Calculation of aortic valve area in aortic stenosis

The left ventricular outflow tract (LVOT) diameter (red line), measured just under the aortic valve, is obtained from the long axis parasternal view (panel A); the diameter is 1.5 cm and the area 1.8 cm². Using the apical four-chamber view, the Doppler sample volume in the LVOT is obtained from a position that approximates the locus from which the diameter of the LVOT had been measured (panel B). Another approach uses the continuous wave Doppler, sampling the jet across the stenotic aortic valve in the apical four-chamber view (panel C); the peak velocity is 4.7 m/s, yielding a peak gradient of 88 mmHg, a mean gradient of 45 mmHg, a flow velocity integral (VTI) of 100 cm, and a valve area of 0.27 cm². With the Doppler probe over the right parasternal window, the stenotic jet shows a peak velocity of 5.4 m/s, a peak gradient of 117 mmHg, a VTI of 129 cm, and a valve area of 0.21 cm².