From the Guidelines
Aortic stenosis is primarily assessed through echocardiography, which provides key measurements to determine severity, including peak aortic jet velocity, mean pressure gradient across the aortic valve, and aortic valve area, as recommended by the 2021 ACC/AHA guideline for the management of patients with valvular heart disease 1.
Key Measurements for Aortic Stenosis Severity
The most important measurements for assessing aortic stenosis severity include:
- Peak aortic jet velocity (severe if >4 m/s)
- Mean pressure gradient across the aortic valve (severe if >40 mmHg)
- Aortic valve area (severe if <1.0 cm²)
- The dimensionless index, which is the ratio of the left ventricular outflow tract velocity to aortic jet velocity, is also valuable (severe if <0.25) 1, 2 ### Echocardiography in Aortic Stenosis Assessment Echocardiography is the preferred method for assessing aortic stenosis severity, as it provides a comprehensive evaluation of valve anatomy and function, as well as left ventricular size and function 3, 1.
Additional Diagnostic Tools
Other diagnostic tools, such as cardiac catheterization, dobutamine stress echocardiography, and CT scanning, may be used in specific cases, such as when echocardiographic findings are inconclusive or discordant with clinical presentation 1, 4, 2.
Clinical Decision-Making
These measurements are crucial because they guide treatment decisions, including timing of intervention, which is typically recommended when symptoms develop in severe stenosis or when left ventricular dysfunction occurs even in asymptomatic patients 1.
From the Research
Measurements for Aortic Stenosis
- Aortic stenosis affects 3% of persons older than 65 years, and survival decreases rapidly after symptoms appear 5.
- The disease worsens when compensatory mechanisms, such as left ventricular hypertrophy and atrial augmentation of preload, become inadequate, leading to symptoms of heart failure, angina, or syncope 5.
- Measurements for aortic stenosis include: + Peak instantaneous velocity + Mean gradient + Effective orifice area + LV dimensions and systolic function + Aortic diameter + Mitral valve appearance and function + RV size and function + PA pressure 6
- Trans-thoracic echocardiogram is the main imaging technique used to diagnose aortic stenosis, but other imaging methods, such as ECG-gated computed tomography and cardiac magnetic resonance imaging, can also be used to further clarify the diagnosis 7.
- Serial Doppler echocardiography is recommended every six to 12 months for severe aortic stenosis, every one to two years for moderate disease, and every three to five years for mild disease 5.
- Focused cardiac ultrasound (FoCUS) can be used to screen for aortic stenosis, and visual AS and calcification scores are good objective parameters in screening for AS with FoCUS 8.
Diagnosis and Treatment
- Aortic valve replacement is recommended for most symptomatic patients with evidence of significant aortic stenosis on echocardiography 5.
- Surgical valve replacement is the standard of care for patients at low to moderate surgical risk, while transcatheter aortic valve replacement may be considered in patients at high or prohibitive surgical risk 5.
- Electronic provider notifications (EPN) can increase rates of aortic valve replacement for severe aortic stenosis, lessen gender and age disparities in AVR utilization, and improve survival time 9.