Abstract:
Apparatus for delivering a prosthetic heart valve into a patient by means that are less invasive than conventional open-chest, open-heart surgery. The prosthetic valve may be collapsed while in a delivery device. When the valve reaches the desired implant site in the patient, the valve can be released from the delivery device, which allows the valve to re-expand to the configuration in which it can function as a heart valve. For example, the delivery device may be constructed to facilitate delivery of the prosthetic valve into the patient via the apex of the patient&#39;s heart.

Description:
[0001]    This application is a continuation of U.S. patent application Ser. No. 12/452,128, filed Dec. 16, 2009, U.S. Pat. No. 8,512,398, which is a national phase entry under 35 U.S.C. §371 of International Application No. PCT/US2008/008022, filed Jun. 26, 2008, published in English, which claims the benefit of the filing date of U.S. provisional patent application 60/937,361, filed Jun. 26, 2007, the disclosures of which are hereby incorporated by reference herein in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to collapsible/expandable prosthetic heart valve delivery systems which can house, retain, maintain, transport, deploy, help anchor, and release (and, if necessary, reposition and/or retrieve) a collapsible prosthetic heart valve via a minimally invasive (or at least reduced invasiveness) port access, e.g., at the apex of a patient&#39;s heart and through the intercostal space of the patient&#39;s ribs. 
         [0003]    The field of collapsible/expandable prosthetic heart valves is relatively new. The general idea is to provide a prosthetic heart valve that can be collapsed to a relatively small size (diameter) for delivery into the patient with reduced invasiveness to the patient&#39;s body (typically via a tube of relatively small diameter). When the valve reaches the desired implant site in the patient, the valve is released from the delivery apparatus and expanded to its full operating size. This also includes securing the valve to tissue of the patient at the implant site. 
         [0004]    There are several approaches to delivering and deploying such collapsible/expandable prosthetic heart valves using arterial or venous systems of the patient. However, these approaches may impose certain constraints, such as requiring smaller delivery system profiles (cross sections) so that they can be used in diseased and smaller vessels and to minimize emboli risk. This may result in undesirable trade-offs in valve design and performance in order to accommodate the demand for delivery of the valve through smaller delivery system profiles. 
         [0005]    Ideally, the delivery system should be designed around a durable and efficient valve design, thus not compromising any of the valve&#39;s long-term implant performance requirements. In doing so, the valve design should be adequate for its intended performance and long-term durability functions. This may result in valve profiles in the collapsed state that are somewhat larger than would be appropriate for human artery or vein delivery approaches, thereby calling for an alternative route to delivering the valve to its intended implant site. 
         [0006]    The transseptal (through the septum of the heart) antegrade (delivery in the same direction as native blood flow) approach is one approach that has been tried. In the transseptal approach, access is gained through the venous circulatory system leading to the right atrium. A puncture is made through the septum wall separating the left and right atria (hence the term transseptal). The catheter is then advanced through the mitral valve into the left ventricle and looped back up ending at the aortic valve. This approach may have some disadvantages, however. For example, it may result in damage to the mitral valve and the associated chordae when trying to gain access to the aortic valve. In contrast, the transapical (through the apex of the heart) antegrade approach may offer a better and safer alternative for entering the left ventricle (“LV”) for direct access to the aortic and mitral valves. (See, for example, P. Tozzi et al., “Endoscopic off-pump aortic valve replacement: does the pericardial cuff improve the sutureless closure of left ventricular access?”, European Journal of Cardio-thoracic Surgery 31 (2007) 22-25, available online 6 Sep. 2006.) Accessing the LV through a small port at the apex (lower end) of the heart is not new, as this has been the practice for several decades in placing bypass shunts in pediatrics. There are good, long-term, clinical experiences with this access approach to render it safe and effective. With an optimum delivery system design, safer and more effective direct access to the aortic or mitral valve can be achieved for the purposes of repair and/or replacement of defective native valves. 
       SUMMARY OF THE INVENTION 
       [0007]    The delivery system of the present invention may comprise several components working together to facilitate various functions required for delivery and deployment of a collapsible/expandable prosthetic heart valve. The delivery system may include an elongated shaft attached to an ergonomic handle. The handle may incorporate several controls for several functional features within the device. One of these controls may be a rotating wheel that functions to advance/retract the valve prior to deployment and final release. Another control may be an outer shaft, which may contain a polymer sheath that functions as the valve-collapsing/expanding mechanism. Inside the outer shaft and within the sheath, there may be an internal movable shaft that is connected to the delivery device tip at the distal end of the delivery system. The shaft may be notched such that a wheel with teeth can engage and move the shaft axially when rotated in either direction (advance or retract). The prosthetic heart valve may be mounted onto this shaft and between the tip and a base. The base platform may function as a valve holding and constraining mechanism. The valve may rest on this base and can be secured in place using various mechanisms. For example, the base can have features and through-holes to allow the valve&#39;s proximal struts to be securely fastened using a suture that runs to the outside of the device at the handle on the proximal end. When the operator is satisfied with the position and orientation of the valve, the valve can be released by cutting and pulling out this suture. Alternatively, other mechanisms can be employed to secure the valve in place until final release. 
         [0008]    The internal movable shaft may contain multi-lumens that connect manifold ports at the proximal end of the device to one or more openings at or near the distal end (tip). These lumens can be utilized for various functions such as delivery of fluids (saline, contrast, etc.) and deployment of embolic protection devices, balloons for valvuloplasty, etc. 
         [0009]    Outside the outer shaft, a spring-loaded, donut-shaped component can be included to aid in sealing the apex of the heart or other access at the entry point by way of gentle pressure driven by the spring. 
         [0010]    The delivery system can be manufactured from materials that are known to be biologically compatible for short-term human interaction, since this device is not a permanent implant. However, material selection should take into account the fact that this device will come into contact with a permanent implant. 
         [0011]    The device handle can be injection molded from a bio-compatible polymer material. The elongated shaft can be polymeric or laser cut/machined surgical grade stainless steel. Internal working components can be either from a polymeric origin, stainless steel, shape-memory nitinol (nickel/titanium alloy) material, etc., depending on each component&#39;s function and performance requirements. The manifold can be an injection molded polycarbonate. The sealing donut can be made from various durometers of silicone. The device components may fit together using various means of interference fit, tabs, slots, glue, polymer heat bonds, and/or locking mechanisms to facilitate a seamless working system. 
         [0012]    Various advantageous features of the invention are identified (to some extent recapitulating the foregoing) in the next several paragraphs. 
         [0013]    Certain aspects of the invention relate to providing an ergonomic, hand-held, easy-to-use delivery system for collapsible/expandable prosthetic heart valves. Such a delivery system may include a handle and an elongated shaft that houses the valve. The handle can incorporate controls for specific functional features within the device. 
         [0014]    The delivery system may include valve release, retrieve, and/or reposition mechanisms. 
         [0015]    The device may include one or more radio-opaque marker bands (e.g., at or near the distal tip) for guidance and visualization of the delivery system (especially the distal end) under fluoroscopy in the case of all-polymer construction. 
         [0016]    The device may include precision, wheel-driven, advance/retract capabilities for precise valve positioning. Alternate mechanisms (e.g., a sliding lever) are also possible. 
         [0017]    The device may include capabilities for fully deploying the valve but not releasing it when recapture is desired. 
         [0018]    The device may include multi-lumen capabilities in the shaft for procedural support using ancillary devices such as guide wires, balloon catheters, embolic protection devices, fluids delivery (flushing or visualization), etc. 
         [0019]    The valve can be secured to internal features of the delivery system using different configurations. One way is to secure the proximal end of the valve to a holder base (e.g., using sutures, mechanical interference fit features, etc.). Another way is to utilize a suture (or polymer-covered thin wire or any other appropriate means similar to this) to run from the proximal end of the device (handle) through specifically designed structures within the valve. This strand can then run through specifically designed channels in the device tip and back inside the central lumen (or other specific lumen) and end outside the device by the handle where the operator can control it. Tensioning or loosening this wire/suture will cause the valve to deploy or re-collapse. This can be used to partially deploy the valve and recapture it for repositioning or retrieval as desired. 
         [0020]    A movable sheath, with an independent control at the handle, can function as the valve collapsing/expanding mechanism by advancing/retracting the sheath over the valve. The sheath may also maintain and protect the valve in the collapsed state. The sheath can also facilitate partial deployment and expansion of the valve, e.g., so that the operator of the apparatus can check for appropriate positioning of the valve in the patient. 
         [0021]    The device may include features in the tip and valve holder base to control valve orientation within the delivery system so that the valve can be deployed with the correct angular orientation about its longitudinal axis, e.g., to align commissures of the prosthetic valve relative to commissures of the native valve as desired. These features can be undercuts or depressions that correspond to features on the prosthetic valve, for example. 
         [0022]    Along with the conventional purse-string suture, a spring-loaded, silicone, molded, donut-shaped component can aid in sealing the entry port at the apex of the heart or other access into the patient&#39;s circulatory system. 
         [0023]    The device may include the capability of opening and closing off access to any of the lumen ports at the back manifold connector. 
         [0024]    The device tip may include features that allow the valve distal end to rest in a manner that controls the valve&#39;s collapsed diameter (e.g., to prevent damage to the stent and valve leaflets during collapse of the valve for minimally invasive delivery). 
         [0025]    The delivery system can include a fork-like structure that can protrude and extend outside the shaft near the distal end to force open calcified native heart valve leaflets (e.g., into the sinuses of the valsalva) in preparation for valve deployment and release. Another example of an embodiment for such purposes is to deploy a structure like an umbrella. Such an umbrella design can serve two functions: (1) calcified leaflet retention, pushing such native leaflet structures out of the way in preparation for new valve deployment, and (2) embolic protection, which can be achieved by incorporating a fine mesh within the deployed ribs of the umbrella, thus capturing any emboli from the procedure. Once the procedure is completed, this umbrella can be collapsed and retracted back into the shaft, thereby safely removing from the patient all emboli and any calcified debris. An example of a structure that can be used to collapse the umbrella when desired includes a thin strand (e.g., wire or suture) attached to each of the umbrella ribs. These strands extend into the main central lumen. Pulling these strands from the proximal end causes the ribs of the umbrella to collapse. 
         [0026]    The delivery system wheel can be centered in the handle for rotation access from both sides of the handle, or it can be offset to protrude from only one side of the device handle. 
         [0027]    The device preferably contains seals in various areas to prevent blood from seeping through the various channels and outside the heart. 
         [0028]    Further features of the invention, its nature and various advantages, will be more apparent from the accompanying drawings and the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a simplified elevational view of an illustrative embodiment of apparatus in accordance with the invention. 
           [0030]      FIG. 2  is a simplified isometric or perspective view of the  FIG. 1  embodiment. 
           [0031]      FIG. 3  is another simplified elevational view (with portions removed to reveal some of the interior) of the  FIG. 1  embodiment. 
           [0032]      FIG. 4  is a simplified isometric or perspective view of another illustrative embodiment of apparatus in accordance with the invention. 
           [0033]      FIG. 5  is a simplified partial elevational or perspective view (with portions removed to reveal some of the interior) of the  FIG. 4  embodiment. 
           [0034]      FIG. 6  is a simplified elevational or perspective view of portions of the above-mentioned embodiments. 
           [0035]      FIG. 7  is a simplified elevational or perspective view of portions of the  FIG. 4  embodiment. 
           [0036]      FIG. 8  is a simplified elevational view (with some portions removed) of an illustrative embodiment of apparatus that can be like the  FIG. 4  embodiment, with possible additional structure in accordance with the invention. 
           [0037]      FIG. 9  is another view that is generally like  FIG. 8 , but for a later stage in use of the apparatus in accordance with the invention. 
           [0038]      FIG. 10  is a simplified isometric or perspective view of portions of the  FIG. 4  apparatus. 
           [0039]      FIG. 11  is a simplified isometric or perspective view of portions of  FIG. 8 . 
           [0040]      FIG. 12  is a simplified isometric or perspective view of portions of  FIG. 4 . 
           [0041]      FIG. 13  is a view similar to  FIG. 12  for a later stage of operation of the apparatus in accordance with the invention. 
           [0042]      FIG. 14  is another view similar to  FIG. 13  for a still later stage in operation of the apparatus in accordance with the invention. 
           [0043]      FIG. 15  is still another view similar to  FIG. 14  for an even later stage in operation of the apparatus in accordance with the invention. 
           [0044]      FIG. 16  is yet another view similar to  FIG. 15  for a still later stage in operation of the apparatus in accordance with the invention. 
           [0045]      FIG. 17  is a simplified elevational view of an even later stage in operation of the  FIG. 16  apparatus in accordance with the invention. 
           [0046]      FIG. 18  is a simplified isometric or perspective view of what is shown in  FIG. 17 . 
           [0047]      FIG. 19  is another view similar to  FIG. 18  for a still later stage in operation of the apparatus in accordance with the invention. 
           [0048]      FIG. 20  is a simplified elevational view of what is shown in  FIG. 19 . 
           [0049]      FIG. 21  is a simplified elevational view of an illustrative embodiment of one component from several earlier FIGS. 
           [0050]      FIG. 22  is a simplified isometric or perspective view of what is shown in  FIG. 21 . 
           [0051]      FIG. 23  is a view, similar in some respects to  FIG. 4 , showing illustrative embodiments of possible additional components in accordance with the invention. 
           [0052]      FIG. 24  is a simplified isometric or perspective view of portions of what is shown in  FIG. 23 . 
           [0053]      FIG. 25  is a simplified elevational view of what is shown in  FIG. 24 . 
           [0054]      FIG. 26  is a simplified isometric or perspective view of portions of what is shown in  FIGS. 23-25 . 
           [0055]      FIG. 27  is a simplified, partial, elevational view, partly in section, showing an illustrative embodiment of possible features in accordance with the invention. 
           [0056]      FIG. 28  is a simplified sectional view showing an illustrative embodiment of other possible features in accordance with the invention. 
           [0057]      FIG. 29  is a simplified, partial, elevational view, partly in section, showing an illustrative embodiment of still other possible features in accordance with the invention. 
           [0058]      FIG. 30  is a simplified perspective or isometric view of an illustrative embodiment of a structure that can be used in apparatus in accordance with the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0059]    An illustrative embodiment of prosthetic heart valve delivery apparatus  10  in accordance with the invention is shown in  FIG. 1 .  FIG. 1  and several subsequent FIGS. omit all depiction of the prosthetic valve, but several still later FIGS. do show examples of such valves. The components of apparatus  10  that are visible in  FIG. 1  include handle  20 , control wheel  30 , outer shaft  40 , inner shaft  50 , distal tip  60 , and proximal (back) manifold connector  70 . Elements  40  and  70  are both fixed to handle  20 . Control wheel  30  is rotatable about an axis (perpendicular to the plane on which  FIG. 1  is drawn) to cause shaft  50  (and distal tip  60 ) to advance or retract relative to shaft  40 , depending on the direction of rotation of the control wheel. Distal tip  60  is fixed on the distal end of shaft  50 . Connector  70  may include one or more lumens that communicate with one or more lumens through other components of the apparatus. 
         [0060]    Elements  20 ,  30 , and  70  remain outside the patient at all times. Elements  40 ,  50 , and  60  are designed for insertion into a patient&#39;s body in a low invasiveness manner to deliver a prosthetic heart valve into the patient and to deploy (implant) that prosthetic heart valve in the patient. More particularly, the prosthetic heart valve is initially contained (in a collapsed condition) in a distal portion of apparatus  10  (i.e., inside shaft  40 , concentrically around shaft  50 , and abutting distal tip  60 ). In this condition of the apparatus, shaft  40  may help to keep the valve collapsed, and distal tip  60  (which is proximally retracted) may help to keep the valve inside shaft  40 . When the distal portion of the apparatus reaches the desired implant site for the valve in the patient, wheel  30  can be rotated to extend distal tip  60 , a distal portion of shaft  50 , and the prosthetic heart valve from the distal end of shaft  40 . This allows the prosthetic heart valve to expand radially outwardly from shaft  50  to its full operating size, which also causes the valve to engage surrounding native tissue of the patient and thereby implant in the patient. The apparatus can then be withdrawn (proximally) from the patient. In particular, distal tip  60  comes out through the center of the now-expanded valve. 
         [0061]    More details regarding the foregoing will be provided later in this specification. 
         [0062]    It should be noted that in the  FIG. 1  embodiment, shaft  40  is off-center relative to handle  20  (i.e., shaft  40  is somewhat below the top-to-bottom center of handle  20 ). On the other hand, wheel  30  is centered on handle  20  and is exposed for operation from either above or below the handle. 
         [0063]      FIGS. 2 and 3  show other views of apparatus  10 .  FIG. 3  shows apparatus  10  with half of handle  20  removed. This exposes the connection between wheel  30  and shaft  50 . In particular, it shows that there is a spur gear  32  on wheel  30  concentric with the axis of rotation of wheel  30 . This spur gear engages with a rack  52  on shaft  50 . These features allow rotation of wheel  30  to cause translation of shaft  50  along its longitudinal axis. (Features of this kind may be seen even more clearly for another embodiment in  FIG. 5 .) 
         [0064]    An alternative embodiment of device  10  is shown in  FIG. 4 . Even though the  FIG. 4  embodiment is somewhat different than the  FIGS. 1-3  embodiment, the same reference numbers continue to be used for generally similar elements. Thus additional information for such elements can be gleaned from earlier description of those elements, and it will not be necessary to repeat everything previously said for elements that are used again (at least in generally similar form) in different embodiments. 
         [0065]    The  FIG. 4  embodiment is different from the  FIGS. 1-3  embodiment in that in  FIG. 4  shaft  40  is centered (from top to bottom) on handle  20 . Another difference is that in  FIG. 4 , control wheel  30  is only operable from the top of handle  20 . 
         [0066]      FIG. 4  shows the possible addition of a toroidal or donut-shaped sealing ring  80  disposed concentrically around an intermediate portion of the length of shaft  40 . Ring  80  fits relatively closely around the outside of shaft  40 , but ring  80  is also axially slidable along shaft  40 . If ring  80  is moved in the proximal direction from the approximate starting position shown in  FIG. 4 , coil spring  90  (also disposed concentrically around shaft  40 ) acts to resiliently urge it back toward the starting position. Ring  80  can be located along shaft  40  so that when the distal portion of shaft  40  is pushed through an opening (aperture) in the apex of the patient&#39;s heart or other access to the patient&#39;s circulatory system, ring  80  bears against the outer surface of the tissue around the aperture and helps to reduce blood leakage from the circulatory system via the aperture. Spring  90  keeps ring  80  resiliently pressed against the outside of the tissue for this purpose. Ring  80  may be made of a softer material than other components of apparatus  10 . For example, ring  80  may be made of silicone. 
         [0067]      FIG. 5  shows an enlargement of a portion of the  FIG. 4  embodiment with part of handle  20  removed. Thus  FIG. 5  shows the spur gear  32  on wheel  30  engaging the rack  52  on shaft  50  as described earlier in connection with  FIG. 3 .  FIG. 5  also shows a tube  100  that may extend from connector  70  to a distal portion of the apparatus. For example, tube  100  may extend to opening  62  in the distal end of tip  60  for allowing fluid introduced via connector  70  to be released into the patient from the distal end of tip  60  for such purposes as providing fluoroscopically visible contrast in the patient. There may be more than one such tube  100 , which may go to different destinations in the device, and which may be for different purposes. Note that shaft  50  may be translatable axially (i.e., lengthwise) relative to tube  100 . 
         [0068]      FIG. 6  shows portions of elements  40  and  50  and element  60  on a larger scale.  FIG. 7  does the same for a portion of element  20  and element  70 .  FIG. 7  also shows that element  70  may include a valve  72  for selectively closing a lumen through that element. In particular, valve  72  may be controlled by the operator of the apparatus to close a lumen through connector  70 , e.g., to prevent blood from escaping from the patient via that lumen. When desired, the operator may open valve  72 , e.g., to allow fluid or some other auxiliary material or apparatus to be introduced into the patient via the associated lumen. Depicted valve  72  may be repeated for other lumens if desired. 
         [0069]      FIG. 8  shows an illustrative embodiment of a possible addition to what has been shown before. In particular,  FIG. 8  shows that a plurality of fingers  110  may be selectively deployed from the distal end of shaft  40  (when distal tip  60  is moved somewhat away from that distal shaft end) to push back native leaflets of a patient&#39;s native heart valve (which is going to be replaced by the prosthetic heart valve delivered by device  10 ). Fingers  110  may be initially confined in an annular array inside a distal portion of shaft  40 . When it is desired to deploy them (typically when the distal portion of the apparatus is appropriately positioned relative to the native valve that is to be replaced), fingers  110  can be pushed (part way) from the distal end of shaft  40 , and they then resiliently extend (radially) out farther from central shaft  50 , albeit still in an annular array as shown in  FIG. 8 . In this condition, fingers  110  push back the leaflets of the native valve (e.g., into the patient&#39;s native valsalva sinus) in order to help make appropriate room for deployment of the prosthetic valve within the native valve. As shown in  FIG. 30 , fingers  110  may be attached to a shaft  112  that runs longitudinally inside shaft  40  into handle  20 . Fingers  110  and their shaft  112  can be advanced or retracted relative to shaft  40  via a sliding control, lever, or the like that is on the outside of handle  20 . For example,  FIG. 30  shows a control member  114  attached to the proximal end of shaft  112 . Control member  114  can project from a slot in a side of handle  20 , where it can be manipulated by the user of the apparatus to advance or retract fingers  110 . Alternatively, control member  114  may connect to another actuator element on handle  20  for the same purpose as described in the preceding sentence. 
         [0070]      FIG. 9  shows a structure similar to what is shown in  FIG. 8 , with the addition of prosthetic valve  200  now deployed from near the distal end of the apparatus. Subsequent FIGS. show valve  200  and its deployment on a larger scale and in more detail, so more detailed discussion of the valve will be provided later in connection with those other FIGS. Here it is preliminarily noted that the principal components of valve  200  include an annular framework  210  (e.g., of metal) and a plurality of flexible valve leaflets  220  disposed within and mounted on that framework. Framework  210  and leaflets  220  are radially collapsible to a circumferential size that can fit inside shaft  40 . However, when shifted beyond the distal end of shaft  40  as shown in  FIG. 9 , framework  210  can resiliently expand (as shown in  FIG. 9 ), carrying leaflets  220  with the frame and positioning those leaflets relative to one another so that they can operate as a one-way, blood flow, check valve (like the native heart valve being replaced). 
         [0071]      FIG. 10  shows elements  80  and  90  (and portions of neighboring elements) on a still larger scale.  FIG. 11  does the same for elements  110  and portions of neighboring elements. Note the opening  62  in the distal end of tip  60 , which opening may communicate with a lumen through above-described tube  100 . 
         [0072]      FIGS. 12-20  show an illustrative embodiment of how valve  200  may be deployed. These FIGS. focus on valve  200  and the distal portion of delivery apparatus  10 .  FIG. 12  shows this portion of the apparatus in the condition that it has as it is being introduced into the patient (e.g., via an aperture in the apex of the patient&#39;s heart). Note that tip  60  is against the distal end of shaft  40  to give this portion of the apparatus a smooth exterior surface. 
         [0073]    When the distal portion of apparatus  10  reaches the desired location in the patient (i.e., the desired location for implanting the prosthetic heart valve), distal tip  60  and some associated structure may be displaced distally from the distal end of shaft  40  as shown in  FIG. 13 . This may be done by rotating wheel  30 . In addition to what has been shown in earlier FIGS.,  FIG. 13  shows that the apparatus may include a sleeve  120  around the outside of collapsed valve  200 , but inside collapsed fingers  110 . This sleeve may help to protect valve  200  from fingers  110 , and it may also facilitate the staged deployment of valve  200 . As  FIG. 13  shows, sleeve  120  initially moves in the distal direction with tip  60  and other elements that are inside sleeve  120 . 
         [0074]    The next step is shown in  FIG. 14 . In this step, fingers  110  are pushed part way out of the distal end of shaft  40  so that these distal portions of fingers  110  can spread radially outwardly and thereby push back the leaflets of the patient&#39;s native heart valve. A point should be made here as follows.  FIG. 14  and subsequent FIGS. may show the apparatus that is inside deployed fingers  110  at locations that are more distal to fingers  110  than would actually be the case. For example, elements  120  and  60  may not be distally as far from fingers  110  after deployment of those fingers as is shown in  FIG. 14  (and subsequent FIGS.). Instead, valve  200  may be deployed closer to deployed fingers  110  than the FIGS. alone may suggest. The FIGS. deviate from what may be the actual practice in this respect so that various parts can be seen more clearly (i.e., without overlapping and thereby obscuring one another). 
         [0075]    The next step is illustrated by  FIG. 15 . In this step, sleeve  120  is pulled back proximally to begin to expose prosthetic heart valve  200 . Although not shown in full detail in  FIG. 15  to avoid over-complicating the drawing, the distal portion of heart valve  200  typically begins to deploy (i.e., expand radially outwardly as indicated by arrows  202 ) as it is released from confinement within sleeve  120 . Thus the actual condition of valve  200  in  FIG. 15  is typically more like what is shown in  FIG. 29  (i.e., distal portion of valve (beyond sleeve  120 ) expanded radially out; proximal portion of valve (still within sleeve  120 ) still prevented by sleeve  120  from expanding radially out). 
         [0076]      FIG. 16  shows sleeve  120  pulled proximally back even farther so that valve  200  is now completely exposed. Once again, to avoid over-complicating the drawing,  FIG. 16  omits the fact that at this stage heart valve  200  is typically expanded radially outwardly along its entire length as indicated by the arrows  202  and  204  in  FIG. 16  and as is actually shown in  FIG. 17 .  FIG. 16  does, however, serve to illustrate the point that prior to the deployment of valve  200  (i.e., prior to its radial outward expansion), the axial position of the collapsed valve is maintained in the apparatus by positioning the valve between distal tip  60  and a more proximal collar  140  on shaft  50 . 
         [0077]      FIGS. 17 and 18  show additional structure that may be included in accordance with the invention. This is a system of flexible strands  130  that may be used (in conjunction with distal re-advancement of sleeve  120 ) to re-collapse valve  200  (either partly or wholly) in the event that it is found desirable or necessary to reposition the valve in the patient or to completely remove the valve from the patient after the valve has been partly or wholly expanded radially outwardly in the patient.  FIGS. 17 and 18  show the routing of strands  130  in this embodiment. A typical strand  130  comes from a proximal portion of the apparatus between shaft  50  and sleeve  120 . The strand  130  passes through an aperture in collar  140 , and then runs along the outside of valve  200  to an aperture in distal tip  60 . The strand passes through the interior of tip  60 , and then through the central lumen of shaft  50 , extending proximally all the way to the handle, where the strand ends can be controlled by the operator of the apparatus. There can be any number of similarly routed strands  130  spaced in the circumferential direction around the apparatus and valve  200 . Strands  130  are shown in a relatively loose or relaxed condition in  FIGS. 17 and 18 . However, they can be tightened by pulling on their proximal portions. 
         [0078]    An example of how strands  130  may be used is as follows. The gradual proximal retraction of sleeve  120  (described in earlier paragraphs) allows heart valve  200  to gradually deploy radially outwardly. Strands  130  are relaxed or loose at this time. The gradual deployment of valve  200  may be observed by the operator of the apparatus (e.g., via x-ray, fluoroscopy, or the like). If the valve is not going in as desired, expansion of the valve can be stopped by stopping the proximal retraction of sleeve  120 . Strands  130  can then be tightened by pulling proximally on their proximal portions, and at the same time sleeve  120  can be pushed in the distal direction. This combination of tightening strands  130  and pushing distally on sleeve  120  causes valve  200  to collapse back into the sleeve. The apparatus can then be repositioned to reposition valve  200  in the patient (after which the valve can be deployed again), or alternatively the valve can be completely removed from the patient with all of the surrounding instrumentation. Assuming that the valve remains in the patient, then when the operator of the apparatus is satisfied with its deployed position and condition, strands  130  can be removed (or effectively removed) by pulling on one proximal portion of each strand until the other end of that strand has been past valve  200  two times (once going in the distal direction, and then going in the proximal direction).  FIGS. 19 and 20  show the condition of the apparatus after strands  130  have thus been removed (or effectively removed). 
         [0079]    Strands  130  can be made of any suitably tensilely strong but laterally (transversely) flexible material. Examples include suture material, metal wire, or the like. 
         [0080]    Because  FIGS. 19 and 20  show valve  200  in the fully deployed condition and after strands  130  have been removed, these FIGS. offer the clearest views of valve  200  and therefore afford the best reference for the following further description of the valve. Although this description is provided in connection with  FIGS. 19 and 20 , it will be understood that the valve can be the same in all of the earlier-discussed FIGS. herein. On the other hand, it will also be understood that this particular construction of the prosthetic heart valve is only an example, and that many modifications, variations, and alternatives are also possible for the valve. 
         [0081]    As was mentioned earlier in this specification, principal components of valve  200  include frame  210  (e.g., of a highly elastic metal such as nitinol) and a plurality of leaflets (e.g., three leaflets)  220  of a flexible material such as tissue that has been rendered effectively inert and otherwise made suitable for long-term, non-reactive use in a patient&#39;s body. Leaflets  220  are secured to frame  210  in such a way that the leaflets can open (to allow blood to flow through the valve from left to right as viewed in  FIGS. 19 and 20 ) and close (to prevent blood from flowing through the valve from right to left as viewed in these FIGS.). 
         [0082]    The illustrative configuration of valve  200  that is shown in the FIGS. herein is particularly adapted for use as a prosthetic aortic valve. Details of valve  200  will therefore be described in that context. It will be understood, however, that this is only an example, and that the prosthetic valve can be alternatively configured differently in some respects to adapt it for use as a replacement for other valves in the heart or circulatory system. 
         [0083]    Frame  210  is preferably a continuous, one-piece, annular (ring-like) structure (e.g., a structure that has been cut (using a laser) from a tube and then further processed to achieve a desired shape). Frame  210  has a “lower” (upstream or blood inflow) portion  212  that extends in a serpentine (undulating or zig-zag) fashion all the way around the valve. This portion of frame  210  may be designed for implanting in or near the patient&#39;s native valve annulus. Frame  210  also includes an “upper” (downstream or blood outflow) portion  216  that also extends in a serpentine (undulating or zig-zag) fashion all the way around the valve. This portion of frame  210  may be designed for implanting in the patient&#39;s aorta downstream from the valsalva sinus of the patient. Frame portions  212  and  216  are connected to one another by a plurality of links or struts  214  that extend between those other frame portions at locations that are spaced from one another around the valve. Struts  214  may bow or bulge radially outwardly (as shown) to follow the inner surface of lobes of the valsalva sinus. 
         [0084]    Frame  210  may include commissure post members  218  that extend up from lower portion  212  at appropriate locations around the valve (analogous to the commissures of the patient&#39;s native heart valve). These posts  218  can form important portions of the frame structure to which leaflets  220  are attached. 
         [0085]    Frame  210  may also include other structures  219  that extend up and incline radially out from lower portion  212  to help hold back the patient&#39;s native valve leaflets, which (to the extent left remaining in the patient) are no longer functional. 
         [0086]    Frame  210  may also include barbs (e.g.,  211 ) at various locations to engage (and possibly penetrate) the patient&#39;s native tissue to help hold the valve in place where deployed in the patient. 
         [0087]    The point of making annular frame portions  212  and  216  serpentine is to facilitate annular (circumferential, radial) collapse and subsequent re-expansion of the valve. Such collapse is preferably elastic, and the subsequent re-expansion is preferably resilient. 
         [0088]    Although not shown herein, it will be understood that valve  200  may also include other components such as one or more layers of fabric and/or tissue on various parts of the valve. Such additional layers may be for such purposes as to promote tissue in-growth, to reduce the amount of contact between frame  210  and surrounding native tissue, to prevent moving portions of leaflets  220  from contacting frame  210 , etc. 
         [0089]    Illustrative details for collar  140  are shown in  FIGS. 21 and 22 . These features may include a distally extending, radially outer rim  142 , within which a proximal portion of valve  200  can be received when the valve is in the collapsed condition. This structure  142  can help to keep valve  200  confined to its collapsed condition prior to deployment. 
         [0090]    Other features of collar  140  may include recesses or sockets  144 , into which extreme proximal portions (e.g.,  211 ) of frame  210  may extend when valve  200  is in the collapsed condition. Such engagement between frame  210  and collar  140  can help ensure that valve  200  always maintains a known rotational (angular) orientation about the longitudinal axis of the apparatus. This can be helpful to ensure that rotation of apparatus  10  about its longitudinal axis produces exactly the same rotation of valve  200  about that axis. This may be important, for example, to help the operator of the apparatus position valve  200  for deployment with commissure posts  218  in a desired rotational or angular position relative to the patient&#39;s native valve commissures. As a specific example, it may be desirable for each commissure post  218  to be aligned with and inside a respective one of the patient&#39;s native valve commissures. This may necessitate rotation of apparatus  10  about its longitudinal axis, and features like  144  (with certain valve frame features received within those features  144 ) can help ensure that valve  200  has a known angular relationship to apparatus  10 , and that this angular relationship is always maintained until the valve is deployed from the apparatus. Snug engagement between collar  140  and shaft  50  is also part of this aspect of the invention in this embodiment. 
         [0091]    Still other possible features of collar  140  are apertures  146  for passage of above-described strands  130  through the collar. 
         [0092]      FIGS. 23-26  illustrate another possible feature of the apparatus. This is an embolic protection structure  300 , which may also include features for pushing back the leaflets of the native heart valve that is to be replaced by the prosthetic valve. Structure  300  will now be described. 
         [0093]    A purpose of apparatus  300  is to capture any debris (e.g., emboli) that may be dislodged from inside the patient during deployment of prosthetic heart valve  200  and/or the expansion of fork fingers  110 . Thus embolic protection apparatus  300  is typically deployed in the patient, early in the procedure, downstream from the location at which valve  200  will be deployed. For example, assuming that valve  200  is a replacement for the patient&#39;s native aortic valve, apparatus  300  may be deployed in the patient&#39;s aorta downstream from where the prosthetic valve will be employed. Apparatus  300  acts like a blood filter. It allows blood to flow through, but it captures any particles or the like that should not be allowed to remain in the patient&#39;s blood stream. After prosthetic valve  200  has been implanted, apparatus  300  is collapsed (still retaining any debris it has captured) and removed from the patient in the opposite way from which it was introduced. 
         [0094]    In this embodiment, apparatus  300  is a structure somewhat like an umbrella. In particular, structure  300  has a central shaft  310 , and a plurality of ribs or spokes  320  that are attached to a distal portion of shaft  310  and that can either collapse inwardly against (parallel to) shaft  310  or that can incline radially outwardly from shaft  310 . Another element of structure  300  is a flexible, emboli-catching web or mesh (blood filter)  330  attached to ribs  320 . Still other components of structure  300  are tethers  340  (shown only in  FIG. 26  to avoid over-complicating the other FIGS.). Tethers  340  run inside the proximal portion of shaft  310  and come out of apertures in the side wall of shaft  310  at locations that are adjacent to ribs  320 . Each tether  340  is attached to a respective one of ribs  320 . 
         [0095]    Before deploying valve  200 , apparatus  300  may be introduced into the patient in a collapsed condition via proximal connector  70 , a lumen through tube  100 , and distal tip aperture  62 . When apparatus  300  is at the desired location in the patient&#39;s circulatory system downstream from where valve  200  is to be implanted, the proximally directed tension on proximal portions of strands  340  may be released. This allows ribs  320  to resiliently deflect outwardly into an array somewhat like the ribs or spokes of an open umbrella. Ribs  320  carry out with them, and thus also open, blood filter web  330 . These structures (i.e.,  320  and  330 ) preferably bear against an annular portion of the inner surface of a blood vessel (e.g., the aorta) downstream from where valve  200  will be implanted in the patient. 
         [0096]    After valve  200  has been deployed, embolic protection apparatus  300  may be collapsed again by pulling proximally on tethers  340 . This causes ribs  320  to again become parallel to and against central shaft  310 . Blood filter  330  (with any captured debris) is thereby also collapsed against central shaft  310 . This allows apparatus  300  to be pulled back into device  10  via the aperture  62  in distal tip  60 . 
         [0097]    Note that apparatus  300  may include ribs  320  that extend proximally back from blood filter  330  per se. These rib extensions may serve the additional function of pushing back (radially outwardly) the leaflets of the patient&#39;s native heart valve prior to deployment of prosthetic valve  200 . 
         [0098]    After apparatus  300  (with above-mentioned, optional, proximal, rib extensions) has been deployed, the distal portion of device  10  may be moved distally closer to apparatus  300 . The distal portion of device  10  may then be opened and valve  200  may be deployed as shown in  FIGS. 23-25 . Because in this embodiment, deployed valve  200  may somewhat axially overlap with the proximal extensions of ribs  320 , after deployment of valve  200 , apparatus  300  may first be pushed in the distal direction to eliminate this overlap so that apparatus  300  can be re-closed without disturbing implanted valve  200 . This is also a convenient point to mention that after valve  200  has been deployed (in any embodiment, with or without apparatus  300 ), shaft  40  may be pushed distally through the implanted valve to again close against distal tip  60 . This restores the smooth outer surface to device  10 , which facilitates proximal withdrawal of device  10  through the implanted valve without disturbing the valve. If apparatus  300  is employed, it is preferably collapsed and returned to the interior of device  10  (or completely removed via device  10 ) prior to full withdrawal of device  10  through the implanted valve. 
         [0099]      FIG. 27  shows that a lumen through elements  70 ,  100 ,  60 ,  62  can be used for passage of a guide wire  400  through the apparatus. Thus a guide wire  400  can first be placed in the patient, and device  10  can thereafter be introduced into the patient by following along this guide wire. This guide wire lumen and/or other similar lumens through device  10  can alternatively or additionally be used for other purposes such as flushing, introduction and/or removal of other ancillary devices (e.g., embolic protection apparatus  300 ), etc. 
         [0100]      FIG. 28  shows other possible aspects of valve deployment and retrieval.  FIG. 28  shows the upstream end of valve  200  inside sheath  120  and bearing on collar  140 . Suture or wire strands  500  pass through collar  140  and are looped through upstream portions  212  of valve frame  210 . Strands  500  can be pulled in the proximal direction to hold the proximal (upstream) end of valve  200  against collar  140 . This also prevents the proximal end of valve  200  from expanding radially outwardly (even when sheath  120  is retracted proximally). However, when sheath  120  is retracted proximally past the proximal end of valve  200  and the tension on strands  500  is relaxed, the proximal end of valve  200  can expand resiliently outwardly. ( FIG. 29  shows this structure again (although it omits depiction of strands  500  to avoid over-complicating the drawing) with the distal (downstream) portion of valve  200  released from sheath  120  and resiliently expanded outwardly, but with the proximal portion of the valve not yet released.) 
         [0101]      FIGS. 28 and 29  show that the distal end of sheath  120  may flare radially outwardly as shown at  122 . This feature and strands  500  can be used to re-collapse valve  200  prior to its final release from device  10  if for any reason it is desired to reposition the valve in the patient or remove the valve from the patient. A combination of pulling proximally on strands  500  and pushing sheath  120  distally can be used to collapse valve  200  back down into sheath  120  with the proximal end of the valve seated against collar  140 . The valve can then either be positioned differently in the patient and again deployed, or the valve can be completely removed from the patient with device  10 . Assuming that valve  200  is going to be implanted in the patient, when the operator of the apparatus is satisfied with the placement of the valve in the patient, the valve is finally released from device  10  by allowing the downstream end of the valve to deploy and anchor against the aortic wall, and then deploying the upstream valve end. Finally, strands  500  are removed by releasing one end of each strand loop and using the other end of that loop to pull the released end sufficiently far so that the strand no longer prevents release of the valve from device  10 . 
         [0102]    It will be understood that the foregoing is only illustrative of the principles of the invention and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example, the shapes and sizes of various components can be different from the shapes and sizes employed in the illustrative embodiments shown herein. As another example, the lateral stiffness of shaft  40  and/or other longitudinal elements within shaft  40  can be selected to render the apparatus suitable for different possible uses and/or preferences. Thus in some embodiments it may be desirable for the shaft portion of the apparatus to be relatively stiff or even rigid or substantially rigid (i.e., not flexible or bendable transverse to or laterally of its longitudinal axis). On the other hand, in other embodiments it may be desirable for the shaft portion of the apparatus (or certain parts of the shaft portion) to be more laterally flexible.