Patent Publication Number: US-2023139876-A1

Title: Mechanical guides for preferential leaflet folding during crimping

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/274,622, filed Nov. 2, 2021, the entire content of which is incorporated herein by reference. 
    
    
     FIELD 
     The present technology is generally related to prosthetic valve devices, and in particular is directed to a leaflet folding accessory for use when radially compressing the prosthetic valve device into a crimped configuration. 
     BACKGROUND 
     The human heart is a four chambered, muscular organ that provides blood circulation through the body during a cardiac cycle. The four main chambers include the right atrium and right ventricle which supplies the pulmonary circulation, and the left atrium and left ventricle which supplies oxygenated blood received from the lungs into systemic circulation. To ensure that blood flows in one direction through the heart, atrioventricular valves (tricuspid and mitral valves) are present between the junctions of the atrium and the ventricles, and semi-lunar valves (pulmonary valve and aortic valve) govern the exits of the ventricles leading to the lungs and the rest of the body. These valves contain leaflets or cusps that open and shut in response to blood pressure changes caused by the contraction and relaxation of the heart chambers. The valve leaflets move apart from each other to open and allow blood to flow downstream of the valve, and coapt to close and prevent backflow or regurgitation in an upstream manner. 
     Diseases associated with heart valves, such as those caused by damage or a defect, can include stenosis and valvular insufficiency or regurgitation. For example, valvular stenosis causes the valve to become narrowed and hardened which can prevent blood flow to a downstream heart chamber from occurring at the proper flow rate and may cause the heart to work harder to pump the blood through the diseased valve. Valvular insufficiency or regurgitation occurs when the valve does not close completely, allowing blood to flow backwards, thereby causing the heart to be less efficient. A diseased or damaged valve, which can be congenital, age-related, drug-induced, or in some instances, caused by infection, can result in an enlarged, thickened heart that loses elasticity and efficiency. Some symptoms of heart valve diseases can include weakness, shortness of breath, dizziness, fainting, palpitations, anemia and edema, and blood clots which can increase the likelihood of stroke or pulmonary embolism. Symptoms can often be severe enough to be debilitating and/or life threatening. 
     Heart valve prostheses have been developed for repair and replacement of diseased and/or damaged heart valves. Such heart valve prostheses can be percutaneously delivered and deployed at the site of the diseased heart valve through catheter-based delivery systems. Such heart valve prostheses are delivered in a radially compressed or crimped configuration so that the heart valve prosthesis can be advanced through the patient&#39;s vasculature. Once positioned at the treatment site, the heart valve prosthesis is expanded to engage tissue at the diseased heart valve region to, for instance, hold the heart valve prosthesis in position. 
     The present disclosure relates to improvements in radially compressing or crimping a heart valve prosthesis to ensure that the heart valve prosthesis has a low profile for transcatheter delivery through a patient&#39;s vasculature and further to ensure that the leaflets of the heart valve prosthesis are not damaged during crimping. 
     SUMMARY 
     According to a first embodiment hereof, the present disclosure provides an assembly including a transcatheter valve prosthesis and a leaflet folding accessory. The transcatheter valve prosthesis includes a frame and a prosthetic valve component including at least one leaflet disposed within and secured to the frame. The transcatheter valve prosthesis has an expanded configuration and a crimped configuration for delivery within a vasculature. The leaflet folding accessory is configured for use when compressing the transcatheter valve prosthesis into the crimped configuration. The leaflet folding accessory includes a plurality of guide fingers. A leaflet contact portion of each guide finger is configured to be disposed radially within the frame and contact an inner surface of a leaflet of the at least one leaflet. During crimping of the transcatheter valve prosthesis, the plurality of guide fingers are configured to remain disposed radially within the frame such that the at least one leaflet preferentially folds around the plurality of guide fingers. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers include at least three guide fingers. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers include exactly three guide fingers and the prosthetic valve component includes exactly three leaflets. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers are configured so as to not directly contact an outer surface of the at least one leaflet. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides each guide finger is formed of a pliable polymer material. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers are circumferentially spaced apart from each other. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet folding accessory includes a handle configured to be held by a user. The handle is attached to a first end of each guide finger. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet folding accessory further includes a collar disposed over the handle. The collar is moveable relative to the guide fingers in order to adjust a radial position of the leaflet contact portions of the guide fingers. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that each guide finger includes an outward bump formed on a midportion thereof, the outward bump extending radially outward and being configured to interact with the collar. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet contact portion of each guide finger is a curved end portion. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that each guide finger is a rod having a substantially circular cross section. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that each guide finger tapers from a first end to a second end thereof, the first end having a greater diameter than the second end. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that each guide finger has a flattened, ribbon-like cross section. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet folding accessory includes a handle configured to be held by a user and wherein a first end of each guide finger is attached to a nut, the nut being removably attached to an end of the handle. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the assembly further includes a valve seat locator configured to receive an end of the transcatheter valve prosthesis. The valve seat locator is configured to align the leaflet contact portion of each guide finger with a midline of the at least one leaflet. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet folding accessory includes a hub. The hub is attached to a first end of each guide finger, and a second end of each guide finger is unconstrained. In an embodiment, the hub includes a plurality of slots formed on an outer surface thereof, each slot being configured to receive one of the guide fingers of the plurality of guide fingers. The slots permit only radial movement of the guide fingers during crimping of the transcatheter valve prosthesis. In an embodiment, the leaflet folding accessory also includes a slotted tubular component extending axially from the hub and includes a plurality of second slots on an outer surface thereof, each second slot being configured to receive one of the guide fingers of the plurality of guide fingers. The guide fingers radially collapse into the second slots during crimping of the transcatheter valve prosthesis. 
     In an aspect of the first embodiment, and in combination with any other aspects herein, the disclosure provides that a first end of each guide finger is attached to a first hub and a second end of each guide finger is attached to a second hub. The second hub includes a lumen longitudinally extending therethrough such that the second hub is configured to be slide relative to an outer surface of a delivery system. 
     According to a second embodiment hereof, the present disclosure provides a method of crimping a transcatheter valve prosthesis onto a delivery system. A leaflet folding accessory is positioned at least partially within a transcatheter valve prosthesis. The leaflet folding accessory includes a plurality of guide fingers, each guide finger having a leaflet contact portion. The transcatheter valve prosthesis includes a frame and a prosthetic valve component including at least one leaflet disposed within and secured to the frame. The transcatheter valve prosthesis is in an expanded configuration, and the leaflet folding accessory is positioned such that the leaflet contact portion of each guide finger is disposed radially within the frame and contacts an inner surface of a leaflet of the at least one leaflet. A crimper is positioned over the transcatheter valve prosthesis in the expanded configuration. A delivery system is positioned through a central lumen of the transcatheter valve prosthesis. The crimper is operated to compress the transcatheter valve prosthesis into at least a partially crimped configuration, and the leaflet folding accessory remains positioned such that each guide finger is disposed radially within the frame such that the at least one leaflet preferentially folds around the plurality of guide fingers. The leaflet folding accessory from is removed within the transcatheter valve prosthesis after the step of operating the crimper to compress the transcatheter valve prosthesis into at least the partially crimped configuration. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides the step of operating the crimper to compress the transcatheter valve prosthesis into a fully crimped configuration after the step of removing the leaflet folding accessory from within the transcatheter valve prosthesis. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides the step of twisting the leaflet folding tool prior to the step of removing the leaflet folding accessory from within the transcatheter valve prosthesis. The step of twisting the leaflet folding tool may occur during or after the step of operating the crimper to compress the transcatheter valve prosthesis into at least the partially crimped configuration. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides the step of positioning a leaflet folding accessory at least partially within a transcatheter valve prosthesis includes aligning each guide finger with a midline of a leaflet of the at least one leaflet. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the frame includes a plurality of commissure posts and a plurality of axial struts, each axial strut being circumferentially disposed between a pair of commissure posts. The midline of the at least one leaflet is aligned with an axial strut of the plurality of axial struts. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the step of positioning a leaflet folding accessory at least partially within a transcatheter valve prosthesis includes deflecting the leaflet contact portion of the guide fingers radially inwards. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet contact portion of the guide fingers are deflected radially inwards by rotating a collar to advance the collar relative to the guide fingers. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the step of positioning a leaflet folding accessory at least partially within a transcatheter valve prosthesis includes positioning an end of the transcatheter valve prosthesis into a valve seat locator such that each guide finger aligns with a midline of a leaflet of the at least one leaflet. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers include at least three guide fingers. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers include exactly three guide fingers and the prosthetic valve component includes exactly three leaflets. The step of positioning a leaflet folding accessory at least partially within a transcatheter valve prosthesis includes positioning one guide finger to contact a single leaflet. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers do not directly contact an outer surface of the at least one leaflet during the step of operating the crimper to compress the transcatheter valve prosthesis into at least the partially crimped configuration. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides each guide finger is formed of a pliable polymer material. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the plurality of guide fingers are circumferentially spaced apart from each other. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet folding accessory includes a handle configured to be held by a user, the handle being attached to a first end of each guide finger. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet contact portion of each guide finger is a curved end portion. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides each guide finger is a rod having a substantially circular cross section. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that each guide finger tapers from a first end to a second end thereof, the first end having a greater diameter than the second end. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that each guide finger has a flattened, ribbon-like cross section. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the leaflet folding accessory includes a hub, the hub being attached to a first end of each guide finger, and a second end of each guide finger is unconstrained. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides that the hub includes a plurality of slots formed on an outer surface thereof, each slot being configured to receive one of the guide fingers of the plurality of guide fingers. The slots permit only radial movement of the guide fingers during the step of operating the crimper to compress the transcatheter valve prosthesis into at least the partially crimped configuration. In an embodiment, the leaflet folding accessory also includes a slotted tubular component extending axially from the hub and includes a plurality of second slots on an outer surface thereof, each second slot being configured to receive one of the guide fingers of the plurality of guide fingers. The guide fingers radially collapse into the second slots during the step of operating the crimper to compress the transcatheter valve prosthesis into at least the partially crimped configuration. 
     In an aspect of the second embodiment, and in combination with any other aspects herein, the disclosure provides a first end of each guide finger is attached to a first hub and a second end of each guide finger is attached to a second hub. The second hub includes a lumen longitudinally extending therethrough such that the second hub is configured to be slide relative to an outer surface of a delivery system. 
     The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The foregoing and other features and advantages of the invention will be apparent from the following description of embodiments thereof as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. The drawings are not to scale. 
         FIG.  1 A  depicts a side view of a transcatheter valve prosthesis according to embodiments thereof. 
         FIG.  1 B  depicts a top view of the transcatheter valve prosthesis of  FIG.  1 A . 
         FIG.  2    depicts a perspective view of a leaflet folding accessory according to an embodiment hereof, wherein guide fingers of the leaflet folding accessory are in a leaflet contact configuration. 
         FIG.  3    depicts a sectional side view of the leaflet folding accessory of  FIG.  2   , wherein guide fingers of the leaflet folding accessory are in the leaflet contact configuration. 
         FIG.  4    depicts a perspective view of the leaflet folding accessory of  FIG.  2   , wherein guide fingers of the leaflet folding accessory are in the leaflet contact configuration and a collar of the leaflet folding accessory is removed for sake of illustration only. 
         FIG.  5    depicts a perspective view of the collar of the leaflet folding accessory of  FIG.  2   , wherein the collar is shown removed from the leaflet folding accessory of  FIG.  2    for sake of illustration only. 
         FIG.  5 A  is a sectional view of the collar of  FIG.  5   , taken along line A-A of  FIG.  5   . 
         FIG.  6    depicts a perspective exploded view of a leaflet folding accessory according to another embodiment hereof, wherein guide fingers of the leaflet folding accessory are in the leaflet contact configuration and a collar of the leaflet folding accessory is removed for sake of illustration only, and wherein the guide fingers are configured to be removably coupled to a hub of the leaflet folding accessory. 
         FIG.  7    is a side view of a guide finger of the leaflet folding accessory of  FIG.  2   , wherein the guide finger is shown removed from the leaflet folding accessory of  FIG.  2    for sake of illustration only. 
         FIG.  7 A  is a side view of a guide finger according to another embodiment hereof, wherein the guide finger is shown removed from a leaflet folding accessory for sake of illustration only. 
         FIG.  7 B  is a side view of a guide finger according to another embodiment hereof, wherein the guide finger is shown removed from a leaflet folding accessory for sake of illustration only. 
         FIG.  7 C  is a side view of a guide finger according to another embodiment hereof, wherein the guide finger is shown removed from a leaflet folding accessory for sake of illustration only. 
         FIG.  7 D  is a side view of a guide finger according to another embodiment hereof, wherein the guide finger is shown removed from a leaflet folding accessory for sake of illustration only. 
         FIG.  7 E  is a side view of a guide finger according to another embodiment hereof, wherein the guide finger is shown removed from a leaflet folding accessory for sake of illustration only. 
         FIG.  8    depicts a schematic side view of an assembly according to embodiments thereof, the assembly including a crimper, the leaflet folding accessory of  FIG.  2   , and a delivery system, wherein the transcatheter valve prosthesis of  FIG.  1    is disposed within a crimper chamber of the crimper and the leaflet folding accessory is disposed radially within the transcatheter valve prosthesis via an inflow end thereof. 
         FIG.  9    depicts a schematic side view of an assembly according to embodiments thereof, the assembly including a crimper having a crimper chamber, a leaflet folding accessory according to another embodiment hereof, and a delivery system, wherein the transcatheter valve prosthesis of  FIG.  1    is disposed within a crimper chamber of the crimper and the leaflet folding accessory is disposed radially within the transcatheter valve prosthesis via an outflow end thereof. 
         FIG.  10    depicts a method of using the leaflet folding accessory of  FIG.  2    within the assembly of  FIG.  8    according to an embodiment hereof. 
         FIG.  11    depicts an end view of the crimper chamber of  FIG.  8   , wherein the transcatheter valve prosthesis is in a radially expanded configuration. 
         FIG.  12    depicts an end view of the crimper chamber of  FIG.  8   , wherein the transcatheter valve prosthesis is in a partially crimped configuration. 
         FIG.  13    depicts a method of using the leaflet folding accessory of  FIG.  2    within the assembly of  FIG.  8    according to another embodiment hereof. 
         FIG.  14    depicts an end view of the crimper chamber of  FIG.  8   , wherein the transcatheter valve prosthesis is in a partially crimped configuration after the step of twisting of leaflet folding accessory of the method of  FIG.  13   . 
         FIG.  15    depicts a perspective view of a valve seat locator according to an embodiment hereof, wherein the valve seat locator is configured to be used when positioning the leaflet folding accessory of  FIG.  2    within the transcatheter valve prosthesis of  FIG.  1   . 
         FIG.  16    depicts a perspective view of a valve seat locator according to another embodiment hereof, wherein the valve seat locator is configured to be used when positioning the leaflet folding accessory of  FIG.  2    within the transcatheter valve prosthesis of  FIG.  1   . 
         FIG.  17    depicts a perspective view of a valve seat locator according to another embodiment hereof, wherein the valve seat locator is configured to be used when positioning the leaflet folding accessory of  FIG.  2    within the transcatheter valve prosthesis of  FIG.  1   . 
         FIG.  18    depicts a schematic perspective view of an assembly according to another embodiment thereof, the assembly including a crimper having a crimper chamber, a leaflet folding accessory according to another embodiment hereof, and a delivery system, wherein the leaflet folding accessory is also configured to receive a distal end of the delivery system to provide longitudinal and circumferential centering of the delivery system within the crimper chamber. 
         FIG.  19    depicts a perspective view of a leaflet folding accessory in accordance with another aspect of the disclosure, wherein guide fingers of the leaflet folding accessory are in a leaflet contact configuration and a hub of the leaflet folding accessory includes a plurality of slots for controlled movement of the guide fingers during use of the leaflet folding accessory. 
         FIG.  20    depicts a perspective view of the leaflet folding accessory of  FIG.  19   , wherein the guide fingers of the leaflet folding accessory are radially collapsed. 
         FIG.  21    depicts a side view of a leaflet folding accessory in accordance with another aspect of the disclosure, wherein guide fingers of the leaflet folding accessory are in a leaflet contact configuration and each guide fingers is constrained on opposing ends thereof. 
         FIG.  22    depicts a side view of the leaflet folding accessory of  FIG.  21   , wherein the guide fingers of the leaflet folding accessory are radially collapsed. 
         FIG.  23    depicts an exploded perspective view of a leaflet folding accessory according to another embodiment hereof, wherein guide fingers of the leaflet folding accessory are in a leaflet contact configuration and wherein the leaflet folding accessory includes an alternative handle configuration. 
         FIG.  24    depicts a perspective view of a leaflet folding accessory according to another embodiment hereof, wherein guide fingers of the leaflet folding accessory are in a leaflet contact configuration and wherein the leaflet folding accessory includes a slidable collar. 
         FIG.  25    depicts a perspective view of the leaflet folding accessory of  FIG.  24   , wherein the slidable collar and a second concentric portion of a handle are shown in phantom. 
         FIG.  26    depicts a perspective view of the slidable collar of the leaflet folding accessory of  FIG.  24   , wherein the slidable collar is shown removed from the leaflet folding accessory for sake of illustration only. 
         FIG.  27    depicts a perspective view of a first concentric portion of the handle of the leaflet folding accessory of  FIG.  24   , wherein the first concentric portion is shown removed from the leaflet folding accessory for sake of illustration only. 
     
    
    
     DETAILED DESCRIPTION 
     Specific embodiments of the present invention are now described with reference to the figures, wherein like reference numbers indicate identical or functionally similar elements. The terms “inflow” and “outflow”, when used in the following description to refer to a native vessel, native valve, or a device to be implanted into a native vessel or native valve, such as a transcatheter valve prosthesis, are with reference to the direction of blood flow. 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. 
     The following detailed description is merely exemplary in nature and is not intended to limit the invention of the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding field of the invention, background, summary or the following detailed description. 
     Embodiments hereof relate to a leaflet folding accessory or tool configured for use with a transcatheter valve prosthesis when radially compressing the transcatheter valve prosthesis from an expanded configuration into a crimped configuration for delivery within a vasculature. The folding pattern of the leaflets when the transcatheter valve prosthesis is in the crimped configuration determines the distribution of stresses and strains in the leaflets. During crimping of the transcatheter valve prosthesis, the crimping may cause leaflet damage and/or the leaflets may fold into an irregular pattern that adversely affects the profile of the transcatheter valve prosthesis in the crimped configuration. Embodiments of the leaflet folding accessory described herein are configured to guide or control folding of the leaflets of the transcatheter valve prosthesis during crimping, thereby preventing undesirable folding and/or damage to the leaflets during crimping. The leaflets preferentially fold in a pre-determined and desirable pattern which results in a smaller delivery profile of the transcatheter valve prosthesis for delivery. As a result, the leaflet folding accessories described herein increase the packing efficiency of the transcatheter valve prosthesis. The leaflet folding accessory tool is removed after the transcatheter valve prosthesis is partially crimped or fully crimped but before the transcatheter valve prosthesis is delivered within a vasculature. 
       FIGS.  1 A and  1 B  illustrate a transcatheter valve prosthesis  100  that may be utilized with the embodiments of the crimping accessory described herein. The transcatheter valve prosthesis  100  is illustrated herein in order to facilitate description of the present invention. The following description of the transcatheter valve prosthesis  100  is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. It is understood that any number of alternate heart valve prostheses can be used with the leaflet accessory tools and methods described herein. Other non-limiting examples of transcatheter valve prostheses that can be used with the leaflet accessory tools described herein are described in U.S. patent application Ser. No. 17/186,485, filed Feb. 26, 2021, which is incorporated by reference herein in its entirety. Although the transcatheter valve prosthesis  100  is a balloon-expandable heart valve prosthesis configured for placement within an aortic heart valve, embodiments of the crimping accessory described herein may be utilized with any transcatheter valve prosthesis that is crimped onto a delivery system. For example, embodiments of the leaflet folding accessory described herein may be utilized with a transcatheter heart valve configured for placement within a pulmonary, aortic, mitral, or tricuspid valve, or may be utilized with a transcatheter valve prosthesis configured for placement within a venous valve or within other body passageways where it is deemed useful. Embodiments of the leaflet folding accessory described herein may be utilized with a self-expanding transcatheter valve prosthesis or a balloon-expandable transcatheter valve prosthesis. There is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
       FIGS.  1 A and  1 B  illustrate side and top views, respectively, of the transcatheter valve prosthesis  100 . The transcatheter valve prosthesis  100  includes a radially-expandable frame  102  and a prosthetic valve component  104 . The frame  102  of the transcatheter valve prosthesis  100  is a unitary frame or scaffold that supports the valve component  104  within the interior of the frame  102 . In an embodiment, the frame  102  is balloon-expandable. The valve component  104  includes at least one leaflet  105  disposed within and secured to the frame  102 . In an embodiment, the valve component  104  of the transcatheter valve prosthesis  100  includes exactly three leaflets  105 , as shown in  FIG.  1 B . The valve component  104  of the transcatheter valve prosthesis  100  is capable of blocking flow in one direction to regulate flow there-through via the valve leaflets  105 . The transcatheter valve prosthesis  100  has a crimped configuration for delivery within a vasculature and an expanded configuration (as shown in  FIGS.  1 A and  1 B ) for deployment within a native heart valve. 
     The frame  102  includes an inflow portion  106 A, an outflow portion  106 C, and a transition portion  106 B bridging, connecting, or otherwise extending between the inflow portion  106 A and the outflow portion  106 C. The inflow portion  106 A includes a plurality of crowns  110 A and a plurality of struts  108 A with each crown  110 A being formed between a pair of opposing struts  108 A. Each crown  110 A is a curved segment or bend extending between opposing struts  108 A. The inflow portion  106 A is tubular, with a plurality of side openings  112 A being defined by the plurality of crowns  110 A and the plurality of struts  108 A. In an embodiment, the plurality of side openings  112 A may be diamond-shaped. 
     The outflow portion  106 C includes a plurality of crowns  110 C and a plurality of struts  108 C with each crown  110 C being formed between a pair of opposing struts  108 C. Each crown  110 C is a curved segment or bend extending between opposing struts  108 C. The outflow portion  106 C can be configured in a shape that forms a central lumen or passageway, for example, a ring. 
     The transition portion  106 B bridges, connects, or otherwise extends between the inflow portion  106 A and the outflow portion  106 C. The transition portion  106 B includes a total of six axial frame members  114 , each axial frame member  114  extending between a crown  110 C of the outflow portion  106 C and a crown  110 A of the inflow portion  106 A. The axial frame members  114  are substantially parallel to the central longitudinal axis of the frame  102 . Three of the six axial frame members  114  are commissure posts  114 A and aligned with and attached to a respective commissure of the three leaflets  105  of the valve component  104 . Three of the axial frame members  114  are axial struts  114 B and are disposed between adjacent commissure posts  114 A such that the axial struts  114 B and the commissure posts  114 A alternate around a circumference of the frame  102 . 
     The frame  102  includes a plurality of endmost outflow side openings or cells  112 B. The endmost outflow side openings  112 B of the outflow portion  106 C are relatively larger than the plurality of side openings  112 A of the inflow portion  106 A to improve access to the coronary arteries. More particularly, the endmost outflow side openings  112 B of the outflow portion  106 C are configured to be of sufficient size to be easily crossed with a coronary guide catheter into either the right coronary artery or the left main coronary artery once the transcatheter heart valve  100  is deployed in situ. 
     The valve component  104  of the transcatheter valve prosthesis  100  is capable of regulating flow therethrough via valve leaflets  105  that may form a replacement valve.  FIGS.  1 A and  1 B  illustrate an exemplary valve component  104  having three leaflets  105 , although a single leaflet or bicuspid leaflet configuration may alternatively be used in embodiments hereof.  FIG.  1 A  depicts a side view of the transcatheter valve prosthesis  100 , with the valve component  104  being shown disposed within and secured to the frame  102  of the heart valve prosthesis  100 .  FIG.  1 B  depicts an atrial or inflow end view of the transcatheter valve prosthesis  100 . When deployed in situ, the valve component  104  in a closed state is configured to block blood flow in one direction to regulate blood flow through a central lumen  116  of the frame  102  of the transcatheter valve prosthesis  100 . The valve component  104  includes three valve leaflets  105  that open during diastole. 
     The frame  102  is configured to secure the valve component  104  within the central lumen  116  of the frame  102  and to secure the transcatheter valve prosthesis  100  in place in the vasculature of the patient. The three leaflets  105  of the valve component  104  are attached to the frame  102  along a margin of attachment  117  that follows struts  108 A and nodes  118  of the inflow portion  106 A of the frame  102 . A node  118  is defined as a region where two crowns of the plurality of crowns  110 A within the inflow portion  106 A connect. 
     The valve component  104  further includes a graft material or skirt  119  which encloses or lines the inflow portion  106 A of the frame  102  as would be known to one of ordinary skill in the art of prosthetic tissue valve construction, for example, using sutures or a suitable biocompatible adhesive. The leaflets  105  are attached to the skirt  119 . Leaflets  105  are sutured or otherwise securely and sealingly attached along their bases to the interior surface of the skirt  119 , or otherwise attached to the frame  102 . Adjoining pairs of leaflets are attached to one another at their lateral ends to form commissures, with free edges of the leaflets  105  forming coaptation edges that meet in a closed configuration. The orientation of the leaflets  105  within the valve component  104  depends upon on which end of the transcatheter valve prosthesis  100  is the inflow end and which end of the transcatheter valve prosthesis  100  is the outflow end, thereby ensuring one-way flow of blood through the transcatheter valve prosthesis  100 . 
     The valve leaflets  105  and the skirt  119  may be formed of various flexible materials including, but not limited to natural pericardial material such as tissue from bovine, equine or porcine origins, or synthetic materials such as polytetrafluoroethylene (PTFE), DACRON® polyester, pyrolytic carbon, or other biocompatible materials. With certain prosthetic leaflet materials, it may be desirable to coat one or both sides of the replacement valve leaflet with a material that will prevent or minimize overgrowth. It is further desirable that the prosthetic leaflet material is durable and not subject to stretching, deforming, or fatigue. 
     A crimper may be used to radially compress the transcatheter valve prosthesis  100  from an expanded configuration to a crimped configuration on a balloon of a delivery system for delivery within a vasculature. During the crimping process, the leaflets  105  of the valve component  104  may protrude or extend through the side openings  112 B of the frame  102 , and, as a result, become pinched therein. This may lead to damage of the leaflets  105 , such as splitting, peeling, experiencing partial or full cuts, or separation of the layers of material. Each of these types of damages is considered unacceptable and may render the entire transcatheter valve prosthesis defective. Further, even if the leaflets  105  are not damaged as described above, they may still extend through the side openings  112 B of the frame  102  resulting in the leaflets  105  protruding radially outside of the frame  102 . If protruded, the leaflets  105  may extend radially far enough to exceed the profile tolerance of the transcatheter valve prosthesis  100 , which may undesirably increase a crossing profile of the transcatheter valve prosthesis  100 . Therefore, there exists a need to ensure the valve component  104  is maintained within the frame  102  during the crimping process. 
       FIG.  2    depicts a perspective view of a leaflet folding accessory  220  according to an embodiment hereof. The leaflet folding accessory  220  is a mechanical guide or tool that is configured for use with a transcatheter valve prosthesis (such as but not limited to the transcatheter valve prosthesis  100 ) when radially compressing the transcatheter valve prosthesis into a crimped configuration for delivery within a vasculature. For illustrative purposes only, the leaflet folding accessory  220  will be described for use with the transcatheter valve prosthesis  100  since the structure thereof has been described herein. 
     The leaflet folding accessory  220  includes a plurality of guide fingers  222 , a hub or handle  230 , and a rotatable collar  232 . In  FIG.  2   , the guide fingers  222  are depicted in a leaflet contact configuration in which a leaflet contact portion  223  of each guide finger  222  is configured and sized to be disposed radially within the frame  102  of the transcatheter valve prosthesis  100  and contact an inner surface of the leaflets  105 . During crimping of the transcatheter valve prosthesis  100 , the plurality of guide fingers  222  remain disposed radially within the frame  102  such that the leaflets  105  of the valve component  104  preferentially fold around the plurality of guide fingers  222 . The leaflet contact portion  223  of each guide finger  222  holds at least a portion of a leaflet  105  of the transcatheter valve prosthesis  100  directly adjacent to or against an inner surface of the frame  105  of the transcatheter valve prosthesis  100  when the transcatheter valve prosthesis  100  is compressed into the crimped configuration. The guide fingers  222  are configured to contact only the inner surfaces of the leaflets  105  of the valve component  104 . Stated another way, all of the guide fingers  222  are radially disposed entirely within the leaflets  105  of the valve component  104  and are configured such that the guide fingers  222  do not directly contact the outer surface of the leaflets  105  and do not directly contact the frame  102  of the transcatheter valve prosthesis  100 . 
     As the transcatheter valve prosthesis  100  is crimped into a radially compressed configuration, the plurality of guide fingers  222  hold the leaflets  105  against an inner surface of the frame  105  of the transcatheter valve prosthesis  100  in order to cause the leaflets  105  to preferentially fold around the guide fingers  222 . Stated another way, due to the presence of the guide fingers  222 , the leaflets  105  fold into a predetermined pattern during crimping of the transcatheter valve prosthesis  100  which prevents any leaflet damage and/or irregular folding patterns that adversely affect the delivery profile of the transcatheter valve prosthesis  100 . More particularly, without leaflet folding accessory  220 , the leaflets  105  may fold inwards at different rates and thereby result in folding into an irregular pattern. For example, a single leaflet  105  may drop or fold prior to the remaining leaflet(s)  105  and such an inconsistent sequence may result in crimping the initially folded leaflet  105  more than the other leaflet(s)  105 . Such different folding rates of the leaflets  105  may result in damage of the initially folded leaflet  105 . However, when all the leaflets  105  are held in a defined pattern via the plurality of guide fingers  222 , each leaflet  105  folds at a consistent rate and in a consistent pattern with each other leaflet  105 , thereby allowing more packing of the leaflet material without damaging any leaflet. 
     In an embodiment, the plurality of guide fingers  222  cause the leaflets  105  to fold into a predetermined pattern that includes alternating folds or pleats (i.e., infolds and outfolds) that form around the plurality of guide fingers  222  during crimping. The predetermined pleated pattern of the leaflets  105  enables a smaller delivery profile or diameter of the transcatheter valve prosthesis  100  in the crimped configuration, and further the predetermined pleated pattern includes a controlled distribution of stresses and strains in the leaflets  105 . The pleats or folds may be uniform in size and shape, or in another embodiment, the pleats may not be uniform in size and/or shape. 
     As stated above, the main components of the leaflet folding accessory  220  include the plurality of guide fingers  222 , the handle  230 , and the collar  232 .  FIG.  3    depicts a sectional side view of the leaflet folding accessory  220 , while  FIG.  4    depicts a perspective view of the leaflet folding accessory  220  in which the collar  232  of the leaflet folding accessory  220  is removed for sake of illustration only.  FIG.  5    depicts a perspective view of the collar  232  and  FIG.  5 A  is a sectional view taken along line A-A of  FIG.  5   . In an embodiment, when the guide fingers are in the leaflet contact configuration depicted in  FIGS.  2 ,  3 , and  4   , each guide finger  222  extends from the handle  230  axially and substantially parallel to a longitudinal axis of the handle  230 , and axially and substantially parallel to a longitudinal axis of the transcatheter valve prosthesis  100  when in use. Each guide finger  222  includes a first end  224  that is attached to the handle  230  and a second end  226  that is spaced apart from the handle  230 . The second end  226  of each guide finger  222  is unconstrained, i.e., is free or detached from any other structure. The leaflet contact portion  223  is formed closer to the second end  226  of each guide finger  222  than the first end  228 . The length of the leaflet contact portion  223  depends upon the size of the transcatheter valve prosthesis  100  being crimped. 
     The plurality of guide fingers  222  are circumferentially spaced apart from each other. The plurality of guide fingers  222  include at least three guide fingers. As shown in the embodiment of  FIGS.  2 - 6   , the plurality of guide fingers  222  may include exactly three guide fingers  222 , with each guide finger  222  being configured to contact a single leaflet  105  of the valve component  104 . However, in another embodiment, the plurality of guide fingers  222  may include more than three guide fingers. The number of guide fingers  222  may depend on the number of leaflets  105  and/or the size and configuration of the frame  102 . For example, the plurality of guide fingers  222  may include six guide fingers  222 , with two guide fingers  222  being configured to contact a single leaflet  105  of the valve component  104 . When configured for use with a valve component having single leaflet or bicuspid leaflet configuration, the number of guide fingers  222  configured to contact each leaflet may vary from the tricuspid leaflet configuration. When the leaflet accessory tool  220  includes exactly three guide fingers  222 , and the transcatheter valve prosthesis  100  includes exactly three leaflets, the guide fingers  222  are circumferentially spaced apart from each other at substantially equal intervals with a single guide finger being positioned to contact a single leaflet. If the leaflet accessory tool  220  includes exactly six guide fingers  222 , and the transcatheter valve prosthesis  100  includes exactly three leaflets, the guide fingers  222  are circumferentially spaced apart from each other with two guide fingers being positioned to contact a single leaflet. The two guide fingers would be positioned between commissure posts  114 A of the frame  102  to form substantially equal intervals between the commissure posts  114 A and each guide finger. 
     The handle  230  is configured to be hand-held by a user in order to position the leaflet folding accessory  220  as desired during the crimping process of the transcatheter valve prosthesis  100 . The handle  230  includes a first longitudinal portion  234 A and a second longitudinal portion  234 B. The second longitudinal portion  234 B has a smaller outer diameter than the first longitudinal portion  234 A, and includes a first threaded surface  236  having a first plurality of threads formed or disposed on an outer surface thereof. The collar  232  is disposed over the second longitudinal portion  234 B of the handle  230 , and is configured to rotate relative thereto. More particularly, the collar  232  includes a second threaded surface  238  having a second plurality of threads formed on an inner surface thereof. The threads of the first threaded surface  236  are configured to mate with the threads of the second threaded surface  238 . 
     The collar  232  is rotatable relative to the handle  230  in order to adjust a radial position of the leaflet contact portions  223  of the guide fingers  222 . More particularly, the leaflet contact portions  223  of the guide fingers  222  may be radially compressed for easy insertion into the transcatheter valve prosthesis  100 . After the guide fingers  222  are in the correct longitudinal position within the transcatheter valve prosthesis  100 , the guide fingers  222  may be radially expanded to resume the leaflet contact configuration and thereby contact the leaflets  105  such that each guide finger  222  is positioned to hold at least a portion of a leaflet  105  of the transcatheter valve prosthesis  100  directly adjacent to or against an inner surface of the frame  105  of the transcatheter valve prosthesis  100 . When the collar  232  is rotated in a first direction, i.e., counter clockwise or clockwise depending on the direction of the threads, the collar  232  moves in a longitudinal direction indicated by directional arrow  240  (shown on  FIG.  2   ) towards the leaflet contact portions  223  of the guide fingers  222  due to the interaction between the mating first and second threaded surface  236 ,  238 . As the collar  232  moves towards the leaflet contact portions  223  of the guide fingers  222 , the collar  232  moves into contact with the outward bumps  242  formed on the guide fingers  222 . More particularly, each guide finger  222  includes an outward bump  242  formed on a mid-portion thereof between the leaflet contact portion  223  and the first end  224 . The outward bumps  242  extend radially outward relative to the remaining length of the guide finger  222 , and are configured to interact with the collar  232 . As the collar  232  is advanced over the outward bumps  242 , the leaflet contact portions  223  of the guide fingers  222  are deflected or moved radially inward as indicated by directional arrows  244 . When deflected radially inwards, the leaflet contact portions  223  may be easily positioned into the frame  102  of the transcatheter valve prosthesis  100 . Once positioned as desired, a user may rotate the collar  232  in a second direction that opposes the first direction, i.e., the other of counter clockwise or clockwise, to cause the collar  232  to move back to its initial longitudinal position and permit the guide fingers  222  to resume or revert to their initial radial positions of the leaflet contact configuration. 
     Although the leaflet folding accessory  220  is described herein as including the collar  232 , in another embodiment hereof, the collar  232  and the second longitudinal portion  234 B of the handle  230  may be omitted. The guide fingers  222  may alternatively be displaced or deflected by hand (i.e., by a user) when positioning the leaflet folding accessory  220  into the transcatheter valve prosthesis  100 . Further, additional configurations of the handle and collar are described in more detail herein with respect to  FIGS.  23 - 27   . 
     In another embodiment depicted in  FIG.  6   , guide fingers  622  are configured to be removably coupled to a handle  630  of a leaflet folding accessory  620 . More particularly, a first end  624  of each guide finger  622  is attached to a nut  645  and the nut  645  is removably attached to an end  646  of the handle  630 . The nut  645  includes a plurality of protrusions  647  that are configured to be received within a plurality of holes  648  formed on the end  646  of the handle  630 . The protrusions  647  are configured to be received within the holes  648 , and snap-fit features may be molded on the protrusions  647  and/or the holes  648  such that the protrusions  647  are disposed within the holes  648  via a snap fit or friction fit connection. In another embodiment, the subassembly of the guide fingers  622  and the nut  645  may be attached to the handle  630  via adhesive. The size of the guide fingers  622  may vary depending on the size of the transcatheter valve prosthesis  100 . Thus, the size of the guide fingers  622  on the leaflet folding accessory  620  is customizable to tailor the leaflet folding accessory  620  to the size of the transcatheter valve prosthesis  100 . Manufacturability of the leaflet folding accessory  620  is improved by forming the guide fingers  622  separately from the handle  630 . In addition, during assembly of the leaflet folding accessory  620 , the rotatable collar  232  may be threaded onto the handle  630  prior to coupling the subassembly of the guide fingers  622  and the nut  645  to the handle  630  so that the guide fingers  622  do not undergo plastic deformation by passing the rotatable collar  232  thereover during assembly. 
     Turning now to  FIG.  7   , the contour or profile of a guide finger  222 ,  622  will be described in more detail.  FIG.  7    is a side view of a guide finger  222  of the leaflet folding accessory  220 , with the guide finger  222  being shown removed from the leaflet folding accessory  220  for sake of illustration only. The guide finger  222  is a rod having a substantially circular cross section along an entire length thereof. A diameter of the guide finger  222  tapers from the first end  224  to the second end  226  thereof. Stated another way, the first end  224  of the guide finger  222  has a first diameter D 1  which is greater than a second diameter D 2  of the second end  226  of the guide finger  222 . As such, the strength of the guide finger is relatively greater at the first end  224  thereof, which is attached to the handle  630 , while the flexibility of the guide finger  622  is relatively greater at the second end  226  thereof. The increased flexibility of the second end  226  permits the guide finger  622  to easily bend or flex during crimping of the transcatheter valve prosthesis  100 . 
     As used herein, “substantially” circular cross section includes rods that have a portion thereof ovalized. In an embodiment, at least the first ends  224  of the guide fingers  222  are ovalized to inhibit circumferential displacement when the rotatable collar  232  is twisted to compress or release the guide fingers  222 . By optimizing the major diameter in the circumferential direction for stability and minimizing the minor diameter in the radial direction at the first ends  224 , a degree of flexure in the radial direction is enabled so that second ends  226  of the guide fingers  222  may flex inward to permit insertion to the transcatheter valve prosthesis  100  without damaging the leaflets  105 . In another embodiment, the first ends  224  of the guide fingers  222  are ovalized with the major diameter in the circumferential direction and the second ends  226  of the guide fingers  222  are ovalized with the major diameter in the radial direction. By doing so the second ends  226  of the guide fingers  222  can maintain sufficient radial force while allowing void space for folding of the leaflets  105  when the transcatheter valve prosthesis  100  is crimped. 
     Each guide finger  222  is formed of a pliable polymer material. The polymer material of the plurality of guide fingers  222  must have sufficient stiffness to hold the leaflets  105  of the transcatheter valve prosthesis  100  in the open state when the transcatheter valve prosthesis  100  is compressed into the crimped configuration, but must also be configured to contact the leaflets  105  of the transcatheter valve prosthesis  100  without causing damage thereto. Suitable polymer materials for the plurality of guide fingers  222  include but are not limited to ePTFE, polyurethane, silicone, Acetal, Delrin, nylon, or stainless steel wire. In another embodiment, each guide finger  222  is a composite finger comprised of a metal core for stiffness and a polymer layer or coating disposed over the metal core for friction modulation. In another embodiment, each guide finger  222  is formed from a soft foam such that the guide fingers collapse while the transcatheter valve prosthesis  100  is crimped, yet still influences or guides the folding behavior of the leaflets during collapse. 
     Although shown with a tapered profile, it will be apparent to one of ordinary skill in the art that the guide fingers  222  may have alternative profiles, contours, or geometries.  FIGS.  7 A- 7 D  illustrate alternative guide finger profiles that are configured for contacting an inside surface of a leaflet  105 .  FIG.  7 A  is a side view of a guide finger  722 A according to another embodiment hereof, with the guide finger  722 A being shown removed from a leaflet folding accessory for sake of illustration only. The guide finger  722 A includes a curved leaflet contact portion  723 A adjacent to a second end  726  thereof. The curved leaflet contact portion  723 A provides an atraumatic surface geometry for contacting an inside surface of a leaflet  105 .  FIG.  7 B  is a side view of a guide finger  722 B according to another embodiment hereof, with the guide finger  722 B being shown removed from a leaflet folding accessory for sake of illustration only. The guide finger  722 B is a rod having a substantially circular cross section along an entire length thereof and a diameter of the guide finger  722 B is constant from a first end  724 B to a second end  726 B thereof. Thus, the guide finger  722 B is similar to the guide finger  222  except that the guide finger  722 B does not include a taper along a length thereof.  FIG.  7 C  is a side view of a guide finger  722 C according to another embodiment hereof, with the guide finger  722 C being shown removed from a leaflet folding accessory for sake of illustration only. The guide finger  722 C has a flattened, ribbon-like cross section along an entire length thereof. The flattened, ribbon-like cross section of the guide finger  722 D provides an atraumatic surface geometry for contacting an inside surface of a leaflet  105 .  FIG.  7 D  is a side view of a guide finger  722 D according to another embodiment hereof, with the guide finger  722 D being shown removed from a leaflet folding accessory for sake of illustration only. The guide finger  722 D has a curved cross section along an entire length thereof. The curved cross section of the guide finger  722 D provides an atraumatic surface geometry for contacting an inside surface of a leaflet  105 . In addition, the curved inner surface of the guide finger  722 D may be configured to mate with an outer surface of a component of the delivery system, such as the balloon of the delivery system or an outward bumper that is disposed at an end of the balloon of the delivery system. 
       FIG.  7 E  is a side view of a guide finger  722 E according to another embodiment hereof, with the guide finger  722 E being shown removed from a leaflet folding accessory for sake of illustration only. Similar to the guide finger  222 , the guide finger  722 E is a rod having a substantially circular cross section along an entire length thereof and a diameter of the guide finger  722 E tapers from the first end  724 E to the second end  726 E thereof. In addition, similar to the guide finger  222 , each guide finger  722 E includes an outward bump  742 E formed on a mid-portion thereof between a leaflet contact portion  723 E and the first end  724 E. The outward bump  742 E extend radially outward relative to the remaining length of the guide finger  722 E, and are configured to interact with the collar  232 . However, unlike the guide finger  222 , the guide finger  722 E also includes an inward bump  743 E formed directly adjacent to the outward bump  742 E, between the outward bump  742 E and the leaflet contact portion  723 E. The inward bump  743 E extends in an opposing directing that the outward bump  742 E, and thus extends radially inward relative to the remaining length of the guide finger  722 E. Collectively, the inward bump  743 E and the outward bump  742 E form an S-shape or profile. The inward bump  743 E functions as a stop that prohibits plastic deformation of the guide fingers  722 E when they are compressed for insertion into the transcatheter valve prosthesis  100 . More particularly, when radially compressed for insertion into the transcatheter valve prosthesis  100 , the inward bumps  743 E of the guide fingers  722 E contact or abut against each other so that the guide fingers  722 E cannot be over-compressed to a point in which plastic deformation of the guide fingers  722 E would occur. The inward bump  743 E keeps the guide fingers  722 E from deflecting excessively and permanently deforming. Further, the angled straight section of the guide finger  722 E between the inward bump  743 E and the leaflet contact portion  723 E minimizes contact with the inflow edge of the frame  102  of the transcatheter valve prosthesis  100  while maximizing contact of the second end  726 E of the guide finger  722  at the edge of the leaflet  105 . 
     With the structure of the leaflet folding accessory  220  described in detail above, methods of using the leaflet folding accessory  220  will now be described with references to  FIGS.  8 - 13   .  FIG.  8    depicts a schematic illustration of an assembly including a crimper  850 , the leaflet folding accessory  220 , and a delivery system  854 . In the embodiment of  FIG.  8   , the leaflet folding accessory  220  is disposed radially within the transcatheter valve prosthesis  100  via the inflow portion  106 A thereof. An exemplary delivery system including an expandable balloon for radially expanding the transcatheter valve prosthesis  100  is described in U.S. application Ser. No. 16/907,466, filed Jun. 22, 2021, or U.S. application Ser. No. 17/406,618, filed Aug. 19, 2021, each of which is herein incorporated by reference in its entirety. However, it will be apparent to one of ordinary skill in the art that other delivery systems may be utilized and that the components of the delivery system may vary depending upon the configuration and structure of the transcatheter valve prosthesis that is being delivered. The crimper  850  may be any mechanical crimping device known in the art that is configured to radially compress the transcatheter valve prosthesis  100  from its expanded configuration to a radially compressed configuration suitable for intravascular delivery as known in the art. For example, the crimper  850  may be, for example, a crimper described in U.S. patent application Ser. No. 17/394,025, filed Aug. 4, 2021, herein incorporated by reference in its entirety. 
     As shown in  FIG.  8   , the leaflet folding accessory  220  is configured to be disposed adjacent to a distal end or tip of the delivery system  854 . The transcatheter valve prosthesis  100  is disposed or positioned within a crimper chamber  852  of the crimper  850  with the inflow portion  106 A thereof disposed closer to the distal end of the delivery system  854  than the outflow portion  106 C thereof. As such, during crimping of the transcatheter valve prosthesis  100 , the guide fingers  222  extend through the central lumen  116  of the transcatheter valve prosthesis  100  from the inflow portion  106 A thereof. 
     However, it will be understood by one of ordinary skill in the art that the leaflet folding accessory  220  may be modified such that it is configured to slide or otherwise be disposed over the delivery system  854 . In such an embodiment, during crimping of the transcatheter valve prosthesis  100 , the guide fingers may extend through the central lumen  116  of the transcatheter valve prosthesis  100  from the outflow portion  106 C thereof. More particularly,  FIG.  9    depicts a schematic illustration of an assembly including the crimper  850 , a leaflet folding accessory  920 , and the delivery system  854 . The transcatheter valve prosthesis  100  is disposed or positioned within the crimper chamber  852  of the crimper  850  with the inflow portion  106 A thereof disposed closer to the distal end of the delivery system  854  than the outflow portion  106 C thereof, and the leaflet folding accessory  920  is disposed radially within the transcatheter valve prosthesis  100  via the outflow portion  106 C thereof. The leaflet folding accessory  920  is similar to the leaflet folding accessory  220 , except that a handle  930  thereof includes a lumen or passageway  955  longitudinally extending therethrough such that the leaflet folding accessory  920  may be advanced over and slide relative to an outer surface of the delivery system  854 . 
       FIG.  10    depicts method steps according to an embodiment hereof for using the leaflet folding accessory  220  during crimping of the transcatheter valve prosthesis  100  onto the delivery system  854 . Although the method steps are described herein with reference to the leaflet folding accessory  220 , the same method steps may be performed by the leaflet folding accessory  620 , the leaflet folding accessory  920 , the leaflet folding accessory  1920 , or the leaflet folding accessory  2120 . 
     With reference to step  1060  of  FIG.  10   , with the transcatheter valve prosthesis  100  in its expanded configuration, the leaflet folding accessory  220  is positioned through the central lumen  116  of the transcatheter valve prosthesis  100  such that the guide fingers  222  are disposed radially within the leaflets  105 . In an embodiment, the step  1060  may include actuating or advancing the rotatable collar  232  of the leaflet folding accessory  220  so that the second ends  226  of the guide fingers  222  are deflected radially inwards until the contact each other. While in this radially compressed configuration, the guide fingers  222  may be inserted into the transcatheter valve prosthesis  100 . In an embodiment, the guide fingers  222  are inserted into the inflow portion  106 A of the transcatheter valve prosthesis  100 . The plurality of guide fingers  222  of the leaflet folding accessory  220  are advanced until the leaflet contact portions  223  of the guide fingers  222  are disposed as desired longitudinally relative to the transcatheter valve prosthesis  100 . In an embodiment, the plurality of guide fingers  222  of the leaflet folding accessory  220  are advanced until the leaflet contact portions  223  of the guide fingers  222  are disposed with the second ends  226  beyond or past the free edges of the leaflets  105  between 3 mm and 5 mm. The guide fingers  222  may be positioned such that each guide finger  222  is substantially aligned with a midline of a leaflet  105 . A midline of a leaflet  105  is disposed equally or midway between the respective commissures of the leaflet. Aligning the guide fingers  222  with the midlines of the leaflets  105  results in the most preferential folding of the leaflets  105  because the amount of leaflet material is equally distributed around a guide finger  222 . In addition, with respect to the particular structure of the transcatheter valve prosthesis  100 , the midlines of the leaflets  105  are disposed adjacent to the axial struts  114 B of the frame  102 . Thus, when the guide fingers  222  are aligned with the midlines of the leaflets  105 , each guide finger  222  is further disposed adjacent to the axial struts  114 B (with material of a leaflet  105  disposed therebetween), such that the guide fingers  222  are supported during the crimping operation. The material of the leaflets  105  is essentially pinned or sandwiched between an axial strut  114 B and a guide finger  222  in order to result in preferential folding of the material of the leaflets  105  between the axial struts  114 B and the commissure posts  114 A. The presence and location of the guide fingers  222  prevent the leaflets  105  from folding into an irregular pattern. 
     It will be understood by one of ordinary skill in the art that placement of the guide fingers  222  is not limited to the midlines of the leaflets  105 . The placement of the guide fingers  222  depends on a number of factors including the size of the leaflets  105 , the number of guide fingers of the leaflet folding accessory, and the number or placement of axial struts  114 B of the frame  102 . 
     After the guide fingers  222  are in the correct longitudinal and circumferential position within the transcatheter valve prosthesis  100 , the guide fingers  7222  may be radially expanded to resume the leaflet contact configuration and thereby contact the leaflets  105  such that each guide finger  222  is positioned to hold at least a portion of a leaflet  105  of the transcatheter valve prosthesis  100  directly adjacent to or against an inner surface of the frame  105  of the transcatheter valve prosthesis  100 . More particularly, the collar  232  is rotated or otherwise caused to move back to its initial longitudinal position and permit the guide fingers  222  to resume or revert to their initial radial positions of the leaflet contact configuration. In an embodiment, once in the leaflet contact configuration, the second ends  226  of the guide fingers  222  extend uniformly between 3 mm and 5 mm beyond or past the free edges of the leaflets  105 . 
     With reference to step  1061  of  FIG.  10   , the subassembly of the leaflet folding accessory  220  and the transcatheter valve prosthesis  100  is positioned into the crimper chamber  852  of the crimper  850 . It will be understood by one of ordinary skill in the art that the subassembly of the leaflet folding accessory  220  and the transcatheter valve prosthesis  100  may be advanced into the crimper chamber  852  or the crimper  850  may be positioned around the transcatheter valve prosthesis  100  such that the crimper  850  circumferentially surrounds the transcatheter valve prosthesis  100 . 
     With reference to step  1062  of  FIG.  10   , as well as  FIG.  11   , the delivery system  854  is positioned through the subassembly of the transcatheter valve prosthesis  100  and the leaflet folding accessory  220 . The delivery system  854  is advanced through the crimper  850  until the balloon of the delivery system  854  is disposed as desired longitudinally relative to the transcatheter valve prosthesis  100 .  FIG.  11    depicts an end view of the crimper chamber  852 , with the subassembly of the transcatheter valve prosthesis  100  and the leaflet folding accessory  220  disposed therein, and the delivery system  854  disposed therethrough. The transcatheter valve prosthesis  100  is in a radially expanded configuration, and each guide fingers  222  is substantially aligned with a midline of a leaflet  105  as described above. 
     With reference to step  1063  of  FIG.  10   , as well as  FIG.  12   , the crimper  850  is operated to radially compress the transcatheter valve prosthesis  100  to a partially crimped configuration onto the balloon of the delivery system  854 . During operation of the crimper  850 , the leaflet folding accessory  220  remains positioned or disposed radially within the leaflets  105  of the transcatheter valve prosthesis  100 , with the leaflet contact portion  223  of each guide finger  220  contacting and holding the leaflets  105  of the transcatheter valve prosthesis  100  against the axial struts  114 B of the frame  102 . As described above, by pinning or sandwiching the material of the leaflets between an axial strut  114 B and a guide finger  222 , the leaflets  105  fold into a predetermined pattern during crimping of the transcatheter valve prosthesis  100  which prevents any leaflet damage and/or irregular folding patterns that adversely affect the delivery profile of the transcatheter valve prosthesis  100 . When all the leaflets  105  are held in a defined pattern via the plurality of guide fingers  222 , each leaflet  105  folds at a consistent rate and in a consistent pattern with each other leaflet  105 , thereby allowing more packing of the leaflet material without damaging any leaflet. This preferentially folded pattern of the leaflets  105  result in a smaller delivery profile or diameter of the transcatheter valve prosthesis  100  in the crimped configuration, and further the predetermined folded pattern includes a controlled distribution of stresses and strains in the leaflets  105  which minimizes the risk of leaflet damage. 
       FIG.  12    depicts an end view of the crimper chamber  852 , with the subassembly of the transcatheter valve prosthesis  100  and the leaflet folding accessory  220  disposed therein, and the delivery system  854  disposed therethrough. The transcatheter valve prosthesis  100  is in a partially crimped configuration. Each guide finger  222  is substantially aligned with a midline of a leaflet  105 , and the material of the leaflets  105  extending between the axial struts  114 B and the commissure posts  114 A is folded in a radially inward direction. The material of the leaflets  105  that is folded in a radially inward direction may be considered an infold, and the material of the leaflets  105  disposed between the guide fingers  222  and the frame  102  may be considered an outfold such that the folded pattern includes alternating folds or pleats (i.e., infolds and outfolds). 
     The crimper  850  is configured to radially compress the transcatheter valve prosthesis  100  into a crimped configuration suitable for delivery within a vasculature. As used herein, “partially crimped” includes configurations radially compressed up to 90% of the crimped configuration suitable for delivery within a vasculature, which may also be referred to herein as a fully crimped configuration. As the crimping process nears completion and the transcatheter valve prosthesis  100  nears its fully crimped configuration, the leaflets  105  have preferentially folded as described above and therefore, the leaflet folding accessory  200  may be removed prior to completing the crimping process. Removal of the leaflet folding accessory  200  allows the transcatheter valve prosthesis  100  to be radially compressed to a smaller diameter, since the guide fingers  222  are no longer disposed radially within the transcatheter valve prosthesis. 
     With reference to step  1065  of  FIG.  10   , after the crimper  850  is operated to partially crimp the leaflet folding accessory  220  with the leaflets  105  preferentially folded as described above, the leaflet folding accessory  220  is withdrawn and removed from within the transcatheter valve prosthesis  100 . At this stage of the method, the crimper  850  is still positioned over the radially compressed transcatheter valve prosthesis  100  as shown in  FIG.  14   . After removal of the leaflet folding accessory  220 , the leaflets  105  remain folded in the predetermined pattern within the partially crimped transcatheter valve prosthesis  100 . 
     With reference to step  1066  of  FIG.  10   , after removal of the leaflet folding accessory  220 , the crimper  850  is operated to further crimp or radially compress the transcatheter valve prosthesis  100  to its fully crimped configuration, which is suitable for delivery within a vasculature. When the transcatheter valve prosthesis  100  is fully crimped, the leaflets  105  remain folded in the predetermined pattern therein. With the transcatheter valve prosthesis  100  crimped onto the balloon of the delivery system  854 , the crimper  850  may be removed. 
       FIG.  13    depicts another method of using the leaflet folding accessory  220  within the assembly of  FIG.  8   . Although the method steps are described herein with reference to the leaflet folding accessory  220 , the same method steps may be performed by the leaflet folding accessory  620 , the leaflet folding accessory  920 , or the leaflet folding accessory  2120 . Steps  1360 ,  1361 ,  1362 ,  1363 ,  1365 , and  1366  of this method are the same as steps  1160 ,  1161 ,  1162 ,  1163 ,  1165 , and  1166  of the method described in relation to  FIG.  11   . However, in this embodiment, an additional method step  1364  is included between the step  1363  and step  1365 . 
     In step  1363 , the crimper  850  is operated to radially compress the transcatheter valve prosthesis  100  to a partially crimped configuration onto the balloon of the delivery system  854 . During or after step  1363 , the leaflet folding accessory  222  may be twisted as shown in step  1364 . Twisting of the leaflet folding accessory  222  causes the guide fingers  222  to move in circumferential direction relative to the frame  102 . The guide fingers  222  move circumferentially until they abut against a commissure post  114 A of the frame  102 . The material of the leaflet  105  is disposed or folded around the guide finger  222 , and movement of the guide finger  222  also moves or displaces the leaflet folds therewith. Thus, the step of twisting the leaflet folding accessory  220  pulls the folded leaflet material circumferentially and results in a spiral folded pattern as shown in  FIG.  14   .  FIG.  14    depicts an end view of the crimper chamber  852 , with the subassembly of the transcatheter valve prosthesis  100  and the leaflet folding accessory  220  disposed therein, and the delivery system  854  disposed therethrough. The transcatheter valve prosthesis  100  is in a partially crimped configuration after the step  1363  of twisting of leaflet folding accessory  220 , and the leaflets  105  are disposed radially inwards of the frame  102  in a spiral folded pattern. 
     Although the methods of use described above with respect to  FIG.  10    and  FIG.  13    include removal of the leaflet folding accessory  220  after partial crimping of the transcatheter valve prosthesis  100 , in another embodiment hereof, the leaflet folding accessory  220  may remain disposed within the transcatheter valve prosthesis  100  for the entire crimping procedure. Stated another way, after removal of the leaflet folding accessory  220 , further crimping of the transcatheter valve prosthesis  100  is not necessarily required. The necessity for further crimping after removal of the leaflet folding accessory  220  depends upon the size of the transcatheter valve prosthesis  100  and/or the final desired crossing profile of the transcatheter valve prosthesis  100 . 
     It may be desirable to utilize a valve seat locator when performing steps  1160 ,  1360  of  FIGS.  11 ,  13   , respectively. More particularly, as previously described with respect to step  1160 , it is advantageous to position the leaflet folding accessory  220  within the transcatheter valve prosthesis  100  such that each guide finger  222  is substantially aligned with a midline of a leaflet  105 . Aligning the guide fingers  222  with the midlines of the leaflets  105  result in the most preferential folding of the leaflets because the amount of leaflet material is equally distributed around a guide finger  222 , and because the midlines of the leaflets  105  are disposed adjacent to the axial struts  114 B of the frame  102 .  FIGS.  15 - 17    depict embodiments of a valve seat locator or tool that can be utilized to align the guide fingers  222  with the midlines of the leaflets  105 . 
     More particularly,  FIG.  15    depicts a perspective view of a valve seat locator  1570  that is configured to be used when positioning the leaflet folding accessory  220  within the transcatheter valve prosthesis  100 . The valve seat locator  1570  includes an outer annular member or ring  1572 , an inner annular member or ring  1574  disposed radially within the outer ring  1572 , and a planar component  1576  disposed between the outer and inner rings  1572 ,  1574 . The planar component  1576  is undulating or wavy and includes a plurality of peaks  1582  and a plurality of valleys  1580 , with each valley  1582  formed between a pair of adjacent peaks  1582 . The frame  102  of the transcatheter valve prosthesis  100  is positioned onto the valve seat locator  1570  such that the crowns  110 C of the outflow portion  106 C of the transcatheter valve prosthesis  100  sit or are received within the valleys  1580 . Three of the peaks  1582  of the valve seat locator  1570  may include a slot  1578 . Although not shown on the embodiment of  FIG.  1   , the commissure posts  114 A may be extended towards the crowns  110 C and configured to be received within the slots  1578 . The valve seat locator  1570  further includes a protrusion  1584  formed on the outer ring  1572 . The handle  230  of the leaflet folding accessory  220  may include a protrusion thereon that is the same as or similar to the protrusion  1584 , so that the user can circumferentially align the protrusion on the handle  230  with the protrusion  1584  when positioning the leaflet folding accessory  220  relative to the transcatheter valve prosthesis. These features ensure that the transcatheter valve prosthesis  100  and the leaflet folding accessory  220  are oriented such that each guide finger  222  is substantially aligned with a midline of a leaflet  105  when the leaflet folding accessory  220  is positioned into the transcatheter valve prosthesis  100 . The valve seat locator  1570  ensures alignment of the leaflet folding accessory  220  and the transcatheter valve prosthesis  100 , because the commissure posts  114 A are inserted into the slots  1578  of the valve seat locator  1570  and the handle  230  may be aligned parallel with the protrusion  1584  formed on the outer ring  1572 , thereby ensuring that the second ends  226  of the guide fingers  222  align as desired with the midlines of the leaflets  105 . 
       FIG.  16    depicts a perspective view of another embodiment of a valve seat locator  1670  that is configured to be used when positioning the leaflet folding accessory  220  within the transcatheter valve prosthesis  100 . The valve seat locator  1670  includes an outer annular member or ring  1672 , an inner annular member or ring  1674  disposed radially within the outer ring  1672 , a plurality of bosses  1673  extending between the outer and inner rings  1672 ,  1674 , and a plurality of planar components  1676  extending between adjacent pairs of bosses  1673 . Each boss  1673  defines a slot  1678 . Although not shown on the embodiment of  FIG.  1   , the commissure posts  114 A may be extended towards the crowns  110 C and configured to be received within the slots  1678 . Each planar component  1676  is undulating or wavy and includes a peak  1682  and a pair of valleys  1680 , with the peak  1682  formed between the pair of valleys  1680 . The frame  102  of the transcatheter valve prosthesis  100  is positioned onto the valve seat locator  1670  such that the crowns  110 C of the outflow portion  106 C of the transcatheter valve prosthesis  100  sit or are received within the valleys  1680 . The curvature of the planar component  1676  is configured such that the height of the peaks  1682  do not interfere with the resting position of the leaflets  105 . The valve seat locator  1670  further includes a protrusion  1684  formed on the outer ring  1672 . The handle  230  of the leaflet folding accessory  220  may include a protrusion thereon that is the same as or similar to the protrusion  1684 , so that the user can circumferentially align the protrusion on the handle  230  with the protrusion  1684  when positioning the leaflet folding accessory  220  relative to the transcatheter valve prosthesis. Further, the valve seat locator  1670  includes a D-shaped opening  1785  formed within the inner ring  1674 . The handle  230  of the leaflet folding accessory  220  may include a D-shaped opening thereon that is the same as or similar to the D-shaped opening  1785 , and a D-shaped post (not shown) may be inserted or disposed within the both of the D-shaped openings of the valve seat locator  1670  and the handle  230  to ensure correct alignment when positioning the leaflet folding accessory  220  relative to the transcatheter valve prosthesis  100 . The D-shaped openings  1785 , as well as the mating protrusions  1684 , ensure that the transcatheter valve prosthesis  100  and the leaflet folding accessory  220  are oriented such that each guide finger  222  is substantially aligned with a midline of a leaflet  105  when the leaflet folding accessory  220  is positioned into the transcatheter valve prosthesis  100 . Although the opening  1785  is described above as D-shaped, the shape thereof is not critical and any shape or configuration may be used that provides interlocking between the opening and a post inserted therein. 
       FIG.  17    depicts a perspective view of another embodiment of a valve seat locator  1770  that is configured to be used when positioning the leaflet folding accessory  220  within the transcatheter valve prosthesis  100 . The valve seat locator  1770  includes an outer annular member or ring  1772 , an inner annular member or ring  1774  disposed radially within the outer ring  1772 , a plurality of bosses  1773  extending between the outer and inner rings  1772 ,  1774 , and a pair of ramps  1787  extending from opposing sides of each boss  1773 . Each boss  1773  defines a slot  1778 . Although not shown on the embodiment of  FIG.  1   , the commissure posts  114 A may be extended towards the crowns  110 C and configured to be received within the slots  1778 . Each ramp  1787  extends in a circumferential direction from a boss  1773 , and gaps or openings  1786  are formed between adjacent ramps  1787  of adjacent bosses  1773 . Openings  1786  allow for the drainage of liquid as the transcatheter valve prosthesis  100  is positioned into the valve seat locator  1770 . The frame  102  of the transcatheter valve prosthesis  100  is positioned onto the valve seat locator  1770  such that the commissure posts  114 A are received within or at least adjacent to the slots  1778 . The ramps  1787  support the outflow portion  110 C of the transcatheter valve prosthesis  100 . The valve seat locator  1770  further includes a protrusion  1784  formed on the outer ring  1772 . The handle  230  of the leaflet folding accessory  220  may include a protrusion thereon that is the same as or similar to the protrusion  1784 , so that the user can circumferentially align the protrusion on the handle  230  with the protrusion  1784  when positioning the leaflet folding accessory  220  relative to the transcatheter valve prosthesis. Further, the valve seat locator  1670  includes a plurality of channels or grooves  1786  formed within the inner ring  1674 . The grooves  1786  are configured to receive the second ends  226  of the guide fingers  222  therein to ensure correct alignment when positioning the leaflet folding accessory  220  relative to the transcatheter valve prosthesis  100 . The grooves  1786 , as well as the mating protrusions  1784 , ensure that the transcatheter valve prosthesis  100  and the leaflet folding accessory  220  are oriented such that each guide finger  222  is substantially aligned with a midline of a leaflet  105  when the leaflet folding accessory  220  is positioned into the transcatheter valve prosthesis  100 . 
     Although the embodiments described above illustrate a hand-held leaflet folding accessory, guide fingers may be a component of a fixture that is utilized with a crimper. For example, in the embodiment of  FIG.  18   , a leaflet folding accessory  1820  having a plurality of guide fingers  1822  is a fixture.  FIG.  18    depicts a schematic perspective view of an assembly including a crimper  1850  having a crimper chamber  1852 , the leaflet folding accessory  1822 , and a delivery system  1854 . In this embodiment, in addition to including guide fingers  1822  for providing preferential folding of leaflets of a transcatheter valve prosthesis, the leaflet folding accessory  1820  is also configured to receive a distal end  1858  of the delivery system  1854  to provide longitudinal and circumferential centering of the delivery system  1854  within the crimper chamber  1852 . An exemplary delivery system including an expandable balloon for radially expanding the transcatheter valve prosthesis is described in U.S. application Ser. No. 16/907,466, filed Jun. 22, 2021, or U.S. application Ser. No. 17/406,618, filed Aug. 19, 2021, previously incorporated by reference. However, it will be apparent to one of ordinary skill in the art that other delivery systems may be utilized and that the components of the delivery system may vary depending upon the configuration and structure of the transcatheter valve prosthesis that is being delivered. The crimper  1850  may be any mechanical crimping device known in the art that is configured to radially compress a transcatheter valve prosthesis from its expanded configuration to a radially compressed configuration suitable for intravascular delivery as known in the art. For example, the crimper  1850  may be, for example, a crimper described in U.S. patent application Ser. No. 17/394,025, filed Aug. 4, 2021, herein incorporated by reference in its entirety. 
     The leaflet folding accessory  1820  includes a base  1896  that is configured to be placed on a flat surface (i.e., a table top or a floor). The base  1896  is configured to be attached to the crimper  1850  via one or more pins  1898 . The leaflet folding accessory  1820  also includes a hub  1890  that is attached to the base  1896  via an arm  1897 . The height or placement of the arm  1897  may be fixed in order to position the hub  1890  to be longitudinally and circumferentially aligned with the crimper chamber  1852  of the crimper  1850 . In another embodiment (not shown), the height or placement of the arm  1897  may be adjustable. The hub  1890  includes a recess  1892  formed on an outer surface  1894  thereof. The recess  1892  has a size and shape so as to be configured to receive the distal end  1858  of the delivery system  1854 . The size and shape of the recess  1892  may mate with the distal end  1858  of the delivery system  1854  such that undesired movement of the distal end  1858  is not permitted when the distal end  1858  is positioned into the recess  1892 . The hub  1890  functions as a stop for the distal tip  1858  of the delivery system  1854  and is longitudinally spaced apart from the crimper chamber  1852  at a predetermined distance that results in longitudinally centering of the delivery system  1854  within the crimper chamber  1852 . Particularly, the delivery system  1854  is positioned such that the transcatheter valve prosthesis is longitudinally centered between the pair of outward bumpers  1856  of the delivery system  1854 . The outward bumpers  1856  are described in more detail in U.S. application Ser. No. 17/406,618, filed Aug. 19, 2021, previously incorporated by reference. In addition, the hub  1890  is circumferentially aligned with the crimper chamber  1852  so that the delivery system  1854  is circumferentially aligned within the crimper chamber  1852  as well. 
     The plurality of guide fingers  1822  extend from the outer surface  1894  of the hub  1890 , towards the crimper chamber  1852 . In an embodiment, the guide fingers  1822  have a curved cross section along an entire length thereof as shown on guide finger  722 D described above. The curved cross section is configured to mate with an outer surface of profile of an outward bumper  1856  on the delivery system  1854 . In  FIG.  18   , the guide fingers  1822  are depicted in a leaflet contact configuration in which a leaflet contact portion of each guide finger  1822  is disposed within the crimper chamber  1852  such that the guide fingers  1822  would be disposed radially within the frame  102  of the transcatheter valve prosthesis  100  and contact an inner surface of the leaflets  105 . In the same manner as described above with respect to the guide fingers  222 , during crimping of the transcatheter valve prosthesis  100 , the plurality of guide fingers  1822  remain disposed radially within the frame  102  such that the leaflets  105  of the valve component  104  preferentially fold around the plurality of guide fingers  1822 . The guide fingers  1822  are configured to contact only the inner surfaces of the leaflets  105  of the valve component  104 . Stated another way, all of the guide fingers  1822  are radially disposed entirely within the leaflets  105  of the valve component  104  and are configured such that the guide fingers  1822  do not directly contact the outer surface of the leaflets  105  and do not directly contact the frame  102  of the transcatheter valve prosthesis  100 . 
       FIGS.  19  and  20    illustrate another example of a leaflet folding accessory  1920  that is configured to attach to a crimper (not shown in  FIGS.  19 - 20   ) during use thereof. The leaflet folding accessory  1920  is thus a removable accessory that may be attached and detached to the crimper as desired by the user.  FIG.  19    depicts a perspective view of the leaflet folding accessory  1920  with guide fingers  1922  thereof in a leaflet contact configuration while  FIG.  20    depicts a perspective view of the leaflet folding accessory  1920  with the guide fingers  1922  is a radially collapsed configuration. In this embodiment, as will be explained in more detail herein, a hub  1930  of the leaflet folding accessory  1920  is configured to attach to a crimper during use and further the hub  1930  includes a plurality of slots  1931  for controlled radial movement of the guide fingers  1922  during use of the leaflet folding accessory  1920 . 
     The leaflet folding accessory  1920  includes a plurality of guide fingers  1922 , a handle or hub  1930 , and a slotted tubular component  1933 . In  FIG.  19   , the guide fingers  1922  are depicted in a leaflet contact configuration in which a leaflet contact portion  1923  of each guide finger  1922  is configured to be disposed radially within the frame  102  of the transcatheter valve prosthesis  100  and contact an inner surface of the leaflets  105 . In the same manner as described above with respect to the guide fingers  222 , during crimping of the transcatheter valve prosthesis  100 , the plurality of guide fingers  1922  remain disposed radially within the frame  102  such that the leaflets  105  of the valve component  104  preferentially fold around the plurality of guide fingers  1922 . The guide fingers  1922  are configured to contact only the inner surfaces of the leaflets  105  of the valve component  104 . Stated another way, all of the guide fingers  1922  are radially disposed entirely within the leaflets  105  of the valve component  104  and are configured such that the guide fingers  1922  do not directly contact the outer surface of the leaflets  105  and do not directly contact the frame  102  of the transcatheter valve prosthesis  100 . 
     In an embodiment, when the guide fingers are in the leaflet contact configuration depicted in  FIG.  19   , each guide finger  1922  extends from the hub  1930  axially and radially outward relative to a longitudinal axis of the transcatheter valve prosthesis  100 , and axially and radially outward to a longitudinal axis of the hub  1930 . Each guide finger  1922  includes a first end (hidden from view in  FIG.  19   ) that is attached to the hub  1930  and a second end  1926  that is spaced apart from the hub  1930 . The second end  926  of each guide finger  1922  is unconstrained, i.e., is free or detached from any other structure. The length of the leaflet contact portion  1923  depends upon the size of the transcatheter valve prosthesis  100  being crimped. As described above with respect to the guide fingers  222 , the plurality of guide fingers  1922  include at least three guide fingers. As shown in the embodiment of  FIGS.  19 - 20   , the plurality of guide fingers  1922  may include exactly three guide fingers  1922 , with each guide finger  1922  being configured to contact a single leaflet  105  of the valve component  104 . The guide fingers  1922  may be spring-loaded or shape set into the leaflet contact configuration of  FIG.  19   . 
     The hub  1930  of the leaflet folding accessory  1920  is configured to attach to a crimper during use via a plurality of tabs  1937  which would be received within a plurality of mating slots formed on an outer surface of the crimper. When attached to the crimper, the hub  1930  is disposed outside of or external to the crimper, while the slotted tubular component  1933  and guide fingers  1922  are disposed within the crimper chamber of the crimper. The hub  1930  may attach to the crimper adjacent to the inflow portion  106 A of the transcatheter valve prosthesis  100 , or adjacent to the outflow portion  106 C of the transcatheter valve prosthesis  100 . The hub  1930  includes a lumen passageway  1955  longitudinally extending therethrough such that the leaflet folding accessory  1920  may be advanced over and relative to an outer surface of a delivery system, on either end (i.e., the outlet or the inlet) of the crimper chamber of the crimper. 
     The hub  1930  also includes the plurality of slots  1931  formed on an outer surface thereof, and the slotted tubular component  1933  extends axially from the hub  1930 . In use during crimping, the slotted tubular component  1933  is positioned over the delivery system and within the central lumen  116  of the transcatheter valve prosthesis. The slotted tubular component  1933  includes a plurality of slots  1935  circumferentially spaced apart from each other at substantially equal intervals. Each slot of the plurality of slots  1931  and each slot of the plurality of slots  1935  are each configured to receive a guide finger  1922 . The slots  1931 ,  1935  provide for controlled radial movement of the guide fingers  1922  during use of the leaflet folding accessory  1920 . Particularly, as the transcatheter valve prosthesis  100  is crimped and the guide fingers  1922  radially compress therewith during use, the radial movement of the guide fingers  1922  are controlled by slots  1931  of the hub  1930  until the guide fingers  1922  are positioned into the slots  1935  of the slotted tubular component  1933 , as shown in  FIG.  20    The guide fingers  1922  radially collapse into the slots  1935  of the slotted tubular component  1933  as the transcatheter valve prosthesis  100  is crimped by the crimper until the transcatheter valve prosthesis  100  is in a partially crimped configuration and disposed over the slotted tubular component  1933 . At this stage, the leaflet folding accessory  1920  would be removed from the crimper so that the transcatheter valve  100  may be further crimped to the fully crimped configuration onto the balloon of the delivery system. The slots  1931  of the hub  1930  permit only radial movement of the guide fingers  1922  and do not permit them to move circumferentially (i.e., side or side) during crimping of the transcatheter valve prosthesis  100 . Stated another way, the slots  1931  of the hub  1930  permit or allow the guide fingers  1922  to move only a radial direction and not in a circumferential direction. Controlling movement of the guide fingers  1922  may result in a more predictable folding pattern of the leaflets  105  of the transcatheter valve prosthesis  100 . 
       FIGS.  21  and  22    depict another embodiment of a leaflet folding accessory  2120 .  FIG.  21    depicts a perspective view of the leaflet folding accessory  2120  with guide fingers  2122  thereof in a leaflet contact configuration while  FIG.  22    depicts a perspective view of the leaflet folding accessory  2120  with the guide fingers  2122  is a radially collapsed configuration. In this embodiment, as will be explained in more detail herein, the leaflet folding accessory  2120  includes a first hub  2130 A and a second hub  2130 B. A first end  2124  of each guide finger  2122  is attached to the first hub  2130 A and a second end  2126  of each guide finger  2122  is attached to the second hub  2130 B. The second hub  2130 B includes a lumen or passageway  2156 B longitudinally extending therethrough such that the second hub  2130 B may be advanced over and relative to an outer surface of a delivery system. During use, the second hub  2130 B slides over the delivery system as the guide fingers  2120  elongate during crimping of the transcatheter valve prosthesis  100 . 
     In  FIG.  21   , the guide fingers  2122  are depicted in a leaflet contact configuration in which a leaflet contact portion  2123  of each guide finger  2122  is configured to be disposed radially within the frame  102  of the transcatheter valve prosthesis  100  and contact an inner surface of the leaflets  105 . In the same manner as described above with respect to the guide fingers  222 , during crimping of the transcatheter valve prosthesis  100 , the plurality of guide fingers  2122  remain disposed radially within the frame  102  such that the leaflets  105  of the valve component  104  preferentially fold around the plurality of guide fingers  2122 . The guide fingers  2122  are configured to contact only the inner surfaces of the leaflets  105  of the valve component  104 . Stated another way, all of the guide fingers  2122  are radially disposed entirely within the leaflets  105  of the valve component  104  and are configured such that the guide fingers  2122  do not directly contact the outer surface of the leaflets  105  and do not directly contact the frame  102  of the transcatheter valve prosthesis  100 . 
     When the guide fingers are in the leaflet contact configuration depicted in  FIG.  21   , each guide finger  2122  has a curved configuration with the first end  2124  of each guide finger  2122  being attached to the first hub  2130 A and the second end  2126  of each guide finger  2122  is attached to the second hub  2130 B. The guide fingers  2122  may be spring-loaded or shape set into the leaflet contact configuration of  FIG.  21   , with the leaflet contact portions  2123  forming a generally flat plateau of the curved configuration. The length of the leaflet contact portion  2123  depends upon the size of the transcatheter valve prosthesis  100  being crimped. As described above with respect to the guide fingers  222 , the plurality of guide fingers  2122  include at least three guide fingers. As shown in the embodiment of  FIG.  21   , the plurality of guide fingers  2122  may include exactly three guide fingers  2122 , with each guide finger  2122  being configured to contact a single leaflet  105  of the valve component  104 . 
     During use, the first hub  2130 A is positioned adjacent to the inflow portion  106 A of the transcatheter valve prosthesis  100  within a crimper chamber of a crimper, and the second hub  2130 B is positioned adjacent to the outflow portion  106 C of the transcatheter valve prosthesis  100  within the crimper chamber of the crimper. The second hub  2130 B is positioned over the delivery system via the lumen  2156 B, and is configured to slide relative thereto. Particularly, as the transcatheter valve prosthesis  100  is crimped and the guide fingers  2122  radially compress therewith during use, the guide fingers  2122  elongate and second hub  2130 B as a result moves in a direction towards the handle of the delivery system, as indicated by directional arrow  2241 , until the guide fingers  2122  are substantially straightened as shown in  FIG.  22    and the transcatheter valve prosthesis  100  is in a partially crimped configuration. At this stage, the leaflet folding accessory  2120  would be removed from the crimper so that the transcatheter valve  100  may be further crimped to the fully crimped configuration onto the balloon of the delivery system. The leaflet folding accessory  2120  may be removed from the crimper by sliding the leaflet folding accessory  2120  out of the crimper via the inflow portion  106 A of the transcatheter valve prosthesis  100 . Alternatively, the first hub  2130 A may detach from the guide fingers  2122  such that after the transcatheter valve prosthesis  100  is partially crimped, the first hub  2130 A may be detached and the guide fingers  2122  may be removed from the crimper by sliding only the guide fingers  2122  out of the crimper via the outflow portion  106 C of the transcatheter valve prosthesis  100 . 
     Although described above with only the second hub  2130 B be configured to slide over the delivery system during crimping of the transcatheter valve prosthesis  100 , the first hub  2130 A may also include a lumen of passageway formed therethrough for placement over the delivery system and the first hub  2130 A and/or the second hub  2130 B may slide relative to the delivery system as the guide fingers  2122  transform from their curved configurations of  FIG.  21    to their substantially straight configurations of  FIG.  22   . 
     The leaflet folding accessories described herein may include alternative handle configurations and are not limited to the configurations of the handle  230  and the rotatable collar  232  described above.  FIG.  23    is an exploded perspective view of a leaflet folding accessory  2320  that includes a handle  2330  and a rotatable collar  2332  according to another embodiment hereof. The leaflet folding accessory  2320  includes a plurality of guide fingers  722 E, the handle  2330 , and the rotatable collar  2332 . The guide fingers  722 E are the same as the guide finger  722 E described above. In  FIG.  23   , the guide fingers  722 E are depicted in a leaflet contact configuration in which a leaflet contact portion of each guide finger  722 E is configured and sized to be disposed radially within the frame  102  of the transcatheter valve prosthesis  100  and contact an inner surface of the leaflets  105 . Each guide finger  722 E extends from the handle  2330  axially and substantially parallel to a longitudinal axis of the handle  2330 , and axially and substantially parallel to a longitudinal axis of the transcatheter valve prosthesis  100  when in use. 
     The handle  2330  is configured to be hand-held by a user in order to position the leaflet folding accessory  2320  as desired during the crimping process of the transcatheter valve prosthesis  100 . The handle  2330  includes a first concentric portion  2330 A and a second concentric portion  2330 B. The first concentric portion  2330 A includes a first threaded surface  2336  having a first plurality of threads formed or disposed on an outer surface thereof. The second concentric portion  2330 B includes a second threaded surface  2338  having a second plurality of threads formed on an inner surface thereof. The threads of the first threaded surface  2336  are configured to mate with the threads of the second threaded surface  2338 . When assembled, the second concentric portion  2330 B is disposed over the first concentric portion  2330 A and secured to the first concentric portion  2330 A via a fastener  2330 C. Via the fastener  2330 C, the first concentric portion  2330 A and the second concentric portion  2330 B are attached or secured to each other such that relative rotation therebetween is not permitted. Stated another way, the fastener  2330 C, the first concentric portion  2330 A and the second concentric portion  2330 B form a subassembly and no relative movement is permitted once assembled together. 
     The collar  2332  is also configured to be disposed over the first concentric portion  2330 A of the handle  2330  after assembly. More particularly, the collar  2332  also includes the second threaded surface  2338 . As described above, the second threaded surface  2338  has a second plurality of threads formed on an inner surface thereof that are configured to mate with the threads of the first threaded surface  2386 . Once assembled onto the handle  2330 , the collar  2332  is disposed closer to the guide fingers  722 E than the second concentric portion  2330 B. After assembly onto the handle  2330 , the collar  2332  is configured to rotate relative to the handle  2330 , or more specifically, to the first concentric portion  2330 A of the handle  2330 . 
     The collar  2332  is rotatable relative to the handle  2330  in order to adjust a radial position of the leaflet contact portions of the guide fingers  722 E. More particularly, the leaflet contact portions of the guide fingers  722 E may be radially compressed for easy insertion into the transcatheter valve prosthesis  100 . After the guide fingers  722 E are in the correct longitudinal position within the transcatheter valve prosthesis  100 , the guide fingers  722 E may be radially expanded to resume the leaflet contact configuration and thereby contact the leaflets  105  such that each guide finger  722 E is positioned to hold at least a portion of a leaflet  105  of the transcatheter valve prosthesis  100  directly adjacent to or against an inner surface of the frame  105  of the transcatheter valve prosthesis  100 . When the collar  2332  is rotated in a first direction, i.e., counter clockwise or clockwise depending on the direction of the threads, the collar  2332  moves in a longitudinal direction towards the guide fingers  722 E due to the interaction between the mating first and second threaded surface  2336 ,  2338 . As the collar  2332  moves longitudinally, the collar  2332  moves into contact with the outward bumps  742 E formed on the guide fingers  722 E and the leaflet contact portions of the guide fingers  722 E are deflected or moved radially inward. When deflected radially inwards, the leaflet contact portions may be easily positioned into the frame  102  of the transcatheter valve prosthesis  100 . Once positioned as desired, a user may rotate the collar  2332  in a second direction that opposes the first direction, i.e., the other of counter clockwise or clockwise, to cause the collar  2332  to move back to its initial longitudinal position and permit the guide fingers  722 E to resume or revert to their initial radial positions of the leaflet contact configuration. 
     Advantageously, for the embodiment of  FIG.  23   , assembly of the components of the leaflet folding accessory  2320  does not require the guide fingers  722 E to be radially compressed. More particularly, the rotatable collar  2332  and the second concentric portion  2330 B can be threaded onto the first concentric portion  2330 A from the end opposite from the guide fingers  722 E. As such, the guide fingers  722 E do not need to be compressed during assembly and can remain in their leaflet contact configuration during assembly of the rotatable collar  2332  and the second concentric portion  2330 B onto the first concentric portion  2330 A. 
     An alternative handle embodiment which utilizes a slidable collar rather than a rotatable collar is depicted in  FIGS.  24 - 27   . In some instances, a slidable collar may be preferred over a rotatable collar due to ergonomic considerations and/or personal user preference.  FIG.  24    is a perspective view of a leaflet folding accessory  2420  that includes a slidable collar  2432  according to another embodiment hereof. The leaflet folding accessory  2420  includes a plurality of guide fingers  722 E, a handle  2430 , and the slidable collar  2432 . The guide fingers  722 E are the same as the guide finger  722 E described above. In  FIG.  24   , the guide fingers  722 E are depicted in a leaflet contact configuration in which a leaflet contact portion of each guide finger  722 E is configured and sized to be disposed radially within the frame  102  of the transcatheter valve prosthesis  100  and contact an inner surface of the leaflets  105 . Each guide finger  722 E extends from the handle  2430  axially and substantially parallel to a longitudinal axis of the handle  2430 , and axially and substantially parallel to a longitudinal axis of the transcatheter valve prosthesis  100  when in use. 
     The handle  2430  is configured to be hand-held by a user in order to position the leaflet folding accessory  2420  as desired during the crimping process of the transcatheter valve prosthesis  100 . The handle  2430  includes a first concentric portion  2430 A and a second concentric portion  2430 B. The first concentric portion  2430 A of the handle  2430  includes at least one elongated channel or groove  2425  formed or disposed on an outer surface thereof. Although obscured from view, in this embodiment, the first concentric portion  2430 A includes three grooves  2425  equally spaced around a circumference of the first concentric portion  2430 A. With additional reference to  FIG.  27   , each elongated channel or groove  2425  includes a first longitudinal portion  2425 A and a second longitudinal portion  2425 B in which the size of the groove is smaller or reduced. A stepped surface  2425 C is formed between the first and second longitudinal portions  2425 A,  2425 B. The second concentric portion  2430 B of the handle  2430  includes at least one elongated rib  2427  formed on an inner surface thereof. Although obscured from view, in this embodiment, the second concentric portion  2430 B includes three ribs  2427  equally spaced around the inner circumferential surface thereof. Each elongated rib  2427  is configured or sized to be received within the first longitudinal portion  2425 A of the groove  2425  such that that the second concentric portion  2430 B may slide over the first concentric portion  2430 A during assembly. When assembled, the second concentric portion  2430 B is disposed over the first concentric portion  2430 A and secured to the first concentric portion  2430 A via a fastener  2430 C. Via the fastener  2430 C, the first concentric portion  2430 A and the second concentric portion  2430 B are attached or secured to each other such that relative rotation therebetween is not permitted. Stated another way, the fastener  2430 C, the first concentric portion  2430 A and the second concentric portion  2430 B form a subassembly and no relative movement is permitted once assembled together. 
     The collar  2432  is also configured to be disposed over the first concentric portion  2430 A of the handle  2430  after assembly. More particularly, with additional reference to  FIG.  26   , the collar  2432  includes at least one elongated rib  2421  formed on an inner surface thereof. In this embodiment, the collar  2432  includes three ribs  2421  equally spaced around the inner circumferential surface thereof. The elongated rib  2421  includes a flange  2427 A at an end thereof in which the size of the rib is increased. More particularly, the size or configuration of the flange  2427 A is the same as the size or configuration of the elongated rib  2427  of the second concentric portion  2340 B. Except for the flange  2427 A, the elongated rib  2421  is configured or sized to be received within the second longitudinal portion  2425 B of the groove  2425 . Once assembled onto the handle  2430 , the collar  2432  is disposed closer to the guide fingers  722 E than the second concentric portion  2430 B. After assembly onto the handle  2430 , the collar  2432  is configured to slide or move axially/longitudinally relative to the handle  2430 , or more specifically, to the first concentric portion  2430 A of the handle  2430 . 
     The collar  2432  is slidable relative to the handle  2430  in order to adjust a radial position of the leaflet contact portions of the guide fingers  722 E. More particularly, the leaflet contact portions of the guide fingers  722 E may be radially compressed for easy insertion into the transcatheter valve prosthesis  100 . After the guide fingers  722 E are in the correct longitudinal position within the transcatheter valve prosthesis  100 , the guide fingers  722 E may be radially expanded to resume the leaflet contact configuration and thereby contact the leaflets  105  such that each guide finger  722 E is positioned to hold at least a portion of a leaflet  105  of the transcatheter valve prosthesis  100  directly adjacent to or against an inner surface of the frame  105  of the transcatheter valve prosthesis  100 . When the collar  2432  is translated or moved in a longitudinal direction towards the guide fingers  722 E, the collar  2432  moves into contact with the outward bumps  742 E formed on the guide fingers  722 E and the leaflet contact portions of the guide fingers  722 E are deflected or moved radially inward. When deflected radially inwards, the leaflet contact portions may be easily positioned into the frame  102  of the transcatheter valve prosthesis  100 . Longitudinal translation of the collar  2432  is limited by interaction between the flange  2427 A of the collar  2432  and the stepped surface  2425 C of the groove  2425 . More particularly, axial or longitudinal movement of the collar  2432  in the direction towards the guide fingers  722 E is prohibited after the flange  2427 A of the collar  2432  abuts against the stepped surface  2425 C. Once the guide fingers  722 E are positioned as desired within the transcatheter valve prosthesis  100 , a user may translate or move the collar  2432  in a longitudinal direction away from the guide fingers  722 E to cause the collar  2432  to move back to its initial longitudinal position and permit the guide fingers  722 E to resume or revert to their initial radial positions of the leaflet contact configuration. 
     It should be understood that various embodiments disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the techniques).