A prosthesis configured to grasp intralumenal tissue when deployed within a body cavity, the prosthesis comprising: an expandable frame comprising a proximal end and a distal end and a longitudinal axis extending therethrough, the frame configured to collapse radially for delivery and to expand radially upon deployment, wherein when the frame is in an expanded configuration, the frame has a larger cross-sectional dimension in a middle portion of the frame and a smaller cross-sectional dimension in a proximal portion and a distal portion of the frame, wherein the middle portion is between the proximal and distal portions; a plurality of proximal anchors extending from the frame and expandable from a collapsed configuration to an expanded configuration, wherein in the expanded configuration, each proximal anchor extends proximally away from the proximal end of the frame and then turns to extend distally, each proximal anchor extending to an end positioned radially outward from the frame; and a plurality of distal anchors extending from the frame and expandable from a collapsed configuration to an expanded configuration, wherein in the expanded configuration, each distal anchor extends distally away from the distal end of the frame and then turns to extend proximally, each distal anchor extending to an end positioned radially outward from the frame; wherein in the expanded configuration, the ends of each of the plurality of proximal anchors are substantially perpendicular to the longitudinal axis of the frame; wherein in the expanded configuration, each of the plurality of distal anchors is bent near a base of the distal anchor to extend radially outwardly away from the frame along a first segment and is then bent to point generally proximally along a second segment ending in a tip. an expandable frame comprising a proximal end and a distal end and a longitudinal axis extending therethrough, the frame configured to collapse radially for delivery and to expand radially upon deployment, wherein when the frame is in an expanded configuration, the frame has a larger cross-sectional dimension in a middle portion of the frame and a smaller cross-sectional dimension in a proximal portion and a distal portion of the frame, wherein the middle portion is between the proximal and distal portions; a plurality of proximal anchors extending from the frame and expandable from a collapsed configuration to an expanded configuration, wherein in the expanded configuration, each proximal anchor extends proximally away from the proximal end of the frame and then turns to extend distally, each proximal anchor extending to an end positioned radially outward from the frame; and a plurality of distal anchors extending from the frame and expandable from a collapsed configuration to an expanded configuration, wherein in the expanded configuration, each distal anchor extends distally away from the distal end of the frame and then turns to extend proximally, each distal anchor extending to an end positioned radially outward from the frame; wherein in the expanded configuration, the ends of each of the plurality of proximal anchors are substantially perpendicular to the longitudinal axis of the frame; wherein in the expanded configuration, each of the plurality of distal anchors is bent near a base of the distal anchor to extend radially outwardly away from the frame along a first segment and is then bent to point generally proximally along a second segment ending in a tip.