A delivery device for percutaneously deploying a stented prosthetic heart valve, including a delivery sheath, an inner shaft, and a spindle. The inner shaft is slidably disposed within a lumen of the delivery sheath. The spindle is attached to the shaft and includes a hub defining at least one longitudinal slot sized to slidably receive a post of the stented valve. An outer surface of the hub forms a curved proximal segment. The device provides a loaded state in which the delivery sheath retains the stented valve over the inner shaft and coupled to the spindle via the slot. In a deployed state, the distal end of the delivery sheath is withdrawn from the prosthesis to permit the stented valve to release from the slot, sliding along the curved outer surface of the hub.