Impact of prior radiotherapy and implant-based reconstruction on microvascular outcome in DIEP flap breast reconstruction

Abstract Introduction Delayed deep inferior epigastric perforator (DIEP) flap breast reconstruction may be performed after mastectomy or after a previous implant-based breast reconstruction (IBR). Fibrosis and capsule development following IBR are accentuated by radiotherapy (RT). This study aimed to evaluate whether a previous IBR is associated with increased surgical complication rates in delayed DIEP breast reconstruction in the context of RT. Method We included all patients receiving DIEP flap reconstructions at Karolinska University Hospital 2005–2022 and grouped them by RT exposure and history of IBR. Primary outcomes were intraoperative microvascular re-anastomosis and 30-day flap necrosis, which were analysed by multivariable logistic regression adjusted for age, BMI, and smoking status. Result In total, 577 DIEP flaps were performed in 516 women, 77.3% of whom had previous RT and 36.9% prior IBR. Among irradiated patients, intraoperative re-anastomosis was more common in those with prior IBR (14.7%) compared to those without (7.4%, p=0.013). Similarly, flap necrosis within 30 days was observed in 7.1% with prior IBR, versus 3.3% in those without (p=0.073). In irradiated patients, prior IBR was associated with a higher risk of intraoperative re-anastomosis (OR 1.98, 95% CI 1.04–3.76, p=0.037), while significance was not reached regarding flap necrosis (OR 2.17, CI 0.84–5.62, p=0.110). In irradiated patients, smaller venous coupler sizes were used (mean 2.03 mm vs. 2.32 mm, p=0.005), likely reflecting reduced venous elasticity. Discussion A prior IBR increased the intraoperative complexity among irradiated patients but not postoperative complications.While DIEP re-reconstruction after RT and IBR appears safe, surgeons should be aware of increased perioperative complexity.