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 TIA in those with reduced leaflet motion and thrombosis when compared with those with normal leaflet function. In addition we will randomise patients with reduced leaflet motion to unchanged standard therapy versus single antiplatelet plus oral anticoagulation therapy. The primary outcome of this nested randomized trial will be the presence of novel ischemic lesions in brain demonstrated by MRI.