From the Guidelines
The maximum normal flow velocity across the aortic valve in adults is less than 2 m/s, as indicated by the 2014 AHA/ACC guideline for the management of patients with valvular heart disease 1. This value is based on the definition of valvular aortic stenosis (AS) stages, where aortic V max <2 m/s is considered at risk of AS, and values between 2.0–2.9 m/s indicate mild AS. Key factors influencing this measurement include:
- Valve anatomy, such as bicuspid aortic valve or aortic valve sclerosis
- Valve hemodynamics, including aortic V max and mean ΔP
- Consequences, such as early LV diastolic dysfunction
- Symptoms, which are typically absent in early stages of AS The guideline provides a comprehensive framework for managing patients with valvular heart disease, emphasizing the importance of accurate diagnosis and staging to guide treatment decisions. In clinical practice, Doppler echocardiography is commonly used to measure blood flow velocities through the heart chambers and valves, including the aortic valve. By assessing aortic V max, clinicians can identify patients with abnormal flow velocities, potentially indicating aortic valve stenosis or other pathology, and initiate appropriate management to improve outcomes.
From the Research
Maximum Normal Flow Velocity Across the Aortic Valve
- The maximum normal flow velocity across the aortic valve in adults can be estimated from various studies, with one study reporting a value of 1.28 +/- 0.18 m/s in the ascending aorta from the suprasternal position 2.
- Another study measured blood velocity distribution in the human ascending aorta and found a skewed peak systolic velocity profile with the highest velocity along the left posterior wall, but did not provide a specific maximum normal flow velocity value 3.
- A study on the determination of normal values of the aortic blood flow profile using continuous Doppler echocardiography reported maximum flow velocities of 1.28 +/- 0.18 m/s in the ascending aorta from the suprasternal position and 1.17 +/- 0.22 m/s in the descending aorta 2.
- However, it is essential to note that the maximum normal flow velocity may vary depending on the location and method of measurement.
Comparison of Studies
- The study by 2 provides a direct measurement of the maximum normal flow velocity across the aortic valve, while the study by 3 focuses on the blood velocity distribution in the ascending aorta.
- The study by 4 estimates pressure gradients across the aortic valve using velocity-encoded cine MR imaging, but does not provide a direct measurement of the maximum normal flow velocity.
- The studies by 5 and 6 discuss the relationship between aortic valve area and mean aortic valve gradient, as well as the role of echocardiography in assessing aortic stenosis, but do not provide information on the maximum normal flow velocity across the aortic valve.
Key Findings
- The maximum normal flow velocity across the aortic valve in adults is approximately 1.28 +/- 0.18 m/s in the ascending aorta from the suprasternal position 2.
- The maximum normal flow velocity may vary depending on the location and method of measurement.
- Further research is needed to determine the maximum normal flow velocity across the aortic valve in different populations and under various conditions.