Incidence and Risk Factors for Right Ventricular Outflow Tract Obstruction after the Arterial Switch Operation

Background The aim of this study was to evaluate the incidence and risk factors for the development of right ventricular outflow tract obstruction (RVOTO) after the arterial switch operation (ASO). Methods Between 1983 and 2014, a total of 688 patients underwent ASO. RVOTO was defined as any obstruction of the right ventricular outflow tract (RVOT) requiring reintervention. Results RVOTO developed in 79 patients (11%) at a median time of 3.8 years (range, 1 day-23.6 years) after ASO. Freedom from RVOT reintervention was 96 ± 1, 89 ± 1, and 83 ± 2% at 1, 10, and 25 years, respectively. Independent risk factors for the development of RVOTO in a Cox's regression model were side-by-side great arteries (p < 0.001), aortic arch anomalies (p < 0.001), use of a pericardial patch for augmentation of the coronary buttons (p < 0.001), and a peak gradient more than 20 mm Hg over the RVOT at discharge (p < 0.001). Conclusion The incidence of RVOTO after ASO is not negligible. Complex morphology, such as side-by-side great arteries and aortic arch anomalies influences the development of RVOTO.