Guideline implementation and early risk assessment in pulmonary arterial hypertension associated with congenital heart disease: A retrospective cohort study

Introduction Current guidelines emphasize that accurate risk stratification is important for patients with pulmonary arterial hypertension (PAH), however, few suggestions have been specified for PAH associated with congenital heart disease (PAH-CHD). Objectives The aim of this study was to propose an accurate and simple system based on current guidelines for risk stratification in PAH-CHD patients during 12-month follow-up. Methods We reviewed 288 Chinese PAH-CHD patients between January 2014 and December 2016 in this retrospective cohort study. The low-risk criteria according to 2015 European Society of Cardiology guidelines and the adverse events (AEs) during follow-up were collected. The association between low-risk criteria and AEs was assessed with Cox regression, and a simplified risk stratification system was proposed. Results There were 105 PAH-CHD patients included in the final analysis. Twenty-nine patients had AEs defined as death, initiation of new or combined medication treatment, or re-hospitalisation because of the PAH worsening. Among the low-risk criteria, WHO/NYHA functional class, 6-minute walking distance (6MWD), NT-proBNP and SvO(2) were significantly different between AE and AE-free groups. However, 6MWD (HR = 0.08, 95% CI: 0.03-0.19, P < 0.001) and NT-proBNP (HR = 0.35, 95% CI: 0.16-0.78, P = 0.01) were the only independent predictors of AEs in multivariable model. When taking them into a simplified system for risk stratification, the number of low-risk criteria at diagnosis discriminated the risk of AEs (P < 0.001). Conclusions Among the low-risk criteria proposed by current guidelines, 6MWD and NT-proBNP predicted AEs independently for PAH-CHD patients. Simplified risk stratification system by taking these two parameters numerically provides accurate prognostic information in PAH-CHD patients.