ARTIFICIAL, FLEXIBLE VALVES AND METHODS OF FABRICATING AND SERIALLY EXPANDING THE SAME
One aspect of the invention provides and artificial, flexible valve indlucding: a stent defining a wall and a plurality of leaflets extending from the wall of the stent. The plurality of leaflets form a plurality of coaptation regions between two adjacent leaflets. The coaptation regions include extensions along a z-axis and adapted and are configured to form a releasable, but substantially complete seal when the leaflets are in a closed position. Another aspect of the invention provides an artificial, flexible valve including: a stent defining a wall and a plurality of leaflets extending from the wall of the stent. Each of the plurality of leaflets terminates in a commissure line. The commissure lines devi-ate from a hyperbola formed in the x-y plane by at least one deviation selected from the group consisting of: a deviation in the z-direction and one or more curves relative to the hyperbola.
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This application claims priority to U.S. Provisional Patent Application Ser. No. 61/989,820, filed May 7, 2014. The entire content of this application is hereby incorporated by reference herein.
BACKGROUND OF THE INVENTIONValves exist in the body (e.g., in the heart and the systemic veins) to allow unidirectional blood flow. A variety of congenital conditions, infectious diseases (e.g., rheumatic heart disease), endocarditis, and age-related impairments (e.g., senile stenosis) can necessitate implantation of an artificial valve.
SUMMARY OF THE INVENTIONOne aspect of the invention provides an artificial, flexible valve including: a stent defining a wall and a plurality of leaflets extending from the wall of the stent. The plurality of leaflets form a plurality of coaptation regions between two adjacent leaflets. The coaptation regions include extensions along a z-axis and adapted and are configured to form a releasable, but substantially complete seal when the leaflets are in a closed position.
This aspect of the invention can have a variety of embodiments. The extensions can have a length along the z-axis between about 1 mm and about 10 mm. The extensions can have a curved profile. The curved profile can lie in an x-y plane. The curved profile can be a variance in extension length along the z-axis.
The coaptation regions can have a substantially hyperbolic profile. Each of the plurality of leaflets can have a substantially elliptical leaflet-stent attachment line. The stent can be an expandable, cylindrical stent. The leaflets can be reinforced with one or more selected from the group consisting of: reinforcing materials and directional fibers. One or more selected from the group consisting of: coaptation regions and leaflet-stent attachment lines can be reinforced with one or more selected from the group consisting of: additional polymer thickness, reinforcing materials, and directional fibers.
Adjacent leaflets can be coupled to a wide post of the stent. The wide post can include one or more windows. The wide post can have a width between about 0.5 mm and about 3 mm.
The stent can include metal or plastic. The metal can be selected from the group consisting of: stainless steel, 316L stainless steel, cobalt-chromium alloys, and nickel-titanium alloys.
The leaflets can be formed from a first polymer. The first polymer can be selected from the group consisting of: polytetrafluoroethylene, polyethylene, polyurethane, silicone, and copolymers thereof.
The stent can be dip-coated in a second polymer. The second polymer can be selected from the group consisting of: polytetrafluoroethylene, polyethylene, polyurethane, silicone, and copolymers thereof. The leaflets can be coupled to the second polymer. The leaflets can be mechanically coupled to the second polymer. The leaflets can be chemically coupled to the second polymer. The leaflets can be coupled to the second polymer by one or more techniques selected from the group consisting of: gluing, chemical fusing, thermal fusing, sonic welding, stitching, and mechanical fastening.
A leaflet-stent attachment line for each of the plurality of leaflets can substantially approximate a frame of the stent. The leaflet-stent attachment line can lie within about 3 mm of the frame of the stent.
The stent can include one or more anchor points. The anchor points can contain a radio-opaque material.
The valve can be adapted and configured for replacement of one or more cardiac valves selected from the group consisting of: aortic, mitral, tricuspid, and pulmonary.
The valve can be adapted and configured for insertion in a subject's veins in order to treat venous insufficiency. The valve can be adapted and configured for serial expansion as the subject ages.
Another aspect of the invention provides an artificial, flexible valve including: a stent defining a wall and a plurality of leaflets extending from the wall of the stent. Each of the plurality of leaflets terminates in a commissure line. The commissure lines deviate from a hyperbola formed in the x-y plane by at least one deviation selected from the group consisting of: a deviation in the z-direction and one or more curves relative to the hyperbola.
This aspect of the invention can have a variety of embodiments. The leaflets can further include extensions beyond the commissure lines along a z-axis. The extensions can have a length along the z-axis between about 1 mm and about 10 mm. The extensions can have a curved profile. The curved profile can lie in an x-y plane. The curved profile can be a variance in extension length along the z-axis.
Each of the plurality of leaflets can have a substantially elliptical leaflet-stent attachment line. The stent can have an expandable, cylindrical stent. The leaflets can be reinforced with one or more selected from the group consisting of: reinforcing materials and directional fibers.
One or more selected from the group consisting of: coaptation regions and leaflet-stent attachment lines can be reinforced with one or more selected from the group consisting of:
additional polymer thickness, reinforcing materials, and directional fibers.
Adjacent leaflets can be coupled to a wide post of the stent. The wide post can include one or more windows. The wide post can have a width between about 0.5 mm and about 3 mm.
The stent can include metal or plastic. The metal can be selected from the group consisting of: stainless steel, 316L stainless steel, cobalt-chromium alloys, and nickel-titanium alloys.
The leaflets can be formed from a first polymer. The first polymer can be selected from the group consisting of: polytetrafluoroethylene, polyethylene, polyurethane, silicone, and copolymers thereof.
The stent can be dip-coated in a second polymer. The second polymer can be selected from the group consisting of: polytetrafluoroethylene, polyethylene, polyurethane, silicone, and copolymers thereof. The leaflets can be coupled to the second polymer. The leaflets can be mechanically coupled to the second polymer. The leaflets can be chemically coupled to the second polymer. The leaflets can be coupled to the second polymer by one or more techniques selected from the group consisting of: gluing, chemical fusing, thermal fusing, sonic welding, stitching, and mechanical fastening.
A leaflet-stent attachment line for each of the plurality of leaflets can substantially approximate a frame of the stent. The leaflet-stent attachment line can lie within about 3 mm of the frame of the stent.
The stent can include one or more anchor points. The anchor points can contain a radio-opaque material.
The valve can be adapted and configured for replacement of one or more cardiac valves selected from the group consisting of: aortic, mitral, tricuspid, and pulmonary.
The valve can be adapted and configured for insertion in a subject's veins in order to treat venous insufficiency. The valve can be adapted and configured for serial expansion as the subject ages.
Another aspect of the invention provides an artificial, flexible valve including: an expandable, cylindrical stent defining a wall and a plurality of leaflets extending from the wall of the stent. Adjacent leaflets can be coupled to a relatively wide post of the stent.
The leaflets can further include extensions beyond the commissure lines along a z-axis. The extensions can have a length along the z-axis between about 1 mm and about 10 mm. The extensions can have a curved profile. The curved profile can lie in an x-y plane. The curved profile can be a variance in extension length along the z-axis.
The coaptation regions can have a substantially hyperbolic profile. Each of the plurality of leaflets can have a substantially elliptical leaflet-stent attachment line. The leaflets can be reinforced with one or more selected from the group consisting of: reinforcing materials and directional fibers.
One or more selected from the group consisting of: coaptation regions and leaflet-stent attachment lines can be reinforced with one or more selected from the group consisting of: additional polymer thickness, reinforcing materials, and directional fibers.
The relatively wide post can include one or more windows. The relatively wide post can have a width between about 0.5 mm and about 3 mm.
The stent can include metal or plastic. The metal can be selected from the group consisting of: stainless steel, 316L stainless steel, cobalt-chromium alloys, and nickel-titanium alloys.
The leaflets can be formed from a first polymer. The first polymer can be selected from the group consisting of: polytetrafluoroethylene, polyethylene, polyurethane, silicone, and copolymers thereof.
The stent can be dip-coated in a second polymer. The second polymer can be selected from the group consisting of: polytetrafluoroethylene, polyethylene, polyurethane, silicone, and copolymers thereof. The leaflets can be coupled to the second polymer. The leaflets can be mechanically coupled to the second polymer. The leaflets can be chemically coupled to the second polymer. The leaflets can be coupled to the second polymer by one or more techniques selected from the group consisting of: gluing, chemical fusing, thermal fusing, sonic welding, stitching, and mechanical fastening.
A leaflet-stent attachment line for each of the plurality of leaflets can substantially approximate a frame of the stent. The leaflet-stent attachment line can lie within about 3 mm of the frame of the stent.
The stent can include one or more anchor points. The anchor points can contain a radio-opaque material.
The valve can be adapted and configured for replacement of one or more cardiac valves selected from the group consisting of: aortic, mitral, tricuspid, and pulmonary. The valve can be adapted and configured for insertion in a subject's veins in order to treat venous insufficiency. The valve can be adapted and configured for serial expansion as the subject ages. The valve may not contain any animal-derived materials.
Another aspect of the invention provides a mandrel including: a cylindrical profile and a plurality of recesses adapted and configured to define a plurality of leaflets forming a plurality of coaptation regions between two adjacent leaflets. The coaptation regions can include extensions along a z-axis and be adapted and configured to form a releasable, but substantially complete seal when the leaflets are in a closed position.
This aspect of the invention can have a variety of embodiments. The mandrel can include one more cutting guides located between the plurality of recesses. The mandrel can include one or more heating elements.
Another aspect of the invention provides a mandrel including: a cylindrical profile and a plurality of recesses adapted and configured to define a plurality of leaflets. Each of the plurality of leaflets terminate in a commissure line. The commissure lines deviate from a hyperbola formed in the x-y plane by at least one deviation selected from the group consisting of: a deviation in the z-direction and one or more curves relative to the hyperbola.
This aspect of the invention can have a variety of embodiments. The mandrel can include one more cutting guides located between the plurality of recesses. The mandrel can include one or more heating elements.
Another aspect of the invention provides a method for fabricating an artificial, flexible valve. The method includes: dip coating a cylindrical mandrel having a plurality of recesses each approximating a profile of a leaflet and coupling the leaflets to an inner wall of a stent.
This aspect of the invention can have a variety of embodiments. The method can further include dip coating the stent prior to coupling the leaflets to the inner wall of the stent. The stent and the mandrel can have larger diameters than a target location for the valve. The method can further include separating adjacent leaflets from each other.
For a fuller understanding of the nature and desired objects of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawing figures wherein like reference characters denote corresponding parts throughout the several views and wherein:
The instant invention is most clearly understood with reference to the following definitions.
As used herein, the singular form “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from context, all numerical values provided herein are modified by the term about.
As used in the specification and claims, the terms “comprises,” “comprising,” “containing,” “having,” and the like can have the meaning ascribed to them in U.S. patent law and can mean “includes,” “including,” and the like.
Unless specifically stated or obvious from context, the term “or,” as used herein, is understood to be inclusive.
Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 50 is understood to include any number, combination of numbers, or sub-range from the group consisting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 (as well as fractions thereof unless the context clearly dictates otherwise).
DETAILED DESCRIPTION OF THE INVENTIONAspects of the invention provide a novel platform that allows development of polymeric valves of any size and shape. Aspects of the invention can be applied to valves designed for surgical implantation (e.g., through a sternotomy or thoracotomy) or valves designed for percutaneous, transcatheter implantation. Additionally, embodiments of the invention allow for possible percutaneous replacement of a dysfunctional valve, whether in adults or in small children. In addition, if implanted in a child, embodiments of the invention allow the valve to be serially expanded to accompany the child's growth.
Cardiac ApplicationsMultiple types of congenital heart defects require heart valve replacement surgery in infancy or childhood. In adults, the most commonly replaced valves are aortic and mitral, whereas in children, the pulmonary valve is the most commonly replaced valve. Heart valves are currently replaced using tissue valves (homograft or xenograft) or mechanical metal valves, each having their shortcomings. Homograft valves are in short supply, particularly in sizes suitable for use in children, and biologic tissue-based valves (whether bovine, porcine, or homograft) tend to induce an immunologic reaction which leads to failure of these valves. Mechanical valves generally require anticoagulation, and are almost never used in the pulmonary position due to an increased risk of thrombosis.
Furthermore, none of the surgically implanted valves can adapt to growing patients. The rapid growth of pediatric patients leads them to outgrow their implanted valves within a few years and induces a cycle of frequent surgical valve replacements during childhood. Aspects of the invention provide valves having improved biocompatibility, durability, and hemodynamic performance and would reduce the frequency of recurrent open heart surgeries for valve replacement.
Venous ApplicationsAdditionally, aspects of the invention can be used for venous valve replacement in patients having venous disease such as chronic venous insufficiency (leading to leg swelling). Because the polymer leaflets can be made extremely thin, the valves can even open under extremely low venous pressure gradients.
Artificial, Flexible ValvesReferring now to
The valve 100 will now be described in the context of its components and methods of fabrication.
StentsReferring now to
Stent 102 can be completely enveloped by a polymer dip coating. Stent 102 and/or wall 104 can also be fabricated from a biocompatible material.
The stent 102 can be manufactured by laser cutting or wire forming. To increase bonding strength between metal and polymer, roughness of stent surface can be controlled. Some or all open cells 204, 206 of the stent can be covered as the bare 102 stent is dipped into the polymer solution.
The components of stent 102 can have a variety of dimensions that can be selected to achieve a desired flexibility, rigidity, resilience, and the like. For example, the thickness and width of components of the stent 102 can be between about 0.1 mm and about 2 mm.
As discussed above, stent 102 can include one or more vertical posts 110a-110c to enhance bonding with leaflets 106.
Stent 102 can include a plurality of vertical posts 110 that can serve a variety of functions. Some vertical posts 110 can include additional structure and are referred to herein as wide posts 112. Wide posts 112 are preferably located at leaflet joints where two leaflets 106 meet. For example, in a valve 100 having a three leaflets 106, wide posts 112 can be positioned at 120° intervals within cylindrical stent 102.
Wide posts 112 provide mechanical support to leaflets and prevent or substantially limit inward deformation of wall 104 due to tensile forces applied to leaflets 106 transferred to wall 104. Without being bound by theory, it is believed that the wide posts 112 provide increased strength and resiliency due to formation of polymer wall 104 through windows 206 and around wide posts 112, thus providing cohesive holding of the polymer to itself around the stent 102 instead of relying solely on adhesive bonding of the polymer wall 104 to the stent 102.
Wide posts 112 advantageously allow for relaxed tolerances in positioning leaflets 106 relative to wide posts 112. For example, window 208 can have a width of between about 0.5 mm and about 3 min (e.g., about 1 mm) and a height of between about 1 mm and about 10 mm (e.g., about 5 mm).
A variety of additional wide post geometries are depicts in
Referring now to
Referring now to
In one embodiments depicted in
Leaflets 106 can be formed using a variety of techniques including dip coating, 3D-printing (also known as additive manufacturing), molding, and the like.
Referring now to
The mandrel 900 for the leaflets 106 can have novel features, including edges representing the leaflet attachment points that are mathematically defined and leaflet tips that are extended in order to increase the coaptation length of the leaflets. The mandrel 900 can be dimensioned to produce leaflets 106 having different regional thickness and supplementary materials such as directional fibers or reinforcing particles inserted between layers or mixed into the polymer solution in order to increase durability. For example, polymer interaction with particles on the nanoscale or microscale can greatly improve the physical properties or tear resistance of the polymer leaflets 106.
Mandrel 900 can be designed to have a complementary geometry to the desired leaflet shape and permits easier viewing of leaflet geometry. Although mandrel 900 is utilized to describe the geometry of the leaflet 106, it should be recognized that the upstream surface of the resulting leaflets will have this geometry when formed by dip coating and that the complementary geometry of the leaflet(s) 106 can be produced using techniques other than dip coating. Mandrel 900 is preferably cylindrical and can have an outer profile substantially approximating an inner profile of stent 102. Mandrel 900 can define a plurality of pockets 902 that each define a leaflet 106 as it hangs from wall 104 via attachment line 108. Each leaflet 106 terminates in a commissure line 904 often, but not necessarily lying in a plane at the point where the elliptical or parabolic curve ends and where the leaflet often contacts the other leaflets. A substantially vertical coaptation region 906 can extend beyond the commissure line 904 to an extended commissure line 912 for improved sealing as will be discussed herein.
Referring now to
Referring now to
As seen in
Referring now to
The zone of coaptation is affected by the pressure placed upon the closed valve 100. The higher the pressure, the more downward tension is placed on the leaflets 106, possibly leading to a failure of coaptation with consequent regurgitation. Proper coaptation also allows the leaflets 106 to support each other, so there is less stress placed on any individual leaflet 106. Another benefit of enhancing height of the coaptation zone is that this allows the valve 100 to be re-dilated to a larger diameter late after implantation (such as to accommodate growth of a pediatric patient), while still maintaining competence of the valve 100.
Options for enhancing the height of the coaptation zone include creating excess length of the leaflet free edges, so that the free edge length is greater than twice the radius of the stent or mandrel depicted in
Referring now to
Referring now to
Referring now to
Referring now to
In order to increase tear-resistance of the leaflets 106 and enhance bonding strength between leaflets 106 and stent 102, the thickness of the leaflets 106 can be controlled regionally. Because the most common failure points are at the outer edges of the leaflets 106 (such as commissure line 904 or extended commissure line 912 and leaflet-stent attachment line 108), increased thickness at outer areas of the leaflets 106 can improve the strength and durability. Also, if local areas are expected to have concentrated stress, the areas can be locally reinforced (e.g., made thicker than other areas). The thickness can be smoothly increased. The width of thickened area along leaflet-stent attachment line 108 can be large enough to cover the glued area for bonding the leaflets 106 and the covered stent 102. In some embodiments, the thickness of thickened areas of the leaflets is between about 0.1 mm and about 1 mm.
Multiple dippings can be performed to produce leaflets with a desired thickness. In some embodiments, the thickness of the leaflets is between about 0.01 mm and about 0.2 mm.
Different reinforcing materials such as strips, fibers and particles can be placed between the layers, or directly mixed into the polymer solution. The inserted material(s) can prevent tearing and reduce propagation of the tear if it occurs. The materials can have directional properties and can be layered onto, or embedded into, the leaflets in an optimal direction to prevent or limit tears.
Referring now to
After dipping the mandrel 900 into the polymer solution, the coated polymer dries in order to form the leaflet(s) 106. Because the formed leaflets 106 are connected, they need to be separated from each other. These can be cut by a sharp cutter (e.g., a knife, a scalpel, a razor blade, a utility knife, and the like), a heated iron, a laser, a rotary tool, and the like. A guide on the top surface of the mandrel for cutting provides a clear, easy, and safe cutting path. The guide can be grooved/concave or convex. Also, the commissure edges of the mandrel can be sharp like a blade to facilitate leaflet separation and to improve on the quality of the cut edges.
Referring now to
The stent-mounted valve 100 can be implanted with smaller diameter than its manufactured diameter for reducing leakage and improving durability.
Methods of Fabricating ValvesReferring now to
In some embodiments, the stent 102 can be first coated with a polymer such as PEEK or other metal surface modifier prior to further dip coating of the stent 102 in another polymer in order to improve adhesion of the leaflet polymer 106 to the metal stent 102.
The bare mandrel 900 can optionally be coated with a release agent to promote separation of the polymer leaflets from the mandrel 900.
Both the bare stent 102 and the mandrel 900 are dip coated separately in a polymer, which may be the same or different for the bare stent 102 and the mandrel 900.
The leaflets 106 formed on the mandrel 900 can be removed prior to introduction to the coated stent. Alternatively, the coated mandrel 900 can be introduced into the coated stent, the leaflets 106 can be bonded to the coated stent, and the mandrel 900 can be then be removed to leave the assembled valve 100.
Leaflets 106 can be bonded to the dip-coated stent using a variety of techniques including gluing, chemical fusing (i.e., dissolving the polymers) thermal fusing, sonic welding, stitching, mechanical fastening, and the like. For example, the same polymer solution used to coat either bare stent 102 and/or mandrel 900 can be applied to bond the leaflets 106 to the dip-coated stent.
Although separate fabrication of the polymer-coated stent and the leaflets 106 are currently preferred as a means of avoiding or minimizing air bubbles, the entire valve could be formed in a single dip coating (or series of dip coatings) through use of production-grade manufacturing techniques and other optimizations.
Although dipcoating was successfully used to fabricate prototypes of the valves described herein, any other manufacturing technique capable of producing flexible leaflets can be utilized. Exemplary techniques include injection molding and additive manufacturing or 3D printing. Referring now to
As can be seen in
Referring now to
Polymers
The leaflets 106 can be formed from the same or different polymer with which the stent 102 is coated to form wall 104. For example, the leaflets 106 can be formed from polymers such as polyethylene, polyurethane, silicone, and the like. Wall 104 can be formed from polyethylene, polyurethane, silicone, and the like.
Supplementary materials such as directional fibers can mixed into the polymer solution or applied to the leaflets between coatings in order to increase durability
The selected polymer can be dissolved by a solvent such as tetrahydrofuran or dimethylacetamide. The thickness of the coated polymer can be controlled as a function of the density of the polymer solution and total number of dippings. When the polymer becomes dry after dipping, the coated stent and mandrel can be placed horizontally and axially rotated in order to produce a constant thickness and prevent the polymer from dripping.
Implantation of ValvesReferring now to
In step S1802, the valve is placed over an expander and within a sheath. Various surgical expanders and access devices exist in the cardiac surgery field. For example, a balloon catheter could be introduced into a patient's femoral artery and guided to the location of the implanted valve (e.g., within the patient's heart or systemic veins).
In step S1804, the sheath (containing the valve and the expander) is introduced into a vessel of the subject.
In step S1806, the valve and the expander are advanced from the sheath and positioned in the desired location.
In step S1808, the desired positioning can be verified using various imaging techniques such as fiber optics, ultrasound, X-ray, and the like.
In step S1810, the expander is actuated within the valve to expand the valve to form a press fit against the vessel in which the valve is implanted. For example, a balloon catheter can be expanded by introducing gas or a liquid into the balloon.
In step S1812, the desired positioning and expansion can be verified using various imaging techniques such as fiber optics, ultrasound, X-ray, and the like.
In step S1814, the expander and sheath can be retracted according to standard surgical techniques.
Expansion of Implanted ValvesReferring now to
In step S1902, an expander is introduced into the implanted valve.
In step S1904, the expander is actuated within the implanted valve to increase the diameter of the implanted valve.
In step S1906, the desired expansion can be verified using various imaging techniques. In step S1908, the expander can be retracted according to standard surgical techniques.
Surgically-Implanted ValvesAlthough embodiments of the invention are described and depicted in the context of percutaneous, transcatheter valves having expandable, cylindrical stents, embodiments of the invention described herein can be applied to surgically-implanted valves that generally include anchors having fixed-diameter anchors supporting a plurality of leaflets (e.g., the CARPENTIER-EDWARDS™ series of valves available from Edwards Lifesciences Corporation of Irvine, Calif.). In such embodiments, the anchor replaces the expandable, cylindrical stents described herein.
EQUIVALENTSAlthough preferred embodiments of the invention have been described using specific terms, such description is for illustrative purposes only, and it is to be understood that changes and variations may be made without departing from the spirit or scope of the following claims.
INCORPORATION BY REFERENCEThe entire contents of all patents, published patent applications, and other references cited herein are hereby expressly incorporated herein in their entireties by reference.
Claims
1-100. (canceled)
101. An artificial valve, comprising:
- an expandable frame configured to be implanted within a patient, the expandable frame having a maximum radial extent when the expandable frame is in a fully-expanded configuration in which the valve is in a maximum working condition; and
- a plurality of leaflets disposed within and coupled to the frame, each leaflet from the plurality of leaflets extending from the frame and terminating at a free edge, each free edge having a length that is greater than the maximum radial extent of the expandable frame when the expandable frame is in its fully-expanded configuration.
102. The artificial valve of claim 101, wherein a first leaflet from the plurality of leaflets is coupled to a first portion of the frame and a second portion of the frame, a distance along the free edge of the first leaflet between the first portion of the frame and the second portion of the frame being greater than an are distance along the frame between the first portion and the second portion.
103. The artificial valve of claim 101, wherein the expandable frame has a first end, a second end, and a longitudinal z-axis defined therebetween,
- the plurality of leaflets forming a coaptation region having a maximum radial extent in which the leaflets (1) coapt sufficiently to prevent fluid flow along the longitudinal z-axis in a first direction and through the coaptation region, and (2) allow fluid flow along the longitudinal z-axis in a second direction opposite the first direction,
- the coaptation region having a radial extent less than the maximum radial extent when the frame is in a partially-expanded configuration such that the plurality of leaflets coapt sufficiently to prevent fluid flow along the longitudinal z-axis in the first direction and through the coaptation region, and (2) allow fluid flow along the longitudinal z-axis in the second direction.
104. The artificial valve of claim 101, wherein each free edge forms a portion of the coaptation region and the leaflet free edges collectively provide a tortuous path for fluid flow to prevent fluid flow in the predefined direction.
105. The artificial valve of claim 101, wherein each leaflet has a variable thickness in which its thickness is reduced from its attachment to the expandable frame towards its free edge.
106. The artificial valve of claim 101, wherein the free edge of each leaflet varies along a longitudinal z-axis of the expandable frame when the expandable frame is in the fully-expanded configuration.
107. The artificial valve of claim 106, wherein the longitudinal z-axis of the expandable frame is defined between a first end of the expandable frame and a second end of the expandable frame, the plurality of leaflets being configured to allow fluid flow from the first end to the second end and restrict fluid flow from the second end to the first end.
108. The artificial valve of claim 101, wherein the plurality of leaflets are formed of polymer.
109. The artificial valve of claim 101, wherein each leaflet from the plurality of leaflets is coupled to the frame along a leaflet attachment line, the leaflet attachment line including a conic portion and a linear portion extending from a point at which the conic portion terminates to the free edge of the leaflet.
110. The artificial valve of claim 101, wherein the maximum working condition is a condition in which the expandable frame is expanded to its largest possible diameter that allows sufficient coaptation between the plurality of leaflets.
111. An artificial valve, comprising:
- an expandable frame configured to be implanted within a patient, the expandable frame having a maximum radial extent when the expandable frame is in a fully-expanded configuration in which the valve is in a maximum working condition; and
- a plurality of leaflets disposed within and coupled to the frame, each leaflet from the plurality of leaflets extending from the frame and terminating at a free edge, each free edge varies along a longitudinal z-axis of the expandable frame when the expandable frame is in its fully-expanded configuration.
112. The artificial valve of claim 111, wherein the longitudinal z-axis of the expandable frame is defined between a first end of the expandable frame and a second end of the expandable frame, the plurality of leaflets being configured to allow fluid flow from the first end to the second end and restrict fluid flow from the second end to the first end.
113. The artificial valve of claim 111, wherein a first leaflet from the plurality of leaflets is coupled to a first portion of the frame and a second portion of the frame, a distance along the free edge of the first leaflet between the first portion of the frame and the second portion of the frame being greater than an are distance along the frame between the first portion and the second portion.
114. A mandrel, comprising:
- a cylindrical profile having a plurality of recesses configured to define a plurality of valve leaflets,
- the plurality of recesses each (1) extending from a valve attachment line and (2) terminating at a commissure line, each commissure line having a length greater than a diameter of the cylindrical profile.
115. The mandrel of claim 114, wherein:
- each commissure line varies along a longitudinal z-axis of the cylindrical profile.
116. The mandrel of claim 114, wherein each commissure line is a first commissure line,
- each valve attachment line being curved until reaching a second commissure line that is defined between the attachment line and the first commissure line, a coaptation region being defined by and linearly extending between the first commissure line and the second commissure line.
117. The mandrel of claim 114, wherein each valve attachment line includes a conic portion and a linear portion that extends from a point at which the conic portion terminates to the commissure line.
118. The mandrel of claim 114, wherein the commissure line extends from the linear portion towards a center of the cylindrical profile, the commissure line varying in height.
119. The mandrel of claim 114, wherein the commissure line extends from the linear portion towards a center of the cylindrical profile, the commissure line varying along a longitudinal z-axis of the cylindrical profile.
120. A frame for an artificial valve, comprising: the expandable cylindrical body being formed by a plurality of posts extending substantially parallel to and circumferentially about the longitudinal z-axis, the plurality of posts including a first set of posts having a first width and a second set of posts having a second width that is greater than the first width, the first set of posts defining a plurality of open cells therebetween that are variable in shape during expansion of the expandable cylindrical body, each post from the second set of posts being disposed at a junction between and coupled to two valve leaflets from the plurality of valve leaflets.
- an expandable cylindrical body having a first end, a second end, and a longitudinal z-axis extending therebetween; and
- a plurality of valve leaflets,
121. The frame of claim 120, wherein each post from the second set of posts defines one or more windows configured to have a fixed shape during expansion of the expandable cylindrical body.
122. The frame of claim 121, wherein the second set of posts includes polymer within its one or more windows, each post from the second set of posts being coupled to the two valve leaflets via the polymer.
123. The frame of claim 120, wherein the plurality of open cells are covered.
124. The frame of claim 120, wherein the plurality of open cells are coated with a polymer.
125. The frame of claim 120, wherein the plurality of windows have a width of about 0.5 mm to about 3 mm, and a height of about 1 mm to about 10 mm.
126. The frame of claim 121, wherein the one or more windows are substantially rectangular.
127. The frame of claim 120, wherein the second set of posts consists of three posts each of which are circumferentially positioned at 120 degree intervals among the expandable cylindrical body, the plurality of valve leaflets consisting of three valve leaflets.
128. The frame of claim 120, wherein the plurality of valve leaflets are coupled to the second set of posts via at least one of a chemical coupling technique, chemical fusing, thermal fusing, or sonic welding.
129. The frame of claim 128, wherein the plurality of valve leaflets are formed of a polymer.
130. The frame of claim 120, wherein the entire external surface of the expandable cylindrical body is coated with a polymer.
Type: Application
Filed: Sep 6, 2019
Publication Date: Jan 2, 2020
Applicants: Baylor College of Medicine (Houston, TX), William Marsh Rice University (Houston, TX)
Inventors: Henri JUSTINO (Houston, TX), Daniel HARRINGTON (Houston, TX), Kwonsoo CHUN (Katy, TX)
Application Number: 16/563,229