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Quantification of mitral regurgitant flow using proximal isovelocity surface area method: a transesophageal
1Department of Anesthesiology and General Intensive Care, University Hospital of Vienna, Austria.
Objective:
To investigate the usefulness of the color Doppler proximal isovelocity surface area (PISA) method, compared with the jet area method, in determining the severity of mitral regurgitation in the perioperative period using angiographic grading as a reference method.
Design:
Randomized, controlled prospective study.
Setting:
Single university hospital.
Methods:
Thirty-three patients with native mitral valve insufficiency of different grade were studied. The color jet area in the left atrium, as well as PISA regurgitant stroke volume (RSV), were established. PISA RSV was calculated using a formula derived from previous in vitro and human studies: RSV = 2 pi r2 x v x RTVI/RPFV x (inlet angle/180 degrees), in which r is the radial distance between the first aliasing contour (red/blue interface); v is the aliasing velocity that is read from the color bar; RTVI is the time-velocity integral of the regurgitant jet from the continuous wave Doppler recordings; and RPFV is the corresponding peak flow velocity of the continuous wave regurgitant jet.
Results:
The rank correlation coefficient between the angiographic grade of mitral regurgitation and the PISA method was rsp = 0.89 (p < 0.0001), and for the jet area was rsp = 0.44 (p < 0.01). There was close concordance between angiographic and PISA measurements of RSV (r = 0.92, p < 0.0001). Further, scatterplot of difference between the two measurements plotted against the mean of measurements showed good agreement.
Conclusions:
It was concluded that in patients with mitral regurgitation during the perioperative period, the PISA method is more suitable than the jet area method to determine the severity of mitral regurgitation, and only it provides a reliable technique to differentiate between grade I-II mitral regurgitation in patients with eccentric regurgitant jet and grade III-IV mitral regurgitation in patients with jet size that is bigger than transesophageal echocardiography left atrial size.