Flow-mediated, endothelium-dependent vasodilation is impaired in subjects with hypothyroidism, borderline hypothyroidism, and high-normal serum thyrotropin (TSH) values.
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.
Lekakis
J
J
Department of Clinical Therapeutics, Alexandra University Hospital, Athens, Greece.
Papamichael
C
C
Alevizaki
M
M
Piperingos
G
G
Marafelia
P
P
Mantzos
J
J
Stamatelopoulos
S
S
Koutras
D A
DA
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*
D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine