Introduction:
Mitraclip deployment creates a double orifice valve with multiple regurgitant jets making quantification of mitral regurgitation (MR) difficult.
Hypothesis:
Our objective was to evaluate the accuracy of double jet MR quantification by summation of individual jet 3D echo-derived vena contracta area (VCA) or 2D proximal isovelocity surface area (PISA) estimation of regurgitant volume (RV).
Methods:
In a pulsatile flow loop model, six valve constructs were evaluated with RV of 25 ml, 45 ml, and 65ml/beat. Regurgitant orifices tested were: a single circular hole (n=6), two symmetric circular holes (n=6), and an asymmetric configuration with a circular hole and an elliptical hole (n=6). RV was compared with true flow measurements from in vitro flow transducers. RV was calculated as: 1) PISA-Effective regurgitant orifice area x Doppler time velocity interval (TVI) or 2) VCA x Doppler TVI.
Results:
RV derived by PISA method correlated well with reference standard flow measures for both single orifice and double orifice valve constructs (R=0.96 vs R=0.90, p<0.0001, respectively). PISA-RV also demonstrated a good correlation to true RV when tested through symmetric or asymmetric double orifice disks (R=0.96 vs R=0.87,p<0.0001). 3D-VCA derived RV showed a superior correlation using the symmetric vs asymmetric disks (R=0.946 vs R=0.63,p<0.001).
Conclusions:
In a pulsatile model of double orifice MR, total RV is accurately measured by summation of PISA-derived RV or VCA -derived RV from each orifice. These methods deserve further evaluation in the clinical setting.
The first known use of the double-orifice valve technique for Ebstein anomaly, performed 30 years ago
