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Randomized Controlled Trial
. 2011;66(8):1321-8.
doi: 10.1590/s1807-59322011000800003.

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

Monica Dias Cabral  1 , Patricia Teixeira, Debora Soares, Sandra Leite, Elizabeth Salles, Mario Waisman
Affiliations
Randomized Controlled Trial

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

Monica Dias Cabral et al. Clinics (Sao Paulo). 2011.

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.

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Figures

Figure 1
Figure 1
Changes in FMD% in the levothyroxine-treated and observation groups.
See this image and copyright information in PMC

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References

    1. Ayala A, Wartofsky L. Minimally symptomatic (subclinical) hypothyroidism. The Endocrinologist. 1997;7:44–50.
    1. Canaris GJ, Manowitz NR, Mayor G, Ridgway EC. The Colorado thyroid disease prevalence study. Arch Intern Med. 2000;160:526–34. - PubMed
    1. Cooper DS. Clinical practice. Subclinical hypothyroidism. N Engl J Med. 2001;345:260–5. - PubMed
    1. Rodondi NR, Aujesky D, Vittinghoff A, Cornus J, Bauer D. Subclinical hypothyroidism and the risk of coronary heart disease: a meta-analysis. Am J Med. 2006;119:541–51. - PubMed
    1. Ochs N, Auer R, Bauer D, Nanchen D, Gussekloo J, Cornuz J, et al. Meta-analysis: subclinical thyroid dysfunction and the risk for coronary heart disease and mortality. Ann Intern Med. 2008;148:832–45. - PubMed

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