Selection of patients Due to the existence of the tried and tested surgical valve replacement with good long-term results the selection of patients for percutaneous aortic valve implantation (PAVI), which should be done with multidisciplinary consultation between cardiologists, surgeons, imaging specialists and anaesthesiologists, involves several critical steps [5]. Candidates considered for PAVI must have severe symptomatic aortic stenosis in addition to a formal contraindication to surgery or other characteristics that would limit their surgical candidacy because of excessive mortality or morbidity risk (Figure 1). The procedure should be offered to patients who have a potential for functional improvement after valve replacement. It is not recommended for patients who simply refuse surgery on the basis of personal preference. Confirming the severity of aortic stenosis Currently, PAVI is only indicated in patients with calcified pure or predominant symptomatic aortic stenosis. The different imaging modalities can assist in the selection process by providing important information on the aortic valve, coronary arteries, and vascular structures. First, the severity of aortic Percutaneous aortic valve implantation stenosis should be assessed. Both transthoracic (TTE) and transoesophageal (TEE) Doppler echo- cardiography are the preferred tools to assess the severity of aortic stenosis. In addition, the exact anatomy of the aortic valve should be assessed. Echocardiography, multi-slice CT (MSCT) and magnetic resonance imaging (MRI) can all help to distinguish between a bicuspid and a tricuspid aortic valve. It is important to point out that implantation of available percutaneous prostheses is contraindicated in the case of a unicuspid or bicuspid aortic valve, because of the risk of incomplete deployment, significant paravalvular regurgitation, and displacement of the prosthesis [5, 6]. A severely calcified aortic valve may result in the inability to cross the native valve with the catheter. Bulky leaflets and calcifications on the free edge of the leaflets may increase the risk of occlusion of the coronary ostia during aortic valve implantation. Therefore, the extent and exact location of calcifications should be carefully assessed before the implantation procedure. The assessment of coronary anatomy is also important in the selection process. Conventional coronary angiography should be performed to exclude the presence of significant coronary artery disease. Conventional angiography remains the “gold standard”. Severe aortic stenosis: AVA < 1 cm2, mean gradient > 40 mmHg Clinical symptoms Indication for aortic valve replacement Assessment of patient risk according to clinical evaluation and using risk scores (e.g. EuroSCORE, STS score) in a multidisciplinary round No contraindication for surgery Contraindication for surgery PAVI not eligible Evaluation for PAVI Transfemoral approach not eligible Transapical approach Subclavian approach Surgical aortic valve replacement Accepting the high risk Accepting the poor outcome Medically treatment or baloon aortic valvuloplasty Arch Med Sci 3, June / 2010 Figure 1. Algorithm to determine the treatment options of patients with severe aortic valve stenosis AVA – aortic valve area, PAVI – percutaneous aortic valve implantation PAVI 297