Patent Application
20240156591
The present application relates generally to replacement heart valves, for example, for replacing diseased mitral and/or tricuspid valves. More particularly, the present application relates to tissue-based, collapsible and expandable replacement heart valves and to systems and methods for implanting such valves.
The mitral valve (MV) has two distinct large leaflet cusps, or leaflets. As shown in
When the mitral valve is closed, the respective anterior and posterior leaflets are in close contact to form a single zone of apposition. As one skilled in the art will appreciate, normal mitral valve function involves a proper force balance, with each of its components working congruently during a cardiac cycle. Pathological alterations affecting any of the components of the mitral valve, such as chord rupture, annulus dilatation, papillary muscle displacement, leaflet calcification, and myxomatous disease, can lead to altered mitral valve function and cause mitral valve regurgitation (MR).
Mitral regurgitation, shown in
The current treatments for mitral valve diseases include surgical repair and replacement of the mitral valve. Mitral valve repair, benefiting from improved understanding of mitral valve mechanics and function, may be now preferred to complete mitral valve replacement. However, the complex physiology and three-dimensional anatomy of the mitral valve and its surrounding structure present substantial challenges when performing these repair procedures.
In one early example of a transcatheter mitral valve replacement device, Endovalve-Herrmann (Micro Interventional Devices, Inc.) developed a mitral prosthesis that had a foldable Nitinol-based valve with a sealing skirt. Similarly, Tendyne Holdings, Inc. produces a prosthetic mitral valve replacement device comprising a pericardial valve with a self-expandable Nitinol stent. The device is designed for transapical delivery and has a ventricular fixing anchor. CardiAQ uses a pericardial valve with a Nitinol self-expandable stent in their mitral valve replacement device. Finally, Tiara (Neovasc, Inc.) uses a mitral valve replacement system that is deliverable trans-apically with a 30 Fr catheter that has anchor structures, and a pericardial valve on a self-expandable stent with a D-shaped atrial portion and a ventricular portion that has an outer coating. These devices and the techniques to deliver the mitral prosthesis into the operative position are still at development stages and, though promising, challenges to the efficacy of these devices continue to exist.
The noted challenges to an efficacious mitral valve replacement device generally include operative delivery challenges; positioning and fixation challenges; seal and paravalvular leakage challenges; and hemodynamic function challenges such as left ventricular outflow tract (LVOT) obstruction and possible mitral stenosis. With respect to the noted operative delivery challenges, since a conventional mitral prosthetic is larger than a conventional aortic prosthesis, it is more difficult to fold and compress the larger mitral prosthesis into a catheter for deployment as well as retrieval through either conventional trans-apical or trans-femoral delivery techniques.
Turning to the positioning and fixation challenges, instability and migration are the most prominent obstacles given that the mitral valve is subjected to high and repetitive loads in a cardiac cycle, with a high transvalvular pressure gradient that is near zero at diastole and can rise to 120 mmHg or more during systole and higher than 150 mmHg of systolic pressure for patients with aortic stenosis and systemic hypertension. The lack of calcium distribution at the mitral annulus also affects device stability and anchoring. Further, the transcatheter mitral valve replacement can be easily dislodged as the heart moves during each beating cycle.
With respect to sealing and paravalvular leakage, good sealing between the native annulus and the prosthesis that minimizes paravalvular leak is desirable. Conventionally, a prosthetic mitral valve is smaller than the diseased native valve and additional material is added around the prosthetic valve to compensate for the large native mitral annulus. Undesirably, adding more material to a prosthetic valve increases the size of the delivery system. Further, this can create an elevated forward flow pressure gradient across the valve or even stenosis.
Finally, with respect to the preservation of hemodynamic function, the operative positioning of a prosthetic mitral valve, which is conventionally large as described above, should not obstruct the mitral orifice during diastole or the LVOT at the anterior portion of the mitral annulus during systole.
Posterior mitral valve repair techniques such as Polares and Half-moon consist of a non-mobile posterior coaptation surface for the native anterior mitral valve and thus avoid LVOT obstruction.
Accordingly, it would be beneficial to have a heart valve leaflet replacement system that does not suffer from the shortcomings and deficiencies of conventional valve prosthetics. For example, it may be desirable to secure the prosthetic mitral valve replacement system to the native mitral annulus. It may also be desirable to improve positioning of a mitral prosthesis and prevent leaking of blood between the mitral prosthesis and the native mitral valve without creating stenosis. Similarly, it may be desirable to prevent further dilation of the native mitral annulus. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.
The present application is directed generally to prosthetic heart valves and methods for implanting prosthetic heart valve, and, more particularly, to low-profile prosthetic hemi heart valves or prosthetic hemi-valves configured to fill a regurgitant orifice area during systole to treat mitral regurgitation without restricting diastolic filling of the left ventricle. It is contemplated that the low-profile prosthetic hemi-valves herein can be implanted via an open surgical procedure or percutaneously via catheter. For clarity, it will be appreciated that, although this disclosure may focus on the treatment of functional mitral regurgitation, it is contemplated that the low-profile prosthetic hemi-valves and the associated methods can be used or otherwise configured to be used to treat other valve disease conditions such as degenerative mitral regurgitation and regurgitation of other valves (e.g., tricuspid valve) of the human heart, or could be used or otherwise configured to be used in other mammals suffering from valve deficiencies as well.
In one aspect, the low-profile prosthetic hemi-valve is configurable or otherwise sizable to be crimped down to fit within a delivery catheter and to subsequently be selectively re-expanded to an operative size and position once removed from the delivery catheter within the heart. In a further aspect, the low-profile prosthetic hemi-valve can comprise a stent, with an open lower ventricular portion attached to a radially flared out upper portion, where an angled neck portion forms a transition between the upper and lower portions of the hemi-valve.
In one aspect, the upper portion can be configured to facilitate anchoring of the stent, which can help prevent dislodgement of the stent. The lower portion can be suspended in the blood flow tract and house at least one flexible prosthetic leaflet. In another aspect, the prosthetic hemi-valve can comprise a sealing skirt that can be coupled to at least a portion of the inner and/or outer surfaces of the stent.
In one exemplary aspect, at least one prosthetic leaflet can be mounted on the inner lumen of the stent and/or on at least a portion of the outer side of the stent. The at least one flexible prosthetic leaflet can be configured to be mobile throughout the cardiac cycle and coapt with at least one native valve leaflet. The lower portion of the stent frame can also be configured as a coaptation surface for one or more native heart valve leaflets.
In one aspect, the upper portion of the low-profile prosthetic hemi-valve is configured with a large diameter and flared out shape for annular anchoring and atrial apposition. The lower portion of the low-profile prosthetic hemi-valve has a fish mouth-shape, resembling the healthy native mitral valve coaptation line. An angled neck region forms a transition between the upper and lower portions of the hemi-valve.
In one example, the low-profile prosthetic hemi-valve device can comprise a partial elliptical, upper stent portion that is configured for posterior mitral annulus anchoring from one trigone to the other. The lower portion of the frame can comprise a smaller fish mouth-shape with a larger major axis corresponding to the commissure-to-commissure anatomical direction and a smaller minor axis corresponding to the anterior-to-posterior anatomical direction of the mitral annulus. In this example, the lower portion is attached to the upper portion such that it is suspended in the blood flow path near the native mitral valve coaptation line in the operative position. At least one flexible prosthetic leaflet can be attached to the inner surface of the lower portion of the frame, wherein it is configured to be mobile throughout the cardiac cycle, and coapt with at least a portion of the native anterior mitral leaflet. Further in this example, the native posterior and commissure mitral leaflets are undisturbed and can move normally and coapt with the outer surface of the lower portion of the frame, such that during systole, the entire mitral orifice is sealed closed. During diastole, the blood flow can push the at least one prosthetic leaflet towards the inner surface of the lower portion of the frame, such that flow between the device and the native anterior mitral leaflet is uninhibited. Further in this example, the frame can comprise at least one flow channel in the upper and/or neck portion of the frame to promote diastolic flow between the native posterior mitral leaflet and the outer surface of the lower portion of the frame.
In another example, the upper stent portion can be configured as a full ring to be anchored on the mitral annulus.
Someone skilled in the art can appreciate that, in some circumstances, it is desirable to have a large upper stent portion to facilitate device anchoring because many patients with mitral regurgitation have a large, dilated mitral annulus, but a smaller lower portion supporting the at least one prosthetic leaflet, such that the device can be more easily crimped into a low-profile diameter for safer transcatheter delivery and implantation. Furthermore, a smaller structure within the native valve and ventricle may be desirable because it has minimal impact on the surrounding native tissues. In the case of functional mitral regurgitation, the mitral valve apparatus is often functional; the regurgitant orifice is the result of dilation of the heart. The native leaflets can no longer fully coapt with each other but can still help with sealing around the implant. The at least one flexible prosthetic leaflet can cover the regurgitant orifice. Smaller prosthetic leaflets are also beneficial for implant durability given their smaller surface area, they experience less load.
In some circumstances, it may be desirable for the prosthetic valve to have an effective orifice area similar to the native valve. Otherwise, the patient could experience an elevated pressure gradient or stenosis across the replacement valve. Someone skilled in the art can appreciate that the effective orifice area of the mitral valve is naturally reduced by implantation of a prosthetic valve with a smaller diameter than the native annulus. The at least one flow channel through the frame in this example, can significantly increase the effective orifice area of the prosthetic hemi-valve and help maintain normal function of the native mitral leaflets.
In one example, the minor axis of the lower portion of the frame is smaller than that of the upper portion. The major axis of the lower portion of the frame is the same or similar to the minimum major axis dimension of the upper portion of the frame. In this example, the lower portion of the frame follows a shallower curve compared to the upper portion. Thus, the neck portion at the minor axis of the device extends radially inward from the upper portion to the lower portion of the frame. The neck at the major axis of the device is nearly vertical.
In one aspect, at least one prosthetic leaflet can be mounted to the inner surface of the lower portion of the stent frame. The prosthetic leaflet can be configured to be flexible and mobile throughout the cardiac cycle. During the systolic phase, the at least one prosthetic leaflet extends to coapt with native anterior leaflets by extending radially outwards from the lower portion of the frame to prevent leakage between the anterior surface of the implant and the native anterior leaflet, while the native posterior leaflets extend to coapt with the outer surface of the lower portion of the frame to prevent leakage between the posterior surface of the implant and the native posterior leaflet. During diastole, the at least one prosthetic leaflet is configured to move towards the lower portion of the frame to allow for blood to flow from the left atrium to the left ventricle between the anterior surface of the implant and the native anterior leaflet while the at least one flow channel in the neck region of the frame allows blood to flow from the left atrium to the left ventricle between the posterior surface of the implant and the native posterior leaflet.
In one example, the at least one prosthetic leaflet can mimic the configuration of the native mitral posterior leaflets with three adjoined semilunar cusps on the lower portion of the stent.
In one aspect, the sealing skirt material can be made of polymers, fabric, biological tissue, and the like. The skirt can be a single piece of material, or alternatively, the skirt can be configured from multiple separate pieces of material, coupled to the frame via non-absorbable suture or string. It is contemplated that the skirt material can be configured to promote tissue in-growth at the annulus, and protect against abrasion between the frame and surrounding anatomic structures.
In one aspect, delivery of the low-profile prosthetic hemi-valve can be conducted using several desired delivery access approaches, such as, for example and not meant to be limited to, a surgical approach, a trans-septal approach, a trans-atrial, or a trans-apical approach. In one exemplary aspect, the trans-septal approach can comprise creating an opening in the internal jugular or femoral vein for the subsequent minimally invasive delivery of portions of the low-profile prosthetic hemi-valve through the superior vena cava, which flows into the right atrium of the heart. In this exemplary aspect, the access path of the trans-septal approach crosses the atrial septum of the heart, and once achieved, the components of the prosthetic hemi-valve can operatively be positioned in the left atrium, the native mitral valve, and the left ventricle. In one aspect, it is contemplated that a main delivery catheter can be placed therein the access path to allow desired components of the prosthetic hemi-valve to be operatively positioned in the left atrium without complications.
It can be appreciated by an individual skilled in the art that due to the nature of the implant that is designed to fill a regurgitant orifice between native leaflets versus an entire native leaflet and/or valve, it naturally has a smaller profile, compared to a full valve or large coaptation surface, allowing a greater portion of the at-risk population to undergo a transcatheter mitral valve replacement operation.
In one aspect, a plurality of dual guiding and fixation members can be operatively positioned and implanted at desired locations in the native annulus prior to the delivery of the replacement prosthetic hemi-valve. In this aspect, the dual guiding and fixation members can improve the subsequent positioning and anchoring of the replacement prosthetic hemi-valve.
Various implementations described in the present application can include additional systems, methods, features, and advantages, which can not necessarily be expressly disclosed herein but will be apparent to one of ordinary skill in the art upon examination of the following detailed description and accompanying drawings. It is intended that all such systems, methods, features, and advantages be included within the present application and protected by the accompanying claims.
It is believed the present invention will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:
The drawings are not intended to be limiting in any way, and it is contemplated that various examples of the invention may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown.
The devices and methods herein can be understood more readily by reference to the following detailed description, examples, drawings, and claims, and their previous and following description. However, before the present devices, systems, and/or methods are disclosed and described, it is to be understood that this invention is not limited to the specific devices, systems, and/or methods disclosed unless otherwise specified, and, as such, can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
The following description is provided as an enabling teaching of various aspects and examples of the invention. To this end, those skilled in the relevant art will recognize and appreciate that many changes can be made to the various aspects and examples described herein, while still obtaining the beneficial results of the devices and methods described herein. It will also be apparent that some of the desired benefits of the devices and methods herein can be obtained by selecting some of the features of the described examples without utilizing other features.
Accordingly, those who work in the art will recognize that many modifications and adaptations to the devices and methods herein are possible and can even be desirable in certain circumstances and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not in limitation thereof.
For clarity, it will be appreciated that this disclosure will focus on the treatment of functional mitral regurgitation, however it is contemplated that the heart valve leaflet replacement system and the associated methods can be used or otherwise configured to be used to treat other types of mitral regurgitation or to replace other diseased valves of the human heart, such as tricuspid valve, or could be used or otherwise configured to be used in other mammals suffering from valve deficiencies as well.
As used throughout, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a leaflet” can include two or more such leaflets unless the context indicates otherwise.
Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.
The word “or” as used herein means any one member of a particular list and also includes any combination of members of that list. Further, one should note that conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain aspects include, while other aspects do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more particular aspects or that one or more particular aspects necessarily include logic for deciding, with or without user input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular embodiment.
Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these cannot be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods.
The present methods and systems can be understood more readily by reference to the following detailed description of preferred embodiments.
Throughout the description, the terms “prosthetic valve” and “prosthesis” and “valve stent” and “heart valve leaflet replacement device” and “valve device” are used interchangeably and is contemplated as a heart valve replacement device described herein.
Referring to
In the mitral regurgitation diseased state, e.g., depicted in
The low-profile prosthetic hemi-valve devices, systems, and methods presented herein may be used to treat mitral regurgitation in patients with normal native mitral leaflets and chordae by filling the regurgitant orifice 9 during systole.
It is contemplated that the device has a major axis 13 and minor axis 14 at the neck portion of the frame, wherein the major axis 13 corresponds to the commissure-to-commissure anatomical direction and the minor axis 14 corresponds to the anterior-to-posterior anatomical direction of the mitral annulus. In one example, the upper portion of the frame 10 has a larger minor axis 14, i.e., greater than 5 mm larger, than the lower portion of the frame 11, and a similar or larger major axis 13 compared to that of the lower portion of the frame 11. The lower portion of the frame 11 is configured to be open. The upper portion of the frame can be configured in an open or closed shape.
The prosthetic leaflet 16 can be configured to be flexible and mobile throughout the cardiac cycle. During the systolic phase, the at least one prosthetic leaflet 16 extends to coapt with native anterior leaflets 1 by extending radially outwards from the lower portion of the frame to prevent leakage between the anterior coaptation surface 17 of the implant and the native anterior leaflet 1, while the native posterior leaflets 2 extend to coapt with the outer surface of the lower portion of the frame 11 to prevent leakage between the posterior coaptation surface 18 of the implant and the native posterior leaflet 2. During diastole, the at least one prosthetic leaflet 16 is configured to move towards the lower portion of the frame 11 to allow for blood to flow from the left atrium 8 to the left ventricle 4 between the anterior coaptation surface of the implant 17 and the native anterior leaflet 1. Additionally, the neck portion 12 can be configured with a posterior flow channel 19 that allows blood to flow from the left atrium to the left ventricle between the posterior coaptation surface of the implant 18 and the native posterior leaflet 2.
It is contemplated that the prosthetic leaflet 16 can be comprised of a thin, flexible material including human or animal tissues, polymer, or fabric.
It is contemplated the upper 10, lower 11, and neck portion 12 of the frame can be comprised of a metallic material such as one or more of Nitinol, cobalt chromium, or stainless steel, or a polymer material.
It is contemplated that the sealing skirt 15 can be comprised of a thin, flexible material including one or more of human or animal tissues, polymer, or fabric.
It is contemplated that the upper portion of the frame 10 can be configured to facilitate anchoring of the device on the native annulus 3. In operation, the upper portion 10 can be anchored to the native annulus 3, such that the lower portion 11 is suspended in the left ventricle 4 and is parallel to the blood flow. In one example for the treatment of mitral regurgitation, the lower portion of the frame 11 can be configured with a fish mouth-shape similar to the native coaptation line 6. The at least one prosthetic leaflet 16 can be configured as three distinct cusps similar to the native posterior leaflet as shown in
It is contemplated that the posterior coaptation surface 18 can be wrapped in or made by a soft, thin material such as human or animal tissues, polymer, or fabric to prevent the native posterior leaflet 2 from becoming damaged over time. It is further contemplated that the posterior coaptation surface 18 can be comprised of at least one prosthetic leaflet 16, or mobile surface, to coapt with the native posterior leaflet 2.
Referring again to
Referring again to
It is contemplated that the upper portion of the frame 10 can be configured as either a closed shape or an open shape. One knowledgeable in the art can appreciate that because the upper portion of the frame will sit on the left atrial 8 side of the annulus in operation, it should not impinge or hinder the native leaflet function. It is further contemplated that the upper portion of the frame 10 can be configured with a full or partial elliptical-, circular-, or D-shape to better conform to the annulus 3 and left atrium 8.
It is contemplated that the lower portion of the frame 11 could be configured with various other open shapes such as a partial elliptical-, circular-, or parabolic-shape to aid in the treatment of valvular regurgitation. For instance, it is contemplated that the lower portion of the frame 11 could be configured with a more V-shape to simulate the coaptation line between the anterior and posterior leaflets with the septal leaflet in the tricuspid valve to treat tricuspid regurgitation. It is also contemplated that the lower portion of the frame 11 could be configured with various heights along the long-axis direction. For instance, it is contemplated that the lower portion of the frame 11 could be configured with shorter vertical heights at the two sides of the open frame to avoid contact with the papillary muscle heads in the left ventricle.
It is contemplated that the lower portion of the frame 11 can be configured with a major axis 13 similar or slightly larger than that of the native annulus such that it is wide enough to allow for a native leaflet to fit inside the confines of the lower portion of the frame 11 to coapt with the prosthetic leaflet 16. Further, it is contemplated that the lower portion of the frame 11 can be configured with a minor axis 14 that is smaller than that of the native annulus such that the overall device footprint inside the left ventricle as well as the crimped profile is desirably low.
It can be appreciated by those skilled in the art, that it is desirable to have a device that can anchor well, reduce mitral regurgitation without negatively impacting the surrounding anatomical structures and functions, and be able to fit in a low-profile delivery catheter for improved patient safety. The upper portion 10 of the device presented in this disclosure has a large diameter for anchoring on a dilated mitral annulus 3, yet minimal material such that it can be easily crimped to a small diameter. The lower portion 11 of the device has more material, including a plurality of prosthetic leaflets 16, but a smaller size, particularly the minor axis 14, such that it can also be crimped to a small diameter.
It is contemplated that the low-profile prosthetic hemi-valve device can be configured with a plurality of posterior flow channels 19 of varying sizes and shapes or optionally without any posterior flow channel 19 such that there is only one blood flow channel through the mitral orifice, the anterior flow channel 22. The flexible and movable prosthetic leaflet 16 can be configured such that the anterior coaptation surface 17 moves substantially away from the native anterior leaflet 1 during diastole to allow ample flow from the left atrium 8 to the left ventricle 4.
It is contemplated that the frame can be configured with a plurality of diamond shaped cells 25 such that the frame can be selectively crimped and loaded into a small diameter catheter. In the preferred embodiment, the upper portion of the frame 10 can span the posterior annulus from the medial trigone to the lateral trigone in a “D-shape” designed to conform with the mitral annulus and left atrial wall 8. Further in this example, the lower portion of the frame can span the mitral valve coaptation line 6 from the medial commissure to the lateral commissure in a “fish-mouth” shape similar to the native mitral valve coaptation line 6. The exposed tips of the diamond cells in the frame can optionally be bent inwards radially to avoid interference with surrounding tissues including the left atrium 8, native posterior leaflet 2, chordae tendinae 5, and native anterior leaflet 1.
The upper portion of the frame 10 can optionally be configured with a plurality of eyelets for engaging an anchoring mechanism, a crimping mechanism, and/or a loading mechanism into a catheter for transcatheter delivery in a patient.
The lower portion of the frame 11 can optionally be configured with a plurality of eyelets to facilitate crimping and/or loading the crimped the device into a catheter for transcatheter delivery in a patient.
In an exemplary method, the low-profile prosthetic hemi-valve device can be guided and fixed into place on the annulus via a plurality of dual-guiding-fixation (DGF) members 26 shown in
Referring to
It should be emphasized that the above-described aspects are merely possible examples of implementation, merely set forth a clear understanding of the principles of the present disclosure. Many variations and modifications can be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure, and all possible claims to individual aspects or combinations of elements or steps are intended to be supported by the present disclosure. Moreover, although specific terms are employed herein, as well as in the claims which follow, they are used only in a generic and descriptive sense, and not for the purposes of limiting the described invention, nor the claims which follow.
The present application claims benefit of co-pending U.S. provisional application Ser. No. 63/425,650, filed Nov. 15, 2022, and is related to U.S. Publication Nos. 2021/0212824 and 2017/0258589, the entire disclosures of which are expressly incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 63425650 | Nov 2022 | US |
