Abstract 11736: Anatomic Repair of Congenitally Corrected Transposition of the Great Arteries is Associated With Risk of Heart Block and ECMO, but Not Mortality

Introduction: Congenitally corrected transposition of the great arteries (CC-TGA) is characterized by atrioventricular and ventriculoarterial discordance with circulation remaining in series. The double switch operation and atrial switch with Rastelli are anatomic repairs of CC-TGA, achieving a systemic morphologic left ventricle. In contrast, physiologic repair (addressing associated lesions like ventricular septal defects and pulmonary stenosis) or no repair leave the right ventricle in the systemic position. Anatomic repair may confer superior longevity with increased upfront risk. We sought to determine if anatomic repair was associated with increased short-term risk of mortality, heart block, or extracorporeal membrane oxygenation (ECMO). Methods: Single-center retrospective cohort study of CC-TGA patients from 1990-2017. Cox proportional hazard analyses and Fisher’s exact test were performed. Results: Inclusion criteria were met by 54 patients, 21 anatomic repair and 33 physiologic/no repair. Median follow-up was 8.9 years (IQR 1.4-18.0) with no difference between cohorts (p=0.38). The anatomic repair cohort was more likely to have ventricular septal defects, 86% versus 33% (p<0.001) and pulmonary stenosis, 43% versus 15% (p=0.02). Mortality was low and did not differ significantly between cohorts (p=0.07). Probability of developing complete heart block was higher in the anatomic repair cohort (p=0.006), with no significant difference after adjusting for anatomy (HR 3.8, 95% CI 0.7-20.5). The anatomic repair cohort had an increased risk of ECMO (p=0.006). There was no difference in quantity of iterative operations (p=0.64). Conclusions: Anatomic repair of CC-TGA conferred a higher short-term risk of heart block and ECMO compared to the physiologic/no repair cohort, though risk of heart block was linked with anatomy. This upfront risk did not result in higher mortality in the anatomic repair cohort but long-term risk remains unknown.