Response: Still puzzling about a clear definition of pulmonary arterial hypertension in newborns

Prognostic Value of Change in Cardiac Index After Prostacyclin Initiation in Pediatric Pulmonary Hypertension

Invasive hemodynamic assessment remains the gold standard for the diagnosis of pediatric pulmonary hypertension and for longitudinal assessment of response to therapy. This analysis sought to describe the changes in hemodynamic variables after initiation of prostacyclin therapy and determine which changes bear predictive power of adverse clinical outcomes. A retrospective chart review of established patients at Cincinnati Children's Hospital with pulmonary arterial hypertension (PAH) who required prostacyclin therapy between 2004 and 2018 was performed. The baseline hemodynamic parameters at diagnosis as well as change in those parameters between initial catheterization and post-prostacyclin initiation catheterization were independent variables. Cox proportional hazard regression and recursive partitioning analysis were used to characterize which hemodynamic factors predicted the composite adverse outcome (CAO) defined as death, lung transplantation, or reverse Pott's shunt surgery. During the study period, 29 patients met inclusion criteria in which there were 7 CAOs: 4 deaths, 3 lung transplants, and 2 reverse Pott's shunts. Median time between catheterizations was 86 days and between the initiation of prostacyclin therapy and the second catheterization was 54 days. Cox regression revealed that only baseline pulmonary artery pressure (> 51 mmHg) and a failure to increase cardiac index illustrated statistically significant hazard for occurrence of the CAO (p < 0.01). These criteria significantly dichotomized the population in a Kaplan-Meier analysis into likelihoods of experiencing the CAO. While controlling for other hemodynamic variables, the absence of augmentation of cardiac index after the initiation of prostacyclin therapy is a valuable prognostic indicator of adverse PAH outcomes in pediatrics.

Pulmonary hypertension in paediatrics. A feasible approach to bridge the gap between real world and guidelines

Pulmonary hypertension (PH) is quite infrequent in paediatric age and its most common aetiologies include idiopathic pulmonary arterial hypertension, PH related to congenital heart diseases, bronchopulmonary dysplasia (chronic lung disease), persistence of pulmonary hypertension of the newborn, and congenital diaphragmatic hernia. The developed for adult patients PH classification shows limitations when applied to paediatric subjects, since the underlying causes are markedly different between the two ages. In 2011, the Pulmonary Vascular Research Institute Panama Task Force outlined the first specific paediatric pulmonary hypertensive vascular disease diagnostic classification, including 10 main categories and 109 subcategories, thus testifying PH complex pathophysiology during newborns/children growth and development. The unique, distinctive features of paediatric PH were recognized also during the fifth World Symposium on Pulmonary hypertension in 2013 and then confirmed in the recent 2018 sixth World Symposium. For the sake of uniformity, an attempt to adapt the adult classification to paediatric patients was made. However, all these commendable classifications are very complex and may be not of quick comprehension for clinicians. A clinical simpler and simplified method is now suggested, comprising only five groups: Neonatal, Cardiac, Developmental, Idiopathic, and Syndromic PH. This approach is not aimed at replacing the already existing classifications, but is mainly based on the kind of specialized physician (neonatologist, paediatric cardiologist, paediatrician, pulmonologist, general practitioner) who first faces and looks after the child with suspected PH. What is dramatically known is that paediatric PH is a severe disease which, when untreated or undertreated, may lead to increased morbidity and mortality.