Improved Risk Prediction Using a Refined European Guidelines Instrument in Pulmonary Arterial Hypertension Related to Congenital Heart Disease

The European guidelines advocate a goal-oriented treatment approach in pulmonary arterial hypertension (PAH), based on a comprehensive risk assessment instrument, which has been validated in several PAH subgroups. We investigated its discriminatory ability and explored tricuspid annular plane systolic excursion and revised thresholds to improve its predictability within the adult congenital heart disease (CHD) population. In total, 223 adults (42 ± 16 years, 66% women, 68% Eisenmenger) were enrolled from 5 European PAH-CHD expert centers. Patients were classified as low, intermediate, or high risk at the baseline visit and at follow-up within 4 to 18 months. By the general PAH guidelines instrument, survival did not differ between the risk groups (p-value not significant), mostly because of the skewed group distribution. Reclassifying patients using revised thresholds for N-terminal pro–brain natriuretic peptide and 6-minute walk distance (i.e., low, intermediate, and high as <500, 500 to 1,400, >1,400 ng/L and >400, and 165 to 400 and <165 m, respectively) and use of tricuspid annular plane systolic excursion (low, intermediate, and high as >20, 16 to 20, and <16 mm, respectively) significantly improved the discrimination between the risk groups at baseline and follow-up (p = 0.001, receiver operating characteristic increase from 0.648 to 0.701), reclassifying 64 patients (29%). Irrespective of follow-up risk group, survival was better for patients with higher proportions of low-risk variables. Improvement to a low-risk profile at a median of 9 months of follow-up provided improved survival compared with the survival of patients who remained in the low-risk group. In conclusion, the external validity of general risk instrument for PAH appeared to be of limited discriminatory value in patients with PAH-CHD. We propose a refined risk instrument with improved discrimination for PAH-CHD.