Pulmonary outflow obstruction protects against heart failure in adults with congenitally corrected transposition of the great arteries

BackgroundPulmonary outflow tract obstruction (POTO) reduces systemic atrioventricular valve (SAVV) regurgitation severity in congenitally corrected transposition of the great arteries (ccTGA). Therefore, pulmonary artery banding is proposed as a palliative intervention. We aimed to investigate the effect of native or surgically induced POTO on event-free survival, defined as the composite of all-cause mortality, heart transplantation, or congestive heart failure (CHF).Methods and resultsPatients with ccTGA (n = 62; median age 27.5 (IQR 18.4-39.4) years; 39% with POTO) were selected from the Adult Congenital Heart Disease database of a tertiary hospital. At first visit, SAVV regurgitation ≥ 3/4, systemic RV dysfunction ≥ moderate, and CHF were present in 26%, 26%, and 15% of patients, respectively. Over a mean follow-up time of 10.1 ± 6.1 years, all-cause mortality, rate of heart transplantation, and CHF were 18%, 8% and 40%, respectively. SAVV regurgitation (HR: 1.99; 95% CI: 1.01-3.92; P = 0.048) and systemic RV dysfunction severity (HR: 1.89; 95% CI: 1.05-3.37; P = 0.033) were associated with the composite endpoint, independently of age at baseline, POTO, Ebstein-like malformation, and systemic RV dilatation. Patients with POTO had lower risk for developing SAVV regurgitation ≥ 3/4 (HR: 0.18; 95% CI: 0.05-0.58; P = 0.004) and moderate systemic RV dysfunction (HR: 0.34; 95% CI: 0.15-0.78; P = 0.011). When POTO was present, the mean progression-free interval for the composite endpoint increased from 11.2 to 18.1 years (P = 0.035).ConclusionsPOTO is associated with an improved event-free survival in adults with ccTGA.