Normal flow-mediated vasodilatation of the brachial artery and carotid artery intima-media thickness in subclinical hypothyroidism

Subclinical hypothyroidism (SHT) is a disease for which exact therapeutic approaches have not yet been established. Previous studies have suggested an association between SHT and coronary heart disease. Whether this association is related to SHT-induced changes in serum lipid levels or to endothelial dysfunction is unclear. The aim of this study was to determine endothelial function measured by the flow-mediated vasodilatation of the brachial artery and the carotid artery intima-media thickness (IMT) in a group of women with SHT compared with euthyroid subjects. Triglycerides, total cholesterol, HDL-C, LDL-C, apoprotein A (apo A), apo B, and lipoprotein(a) were also determined. Twenty-one patients with SHT (mean age: 42.4 ± 10.8 years and mean thyroid-stimulating hormone (TSH) levels: 8.2 ± 2.7 µIU/mL) and 21 euthyroid controls matched for body mass index, age and atherosclerotic risk factors (mean age: 44.2 ± 8.5 years and mean TSH levels: 1.4 ± 0.6 µIU/mL) participated in the study. Lipid parameters (except HDL-C and apo A, which were lower) and IMT values were higher in the common carotid and carotid bifurcation of SHT patients with positive serum thyroid peroxidase antibodies (TPO-Ab) (0.62 ± 0.2 and 0.62 ± 0.16 mm for the common carotid and carotid bifurcation, respectively) when compared with the negative TPO-Ab group (0.55 ± 0.24 and 0.58 ± 0.13 mm, for common carotid and carotid bifurcation, respectively). The difference was not statistically significant. We conclude that minimal thyroid dysfunction had no adverse effects on endothelial function in the population studied. Further investigation is warranted to assess whether subclinical hypothyroidism, with and without TPO-Ab-positive serology, has any effect on endothelial function.

Prevalence of peripheral arterial disease by ankle-brachial index and its correlation with carotid intimal thickness and coronary risk factors in Nepalese population over the age of forty years.

OBJECTIVES: Noninvasive measures of subclinical atherosclerosis such as the ankle brachial index (ABI) and common carotid artery intima-media thickness (CCA IMT) could improve risk prediction and provide more focused primary prevention strategies. This report describes the prevalence of subclinical atherosclerotic vascular disease in a Nepalese population over the age of forty years as measured by ABI and CCA IMT and their association with established cardiovascular risk factors. MATERIALS AND METHODS: Ultrasonic evaluation of ABI and CCA IMT was done in 195 individuals of age 40 years and above who had presented to an outpatient department. Patients with established diagnosis of coronary artery disease or symptomatic for peripheral arterial disease were excluded from the study. RESULTS: The prevalence of atherosclerotic disease as measured by ABI was 18.5% and there was a statistically significant correlation between ABI and CCA IMT and other established cardiovascular risk factors such as smoking, diabetes mellitus and hypertension. CONCLUSIONS: We recommend that ABI as measured by sphygmomanometer be incorporated into routine cardiovascular screening and when found to be abnormal further confirmed by Doppler assessment of ABI and CCA IMT as surrogate markers of atherosclerotic vascular disease.

Impact of Multiple Cardiovascular Risk Factors on the Carotid Intima-media Thickness in Young Adults: The Kangwha Study / 예방의학회지

OBJECTIVES: Although risk factors for coronary artery disease are also associated with increased carotid intima-media thickness (IMT), there is little information available on the asymptomatic, young adult population. We examined the association between multiple cardiovascular risk factors and the common carotid IMT in 280 young Korean adults. METHODS: The data used for this study was obtained from 280 subjects (130 men and 150 women) aged 25 years who participated in the Kangwha Study follow-up examination in 2005. We measured cardiovascular risk factors, including anthropometrics, blood pressure, blood chemistry, carotid ultrasonography, and reviewed questionnaires on health behaviors. Risk factors were defined as values above the sex-specific 75th percentile of systolic blood pressure, body mass index, total cholesterol/high-density lipoprotein cholesterol ratio, fasting blood glucose and smoking status. RESULTS: The mean carotid IMT+/-standard deviation observed was 0.683+/-0.079 mm in men and 0.678+/-0.067 mm in women (p=0.567) and the evidence of plaque was not observed in any individuals. Mean carotid IMT increased with an increasing number of risk factors(p for trend <0.001) and carotid IMT values were 0.665 mm, 0.674 mm, 0.686 mm, 0.702 mm, and 0.748 mm for 0, 1, 2, 3, and 4 to 5 risk factors, respectively. The odds ratio for having the top quartile carotid IMT in men with 3 or more risk factors versus 0-2 risk factors was 5.09 (95% CI, 2.05-12.64). CONCLUSIONS: Current findings indicate the need for prevention and control of cardiovascular risk factors in young adults and more focus on those with multiple cardiovascular risk factors.

Carotid intima-media thickness as an independent predictor of coronary artery disease.

BACKGROUND: A noninvasive technique of measuring carotid artery intima-media thickness has recently generated considerable interest as a marker of atherosclerosis and in the prediction of clinical coronary events and coronary artery disease. The present study evaluated the association of carotid artery intima-media thickness in the prediction of coronary artery disease in a western Indian population. METHODS AND RESULTS: Carotid artery intima-media thickness was measured with a B-mode scan in an ongoing study of 266 patients, who were further subdivided into 4 subgroups: those with non-insulin dependent diabetes mellitus; hypertension; diabetes mellitus with hypertension; and those without diabetes or hypertension (labeled as controls). The maximal intima-media thickness greater than 0.8 mm at the far wall of the common carotid artery, excluding raised lesions and plaques, was selected as the highest value for comparison. The subgroups were further divided into those with and without apparent coronary artery disease. A statistically significant intima-media thickness greater than 0.8 mm was observed in 59.2% of the subjects with coronary artery disease as against 40.8% in those without the disease on univariate analysis. A higher incidence of intima-media thickness of more than 0.8 mm was observed in all subgroups with coronary artery disease as against those without the disease, which was most marked in the hypertensive group (22.2% v. 3.6%) and contributed to the increased arterial thickness in diabetics with concomitant hypertension. Multivariate regression analysis revealed carotid artery intima-media thickness to be associated with coronary artery disease with an odds ratio of 2.40. CONCLUSIONS: Carotid artery intima-media thickness is a simple, noninvasive and reproducible clinical tool to evaluate atherosclerosis and predict coronary artery disease in Indian subjects. Prospective studies in a larger number of subjects, particularly in those undergoing coronary angiography, will help in establishing the role of this technique.