Coronary artery disease (CAD) remains the leading cause of morbidity and mortality worldwide, accounting for significant healthcare burden in both developed and developing countries [1,2]. Early detection and risk stratification are essential to prevent adverse cardiovascular events such as myocardial infarction and sudden cardiac death [3].

Atherosclerosis, the underlying pathology of CAD, is a systemic process characterized by the accumulation of lipid-laden plaques within arterial walls, resulting in luminal narrowing and impaired blood flow [4]. Assessment of subclinical atherosclerosis is critical for identifying individuals at high risk before the onset of symptomatic disease.

Carotid intima-media thickness (CIMT), measured by high-resolution ultrasonography, is a validated marker of subclinical atherosclerosis. It reflects structural changes in the arterial wall and correlates with cardiovascular risk factors such as age, hypertension, diabetes mellitus, and dyslipidemia [5,6]. Several studies have shown that increased CIMT is associated with a higher likelihood of coronary events and can serve as a non-invasive surrogate for systemic atherosclerosis [7,8].

CT coronary angiography (CTCA) is a non-invasive imaging modality that provides high-resolution visualization of coronary arteries, enabling the detection of luminal stenosis, plaque burden, and high-risk plaque features [9,10]. The CAD-RADS (Coronary Artery Disease Reporting and Data System) provides a standardized reporting framework for CTCA, facilitating risk stratification and guiding clinical management [11].

Although both CIMT and CTCA independently assess atherosclerotic burden, the relationship between carotid arterial thickening and coronary artery disease severity remains an area of active research. Previous studies suggest a modest correlation, with increased CIMT often associated with higher coronary plaque burden and adverse cardiovascular outcomes [12,13]. However, variability exists due to differences in patient demographics, cardiovascular risk factors, and imaging protocols.

Understanding the association between CIMT and CAD severity may aid in early identification of high-risk patients and guide preventive strategies. Therefore, this study aims to evaluate the relationship between carotid intima-media thickness and coronary artery disease severity, as assessed by CT coronary angiography, in patients presenting with chest pain.

MATERIALS AND METHODS

Study Design

This prospective observational study was conducted in the Department of Radio Diagnosis, Vydehi Institute of Medical Sciences and Research Centre (VIMS & RC), Bangalore.

Study Setting

The study was hospital-based and carried out in the Department of Radiodiagnosis, VIMS & RC, Bangalore, which receives referrals from the Departments of Cardiology and General Medicine for advanced cardiovascular imaging.

Study Population

The study included patients presenting with chest pain who were referred for radiological assessment, specifically CT Coronary Angiography (CTCA). All eligible patients underwent carotid Doppler evaluation followed by CTCA.

Inclusion Criteria

• All patients referred to the Department of Radiology for CT Coronary Angiography.

Exclusion Criteria

• Patients with cardiac arrhythmias
• Known hypersensitivity or allergy to iodinated contrast media
• Chronic kidney disease
• Pregnant or lactating women
• Hyperparathyroidism

Study Period

The duration of the study was from May 2023 to December 2024.

Sample Size Calculation

Sample size was calculated based on the sensitivity of CT Coronary Angiography reported by Ekladious et al., where sensitivity was 92.9%. Using the formula:

Where

• = 1.96 (95% confidence interval)
• = 92.9%
• = 10% relative precision (9.29)

Considering a 10% dropout rate, the final sample size was estimated at 33 patients.

Method of Evaluation

All eligible patients referred for CTCA were first subjected to carotid artery Doppler ultrasonography to measure carotid intima-media thickness (CIMT). In the absence of contraindications, oral Ivabradine (10 mg) was administered for heart-rate control prior to CTCA.

CT Coronary Angiography

CTCA was performed using a 128-slice Siemens SOMATOM Definition AS Multi-Detector CT scanner. Heart rate reduction to <60 bpm was targeted for optimal image acquisition.

Patient Preparation

• Fasting for 4–6 hours
• Adequate hydration (unless contraindicated)
• Heart rate control using Ivabradine
• Renal function assessment (creatinine/eGFR)

Contrast Protocol

• Non-ionic iodinated contrast (e.g., Iohexol)
• Injection rate: 4–6 mL/s
• Contrast volume: 50–100 mL
• Saline flush: 30–50 mL
• Bolus tracking with ROI at ascending aorta

ECG Gating

• Prospective gating for stable heart rates
• Retrospective gating for arrhythmias

Scan Parameters

• Tube voltage: 100–120 kV
• Tube current: 200–800 mA
• Slice thickness: 0.5–0.75 mm
• Reconstruction interval: 0.25–0.5 mm
• FOV: Coronary arteries, aortic root, pulmonary artery

Image Interpretation

CTCA findings were interpreted using the CAD-RADS (Coronary Artery Disease Reporting and Data System) classification. High-risk plaque features assessed included spotty calcifications, positive remodelling, low-attenuation plaque (<30 HU), and the napkin-ring sign.

Patients were also evaluated for the Agatston calcium score.

Carotid Doppler Ultrasonography

Carotid Doppler was performed using a Samsung V6 ultrasound system with a 5–12 MHz linear transducer.

Procedure

• Patient positioned supine with neck slightly extended.
• B-mode imaging for structural assessment (CCA, ICA, ECA, bifurcation).
• Colour and spectral Doppler for flow characterisation.
• CIMT measured at the far wall of the distal common carotid artery.

Interpretation

CIMT values were categorised as:

• Normal:<0.75 mm
• Intermediate: 0.75–1.0 mm
• High risk:>1.0 mm
  CIMT >1.5 mm was considered plaque.

Ethical Considerations

The study adhered to the guidelines of the Indian Council of Medical Research (ICMR, 1994) and the Declaration of Helsinki (2000 revision).

• Written informed consent was obtained from all participants.
• Privacy and confidentiality were strictly maintained.
• Patients were allowed to withdraw at any point without prejudice.
• The study posed minimal risk, with all precautions taken to ensure patient safety.

The study was approved by the Institutional Ethics Committee.

Statistical Analysis

Data were entered in Microsoft Excel and analyzed using SPSS version 21.0.

• Descriptive statistics: mean, standard deviation, percentages, and proportions.
• Comparative analysis: appropriate parametric or non-parametric tests applied based on data distribution.
  A p-value <0.05 was considered statistically significant.

RESULTS AND OBSERVATIONS

Table 1: Age Distribution of Study Participants

Graph 1: CIMT Distribution graph, showing the variation in CIMT values among patients.

Graph 2: Bar chart representing the CAD-RADS Score Distribution

Table 2: Distribution of Calcium Scores Among Study Participants

Graph 3: Regression plot of CAD-RADS Score vs.

Table 3: Carotid Intima-Media Thickness (CIMT) by Age Group

Table 4: Age vs. CAD-RADS Score

Table 5: Summary of Key Parameters and Variability in Study Population

DISCUSSION

This study evaluated the relationship between carotid intima-media thickness (CIMT) and coronary artery disease (CAD) severity in patients undergoing CT coronary angiography (CTCA). A total of 33 patients were included, with a wide age range (22–72 years) and a mean age of 45.8 ± 12.56 years. The study population predominantly included middle-aged individuals (40–50 years, 36.4%), consistent with the age range commonly affected by early atherosclerotic changes [1,2].

CIMT and Age

CIMT increased progressively with age, from a mean of 0.45 mm in patients <30 years to 0.92 mm in those >70 years (Table 3). This finding aligns with previous studies showing that carotid arterial walls thicken with age due to endothelial dysfunction, smooth muscle proliferation, and cumulative exposure to cardiovascular risk factors [3,4]. The 40–50 years age group showed higher variability in CIMT, suggesting that some individuals develop early atherosclerotic changes while others remain relatively healthy. Monitoring CIMT in middle-aged and older adults may aid in early risk stratification for cardiovascular disease [5].

CAD-RADS Scores and Age

Analysis of CAD-RADS scores (Table 4) indicated no strong linear correlation between age and CAD severity. While older patients tended to have higher CAD-RADS scores, some younger individuals also exhibited moderate-to-severe CAD. These observations support the multifactorial nature of CAD, influenced by genetic predisposition, lifestyle factors, and comorbidities such as diabetes mellitus and hypertension [6,7]. This underscores the need to evaluate CAD risk beyond chronological age alone.

CIMT and CAD Severity

Although CIMT is a surrogate marker for systemic atherosclerosis, the study observed no strong direct correlation between CIMT and CAD-RADS scores. Patients with moderate CIMT often had low calcium scores, and only a few outliers had both high CIMT and high calcium scores (Table 5). This finding suggests that arterial wall thickening does not always correspond with extensive coronary plaque burden, reflecting the heterogeneity of atherosclerotic progression [8,9]. Similar observations have been reported in prior studies, where CIMT correlated modestly with coronary plaque burden but did not consistently predict high-risk coronary lesions [10,11].

Calcium Scores

The calcium score distribution indicated that most patients had low scores (0–50, 75.8%), while only a few had significantly elevated scores (>100), consistent with the right-skewed distribution observed in prior epidemiological studies (Table 2) [12]. High calcium scores in a small subset of patients reflected advanced calcified plaque, which is strongly associated with increased cardiovascular risk [13]. The combination of CIMT and calcium score may better identify high-risk individuals than either measure alone.

Clinical Implications

The results suggest that CIMT measurement can serve as a useful screening tool to detect subclinical atherosclerosis, particularly in middle-aged patients. However, its predictive value for CAD severity is limited, and CTCA remains the gold standard for anatomical assessment of coronary arteries. Integrating CIMT evaluation with calcium scoring and CAD-RADS classification can provide a more comprehensive assessment of cardiovascular risk [14,15].

Limitations

Although this study offers valuable insights into the connection between CIMT and CAD, it also has several limitations. First, the study is cross-sectional, meaning it captures data at a single point in time, preventing assessment of long-term disease progression or causal relationships. Second, while CIMT was found to correlate with CAD severity, other important cardiovascular risk factors—such as lipid levels, inflammatory markers, genetic predisposition, and lifestyle factors (diet, smoking, and physical activity)—were not included in the analysis. Future studies should focus on overcoming these limitations by including longitudinal data, larger sample sizes, metabolic markers, and clinical outcomes, thereby improving the predictive value of CIMT in assessing CAD risk.

CONCLUSION

CIMT increases with age and reflects subclinical atherosclerosis, but does not strongly correlate with CAD severity on CT coronary angiography. Most patients had low calcium scores, while a few with both high CIMT and elevated calcium scores were at higher cardiovascular risk. Combined assessment of CIMT, calcium scoring, and CAD-RADS can improve cardiovascular risk stratification and guide early preventive interventions.

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