Leaflet engagement elements and methods for use thereof

The present invention relates to apparatus for methods for endovascularly replacing a patient's heart valve. The apparatus includes an expandable anchor with leaflet engagement elements on the proximal end of the anchor and a replacement valve. The leaflet engagement elements can be used to prevent distal migration and insure proper positioning of the apparatus.

BACKGROUND OF THE INVENTION

The present invention relates to methods and apparatus for endovascularly replacing a heart valve. More particularly, the present invention relates to methods and apparatus for endovascularly replacing a heart valve with a replacement valve using an expandable and retrievable anchor.

Heart valve surgery is used to repair or replace diseased heart valves. Valve surgery is an open-heart procedure conducted under general anesthesia. An incision is made through the patient's sternum (sternotomy), and the patient's heart is stopped while blood flow is rerouted through a heart-lung bypass machine.

Valve replacement may be indicated when there is a narrowing of the native heart valve, commonly referred to as stenosis, or when the native valve leaks or regurgitates. When replacing the valve, the native valve is excised and replaced with either a biologic or a mechanical valve. Mechanical valves require lifelong anticoagulant medication to prevent blood clot formation, and clicking of the valve often may be heard through the chest. Biologic tissue valves typically do not require such medication. Tissue valves may be obtained from cadavers or may be porcine or bovine, and are commonly attached to synthetic rings that are secured to the patient's heart.

Valve replacement surgery is a highly invasive operation with significant concomitant risk. Risks include bleeding, infection, stroke, heart attack, arrhythmia, renal failure, adverse reactions to the anesthesia medications, as well as sudden death. 2-5% of patients die during surgery.

Post-surgery, patients temporarily may be confused due to emboli and other factors associated with the heart-lung machine. The first 2-3 days following surgery are spent in an intensive care unit where heart functions can be closely monitored. The average hospital stay is between 1 to 2 weeks, with several more weeks to months required for complete recovery.

In recent years, advancements in minimally invasive surgery and interventional cardiology have encouraged some investigators to pursue percutaneous replacement of the aortic heart valve. However, the current devices suffer from several drawbacks.

First, many of the devices available today can become mispositioned with respect to the native valve. This is a critical drawback because improper positioning too far up towards the aorta risks blocking the coronary ostia of the patient. Furthermore, a misplaced stent/valve in the other direction (away from the aorta, closer to the ventricle) will impinge on the mitral apparatus and eventually wear through the leaflet as the leaflet continuously rubs against the edge of the stent/valve.

Moreover, some stent/valve devices simply crush the native valve leaflets against the heart wall and do not engage the leaflets in a manner that would provide positive registration of the device relative to the native position of the valve. This increases an immediate risk of blocking the coronary ostia, as well as a longer-term risk of migration of the device post-implantation.

Another drawback of the devices known today is that during implantation they may still require the patient to be on life support as the valve does not function for a portion of the procedure. This further complicates the implantation procedure.

Furtherstill, the stent comprises openings or gaps, thereby increasing a risk of improper seating of the valve within the stent and increasing the risk of paravalvular leaks. The interface between the stent and the native valve may additionally comprise gaps which again would increase the risks of paravalvular leaks.

In view of drawbacks associated with previously known techniques for endovascularly replacing a heart valve, it would be desirable to provide methods and apparatus that overcome those drawbacks.

SUMMARY OF THE INVENTION

One aspect of the invention provides an apparatus for endovascularly replacing a patient's heart valve. The apparatus includes: an expandable anchor and a replacement valve, wherein both are adapted for percutaneous delivery and deployment. The expandable anchor further includes a leaflet engagement element on its proximal end to engage the leaflets of the patient's heart valve. When the leaflets engagement element is engaged, the anchor is substantially distal to the coronary ostia of the patient. Moreover, once engaged, the leaflet engagement element prevents the distal movement of the anchor. In some embodiments, the leaflet engagement element is integral with the anchor or part of the anchor (especially when the anchor is an anchor braid). In other embodiments, the leaflet engagement element is attached to the proximal end of the anchor. In any of the embodiments herein, the anchor may be adapted for active foreshortening during deployment. Active foreshortening can occur by actuating the proximal and/or distal actuation elements of the anchor. The anchor herein may also be configured for locking and may include a locking element. The replacement valve of the apparatus herein is situated within the anchor and is adapted to permit blood flow and prevent blood backflow both during and after deployment.

Another aspect of the invention provides a method for endovascularly replacing a patient's heart valve. In some embodiments the method includes the steps of: endovascularly delivering an anchor comprising a leaflet engagement element on its proximal end and a replacement valve supported within the anchor to a vicinity of the heart valve in a collapsed delivery configuration; unsheathing the anchor allowing it to take a relaxed configuration intermediate between its sheathed and expanded configurations; expanding the anchor; and, engaging the leaflet engagement element with the native leaflets. The expanding step may further comprise actively foreshortening the anchor. Active foreshortening can include actuating proximal and/or distal actuation elements of the anchor. The method may also include the step of locking the anchor after it is in its deployed configuration. In some embodiments, when the anchor engages the patient's heart, the anchor is substantially distal to the coronary ostia. In any of the embodiments herein, leaflet engagement element prevents the anchor from distally migrating at its proximal end.

INCORPORATION BY REFERENCE

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an apparatus and methods for endovascularly delivering and deploying an aortic prosthesis within a patient's native heart valve, referred to here out as “replacing” a patient's heart valve. The delivery system includes a sheath assembly, a multi-lumen shaft, and a guide wire for placing the apparatus endovascularly within a patient and a user control allowing manipulation of the aortic prosthesis. The apparatus includes an anchor and a replacement valve. The anchor and the replacement valve are adapted for percutaneous delivery and deployment within a patient's heart valve. In preferred embodiments, the anchor includes a leaflet engagement element and/or a seal inverting element situated on its proximal end. The leaflet engagement element is adapted for engaging the native leaflets of the patient's heart, or more preferably the proximal edge and/or the commissural attachments of the native leaflets. The leaflet engagement element need not extend all the way into the pocket or the distal end of the native leaflet. Preferred embodiments of the apparatus herein are depicted inFIGS. 1-14, which are discussed in more detail below.

FIGS. 1A and 1Billustrate one embodiment of a delivery system and the apparatus of the present invention.

As illustrated byFIG. 1A, apparatus10may be collapsed for delivery within a delivery system100. Delivery system100includes a guidewire102, a nosecone104, anchor actuation elements106(in this case fingers) coupled to a multi-lumen shaft108, an external sheath110having a proximal handle111, and a control handle120. Delivery system100further comprises distal region control elements (not shown), comprised of or actuated by control wires112, which pass through one or more lumens of shaft108and are reversibly coupled to posts32of anchor30for manipulating a distal region of apparatus10. Thus, the distal region control elements may function as a distal actuation element.

The delivery system also comprises proximal region control elements comprised of or actuated by control wires112that pass through one or more lumens of shaft108and anchor actuation elements106to reversibly couple the control tubes to a proximal region of anchor30. The control wires may comprise, for example, strands of suture, or metal or polymer wires. Control handle120is coupled to multi-lumen shaft108. In some embodiments, these fingers and wires may be referred to as proximal actuation elements. A knob122disposed in slot123is coupled to the distal region control wires for controlling movement of the distal region of apparatus10. Likewise, a knob124disposed in slot125is coupled to proximal region control wires112for control of the proximal region of apparatus10. Handle120may also have a knob126for, e.g., decoupling the proximal and/or distal region control wires from apparatus10, or for performing other control functions.

As illustrated byFIG. 1B, apparatus10comprises an anchor30and a replacement valve20. Anchor30preferably comprises a braid. Such braid can have closed ends at either or both of its ends but preferably at least in its proximal end. Replacement valve20is preferably coupled to the anchor at posts32attached at distal region of the anchor. Post32therefore, may function as valve support and may be adapted to support the replacement valve within the anchor. In the embodiment shown, there are three posts, corresponding to the valve's three commissure attachments. The posts can be attached to braid portion of anchor30. The posts can be attached to the braid's distal end, as shown inFIG. 2, central region, or proximal end. Replacement valve20can be composed of a metal, a synthetic material and/or may be derived from animal tissue. Replacement valve20is preferably configured to be secured within anchor30.

In preferred embodiments, anchor30is collapsible and/or expandable and is formed from material such as Nitinol™, cobalt-chromium steel or stainless steel wire. More preferably, an anchor30is self-collapsing and/or self-expanding and is made out of shape memory material, such as Nitinol™. An anchor composed of shape memory material may self-expand to or toward its “at-rest” configuration. This “at rest” configuration of an anchor can be, for example its expanded configuration, its collapsed configuration, or a partially expanded configuration (between the collapsed configuration and the expanded configuration). In preferred embodiments, an anchor's at-rest configuration is between its collapsed configuration and its expanded configuration. Depending on the “at rest” diameter of the anchor and the diameter of the patient's anatomy at the chosen deployment location, the anchor may or may not self-expand to come into contact with the diameter of the patient's anatomy at that location.

Anchor30may be expanded to a fully deployed configuration from a partial deployed configuration (e.g., self-expanded configuration) by actively foreshortening anchor30during endovascular deployment. Active foreshortening is described in more detail in U.S. patent application Ser. No. 10/746,280, which is incorporated herein by reference in its entirety. During active foreshortening, the distal region of anchor30may be pulled proximally via a proximally directed force applied to posts32via a distal deployment system interface comprised of the distal system control elements. The distal deployment system interface is adapted to expand radially during application of a proximally directed force on the distal end of the anchor when opposed by a distally directed force applied to the proximal end of the anchor.

In some embodiments, actuating foreshortening of the apparatus involves applying a proximally directed force on a deployment system interface at the distal end of the anchor, while maintaining the proximal end of the anchor in the same location. In other embodiments, foreshortening of the apparatus involves applying a distally directed force on proximal end of the anchor (e.g., by applying a distally directed force on the anchor actuation elements).

Anchor actuation elements106(e.g., fingers, tubes, posts, and control wires connecting to posts) are preferably adapted to expand radially as the anchor expands radially and to contract radially as the anchor contracts radially. Furthermore, proximally or distally directed forces by the anchor actuation elements on one end of the anchor do not diametrically constrain the opposite end of the anchor. In addition, when a proximally or distally directed force is applied on the anchor by the anchor actuation elements, it is preferably applied without passing any portion of a deployment system through a center opening of the replacement valve. This arrangement enables the replacement valve to operate during deployment and before removal of the deployment system.

The distal deployment system interface may include control wires that are controlled, e.g., by control knob122of control handle120. Similarly, the proximal regions of anchor30may be pushed distally via a proximal deployment system interface at the proximal end of the anchor. The proximal deployment system interface is adapted to permit deployment system to apply a distally directed force to the proximal end of anchor30through, e.g., fingers, which are controlled by, e.g., control knob124of control handle120. The proximal deployment system interface may be further adapted to expand radially during application of a distally directed force on the proximal end of the anchor. Preferably, the proximal deployment system interface is adapted to permit deployment system to apply a distally directed force on the proximal end of the anchor system through a plurality of deployment system fingers or tubes160. Such expansion optionally may be assisted via inflation of a balloon catheter (not shown) reversibly disposed within apparatus10, as described in U.S. patent application Ser. No. 10/746,280.

Once anchor30is fully deployed, posts32and buckles34of anchor30may be used to lock and maintain the anchor in the deployed configuration. In one embodiment, the control wires attached to posts32are threaded through buckles34so that the proximally directed force exerted on posts32by the control wires during deployment pulls the proximal locking end of posts32toward and through buckles34. Such lock optionally may be selectively reversible to allow for repositioning and/or retrieval of apparatus10during or post-deployment. Apparatus10may be repositioned or retrieved from the patient until the two-part locking mechanism of posts32and buckles34of anchor30have been actuated. When the lock is selectively reversible, the apparatus may be repositioned and/or retrieved as desired, e.g., even after actuation of the two-part locking mechanism. Once again, further details of this and other anchor locking structures may be found in U.S. patent application Ser. No. 10/746,280. Locking mechanisms used herein may also include a plurality of levels of locking wherein each level of locking results in a different amount of expansion. For example, the proximal end of the post can have multiple configurations for locking within the buckle wherein each configuration results in a different amount of anchor expansion.FIG. 2illustrates a braided anchor ofFIG. 1in the collapsed delivery configuration with locking elements separated.

FIG. 3provides a detail view of a front side region of anchor braid30with closed end turns Tu. Anchor braid30includes various cells, some having an end turn (Tu). End turns can serve various functions. For example, end turns can be configured to reduce the sheathing force, to reduce stress within the braid during delivery and deployment, to prevent distal migration during expansion of the anchor, and/or to positively register the anchor against the native valve during deployment. In preferred embodiments, an end turn feature functions to prevent distal migration and to register the anchor by engaging the native leaflets. In preferred embodiments, the proximal end of an anchor comprises embodiments (Tu).

FIGS. 4A-4Nprovide multiple examples of edge cells having end turn feature. The end turn features disclosed and others known in the art may be used as leaflet engagement elements to engage the native heart leaflets with the anchor. The leaflet engagement elements are preferably integral with the anchor, or more preferably part of a braided anchor. The end turn features can occur at the proximal end, the distal end, or both proximal and distal ends of the anchor.

For example,FIG. 4Aillustrates a detail view of a standard end turn Tu in an anchor braid resulting in a braid with substantially uniform cell size and shape.

FIG. 4Billustrates a turn that has been elongated to lengthen the distance over which forces concentrated in the turn may be distributed, resulting in an anchor braid having edge cells that are longer along the anchor axis than the other cells defined by the braid. This elongated turn feature may be formed by routing the wire of braid about outer posts and then heat setting the wire.

FIG. 4Cillustrates an alternative anchor edge cell configuration, wherein the tip of the elongated wire turn may be bent out of a cylindrical shape defined by the braid of anchor braid30. This may be achieved, for example, via a combination of routing of wire W within a fixture and then heat setting. Such a turn Tu in the anchor edge cells inFIG. 4Cmay reduce stress in some configurations without increasing height, and may also provide a lip for engaging the patient's native valve leaflets to facilitate proper positioning of apparatus10during deployment.

InFIG. 4D, a W-shaped turn feature has been formed at the wire turn, e.g., by routing the wire of anchor braid30about a central inner post and two flanking outer posts. As with the elongated braid cells ofFIGS. 4B and 4C, the W-shape may better distribute stress about turn Tu.

The anchor edge cell configuration inFIG. 4Eincludes a loop formed in braid30at the turn, which may be formed by looping wire W around an inner or outer post.

FIG. 4Fprovides another alternative anchor edge cell configuration having a figure-eight shape. Such a shape may be formed, for example, by wrapping wire W about an inner post and an aligned outer post in a figure-eight fashion, and then heat setting the wire in the resultant shape.

InFIG. 4G, the edge cells of braid30include a heart-shaped configuration, which may be formed by wrapping the wire about an aligned inner and outer post in the desired manner.

InFIG. 4H, the edge cells of braid30have an asymmetric loop at turn Tu. The asymmetric loop will affect twisting of braid30during expansion and collapse of the braid, in addition to affecting stress concentration.

InFIG. 4I, the anchor edge cells have a double-looped turn configuration, e.g. via wrapping about two adjacent inner or outer posts. Additional loops may also be employed.

The double loop turn feature may be formed with a smooth transition between the loops, as inFIG. 4I, or may be heat set with a more discontinuous shape, as inFIG. 4J.

FIG. 4Killustrates that the edge cells of braid30may have multiple different configurations about the anchor's circumference. For example, the anchor edge cells shown inFIG. 4Khave extended length cells as inFIG. 4Bdisposed adjacent to standard size edge cells, as inFIG. 4A.

The anchor edge cells ofFIG. 4Lhave an extended turn configuration having an extended loop.

The anchor edge cells shown inFIG. 4Mhave an alternative extended configuration with a specified heat set profile.

InFIG. 4N, some or all anchor edge cells are interwoven. When interwoven, one or more edge cells may be shorter or longer than an adjacent edge cell. This permits one or more edge cells to extend into one or more leaflet pocket(s). For example, inFIG. 4Nthe middle Tu may be taller than the two adjacent edge cells thus permitting the edge cell to be situated within a leaflet pocket.

In any of the embodiments herein, edge cells may be wrapped using wire, string, or sutures, at a location where the wire overlaps after an end turn as is illustrated inFIG. 4O. This tied-end turn feature prevents cells from interlocking with each other during deployment.

The anchor and any of its features may be heat set at different configurations. For example, the anchor may be heat set ay its “at rest” configuration such that upon unsheathing it expands radially. The end turn features/leaflet engagement elements may be heat set at a different “at rest” configuration than the rest of the anchor. In preferred embodiment, end turn features are heat set to “flower” and then “evert” upon unsheathing.

The end turn features ofFIG. 4are provided only for the sake of illustration and should in no way be construed as limiting. Additional turn features within the scope of the present invention will apparent to those of skill in the art in view ofFIG. 4. Furthermore, combinations of any such end turn features may be provided to achieve the desired characteristics of anchor30.

Referring now toFIGS. 5A-E, additional configurations for reducing stress concentration and/or circumferential stiffness of an anchor braid and/or leaflet engagement elements are illustrated. Such configurations can be used independently or in conjunction with other configurations disclosed herein. Such configurations are preferably used at the anchor's edges to locally reduce the cross-sectional area of substantially all cells or all cells in the anchor braid's edge (e.g., proximal and/or distal). As seen inFIGS. 5A and 5B, turns Tu in wire W typically may have a substantially continuous (e.g., round) cross-sectional profile. As seen inFIG. 5C, modifying the edge cell configuration by locally reducing the thickness or cross-sectional area of wire W at turn(s) Tu will reduce stress concentration within the wire at the turns and facilitate collapse and/or expansion of anchor braid30from the delivery to the deployed configurations. Furthermore, it is expected that such localized reduction in thickness or cross-sectional area will reduce a risk of kinking, fatigue or other failure at turns Tu.

In any of the embodiments herein, localized reduction of an anchor wire may be achieved via a localized etching and/or electropolishing process. Alternatively or additionally, localized grinding of the turns may be utilized. Additional processing techniques will be apparent to those of skill in the art. As seen inFIGS. 5D-5E, wire W may, for example, comprise an oval or rectangular cross-sectional profile, respectively, after localized reduction. The wire alternatively may comprise a round profile of reduced cross-sectional area (not shown). Additional profiles will be apparent. Localized reduction can take place at any time (e.g., before or after a braid is woven). Preferably, localized reduction occurs after weaving. However, in some embodiments, a wire of a given length may be etched or ground at preset segments and subsequently woven.

With reference now toFIGS. 6A-F, a method of endovascularly replacing a patient's diseased aortic valve is provided. The method involves endovascularly delivering an anchor/valve apparatus and properly positioning such apparatus via positive registration with the patient's native valve leaflets. Registration with the native valve leaflet preferably occurs using the leaflet engagement elements.

InFIG. 6A, modified delivery system100′ delivers apparatus10to diseased aortic valve AV within sheath110. Apparatus10is delivered in a collapsed delivery configuration.

As seen inFIGS. 6B and 6C, apparatus10is deployed from lumen112of sheath110, for example, under fluoroscopic guidance. Sheath110includes at its distal end leaflet engagement elements120. Upon deployment, anchor30of apparatus10dynamically self-expands to a partially deployed configuration. This causes tubes60to also dynamically expand, as well as membrane filter (or braid)61A and leaflet engagement elements120. As when deployed via delivery system100, deployment of apparatus10via delivery system100′ is fully reversible until locks40have been actuated.

Thus, delivery system100′ comprises leaflet engagement element120, which preferably self-expands along with anchor30. In preferred embodiments, the distal end of leaflet engagement elements120expands a greater radial distance than anchor30. Moreover, engagement elements120may be disposed between tubes60of delivery system100′ and lip region32of anchor30. However, leaflet engagement elements120may also be disposed on the proximal end of an anchor (as is illustrated inFIG. 7). Leaflet engagement elements120releasably engage the anchor. As seen inFIG. 6C, the leaflet engagement elements120are initially deployed proximal of the patient's native valve leaflets L. Apparatus10and element120then may be advanced/dynamically repositioned until engagement element positively registers against the leaflets, thereby ensuring proper positioning of apparatus10. The leaflet engagement element engages with the proximal edges of the native valve leaflets and/or the commissural attachments. The leaflet engagement element need not extend all the way to the distal edge of the native leaflets (the leaflet pockets). In preferred embodiments, a leaflet engagement element length is less than about 20 mm, more preferably less than about 15 mm, or more preferably less than about 10 mm. Once leaflet engagement element120is registered against the native valve leaflets and/or commissural attachments, apparatus10deploys substantially distal to the coronary ostia of the heart.

In any of the embodiments herein, delivery system100′ can include filter structure61A (e.g., filter membrane or braid) as part of push tubes60to act as an embolic protection element. Emboli can be generated during manipulation and placement of anchor from either diseased native leaflet or surrounding aortic tissue and can cause blockage. Arrows61B inFIG. 6Cshow blood flow through filter structure61A where blood is allowed to flow but emboli is trapped in the delivery system and removed with it at the end of the procedure.

Active foreshortening may be imposed upon anchor30while element120is disposed proximal of the leaflets, as is illustrated inFIG. 6D. Active foreshortening can be accomplished by actuating distal anchor actuation elements (e.g., wires50) and/or proximal anchor actuation elements (e.g., tubes60). Upon positive registration of element120against leaflets L, element120precludes further distal migration of apparatus10during additional foreshortening, thereby reducing a risk of improperly positioning the apparatus.FIG. 6Edetails engagement of element120against the native leaflets.

As seen inFIG. 6F, once apparatus10is fully deployed, anchor30may be locked (reversibly or irreversibly). Subsequently, structure61A leaflet engagement, elements120, wires50and/or tubes60may be decoupled from the apparatus, and delivery system100′ may be removed from the patient, thereby completing the procedure.

FIG. 7illustrates an alternative embodiment of the apparatus ofFIGS. 6A-Fdescribed above, wherein leaflet engagement elements120are coupled to anchor30of apparatus10′ rather than to delivery system100. In the embodiment illustrated inFIG. 7, leaflet engagement elements120remain implanted near the patient's native heart valve after the deployment of apparatus10′ and removal of delivery system100. Leaflets L may be sandwiched between the proximal region of anchor30and leaflet engagement element120in the fully deployed configuration. In this manner, element120positively registers apparatus10′ relative to the leaflets L and precludes distal migration of the apparatus over time.

FIGS. 8A-8Cillustrate another embodiment for endovascularly delivering an apparatus of the present invention. InFIG. 8A, a catheter600is delivered percutaneously in a retrograde fashion to the aortic valve. The catheter passes through the native aortic valve before an operator actuates the unseathing of the anchor/valve apparatus. As the sheathing catheter is pulled proximally out of the native valve, anchor30and replacement valve20become unsheathed. Immediately the portion of the unsheathed anchor30dynamically self-expands to its “at rest” position, and replacement valve20within the anchor regains an uncollapsed structure, allowing it to begin to function. In preferred embodiments in its “at rest” position, anchor30presses against the native leaflets limiting blood from flowing in between the anchor and leaflet. Also, in preferred embodiments, anchor30portions relatively adjacent to the valve is externally covered by a seal60, more preferably the entire exterior contour of anchor30excluding the leaflet engagement elements is externally covered by a seal, or more preferably the entire contour of anchor30including the external face of the leaflet engagement elements is externally covered by a seal. A seal can be composed of any material that prevents or limits the flow of blood through the anchor. In preferred embodiments, a seal is composed of a thin, elastic polymer or any other type of fabric. The seal can be attached by any means known in the art to the anchor and, in some embodiments, to the distal end of the valve. In preferred embodiments, a seal is attached to the anchor by suturing.

InFIG. 8B, as the catheter is further pulled proximally, the proximal end of anchor30and fingers50are unsheathed. In this embodiment, it is possible to visualize that the seal covers the entire contour of the anchor including the external face of the leaflet engagement element70. As soon as the proximal end of the anchor is exposed, it also dynamically expands. Furthermore, when fingers50become exposed, replacement valve20begins to function permitting blood to flow through replacement valve20, between fingers50, and around the catheter600. This also permits blood to flow into the coronary ostias. In other embodiments where the seal does not cover the proximal end of the anchor, the replacement valve can begin to function as soon as the unsealed portion of the anchor is unsheathed. This causes the leaflet engagement elements70to radially expand to their heat set position and engage with the native heart leaflets.

Next,FIG. 8C, as the apparatus is actively foreshortened using proximal (e.g., fingers) and/or distal actuators (e.g., wires50), the leaflet engagement elements positively register with the native valve leaflets. Foreshortening can cause seal60to bunch up and create pleats. These pleats can then fill pockets thereby improving the paravalvular seal. In preferred embodiments, wherein the leaflet engagement elements are covered with a seal, at least a portion of the seal is also positioned between the native valve leaflets and the aortic wall. Once the anchor is fully compressed within the aortic valve, the anchor is locked, the fingers and post mandrels are disengaged, and the seal is adapted to further limit blood flow around the replacement valve. The catheter is subsequently withdrawn, leaving behind valve20, seal60and anchor70. When ftilly deployed, the anchor is substantially distal to the coronary ostia of the patient such that it will not interfere with blood flow through the ostia.

FIGS. 9A-9Billustrate an embodiment wherein only a distal portion anchor30is covered by seal60and wherein anchor30is only partially deployed since the blood can escape through the proximal end of the anchor braid. As anchor30in this embodiment is unsheathed, it presses against the native valve leaflets. At this point replacement valve20is functional even though anchor30is not fully deployed since blood can escape through the proximal end of the anchor braid. This allows blood to flow through replacement valve20and out of holes in the distal end of anchor30during systole (FIG. 9A) while preventing backflow during diastole (FIG. 9B).

FIGS. 10A-10Billustrate a similar embodiment wherein seal60around anchor30surrounds the entire contour of anchor30. In this embodiment, valve20does not become functional until both anchor30and a portion of fingers50are unsheathed. As soon as a portion of fingers50is unsheathed, replacement valve20is fully functional. This allows blood to flow through replacement valve20and anchor30, out of fingers50, and around catheter60into the aorta and coronary ostias during systole. Similarly, during diastole, replacement valve20closes preventing blood backflow from entering the chamber.

In any of the embodiments herein the anchor is preferably a self-expanding anchor braid. Anchor braid of the present invention can be made from one or more wires, more preferably 2-20 wires, more preferably 3-15 wires, or more preferably 4-10 wires. Moreover, the density of the braid can be modified by various forms of weave used.

FIGS. 11A-11Dillustrate various anchor braid embodiments contemplated by the present invention.

FIG. 11Aillustrates two groups of cells or two braids interwoven in the center. The top group of cells forms a more open weave than the bottom group of cells, which forms a denser weave.

FIG. 11Billustrates another embodiment of an anchor braid having three groups of cells. The top and bottom (proximal and distal) edges of the anchor braid have denser cells than the central portion of the anchor. Also, the edges of the anchor are woven from a thinner filament than the central portion.

In another embodiment illustrated byFIG. 11C, all three sections of an anchor valve are woven by more than one wire. The wires of each section are made of a different material and/or thickness. Wires at the sectional boundaries may or may not interconnect with wires from a different section. Each of the sections of the braid anchor may be composed of a different number of wires.

FIG. 11Dillustrates another embodiment of a braided anchor having three sections. In this embodiment, all sections are composed of a single wire. The proximal and distal sections/edges of the braided anchor have the same pitch. The central region of the braided anchor has a different pitch than the edge sections.

FIGS. 12A-12Eillustrate side views of braided anchor having more than one braid pitch. Varying pitch within the anchor allows localized variations in foreshortening across the anchor, as greater foreshortening is achieved by higher pitch of the braid. Moreover, the localized foreshortening features allow for the design of a braid which incorporates various diameters depending upon the amount of foreshortening. (The greater the foreshortening, the greater the diameter increase upon deployment.)

FIG. 12A, is a side view representation of the braided anchor ofFIG. 11D. On the left side of the figure, the expanded anchor is illustrated having a denser weave (shorter pitch) at the distal and proximal ends; hence the dots are located closer to each other. The middle section of the anchor is composed of a looser weave that is generated by a higher pitch braid and is represented by dots that are farther away from each other. On the right side of the figure, the braided anchor is foreshortened and the dots are collapsed closer to each other. In this case, the central portion of the anchor foreshortened more than the proximal and distal edges.

FIG. 12Billustrates a side view of a foreshortened braided anchor that is created by low pitch at the edges and high pitch in the middle.

FIG. 12Cillustrates a side view of a foreshortened braided anchor that is created by high pitch edges and low pitch middle section.

FIG. 12Dillustrates a side view of a foreshortened braided anchor that includes a sealing feature or space filling feature at both ends. This type of anchor can be created by a high pitch braid at edges, low pitch braid in the middle and heat setting the edges to curl upon unsheathing. These end features can be useful in facilitating anchoring by functioning as a locator and/or sealing. In preferred embodiment the curled ends of the anchor inFIG. 12Dcan be used as leaflet engagement elements.

FIG. 12Eillustrates a side view of a foreshortened braided anchor that is associated with an everting valve or locational features. In preferred embodiments, the middle section of the anchor may be composed of thicker wire(s) than edge section(s). The everting feature at the proximal end can function as a leaflet engagement element as disclosed herein.

FIGS. 13A-13Eillustrate an example of the process of deploying an anchor, such as the one illustrated inFIG. 12Babove.

FIG. 13Aillustrates a braided anchor30in its expanded or elongated configuration. The anchor is composed of three sections. The distal and proximal sections of the anchor are made of a fine weave, low pitch braid and the middle section of the anchor is made of a thicker thread and higher pitch braid. The distal and proximal section are preferably heat set to roll upon unsheathing, though some rolling may occur simply from active for shortening of the fine weave braid. In preferred embodiments, the filaments of the fine weave braid are less than 0.01 cm, or more preferably less than 0.005 cm in thickness. On the other hand, thicker filaments of the middle section are preferably 0.01 cm or greater in thickness or more preferably 0.015 cm or greater in thickness. Posts32are coupled to the middle section of the anchor. For deployment, tubes (or fingers)106are coupled to the anchor's middle section.

FIG. 13Billustrates an anchor during the process of deployment after the anchor is unsheathed. The anchor is pushed distally by tubes and pulled proximally by wires and begins foreshortening. In some embodiment the distal section rolls up and can act as a locator, assisting the operator in locating the aortic valve, or as a seal preventing leakage. In some embodiments, the proximal section may roll down and be used as a leaflet engagement element to prevent distal migration or as a proximal seal.

InFIG. 13C, the device may be configured such that the middle section of the valve may form an hour glass shape or a round shape. The tubes may subsequently be removed as described before.

FIG. 13Dis another illustration of the braided anchor in its elongated configuration.

FIG. 13Eis another illustration of the braided anchor in its foreshortened configuration.

FIGS. 14A-14Cillustrate the process of forming a pleated seal around a replacement valve to prevent leakage.FIG. 14Aillustrates a fabric seal380prior to deployment and foreshortening of the anchor/valve apparatus. InFIG. 14A, the fabric seal380extends from the distal end of valve20proximally over anchor30during delivery. During deployment, as illustrated inFIG. 14B, anchor30foreshortens and the fabric seal380bunches up to create fabric flaps and pockets that extend into spaces formed by the native valve leaflets382. The bunched up fabric or pleats occur, in particular, when the pockets are filled with blood in response to backflow blood pressure. The pleating can create a seal around the replacement valve.FIG. 14Cillustrates anchor30, surrounded by fabric seal380in between native valve leaflets382. In preferred embodiments, at least a portion of a seal is captured between the leaflets and the wall of the heart when the anchor is fully deployed.

FIGS. 15A-Hshow another embodiment of a replacement heart valve apparatus in accordance with the present invention. Apparatus450comprises replacement valve460(seeFIGS. 17B and 18C) disposed within and coupled to anchor470. Replacement valve460is preferably biologic, e.g. porcine, but alternatively may be synthetic. Anchor470preferably is fabricated from self-expanding materials, such as a stainless steel wire mesh or a nickel-titanium alloy (“Nitinol”), and comprises lip region472, skirt region474, and body regions476a,476band476c. Replacement valve460preferably is coupled to skirt region474, but alternatively may be coupled to other regions of the anchor. As described hereinbelow, lip region472and skirt region474are configured to expand and engage/capture a patient's native valve leaflets, thereby providing positive registration, reducing paravalvular regurgitation, reducing device migration, etc.

As seen inFIG. 15A, apparatus450is collapsible to a delivery configuration, wherein the apparatus may be delivered via delivery system410. Delivery system410comprises sheath420having lumen422, as well as wires424aand424bseen inFIGS. 15D-15G. Wires424aare configured to expand skirt region474of anchor470, as well as replacement valve460coupled thereto, while wires424bare configured to expand lip region472.

As seen inFIG. 15B, apparatus450may be delivered and deployed from lumen422of catheter420while the apparatus is disposed in the collapsed delivery configuration. As seen inFIGS. 15B-15D, catheter420is retracted relative to apparatus450, which causes anchor470to dynamically self-expand to a partially deployed configuration. Wires424aare then retracted to expand skirt region474, as seen inFIGS. 15E and 15F. Preferably, such expansion may be maintained via locking features described hereinafter.

InFIG. 15G, wires424bare retracted to expand lip region472and fully deploy apparatus450. As with skirt region474, expansion of lip region472preferably may be maintained via locking features. After both lip region472and skirt region474have been expanded, wires424may be removed from apparatus450, thereby separating delivery system410from the apparatus. Delivery system410then may be removed, as seen inFIG. 15H.

As will be apparent to those of skill in the art, lip region472optionally may be expanded prior to expansion of skirt region474. As yet another alternative, lip region472and skirt region474optionally may be expanded simultaneously, in parallel, in a step-wise fashion or sequentially. Advantageously, delivery of apparatus450is fully reversible until lip region472or skirt region474has been locked in the expanded configuration.

With reference now toFIGS. 16A-E, individual cells of anchor470of apparatus450are described to detail deployment and expansion of the apparatus. InFIG. 16A, individual cells of lip region472, skirt region474and body regions476a,476band476care shown in the collapsed delivery configuration, as they would appear while disposed within lumen422of sheath420of delivery system410ofFIG. 15. A portion of the cells forming body regions476, for example, every ‘nth’ row of cells, comprises locking features.

Body region476acomprises male interlocking element482of lip lock480, while body region476bcomprises female interlocking element484of lip lock480. Male element482comprises eyelet483. Wire424bpasses from female interlocking element484through eyelet483and back through female interlocking element484, such that there is a double strand of wire424bthat passes through lumen422of catheter420for manipulation by a medical practitioner external to the patient. Body region476bfurther comprises male interlocking element492of skirt lock490, while body region476ccomprises female interlocking element494of the skirt lock. Wire424apasses from female interlocking element494through eyelet493of male interlocking element492, and back through female interlocking element494. Lip lock480is configured to maintain expansion of lip region472, while skirt lock490is configured to maintain expansion of skirt region474.

InFIG. 16B, anchor470is shown in the partially deployed configuration, e.g., after deployment from lumen422of sheath420. Body regions476, as well as lip region472and skirt region474, self-expand to the partially deployed configuration. Full deployment is then achieved by retracting wires424relative to anchor470, and expanding lip region472and skirt region474outward, as seen inFIGS. 16C and 16D. As seen inFIG. 16E, expansion continues until the male elements engage the female interlocking elements of lip lock480and skirt lock490, thereby maintaining such expansion (lip lock480shown inFIG. 16E). Advantageously, deployment of apparatus450is fully reversible until lip lock480and/or skirt lock490has been actuated.

With reference toFIGS. 17A-B, isometric views, partially in section, further illustrate apparatus450in the fully deployed and expanded configuration.FIG. 17Aillustrates the wireframe structure of anchor470, whileFIG. 17Billustrates an embodiment of anchor470covered in a biocompatible material B. Placement of replacement valve460within apparatus450may be seen inFIG. 17B. The patient's native valve is captured between lip region472and skirt region474of anchor470in the frilly deployed configuration (seeFIG. 18B).

Referring toFIGS. 18A-C, in conjunction withFIGS. 15 and 16, a method for endovascularly replacing a patient's diseased aortic valve with apparatus450is described. Delivery system410, having apparatus450disposed therein, is endovascularly advanced, preferably in a retrograde fashion, through a patient's aorta A to the patient's diseased aortic valve AV. Sheath420is positioned such that its distal end is disposed within left ventricle LV of the patient's heart H. As described with respect toFIG. 15, apparatus450is deployed from lumen422of sheath420, for example, under fluoroscopic guidance, such that skirt section474is disposed within left ventricle LV, body section476bis disposed across the patient's native valve leaflets L, and lip section472is disposed within the patient's aorta A. Advantageously, apparatus450may be dynamically repositioned to obtain proper alignment with the anatomical landmarks. Furthermore, apparatus450may be retracted within lumen422of sheath420via wires424, even after anchor470has dynamically expanded to the partially deployed configuration, for example, to abort the procedure or to reposition sheath420.

Once properly positioned, wires424aare retracted to expand skirt region474of anchor470within left ventricle LV. Skirt region474is locked in the expanded configuration via skirt lock490, as previously described with respect toFIG. 16. InFIG. 18A, skirt region474is maneuvered such that it engages the patient's valve annulus An and/or native valve leaflets L, thereby providing positive registration of apparatus450relative to the anatomical landmarks.

Wires424bare then actuated external to the patient in order to expand lip region472, as previously described inFIG. 15. Lip region472is locked in the expanded configuration via lip lock480. Advantageously, deployment of apparatus450is fully reversible until lip lock480and/or skirt lock490has been actuated. Wires424are pulled from eyelets483and493, and delivery system410is removed from the patient. As will be apparent, the order of expansion of lip region472and skirt region474may be reversed, concurrent, etc.

As seen inFIG. 18B, lip region472engages the patient's native valve leaflets L, thereby providing additional positive registration and reducing a risk of lip region472blocking the patient's coronary ostia0.FIG. 18Cillustrates the same in cross-sectional view, while also showing the position of replacement valve460. The patient's native leaflets are engaged and/or captured between lip region472and skirt region474. Advantageously, lip region472precludes distal migration of apparatus450, while skirt region474precludes proximal migration. It is expected that lip region472and skirt region474also will reduce paravalvular regurgitation.

With reference toFIGS. 19-21, a first embodiment of two-piece apparatus of the present invention adapted for percutaneous replacement of a patient's heart valve is described. As seen inFIG. 21, apparatus510comprises a two-piece device having custom-designed expandable anchor piece550ofFIG. 19and expandable replacement valve piece600ofFIG. 20. Both anchor piece550and valve piece600have reduced delivery configurations and expanded deployed configurations. Both may be either balloon expandable (e.g. fabricated from a stainless steel) or self-expanding (e.g. fabricated from a nickel-titanium alloy (“Nitinol”) or from a wire mesh) from the delivery to the deployed configurations.

When replacing a patient's aortic valve, apparatus510preferably may be delivered through the patient's aorta without requiring a transseptal approach, thereby reducing patient trauma, complications and recovery time. Furthermore, apparatus510enables dynamic repositioning of anchor piece550during delivery and facilitates positive registration of apparatus510relative to the native position of the patient's valve, thereby reducing a risk of device migration and reducing a risk of blocking or impeding flow to the patient's coronary ostia. Furthermore, the expanded deployed configuration of apparatus510, as seen inFIG. 21D, is adapted to reduce paravalvular regurgitation, as well as to facilitate proper seating of valve piece600within anchor piece550.

As seen inFIG. 19, anchor piece550preferably comprises three sections. Lip section560is adapted to engage the patient's native valve leaflets to provide positive registration and ensure accurate placement of the anchor relative to the patient's valve annulus during deployment, while allowing for dynamic repositioning of the anchor during deployment. Lip section560also maintains proper positioning of composite anchor/valve apparatus510post-deployment to preclude distal migration. Lip section560optionally may be covered or coated with biocompatible film B (seeFIG. 21) to ensure engagement of the native valve leaflets. It is expected that covering lip section560with film B especially would be indicated when the native leaflets are stenosed and/or fused together

Groove section570of anchor piece550is adapted to engage an expandable frame portion, described hereinbelow, of valve piece600to couple anchor piece550to valve piece600. As compared to previously known apparatus, groove section570comprises additional material and reduced openings or gaps G, which is expected to reduce tissue protrusion through the gaps upon deployment, thereby facilitating proper seating of the valve within the anchor. Groove section570optionally may be covered or coated with biocompatible film B (seeFIG. 21) to further reduce native valve tissue protrusion through gaps G.

Finally, skirt section580of anchor piece550maintains proper positioning of composite anchor/valve apparatus510post-deployment by precluding proximal migration. When replacing a patient's aortic valve, skirt section580is deployed within the patient's left ventricle. As with lip section560and groove section570, skirt section580optionally may be covered or coated with biocompatible film B (seeFIG. 21) to reduce paravalvular regurgitation. As will be apparent to those of skill in the art, all, a portion of, or none of anchor piece50may be covered or coated with biocompatible film B.

InFIG. 19A, a portion of anchor piece550has been flattened out to illustrate the basic anchor cell structure, as well as to illustrate techniques for manufacturing anchor piece550. In order to form the entire anchor, anchor550would be bent at the locations indicated inFIG. 19A, and the basic anchor cell structure would be revolved to form a joined 360° structure. Lip section560would be bent back into the page to form a lip that doubles over the groove section, groove section570would be bent out of the page into a ‘C’- or ‘U’-shaped groove, while skirt section580would be bent back into the page.FIG. 19Bshows the anchor portion after bending and in an expanded deployed configuration.

The basic anchor cell structure seen inFIG. 19Ais preferably formed through laser cutting of a flat sheet or of a hollow tube placed on a mandrel. When formed from a flat sheet, the sheet would be cut to the required number of anchor cells, bent to the proper shape, and revolved to form a cylinder. The ends of the cylinder would then be joined together, for example, by heat welding.

If balloon expandable, anchor piece550would be formed from an appropriate material, such as stainless steel, and then crimped onto a balloon delivery catheter in a collapsed delivery configuration. If self-expanding and formed from a shape-memory material, such as a nickel-titanium alloy (“Nitinol”), the anchor piece would be heat-set such that it could be constrained within a sheath in the collapsed delivery configuration, and then would dynamically self-expand to the expanded deployed configuration upon removal of the sheath. Likewise, if anchor piece550were formed from a wire mesh or braid, such as a spring steel braid, the anchor would be constrained within a sheath in the delivery configuration and dynamically expanded to the deployed configuration upon removal of the sheath.

InFIG. 20, valve piece600is described in greater detail.FIG. 20Aillustrates valve piece600in a collapsed delivery configuration, whileFIG. 20Billustrates the valve piece in an expanded deployed configuration. Valve piece600comprises replacement valve610coupled to expandable frame620. Replacement valve610is preferably biologic, although synthetic valves may also be used. Replacement valve610preferably comprises three leaflets611coupled to three posts621of expandable frame620. Expandable frame620is preferably formed from a continuous piece of material and may comprise tips622in the collapsed delivery configuration, which expand to form hoop624in the deployed configuration. Hoop624is adapted to engage groove section570of anchor piece550for coupling anchor piece550to valve piece600. As with anchor piece550, valve piece600may be balloon expandable and coupled to a balloon delivery catheter in the delivery configuration. Alternatively, anchor piece550may be self-expanding, e.g. Nitinol or wire mesh, and constrained within a sheath in the delivery configuration.

Referring again toFIG. 21, a method for deploying valve piece600and coupling it to deployed anchor piece550to form two-piece apparatus510is described. InFIG. 21A, valve piece600is advanced within anchor piece550in an at least partially compressed delivery configuration. InFIG. 21B, tips622of frame620are expanded such that they engage groove section570of anchor piece550. InFIG. 21C, frame620continues to expand and form hoop624. Hoop624flares out from the remainder of valve piece600and acts to properly locate the hoop within groove section570.FIG. 21Dshows valve piece600in a fully deployed configuration, properly seated and friction locked within groove section570to form composite anchor/valve apparatus510.

Anchor piece550and valve piece600of apparatus510preferably are spaced apart and releasably coupled to a single delivery catheter while disposed in their reduced delivery configurations. Spacing the anchor and valve apart reduces a delivery profile of the device, thereby enabling delivery through a patient's aorta without requiring a transseptal approach. With reference toFIG. 22, a first embodiment of single catheter delivery system700for use with apparatus510is described. Delivery system700is adapted for use with a preferred self-expanding embodiment of apparatus510.

Delivery system700comprises delivery catheter710having inner tube720, middle distal tube730, and outer tube740. Inner tube720comprises lumen722adapted for advancement over a standard guide wire, per se known. Middle distal tube730is coaxially disposed about a distal region of inner tube720and is coupled to a distal end724of the inner tube, thereby forming proximally-oriented annular bore732between inner tube720and middle tube730at a distal region of delivery catheter710. Outer tube740is coaxially disposed about inner tube720and extends from a proximal region of the inner tube to a position at least partially coaxially overlapping middle distal tube730. Outer tube740preferably comprises distal step742, wherein lumen743of outer tube740is of increased diameter. Distal step742may overlap middle distal tube730and may also facilitate deployment of valve piece600, as described hereinbelow with respect toFIG. 25.

Proximally-oriented annular bore732between inner tube720and middle distal tube730is adapted to receive skirt section580and groove section570of anchor piece550in the reduced delivery configuration. Annular space744formed at the overlap between middle distal tube730and outer tube740is adapted to receive lip section560of anchor piece550in the reduced delivery configuration. More proximal annular space746between inner tube720and outer tube740may be adapted to receive replacement valve610and expandable frame620of valve piece600in the reduced delivery configuration.

Inner tube720optionally may comprise retainer elements726aand726bto reduce migration of valve piece600. Retainer elements726preferably are fabricated from a radiopaque material, such as platinum-iridium or gold, to facilitate deployment of valve piece600, as well as coupling of the valve piece to anchor piece550. Additional or alternative radiopaque elements may be disposed at other locations about delivery system700or apparatus510, for example, in the vicinity of anchor piece550.

With reference now toFIG. 23, an alternative delivery system for use with apparatus of the present invention is described. Delivery system750comprises two distinct catheters adapted to deliver the anchor and valve pieces, respectively: anchor delivery catheter710′ and valve delivery catheter760. In use, catheters710′ and760may be advanced sequentially to a patient's diseased heart valve for sequential deployment and coupling of anchor piece550to valve piece600to form composite two-piece apparatus510.

Delivery catheter710′ is substantially equivalent to catheter710described hereinabove, except that catheter710′ does not comprise retainer elements726, and annular space746does not receive valve piece600. Rather, valve piece600is received within catheter760in the collapsed delivery configuration. Catheter760comprises inner tube770and outer tube780. Inner tube770comprises lumen772for advancement of catheter760over a guide wire. The inner tube optionally may also comprise retainer elements774aand774b, e.g. radiopaque retainer elements774, to reduce migration of valve piece600. Outer tube780is coaxially disposed about inner tuber770and preferably comprises distal step782to facilitate deployment and coupling of valve piece600to anchor piece550, as described hereinbelow. Valve piece600may be received in annular space776between inner tube770and outer tube780, and more preferably may be received within annular space776between retainer elements774.

Referring now toFIG. 24, another alternative delivery system is described. As discussed previously, either anchor piece550or valve piece600(or portions thereof or both) may be balloon expandable from the delivery configuration to the deployed configuration. Delivery system800is adapted for delivery of an embodiment of apparatus510wherein the valve piece is balloon expandable. Additional delivery systems—both single and multi-catheter —for deployment of alternative combinations of balloon and self-expandable elements of apparatus of the present invention will be apparent to those of skill in the art in view of the illustrative delivery systems provided inFIGS. 22-24.

InFIG. 24, delivery system800comprises delivery catheter710″. Delivery catheter710″ is substantially equivalent to delivery catheter710of delivery system700, except that catheter710″ does not comprise retainer elements726, and annular space746does not receive the valve piece. Additionally, catheter710″ comprises inflatable balloon802coupled to the exterior of outer tube740″, as well as an inflation lumen (not shown) for reversibly delivering an inflation medium from a proximal region of catheter710″ into the interior of inflatable balloon802for expanding the balloon from a delivery configuration to a deployed configuration. Valve piece600may be crimped to the exterior of balloon802in the delivery configuration, then deployed and coupled to anchor piece550in vivo. Delivery catheter710″ preferably comprises radiopaque marker bands804a and804b disposed on either side of balloon802to facilitate proper positioning of valve piece600during deployment of the valve piece, for example, under fluoroscopic guidance.

With reference now toFIG. 25, in conjunction withFIGS. 19-22, an illustrative method of endovascularly replacing a patient's diseased heart valve using apparatus of the present invention is described. InFIG. 25A, a distal region of delivery system700ofFIG. 22has been delivered through a patient's aorta A, e.g., over a guide wire and under fluoroscopic guidance using well-known percutaneous techniques, to a vicinity of diseased aortic valve AV of heart H. Apparatus510ofFIGS. 19-21is disposed in the collapsed delivery configuration within delivery catheter710with groove section570and skirt section580of anchor piece550collapsed within annular bore732, and lip section560of anchor piece550collapsed within annular space744. Valve piece600is disposed in the collapsed delivery configuration between retainer elements726within more proximal annular space746. Separation of anchor piece550and valve piece600of apparatus510along the longitudinal axis of delivery catheter710enables percutaneous aortic delivery of apparatus510without requiring a transseptal approach.

Aortic valve AV comprises native valve leaflets L attached to valve annulus An. Coronary ostia O are disposed just proximal of diseased aortic valve AV. Coronary ostia O connect the patient's coronary arteries to aorta A and are the conduits through which the patient's heart muscle receives oxygenated blood. As such, it is critical that the ostia remain unobstructed post-deployment of apparatus510.

InFIG. 25A, a distal end of delivery catheter710has been delivered across diseased aortic valve AV into the patient's left ventricle LV. As seen inFIG. 25B, outer tube740is then retracted proximally relative to inner tube720and middle distal tube730. Outer tube740no longer coaxially overlaps middle distal tube730, and lip section560of anchor piece550is removed from annular space744. Lip section560self-expands to the deployed configuration. As seen inFIG. 25C, inner tube720and middle tube730(or all of delivery catheter710) are then distally advanced until lip section560engages the patient's native valve leaflets L, thereby providing positive registration of anchor piece550to leaflets L. Registration may be confirmed, for example, via fluoroscopic imaging of radiopaque features coupled to apparatus510or delivery system700and/or via resistance encountered by the medical practitioner distally advancing anchor piece550.

Lip section560may be dynamically repositioned until it properly engages the valve leaflets, thereby ensuring proper positioning of anchor piece550relative to the native coronary ostia O, as well as the valve annulus An, prior to deployment of groove section570and skirt section580. Such multi-step deployment of anchor piece550enables positive registration and dynamic repositioning of the anchor piece. This is in contrast to previously known percutaneous valve replacement apparatus.

As seen inFIG. 25D, once leaflets L have been engaged by lip section560of anchor piece550, inner tube720and middle distal tube730are further distally advanced within left ventricle LV, while outer tube740remains substantially stationary. Lip section560, engaged by leaflets L, precludes further distal advancement/migration of anchor piece550. As such, groove section570and skirt section580are pulled out of proximally-oriented annular bore732between inner tube720and middle distal tube730when the tubes are distally advanced. The groove and skirt sections self-expand to the deployed configuration, as seen inFIG. 25E. Groove section570pushes native valve leaflets L and lip section560against valve annulus An, while skirt section580seals against an interior wall of left ventricle LV, thereby reducing paravalvular regurgitation across aortic valve AV and precluding proximal migration of anchor piece550.

With anchor piece550deployed and native aortic valve AV displaced, valve piece600may be deployed and coupled to the anchor piece to achieve percutaneous aortic valve replacement. Outer tube740is further proximally retracted relative to inner tube720such that valve piece600is partially deployed from annular space746between inner tube720and outer tube740, as seen inFIG. 25F. Expandable frame620coupled to replacement valve610partially self-expands such that tips622partially form hoop624for engagement of groove section570of anchor piece550(seeFIG. 21B). A proximal end of expandable frame620is engaged by distal step742of outer tube740.

Subsequent re-advancement of outer tube740relative to inner tube720causes distal step742to distally advance valve piece600within anchor piece550until tips622of expandable frame620engage groove section570of anchor piece550, as seen inFIG. 25G. As discussed previously, groove section570comprises additional material and reduced openings or gaps G, as compared to previously known apparatus, which is expected to reduce native valve tissue protrusion through the gaps and facilitate engagement of tips622with the groove section. Outer tube740then is proximally retracted again relative to inner tube720, and valve piece600is completely freed from annular space746. Frame620of valve piece600fully expands to form hoop624, as seen inFIG. 25H.

Hoop624friction locks within groove section570of anchor piece550, thereby coupling the anchor piece to the valve piece and forming composite two-piece apparatus510, which provides a percutaneous valve replacement. As seen inFIG. 25I, delivery catheter710may then be removed from the patient, completing the procedure. Blood may freely flow from left ventricle LV through replacement valve610into aorta A. Coronary ostia O are unobstructed, and paravalvular regurgitation is reduced by skirt section580of anchor piece550.

Referring now toFIG. 26, an alternative embodiment of two-piece apparatus510is described comprising an alignment/locking mechanism. Such a mechanism may be provided in order to ensure proper radial alignment of the expandable frame of the valve piece with the groove section of the anchor piece, as well as to ensure proper longitudinal positioning of the frame within the hoop. Additionally, the alignment/locking mechanism may provide a secondary lock to further reduce a risk of the anchor piece and the valve piece becoming separated post-deployment and coupling of the two pieces to achieve percutaneous valve replacement.

InFIG. 26, apparatus510′ comprises valve piece600′ ofFIG. 26Aand anchor piece550′ ofFIG. 26B. Anchor piece550′ and valve piece600′ are substantially the same as anchor piece550and valve piece600described hereinabove, except that anchor piece550′ comprises first portion652of illustrative alignment/locking mechanism650, while valve piece600′ comprises second portion654of the alignment/locking mechanism for coupling to the first portion. First portion652illustratively comprises three guideposts653coupled to skirt section580′ of anchor piece550′ (only one guidepost shown in the partial view ofFIG. 26B), while second portion654comprises three sleeves655coupled to posts621′ of expandable frame620′ of valve piece600′.

When anchor piece550′ is self-expanding and collapsed in the delivery configuration, guideposts653may be deployed with skirt section580′, in which case guideposts653would rotate upward with respect to anchor piece550′ into the deployed configuration ofFIG. 26B. Alternatively, when anchor piece550′ is either balloon or self-expanding and is collapsed in the delivery configuration, guideposts653may be collapsed against groove section570′ of the anchor piece and may be deployed with the groove section. Deploying guideposts653with skirt section580′ has the advantages of reduced delivery profile and ease of manufacturing, but has the disadvantage of significant dynamic motion during deployment. Conversely, deploying guideposts653with groove section570′ has the advantage of minimal dynamic motion during deployment, but has the disadvantage of increased delivery profile. Additional deployment configurations will be apparent to those of skill in the art. As will also be apparent, first portion652of alignment/locking mechanism650may be coupled to alternative sections of anchor piece550′ other than skirt section580′.

Sleeves655of second portion654of alignment/locking mechanism650comprise lumens656sized for coaxial disposal of sleeves655about guideposts653of first portion652. Upon deployment, sleeves655may friction lock to guideposts653to ensure proper radial and longitudinal alignment of anchor piece550′ with valve piece600′, as well as to provide a secondary lock of the anchor piece to the valve piece. The secondary lock enhances the primary friction lock formed by groove section570′ of the anchor piece with hoop624′ of expandable frame620′ of the valve piece.

To facilitate coupling of the anchor piece to the valve piece, suture or thread may pass from optional eyelets651aof guideposts653through lumens656of sleeves655to a proximal end of the delivery catheter (seeFIG. 27). In this manner, second portion654of mechanism650may be urged into alignment with first portion652, and optional suture knots (not shown), e.g. pre-tied suture knots, may be advanced on top of the mechanism post-coupling of the two portions to lock the two portions together. Alternatively, guideposts653may comprise optional one-way valves651bto facilitate coupling of the first portion to the second portion. Specifically, sleeves655may be adapted for coaxial advancement over one-way valves651bin a first direction that couples the sleeves to guideposts653, but not in a reverse direction that would uncouple the sleeves from the guideposts.

Referring now toFIG. 27, an alternative embodiment of apparatus510′ comprising an alternative alignment/locking mechanism is described. Apparatus510″ is illustratively shown in conjunction with delivery system700described hereinabove with respect toFIG. 22. Valve piece600″ is shown partially deployed from outer tube740of catheter710. For the sake of illustration, replacement valve610″ of valve piece600″, as well as inner tube720and middle distal tube730of delivery catheter710, are not shown inFIG. 27.

InFIG. 27, anchor piece550″ of apparatus510″ comprises first portion652′ of alignment/locking mechanism650′, while valve piece600″ comprises second portion654′ of the alternative alignment/locking mechanism. First portion652′ comprises eyelets660coupled to groove section570″ of anchor piece550″. Second portion654′ comprises knotted loops of suture662coupled to tips622″ of expandable frame620″ of valve piece600″. Suture661extends from knotted loops of suture662through eyelets660and out through annular space746between outer tube740and inner tube720(seeFIG. 22) of catheter710to a proximal end of delivery system700. In this manner, a medical practitioner may radially and longitudinally align valve piece600″ with anchor piece550″ by proximally retracting sutures661(as shown by arrows inFIG. 27) while distally advancing distal step742of outer tube740against valve piece600″ until tips622″ of the valve piece engage groove section570″ of anchor piece550″. Proximal retraction of outer tube740then causes expandable frame620″ to further expand and form hoop624″ that friction locks with groove section570″ of anchor piece550″, thereby forming apparatus510″ as described hereinabove with respect to apparatus510. A secondary lock may be achieved by advancing optional suture knots (not shown) to the overlap of eyelets660and knotted loops of suture662. Such optional suture knots preferably are pre-tied.

With reference now toFIG. 28, yet another alternative embodiment of apparatus510′, comprising yet another alternative alignment/locking mechanism650, is described. First portion652″ of alignment/locking mechanism650″ is coupled to anchor piece550′″ of apparatus510′″, while second portion654″ is coupled to valve piece600′″. The first portion comprises male posts670having flared ends671, while the second portion comprises female guides672coupled to tips622′″ of expandable frame620′″ of valve piece600″′.

Female guides672are translatable about male posts670, but are constrained by flared ends671of the male posts. In this manner, anchor piece550′″ and valve piece600′″ remain coupled and in radial alignment with one another at all times—including delivery—but may be longitudinally separated from one another during delivery. This facilitates percutaneous delivery without requiring a transseptal approach, while mitigating a risk of inadvertent deployment of the anchor and valve pieces in an uncoupled configuration. Additional alignment/locking mechanisms will be apparent in view of the mechanisms described with respect toFIGS. 26-28.