Treatment of pulmonary arterial hypertension in congenital heart disease in Singapore versus the Netherlands: Age exceeds ethnicity in influencing clinical outcome

Abstract

Background Advanced treatment of pulmonary arterial hypertension (PAH) in congenital heart disease (CHD) is increasingly applied worldwide following the—mainly Western world based—international PAH-CHD guidelines. However, studies comparing clinical presentation and outcome after the initiation of PAH-specific treatment are lacking. We aimed to analyse this in a Singaporean and Dutch cohort of PAH-CHD patients. Methods Adult CHD patients starting PAH-specific therapy, enrolled in two nationwide registries, were analysed. Patients received phosphodiesterase-type-5 inhibitors, endothelin receptor antagonists, or a combination. Change in six-minute walk test (6MWT) during follow-up was analysed using linear mixed model analysis. Determinants for mortality were assessed using Cox proportional hazard analyses. Results A total of 74 patients, 45 Dutch (mean age 47 ± 14 years) and 29 Singaporean (mean age 41 ± 14 years) were analysed. Despite a lower 6MWT (312 versus 395 metres, p = 0.01) and peak VO2 (35 versus 49% of predicted, p = 0.01) at baseline in Singaporean patients, the treatment effect was similar in the two populations. Age at initiation of therapy (per 5 year lower age, ? = + 4.5, p = 0.017) was the strongest predictor of improvement in exercise capacity, corrected for ethnicity, baseline 6MWT, sex and CHD defect. Conclusions Patients from Singapore had a worse clinical performance at baseline compared with the PAH-CHD patients from the Netherlands. No relation between ethnicity and improvement in 6MWT after PAH-specific therapy was found. Age at initiation of PAH-specific therapy was the strongest predictor of treatment efficacy and mortality, emphasising the need for early initiation of treatment in these patients. © The Author(s) 2016.