title: A method for estimating aortic regurgitant effective orifice area by digital Doppler color flow mapping.
abstract: OBJECTIVE
  Although non-invasive assessment of the severity of aortic regurgitation (AR) is important, quantitative evaluation of AR can be difficult in clinical settings. Most Doppler echocardiographic methods have been compared with angiographic grading of AR severity. However, while aortic angiography is used widely for grading AR severity, the method is only semi-quantitative. A computed semi-automatic digital color Doppler method has recently been described for calculating stroke volume and cardiac output. The study aim was to develop a method of evaluating AR severity by using a digital automated color Doppler method (ACM) along with continuous wave (CW) Doppler for estimating aortic regurgitant effective orifice area.
  
  
  METHODS
  A total of 22 different hemodynamic conditions were studied in six sheep. Regurgitant volumes (RV) were determined by electromagnetic flowmetry (EM) and by ACM. AR effective orifice areas (EOAs) were determined by dividing each of the RVs by the time integrals of the AR continuous wave velocities. AR EOAs by ACM were compared with those obtained by EM and with other EM indices of regurgitant severity. ACM was accurate for quantifying AR EOAs (r = 0.96).
  
  
  CONCLUSIONS
  Calculated AR EOA correlated well with peak AR flow and regurgitant fraction by EM. The combined ACM/CW Doppler method can be useful for estimating non-invasively the aortic regurgitant EOA and for evaluating the severity of AR.
authors.affiliation: Laboratory of Animal Medicine and Surgery, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: M
authors.initials: M
authors.lastname: Chikada
authors.forename: T
authors.initials: T
authors.lastname: Shiota
authors.forename: S
authors.initials: S
authors.lastname: Aida
authors.forename: I
authors.initials: I
authors.lastname: Yamada
authors.forename: D J
authors.initials: DJ
authors.lastname: Sahn
authors.forename: M
authors.initials: M
authors.lastname: Jones
mesh_terms: D019412:Anatomy, Cross-Sectional; D000818:Animals; D001011:Aorta / Q000033:anatomy & histology*; D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging*; D004195:Disease Models, Animal; D018618:Echocardiography, Doppler, Color / Q000379:methods*; D006439:Hemodynamics; D016014:Linear Models; D012756:Sheep