2. To evaluate the influence of the prosthesis to circulating blood the same hemostasis characteristics wiil be evaluated in blood after 20 min of circulation through prosthesis and silicon tube (Platelet count; Platelet aggregation; Prothrombin time, International Normalised Ratio [INR], activated partial thromboplastin time (aPTT), prothrombin Quick, thrombin time, soluble fibrin monomer complexes (SFMC), the measurement of free hemoglobin, P- selectin).