RA Pressure

ECHONOMY
Tools for Echocardiographic Calculations
Muhamed Saric, MD, PhD
New York University

RA Pressure

Scope

To estimate right atrial pressure (RAP) from the diameter of the inferior vena cava (IVC) in expiration, and the percentage decrease in IVC diameter with inspiration.

Technical Aspects

IVC diameter should be measure 1-2 cm proximal to the IVC/right atrial junction. If 2D images of IVC are recorded digitally, use 5-10 beats; shorter recording intervals may miss inspiration. If spontaneous inspiration does not lead to change in IVC diameter, ask the patient to sniff and rerecord IVC.

Note that trained athletes may have physiologically enlarged IVC; the table below for estimation of RAP does not apply.

Estimation of Right Atrial Pressure

RAP (mm Hg)	Diameter (cm)	Inspiratory Collapse
Volume Depletion	<1.2	Total
0-5 Normal RAP	1.2 - 1.7	> 50%
6-10	>1.7	> 50%
11-15		< 50%
> 15		None

Reference

Lang RM, Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, Picard MH, Roman MJ, Seward J, Shanewise JS, Solomon SD, Spencer KT, Sutton MS, Stewart WJ; Chamber Quantification Writing Group; American Society of Echocardiography's Guidelines and Standards Committee; European Association of Echocardiography. Recommendations for chamber quantification: a report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr. 2005 Dec;18(12):1440-63.

Kircher BJ, Himelman RB, Schiller NB. Noninvasive estimation of right atrial pressure from the inspiratory collapse of the inferior vena cava. Am J Cardiol 1990;66:493-6.