D31. Understanding Healing Complications in Implant-Based Breast Reconstruction using Novel Metrics in Indocyanine Green Angiography

PURPOSE: This study aims to apply a novel objective assessment of fill-rate dynamics in indocyanine green angiography ICG-A to predict wound healing complications in implant-based breast reconstruction. METHODS: This was a retrospective cohort study of intraoperative ICG recordings using the photodynamic eye (PDE) qualitative imaging system for implant-based reconstruction by two independent surgeons between April 2021-September 2023. Visual filling deficits were quantified using Image J software. Measures included time to fill, rate of change in total percentage surface area, and velocity of relative fluorescence intensity. RESULTS: 56 patients (102 breasts) were included the study. Average length of ICG recordings until a clinical decision was reached was 1.51 minutes. In 11 (19.6%) cases, a decision was made to change the reconstructive plan based upon persistent filling defects. A reduced velocity of fluorescence intensity was significantly associated with wound healing complications (17.2 units/second vs 9.9 units/second, p=.03). A final relative fluorescence intensity cutoff value of 40% demonstrated a sensitivity of 25.8% and specificity of 69.6% in detecting inadequate tissue perfusion. Perfusion deficits covering a surface area of greater than 5% were 22.6% sensitive and 89.9% specific for detecting inadequate tissue perfusion. CONCLUSION: Velocity of relative fluorescence intensity is associated with wound healing complications, but not final relative intensity. These findings suggest that ICG-A may be more specific than sensitive for detecting inadequate mastectomy flap perfusion. This study identifies novel quantitative metrics which are easily calculated, and with automation, could be made readily available intraoperatively to aid in clinical decision making.