In recent years, there has been a revival in the use of bioprosthetic valves as aortic substitutes. For example, during 2008 in Germany, among 12,397 patients who underwent isolated aortic valve procedures, 78% received a biological prosthesis and 21% a mechanical valve, while only 1% underwent valve repair. However, whilst this situation is the reverse of that during the 1990s, the question must be asked as to whether this is simply a fluctuating fashion, or a reflection of other factors.