Myocardial perfusion and intima-media thickness in patients with subclinical hypothyroidism

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ABSTRACT

Purpose

The data concerning the relation between subclinical hypothyroidism (SH) and the risk of cardiovascular disease are divergent. We aimed to assess myocardial perfusion in contrast-enhanced echocardiography and intima-media thickness (IMT) in patients with SH.

Material/Methods

Forty females with SH without symptoms of coronary artery disease and 15 healthy female volunteers were examined. Echocardiographic evaluation of the left ventricle function as well as carotid and femoral IMT complex measurements were performed at baseline. Thereafter, dobutamine stress echocardiography with myocardial perfusion assessment at rest and on the peak of stress test was performed. SonoVue® intravenous bolus as a contrast medium was used. The myocardial perfusion was assessed by quantitative method using Q-LAB Philips software (ROI modality). The perfusion index was calculated (a number of left ventricle segments with improved perfusion/a number of all segments).

Results

A mean IMT value in the SH group was significantly higher than in the controls (0.7 mm vs. 0.38 mm, p=0.001). Myocardial perfusion at rest and at the peak of stress test was significantly lower in the SH patients as compared to the controls (at rest 120 Db in SH vs. 181 Db in controls, p=0.039 and at the peak of stress 115 Db and 188 Db, p=0.01, respectively). The perfusion index was not significantly worse in the SH group (p=0.6). IMT values negatively correlated with the myocardial perfusion index at the peak of stress (r=−0.54, p=0.014).

Conclusions

In patients with SH contrast-enhanced echocardiographic examination revealed myocardial hypoperfusion and increased IMT. Our results may suggest that the patients with SH are at risk of the development of cardiovascular disease.

Section snippets

INTRODUCTION

Subclinical hypothyreosis (SH) is featured by elevated concentration in plasma TSH concomitant with normal concentration in plasma free thyroxine (fT4). The literature data indicate clearly that patients with SH have increased incidence of coronary heart disease (CHD) and increased risk of death as a consequence of cardiovascular complications [1]. It was shown that SH is also accompanied by increased plasma concentration of LDL-cholesterol and increased incidence of arteriosclerotic plaques in

MATERIAL AND METHODS

The experimental protocol was approved by the Ethical Committee for Human Studies of the Medical University of Bialystok. The subjects gave written consents for the study. 40 women, aged 34.8±4.1 years with diagnosed SH in the course of Hashimoto disease were included. The diagnosis of SH was confirmed by elevation in TSH concentration coexisting with normal concentration of fT4, the presence of antibodies against thyroid peroxidase (aTPO) and hypogenic (typical) picture of ultrasonographic

RESULTS

The characteristics of the investigated subjects is presented in the Tab. 1. The patients with SH had elevated concentration in the plasma total cholesterol and LDL-cholesterol as compared to the control group (p<0.03 and 0.006, respectively). The subjects with SH were not obese but their BMI was higher than in the control group (p<0.03).

DISCUSSION

A relationship between thyroid disorders and the condition of the vascular bed is not thoroughly recognized. SH occurs quite often. According to the Third National Health and Nutrition Examination Survey, it occurs in 4.3% of adults in the United States of America and the incidence of its prevalence increases with ageing. It concerns ∼10% of women above the age of sixty [5]. There are a few theories trying to explain the mechanism of the influence of SH on the cardiovascular system. According

CONCLUSIONS

In patients with SH, echocardiographic stress test with the use of ultrasonographic contrast is safe and seems to be helpful to detect the reduction of myocardial perfusion at the level of microcirculation. The results obtained clearly show that in patients with SH increased thickness of IMT which is an early and sensitive parameter indicating the degree of atherosclerosis and allowing a selection of patients much threatened with cardiovascular disorders. Both employed echocardiographic methods

ACKNOWLEDGMENTS

This work was supported by Medical University of Bialystok (Poland) grant: 3-53726L. The authors thank Professor Maria Gorska, the Head of the Department of Endocrinology for help in the requirement of the study patients.

REFERENCES (22)

  • G Lervasi et al.

    Association between increased mortality and mild thyroid dysfunction in cardiac patients

    Arch Intern Med

    (2007 Jul 23)
    • View full text
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