Doppler echocardiography data
All Doppler echocardiography exams were performed with a Vivid S5 (GE®
Vingmed Ultrasound, Israel) and a Vivid T8 (GE® Medical Systems, China)
ultrasound system. Echocardiographic data was collected and analysed
according to the American Society of Echocardiography and European
Association for Cardiovascular Imaging guidelines by 5 experienced
certified cardiologists (cardiac imaging specialists, Level III).
Anonymous electronic recordings were analysed according to current
echocardiographic recommendations. 12–14
Aortic valve phenotype was assessed in the parasternal short-axis view.
BAV was classified according to Schaefer et al as: I, fusion of coronary
leaflets, II, fusion of right coronary and non-coronary leaflets and
III: fusion of non-coronary and left coronary
leaflets.15
Left ventricular outflow tract (LVOT) diameter was measured at the
insertion of the leaflets in a zoom of the parasternal long-axis view
and used to calculate the LVOT area. Stroke volume was obtained by
multiplying the LVOT area by the velocity time integral measured by
pulsed wave Doppler in the LVOT. Stroke volumen was indexed to BSA to
obtain stroke volume index. The transvalvular flow rate was calculated
by dividing the stroke volume by the left ventricular ejection time.
LVEF was calculated with Simpson’s biplane method.
AS haemodynamic severity was assessed with the following parameters:
dimensionless index (ratio of the VTI of the LVOT flow on the VTI of the
aortic valve flow), mean gradient (modified Bernoulli equation), maximum
Doppler velocity (Vmax, with continuous wave Doppler) and aortic valve
area (AVA, calculated with continuity equation). AS severity was
categorised based on fulfilment of at least 2 criteria. into mild AS
(AVA >1.5cm2, Vmax <3.0m/s,
mean gradient <20mmHg), moderate AS (AVA
1-1.5cm2, Vmax 3.0-3.9m/s, mean gradient 20-39mmHg)
and severe AS (AVA <1cm2, Vmax ≥4.0m/s, mean
gradient ≥40mmHg, dimensionless index ≤ 0,25).14
All patients underwent baseline TTE and follow-up imaging studies
according medical advise. Outcomes including aortic valve replacement
(AVR), transcatheter aortic valve replacement (TAVR) all-cause mortality
and cardiovascular mortality were collected until 20 March 2020.
AVR was defined as the need for mechanical (surgical or transcatheter
replacement) treatment due to severe symptomatic AVS according current
guidelines, including an estimated aortic valve area <0.9
cm2. The standard of practice at our institution is to
intervene on severe AS primarily on the basis of cardiovascular symptoms
or ventricular dysfunction, based on current recommendations. In
asymptomatic patients, referral for surgery was made according to
international guidelines: dilated aortic sinus or ascending aorta
>50 mm in BAV or left ventricle ejection fraction
<50%. 14
All procedures followed the principles of the Declaration of Helsinki
and good clinical practice regulations.