Impact of Prior Implant-Based Reconstruction and Radiotherapy on Microvascular Outcome in Deep Inferior Epigastric Perforator Flap Breast Reconstruction

BACKGROUND: Delayed deep inferior epigastric perforator (DIEP) flap breast reconstruction can be performed after either mastectomy alone or implant-based reconstruction (IBR). Fibrosis and capsular contracture after IBR are more pronounced in patients exposed to radiotherapy (RT). We evaluated whether a previous IBR increases microvascular complication rates in delayed DIEP reconstruction in patients exposed to RT. METHODS: All patients undergoing delayed DIEP reconstruction for breast cancer at a tertiary referral hospital (2005-2022) were included. Patients were categorized by history of IBR and RT. Primary outcomes were 1) perioperative microvascular re-anastomosis and 2) flap necrosis within 30 days. Logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CI) adjusted for age, body mass index, and smoking. RESULTS: In total, 516 women underwent 577 DIEP reconstructions; 213 (36.9%) had a previous IBR, 441 (77.3%) had received RT, and 170 (38.5%) had both IBR and RT. Perioperative re-anastomosis was more frequent after a previous IBR than after mastectomy alone among irradiated patients (14.7% vs. 7.4%, p=0.013). Rates of flap necrosis (partial or total) did not differ across the groups. Among irradiated patients, IBR was associated with an almost twofold increased risk of re-anastomosis compared with patients without prior IBR (OR 1.98, 95% CI 1.04-3.76). In contrast, previous IBR was not associated with flap necrosis (OR 2.17, 95% CI 0.84-5.62). Vein coupler size was smaller in irradiated than non-irradiated patients (2.03± 1.03 vs. 2.32 ± 0.89 mm, p<0.001). CONCLUSIONS: Among irradiated patients, previous IBR was associated with an increased frequency of perioperative arterial re-anastomosis but not flap loss. DIEP reconstruction remains safe in this setting, though surgeons should anticipate increased perioperative complexity.