Transcatheter aortic valve implantation (TAVI) is the replacement of the aortic valve of the heart through the blood vessels. In this minimal invasive surgical procedure, which represents an alternative to standard valve replacement by open heart surgery, a porcine pericardial tissue valve is anchored to a self-expanding nitinol stent. The interaction of blood, stent and aorta are of central importance in determining implants lifetime. CADFEM (Suisse) AG and ADMEDES SCHUESSLER GmbH developed together a numerical modeling procedure for a transcatheter percutaneous aortic valve implantation. The capability to model valve insertion and positioning inside the aorta and interaction with blood flow during a systolic pulse was demonstrated using a state of the art analysis technique provided by ANSYS and FLUENT. This study delivers preliminary information about the evolution of forces, pressures and stresses during a heart pulse and their effects on working conditions, mechanical integrity and lifetime assessment of the implant. Stress - strain curves over a cycle were extracted at the most critical locations in the stent and compared with the fatigue properties of the nitinol stent.