Combined CMR and catheterization data in determining right ventricular-arterial coupling in children and adolescents with pulmonary arterial hypertension

Methods This retrospective study included subjects with PAH who a cardiac magnetic resonance (CMR) study within 14 days of cardiac catheterization between January 2009-August 2013. The effective elastance (Ea, index of arterial load) and right ventricular maximal end-systolic elastance (Emax, index of contractility) were determined by a combination of CMR and hemodynamic data. Ea is defined as (mean pulmonary arterial pressure minus pulmonary capillary wedge pressure)/stroke volume. Emax is defined as mean pulmonary arterial pressure/ end systolic volume. Ea/Emax ratio was derived. Additionally, a measure of non-invasive ventricular arterial coupling (assuming PWCP is insignificant, making Ea/ Emax = end systolic volume/stroke volume) was derived from only CMR. Pulmonary vascular resistance indexed (PVRi) and pulmonary vascular reactivity, as defined by Barst criteria (decrease in mean pulmonary artery pressure of > 20%, unchanged/increased cardiac index, and decreased/unchanged pulmonary to systemic vascular resistance ratio), were also determined. Pearson correlation coefficients were calculated between PVRi and Ea, Emax, and Ea/Emax. Receiving operating characteristic (ROC) curve analysis determined the diagnostic value of Ea/Emax in predicting vascular reactivity.