**4.1 Comparison of preoperative baseline data between the two groups**

Among 298 patients undergoing delayed DIEP flap breast reconstruction, the overall survival rate of the flap was 99.33% (296/298). There were no significant differences between the two groups in age, BMI, history of underlying diseases, history of tumor chemotherapy, history of chest wall radiotherapy, history of abdominal surgery, history of smoking, and blood supply of the flap (uni/bi-pedicle) (*P* > 0.05) (**Table 1**).
