Stent designs for prosthetic heart valves

A prosthetic heart valve includes a collapsible and expandable stent, a cuff attached to an annulus section of the stent, and leaflets attached to the cuff between a first location and a second location distal to the first location in a flow direction. The stent may include struts shaped to form a plurality of cells connected to one another in annular rows around the stent. The cuff may have top and bottom edges and may occupy a first group of the cells, such that cells above the top edge are open cells at least partially devoid of the cuff. The cuff may have a landing zone extending at least one-third of a length of the stent in the flow direction between the bottom edge of the cuff and a proximal end of a most proximal cell of the open cells when the stent is in an expanded use condition.

BACKGROUND OF THE INVENTION

The present invention relates to heart valve replacement and, in particular, to collapsible prosthetic heart valves. More particularly, the present invention relates to collapsible prosthetic heart valves having improved stent designs.

Prosthetic heart valves that are collapsible to a relatively small circumferential size can be delivered into a patient less invasively than valves that are not collapsible. For example, a collapsible valve may be delivered into a patient via a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for a more invasive procedure such as full open-chest, open-heart surgery.

Collapsible prosthetic heart valves typically take the form of a valve structure mounted on a stent. There are two types of stents on which the valve structures are ordinarily mounted: a self-expanding stent and a balloon-expandable stent. To place such valves into a delivery apparatus and ultimately into a patient, the valve must first be collapsed or crimped to reduce its circumferential size.

When a collapsed prosthetic valve has reached the desired implant site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and re-expanded to full operating size. For balloon-expandable valves, this generally involves releasing the valve, assuring its proper location, and then expanding a balloon positioned within the valve stent. For self-expanding valves, on the other hand, the stent automatically expands as the sheath covering the valve is withdrawn.

BRIEF SUMMARY OF THE INVENTION

Prosthetic heart valves and methods of expanding a prosthetic heart valve between native leaflets of a native aortic annulus of a patient are disclosed.

A prosthetic heart valve configured to be expanded between native leaflets of a native aortic annulus of a patient may include a collapsible and expandable stent, a cuff attached to the stent, and a plurality of prosthetic valve leaflets attached to the cuff. The stent may have a proximal end, a distal end, an annulus section adjacent the proximal end, and an aortic section adjacent the distal end. The stent may include a plurality of struts shaped to form a plurality of cells connected to one another in a plurality of annular rows around the stent. The stent may define a flow direction from the proximal end toward the distal end. The stent may have a minimum diameter in a direction perpendicular to the flow direction and a length in the flow direction between the proximal and distal ends when the stent is in an expanded use condition, the length being greater than the minimum diameter.

The cuff may be attached to the annulus section of the stent. The cuff may have top and bottom edges and may occupy a first group of the cells, such that the cells above the top edge are open cells at least partially devoid of the cuff. The cuff may have a landing zone extending at least one-third of the length of the stent in the flow direction between the bottom edge of the cuff and a proximal end of a most proximal cell of the open cells when the stent is in the expanded use condition. The prosthetic valve leaflets may be attached to the cuff between a first location and a second location distal to the first location in the flow direction, each of the prosthetic valve leaflets having a free edge.

A prosthetic heart valve configured to be expanded between native leaflets of a native aortic annulus of a patient may include a collapsible and expandable stent, a cuff attached to the stent, and a plurality of prosthetic valve leaflets attached to the cuff. The stent may have a proximal end, a distal end, an annulus section adjacent the proximal end, and an aortic section adjacent the distal end. The stent may include a plurality of struts shaped to form a plurality of cells connected to one another in a plurality of annular rows around the stent. The stent may define a flow direction from the proximal end toward the distal end.

The cuff may be attached to the annulus section of the stent. The cuff may have top and bottom edges and occupying a first group of the cells, such that the cells above the top edge are open cells at least partially devoid of the cuff. The cuff may have a landing zone extending at least 16 mm in the flow direction between the bottom edge of the cuff and a proximal end of a most proximal cell of the open cells when the stent is in an expanded use condition. The plurality of prosthetic valve leaflets may be attached to the cuff between a first location and a second location distal to the first location in the flow direction. Each of the prosthetic valve leaflets may have a free edge.

The landing zone may extend at least 16 mm in the flow direction between the bottom edge of the cuff and the proximal end of the most proximal cell of the open cells when the stent is in an expanded use condition. The entire free edge of each of the prosthetic valve leaflets may be located within a first distance in the flow direction from the distal end of the stent when the prosthetic valve leaflets are in the open position and the stent is in the expanded use condition, the first distance being less than a length of the landing zone in the flow direction.

The cuff may include a proximal portion and a distal portion. The proximal portion may be coupled to a first group of the plurality of struts adjacent the bottom edge and may have a first average thickness in a radial direction perpendicular to the flow direction. The distal portion may be coupled to a second group of the plurality of struts adjacent the top edge and may have a second average thickness in the radial direction, the first average thickness being greater than the second average thickness. Substantially all of the proximal portion of the cuff may be located between the first location and the proximal end of the stent. The cuff may be disposed on a luminal surface of the stent.

The distal portion of the cuff may include a plurality of pockets containing a material that is configured to swell in size when contacted by blood. The proximal portion of the cuff may occupy every cell in a first row of the annular rows of cells. The distal portion of the cuff may occupy every cell in a second row of the annular rows of cells adjacent the first row. The distal portion of the cuff may also occupy a subset of cells in a third row of the annular rows of cells adjacent the second row such that at least some of the open cells are located in the third row.

The proximal portion of the cuff may be initially separate from the distal portion of the cuff and may be coupled to a bottom edge of the distal portion of the cuff at a top edge of the proximal portion of the cuff. The proximal portion of the cuff and the distal portion of the cuff may be made of different materials. The proximal portion of the cuff and the distal portion of the cuff may be joined to one another along a boundary line that extends between adjacent rows of the annular rows of cells. The proximal portion of the cuff and the distal portion of the cuff may be joined to one another along a boundary line that extends in a substantially circular closed curve about a circumference of the stent, the curve lying in a plane generally perpendicular to the flow direction.

A prosthetic heart valve configured to be expanded between native leaflets of a native aortic annulus of a patient may include a collapsible and expandable stent, a cuff attached to the stent, and a plurality of prosthetic valve leaflets attached to the cuff. The stent may have a proximal end, a distal end, an annulus section adjacent the proximal end, and an aortic section adjacent the distal end. The stent may include a plurality of struts shaped to form a plurality of cells connected to one another in a plurality of annular rows around the stent. The stent may define a flow direction from the proximal end toward the distal end. The stent may have a minimum diameter in a direction perpendicular to the flow direction and a length in the flow direction between the proximal and distal ends when the stent is in an expanded use condition, the length being greater than the minimum diameter.

The plurality of prosthetic valve leaflets may be attached to the cuff between a first location and a second location distal to the first location in the flow direction. Each of the prosthetic valve leaflets may have a free edge. The entire free edge of each of the prosthetic valve leaflets may be located at least three-fifths of the length of the stent above the proximal end of the stent when the prosthetic valve leaflets are in an open position and the stent is in an expanded use condition.

A prosthetic heart valve configured to be expanded between native leaflets of a native aortic annulus of a patient may include a collapsible and expandable stent, a cuff attached to the stent, and a plurality of prosthetic valve leaflets attached to the cuff. The stent may have a proximal end, a distal end, an annulus section adjacent the proximal end, and an aortic section adjacent the distal end. The stent may include a plurality of struts shaped to form a plurality of cells connected to one another in a plurality of annular rows around the stent. The stent may define a flow direction from the proximal end toward the distal end.

The plurality of prosthetic valve leaflets may be attached to the cuff between a first location and a second location distal to the first location in the flow direction. Each of the prosthetic valve leaflets may have a free edge. The entire free edge of each of the prosthetic valve leaflets may be located at least about 25 mm above the proximal end of the stent when the prosthetic valve leaflets are in an open position and the stent is in an expanded use condition.

The entire free edge of each of the prosthetic valve leaflets may be located at least about 25 mm above the proximal end of the stent when the prosthetic valve leaflets are in the open position and the stent is in the expanded use condition. The entire free edge of each of the prosthetic valve leaflets may be located between about 25 mm and about 40 mm above the proximal end of the stent when the prosthetic valve leaflets are in the open position and the stent is in the expanded use condition. The stent may have a length between the distal end and the proximal end in the flow direction of no more than 50 mm in the expanded use condition. The stent may have a length between the distal end and the proximal end in the flow direction of between about 30 mm and about 50 mm in the expanded use condition.

The aortic section may have an expanded diameter greater than an expanded diameter of the annulus section. The annulus section of the stent may include three of the annular rows of cells and the aortic section of the stent may include one of the annular rows of cells. The rows of cells in the annulus section together may have a greater combined length in the flow direction than the row of cells in the aortic section when the stent is in the expanded use condition. When the prosthetic heart valve is expanded between the native leaflets of the native aortic annulus such that the proximal end of the stent is located below a proximal end of the native aortic annulus, and the prosthetic valve leaflets are in an open position, the entire free edge of each of the prosthetic valve leaflets may be located above a free edge of each of the native leaflets.

When the prosthetic heart valve is expanded between the native leaflets of the native aortic annulus such that the proximal end of the stent is located below a proximal end of the native aortic annulus, and the prosthetic valve leaflets are in an open position, the entire free edge of each of the prosthetic valve leaflets may be located at least 10 mm above a free edge of each of the native leaflets. When the prosthetic heart valve is expanded between the native leaflets of the native aortic annulus such that the proximal end of the stent is located below a proximal end of the native aortic annulus, and the prosthetic valve leaflets are in an open position, the entire free edge of each of the prosthetic valve leaflets may be located between about 10 mm and about 20 mm above a free edge of each of the native leaflets.

The cuff may have top and bottom edges and may occupy a first group of the cells, such that the cells above the top edge are open cells at least partially devoid of the cuff, and when the prosthetic heart valve is expanded between the native leaflets of the native aortic annulus such that the proximal end of the stent is located below a proximal end of the native aortic annulus, at least a portion of each of the open cells may be located above a free edge of each of the native leaflets. When the prosthetic heart valve is expanded between the native leaflets of the native aortic annulus such that the proximal end of the stent is located below a proximal end of the native aortic annulus, each of the open cells may be located entirely above the free edge of each of the native leaflets.

The aortic section of the stent may include struts that form a plurality of independent fingers. Each of the fingers may extend distally from a distal apex of a respective one of the cells to a free end. Each of the fingers may have a length of at least 8 mm. Each of the free ends may be spaced from the free ends of the other fingers. The aortic section of the stent may include a connecting element extending about a circumference of the prosthetic heart valve between the fingers. The connecting element may include a porous material configured to permit tissue ingrowth.

A method of expanding a prosthetic heart valve between native leaflets of a native aortic annulus of a patient may include collapsing the prosthetic heart valve into a catheter, inserting the catheter into a patient, advancing the catheter into the native aortic annulus, and expanding the prosthetic heart valve in a selected position between the native leaflets of the native aortic annulus such that the native leaflets are compressed between an exterior surface of the prosthetic heart valve and native aortic tissue such that the proximal end of the stent is located below a proximal end of the native aortic annulus, and the prosthetic valve leaflets move to an open position upon the flow of blood there through.

The prosthetic heart valve may include a stent, a cuff attached to the stent, and a plurality of prosthetic valve leaflets attached to the cuff. The stent may have a proximal end, a distal end, an annulus section adjacent the proximal end, and an aortic section adjacent the distal end. The stent may include a plurality of struts shaped to form a plurality of cells connected to one another in a plurality of annular rows around the stent. The stent may define a flow direction from the proximal end toward the distal end. The prosthetic valve leaflets may be attached to the cuff between a first location and a second location distal to the first location in the flow direction. Each of the prosthetic valve leaflets may have a free edge. The selected position may selected such that the free edges of the prosthetic valve leaflets are located above free edges of the native leaflets when the prosthetic valve leaflets are in the open position.

The cuff may include a proximal cuff and a distal cuff. The proximal cuff may be coupled to a first group of the plurality of struts adjacent a bottom edge of the proximal cuff and may be coupled to a bottom edge of the distal cuff at a top edge of the proximal cuff. The distal cuff may be coupled to a second group of the plurality of struts adjacent a top edge of the distal cuff. When blood flows through the prosthetic valve leaflets, some of the blood may flow through open cells that are distal to the cuff in the flow direction and at least partially devoid of the cuff, over the free edges of the native valve leaflets, and into the coronary sinus ostia of the patient.

The entire free edge of each of the prosthetic valve leaflets may be located at least 10 mm above the free edge of each of the native leaflets when the prosthetic valve leaflets are in the open position. The entire free edge of each of the prosthetic valve leaflets may be located at least 25 mm above the proximal end of the stent when the prosthetic valve leaflets are in the open position.

Various embodiments of the present invention will now be described with reference to the appended drawings. It is to be appreciated that these drawings depict only some embodiments of the invention and are therefore not to be considered limiting of its scope.

DETAILED DESCRIPTION

There is a need for further improvements to the devices, systems, and methods of manufacturing collapsible prosthetic heart valves, and in particular, self-expanding prosthetic heart valves having cuffs. Among other advantages, the present invention may address one or more of these needs.

Embodiments of the present invention may include a prosthetic heart valve configured to be expanded between native leaflets of a native aortic annulus of a patient, having a cuff having a landing zone extending over a greater distance in the flow direction than conventional prosthetic heart valves. For example, as will be described more fully below, the cuff landing zone may extend at least one-third of the length of the stent in the flow direction between a bottom edge of the cuff and a proximal end of a most proximal cell of the open cells when the stent is in the expanded use condition. In another example, the cuff landing zone may extend at least 16 mm in the flow direction between the bottom edge of the cuff and a proximal end of a most proximal cell of the open cells when the stent is in an expanded use condition.

Embodiments of the present invention may also include a prosthetic heart valve configured to be expanded between native leaflets of a native aortic annulus of a patient, having the entire free edge of each of the prosthetic valve leaflets located at a greater distance from a proximal end of the stent in the flow direction than conventional prosthetic heart valves, which may permit the entire free edge of each of the prosthetic valve leaflets to be located more supra-annular when installed in a native aortic annulus than prosthetic valve leaflets of conventional prosthetic heart valves. For example, as will be described more fully below, the entire free edge of each of the prosthetic valve leaflets may be located at least three-fifths of a length of the stent above the proximal end of the stent when the prosthetic valve leaflets are in an open position and the stent is in an expanded use condition. In another example, the entire free edge of each of the prosthetic valve leaflets may be located at least about 25 mm above the proximal end of the stent when the prosthetic valve leaflets are in the open position and the stent is in the expanded use condition.

As used herein, the term “proximal,” when used in connection with a prosthetic heart valve, refers to the end of the heart valve closest to the heart when the heart valve is implanted in a patient, whereas the term “distal,” when used in connection with a prosthetic heart valve, refers to the end of the heart valve farthest from the heart when the heart valve is implanted in a patient. When used to indicate relative locations within the aortic annulus, the aortic root, and the ascending aorta of a patient, the terms “above” and “below” are to be taken as relative to the juncture between the aortic annulus and the left ventricle. “Above” is to be understood as relatively farther from the left ventricle, and “below” is to be understood as relatively closer to the left ventricle. As used herein, the words “about” and “approximately” are intended to mean that slight variations from absolute are included within the scope of the value recited, for example, due to manufacturing tolerances.

FIG. 1shows one such collapsible stent-supported prosthetic heart valve100known in the art. The prosthetic heart valve100is designed to replace the function of a patient's native tricuspid, bicuspid, or unicuspid valve, such as a native aortic valve. It should be noted that while the inventions herein are described predominately in connection with their use with a prosthetic aortic valve and a stent generally having a shape as illustrated inFIG. 1, the inventions may also be used with bicuspid valves, such as the mitral valve (e.g., as shown inFIG. 6), and with stents having different shapes, such as those having a flared or conical annulus section, a less-bulbous aortic section, and the like, and a differently shaped transition section. Examples of collapsible prosthetic heart valves are described in International Patent Application Publication No. WO/2009/042196; U.S. Pat. No. 7,018,406; and U.S. Pat. No. 7,329,278, the disclosures of all of which are hereby incorporated herein by reference.

The prosthetic heart valve100will be described in more detail with reference toFIG. 1. The prosthetic heart valve100includes an expandable stent102, which may be formed from biocompatible materials that are capable of self-expansion, such as, for example, shape memory alloys such as nitinol. The stent102extends from a proximal or annulus end130to a distal or aortic end132. The stent102includes an annulus section140adjacent the proximal end130and an aortic section142adjacent the distal end132. The annulus section140has a relatively small cross-section in the expanded condition, while the aortic section142has a relatively large cross-section in the expanded condition. Preferably, the annulus section140is in the form of a cylinder having a substantially constant diameter along its length, such as between about 12 mm and about 31 mm. A transition section141may taper outwardly from the annulus section140to the aortic section142.

Each of the sections140,141, and142of the stent102includes a plurality of struts that are shaped to form a plurality of cells112connected to one another in one or more annular rows around the stent. For example, as shown inFIG. 1, the annulus section140may have two annular rows of complete cells112, and the aortic section142and the transition section141may each have one or more annular rows of partial cells. The cells112in the aortic section142may be larger than the cells in the annulus section140. The larger cells in the aortic section142may better enable the prosthetic valve100to be positioned in the native valve annulus without the stent structure interfering with blood flow to the coronary arteries.

The stent102may include one or more retaining elements118at the distal end132thereof, the retaining elements being sized and shaped to cooperate with female retaining structures (not shown) provided on a deployment device configured to deploy the prosthetic valve100in the native valve annulus of a patient. Examples of female retaining structures configured to receive the one or more retaining elements118of the stent102and delivery devices configured to deploy the prosthetic valve100may be found in U.S. Patent Application Publication No. US2012/0078350, which is hereby incorporated by reference herein.

The engagement of the retaining elements118with female retaining structures on the deployment device helps maintain the prosthetic heart valve100in assembled relationship with the deployment device, minimizes longitudinal movement of the prosthetic heart valve relative to the deployment device during unsheathing or resheathing procedures, and helps prevent rotation of the prosthetic heart valve relative to the deployment device as the deployment device is advanced to the target location and the heart valve deployed. In some variations, the retaining elements118may be disposed near the proximal end130of the prosthetic heart valve100.

The prosthetic heart valve100also includes a valve assembly104, preferably positioned in the annulus section140of the stent102and secured to the stent. The valve assembly104includes a cuff106, and a plurality of leaflets108that collectively function as a one-way valve by coapting with one another. As a prosthetic aortic valve, the valve100has three leaflets108. However, it will be appreciated that other prosthetic heart valves with which the stent structures of the present invention may be used may have a greater or lesser number of leaflets. The base of the leaflets108may be sutured to other structure of the valve100. For example, this may result in securing the base of the leaflet through cuff material of the valve100.

Although the cuff106is shown inFIG. 1as being disposed on the luminal or inner surface of the annulus section140, it is contemplated that the cuff may be disposed on the abluminal or outer surface of the annulus section, or the cuff may cover all or part of either or both of the luminal and abluminal surfaces. Both the cuff106and the leaflets108may be wholly or partly formed of any suitable biological material or polymer such as, for example, PTFE.

The leaflets108may be attached along their belly portions to the cells112of the stent102, with the commissure between adjacent leaflets attached to commissure features116of the stent. Each leaflet108may have a free edge109that extends from a first commissure feature116ato a second commissure feature116b. The free edge109of each leaflet may have a first portion109athat extends from the first commissure feature116ato a triple point107where the three leaflets coapt, and a second portion109bthat extends from the triple point to the second commissure feature116b. The first portion109aand the second portion109btogether define the entire free edge109.

As can be seen inFIG. 1, each commissure feature116may lie at the intersection of four cells112of the stent102, two of the cells may be located adjacent one another in the same annular row, and the other two cells may be located in different annular rows and lie in end-to-end relationship. As shown inFIG. 1, the commissure features116may be positioned entirely within the annulus section140of the stent102or at the juncture of the annulus section and the transition section141. The commissure features116may include one or more eyelets that facilitate the suturing of the leaflet commissures to the stent.

The prosthetic heart valve100may be used to replace a native aortic valve, a surgical heart valve, a repair device, or a heart valve that has undergone a surgical procedure. The prosthetic heart valve may be delivered to the desired site (e.g., near the native aortic annulus) using any suitable delivery device. During delivery, the prosthetic heart valve is disposed inside the delivery device in a collapsed condition. The delivery device may be introduced into a patient using a transfemoral, transapical, transseptal or any other percutaneous approach. Once the delivery device has reached the target site, the user may deploy the prosthetic heart valve100out of the delivery device. Upon deployment, the prosthetic heart valve100expands so that the annulus section140is in secure engagement within the native aortic annulus. When the prosthetic heart valve is properly positioned inside the heart, it works as a one-way valve, allowing blood to flow from the left ventricle of the heart to the aorta, and preventing blood from flowing in the opposite direction.

FIG. 2is a highly schematic cross-sectional illustration of the prosthetic heart valve100disposed within a native valve annulus12. As seen inFIG. 2, the annulus section140of the stent102has a substantially circular cross-section that is disposed within the non-circular native valve annulus12. At certain locations around the perimeter of the heart valve100, crescent-shaped gaps24form between the heart valve and native valve annulus12. Blood flowing through these gaps and past the valve assembly104of the prosthetic heart valve100may cause regurgitation and other inefficiencies that reduce cardiac performance. Such improper fitment may be due to suboptimal native valve annulus geometry due, for example, to calcification of the native valve annulus12or to unresected native leaflets.

FIG. 3Ashows a developed view of a portion of the stent102of valve100. As can be seen inFIG. 3A, annulus section140extends a length H1 in the flow direction F of about 1.5 times the height of an annulus cell112a. The transition section141extends a length H2 in the flow direction F of about 0.5 times the height of an aortic cell112b, and the aortic section142extends a length H3 in the flow direction F of about 0.5 times the height of an aortic cell. The stent102extends a total length L1 in the flow direction F. L1 may preferably be no longer than 50 mm, more preferably between about 30 mm and about 50 mm. As shown inFIG. 3A, the commissure features116may be positioned at the juncture of the annulus section140and the transition section141, at a distance H1 from the proximal end130of the stent102.

The leaflets108may be attached to the first and second annular rows of cells R1, R2 of the stent102beginning a distance D1 from the proximal end130of the stent (approximately 0.5 times the height of an annulus cell112a), and extending in the flow direction F to the commissure features116.

FIG. 3Bshows the prosthetic valve100deployed in an aorta10of a patient, with the annulus section140of the stent102disposed at the native valve annulus12, the aortic section142contacting the ascending aorta16, and the transition section141extending across a portion of the aortic root14. When the prosthetic valve100is deployed in the aorta10, the native valve leaflets20are compressed against the native valve annulus12outside of the prosthetic valve.

It can be seen inFIG. 3Bthat in some patients, the free edges21of the compressed native valve leaflets20may extend to a height H4 in the flow direction F below which almost all of the annulus section140of the stent102is located once the valve100is deployed in the aorta10, such that one or more of the annulus cells112a(i.e., open cells) that are not filled with material of the tissue cuff106(e.g., two-thirds of the cells within the second row R2) may be located at least partially below the free edges of the compressed valve leaflets. As shown inFIG. 3B, one or more of the open annulus cells112amay be located entirely below the free edges of the compressed valve leaflets. Having one or more of the open annulus cells112alocated at least partially below the free edges of the compressed valve leaflets may occur either due to the design of the valve100or to deploying the valve relatively low, such that the proximal end130of the valve extends into the left ventricle.

In some circumstances, some of the blood that flows through the leaflets108and through the open cells112amay be impeded by the compressed native valve leaflets20that abut the open cells. As a result, some of the impeded blood may flow against the compressed native valve leaflets20and down between the native leaflets and the exterior of the valve100back into the left ventricle, for example, through the gaps24shown inFIG. 2. Such flow may cause regurgitation and other inefficiencies that may reduce cardiac performance, and may reduce blood flow into the coronary sinus ostia18.

FIG. 4Ashows a developed view of a portion of a stent202of a valve200(FIG. 4B). As can be seen inFIG. 4A, the annulus section240extends a length H5 in the flow direction F of about two times the height of an annulus cell212a. The transition section241extends a length H6 in the flow direction F of about 0.25 times the height of an aortic cell212b, and the aortic section242extends a length H7 in the flow direction F of about 0.25 times the height of an aortic cell. The stent202(or the stent302described below) extends a total length L2 in the flow direction F. L2 may preferably be no longer than 50 mm, more preferably between about 30 mm and about 50 mm. As shown inFIG. 4A, the commissure features216may be positioned at the juncture of the annulus section240and the transition section241, at a distance H5 from the proximal end230of the stent202. When the stent202(or the stent302) is in an expanded use condition, the stent may have a minimum diameter in a direction perpendicular to the flow direction between about 20 mm and about 25 mm, preferably about 23 mm. When the stent202(or the stent302) is in an expanded use condition, the length L2 may be greater than the minimum diameter of the stent.

The annulus section240of the stent202may include three annular rows of cells212a, and the aortic section242of the stent may include one annular row of cells212b, the row of cells in the aortic section having a greater length in the flow direction F than each of the rows of cells in the annulus section. The rows of cells in the annulus section240together may have a greater combined length in the flow direction F than the row of cells in the aortic section242.

The stent202may include one or more retaining elements218at the distal end232thereof, the retaining elements being sized and shaped to cooperate with female retaining structures (not shown) provided on a deployment device configured to deploy the prosthetic valve200in the native valve annulus12of a patient. As can be seen inFIG. 4A, the stent202may include a retaining element218extending distally from the apex of each of the aortic cells212bthat has one of its struts extending through a commissure feature216.

Compared to the retaining elements118ofFIG. 3A, the retaining elements218ofFIG. 4Amay be larger and may have a greater radius of curvature, which may help prevent the retaining elements from eventually migrating to penetrate the wall of the ascending aorta after the valve200has been deployed into the patient. For example, the retaining elements118ofFIG. 3Amay have a radius between about 1.0 mm and about 1.8 mm, and the retaining elements218ofFIG. 4Amay have a radius between about 1.8 mm and about 3.0 mm.

The leaflets208may be attached to second and third rows of cells R2, R3 of the stent202beginning a distance D2 from the proximal end230of the stent (approximately equal to the height of an annulus cell212a), and extending in the flow direction F to the commissure features216.

FIG. 4Bshows the prosthetic valve200deployed in an aorta10of a patient, with the annulus section240of the stent202disposed at the native valve annulus12, the aortic section242contacting the ascending aorta16, and the transition section241extending across a portion of the aortic root14. When the prosthetic valve200is deployed in the aorta10, the native valve leaflets20are compressed against the native valve annulus12outside of the prosthetic valve. The expanded diameter of the annulus section240of the stent202may preferably be between about 12 mm and about 31 mm.

It can be seen inFIG. 4Bthat in some patients, the free edges21of the compressed native valve leaflets20may extend to height H4 in the flow direction F. Since the annulus section240of the stent202is longer than the annulus section140of the stent102, a larger portion of the annulus section240may extend above the height H4 compared to the annulus section140, such that one or more of the cells212athat are at least partially devoid of material of the tissue cuff206(e.g., two-thirds of the cells within the third row R3) may be located above the free edges of the compressed valve leaflets. The longer annulus section240compared to the annulus section140, and the longer cuff206compared to the cuff106, may provide a user a broader range for positioning the valve200relative to the native aortic annulus while still providing an effective seal between the cuff206and the native aortic annulus and native leaflets20.

For example, a landing zone (i.e., continuous cylindrical portion) of the cuff206may extend over a length of about 16 mm to about 18 mm in the flow direction F between the proximal end230of the stent202and the lowest open cell212a, compared to a landing zone of about 8 mm to about 10 mm for the cuff106, when the stent is in an expanded use condition. The landing zone may extend over a length of at least 12 mm in the flow direction F, preferably at least 14 mm, more preferably at least 16 mm, and most preferably at least 18 mm, when the stent202is in an expanded use condition. The landing zone may extend over a length of at least one-third of the length L2 of the stent202in the flow direction F. The entire free edge209of each of the prosthetic valve leaflets208may be located within a distance D6 in the flow direction F from the distal end232of the stent202when the prosthetic valve leaflets are in the open position and the stent is in the expanded use condition, the distance D6 being less than a length of the landing zone in the flow direction. In such an embodiment, D6 may be about 13 mm, for example, and the landing zone may be about 16 mm.

As used herein, a stent102,202, or302is in an “expanded use condition” when the stent is radially expanded between native leaflets of the native aortic annulus, or radially expanded to the same extent as it would be between native leaflets of the native aortic annulus. All dimensions in the flow direction as described herein are to be taken when the stent is in an expanded use condition.

In the example shown inFIG. 4B, the entire free edge209of each of the prosthetic valve leaflets208may be located above the free edge21of each of the compressed native valve leaflets20when the prosthetic valve leaflets are in an open position (i.e., allowing blood to flow therethrough). For example, the entire free edge209of each of the prosthetic valve leaflets208may be located at least 10 mm above the free edge21of each of the compressed native valve leaflets20, preferably between about 10 mm and about 20 mm above the free edge of each of the compressed native valve leaflets. The entire free edge209of each of the prosthetic valve leaflets208may be located at least 25 mm above the proximal end230of the stent202when the prosthetic valve leaflets are in the open position, preferably between about 25 mm and about 40 mm above the proximal end of the stent. The entire free edge209of each of the prosthetic valve leaflets208may be located at least three-fifths of the length of the stent202above the proximal end230of the stent when the prosthetic valve leaflets are in the open position.

As can be seen by comparingFIGS. 3A and 4A, when the prosthetic valve leaflets are in an open position, the entire free edge209of each of the leaflets208is located higher than each of the free edges109of the leaflets108, which may permit the valve200to have better blood flow to the coronary sinus ostia18than the valve100. In some circumstances, most or all of the blood that flows through the leaflets208and through the open cells212amay flow above the free edges21of the native valve leaflets20, and thereby not be impeded by the native valve leaflets. As such, the blood may have an improved flow path to the coronary sinus ostia18, which may help prevent regurgitation and other inefficiencies that may reduce cardiac performance. When deployed in the aorta10, the valve200having open annulus cells212aabove the free edges21of the compressed native valve leaflets20may produce less regurgitation than the valve100.

One potential way to achieve the result of the entire free edges of the leaflets of prosthetic valve100being located above the free edges21of the compressed valve leaflets20would be to deploy the valve higher in the aorta, that is, farther away from the left ventricle. However, positioning the proximal end of the stent130too high relative to the native aortic annulus12is not desirable because a valve deployed in this position may only contact a small portion of the native aortic annulus, thereby making the valve more difficult to position and more prone to migration as the native aortic annulus would not be able to effectively grip the prosthetic valve. It is preferable that the proximal end of the stent130be placed no higher than the lowest portion of the native aortic annulus12(i.e., the portion that is closest to the left ventricle).

The valves200and300described herein may achieve the result of the free edges of the prosthetic leaflets being located above the free edges21of the compressed valve leaflets20when the prosthetic valve leaflets are in an open position, while at the same time lengthening the annulus section of the prosthetic valve relative to conventional prosthetic valves so that the native aortic annulus12can effectively grip the prosthetic valve.

The length L2 of the valve200(FIG. 4B) is less than the length L1 of the valve100(FIG. 3B), such that the valve200extends a shorter distance from the proximal end22of the aortic annulus12than the valve100. Because the valve200when deployed does not extend as far into the ascending aorta as the valve100, the valve200may avoid contacting weaker sections of the ascending aorta in patients having atypical morphology of the aortic root and ascending aorta compared to a typical patient (e.g., patients having aortic insufficiency, relatively young patients, and patients having bicuspid or monocuspid native aortic valves), which may help prevent aortic dissection in such atypical patients.

The cuff206shown inFIGS. 4A and 4Bmay include a proximal cuff250and a distal cuff252. The proximal cuff250and the distal cuff252may either be proximal and distal portions of a single unitary cuff, or the proximal and distal cuffs may be initially separate from one another and coupled together along a boundary line by stitching, for example.

Each of the cuffs250and252may be disposed on the luminal or inner surface of the annulus section240, the abluminal or outer surface of the annulus section, or the cuffs may each cover all or part of either or both of the luminal and abluminal surfaces. Each of the cuffs250and252may be wholly or partly formed of any suitable biological material or polymer or suitable combination thereof such as, for example, PTFE, PET, or ultra high molecular weight polyethylene (UHMWPE).

The proximal cuff250and the distal cuff252may be made from different materials. The cuff206may include a thinner material in the distal cuff252region that will add as little bulk as possible to the space occupied by the leaflets208so as to minimize the crimped diameter of that portion of the cuff. The cuff206may include a thicker and/or expandable material in the proximal cuff250region that does not significantly overlap with the leaflets208, so that improved sealing against the native annulus12may be obtained with no impact or a minimal impact on the crimped diameter of the cuff. The proximal cuff250may have a first average thickness in a radial direction perpendicular to the flow direction F, and the distal cuff252may have a second average thickness in the radial direction, the first average thickness being greater than the second average thickness.

The proximal cuff250may be made of or may include a relatively porous material that is suitable for tissue ingrowth from the native annulus and/or sealing against the native annulus12, such as a woven or braided fabric material. For example, the proximal cuff250may incorporate polyvinyl alcohol (PVA), PET, UHMWPE, felt-like fabric, foam shape memory portions, or a sponge-like portion into the material of the cuff. The proximal cuff250may include radiopaque fiber woven into a base material of the proximal cuff, or one or more sections of the proximal cuff may be radiopaque. The proximal cuff250may be formed from a porous membrane embedded with microspheres that may swell in size when exposed to blood after the valve200has been deployed in the aorta10. The enlarged cuff may then fill the gaps (e.g., the gaps24) between the native valve annulus12and the prosthetic heart valve200, minimizing or preventing perivalvular leakage. Other examples of suitable porous and/or expanding materials for the proximal cuff250may be found in co-pending and co-owned U.S. patent application Ser. No. 13/829,036, which is hereby incorporated herein by reference. Furthermore, as shown inFIG. 4B, the proximal cuff250and the distal cuff252may have different fiber orientations to customize the strength and/or wear resistance of the proximal cuff and the distal cuff in particular directions relative to the native annulus12.

As can be seen inFIG. 4B, the proximal cuff250extends from the proximal end230of the stent202across the distance D2 in the flow direction F (approximately equal to the height of an annulus cell212a), such that the proximal cuff and the leaflets208have either no overlap or a small amount of overlap in the flow direction. The proximal cuff250may extend into the first annular row R1 of complete cells212aadjacent the proximal end230of the stent202.

The distal cuff252may be made of or may include a relatively thin, less porous, and abrasion resistant material that is suitable for protecting the leaflets208from abrasion while permitting the valve200to have as small a diameter as possible while in a radially collapsed position in a delivery device. For example, the distal cuff252may be made of or may include a synthetic material such as polyester, PFTE, PET, UHMWPE, electrospun materials (e.g., electrospun collagen or fibrin), collagen-impregnated PET, or a suitable combination thereof. The distal cuff252material may be in the form of one or more sheets, rather than a woven or braided fabric. The distal cuff252may also include one or more sections of radiopaque material. Such synthetic materials may enable a thinner distal cuff252to be produced, resulting in a lower crimped diameter for the valve200, as well as the need for less force for loading and resheathing. The use of synthetic materials may also increase the durability and life expectancy of the distal cuff252. Other examples of suitable thin and durable materials for the distal cuff252may be found in co-pending and co-owned U.S. patent application Ser. No. 13/829,036.

As can be seen inFIG. 4B, the distal cuff252may be attached to the stent202beginning a distance D3 from the proximal end230of the stent (approximately 0.5 times the height of an annulus cell212a), and may extend in the flow direction F to the commissure features216, for a total distance D4 (approximately 1.5 times the height of an annulus cell212a). The distal cuff252may extend into the second annular row R2 of complete cells212aand may also extend into some cells of the third annular row R3 of complete cells212a. Two-thirds of the annulus cells212aof this third annular row R3 may be unoccupied or only partially occupied by material of the distal cuff252, so that blood may flow through these unoccupied annulus cells to the coronary sinus ostia18. The distal cuff252preferably extends into those annulus cells212aof the third annular row R3 immediately below the commissure features216.

The distal cuff252may be sutured to the proximal cuff250along a boundary line254that extends along the border between adjacent rows of complete annulus cells212a. At least a portion of the distal cuff252may extend across the same portion of the stent202in the flow direction F as the leaflets208, such that the location of the distal cuff in the flow direction partially overlaps the location of the leaflets.

FIG. 5shows a prosthetic valve300deployed in the aorta10of a patient, with the annulus section340of the stent302disposed at the native valve annulus12, the aortic section342contacting the ascending aorta16, and the transition section341extending across a portion of the aortic root14. Similar toFIGS. 3B and 4B, when the prosthetic valve300is deployed in the aorta10, the native valve leaflets20are compressed against the native valve annulus12outside of the prosthetic valve.

As can be seen inFIG. 5, the annulus section340extends a length H5 in the flow direction F of two times the height of an annulus cell312a. The transition section341extends a length H8 in the flow direction F, and the aortic section342extends a length H9 in the flow direction F. The commissure features316may be positioned at the juncture of the annulus section340and the transition section341, at a distance H5 from the proximal end330of the stent302. Rather than comprising complete cells312or parts of complete cells, the transition section341and the aortic section342comprise portions of independent fingers313, each finger extending distally from the apex of a respective one of the annulus cells312ain the most distal row of cells. Each finger313preferably may extend distally at least 5 mm from the apex of a respective one of the annulus cells312ain the most distal row of cells, more preferably at least 8 mm, most preferably at least 10 mm. Each finger313may have a free end314that is not connected to the free end of any of the other fingers.

The stent302may include one or more retaining elements318at the distal end332thereof, the retaining elements being sized and shaped to cooperate with female retaining structures (not shown) provided on a deployment device configured to deploy the prosthetic valve300in the native valve annulus12of a patient. The retaining elements318may be either the retaining elements118ofFIGS. 3A and 3Bor the retaining elements218ofFIGS. 4A and 4B.

Similar to the leaflets208shown inFIG. 4B, the leaflets308of the prosthetic valve may be attached to the second and third rows of cells R2, R3 of the stent302beginning slightly below a distance D2 from the proximal end330of the stent (approximately equal to the height of an annulus cell312a) and extending in the flow direction F to the commissure features316.

Similar toFIG. 4B, in some patients, the free edges21of the compressed native valve leaflets20may extend to height H4 in the flow direction F. Since the annulus section340of the stent302is longer than the annulus section140of the stent102, a larger portion of the annulus section340may extend above the height H4 compared to the annulus section140, such that one or more of the cells312athat are at least partially devoid of material of the tissue cuff306may be located above the free edges of the compressed valve leaflets. The longer annulus section340compared to the annulus section140, and the longer cuff306compared to the cuff106, may provide a user a broader range for positioning the valve300relative to the native aortic annulus while still providing an effective seal between the cuff306and the native aortic annulus and native leaflets20.

For example, a landing zone (i.e., continuous cylindrical portion) of the cuff306may extend over a length of about 16 mm to about 18 mm between the proximal end330of the stent302and the lowest open cell312a, compared to a landing zone of about 8 mm to about 10 mm for the cuff106. The landing zone may extend over a length of at least one-third of the length of the stent302in the flow direction F. The entire free edge309of each of the prosthetic valve leaflets308may be located within a distance D6 in the flow direction F from the distal end332of the stent302when the prosthetic valve leaflets are in the open position and the stent is in the expanded use condition, the distance D6 being less than a length of the landing zone in the flow direction. In such an embodiment, D6 may be about 13 mm, for example, and the landing zone may be about 16 mm.

In the example shown inFIG. 5, the entire free edge309of each of the prosthetic valve leaflets308may be located above the free edge21of each of the compressed native valve leaflets20when the prosthetic valve leaflets are in an open position. For example, the entire free edge309of each of the prosthetic valve leaflets308may be located at least 10 mm above the free edge21of each of the compressed native valve leaflets20, preferably between about 10 mm and about 20 mm above the free edge of each of the compressed native valve leaflets. The entire free edge309of each the prosthetic valve leaflets308may be located at least 25 mm above the proximal end330of the stent302when the prosthetic valve leaflets308are in the open position, preferably between about 25 mm and about 40 mm above the proximal end of the stent. The entire free edge309of each of the prosthetic valve leaflets308may be located at least three-fifths of the length of the stent302above the proximal end330of the stent when the prosthetic valve leaflets are in the open position.

In such an example, similar to the valve200, some of the blood that flows through the leaflets308may flow through the open cells312a, over the free edges21of the compressed native valve leaflets20into the aortic root14, and into the coronary sinus ostia18. This flow pattern may be desirable because there may be an unimpeded flow of blood through the open cells312aover the free edges21of the native leaflets20to the coronary sinus ostia18, compared to the valve100in certain situations, in which the flow of blood through the open cells112amay be impeded by the native leaflets that abut the open cells.

The cuff306shown inFIG. 5may include a proximal cuff350and a distal cuff352. The proximal cuff350and the distal cuff352may either be proximal and distal portions of a single unitary cuff, or the proximal and distal cuffs may be initially separate from one another and coupled together along a boundary line by stitching, for example. Each of the cuffs350and352may be disposed on the luminal or inner surface of the annulus section340, the abluminal or outer surface of the annulus section, or the cuffs may each cover all or part of either or both of the luminal and abluminal surfaces. Each of the cuffs350and352may be wholly or partly formed of any suitable biological material or polymer such as, for example, PTFE.

The proximal cuff350and the distal cuff352may be made from different materials. Similar to the cuff206, the cuff306may include a thinner material in the region of the distal cuff352that will add as little bulk as possible to the space occupied by the leaflets308so as to minimize the crimped diameter of that portion of the prosthetic valve. The cuff306may include a thicker and/or expandable material in region of the proximal cuff350that does not significantly overlap with the leaflets308, so that improved sealing against the native annulus12may be obtained with no impact or a minimal impact on the crimped diameter of the cuff. The proximal cuff350may be made of or may include any of the materials described above with reference to the proximal cuff250, and the distal cuff352may be made of or may include any of the materials described above with reference to the distal cuff252.

As can be seen inFIG. 5, the proximal cuff350extends from the proximal end330of the stent302across the distance D2 in the flow direction F (approximately equal to the height of an annulus cell312a), such that the proximal cuff and the leaflets308have either no overlap or a small amount of overlap in the flow direction. The proximal cuff350may extend into the first annular row R1 of complete cells312aadjacent the proximal end330of the stent302and into the proximal half of the second annular row R2 of complete cells.

The distal cuff352may be attached to the stent302beginning a distance D2 from the proximal end330of the stent, extending in the flow direction F to the commissure features316, for a total distance D5 (approximately equal to the height of an annulus cell312a). The distal cuff352may extend into the distal half of the second annular row R2 of complete cells312aand may also extend into some cells of the third annular row R3 of complete cells312a. Two-thirds of the annulus cells312aof this third annular row R3 may be unoccupied or only partially occupied by material of the distal cuff352, so that blood may flow through these unoccupied annulus cells to the coronary sinus ostia18. The distal cuff352preferably extends into those annulus cells312aof the third annular row immediately below the commissure features316.

As shown inFIG. 5, the proximal cuff350may have a cylindrical shape that joins the distal cuff352in a substantially circular closed curve, the curve lying in a plane generally perpendicular to the flow direction as opposed to the zig-zag configuration of the boundary between the proximal and distal cuffs250and252shown inFIGS. 4A and 4B. The distal cuff352may be sutured to the proximal cuff350along a boundary line354that extends in a closed curve annularly about the circumference of the stent302. At least a portion of the distal cuff352may extend across the same portion of the stent302in the flow direction F as the leaflets308, such that the location of the distal cuff in the flow direction partially overlaps the location of the leaflets.

The distal cuff350may have pockets356that may be formed from a porous membrane embedded with microspheres that may swell in size when exposed to blood after the valve300has been deployed in the aorta10. The enlarged pockets356may then help fill the gaps (e.g., the gaps24) between the native valve annulus12and the prosthetic heart valve300, minimizing or preventing perivalvular leakage. The proximal edge of the pockets356may form a parabolic pattern that approximately follows the locations at which the leaflets308are sutured to the stent302and/or the cuff306. Other examples of suitable porous and/or expanding materials for the pockets356and potential shapes and configurations of the pockets may be found in co-pending and co-owned U.S. patent application Ser. No. 13/829,036.

Because the transition section341and the aortic section342comprise portions of independent fingers313that do not form closed cells like the aortic cells112band212bdescribed above, the transition and aortic sections of the valve300may be less resistant to deflection in a radial direction R that is generally perpendicular to the flow direction F. That is, when deployed, the aortic section342of the stent302may apply a lower radially-expansive force against a portion of the ascending aorta than the aortic section142of the stent102or the aortic section242of the stent202. Therefore, the aortic section342of the valve300may be less likely to penetrate weaker sections of the ascending aorta in patients having atypical morphology of the aortic root and ascending aorta compared to a typical patient (e.g., patients having aortic insufficiency, relatively young patients, and patients having bicuspid or monocuspid native aortic valves), which may help prevent aortic dissection in such atypical patients.

The valve300may optionally include a connecting element360extending about the circumference of the valve between the independent fingers313in the aortic section342. The connecting element360may be made of or may include a relatively porous material that is suitable for tissue ingrowth from the ascending aorta16, such as a fabric material, for example. Such a connecting element360may help reinforce weaker sections of the ascending aorta in patients having atypical morphology of the aortic root and ascending aorta compared to a typical patient, which may help prevent aortic dissection in such atypical patients.

Although the proximal cuff350and the distal cuff352are shown inFIG. 5and described as being joined along a boundary line354that extends in a closed curve extending annularly about the circumference of the stent302in a plane generally perpendicular to the flow direction, that need not be the case. The cuff306may alternatively include the proximal cuff250and the distal cuff252described above with respect toFIGS. 4A and 4Bas having a zig-zag shaped boundary, joined together in substantially the same way as described.

FIG. 6shows the prosthetic valve200or300deployed in a native mitral annulus11of a patient, with the proximal end230,330of the stent disposed in the left atrium13and the distal end232,332of the stent disposed in the left ventricle15. The prosthetic valve200or300may be installed in the native mitral annulus11, such that the native valve leaflets are compressed against the native mitral annulus outside of the prosthetic valve. Using the prosthetic valve200or300in the native mitral annulus11may minimize interference between the distal end232,332of the stent and the chordae tendineae in the left ventricle compared to conventional prosthetic valves, due to the relatively short aortic section of the valve200,300.

The distal end of the stent extending into the left ventricle may be designed not to flare radially outward relative to the proximal end230,330of the stent. Such a design may further minimize interference between the distal end232,332of the stent and the chordae tendineae. The proximal end230,330of the stent extending into the left atrium may be designed to flare radially outward relative to the distal end232,332of the stent. Such a design may enhance sealing of the valve200or300against the native mitral annulus11. As described above with respect toFIGS. 4B and 5, the valve200or300may have proximal and distal cuffs made from different materials or having different thicknesses, so that improved sealing against the native mitral annulus11may be obtained with no impact or a minimal impact on the crimped diameter of the cuff.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It will be appreciated that the various dependent claims and the features set forth therein can be combined in different ways than presented in the initial claims. It will also be appreciated that the features described in connection with individual embodiments may be shared with others of the described embodiments.