Patent Description:
Cardiac valves exhibit two types of pathologies: regurgitation and stenosis. Regurgitation is the more common of the two defects. Either defect can be treated by a surgical repair. Under certain conditions, however, the cardiac valve must be replaced. Standard approaches to valve replacement require cutting open the patient's chest and heart to access the native valve. Such procedures are traumatic to the patient, require a long recovery time, and can result in life threatening complications. Therefore, many patients requiring cardiac valve replacement are deemed to pose too high a risk for open heart surgery due to age, health, or a variety of other factors. These patient risks associated with heart valve replacement are lessened by the emerging techniques for minimally invasive valve repair, but still many of those techniques require arresting the heart and passing the blood through a heart-lung machine.

Efforts have been focused on percutaneous transluminal delivery of replacement cardiac valves to solve the problems presented by traditional open heart surgery and minimally-invasive surgical methods. In such methods, a valve prosthesis is compacted for delivery in a catheter and then advanced, for example, through an opening in the femoral artery and through the descending aorta to the heart, where the prosthesis is then deployed in the aortic valve annulus.

In view of the foregoing, it would be desirable to provide a valve prosthesis that is capable of conforming to a patient's anatomy while providing a uniform degree of rigidity and protection for critical valve components. Protection for critical valve components is essential to maintain reliability for the valve prosthesis.

Document <CIT> relates to a prosthetic valve having a tapered tip when compressed for delivery.

Provided herein are valve prostheses that generally include a self-expanding frame, where the valve prosthesis is sutured to the self-expanding frame. Such configurations achieve numerous goals. For example, such configurations can: prevent the native leaflets from obstructing flow through the left ventricular outflow tract (LVOT); prevent the native leaflets from interacting with the prosthetic leaflets; recruit the native leaflets in minimizing perivalvular leaks; maintain proper alignment of the valve prosthesis; avoid systolic anterior mobility; and maintain valve stability by preventing migration of the valve into the atrium or ventricle. The design of the prosthesis also mimics the native valve and supports a non-round in vivo configuration, which better reproduces native valve function.

The invention is therefore directed to a valve prosthesis as defined in claim <NUM>. Particular embodiments are defined in dependent claims <NUM> - <NUM>. Further disclosed herein are aspects of a valve prosthesis which is generally designed to include a valve body including a plurality of valve leaflets affixed to the skirt and a frame including a distal inflow section, a proximal outflow section, and a valve section between the inflow section and the outflow section. The valve body is attached to the frame in the valve section at a plurality of commissure points. The frame includes a radially repeating cell pattern in the inflow section and the valve section. The outflow section includes a plurality of loops, the loops being attached to the valve section at a plurality of junctions. A plurality of valve section cells are positioned between each junction in a radial direction.

disclosed herein are aspects of a valve prosthesis which is generally designed to includes a valve body including a plurality of leaflets affixed to a skirt and a frame including a first tubular structure, a second tubular structure, and a plurality of junctures attaching the first tubular structure to the second tubular structure. The valve body is attached to the frame in the first tubular structure and after implantation of the valve prosthesis in a patient, the first tubular structure is aligned on a first axis and the second tubular structure is aligned on a second axis.

Further disclosed but not claimed is a method of treating a valve disorder in a patient's heart which generally includes collapsing a valve prosthesis to form attachments at a proximal end of the valve prosthesis engaging attachment tabs connected to a delivery system; delivering the delivery system and valve prosthesis to a heart; expanding the valve prosthesis in the heart such that attachments are not formed; and withdrawing the delivery system from the heart. In the expanded configuration, the valve prosthesis is not engaged with the attachment tabs.

The accompanying figures, which are incorporated herein, form part of the specification and illustrate embodiments of a valve prosthesis. Together with the description, the figures further serve to explain the principles of and to enable a person skilled in the relevant art(s) to make, use, and implant the valve prosthesis described herein. In the drawings, like reference numbers indicate identical or functionally similar elements.

The following detailed description of a valve prosthesis refers to the accompanying figures that illustrate exemplary embodiments. Other embodiments are possible. Modifications can be made to the embodiments described herein without departing from the scope of the present invention. Therefore, the following detailed description is not meant to be limiting.

The present invention is directed to a heart valve prosthesis having a self-expanding frame that supports a valve body. The valve prosthesis can be delivered percutaneously to the heart to replace the function of a native valve. For example, the valve prosthesis can replace a bicuspid or a tricuspid valve such as the aortic, mitral, pulmonary, or tricuspid heart valve.

In one aspect of the invention, the valve body comprises three leaflets that are fastened together at enlarged lateral end regions to form commissural joints, with the unattached edges forming the coaptation edges of the valve. The leaflets are affixed
to a skirt, which in turn can be attached to the frame. The upper ends of the commissure points define an outflow or proximal portion of the valve prosthesis. The opposite end of the valve at the skirt defines an inflow or distal portion of the valve prosthesis. The enlarged lateral end regions of the leaflets permit the material to be folded over to enhance durability of the valve and reduce stress concentration points that could lead to fatigue or tearing of the leaflets. The commissural joints are attached above the plane of the coaptation edges of the valve body to minimize the contacted delivery profile of the valve prosthesis. The base of the valve leaflets is where the leaflet edges attach to the skirt and the valve frame.

Referring now to <FIG>, frame <NUM> is an exemplary aspect of the present invention. Frame <NUM> includes inflow section <NUM>. valve section <NUM>, and outflow section <NUM>. Frame <NUM> also includes a plurality of cells in inflow section <NUM> and valve section <NUM> that can be different sizes and/or shapes.

The cell pattern permits frame <NUM> to expand to the shape depicted in <FIG>, having a conical inflow section <NUM>, an approximately constant diameter valve section <NUM>, and an increased diameter conical outflow section <NUM>. Frame <NUM> has a total height H10 of approximately <NUM> to approximately <NUM>. In the expanded configuration, the maximum diameter of inflow section <NUM>, D20 shown in <FIG>, can range from about <NUM> to about <NUM>, with a preferred range of about <NUM> to about <NUM>. Inflow section <NUM> also has a height H20 of approximately <NUM> to approximately <NUM>. The diameter of valve section <NUM>, D30 shown in <FIG>, can range from about <NUM> to about <NUM>, with a preferred range of about <NUM> to about <NUM>. Valve section <NUM> also has a height H30 of approximately <NUM> to approximately <NUM>. The maximum diameter of outflow section <NUM>, D40 shown in <FIG>, can range from about <NUM> to about <NUM>, with a preferred range of about <NUM> to about <NUM>. Outflow section <NUM> also has a height H40 of approximately <NUM> to approximately <NUM>. At the transition between inflow section <NUM> and valve section <NUM>, frame <NUM> can have a reduced diameter that is smaller than the diameter of valve section <NUM>. This reduced diameter is designed to abut the natural valve leaflets after valve prosthesis <NUM> is implanted. This reduced diameter also provides infolding resistance to the frame, allowing for uniform recapture of the device.

Each section of frame <NUM> in inflow section <NUM> and valve section <NUM> has a substantially circular cross-section in the expanded configuration. However, the cell patterns of frame <NUM> permit frame <NUM> to adapt to the specific anatomy of the patient, thereby reducing the risk of valve prosthesis migration and reducing the risk of perivalvular leakage. In one aspect of the invention, inflow section <NUM> of valve prosthesis <NUM> is disposed in the aortic annulus of the patient's left ventricle while outflow section <NUM> is positioned in the patient's ascending aorta.

The conical shape of inflow section <NUM> is designed to form an interference fit with the native valve annulus. The smooth transition from inflow section <NUM> to valve section <NUM> is designed to direct blood flow through the valve body with little or no turbulence. Typically, heart valve prostheses aim to create laminar blood flow through the prosthesis in order to prevent lysis of red blood cells, stenosis of the prosthesis, and other thromboembolic complications. Outflow section <NUM> is designed to conform to a patient's anatomy and to anchor valve prosthesis <NUM> in the patient's ascending aorta to prevent lateral movement or migration of valve prosthesis <NUM> due to normal movement of the heart. Outflow section <NUM> includes outflow loops <NUM>. Each outflow loop <NUM> is made up of struts 60a and 60b. Struts 60a and 60b come together at edges <NUM>, the proximal most portions of outflow loops <NUM>. Struts 60a and 60b each have proximal concave curves 62a and 62b, respectively, and distal convex curves 64a and 64b, respectively. It is understood that in most embodiments, struts 60a and 60b are made from a unitary laser cut tube of self-expanding metal. In one aspect of the invention, edges <NUM> are curved. In alternate an alternate aspect of the invention, edges <NUM> can be straight or angular.

Outflow loops <NUM> are attached to each other and to valve section <NUM> at junctions <NUM>. Each junction <NUM> is made up of a strut 60b from an outflow loop <NUM>, strut 60a from an adjacent outflow loop <NUM>, and a proximal edge <NUM> of a cell <NUM> from valve section <NUM>. In a preferred embodiment, junctions <NUM> are not formed on circumferentially adjacent cells <NUM> in valve section <NUM>. For example, at least one cell <NUM> can be positioned between circumferentially adjacent junctions <NUM>. In an alternate aspect of the invention, two or more cells <NUM> can be positioned between circumferentially adjacent junctions <NUM>. In one aspect of the invention, proximal edges <NUM> of cells <NUM> that are not connected at junctions <NUM> are angled inward toward the center of frame <NUM> at an angle A30. Angle A30 can be approximately <NUM> degrees to approximately <NUM> degrees. In a preferred embodiment, angle A30 is approximately <NUM> degrees. Angle A30 helps to retain the valve prosthesis on the delivery system in the collapsed configuration and helps to prevent vascular injury when the valve prosthesis is in the expanded configuration.

Struts 60a and 60b extend outward from junction <NUM> at an angle A60, shown in <FIG>. In one aspect of the invention, angle A60 can be approximately <NUM> degrees to approximately <NUM> degrees. In a preferred embodiment, angle A60 is <NUM> degrees. Edge <NUM> at the proximal end of struts 60a and 60b can be bent at an angle A70 with respect to the direction of blood flow. In one aspect of the invention, angle A70 can be approximately <NUM> degrees outward from the center of frame <NUM> or <NUM> degrees inward towards the center of frame <NUM>, as shown in <FIG>. In a preferred embodiment, angle A70 is <NUM> degrees inward towards the center of frame <NUM>. Angle A70 is provided to prevent injury to the ascending aorta.

Referring now to <FIG>, valve prosthesis <NUM> includes frame <NUM> and valve <NUM>. Valve <NUM> includes leaflets <NUM> and commissure points <NUM>. Commissure points <NUM> are attached to cells of frame <NUM> in valve section <NUM>. The object of the present valve prosthesis is to mimic the native valve structure. This valve design provides several advantages over other percutaneously delivered replacement valve prostheses. For example, because the diameter of frame <NUM> in valve section <NUM> is approximately constant, commissure points <NUM> can be attached to cells of frame <NUM> that are approximately parallel to the direction of flow. For example, angle A120 is approximately <NUM> degrees. This alignment increases the spacing between commissure points <NUM> and the sinotubular junction which reduces the risk of a coronary occlusion. In addition, the parallel alignment of commissure points <NUM> along with the size of outflow loops <NUM> allow a clinician to readily gain access to the coronary arteries, for example, to perform angioplasty or stenting, simply by directing the angioplasty or stent delivery system guidewire through outflow loops <NUM>.

This alignment also reduces stress on commissure points <NUM> and valve <NUM> as compared to valve prostheses that include a frame that is angled outward from the center of frame at the commissure attachment points. In an alternate aspect of the invention, the diameter of valve section <NUM> of frame <NUM> can be reduced in the region where commissure points <NUM> attach to frame <NUM>. In this configuration, commissure points <NUM> can be angled inward towards the center of frame <NUM>. In an alternate aspect of the invention, the diameter of valve section <NUM> can be increased in the region where commissure points <NUM> attach to frame <NUM>. In this configuration, commissure points <NUM> can be angled outwards from the center of frame <NUM>. Consequently, angle A120 can range from approximately <NUM> degrees outward from the center of the frame to approximately <NUM> degrees inward towards the center of the frame, as shown in <FIG>.

In addition, the approximately constant diameter of frame <NUM> through valve section <NUM> provides for a reduced force required to crimp valve prosthesis <NUM> for delivery into the patient's heart, as compared to prior art valve prostheses. Such a configuration also reduces the strain on frame <NUM> in the collapsed configuration.

An additional advantage of this frame design is the ability to isolate deformation caused by positioning of the valve prosthesis in situ along different portions of frame <NUM>. As discussed above, outflow section <NUM> is composed of a plurality of outflow loops <NUM> and junctions <NUM> are not present on circumferentially adjacent cells <NUM> of valve section <NUM>. Therefore, outflow loops <NUM> span at least one cell <NUM> of valve section <NUM> in a circumferential direction and have a limited number of junctions <NUM> which connect outflow section <NUM> to valve section <NUM>. Accordingly, the amount of frame material that makes up outflow section <NUM> is reduced, as compared to a frame where the cellular structure extends circumferentially throughout the entire frame. This reduction in material along with the reduced number of connections between outflow section <NUM> and valve section <NUM> allows outflow section <NUM> to be flexible and provides for a more distal bending point on frame <NUM>. This provides for reduced transmission of the deformation along frame <NUM>, allowing valve section <NUM> to maintain a circular shape in situ.

In a typical heart <NUM>, shown in <FIG>, aorta <NUM> has an aortic axis <NUM>. Aorta <NUM> also contains a native valve <NUM> and a sinus axis <NUM>. Sinus axis <NUM> is offset from aortic axis <NUM> such that aortic axis <NUM> and sinus axis <NUM> are not parallel. This offset is shown in the X-Y plane in <FIG>, and is represented as angle <NUM>. The aorta is an asymmetric structure and the aortic axis and sinus axis can also be offset in the Y-Z and X-Z planes.

As discussed above, outflow section <NUM> anchors valve prosthesis <NUM> in the patent's ascending aorta. The aorta deforms outflow section <NUM> which can transmit a force along frame <NUM>. It is the inventors understanding that prior art frame structures are rigid along the entire frame from the outflow to the inflow portion of the frame, causing this force to deform the entire frame structure. Such deformation along the entire frame prevents the frame from properly aligning on either the aortic axis or the sinus axis. To address this issue, in one aspect of the disclosure, the structure and flexibility of frame <NUM>, particularly in outflow section <NUM>, provides a more distal bending point on the frame to allow valve section <NUM> to align on sinus axis <NUM> during deployment, while outflow section <NUM> simultaneously aligns on aortic axis <NUM>. Because valve section <NUM> is aligned on sinus axis <NUM>, valve <NUM> is able to form a competent seal with the native valve <NUM> which reduces leakage around valve prosthesis <NUM>. In effect, the present frame design creates two tubular structures, as shown in <FIG>. First tubular structure <NUM> includes inflow section <NUM> and valve section <NUM>. Second tubular structure <NUM> includes outflow section <NUM>. The proximal most portion of first tubular structure <NUM> is attached to the distal most portion of second tubular structure <NUM> at junctions <NUM>. Junctions <NUM> create a flexible juncture between the tubular structures allowing first tubular structure <NUM> to align with sinus axis <NUM> while second tubular structure <NUM> aligns with the aortic axis <NUM>. After implantation in a patient, first tubular structure <NUM> can be offset from second tubular structure <NUM> in the axial direction.

In addition, the forces exerted by the aorta on a valve prosthesis create pressure that is transmitted from the outflow portion of the frame to the inflow portion of the frame located near the left bundle branch. This pressure can cause conduction disturbances in the left bundle branch resulting in the need for a patient to receive a permanent pacemaker. The flexibility and structure of outflow section <NUM> absorbs the forces exerted by the aorta on frame <NUM>. This design reduces the pressure exerted by the aorta along valve prosthesis <NUM> and can prevent the need for a pacemaker in the patient. In particular, the flexible juncture between first tubular structure <NUM> and second tubular structure <NUM> prevent forces exerted on second tubular structure <NUM> from transferring to first tubular structure <NUM>.

Prior art valve prostheses typically have eyelets to attach the valve prostheses to a delivery system. The eyelets attach to tabs which retain the valve prosthesis. However, the attachment between the eyelets and the tabs provides minimal clearance when the valve prosthesis is deployed. As a result, the geometry of the attachment mechanism and the torque generated by advancing the delivery system around the curvature of the aortic arch can cause the valve to lock with the delivery system preventing full deployment of the valve prosthesis in the patient's heart. This is especially a problem when after delivery, one of the tabs remains pressed against the aortic wall. When this occurs, there can be insufficient clearance for the eyelet to fully detach from the tabs and delivery system. To release the valve, the delivery system must be moved and turned which can interfere with the correct positioning of the valve prosthesis.

In addition, delivery systems typically include an outer sheath or capsule that surrounds the collapsed valve prosthesis during delivery to the implantation site. During deployment, the capsule is withdrawn over the valve prosthesis. The friction between the capsule and the valve prosthesis during capsule withdrawal imposes an axial force along the valve prosthesis which can cause the valve prosthesis to improperly migrate on the delivery system. Accordingly, the delivery system must have sufficient structure to hold the valve prosthesis in place and to resist the axial force created by withdrawal of the capsule during deployment of the valve prosthesis.

Frame <NUM> provides an integrated attachment system that ensures the full release of valve prosthesis <NUM> from the delivery system. The design utilizes the self-expanding nature of the frame to detach the valve prosthesis from the delivery system. In the collapsed configuration, frame <NUM> forms an attachment to the delivery system. When the frame expands, the attachment is no longer present.

Referring now to <FIG>, the delivery system for valve prosthesis <NUM> includes catheter assembly <NUM> that includes an outer sheath <NUM>, a pusher tube <NUM>, and a central tube <NUM>, each of which are concentrically aligned and permit relative motion with respect to each other. At a distal end of pusher tube <NUM> is a capsule <NUM>. At a distal end of central tube <NUM> is plunger assembly <NUM>. Capsule <NUM> surrounds plunger assembly <NUM> during delivery of valve prosthesis <NUM>. Plunger assembly <NUM> includes hub <NUM> at a proximal end and tip <NUM> at a distal end. The diameter of hub <NUM> is larger than the diameter of section <NUM>. The step change at edge <NUM> is provided to abut the proximal edges <NUM> of cells <NUM> in valve section <NUM> in the collapsed configuration. During capsule withdrawal, edge <NUM> will apply back pressure to proximal edges <NUM> of cells <NUM> to prevent migration of the valve prosthesis on the delivery system. In the collapsed configuration, angle A30 of cells <NUM> further helps to maintain engagement with edge <NUM> during deployment of the valve prosthesis. Tip <NUM> facilitates the advancement of catheter assembly <NUM> through the patient's vasculature. Hub <NUM> includes one or more tabs <NUM> for retaining valve prosthesis <NUM> on plunger assembly <NUM>. Tabs <NUM> also prevent the pre-release of valve prosthesis <NUM> and assist in retaining valve prosthesis <NUM> during recapture. The top surface of tabs <NUM> interact with the inner surface of capsule <NUM> to form an interference fit.

<FIG> and <FIG> show collapsed valve prosthesis <NUM> attached to plunger assembly <NUM>. In a collapsed configuration, the circumferential distance between concave curves 62a and 62b on struts 60a and 60b of outflow loops <NUM> is reduced to form attachment loops <NUM> between concave curves 62a and 62b and edge <NUM>. In one aspect of the invention, concave curves 62a and 62b on struts 60a and 60b on collapsed valve prosthesis <NUM> touch to form a closed attachment loop. This closed attachment loop increases the column strength of outflow section <NUM> in the collapsed configuration, as compared to when concave curves 62a and 62b do not touch. This increased column strength can be required to prevent outflow section <NUM> from buckling during withdrawal of capsule <NUM> during delivery of valve prosthesis <NUM>. Alternatively, a gap can be present between concave curves 62a and 62b on struts 60a and 60b on collapsed valve prosthesis <NUM>. Tabs <NUM> on plunger assembly <NUM> engage attachment loops <NUM> during delivery of valve prosthesis <NUM>. Capsule <NUM> surrounds plunger assembly <NUM> and collapsed valve prosthesis <NUM> and restrains valve prosthesis <NUM> in the radial direction. The engagement between tabs <NUM> and attachment loops <NUM> prevents migration of valve prosthesis <NUM> on plunger assembly <NUM> in the axial direction. For example, the engagement between tabs <NUM> and attachment loops <NUM> can prevent pre-release of valve prosthesis <NUM> from the delivery system. This engagement can also allow for recapture of valve prosthesis <NUM> if valve prosthesis <NUM> needs to be repositioned. The interference fit between the top surface of tabs <NUM> and the inner surface of capsule <NUM> prevents attachment loops <NUM> from moving over tabs <NUM> and disengaging from plunger assembly <NUM>.

In one aspect of the invention, <FIG> shows frame <NUM> in the expanded configuration. In the expanded configuration, the circumferential distance between concave curves 62a and 62b is increased and concave curves 62a and 62b no longer form attachment loops with edges <NUM>. Accordingly, valve prosthesis <NUM> is disengaged from tabs <NUM> on the delivery system. In the expanded configuration of frame <NUM>, the attachment feature securing valve prosthesis <NUM> to the delivery system is no longer present. This design ensures that the valve can be fully released from the delivery system.

Referring now to <FIG>, tabs <NUM> on hub <NUM> can be teardrop shaped. In alternate aspects of the invention shown in <FIG>, the tabs may be any other shape known to a person of ordinary skill in the art. For example, tabs <NUM> are circular; tabs <NUM> are triangular, tabs <NUM> are rectangular, and tabs <NUM> are square. In one aspect of the invention, perimeter surface <NUM> on tabs <NUM> is flat and perpendicular to the direction of blood flow. In an alternate aspect, perimeter surface <NUM> of tabs <NUM> is a concave curve. In a further aspect of the invention, perimeter surface <NUM> of tabs <NUM> is a convex curve. The shape of the perimeter surface of the tabs can be optimized to allow edge <NUM> to clear the tabs during delivery system withdrawal, and to prevent edge <NUM> from slipping over the tabs prematurely. In addition, the front surface of the tabs can be flat. In an alternate aspect, the front surface of the tabs can be a convex curve.

<FIG> illustrate an alternate frame and delivery system design. As discussed above, a gap can be present between the concave curves and/or the convex curves of the struts of the frame in the collapsed configuration. As shown in <FIG>, struts 860a and 860b of outflow loops <NUM> do not touch in the collapsed configuration. Gap <NUM> is provided between struts 860a and 860b in the collapsed configuration. Shelf <NUM> is provided on hub <NUM> to prevent migration of valve prosthesis <NUM> on the delivery system during deployment. In the collapsed configuration, edge <NUM> of valve prosthesis <NUM> is secured between shelf <NUM> and tabs <NUM> on hub <NUM>. Shelf <NUM> applies back pressure to frame edge <NUM> during withdrawal of capsule <NUM> and deployment of the valve prosthesis <NUM>. Tabs <NUM> pull valve prosthesis <NUM> during recapture.

An alternate embodiment is shown in <FIG> shows hub <NUM> including a first row of tabs 924a and a second row of tabs 924b. Tabs 924b are provided to prevent migration of valve prosthesis <NUM> on the delivery system during deployment. For example, during withdrawal of the capsule, tabs 924b apply back pressure to junctures <NUM> on valve prosthesis <NUM>. Tabs 924b serve a similar function as shelf <NUM>, discussed above. In this embodiment, tabs 924a pull valve prosthesis <NUM> during recapture.

The valve prosthesis can replace the function of a tricuspid or bicuspid heart valve including the mitral valve, the aortic valve, the pulmonary valve, or the tricuspid valve. The valve can be delivered, for example, transfemorally, transeptally, transapically, transradially, or transatrially.

Implantation of the valve prosthesis will now be described. As discussed above, the valve prosthesis preferably comprises a self-expanding frame that can be compressed to a contracted delivery configuration onto an inner member of a delivery catheter. This frame design requires a loading system to crimp valve prosthesis <NUM> to the delivery size, while allowing the proximal end of valve prosthesis <NUM> to protrude from the loading system so that the proximal end can be attached to tabs <NUM>.

The valve prosthesis and inner member can then be loaded into a delivery sheath of conventional design, e.g., having a diameter of less than <NUM>-<NUM> French. Due in part to the fact that the commissure points are longitudinally offset from the coaptation edges of the leaflets, and due to the ability to maintain a lower commissure height, it is expected that the valve prosthesis can achieve a significantly smaller delivery profile than previously-known percutaneously-deliverable replacement valves.

The delivery catheter and valve prosthesis can then be advanced in a retrograde manner through the femoral artery and into the patient's descending aorta. The catheter then is advanced, under fluoroscopic guidance, over the aortic arch, through the ascending aorta and mid-way across the defective aortic valve. Once positioning of the catheter is confirmed, capsule <NUM> can be withdrawn proximally, thereby permitting valve prosthesis <NUM> to self-expand.

As the valve prosthesis expands, it traps the leaflets of the patient's defective aortic valve against the valve annulus, retaining the native valve in a permanently open state. The outflow section of the valve prosthesis expands against and aligns the prosthesis within the ascending aorta, while the inflow section becomes anchored in the aortic annulus of the left ventricle, so that the skirt reduces the risk of perivalvular leaks.

Alternatively, the valve prosthesis can be delivered through a transapical procedure. In a transapical procedure, a trocar or overtube is inserted into the left ventricle through an incision created in the apex of a patient's heart. A dilator is used to aid in the insertion of the trocar. In this approach, the native valve (e.g. the mitral valve) is approached from the downstream relative to the blood flow. The trocar is retracted sufficiently to release the self-expanding valve prosthesis. The dilator is preferably presented between the valve leaflets. The trocar can be rotated and adjusted as necessary to properly align the valve prosthesis. The dilator is advanced into the left atrium to begin disengaging the proximal section of the valve prosthesis from the dilator.

Claim 1:
A valve prosthesis (<NUM>) comprising:
a valve body (<NUM>) including a plurality of valve leaflets (<NUM>) affixed to a skirt; and
a frame (<NUM>) including a distal inflow section (<NUM>), a proximal outflow section (<NUM>), and a valve section (<NUM>) between the inflow section (<NUM>) and the outflow section (<NUM>), wherein:
the valve body (<NUM>) is attached to the frame (<NUM>) in the valve section (<NUM>) at a plurality of commissure points (<NUM>),
the frame (<NUM>) includes a circumferentially repeating cell pattern in the inflow section (<NUM>) and the valve section (<NUM>),
the outflow section (<NUM>) includes a plurality of loops (<NUM>), the loops (<NUM>) being attached to the valve section (<NUM>) at a plurality of junctions (<NUM>), and
a plurality of valve section cells are positioned between each junction (<NUM>) in a circumferential direction; and wherein:
each loop includes a first strut (60a) and a second strut (60b) joined proximally at a loop edge (<NUM>), a first junction (<NUM>), and a second junction (<NUM>),
the first junction (<NUM>) connects a first loop and a second loop to the valve section (<NUM>), the first junction (<NUM>) includes a first proximal valve section cell edge, a second strut from the first loop, and a first strut from the second loop, and
the second junction (<NUM>) connects the second loop and a third loop to the valve section (<NUM>), the second junction (<NUM>) includes a second proximal valve section cell edge, a second strut from the second loop, and a first strut from the third loop.