Table 1

Main characteristics of the two randomised controlled trials

	AVATAR	RECOVERY
Trial design	Multinational, randomised, controlled, parallel-group, event-driven	Multicentre, randomised, controlled, parallel-group, open-label
Recruitment sites	Nine medical centres, seven European Union countries	Four medical centres, one country
Recruitment period	June 2015–September 2020	July 2010–April 2015
Follow-up period (median)	32 months	73 months
Inclusion criteria	Asymptomatic patients. Severe AS (AVA <1 cm², Vmax >4 m/s or MG >40 mm Hg). Negative exercise tolerance test.	Asymptomatic patients. Very severe AS (AVA <0.75 cm², Vmax >4.5 m/s or MG >50 mm Hg). Exercise testing was selectively performed to evaluate patients with non-specific symptoms (24 patients) and those with a positive exercise test were excluded (3 patients).
Main exclusion criteria	Symptoms (exertional dyspnoea, syncope, presyncope or angina). LVEF <50%. Very severe AS (>5.5 m/s at rest). Clinically significant aortic regurgitation or mitral valve disease. Significant aortic root and/or ascending aorta dilatation requiring surgery. Previous cardiac surgery.	Symptoms (exertional dyspnoea, syncope, presyncope or angina). LVEF <50%. Clinically significant aortic regurgitation or mitral valve disease. Previous cardiac surgery.
Aetiology of aortic stenosis	Degenerative valvular disease: 133 patients (84.7%). Bicuspid aortic valve: 22 patients (14.0%). Rheumatic valvular disease: 2 patients (1.3%).	Degenerative valvular disease: 48 (33%). Bicuspid aortic valve: 88 patients (61%). Rheumatic valvular disease: 9 patients (6%).
Primary endpoints	All-cause mortality or major adverse cardiovascular events comprised all-cause death, acute myocardial infarction, stroke and unplanned heart failure hospitalisation needing intravenous treatment with diuretics or inotropes.	Operative mortality (death during or within 30 days after surgery) or death from cardiovascular causes during the entire follow-up period.

Data are presented as available by the relevant published studies.
AS, aortic stenosis; AVA, aortic valve area; AVATAR, Aortic Valve Replacement versus Conservative Treatment in Asymptomatic Severe Aortic Stenosis; LVEF, left ventricular ejection fraction; MG, mean gradient; RECOVERY, Randomized Comparison of Early Surgery versus Conventional Treatment in Very Severe Aortic Stenosis; Vmax, maximal velocity across the aortic valve.