title: Quantifying aortic regurgitation by using the color Doppler-imaged vena contracta: a chronic animal model study.
abstract: BACKGROUND
  The aim of the present study was to evaluate the accuracy of determining aortic effective regurgitant orifice area (EROA) and aortic regurgitant volume by using the color Doppler-imaged vena contracta (CDVC).
  
  
  RESULTS
  Twenty-nine hemodynamically different states were obtained pharmacologically in eight sheep with surgically induced aortic regurgitation. Instantaneous regurgitant flow rates (RFRs) were obtained with aortic and pulmonary electromagnetic flowmeters (EFMs), and aortic EROAs were determined from EFM RFRs divided by continuous wave Doppler velocities. Color Doppler-derived EROAs were estimated by measuring the maximal diameters of the CDVC. Peak and mean RFRs and regurgitant volumes per beat were calculated from vena contracta area continuous wave diastolic Doppler velocity curves. Peak EFM-derived RFRs varied from 1.8 to 13.6 (6.3+/-3.2) L/min (range [mean+/-SD]), mean RFRs varied from 0.7 to 4.9 (2.7+/-1.3) L/min, regurgitant volumes per beat varied from 7.0 to 48.0 (26.9+/-12.2) mL/beat, and the regurgitant fractions varied from 23% to 78% (55+/-16%). EROAs determined by using CDVC measurements correlated well with reference EROAs obtained by using the EFM method (r=.91, SEE=0.07 cm2). Excellent correlations and agreements between peak and mean RFR and regurgitant volumes per beat as determined by Doppler echocardiography and EFM were also demonstrated (r=.95 to .96).
  
  
  CONCLUSIONS
  Our study indicates that the CDVC method can be used to quantify both aortic EROAs and regurgitant flow rates.
authors.affiliation: Oregon Health Sciences University, Portland, USA.
authors.forename: M
authors.initials: M
authors.lastname: Ishii
authors.forename: M
authors.initials: M
authors.lastname: Jones
authors.forename: T
authors.initials: T
authors.lastname: Shiota
authors.forename: I
authors.initials: I
authors.lastname: Yamada
authors.forename: R S
authors.initials: RS
authors.lastname: Heinrich
authors.forename: S R
authors.initials: SR
authors.lastname: Holcomb
authors.forename: A P
authors.initials: AP
authors.lastname: Yoganathan
authors.forename: D J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D000818:Animals; D001022:Aortic Valve Insufficiency / Q000150:complications / Q000000981:diagnostic imaging*; D002306:Cardiac Volume; D002908:Chronic Disease; D004195:Disease Models, Animal; D018618:Echocardiography, Doppler, Color / Q000379:methods* / Q000706:statistics & numerical data; D016014:Linear Models; D015588:Observer Variation; D012756:Sheep; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology