Patent Description:
The invention relates to a modular valve replacement system implantable into a heart as defined by claim <NUM>.

Mitral valve regurgitation is one of the most prevalent forms of valve disease. Mitral valve regurgitation is especially impactful in an aging population in the developing world where it affects approximately <NUM>% of those older than <NUM> years of age. Mitral valve regurgitation is a health issue because mitral valve incompetence causes an increased volume of blood to be pumped back or retained in the left atrium and pulmonary circulation, which places increased strain on the left ventricle. This can cause irreversible left ventricular damage and even decompensation. Mitral valve replacement or repair can be an efficacious treatment for some patients with mitral valve regurgitation, yet up to half of the patient population is not referred for mitral valve replacement or repair surgery due to a perceived risk of such procedures.

Mitral valve regurgitation is typically due to a reduction of functional competence of the mitral valve, which relies on a variety of anatomical structures and coordinated interaction of the left ventricle, papillary muscles, chordae tendineae, anterior leaflet, posterior leaflet, and the mitral valve annulus. Damage to any one of those structures can impact valve function or competence. Mitral valve regurgitation is categorized as degenerative or functional (or primary or secondary, respectively). Functional mitral valve regurgitation is typically defined as regurgitation in the setting of normal valve leaflets, which is associated with incomplete mitral valve leaflet coaptation (drawing together and/or overlap of the leaflets) often due to dilation of the annular area or left ventricular dysfunction. The depth and length of coaptation is associated with mitral valve function. Examples include ischemic mitral valve regurgitation and dilated cardiomyopathy. Degenerative mitral valve regurgitation examples include leaflet perforations, prolapse, rheumatic valve disease, or mitral annular calcification. Therefore, there is a significant need to develop efficacious devices and procedures to treat mitral valve regurgitation. <CIT> discloses a prosthetic valve assembly for replacing a native heart valve that comprises a radially expandable and compressible support structure, the support structure comprising an annular frame and comprising an annular sealing member extending radially inwardly into the lumen of the frame and having an inner peripheral portion defining an orifice, and a radially expandable and compressible valve component, the valve component comprising an annular frame and a valve structure supported inside of the frame, wherein the valve component is configured to expand within the orifice of the sealing member and engage the inner peripheral portion of the sealing member when radially expanded.

The present technology relates to modular valve replacement systems for treating valve-related cardiac disorders. In select embodiments, the modular valve replacement system includes a fixation device and a permanent valve assembly configured to be assembled in vivo. The fixation device and the permanent valve assembly are delivered separately, enabling use of smaller delivery systems and facilitating less-invasive implant techniques. The fixation device is implanted first and provides a mounting fixture to which the permanent valve assembly is subsequently attached. In some embodiments, the fixation device includes a temporary valve assembly that prevents regurgitation until the permanent valve assembly is implanted. After the fixation device has been implanted, the permanent valve assembly can be inserted into the heart and attached to the fixation device. The permanent valve assembly can include a frame and a permanent prosthetic valve carried by the frame, and the frame can be configured to be securely connected to the fixation device while the fixation device and the permanent valve assembly are within the heart.

The terminology used in the description presented below is intended to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific embodiments of the present technology. Certain terms may even be emphasized below; however, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section. Additionally, the present technology can include other embodiments that are within the scope of the examples but are not described in detail with respect to <FIG>.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present technology. Furthermore, the particular features or characteristics may be combined in any suitable manner in one or more embodiments.

Reference throughout this specification to relative terms such as, for example, "substantially," "approximately," and "about" are used herein to mean the stated value plus or minus <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or less than <NUM>%.

As used herein, the term "fixation device" refers to an implantable medical apparatus that provides a mounting fixture for subsequent delivery and attachment of a valve assembly (e.g., a permanent valve assembly). The fixation device can optionally include a temporary valve assembly.

As used herein, the term "temporary valve assembly" refers to one or more features of a fixation device that at least partially reduce and/or mitigate regurgitation following implantation of the fixation device but before delivery of a permanent valve assembly.

As used herein, the terms "permanent valve assembly," "permanent valve device," "valve replacement assembly," "valve replacement device," and "valve assembly" refer to a structure having a prosthetic valve that is configured to be delivered to and securely attached to a previously implanted fixation device. Use of the term "permanent" does not require that the valve is indefinitely implanted. Rather, use of the term "permanent" simply distinguishes the "permanent valve assembly" from the temporary valve assembly. For example, a "permanent valve assembly" is one that is implanted and intended to remain in the patient after completing the procedure and the patient leaves the medical facility for as long as the modular valve replacement system functions adequately.

The headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed present technology.

The mitral valve controls the flow of blood between the left atrium and the left ventricle. In a healthy heart, the mitral valve is open during diastole and allows blood to flow from the left atrium to the left ventricle. The mitral valve closes during systole to prevent flow of blood from the left ventricle to the left atrium. As a result, the left ventricle contracts and pumps blood out via the aorta without pumping blood back into the left atrium. Failure of the mitral valve to prevent the backflow of blood from the left ventricle to the left atrium is known as mitral valve regurgitation. <FIG> is a side view of native mitral valve anatomy, <FIG> is a top view of native mitral valve anatomy, and <FIG> is a schematic illustration of the path of blood flow through a heart. As illustrated, the mitral valve is a bicuspid valve comprising an anterior leaflet AL and a posterior leaflet PL. A plurality of tendon-like fibrous structures called chordae tendineae CT attached to the ventricular side of the anterior and posterior leaflets prevent prolapse of the leaflets. The chordae tendineae CT are secured to papillary muscles PM projecting from the walls of the left ventricle LV. Referring to <FIG>, blood flows from the left atrium LA to the left ventricle LV via the mitral valve MV. Blood flows out of the left ventricle LV into the ascending aorta via the left ventricular outflow tract LVOT.

Transcatheter technologies to repair or replace the mitral valve (often referred to as TMVr and TMVR) seek to reduce the perceived risk of mitral valve replacement/repair procedures. For example, several existing techniques seek to deliver an interventional device using a catheter-based delivery system. However, there are many challenges in implementing catheter-based interventional devices to treat mitral regurgitation because of the complexity of the mitral valve anatomy and the wide variety of both the mitral valve anatomy and the disease state across individual patients. Additionally, existing mitral valve repair devices often result in incomplete restoration of mitral valve function.

A variety of transcatheter mitral valve replacement device systems have been developed. Existing valve replacement systems typically have an implantable device comprising an attachment structure and a prosthetic valve structure permanently attached to the attachment structure. The attachment structure secures and seals the device to the native valve, and the prosthetic valve replaces the function of the native leaflets.

In TMVR, the valve replacement device is delivered in a compressed state via a delivery catheter. Transcatheter delivery techniques include transapical, trans-septal, and transfemoral. <FIG> illustrates a transapical delivery technique and <FIG> illustrates a trans-septal delivery technique. These techniques are well described in the literature and have been used for other cardiologic procedures. These procedures are typically performed using fluoroscopic, echocardiographic, and other imaging guidance. In the catheter-based delivery techniques, a steerable guidewire is placed across the orifice of the mitral valve. The delivery catheter with a compressed interventional device is inserted and located at the annular region of the native valve. The interventional device is then released from the catheter where it self-expands or is expanded (e.g., via balloon expansion) to a deployed state in which it is in apposition with the native valve anatomy. The catheter is then removed from the patient.

The dimensions of valve replacement devices, particularly as loaded or compacted for delivery, are a substantial driver for the outer diameter (often referred to as "French size") of the catheter-based delivery device. The cross-sectional or radial dimensions of the valve replacement dimensions as loaded are often referred to as the packing density. Most existing TMVR systems, for example, require a transapical approach where a catheter is inserted between the ribs to enter the apex of the heart to deliver the interventional device. This is because existing TMVR systems have unique constraints to be effective in native mitral valves, which impact the shaft size and stiffness of the as-loaded device and delivery system. Transapical approaches, however, are often considered less desirable due to the degree of myocardial injury and the impact of a thoracotomy (i.e., the surgery to access the pleural space via between the ribs), and in particular for older patients in poor health.

<FIG> is a cross-sectional view of a valve replacement device <NUM> (referred to herein as "device <NUM>") having an attachment structure <NUM> and a valve structure <NUM> permanently attached to the attachment structure <NUM>. <FIG> illustrates the device <NUM> in the deployed state, although the attachment structure <NUM> and the valve structure <NUM> are also permanently attached before being deployed. The attachment structure <NUM> is configured to secure and seal the device <NUM> to the native anatomy. The attachment structure <NUM> can include fixation member <NUM> (e.g., fixation ring), fixation elements <NUM> (e.g., barbs) projecting from the fixation member <NUM>, and an atrial "brim" <NUM> extending from an upstream portion of the fixation member <NUM>. The valve structure <NUM> can include a valve support <NUM> and a prosthetic valve <NUM> attached to the valve support <NUM>. The device <NUM> is advantageous, for among other reasons, because the valve support <NUM> is mechanically isolated from the fixation member <NUM> so that a tri-leaflet valve can be used in the valve support <NUM>. The fixation member <NUM> securely retains the device at a desired location relative to the anatomy. However, the compressed cross-sectional and longitudinal dimensions of the combined structures of the attachment structure <NUM> and permanently attached valve structure <NUM> may limit implementation of the device <NUM>. For example, the outer diameter size of a delivery device capable of delivering device <NUM> may be too large for certain implant techniques. Additionally, the valve replacement device <NUM> is relatively stiff in the compacted state such that it is difficult to insert the device <NUM> through tight bends in the vasculature and to turn the device <NUM> within the atrium for properly positioning the device at the native mitral valve.

Accordingly, reducing the outer diameter of the delivery device would be advantageous to reduce trauma to the heart using a transapical approach, as well as reducing the size of the access opening and risk of bleeding out. Reducing the outer diameter of the delivery device would also enable other techniques for delivering the interventional device to the mitral valve, such as trans-septal or trans-atrial. Trans-septal techniques are considered advantageous because they reduce trauma to the heart and allow more peripheral access, and reducing procedure trauma is associated with improved patient outcomes and shortened recovery times.

Reducing the system stiffness of a loaded delivery device would also be beneficial to enable trans-septal or other less invasive techniques. For example, since catheter-based trans-septal techniques require the catheter make several tight bends to access the mitral valve, reducing the stiffness of the system enables the catheter to access the native mitral valve from more peripheral locations. Collectively, reducing the stiffness of the system and reducing the compressed diameter of the interventional device would reduce the outer diameter of the catheter shaft and/or increase the flexibility and bend radius of the loaded delivery system.

Additionally, the performance of existing TMVR devices is challenged by complexities of the mitral valve and surrounding anatomy. For example, the left ventricular outflow tract (LVOT) is often decreased or obstructed by existing TMVR devices or mitral surgical valves. This interferes with the flow out of the left ventricle and through the aortic valve to the aorta. Affecting the LVOT can occur if: (a) an interventional device protrudes too far into the left ventricle, (b) the interventional device is placed at such an acute angle relative to the LVOT that it causes systolic anterior motion (SAM) of the anterior mitral leaflet, and/or (c) the anatomy otherwise constricts or redirects the LVOT in such a way that it is impacted by the device (such as septal hypertrophy). Procedure pre-planning to assess the potential for LVOT obstruction is time-consuming, and the overall concern about LVOT obstruction potentially reduces the number of patients considered for TMVR utilizing current devices.

It is also challenging to anchor and seal existing replacement valve devices that are delivered via a catheter-based technique. The native mitral anatomy to which the interventional valve device is attached is a dynamic D-shaped structure with heterogenous stiffness. As such, this presents a difficult landing zone for anchoring and sealing interventional valve devices. The D-shaped asymmetry of the native mitral valve anatomy can also be problematic for creating a replacement valve that both maintains function as a directional valve and adequately seals to the surrounding asymmetrical anatomy.

Additionally, the asymmetry of the mitral valve anatomy, potential for LVOT obstruction, and potential for adjacent structure damage, such as chordae tendineae, collectively make it difficult to target the mitral valve and implant the interventional device at a desired angle and insertion depth relative to the native anatomy. These challenges can add to complexity of the TMVR valve device and the delivery system, as well as the procedure time required to place the valve.

Therefore, there remains a need for improved cardiac valve devices, especially mitral valve replacement devices and systems. The present technology is directed to interventional devices, systems, and methods. In particular, the present technology is related to improving function of cardiac valves, and more particularly treating mitral valve regurgitation. For example, select embodiments of the present technology provide TMVR devices that overcome one or more of the challenges discussed above. Some aspects of the present technology comprise a fixation device that can accept insertion or attachment of a separate permanent valve assembly. In some embodiments, the fixation device utilizes a temporary valve reinforcement or replacement. Some aspects of the present technology comprise a permanent valve assembly with features to aid in attachment or sealing to a fixation device. In modular systems of the present technology, the fixation device is delivered separately from the permanent valve assembly. For example, one catheter access can be used for delivery of the fixation device, and another catheter access can be used for delivery of the permanent valve assembly. This reduces the diameter of the device and packing density per access compared to devices in which the fixation device is attached to the prosthetic valve apparatus during delivery, which in turn reduces the catheter diameter and increases the bend radius.

<FIG> illustrate select aspects of modular valve replacement systems configured in accordance with the present technology. Additional features and aspects are described as well. As one skilled in the art will appreciate from the disclosure herein, features and aspects of any particular embodiment can be applied to or otherwise incorporated with any other embodiment described in <FIG>.

<FIG> illustrate a fixation device <NUM> configured in accordance with select embodiments of the present technology. The fixation device <NUM> can be implanted at or adjacent a native valve annulus to provide a mounting fixture for a subsequently delivered permanent valve replacement assembly, as described in greater detail below. Referring to <FIG>, the fixation device <NUM> includes an outer structure <NUM> having an upstream portion <NUM> and a downstream portion <NUM>. The outer structure <NUM> can be a stent-like structure comprising a plurality of struts <NUM>. The outer structure <NUM> can be a laser cut and molded structure, a braided structure, or any other suitable structure for forming a landing pad for a subsequently delivered valve assembly. The outer structure <NUM> can be formed from a shape-memory material, such as a nickel-titanium alloy, stainless steel, or another suitable material that is capable of self-expanding from a compressed delivery state to a desired expanded state shaped to engage the native mitral valve. In some embodiments, the downstream portion <NUM> has a greater rigidity or stiffness than the upstream portion <NUM>. For example, the downstream portion <NUM> can comprise a different material and/or comprise a number of stabilizing elements (not shown) to increase the rigidity of the downstream portion <NUM>. As will be described below with respect to <FIG>, the increased rigidity of the downstream portion <NUM> provides more structural support for supporting a permanent valve replacement assembly, while a more flexible upstream portion <NUM> can flex to more closely adapt to the shape of the native mitral valve. In some embodiments, both the downstream portion <NUM> and the upstream portion <NUM> have a rigidity suitable to secure a permanent valve replacement assembly.

The fixation device <NUM> can have a generally hourglass shape such that, in a deployed configuration, the upstream portion <NUM> and the downstream portion <NUM> flare radially outward relative to a narrow waist region <NUM>. When fixation device <NUM> is implanted at, for example, a native mitral valve annulus, the upstream portion <NUM> resides within a left atrium and the downstream portion <NUM> resides within a left ventricle. Accordingly, in some embodiments, the upstream portion <NUM> may be referred to as a "supra-annular portion" and the downstream portion <NUM> may be referred to as a "sub-annular portion. " In some embodiments, fixation device <NUM> can have another shape configured to substantially conform to a shape of a native valve annulus. In some embodiments, the fixation device <NUM>, and in particular at least one or both of the waist region <NUM> and the upstream portion <NUM>, comprises a malleable material that conforms to the native valve annulus upon deployment of the fixation device <NUM>. For example, the fixation device <NUM> can be self-expandable or balloon expandable to a number of different geometric configurations that permit tissue apposition at or adjacent the native valve annulus. The outer structure <NUM> is at least partially hollow such that fluid can flow through the fixation device <NUM> from the upstream portion <NUM> to the downstream portion <NUM>. Accordingly, fixation device <NUM> is configured such that blood flows through fixation device <NUM> from the upstream portion <NUM> to the downstream portion <NUM> as blood flows from the left atrium to the left ventricle.

<FIG> is a top view of the fixation device <NUM>. As illustrated, fixation device <NUM> can further include a temporary valve assembly <NUM>. The temporary valve assembly <NUM> includes a temporary valve <NUM>. In the illustrated embodiment, the temporary valve assembly <NUM> is a one-way valve comprising two flaps. However, as discussed in greater detail below, other valve-like elements can be included with the temporary valve assembly <NUM> in lieu of or in addition to the temporary valve <NUM>. For example, the temporary valve <NUM> can comprise a duckbill valve, bi-leaflet valve, tri-leaflet valve, or the like, and/or can be a thin membrane. The temporary valve assembly <NUM> is secured to the outer structure <NUM> at first attachment portion 526a and second attachment portion 526b. The temporary valve <NUM> can help maintain valve competence and prevent perivalvular leakage until later placement of the permanent valve replacement assembly.

<FIG> illustrates an assembled modular valve replacement system configured in accordance with select embodiments of the present technology. The assembled modular valve replacement system comprises the fixation device <NUM> and a permanent valve assembly <NUM>. The permanent valve assembly <NUM> can comprise a valve support <NUM> and a prosthetic valve <NUM>. In some embodiments, the valve support <NUM> can be a stent-like frame cut from a metal tube and/or a braided structure. For example, the valve support <NUM> can be made from a shape-memory laser cut tube or braid, such as a nickel-titanium alloy. As will be described in greater detail below with respect to <FIG>, the permanent valve assembly <NUM> can be transvascularly delivered and secured to the fixation device <NUM> after the fixation device <NUM> has been implanted at the native valve. Once secured to the fixation device <NUM>, the permanent valve assembly <NUM> can displace the temporary valve assembly <NUM> and function as the primary flow control mechanism. The prosthetic valve <NUM> can be a one-way valve configured to reduce and/or mitigate regurgitation. In some embodiments, the prosthetic valve <NUM> can be a bi-leaflet valve, a tubular bi-valve (e.g., an extension of a synthetic or bioprosthetic conduit comprising the permanent valve assembly <NUM>), a tri-leaflet valve, a duckbill valve, or any other suitable valve for controlling flow of blood within a heart. <FIG> is a bottom view of the permanent valve assembly <NUM> and illustrates a bi-leaflet prosthetic valve <NUM> positioned within the valve support <NUM>.

<FIG> is a schematic view after the fixation device <NUM> has been implanted at a native valve annulus A within a heart (e.g., the native mitral valve annulus). The fixation device <NUM> can at least partially conform to the native annulus A such that the upstream portion <NUM> contacts an atrial facing portion of the native annulus A, the downstream portion <NUM> contacts a ventricular facing portion of the native annulus A, and the waist region <NUM> is at inner rim of the annulus A. The anterior leaflet AL and the posterior leaflet PL are displaced by the fixation device <NUM>. <FIG> illustrates the fixation device <NUM> before the permanent valve assembly <NUM> is implanted. At this stage of a procedure before the permanent valve assembly <NUM> is implanted, the temporary valve assembly <NUM> (<FIG>) within the fixation device <NUM> maintains valvular competence until the permanent valve assembly <NUM> is implanted and secured to the fixation device <NUM>.

<FIG> illustrates the modular valve replacement system <NUM> after the permanent valve assembly <NUM> has been inserted and secured to the fixation device <NUM>. The permanent valve assembly <NUM> can be secured to an interior structure of the fixation device <NUM> and displaces the temporary valve assembly <NUM> (<FIG>). As a result, the prosthetic valve <NUM> controls the flow of blood through the annulus A.

<FIG> illustrates a modular valve replacement system <NUM> (hereinafter referred to as "system <NUM>") configured in accordance with select embodiments of the present technology. The system <NUM> can comprise a fixation device <NUM> and a permanent valve assembly <NUM> that can be configured to be delivered separately from each other and then attached together in vivo at a target site. The fixation device <NUM> can have an outer structure <NUM> that defines a first stent structure which provides (a) fixation to the native valve anatomy, (b) support for a temporary valve to temporarily prevent regurgitant flow while just the fixation device <NUM> is implanted, and (c) a structure to which the permanent valve assembly <NUM> can be attached in vivo.

The fixation device <NUM> can have an outer structure <NUM> and a temporary valve assembly <NUM> attached to the outer structure <NUM>. The outer structure <NUM> engages the native valve anatomy and subsequently supports the permanent valve assembly <NUM> within the native valve annulus. The outer structure <NUM> can be a self-expanding or balloon expandable first stent. For example, the outer structure <NUM> can be a cut tube or braid made from a shape memory material, such as a nickel-titanium alloy. In the embodiment illustrated in <FIG>, the outer structure <NUM> has an upstream portion <NUM>, a downstream portion <NUM>, and a tissue engagement portion <NUM> between the upstream portion <NUM> and the downstream portion <NUM>. The tissue engagement portion <NUM> can be a ring having a suitable shape (e.g., cylindrical or D-shaped) configured to engage and exert a radially outward force against the native annulus and/or the native leaflets. The outer structure <NUM> can further include fixation elements <NUM> projecting from the tissue engagement portion <NUM> that upon deployment engage the native tissue to further secure the fixation device <NUM> to the native anatomy.

The temporary valve assembly <NUM> can include an inner structure <NUM> configured to fit within the outer structure <NUM>. The temporary valve assembly <NUM> can further include a temporary prosthetic valve <NUM> attached to the inner structure <NUM>. In the embodiment illustrated in <FIG>, the inner structure <NUM> forms a generally toroidal-shaped chamber <NUM> that can be filled with blood through apertures <NUM> and/or the porosity of the material from which the inner structure <NUM> is made. The inner structure <NUM> can be made from a flexible material that is attached to the outer structure <NUM>. For example, the inner structure <NUM> can be made from a metal braid, polymeric materials (e.g., DACRON®), or other suitable biocompatible materials. The temporary prosthetic valve <NUM> can be a simple, thin structure that is configured to be displaced by the permanent valve assembly <NUM>, as explained in more detail below.

The outer structure <NUM> can be symmetrical (e.g., cylindrical) as noted above such that the tissue engagement portion <NUM> deforms to engage the D-shaped mitral annulus. Alternatively, the outer structure <NUM> can be asymmetrical such that the outer structure <NUM> is at least partially pre-shaped to approximate the shape and contour of the mitral annulus. For example, the outer structure can a D-shape (e.g., kidney shaped). This would have the advantage of limiting the deformation of the native valve. In particular, it would limit the deformation of the anterior leaflet and aorto-mitral curtain into the left ventricular outflow tract.

The tissue engagement portion <NUM> is designed and shaped to engage the mitral annulus and/or the native mitral leaflets. It can be somewhat oversized relative to the annulus so that when it is deployed it engages and presses against the annulus. The tissue engagement portion <NUM> can be a stent with struts that define multiple diamond-shaped openings between the struts so that in the deployed state the tissue engagement portion <NUM> exerts an appropriate radial outward force against the native anatomy. The tissue engagement portion can alternatively be a braided portion made from nickel-titanium alloy wires with sufficient strength to apply the desired force against the annulus. The fixation elements <NUM> can be cleats or spikes to further engage the annulus, and in particular to resist migration of the device into the atrium under systolic ventricular blood pressure. The fixation elements <NUM> can extend directly outward and atrially, or they can be curved as shown in <FIG> so that they can be folded flat as the device is resheathed, if necessary. The tissue engagement portion <NUM> can also have a layer of fabric (not shown) attached to it to form a fluid seal with the annulus and to accelerate the integration of the device into the annulus wall during the healing process. The fabric can comprise a material suitable to promote tissue ingrowth.

The downstream portion <NUM> of the outer structure <NUM> extends from the tissue engagement portion <NUM> radially inward and distally (e.g. downstream) so that the distal end of the downstream portion <NUM> has a smaller inner diameter than the tissue engagement portion <NUM>. The region of the downstream portion <NUM> that extends radially-inward can also have a layer of fabric (not shown) attached to it so that it will form a smooth surface to prevent clot formation over time. This fabric can be porous or have holes in it, so that blood under ventricular pressure fills the toroidal chamber <NUM> of the inner structure <NUM>.

The distal end <NUM> of the downstream portion <NUM> is shaped so that the downstream-most end of the fixation device <NUM> forms a circular, cylindrical surface. The radially-inward-extending region of the downstream portion <NUM> of the outer structure <NUM> may have differing lengths and/or differing angles around the circumference of the stent so that it can transition from the D-shaped tissue engaging portion <NUM> to the circular distal end <NUM>, as described below with respect to <FIG>. In some embodiments, this structure can be achieved by forming the final diamond-shaped strut structure at this end of the outer structure <NUM> free from the adjacent proximal diamond structure and shaped such that they extend this cylindrical surface proximally.

The cylindrically shaped surface formed by the downstream portion <NUM> of the fixation device <NUM> has at least three functions. First, the downstream portion <NUM> retains the cylindrically-shaped inner structure <NUM> that defines a fabric tube which forms the chamber <NUM> of the temporary valve assembly <NUM>. This tubular fabric extends in an atrial direction and then flares radially outward to join the atrial end of the tissue engagement portion <NUM> of the outer structure <NUM>, as shown in <FIG>. This fabric encloses the inner and atrial surfaces of the toroidal volume of the chamber <NUM>. The chamber <NUM> is a relatively sealed chamber such that it can be inflated with blood upon deployment of the fixation device via apertures <NUM> and/or the porosity of fabric (e.g., on the ventricular end of the chamber <NUM>).

Second, the cylindrical downstream portion <NUM> can form the attachment points for the commissures of the temporary valve <NUM>. If it is desired to make the temporary valve assembly <NUM> symmetrical with a three-leaflet valve, then the outer structure <NUM> can comprise a number of diamond-shaped stent elements around its circumference as a multiple of three so that these commissural connections align with the stent elements. The temporary prosthetic valve <NUM> is sutured to the inner wall of the cylindrical fabric tube that defines the inner structure <NUM>. The commissural suturing can project these leaflets somewhat radially towards the center of the valve so they will close predictably even after being compressed for delivery.

Third, the distal end <NUM> of the downstream portion <NUM> can be cylindrical to provide structure to which the permanent valve assembly <NUM> is attached after the permanent valve assembly <NUM> has been delivered separately from the outer structure <NUM>. The downstream portion <NUM> can include specific features which engage specific features on the permanent valve assembly <NUM>, or the permanent valve assembly <NUM> may simply flare outward at its distal end to engage the downstream portion <NUM>.

The upstream portion <NUM> (i.e., proximal end) of the outer structure <NUM> extends radially inward from the upstream end of the tissue engagement portion <NUM>. In some embodiments, it may be preferable for the upstream portion <NUM> to be shaped such that it extends somewhat towards the ventricle as it extends radially inward, as shown in <FIG>. This way, when the permanent valve assembly <NUM> is placed inside it, any force on the valve due to systolic ventricular pressure will tend to drive the tissue engagement portion <NUM> outward against the native mitral annulus, rather than pulling it inward. The portion of the inner structure <NUM> that flares radially outward may end up laying against the upstream portion <NUM> of the outer structure <NUM>.

The upstream-most and inner-most portion <NUM> of the upstream portion <NUM> bends upward (e.g., proximally), extending atrially in a generally cylindrical shape. This cylindrical surface can form a landing for the permanent valve assembly <NUM>. This proximal end of the outer structure <NUM> can also have capture features <NUM> to releasably connect the fixation device <NUM> to a delivery system (not shown). The capture features <NUM> make it easier to recapture and recompress the fixation device <NUM> if necessary. In some embodiments, the upstream portion of the tissue engagement element <NUM>, as well as the radially-inward-extending upstream portion <NUM>, may be somewhat more flexible than the middle and distal portions of the fixation device <NUM>, making recapture of the fixation device <NUM> easier. The outer structure <NUM> can further include first and second attachment portions <NUM> and <NUM> for securely attaching the permanent valve assembly <NUM> to the fixation device <NUM>. The first attachment portion <NUM> is at the upstream portion <NUM> and the second attachment portion <NUM> is at the distal end <NUM> of the downstream portion <NUM>. The first attachment portion <NUM> can include specific features which engage specific features on the permanent valve assembly <NUM>, or the permanent valve assembly <NUM> may simply flare outward at its proximal end to engage the first attachment portion <NUM>.

It some embodiments, it can be easier to compress and deliver the fixation device <NUM> if the total length of the proximal segments of the fixation assembly (including the upstream portion <NUM> that extends radially inward from the tissue engagement portion <NUM> and the atrially-directed upstream-most end) are all of the same length. This is the case because both the upstream portion <NUM> of the outer structure <NUM> and the connectors to the delivery system are not skewed when compressed. The lengths and angles of the proximal segments of the fixation device <NUM> may vary around the circumference of the fixation device <NUM> to achieve this, as well as to transition from a D-shaped region defined by the tissue engagement portion <NUM> to a circular cylindrical region defined by the upstream most end of the upstream portion <NUM>.

<FIG> (bottom panel) shows a side view of the permanent valve assembly <NUM>. In some embodiments, the permanent valve assembly <NUM> is a tri-leaflet valve commonly used for transcatheter valve prostheses with a diameter of about <NUM>-<NUM>. The permanent valve assembly <NUM> is configured to be delivered to the target site separately from the fixation device <NUM> and subsequently attached to the fixation device <NUM> in vivo. The permanent valve assembly <NUM> can include a valve support <NUM>, which can be a cylindrical second stent structure that is either self-expanding or balloon-expandable. For example, the valve support <NUM> can be a cut tube or braided wire made from a nickel-titanium alloy or outer suitable biocompatible material. The valve support <NUM> can be slightly larger in diameter than the proximal and distal cylindrical segments of the outer structure <NUM>. This will cause the valve support <NUM> to exert a radially outward force against the outer structure <NUM>, which in turn will drive the outer structure <NUM> radially outward and further drive the tissue engagement portion <NUM> against the native annulus. As the heart beats, the systolic forces against the valve will push it towards the atrium. This force will be transferred to the distal and proximal radially-inward-extending portions of the outer structure <NUM>, which will then further drive the tissue engagement portion <NUM> against the mitral annulus. The valve support <NUM> can further include first engagement elements <NUM> configured to engage the first attachment portion <NUM> of the outer structure <NUM>, and second engagement elements <NUM> configured to engage the second attachment portion <NUM> of the outer structure <NUM>. However, in other embodiments, the valve support is secured to the fixation device via single attachment interface.

When deployed within the fixation device <NUM>, the permanent valve assembly <NUM> can remain mechanically isolated from the outer structure <NUM>. Accordingly, deforming the outer structure <NUM> (e.g., to conform to native anatomy or in response to contraction of the heart) will not impart substantial force upon the permanent valve assembly <NUM> and therefore will not substantially affect the integrity of the valve <NUM>.

The permanent valve assembly <NUM> further includes a permanent prosthetic valve <NUM> and a skirt <NUM>. The skirt <NUM> and the permanent prosthetic valve <NUM> are attached to the valve support <NUM>. The permanent prosthetic valve <NUM> can be a tri-leaflet valve, or any other suitable valve, such as a duckbill valve and/or a bi-leaflet valve.

In operation, the fixation device <NUM> is contained in a compressed state (e.g., a delivery configuration) in a delivery system. The fixation device <NUM> is not connected to the permanent valve assembly <NUM> when the fixation device <NUM> is in the compressed state. While the fixation device <NUM> is delivered to and deployed at the target location (e.g., at the native mitral valve), it is not coupled to the permanent valve assembly <NUM>. The fixation device <NUM> is accordingly deployed separately from the permanent valve assembly <NUM>. After the fixation device <NUM> has been implanted at the native valve annulus in a deployed or expanded state, but before the permanent valve assembly <NUM> is deployed, the temporary valve <NUM> of the temporary valve assembly <NUM> controls blood flow through the target valve (e.g., the mitral valve) during systole and diastole. The permanent valve assembly <NUM> is then deployed within the outer structure <NUM> such that the first and second engagement elements <NUM> and <NUM> engage the first and second attachment portions <NUM> and <NUM>, respectively. As this occurs, the valve support <NUM> displaces the temporary valve <NUM> and presses radially outward against the outer structure <NUM>. The combination of the first and second engagement elements <NUM> and <NUM> and the radially outward force between the valve support <NUM> and the outer structure <NUM> securely attaches the permanent valve assembly <NUM> to the outer structure <NUM>. Additionally, since the fixation device <NUM> and the permanent valve assembly <NUM> are delivered and implanted independently of each other, they individually have a smaller compressed diameter compared to a device in which they are attached to each other before being loaded into a delivery catheter (e.g., such as the device <NUM> described above). This is expected to reduce the outer diameter of the delivery catheter and increase the flexibility and bend radius of the delivery system to enable peripherally-based delivery techniques, such as trans-septal or trans-atrial.

<FIG> illustrate additional aspects of a modular valve replacement system configured in accordance with select embodiments of the present technology. Referring to <FIG>, the modular valve replacement system can include a fixation device <NUM> configured to engage native tissue via sub-annular oversizing, radial force, and/or frictional elements (e.g., fixation elements <NUM>). The fixation device <NUM> can be lined with a fabric (e.g., PET) skirt to provide sealing and a platform for ingrowth. As will be described in greater detail below, the fixation device <NUM> also has features that engage with the structure of a permanent valve assembly.

Referring to <FIG>, fixation device <NUM> includes a tissue engagement portion <NUM>, valve support arms <NUM>, and fabric support arms <NUM>. The valve support arms <NUM> and the fabric support arms <NUM> extend from a downstream portion of the tissue engagement portion <NUM>. In some embodiments, the valve support arms <NUM> and fabric support arms <NUM> are integral with the tissue engagement portion <NUM> such that together they form a unitary structure. In other embodiments, the valve support arms <NUM> and/or the fabric support arms <NUM> and the tissue engagement portion <NUM> are distinct elements that are otherwise coupled together. The tissue engagement portion <NUM> can include one or more fixation elements <NUM> to help secure the fixation device <NUM> at or adjacent the native annulus.

The valve support arms <NUM> extend radially inward from the downstream portion of the tissue engagement portion <NUM> in a similar fashion as described above with respect to the downstream portion <NUM> of the outer structure <NUM> illustrated in <FIG>. The valve support arms <NUM> can be generally curved such that they form a substantially cylindrical center lumen configured to receive a permanent valve assembly. For example, in some embodiments, the valve support arms <NUM> define a substantially cylindrical center lumen with an inner diameter of about <NUM>-<NUM>. To form the substantially cylindrical center lumen, individual valve support arms may have varying lengths and/or curvatures to account for a non-circular outer shape of the fixation device <NUM>.

The fabric support arms <NUM> extend generally downstream from the tissue engagement portion <NUM>. As noted above, the fabric support arms <NUM> can simply be a downstream extension of the tissue engagement portion <NUM>. In some embodiments, the fabric support arms <NUM> can be at least slightly curved and/or deformable such that they conform to native tissue. In some embodiments, the fabric support arms <NUM> extend radially inward at least partially such that they do not contact native tissue. In such embodiments, the fabric support arms <NUM> extend radially inward at a less acute angle than the valve support arms <NUM>.

A fabric web <NUM> can extend between the downstream end portions of the valve support arms <NUM> and the downstream end portions of the fabric support arms <NUM>. The fabric web <NUM> acts in tension under a ventricular pressure load to provide stability to the valve support arms <NUM>. The valve support arms <NUM> and the fabric support arms <NUM> can also be lined with fabric to create an enclosed toroidal volume that can fill with blood <NUM> after implanting the fixation device <NUM> (see <FIG>). These blood-filled volumes could eventually form solid thrombus or other healing response that can provide additional stabilization of the fixation device <NUM>. Moreover, the added stability provided to the valve support arms by the fabric web and the enclosed blood volume could allow for thinner structural elements. This can additionally reduce the pack down density without compromising structural integrity.

The fixation device <NUM> can have a temporary valve <NUM>. In some embodiments, the temporary valve <NUM> can be generally similar to the temporary valve <NUM> described with respect to <FIG>. For example, the temporary valve <NUM> can be made from a thin polymer material, such as ePTFE, that prevents full or partial backflow or regurgitation from the left ventricle to the left atrium, thereby reducing harmful buildup of pressure in the pulmonary system or damage to the heart.

<FIG> depicts a flat pattern of the fixation device <NUM>. In some embodiments, this structure is cut from a Nitinol tube and is expandable to the shape shown in <FIG>. The atrial end of the structure forming the tissue engagement portion <NUM> has a diamond pattern and fixation elements <NUM> that engage with the native annulus and provide fixation. A plurality of upstream capture features 935a extend atrially from the tissue engagement portion <NUM>. The upstream capture features 935a can releasably connect the fixation device <NUM> to a delivery system (not shown). The upstream capture features 935a therefore make it easier to recapture and recompress the fixation device <NUM>, if necessary. The midsection of the structure includes the valve support arms <NUM> and fabric support arms <NUM>. The distal ends of the valve support arms <NUM> and the fabric support arms <NUM> are connected via the fabric web (not shown). The ventricle end of the structure can include a plurality of downstream capture features 935b to further facilitate recapture of the fixation device <NUM>, if necessary.

As illustrated in <FIG>, the fixation device <NUM> does not include a permanent valve assembly. The modular approach therefore allows for delivery of the fixation apparatus separately from the permanent replacement valve, thus reducing the material that is packed within a given delivery catheter. This reduces maximum packing density and reduces the required catheter size.

<FIG> depicts the fixation device <NUM> implanted in a heart and with a permanent valve assembly <NUM> engaged within the valve support arms <NUM>. The permanent valve assembly <NUM> includes a valve support <NUM> and a prosthetic valve <NUM>. The valve support <NUM> is secured to the fixation device <NUM> via the valve support arms <NUM> (e.g., through oversizing, radial force, and/or friction). The valve support <NUM> also supports the prosthetic valve <NUM>, which controls the flow of blood between the left atrium and the left ventricle to reduce and/or mitigate regurgitation. As the permanent valve assembly <NUM> is attached to the fixation device <NUM>, the valve support <NUM> displaces the temporary valve <NUM>. In some embodiments, the permanent valve assembly <NUM> may be delivered from the atrial side through the same guide used to advance the delivery system of the fixation apparatus.

<FIG> are side views of a modular valve replacement system related to the embodiment described with respect to <FIG>. The modular valve replacement system includes a fixation device <NUM> having valve support arms <NUM> and fabric support arms <NUM>. The valve support arms <NUM> can be radially over or undersized to define a central lumen having a diameter of D<NUM> (e.g., about <NUM>-<NUM> or less). The lumen can be undersized in relation to the permanent valve assembly <NUM> such that insertion of the permanent valve assembly <NUM> creates regioselective radial force on the valve support arms <NUM>, transitioning the fixation device <NUM> to a second diameter D<NUM> greater than the first diameter D<NUM>. Such regioselective radial forces can (a) enhance the fixation or sealing between the permanent valve assembly <NUM> and the fixation device <NUM>, and/or (b) be transferred through the fixation device <NUM> to regioselectively enhance attachment or sealing force between the fixation device <NUM> and the native tissue.

<FIG> depict aspects of permanent valve assemblies that could enhance the attachment or sealing of the permanent valve assembly to the fixation assembly in any of the embodiments described herein. <FIG> shows a simplified side view of a permanent valve assembly <NUM> including a valve support <NUM> and a prosthetic valve <NUM>. The valve support <NUM> can include a number of features that secure the permanent valve assembly <NUM> to a previously implanted fixation device (e.g., fixation devices <NUM>, <NUM>, <NUM> and/or <NUM>). For example, the valve support <NUM> can include a proximal end portion <NUM> and distal end portion <NUM> that curve radially outward to engage with complimentary curved structures on the fixation device to prevent longitudinal movement of the valve and potentially enhance sealing between the permanent valve assembly <NUM> and the fixation device. As another example, the valve support <NUM> can include hydrogel or elastomer rings or components <NUM> that enhance sealing or attachment to the fixation device. As yet another example, the valve support <NUM> can include barbed or other rigid or semi-rigid fixation elements <NUM> to enhance attachment to the fixation apparatus. The permanent valve assemblies described herein can have one or more of the above features to help secure the permanent valve assembly to the fixation device.

The permanent valve assemblies described herein can also be secured to the fixation devices via regioselective forces. <FIG> shows a side view of permanent valve assemblies 1150a and 1150b (collectively referred to as "valve assemblies 1150a-b") that can be secured to the fixation devices using regioselective forces. The valve assemblies 1150a-b include respective valve supports 1160a-b and respective prosthetic valves 1170a-b. In <FIG>, the valve assemblies 1150a-b are depicted in a fully unconstrained state in which valve supports 1160a-b have a conical shape. <FIG> depicts the permanent valve assemblies 1150a-b in a constrained state that they would have when deployed within the fixation device. In lieu of or in addition to the shape of the valve support 1260a-b, regioselective force could similarly be imparted by utilizing stiffer nitinol structures or doubling up stent structures in certain regions.

<FIG> shows side views of additional permanent valve assemblies configured to provide regioselective forces on the fixation device when deployed within the fixation device. For example, permanent valve assemblies 1150c-f can have valve supports 1160c-f with various nonlinear shapes in a fully unconstrained state. When deployed within a fixation device in a constrained state, the valve supports 1160c-f may be prevented from fulling expanding to their unconstrained state, thereby imparting regioselective forces on and securing the valve supports to the fixation device. In some embodiments, the fixation apparatus can have complimentary profiles to improve sealing and attachment of the valve supports, and potentially targeting and depth assessment of the permanent valve relative to the fixation apparatus.

Additional techniques can also be utilized to further secure the permanent valve assembly to the fixation device. For example, once the permanent valve assembly is deployed within the fixation device, a biocompatible polymer or hydrogel (e.g., PEG) can be injected into the volume between the permanent valve assembly and the fixation apparatus to seal the permanent valve to the fixation device and promote attachment.

<FIG> illustrate yet another fixation device <NUM> configured in accordance with select embodiments of the present technology. Referring to <FIG> and <FIG>, the fixation device <NUM> includes an outer structure <NUM> and a temporary flow restriction element <NUM>. Rather than having a bi-leaflet valve, the temporary flow restriction element <NUM> includes a single moveable element or flap, such as prosthetic leaflet <NUM>. The prosthetic leaflet <NUM> is coupled to a distal (e.g., ventricular) surface <NUM> of the fixation device <NUM> and may be moveable or fixed, but is shaped and positioned such that it coapts with a native anterior leaflet when implanted. <FIG> illustrates the area of the mitral valve (e.g., the posterior leaflet) that would be supplanted by the prosthetic leaflet <NUM>. Returning to <FIG>, the prosthetic leaflet <NUM> can include a clip <NUM>. The clip <NUM> can engage the native leaflet (e.g., the posterior leaflet) blocked by the prosthetic ventricular surface <NUM>. Engaging the native leaflet with the clip <NUM> may help to prevent systolic anterior motion of the native leaflet, and may reduce impingement of the native leaflet and or fixation device <NUM> into the LVOT. The fixation device <NUM> can also include valve support arms in which the permanent replacement valve can be engaged (not shown). This system minimizes LVOT obstruction and does not require a temporary valve on the fixation apparatus, another way to potentially additionally reduce packing density.

The modular valve replacement system further includes a permanent valve assembly <NUM> that is attached to the fixation device <NUM> after the fixation device <NUM> has been implanted in the heart. The permanent valve assembly <NUM> can include valve support <NUM> and prosthetic valve <NUM>. The permanent valve assembly <NUM> can be substantially similar to the permanent valve assemblies described herein. Referring to <FIG>, permanent valve assembly <NUM> can be secured to the fixation device <NUM> via regioselective forces. For example, the fixation device <NUM> can have a narrowed orifice with a first diameter D<NUM> when the valve assembly <NUM> is separate from the fixation device <NUM>. This could potentially reduce the interference with coaptation of the native anterior leaflet until the permanent valve assembly <NUM> is deployed and exert more radial outward force against the fixation device <NUM>. This enhances the fixation and sealing both between the permanent valve assembly <NUM> and the fixation device <NUM>, and the fixation device <NUM> and the surrounding native mitral valve area. As illustrated in <FIG>, the fixation device <NUM> engages the atrial wall via radial force and frictional elements. <FIG> illustrates the fixation device <NUM> and the permanent valve assembly <NUM> implanted in the heart.

<FIG> illustrate a modular valve replacement system deployable above a native valve annulus (e.g., within a left atrium above a mitral valve annulus) in accordance with select embodiments of the present technology. <FIG> illustrates a fixation device <NUM> having a lumen <NUM>. Although illustrated as a simple toroidal sphere, the fixation device <NUM> can comprise any configuration substantially similar to configurations described herein for other fixation devices, and it can include additional elements as discussed herein. Referring to <FIG>, the fixation device <NUM> is deployed above the native valve annulus and secured within the left atrium. As a result, the fixation device <NUM> does not contact the native leaflets, and thus a temporary valve assembly is not needed to control blood flow following implantation of the fixation device <NUM> but before delivery of the permanent valve assembly.

Referring to <FIG>, a permanent valve assembly <NUM> can be subsequently delivered to and deployed within the fixation device <NUM>. The permanent valve assembly <NUM> also sits within the left atrium and therefore does not interfere with the native leaflets. Accordingly, the permanent valve assembly <NUM> supplements the functioning of the native leaflets. While <FIG> illustrate a specific modular valve replacement system, one skilled in the art will understand that any of the modular valve replacement systems described herein, including the various features and designs of the fixation devices and permanent valve assemblies, can be configured to avoid interfering with the native valve leaflets by being deployed and secured above the native leaflets (e.g., the left atrium above the mitral valve). This embodiment would not require temporary valve leaflets, another way to reduce packing density.

<FIG> is a top view of a fixation device <NUM> configured in accordance with select embodiments of the present technology. The fixation device <NUM> can include an outer structure <NUM> and a plurality of valve support arms <NUM>. The plurality of valve support arms <NUM> can define a generally cylindrical central lumen <NUM> to which a separately delivered permanent valve assembly (not shown in <FIG>) can be subsequently attached. The outer structure <NUM> can have a kidney bean-like shape. As a result, the outer structure <NUM> has two protrusions or horns <NUM> that protrude to engage with native asymmetric anatomy. For example, the horns <NUM> can be oriented towards the anterior side of the native valve to engage the annulus at the trigones. This is expected to enhance fixation of the fixation device <NUM> to the native anatomy. The relief between the horns <NUM> at the center of the anterior side of the annulus may also reduce the protrusion of the structure into the left ventricular outflow tract (LVOT) and thereby reduce the potential for LVOT obstruction. These asymmetrical shapes can be in any plane of the device and provide benefit for fixation, and in any portion of the device in the left ventricle and provide benefit in reducing LVOT obstruction. Due to the asymmetrical shape of the outer structure <NUM>, individual valve support arms of the plurality of valve support arms <NUM> can comprise different lengths and/or shapes. This enables the outer shape to be asymmetrical while the central lumen <NUM> remains substantially cylindrical. After the fixation device <NUM> has been implanted, any of the permanent prosthetic valves described above can be attached to the fixation device <NUM> in vivo.

The modular nature of the present technology facilitates transvascular implant approaches. For example, by separating the fixation device from the permanent valve assembly before implantation, the compressed size of the fixation device can be smaller than the combination of compressing both the fixation device and the permanent valve assembly together. For example, in some embodiments, the fixation device can be compressed to approximately <NUM> Fr to approximately <NUM> Fr, or approximately <NUM> Fr to proximally <NUM> Fr, or approximately <NUM> Fr to approximately <NUM> Fr. This enables the implantation of the fixation device in a low-profile configuration having a size less than about <NUM> Fr, <NUM> Fr, <NUM> Fr, <NUM> Fr, <NUM> Fr, <NUM> Fr, <NUM> Fr, <NUM> Fr, <NUM> Fr, and/or 18Fr, which in turn enhances the ability to plant the fixation device using, for example, a trans-septal approach. The permanent valve assembly can be compressed to any of the foregoing sizes of the fixation device, although the permanent valve assembly is also often compressed to smaller sizes than those listed above for the fixation device. The fixation device can accordingly be implanted first and independently of the permanent valve assembly such that the fixation device can be readily implanted at the mitral valve annulus using a trans-septal approach. The permanent valve assembly can then be positioned at the fixation device and secured thereto in vivo.

Although many of the embodiments are described above with respect to systems, devices, and methods for treating cardiac disease, the technology is applicable to other applications and/or other approaches, such as other cardiac valve applications. Moreover, other embodiments in addition to those described herein are within the scope of the technology. Additionally, several other embodiments of the technology can have different configurations, components, or procedures than those described herein. A person of ordinary skill in the art, therefore, will accordingly understand that the technology can have other embodiments with additional elements, or the technology can have other embodiments without several of the features shown and described above with reference to <FIG>.

The above detailed descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Where the context permits, singular or plural terms may also include the plural or singular term, respectively. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.

Moreover, unless the word "or" is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of "or" in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the term "comprising" is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.

Claim 1:
A modular valve replacement system (<NUM>) implantable into a heart using a catheter-based implantation system, the modular valve replacement system (<NUM>) comprising:
a fixation device (<NUM>; <NUM>) including:
an outer structure (<NUM>) having a tissue engagement portion (<NUM>; <NUM>), an upstream portion (<NUM>), and a downstream portion (<NUM>), wherein the tissue engagement portion (<NUM>) is configured to engage native heart tissue when the fixation device (<NUM>) is deployed within the heart to independently secure the fixation device (<NUM>) to the native heart tissue, and
a temporary valve assembly (<NUM>) including (a) an inner structure (<NUM>) having a generally toroidal shape when the fixation device (<NUM>) is in the deployed configuration, wherein the inner structure (<NUM>) includes a chamber (<NUM>) configured to receive blood when the fixation device (<NUM>) is implanted at or adjacent the native valve annulus, and (b) a temporary prosthetic valve (<NUM>; <NUM>) attached to the inner structure (<NUM>); and
a permanent valve assembly (<NUM>; <NUM>) having a valve support (<NUM>; <NUM>) and a prosthetic valve (<NUM>; <NUM>) attached to the valve support (<NUM>), wherein the permanent valve assembly (<NUM>) is separate from the fixation device (<NUM>) in a low-profile state for delivery via a catheter and configured to be connected to the fixation device (<NUM>) in vivo after the fixation device (<NUM>) has been deployed within the heart, and the valve support (<NUM>) is spaced inwardly apart from the tissue engagement portion (<NUM>) when the permanent valve assembly (<NUM>) is attached to the fixation device (<NUM>) in vivo.