Recommendations D. Recommendations on indications for intervention^a in symptomatic (A) and asymptomatic (B) aortic stenosis and recommended mode of intervention (C).

A) Symptomatic aortic stenosis	Classb	Levelc
Intervention is recommended in symptomatic patients with severe, high-gradient aortic stenosis [mean gradient ≥40 mmHg, peak velocity ≥4.0 m/s, and valve area ≤1.0 cm2 (or ≤0.6 cm2/m2)] . 235,236	I	B
Intervention is recommended in symptomatic patients with severe low-flow (SVi ≤35 mL/m2), low-gradient (<40 mmHg) aortic stenosis with reduced ejection fraction (<50%), and evidence of flow (contractile) reserve. 32,237	I	B
Intervention should be considered in symptomatic patients with low-flow, low-gradient (<40 mmHg) aortic stenosis with normal ejection fraction after careful confirmation that the aortic stenosis is severed (Figure 3).	IIa	C
Intervention should be considered in symptomatic patients with low-flow, low-gradient severe aortic stenosis and reduced ejection fraction without flow (contractile) reserve, particularly when CCT calcium scoring confirms severe aortic stenosis.	IIa	C
Intervention is not recommended in patients with severe comorbidities when the intervention is unlikely to improve quality of life or prolong survival >1 year.	III	C
B) Asymptomatic patients with severe aortic stenosis
Intervention is recommended in asymptomatic patients with severe aortic stenosis and systolic LV dysfunction (LVEF <50%) without another cause. 9,238,239	I	B
Intervention is recommended in asymptomatic patients with severe aortic stenosis and demonstrable symptoms on exercise testing.	I	C
Intervention should be considered in asymptomatic patients with severe aortic stenosis and systolic LV dysfunction (LVEF <55%) without another cause. 9,240,241	IIa	B
Intervention should be considered in asymptomatic patients with severe aortic stenosis and a sustained fall in BP (>20 mmHg) during exercise testing.	IIa	C
Intervention should be considered in asymptomatic patients with LVEF >55% and a normal exercise test if the procedural risk is low and one of the following parameters is present: • Very severe aortic stenosis (mean gradient ≥60 mmHg or Vmax >5 m/s). 9,242 • Severe valve calcification (ideally assessed by CCT) and Vmax progression ≥0.3 m/s/year. 164,189,243 • Markedly elevated BNP levels (>3- age- and sex-corrected normal range) confirmed by repeated measurements and without other explanation. 163,171	IIa	B
C) Mode of intervention
Aortic valve interventions must be performed in Heart Valve Centres that declare their local expertise and outcomes data, have active interventional cardiology and cardiac surgical programmes on site, and a structured collaborative Heart Team approach.	I	C
The choice between surgical and transcatheter intervention must be based upon careful evaluation of clinical, anatomical, and procedural factors by the Heart Team, weighing the risks and benefits of each approach for an individual patient. The Heart Team recommendation should be discussed with the patient who can then make an informed treatment choice.	I	C
SAVR is recommended in younger patients who are low risk for surgery (<75 yearse and STSPROM/ EuroSCORE II <4%)e,f, or in patients who are operable and unsuitable for transfemoral TAVI. 244	I	B
TAVI is recommended in older patients (≥75 years), or in those who are high risk (STSPROM/ EuroSCORE IIf >8%) or unsuitable for surgery. 197,198,199,200,201,202,203,204,205,206,245	I	A
SAVR or TAVI are recommended for remaining patients according to individual clinical, anatomical, and procedural characteristics. 202,203,204,205,207,209,210,212 f,g	I	B
Non-transfemoral TAVI may be considered in patients who are inoperable and unsuitable for transfemoral TAVI.	IIb	C
Balloon aortic valvotomy may be considered as a bridge to SAVR or TAVI in haemodynamically unstable patients and (if feasible) in those with severe aortic stenosis who require urgent highrisk NCS (Figure 11).	IIb	C
D) Concomitant aortic valve surgery at the time of other cardiac/ascending aorta surgery
SAVR is recommended in patients with severe aortic stenosis undergoing CABG or surgical intervention on the ascending aorta or another valve.	I	C
SAVR should be considered in patients with moderate aortic stenosish undergoing CABG or surgical intervention on the ascending aorta or another valve after Heart Team discussion.	IIa	C
BNP: B-type natriuretic peptide; BP: blood pressure; CABG: coronary artery bypass grafting; CCT: cardiac computed tomography; EuroSCORE: European System for Cardiac Operative Risk Evaluation; LV: left ventricle/left ventricular; LVEF: left ventricular ejection fraction; NCS: non-cardiac surgery; SAVR: surgical aortic valve replacement; STS-PROM: Society of Thoracic Surgeons - predicted risk of mortality; SVi: stroke volume index; TAVI: transcatheter aortic valve implantation; Vmax: peak transvalvular velocity. aSAVR or TAVI. bClass of recommendation. cLevel of evidence. dExplanations other than severe aortic stenosis for a small valve area but low gradient despite preserved LVEF are frequent and must be carefully excluded (Figure 3). eSTS-PROM: http://riskcalc.sts.org/stswebriskcalc/#/calculate, EuroSCORE II: http://www.euroscore.org/calc.html. fIf suitable for surgery (see Table 6). gIf suitable for transfemoral TAVI (see Table 6). hModerate aortic stenosis is defined as a valve area of 1.0-1.5 cm2 (or mean aortic gradient of 25-40 mmHg) in normal flow conditions – clinical assessment is essential to determine whether SAVR is appropriate for an individual patient.