Objectives: To investigate the long term effects of treatment with bosentan in childhood pulmonary arterial hypertension (PAH)

Methods: This retrospective case note study included 103 children treated with bosentan, with or without a prostanoid or sildenafil, between January 2002 and April 2008. 42 had Idiopathic PAH (IPAH) and 61 had Associated PAH (APAH), all with congenital heart disease. Haemodynamic data were recorded at baseline (n=79) and 20 +/-8 months after treatment initiation (n=17). 6-minute walk distance, WHO functional class, somatic growth and Quality of Life (SF10) were assessed at baseline and at regular intervals for up to 5 years. Survival estimates were determined for all 103 patients.

Results: The median duration of treatment was 36 months (range 6-77 months) with no untoward side effects. At the end of study only 21% with IPAH, remained on bosentan monotherapy, compared with 41% with APAH. Kaplan-Meier survival estimates at 1, 2 and 3 years were 96%, 89% and 83% respectively. Exercise tolerance improved. The six-minute walk distance increased from a baseline of 258 +/-127 meters (mean +/-SD, n=50) to 312m at 6 months (p<0.01, n=36), an increase maintained at 1,2 and 3 years (p<0.01for all; n=33,n=27,n=19 respectively). .Repeat cardiac catheterisation showed no deterioration in either pulmonary vascular resistance index (21v17units.m2at baseline) or pulmonary artery pressure (56v52mmHg at baseline).

Conclusion: Bosentan is safe and effective as a monotherapy or given in combination, as appropriate, in children with PAH.