PREVALENCE AND MORPHOLOGY OF MAJOR AORTO-PULMONARY COLLATERAL ARTERIES (MAPCAS) IN TETRALOGY OF FALLOT WITH PULMONARY ATRESIA: A RETROSPECTIVE OBSERVATIONAL STUDY

Abstract

Background: Tetralogy of Fallot with pulmonary atresia is a complex congenital heart defect frequently associated with major aortopulmonary collateral arteries (MAPCAs), which significantly affect pulmonary blood supply and surgical strategy. Objective: To assess the prevalence and morphological characteristics of MAPCAs in patients with Tetralogy of Fallot with pulmonary atresia. Methods: This retrospective observational study analyzed patients evaluated between January 2020 and December 2024 at a tertiary cardiac center. Comprehensive clinical data and advanced imaging findings from cardiac catheterization and computed tomography angiography were reviewed to characterize MAPCA anatomy and pulmonary artery morphology. Results: Eighty patients were included, with a mean age of 3.8 ± 2.4 years. The mean number of MAPCAs was 3.2 ± 1.4 per patient, predominantly originating from the descending thoracic aorta (77.5%). Significant MAPCA stenoses were identified in 61.3% of cases. The mean MAPCA diameter was 4.2 ± 1.8 mm. Confluent central pulmonary arteries were present in 66.3% of patients. Native pulmonary artery indices showed a mean McGoon ratio of 1.4 ± 0.4 and mean Nakata index of 142.6 ± 58.3 mm²/m². A significant positive correlation was observed between MAPCA number and baseline oxygen saturation (r = 0.68, p < 0.001). Conclusion: MAPCAs exhibit marked anatomical heterogeneity in Tetralogy of Fallot with pulmonary atresia. Early comprehensive imaging is essential for characterizing MAPCA morphology and pulmonary artery indices to guide therapeutic planning.