Vertebral-apex angle and postoperative pulmonary venous obstruction
Figure 3 shows the V-A angle before and after the operation. The V-A angle increased after the operation in all patients except one (from 35° [32°-38°] to 39° [33°-46°], P = 0.018; Fig. 3A ). Although no significant differences were noted in the preoperative V-A angles between the non-PVO and PVO groups (35° [27°-38°] vs. 34° [33°-38°], P = 0.78, Fig. 3B ), the postoperative V-A angle (36° [29°-38°] vs. 46° [45°-50°], P = 0.001, effect size = 0.83;Fig. 3C ) and the ratio (1.03 [0.98-1.07] vs. 1.27 [1.24-1.42], P = 0.001, effect size = 0.83; Fig. 3D ) were significantly larger in the PVO than those in the non-PVO group. The cut off values of the postoperative V-A angle and the ratio were 41° and 1.17, respectively (AUROC curve, 1.0; P=0.001 for each).