155: Quantification of mitral regurgitation by calculation of regurgitant volume: 3D left ventricular echocardiography versus PISA

Abstract

Quantification of mitral regurgitation (MR) by echocardiography is well established using several echo or Doppler parameters in which effective regurgitation office area (ERO) and regurgitant volume (RV) are the most commonly used. However, hemispheric assumptions allowing application of proximal isovelocity area (PISA) may be erroneous due to complex mitral valve morphology (i.e. mitral valve prolapse). We hypothesized that 3D left ventricular echocardiography associated with pulse Doppler could obtain RV with high reliability for comparison of 2 methods (3D vs PISA) in presence of mitral regurgitation. Methods: First, in 50 patients without MR, we compared LV ejection volumes (LVEj) from a full volume 3D echocardiographic acquisition and 2D Simpson method to the aortic stroke volume (ASV) obtained by Pulsed Doppler for validation of the 3D approach. Second, we analyzed 50 patients with different degree MR for comparison of the two approaches and verification of PISA RV values. Inter and intra observer variabilities were assessed for all techniques. Results: Correlations and Bland&Altman methods gave high adequacy between 3D LVEj and ASV compared to 2D and ASV (respectively 3D, r=0.96, y=0.91x+4.8, mean error (ME) and 95% confidence interval of error (CIE) [−0.84±6 ml] and 2D, r=0.81, y=0.78x+5.8, [−5.41±16 ml]. Variabilities average for 3D LVEj was 6±3% and 15+/-5% for 2D. In patients with mitral regurgitation, RV from PISA and 3D LVEj were 23.1±12 ml and 24.5±11 ml (p=0.37) and the fractional regurgitation 32±13% and 33±12% (p=0.63). However, mean error measurement was −1.37 ml and 95% confidence interval of error was 17.90 ml showing high discrepancy between the two methods. By selecting a cut-off of 5, 10, 15 ml, numbers of patients with uncorrected measurements was 48.5, 17 and 8.5%. When using ASE 4 grades classification, 25,7% of misclassified patients was obtained with PISA. Conclusion: 3D LVEj method is robust and reliable for calculation of mitral regurgitant volumes with significant differences compared than those obtained with PISA which seems to be less adequate for all types of MR.