Impact of overnight 1 mg dexamethasone on vascular function in patients with nonfunctioning adrenal adenomas.

ABSTRACT

The purpose of this study was to evaluate the effects of administration of overnight 1 mg dexamethasone on vascular function in patients with nonfunctioning adrenal adenomas (NFA). Flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation (NID) were measured to assess vascular function in 22 patients with NFA who had hypertension and/or diabetes mellitus (DM) and 272 patients without adrenal incidentalomas who had hypertension and/or DM (control patients with hypertension and/or DM). FMD and NID were measured in the morning before and after administration of 1 mg of dexamethasone at 2300 h in 18 patients with NFA. There were no significant differences in FMD and NID between control patients with hypertension and/or DM and patients with NFA who had hypertension and/or DM (3.4 ± 2.8% vs. 2.9 ± 1.9% and 11.5 ± 5.7% vs. 11.4 ± 4.3%, P = 0.46, and P = 0.99, respectively). There were no significant differences in vascular function between control patients with hypertension and/or DM and patients with NFA who had hypertension and/or DM even after adjustment for cardiovascular risk factors. Overnight 1 mg dexamethasone increased FMD from 2.4 ± 1.9% to 5.3 ± 3.2% (P < 0.01) and increased NID from 12.1 ± 4.2% to 14.0 ± 2.8% (P < 0.01) in patients with NFA. The overnight 1 mg dexamethasone suppression test does not impair FMD and NID in patients with NFA. Decreases in circulating levels of cortisol may improve vascular function.Clinical Trial Registration This study was approved by principal authorities and ethical issues in Japan (URL for Clinical Trial http//www.umin.ac.jp/ctr/index.htm Registration Number for Clinical Trial UMIN000039512).