We described a new technique (called 'bicuspidization'), which is performed by using autogenous material, without replacement of the aortic valves for the surgical treatment of aortic stenosis and/or insufficiency and tested it in in vitro sheep model. Different stress conditions were simulated by applying three different flow patterns (hemodynamic challenge tests) successively by using a centrifugal pump. It was demonstrated that the competency of the new bicuspid valves was excellent (zero insufficiency). There was a 10-11 mm Hg-increase on trans-valvular gradient comparing the normal hearts. The autogenous bicuspid valve has not blocked the way of the coronary flow in the closed position.