Calculation of pulsed Doppler left ventricular outflow tract regurgitant index for grading the severity of aortic regurgitation.

Measurement of the spatial extent of the regurgitant jet was performed in the left ventricular outflow tract (LVOT) with a 3 MHz two-dimensional echo-pulsed Doppler device, in order to assess the severity of aortic regurgitation on a quantitative basis. The procedure included: detection of diastolic disturbances in the LVOT and mapping of these disturbances in the LVOT. Length (L) and height (H) were measured with calculation of the product (L X H) in the long-axis view and width (W) in the short-axis view with calculation of the LVOT regurgitant index (LVOTRI) as follows: ([L X H] X W). Twelve normal subjects and a group of 83 patients, including 40 patients with aortic regurgitation proved by aortography, were investigated with this procedure. Diagnostic reliability ranged between 90% for specificity and 95% for sensitivity. Correlations between the grading provided by the LVOTRI and those provided by aortography on a three-grade scale showed a correlation coefficient between 0.67 (linear model, p less than 0.01) and 0.80 (exponential model), because of the high values of the index in cases of severe regurgitation. Reliability of the LVOT investigation in aortic regurgitation requires the use of information from two combined scan planes and quantitative rather than qualitative data. Main limitations of the procedure are due to the presence of associated mitral lesions.