987-103 Relationship of Mitral Regurgitant Orifice Area to Semiquantitative Indices of Regurgitant Severity: An Intraoperative Transesophageal Investigation

To better understand the relationship between quantitative measurements of mitral regurgitant orifice area (ROA) and traditional semiquantitative assessments based on color Doppler jet area, we studies 65 patients with mitral regurgitation (MR) using intraoperative transesophageal echocardiography.MethodMR was graded semiquantitatively on a 4 point scale, integrating information on jet size and morphology and pulmonary venous flow pattern. Blinded to the results of semiquantitative grading, ROA was measured as RSV ∫vdt, where RSV was regurgitant stroke volume, calculated as the difference in forward stroke volume through the mitral annulus and that obtained from thermodilution, and v was the mitral regurgitant velocity obtained by continuous wave Doppler.ResultsThere was a significant difference of mean ROA between 2+(0.18±0.08cm2), 3+(0.30±0.11cm2) and 4+MR (0.67±0.36cm2 p<0.01), with a significant correlation between ROA and MR grading throughout the patient population (r=0.79 p<0.0001). However, significant overlap was noted in patients graded in 2-3+range (Fig.). Jet characteristics predictive of small ROA within a given grade was central directed jets. Optimal group separation was obtained as a ROA of 0.30cm2.Conclusion1) While useful as a rapid general classification of MR severity, semiquantitative Doppler methods have significant limitations for precise characterization of mitral incompetence; 2) ROA is readily obtained in the operating room and aids in quantitative assessment of MR