title: Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava.
abstract: To evaluate a simple noninvasive means of estimating right atrial (RA) pressure, the respiratory motion of the inferior vena cava (IVC) was analyzed by 2-dimensional echocardiography in 83 patients. Expiratory and inspiratory IVC diameters and percent collapse (caval index) were measured in subcostal views within 2 cm of the right atrium. Parameters were correlated with RA pressure by flotation catheter within 24 hours of the echocardiogram (38 were simultaneous). Correlations between RA pressure (range 0 to 28 mm Hg), expiratory and inspiratory diameters and caval index were 0.48, 0.71 and 0.75, respectively. Of 48 patients with caval indexes less than 50%, 41 (89%) had RA pressure greater than or equal to 10 mm Hg (mean +/- standard deviation, 15 +/- 6), while 30 of 35 patients (86%) with caval indexes greater than or equal to 50% had RA pressure less than 10 mm Hg (mean 6 +/- 5). Sensitivity and specificity for discrimination of RA pressure greater than or equal to or less than 10 mm Hg were maximized at the 50% level of collapse. Thus, IVC respiratory collapse on echocardiography is easily imaged and can be used to estimate RA pressure. A caval index greater than or equal to 50% indicates RA pressure less than 10 mm Hg, and caval indexes less than 50% indicate RA pressure greater than or equal to 10 Hg.
authors.affiliation: University of California, San Francisco, Division of Cardiology, John Henry Mills Echocardiography Laboratory.
authors.forename: B J
authors.initials: BJ
authors.lastname: Kircher
authors.forename: R B
authors.initials: RB
authors.lastname: Himelman
authors.forename: N B
authors.initials: NB
authors.lastname: Schiller
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016275:Atrial Function; D001794:Blood Pressure / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology; D004452:Echocardiography / Q000379:methods; D005260:Female; D006321:Heart / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012119:Respiration; D014682:Vena Cava, Inferior / Q000502:physiology*