Case example of a 17-year-old patient with severe dilated cardiomyopathy and functional MR. (A, top) The PISA-VTI method; midsystolic PISA at a Nyquist setting of –15.4 cm/s in 4-chamber view with PISA radius r for calculation of MRSV (14.9 ml) (right). (A, bottom) Continuous-wave Doppler spectrum of regurgitant flow with determination of peak velocity (V_max) and VTI. (B) Serial PISA method. Six serial PISAs throughout systole at a frame rate of 18 frames/s, with calculated MRSV of 22.2 ml (right). Note the decrease of PISA size in midsystole. (C) M-mode PISA method. M-mode registration of PISA with typical midsystolic trough. The gray curved line indicates the leaflet level. The white box illustrates volumetry of the M-mode PISA by method of discs (using Philips EnConcert offline analysis software, Philips Medical Systems, Andover, Massachusetts) to derive r² _mean. Calculated MRSV was 27.9 ml. Length (PISA) = length of M-mode proximal isovelocity surface area in cm; MR = mitral regurgitation; MRSV = mitral regurgitant stroke volume; PISA = proximal isovelocity surface area; t (PISA) = time of mitral regurgitation duration in seconds; Vol (PISA) = M-mode proximal isovelocity surface area volume in ml; VTI = velocity–time integral.

(Left) Linear regression analysis; (right) Bland-Altman analysis of agreement. Data point symbols and regression line patterns: triangles and dash-dot line = convex dynamic MR pattern; squares and long-dashed line = flat pattern; circles and short-dashed line = concave pattern; solid line = total regression line over all 73 measurement results; thin medium-dashed line = line of identity (y = x). MRI = magnetic resonance imaging; other abbreviations as in Figure 1.

For data point symbols and regression line patterns, see Figure 2. Abbreviations as in Figure 1.

(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.