From the Guidelines
Aortic regurgitation (AR) is graded using color Doppler in the parasternal long-axis (PLAX) view based on the width of the regurgitant jet relative to the left ventricular outflow tract (LVOT) width, with mild AR characterized by a jet width less than 25% of the LVOT width, moderate AR showing a jet width between 25% and 64% of the LVOT width, and severe AR indicated when the jet width is 65% or greater of the LVOT width, as recommended by the European Association of Cardiovascular Imaging 1.
The assessment of AR severity using color Doppler is a semi-quantitative method that provides valuable information about the regurgitant volume. The width of the regurgitant jet is measured in diastole immediately below the aortic valve, at the junction of the LV outflow tract and aortic annulus, in the parasternal long-axis view. The color Doppler settings should be optimized with appropriate Nyquist limits (50-60 cm/s) to avoid overestimation or underestimation of the jet width.
The grading of AR severity can be further refined using other parameters such as:
- Vena contracta width, with a width of <3 mm indicating mild AR and a width of >6 mm indicating severe AR 1
- Pressure half-time, with a shorter half-time indicating more severe AR 1
- Regurgitant volume, with a volume of <30 mL indicating mild AR and a volume of ≥60 mL indicating severe AR 1
It is essential to integrate these parameters for a comprehensive assessment of AR severity, as the width of the regurgitant jet alone may not accurately reflect the severity of the regurgitation. The European Association of Cardiovascular Imaging recommends using a combination of these parameters to grade AR severity, with severe AR indicated by a jet width ratio of ≥65% or a vena contracta width of ≥6 mm 1.
In clinical practice, the assessment of AR severity using color Doppler and other parameters should be performed in accordance with the guidelines and recommendations of the European Association of Cardiovascular Imaging and the American Society of Echocardiography, to ensure accurate diagnosis and appropriate management of patients with AR.
From the Research
Grading Aortic Regurgitation using Color Doppler
To grade aortic regurgitation based on color Doppler in parasternal long-axis transthoracic echocardiogram according to American Society of Echocardiography guidelines, several parameters can be considered:
- The ratio of maximal jet height (JH) to left ventricular outflow tract (LVOT) height can be used to grade AR on a scale of 0-4 2.
- The JH/LVOH ratio can also be used to predict mild aortic regurgitation with 96% accuracy when the ratio is ≤ 25%, and severe aortic regurgitation with 96% accuracy when the ratio is ≥ 40% 3.
- Absolute JH at the origin of the regurgitant jet can be used as a simple and practical method for assessing the degree of aortic regurgitation, with a correlation coefficient of 0.89 with angiography 3.
Parameters for Grading Aortic Regurgitation
The following parameters can be used to grade aortic regurgitation:
- Ratio of maximal jet height to LVOT height
- JH/LVOH ratio
- Absolute JH at the origin of the regurgitant jet
- Regurgitant fraction (RF) can also be estimated, with proposed grading scales:
Clinical Application
The American Society of Echocardiography recommends an integrative algorithm for grading native aortic regurgitation, which includes the use of color Doppler parameters such as the ratio of maximal jet height to LVOT height and the JH/LVOH ratio 5. However, the feasibility and accuracy of these parameters may vary, and a consolidated assessment of clinical and multimodality findings should be used to guide surgical intervention in symptomatic patients with discordant or inconclusive echocardiographic grading 5.