Aortic Stenosis (AS) is the commonest valve disease requiring surgery but the risks and benefits of a strategy of early AVR versus expectant management In asymptomatic patients are unclear. The Early valve replacement in severe ASYmptomatic AS (EASY-AS) study will test the hypothesis that early AVR results in reduced incidence of the primary outcome, a composite of cardiovascular death and heart failure hospitalisation when compared to a guideline recommended startegy of expectant management.