European Journal of Cardiovascular Medicine

Coronary artery disease (CAD) remains the leading cause of morbidity and mortality worldwide, with diabetes mellitus (DM) being a major independent risk factor that accelerates the process of atherosclerosis and increases the likelihood of multi-vessel disease [1]. The prevalence of CAD in diabetic patients is significantly higher compared to non-diabetic individuals, with diabetic patients often presenting with more diffuse, calcified, and clinically silent lesions, leading to delayed diagnosis and worse outcomes [2].

Advancements in non-invasive imaging, particularly multi-detector computed tomography coronary angiography (CTCA), have revolutionized the assessment of CAD by enabling direct visualization of coronary lumen and plaque morphology. Among these technologies, the 128-slice CT scanner offers superior temporal and spatial resolution, allowing accurate assessment of coronary stenosis and plaque characterization while also enabling coronary artery calcium scoring (CACS) for risk stratification [3].

CACS, measured using the Agatston score, is a well-established predictor of future cardiovascular events, with higher scores correlating with greater atherosclerotic burden. Diabetic patients generally demonstrate higher CACS compared to non-diabetic individuals, reflecting more extensive calcific plaque deposition [4]. However, a high calcium burden can reduce CTCA accuracy in detecting significant stenosis due to blooming artifacts, underscoring the importance of evaluating both functional and anatomical data together [5].

Given these considerations, evaluating the role of 128-slice CTCA and CACS in differentiating the extent and severity of CAD between diabetic and non-diabetic subject. Hence this study was conducted and the primary objective of this study was to evaluate the coronary arteries using 128-slice multidetector computed tomography (MDCT) by CT coronary angiography and calcium scoring for the detection of coronary artery disease (CAD) in diabetic and non-diabetic subjects, and to assess the incidence and severity of CAD and calcium scores in males and females across different age groups. Secondary objectives included comparing coronary artery calcium scores between subjects with and without hypertension and smoking history, and evaluating differences in calcium scores between patients with single-vessel and multi-vessel disease.

This cross-sectional study was conducted at Bharat Education and Research Foundation, Chennai, after obtaining institutional ethics committee approval. A total of 100 patients (both genders) with and without diabetes mellitus (DM) who underwent CT coronary angiography were included. DM was diagnosed using fasting, postprandial, and random blood sugar levels. Patients with acute coronary syndromes, chronic kidney disease, uncontrolled tachycardia, or technically inadequate CT scans were excluded.

Clinical Evaluation: Detailed history was obtained for all participants, including cardiovascular risk factors (DM, hypertension, smoking, family history of CAD). Baseline investigations included complete blood count, blood sugar profile, renal function tests, and electrocardiogram.

CT Coronary Angiography Protocol: All scans were performed on a 128-slice multidetector CT scanner (Ultra low dose, GE, Chennai). Patients refrained from caffeine prior to the procedure. Oral metoprolol (50 mg) was administered when necessary to maintain optimal heart rate. Calcium scoring was performed first using prospective ECG gating, followed by coronary angiography with 80 mL of 350 mg/mL iodinated contrast injected at 4 mL/s, and a saline flush. Acquisition parameters included collimation 0.625 × 16 mm, pitch 0.3–1, rotation time 0.5 s, 120 kV, and 360 mA. Images were obtained during breath-hold, preferably in the late R–R interval.

Calcium Scoring and Image Analysis: Calcium scoring was performed on a GE Smart Score workstation using the Agatston method, with manual region-of-interest selection to exclude non-coronary calcifications. Scores were calculated per vessel and summed for the total calcium score, classified as: 0 (no calcification), 1–100 (mild), 101–400 (moderate), and >400 (severe). Any score >0 was considered positive.

Significant stenosis was defined as ≥50% luminal narrowing, assessed visually and quantitatively using multiplanar reconstructions, maximum intensity projections, and 3D volume rendering. The left anterior descending, left circumflex, and right coronary arteries, and major branches were evaluated. Patients were classified as: normal (no stenosis), single-vessel involvement, or multivessel involvement (>1 vessel with significant stenosis).

Additional Cardiac Assessment: Cardiac chambers were assessed for morphological abnormalities, hypertrophy, aneurysms, and septal defects. Left ventricular output and stroke volume were measured using Cardiac Q Express software.

Statistical Analysis: Data were analyzed using chi-square test, multiple linear regression, and ANOVA. p ≤ 0.01 was considered significant at the 1% level, p ≤ 0.05 at the 5% level, and p > 0.05 as not significant. Coronary calcium scores and vessel involvement were compared between diabetic and non-diabetic patients, as well as subgroups with and without hypertension and smoking history.

The study included 100 patients, comprising 53 diabetics and 47 non-diabetics. Most participants (67%) were aged over 60 years, while 16% were aged between 40 and 60 years, and 17% were under 40 years. The majority were male (91%), with only 9% female. Hypertension was present in 25% of the cohort, smoking in 30%, and a family history of CAD in 29% (Table 1).

Analysis of vessel involvement revealed significant associations with age, diabetes, hypertension, smoking, and family history of CAD (all p < 0.001), while gender was not significantly related (p = 0.3575). Older age groups, particularly those aged ≥60 years, demonstrated higher rates of multivessel disease. Diabetic patients had markedly greater multivessel involvement (82.8%) compared to non-diabetics (17.2%), and hypertensive patients had more extensive disease (75.9%) compared to non-hypertensives (24.1%). Similarly, smokers and those with a positive family history exhibited higher rates of multivessel involvement than their counterparts (Table 2).

When stratified by total coronary artery calcium (CAC) score, age, diabetes, hypertension, smoking, and family history were all significantly associated with higher calcium scores (all p < 0.05), while gender showed no significant relationship (p = 0.575). Severe calcification was most common in older age groups, particularly ≥60 years, and among diabetics (87% with severe CAC) compared to non-diabetics (13%). Hypertension and smoking were also linked to more severe CAC. Notably, vessel involvement increased with rising CAC scores; patients with severe calcification had the highest prevalence of multivessel disease (82.6%), whereas those with normal scores had no multivessel disease (Table 3).

Further analysis confirmed that both diabetes and hypertension were significantly associated with multivessel involvement. Among diabetics, 24 patients had multivessel disease compared to only five non-diabetics (p < 0.001). Similarly, 22 hypertensive patients had multivessel involvement compared to seven non-hypertensives (p < 0.001) (Table 4). These findings highlight the strong predictive value of diabetes and hypertension for extensive coronary artery disease.

Table 1: Profile of subjects

Table 2: Factors associated with Vessel Involvement

Table 3: Factors associated with Total Calcium Scoring

Table 4: Association between Multi vessel Involvement and DM and HTN

Table 5: Multiple linear Regression Analysis to determine the association between the diabetes, hypertension, smoking, family history of CAD with total vessel involvement

The Value of R (correlation) = 0.480 indicates that there is a moderate level of prediction. The R² (coefficient of determination) = 0.231 explains that our independent variables explain 23.1% variability of our dependent variable "total vessel involvement".

Estimated model coefficients:

The general form of the equation to predict Total Vessel Involvement from Diabetes, Hypertension, smoking and Family history of CAD is:

Predicted Total vessel Involvement = 1.104 + 0.591 (Diabetes) + 0.603 (Hypertension) + 0.329 (Smoking) + 0.175 (Family History of CAD)

A multiple regression was run to predict Total Vessel involvement from Diabetes, Hypertension, smoking and Family history of CAD. These variables statistically significantly predicted total Vessel Involvement, F (4, 95) = 19.407, p < 0.0001, R = 0.480, R² = 0.231. All three variables added statistically significantly to the prediction, p < 0.05 excluding Family history of CAD.

Table 6: Multiple linear Regression Analysis to determine the association between the diabetes, hypertension, smoking, family history of CAD with Total Calcium Score

Statistical Significance: The Value of R (correlation) = 0.480 indicates that there is a moderate level of prediction. The R² (coefficient of determination) = 0.231 explains that our independent variables explain 23.1% variability of our dependent variable "total calcium score". The F-ratio in the ANOVA table tests whether the overall regression model is a good fit for the data. The table shows that the independent variables statistically significantly predict the dependent variable, F (4, 95) = 7.127, p < 0.0001 (i.e., the regression model is a good fit of the data).

Estimated model coefficients: The general form of the equation to predict Total calcium scoring from Diabetes, Hypertension, smoking and Family history of CAD is:

Predicted Total calcium scoring = -102.389 + 316.816 (Diabetes) + 464.520 (Hypertension) + 259.244 (Smoking) - 5.949 (Family History of CAD)

A multiple regression was run to predict Total calcium scoring from Diabetes, Hypertension, smoking and Family history of CAD. These variables statistically significantly predicted total Vessel Involvement, F (4, 95) = 7.127, p < 0.0001, R² = 0.231. All three variables added statistically significantly to the prediction, p < .05 excluding Family history of CAD.

Table 7: Multiple linear Regression Analysis to determine the association between the diabetes, hypertension with total vessel involvement

The Value of R (correlation) = 0.634 indicates that there is a good level of prediction. The R² (coefficient of determination) = 0.402 explains that our independent variables explain 40.2% variability of our dependent variable total vessel involvement.

Statistical Significance:  The F-ratio in the ANOVA table tests whether the overall regression model is a good fit for the data. The table shows that the independent variables statistically significantly predict the dependent variable, F (2, 97) = 32.563, p < 0.0001 (i.e., the regression model is a good fit of the data).

Estimated model coefficients:

The general form of the equation to predict vessel involvement from Diabetes and Hypertension is

Predicted Total vessel involvement = 1.165 + 0.656 (Diabetes) + 0.730 (Hypertension)

A multiple regression was run to predict total vessel involvement from Diabetes and Hypertension. These variables statistically significantly predicted total Vessel Involvement, F (2, 97) = 32.563, p < 0.0001, R² = 0.634. All two variables are statistically significantly to the prediction, p < 0.05.

Table 8: Multiple linear Regression Analysis to determine the association between the diabetes, hypertension with Total Calcium Score

The Value of R (correlation) = 0.456 indicates that there is a moderate level of prediction. The R² (coefficient of determination) = 0.208 explains that our independent variables explain 20.8% variability of our dependent variable total calcium scoring.

Statistical Significance:  The F-ratio in the ANOVA table tests whether the overall regression model is a good fit for the data. The table shows that the independent variables statistically significantly predict the dependent variable, F (2, 97) = 12.735, p < 0.0001 (i.e., the regression model is a good fit of the data).

Estimated model coefficients:

The general form of the equation to predict Total Calcium scoring from Diabetes and Hypertension is

Predicted Total calcium scoring = -6.066 + 332.873 (Diabetes) + 526.936 (Hypertension)

A multiple regression was run to predict total calcium scoring from Diabetes and Hypertension. These variables statistically significantly predicted total Vessel Involvement, F (2, 97) = 12.735, p < 0.0001, R² = 0.208. All two variables are statistically significantly to the prediction, p < 0.05.

In our study, there was a significant association between diabetes, hypertension, smoking, and family history of CAD—both individually and in combination—with total vessel involvement. Conversely, sex showed no significant relationship with total vessel involvement. Diabetes mellitus combined with hypertension also demonstrated a significant correlation with multivessel disease.

Similarly, diabetes, hypertension, smoking, and family history of CAD were significantly associated with total calcium scores, while sex was not. Diabetes and hypertension, individually and combined, showed strong associations with both higher calcium scores and multivessel involvement. The left anterior descending artery was the most frequently involved vessel.

In our cohort, 68% of patients were aged >50 years, and the incidence of CAD increased significantly with age. Older age was also associated with greater arterial calcification and higher total calcium scores. This aligns with findings from Idris et al. and the Rotterdam Study, which demonstrated that age is an independent risk factor for CAD and that CAC retains its prognostic value in the elderly [6]. In our analysis, age and total calcium score had a significant correlation (p = 0.0001).

Gender differences in CAD prevalence are well documented, with women generally developing clinical disease later than men. In our study, there were 70 males and 30 females; single-vessel involvement was found in 24.3% of men and 23.3% of women, while multivessel disease was present in 32.9% and 20%, respectively. No significant correlation was observed between gender and vessel involvement, nor between gender and total calcium score (p = 0.5751). Previous research has shown mixed results, with some studies reporting lower CAC prevalence in women [7], [8], while others found ethnic variations in CAC burden [7].

Diabetes is a well-established risk factor for both increased CAC and more extensive CAD. In our study, among 53 diabetic patients, 17% had mild, 15.1% moderate, and 37.7% severe calcium scores, with a significant association between diabetes and total calcium score (p = 0.0003). Furthermore, 45.3% of diabetics had multivessel involvement compared to 10.6% of non-diabetics (p < 0.001). These findings are consistent with earlier work demonstrating that diabetics with CAC have higher event rates than non-diabetics, and that absence of CAC in diabetics is associated with outcomes similar to CAC-negative non-diabetics [9].

Hypertension was present in 42% of our study population and was significantly associated with both multivessel involvement (p < 0.001) and higher CAC (p < 0.0001). These results align with Zeina et al. and Valenti et al., who reported higher prevalence and prognostic value of CAC in hypertensive individuals [10].

Although smoking is a well-recognized CAD risk factor, its association with CAC is less consistent. In our study, smoking was significantly correlated with both total vessel involvement and total calcium score. This agrees with global data indicating smoking’s strong contribution to cardiovascular mortality [11].

A positive family history was present in 29% of patients, with 51.7% having multivessel disease. There was a significant correlation between family history and both total vessel involvement (p = 0.0001) and total calcium score (p = 0.0002). Our findings mirror those of Pandey et al., who showed family history independently predicts CAC development and progression [12].

We observed a strong relationship between calcium score severity and extent of vessel disease. Severe CAC was associated with a high prevalence of multivessel involvement (p < 0.0001). This is consistent with Gökdeniz et al., who demonstrated that CAC correlates with CAD complexity and mortality risk [12].

When analyzed together, diabetes, hypertension, smoking, and family history of CAD were significantly associated with both total vessel involvement and total calcium score in multivariate analysis. Similar patterns were observed in the Euro-CCAD study, which identified these risk factors as strong predictors of significant coronary stenosis and increased CAC burden [12].

Incidental non-coronary findings, such as aortic and pulmonary vessel calcifications, were detected in a few cases, highlighting the additional diagnostic yield of CAC scanning beyond CAD assessment.

The present study has certain limitations that should be acknowledged. First, the number of female participants was relatively small, which may limit the generalizability of gender-related findings. Second, invasive coronary angiography—the gold standard for assessing coronary plaque burden—was not performed, precluding direct comparison of CT findings with angiographic data. Third, patients with renal disease were excluded due to the risks associated with contrast administration, thereby limiting the applicability of the results to this subgroup. Fourth, the study did not include long-term follow-up to evaluate the prognostic implications of CAC scores. Additionally, CAC scoring was not performed in patients with acute coronary syndrome or chronic stable angina. Finally, in cases of extensive calcification, accurate assessment of luminal diameter was challenging, which may have influenced stenosis interpretation.

In our study, there was a significant association between diabetes, hypertension, smoking, and family history of CAD—both individually and in combination—with total vessel involvement. Conversely, sex showed no significant relationship with total vessel involvement. Diabetes mellitus combined with hypertension also demonstrated a significant correlation with multivessel disease.

Similarly, diabetes, hypertension, smoking, and family history of CAD were significantly associated with total calcium scores, while sex was not. Diabetes and hypertension, individually and combined, showed strong associations with both higher calcium scores and multivessel involvement. The left anterior descending artery was the most frequently involved vessel.

In our cohort, 68% of patients were aged >50 years, and the incidence of CAD increased significantly with age. Older age was also associated with greater arterial calcification and higher total calcium scores. This aligns with findings from Idris et al. and the Rotterdam Study, which demonstrated that age is an independent risk factor for CAD and that CAC retains its prognostic value in the elderly [6]. In our analysis, age and total calcium score had a significant correlation (p = 0.0001).

Gender differences in CAD prevalence are well documented, with women generally developing clinical disease later than men. In our study, there were 70 males and 30 females; single-vessel involvement was found in 24.3% of men and 23.3% of women, while multivessel disease was present in 32.9% and 20%, respectively. No significant correlation was observed between gender and vessel involvement, nor between gender and total calcium score (p = 0.5751). Previous research has shown mixed results, with some studies reporting lower CAC prevalence in women [7], [8], while others found ethnic variations in CAC burden [7].

Diabetes is a well-established risk factor for both increased CAC and more extensive CAD. In our study, among 53 diabetic patients, 17% had mild, 15.1% moderate, and 37.7% severe calcium scores, with a significant association between diabetes and total calcium score (p = 0.0003). Furthermore, 45.3% of diabetics had multivessel involvement compared to 10.6% of non-diabetics (p < 0.001). These findings are consistent with earlier work demonstrating that diabetics with CAC have higher event rates than non-diabetics, and that absence of CAC in diabetics is associated with outcomes similar to CAC-negative non-diabetics [9].

Hypertension was present in 42% of our study population and was significantly associated with both multivessel involvement (p < 0.001) and higher CAC (p < 0.0001). These results align with Zeina et al. and Valenti et al., who reported higher prevalence and prognostic value of CAC in hypertensive individuals [10].

Although smoking is a well-recognized CAD risk factor, its association with CAC is less consistent. In our study, smoking was significantly correlated with both total vessel involvement and total calcium score. This agrees with global data indicating smoking’s strong contribution to cardiovascular mortality [11].

A positive family history was present in 29% of patients, with 51.7% having multivessel disease. There was a significant correlation between family history and both total vessel involvement (p = 0.0001) and total calcium score (p = 0.0002). Our findings mirror those of Pandey et al., who showed family history independently predicts CAC development and progression [12].

We observed a strong relationship between calcium score severity and extent of vessel disease. Severe CAC was associated with a high prevalence of multivessel involvement (p < 0.0001). This is consistent with Gökdeniz et al., who demonstrated that CAC correlates with CAD complexity and mortality risk [12].

When analyzed together, diabetes, hypertension, smoking, and family history of CAD were significantly associated with both total vessel involvement and total calcium score in multivariate analysis. Similar patterns were observed in the Euro-CCAD study, which identified these risk factors as strong predictors of significant coronary stenosis and increased CAC burden [12].

Incidental non-coronary findings, such as aortic and pulmonary vessel calcifications, were detected in a few cases, highlighting the additional diagnostic yield of CAC scanning beyond CAD assessment.

The present study has certain limitations that should be acknowledged. First, the number of female participants was relatively small, which may limit the generalizability of gender-related findings. Second, invasive coronary angiography—the gold standard for assessing coronary plaque burden—was not performed, precluding direct comparison of CT findings with angiographic data. Third, patients with renal disease were excluded due to the risks associated with contrast administration, thereby limiting the applicability of the results to this subgroup. Fourth, the study did not include long-term follow-up to evaluate the prognostic implications of CAC scores. Additionally, CAC scoring was not performed in patients with acute coronary syndrome or chronic stable angina. Finally, in cases of extensive calcification, accurate assessment of luminal diameter was challenging, which may have influenced stenosis interpretation.

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