Abstract
A more in-depth, refined definition of pulmonary arterial hypertension in newborns is needed http://ow.ly/DQH530nDaLz
To the Editor:
We read with close attention the report recently published in the European Respiratory Journal by Rosenzweig et al. [1].
We would like to congratulate the authors for their commendable effort, aimed at discussing recent advances, ongoing challenges and specific approaches in the care of children suffering from pulmonary arterial hypertension (PAH), and offer a few comments.
This article is focused on describing the state of the art and future perspectives in paediatric PAH, as formulated by the recent Paediatric Task Force of the 6th World Symposium on Pulmonary Hypertension. They are quite similar to the report of the 5th World Symposium (Nice 2013), in which the unique features of paediatric PAH were highlighted for the first time, but decidedly different from the classification proposed by the Pulmonary Vascular Research Institute Taskforce (Panama 2011) [2, 3].
We agree that the marked age-related differences regarding PAH aetiology, clinical presentation and outcomes require a different approach in children, especially in infants under the age of 3 months.
In this respect, we would like to add that in persistent PAH of the newborn, the most common cause of transient PAH at that age (involving almost two out of 1000 live and at term births), the criteria for diagnosis are very challenging. These are based on clinical (need for respiratory support because of a >10% difference between pre-ductal and post-ductal saturation OR more than two episodes of desaturation <85% over a 12 h period of clinical observation and notwithstanding underlying lung disease optimal medical treatment) as well as echocardiographic features (structurally normal heart; peak gradient of systolic pulmonary arterial pressure >35 mmHg OR estimated pulmonary arterial pressure greater than two-thirds of the systemic arterial pressure AND presence of right-to-left shunt across a patent foramen ovale and/or patent ductus arteriosus) [4, 5].
Echocardiography is undoubtedly the gold standard for diagnosis, because techniques such as cardiac catheterisation and cardiac magnetic resonance imaging to assess pulmonary vascular resistance, blood flow and myocardial function are currently not feasible in sick newborns [6].
Furthermore, it is the oxygenation index (OI), calculated as
OI = mean airway pressure × FIO2 / PaO2
where FIO2 is the inspiratory oxygen fraction (%) and PaO2 is the arterial oxygen tension (in mmHg), which is normally used in the paediatric intensive care unit to stratify the severity of hypoxic respiratory failure and prognosis related with persistent PAH. Oxygenation can be continuously and noninvasively monitored by means of pulse oximetry (SpO2), and the oxygen saturation index (OSI), calculated as
OSI = mean airway pressure × FIO2 × 100 / SpO2
can be another reliable way of assessing the severity of hypoxic respiratory failure [7].
Overall, in our view the above stated refined definition of PAH should be taken into account in newborns under the age of 3 months. We do think that a multidisciplinary team, involving neonatologists, paediatricians, cardiologists and respiratory specialists, should be totally committed to the development of specific diagnostic and clinical management strategies in this early life field.
Footnotes
Conflict of interest: G. Calcaterra has nothing to disclose.
Conflict of interest: V. Fanos has nothing to disclose.
Conflict of interest: P.P. Bassareo has nothing to disclose.
- Received January 3, 2019.
- Accepted January 19, 2019.
- Copyright ©ERS 2019