Calcific aortic valve stenosis is the most common valvular heart disease in developed countries. Without surgery, the prognosis is extremely dismal. Therefore there is general agreement that surgical aortic valve replacement should be offered to patients with symptomatic severe aortic valve stenosis. However, surgery is denied to approx. 30-40% of elderly patients with severe, symptomatic aortic stenosis due to high perioperative risk. Transcatheter aortic valve implantation (TAVI) is a novel and effective procedure which provides a promising treatment option for some of these patients. This review focuses on TAVI systems, the patients who would benefit from TAVI, and the advantages and disadvantages of the procedure.