Rapid changes of flow-mediated dilatation after surgical menopause.

Objectives: Estrogen acts directly on endothelial nitric oxide synthase through a non-genomic mechanism, resulting in rapid dilatation of blood vessels. In this study, we examined the change of endothelial function after surgical menopause.
Methods: In 20 subjects who underwent gynecological operations (ovariectomy (OVX) 12, sham (SHAM) operation 8), postoperative changes of flow-mediated dilatation (FMD) of the brachial artery were examined using ultrasonography. Postoperative changes of the response to nitroglycerin (NTG) were also studied in these patients.
Results: In the OVX group, significant decreases of FMD were observed 1 week after the operation, although no changes were observed in the response to NTG. In the SHAM group, no remarkable changes of FMD or the response to NTG were observed after the operation.
Conclusions: OVX influences endothelium-dependent vasodilatation within as little as 1 week. Therefore, it may be important to address the rapid changes of circulation after surgical menopause in order to prevent cardiovascular disease.