Lipoprotein profile and endothelial function in patients with subclinical and overt hypothyroidism.

The aim of the present study was to evaluate the lipoprotein profile and endothelial function in patients with overt hypothyroidism, SCH and euthyroid subjects and to assess the effects of these conditions on endothelial function. The TOSHIBA SSH-140-A unit was used to measure brachial artery (BA) diameter and blood flow velocity at rest and after occlusion by high pressure cuff. To induce FMD we used EDRF release test. BA was occluded by high pressure cuff for 2 minutes with pressure 50 mmHg higher then systolic blood pressure. 23 SCH (I group) women were recruited for study. We compared them with 21 patients with overt hypothyroidism (II group). The III group contained 26 euthyroidal women. The results of examination have shown that overt hypothyroid patients have significantly higher TC, LDLc and TG levels than controls, positively correlated with TSH and inversely correlated with FT4 levels. SCH patients have less marked changes, but significant positive relationships were found between serum TSH and TC and LDLc. It is important as a risk factor for cardiovascular disease. Flow-mediated, endothelium-dependent vasodilatation was significantly higher in control group (10.7+/-0.8%) compared with subjects SHT (6.5+/-0.5%) and patients with overt hypothyroidism (5.2+/-0.4%). TSH levels correlated inversely to endothelium-dependent dilatation. Thus, FMD, a marker of endothelial function, is impaired not only in patients with overt hypothyroidism, but also in subjects with SCH.