To determine the incidence, characteristics of, and risk factors contributing to the development of pulmonary hypertension in children with Down syndrome.

This retrospective, review of a large cohort (n = 1242) of children with Down syndrome receiving care at a specialized referral center evaluated clinical data and serial echocardiograms from a clinic database and electronic medical records. Pulmonary hypertension characteristics and comorbidities were reviewed. Pulmonary hypertension was considered transient if echocardiographic evidence of pulmonary hypertension resolved without recurrence, persistent if no resolution, and recurrent if evidence of pulmonary hypertension returned after a period of resolution.

The incidence of pulmonary hypertension in children with Down syndrome was 28% (n = 346). Median age at initial diagnosis was 5 days (range: 0-7067 days). Pulmonary hypertension was differentiated into transient (70%), persistent (15%), and recurrent (15%) disease. Median duration of transient pulmonary hypertension was 8 months (range: 0.1-130.2 months). Median age at recurrence was 2.5 years (range 0.2-11.5 years). Initial pulmonary hypertension diagnosis was classified as World Health Organization group I disease in 82%, with 45% associated with congenital heart disease (CHD), and 38% persistent pulmonary hypertension of the newborn (PPHN). The pulmonary hypertension recurrence rate was significant and similar for both those with initial PPHN (12%) and non-PPHN (16%). A majority (87%) of patients with recurrent pulmonary hypertension were classified as World Health Organization group III. Frequently identified comorbid conditions included CHD, obstructive sleep apnea, intermittent hypoxia, and recurrent pneumonia.

Pulmonary hypertension is common in children with Down syndrome, is typically transient, and related to CHD or PPHN but can recur in the setting of respiratory disease such as obstructive sleep apnea, intermittent hypoxia, and recurrent pneumonia.