The Impact of Radiation and Its Timing on Donor Internal Mammary Vessel Histopathology at the Time of Autologous Microvascular Breast Reconstruction

Abstract Background We evaluate the impact of radiation and its early versus late effects on internal mammary vessel histomorphometry and implications for autologous breast reconstruction. Methods Patients received no radiation or radiation within the previous 6 weeks (early) or at least 6 months prior to biopsy (late) of the internal mammary vessels during free flap surgery. Clinical outcomes, and vessel measurements and markers for macrophages, smooth muscle actin (SM-ACTIN), elastin, and collagen were analyzed. Results We analyzed 36 internal mammary arteries (IMAs) and veins (IMV) in 22 patients. Six had no radiation, 12 had radiation less than 6 weeks, and 18 had radiation more than 6 months ago. Demographics, surgical variables, and cardiovascular comorbidity did not differ between groups. Macrophage counts were higher in patients who had radiation ( p