering element can be a self-expanding centering frame. During loading and deployment, the center frame can be collapsed under the valve prosthesis. Upon deployment, the centering frame can expand, which can also help disengage the valve prosthesis from the valve retainer. Once the valve prosthesis is deployed, the distal capsule portion can be retracted over the centering frame&#39;s tapered distal profile to align it concentrically with the proximal capsule portion. The proximal capsule portion can then be advanced over the centering frame&#39;s tapered proximal profile to concentrically align it with the distal capsule portion. 
         [0032]    In certain embodiments, the centering element can be a centering shaft with a tapered distal profile, which can facilitate guiding the two capsule portions together and align them concentrically. During loading and deployment, the centering shaft can be retracted proximally from the valve prosthesis. Once the valve prosthesis is deployed, the centering shaft can be advanced to the proximal face of the valve retainer, which can help disengage the valve prosthesis from the valve retainer. At this point, the distal capsule portion can be retracted over the centering shaft&#39;s tapered distal profile to align it concentrically with the proximal capsule portion. The proximal capsule portion can then be advanced over the centering shaft to concentrically align it with the distal capsule portion. The delivery system can then be safely retracted through the deployed valve prosthesis. 
         [0033]      FIG. 1  illustrates delivery system  100 , according to an embodiment. Delivery system  100  can include handle  200  and catheter  300 . Handle  200  can include front grip  210 , rear grip  212 , valve release knob  202 , support arm knob  204 , safety stop button  206 , handle decoupling button  208 , and decoupling portion  209 . Catheter  300  can include outer shaft  302  and capsule  304 . Capsule  304  can include proximal capsule portion  306 , distal capsule portion  308 , intermediate shaft  310 , valve containment sleeve  312 , and capsule tip  314 . 
         [0034]    In certain embodiments, valve containment sleeve  312  can be a cylindrical polymer sleeve, configured to retain a heart valve prosthesis within capsule  304 . In certain embodiments, capsule tip  314  can be an atraumatic tip to prevent damage to the body lumen as delivery system  100  is advanced through the body. In certain embodiments, capsule tip  314  can include an opening at its distal end to allow delivery system  100  to pass over a guide wire. In certain embodiments, capsule tip  314  can be radiopaque to facilitate locating delivery system  100  within the body using medical imaging. 
         [0035]      FIGS. 2A-2C  illustrate close-up views of handle  200 , according to an embodiment. Handle  200  can include front grip  210  and rear grip  212 . Front grip  210  and rear grip  212  can be ergonomically designed to facilitate grasping of handle  200  by the user. Front grip  210  and rear grip  212  can be made of a moldable material, such as plastic or rubber, which can provide a smooth and frictional gripping surface. Front grip  210  and rear grip  212  can include grip flush ports  214 , which can be used, for example, to remove air or add fluid to delivery system  100 . Rear grip  212  can also include end flush port  216 , which can also be used for these purposes, and additionally for inserting surgical tools through handle  200 . As shown in  FIG. 2B , front grip  210  (and/or rear grip  212 ) can include grooves  218  to further facilitate gripping handle  200 . 
         [0036]    Handle  200  can also include support arm knob  204 , valve release knob  202 , safety stop button  206 , and handle decoupling button  208 . These features can be used to deploy the valve prosthesis and rejoin the capsule portions after deployment, and will be described in further detail below. 
         [0037]      FIGS. 3A-3D  illustrate the deployment and retraction sequence for the valve prosthesis contained within capsule  304 , according to an embodiment.  FIG. 3A  illustrates the initial retraction of outer shaft  302  and proximal capsule portion  306 , as indicated by the arrow. Proximal capsule portion  306  can be retracted in the proximal direction, for example, by rotating support arm knob  204 . It is understood that the term support arm knob is exemplary. By support arm knob, the disclosure includes knobs, slides, switches and other similar structures that can be activated to cause proximal capsule portion  306  to move axially. 
         [0038]    A safety stop feature can be located on handle  200 , for example, within support arm knob  204 , and can prevent proximal retraction of proximal capsule portion  306  beyond a predetermined distance. The safety stop feature can permit only partial deployment of the valve prosthesis support arms. Medical imaging can be used to determine the location of the support arms, and, if not in the proper location, the valve prosthesis can be repositioned or recaptured. Once in the proper deployment location, the user can activate safety stop button  206  on support arm knob  204  to allow further proximal retraction of proximal capsule portion  306 , as indicated by the arrow in  FIG. 3B . It is understood that reference to the safety stop button is exemplary, and not meant to be limiting. The safety stop button can be a button, switch, knob, or other similar structures that can prevent proximal retraction of proximal capsule portion  306 . 
         [0039]      FIG. 3B  illustrates capsule  304  with proximal capsule portion  306  in a fully retracted position. In this fully retracted position, proximal dome  316 , which can be located at a proximal end of intermediate shaft  310 , can be exposed. Proximal dome  316  can facilitate mating of proximal capsule portion  306  and distal capsule portion  308 . Proximal dome  316  can include flushing slots  318 , which can deliver a flushing fluid to the distal end of catheter  300 . In certain embodiments, intermediate shaft  310  shown in  FIG. 3B  can be stationary relative to outer shaft  302  and inner shaft  320 . 
         [0040]    At the stage of deployment illustrated in  FIG. 3B , valve containment sleeve  312  can still contain the inflow section of the valve prosthesis.  FIG. 3C  illustrates advancement of distal capsule portion  308  in the distal direction, as indicated by the arrow. Distal capsule portion  308  can be advanced distally, such as by rotating valve release knob  202 . It is understood that the term valve release knob is exemplary. By valve release knob, the disclosure includes knobs, slides, switches and other similar structures that can be activated to cause distal capsule portion  308  to move axially. 
         [0041]    Valve release knob  202  can control inner shaft  320 , which, in certain embodiments, can move within an interior lumen of intermediate shaft  310 , and can be connected to distal capsule portion  308 . By advancing distal capsule portion  308 , and thus valve containment sleeve  312 , in the distal direction, valve retainer  322  can be exposed, thus releasing the valve prosthesis. Valve containment sleeve  312  can form a frictional interference fit with valve retainer  322 , which can prevent distal capsule portion  308  from advancing too far in the distal direction. 
         [0042]      FIG. 3D  illustrates proximal retraction of distal capsule portion  308 . Manual retraction of distal capsule portion  308  can be performed, for example, by rotating valve release knob  202  in a direction opposite to the direction that advances distal capsule portion  308 . Manual retraction of distal capsule portion  308  can also be performed by pressing handle decoupling button  208 , which can decouple decoupling portion  209  of handle  200 . The user can then pull decoupling portion  209  of handle  200  proximally. This movement can pull inner shaft  320 , which can be connected to distal capsule portion  308 , in the proximal direction, thus retracting distal capsule portion  308  proximally to mate with proximal capsule portion  306 . Once capsule  304  is closed, delivery system  100  can be safely retracted through the deployed valve prosthesis and removed from the body. 
         [0043]      FIGS. 4A and 4B  illustrate an interior view of support arm knob  204  and the safety stop mechanism, according to an embodiment. By way of example, as the user rotates support arm knob  204 , screw engager  302 A of outer shaft  302  can engage support arm deployment screw  220 . Generally, safety stop button  206  can be in a spring-loaded safety position, as shown in  FIG. 4A . Once screw engager  302 A reaches stopper  206 A of safety stop button  206 , outer shaft  302  is prevented from being retracted further in the proximal direction. At this point, the support arms of the valve prosthesis are partially deployed, and can be repositioned or recaptured, if necessary. Once the valve prosthesis is in the proper location, the user can slide safety stop button  206  in the proximal direction, which can move stopper  206 A proximally within slot  222 . Outer shaft  302  can then be further retracted within handle lumen  224  in the proximal direction to fully deploy the support arms of the valve prosthesis. 
         [0044]      FIGS. 5A and 5B  illustrate the decoupling mechanism, according to an embodiment.  FIG. 5A  shows a partial interior view of handle decoupling portion  209 . The handle decoupling mechanism can include one or more handle decoupling buttons  208 , which can include coupling elements  211 . It is understood that the term handle decoupling buttons is exemplary. By handle decoupling buttons, the disclosure includes knobs, slides, switches and other similar structures that can be activated to allow decoupling of a proximal portion of handle  200 . In certain embodiments, coupling elements  211  can engage a counterpart of support arm knob  204  to keep support arm knob  204  and handle decoupling portion  209  together during deployment of the valve prosthesis. Once the valve prosthesis is deployed, the user can press handle decoupling buttons  208 , which can decouple coupling elements  211 , and allow handle decoupling portion  209  and the rest of the proximal portion of handle  200  to be retracted rapidly in the proximal direction. This movement occur manually, whereby the user pulls handle  200  in the proximal direction. This can retract inner shaft  320 , and therefore distal capsule portion  308 , in the proximal direction to mate with proximal capsule portion  306  and close capsule  304 . 
         [0045]      FIGS. 6A and 6B  illustrate a close-up view of valve retainer  322 , according to an embodiment. Valve retainer  322  can include landing zone  324 , retaining portion  326  and one or more valve notch  328 . In certain embodiments, portions of valve retainer  322  can be radiopaque, which can facilitate locating the delivery system using medical imaging. As illustrated in  FIG. 6B , valve retainer  322  can be connected to the distal end of intermediate shaft  310 . Valve notch  328  can be either cut into the surface of retaining portion  326  or raised on the surface of retaining portion  326 . Valve notch  328  can correspond to a feature on the valve prosthesis to retain the valve prosthesis within capsule  304  until deployment. Landing zone  324  can be a smooth cylindrical surface located at the distal end of valve retainer  322 . Landing zone  324  can prevent prosthesis flaring when engaged with the capsule, and can eliminate hang up points. As inner shaft  320  is advanced in the distal direction to deploy the inflow part of the valve prosthesis from within distal capsule portion  308 , valve containment sleeve  312  can ride up on landing zone  324 . An interference fit can be created between valve containment sleeve  312  and landing zone  324  of valve retainer  322 . This can prevent distal capsule portion  308  from advancing too far in the distal direction during deployment of the valve prosthesis. In certain embodiments, landing zone  324  can be made of a low durometer polymer or rubber and retaining portion  326  can be made of metal, such as stainless steel. 
         [0046]      FIG. 6C  illustrates a close-up view of valve retainer  322 , according to another embodiment. Valve retainer  322  can be made from metal which has a notch, indentation and/or a mark on the side of landing zone  324 , such as notch  332 . Notch  332  can facilitate positioning of the delivery catheter under fluoroscopy by providing a differentiating appearance to aid with accurate deployment of the prosthesis. In certain embodiments, landing zone  324  can be configured to accommodate notch  332  and allow it to be covered by polymer sleeve  330  to cover the gap created by notch  332  to maintain proper fit between valve retainer  322  and capsule  304 . Polymer sleeve  330  can be non-radiopaque, thus allowing valve retainer  322  to have features to facilitate accurate positioning while maintaining a round profile for a smooth fit with capsule  304  and for a smooth edge for retracting valve retainer  322  through the prosthesis after deployment. 
         [0047]      FIGS. 7A and 7B  illustrate a capsule centering element, according to an embodiment. In certain embodiments, the capsule centering element can be centering frame  400 . Centering frame  400  can be connected to intermediate shaft  310 , such as by attachment ring  402 , which can be located at either a proximal or distal end of centering frame  400 . Attachment ring  402  can be crimped about intermediate shaft  310  to secure centering frame  400  to intermediate shaft  310 . Centering frame  400  can be made of a self-expanding shape memory alloy, such as nitinol. In certain embodiments, centering frame  400  can be made from a laser-cut metal tube. In certain embodiments, centering frame  400  can be made of a plurality of wires  406 , such as nitinol wires, welded to attachment ring  402 . In certain embodiments, centering frame  400  can include radiopaque marker  404 , which can facilitate positioning the valve prosthesis and aligning distal capsule portion  308  and proximal capsule portion  306  using medical imaging. 
         [0048]    When the valve prosthesis is loaded in capsule  304 , self-expanding centering frame  400  can be collapsed under the valve prosthesis. When the valve prosthesis is deployed, centering frame  400  can expand to provide a lead in for distal capsule portion  308  to mate with proximal capsule portion  306 . The expansion of centering frame  400  can also facilitate disengaging the valve prosthesis from valve retainer  322 . In certain embodiments, centering frame  400  can be coated with a biocompatible lubricant to facilitate guiding distal capsule portion  308  and proximal capsule portion  306  back together. In certain embodiments, centering frame  400  can at least partially recollapse as distal capsule portion  308  and proximal capsule portion  306  slide over centering frame  400  and back together. 
         [0049]    As illustrated in  FIGS. 8A and 8B , in certain embodiments, the capsule centering element can be centering funnel  500 . Centering funnel  500  can be connected to intermediate shaft  310 , such as by attachment ring  502 , which can be located at either a proximal or distal end of centering funnel  500 . Centering funnel  500  can be made of a self-expanding shape memory alloy, such as nitinol. In certain embodiments, as illustrated, for example, in  FIG. 8B , centering funnel  500  can be a nitinol sheet rolled into a funnel or spring shape. In certain embodiments, centering funnel  500  can be constrained within an elastomeric sleeve, which can expand with centering funnel  500 .  FIG. 8B  provides a view along a longitudinal axis of delivery system  100 , showing centering funnel  500  coiled within proximal capsule portion  306  prior to delivery of the valve prosthesis. Generally, the expanded diameter of centering funnel  500  can be less than or equal to the diameter of distal capsule portion  308  and proximal capsule portion  306 . In certain embodiments, proximal capsule portion  306  can be guided distally over centering funnel  500  to mate with distal capsule portion  308 . In certain embodiments, distal capsule portion  308  can be pulled proximally over and around centering funnel  500  to mate with proximal capsule portion  306 . 
         [0050]    Once the valve prosthesis is deployed, centering funnel  500  can expand in diameter, thus creating a funnel shape to provide a guide for distal capsule portion  308  to mate with proximal capsule portion  306 . In certain embodiments, centering funnel  500  can be manually expanded, such as by balloon inflation. In certain embodiments, centering funnel  500  can be coated with a biocompatible lubricant to facilitate guiding distal capsule portion  308  and proximal capsule portion  306  back together. In certain embodiments, centering funnel  500  can at least partially recollapse as distal capsule portion  308  and proximal capsule portion  306  slide over centering funnel  500  and back together. 
         [0051]    In certain embodiments, the capsule centering element can be structures such as, but not limited to, a cell-like stent structure or a braided cylinder, attached to intermediate shaft  310  by attachment ring  402  at one or more end. 
         [0052]    As illustrated in  FIGS. 9A and 9B , as well as  FIGS. 10A and 10B , in certain embodiments, the capsule centering element can be centering shaft  600 . Centering shaft  600  can be, for example, a polymer or composite shaft that can slide independently along intermediate shaft  310 . Centering shaft  600  can be retracted proximately to allow the valve prosthesis to be loaded within capsule  304  prior to the valve replacement procedure. In certain embodiments, centering shaft  600  can have a continuous proximal profile and tapered tip  602 , which can facilitate mating of distal capsule portion  308  with proximal capsule portion  306 . After the valve prosthesis is deployed, centering shaft  600  can be advanced distally out of proximal capsule portion  306 . Centering shaft  600  can be advanced to the proximal face of valve retainer  322  to facilitate disengaging the valve prosthesis from valve retainer  322 . Distal capsule portion  308  can then be retracted proximally, such as by rotating valve release knob  202  to retract inner shaft  320  in the proximal direction. Distal capsule portion  308  can slide over tapered tip  602  of centering shaft  600 . Proximal capsule portion  306  can also be advanced distally to concentrically mate proximal capsule portion  306  with distal capsule portion  308 . In certain embodiments, centering shaft  600  can be coated with a biocompatible lubricant to facilitate guiding distal capsule portion  308  and proximal capsule portion  306  back together. In certain embodiments, proximal retraction of distal capsule portion  306  can be performed by activating handle decoupling button  208 . 
         [0053]    As illustrated in  FIGS. 10A and 10B , in certain embodiments, centering shaft  600  can include centering dome  604 . Centering dome  604  can include distal taper  606  and proximal taper  608 . In the embodiments shown in  FIGS. 10A and 10B , centering shaft  600  can operate in a mechanistically similar manner as in  FIGS. 9A and 9B . After distal capsule portion  308  is advanced distally to deploy the valve prosthesis, centering shaft  600  can be advanced distally up to valve retainer  322  to facilitate disengaging the valve prosthesis from valve retainer  322 . Distal capsule portion  308  can be retracted proximally such that distal capsule portion  308  and valve containment sleeve  312  slide over distal taper  606  of centering dome  604 . Proximal capsule portion  306  can be advanced in the distal direction over proximal taper  608  of centering dome  604  to mate with distal capsule portion  308 . In certain embodiments, proximal retraction of distal capsule portion  306  can be performed by activating handle decoupling button  208 . 
         [0054]    Methods of delivering a heart valve prosthesis are also disclosed. References to the figures are made by way of example, and are not meant to be limiting. Prior to the procedure, the desired valve implantation location should be determined. This can be done with the assistance of medical imaging, such as a CT scan. For trans-aortic prosthetic aortic valve implantation, the implantation location can generally be located within the aortic sinus such that the distal part of the heart valve prosthesis engages the leaflets of the native aortic valve, and the proximal part of the heart valve prosthesis engages the inner wall of the ascending aorta. Alternative implantation sites can be used, and the optimal implantation site can be determined for each individual patient. 
         [0055]    Generally, for a trans-aortic procedure, the chest can be prepared and the ascending aorta can be accessed, such as by a mini-sternotomy or a thoracotomy. In certain embodiments, the user can place delivery system  100  over a guide wire and advance delivery system  100  through the ascending aorta. In certain embodiments, medical imaging can be used to locate features of delivery system  100  to facilitate positioning of delivery system  100  at the desired deployment location. 
         [0056]    Once in the desired anatomical position, the user can, for example, rotate support arm knob  204  to retract outer shaft  302 , and therefore proximal capsule portion  306 , to partially release the valve support arms. If the support arms are not in the desired deployment location, the valve prosthesis can be repositioned or recaptured. Once the user verifies that the support arms are correctly positioned, proximal capsule portion  306  can be fully retracted. In certain embodiments, this can be accomplished by pressing safety stop button  206  and further rotating support arm knob  204 . The user can then advance distal capsule portion  308 , for example, by rotating valve release knob  202 . Once the valve prosthesis is fully deployed, the user can activate handle decoupling button  208  to initiate rapid closure of capsule  304 . The user can then retract delivery system  100  through the deployed valve prosthesis and remove it from the body. The user can then close the incision by standard clinical techniques. 
         [0057]    In certain embodiments, after distally advancing distal capsule portion  308  to deploy the valve prosthesis, the user can advance centering shaft  600  in the distal direction. Distal capsule portion  308  can then be retracted proximally over tapered tip  602  of centering shaft  600 . Proximal capsule portion  306  can be advanced distally to mate proximal capsule portion  306  with distal capsule portion  308 . In certain embodiments, a self-expanding capsule centering element can expand after deployment of the valve prosthesis. The capsule centering element can help guide distal capsule portion  308  and proximal capsule portion  306  back together. 
         [0058]    The foregoing description has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the precise embodiments disclosed. Other modifications and variations may be possible in light of the above teachings. The embodiments and examples were chosen and described in order to best explain the principles of the embodiments and their practical application, and to thereby enable others skilled in the art to best utilize the various embodiments with modifications as are suited to the particular use contemplated. By applying knowledge within the skill of the art, others can readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein.