[Severity of aortic stenosis assessed by Doppler techniques]

Area of Science:

• Cardiovascular Imaging
• Echocardiography
• Hemodynamics

Background:

• Aortic stenosis (AS) severity assessment is crucial for patient management.
• Pressure gradient (PG) alone is insufficient for AS severity due to flow dependency.
• Continuous wave (CW) Doppler ultrasound offers a non-invasive method for hemodynamic assessment.

Purpose of the Study:

• To evaluate the efficacy of Doppler techniques in predicting PG and aortic valve area (AVA) in adults with AS.
• To compare Doppler-derived hemodynamic parameters with cardiac catheterization data.
• To assess the correlation between acceleration time/ejection time (AT/ET) ratio and AS severity.

Main Methods:

• Prospective evaluation of 54 adult patients with suspected AS undergoing cardiac catheterization.
• CW Doppler ultrasound using a 2 MHz transducer to record aortic jet velocities and left ventricular outflow tract (LVOT) flows.
• Calculation of Doppler PG using the modified Bernoulli equation and AVA using the continuity equation.
• Analysis of AT/ET ratio and comparison with catheterization-derived PG.

Main Results:

• The AT/ET ratio correlated significantly with peak aortic jet velocity (r=0.88) and catheterization PG (r=0.87) in patients with aortic regurgitation.
• Excellent correlation was observed between CW Doppler and catheterization for maximum PG (r=0.97, SEE 6 mmHg).
• Good correlation was found for mean PG between Doppler and catheterization (r=0.97, SEE 5.4 mmHg).

Conclusions:

• CW Doppler ultrasound is a reliable method for assessing PG in patients with AS.
• Doppler-derived AVA and PG measurements correlate well with cardiac catheterization data.
• The AT/ET ratio may provide additional information regarding AS severity.