WO2015123607A2

WO2015123607A2 - Temporary sub-valvular check valve

Info

Publication number: WO2015123607A2
Application number: PCT/US2015/015965
Authority: WO
Inventors: Ivan Vesely; Clayton COLE
Original assignee: Valvexchange, Inc.
Priority date: 2014-02-13
Filing date: 2015-02-13
Publication date: 2015-08-20
Also published as: WO2015123607A3

Abstract

A check valve has a mesh frame structure, an expandable seal ring, and a plurality of sleeve strips positioned in and attached to the interior of the frame structure. The check valve can be introduced along a tool shaft, between the tool shaft and a sheath, for positioning in a chamber or vasculature. Removal of the sheath allows a shape memory alloy mesh forming the frame structure to expand and press the seal structure against an adjacent wall. Cardiac function is augmented during valve replacement procedures, such as valve excision, valve implantation, or valve leaflet replacement, by placing the temporary check valve just upstream of the valve being treated. The check valve is collapsible to be inserted through a small incision in the apex of the heart or through the aorta into the ventricular cavity and re-collapsed by retraction within the sheath for removal after the procedure.

Description

TEMPORARY SUB-VALVULAR CHECK VALVE

INVENTORS

Ivan Vesely of Larkspur, Colorado

Clayton Cole of Boulder, Colorado

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority pursuant to 35 U.S.C. § 1 19(e) of U.S. provisional application no. 61/939,587 filed 13 February 2014 entitled "Temporary sub- valvular check valve," which is hereby incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with government support under contract number 8RHL099059B awarded by National Institutes of Health. The government has certain rights in the invention.

FIELD OF TECHNOLOGY

[0003] The present disclosure relates generally to a system for performing procedures on native or prosthetic heart valves, and more particularly to the servicing, repair, or replacement of heart valves without requiring cardiopulmonary bypass.

BACKGROUND

[0004] The demographics of patients suffering valvular disease are broad and the treatment modalities for each are complex. Historically, patients younger than 65 years of age have been prescribed mechanical valves and those older receive bioprosthetic valves. These prosthetic valves eventually wear out and need to be replaced with a new, functional device.

[0005] Replacement of native or prosthetic valves has traditionally required open-chest, open-heart surgery in which the patient is placed on cardiopulmonary bypass and the heart stopped and restarted again after the surgery is completed. Cardiopulmonary bypass, however, is associated with both short-term and long-term complications, such as cognitive impairment. This apparently results from the low-grade damage that occurs to the blood cells as they pass through the heart-lung machine. Although not completely understood, the process of subjecting blood constituents to pumps and oxygenators leads to the formation of small clots which then cause micro-strokes when introduced back into the patient. [0006] Performing off-pump, beating-heart surgery has been a great challenge and an important objective for surgeons for many decades; the most successful today is the surgical repair of atherosclerotic lesions in the coronary arteries. Off-pump Coronary Artery Bypass Surgery (OP-CABG) is now considered a huge advantage for patients that require Coronary Artery Bypass. Although the chest is opened to allow access to the surface of the heart, the heart continues to pump as the blood vessels that feed blood to the heart are repaired and bypassed.

[0007] Surgery on other components of the heart, such as the valves of the heart, is more difficult. This is because the valves are inside the heart and opening the heart to expose them cannot be done with the heart pumping blood. The primary candidate technology for treating heart valves without stopping the heart and opening it up is the use of catheter-implantable valves. These valves are delivered through a catheter passed up through the aorta or the aortic arch, or through the apex of the heart into the ventricular cavity. These valves consist of tissue leaflets mounted on a frame that is expanded and anchored in the vicinity of the existing diseased native valve.

[0008] Transcatheter Aortic Valve Implantation (TAVI) has become very popular because it avoids the potential complications of opening up the chest and placing the patient on cardiopulmonary bypass. This new technology is thus used on the very old or sick patients that have a high risk of dying if they were to undergo conventional open-heart surgery on cardiopulmonary bypass.

[0009] The challenge in performing TAVI is the need to perform the procedure quickly. During the procedure itself, the native heart valve is crushed against the sides of the aorta, and during that process, the patient is essentially without a valve and thus without normal cardiac output flow. Moreover, many current generation transcatheter valves are expanded and seated in place by way of a balloon which occludes the aorta, essentially preventing any ejection of blood from the heart. To enable the balloon and the associated transcatheter valve from being ejected out of the heart, the physician rapidly paces the heart, dramatically reducing its contractions and preventing the pumping of blood. This is not an ideal situation for the patient, particularly if they are already ill and compromised from the underlying valvular disease.

[0010] Another approach has been to augment the native valve with a temporary valve to augment the pumping of blood while the native valve is in the process of being repaired, excised, or replaced with a prosthetic valve.

[0011 ] Prior temporary check valves have been placed in the ascending or descending aorta. This is not an ideal location, since the temporary valve is downstream from the coronary arteries and does not function in the appropriate manner during diastole to help in the filling of the coronary arties, as with the native aortic valve. [0012] There is also a situation when the native valve has already been replaced with a prosthetic device, and that device itself needs replacement. One such technology is the exchangeable valve concept (disclosed, for example, in U.S. Patent No. 7,01 1 ,681 B2), in which the old, worn-out leaflet set may be pulled off the base of the valve and replaced with a new one. Such a procedure may also benefit from the use of an appropriate temporary check valve.

[0013] The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded as subject matter by which the scope of the invention is to be bound.

SUMMARY

[0014] The technology presented herein is a system for augmenting cardiac function during valve procedures, such as valve excision, valve implantation, or valve leaflet replacement, by placing a temporary check valve just upstream of the valve being treated. The temporary check valve is collapsible so that it can be inserted through a small incision or port in the apex of the heart or through the aorta, into the ventricular cavity. Such a system thus does not require arrest or pacing of the heart and will allow such valve repair or replacement procedures to be done without concern for time or compromise to the patients' physiology.

[0015] In procedures on the aortic valve, a better location for the temporary check valve is upstream of the native aortic valve or essentially inside the ventricle, yet in intimate contact with the aortic outflow tract. Having the temporary check valve upstream of the coronary arteries, and upstream of the native valve, will enable procedures to take place on the native aortic valve and still facilitate the proper ejection of blood from the ventricle and the filling of the coronary arteries in a physiologically appropriate manner.

[0016] A further application of the temporary check valve is in conjunction with the placement of a valve-supporting frame without the leaflets. The valve supporting frame can be incrementally dilated until it fits snugly in the patient's aortic root and the appropriately sized leaflets that fit into that frame can then be delivered. During the positioning and expansion of the frame, the patient may be without a fully functioning valve. The temporary check valve may thus help provide continuous cardiac output until the final leaflet set is delivered onto the valve frame.

[0017] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. A more extensive presentation of features, details, utilities, and advantages of the present invention as defined in the claims is provided in the following written description of various embodiments of the invention and illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 A is a schematic side isometric view of an extended temporary check valve in closed position and mounted on a tool shaft passed into the interior of the heart.

[0019] FIG. 1 B is a cross sectional view of the temporary check valve of FIG. 1 A as indicated by line 1 B-1 B.

[0020] FIG. 2A is a schematic side isometric view of an extended temporary check valve in open position.

[0021] FIG. 2B is a cross sectional view of the temporary check valve of FIG. 2A as indicated by line 2B-2B.

[0022] FIG. 3 is an isometric view of the temporary check valve of FIG. 1 A shown in vivo placed in the ventricle below the aortic valve.

[0023] FIG. 4A is a schematic side isometric view of the temporary check valve of FIG. 2A positioned below a valve frame of a two-part valve system.

[0024] FIG. 4B is a cross sectional view of the temporary check valve and prosthetic device of FIG. 4A.

DETAILED DESCRIPTION

[0025] A temporary vascular check valve 100 that can be positioned upstream within a vascular structure, below an existing valve, e.g., below the aortic valve 182 in the heart 174, and augment the function of the original valve is disclosed herein in conjunction with the accompanying figures. FIG. 3 is provided as reference to indicate an exemplary use of the vascular check valve 100 within the left ventricle 178 in the heart 174. As used herein, the term "vascular structure" is meant to include the heart 174 and structures thereof as well as blood vessels generally.

[0026] According to a first implementation, and as can be seen in FIGS. 1 A-2B, a temporary check valve 100 is formed primarily as a stent-like frame structure 106 and a flow restrictive sleeve 108 positioned within the interior of the frame structure 106. The frame structure 106 may formed as a mesh or cage and be understood to have three primary sections: a distal barrel section 103, an intermediate funnel section 104, and a proximal collar section 126. The barrel section 103 may be cylindrical in shape. The funnel section 104 may be formed as a frustum that transitions at its largest diameter into the barrel section 102. The collar section 126 may by formed as a smaller diameter cylindrical shape that transitions from the smallest diameter of the funnel section 104. A seal ring 122 may be provided on a distal end 1 12 of the barrel section 102. A collar 142 may be provided on the proximal end of the frame structure 106 to retain the collar section 126 at the relatively smaller diameter.

[0027] A sleeve 108 formed from multiple annular sleeve strips 1 10 of a thin, flexible material may be attached to the interior surface of the frame structure 106 along the barrel section 102 and the funnel section 104. In the barrel section 102, multiple annular sleeve strips 1 10 may be attached to the frame structure 106 along only the distal edges. The proximal edges of the sleeve strips 1 10 are free. Each of the sleeve strips 1 10 in the barrel section 102 is positioned such that the proximal edges slightly overlap the distal edges of adjacent sleeve strips 110. The bottom edge of the most proximal sleeve strip 1 10 in the barrel section 102 overlaps the distal edge of the funnel strip 1 18 lining the funnel section 104. The funnel strip 1 18 may be formed as a frustum wall and may be attached to the frame structure 106 at both the proximal and distal edges.

[0028] The check valve 100 in FIG. 1 A and 1 B is shown mounted on an

insertion/positioning tool shaft 160, and partially within an introducer sheath 164. The proximal end 1 12 of the check valve 100 in FIGS. 1 A-2B is shown emerging from the introducer sheath 164 that aids in maintaining the check valve 100 in a compressed configuration, such as when the check valve 100 is inserted into the patient, or when the check valve 100 is no longer needed and is being removed. At the distal end 1 12, near the seal ring 122, the check valve 100 is uncompressed, having fully emerged from the introducer sheath 164.

[0029] The check valve 100 is designed to expand when positioned within a patient. FIGS. 1 A-2B show the check valve 100 in its expanded configuration. The frame structure 106 of the check valve 100 is designed to expand until it either reaches a predetermined size or until it contacts a surface within the patient (for example a blood vessel wall or ventricle wall 170). The frame structure 106 is maintained in the compressed configuration by being sandwiched between the tool shaft 160 and introducer sheath 164. As described in more detail below, the frame structure 106 may be made of a shape memory alloy that expands at body temperatures. While FIGS. 2A-2B do not show the introducer sheath 164 or the tool shaft 162, these structures would be present in practice to maintain the proximal end 1 12 of the check valve 100 in its compressed configuration.

[0030] In the expanded configuration, the frame structure 106 defines an interior diameter, D, at the distal end 1 12 that is greater than the interior diameter d defined at its proximal, compressed end. The diameter of the proximal end, d, is selected to aid in mounting the check valve 100 on the tool and inside the introducer sheath 164.

Compression aids in inserting the check valve 100 into a patient and positioning the check valve 100 for deployment. In the compressed configuration, the check valve 100 is positioned between the exterior surface of the tool and an interior surface of the introducer sheath 164.

[0031] The check valve 100 embodiment of FIGS. 1 A-2B defines three segments: a proximal collar section 126, a distal barrel section 102, and a funnel section 104 positioned between the barrel section 102 and collar section 126. In this embodiment, the barrel section 102 has an expanded configuration, the collar section 126 has a compressed configuration, and the funnel section 104 has an intermediate configuration between the compressed and expanded configurations.

[0032] In some embodiments, a sliding collar 124 may be positioned at the proximal end of the check valve 100 adjacent the collar section 126. The sliding collar 124 may help position the check valve 100 along the length of the insertion and guide tool and/or may aid in pushing the check valve 100 out beyond the introducer sheath 164. The check valve 100 can be repositioned along the tool shaft 160 with a control structure, for example, sliders or pull wires that are attached directly to the frame or indirectly via the sliding collar 124. The tool shaft 160 may facilitate the insertion or action of additional tools and may thus move along its axis further into the heart, independent of the check valve 100.

Open and Closed Configurations

[0033] The check valve 100 may be positioned near a valve being replaced or repaired, with the distal end 1 12 of the check valve 100 positioned nearest that valve. At this position, the check valve 100 is designed to prevent blood from flowing through the damaged or absent valve into the area behind the check valve 100 (e.g., the left ventricle 178, when the damaged valve is the aortic valve 182). This direction of blood flow may be termed retrograde or reverse direction blood flow, and occurs, for example, when the ventricle 178 relaxes in diastole and the pressure within the ventricle 178 drops. When the check valve 100 prevents reverse blood flow, it is said to be in the "closed position," which is depicted in FIGS. 1 A and 1 B.

[0034] During ventricular contraction, or systole, the check valve 100 is designed to allow blood to flow freely through the frame structure 106. This direction of blood flow is termed the forward direction.

[0035] The sleeve structure 108 helps regulate blood flow through the check valve 100. The sleeve 108, as shown in FIGS. 1 A-2B comprises a plurality of sleeve strips 1 10 arranged as adjacent cylindrical sections along the inner surface of the frame structure 106 from the proximal end 1 14 to the distal end 1 12 of the frame structure 106. In some embodiments, the proximal edge of each sleeve strip 1 10 may overlap with the distal edge of the adjacent sleeve strip 1 10 proximal to it. The sleeve strips 110 may be made of any suitable material that is flexible and appropriate for use in the human body. The material may be natural or synthetic, for example, pericardium or polyurethane.

[0036] Each sleeve strip 1 10 is secured to the interior surface of the frame structure 106 along an inner circumference at the distal edge of the sleeve strip 1 10. The sleeve strips 1 10 may be secured by sutures or pins. The proximal edge of each sleeve strip 1 10 remains unsecured. The distal-most strip 1 16 may alternatively be attached to the seal ring 122 to prevent gaps. The funnel strip 1 18, shown in FIGS. 1 A-2B positioned at or near the proximal collar section 126 is attached to the frame structure 106 at its proximal edge and/or its proximal edge remains sandwiched between an outer surface of the tool 160 and an inner surface of the introducer sheath 164.

[0037] The closed position of the check valve 10Ois depicted in FIGS. 1 A and 1 B. In this position, each sleeve strip 1 10 is pressed against the interior surface of the frame structure 106 and its proximal edge overlaps the adjacent proximal sleeve strip 1 10. Overlap may be up to 25%-50%. This arrangement of sleeve strips 1 10 seals the check valve 100 and prevents blood flowing from the interior 120 of the check valve 100, through the frame structure 106 and into the space behind the check valve 100 (e.g., the ventricular cavity).

[0038] The open position is depicted in FIG. 2A-B. In this position, the unsecured proximal edges of the sleeve strips 1 10 are free to move with the blood flowing through the frame structure 106 into the interior 120 of the check valve 100. When blood flows in the forward direction, toward the distal end 1 12 of the check valve 100, it passes through the frame structure 106 from the exterior to the interior 120 and, because each sleeve strip 1 10 is secured only at its distal end, the sleeve strips 1 10 are free to move with the blood flow and the blood can flow through the frame structure 106 and between the sleeve strips 1 10.

Seal Ring Structure

[0039] The annular seal ring 122, which is positioned at the distal end 1 12 of the frame structure 106, is generally circular in shape. The seal ring 122 is generally flexible and can increase or decrease its circumference and diameter as necessary. A toroidal balloon is one possible embodiment of such an annular seal ring 122. The balloon can be inflated with saline, as is done in other balloon applications. A tube for inflating the balloon is not shown in the figures, but can run through the interior or exterior of the frame structure 106, and can run along the outside or inside the tool shaft 160, or can be incorporated into the wall material of the tool shaft 160. As is customary in the field, these components may be made of molded or extruded plastic. In other embodiments, the annular seal ring Ί 22 may be an elastomeric structure such as an O-ring that is able to expand and contract to follow the varying diameters of the frame structure 106. [0040] The presently disclosed check valve 100 can be designed to mate with a variety of bioprosthetic devices. In one implementation, the seal structure may be designed to mate with the underside or base wall 154 of an existing bioprosthetic valve 150, as well as against the inner surface of a blood vessel or areas of the heart 174 such as in or near the aortic root to displace the native aortic valve leaflets. In some embodiments, the seal ring 122 is designed to be inserted into a bioprosthetic valve 150 and dilated until it fits snugly within the base wall 154 of the bioprosthetic valve 150. One embodiment of the check valve 100 seal ring 122 inserted into the bioprosthetic valve 150 is shown in FIGS. 4A-B. FIGS. 4A-B show the seal ring 122 in contact with one possible bioprosthetic valve 150, here a valve frame 152 of a two-part valve system. Then an appropriately sized leaflet set may then be snapped in place to repair or complete the bioprosthetic valve 150.

Frame Structure

[0041] The frame structure is manufactured of a collapsible mesh. In most

embodiments, the collapsible mesh may be made of a biocompatible metal or polymer. In one embodiment, the collapsible mesh is made from a shape memory metal alloy, for example, shape memory alloys comprising nickel and titanium such as Nitinol, and is configured to expand radially to form a larger circumference when exposed to body temperature. In some embodiments, as shown in FIGS. 1 A-2B, the frame structure is a diamond-shaped collapsible mesh that may be compressed and expanded radially. When in a compressed state, the length of the frame structure 106 may be longer than the length of the frame structure 106 when it is in the radially expanded state.

[0042] In the embodiment depicted in FIGS. 1 A-2B, the collapsible mesh is compressed circumferentially at the collar section 126 by a introducer sheath 164. When the introducer sheath 164 is retracted or the frame structure is advanced beyond the introducer sheath 164, the frame will expand circumferentially until it achieves an expansion limit or presses against another structure, for example the walls of the ventricle 178 or of a blood vessel. The barrel section 102 shown in FIGS. 1 A-2B shows the frame structure at its expansion limit. The collapsible mesh at the funnel section 104 has an intermediate compression level. The shape shown in FIGS. 1 A-2B may be a predetermined shape. Alternatively, the shape of the check valve 100 may result from the collar section 126 being constrained by the introducer sheath 164, such that if the collar section 126 were released from the introducer sheath 164 its interior diameter would be similar to that of the barrel section 102.

[0043] The seal structure may be dilated in conjunction with or independently of the frame structure 106. When the check valve 100 is in the closed position, the sleeve strips 1 10 press against the interior surface of the frame structure 106 and are supported by the mesh to form a seal against back pressure. In most embodiments, the shape of the sleeve strip 1 10 conforms to the shape of the mesh. For example, the sleeve 108 at the funnel section 104 may comprise a cone-shaped funnel strip 1 18 to conform to the shape of the expanded mesh in this section. The unsecured proximal edges of the sleeve strips 1 10 project proximally toward the collar section 126 to overlap the distal edge of the adjacent, proximal sleeve strip 1 10. This overlap, which may be up to about 25-50%, helps to seal the check valve 100 so that there are no gaps between sleeve strips 1 10 and leakage is prevented. The closed position of the check valve 100 prevents the flow of fluid back through the temporary check valve 100 into the left ventricle 178 chamber of the heart 174 during ventricular diastole.

[0044] The shape and size of the expanded mesh is designed to allow the sleeve strips 1 10 to be made very thin and collapsible, sleeve strips 1 10 may be thin biological or synthetic sheets, for example, pericardium or polyurethane, that can easily fold up when the check valve 100 is compressed within the introducer sheath 164. Without the mesh of the frame structure 106 supporting the sleeve strips 1 10 in the closed configuration, the sleeve strips 1 10 would need to be stiffer and stronger in order to bear the force of the fluid pressure. The distal edges of the sleeve strips 1 10 can be attached to the frame

structure 106 by way of sutures, pins, or any other suitable method. In some embodiments, for example where the frame structure 106 and sleeve strips 1 10 are made of synthetic (e.g., polymer) materials, the sleeve strips 1 10 can be overmolded over portions of the frame structure 106. In other embodiments, the distal edges of the sleeve strips 1 10 may be formed on or attached to a flexible wire loop, which is in turn attached to the frame structure 106. The wire loop may be used to provide additional structure to each sleeve strip 1 10 and help maintain the circular form.

Check Valve Implantation

[0045] One method of introducing the temporary check valve 100 into the ventricular cavity is through a puncture opening 172 in the ventricle 178 near the apex 176 of the heart 174 as depicted in FIG. 1 1. The temporary check valve 100 is held collapsed to pass through the puncture by the introducer sheath 164. Collapse of the check valve 100 minimizes the diameter of the seal ring 122 and brings the frame structure 106 and sleeves against the exterior surface of the tool shaft 160 and the interior surface of the introducer sheath 164. When the check valve 100 is collapsed against the body of the tool shaft 160, the sleeve strips 1 10 are appropriately wrinkled up and folded.

[0046] The collapsed temporary check valve 100 may be positioned at the end of the tool shaft 160 within the introducer sheath 164 for insertion or, alternatively, the tool shaft 160 may be initially inserted and the temporary check valve 100 may be placed about the outer diameter of the tool shaft 160 and slid along the tool shaft 160 within the introducer sheath 164 until it is in an appropriate location for deployment. A pull wire or rod or additional concentric shaft may be connected to the proximal edge of the frame

structure 106 to control and slide the temporary check valve 100 along the length of the tool shaft 160. When the seal ring 122 is correctly positioned, the introducer sheath 164 is moved proximally, away from the seal ring 122. Movement of the introducer sheath 164 (and body temperature where the frame is constructed of a shape memory alloy) allows expansion of the seal ring 122 and distal portion of the frame structure 106.

[0047] The temporary check valve 100 is usually positioned just below the existing valve inside the heart 174. In one embodiment, the seal ring 122 expands until it seals against the walls of the ventricular chamber, or the inner or under-surface of an existing prosthetic valve. If the seal ring 122 of the temporary check valve 100 is made of an elastically-expanding, toroidal balloon, its collapsed inner diameter may be similar to that of the introducer sheath 164. Alternatively, where the seal is made from a less-elastic, non-inflatable material, then the seal structure may be folded up and wrinkled as the check valve 100 is collapsed and inserted into the introducer sheath 164. If the seal is made from helically wound up material such as thin metal, it may be unwound in position expanding its diameter to the desired dimension.

[0048] In normal function, the sleeve 108 is opened or closed by action of the blood flow and pressure within the ventricle 178 or other space behind the check valve 100. In embodiments where the sleeve 108 comprises a plurality of sleeve strips 1 10, the sleeve strips 1 10, other than a funnel strip 1 18 in the funnel section 104, are either all open or all closed. The funnel strip 1 18 is fixed to the frame structure 106 at both its distal and proximal edges, such that its proximal edge does not flap during the open configuration. During systole, the ventricle 178 contracts and forces blood toward the valve (e.g., aortic valve 182) being replaced or repaired and through the temporary check valve 100. The unsecured edges of the sleeve strips 1 10 move inward away from the interior surface of the frame structure 106 as the blood flows through the collapsible mesh of the frame structure 106. The blood continues past the flapping sleeve strips 1 10 into the interior 120 of the frame structure 106.

[0049] During diastole, the sleeve strips 1 10 are forced outward against the collapsible mesh of the inner surface of the frame structure 106 and their proximal unsecured edges make contact with the distal edge of each adjacent sleeve strip 1 10 to create a seal, thus preventing backflow of blood into the ventricle 178 (or other vessel or anatomic area in which the temporary check valve 100 may be positioned). FIG. 2B is a cross-sectional schematic view showing how blood passes through the temporary check valve 100 when the sleeve strips 1 10 are open (i.e., flapping). The arrows show the direction of blood flow. FIGS. 1 A and 1 B depict the check valve 100 in the closed position with the sleeve strips 1 10 pressed against the collapsible mesh of the frame structure 106 to prevent backflow.

[0050] Once the temporary check valve 100 is in place, additional tools can be passed through the central lumen of the tool shaft 160 over which the temporary check valve 100 is positioned, to perform the necessary procedures on the native valve or prosthetic valve without compromising the cardiac output function of the heart 174 or interfering with the normal filling of the coronary arteries. Provisions may be made so that any tool inserted through the lumen 162 of the tool shaft 160 as well as the hollow tool shaft 160 itself is appropriately sealed to prevent blood from leaking out of the heart 174 through the hollow tool shaft 160.

[0051] In a second implementation, the hollow tool shaft 160 on which the temporary check valve 100 is mounted and the introducer sheath 164 may comprise a catheter that is passed through the aorta 180 from downstream of the native valve, through the native valve, and positioned upstream of the native valve as opposed to being delivered and positioned through the apex 176 of the heart 174.

[0052] In accordance with a third implementation, the annular seal ring 122 may be fabricated from a solid structure, for example, an elastic hoop of wire that is self expanding once it is positioned on the interior of a ventricle chamber or vessel wall. In one

embodiment, the wire hoop may be formed of the same shape memory material as the frame structure 106, e.g., Nitinol. The solid structure may have sufficient elasticity to push against the inner surface of the wall and make the necessary seal. The solid structure may also contain an appropriately compliant covering material to properly deform and make contact with the wall of the ventricle chamber or vessel within which it is inserted. A helically wound configuration, unwound to expand and push against the inner surface of the wall can also be used as previously described.

[0053] All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto may vary. [0054] The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments of the invention as defined in the claims. Although various embodiments of the claimed invention have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of the claimed invention. Other embodiments are therefore contemplated. It is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative only of particular embodiments and not limiting. Changes in detail or structure may be made without departing from the basic elements of the invention as defined in the following claims.

Claims

CLAIMS What is claimed is

1 . A temporary vascular check valve comprising

a cylindrical mesh frame structure defining an interior space and configured to radially expand and contract;

an annular expandable seal structure positioned at a distal end of the frame structure; and

a sleeve comprising a plurality of annular sleeve strips lining the interior of the frame structure, wherein distal edges of the sleeve strips are attached to the frame structure and proximal edges of the sleeve strips are not attached to the frame structure.

2. The temporary vascular check valve of claim 1 , wherein the frame structure is made of a shape memory alloy.

3. The temporary vascular check valve of claim 1 , wherein the sleeve strips are made of pericardium.

4. The temporary vascular check valve of claim 1 , wherein the proximal edges of each of the sleeve strips overlap respective distal edges of adjacent sleeve strips.

5. The temporary vascular check valve of claim 1 further comprising a frustum-shaped mesh frame structure section integral with and extending proximally from the cylindrical mesh frame structure.

6. The temporary vascular check valve of claim 5, further comprising a funnel-shaped strip positioned in the frustum-shaped section of the frame structure at a proximal end of the frame structure, wherein both a proximal edge and a distal edge of the funnel strip are secured to the frame structure.

7. The temporary vascular check valve of claim 6, wherein the proximal edge of a most proximal sleeve strip overlaps the distal edge of the funnel strip.

8. The temporary vascular check valve of claim 6 further comprising a cylindrical mesh collar section extending proximally from a smaller diameter portion of the frustum- shaped section of the frame structure.

9. The temporary vascular check valve of claim 8 further comprising a collar that retains the cylindrical mesh collar section at a constant diameter.

10. A method of inserting a temporary check valve in a vascular structure comprising

inserting an introducer sheath within a vascular structure;

placing a radially expandable temporary check valve in a radially compressed state about a tubular shaft, wherein the temporary check valve comprises an expandable annular seal structure;

inserting the tubular shaft and the check valve within the introducer sheath;

advancing the temporary check valve along the tubular shaft to a desired position within the vascular structure;

proximally retracting the introducer sheath from around the temporary check valve to allow the temporary check valve to radially expand within the vascular structure; and

expanding the expandable seal structure to seal against sidewalls of the vascular structure.

1 1 . The method of claim 10 further comprising raising a temperature of the frame structure above room temperature to initiate radial expansion of the temporary check valve.

12. The method of claim 10 further comprising positioning the expandable annular seal structure against an underside of an existing in vivo, in situ bioprosthetic valve.