Abstract 12812: A Diagnostic Algorithm to Exclude Elevated Right Atrial Pressure Using Echocardiographic Measurements of Inferior Vena Cava
Backgrounds: Elevated right atrial pressure (RAP) is closely associated with poor prognosis in both right and left heart failure. Echocardiographic measurement of the inferior vena cava (IVC) diameter and its respirophasic variation is commonly performed for non-invasive estimation of RAP. However, no previous study has sought the diagnostic algorithm to exclude elevated RA pressure accurately at echo laboratory.
Methods: We studied 370 stable patients (age: 56±16 year-old) who underwent elective right heart catheterization. Echocardiography was performed within 24 hours of hemodynamic evaluation. Maximum IVC diameter and minimum diameter after a sniff test was measured, from which a percentile collapse was obtained. Considering the difference in physique, the IVC variables are also indexed by body surface area (BSA). Receiver Operating Characteristic (ROC) curves were generated using data obtained to determine optimal cutoffs for prediction of RAP ≥10mmHg. In each variable, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were computed in the usual fashion.
Results: The ROC curves demonstrated that all of the IVC diameter parameters have fair discriminate ability (0.77-0.84) to predict elevated RA pressure. Minimum IVC diameter of 11mm, but not maximum diameter, showed best area under the curve (0.84). Furthermore, the diagnostic algorithm, with a combination of variables from minimum IVC diameter of 11mm and IVC percentile collapse of 33%, successfully excluded patients with RAP ≥10mmHg with 98% NPV (Table). Algorithms using IVC diameter indexed by BSA were similar to those without being indexed.
Conclusion: A combination of minimum IVC diameter and IVC collapse percentile has high NPV to exclude patients with elevated RAP. This algorithm with 98% NPV might be helpful to prompt clinical decision in the care of critically ill patients.
- © 2013 by American Heart Association, Inc.