What is the velocity cutoff for mild Aortic (Aortic Valve) stenosis?

From the Guidelines

Mild aortic stenosis is defined by a peak aortic jet velocity less than 3.0 m/s, as indicated by the most recent and highest quality study 1. This velocity cutoff corresponds to a valve area greater than 1.5 cm² and a mean pressure gradient less than 20 mmHg in adults with normal cardiac output. The velocity measurement is obtained using continuous-wave Doppler echocardiography, which directly measures the highest velocity of blood flow through the narrowed valve. Key points to consider in the assessment of aortic stenosis severity include:

• The use of multiple acoustic windows for the CW Doppler assessment of AS to avoid misalignment of the beam 1
• The calculation of the mean gradient by averaging the instantaneous gradients over the ejection period 1
• The importance of measuring LVOT diameter and velocity to calculate the valve area by continuity equation 1
• The potential for underestimation of the severity of AS by Doppler echocardiography, particularly in young patients with abnormal aortic valves 1 As aortic stenosis progresses, the velocity increases, with moderate stenosis defined as 3.0-4.0 m/s and severe stenosis as greater than 4.0 m/s, as outlined in the 2015 study 1. Patients with mild aortic stenosis typically remain asymptomatic and generally do not require intervention, though regular monitoring is recommended to assess for disease progression, with yearly evaluations suggested for athletes with mild or moderate AS 1. The assessment of AS severity should combine features of the history, physical examination, and echocardiogram, integrating the various echocardiographic measures of jet velocity, mean gradient, and calculated valve area, as recommended by the 2014 AHA/ACC guideline 1.

From the Research

Definition of Mild Aortic Stenosis

• Mild aortic stenosis is typically defined as a peak aortic jet velocity (Vmax) between 2 and 3 m/s 2, 3
• A study published in the European heart journal. Cardiovascular Imaging in 2023 defined mild to moderate AS as a Vmax between 2 and 4 m/s 4
• Another study published in Echocardiography in 2012 found that a Vmax of 3 m/sec corresponded to a mean pressure gradient (MPG) of 22 mmHg, an aortic valve area (AVA) of 1.15 cm², and an indexed aortic valve area (IAVA) of 0.60 cm²/m² 3

Velocity Cutoff for Mild Aortic Stenosis

• The velocity cutoff for mild aortic stenosis is generally considered to be a Vmax of less than 3 m/s 2, 3
• A study published in the Journal of cardiology in 2011 suggested that a Vmax increase of > 0.4 m/s per year may indicate rapid progression of AS 5
• Another study published in European heart journal. Cardiovascular Imaging in 2020 found that a Vmax of 3.7 m/s corresponded to an AVA of 1 cm² and a ΔP of 32 mmHg, highlighting the potential for inconsistent diagnosis of severe AS using current guidelines 6

Factors Influencing Progression of Aortic Stenosis

• Age, moderate-to-severe AV calcification, and baseline AV Vmax are associated with rapid progression of AS 2
• A study published in European heart journal. Cardiovascular Imaging in 2023 found that AoV Doppler-derived dP/dt and initial AoV calcium score were associated with progression to severe AS 4
• Other factors such as atherosclerosis risk, valve morphology, motion, and hemodynamics may also influence the progression of AS 5