Evaluation of Carotid Intima-Media Thickness and Resistive Index in Hypertensive and Normotensive Patients Using B-Mode and Colour Doppler Sonography: A Comparative Study with Biochemical Parameters

Abstract

Background: Hypertension is a major cardiovascular risk factor that leads to structural and functional changes in the arterial wall, increasing the risk of atherosclerosis, stroke, and coronary artery disease. Carotid intima-media thickness (CIMT) and carotid resistive index (RI), measured using B-mode and Colour Doppler ultrasonography, are reliable non-invasive markers of early vascular damage. This study aimed to compare CIMT and RI between hypertensive and normotensive individuals and evaluate their association with biochemical parameters. Materials and Methods: This hospital-based observational case-control study was conducted in the Department of Radiodiagnosis and Imaging at Muzaffarnagar Medical College, Muzaffarnagar, Uttar Pradesh, over 18 months. A total of 60 participants were enrolled, including 30 patients with essential hypertension and 30 normotensive controls. All participants underwent bilateral carotid artery evaluation using B-mode and Colour Doppler ultrasonography to measure carotid intima-media thickness and resistive index. Biochemical parameters, including fasting blood sugar, total cholesterol, and serum triglycerides, were also recorded. Continuous variables were expressed as mean ± standard deviation, and a p-value <0.05 was considered statistically significant. Results: Hypertensive patients had significantly higher systolic and diastolic blood pressure than normotensive controls (p<0.001). The mean carotid intima-media thickness was significantly greater in hypertensive patients (1.18 ± 0.07 mm) than in controls (0.75 ± 0.03 mm) (p<0.001). Similarly, the mean carotid resistive index was significantly higher in the hypertensive group (0.737 ± 0.024) compared with controls (0.626 ± 0.013) (p<0.001). Mean CIMT showed a strong positive correlation with systolic blood pressure (r=0.835, p<0.001), while RI correlated positively with the duration of hypertension (r=0.689, p<0.001). CIMT also demonstrated significant positive correlations with total cholesterol and triglycerides. Conclusion: Patients with essential hypertension exhibit significantly increased carotid intima-media thickness and resistive index compared with normotensive individuals, indicating early structural and functional vascular remodelling. B-mode and Colour Doppler ultrasonography provide a simple, safe, and non-invasive method for the early detection of subclinical vascular changes. Combined assessment of carotid ultrasonographic parameters and biochemical markers may improve cardiovascular risk stratification and facilitate early therapeutic intervention.

Keywords: Essential hypertension; Carotid intima-media thickness; Resistive index; B-mode ultrasonography; Colour Doppler sonography; Atherosclerosis; Cardiovascular risk.