Format

Send to:

Choose Destination
See comment in PubMed Commons below
Clinics (Sao Paulo). 2011;66(8):1321-8.

Effects of thyroxine replacement on endothelial function and carotid artery intima-media thickness in female patients with mild subclinical hypothyroidism.

Author information

  • 1Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. mdcabral@globo.com

Abstract

BACKGROUND:

Previous studies have suggested an association between subclinical hypothyroidism and coronary artery disease that could be related to changes in serum lipids or endothelial dysfunction.

METHODS:

Thirty-two female subclinical hypothyroidism patients were randomly assigned to 12 months of L-thyroxine replacement or no treatment. Endothelial function was measured by the flow-mediated vasodilatation of the brachial artery, as well as mean carotid artery intima-media thickness, and lipid profiles were studied at baseline and after 12 months of follow-up.

RESULTS:

The mean ( ± SD) serum thyroid-stimulating hormone levels in the L-thyroxine replacement and control groups were 6.09 ± 1.32 and 6.27 ± 1.39 μUI/ml, respectively. No relationship between carotid artery intima-media thickness or brachial flow-mediated vasodilatation and free T4 and serum thyroid-stimulating hormone was found. The median L-T4 dose was 44.23 ± 18.13 μg/day. After 12 months, there was a significant decrease in the flow-mediated vasodilatation in the subclinical hypothyroidism control group (before: 17.33 ± 7.88 to after: 13.1 ± 4.75%, p =0.03), but there were no significant differences in flow-mediated vasodilatation in the L-thyroxine treated group (before: 16.81 ± 7.0 to after: 18.52 ± 7.44%, p = 0.39). We did not find any significant change in mean carotid intimamedia thickness after 12 months of L-thyroxine treatment.

CONCLUSION:

Replacement therapy prevents a decline in flow-mediated vasodilatation with continuation of the subclinical hypothyroidism state. Large prospective multicenter placebo-controlled trials are necessary to investigate endothelial physiology further in subclinical hypothyroidism patients and to define the role of L-thyroxine therapy in improving endothelial function in these patients.

PMID:
21915478
[PubMed - indexed for MEDLINE]
PMCID:
PMC3161206
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Scientific Electronic Library Online Icon for PubMed Central
    Loading ...
    Write to the Help Desk