A prosthesis can be deployed within a body cavity. The prosthesis can include an expandable frame, a plurality of proximal prongs, and a plurality of distal prongs. Each prong of the proximal and distal pluralities is connected to the frame. When the frame is expanded, the ends of the prongs are positioned radially outward from the frame. The frame is configured such that radial expansion of the frame causes the ends of the proximal prongs and the ends of the distal prongs to draw closer together.