5 th International Conference of Neonatal and Childhood Pulmonary Vascular Disease: San Francisco, California, USA, 9–10 March, 2012

In the current era of evolving treatment options, there is a need for reliable prognostic parameters in pediatric pulmonary arterial hypertension (PAH). The purpose of this study was to determine the prognostic value of pulmonary stroke volume (PSV) and pulmonary arterial compliance (stroke volume /pulse pressure; PAC) in pediatric PAH. Cardiac catheterization data of 50 consecutive children with idiopathic/hereditary PAH (iPAH/HPAH; n=30) or PAH associated with congenital heart disease (PAH-CHD; n=20) were retrospectively reviewed. PSVi and PACi (both indexed for body surface area) were determined at baseline and during acute vasodilator response tests (AVR). Survival analyses were performed using Kaplan Meier curves and (multivariate) Cox Regression analyses, using death or lung transplantation as endpoints. PSVi (38.4±25.4 ml/ m2) and PACi (0.97±0.83 ml/mmHg/m2) were both age-independent and did not differ between iPAH/HPAH and PAH-CHD. During AVR, PSVi increased to 45.6±25.4 ml/m2 (P<0.01) and PACi to 1.80±2.87 ml/mmHg/ m2 (P<0.01). In univariate analysis, higher baseline PSVi and PACi were associated with improved outcome. In multivariate analysis, corrected for diagnosis, systemic to pulmonary shunt, gender, age, drug-treatment, mean right atrial pressure, cardiac index and pulmonary vascular resistance index, baseline PSVi independently predicted prognosis (HR 0.25 [95% CI 0.07-0.88] per SD P=0.03); in contrast, PACi did not predict prognosis. PSVi and PACi during AVR did not have additional prognostic value. Baseline PSVi is a strong independent predictor for prognosis in pediatric PAH and may be used to identify higher-risk patients and guide therapy.