Objective:To explore the feasibility and safety of transcatheter aortic valve prosthesis replacement in a sheep model. Methods:Under the guidance of fluoroscopy and echocardiography,the self-expanding nitinol stents integrated with porcine pericardial valves were transcatheterly implanted at the native position of eight sheep through the common carotid artery using 18F delivery systems. Immediately after the procedure,the aortic-root angiogram,left ventriculargraphy and echocardiography were carried out to evaluate the function of the prosthetic valve and its influence on coronary flow or mitral valve. Results:Six animals were successfully implanted with the prosthesis without obstruction of the coronary artery orifice. The procedure failed in two sheep as a result of malposition. Lethal heart failture occurred in one sheep due to too inferior positioning of the prosthesis,and the other died of acute myocardial infarction related life-threatening ventricular arrhythmia with too superior positioning of the prosthesis. Conclusion:The aortic valve prosthesis consisted of self-expanding nitinol stent and porcine pericardial valve,and could be successfully implanted using a retrograde approach via the common carotid artery with gratifying immediate outcomes.