GSTM1 and anemia: 4109 enrolled patients divided into three groups based on their pre-procedural hemoglobin (Hb) level: Hb < 100 mg/L represented moderate-severe anemia; 100 mg/L ≤ Hb < 120 mg/L for women and 100 mg/L ≤ Hb < 130 mg/L for men represented mild anemia; Hb ≥ 120 mg/L for women and Hb≥130 mg/L for men represented no anemia.