Aortic Stenosis Severity
Interpret AS severity and phenotype from echo data. Identify concordant severe AS, discordant patterns, and low-flow low-gradient subtypes.
Echo measurements
Enter available values — partial input is supported.
Primary parameters
Severe ≥ 4.0 m/s
Severe ≥ 40 mmHg
Severe < 1.0 cm²
Additional parameters
< 50% = reduced EF
< 35 mL/m² = low flow
Severe < 0.25
Measurement context
Valve calcification
Doppler acquisition quality
Assessment
Enter at least one velocity, gradient, or AVA measurement to see the assessment.
Why one number is not enough
AVA and gradient can disagree
AVA is flow-dependent. In low-flow states, gradient falls even when the valve is severely stenosed. Neither parameter alone is sufficient — concordance is what matters.
Low flow changes everything
Low stroke volume reduces gradient independently of valve severity. SVI < 35 mL/m² signals that the gradient may be underestimating the true stenosis.
High flow inflates gradient
Anemia, aortic regurgitation, or high cardiac output states can push velocity and gradient above thresholds even with a non-severely stenosed valve. Always consider flow context.
Learn the echo reasoning pathway
Review how valve severity, LV function, filling pressures, and intraoperative TEE findings connect in perioperative echo assessment.