Pulmonary arterial hypertension in adult congenital heart disease: prevalence, outcomes and treatment patterns

Background Pulmonary arterial hypertension (PAH) is a progressive, life-threatening complication of congenital heart disease (CHD). We aimed to determine the burden of clinically relevant PAH in a well-characterised adult CHD population. Methods This retrospective cohort study included 35 235 adult CHD patients from the Australian National CHD Registry, of whom 392 had clinically significant PAH (mean± sd age 43.4±13.9) (prevalence 1.11%). We prospectively defined clinically significant PAH as 1) prescription of PAH-specific therapy and/or 2) known Eisenmenger syndrome. 330 patients (84.2%) received PAH pharmacotherapy during the study period and 193 patients (49.2%) had Eisenmenger syndrome, 62 (32.1%) of whom were untreated. Results During the study period, 141 (36.0%) patients died, PAH treatment was associated with a numerically lower risk of mortality (hazard ratio (HR) 0.74, 95% CI 0.49–1.11; p=0.22). Patients with moderate complexity CHD had a significantly higher risk of death than the mild group (HR 1.78, 95% CI 1.08–2.92; p=0.023), whilst severe complexity patients had >2.5 times the risk of death (p<0.001). At last follow-up, 211 (63.9%) of treated patients were prescribed monotherapy, 90 (27.3%) dual and 29 (8.8%) triple therapy. From initial treatment to last follow-up, 123 (37.3%) of the treated group had switched therapy, 100 (30.3%) died, 75 (22.7%) continued their initial pharmacotherapy, 25 (7.6%) added additional drugs and seven (2.1%) underwent transplantation. Conclusions Approximately 1.11% of a large adult CHD population had clinically significant PAH. Mortality is high (6.9% at age 30 years, 35.7% at age 50 years) and treatment has shifted towards increased utilisation of combination therapy.