STENT LOADING TOOL AND METHOD FOR USE THEREOF

[0001] The present invention of a device and methods generally relates to the field of cardiac medical technology. In particular, the device relates to a loading tool that may be used in crimping, loading, and delivery a stent-mounted valve or other expandable prosthetic device.

[0002] Stents are bioprosthetic devices that are typically used for counteracting restenosis, or the repeated narrowing of a blood vessel. Stents may also be used, for example, as shown in U.S. Patent Application 2006/0149360 to Schwammenthal, et al, as a component of a stent-mounted heart valve with mounted leaflets. The stent mounted valve implant described there includes clamping fingers that secure its position at a native valve orifice of the heart.

[0003] Such an implant is delivered to its site in the heart using a catheter assembly. To pass through the catheter, the prosthetic valve must be collapsed to a smaller profile. However, since the stent-mounted prosthetic valve has leaflets of pericardium material, it cannot be delivered to the hospital or medical facility in a collapsed or compressed state. Rather, the step of collapsing the implant for passage through the delivery device must be carried out shortly before the implantation procedure. Consequently, the valve, in an open state, is delivered to the user in a container and that container typically contains a sterile, preservative medium such as glutaraldehyde.

[0004] Thus, prior to the implantation procedure, the stent-mounted valve must first be manually removed from the storage medium package, collapsed (perhaps by crimping), and then loaded into the delivery catheter in that crimped state.

[0005] Several cautions are to be observed prior to and during the step of loading the stent-mounted prosthetic valve. Since the material making up the stent is easily deformed or damaged, the stent must be handled with great care. Secondly, the stent must be crimped or otherwise collapsed to the smaller profile so that it fits properly inside of the catheter delivery tube. The step of collapsing the stent is a delicate process and, if not performed properly, may cause delay the implantation procedure or may entail excessive handling of the stent or even damage to the valve. Removal of the stent from the glutaraldehyde liquid medium in the storage and delivery container by surgically-gloved surgical personnel may be awkward.

[0006] Specialized tools may be used to minimize the risks associated with preparing the stent-mounted valve for the step of implanting the prosthetic valve in the heart.

[0007] U.S. Patent Application No. 2004/0186563, to Lobbi, discloses a heart valve that is loaded into the delivery catheter using a specialized tool. The valve is crimped or collapsed to a smaller profile by pulling it through a conical-shaped region of the specialized tool. One or more filaments threaded through the valve to allow such pulling and consequent crimping of the valve. A drawback to this procedure is that the step of threading the filaments through the valve can be a tedious and time-consuming process. Also, since the filaments have no purpose after the crimping step, they must be removed from the implant prior to the delivery procedure. Removal of the filaments may cause damage to the valve and may even partially undo the crimping step.

[0008] U.S. Patent Application No. 2003/0225445 to Derus et al., describes a loading device having a conical-shaped region for facilitating the collapse of a stent. As with the Lobbi procedure, a filament or the like is used to pull the stent through the loading device to collapse it.

[0009] Other devices for transferring a stent from a storage container to a delivery tool are described in U.S. Pat. No. 6,090,035 to Campbell, U.S. Pat. No. 5,693,066 to Rupp et al., U.S. Pat. No. 6,123,720 to Anderson et al., and European Patents WO 98/22044 and WO 97/09946, both to Borghi.

[0010] None of these patents or patent applications show the device and procedures described further hereinbelow, nor do they satisfactorily solve the problems which have been described above relating to transfer of the valve from a storage device, in which the valve is in an expanded state, to the delivery tool, in which the valve is in a substantially compressed state.

[0011] There is thus a need for a tool that allows for transfer of the valve or other prosthetic device from the storage container to the catheter delivery tube, in a relatively simple manner that requires only minimal handling.

[0012] Accordingly, it is a broad object of the present invention to overcome the above-mentioned disadvantages and limitations of the prior art and provide a loading tool suitable for extracting a stent-mounted valve from its packaging, crimping that stent-mounted valve into a profile suitable for introduction into a catheter delivery tube, and loading that stent mounted valve into a catheter delivery tube in a simple and reliable manner.

[0013] The described loading and delivery tool may be configured to become a part of the delivery system once it is loaded into a catheter delivery tube. Specifically, the loading tool may join to and be considered to become a part of an inner shaft of the catheter delivery tube, and, together with the inner shaft of the catheter, cooperate to push the stent-mounted valve outward from the catheter delivery tube once the appropriate location in the heart is reached. This functionality is due to the structure (and consequent rigidity) of the loading tool. The filaments used in the crimping step of the procedures found in the Lobbi and Derus et al published applications must be removed prior to the transcatheter procedure. As noted above, the filaments serve no function during the actual implantation of the stent.

[0014] The described loading tool may be used for withdrawing, crimping, and loading a stent-mounted valve into a catheter delivery tube, and further for facilitating pushing of the stent-mounted valve from the catheter delivery tube into a native heart valve orifice.

[0015] The loading tool may be configured to connect to and to be controllably be disconnected from the stent component of the stent-mounted valve. In one such variation, the loading tool may comprise one or more connectors adapted for being removably connected to the stent of the stent-mounted valve.

[0016] The connector or connection section of the loading tool may, for instance, comprise one or more prongs. For instance, the loading tool may comprise three prongs. Where the connector comprises one or more prongs, each prong may be characterized as having a substantially rigid portion and having a less rigid hinge region. Alternatively, each prong arm may be configured so that it flexes along its length. In either case, the flexibility of the prong allows the loading tool to become part of the delivery system during the transcatheter valve placement procedure. The distal end of each prong is configured in such a way that it may be attached to the stent-mounted valve via the stent component. In turn, the stent may include sites, portions, or members to be positioned in such a way to cooperate with, and thereby be attached to, the connector or connecting section of the loading tool. In certain instances, where the design of the stent and the connector permits, the stent may have at least three connecting members positioned around its periphery for facilitating attachment to three cooperating prongs of the loading tool.

[0017] Where prongs are used as connectors to the stent, the prongs may have a variety of configurations meeting the goal of removable and controllable attachment to and separation from the stent. In one variation, each prong is formed with a radial outwardly facing notch at its distal end which cooperatively engages a conforming connector of the stent-mounted valve. In usage, the operator places the ends of the prongs over the end of the stent and compresses the prongs on the loading tool to move the notched tips of the prongs and to align each of them with a corresponding connector on the stent. The user then releases the prongs such that each individual prong becomes engaged, with a single stent connecting member.

[0018] The prongs may have notches or openings that face outwardly or that face towards the end of the tool. In each instance, suitable interfering members would be employed to allow controllable attachment of the stent to the loading tool and subsequent release of the stent from the loading tool.

[0019] The loading tool may be pre-mounted onto the stent-mounted valve and provided in packaging together with a crimping tool. The crimping tool may have a generally converging-shape allowing the user to compress the stent-mounted valve just prior to introduction into the delivery catheter by pulling it from the packaging. This combination may be provided as a kit, perhaps sterilized and perhaps including a preservative for the valve and perhaps including printed instructions for use. In other variations, the loading tool and crimping tool may be provided separately, i.e., not attached to the stent-mounted valve. However, in the latter variation, the components may also be provided as a kit perhaps with separate or integrated packaging.

[0020] The crimping tool may have a converging-shape with an open, wide end and a narrower opposing end. The step of pulling the stent-mounted valve through the converging-shape crimping tool with the loading tool causes the stent-mounted valve to become compressed, due to the decreasing diameter of the crimping tool.

[0021] Once compressed, the stent-mounted valve (perhaps after a washing step to remove preservative) may be loaded directly into the catheter delivery tube for delivery using the transcatheter procedure. The loading tool and stent may be configured so that the loading tool also grasps the stent by switching from a larger diameter (Or expanded state) to a compressed state as it is drawn through the crimping tool along with the stent-mounted valve.

[0022] The loading tool may then be attached to a control and delivery member, e.g., a inner shaft of a catheter delivery tube, and then both the loading tool and the stent-mounted valve are drawn into the catheter delivery tube. This loading tool design greatly increases the ease of transfer of the valve from the storage device to the catheter delivery tube. Also, with this loading tool, the valve is subjected to minimal handling during transfer into the catheter delivery tube, a feature which assures the integrity of the valve itself.

[0023] As noted above, in one variation of the described component prongs, each prong is provided with a notched end to engage a cooperative connecting member or site located on, e.g., around the lower periphery of, the stent. In this variation, the diameter of the open connector, is larger than the diameter of the open stent. As the prongs are slightly compressed during attachment to the stent, the opening or notch in the end of the prong envelops a complementary connection on the stent to create and retain the connection with the stent.

[0024] In another variation, at least a portion of each of the prongs is constructed of a wire form. Each of the distal ends of the prongs is configured to engage a corresponding opening, e.g., an eye-hole, in a cooperating connector located on the stent.

[0025] The loading tool may comprise one or more medically safe polymeric) metallic, or combination materials which preserve a high degree of integrity during the procedure. Suitable materials include metals or alloys such as many of the stainless steels, super-elastic alloys such as NITINOL, titanium and titanium alloys, cobalt chromium alloys, and the like. Suitable materials also include polymers such as many of the Nylons, polycarbonates, polyimides, polyketones (such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), polyetherketoneetherketoneketone (PEKEKK), and polyetheretherketoneketone (PEEKK), and generally a polyaryletheretherketone), and the like. Suitable polymeric materials, whether thermosets or thermoplastics, may be filled with, e.g., glass fibers, carbon fibers, polymeric fibers, ceramic fibers, and the like. The materials should be selected to have an elasticity allowing the loading tool to operate as described here.

[0026] The method of loading the stent mounted valve on the loading tool includes, in one variation, slightly compressing the prongs of the loading tool, inserting the prongs within the bottom of the stent-mounted valve, aligning the prongs with the stent connecting members, releasing the prongs to allow outward movement towards the stent causing the stent to become fixed into place. In this manner, the stent-mounted valve becomes connected to the loading tool and may now be drawn through the converging-shape crimping tool.

[0027] Once the stent is crimped, the loading tool is then coupled to a component of the delivery catheter assembly. The stent-mounted valve and the loading tool are then drawn into the interior of the catheter delivery tube, the converging-shape crimping tool is detached, and the stent-mounted valve and loading tool are retracted farther into the catheter delivery tube in final preparation for the transcatheter procedure.

[0028] When the stent-mounted valve is delivered during the transcatheter procedure to the native heart valve, pushing the delivery tool slightly forward within the catheter delivery tube, or holding the stent-mounted valve in place as the catheter delivery tube is moved backward, will cause the stent-mounted valve to be exposed as it is released from constriction of the catheter delivery tube. The stent-mounted valve will then self-expand into position in the native heart valve.

[0029] There is also described a system for loading a stent-mounted valve into a catheter delivery tube for performance of a transcatheter valve implantation procedure. The system may include a loading tool configured to be removably connected to the stent of a stent-mounted valve. The loading tool may be configured to be coupled to the inner shaft of a catheter delivery tube. The system may also comprise a crimping tool having a generally converging shape.

[0030] The loading tool may comprise a handle detachable from the loading tool after the crimping of the stent-mounted valve is accomplished but prior to attachment of the loading tool to the catheter. By removing the handle, the loading tool and the stent-mounted valve may then be retracted together into the catheter delivery tube.

[0031] The stent may be comprised of a wire assembly and formed with a plurality of connecting members for facilitating connection to the prongs of the loading tool. The connecting members may comprise a region of the stent (e.g., when the stent is a wire-based structure or a specific wire is added to a stent structure for the purpose of connecting to the loading tool) or may comprise members specifically provided to cooperatively attach to a prong. In one variation, the prongs each comprise a notch for facilitating connection to the connecting members or regions of the stent. In other variations, the prongs each comprise a hook-shaped member for facilitating connection to the stent

[0032] There is also described a method for withdrawing a stent-mounted valve from a storage container, crimping the stent-mounted valve, and loading the crimped stent-mounted valve into a catheter delivery tube for the performance of a transcatheter valve implantation procedure. The method includes:

[0033] (a) providing a stent-mounted valve in a substantially open state inside of a storage container;

[0034] (b) providing a loading tool comprising at least one connector adapted for being removably connected to the stent-mounted valve, and further adapted for being coupled to a inner shaft of a catheter delivery tube;

[0035] (c) providing a generally converging-shape crimping tool;

[0036] (d) attaching the loading tool to the stent-mounted valve using the at least one connector;

[0037] (e) withdrawing the stent-mounted valve from the storage container using the loading tool;

[0038] (f) pulling the stent-mounted valve through the crimping tool using the loading tool such that the stent-mounted valve becomes crimped;

[0039] (g) coupling the loading tool to the inner shaft of the catheter delivery tube, and

[0040] (h) retracting the stent-mounted valve and the loading tool into the catheter delivery tube.

[0041] Step (d) of the procedure may be performed by the stent-mounted valve manufacturer. That step may comprise a step of providing a stent-mounted valve, the connected loading tool, and the converging-shape crimping tool inside of a storage container.

[0042] The procedure may include an additional step of washing the stent-mounted valve to remove traces of the storage medium.

[0043] The stent-mounted valve and the loading tool may be configured to automatically disconnect or separate from each other upon release and expansion of the stent-mounted valve within a native heart valve orifice.

[0044] Although the described device is described with reference to a stent-mounted valve, the loading tool may be readily adapted for use with any bio-prosthetic device which is switched from a substantially open state to a substantially closed state in order to load into a catheter delivery tube.

[0045] The described loading tool need not be disconnected from the stent-mounted valve prior to delivery, as required by prior art tools and methods. Instead, the loading tool itself becomes part of the delivery system and facilitates the release of the stent-mounted valve out of the catheter delivery tube when the implantation site is reached.

[0046] Additional features and advantages of the described device will become apparent from the following drawings and description.

[0061] FIG. 1 is a perspective view of a self-expanding stent-mounted valve (20). Stent-mounted valve (20) may be of several types as is known to those skilled in the art, but in the example of FIG. 1, the stent-mounted valve (20) is shown as a wire structure having a wire-mesh, expandable frame stent (22). Engagement arms (25) are typically configured to engage and/or rest against floors of aortic sinuses, to position the prosthetic valve assembly (20) in the native valve, and to apply an axial force directed towards the left ventricle. A more detailed description of our basic stent-mounted valve is provided in U.S. patent application Ser. No. 11/024,908, filed Dec. 30, 2004, published as No. 2006/0149360, to Schwammenthal, et al., herein incorporated by reference in its entirety.

[0062] FIGS. 2 and 3 provide enlarged views of a three-prong loading tool (30) in an open state and in a closed state, respectively. The loading tool (30) has a base (32) and three prongs (34), extending therefrom for facilitating connection to the stent-mounted valve using the notches (36) found at the prong tips. Three additional short prongs (35) extend from base (32) between prongs (34). Short prongs (35) serve to secure the positioning of loading tool (30) inside of a crimping tool, in a manner to be described further below. Base (32) is provided with a pusher connector or base connectors (37) for coupling to a catheter assembly component, e.g., an inner shaft.

[0063] It is appreciated that prongs (34) in this variation should be sufficiently flexible to allow the tips to be squeezed together (as shown in FIG. 3) and allow attachment to a stent-mounted valve. The prongs (34) may have a comparatively stiff section adjacent the prong tips and a comparatively more flexible section, a hinge-like area, opposite the prong tips to allow the desired movement in attachment to the stent. Alternatively, the desired flexibility of the prongs (34) may be designed into the length of the prongs (34), i.e., each increment of a prong bends in a similar amount, thereby eliminating the hinge area of the earlier discussed variation. Other variations of prong flexibility, e.g., variation of the prong flexibility from a higher value at the tip to a lower flexibility at the base, are also suitable. Otherwise, prongs (34) should be sufficiently rigid to allow them to form a portion of the catheter delivery system.

[0064] In the variation illustrated, each prong (34) is provided with a radially outwardly facing notch (36) at its tip or distal end for connection to the stent of a stent-mounted valve such as those shown in FIG. 1. Loading tool (30) may be formed from suitable, elastic, medically safe polymeric, metallic, or combination materials which preserve a high degree of integrity during the procedure. Specifically, unless breakage or deformation is desired as a component of a particular design, the materials should not otherwise break or become deformed when in use. Suitable materials include metals or alloys such as many of the stainless steels, super-elastic alloys such as nitinol, titanium and titanium alloys, cobalt chromium alloys, and the like. Suitable materials also include polymers such as many of the Nylons, polycarbonates, polyimides, polyketones (such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), polyetherketoneetherketoneketone (PEKEKK), and polyetheretherketoneketone (PEEKK), and generally a polyaryletheretherketone), and the like. Suitable polymeric materials, whether thermosets or thermoplastics, may be filled with, e.g., glass fibers, carbon fibers, polymeric fibers, ceramic fibers, and the like.

[0065] The design specifics of the loading tool (30) may be altered from those illustrated in the drawings for connecting to the stent (22), so long as the function of the tool is preserved. For instance, in the variation shown in FIGS. 2 and 3, the loading tool (32) includes prongs (34) with notches (36) that open outwardly, the prongs switching from an open state allowing attachment to the stent, to a closed state, allowing loading into the catheter delivery tube. With appropriate modification, the notches may, however, open inwardly or be open at the end of the prongs. However, a suitable loading tool is simply one having a connector or connector region permitting controllable connection to the stent, facilitating compression (or crimping) of the stent-mounted valve, loading of the stent-mounted valve into a catheter delivery tube, and controllably releasing the stent-supported valve at the delivery site.

[0066] As mentioned above, the depicted loading tool (30) includes three prongs (34). This number of prongs (34) may be chosen as a balance between providing adequate support of the stent during the crimping step and providing the minimum number of suitably functional mechanical components. Of course, this variation of the loading tool may include any other suitable number of prongs such as, but not limited to, two, four, five or six. In each case, the stent-mounted valve would typically be provided with a corresponding number of connecting members (or connecting regions) in the stent to allow cooperative connection therebetween. For example, in variations where the loading tool has three prongs, the stent generally would also have three prongs. However, the stent may be designed to include more than three connection members, sites, or regions to ease the step of connection between the loading tool and the stent by providing additional connection sites.

[0067] FIG. 4 is an enlarged, detailed view showing the connection of the loading tool of FIGS. 2 and 3 to a stent-mounted valve. Notch (36) of prong (34) connects to the stent connector (26) of stent (22) in the manner illustrated, with connector (26) seated inside of notch (36). The stent connector (26) radially slides into notch (36). However, the notch (36) is configured so that the stent connector (26) does not substantially move axially in either direction. This configuration means that the connection is firm whether the loading tool is being used to pull the stent-mounted valve through the crimping tool or to push the crimped stent-mounted valve through the delivery catheter.

[0068] The loading tool (30) has a longitudinal axis and the at least one connector, in this case, comprising the prong(s) (34) is configured to removably attach to the stent (22) of the stent valve (20).

[0069] The depicted stent connector (26) includes an aperture (38) that is not necessary for the connection shown in FIG. 4, but may be used in conjunction with other prong variations, such as that shown in FIG. 5.

[0070] FIG. 5 is an enlarged, detailed view of an alternative connecting prong (34). In this variation, the prong (34) is provided with a hook member (42) at its distal end. The distal tip of the hook (42) passes through the aperture (38) in the stent connector (26). As is the case with prong variation discussed with regard to FIG. 3, the distal tip of the hook (42) prevents substantial, axial movement between the stent and the loading tool, but allows radial movement between the prong (34) and the stent-mounted valve during engagement and implantation of the valve.

[0071] The connection between the stent and the loading tool allows for the stent-mounted valve to be crimped and easily loaded into a catheter delivery tube, together with the loading tool. The depicted loading tools employ prongs having outward-facing notches. This means that the loading tool is placed inside the stent and the prongs grasp the stent from its interior. For those variations using a self-expanding stent, delivery of the stent-mounted valve allows the stent to undergo self-expansion. The stent expands away from the loading tool. This could be characterized as automatic disconnection of the stent from the loading tool.

[0072] FIG. 6 shows a partial cross-section of an assembly useful as a self-contained kit suitable for commercial delivery to a surgical user, e.g., a hospital, clinic, surgical suite, physician, etc. In addition to the assembly described below, additional exterior packaging and written instructions may be included as necessary or appropriate. In any case, the assembly comprises a loading tool (30) attached to (or attachable to) a stent-mounted valve (20). A generally converging-shape (or converging diameter) crimping tool (48) substantially surrounds the loading tool (30) and valve (20). These components are all included within a wide-mouthed bottle storage container (50) serving as packaging for the assembly. The crimping tool (48) may have any suitable hollow, generally converging shape that compresses the stent-mounted valve (20) as it moves through the interior of the crimping tool (48).

[0073] Stent-mounted valve (20) is shown as sitting at the bottom of bottle storage container (50). In the example illustrated, three-prong loading tool (30) is attached to stent (22) of stent-mounted valve (20), by a cooperative connection in which the stent connector (26) slides radially into notch (36) of prong (34) of loading tool (30), as shown in FIG. 4. Stent-mounted valve (20) and attached loading tool (30) are situated within converging-shape crimping tool (48). Bottle delivery or storage container (50) is filled with a sterile, non-volatile preservative, a fluid, commonly glutaraldehyde. The glutaraldehyde should be washed from the crimped components after their removal from the delivery and storage container (50).

[0074] After any exterior packaging and the top (54) are removed from storage container (50), a user (even a user wearing sterile disposable gloves) can easily remove the components from the storage container (50) by gripping the crimping tool (48) and handle (56). The handle (56) is removably connected to loading tool (30). Pulling handle (56) with respect to the crimping tool (48) draws the stent-mounted valve (20) and loading tool (30) upwards through that converging-shape crimping tool (48). The action crimps stent-mounted valve (20) and compresses prongs (34, 35) of loading tool (30) as these components pass into and through the narrow neck (52) of converging-shape crimping tool (48).

[0075] FIGS. 7A and 7B show alternative delivery packaging for the stent-mounted valve (20). In this variation, loading tool (30) and the converging-shape crimping tool (48) are provided separately from the stent-mounted valve (20). In this variation, the stent-mounted valve (20) is enclosed in closed packaging, storage container (50) having closure or lid (54). The storage container (54) is typically filled with a liquid, e.g., comprising a preservative such as glutaraldehyde. The exemplified stent-mounted valve (20) is shown having stent (22) with strut supports (24). A base (60) may be provided in the storage container (50) for supporting stent-mounted valve (20) in the liquid medium.

[0076] The various disclosed devices and combinations are also useful for other types of expandable stents, stent/valve combinations, and expandable prosthetics that are to be collapsed for delivery, delivered via a transcatheter procedure, and expanded at or before delivery.

[0077] In the variation shown in FIGS. 7A and 7B, to remove the stent-mounted valve (20) from the packaging, the user first removes cover (54) from storage container (50). The user then grasps loading tool (30) and slightly compresses prongs (34) inward and aligns the notches (36) of prongs (34) with the corresponding stent connectors (26) or regions of stent (22) such that when the prongs (34) are released in a controlled manner, stent (22) becomes connected to loading tool (30), as seen in FIG. 7B.

[0078] As noted above, prior to loading into the catheter delivery tube, the stent-mounted valve (20) may be washed to remove the preservative.

[0079] FIGS. 8-11 show the operation of the components, particularly the loading tool (30), stent-mounted valve (20), and converging-shape crimping tool (48), as they are taken from the integrated packaging (shown in FIG. 6) and placed in the catheter housing, and as the valve is implanted in the heart.

[0080] FIG. 8 is a schematic view illustrating the loading tool (30) and stent-mounted valve (20) after they have been removed from the packaging (50) of FIG. 6 and after the stent-mounted valve (20) and the loading tool (30) have been, respectively, crimped and collapsed inside of the converging-shape crimping tool (48). The crimping of stent-mounted valve (20) and the collapsing of the prongs (34) of loading tool (30) are accomplished by pulling upwardly on handle (56). Handle (56) draws those components up and through converging-shape crimping tool (48) causing the prongs (34) of loading tool (30) to switch from an open to a closed configuration while remaining connected to stent-mounted valve (20).

[0081] Handle (56) is removably attached to loading tool (30) perhaps via a quick-release type mechanical coupling (64). However, other suitable coupler designs may be employed for removably connecting handle (56) to loading tool (30). A two-position sliding clasp (65) or stopper is provided on the top of crimping tool (48). The sliding clasp (65) is shaped such that when in a first open position, handle (56) may be pulled upward. When the sliding clasp (65) is slid to a second (or closed) position, the sliding clasp (65) blocks upward movement of handle (56). Thus, following crimping of stent-mounted valve (20) by pulling it up into the neck (52) of crimping tool (48), the user slides sliding clasp (65) to the closed position and so prevents stent-mounted valve (20) and loading tool (30) from being prematurely released from crimping tool (48).

[0082] FIG. 8 also shows a circumferential indentation (57) in neck (52). This indentation (57) serves as a “safety stop,” in the sense that it prevents the stent-mounted valve (20) from retracting into the larger diameter section of the crimping tool (48) after it has been pulled into the narrow neck (52). Specifically, as loading tool (30) and stent-mounted valve (20) are drawn upward through crimping tool (48), short prongs (35) of loading tool (30) engage indentation (57). This serves to prevent the stent-mounted valve (20) from descending into the crimping tool (48), particularly after the handle (56) is removed, and to thereby prevent unwanted re-opening of stent-mounted valve (20). In sum, sliding clasp (65) prevents upward movement of loading tool (30) and valve (20); indentation (57) and short prongs (35) prevent downward movement of loading tool (30) and valve (20).

[0083] As is shown in FIG. 9, handle (56) is detached from loading tool (30) following crimping of stent-mounted valve (20) and loading tool (30) and subsequent closing of sliding clasp (65).

[0084] As illustrated in FIG. 10, loading tool (30) is then attached to a delivery catheter (66). comprising a catheter delivery tube (68) and an inner shaft (70) that extends coaxially through the interior of catheter delivery tube (68) to the loading tool (30). A mechanical coupling (64) connects the pusher or base connector (37) of loading tool (30) to inner shaft (70) of delivery catheter (66). Inner shaft (70) has the dual function of pulling the loading tool (30)/valve (20) into the catheter tube (68) and pushing the valve (20) out of the catheter tube (68) at implantation due to the relative motion between the inner shaft and the delivery tube. Said another way: backward movement of shaft (70) relative to the catheter delivery tube (68) causes loading tool (30) and stent-mounted valve (20) to be drawn out of crimping tool (48) and into catheter delivery tube (68). The loading tool (30) and stent-mounted valve (20) remain crimped or collapsed after entering the catheter delivery tube (68). The crimping tool (48) is then released and may be discarded. At this juncture, loading tool (30) and stent-mounted valve (20) are then retracted further into delivery catheter (66) by shaft (70). The assembly is then ready for passage through another catheter (or “outer tube”) to the implantation site in the heart.

[0085] In FIG. 11, engagement arms (25) are shown to be external to catheter tube (68) during the passage of the stent-mounted valve (20) to the delivery site. During implantation, the delivery catheter (66) is advanced over a guidewire until the distal tip of the stent-mounted valve (20) and the engagement arms (25) pass through the native aortic valve. The delivery catheter (66) is then slightly withdrawn to flare the engagement arms (25) laterally into the valve sinuses. At this point, the stent is still in a compressed state in the catheter delivery tube (68).

[0086] Subsequent retraction of the catheter delivery tube (68), while maintaining the stent-mounted valve (20) stationary using the inner shaft (70), causes release of stent-mounted valve (20) and its placement and opening within the native heart valve orifice. The releasing and opening of the stent-mounted valve (20) causes the stent (22) to expand away from and be automatically disconnected from the still-compressed loading tool (30), as seen in FIG. 12. As mentioned above, the prongs (34) of the loading tool (30) reside in the interior of the stent (22), and when the stent (22) opens, the stent connectors readily exit the notches (36) formed in the prongs (34) of the loading tool (30).

[0087] Having described the invention with regard to certain specific embodiments thereof, it is to be understood that the description is not meant as a limitation, since further modifications may now suggest themselves to those skilled in the art, and it is intended to cover such modifications as fall within the scope of the appended claims.