Maor R, et al. - In this observational, prospective study of postmenopausal women with breast cancer who were enrolled at the initiation of cancer treatment, researchers investigated how peripheral endothelial function was influenced by treatment with aromatase inhibitors (AIs). A follow-up of 6–12 months was performed including all participants. Endothelial function deterioration was compared between baseline and follow-up. Also, the correlation of cardiovascular risk factors with reactive hyperemia index change in women treated with vs without AIs was also evaluated. According to findings, AIs may be related to vascular injury. Women having a higher baseline cardiovascular risk factor burden showed more pronounced impact.