title: Effective mitral regurgitant orifice area: clinical use and pitfalls of the proximal isovelocity surface area method.
abstract: OBJECTIVE
  We attempted to determine the accuracy and pitfalls of calculating the mitral regurgitant orifice area with the proximal isovelocity surface area method in a clinical series that included patients with valvular prolapse and eccentric jets.
  
  
  BACKGROUND
  The effective regurgitant orifice area, a measure of lesion severity of mitral regurgitation, can be calculated by the proximal isovelocity surface area method, the accuracy and pitfalls of which have not been established.
  
  
  METHODS
  In 119 consecutive patients with isolated mitral regurgitation, effective regurgitant orifice area was measured by the proximal isovelocity surface area method and compared with measurements simultaneously obtained by quantitative Doppler and quantitative two-dimensional echocardiography.
  
  
  RESULTS
  The effective mitral regurgitant orifice area measured by the proximal isovelocity surface area method tended to be overestimated compared with that measured by quantitative Doppler and quantitative two-dimensional echocardiography (38 +/- 39 vs. 36 +/- 33 mm2 [p = 0.09] and 34 +/- 32 mm2 [p = 0.02], respectively). Overestimation was limited to patients with prolapse (61 +/- 43 vs. 56 +/- 35 mm2 [p = 0.05] and 54 +/- 34 mm2 [p = 0.014]) and was restricted to patients with nonoptimal flow convergence (n = 7; 137 +/- 35 vs. 84 +/- 34 mm2 [p = 0.002] and 79 +/- 33 mm2 [p = 0.002]). In patients with optimal flow convergence (n = 112), excellent correlations with both reference methods were obtained (r = 0.97, SEE 6 mm2 and r = 0.97, SEE 7 mm2, p < 0.0001).
  
  
  CONCLUSIONS
  In calculating the mitral effective regurgitant orifice area with the proximal isovelocity surface area method, the observed pitfall (overestimation due to nonoptimal flow convergence) is rare. Otherwise, the method is reliable and can be used clinically in large numbers of patients.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: M
authors.initials: M
authors.lastname: Enriquez-Sarano
authors.forename: F A
authors.initials: FA
authors.lastname: Miller
authors.forename: S N
authors.initials: SN
authors.lastname: Hayes
authors.forename: K R
authors.initials: KR
authors.lastname: Bailey
authors.forename: A J
authors.initials: AJ
authors.lastname: Tajik
authors.forename: J B
authors.initials: JB
authors.lastname: Seward
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000473:pathology*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000473:pathology*; D011446:Prospective Studies