Yacoub/David techniques for aortic root operation: Success and failures

The aortic valve is a complex structure which functions perfectly in systole and diastole and under a wide range of hemodynamic conditions. Even today, no valve prosthesis can match the function of the native aortic valve. This is - at least partly - due to the fact that the aortic valve is not just an outlet whose cusps do move passively in the blood stream. Rather, the aortic valve - which consists of three cusps attached to the wall of the aortic root - interacts with the aortic root and the left ventricular outflow tract. During the cardiac cycle, the aortic root undergoes complex movements that precede and aide opening and closing of the aortic valve [2, 3, 17, 18]. These complex interactions within the aortic root and throughout the cardiac cycle are not yet completely understood. The aortic valve cusps themselves are thin-walled pocket-like structures, made from specialized tissue with fibrous, elastic, nervous, and muscular properties [13, 16, 21]. No such thin, but at the same time strong and non-thrombogeneic material can be produced in laboratories and even less by industrial processes.