title: Valve orifice area in aortic stenosis evaluated by planimetry, Gorlin and continuity equations: a prospective study.
abstract: In evaluation of the severity of aortic valve stenosis, multiple parameters can be determined. All of them, except valve orifice area, are influenced by other factors such as cardiac output, heart rate or aortic insufficiency.
  
  
  OBJECTIVE
  This is a prospective study which proposes, in the determination of the valve orifice area in aortic stenosis, to evaluate the accuracy of and correlation between three methods--planimetry by multiplane transesophageal echocardiography, the continuity equation by transthoracic echocardiography, and invasive measurement using the Gorlin formula.
  
  
  METHODS
  Forty-five patients with known calcified valvular aortic stenosis 27 men, mean age 70 +/- 10 years, (range 27-82), were studied. In all patients the area was determined by planimetry and by the continuity equation. In 25 (56%) patients invasive measurements were obtained using the Gorlin formula.
  
  
  RESULTS
  Evaluation of the valve orifice area by planimetry was easily performed and did not prolong the duration of the exam, except in five patients (11%). The area determined by the continuity equation had a mean value of 0.74 +/- 0.25 cm2, by planimetry 0.74 +/- 0.24 cm2 and by the Gorlin formula 0.65 +/- 0.17 cm2. Correlations between areas obtained by the three methods used were: continuity equation and planimetry 0.82; continuity equation and Gorlin formula 0.51; and planimetry and Gorlin formula 0.80. Concordance analysis (Bland and Altman's method) gave mean (Mn) values for the differences in the areas determined by the Gorlin formula and the continuity equation of 0.01 +/- 0.15 cm2 (Mn - 2SD = -0.29, Mn + 2SD = 0.30). The estimated value by the Gorlin formula and planimetry was 0.02 +/- 0.10 (Mn - 2SD = -0.19, Mn + 2SD = 0.23).
  
  
  CONCLUSIONS
  1) Planimetry of the valve orifice area by transesophageal echocardiography is feasible and does not prolong the duration of the exam in the majority of patients. 2) The strong correlation and the results of concordance analysis, in the determination of valve orifice area, between traditional invasive methods and planimetry, support the use of this noninvasive method in clinical practice.
authors.affiliation: Serviço de Cardiologia, Hospital Garcia de Orta, Almada.
authors.forename: Isabel
authors.initials: I
authors.lastname: João
authors.forename: Carlos
authors.initials: C
authors.lastname: Cotrim
authors.forename: J A
authors.initials: JA
authors.lastname: Duarte
authors.forename: Paula
authors.initials: P
authors.lastname: Fazendas
authors.forename: Carlos
authors.initials: C
authors.lastname: Catarino
authors.forename: Helder
authors.initials: H
authors.lastname: Pereira
authors.forename: Fernando
authors.initials: F
authors.lastname: Matias
authors.forename: L Moura
authors.initials: LM
authors.lastname: de Oliveira
authors.forename: Manuel
authors.initials: M
authors.lastname: Carrageta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014463:Ultrasonography