ObjectiveTo investigate the feature of the angulation between left pulmonary artery (LPA) and main pulmonary artery (MPA) and its relationship to pulmonary artery development in patients with tetralogy of Fallot (TOF).MethodsA total of 101 TOF patients in West China Hospital from 2014 to 2018 were enrolled in a TOF group, including 62 males and 39 females, aged 6.8 (0.3-45.8) years, and another 20 patients without basic cardiac diseases at the same stage were enrolled in a control group, including 10 males and 10 females, aged 6.9 (0.3-54.0) years. Diameters of LPA, right pulmonary artery (RPA) and MPA, the angulation between LPA and MPA (MPA-LPA), McGoon ratio, and Nakata index were measured and compared between the two groups. The relationship between the above data and MPA-LPA angulation was also analyzed.ResultsThe average MPA-LPA angulation was smaller in the TOF group than that in the control group (113.63° vs. 128.45°, P=0.001 8). The MPA Z score was also smaller in the TOF group than that in the control group (0.46 vs. 2.75, P=0.000 4). No relationship was found by correlation analysis between the MPA-LPA angulation and MPA Z score or LPA Z score in the control group (P=0.239 6, 0.114 7) and the TOF group (P=0.759 3, 0.242 7). The McGoon ratios (2.22±0.72, 2.43±0.94, P=0.340 0) and Nakata index (359.3±294.24, 395.52±329.31, P=0.650 0) were not significantly different between the two groups.ConclusionThe angulation of LPA-MPA and MPA Z score are smaller in the TOF group than those in the control group. There is no relationship between MPA-LPA angulation and pulmonary artery diameters. The LPA-MPA angulation should not be considered as an influence factor for LPA development and trans-annular patch surgery.