Percutaneous valve implantation is the development of a foldable heart valve that can be mounted on an expandable stent delivered percutaneously through standard catheter-based techniques and implanted within a diseased valve annulus. In cases with severe aortic stenosis, the diseased valve has to be pre-dilated. To perform a true replacement the diseased valve has to be ablated and removed. In this article, we review the development of percutaneous valve replacement technology and discuss future prospects in this field. (C) 2004 by The Society of Thoracic Surgeons.