title: Flow-mediated, endothelium-dependent vasodilation is impaired in subjects with hypothyroidism, borderline hypothyroidism, and high-normal serum thyrotropin (TSH) values.
abstract: Patients with hypothyroidism are considered to have an increased risk of developing atherosclerosis; because endothelial dysfunction is an early sign of atherosclerosis, we investigated whether endothelial dysfunction is present in patients with hypothyroidism. Thirty-five subjects with various TSH levels were investigated by high-resolution ultrasound imaging of the brachial artery to assess endothelial and smooth muscle responses. Flow-mediated, endothelium-dependent vasodilatation was significantly higher in subjects with TSH 0.4-2 microIU/mL (11.8 +/- 2.7%), compared with subjects with TSH 2.01-4 microIU/mL (6.8 +/- 2.9%), 4.01-10 microIU/mL (5.2 +/- 6.3%) and >10 microIU/mL (4.0 +/- 4.4%); TSH levels correlated inversely to endothelium-dependent dilatation. Thus, flow-mediated vasodilatation, a marker of endothelial function, is impaired not only in patients with mild hypothyroidism but also in subjects with "high-normal" serum TSH levels (ie, 2.01-4.0 microIU/mL) that may be characterized as possibly abnormal.
authors.affiliation: Department of Clinical Therapeutics, Alexandra University Hospital, Athens, Greece.
authors.forename: J
authors.initials: J
authors.lastname: Lekakis
authors.forename: C
authors.initials: C
authors.lastname: Papamichael
authors.forename: M
authors.initials: M
authors.lastname: Alevizaki
authors.forename: G
authors.initials: G
authors.lastname: Piperingos
authors.forename: P
authors.initials: P
authors.lastname: Marafelia
authors.forename: J
authors.initials: J
authors.lastname: Mantzos
authors.forename: S
authors.initials: S
authors.lastname: Stamatelopoulos
authors.forename: D A
authors.initials: DA
authors.lastname: Koutras
mesh_terms: D000328:Adult; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000502:physiology*; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D012044:Regression Analysis; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014463:Ultrasonography; D014664:Vasodilation / Q000502:physiology*
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine