Cardiac Magnetic Resonance Findings and Their Association with Clinical Outcomes in Pediatric Pulmonary Arterial Hypertension: An Exploratory Study

<b>Background</b>: Cardiac magnetic resonance [CMR] is a non-invasive tool to assess ventricular function in pediatric pulmonary arterial hypertension [PAH]. However, CMR parameters in children remain underexplored. <b>Methods</b>: Thirty-six children with PAH were prospectively evaluated using CMR. Right and left ventricular volumetric and functional parameters, including right and left ventricular ejection fraction [RVEF, LVEF], right and left ventricular end-systolic volume indexed to body surface area [RVESVi, LVESVi], right ventricular mass index [RVMi], ventricular mass index [VMI], septal curvature duration index [SCDI], and regional area change [RAC], were assessed. Clinical variables included brain natriuretic peptide [BNP], New York Heart Association [NYHA] class, and six-minute walk distance [6MWD]. Correlations, logistic regression, and Kaplan-Meier analyses were performed to determine associated factors for mortality. <b>Results</b>: RVEF was negatively correlated with BNP [r = -0.538, <i>p</i> = 0.001], while no correlation was found with LVEF. Decreased RVEF and LVESVi and VMI were associated with mortality in univariate analysis. Patients with VMI > 0.75 or leftward septal shift had significantly lower one-year survival [<i>p</i> = 0.016 and <i>p</i> = 0.040, respectively]. SCDI and RAC were not associated with mortality. <b>Conclusions</b>: RVEF, LVESVi, and VMI are associated with mortality in pediatric PAH. BNP reflects right ventricular dysfunction. VMI and septal morphology are strong associated markers and may enhance risk stratification in children with PAH.