The RETORIC study is a prospective cohort study with a primary aim to assess the incidence and independent predictors of reduced leaflet motion and valve thrombosis after TAVI procedure using multimodality imaging strategy comprising cardiac CT, transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE). As a secondary aim we will assess the incidence of stroke and transient ischemic attack (TIA) in patients with reduced leaflet motion and/or thrombosis when compared with those with normal leaflet function. In addition we will randomize patients with reduced leaflet motion and/or valve thrombosis to single antiplatelet therapy plus oral anticoagulation therapy versus standard therapy.