GSTM1 and anemia: In conclusion, preoperative anemia (Hb < 13.1 g/dL, p = 0.033), reduced right ventricular systolic function (TAPSE < 20 mm, p = 0.017) and high serum TMAO levels (≥61.8 ng/mL, p = 0.006) are associated with a higher incidence of POAF (Table 9, Figure 3).