FEATURES OF CORONARY ARTERY LESIONS IN HYPOTHYROIDISM IN THE POPULATION IN SOUTH INDIA

Highlights In patients with coronary artery disease in the presence of hypothyroidism, both manifest and newly diagnosed, more pronounced dyslipidemia is observed, left ventricle diastolic dysfunction and three-vessel coronary disease are more often detected. Taking hormone replacement therapy helps reduce the severity of dyslipidemia. The number of affected coronary arteries is associated with thyroid-stimulating hormone levels. In multivariate analysis, only the presence of hypothyroidism, thyroid-stimulating hormone levels, and heart rate were independently associated with three-vessel coronary artery disease. Abstract Aim. To examine the severity of coronary artery disease (CAD) in patients with hypothyroidism and also to evaluate the factors associated with the severity of coronary atherosclerosis in the South Indian region. Methods . CAD patients (n = 240) were examined at the Kerala Institute of Medical Sciences clinic with laboratory tests (general blood count, biochemical studies, assessment of thyroid hormone levels thyroid stimulating hormone (TSH), free thyroxine (FT4)), instrumental studies – electrocardiography (ECG), echocardiography, and invasive coronary angiography. The subjects were divided into three groups: Group 1 – CAD patients without thyroid pathology (n = 150), Group 2 – CAD patients with newly diagnosed hypothyroidism without therapy (n = 15) and Group 3 (n = 75) CAD patients with hypothyroidism with hormone replacement therapy. The groups were compared according to the studied laboratory parameters and the results of instrumental examination. Results . In CAD patients with hypothyroidism, both without therapy and with therapy, statistically significant differences were revealed in the increase in the concentration of blood glucose, total cholesterol, triglycerides, low-density lipoproteins and a decrease in the content of anti-atherogenic high-density lipoprotein, compared with CAD patients without hypothyroidism (p < 0.001). In the groups of patients with hypothyroidism who had optimally selected hormone replacement therapy, as well as without therapy, the number of patients with three-vessel coronary artery disease (66.7% and 60.0%) prevailed than in the group of CAD patients without hypothyroidism (13.3%, p < 0.05). Accordingly, when assessing coronary artery disease using the SYNTAX Score, patients with hypothyroidism in both groups were more likely to have severe coronary artery lesion. In the study group, CAD patients showed statistically significant associations between TSH levels and the number of affected coronary arteries (r = 0.324, p < 0.001). In a multiple binary logistic regression model the following factors had a significant association with 3-vessel disease: group with hypothyroidism (B = 2.151; p = 0.012), free T4 level (B = 0.919; p = 0.021), and heart rate (B = 0.933; p = 0.011). Conclusions . The results of the present study highlight the need to identify hypothyroidism in patients with coronary artery disease. To correct dyslipidemia in such patients, it is necessary to additionally take hormone replacement therapy. The possibility of improving prognosis through such interventions requires confirmation in further studies.