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.