Prediction of severity of isolated aortic regurgitation by echocardiography: An aortic regurgitation index study

Background: No single precise qualitative method is recommended for evaluating the severity of aortic regurgitation (AR). Quantitative methods for AR assessment are, typically, cumbersome and time-consuming. The purpose of this study was to develop a more comprehensive method for predicting the severity of AR. Methods: In all, 79 patients with normal left ventricular systolic function and at least mild AR were included in this prospective study. The standard references for evaluating AR severity were quantitative methods. The AR index consisted of 5 echocardiographic parameters: jet width ratio, vena contracta width, pressure half-time, jet density, and diastolic flow reversal in the descending aorta. Each parameter was scored on a 3-point scale from 1 to 3. The AR index was calculated;as the sum of each score divided by the number of parameters. Thus, an increasing AR index score from 1 to 3 was indicative of increasing regurgitation. Result: The study demonstrated that the numeric value of AR index increased proportionately to the quantitative grading of AR severity, and proved to be an accurate predictor for AR severity. A 1.8 threshold for the AR index offered a high level of sensitivity and negative predictive value for severe AR. The possibility of missing severe AR was low with AR index less than 1.8. A 2.6 threshold for the AR index provided high specificity and positive predictive value for severe AR. The possibility of diagnosing severe AR was extremely high with AR index of 2.6 or more. Conclusion. AR index provided a more comprehensive method for predicting the degree of AR severity in this study. We suggest that the AR index should be considered for any evaluation of the severity of AR.