Abstract:
The present disclosure relates to numerous devices and methods for transcatheter stented prosthetic heart valve loading and delivery. Such devices and methods reduce suture tangling and also provide the ability to adjust the stented prosthetic heart valve expansion and contraction prior to the final release of the stented prosthetic heart valve from the delivery device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Non-Provisional Patent Application claims the benefit of the filing dates of U.S. Provisional Patent Application Ser. No. 62/267,200, filed Dec. 14, 2015, entitled “Devices and Methods for Transcatheter Valve Loading and Implantation,” which is herein incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The disclosure relates to delivery devices and methods for transcatheter stented prosthetic heart valve loading and implantation. 
         [0003]    A human heart includes four heart valves that determine the pathway of blood flow through the heart: the mitral valve, the tricuspid valve, the aortic valve, and the pulmonary valve. The mitral and tricuspid valves are atrio-ventricular valves, which are between the atria and the ventricles, while the aortic and pulmonary valves are semilunar valves, which are in the arteries leaving the heart. Ideally, native leaflets of a heart valve move apart from each other when the valve is in an open position, and meet or “coapt” when the valve is in a closed position. Problems that may develop with valves include stenosis in which a valve does not open properly, and/or insufficiency or regurgitation in which a valve does not close properly. Stenosis and insufficiency may occur concomitantly in the same valve. The effects of valvular dysfunction vary, with regurgitation or backflow typically having relatively severe physiological consequences to the patient. 
         [0004]    Diseased or otherwise deficient heart valves can be repaired or replaced using a variety of different types of heart valve surgeries. One conventional technique involves an open-heart surgical approach that is conducted under general anesthesia, during which the heart is stopped and blood flow is controlled by a heart-lung bypass machine. 
         [0005]    More recently, minimally invasive approaches have been developed to facilitate catheter-based implantation of the valve prosthesis on the beating heart, intending to obviate the need for the use of classical sternotomy and cardiopulmonary bypass. In general terms, an expandable prosthetic valve is compressed about or within a catheter, inserted inside a body lumen of the patient, such as the femoral artery, and delivered to a desired location in the heart. 
         [0006]    The heart valve prosthesis employed with catheter-based, or transcatheter, procedures generally includes an expandable multi-level frame or stent that supports a valve structure having a plurality of leaflets. The frame can be contracted during percutaneous transluminal delivery, and expanded upon deployment at or within the native valve. With these delivery devices, the valved stent is crimped down to a desired size and held in that compressed state within a sheath for transluminal delivery. Retracting the sheath from this valved stent allows the stent to self-expand to a larger diameter, fixating at the native valve site. In more general terms, then, once the prosthetic valve is positioned at the treatment site, for instance within an incompetent native valve, the stent frame structure may be expanded to hold the prosthetic valve firmly in place. One example of a prosthetic valve is disclosed in U.S. Pat. No. 5,957,949 to Leonhardt et al., which is incorporated by reference herein in its entirety. 
         [0007]    The actual shape and configuration of any particular transcatheter prosthetic heart valve is dependent, at least to some extent, upon the valve being replaced or repaired (e.g., mitral valve, tricuspid valve, aortic valve, or pulmonary valve). The stent frame must oftentimes provide and maintain (e.g., elevated hoop strength and resistance to radially compressive forces) a relatively complex shape in order to achieve desired fixation with the corresponding native anatomy. Taken in combination, these design features can give rise to delivery obstacles. For example, when compressed and constrained within the delivery device&#39;s outer sheath capsule, a self-expanding stent frame will exert significant radial forces on the capsule. Thus, the capsule must have a robust construction, capable of statically resisting the applied force. However, the capsule, as well as other portions of the outer sheath, must also be sufficiently flexible to traverse the tortuous path leading to the native valve annulus site. As a point of reference, the preferred delivery approach oftentimes includes one or more significant bends or turns. In many instances, the native anatomy creates the “tight” or small radius of curvature bends; as the capsule (or other components of the delivery device) comes into atraumatic contact with the native anatomy, the native anatomy naturally assists in “forcing” the outer sheath (including the capsule) to the necessary shape. A retrograde approach to the aortic valve is but one example, where contact with the native anatomy assists in directing the delivery device about the significant curvature of the aortic arch. 
         [0008]    The present disclosure addresses problems and limitations with the related art. 
       SUMMARY 
       [0009]    The present disclosure relates to numerous delivery devices and methods for transcatheter stented prosthetic heart valve (“prosthetic valve”) loading and implantation. Such delivery devices can include an optional outer delivery sheath assembly, an inner shaft assembly and a handle assembly. The delivery device provides a loaded delivery state in which the prosthetic valve is loaded and compressed over the inner shaft assembly. The compression on the prosthetic valve is adjustable with one or more sutures. The delivery device is configured to permit the prosthetic valve to self-expand and partially release from the inner shaft assembly. 
         [0010]    Certain aspects of the disclosure are directed to delivery devices and methods for positioning a prosthetic valve in a compressed state for delivery and, subsequently, an expanded state for deployment at a native aortic heart valve. Such delivery devices are arranged and configured such that a plurality of sutures generally encircle the prosthetic valve. Each suture has two ends; wherein one end is fixedly secured to a wire and the second end is releasably secured to a release pin. Both the wire and the release pin are positioned within a spindle of the delivery device. When the wire is pulled away from the prosthetic valve in a proximal direction, the sutures are tensioned to place the prosthetic valve in a compressed state for delivery though a patient&#39;s vasculature. To deploy the prosthetic valve, the tension is released by moving the wire in a distal direction. As desired, the sutures can be re-tensioned to compress the prosthetic valve for repositioning. At the site of implantation, the release pin is pulled in a proximal direction to disengage the second ends of the sutures from the release pin. The delivery device, including the wire, release pin and sutures, is then withdrawn from the patient. 
         [0011]    Some aspects of the disclosure are directed toward alternate methods and delivery devices for loading a prosthetic valve to a catheter delivery device with sutures. In one such embodiment, a suture engagement member is positioned within the catheter and the suture engagement member engages at least one suture. The suture engagement member is then retracted proximally within the catheter, thus pulling the sutures proximally, to compress the prosthetic valve. To release compression and disengaged from the suture(s), the engagement member is pushed distally. The suture engagement member can take a variety of configurations suitable for engaging and disengaging the sutures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a perspective view of a delivery device for delivering a stented prosthetic heart valve. 
           [0013]      FIG. 2A  is a partial, schematic illustration of the delivery device of  FIG. 1  having a stented prosthetic heart valve positioned over an inner shaft assembly; the stented prosthetic heart valve shown in an expanded state. 
           [0014]      FIG. 2B  is a schematic illustration of the delivery device of  FIG. 2A  having the stented prosthetic heart valve positioned over the inner shaft assembly; a plurality of sutures compressing the stented prosthetic heart valve into a compressed state. 
           [0015]      FIG. 3  is a front view of a stented prosthetic heart valve that can be used with the delivery devices disclosed herein. 
           [0016]      FIG. 4  is a perspective view of an alternate stented prosthetic heart valve frame configuration. 
           [0017]      FIG. 5A  is a partial, schematic view of a delivery device for the delivery of a stented prosthetic heart valve before a suture assembly is secured to a spindle of the delivery device (only the stent frame of the stented prosthetic heart valve is shown for ease of illustration). 
           [0018]      FIG. 5B  is a partial, schematic view of the suture assembly of  FIG. 5A  partially positioned within a lumen of the spindle. 
           [0019]      FIG. 5C  is a partial, schematic view of the delivery device of  FIGS. 5A-5B  illustrating how three sutures are secured to a wire and also a release pin, both of which have been inserted into the lumen of the spindle. 
           [0020]      FIG. 6  is an exemplary suture actuation member placing tension in a suture positioned around the stented prosthetic heart valve of  FIG. 4  (only the stent frame is shown for clarity). 
           [0021]      FIG. 7A  is a perspective view of a suture actuation member, similar to that of  FIG. 6 , positioned within a catheter for loading of at least one suture (not shown). 
           [0022]      FIG. 7B  is a partial, perspective view of the suture actuation member of  FIG. 7A  positioned within the catheter to tension the at least one suture. 
           [0023]      FIG. 7C  is a partial, cross-sectional view of the suture actuation member of  FIGS. 7A-7B  positioned to release the at least one suture. 
           [0024]      FIG. 7D  is a partial, cross-sectional view of the suture actuation member of  FIGS. 7A-7C  having the sutures engaged to compress the stent frame. 
           [0025]      FIG. 7E  is a partial, side view of the suture actuation member of  FIGS. 7A-7D . 
           [0026]      FIGS. 8A-8B  are partial, side views of an alternate suture actuation member having a hook. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Specific embodiments of the present disclosure are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms “distal” and “proximal” are used in the following description with respect to a position or direction relative to the treating clinician. “Distal” or “distally” are a position distant from or in a direction away from the clinician. “Proximal” and “proximally” are a position near or in a direction toward the clinician. As used herein with reference to a stented prosthetic heart valve, the terms “distal” and “outflow” are understood to mean downstream to the direction of blood flow, and the terms “proximal” or “inflow” are understood to mean upstream to the direction of blood flow. Although the present disclosure has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present disclosure. 
         [0028]    As described below, aspects of the present disclosure relate to delivery devices utilizing one or more sutures to retain the stented prosthetic heart valve (“prosthetic valve”) in a compressed state during delivery to a target site. The suture related features of the present disclosure are useful with a variety of different delivery devices configurations. By way of background, general components of one non-limiting example of a delivery device  1  with which the present disclosures are useful are illustrated in  FIGS. 1-2B . The delivery device  1  is arranged and configured for percutaneously delivering a prosthetic valve  2  to a patient&#39;s defective heart valve. The delivery device  1  includes an optional outer delivery sheath assembly  3 , an inner shaft assembly  4 , and a handle assembly  5 . One or more sutures  7   a - 7   c  (schematically depicted) are provided, and can be considered part of the delivery device  1  in some embodiments or as part of the prosthetic valve  2  in other embodiments. The delivery device  1  provides a loaded delivery state in which the prosthetic valve  2  is loaded over the inner shaft assembly  4  and is compressively retained on a spindle  6  or the like by the sutures  7   a - 7   c . As is schematically illustrated in  FIGS. 2A-2B , the compression on the prosthetic valve  2  can be adjusted with one or more sutures  7   a - c.    
         [0029]    Once the loaded and compressed prosthetic valve  2  is located at a target site, tension in the sutures  7   a - 7   c  is lessened or released to permit the prosthetic valve  2  to self-expand, partially releasing and ultimately fully deploying the prosthetic valve  2  from the inner shaft assembly  4 . In the illustrated embodiment, the optional delivery sheath assembly  3 , where provided, includes a capsule  8 , selectively disposed over the prosthetic valve  2  that assists in constraining the prosthetic valve  2  in the loaded or compressed state and can be retracted by the handle assembly  5  to expose the prosthetic valve  2 . The present disclosure focuses on numerous devices and methods for prosthetic valve loading and implantation using a delivery device, such as the delivery device  1 . Such delivery devices utilize sutures for adjustably compressing and releasing said compression on the prosthetic valve either for loading or readjusting the position of a partially-deployed prosthetic valve. 
         [0030]    As referred to herein, prosthetic valves useful with the various devices and methods of the present disclosure may assume a wide variety of configurations, such as a bioprosthetic heart valve having tissue leaflets or a synthetic heart valve having polymeric, metallic or tissue-engineered leaflets, and can be specifically configured for replacing valves of the human heart. The prosthetic valves of the present disclosure may be self-expandable, for example. In general terms, the prosthetic valves of the present disclosure include a stent or stent frame having an internal lumen maintaining a valve structure (tissue or synthetic), with the stent frame having a normal, expanded condition or arrangement and collapsible to a compressed condition or arrangement for loading within the delivery device. For example, the stents or stent frames are support structures that comprise a number of struts or wire segments arranged relative to each other to provide a desired compressibility and strength to the prosthetic valve. The struts or wire segments are arranged such that they are capable of self-transitioning from, or being forced from, a compressed or collapsed condition to a normal, radially expanded condition. The struts or wire segments can be formed from a shape memory material, such as a nickel titanium alloy (e.g., Nitinol™). Further, the stent frame can be laser-cut from a single piece of material, or can be assembled from a number of discrete components. 
         [0031]    One simplified, non-limiting example of a prosthetic valve  100  is illustrated in  FIG. 3 . As a point of reference, the prosthetic valve  100  is shown in a normal or expanded state in the view of  FIG. 3 . The prosthetic valve  100  includes a stent or stent frame  102  and a valve structure  104 . The stent frame  102  can assume any of the forms mentioned above, and is generally constructed to be self-expandable from the compressed state to the normal, expanded state. 
         [0032]    The valve structure  104  of the prosthetic valve  100  can assume a variety of forms, and can be formed, for example, from one or more biocompatible synthetic materials, synthetic polymers, autograft tissue, homograft tissue, xenograft tissue, or one or more other suitable materials. In some embodiments, the valve structure  104  can be formed, for example, from bovine, porcine, equine, ovine and/or other suitable animal tissues. In some embodiments, the valve structure  104  can be formed, for example, from heart valve tissue, pericardium, and/or other suitable tissue. In some embodiments, the valve structure  104  can include or form one or more leaflets  106 . For example, the valve structure  104  can be in the form of a tri-leaflet bovine pericardium valve, a bi-leaflet valve, or another suitable valve. 
         [0033]    In some prosthetic valve constructions, such as that of  FIG. 3 , the valve structure  104  can comprise two or three leaflets that are fastened together at enlarged lateral end regions to form commissural joints, with the unattached edges forming coaptation edges of the valve structure  104 . The leaflets  106  can be fastened to a skirt that in turn is attached to the stent frame  102 . The prosthetic valve  100  includes an outflow portion  108  corresponding to a first or outflow end  110  (forcing out fluid) of the prosthetic valve  100 . The opposite end of the prosthetic valve  100  can define an inflow portion  112  corresponding to a second or inflow end  114  (receiving fluid) of the prosthetic valve  100 . As shown, the stent frame  102  can have a lattice or cell-like structure, and optionally forms or provides posts  116  corresponding with commissures of the valve structure  104  as well as eyelets  118  (or other shapes; only a select few are labeled) at the outflow and inflow ends  110 ,  114 . If provided, the posts  116  are spaced equally around frame  102  (only one post  116  is clearly visible in  FIG. 3 ). 
         [0034]    One alternative stent frame  102 ′ is illustrated in  FIG. 4 . The stent frame  102 ′ is shown in an expanded state and has a proximal end  103   a ′ and a distal end  103   b ′ as well as a plurality of eyelets  118 ′ (only a select few are labeled) spaced equally around the stent frame  102 ′. It will be understood that the stent frame  102 ′ can be used with the valve structure  104  of  FIG. 3 . It will be understood that the valve structure  104  of  FIG. 3  can be used with the stent frame  102 ′ of  FIG. 4 . 
         [0035]      FIGS. 5A-5C  illustrate select portions of a delivery device  200  for releasably securing the prosthetic valve to an inner shaft assembly  202  of the delivery device  200  that can be substituted for the inner shaft assembly  4  (only part of the delivery device  200  is shown, see also  FIG. 1  and related disclosure; in addition, only the stent frame  102 ′ of the prosthetic valve is shown for ease of illustration). As generally illustrated in  FIG. 5A , the delivery device  200  can include a sub assembly  210  including one proximal suture  212 , one intermediate suture  216 , one distal suture  220 , a wire  230  and a release pin  240 . The sutures  212 ,  216 ,  220  are all of approximately the same length so that they compress the stent frame  102 ′ uniformly in the state of  FIG. 5A . In example embodiments, the sutures  212 ,  216 ,  220  can be threaded though eyelets  118 ′ or through stent frame  102 ′ to maintain the lateral position of the respective suture  212 ,  216 ,  220 . Each suture  212 ,  216 ,  220  includes first and second ends  214   a - b ,  218   a - b ,  222   a - b . The first end  214   a ,  218   a ,  222   a  of each of the sutures  212 ,  216 ,  220  is fixedly secured to the wire  230 , for example, by adhering the suture  212 ,  216 ,  220  to the wire  230  or tying. If the suture  212 ,  216 ,  220  is tied to the wire  230 , it may be desirable to include one or more position stabilizers  232  on the wire  230  to generally maintain the lateral position of the respective suture  212 ,  216 ,  220  on the wire  230 . Alternatively, apertures (not shown) can be formed in the wire  230  through which the sutures  212 ,  216 ,  220  can be tied. The second end  214   b ,  218   b ,  222   b  of each of the sutures  212 ,  216 ,  220  forms a loop  215 ,  219 ,  223  positioned around the release pin  240 . The sutures  212 ,  216 ,  220  are woven or otherwise disposed around the circumference of the stent frame  102 ′ and are tensioned to compress the prosthetic valve in a loaded, compressed state such that it can be delivered to the defective heart valve via the patient&#39;s vascular system. 
         [0036]    Once the sub assembly  210  is prepared, as is schematically illustrated in  FIG. 5A , the wire  230  and release pin  240  can be inserted through a slot  204  in the inner shaft assembly  202  that provides access to an interior lumen  206  of the inner shaft assembly  202  as shown in  FIG. 5B . A proximal end  234  of the wire  230  and a proximal end  242  of the release pin  240  is connected to a handle (not shown) or other actuating device, such as handle assembly  5  of  FIG. 1 , configured to actuate movement thereof within the lumen  206  of the inner shaft assembly  202 . 
         [0037]    To tension the sutures  212 ,  216 ,  220  and compress the stent frame  102 ′, the wire  230  is retracted in a proximal direction. To allow the compressed stent frame  102 ′ to expand, the wire  230  is moved distally to progressively release the tension in the sutures  212 ,  216 ,  220  thereby allowing the stent frame  102 ′ to correspondingly self-expand into its natural state. To release the sutures  212 ,  216 ,  220  from the stent frame  102 ′, the release pin  240  is pulled in the proximal direction such that the respective suture loops  215 ,  219 ,  223  disengage from the release pin  240 . The sutures  212 ,  216 ,  220  are then pulled off of the stent frame  102 ′ by proximal retraction of the wire  230 . 
         [0038]      FIG. 6  generally illustrates select components of one delivery device  300  and method for loading a prosthetic valve (only the stent frame  102 ′ of the prosthetic valve is shown for ease of illustration). The stent frame  102 ′ carries at least one suture (e.g., one proximal suture  302 , one middle  303  suture and one distal suture  304 ) that is attached to the delivery device  300  for loading and delivery of the stent frame  102 ′ to a defective heart valve. In this embodiment, the delivery device  300  controls the tension placed on the sutures  302 - 304 , which form continuous loops or bands that remain with the valve frame  102 ′ after deployment. The sutures  302 - 304  each form a loop having a diameter that is either equivalent or slightly larger than that of the prosthetic valve in its normal, expanded state. The delivery device  300  is similar to that of  FIG. 1  and includes a catheter or inner shaft assembly  306 , which can be used in place of the inner shaft assembly  4 . The catheter  306  has a first lumen  308 , a second lumen  310  and a plurality of access ports  312  fluidly in communication with the first lumen  308 . A suture actuation member  320  is slidably disposed within the first lumen  308 . The suture actuation member  320  includes a plurality of engagement sections  322 , each engagement section  322  including at least one oval-shaped tooth  324 . Alternatively, an entire length of the suture actuation member  320  can include the plurality of teeth  324 . The more teeth  324  that are provided, the greater the opportunity for capturing the sutures  302 - 304  during a prosthetic valve loading procedure. 
         [0039]    In operation, the sutures  302 - 304  can be secured through eyelets  118 ′ or around the stent frame  102 ′. The stent frame  102 ′ is threaded over the catheter  306  and positioned such that a segment of each of the sutures  302 - 304  is located within a respective one of the access ports  312 . In this way, the sutures  302 - 304  are brought into engagement with a respective one of the teeth  324  in the corresponding access port  312 . Once the sutures  302 - 304  are engaged with the suture actuation member  320 , the suture actuation member  320  can be retracted proximally within the first lumen  308  of the catheter  306  to place tension in the sutures  302 - 304 , and thus the stent frame  102 ′, to compress the stent frame  102 ′ from an expanded state into a loaded, compressed state for delivery via a patent&#39;s vasculature. Once delivered to the appropriate site, the actuation member  320  is moved distally such that tension in the sutures  302 - 304  is released, allowing the stent frame  102 ′ to self-expand. Once the captured segments of the sutures  302 - 304  are brought into alignment with the respective access port  312 , the sutures  302 - 304  disengage from respective teeth  324  to release the prosthetic valve from the delivery device  300 . Movement of the suture actuation member  320  can be controlled with a handle assembly (not shown), such as the handle assembly  5  of  FIG. 1 . In this embodiment, the maximum height of the suture actuation member  320  is almost the same as the height of the first lumen  308  to prevent accidental disengagement of the sutures  302 - 304  when the sutures  302 - 304  are engaged with the teeth  324 . While three sutures  302 - 304  are secured around the stent frame  102 ′ in  FIG. 6 , it will be understood that the number and placement of the sutures  302 - 304  can vary. 
         [0040]    Select components of a delivery device  400  utilizing the inner shaft assembly or catheter  306  and an alternate suture actuation member  420  are schematically illustrated in  FIGS. 7A-7E . The suture actuation member  420  is made of a continuous wire form material and includes a plurality of generally sinuous engagement sections  422  in between straight portions  424 . In the illustrated embodiment, the suture actuation member  420  includes three engagement sections  422 , for the engagement of three respective sutures  302 - 304  carried by the stent frame  102 ′ as described above. Alternatively, an entire length of the suture actuation member  420  includes the plurality of engagement sections  422 . Each engagement section  422  includes a V-shaped section  426  leading to a generally sinuous-shaped section  428  that is arranged and configured to retain one suture  302 - 304  within a proximally slanted U-shaped retaining element or tooth  430 . Following the generally sinuous-shaped section  428  is a ramp section  432  that leads to the following straight portion  424 . 
         [0041]    During loading of the prosthetic valve, the sutures  302 - 304  and engagement sections  422  are generally aligned with the access ports  312  in the catheter  306  such that the sutures  302 - 304  can be inserted within a respective access port  312  and engaged within one U-shaped retaining element  430  of one engagement section  422 . Once the sutures  302 - 304  are engaged, the suture actuation member  420  is retracted proximally, relative to the catheter  306  as is generally illustrated in  FIGS. 7C and 7D  to place tension in the sutures  302 - 304  and subsequently compress the stent frame  102 ′. Once the prosthetic valve is at the target site and ready for deployment, the suture actuation member  420  is pushed distally such that the tension in the sutures  302 - 304  is relieved. As the actuation member  420  is moved distally from the retracted position of  FIG. 7D  to the position of  FIG. 7C , the stent frame  102 ′ compression from the sutures  302 - 304  is progressively relieved, thus slowly allowing the stent frame  102 ′ to expand. The sutures  302 - 304  are released from the suture actuation member  420  when each suture passes the respective access port  312 . In this embodiment, the sutures  302 - 304  remain with the stent frame  102 ′ even after the catheter  306  and suture actuation member  420  are withdrawn from the patient. Movement of the suture actuation member  420  can be controlled with a handle assembly (not shown), such as handle assembly  5  of  FIG. 1 . While three sutures  302 - 304  are secured around the stent frame  102 ′ in the present embodiment, it will be understood that the number and placement of the sutures  302 - 304  can vary. 
         [0042]    Select components of yet an alternate delivery device  500  are illustrated in  FIG. 8A-8B . This delivery device  500  utilizes a suture actuation member  520  including a shaft  524  having at least one hook  534 . As with the teeth or U-shaped retaining elements of the embodiments described above, the hook  534  operates in a similar manner to engage and disengage at least one suture  302 . Suture actuation member  520  can optionally include a plurality of spaced-apart hooks for engaging multiple sutures. As with prior embodiments, movement of the suture actuation member  520  can be controlled with a handle assembly (not shown), such as handle assembly  5  of  FIG. 1 . Furthermore, the suture actuation member  520  can be positioned within or positioned alongside a catheter or inner shaft assembly, such as that disclosed with respect to prior embodiments. 
         [0043]    Although the present disclosure has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the present disclosure.