Table 22. Step 1: Diagnosis of severe aortic stenosis^74–87.

	Characteristics of severe aortic stenosis
Physical examination	Pulsus parvus et tardus Ejective systolic murmur with telesystolic peak Hypophonetic second heart sound Hypophonetic first heart sound Gallavardin phenomenon Paradoxical double second heart sound or single second heart sound
Electrocardiogram	Left chamber overload Altered ventricular repolarization (strain pattern)
Chest radiography	Cardiothoracic index may be normal Signs of pulmonary congestion
Echocardiogram	AVA ≤ 1.0 cm2 Indexed AVA ≤ 0.6 cm2/m2 Mean transaortic gradient ≥ 40 mmHg Maximum aortic jet velocity ≥ 4.0 m/s Flow rate ratio between LV outflow tract and aortic valve < 0.25
Dobutamine stress echocardiogram	Indicated for evaluation of anatomical severity in patients with low-flow, low-gradient AS, with low LVEF, defined as AVA ≤ 1.0 cm2, LVEF < 50% and mean transaortic gradient < 40 mmHg* In the presence of contractile reserve (increase of ≥ 20% in stroke volume and/or increase of > 10 mmHg in mean transaortic gradient), patients with reduction or preservation in peak AVA during stress have severe AS (increase of up to 0.2 cm2 in AVA is accepted as a criterion of preserved AVA). Patients with increasing in AVA ≥ 0.3 cm² are defined as moderate AS (pseudo-severe AS) In the absence of contractile reserve, it is necessary to corroborate anatomical severity with the aortic calcium score
Multidetector chest computed tomography	Aortic valve calcium score above 1,300 AU for women and 2,000 AU for men confirms severe AS
Hemodynamic study	Transaortic gradient (peak) ≥ 50 mmHg
Special situation	Low-flow, low-gradient AS with preserved LVEF (“paradoxical”), defined as: AVA ≤ 1.0 cm2, LVEF > 50%, and transaortic mean gradient < 40 mmHg*. In these cases, we must evaluate the following parameters for defining severe AS: –Indexed AVA ≤ 0.6 cm2/m2 –High aortic valve calcium score –Systolic arterial pressure ≤ 140 mmHg –Indexed stroke volume < 35 mL/m2 Patients with all of the above parameters, but normal indexed stroke volume (> 35 ml/m²) are defined as having normal-flow, low-gradient AS. This entity has been recently described; evidence is scarce, and these patients appear to benefit from valve intervention when they are symptomatic88,89

^*In cases of low-flow, low-gradient AS with preserved or low LVEF, we must pay attention to possible errors in echocardiographic measurement. AS: aortic stenosis; AVA: aortic valve area; LV: left ventricle; LVEF: left ventricular ejection fraction.