A prosthetic aortic valve intended for native or valve-in-valve within bioprostheses includes an expandable support scaffold and valve leaflets disposed within an upper leaflet portion of the support scaffold. The valve leaflets within the upper portion may be located within the annulus (intravalvular), above the annulus, or above the native or prosthetic leaflets (supravalvular). The valve within a previously implanted degenerated heart valve such that a base or lower portion of the replacement valve is within the previously implanted valve and the upper portion is expanded within the aorta, the internal area of the valve can be increased and the hemodynamics of the valve improved. Alternatively, the valve may include separate upper and lower portions allowing the portions to be implanted sequentially and the length and other characteristics of the valve to be adjusted based on patient anatomy and condition.