Please click here to obtain permission to reproduce this image.
Click on image to view larger version.
Figure 4 Plots of Dynamic Variations of MRFR, Regurgitant Velocity, and EROA in 3 Different Patterns of Dynamic MR
(A) Flat pattern with constant PISA radius in a patient with degenerative MR. (B) Convex pattern with midsystolic peak of PISA radius in a patient with post-myocarditis MR. (C) Concave pattern with midsystolic trough of PISA radius in a patient with functional MR. Reference mean EROA (ref) was determined as the mean of instantaneous EROAs (triangles), those being derived from superposition of M-mode PISA and continuous-wave Doppler signal and dividing instantaneous MRFR (squares) by the simultaneous continuous-wave Doppler velocity (circles) as shown in the left top and second top panel. The MRSV by PISA reference approach is derived from reference mean EROA x VTI. Values of calculated mean EROAs by PISA-VTI, M-mode PISA, and serial PISA were obtained by dividing calculated MRSV by VTI and superimposed to PISA reference values, respectively. Because MRSV results for PISA-VTI and simplified PISA were very similar, analysis of dynamic variations is only shown for PISA-VTI. Note that only the convex M-mode PISA pattern (B) is ideal for single-point PISA applications because instantaneous EROAs are relatively constant throughout the period of regurgitation. In the flat and concave patterns (A, C) there is a strong dynamic variation of instantaneous EROAs preventing correct estimation of mean EROA by single-point PISA. The concave pattern (C) causes the greatest error of single-point PISA, particularly when the largest PISA radius (encircled peak MRFR) during systole is used instead of midsystolic PISA radius (encircled midsystole MRFR). EROA = effective regurgitant orifice area; MRFR = mitral regurgitant flow rate; other abbreviations as in Figure 1.
|
