Abstract 12914: Echocardiographic Assessment of Ventricular Stiffness in Single Right Ventricle Physiology: A Validation Study

Abstract

Background: Ventricular stiffness is associated with outcomes in patients with single right ventricle (SRV) physiology. However, echocardiographic (echo) assessments of ventricular stiffness are limited in this population. The objective of this study was to assess if echo measures of diastolic function are associated with invasive reference standard measures of ventricular stiffness derived from pressure-volume loop (PVL) analysis. Methods: Patients with SRV physiology undergoing pre-Fontan heart catheterization were prospectively enrolled. PVLs were obtained via microconductance catheters. The reference standard measure of ventricular stiffness, β, was obtained after balloon occlusion of the vena cavae. Echo measures were derived from spectral and tissue Doppler and 3D echo. Conceptually, patients with abnormal active ventricular relaxation and small end-diastolic ventricular volumes (EDV) are at risk for having increased passive ventricular stiffness. Therefore, the echo measurement of interest was lateral E:e’ divided by EDV indexed to body surface area (E:e’/EDVi). Results: 19 patients included in the study. Mean age was 4.1 ± 0.7 years. Median β was 0.022 mL -1 (IQR 0.012, 0.062). Median lateral E:e’/EDVi was 0.10 mL -1 /m 2 (IQR 0.07, 0.15). The correlation between lateral E:e’/EDVi and β was r = 0.65, p < 0.01 (Figure). No other correlations existed between echo measures of diastolic function and invasively derived ventricular stiffness. Conclusion: Lateral E:e’/EDVi correlates reasonably well with the reference standard measure of ventricular stiffness in SRV patients prior to the Fontan operation. The clinical utility of assessing lateral E:e’/EDV in SRV patients should be further explored regarding its potential to identify novel insights into the pathophysiology of SRV heart disease, detect changes in stiffness after medical/surgical intervention, and to investigate new echo predictors of outcome.