KR20230129381A - Systems, devices and methods for folded unibody heart valve stents - Google Patents

Abstract

Prosthetic heart valves include unibody, folded, double-walled stents having a stent cover and leaflet valves attached to the internal lumen of the stent. The heart valve is provided by guide openings or structures fixed along the distal end of the delivery system that independently allow control of expansion of the distal and proximal ends of the outer wall of the stent, and expansion of the inner wall simultaneously or separately from expansion of the outer wall. It is delivered using a provided multi-pulley, suture-based stent restraint assembly.

Description

Systems, devices and methods for folded unibody heart valve stents

This patent application relates generally to the treatment of valvular disease, and more specifically to methods and devices for minimally invasive mitral valve replacement.

Heart valve disease has a global prevalence of 2 to 3% and is increasing in prevalence in aging populations, placing a significant burden on patients and healthcare systems. Valvular disease can result from a variety of etiologies, including autoimmune, infectious, and degenerative causes. The epidemiology of valvular disease also varies depending on the valve affected, and although rheumatic heart disease is the cause of primary mitral regurgitation and mitral stenosis worldwide, secondary mitral valve disease due to left ventricular dysfunction is more common in developed countries.

Current clinical guidelines by the American Heart Association and American College of Cardiology indicate that although surgical repair and valve replacement remain the mainstay of mitral valve therapy for many, transcatheter mitral valve repair is not recommended for certain patient populations. It is recommended for In the 2017 Focused Update and 2014 Guidelines for the Management of Patients with Valvular Disease, AHA/ACC recommended percutaneous mitral balloon junction incision for severe mitral stenosis and severe primary mitral regurgitation with a reasonable life expectancy who are candidates for non-surgery due to complications. Transcatheter mitral valve repair was recommended for patients with certain severe symptoms.

The further growth of transcatheter mitral valve therapy is challenged by difficulties posed by mitral valve anatomy and physiology compared to the more established transcatheter aortic valve therapy. For example, some mitral valve replacement therapies in development make a compromise between the sealing and anchoring properties of the external portion of the replacement valve and the support of the leaflet valve. Other therapies attempt to address this problem with two-part prosthetic valve structures, but these therapies have high delivery failure rates or may be too bulky for transcatheter delivery.

To address these issues, embodiments described herein relate to a prosthetic heart valve comprising a unibody, folded, double-walled stent with a stent cover and leaflet valves attached to the internal lumen of the stent. The double wall stent structure isolates or reduces the influence of the geometry of the retaining structure on the geometry of the valve support. This includes the effects of non-circular valve annulus geometry as well as external forces acting through the valve annulus during the cardiac cycle. The double-walled stent structure also allows the valve support to have a different size and shape than the external ring support without conforming to the natural anatomy. This may reduce the risk of outflow track obstruction and/or damage due to ventricular contraction by allowing the outer wall to have a shorter longitudinal length than the inner wall supporting the valve leaflets. Unibody designs can also allow for greater structural integrity by reducing the complexity associated with force concentration between support components that are bonded, welded, or mechanically connected and/or attached in place.

In some variations, this allows contraction of the expandable valve to a size of less than 29F, such as less than 10 mm, or 24F to 29F, or 8 mm to 10 mm. Heart valves can be delivered using a catheter or multiple pulley, suture-based stent restraint assembly of the delivery tool. Guide openings or structures secured along the distal end of the delivery system independently allow expansion of the distal and proximal ends of the stent outer wall via sutures passing through the openings. Control of interior wall expansion can occur simultaneously with expansion of the exterior wall or independently. The double-wall unibody design reduces complexity for valves with multi-component construction, while still providing adequate foldability for transcatheter delivery and separates the geometry of the valve support from the retention structure.

In one example, a prosthetic heart valve is provided that includes a folded double-walled unibody stent frame. The stent frame has a collapsed configuration and an expanded configuration, an outer wall comprising an open enlarged diameter region, an intermediate reduced diameter region, and a closed enlarged diameter region, a tubular inner wall with a central lumen, and a transition wall between the outer wall and the inner wall. and wherein the artificial leaflet valve is positioned in the central lumen of the internal wall. The unibody stent frame may further include a first fold between the closed enlarged diameter region and the tubular interior wall. The unibody stent frame may further include a second fold between the closed and open enlarged regions. The exterior wall may enclose at least 70% of the interior wall in an expanded configuration. The exterior wall and transition wall may completely surround the interior wall in the folded configuration. The tubular inner wall may include a non-shortened region surrounding the prosthetic valve when transitioning from a folded configuration to an expanded configuration. The interior wall may be a non-uniaxial interior wall, and the exterior wall may be a uniaxial exterior wall. The radius of curvature at the first folded portion may be smaller than the radius of curvature at the second folded portion. The unibody stent frame may further include a plurality of longitudinal struts, each longitudinal strut being positioned sequentially along the inner wall, transition wall and outer wall. In some variations, for at least one or both of the plurality of longitudinal struts, successive segments of longitudinal struts located on the interior wall, transition wall, and exterior wall are coplanar. Continuous segments of the longitudinal struts may also be coplanar with the central longitudinal axis of the unibody stent frame. The plurality of longitudinal struts may be formed integrally with the plurality of circumferential struts. In some examples, at least three circumferential struts are located in the exterior wall. The valve may also further include a stent covering, wherein the stent covering comprises a first region on the outer surface of the outer wall, a second region on the open end of the outer wall, a third region on the outer surface of the transition wall, an inner surface of the inner wall. a fourth region on the open end of the inner wall, a fifth region on the outer surface of the inner wall, a seventh region on the inner surface of the outer wall, and a third region between the inner surface of the outer wall and the outer surface of the inner wall. Includes 8 area parts. Portions of the first, second, third, and fourth regions may comprise a first textile structure, portions of the fourth and fifth regions may comprise a second textile structure, and portions of the sixth, seventh, and third regions may comprise a second textile structure. and the eighth region may include a third textile structure. The first fabric structure and the third fabric structure can include a first fabric material, and the second fabric structure can include a second fabric material that is different from the first fabric material. The first textile material may be less permeable and thinner than the second textile material. The plurality of longitudinal struts and the plurality of circumferential struts may include a segmented annular cross-sectional shape, wherein the orientation of the segmented annular cross-sectional shape in the interior wall is opposite to the orientation of the segmented annular cross-sectional shape in the exterior wall. .

In another embodiment, a prosthetic heart valve is provided, the prosthetic heart valve comprising a folded double-walled unibody stent frame, the stent frame comprising an open enlarged diameter region, an intermediate reduced diameter region, and a closed enlarged diameter region. A unibody stent frame comprising an outer wall, a cylindrical inner wall having a central lumen, and a transition surface between the outer and inner walls; and a prosthetic leaflet valve located in the central lumen of the internal wall. The unibody stent frame may further include a plurality of longitudinal struts, each longitudinal strut comprising a transition surface segment and a longitudinal inner wall segment and a continuous longitudinal outer wall segment. For at least one of the plurality of longitudinal struts, the longitudinal outer wall segment, transition surface segment and longitudinal inner wall segment may be continuously coplanar. The unibody stent frame can include a central longitudinal axis, wherein at least one of the plurality of longitudinal struts, each of which is a continuously coplanar longitudinal outer wall segment, a transition surface segment, and a longitudinal inner wall segment, also has a central longitudinal axis. is the same plane as In some examples, adjacent longitudinal struts of the plurality of longitudinal struts may form a plurality of chevron struts in the circumferential direction. Each of the plurality of longitudinal struts may include a longitudinal exterior wall segment, a transition surface segment, and continuously coplanar longitudinal interior wall segments. The unibody stent frame may have a relatively smaller radius of curvature at the transition connection between the outer wall and the transition surface and a relatively larger radius of curvature at the transition connection between the transition surface and the interior wall.

In another example, a stent can be provided that includes a unibody double wall expandable stent frame having a central opening and a central axis and including an expanded configuration and a contracted configuration. The stent frame may be a folded stent frame. The folded stent frame may be an everted or inverted stent frame. The stent frame includes a circumferential inner wall, including an open end, a transition end, and inner and outer surfaces between the ends, a circumferential inner wall, and a circumferential outer wall, including an open end, a transition end, and an inner and outer surface between the ends. It may further include a circumferential outer wall, comprising inner and outer surfaces, and a transition wall between transition ends of the inner wall and the outer wall. The inner wall of the stent frame may be non-shortened in the expanded configuration compared to the contracted configuration. The stent frame may further include an annular cavity between the inner and outer walls, the cavity comprising an annular closed end at the transition wall and an annular open end between the open ends of the inner and outer walls. The exterior wall may include an intermediate region having a reduced cross-sectional area in an expanded configuration compared to the cross-sectional area at the end regions of the exterior wall. The interior wall may comprise a cylindrical or frustoconical shape. In a collapsed configuration, the interior surface of the exterior wall may be spaced closer to the exterior surface of the interior wall, and in an expanded configuration, the interior surface of the exterior wall may be spaced longitudinally distally from the exterior surface of the interior wall compared to the contracted configuration. is separated from The stent frame may further include a first delivery configuration, where transition ends of the inner and outer walls are in a partially expanded configuration and open ends of the inner and outer walls are in a partially retracted configuration. The transition wall may have a transverse orientation about the central axis in the expanded configuration and a longitudinal orientation about the central longitudinal axis and a radially outward position relative to the inner wall in the contracted configuration. The stent frame may have a smaller radius of curvature at the transitional end of the outer wall compared to a larger radius of curvature at the transitional end of the inner wall, or a smaller radius of curvature at the transitional end of the outer wall compared to the open end of the outer wall and the transitional end. It can have a larger radius of curvature in between. The stent frame includes a plurality of longitudinal struts, each longitudinal strut including a longitudinal outer wall segment adjacent and radially aligned with a longitudinal inner wall segment through a transition wall segment. Adjacent longitudinal struts of the plurality of longitudinal struts may be spaced circumferentially through the plurality of chevron struts. Each chevron strut of the plurality of chevron struts may include a first and a second leg, each leg having a base end formed integrally with one of the adjacent longitudinal struts, and a distal end formed integrally with a distal end of the other leg. Includes the ends. The integrally formed distal ends of the first and second legs may include a hairpin configuration. At least some of the plurality of chevron struts may be oriented in a tangential plane defined by adjacent longitudinal strut segments with which each chevron strut is integrally formed. At least one of the plurality of chevron struts may be oriented radially out-of-plane from the tangential plane. The out-of-plane chevron struts may be formed integrally with the longitudinal struts adjacent the outer wall, with the hairpin configuration projecting into the reduced diameter region of the stent frame and directed toward the transitional end of the outer wall. In some variations, it may further include a leaflet valve sewn to the inner wall. The plurality of chevron struts may include a plurality of wavy circumferential struts. The stent has a first fabric covering comprising an outer cuff covering a portion of the outer surface of the outer wall, an open end of the outer wall, and a portion of the inner surface of the outer wall, and a transition wall. and a second fabric covering covering a portion of the interior surface of the interior wall. The open end of the interior wall may be offset from the open end of the exterior wall along the central longitudinal axis.

In another embodiment, a prosthetic heart valve is provided, the prosthetic heart valve comprising a unibody stent frame having a folded double-walled hourglass shape, the stent frame having an outer wall having an hourglass shape, the hourglass shape having an open enlarged opening. A unibody stent frame comprising an outer wall comprising a diameter region, an intermediate reduced diameter region, and a closed enlarged diameter region, a non-shortened tubular inner wall having a central lumen, and a transition wall between the outer wall and the inner wall. , and a prosthetic leaflet valve located in the central lumen of the internal wall.

In another example, a method for using a heart valve delivery system is provided, the method comprising: inserting a delivery catheter through a central opening of a valve and a unibody folded double-walled valve frame; attaching a first retention assembly to the valve frame; releasably attaching the second retention assembly to the exterior wall of the valve frame, tensioning the first retention assembly to fold the interior wall of the valve frame onto the delivery catheter, Tensioning the second retention assembly to fold the outer wall of the valve frame onto the inner wall of the valve frame. Folding the outer wall of the valve frame may include tensioning, stretching, or pulling the outer wall of the valve frame distally toward the distal end of the catheter. The method may further include sliding the delivery sheath of the delivery catheter over the collapsed valve.

In another example, a method is provided for performing a mitral valve replacement, comprising positioning a delivery device receiving a folded heart valve assembly in an orthogonally centered position across the native mitral valve, the heart valve assembly being a unibody. comprising a folded stent and attached valve leaflets, retracting the sheath of the delivery device to expose the folded heart valve, expanding the atrial end of the outer wall of the unibody folded stent in the left atrium, Expanding the ventricular end of the outer wall of the body folded stent, expanding the inner wall of the unibody folded stent, and releasing the unibody folded heart valve from the delivery device. The method includes accessing the femoral vein, inserting a transseptal puncture device through the femoral vein into the right atrium, puncturing the intraatrial septum, and inserting a delivery device having a folded heart valve assembly into the left atrium through the femoral vein. Additional steps may be included. In some further examples, expanding the atrial end of the external wall and expanding the ventricular end of the external wall may occur at least partially simultaneously. Dilating the atrial end of the external wall and dilating the internal wall can also occur at least partially simultaneously. The method may also include the step of distending the intraatrial septum. Alternatively, the method further comprises accessing the left thoracic cavity through the chest wall, puncturing cardiac tissue at the apex of the left ventricle, and percutaneously inserting a delivery device having a folded heart valve assembly through the chest wall into the left ventricle. can do. In the latter method, the open end of the unibody folded stent may have a proximal position on the delivery device compared to the transition end of the unibody folded stent which has a distal position on the delivery device. In yet a further embodiment, the method may further include accessing the femoral artery and inserting a delivery device having a folded heart valve assembly through the femoral artery and aortic arch into the left ventricle.

1A and 1B are schematic side and top views of one embodiment of a heart valve stent; Figure 1C is a partial cross-sectional view of the heart valve stent of Figure 1A with part of the external wall omitted; Figure 1D is a schematic cross-sectional view of Figure 1B; Figure 1E is a schematic cross-sectional view of the inner wall of a heart valve stent without the outer wall; Figure 1F is a schematic cross-sectional view of the outer wall of a heart valve stent without the inner wall, and Figure 1F is a schematic cross-sectional view of Figure 1B; Figure 1g is a schematic component drawing of two longitudinal struts from Figure 1a;
2A and 2B schematically illustrate cross-sectional configurations of struts in the outer and inner walls of an exemplary folded stent structure;
3A and 3B schematically show cross-sectional configurations of struts in the outer and inner walls of another exemplary folded stent structure;
4A-4C illustrate various example strut configurations;
Figure 5A is a schematic side view of another embodiment of a heart valve stent with attached leaflets and skirts; Figures 5B and 5C are schematic bottom and top perspective views of the heart valve stent of Figure 5A; Figure 5D is a schematic top perspective view of a variation of the cuff structure of Figure 5C;
Figures 6A-6C are top perspective, top plan, and side views of a skirt structure for use with a heart valve stent; Figure 6D is a cross-sectional view of the skirt structure of Figures 6A-6C;
Figures 7A and 7B are atrium/top and ventricle/bottom views of an implanted heart valve;
8A-8E are schematic cross-sectional illustrations of exemplary deployment procedures for heart valve stents and delivery systems.

Embodiments herein relate to a double-walled, folded stent structure with an inner wall providing a tubular lumen that is attached to a leaflet valve assembly. The interior wall is spaced from a tubular exterior wall configured to seal and/or anchor to the surrounding natural valve anatomy, but is continuous with the interior wall through a transition wall. Transitional walls may result from folding, inversion, or eversion of a single tubular structure into a double-walled unibody tubular stent frame or structure. The stent is configured to be reversibly folded into a reduced diameter or reduced cross-sectional shape for loading onto the catheter and delivery to the target anatomical site, and then re-expand at the implantation site.

In a further embodiment, the folded stent structure may be shaped to have an intermediate region with a reduced cross-sectional size in the outer wall, which may facilitate fixation of the structure over the desired anatomical region. The intermediate region having a reduced diameter or dimension is configured to expand relative to the natural valve leaflet and/or anatomical orifice, while the enlarged diameter or dimension of the end region provides mechanical interference or resistance to displacement. The transition wall of the stent structure may be configured to facilitate fluid entry into the internal lumen through the prosthetic valve leaflets while reducing turbulence and/or hemodynamic forces that may displace or dislodge the valve. For example, the transition wall may be angled or tapered radially inwardly from the outer wall to the inner wall to improve flow compared to a transition wall oriented between the outer and inner walls or perpendicular to the longitudinal axis of the stent structure. Alternatively, the peak force acting on the transition wall can be reduced.

Although some of the exemplary embodiments described herein relate to transcatheter replacement of the mitral valve, the components and structures herein are not limited to any particular valve or delivery method, but include the tricuspid, pulmonary, aortic valve positions, and It may also be amenable to implantation in non-cardiac locations, such as the aorta, venous system, or cerebrospinal fluid system, or in natural or artificial conduits, ducts or shunts. As used herein, spatial reference to the first or upper end of a component may also characterize the anatomical space occupied by the component and/or the relative direction of fluid flow. For example, the first or upper end of the folded stent structure of a prosthetic mitral valve may also be referred to as the atrial end or upstream end of the valve, and the opposite end may be referred to as the ventricular end or downstream end of the valve.

An exemplary embodiment of stent structure 100 is shown in an expanded configuration in FIGS. 1A-1G. The stent structure 100 includes an internal lumen 102 defined by an internal wall 104 . The outer wall 106 is radially spaced from the inner wall 104 through a transition wall 108 and forms an annular cavity 110 . The stent structure 100 has a first closed end 112 located in the transition wall 108, and a second open end 114 of the outer wall 106, wherein the annular cavity 110 is open and accessible. .

The inner lumen 102 includes a first opening 116 surrounded by transition wall 108 and a second opening 118 at the second open end 114 of the stent structure 100. The longitudinal axis 120, 320 of the inner lumen 102 typically coincides with the central axis of the stent structure 100, but in some variations, the inner lumen may be positioned eccentrically relative to the outer wall of the stent structure. . The inner lumen 102 typically includes a circular cross-sectional shape with a generally cylindrical shape between the first opening 116 and the second opening 118, as shown in FIGS. 1A-1D. In other examples, the internal lumen may include a truncated cone, elliptical, or polygonal shape. In some variations, the stent structure can include an internal lumen where the first and second openings can be different in size and/or shape. The length of the inner lumen 102 may range from 10 mm to 50 mm, 15 mm to 40 mm, or 20 mm to 25 mm, and the diameter of the inner lumen along its longitudinal length or maximum cross-sectional dimension may range from 15 mm to 40 mm. mm, 20 mm to 30 mm, or 25 mm to 30 mm. In embodiments where the inner lumen includes a non-cylindrical shape, the difference between the diameter or cross-sectional dimension of the first opening 116 and the second opening 118 is 1 mm to 10 mm, 1 mm to 5 mm, or 1 mm. It may range from mm to 3 mm.

The location of the first and second openings 116, 118 of the inner lumen 102 relative to the overall stent structure 100 may also vary. In some variations, the first opening 116 of the inner lumen 102 may be recessed relative to the first end 112 as shown in FIGS. 1A-1G. In another example, the first opening can be generally flush with the first end transition wall of the stent structure. The position of the first opening 116 is also relative to the longitudinal position of the internal wall 104 or internal connection 122 between the lumen 102 and the transition wall 108, as shown in FIG. 1G. It may be characterized as recessed, coplanar, or protruding relative to the external connection 124 between wall 108 and exterior wall 106. Likewise, the second opening 118 of the inner lumen 102 may also be characterized as being recessed, coplanar, or protruding relative to the longitudinal position of the outer opening 126 of the outer wall 106. For example, in the stent structure 100, the second opening 118 of the inner lumen 102 includes an offset or protruding location relative to the outer opening 126 of the outer wall 106. In some variations, the inner lumen may protrude relative to the second opening in the outer wall, in variants where a smaller or shorter outer wall is desirable to accommodate the smaller size of the native valve anatomy. However, the internal lumen size may remain relatively the same size between different size variants to provide consistent valve geometry and/or hemodynamic properties.

The transition wall 108 of the stent structure 100 has a generally annular and slightly tapered shape surrounding the inner lumen 102 in the expanded configuration, but may have a different shape and/or surface angle in other variations. Referring to Figure 1G, for example, the transition wall 108 in cross-section may comprise a generally linear shape between the inner connection 122 and the outer connection 124, but in other variations it may have a curved shape, e.g. It may have a concave or convex shape. In another variation, the transition wall may have an angle generally perpendicular to the longitudinal axis of the internal lumen. Referring back to FIG. 1G , the transition wall 108 of the stent structure 100 may form an outer acute angle 128 with respect to the longitudinal axis 120 of the inner lumen 102. Angle 128 may range from +45 to +89 degrees, +75 to +89 degrees, or +81 to +85 degrees, with optional variations ranging from ±1 degree, ±2 degrees, ±3 degrees, or ±4 degrees. You can. In other variations, the transition wall angle may range from -45 degrees to +45 degrees, -75 degrees to +75 degrees, or -85 degrees to +85 degrees.

As described above, in some embodiments, the outer wall 106 of the stent structure 100 includes a non-cylindrical shape when in the expanded configuration. The exterior wall 106 may include a first end region 140 that is continuous with a transition wall 108 comprising an exterior convex shape, and a second end region 142 defining an exterior opening 126 . As shown, the internal connection 122 between the upper region of the internal wall 104 and the transition wall 108 has a first or upper internal radius of curvature R 1 along the internal curvature of the bend, and a first or upper internal radius of curvature R ₁ . It may include an internal bend angle (A ₁ ). The bend angle is the angle defined by the arc length of the bend from the center of the radius of curvature between the points at which the bend transitions into a linear segment or a different bend. The external connection 124 between the transition wall 308 and the upper region of the external wall 106 may include a second or upper outer radius of curvature (R ₂ ) and a second or upper outer bend angle (A ₂ ). there is. The middle region of the outer wall 108 includes a third or middle radius of curvature R ₃ and the third or middle bend angle A ₃ , and the lower region of the outer wall 108 includes the fourth or lower radius of curvature. (R ₄ ) and a fourth or lower bend angle (A ₄ ).

As shown in FIG. 1G , the center points of the first and second radii of curvature (R _{1 ,} R ₂ ) may lie within the annular cavity 110 of the stent 100 and the third radius of curvature (R ₃ ) may lie within the annular cavity 110 of the stent 100. It may be outside the outer wall 108 and the fourth radius of curvature R ₄ may be in the ipsilateral annular cavity 110 , the inner lumen 102 or the opposite annular cavity 110b depending on its size.

The radius of curvature and bend angle of the stent structure can be used to define the geometry of the stent in the expanded configuration, but also affects the geometry of the stent in the delivered or collapsed configuration. A region or segment of the stent may be configured to have a smaller radius of curvature and/or a larger bend angle to facilitate folding of the stent in that region or segment when the stent is folded for delivery or a folded configuration. Larger radii of curvature or smaller bend angles may be provided to facilitate straightening of the region or segment for transfer or folded configuration. For example, for stent structure 100, a relatively smaller radius of curvature (R ₁ ) facilitates folding or folding of the stent structure at internal connector 122, while a larger radius of curvature (R ₂ ) Facilitates planarization of the first end region 140 during transfer or loading of the device into the delivery system. Accordingly, in the folded configuration, transition wall 108 is further bent at internal connection 122 and folded around internal wall 104. The outer wall 106 is also folded around the inner wall 104 but not around the transition wall 108. Similarly, the middle region 142 and the second end region 144 of the outer wall 106 may also be provided with larger radii of curvature (R ₃ and R ₄ ), which may be consistent with the concave shape of the middle region 142. and flattening the convex shape of the second end region 144 will also facilitate folding of the outer wall 106. Accordingly, for the stent 100 in the folded configuration, the inner wall 104 will be radially inward relative to the outer wall 106 and the transition wall 108. The outer wall 106 and transition wall 108 will contact the sheath, capsule or outer wall of the delivery system, and the inner wall 104 may contact the inner core or inner catheter wall. In another embodiment, the stent structure has a relatively larger radius of curvature (R ₁ ) and a smaller radius of curvature (R ₂ ) such that, in the folded configuration, the transition wall is folded in a proximal direction relative to the delivery device rather than the interior wall 104 may be provided, where the outer wall 106 is folded relative to both the inner wall 104 and the transition wall 108.

R₃≤R_4, R₁<R₂

R₃

R₄ 또는 R₁<R₂≤R₃≤R₄을 특징으로 할 수 있다.In some variations, the stent geometry may characterize one or more relative properties of the stent in its expanded configuration. For example, stent 100 may have A ₃ >A ₁ and A ₃ >A ₂ and A ₃ >A ₄ and/or R ₁ <R ₂ <R ₃ <R ₄ , R ₁ <R ₂

R ₃ ≤R _4, R ₁ <R ₂

R ₃

It may be characterized by R ₄ or R ₁ <R ₂ ≤R ₃ ≤R ₄ .

Other stent variations include:

1) R ₂ <R ₁ <R ₃ <R ₄ ;

R₃<R₄;2) R ₂ <R ₁

R ₃ <R ₄ ;

R₃

R₄;3) R ₂ <R ₁

R ₃

R ₄ ;

R₂;4) R ₄ >R ₁

R ₂ ;

R₂>R₃;5) R ₄ >R ₁

R ₂ >R ₃ ;

6) A ₂ :A ₁ ratio ranging from 1 to 3, 1.5 to 2.5 or 1.8 to 2.2;

7) A ₃ :A ₄ ratio ranging from 1 to 4, 1.5 to 3.0 or 2.2 to 2.4;

8) A ₂ :A ₄ ratio ranging from 2 to 4, 2.5 to 3.5 or 2.8 to 3.2;

The stent structure of the present disclosure further includes a plurality of integrally formed stent strut segments as shown in FIGS. 1A to 1G. Some struts are integral with longitudinal strut segments 130a, 130b, 130c, or longitudinal struts 130a, 130b, 130c, 132a, 132b, 132c, generally within a radial plane where the longitudinal axis of the stent structure also lies. It may be characterized by lateral strut segments 134a, 134b, 134c formed by, wherein the two longitudinal struts 130, 132 each lie in different adjacent radially oriented planes. 1G , in an embodiment with an even number of equally spaced longitudinal struts, each radial plane 150 is aligned with the longitudinal axis 120 of the stent structure 100 and the stent structure 100. It will include two longitudinal struts 130, 136 located on opposite sides of. The longitudinal and lateral strut segments may also be further grouped into groups of longitudinal strut segments lying in the same radial plane to form longitudinal struts 130 in the interior wall 104 transition wall 108 and/or exterior wall 106. , 132) can form a continuous length.

In some examples, a longitudinal strut comprising a plurality of continuous longitudinal strut segments provided in one wall may terminate or stop at the joint of the next wall, although in some embodiments it may span two or three walls. . In some further embodiments, longitudinal struts may be provided along the entire folded length of the stent structure, between openings of the internal lumen, along the length of the internal wall and through the transition and external walls at the ends of the external wall; , still have each successive strut segment in the same radial plane 150, as shown for longitudinal struts 130, 152 in Figure 1g. This arrangement of multiple continuous longitudinal struts throughout the folded stent structure provides the stent structure with structural integrity that better redistributes the forces acting on the stent structure, with multiple struts welded or attached together, either at the point of manufacture or at the point of use. Less force concentration is found in the stent structure containing components. In another example, a continuous length of longitudinal struts may span all three walls, but the stent may have a different strut configuration, e.g., circumferential struts or tissue, at one or both of the inner and outer ends of the folded stent structure. May include different orientations of anchors.

In the exemplary stent structure 100, the longitudinal strut segments along the internal lumen of the stent structure 100 include a linear configuration, such that the longitudinal strut segments are generally parallel in both the expanded and retracted configurations. Because of this arrangement, the inner lumen 102 does not show any shortening when changing from a collapsed configuration to an expanded configuration. This may reduce or eliminate any axial stretching of the valve structures attached to the internal lumen. This may also allow the internal lumen to be positioned and deployed predictably, reducing the risk of unintentional displacement.

The non-cylindrical configuration of the outer wall 106 may, like the outer wall 106, exhibit some shortening, but the transition from the relatively rectilinear orientation of the contracted configuration to the convex/concave/convex orientation of the expanded configuration, has a shortening effect. or a transition in which the net displacement of an area of the stent structure from the deflated configuration to the deployed configuration may displace the outer wall 106 toward the open end of the stent structure 100 and offset some of the other displacements of the outer wall. This can be controlled or limited by changing the orientation of the wall 108, such that the reduced diameter middle section of the outer wall is generally maintained in a collapsed and expanded configuration. In some variations, the longitudinal movement upon expansion of the stent structure in the reduced diameter middle section of the external wall may be less than 5 mm, 4 mm, 3 mm, 2 mm or 1 mm.

The lateral strut segments may also be characterized by a continuous set of lateral strut segments forming partial or complete circumferential or peripheral struts around the wall of the stent structure. However, lateral strut segments can vary in more than just circumferential orientation. To facilitate expansion and retraction of the entire stent structure, one or more or all of the lateral strut segments may include a pair of inclined legs, each lateral end of each inclined leg having a length of Directional struts are continuous or formed integrally with the segments or struts and each inclined leg is joined together at the center. A bend configuration formed by two angled legs may include a simple bend, but in other examples, each leg may extend centrally to form a hairpin bend region.

The leg angle formed between each leg and the longitudinal strut may vary in different regions of the stent structure and may vary depending on the leg length. 4A, an exemplary configuration of lateral strut segments in the inner wall of the stent structure is shown. Because the amount of radial expansion exhibited by the interior wall compared to the exterior wall is relatively small, the leg lengths of the interior walls in an expanded configuration are typically shorter than the leg lengths found in the exterior walls. Additionally, due to the limited radial expansion, the legs of the internal walls may have a generally linear configuration, since the structural deformation produced at the leg angles is limited. 4B and 4C , in other areas of the stent structure where a greater amount of radial expansion is experienced, such as the outer wall and potentially the transition wall, each leg has a convex curvature along the acute leg angle and a medial It may include a concave curvature along an acute leg angle closer to the bend area.

In some embodiments, the lateral strut segments of the interior wall may include an acute leg angle of 50 degrees, 45 degrees, or less than 40 degrees, or in the range of 30-50 degrees, 35-45 degrees, or 35-40 degrees, and the exterior The acute leg angle of the wall may range from 30-75 degrees, 30-60 degrees, 35-55 degrees, or 40-50 degrees. The longitudinal spacing between longitudinally adjacent lateral strut segments in the inner lumen may be smaller than the longitudinal spacing of the outer wall, for example 2-8 mm, 3-7 mm, 4-6 mm for the inner wall. , 2-6 mm or 3-5 mm, and may be 4-10 mm, 5-10 mm, 6-9 mm. This spacing is also the length of the longitudinal strut segments in the various wall regions.

Referring to Figure 1G, the orientation of the legs and intermediate bends of one or more sets of circumferential strut segments may also be barbed or barbed to bias radially outward relative to adjacent longitudinal struts to resist displacement of the strut structures relative to the native valve tissue. It can provide a force concentration structure. Lateral struts configured with barbs may be positioned anywhere along and/or about the outer wall of the stent structure, but in some variations they may be positioned in the reduced diameter region 142 of the stent structure 100 and the outer opening. It may be located in the outer wall regions 142 and 144 between 126 and oriented toward the reduced diameter region 142. In some further examples, the radially outwardly displaced circumferential struts may be provided with one or more circumferential struts closest to and directed towards the area of the outer wall having the smallest diameter. In a variation of the valve used in mitral valve replacement, barbs may be formed on the strut to engage the subannular tissue on the ventricular side. In some examples, all lateral strut segments of the circumferential struts are radially displaced, while in other examples 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or any of these numbers. Any range between the two may be radially displaced, or all other or all third or fourth lateral strut segments may be radially displaced. The degree of protrusion from the external wall shape defined by the plurality of longitudinal struts may range from 2-10 mm, 2-6 mm or 2-4 mm. In some variations, the barb configuration is a ratio of the radial distance between the barb tip and the longitudinal axis of the stent structure, and the radial distance between the adjacent longitudinal strut or external wall segment (excluding the barb) and the longitudinal axis of the stent structure. It can be characterized as: This ratio may range from 1.1 to 1.5, 1.05 to 1.30, or 1.10 to 1.20.

In some further examples, control holes or attachment structures may be provided on a strut segment or at a connection between two or more strut segments. Control orifices include, but are not limited to, sutures, wires, and hooks that can be released or tensioned to control the expansion, retraction, release, or loading of the stent structure during delivery of the valve prosthesis or loading of the valve prosthesis into a delivery system. It can be used to releasably attach a tensioning member that is not attached to the device. Various embodiments of delivery systems and methods are described in greater detail below. Referring to the example of Figure 1E, control holes are optionally provided at the joints of the ends of each successive longitudinal strut in the outer and inner walls. Additionally, a control hole may optionally be provided in the middle bend of one or both of the two circumferential struts closest to the outer opening 126 of the outer wall 106.

Figure 4A schematically shows an example of a strut configuration 400 that may be provided in an area or wall of a stent structure. Strut configuration 400 includes longitudinal struts 402, 404 and lateral struts 406, 408. Longitudinal strut segments 402a, 404a and lateral strut segments 406, 408 together form a closed perimeter of stent opening or cell 410. Although longitudinal axis 410 and transverse axis 412 are described herein to characterize various geometric configurations of strut configurations, those skilled in the art will understand that other reference points or axes may also be used. Longitudinal axis 410 is parallel to the longitudinal axis of the overall stent structure, while transverse axis 412 is perpendicular to longitudinal axis 412.

In the schematic strut configuration 400 shown in Figure 4A, the longitudinal struts 402, 404 are parallel or non-parallel depending on whether the inner lumen comprises a cylindrical or non-cylindrical shape, for example a frustocone shape. It can be parallel. In variations where the longitudinal struts are non-parallel, the longitudinal struts 402, 404 are angled at about 1 to 5 degrees, 2 to 10 degrees, or 5 to 30 degrees from the longitudinal axis of the stent structure to provide a truncated cone shape. It can have a small radial angle orientation. As shown in Figure 4A, longitudinal and lateral struts 402, 404, 406, 408 may include strut segments 402a, 402b, 404a, 404b, 406a, 406b, 408a, 408b. In some variations, the inner wall 104 of the stent structure 100, the legs 406a, 406b, 408a, 408b of the lateral struts 406, 408, are positioned primarily at the base of the respective lateral struts 406, 408. 406c, 406d, 408c, 408d and bend regions 406e, 408e may include generally linear or rectilinear configurations. In some variants where greater stiffness is desired, the lateral struts may not be substantially uniform along their length. This is achieved by increasing the relative width near the base of the strut and decreasing the relative width in the middle portion of the strut. In this strut configuration 400, the acute angles 414a, 414b, 416a, 416b between the longitudinal struts 402, 404 and legs 406a, 406b, 408a, 408b are 1-45 degrees, 10-40 degrees, or 20 degrees. It can be in the range of -35 degrees. In some variations, the middle region where the leg pairs are integrally formed may include a simple angular or curved configuration, while in other variations the lateral struts have greater curvatures 406f, 408f on the same side as the acute angles. It may include bend regions 406e, 408e with arcuate structures having smaller curvatures 406g, 408g found on the obtuse sides of the directional struts. The bend recess 408h of each bend region 406e, 408e includes a longitudinal length and a lateral width at a smaller curvature 406g, 408g. In some variations, this length and width may be configured to aid force distribution when the stent structure is retracted into a folded or delivery configuration. In some examples, the bend recess has a longitudinal length in the range of 50-500 microns, 50-300 microns, or 50-250 microns and a lateral width in the range of 50-500 microns, 50-350 microns, or 100-300 microns. may include.

In some embodiments, the configuration of the lateral struts with respect to the orientation of the bend region and the relative configuration between the lateral and longitudinal struts may vary. In the example strut configuration 400 of FIG. 4A , both bend regions are oriented toward the transition end or otherwise "directed" toward the upstream end of the valve; however, in other variations, one or more of the bend regions are oriented toward the open end of the valve. or it may be oriented relative to the leg of the lateral strut towards the downstream end.

4B shows another example embodiment of a stent configuration 430 including longitudinal struts 432, 434 and lateral struts 436, 438. Longitudinal strut segments 432a, 434a and lateral strut segments 436, 438 together form a closed perimeter of stent opening or cell 440. Here, the legs 436a, 436b, 438a, 438b of the lateral struts 436, 438 may include a curved or curved configuration in an extended configuration. Legs 436, 438 have a generally convex configuration at bases 436c, 436d, 438c, 438d and a concave configuration at bend regions 436e, 438e. In some variations, the convex/concave configuration may allow for a greater amount of expansion from the transfer configuration to the extended configuration, and/or distribute more stresses and strains along the entire length of the strut leg. The angles 444a, 444b, 446a, 446b between the longitudinal struts 432, 434 and the straight or middle portions of each leg 436i, 436j, 438i, 438j are 25-135 degrees, 45-90 degrees, or 30 degrees. It can be in the range of -60 degrees. The bend region may also include bend recesses 436h, 438h having a longitudinal length and a lateral width that can be configured to adjust the force and force distribution of the stent in the delivered and expanded configurations. One or more bend regions 436e, 438e of each lateral strut 436, 438 may also optionally include control holes 436k, 438k, as described elsewhere herein. In Figure 4B, legs 436a, 436b, 438a, 438b and bend regions 436e, 438e are also oriented in the same direction, but in Figure 4C legs 466a, 466b, 468a, 468b and bend regions 466e , 468e) are oriented in the opposite direction.

The continuous length of each strut segment or longitudinal or lateral strut includes a lateral width or dimension, a radial height or dimension, and a cross-sectional shape. The shape may be generally square, rectangular, trapezoidal or other polygonal shape, circular or oval shape. The lateral width or dimensions of each strut segment can be configured to provide different levels of radial force, with larger widths providing more forces and smaller widths providing less force. In a variant where the stent structure is formed by laser cutting of a tubular base structure, the cross-sectional shape of the strut segments over the elongate length may comprise a segmented annular shape as shown in FIGS. 2A-3B. 2A and 2B, struts 200a and 200b represent struts from the outer and inner walls of the stent structure, respectively. The inner wall strut 200b has an outer convex curvature 202b, i.e. also a greater or longer curvature, furthest from the longitudinal axis of the stent structure, and an inner concave curvature 204b closer to the longitudinal axis of the stent structure. That is, comprising a segmented annular shape with a smaller or shorter curvature, wherein the lateral surfaces 206b, 208b are generally linear in cross-section, but the angular axes 210b, 212b are generally orthogonal to the longitudinal axis of the stent structure. do. Exterior wall struts 200a may initially include the same or similar orientation as interior wall struts 200b, but in embodiments where the exterior wall is formed by everting, exterior wall struts 200a have an everted orientation. whereby the outer curvature 202a about the longitudinal axis of the stent structure is concave and its lesser curvature is also concave, while the inner curvature 204a closer to the longitudinal axis of the stent structure is convex and its greater curvature is concave. The lateral surfaces 206a, 208b have an inclined angular orientation with respect to the longitudinal axis of the stent structure, for example, the angular axes 210a, 210b of the lateral surfaces 206a, 208a are oriented relative to the longitudinal axis of the stent structure. does not intersect with This configuration is also notable in that it is located in different regions of the same longitudinal strut of the unibody folded stent structure formed by eversion. In the expanded state, the corresponding transition wall strut will have a similar configuration to the outer wall strut 200a of the unibody folded stent structure formed by eversion.

Figures 3a and 3b show another example of a folded stent structure with a set of strut configurations of the outer and inner walls resulting from inversion of the laser cut tube to form the inner lumen and wall, rather than the everting configuration shown in Figures 2a and 2b. Another embodiment is shown. 3A and 3B, struts 300a and 300b represent struts from the outer and inner walls of the stent structure, respectively. The outer wall strut 300a has an outer convex curvature 302a, i.e. also a greater or longer curvature, furthest from the longitudinal axis of the stent structure, and an inner concave curvature 304a closer to the longitudinal axis of the stent structure. That is, it includes segmented annular shapes with smaller or shorter curvatures. The lateral surfaces 306a, 308a have angular axes 310a, 312a that are generally linear in cross-section but do not generally slope or intersect the longitudinal axis of the stent structure. The inner wall struts 300b may initially include the same or similar orientation as the outer wall struts 300a, but in embodiments where the inner walls are formed by inversion, the inner wall struts 300b have an inverted orientation. The outer curvature 302b about the longitudinal axis of the stent structure is concave and its smaller curvatures are also concave, while the inner curvature 304b closer to the longitudinal axis of the stent structure is convex and its greater curvatures are also concave. The curvature is concave. The lateral surfaces 306b, 308b have an angular orientation that is neither inclined nor intersecting the longitudinal axis of the stent structure. Like the everted configuration of the folded stent structure, these outer and inner wall configurations are located in different regions of the same longitudinal strut of the unibody folded stent structure formed by inversion. The corresponding transition wall struts in the expanded state will have a similar configuration to the outer wall struts 200a of the unibody folded stent structure formed by inversion. In some variations, the resulting radial forces on the outer wall of the stent structure may cause the everting or inversion process to weaken or adversely affect that portion of the stent structure compared to a portion that does not undergo everting or inversion. It may be larger in the inverted stent structure compared to the stent structure.

The edges of the polygonal shaped struts may be rounded, smooth or sharp. In FIGS. 2A and 2B , corners 214a - 220b include well-defined angled edges, while in FIGS. 3A and 3B corner edges 314a - 320b include rounded corners. Rounded corners and edges may be formed using mechanical polishing, chemical electrolytic polishing, or a multi-step combination thereof, such as mechanical polishing followed by chemical polishing or electrolytic polishing. In some variations, polishing may be performed before any inversion or eversion of the laser cut tube. The dimensions and/or shape of the strut segments or struts may be uniform or may vary along their length. The radial thickness and/or circumferential width of the struts may range from 300-500 microns, 360-460 microns, or 400-500 microns. Strut thickness and/or width may or may not be uniform along the length of the strut segment. As described above, in some instances, a relatively larger width may be provided at the base of the circumferential strut segment and a relatively smaller width may be provided around the intermediate bend area.

The spacing between adjacent longitudinal or circumferential struts may be the same throughout the folded stent structure or may vary along the folded stent structure. For longitudinal struts, the number of struts can vary depending on the desired flexibility or radial expansion force desired for the stent structure or based on the desired strut segment width to achieve the desired radial expansion force or flexibility. In the case of circumferential struts, relatively larger spacings may be provided in areas where greater radial expansion and/or reduced expansion forces are desired, and smaller spacings may be provided in areas where reduced radial expansion and/or greater expansion forces are desired. Spacing may be provided.

The various stent structures described herein may include one or more of the following characteristics.

1) Net longitudinal stent length (i.e., maximum distance spanned by the stent along the longitudinal axis) ranging from 15-60 mm, 20-40 mm, or 25-35 mm;

2) 40-100 mm; 50-90 mm; Folded longitudinal stent length in the range of 60-80 mm (e.g., longitudinal length of continuous longitudinal struts end-to-end when fully unfolded);

3) maximum stent diameter or transverse dimension in the extended configuration ranging from 20-80 mm, 30-60 mm, or 45-55 mm;

4) Maximum external end diameter or transverse dimension in extended configuration ranging from 25-75 mm, 35-65 mm, or 48-58 mm;

5) Maximum transition end diameter or maximum transition end transverse dimension in extended configuration in the range 20-80 mm, 25-55 mm or 40-50 mm, optionally 0-20 mm, 1-15 mm, 2-10 mm, Smaller than the maximum external end or maximum stent diameter or transverse dimension by 2-8 mm or 2-5 mm;

6) internal lumen length ranging from 10-50 mm, 15-40 mm, or 20-26 mm;

7) Internal lumen diameter or maximum cross-sectional dimension in the range of 10-40 mm, 15-35 mm or 26-31 mm;

8) inner upper radius of curvature (R ₁ ) in the range of 1-10 mm, 2-8 mm or 3-5 mm;

9) inner upper bend angle ranging from 0-180 degrees, 60-135 degrees, or 75-90 degrees, or 83 degrees;

10) transition wall external angle relative to the longitudinal axis of the stent structure ranging from 0-180 degrees, 45-100 degrees, 75-90 degrees, or 90 degrees;

11) Transition wall radial width ranging from 5-30 mm, 5-20 mm, or 5-10 mm;

12) External upper radius of curvature (R ₂ ) ranging from 0.5-6 mm, 1.5-5 mm, or 2.5-4 mm;

13) External upper bend angle (A ₂ ) ranging from 45-270 degrees, 90-235 degrees, 135-200 degrees, or 160-200 degrees;

14) External wall longitudinal length in the range of 10-40 mm, 20-35 mm or 25-30 mm;

15) External wall curve length in the range of 10-50 mm, 20-50 mm or 30-40 mm;

16) External wall longitudinal strut length from the external end to the transition wall ranging from 12-50 mm, 20-40 mm, or 25-35 mm;

17) Radius of curvature of the outer wall mid-zone in the range of 1-15 mm, 3-12 mm, 4-8 mm or 3-6 mm;

18) Exterior wall mid-zone bend angle ranging from 10-180 degrees, 30-160 degrees, 60-160 degrees, or 80-140 degrees;

19) External wall open end area or sub-area radius of curvature (R ₄ ) in the range 5-100 mm, 5-40 mm, mm or 10-20 mm;

20) exterior wall open end zone or lower zone bend angle (A ₄ ) ranging from 1-90 degrees, 10-90 degrees, 20-80 degrees, or 30-70 degrees;

21) the maximum radial difference between the smallest and largest radii in the same radial plane of the outer wall of the stent structure is in the range of about 6-15 mm, 8-12 mm, 9-11 mm, or about 10 mm;

22) the maximum radius of the first end/atrial/upper region of the external wall ranging from 20-30 mm, 22-28 mm, or 24-27 mm;

23) Minimum radius of the middle area of the exterior wall in the range of 10-30 mm, 12-25 mm, or 15-20 mm;

24) the maximum radius of the second end/ventricular/lower region of the external wall ranging from 20-35 mm, 25-30 mm, or 26-29 mm;

25) a longitudinal length to diameter ratio ranging from 0.40 or 1.0, 0.45 to 0.80, or 0.50 to 0.60;

26) a plurality of longitudinal struts, divisible by a number selected from the group consisting of one or more of three, for example 3, 6, 9, 12, 15 longitudinal struts;

27) a radial distance between the barb tip and the longitudinal axis of the stent structure, and adjacent longitudinal struts or external wall segments (excluding barbs) ranging from 1.1 to 1.5, 1.05 to 1.30, 1.05 to 1.20, or 1.05 to 1.15; The ratio between the radial distances between the longitudinal axes of the stent structure; and/or

28) positive (i.e. protruding from the external opening), neutral (i.e. flush with the external opening), negative (i.e. recessed from the external opening), and/or -4 to -12 mm, -5 to -10 mm, -6 to -9 mm, +1 to +8 mm, +2 to +6 mm, +3 to +5 mm, -3 to +3 mm; The inner opening position relative to the outer opening position along the longitudinal axis ranging from +0 to +3 mm, -12 to +5 mm, -6 to +6 mm, or -7 mm to +4 mm.

The scope of stent structures described herein need not be limited to require selection of each of the properties mentioned above, and single properties or subsets of properties are also contemplated. For example, in some variations, the stent structure, which may or may not be provided with valve and/or skirt material, may be as follows:

1) Folded unibody stent structures with an everted outer wall strut configuration or an inverted inner wall strut configuration;

2) the number of longitudinal struts can be divided by 3; A folded unibody stent structure having a non-shortened inner lumen and optionally a shortened outer wall, with a radial strut thickness in the range of 400-450 microns and a longitudinal length to diameter ratio in the range of 0.50 to 0.60;

3) A folded unibody stent structure comprising an upper inner radius of curvature that is smaller than the upper outer radius of curvature, an inner lumen extending from 0 to 3 mm from the outer opening of the outer wall, and a barb to outer wall radius ratio ranging from 1.1 to 1.2. ; or

4) A folded double-wall unibody stent structure with 12 longitudinal struts and 3-5 circumferential struts in the inner lumen, 1-2 circumferential struts in the transitional wall, and 3-5 circumferential struts in the outer wall.

1A-1G, the stent structure 100 includes a plurality of end-to-end longitudinal struts and a plurality of circumferential lateral struts, each in turn a continuous longitudinal or lateral strut segment. Each contains a consecutive set of . In the specific example of the stent structure 100, twelve equally spaced end-to-end longitudinal struts are provided, and along the folded stent structure 100 nine sets of complete circumferential struts are provided. Four sets of closely spaced circumferential struts are provided along the inner wall, with legs that are either relatively straight or minimally curved and whose intermediate bends are oriented to point towards the upper or closed end of the stent structure. The transition wall 108 is a set of circumferential struts with a relatively increased base curvature at each leg and a relatively reduced curvature around the intermediate bend oriented to point radially outward toward the outer wall 106. Includes. The outer wall 106 includes four sets of circumferential struts, the middle bend of which is the set of circumferential struts closest to the opening of the outer wall 106 that can be oriented toward the open end of the stent structure 100. Except, it is oriented toward the closed end of the stent structure 100. The orientation of the legs and intermediate bends in the third set of circumferential struts may also be biased radially outward relative to the adjacent longitudinal struts to provide barbed or force-concentrating structures to resist displacement of the strut structures relative to the native valve tissue. there is. Typically, these radially outwardly displaced circumferential struts are closest to the outer wall portion between the narrowest diameter of the stent structure and the downstream or open end, as shown in Figures 1A and 1C. It may be provided on one or more circumferential struts oriented diametrically or towards the inlet/upstream end.

As described above, control holes are also provided at the outer end or connection of the longitudinal struts and circumferential struts at the outer end of the stent structure 100 and, in the inner lumen, at the longitudinal struts and the circumferential struts at the inner end of the stent structure. Provided at the inner end or joint of the strut. Control holes are also provided in the middle bends of the two circumferential struts closest to the outer ends of the stent structure 100.

For the stent structure 100, the net longitudinal stent length can be 25 to 35 mm, the folded longitudinal stent length can be 60 to 90 mm, and the maximum stent diameter or transverse dimension in the expanded configuration is 45 mm. to 55 mm, and in the expanded configuration the maximum external end diameter or transverse dimension may be 45 to 55 mm, and in the expanded configuration the maximum transition end diameter or transverse dimension may be 40 to 50 mm, and the maximum The outer end or maximum stent diameter or transverse dimension may be 1 to 5 mm smaller, the inner lumen length may be 20 to 25 mm, the inner lumen diameter or maximum cross-sectional dimension may be 20 to 30 mm, and the inner upper curvature The radius may be 3 to 5 mm, the inner upper bend angle may be 90 to 105 degrees, the transition wall outer angle with respect to the longitudinal axis of the stent structure may be 75 to 90 degrees, and the transition wall radial width may be 15 degrees. to 20 mm, the external upper radius of curvature may range from 1 to 4 mm, the external upper bend angle may range from 160 to 200 degrees, the external wall longitudinal length may range from 20 to 25 mm, and the external wall The curve length may be 25 to 40 mm, the external wall longitudinal strut length from the external end to the transition wall may be 25 to 35 mm, and the external wall mid-region radius of curvature may be 3 to 6 mm, and the external wall mid-region radius of curvature may be 3 to 6 mm. The zone bend angle can be from 60 to 120 degrees, and the outer wall open end zone or lower zone radius of curvature can be 10 to 50 mm, 10 to 30 mm, or 10 to 20 mm, and the outer wall open end zone or lower zone radius of curvature can be from 10 to 50 mm, 10 to 30 mm, or 10 to 20 mm. The bend angle may be 20 to 135 degrees, 30 to 90 degrees, or 50 to 70 mm, and the maximum radial difference between the smallest and largest radii in the same radial plane of the stent structure will be 9 to 11 mm. The inner opening position relative to the outer opening position along the longitudinal axis can be -6 to -9 mm, and/or can be negative.

1A-1F , stent structure 100 also includes 12 continuous longitudinal struts and 9 circumferential struts as in stent structure 100. The stent structure 100 includes four circumferential struts along the inner lumen 102, although other variations could have two, three, five or six circumferential struts in the inner lumen. The orientation of the circumferential struts of the inner wall 104 is also directed toward the closed end of the stent structure 100 and the circumferential struts of the transition wall 108 are oriented radially outwardly, but in some variations, one or more circumferential struts are oriented radially outwardly. The directional struts are oriented radially inward and/or towards the open end of the stent structure, for example the circumferential strut closest to the open end of the external wall. Other optional variations may include the transition wall having an orthogonal orientation with respect to the longitudinal axis, while the transition wall 108 of the stent structure 100 is slightly or substantially angled. It is hypothesized that an inward angled transition wall may reduce turbulent or non-laminar flow into the opening of the internal lumen, or peak axial forces that could dislodge the stent structure from its target position during atrial contraction.

In various embodiments described herein, the upper end or transition end of the stent structure is configured to be used as an upstream end of a prosthetic valve, and blood flow passes through the valve structure received at the transition end of the internal lumen and attached to the internal lumen. do. The valve structure may be any of a variety of valve structures, including flap valves, ball-in-cage valves, or leaflet valves. Leaflet valve materials may include autologous, allogeneic or xenogeneic or artificial materials, such as natural materials or anatomical structures such as porcine, bovine or equine pericardial tissue or valves, or biomaterials derived from the patient's own cells; The valve may be immobilized with any of a variety of chemicals, such as glutaraldehyde, to reduce its antigenicity and/or alter the physiological and/or mechanical properties of the valve material. If a leaflet valve is provided, the leaflet valve may be of bi- or tri-lobed leaflet structure. The connection portions of the valves may be attached or sutured to longitudinal and/or circumferential struts of the internal lumen, for example, every fourth longitudinal strut of the stent structure 100 provided with a three-leaflet valve.

The prosthetic valve may further include one or more skirt materials for one or more regions of the stent structure. The skirt material may comprise a solid, tight weave, or loosely braided sheet of autologous, homogeneous or xenogeneic or artificial material that may be the same or different from the leaflet material of the valve. The skirt material may include polytetrafluoroethylene (PTFE), polyester, or polyethylene terephthalate (PET) material. In variations involving open pore materials, the average pore size may range in size from about 0.035 mm to 0.16 mm, or 0.05 mm to 0.10 mm, or 0.07 mm to 0.09 mm. Open pore materials can provide greater elasticity or flexibility in areas of the stent structure that have experienced greater compositional changes. Other areas of the stent may be provided with a void-free, solid sheet material that does not require elasticity or flexibility. The skirt material may include a single layer or a multilayer structure and may include one or more coatings to modulate thrombus formation, tissue ingrowth, and/or lubricity.

5A-5C show an example of a prosthetic valve 500 with a skirt 502 comprising two different materials attached to a stent structure 504. In this particular embodiment, a solid or tight woven material is provided as a cuff structure 506 around the outer and inner surfaces of the downstream or lower region 508 of the outer wall 510. The outer surface of the inner wall 512 is provided with identical or different cuff structures of solid or tight woven material. Figure 5C shows a variant with a separate material for the inner wall 512, and Figure 5D shows another variant with the same cuff structure spanning the annular cavity 522 and covering the outer surface of the inner wall 512. An example is shown. The porous braided material is positioned against the upper region 516 of the outer wall 510, another cuff structure 514 around the transition wall 518 and the upstream opening 520 of the inner wall 512 of the stent structure 504. It is used in Artificial or animal derived materials may be used to form the valve pocket and valve leaflets 516a-c located in the internal lumen 512. In addition to providing elasticity to expand with expansion of the stent structure, porous braided materials can also provide cell migration and tissue ingrowth into the prosthetic valve. This dual-material skirt 502 allows blood to flow into the annular cavity 522 to pass through the porous material of the cuff structure 514, but the porous material has porosity small enough to resist passage of blood clots that may form. This can be provided.

In another variation shown in Figures 6A-6D, the skirt 600 includes a tubular material. The shaped skirt 600 may provide a more consistent attachment of the skirt 600 to the stent structure with less potential problems due to excess sheet material in narrower stent areas. In this particular variant, the skirt 600 includes an interior central cavity 602 defined by the interior wall 604, and an interior annular cavity 606 between the interior wall 604 and the shaped exterior wall 608. do. The outer wall 606 is shaped in a configuration complementary to the outer wall of the stent structure, for example, an enlarged upstream region 610, a reduced diameter intermediate region 612, and an enlarged diameter downstream region 614. It can be. The skirt 600 is positioned over the closed end of the stent structure such that the stent structure is positioned in the annular cavity 606, and the inner wall 604 of the skirt 600 is positioned within the inner lumen of the stent structure. In some variations, the inner wall 604 can be inverted into the inner lumen of the stent structure. A tapered annular skirt 616 may be provided to span the annular cavity 606 between the inner wall 604 and the shaped outer wall 608. The exterior wall 608 of the skirt 602 can be heat set in an expanded configuration and spans the entire exterior wall 606, the transition wall 618 of the skirt 602, and optionally a portion of the interior wall 606. A porous or knitted material that is sewn, glued, and/or welded to a tubular, tight woven material configured to line the inner lumen of the stent structure. The tapered annular skirt 616 may also be sewn and glued to the inner surface of the outer wall 606 and the outer surface of the inner wall 604 after the outer wall 606 and inner wall 604 are initially assembled with the stent structure. , welded, or otherwise attached. Similarly, the valve leaflet structure may be sewn, glued, welded, or otherwise attached to the inner wall 604 of the skirt 600 after the inner wall 604 is inserted into the inner lumen of the stent structure.

The skirt material may be sutured to the outer and/or inner surfaces of the inner wall, transition wall, and/or outer wall of the stent, and in some variations, may span over the inner and outer surfaces of the stent wall, or may span the inner or outer surfaces of one wall. Provided as a cuff or folded structure over the outer end, inner end or transition wall of the stent structure to transition from the outer surface to another wall, for example to line the annular cavity of a prosthetic valve, for example the inner surface of the outer wall. , can cover the inner surface of the transition wall and the outer surface of the inner wall.

7A and 7B are photographs of an exemplary prosthetic valve 700 with a dual material skirt as described for FIGS. 5A and 5B above used in a mitral valve animal study and explanted 30 days later. On the atrial side of the valve 700 shown in FIG. 7A , good ingrowth was found at the border or connection between the large void knit fabric 702 and the tight woven fabric as well as tissue or cell ingrowth into the large void knit fabric 702. , Good tissue ingrowth is noted on the ventricular side of the valve 700, which is primarily covered by a tight woven fabric 704 with small voids around the outer and inner openings 706, 708.

manufacturing

In some variations, the stent structure can be fabricated using superelastic Nitinol tubing that is laser cut into various slits and slots to achieve the initial tubular stent shape. Next, in a series of cyclical deformation, heating, and cooling steps, the tubular stent is expanded step by step to at least the initial size of the internal lumen of the stent structure. Thereafter, the portions of the stent structure corresponding to the transition wall and the external wall are further expanded stepwise to the desired diameter, followed by stepwise eversion to form the external wall using a mandrel, stepwise reduction of the middle region of the external wall, or external Further expansion of the upstream and downstream end regions of the wall is performed to achieve a reduced diameter shape of the outer wall. In another step, one or more bend regions in the lateral struts around the intermediate region are displaced radially outward to form retaining barbs or structures.

In an alternative embodiment, after the initial cut of the tube, the tube may be subjected to a series of cyclic deformation, heating, and cooling steps to expand the tube in a stepwise manner to at least the initial size of the outer lumen of the stent structure, and thereafter to the transition wall. and the portion of the stent structure corresponding to the inner wall is inverted to the outer wall to form a closed end and inner wall. The outer wall can be further expanded or adjusted to the desired shape step by step, for example by further expanding the open and closed end regions of the outer wall or reducing the cross-sectional size or diameter of the intermediate region. One or more bend regions in the lateral struts around the intermediate region may also be displaced radially outward to form retaining barbs or structures.

Valve loading and delivery

As mentioned above, a plurality of control holes may be provided on the stent structure, which may be provided with one or more sutures to control the expansion and contraction of different regions on the stent structure, and/or to control the stent structure until final deployment at the treatment site. It may be used to attach one or more hooks for releasable retention. In another example, instead of using control holes, sutures or wraps may be provided over the exterior of one or more areas of the stent structure.

In some examples, the sutures may be tensioned or secured to fold the outer and inner walls of the stent structure for loading the delivery catheter. The suture can be manipulated to fold the inner wall first before the outer wall, or it can be manipulated to fold both simultaneously. Similarly, one end of the interior or exterior wall may be folded first, and both ends of the interior or exterior wall may be folded simultaneously. This can be done at room temperature or in a sterile cold water or ice water bath at the point of use or manufacture. After folding, the sheath can be extended distally over the portion of the distal catheter containing the prosthetic valve. Additionally, the valve may be rinsed with sterile saline prior to loading to remove any preservative remaining on the valve.

In some variations, the transition wall of the stent structure is folded down at the internal connection, such that in the folded configuration the transition wall is positioned directly over the delivery catheter or device like the interior wall, but in other examples, the exterior wall is folded and It is pulled distally during loading and unfolds the transition wall at the outer connection such that when retracted into the folded configuration the transition wall is positioned radially outward from the inner wall.

The retention suture of the delivery system may be further configured to lock in place except during movement via a bias spring or mechanical interfitting locking arrangement, as known in the art, a pulling ring, a sliding lever, and/or It can be controlled in the proximal direction by the user using a rotary knob. The proximal end of the delivery system can also be robotically controlled using any of a variety of robotic catheter guidance systems known in the art. The suture may be slid along one or more internal lumens of the delivery catheter in addition to any flush lumen, guidewire lumen, or steer wire lumen(s) provided, including quick exchange guidewire configurations. The sutures may exit at different locations around the distal area of the delivery catheter and may exit around the distal area of the catheter through multiple openings. The multiple openings may be spaced around the circumference of the catheter body and/or longitudinally, depending on the area of the stent structure controlled by the sutures.

In one exemplary method of delivering a prosthetic valve, the patient is positioned on an operating table and draped and sterilized in the usual manner. Anesthesia or sedation is achieved. Percutaneous or angiotomy access is made to the femoral vein, and an introducer guidewire is inserted. The guidewire is manipulated to reach the right atrium, then a Brockenbrough needle is positioned and used to puncture the atrial septum to achieve access to the left atrium. Alternatively, image guidance can be used to detect patent septum ovale or whether a remnant approach is valid, and the guidewire can be passed through an existing anatomical opening. Balloon catheters may also be used as needed to enlarge the opening across the atrial septum. Electrocautery catheters can also be used to create an opening in the atrial septum. Upon entering the left atrium, the guidewire advances through the mitral valve into the left ventricle. Preformed guide catheters or balloon catheters can be used to facilitate crossing the mitral valve. Once in the left ventricle, a delivery catheter with an artificial valve is inserted over a guidewire.

Referring to FIG. 8A , delivery system 800 having delivery catheter 802 and valve 804 is positioned over mitral valve opening 806. Delivery system 800 may also be further manipulated to adjust the angle of entry through mitral valve opening 806 to be approximately perpendicular to the natural valve opening and/or centered with mitral valve opening 806. Once the desired catheter position is achieved, the delivery sheath 808 is withdrawn proximally to expose the folded valve 804.

8B, the set of sutures controlling the release of the ventricular end 810 or downstream of the outer wall 812 of the valve 804 is partially released, while the tension member controlling the inner wall 816 is tensioned. maintain the status quo Next, in FIG. 8C , the ventricular end 810 of the outer wall 812 of the valve 804 is further released to add the ventricular end, middle region, and more atrial end 814 of the outer wall 812. causing the transition wall 816 of the valve 802 to expand at least partially outward. Partial expansion of the atrial end 814 and ventricular end 810 of the valve 802 helps further center and orient the middle region 822 of the valve 802 orthogonally prior to complete release. In this embodiment the initial expansion of the atrial end 814 of the external wall 812 is a secondary effect from the partial release of the ventricular end 810 of the valve 802 as the longitudinal tension is released, whereas in other examples Independent tensioning member control of the atrial end 814 may be provided.

In FIG. 8D , the tension members of the ventricular end 810 and the atrial end 814 are further released, either simultaneously or separately, in a stepwise manner, further releasing the intermediate region 820 of the outer wall 812 relative to the valve opening 806. It meshes with. This further expansion of the outer wall 812 also exposes the retaining barbs or protrusions 822 on the outer wall 812. Recheck proper centering and orientation of the valve to ensure that the valve has not developed into an inclined or partially disengaged position with respect to the mitral annulus. In some variations, the tension member may be re-tensioned to refold the valve 804, which may be performed to facilitate repositioning and/or reorientation of the valve 804. Once confirmed, the tension members of the inner wall 818 can be released as shown in Figure 8E, which also allows the outer wall 812 to achieve unrestrained expansion relative to the mitral valve opening 806. The tension member can then be cut or otherwise released or separated from the valve and the tension member can be drawn into the catheter and optionally out of the proximal end of the catheter. The delivery catheter and guidewire can then be withdrawn from the patient and hemostasis is achieved at the femoral vein site.

In one exemplary method of delivering a prosthetic valve, the patient is positioned on an operating table and draped and sterilized in the usual manner. Anesthesia or sedation is achieved. Percutaneous or angiotomy access is made to the vessel or entry site, for example in the femoral vein, femoral artery, radial artery, or subclavian artery, and an introducer guidewire is inserted. Manipulate the guide wire to reach the desired valve implantation site. Preformed guide catheters or balloon catheters can be used to facilitate crossing the valve implantation site.

Referring to FIG. 8A , delivery system 800 having delivery catheter 802 and valve 804 is positioned over valve opening 806. Delivery system 800 may also be further manipulated to adjust the angle of entry through valve opening 806 to be approximately perpendicular to and/or centered with valve opening 806. Once the desired catheter position is achieved, the delivery sheath 808 is withdrawn proximally to expose the folded valve 804.

8B, the set of tension members controlling the release of the downstream end 810 of the outer wall 812 of the valve 804 is partially released, while the tension members controlling the inner wall 816 are tensioned. maintain. Next, in FIG. 8C , the downstream end 810 of the outer wall 812 of the valve 804 is further released, adding a downstream end, middle region, and more upstream end 814 of the outer wall 812. causing the transition wall 816 of the valve 802 to expand at least partially outward. Partial expansion of the atrial end 814 and ventricular end 810 of the valve 802 helps further center and orient the middle region 822 of the valve 802 orthogonally prior to complete release. In this embodiment the initial expansion of the atrial end 814 of the external wall 812 is a secondary effect from the partial release of the ventricular end 810 of the valve 802 as the longitudinal tension is released, whereas in other examples Independent tension member control of the upstream end 814 may be provided.

In FIG. 8D , the tension members of the downstream end 810 and the upstream end 814 are further released, either simultaneously or separately, in a stepwise manner, further releasing the intermediate region 820 of the outer wall 812 relative to the valve opening 806. It meshes with. This further expansion of the outer wall 812 also exposes the retaining barbs or protrusions 822 on the outer wall 812. Recheck proper centering and orientation of the valve to ensure that the valve has not been deployed in an inclined or partially disengaged position relative to the valve annulus. The tension member may optionally be re-tensioned to refold the valve 804, which may be performed to facilitate repositioning and/or reorientation of the valve 804. Once confirmed, the tension members of the inner wall 818 are released as shown in Figure 8E, which also allows the outer wall 812 to achieve unrestrained expansion relative to the mitral valve opening 806. The tension member can then be separated from the valve 804 and drawn into the catheter and optionally out of the proximal end of the catheter 802.

In another exemplary method of delivering a prosthetic valve, the patient is positioned on a surgical table and draped and sterilized in the usual manner. Anesthesia or sedation is achieved with selective ventilation of the right lung and optionally the left upper lobe of the lung to allow controlled folding of the left lower lobe of the lung. The encapsulated suture is placed transepically or at another cardiac inlet site. The trocar is inserted through a cannula or introducer with a proximal hemostatic valve, and the trocar assembly is inserted through a scapular suture to access the ventricle and target valve.

Referring to FIG. 8A , delivery system 800 with delivery rigid tool 802 and valve 804 is positioned over valve opening 806. Delivery system 800 may also be further manipulated to adjust the angle of entry through valve opening 806 to be approximately perpendicular to the natural valve opening and/or centered with the valve opening 806. Once the desired instrument posture is achieved, the delivery sheath 808 (if present) is withdrawn proximally to expose the folded valve 804.

8B, the tension member controlling the release of the downstream end 810 of the outer wall 812 of the valve 804 is partially released, while the suture controlling the inner wall 816 remains tensioned. do. Next, in FIG. 8C , the downstream end 810 of the outer wall 812 of the valve 804 is further released, adding a downstream end, middle region, and more upstream end 814 of the outer wall 812. causing the transition wall 816 of the valve 802 to expand at least partially outward. Partial expansion of the atrial end 814 and ventricular end 810 of the valve 802 helps further center and orient the middle region 822 of the valve 802 orthogonally prior to complete release. In this embodiment the initial expansion of the atrial end 814 of the external wall 812 is a secondary effect from the partial release of the ventricular end 810 of the valve 802 as the longitudinal tension is released, whereas in other examples Independent suture control may be provided.

In FIG. 8D , the tension members of the downstream end 810 and the upstream end 814 are further released, either simultaneously or separately, in a stepwise manner, further releasing the intermediate region 820 of the outer wall 812 relative to the valve opening 806. It meshes with. This further expansion of the outer wall 812 also exposes the retaining barbs or protrusions 822 on the outer wall 812. The tension member may optionally be re-tensioned to refold the valve 804, which may be performed to facilitate repositioning and/or reorientation of the valve 804. Recheck proper centering and orientation of the valve to ensure that the valve has not been deployed in an inclined or partially disengaged position relative to the valve annulus. Once confirmed, the tension members of the inner wall 818 are released as shown in Figure 8E, which also allows the outer wall 812 to achieve unrestrained expansion relative to the mitral valve opening 806. The suture may then be cut and the cut end may be drawn into the catheter and optionally out of the proximal end of the delivery tool 802.

Although the embodiments herein have been specifically shown and described with reference to the embodiments, those skilled in the art will understand that various changes in form and details may be made therein without departing from the scope of the embodiments. For all of the above-described embodiments, the method steps do not need to be performed sequentially.

Claims (18)

It is an artificial heart valve,
A unibody stent frame with folded double walls, the stent frame comprising:
Collapsed and expanded configurations;
An outer wall containing an open enlarged diameter region, an intermediate reduced diameter region, and a closed enlarged diameter region:
a tubular inner wall with a central lumen; and
A unibody stent frame comprising a transition wall between an external wall and an internal wall; and
A valve comprising a prosthetic leaflet valve located in the central lumen of the internal wall. The valve of claim 1 , wherein the unibody stent frame further comprises a first fold between the closed enlarged diameter region and the tubular interior wall. The valve of claim 2 , wherein the unibody stent frame comprises a second fold between the closed and open expansion regions. The valve of claim 1 , wherein the outer wall surrounds at least 70% of the inner wall in the expanded configuration. The valve of claim 4, wherein the outer wall and transition wall completely surround the inner wall in the folded configuration. The valve of claim 1 , wherein the tubular interior wall comprises a non-shortened region surrounding the prosthetic valve when transitioning from a folded configuration to an expanded configuration. The valve of claim 1 , wherein the inner wall is a non-shortened inner wall and the outer wall is a shortened outer wall. 4. The valve of claim 3, wherein the radius of curvature at the first fold is smaller than the radius of curvature at the second fold. The valve of claim 1 , wherein the unibody stent frame further comprises a plurality of longitudinal struts, each longitudinal strut being positioned sequentially along the inner wall, transition wall and outer wall. The valve of claim 9, wherein, for at least one of the plurality of longitudinal struts, successive segments of the longitudinal struts located on the inner wall, transition wall and outer wall are coplanar. The valve of claim 9 , wherein the continuous segments of the longitudinal struts are also coplanar with the central longitudinal axis of the unibody stent frame. The valve of claim 9, wherein the plurality of longitudinal struts are formed integrally with the plurality of circumferential struts. 13. The valve of claim 12, wherein at least three circumferential struts are located on the outer wall. The method of claim 1 further comprising a stent covering, the stent covering comprising:
a first region on the exterior surface of the exterior wall;
a second region on the open end of the exterior wall;
a third region on the outer surface of the transition wall;
a fourth region on the inner surface of the inner wall;
a fifth region on the open end of the interior wall;
a sixth region on the outer surface of the inner wall;
a seventh region on the interior surface of the exterior wall; and
A valve comprising an eighth zone portion between the inner surface of the outer wall and the outer surface of the inner wall. According to clause 14,
Portions of the first, second, third and fourth regions comprise a first fabric structure;
Portions of the fourth and fifth regions include a second fabric structure;
The valve wherein the sixth, seventh and eighth regions comprise a third textile structure. The valve of claim 15 , wherein the first fabric structure and the third fabric structure comprise a first fabric material, and the second fabric structure comprises a second fabric material different from the first fabric material. 17. The valve of claim 16, wherein the first fabric material is less permeable and thinner than the second fabric material. 13. The method of claim 12, wherein the plurality of longitudinal struts and the plurality of circumferential struts comprise a segmented annular cross-sectional shape, and wherein the orientation of the segmented annular cross-sectional shape at the inner wall is such that the plurality of longitudinal struts and the plurality of circumferential struts comprise a segmented annular cross-sectional shape at the inner wall. Valves, opposite in orientation.

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