Comparison of semiquantitative and quantitative assessment of severity of aortic regurgitation: Clinical implications

Background: Recent studies have emphasized the importance of quantitative assessment of the degree of aortic regurgitation (AR). However, semiquantitative methods have remained mainly used despite their unclear diagnostic value. The aim of this study was to define the sensitivity and specificity of semiquantitative methods compared with the proximal isovelocity surface area method as a reference for the diagnostic of severe AR. Methods: The degree of AR was evaluated using the proximal isovelocity surface area method and four semiquantitative measurements (left ventricular cardiac output, pressure half-time, diastolic flow reversal, and vena contracta) in 224 patients with a wide range of AR severity. Results: The mean effective regurgitant orifice area was 25 ± 14 mm ² (range, 3-69 mm ²), the mean regurgitant volume was 57 ± 31 mL (range, 9-183 mL), and 100 patients (44%) had severe AR (effective regurgitant orifice area ≥ 30 mm ² or regurgitant volume ≥ 60 mL). Overall, semiquantitative methods had good specificity but poor sensitivity, except the vena contracta, which had good sensitivity and specificity. Sensitivity, specificity, and positive and negative predictive values of the recommended thresholds for severe AR of the four semiquantitative methods were 53%, 89%, 77%, and 73% for left ventricular cardiac output ≥ 10 L/min; 12%, 100%, 100%, and 52% for pressure half-time < 200 msec; 45%, 87%, 79%, and 60% for diastolic flow reversal ≥ 18 cm/sec; and 81%, 83%, 78%, and 85% for vena contracta ≥ 6 mm, respectively. Conclusions: For the assessment of AR severity, current thresholds appear specific but poorly sensitive, except for vena contracta, which provides good discriminative value. Semiquantitative methods should be integrated into the comprehensive evaluation of AR severity, but severe AR should not be excluded only on the basis of semiquantitative criteria. These results emphasize the need for the quantitative assessment of AR severity.