Reproducibility of Proximal Isovelocity Surface Area, Vena Contracta, and Regurgitant Jet Area for Assessment of Mitral Regurgitation Severity

OBJECTIVES The aim of this study was to evaluate the interobserver agreement of proximal isovelocity surface area (PISA) and vena contracta (VC) for differentiating severe from nonsevere mitral regurgitation (MR). BACKGROUND Recommendation for MR evaluation stresses the importance of VC width and effective regurgitant orifice area by PISA measurements. Reliable and accurate assessment of MR is important for clinical decision making regarding corrective surgery. We hypothesize that color Doppler-based quantitative measurements for classifying MR as severe versus nonsevere may be particularly susceptible to interobserver agreement. METHODS The PISA and VC measurements of 16 patients with MR were interpreted by 18 echocardiologists from 11 academic institutions. In addition, we obtained quantitative assessment of MR based on color flow Doppler jet area. RESULTS The overall interobserver agreement for grading MR as severe or nonsevere using qualitative and quantitative parameters was similar and suboptimal: 0.32 (95% confidence interval [CI]: 0.1 to 0.52) for jet area-based MR grade, 0.28 (95% CI: 0.11 to 0.45) for VC measurements, and 0.37 (95% CI: 0.16 to 0.58) for PISA measurements. Significant univariate predictors of substantial interobserver agreement for: 1) jet area-based MR grade was functional etiology (p = 0.039); 2) VC was central MR (p = 0.013) and identifiable effective regurgitant orifice (p = 0.049); and 3) PISA was presence of a central MR jet (p = 0.003), fixed proximal flow convergence (p = 0.025), and functional etiology (p = 0.049). Significant multivariate predictors of raw interobserver agreement >= 80% included: 1) for VC, identifiable effective regurgitant orifice (p = 0.035); and 2) for PISA, central regurgitant jet (p = 0.02). CONCLUSIONS The VC and PISA measurements for distinction of severe versus nonsevere MR are only modestly reliable and associated with suboptimal interobserver agreement. The presence of an identifiable effective regurgitant orifice improves reproducibility of VC and a central regurgitant jet predicts substantial agreement among multiple observers of PISA assessment. (J Am Coll Cardiol Img 2010;3:235-43) (C) 2010 by the American College of Cardiology Foundation