Reoperation for right ventricular outflow tract obstruction after arterial switch operation for transposition of the great arteries and aortic arch obstruction

Abstract

OBJECTIVES: Right ventricular outflow tract obstruction (RVOTO) is one of the reasons for late reinterventions after repair of transposition of the great arteries (TGA) with aortic arch obstruction (AAO). The aim of the present study was to identify predictors of reoperation for RVOTO in patients who underwent arterial switch operation (ASO) and arch repair for TGA or Taussig-Bing anomaly with AAO. METHODS: Between 1977 and 2015, 45 patients [TGA/intact ventricular septum (IVS) 5, TGA/ventricular septal defect (VSD) 13, Taussig-Bing 27] with coarctation (21), arch hypoplasia (5), coarctation and hypoplasia (12) and aortic arch interruption (7) underwent ASO and arch repair. The median age at the ASO was 19 days (range, 1 day to 12.7 years). AAO was repaired concomitantly with ASO in 36 patients. Operation reports and 2D-echocardiographic data were retrospectively reviewed to determine the following parameters: position of the great arteries, coronary artery anatomy, and diameters of RVOT, aortic annulus, aortic sinotubular-junction, pulmonary annulus and transverse aortic arch previous to ASO. The median follow-up time was 6 years (range, 0-30 years). Four patients were lost to follow-up; reliable echo data were available in 24 subjects. Cox proportional hazard models were performed to examine predictors of reoperation for RVOTO. RESULTS: Thirty-day mortality rate after ASO was 13% (n = 6), and late mortality rate 9% (n = 4). Ten patients (TGA/VSD 2, Taussig-Bing 8) had 14 reoperations for RVOTO. One patient died after reoperation. Taussig-Bing anomaly was a significant predictor of reoperation for RVOTO [hazard ratio (HR) = 5.5, 95% confidence interval (CI) = 1.15-26.38, P = 0.033]. Higher preoperative aortic annulus Z-score significantly decreased the reoperation risk (HR = 0.6, 95% CI = 0.42-0.93, P = 0.020). In reoperated patients, the mean gradient across the RVOT reduced from 84 ± 12.2 mmHg prior to reoperation to 15.29 ± 13.70 mmHg at latest follow-up. CONCLUSIONS: Taussig-Bing anomaly and smaller preoperative aortic annulus diameter (Z-score) were significant predictors of reoperation for RVOTO in patients after ASO for TGA or Taussig-Bing anomaly with AAO. In Taussig-Bing hearts, the more complex anatomy often necessitates modifications of the operation technique, sometimes precluding RVOT relief at primary ASO. During follow-up, the possibility of recurrent RVOTO should always be considered in this specific patient population. Yet, in case of a reoperation for RVOTO, the surgical relief is in general effective.