To define the clinical utility of the color Doppler proximal isovelocity surface area
(PISA) method for estimating regurgitant stroke volume (SV), 160 regurgitant lesions
were evaluated in 104 patients with mitral (MR), aortic (AR), and tricuspid (TR) regurgitation.
Regurgitant SV by PISA was calculated as 2 pi R2 x V x (time-velocity integral/peak
flow velocity), where R is the radius corresponding to the first blue-red interface
velocity of the maximal PISA during the cardiac cycle. The time-velocity integral
and peak flow velocity from the continuous-wave Doppler recording of the regurgitant
jet were used to correct PISA for phasic variations in regurgitant flow. Fifteen lesions
were excluded because of difficulty in tracing the continuous-wave Doppler regurgitant
curve. Among 145 remaining regurgitant lesions, PISA was measurable in 50 (78%) of
64 cases of MR and 24 (69%) of 35 cases of TR but in only 12 (26%) of 46 cases of
AR (p < 0.001). Regurgitant SV by PISA correlated modestly well with jet area/atrial
area in all atrioventricular valve lesions (MR: r = 0.55; TR: r = 0.65; p < 0.001).
However, the correlation improved if only central jets were considered (MR: r = 0.70;
TR; r = 0.75; p < 0.001). These findings are not unexpected because jet area/atrial
area underestimates the true severity of regurgitation in cases of eccentric (wall-impinging)
jets. PISA was detected in all severe cases of regurgitation but in only 64% of cases
of mild MR, 45% of cases of mild TR, and 6% of cases of mild AR (p < 0.01). The color
Doppler PISA method is clinically useful in estimating regurgitant SV in MR and TR,
including mild cases, but is less useful in AR.