Augmentation index in resistance to thyroid hormone (RTH).
OBJECTIVE
Resistance to thyroid hormone (RTH) is associated with a varied clinical presentation. The cardiac effects of RTH have been described but vascular function has yet to be fully evaluated in this condition. We have measured the arterial function of those with RTH to assess any vascular changes.


METHODS
An observational study.


METHODS
Twelve RTH patients were recruited from the thyroid clinic (mean value +/- SD), age 40.8 +/- 18.7 years; BMI 27.2 +/- 4.2 kg/m(2) and compared with 12 healthy, euthyroid, age-matched controls (age 41.4 +/- 19.3; BMI 24.8 +/- 4.4 kg/m(2)) with no history of cardiovascular disease. No interventional measures were instituted.


METHODS
Arterial stiffness was measured using pulse wave analysis at the radial artery. Thyroid function, fasting lipids and glucose were also measured on the same occasion in both patients and controls. Results The corrected augmentation index, a surrogate marker of arterial stiffness was significantly higher in patients compared with controls (21.0% +/- 14.1%vs. 5.4% +/- 18.2%, P < 0.03). Low density lipoprotein cholesterol (LDL-cholesterol) levels were also significantly elevated in patients compared with controls (3.0 +/- 0.6 vs. 2.1 +/- 0.5 mmol/l; P < 0.002).


CONCLUSIONS
RTH patients show evidence in this study of increased augmentation index consistent with an increase in arterial stiffness compared with euthyroid controls. They also demonstrate elevated LDL-cholesterol levels. Both these measures may lead to increased cardiovascular risk.
Owen
P J D
PJ
Centre for Endocrine and Diabetes Sciences, University Hospital of Wales, Cardiff, UK. pennyowen74@yahoo.co.uk
Chatterjee
V K
VK
John
R
R
Halsall
D
D
Lazarus
J H
JH
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000453:epidemiology; D016022:Case-Control Studies; D008078:Cholesterol, LDL / Q000097:blood; D015331:Cohort Studies; D004548:Elasticity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow / Q000502:physiology*; D017534:Radial Artery / Q000503:physiopathology*; D012307:Risk Factors; D013961:Thyroid Gland / Q000503:physiopathology; D018382:Thyroid Hormone Resistance Syndrome / Q000097:blood / Q000150:complications / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D001786:Blood Glucose; D008078:Cholesterol, LDL; D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine