P0389 - Echocardiographically-Derived Septal Positional Angle to Gauge Right Ventricular Pressure Load

Background: Pulmonary hypertension is a rare disease that can have many long-term consequences, including death. Cardiac catheterization is the gold standard for measuring right ventricular systolic pressures (RVSP), but is invasive and has potentially deadly complications. Non-invasive echocardiographic parameters used to identify and monitor pulmonary hypertension only crudely approximate RVSP. The aim of this study was to create a quantifiable measure of RVSP using septal positioning that is easy to perform, reproducible with low inter-reader variability, and can accurately identify children with pulmonary hypertension who need further evaluation via cardiac catheterization.

Methods: This study was designed as a retrospective study of patients with and without pulmonary hypertension who had a transthoracic echocardiogram and cardiac catheterization. Patients undergoing atrial septal defect closure with normal pulmonary pressures represented controls. Echocardiograms were assessed for traditional parameters of RVSP, and corresponding catheterization data including pulmonary pressures were tabulated. Two blinded readers then calculated the “Echocardiographically-Derived Septal Positional Angle (EDSPA).” Inter-observer variability and concordance of the EDSPA measures was calculated using the sign of Pearson’s r and the ratio of standard deviations. Receiver operating characteristic curves were utilized to display the predictive ability of EDSPA to discriminate select groups.

Results: A total of 169 children were included in this study, of which 159 had useable echocardiographic data. 40 children were identified as having clinically-diagnosed pulmonary hypertension while 98 children had an atrial septal defect that was being closed in the cardiac catheterization laboratory. The mean age of patients was 7.1 years (SD=5.30), with a minimum age of 54 days and with a maximum of 19 years. Overall, 36% of patients were male and 64% female. Inter-observer variability between the two readers was small with a Pearson correlation coefficient of 0.838 (p <0.001). An EDSPA of ≤28.0° predicted a mean MPA pressure >25 mmHg (as measured by cardiac catheterization) with a 77% sensitivity and 80% specificity (AUC 0.8647). In addition an EDSPA ≤26.6° predicted a RV/LV systolic pressure ratio >0.5 (as measured by cardiac catheterization) with a 76% sensitivity and 80% specificity (AUC 0.8387).

Conclusions: EDSPA is a useful, non-invasive, and reproducible method of quantifying right ventricular systolic pressure that is easy to perform in post-processing of standard echocardiographic imaging. With a sensitivity and specificity near 80%, it has significant utility in screening for pulmonary hypertension and determining which patients should and should not undergo further invasive diagnostic testing.