Abstract:
An apparatus for endovascularly replacing a patient&#39;s heart valve. In some embodiments, the apparatus includes a replacement heart valve implant comprising a valve and an expandable anchor; and a deployment tool adapted to endovascularly deliver the replacement heart valve implant to an implant site within the patient, the deployment tool comprising an actuator adapted to exert an axially directed force on the anchor. The invention also provides a method for endovascularly replacing a heart valve of a patient. In some embodiments, the method includes the steps of endovascularly delivering a replacement heart valve implant having a valve and an anchor to an implant site within the patient; and applying an axially directed force from an actuator outside of the patient to the anchor. In invention also provides deployment tools for performing the method.

Description:
CROSS-REFERENCE  
       [0001]     This application is a continuation-in-part application of U.S. patent application Ser. No. 10/982,388, filed Nov. 5, 2004, which is a continuation-in-part application of U.S. patent application Ser. No. 10/746,120, filed Dec. 23, 2003, and is a continuation-in-part application of U.S. patent application Ser. No. 10/870,340, filed Jun. 16, 2004, which applications are incorporated herein by reference in their entirety and to which applications we claim priority under 35 USC § 120. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The invention relates generally to medical implant systems. In particular, the invention relates to a tool to endovascularly deliver and deploy a medical implant, such as a replacement heart valve. Aspects of the invention may also be used to deliver and deploy other medical implants and to deliver those implants percutaneously, endoscopically, laparoscopically, etc.  
         [0003]     Medical devices may be implanted within patients&#39; bodies for a variety of medical purposes. Many implants can be delivered in a minimally invasive manner, such as through percutaneous access to the patient&#39;s vasculature, through an existing orifice, etc. For example, replacement heart valves may be endovascularly delivered to a patient&#39;s heart, as described in more detail in U.S. patent application Ser. No. 10/982,388; U.S. patent application Ser. No. 10/746,120, filed Dec. 23, 2003; and U.S. patent application Ser. No. 10/870,340, filed Jun. 16, 2004. Multiple implant operations may need to be performed during the minimally invasive delivery and deployment of a medical implant; the prior art is replete with handles and actuators for these purposes.  
         [0004]     Replacement heart valves may be delivered endovascularly to the patient&#39;s heart from an entry point far from the patient&#39;s heart. For example, replacement aortic valves can be delivered retrograde (i.e., against the blood flow) from an insertion point near the patient&#39;s groin through the femoral artery and the aorta. Any physician-operated actuators used to deliver, deploy, retrieve or otherwise operate the replacement valve or its components must perform their operations over this distance. In addition to any expansion of the valve and/or anchor from a deployment shape or self-expanded shape to a deployed shape, these operations may include expansion of the replacement valve against the inward force of the tissue in and around the patient&#39;s native valve. Each of these operations could require the delivery of an expansion force from the external actuator to the implant. Other possible valve replacement procedure operations controlled by external actuators include detachment of the delivery tool from the implant after a successful placement procedure, collapsing and moving an implant to a more desirable implant location, and retrieval of the implant back into a delivery tool catheter or sheath.  
       SUMMARY OF THE INVENTION  
       [0005]     The invention provides a medical implant and implant deployment tool and methods of use. One aspect of the invention provides an apparatus for endovascularly replacing a patient&#39;s heart valve, with the apparatus including a replacement heart valve implant comprising a valve and an expandable anchor; and a deployment tool adapted to endovascularly deliver the replacement heart valve implant to an implant site within the patient, the deployment tool comprising an actuator adapted to exert an axially directed force on the anchor. In some embodiments, the deployment tool is adapted to provide a force of 5 to 35 pounds from the actuator to the anchor and/or a mechanical advantage of at least 2:1 from the actuator to the anchor. The mechanical advantage may be variable over a movement range of the actuator.  
         [0006]     In some embodiments, the implant also includes a lock, the deployment tool being adapted to operate the lock to maintain the implant in an expanded configuration. This operation may be performed by either controlling the locking or unlocking of the lock, or both. In some embodiments, the actuator includes an anchor actuator, the deployment tool further having a sheath and a sheath actuator adapted to move the sheath with respect to the anchor. In some embodiments, the actuator includes an anchor actuator, with the deployment tool further having an unlocking actuator adapted to unlock the anchor from a locked configuration. In some embodiments, the actuator includes an anchor actuator, with the deployment tool further including a valve actuator adapted to move the valve with respect to the anchor, and, optionally, a nosecone actuator adapted to move a nosecone with respect to the anchor.  
         [0007]     In some embodiments the deployment tool further includes an anchor actuation element operably connecting the actuator with the anchor, the actuator and anchor actuation element being adapted to provide movement of a distal end of the anchor actuation element at a variable speed as the actuator moves at a constant speed. In some embodiments, the deployment tool further includes a feedback mechanism providing information indicating a deployment state of the implant.  
         [0008]     In some embodiments the deployment tool further includes a plurality of actuators each adapted to perform a different deployment operation. The deployment tool may also include an actuator interlock adapted to prevent operation of one of the actuators before operation of another of the actuators. The actuators may also be arranged on the deployment tool in a preferred order of operation. For example, in some embodiments the actuator includes an anchor actuator, with the deployment tool further including a sheath, a sheath actuator adapted to move the sheath with respect to the anchor, an implant attachment element adapted to attach the implant to the deployment tool, and a release actuator adapted to detach the attachment element from the implant, with the anchor actuator being disposed between the sheath actuator and the release actuator on the deployment tool. In some embodiments one actuator may also be adapted to operate the plurality of actuation elements, perhaps sequentially. The actuator may also include a power source, such as a solenoid, motor, hydraulic or pneumatic cylinder, etc. A clutching mechanism may also be provided to limit a force transmitted from an actuator to an implant.  
         [0009]     Another aspect of the invention provides a method for endovascularly replacing a heart valve of a patient, with the method including the following steps: endovascularly delivering a replacement heart valve implant having a valve and an anchor to an implant site within the patient; and applying an axially directed force from an actuator outside of the patient to the anchor. Some embodiments include one or more of the following steps: using an actuator to move a sheath with respect to the anchor; using an actuator to release the anchor from the deployment tool; using an actuator to lock the anchor in an expanded configuration; using an actuator to unlock the anchor from a locked configuration; using an actuator to move the replacement valve with respect to the anchor; and/or applying an outward pressure from expansion of the anchor to the implant site of at least about 7 psi.  
         [0010]     In some embodiments of the method, the actuator provides a mechanical advantage of at least about 2:1, and the mechanical advantage may vary over an actuator movement range. In some embodiments, an anchor actuation element operably connects the actuator with the anchor, and the applying step includes moving a distal end of the anchor actuation element at a variable speed as the actuator moves at a constant speed. Some embodiments also provide the step of providing information about completion of actuation through a feedback mechanism.  
         [0011]     In some embodiments, the applying step includes the step of applying the expansion force with a first actuation element, with the method further including the step of performing a second replacement valve deployment operation using a second actuation element. In some embodiments, the actuator interfaces with the first and second actuation elements. Some embodiments also include the step of operating an actuator interlock before operating the second actuation element. In some embodiments, the actuator is a first actuator, with the performing step including the step of performing the second replacement valve deployment operation with a second actuator. Some embodiments further include the step of performing a third replacement valve deployment operation with a third actuator, wherein the actuators are arranged in an operation order, the method further comprising the step of operating the actuators in the operation order.  
       INCORPORATION BY REFERENCE  
       [0012]     All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:  
         [0014]      FIG. 1  is a partial cross-sectional view of an implant and deployment tool according to an embodiment of this invention.  
         [0015]      FIG. 2  is a cross-sectional view of an implant and part of a deployment tool according to another embodiment of this invention.  
         [0016]      FIGS. 3A and 3B  are schematic views of an implant and part of a deployment tool according to yet another embodiment of this invention.  
         [0017]      FIGS. 4A and 4B  are elevational views of part of an implant and part of a deployment tool according to still another embodiment of this invention, with the implant being cut open and laid flat for viewing purposes.  
         [0018]      FIG. 5  is an elevational view of a locking mechanism for an implant.  
         [0019]      FIG. 6  is an elevational view of another locking mechanism for an implant and part of a deployment tool.  
         [0020]      FIG. 7  is an elevational view of yet another locking mechanism for an implant and part of a deployment tool.  
         [0021]      FIG. 8A  is a perspective view of an implant and part of a deployment tool according to an embodiment of this invention.  
         [0022]      FIGS. 8B-8D  are cross-sectional views of a release mechanism for the implant and deployment tool of  FIG. 8A .  
         [0023]      FIG. 9  is a perspective view of a locking mechanism for an implant and part of a deployment tool according to yet another embodiment of the invention.  
         [0024]      FIGS. 10A-10C  are perspective views of part of an implant deployment tool according to an embodiment of the invention showing deployment tool actuators.  
         [0025]      FIGS. 11A-11E  are schematic views of part of an implant deployment tool according to another embodiment of the invention showing deployment actuators.  
         [0026]      FIG. 12  is a schematic view of part of an implant deployment tool according to yet another embodiment of the invention showing a deployment actuator operating multiple actuation elements.  
         [0027]      FIG. 13  is a schematic view of part of an implant deployment tool according to still another embodiment of the invention showing a deployment actuator operating multiple actuation elements at least partially sequentially.  
         [0028]      FIG. 14  is a schematic view of part of an implant deployment tool according to another embodiment of the invention showing a deployment actuator operating multiple actuation elements at least partially sequentially.  
         [0029]      FIG. 15  is a cross-sectional view of part of an implant deployment tool according to yet another embodiment of the invention showing a deployment actuator operating multiple actuation elements.  
         [0030]      FIG. 16  is a side elevational view of the implant deployment tool of  FIG. 15  with several elements removed.  
         [0031]      FIGS. 17A and 17B  are schematic views of an implant deployment tool according to yet another embodiment of the invention showing a deployment tool actuator operating multiple actuation elements.  
         [0032]      FIGS. 18A-18C  are schematic views of an implant deployment tool according to still another embodiment of the invention showing a deployment tool actuator operating multiple actuation elements.  
         [0033]      FIG. 19A  is a schematic view of an implant deployment tool actuator and actuation element according to yet another embodiment of the invention.  
         [0034]      FIG. 19B  is a partial exploded view of the implant deployment tool actuator and actuation element of  FIG. 19A .  
         [0035]      FIG. 20  shows part of an implant deployment tool with positive confirmation of actuation of an implant.  
         [0036]      FIG. 21  shows part of a power operated implant deployment tool. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]     The medical implant deployment tool of this invention may be used to deliver, deploy, implant, release, retrieve and otherwise actuate a medical implant.  FIG. 1  shows one embodiment of an implant  10  and deployment tool  100 . In this embodiment, the implant is a replacement heart valve incorporating a valve  20  and an anchor  30  (such as a braided stent) designed to be delivered to the patient&#39;s heart endovascularly from an opening in the patient&#39;s femoral artery. Deployment tool  100  supports implant  10  at least in part via actuation elements  106  disposed at the distal end of a delivery catheter  108  within an outer sheath  110 . A handle  120  is connected to delivery catheter  108  at its proximal end. A nosecone  104  (which may be collapsible) extends from the distal end of sheath  110  as the implant  10  and sheath  110  are advanced through the patient&#39;s vasculature to the patient&#39;s heart over a guidewire  102 .  
         [0038]     Deployment tool  100  also has actuators and other user controls at its proximal end for use by a physician during the implant procedure. For example, located in handle  120  are slidable actuators  122  and  124  disposed in tracks  123  and  125 , respectively, as well as a rotating actuator  126 . Actuators  122 ,  124  and  126  may be connected to actuation elements (not shown) used to perform implant deployment operations. One such operation (by moving, e.g., actuator  122  within handle  120 ) draws the distal end of anchor  30  proximally with respect to the anchor&#39;s proximal end, while actuation elements  106 , delivery catheter  108  and handle  120  provide a countervailing force on the anchor&#39;s proximal end. This axially directed anchor expansion force may be between about 5 pounds and about 35 pounds, with the expanding anchor providing outward pressure on the patient&#39;s tissue at the implant site of between about 7 psi and about 28 psi. In addition, a circumferential handle actuator  111  is provided on sheath  110  to move delivery catheter  108 , which is connected to handle  120 , with respect to sheath  110 . This relative movement may be used, e.g., to apply an axially directed force by the sheath on the proximal end of anchor  30  to resheath the anchor and valve. In some embodiments, this resheathing force may be between about 5 pounds and about 35 pounds.  
         [0039]      FIG. 2  illustrates certain implant deployment operations performed by a deployment tool. The implant in this embodiment is a replacement heart valve with a valve element  220  supported within a radially expandable anchor  230 . In this embodiment, anchor  230  may be expanded radially by applying an axially directed force to foreshorten the anchor. The axially directed force is applied on the distal end of anchor  230  by pulling valve support post  238  proximally using deployment tool actuation elements  250  (such as threads or control wires) that pass through eyelets  245  formed in the arrowhead shaped locking elements  244  of posts  238 . While the posts are pulled proximally, a countervailing axially directed force is applied to the proximal end of anchor  230  by axially stiff deployment tool actuation elements  260 . This axially directed anchor expansion force may be between 5 pounds and about 35 pounds, with the expanding anchor providing outward pressure on the patient&#39;s tissue at the implant site of between about 7 psi and about 28 psi. Foreshortening concludes when locking elements  244  pass into buckle-shaped locking elements  240 . The deployment tool may be detached from the implant by, e.g., releasing one end of actuation elements  250  and pulling the free end through eyelets  245 , and releasing one end of attachment elements  262  and pulling their free ends through the anchor attachment sites  242  (e.g., closed cells at the proximal end of a braided stent) to release actuation elements  260  from anchor  230 . Movement of the actuation elements and attachment elements may be controlled using deployment tool actuators (not shown) located on the exterior of the patient.  
         [0040]      FIGS. 3A and 3B  show another embodiment of a replacement heart valve implant and parts of its deployment tool.  FIG. 3A  shows the implant and deployment tool in a delivery configuration in which a valve  326 , its support posts  322  and a seal  328  extend distally of a radially expandable anchor  330 . During deployment, axially directed forces are applied on the implant via deployment tool actuation elements  350  and  352  to foreshorten and expand anchor  330 , to rotate posts  322  to their deployed position, and to place seal  328  on the outside of anchor  330 , as shown in  FIG. 3B . Locking elements (not shown) on the free ends of posts  322  interact with locking elements  340  on the proximal end of anchor  330  to lock anchor  330  in its expanded configuration. As in the other embodiments, movement of actuation elements  350  and  352  may be controlled using deployment tool actuators (not shown) located on the exterior of the patient.  
         [0041]      FIGS. 4A and 4B  show yet another embodiment of a medical implant and part of its deployment tool. The implant may be, e.g., the anchor portion of a replacement heart valve, similar to those described above. For visualization purposes, braided anchor  402  has been opened and flattened in  FIGS. 4A and 4B . Locking posts  404  (which may be used to support a replacement heart valve within anchor  402 ) are attached to the distal end of anchor  402 , and buckle-shaped locking elements  408  are attached to the proximal end. Actuation elements  414  passing through locking elements  408  and attached to holes  403  formed in the proximal ends of posts  404  may be used to apply an axially directed force on the distal end of anchor  402  (against a countervailing force applied to the proximal end of anchor  402  by other actuation elements, not shown) to foreshorten and radially expand the anchor from the delivery configuration shown in  FIG. 4A  to the locked and deployed configuration shown in  FIG. 4B . When locked, locking tabs  410  formed in locking elements  408  mate with corresponding holes  406  formed in posts  404 . In this embodiment, the anchor may be unlocked by pulling an unlocking actuation element  416  proximally. This movement removes tabs  410  from holes  406 , thereby releasing posts  404  and permitting anchor  402  to elongate and radially shrink, thereby enabling the implant to be moved within the patient or removed from the patient. If, however, the anchor is to remain locked and the implant is to remain in the patient, deployment tool actuation elements  414  and  416  may be detached from the implant by releasing one end and pulling the free end through. Movement of deployment tool actuation elements  414  and  416  may be controlled using deployment tool actuators (not shown) located on the exterior of the patient.  
         [0042]      FIG. 5  shows details of a locking mechanism for a medical implant, such as a replacement heart valve with a radially expandable anchor as described above. A locking element  506  formed at the proximal end of a post  502  (such as a valve support post) interacts with a locking element  504  formed in or attached to the proximal end of an anchor. A hole  508  is formed in the proximal end of post  502  for use with a deployment tool actuation element (not shown).  
         [0043]      FIG. 6  shows another embodiment of a locking mechanism for a medical implant, such as a replacement heart valve with a radially expandable anchor as described above. In this embodiment, the anchor has multiple locking positions corresponding to multiple deployed diameters. Thus, the implant&#39;s post  602  (which may also be used, e.g., as a valve support) has multiple locking elements  606  with bendable arms  610  and  612 . In the state shown in solid lines in  FIG. 6 , as the post  602  is pulled proximally toward and through anchor locking element  604  (via, e.g., a deployment tool actuation element passing through hole  608  in post  602 ) the anchor locks are restrained by a lock actuator  614  passing through holes  616  formed in arms  610  and  612 , allowing the post locking elements  606  to pass through the anchor locking element  604  without engaging. This feature permits the user to visualize the location of the implant and to maneuver the implant within the patient before finally deploying the implant. By pulling lock actuator  614  free of holes  616 , however, the resilient or shape memory action of arms  610  and  612  enables the arms to move to the position shown in phantom in  FIG. 6 , thereby enabling the post locking element to lock with the anchor locking element. As with the other embodiments, movement of deployment tool actuation element  614  may be controlled using deployment tool actuators (not shown) located on the exterior of the patient.  
         [0044]      FIG. 7  shows yet another embodiment of a multiple position locking mechanism for a medical implant (such as a replacement heart valve with radially expandable anchor). As in the embodiment shown in  FIG. 6 , post  702  (which may be a valve support post) has multiple locking elements, each with bendable arms  710  and  712 . In this embodiment, the post may be drawn proximally into an anchor locking element  704  by pulling proximally on deployment tool actuation element  716  passing through a hole  708  formed in the proximal end of the post. In the deployment configuration shown in the left side of  FIG. 7 , as the post is drawn proximally toward locking element  704 , the bendable locking element arms  710  and  712  are restrained by an actuation element  714  shaped like an overtube that passes through locking element  704 . When locking is to be permitted (e.g., after confirmation of implant location, procedure safety and efficacy, etc.), actuation element  714  may be drawn proximally to permit arms  710  and  712  to assume their locking positions, as shown on the right side of  FIG. 7 . As with the other embodiments, movement of deployment tool actuation elements  714  and  716  may be controlled using deployment tool actuators (not shown) located on the exterior of the patient.  
         [0045]      FIGS. 8A-8D  illustrate one embodiment of an implant release mechanism.  FIG. 8A  shows a replacement heart valve implant with a valve  804  supported within an anchor  802 . The implant is attached to a deployment tool via attachment elements  810  and actuation elements  808  extending from a distal end of a delivery catheter  806 . As shown in  FIGS. 8B-8D , to release anchor  802  from the deployment tool, attachment element  810  may be moved proximally with respect to the actuation element  808  to pull its free end  812  through the closed cell of anchor  802 . This movement may be controlled, e.g., by an actuator (not shown) on the exterior of the patient.  
         [0046]      FIG. 9  is a perspective view of a locking mechanism for an implant and part of a deployment tool according to yet another embodiment of the invention. In this embodiment, post  901  (such as a post used to lock a radially expandable medical implant anchor and optionally to support a valve within the anchor) is attached to an anchor (not shown) by looped threads  906 . In this embodiment, post  901  has valve support elements  903  and a locking element  905  whose position with respect to support elements  903  may be adjusted. In an alternate embodiment, elements  903  and  905  may be formed of a single piece of material. Arms  909 , on locking element  905 , help hold locking element  905  and support elements  903  in place. Holes  908  formed in support elements  903  may be used to attach a valve to the post. A tooth  910  formed on the proximal end of locking element  905  serves as a locking element interacting with a corresponding detent  911  on a lever arm  913  on an anchor locking element  904 , which may be attached to the anchor by sutures or threads passing through holes  912 . To foreshorten and radially expand the anchor to which post  901  and locking element  904  are attached, an axially directed force is applied to the anchor by applying a proximally directed force on post  901  via deployment tool actuation element  914  (which passes through post  901  and around a release pin  920 ) while providing a countervailing axially directed force on the proximal end of the anchor. Insertion of tooth  910  into locking element  904  locks the anchor in an expanded configuration. The anchor may be unlocked by pulling proximally and radially in on an unlocking actuator  916  (which passes around a release pin  924 ), which moves detent  911  of locking element  904  away from the tooth  910  of post  901 . If, however, the user wishes to maintain the locked configuration, actuation elements  914  and  916  may be detached by pulling on release actuation elements  918  and  922  to remove release pins  920  and  924 , respectively. As in the other embodiments, movement of actuation elements  914 ,  916 ,  918  and  922  may be controlled by actuators located exterior to the patient.  
         [0047]      FIGS. 10A-10C  show details of deployment tool actuators according to one embodiment of the invention. Deployment tool  1000  may be used, e.g., to endovascularly deliver and deploy a medical implant, such as a replacement heart valve. Deployment tool handle  1002  supports a plurality of actuators, such as a rotating actuator  1006  controlling movement of a sheath  1003  (located within a handle extension  1004 ) and a rotating actuator  1008  which may be used, e.g., to apply an axially directed force on posts of a replacement heart valve anchor through actuation elements (not shown) extending through sheath  1003 . The rotating actuators may provide mechanical advantage to the implant deployment operations. For example, sheath actuator  1006  may be used to move sheath  1003  distally with respect to the implant to resheath the implant. The axially directed force required to resheath the implant may be between, e.g., about 5 pounds and about  35  pounds. To facilitate this operation, actuator  1006  and its associated gear connection to the sheath (e.g., rack and pinion gears) are designed to provide a mechanical advantage of at least about 2:1.  
         [0048]     In some deployment operations, it may be important to ensure that certain deployment steps are performed before other deployment steps, some of the actuators may be configured and arranged such that they cannot be operated before other actuators have been operated or until other actuators are in a particular position. In this embodiment, for example, one of the actuators is formed as an access door  1010 . Actuator  1010  maybe used, e.g., to release an anchor lock prevention mechanism, thereby finalizing the implant deployment operation. Movement of actuator  1010  provides access to another actuator, rotating actuator  1014 , which may then be used to release the actuation elements (e.g., the actuation elements transmitting the axially directed forces to the anchor, the anchor lock prevention mechanism, etc.) from the implant.  
         [0049]      FIGS. 11A-11E  show another embodiment of a medical implant deployment tool for, e.g., delivery and deployment of a replacement heart valve, such as the valve embodiment shown in  FIGS. 3A and 3B . A rotating actuator  1106  may be used to retract a sheath  1104  with respect to a delivery catheter  1103  via corresponding threads on the actuator and sheath as shown; the threads provide a mechanical advantage (of, e.g., 2:1) but may not be needed for the entire movement distance of the sheath, as shown. Also in this embodiment, the actuators  1108 - 1118  are arranged in a preferred order of operation and operate corresponding actuation elements (such actuation element  1120  connected to actuator  1114 ). For example, actuator  1118  may be used to rotate the posts  322  of  FIG. 3  from the position shown in  FIG. 3A  to the position of  FIG. 3B , and actuator  1116  may be used to move the posts from the position shown in  FIG. 3B  to that of  FIG. 3A . Actuator  1114  may be used to pull the posts  322  (and therefore the distal end of anchor  330 ) proximally with respect to the proximal end of the anchor to expand the anchor. Actuator  1112  may be used to unlock the posts  322  from the buckle lock element  340 , and actuators  1108  and  1110  may be used to release the implant from the delivery tool.  
         [0050]     In addition, some of the actuators have features that prevent operation of one actuator until another actuator has been operated so that the implant deployment operations are performed in a desired order. For example, movement of actuator  1118  from the position shown in  FIG. 11B  to the position shown in  FIG. 11C  (to move the posts from the  FIG. 3A  position to the  FIG. 3B  position) brings one end of actuator  1118  into contact with a stop  1124  formed on actuator  1116 , thereby preventing actuator  1116  (which moves the posts back to the  FIG. 3A  position) from moving until actuator  1118  is returned to its other position, as shown in  FIG. 11E . In addition, a detent  1122  formed in actuator  1114  interacts with actuator  1116  as shown in  FIG. 11D  to prevent actuator  1116  from moving until actuator  1114  is moved again to provide slack in the actuation elements for movement of the posts, as shown in  FIG. 11E .  
         [0051]      FIG. 12  shows an embodiment of a medical implant deployment tool in which a single actuator  1206  operates multiple actuation elements  1224  and  1226 . The deployment tool may be used, e.g., to endovascularly deliver and deploy a medical implant, such as a replacement heart valve. Actuator  1206  extends from a proximal end of a deployment tool handle  1202 . Rotation of actuator  1206  turns a spool  1208  within handle  1202 . Actuation element arms  1216  and  1218  are supported within handle  1202  by linkages  1220  and  1222 , respectively, and ride within grooves  1212  and  1214 , respectively, formed in spool  1208 . As spool  1206  turns, arms  1216  and  1218  move proximally and distally, thereby moving actuation elements  1224  and  1226  to perform implant deployment steps. The mechanical advantage provided by the actuator depends on the slope of grooves  1212  and  1214  and may change over the movement limits of the actuator, as in the embodiment shown in  FIG. 12 . In addition, the varying slope of grooves  1212  and  1214  provides for varying speed of actuation to, e.g., move one end of an expanding anchor at a varying speed as the actuator moves at a constant speed. Also, use of a single actuator ensures that the implant deployment steps will be performed in a particular order or otherwise in a synchronized fashion.  
         [0052]      FIG. 13  shows another embodiment of a medical implant deployment tool (used, e.g., to deliver and deploy a replacement heart valve) in which one actuator  1302  controls multiple actuation elements  1312 ,  1316  and  1320 . As shown, threads  1306  of actuator  1302  mate with threads formed on a gear  1314  connected to actuation element  1316 , and threads  1308  of actuator  1302  mate with threads formed on a gear  1318  connected to actuation element  1320 . Rotation of actuator  1302  in the position shown in  FIG. 13  draws gears  1314  and  1318 , and actuation elements  1316   1320 , proximally. A lip  1322  extending from gear  1314  travels within a groove  1324  formed in gear  1318  to limit the amount that gears  1314  and  1318 , and therefore actuation elements  1316  and  1320 , can move with respect to each other. In particular, when threads  1306  are engaged with the threads on gear  1314 , but before threads  1308  have engaged the threads on gear  1318 , gear  1314  and actuation element  1316  move independently of gear  1318  and actuation element  1320 . When lip  1322  comes to the limit of its movement in groove  1324 , however, gears  1314  and  1318  will move together, bringing threads  1308  into contact with the threads on gear  1318 . A similar lip and groove arrangement is provided on gear  1318  and a third threaded gear  1310 , which is connected to actuation element  1312 , so that proximal movement of gear  1318  to the limit of the lip&#39;s movement within the groove causes gear  1318  to engage gear  1310  and the threads on gear  1310  to engage threads  1304  on actuator  1302 . Thus, rotation of actuator  1302  moves actuation elements  1312 ,  1316  and  1320  in a synchronized fashion and ensures that the implant deployment steps will be performed in a particular order.  
         [0053]      FIG. 14  shows yet another embodiment of a medical implant deployment tool (used, e.g., to deliver and deploy a replacement heart valve) in which one actuator  1402  controls multiple actuation elements  1416 ,  1418  and  1420 . In the position shown in  FIG. 14 , threads  1404  of actuator  1402  mate with threads on gear  1412  connected to actuation element  1418 . Rotation of actuator  1402  moves gear  1412  and actuation element  1418  linearly and can be used to apply an axially directed force (of, e.g., between about 5 pounds and about 35 pounds with a mechanical advantage of at least 2:1) on a medical implant (not shown) connected to actuation element  1418 . To move actuator  1402  to a position in which the actuator can engage and control other actuation elements, spring-biased button  1422  can be depressed, which moves detent element  1408  out of the groove  1406  of actuator  1402 , thereby enabling actuator  1402  to move forward or back. In the forward position (i.e., to the right as shown in  FIG. 14 ), threads  1404  of actuator  1402  engage threads formed in gear  1414  which is connected to actuation element  1420 . In the back position (i.e., to the left as shown in  FIG. 14 ), threads  1404  of actuator  1402  engage threads formed in gear  1410 , which is connected to actuation element  1416 .  
         [0054]      FIGS. 15 and 16  show yet another embodiment of the invention used, e.g., to deliver and deploy a replacement heart valve or other medical implant. An actuator  1502  connects to a toothed ratchet wheel  1506  via a shaft  1504 . A ratchet mechanism (not shown) extending from another portion of the deployment tool engages teeth  1508  of ratchet wheel  1506  to limit rotation of actuator  1502  to one direction. Also attached to shaft  1504  are three fixed clutch elements  1510 . A spool clutch element  1512  surrounds each fixed clutch element  1510 ; the interface between the each fixed clutch element  1510  and spool clutch element  1512  pair forms sliding clutch friction surfaces  1514 . A spool  1518  connects to each spool clutch element  1512  via a spring  1516 . A medical implant deployment tool actuation element (such as a thread or control wire) is wound about and extends from each spool  1518 . Actuator  1502  may be rotated in the direction permitted by the ratchet mechanism to, e.g., wind the actuation elements  1520  about the spools  1518 . If the resistance force presented by an actuation element  1520  exceeds the slip point of the associated clutch (i.e., when the force on the actuation element exceeds the friction force provided by the clutch&#39;s friction surface), the clutch will slip and the spool  1518  will stop rotating. This friction point may be designed to slip at a force below the break point of the actuation element. In addition, use of a spring  1516  between the spool  1518  and its associated spool clutch element  1512  helps maintain tension on each actuation element. This embodiment provides for simultaneous actuation of multiple actuation elements with a single actuator.  
         [0055]      FIGS. 17A and 17B  show still another embodiment of a medical implant deployment tool according to the invention. In this embodiment, the deployment tool&#39;s rotatable actuator  1702  has an actuator interface  1704  that can mate with a plurality of actuation element interfaces  1706 , each connected to a different actuation element  1708 . The actuator  1702  may be moved about the deployment tool handle  1700  to engage the different actuation element interfaces  1706  as desired. An indicator  1712  may be used to provide the user with information about the position of the actuator, e.g., the operation that will be performed when the actuator is in that position. The actuation element interfaces  1706  may be arranged in the handle  1700  in the order in which actuation steps are to be performed.  
         [0056]      FIGS. 18A-18C  show yet another embodiment of a medical implant deployment tool using a single actuator to operate a plurality of actuation elements. In this embodiment, actuator  1802  may be rotated to engage its actuator interface  1803  with one of a plurality of actuation element interfaces  1804 . Each actuation element interfaces is connected to a spool  1806  about which an actuation element (not shown) may be wound. Once again, the actuation element interfaces  1804  may be arranged in the deployment tool handle in the order in which actuation steps are to be performed.  
         [0057]      FIGS. 19A and 19B  show another embodiment of the invention with a rotating actuator  1904  supported by a handle  1902 . A ratchet element  1914  interacts with a toothed ratchet wheel  1916  to limit rotation of actuator  1902  to the clockwise direction, as shown in  FIG. 19A . A spring biased ratchet release button  1918  may be depressed to release the ratchet and permit counterclockwise rotation of actuator  1904 . A spool  1922  surrounds a center shaft  1920  which is connected to actuator  1904 . Interior teeth  1928  of spool  1922  interact with deformable projections  1924  of shaft  1920  to form a clutch element; projections  1924  deform and slip between teeth  1928  when the rotation force between spool  1922  and shaft  1920  exceeds a designed slip level. An actuation element  1906  (used, e.g., to perform a medical implant deployment operation) winds about spool  1922  and has an optional spring portion  1908 . Also extending from actuation element  1906  is an indicator  1910  which aligns with markings  1912  on the deployment tool handle to show the position of the actuation element.  
         [0058]      FIG. 20  shows an embodiment that provides feedback to the user of the completion of an implant deployment operation. In this example, the implant is a replacement heart valve (such as those described above) having an anchor  2004 , posts  2006  and proximal locking elements  2008 . An actuator  2010  (such as one of the actuators described above) within handle  2002  moves an actuation element  2012  which is connected (in a manner not shown in  FIG. 20 ) to posts  2006 . When actuator  2010  moves posts  2006  into locking elements  2008 , an electrical connection is made through circuit controller  2041  and electrical conductors  2016  extending from the handle  2002  through the posts  2006  and locking elements  2008 . Closing the electrical circuit powers an indicator light  2018  providing feedback to the user to show that posts  2006  have been inserted into locking elements  2008  and that the anchor is now locked.  
         [0059]      FIG. 21  shows an embodiment of the invention in which the deployment tool employs a power source within handle  2102 , such as solenoid  2104 , to move the actuation element  2108 . Power source  2104  is actuated by depressing an actuator  2106 . Actuation element  2108  may be moved to perform, e.g., a medical implant deployment operation.  
         [0060]     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.