Patent Description:
The mitral valve lies between the left atrium and the left ventricle of the heart. Various diseases can affect the function of the mitral valve, including degenerative mitral valve disease and mitral valve prolapse. These diseases can cause mitral stenosis, in which the valve fails to open fully and thereby obstructs blood flow, and/or mitral insufficiency, in which the mitral valve is incompetent and blood flows passively in the wrong direction.

Many patients with heart disease, such as problems with the mitral valve, are intolerant of the trauma associated with open-heart surgery. Age or advanced illness may have impaired the patient's ability to recover from the injury of an open-heart procedure. Additionally, the high costs associated with open-heart surgery and extra-corporeal perfusion can make such procedures prohibitive.

Patients in need of cardiac valve repair or cardiac valve replacement can be served by minimally invasive surgical techniques. In many minimally invasive procedures, small devices are manipulated within the patient's body under visualization from a live imaging source like ultrasound, fluoroscopy, or endoscopy. Minimally invasive cardiac procedures are inherently less traumatic than open procedures and may be performed without extra-corporeal perfusion, which carries a significant risk of procedural complications.

During minimally invasive procedures for mitral valve replacement, the mitral valve prosthesis generally must be collapsed into a small delivery device for placement within the native mitral valve orifice. Such collapsing can be difficult and time-consuming. Safe and efficient delivery systems, loading devices, and methods for replacement of a cardiac valve that address some or all of these concerns are described herein.

<CIT> discloses a holder for a heart valve prosthesis, the holder including a hub portion having a longitudinal axis, an engagement portion coupled to the hub portion and including plural finger members variably positionable relative to the hub portion between a collapsed condition wherein the finger members are closed onto the hub portion and an expanded condition wherein the finger members radially protrude with respect to the hub portion to engage a heart valve prosthesis.

There is hereinafter disclosed a loading device configured to radially collapse an expandable medical implant. The disclosed device includes an operating handle having an opening therein extending along a longitudinal axis thereof, a native sheath having a proximal end coupled to a distal end of the operating handle and partially extending into the opening of the operating handle, such that the native sheath is configured to translate relative to the operating handle parallel to the longitudinal axis, a removable sheath having a proximal end removably coupled to a distal end of the native sheath, an actuation rod extending parallel to the longitudinal axis at least partially through the opening of the operating handle, a lumen of the native sheath, and a lumen of the removable sheath, a distal end of the actuation rod being configured to be removably coupled to the expandable medical implant, and a first control element movable relative to the operating handle and coupled to the native sheath, the first control element being configured to translate the native sheath and the removable sheath relative to the operating handle in first and second longitudinal directions parallel to the longitudinal axis.

Said hereinafter disclosed loading device may also include a threaded rod extending within the opening parallel to the longitudinal axis and affixed to the native sheath. The first control element may be a sheathing knob threadedly engaged with the threaded rod, such that rotational motion of the sheathing knob causes the threaded rod, the native sheath, and the removable sheath to translate in one of the first or second longitudinal directions. The loading device may also include a second control element movable relative to the operating handle and coupled to the actuation rod. The second control element may be configured to translate the actuation rod relative to the operating handle in the first and second longitudinal directions. The loading device may also include a threaded rod extending within the opening parallel to the longitudinal axis and affixed to the actuation rod. The second control element may be a retention mechanism knob threadedly engaged with the threaded rod, such that rotational motion of the retention mechanism knob causes the actuation rod to translate in one of the first or second longitudinal directions.

Said hereinafter disclosed loading device may also include a ratchet and pawl mechanism that is coupled to the retention mechanism knob. The ratchet and pawl mechanism may be configured to permit rotation of the retention mechanism knob only in a single rotational direction. The loading device may also include a coupling element extending around the proximal end of the removable sheath and the distal end of the native sheath. The coupling element may removably couple the removable sheath to the native sheath. The lumen of the removable sheath may define a funnel having a first diameter at a distal end of the removable sheath and a second diameter at the proximal end of the removable sheath, the first diameter being greater than the second diameter.

The removable sheath may have a flange at the distal end of the removable sheath, the flange having a distal-facing surface extending in a plane oriented substantially perpendicular to the longitudinal axis, the flange having a through-opening that defines the first diameter at the distal end of the removable sheath. The actuation rod may have a threaded feature at the distal end thereof that is configured to be mated with a corresponding threaded feature of a retention mechanism that is coupled to the expandable medical implant. A medical combination may include the loading device described above, the expandable medical implant, and a retention mechanism removably coupling the expandable medical implant to the actuation rod of the loading device. The expandable medial implant may be radially collapsed within the lumen of the removable sheath.

There is also hereinafter disclosed a method of loading an expandable medical implant into a distal end of a delivery device. The disclosed method includes inserting an outer sheath at the distal end of the delivery device into a lumen of a brace of a loading device, removably coupling a retention mechanism to an inner shaft extending along a longitudinal axis within the outer sheath of the delivery device, the retention mechanism coupling the expandable medical implant to the inner shaft, applying a force onto the retention mechanism, the applying including pressing a distal end of a packing rod of the loading device onto a distal end of the retention mechanism, the pressing including actuating a control element of the loading device to translate the packing rod relative to the loading device in a longitudinal direction parallel to the longitudinal axis, and inserting the expandable medical implant into the outer sheath of the delivery device while the distal end of the packing rod and the outer sheath of the delivery device are positioned within the lumen of the brace of the loading device, the inserting of the expandable medical implant including further translating the packing rod relative to the loading device and the outer sheath of the delivery device in the longitudinal direction.

In said hereinafter disclosed method the control element may be an actuation knob threadedly engaged with a threaded rod that is affixed to the packing rod, and the applying of the force onto the retention mechanism may include rotating the actuation knob. The lumen of the brace may define a funnel having a first diameter at a proximal end of the brace and a second diameter at a distal end of the brace, the first diameter being greater than the second diameter. The inserting of the expandable medical implant into the outer sheath may include collapsing the expandable medical implant in a plurality of radial directions perpendicular to the longitudinal axis while at least a portion of the expandable medical implant is positioned within the lumen of the brace. The method may also include removing the outer sheath of the delivery device from the lumen of the brace of the loading device, the expandable medical implant being disposed within the outer sheath in a collapsed state after the removing is completed.

The loading devices described herein can be used to load a wide variety of replacement heart valves (also referred to herein as "replacement valves" or "valve"), such as prosthetic valves, into one or more delivery systems. Exemplary prosthetic valves that can be delivered and deployed with the delivery devices described herein include the expandable prosthetic valves described in App. No. <CIT>, in <CIT>, and in International Patent Application filed May <NUM>, <NUM>, titled "REPLACEMENT MITRAL VALVES," and in <CIT>, titled "REPLACEMENT CARDIAC VALVES AND METHODS OF USE AND MANUFACTURE,". For example, the loading devices herein are configured to deliver and deploy a replacement heart valve, such as a mitral valve, that includes distal and proximal anchors.

The loading devices and methods described herein can be used to load replacement valves into a delivery system, which can then be used to deliver the replacement valves into patients. In some embodiments, the loading devices can be used to load replacement valves into a trans-septal delivery system, which may be used to compensate for a force required to load a long, flexible catheter such as that used for a trans-septal delivery system. In some cases, the loading devices can be used to compensate for the force required to load a replacement valve, which may be difficult to achieve with a long, flexible catheter such as that used for a trans-septal delivery system. For example, it may be difficult for a long flexible device to apply the necessary forces since flexibility of a device may compromise other characteristics, like tensile strength. The loading devices may be suitable for use with any type of replacement heart valve, including replacement mitral valves.

<FIG> shows a perspective view of a replacement mitral valve <NUM>, in accordance with some embodiments. The valve <NUM> can include an inner strut frame <NUM> and an outer anchor assembly <NUM>, which can cooperate to form a rigid support structure having an atrial side <NUM> and a ventricular side <NUM>. In some embodiments, a skirt <NUM> covers outer surfaces of the support structure, and one or more leaflets <NUM> are positioned within a central channel of the support structure. Petals <NUM> of the outer anchor assembly <NUM> can be configured to collapse to reduce an outer diameter of the support structure when the support structure is loaded into the loading device and/or delivery system. When the valve <NUM> is in an expanded state, the petals <NUM> of both the atrial side <NUM> and a ventricular side <NUM> are fully extended radially outward, as shown in <FIG>. The valve <NUM> is naturally in an expanded state when no force is applied to the petals <NUM>. When the valve <NUM> is in a collapsed state, the petals <NUM> of both the atrial side <NUM> and a ventricular side <NUM> are at least partially collapsed radially inward. The valve <NUM> can be placed in a collapsed state by applying pressure onto the petals <NUM> in a radially inward direction. In a collapsed state, the valve <NUM> has a higher degree of potential energy (e.g., is spring loaded) compared to when the expanded state.

According to some embodiments, the loading device as described herein is configured to load a valve (e.g., valve <NUM>) into an intermediate device that maintains the valve in a collapsed state prior to being transferred into the delivery system. These embodiments are described herein with reference to <FIG> and <FIG>. According to some embodiments, the loading device is configured to load the valve directly (e.g., in an expanded state) into the delivery system. These embodiments are described herein with reference to <FIG> and <FIG>.

<FIG> show an exemplary loading device <NUM>, which includes various features for placing a valve in a collapsed (high energy) state. <FIG> shows a perspective view, <FIG> shows a longitudinal section view, <FIG> shows a close up longitudinal section view, and <FIG> shows an alternative perspective view of the loading device <NUM>.

Referring to <FIG> and <FIG>, the loading device <NUM> can include a handle <NUM> suitable for a user's hand, and an elongate body <NUM> with a central channel that is configured to secure the valve (not shown) therein for placement within a delivery system (not shown). The elongate body <NUM> can include one or more sheaths, including a native sheath <NUM>, a removable sheath <NUM> (also referred to as a tube or funnel) and a shim sheath <NUM>. The native sheath <NUM> may be securely attached to the handle <NUM>. For example, the native sheath <NUM> can be positioned at least partially within the handle <NUM> and be configured to move relative to the handle <NUM>. In some cases, the native sheath <NUM> is attached to a sheath adapter using, for example, a leadscrew. The removable sheath <NUM> may be removable from the handle <NUM>, and be adapted to hold the valve therein. The shim sheath <NUM> can be used to allow compatibility with different diameters of sheaths and can slide over the native sheath <NUM> and/or the removable sheath <NUM>. The loading device <NUM> can be adapted to secure the valve in a collapsed state.

The distal end of the removable sheath <NUM> can have a flange <NUM> that can be configured to provide smooth entry of the valve with minimal valve contact. The central channel of the elongate body <NUM> can include an actuation tube <NUM> (or rod) that engages with a retention mechanism that is coupled to the valve. In some embodiments, the actuation tube <NUM> includes a threaded inner or outer surface to provide secure engagement with the retention mechanism.

The tip <NUM> of the elongate body <NUM> can have features therein (e.g., on the inner diameter thereof) to guide the valve retention mechanism. For example, the tip <NUM> may have a funnel shape for guiding the valve retention mechanism and/or align the actuation tube <NUM> therein. The handle <NUM> can include a sheathing knob <NUM> (or first control element) to control actuation of the removable sheath <NUM>. In some embodiments, rotation of the sheathing knob <NUM> can cause a translation motion of a sheath adaptor <NUM> and the actuation tube <NUM> in a longitudinal direction. In some embodiments, a torque bar <NUM> can be used for added mechanical advantage when turning the sheathing knob <NUM>. In some embodiments, the torque bar <NUM> is removable. The handle <NUM> can include a retention mechanism knob <NUM> (or second control element) for controlling the retention mechanism. For example, the retention mechanism knob <NUM> may allow a user to switch between a first mode where the retention mechanism extended, and a second mode wherein the retention mechanism is retracted. In some cases, this may provide finer control of the retention mechanism. For example, this may allow for partial unsheathing of a valve if, for instance, it is determined that the valve is not collapsing correctly (e.g., unsymmetrically). The handle <NUM> may include proximal and distal race plates <NUM> and <NUM>, which may be configured to ensure unidirectional travel (e.g., via a ratchet mechanism) and/or be configured to provide audible feedback to a user (e.g., via a pawl mechanism). A proximal terminator <NUM> and a proximal stop <NUM> may be configured to control limits of translation of the actuation tube <NUM>.

The close up view of <FIG> shows a variation of the device <NUM> that includes flanges <NUM> on the elongate body <NUM>. The flange(s) <NUM> may have one or more bosses that are adapted to allow partnered translation <NUM> of the removable sheath <NUM> with respect to the native sheath <NUM>. This can allow for both loading and unloading forces to be applied to the removable sheath <NUM> without losing tension on the retention mechanism during loading of the valve. In some embodiments, a center screw <NUM> can be adapted to limit (e.g., prevent) rotation of the removable sheath <NUM> relative to the native sheath <NUM>. <FIG> shows an optional sheath adapter <NUM>, which can be used to allow for different sized sheaths as an alternative to using the shim sheath <NUM> (<FIG>).

<FIG> and <FIG> show perspective and longitudinal section views, respectively, of a loading device <NUM>. The loading device <NUM> has many similar features as the loading device <NUM> (<FIG>). For example, the loading device <NUM> can include a handle <NUM> and an elongate body <NUM> having a central channel. The elongated body can include a native sheath <NUM> and a removable sheath <NUM>. The removable sheath <NUM> can have a flange <NUM> that can be configured to provide smooth entry of the valve with minimal valve contact. An actuation tube <NUM> (or rod) can be configured to engage with a retention mechanism coupled with the valve. A sheathing knob <NUM> can be configured to control actuation of the removable sheath <NUM>. In some embodiments, rotation of the sheathing knob <NUM> can cause a translation motion of a sheath adaptor <NUM> in a longitudinal direction. In some embodiments, the handle <NUM> includes an indicator, which can be operationally coupled with the sheathing knob <NUM> to indicate to a user whether the loading device <NUM> is ready for loading a valve assembly.

The loading device <NUM> may be configured to perform the entire collapse and covering of the valve. According to some embodiments, the loading device <NUM> does not include a separate retention mechanism knob (e.g., retention mechanism knob <NUM> of <FIG>). In some situations, this may provide more ease and convenience for loading the valve. This may also provide a more simple assembly process for manufacturing the loading device (e.g., reduction in parts).

The removable sheaths (also referred to as funnels) described herein can be adapted to cooperate with delivery systems having elongated bodies (e.g., outer sheaths) of different diameters. The removable sheaths may be adjustable to match different catheter sizes without changing the loading tool (e.g., versus emphasis on matching various loading tools). This way, the removable sheath can be modified to fit any of a number of different delivery systems while maintaining compatibility with a single loading tool configuration. <FIG> show longitudinal section views of exemplary removable sheaths having different interface features. In <FIG>, the removable sheath <NUM> has an inner diameter portion <NUM> that has a smaller or equal outer diameter compared to the inner diameter of the corresponding native sheath <NUM>. The inner diameter portion <NUM> of the removable sheath <NUM> may also be adapted to interface with a corresponding portion of the delivery system (e.g., an outer sheath). In <FIG>, the removable sheath <NUM> has an inner diameter portion <NUM> that has a larger outer diameter compared to the inner diameter of the corresponding native sheath <NUM>. The inner diameter portion <NUM> of the removable sheath <NUM> may also be adapted to interface with a corresponding portion of the delivery system (e.g., an outer sheath).

A valve can be loaded onto a loading device (e.g., loading devices <NUM> or <NUM>) in a number of stages. <FIG> shows an example of multiple phases of loading a valve holder assembly <NUM> into a loading device, according to some embodiments. One or more of the operations shown in <FIG> can be performed while the valve and/or loading device (or a portion thereof) is/are submerged in a solution (e.g., saline solution).

Referring to <FIG>, to prepare the valve for loading, the ventricular side of the valve <NUM> can be coupled to a valve holder <NUM>, and the atrial side of the valve can be coupled to a retention mechanism <NUM> (also referred to as a suture ring and/or a florette), which may include or be coupled to a first hypotube <NUM>. On the ventricle side, the valve holder can include a second (e.g., larger) hypotube <NUM> that can be used to control (e.g., prevent) rotation of the valve <NUM> during loading. The first hypotube <NUM> and/or the second hypotube <NUM> may be centrally located with respect to the valve holder assembly <NUM> and may be made of a corrosion resistant material, such as stainless steel. The second hypotube <NUM> can be coupled to a stand <NUM>, which a user can hold in place or twist during loading. The valve support <NUM> can be used to assure proper positioning of the valve <NUM>. The second hypotube <NUM> can be configured to set the distance of a valve support <NUM> (also referred to as a spacer) relative to the valve holder <NUM>, so that the valve <NUM> can collapse at a correct height relative to the valve support <NUM>. The second hypotube <NUM> may be affixed to the valve support <NUM>. For example, the second hypotube <NUM> can dictate the distance of the valve support <NUM> from the face <NUM> of the valve holder <NUM>, to control how and/or where the valve <NUM> is supported.

One or more retainers <NUM> (e.g., <NUM>, <NUM>, <NUM> or more retainers), which can correspond to wires, can be used to couple the petals of the ventricular side of the valve <NUM> to the valve holder <NUM>. In some embodiments, the retainers <NUM> are have hooks that attach to the petals of the ventricular side. In some cases, hooks of the retainers <NUM> poke through the skirt of the valve. The retainers <NUM> (and in some cases other metal portions of the valve holder assembly) are made of a corrosion resistant material (e.g., nickel titanium). In some cases, the retainers <NUM> are made of material that is non-reactive with the inner strut frame of the valve <NUM>, since retainers <NUM> may directly contact the inner strut frame of the valve <NUM> during the valve collapsing process. On the atrial side, the retention mechanism <NUM> may be part of or be coupled to the hypotube <NUM>. In some embodiments, the retention mechanism <NUM> corresponds to or includes a ring having a central opening that communicates with a central opening of the hypotube <NUM>. The retention mechanism <NUM> can include one or more sutures <NUM> (also referred to as threads) that is/are threaded therethrough. The sutures <NUM> can be tethered to (e.g., looped through) a corresponding petal of the atrial side and interact with features therein. For example, the sutures <NUM> may loop around pins on the petals. In some embodiments, the sutures <NUM> are threaded through the skirt of the valve. In some embodiments, the sutures <NUM> are one continuous thread. Tension may be placed on the sutures <NUM> to provide control during the loading process. In some cases, the ends of the sutures <NUM> are pinched (e.g., crimped) to prevent possible hooking onto other features of the valve holder assembly. In some cases, the crimps or coils on sutures <NUM> are secured in place by an adhesive, which can help maintain tension and avoid inadvertent separation of the sutures <NUM>.

Once the valve <NUM> is attached to the valve holder, this assembly can be coupled to the loading device. <FIG> shows a valve holder assembly <NUM> being loaded onto a loading device <NUM>, in accordance with some embodiments. The tip of the retention mechanism <NUM> can be coupled to an actuation tube <NUM> positioned within a channel of the removable sheath <NUM> of the loading device <NUM>. In some embodiments, the retention mechanism <NUM> is screwed onto the actuation tube <NUM> by twisting the stand <NUM> (<FIG>). After securing the valve holder assembly <NUM> and the loading device <NUM>, a sheathing knob of the loading device can be rotated to pull the actuation tube <NUM> and the retention mechanism <NUM> proximally toward the loading device <NUM>. Since the valve holder assembly <NUM> and loading device <NUM> are held in place, a resulting tension placed on the petals of the atrial side of the valve the causes the petals to partially collapse radially inward.

As shown in <FIG>, the sheathing knob of the loading device can continued to be rotated until the atrial petals collapse radially inward to an extent sufficient for the atrial side of the valve <NUM> to enter the channel of the removable sheath <NUM>. The retainers <NUM> can then be removed from ventricular side of the valve <NUM>. The sheathing knob of the loading device can continued to be rotated until the valve <NUM> is fully enclosed within the removable sheath <NUM>. The removable sheath <NUM>, with the collapsed valve inside, can then be removed from the loading device for loading into the delivery system (i.e., from the removable sheath), as show in <FIG>. The hypo-tubes <NUM> and <NUM> and valve support <NUM> can also be configured to be withdrawn and removed. In some cases, the sutures <NUM> remain coupled to the valve during installation into the delivery system. Apparatuses and method for loading a valve into a delivery system may be described in International Patent Application No. <CIT> and <CIT>.

<FIG> shows a perspective view of a valve holder assembly <NUM> that can be loaded into a loading device <NUM> having sheathing knob and a retention mechanism knob. <FIG> shows a perspective view of a valve holder assembly <NUM> that can be loaded into a loading device <NUM> having sheathing knob (i.e., without a retention mechanism knob).

In some embodiments, the valve can be loaded into the delivery system from an elongated tube, referred to as a chaser tube. An exemplary loading device in the form of a chaser tube <NUM> is shown in <FIG>. The valve <NUM> can be loaded into the chaser tube <NUM>. In some cases, a loading tool is used to position the valve <NUM> into chaser tube <NUM>. The atrial side of the valve <NUM>, including the retaining mechanism <NUM> (e.g., florette), can be installed into the chaser tube <NUM> first. This can be accomplished by pulling the retaining mechanism (e.g., manually or automatically) until the petals of the valve collapse and the valve takes on a smaller diameter, as described herein. As shown in 7B, the chaser tube <NUM> can have a diameter that is smaller than the inner diameter of an outer sheath <NUM> as part of a delivery system <NUM> (i.e., used to deliver the valve into a patient). In some embodiments, the outer sheath <NUM> corresponds to catheter (or a portion thereof). The chaser tube <NUM> can be positioned partially within the outer sheath <NUM> to align the chaser tube <NUM> and outer sheath <NUM>. In some cases, the outer sheath <NUM> is pushed over the chaser tube <NUM>. The retaining mechanism <NUM> can be coupled to a distal assembly <NUM> within the outer sheath <NUM> to maintain tension on the valve <NUM>. When the chaser tube <NUM> is pulled (e.g., manually or automatically), the valve <NUM> exits the chaser tube <NUM> and is retained within the outer sheath <NUM>. In some cases, the valve <NUM> expands a little during this process. The chaser tube <NUM> can then be removed, leaving the valve <NUM> within the outer sheath <NUM>.

An exemplary use of a chaser tube <NUM> with a split sheath delivery system <NUM> is shown in <FIG>. A split sheath delivery system <NUM> can include a proximal sheath <NUM> and a distal sheath <NUM>. As shown, the valve <NUM> can be loaded into the chaser tube <NUM>, which can be placed inside the proximal sheath <NUM>. The retaining mechanism <NUM> (e.g., florette) can then be attached to the distal assembly <NUM>, and the distal sheath <NUM> can be pulled over the distal portion of the chaser tube <NUM>. In some embodiments, a threaded nose-cone tool is used to terminate the distal sheath <NUM> after transfer. Once the valve <NUM> is within the sheath <NUM>, the chaser tube <NUM> can be removed.

Another embodiment of a chaser tube <NUM> is shown in <FIG>. The chaser tube <NUM> can have a diameter that is substantially the same as the diameter of the sheath <NUM> (or the distal sheath <NUM> if a split sheath is used) and a proximal lip having a wider diameter so that it is configured to fit over the outer sheath <NUM> (and/or the proximal sheath <NUM> if a split sheath is used). The valve <NUM> can be loaded into the chaser tube <NUM>. In some cases, a loading tool is used to position the valve <NUM> into chaser tube <NUM>. The chaser tube <NUM> can then be aligned over the outer sheath of the delivery system. A pull system <NUM> can then be attached to the retaining mechanism (e.g., florette or first hypotube) of the valve assembly and pulled proximally to pull the valve <NUM> into the sheath <NUM> (or <NUM>/<NUM> if a split sheath) that is coupled to the catheter <NUM> as part of the delivery system. In some instances, the catheter <NUM> includes a layer of material therein to facilitate loading of the valve <NUM> within the delivery system.

<FIG> show various views of another exemplary loading device <NUM>, which can be configured to directly load a valve into a delivery system. The loading device <NUM> may advantageously avoid the transfer steps of loading the valve in an intermediate device (e.g., removable sheath and/or chaser tube). In some cases, this can minimize corrosion of the valve. The loading device <NUM> may include various valve tethering mechanisms, and may provide an internal support to collapse the valve in a symmetric, repeatable manner.

<FIG> and <FIG> show a perspective view and longitudinal section view, respectively, of loading device <NUM>. The device <NUM> can include a handle <NUM> and a brace <NUM>, which can be configured to interface with a valve delivery system. For example, the brace <NUM> can be configured to fit around a delivery catheter <NUM> (e.g., that is part of the delivery system). A plurality (e.g., three) brace arms <NUM>, which extend from the brace <NUM> to the handle <NUM>, they extend radially outward and transfer axial force from loading back to the handle <NUM>. This arrangement may prevent the force of loading from pushing the catheter <NUM> and loading device <NUM> apart. The plurality of brace arms <NUM> can be spaced from one another so as to keep the valve from prevent loading on the valve while providing room to access the valve during its collapse. Thus, for example, in some embodiments, the brace arms <NUM> can be positioned at about <NUM> degrees, <NUM> degrees, and <NUM> degrees apart, respectively. The device <NUM> can include a flange <NUM> radially inward of the brace arms <NUM> and at a proximal end of the brace <NUM>. The flange <NUM> can have an internal radius that guides the valve into the delivery catheter <NUM>. A packing rod <NUM> can extend from the handle <NUM> toward the brace <NUM>. The packing rod <NUM> can include a proximal portion <NUM> (proximal to the handle <NUM>) and a distal portion <NUM>. In some embodiments, the proximal portion <NUM> has a larger outer diameter than that of the distal portion <NUM> (e.g., tapers down). This configuration may reduce the occurrence of asymmetric valve collapse during loading. In some embodiments, the packing rod <NUM> (or a portion thereof) can be replaced with a balloon.

In some embodiments, fasteners 1018a and 1018b (e.g., screws) can be used to secure and/or remove one of the bracing arms <NUM> (e.g., arm <NUM> that is about <NUM> degrees away from the other two arms). The one or more bracing arm <NUM> may be removed in order to provide space for catheter insertion into the brace <NUM> and can then be replaced by attachment with the fasteners 1018a and 1018b. The handle <NUM> can include a knob <NUM>, and optionally a torque bar <NUM>, for controlling the loading process. The knob <NUM> can be configured to turn a threaded rod <NUM>, which advances the packing rod <NUM> to pack the valve into the delivery catheter <NUM>. Reversing the direction of the knob <NUM> can retract the packing rod <NUM> from the delivery catheter <NUM>.

In some embodiments, the delivery device <NUM> can include a through-lumen extending through the handle <NUM> and packing rod <NUM>. The through-lumen can be used, for example: (<NUM>) as a port to input saline for an internal support balloon (if replacing the packing rod <NUM>); (<NUM>) to allow a guidewire, mandrel, or other lumen to remain through the device <NUM> prior to, during, or after loading of the valve without interrupting; and/or (<NUM>) to be used with a stabilizer or stand that would allow the valve to be attached to the loading device <NUM> directly.

<FIG> show section views of the loading device <NUM> being used to load a valve into a delivery system <NUM>, according to some embodiments. <FIG> shows loading device <NUM> during a pre-packing process. The valve retention mechanism <NUM> of a valve <NUM> can be coupled to an inner catheter <NUM>. Close up view <NUM> shows a threaded connection between the retention mechanism <NUM> and the inner catheter <NUM>, according to some embodiments. The retention mechanism <NUM> can include or be coupled to one or more sutures <NUM> (e.g., sutures, tabs, tethers, loops). In some embodiments, the walls of the delivery catheter <NUM> includes one or more internal layers to accommodate valves of different sizes and shapes, as needed. In some cases, the delivery catheter <NUM> includes one or more outer layers <NUM> (also referred to as outer sheaths). The brace <NUM> of the loading device <NUM> can have an opening that fits over an outer diameter of the delivery catheter <NUM>. In some cases, an opening of the brace <NUM> has a larger diameter portion <NUM> that accommodates a shoulder portion of the delivery catheter <NUM>.

When the knob <NUM> of the loading tool <NUM> is turned, the packing rod <NUM> can place a pushing force upon the inner catheter <NUM> at a load transfer area <NUM>, thereby causing the valve <NUM> to be pulled into and collapse within the delivery catheter <NUM>. The inner catheter <NUM> can facilitate guiding of the valve <NUM> such that the valve is centered within the delivery catheter <NUM>. The inner catheter <NUM> may prevent (or reduce the occurrence of) the valve <NUM> from twisting during the loading. The packing rod <NUM> can be tapered such that the distal portion <NUM> applies a concentrated pushing force in a central region of the load transfer area <NUM> to facilitate symmetric collapse of the valve <NUM>. The larger diameter proximal portion <NUM> can maintain a central position of the valve <NUM> as the proximal portion <NUM> enters the delivery catheter <NUM>, thereby facilitating symmetric collapse of the valve <NUM>.

<FIG> shows the valve <NUM> in a further progressively packed state within the delivery catheter <NUM>. Bracing arms <NUM> can secure the position of the loading device <NUM> with respect to the delivery catheter <NUM>, thereby providing a negative resistance <NUM> to the forward force <NUM> of the advancing packing rod <NUM> during the loading operation. If readjustments of the position of the valve <NUM> are needed, the packing rod <NUM> can be retracted and re-advanced into the delivery catheter <NUM> until the valve <NUM> is sufficiently packed. Once the valve <NUM> is determined to be adequately packed, the packing rod <NUM> can be decoupled from the valve retention mechanism <NUM>.

<FIG> shows a post-packing operation, whereby the threaded rod <NUM> is turned (e.g., by the knob <NUM>) to move the packing rod <NUM> a reverse <NUM> direction, thereby retracting the packing rod <NUM> from within the delivery catheter <NUM> and leaving the collapsed valve <NUM>, with the valve retention mechanism <NUM>, in the delivery catheter <NUM>. Once the packing rod <NUM> is sufficiently retracted, the loading device can be decoupled from the delivery catheter <NUM> by unfastening the fasteners <NUM> (e.g., screws) to remove one or more of the bracing arms <NUM> and brace <NUM>. In some embodiments, the removal involves sliding the delivery catheter <NUM> radially out of the brace <NUM>. The delivery system <NUM> is then loaded with valve <NUM> for delivery into the patient.

In some embodiments, a balloon can be situated in a region <NUM> internal to the bracing arms <NUM> to provide further support for the packing rod <NUM> during forward and/or reverse movement of the packing rod <NUM>. For example, the balloon can be inflated during forward movement <NUM> (<FIG>) of the packing rod <NUM> to provide lateral support for the packing rod <NUM>. The balloon can then be deflated prior to or during movement of the packing rod <NUM> in the reverse <NUM> direction in order to reduce forces on and/or interaction with the valve <NUM> (e.g., valve leaflets).

According to some embodiments, the direct loading device has two bracing arms. <FIG> show a perspective view and section view, respectively, of a loading device <NUM> having two bracing arms <NUM>. A two-arm configuration may provide different features than a three-arm configuration. For example, a two-arm configuration may provide better access to the valve positioned therein compared to a three-arm configuration. The two-arm configuration may be easier to maneuver during a loading operation (e.g., be less bulky). The two-arm configuration may be easier to manufacture and require less manufacturing material compared to a three-arm configuration. The three-arm configuration may provide better stability of the valve during the loading process compared to two-arm configuration.

<FIG> show a three-arm loading device <NUM> and a two-arm loading device <NUM>, respectively, at various stages of loading valves into delivery catheters. In some cases, the three-arm loading device <NUM> is configured to stably sit on a surface (e.g., table) during the loading process. In some cases, the two-arm loading device <NUM> is configured to be supported by a user during the loading process.

The sizes and shapes of various components of the loading devices described herein can be configured to accommodate requirements of particular applications. For example, in some applications it may be beneficial to have a shorter or longer loading device. <FIG> show exemplary loading devices <NUM> and <NUM> have different lengths. A shorter loading device <NUM> can reduce that distance that the valve travels during loading, thereby reducing the chances of corrosion of parts of the valve. In some cases, a shorter removable sheath <NUM> is used to contain the valve (e.g., compared to a longer removable sheath <NUM>).

Any of the loading devices described herein can be configured to be exposed to an autoclaving process. For example, the material (e.g., polymer, silicone, metal and/or ceramic) of various parts of the loading device may be durable enough to withstand the high temperature and conditions of autoclaving. If polymer materials are used, the polymer components can be configured to withstand repeated heat cycling during autoclaving. In some embodiments, the polymer components are replaced with non-polymer components (e.g., metal and/or ceramic). In some cases, portions of the loading device may be configured to shrink to minimize possible corrosion of the valve enclosed therein (e.g., when exposed to a solution).

Any of the loading device described can be implemented with a leave-in mandrel. A leave-in mandrel refers to a mandrel that remains within the delivery system with the collapsed valve. Once the delivery system delivers the valve (without the leave-in mandrel) into the patient, the leave-in mandrel can remain within the delivery device. <FIG> show section views of an exemplary delivery system <NUM> having a leave-in mandrel <NUM>. At <FIG>, the valve <NUM> is loaded within the delivery catheter <NUM> such that the collapsed valve <NUM> is supported by the leave-in mandrel <NUM>. In preparation for delivering into the patient, a suture catheter <NUM> can be coupled to a suture ring <NUM>, which is in turn coupled to sutures <NUM>. At 15B, the delivery catheter <NUM> is pulled back in a backward direction <NUM>, and the suture catheter <NUM> is extended in a forward direction <NUM>. This causes the petals of the valve <NUM> to expand. After the valve <NUM> has been deployed from the delivery catheter <NUM>, at <FIG>, the suture catheter <NUM> can be extended further in the forward direction <NUM> to pull the sutures <NUM> off of the valve petal features to constrain the sutures <NUM> tucked back and contained within the inner diameter of the delivery catheter <NUM>, as shown in close up view <NUM>. This increased constraint may ease the final release of the valve <NUM>, and/or may increase the ability to pull the sutures <NUM> off in one motion regardless of coaxiality and/or centrality of delivery system relative to the valve <NUM>. The leave-in mandrel can keep the sutures <NUM> constrained and avoid the sutures <NUM> from catching during the valve delivery process. In some embodiments, the leave-in mandrel has a tapered end and open central region, which can minimize compression and prevent blocking of the sutures <NUM>.

In some embodiments, a chaser tube can be used to directly load a valve into a split sheath delivery system. <FIG> shows a section view of a portion of an exemplary split sheath delivery system <NUM> having a distal assembly <NUM>, a proximal sheath <NUM> and a distal sheath <NUM>. <FIG> show how a chaser tube <NUM> can be used the split sheath delivery system <NUM>. At <FIG>, the valve <NUM> can first be loaded into the proximal sheath <NUM> (e.g., via attachment of the proximal loops to the distal assembly <NUM>) such that at least the proximal anchor is collapsed therein. The chaser tube <NUM> is positioned around the distal assembly <NUM> in a proximal direction. At <FIG>, the chaser tube <NUM> is pulled distally over the proximal sheath <NUM> to collapse the distal anchor and load the valve <NUM> therein. In this embodiment, the diameter of the chaser tube <NUM> is greater than the diameter of a proximal sheath <NUM> (and can be, for example, substantially equal to the diameter of a distal sheath <NUM>). In some embodiments, a loading cone <NUM> is optionally used to guide the collapsing of the ventricular petals of the valve <NUM>. Once loaded inside the chaser tube <NUM>, at <FIG>, the distal sheath <NUM> can be pulled proximally thereover as the chaser tube <NUM> is pulled proximally. The chaser tube <NUM> can then be removed (e.g., cut, unclamped, or otherwise removed). The chaser tube <NUM> can advantageously be used with embodiments of a split sheath delivery system where a retaining mechanism is not detachable from the rest of a distal assembly of the delivery device. Examples of split sheath delivery systems are described in International Patent Application No. <CIT> and <CIT>.

Although described as being used for the trans-septal delivery method, the delivery devices described herein can also be used for a trans-atrial or surgical delivery methods.

Aspects of the delivery devices and methods may be combined with aspects of the delivery devices and methods described in <CIT>, <CIT>, or International Patent Application filed May <NUM>, <NUM> and titled "REPLACEMENT MITRAL VALVES.

Although described herein for use with a mitral valve prosthetic, the delivery systems described herein can be used with a variety of different implantable devices, including stents or other valve prosthetics.

Claim 1:
A loading device (<NUM>, <NUM>, <NUM>, <NUM>) configured to radially collapse an expandable medical implant, the loading device comprising:
an operating handle (<NUM>) having an opening therein extending along a longitudinal axis thereof;
a brace (<NUM>) coupled to the operating handle and configured to interface with a distal end of a delivery system configured to deploy the expandable medical implant, the brace having a lumen extending therethrough in a direction parallel to the longitudinal axis;
a plurality of brace arms (<NUM>, <NUM>) that extend from the brace to the operating handle, the brace arms being configured to transfer a force acting on the brace along the longitudinal axis directly to the operating handle;
a packing rod (<NUM>) extending between the operating handle and the brace in first and second longitudinal directions parallel to the longitudinal axis; and
a control element (<NUM>) movable relative to the operating handle, movable relative to the packing rod and coupled to the packing rod, the control element being configured to translate the packing rod relative to the operating handle and the brace in the first and second longitudinal directions.