Correlation of Carotid Intima-media Thickness with Cardiovascular Dysfunction in Known Hypothyroid Patients: A Cross-sectional Study from a Tertiary Care Hospital in Kolkata, India

Introduction: Hypothyroidism is linked to adverse changes in lipid metabolism and cardiac function, increasing cardiovascular risk. The major cardiovascular changes that occur in hypothyroidism include a decrease in cardiac output and cardiac contractility, a reduction in heart rate, and an increase in peripheral vascular resistance. Carotid intima-media Thickness (CIMT) is an established marker of subclinical atherosclerosis. Aim: To evaluate the correlation between CIMT and cardiovascular parameters in patients with hypothyroidism. Materials and Methods: The present cross-sectional observational study was conducted at the Medical College and Hospital, Kolkata, West Bengal, India (General Medicine Department, Inpatients and Outpatients) between December 2022 and May 2024. A total of 100 patients with established primary hypothyroidism were enrolled. Data collected included demographics (age, sex), Body Mass Index (BMI) and Blood Pressure (BP), thyroid function tests {Thyroid-Stimulating Hormone (TSH), Free Thyroxine (FT4), anti-Thyroid Peroxidase (anti-TPO) antibody}, lipid profile, liver and renal function tests, fasting glucose and HbA1c, Complete Blood Count (CBC), 12- lead ECG, Two-dimensional Echocardiography (2D ECHO), and carotid Doppler ultrasound to measure CIMT and carotid artery flow velocities. Statistical analyses (Pearson’s correlation, Chi-square test and Student’s t-test) were performed using appropriate software, with p<0.05 considered significant. Results: Of the 100 patients, 54% were female. Most (82%) had overt hypothyroidism and 18% had subclinical hypothyroidism. Mean±SD body mass index was 26.2±2.8 kg/m², and mean diastolic blood pressure was 89.4±3.0 mmHg. Mean±SD total cholesterol was 197±33 mg/dL, triglycerides 188±71 mg/dL, low-density lipoprotein cholesterol 116±95 mg/dL, and highdensity lipoprotein cholesterol 46.93±4.9365 mg/dL. Sinus bradycardia was present in 43%, and diastolic dysfunction (grade I–II) on echocardiography was observed in 42% of patients. The mean common carotid artery intima-media thickness (CCA-CIMT) was 0.62±0.13 mm (right) and 0.60±0.14 mm (left). The corresponding mean internal carotid artery CIMT (ICA-CIMT) values were 0.60±0.14 mm (right) and 0.62±0.14 mm (left). Crucially, CIMT showed significant positive correlations with total cholesterol (r=0.72, p<0.001), triglycerides (r=0.69, p<0.001), LDL-cholesterol (r=0.20, p=0.05), peak systolic velocities in the right and left common carotid arteries (p<0.001 for both), and TSH (r=0.25, p=0.01), and a significant negative correlation with HDL-cholesterol (r=-0.26, p=0.008). Conclusion: In patients with hypothyroidism, CIMT is positively correlated with atherogenic lipid parameters and TSH. These findings suggest that increased CIMT reflects subclinical atherosclerotic and cardiovascular risk in hypothyroid patients and underlines the importance of early cardiovascular evaluation in this population.