A prosthetic heart valve according to the present disclosure comprises a radially collapsible and expandable annular frame and a leaflet structure comprising a plurality of leaflets mounted within the frame. The frame in particular embodiments can have commissure attachment portions that are configured to support the commissures of the leaflets at locations spaced radially inwardly toward the longitudinal flow axis of the prosthetic valve relative to the frame portions circumscribing the moveable portions of the leaflets. When the leaflets open under pressure of blood flowing through the prosthetic valve, the moveable portions of the leaflets are retained at positions spaced inwardly from the inner surface of the frame to protect against abrasion of the leaflets.