Prophylactic amifostine prevents a pathologic vascular response in a murine model of expander-based breast reconstruction.

Abstract

Although expander-based breast reconstruction is the most commonly used method of reconstruction worldwide, it continues to be plagued with complication rates as high as 60% when radiotherapy is implemented. We hypothesized that quantitative measures of radiotherapy-induced vascular injury can be mitigated by utilizing amifostine in a murine model of expander-based breast reconstruction. 30 rats were divided into three groups: expander placement (Control), expander placement followed by radiotherapy (XRT), and expander placement followed by radiotherapy with amifostine (AMF/XRT). All groups underwent placement of a sub-latissimus tissue expander. After a 45 day recovery period, all groups underwent vascular perfusion and micro-CT analysis. Micro-CT analysis was used to calculate vessel volume fraction (VVF), vessel number (VN), and vessel separation (VSp). A significant increase in VN was seen in the XRT group as compared to the Control (p = 0.021) and the AMF/XRT (p = 0.027). There was no difference between Control and AMF/XRT (p = 0.862). VVF was significantly higher in XRT than either Control (p = 0.043) and AMF/XRT (p = 0.040), however no difference was seen between Control and AMF/XRT (p = 0.980). VSp of XRT was smaller when compared to both Control and AMF/XRT specimens (p = 0.05 and p = 0.048, respectively), and no difference was seen between Control and AMF/XRT (p = 0.339). Amifostine administered prior to radiotherapy preserved vascular metrics similar to those of non-radiated specimens. Elevated vascularity demonstrated within the XRT group was not seen in either the Control or AMF/XRT groups. These results indicate that amifostine protects soft tissue in our model from a radiotherapy-induced pathologic vascular response.