- Subaortic membrane
- Subaortic membrane (denoted by arrow) noted beneath the aortic valve causing subaortic narrowing
- Subaortic membrane
- Subaortic membrane (denoted by the arrow) beneath the aortic valve causing subaortic narrowing
- Flow turbulence in the subaortic region consistent with subaortic stenosis
- Mild aortic regurgitation
Subaortic membrane
- Color aliasing begins at the level of the circumferential fibromuscular ridge
- Mild valvar aortic regurgitation
- Interventricuar septal hypertrophy
- Subaortic membrane
- Continuous wave Doppler across the subaortic region
- Spectral Doppler velocity consistent with severe subaaortic stenosis
Aortic Stenosis Severity
| Aortic Stenosis | Mild | Moderate | Severe |
| Peak velocity (meters/sec) | 2.6-3.0 | 3-4 | >4 |
| Mean Gradient | <20 (<30**) | 20-40*(30-50**) | >40*(>50**) |
| Aortic Valve Area (cm2) | >1.5 | 1.0-1.5 | <1.0 |
| Indexed Aortic Valve Area (cm2/m2) | >0.85 | 0.6-0.85 | <0.6 |
| Velocity Ratio | >0.5 | 0.25-0.50 | <0.25 |
*AHA/ACC guidelines
**ESC Guidelines
Source: Kyle, American Society of Echocardiography (ASE)
From the apical 5 chamber view, the severity of subaortic stenosis is best assessed utilizing pulse and continuous-wave Doppler to measure the peak instantaneous and mean pressure gradients across the subaortic region. This is also a good view to assess for aortic regurgitation.