Arterial switch for transposition with left outflow tract obstruction: outcomes and risk analysis.

BACKGROUND

The long-term results and indications of the arterial switch operation (ASO) for transposition of the great arteries (TGA) and anatomic left ventricular outflow tract obstruction (LVOTO) remain undetermined. The aims of this study were to determine long-term outcomes and prognostic factors in this specific population.

METHODS

Between 1986 and 2011, 55 patients with TGA and anatomic LVOTO underwent ASO. Anatomic LVOTO was defined as an echocardiographic peak LVOT gradient exceeding 20 mm Hg associated with an anatomic narrowing. Forty-three patients had a ventricular septal defect. Median follow-up was 7.9 ± 6.5 years (maximum, 25 years). Univariate and multivariate risk analyses for late LVOTO, aortic regurgitation, LVOT reintervention, and death were performed.

RESULTS

The early mortality rate was 11% (n = 6); 2 deaths were LVOTO-related. At the latest follow-up, 3 patients (5%) had a LVOTO, 7 (13%) had moderate aortic regurgitation, and 4 (7%) had LVOT reoperation. Actuarial freedom from LVOT reoperation was 90% ± 5% at 10 and 15 years. The mean LVOT peak gradient was 3 ± 9 mm Hg at the latest follow-up. A preoperative pulmonary valve z-score of less than -1.7 (odds ratio, 19; p = 0.02) and an atrioventricular valve-related LVOTO (odds ratio, 15; p = 0.02) are independent predictors of recurrent LVOTO. A preoperative pulmonary valve z-score of less than -1.8 is an independent predictor of LVOT reoperation (odds ratio, 17; p = 0.03). The LVOT gradient per se and the presence of ventricular septal defect or a bicuspid valve do not influence outcomes.

CONCLUSIONS

Long-term outcomes of ASO for patients with TGA and anatomic LVOTO are satisfactory in selected patients. A lower preoperative pulmonary valve z-score and complex multilevel atrioventricular valve-related LVOTO are independent predictors of recurrent LVOTO and LVOT reoperation. TGA/LVOTO patients with pulmonary valve z-score exceeding -1.8 and resectable valvular or subvalvular LVOTO, or both, should be candidates for ASO, regardless of the severity of the LVOT peak gradient.