Direct quantification of dynamic changes of the mitral valve regurgitant orifice: Using 3-D echocardiography

We have shown that the mitral valve regurgitant orifice area (ROA) can be directly quantitated using 3D echo. The dynamic changes of the shape and size of the ROA during the cardiac cycle in pts with mitral valve prolapse have not been directly visualized. Method: To test the hypothesis that 3D echo can directly quantify dynamic changes in ROA, we reconstructed the mitral valve (TomTec, HP 2500) with 3⁰ gated acquisitions using a multiplane transesophageal probe in 18 pts (age 58 ± 9.5 yrs, 12 M) undergoing mitral valve repair. The ROA was displayed from a frontal annular view and measured by direct planimetry in each systolic frame. Results: The dynamic size and shape changes of the ROA were visualized in all pts. An average of 8.4 ± 2.4 systolic frames displayed the ROA: Mean ROA size, cm² (mean,SD,range) 0.59 ± 0.30 (0.10-1.1) Minimal ROA 0.29 ± 0.18 (0.04-0.61) Maximal ROA 0.97 ± 0.57 (0.19-2.2) Mean dynamic change 0.68 ± 0.51 (0.08-1.79) Relative mean change (%) 68 ± 0.18 (27-91) Variability between minimal and maximal ROA withhin pts across systole was significant (p <0.0001, t-test), as well as variability of dynamic ROA changes between pts (p < 0.0001, F-test). ROA shape changed from polygonal/slit-like in early and late systole to oval in mid systole. Conclusion: Direct 3D echo planimetry reveals significant dynamic and shape changes of ROA during the cardiac cycle withhin as well as between patients with mitral valve prolapse.