Objectives: The arterial switch operation (ASO) shows excellent early and long-term results. The aim of the present study was to evaluate the incidence of right ventricular outflow tract (RVOT) obstructions after the ASO and determine its risk factors.
Methods: A total of 513 arterial switch operations were performed since 1983. Simple transposition of the great arteries (TGA) was present in 319 patients, 152 patients had an additional VSD and 42 patients had a Taussig-Bing (TB) anomaly.
Results: Out of 480 early survivors, 44 (9%) required an intervention for RVOT obstruction (surgical intervention, n=31) at a mean time of 3 years after the ASO. Most obstructions were beyond the pulmonary bifurcation (n=16, 36%), whereas 10 patients (22%) had a predominantly supravalvar obstruction, 6 patients (14%) had a subvalvar obstruction, 1 patient (2%) had a valvar obstruction and 11 patients (25%) had obstructions at different levels of the RVOT. Freedom from reintervention was better for simple TGA, compared to patients with TGA+VSD (p=0.02), and for patients with TB (p<0.001). The multivariate analysis identified only the repair of an additional aortic obstruction (p<0.001) as an independent risk factors.
Conclusion: A concern about the right ventricular outflow tract after the ASO is justified. Its development can affect different levels of the RVOT and might be avoided. Patients with an aortic obstruction have a higher risk of developing a RVOT obstruction and might benefit from a subaortic resection at time of ASO. Peripheral stenosis can be prevented by thorough dissection of the pulmonary arteries.