Background: Subclinical Cushings syndrome (SCS) due to incidentally discovered adrenal adenomas (AI) has been associated with increased prevalence of hypertension, obesity, and impaired glucose tolerance which are established risk factors for cardiovascular morbidity. Although functional and morphological (structural) changes of endothelium have been correlated with cardiovascular morbidity this has not been looked into detail in patients with adrenal incidentalomas.
Subjects and methods: Endothelial morphology and function was studied using high resolution linear array ultrasound by measurement of carotid artery intima-media-thickness (IMT) and brachial artery flow-mediated dilation (FMD) in 15 patients with SCS due to AI (54.8±2.3 years, BMI 27.9±1.07 kg/m2) (mean±S.E.M). Twenty age, gender and BMI matched patients with non functioning AI (NFAI) (53.1±2.2 years, BMI 27.3±0.6) were also studied and served as controls. Patients with SCS had incomplete inhibition of serum cortisol levels after a formal low dose 2 days 2-mg DXM suppression test. All subjects had no evidence of cardiovascular disease and/or diabetes mellitus and had normal 24 h urine catecholamine levels and no evidence of autonous aldosterone secretion. Systolic and diastolic blood pressure and the following fasting concentrations were measured: glucose, insulin, triglycerides, total cholesterol, high and low density lipoproteins, fibrinogen, homocysteine. Insulin sensitivity was assessed by the homeostasis model assessment index (HOMA).
Results: Patients with SCS had higher IMT values than patients with NFAI (0.99±0.07 mm vs 0.83±0.03, P=0.038) and lower FMD levels (3.1±0.44% vs 4.3±0.38, P=0.039) suggesting both functional and morphological endothelial dysfunction. HOMA index was significantly lower in SCS (1.94±0.34 vs 3.05±0.33 mmol/mU per l, P=0.039) reflecting a significant reduction in insulin sensitivity. No differences were found in fasting glucose levels, lipid profile and blood pressure.
Conclusion: Patients with mild subclinical autonomous cortisol excess due to AI exhibit impaired endothelial function and morphology. This could be linked to subsequently increased risk for cardiovascular diseases.
03 - 07 May 2008
European Society of Endocrinology