Background: Pulmonary arterial hypertension (PAH) is a significant consequence of congenital heart disease (CHD). Its presence and severity is associated with increased morbidity and mortality. 

Objectives: To evaluate the clinical and demographic characteristics of adults with congenital heart diseases (ADCHD) and PAH at a single center. 

Methods: A prospective registry of all patients with PAH was conducted between 2009 and 2015. 

Results: Thirty-two patients were identified. The mean age at the last visit was 44 years (range 19–77 years). The prevalence of PAH among all ADCHD patients was 6% (95% confidence interval 4.3%–8.4%). A much higher prevalence (53%) was found in patients with Down syndrome. Most patients with PAH had moderate or severe disease. Fifteen patients (47%) were treated with pulmonary vasodilators and 6 (19%) with combination therapy. The average World Health Organization functional class was 2.6. Morbidity included cerebral vascular accident or transient ischemic attack in 22% (mostly in patients with right-to-left shunt) and arrhythmia in 37% of the patients. During a median follow-up of 3.5 years, 5 patients (15.6%) died. Of 13 women with no mental retardation, 11 were or had been married and all had children (between 1 and 13, mean 3.3). 

Conclusions: Patients with congenital heart disease and PAH have significant morbidity and mortality. PAH is more prevalent in patients with Down syndrome. While pulmonary pressure during the reproductive years was not always known, 27% of women with PAH at the time of the study were multiparous.