Intraoperative Venous Congestion in DIEP Flap Reconstruction: A Pooled Analysis Demonstrating the Limited Predictive Value of Patient-Level Risk Factors

Introduction Intraoperative venous congestion complicates 2% to 20% of deep inferior epigastric perforator flap breast reconstructions (DIEP) and is attributed to persistent superficial venous dominance. Despite numerous proposed predictors, no consensus exists. This study aims to identify clinical and anatomic risk factors. Methods A retrospective cohort of DIEP patients at five university affiliated centers (2008–2021) was analyzed. Intraoperative venous congestion was defined by documentation of clinically evident congestion occurring prior to anastomosis and prompting a secondary venous outflow procedure. Preoperative CT angiograms were reviewed for anatomic variables. A rapid review identified risk factors, and cohort data were combined with extracted data to perform pooled analyses. Results Our cohort included 301 patients (411 flaps) with 36 events of intraoperative venous congestion (8.8%). Pooled data included 7189 flaps across 12 studies. Among clinical factors, diabetes (OR 1.78, 95% CI 0.89–3.59) and prior abdominal surgery (OR 1.32, 95% CI 0.67–2.63) demonstrated trends toward increased risk, while smoking, hypertension, and preoperative radiation showed no meaningful association. Anatomic factors including number of perforators and superficial inferior epigastric vein diameter were not predictive. Thinner flaps showed a trend toward congestion (mean difference −2.40 mm, 95% CI −5.24–0.54). Abnormal venous connections, reported in individual studies, showed strong associations with congestion. Conclusion Diabetes, prior abdominal surgery, and thinner flaps demonstrated trends toward association with intraoperative venous congestion, though none reached statistical significance. Abnormal venous connections, identified in the literature, showed the strongest associations and represent the highest-priority target for future investigation. Identification of these factors preoperatively may support surgical planning, but intraoperative assessment remains essential.