Influence of apical position on the left ventricular outflow tract obstruction in congenitally corrected transposition

Abstract Background The right ventricle has a proclivity to wrap around the left ventricle outflow tract (LVOT) in congenitally corrected transposition (CCT) patients with apicocaval ipsilaterality, which may influence the outcome of the double switch operation (DSO). The goal of this study was to determine if the LVOT is compressed by the right ventricle in this setting. Methods A total of 103 patients with CCT were divided into four groups according to ventricular looping and apical position, including Group A (D-loop and levocardia), Group B (L-loop and dextrocardia), Group C (D-loop and dextrocardia), and Group D (L-loop and levocardia). Computed tomography was used to define left-right laterality and ventro-dorsal relationship of the LVOT. Results Apicocaval ipsilaterality was found in 57 patients (Group A, n  = 25; Group B, n  = 32), in whom the right ventricle was found to wrap around the LVOT. Among them, 49 (86%) had LVOT obstruction. In 46 patients without apicocaval ipsilaterality (Group C, n  = 10; Group D, n  = 36), 31 had LVOT obstruction (67.4%). LVOT obstruction was more prone to occur in patients with apicocaval ipsilaterality compared with those without ( p  = 0.025), and was more significant in the situs solitus ( p  = 0.058) than in situs inversus ( p  = 0.547). Conclusions LVOT obstruction was prone to occur in CCT patients with situs solitus and apicocaval ipsilaterality (Group B). The ventricular outflow patency was influenced by apical position, which should be considered to avoid a posterior ventricular outflow tract from compression after DSO.