Severe aortic stenosis (AS) is currently defined as an aortic valve area (AVA) <1.0 cm² and/or mean trans-aortic pressure gradient >40 mm Hg and/or peak aortic jet velocity (V_max) >4 m/s. Only patients with severe AS associated with symptoms or left ventricular ejection fraction (LVEF) <50% present an European Society of Cardiology class I indication for aortic valve replacement (AVR),1 based on the findings of Ross's and Braunwald's landmark report showing a dramatic increase in mortality after symptom onset in patients with AS while ‘operative treatment was deemed to be the most common cause of sudden death in asymptomatic AS patients’. The annualised rate of sudden death is estimated to be around 1% per year in asymptomatic patients, which must be weighed up against the operative mortality of AVR (1%–3% in patients aged <70 years and 3%–8% in older patients). In addition, the native valve is usually replaced by a prosthetic valve, which is associated with specific life-threatening complications (thrombosis, endocarditis, need for reoperation). In contrast, it has been suggested that some patients with severe asymptomatic AS may be operated at an excessively advanced stage of the disease, at which myocardial impairment is at least partially irreversible, consequently resulting in a higher risk of mortality and heart failure (HF). This debate remains unresolved, as some experts suggest early surgery to spare the left ventricle (LV) and improve long-term survival, while others advocate AVR only after onset of symptoms.

The slowly progressive nature of AS combined with the relatively advanced age of the population affected by this disease predispose to under-reporting and/or underestimation of symptoms. Thus, a recent series based on cardiopulmonary exercise testing reported a 28% rate of ‘false asymptomatic AS patients’. Exercise …