Effect of obesity on coronary artery plaque using 64 slice multidetector cardiac computed tomography angiography

Non-calcified plaque in asymptomatic patients with zero coronary artery calcium score: A systematic review and meta-analysis

BACKGROUND

There is growing interest in understanding the coronary atherosclerotic burden in asymptomatic patients with zero coronary artery calcium score (CACS). In this population, we aimed to investigate the prevalence and severity of non-calcified coronary plaques (NCP) as detected by coronary CT angiography (CCTA), and to analyze the associated clinical predictors.

METHODS

This was a systematic review with meta-analysis of studies indexed in PubMed/Medline and Web of Science from inception of the database to March 31st, 2023. Using the random-effects model, separate Forest and Galbraith plots were generated for each effect size assessed. Heterogeneity was assessed using the I2 statistics whilst Funnel plots and Egger's test were used to assess for publication bias.

RESULTS

From a total of 14 studies comprising 37808 patients, we approximated the pooled summary estimates for the overall prevalence of NCP to be 10% (95%CI: 6%-13%). Similarly, the pooled prevalence of obstructive NCP was estimated at 1.1% (95%CI: 0.7%-1.5%) from a total of 10 studies involving 21531 patients. Hypertension [OR: 1.46 (95%CI:1.31-1.62)] and diabetes mellitus [OR: 1.69 (95%CI: 1.41-1.97)] were significantly associated with developing any NCP, with male gender being the strongest predictor [OR: 3.22 (95%CI: 2.17-4.27)].

CONCLUSION

There is a low burden of NCP among asymptomatic subjects with zero CACS. In a subset of this population who have clinical predictors of NCP, the addition of CCTA has a potential to provide a better insight about occult coronary atherosclerosis, however, a risk-benefit approach must be factored in prior to CCTA use given the low prevalence of NCP.

Radiation Doses in Patients Undergoing Computed Tomographic Coronary Artery Calcium Evaluation With a 64-Slice Scanner Versus a 256-Slice Scanner

Computed tomographic coronary artery calcium scanning enables cardiovascular risk stratification; however, exposing patients to high radiation levels is an ongoing concern. New-generation computed tomographic systems use lower radiation doses than older systems do. To quantify comparative doses of radiation exposure, we prospectively acquired images from 220 patients with use of a 64-slice GE LightSpeed VCT scanner (control group, n=110) and a 256-slice GE Revolution scanner (study group, n=110). The groups were matched for age, sex, and body mass index; statistical analysis included t tests and linear regression. The mean dose-length product was 21% lower in the study group than in the control group (60.2 ± 27 vs 75.9 ± 22.6 mGy·cm; P <0.001) and also in each body mass index subgroup. Similarly, the mean effective radiation dose was 21% lower in the study group (0.84 ± 0.38 vs 1.06 ± 0.32 mSv) and lower in each weight subgroup. After adjustment for sex, women in the study group had a lower dose-length product (50.4 ± 23.4 vs 64.7 ± 27.6 mGy·cm) than men did and received a lower effective dose (0.7 ± 0.32 vs 0.9 ± 0.38 mSv) (P=0.009). As body mass index and waist circumference increased, so did doses for both scanners. Our study group was exposed to radiation doses lower than the previously determined standard of 1 mSv, even after adjustment for body mass index and waist circumference. In 256-slice scanning for coronary artery calcium, radiation doses are now similar to those in lung cancer screening and mammography.

Pericardial fat volume and coronary atherosclerotic markers among body mass index groups

Background

Increased pericardial fat volume (PFV) is associated with coronary atherosclerosis burden independent of body mass index (BMI) in many clinical studies. However, the association of PFV with markers of coronary atherosclerosis has not yet been assessed by dividing the patients according to BMI categories.

Hypothesis

To assess the association of PFV measured by multi‐detector CT (MDCT) angiography with coronary atherosclerotic markers (coronary artery calcium score [CAC], plaque type, and luminal stenosis) among BMI categories.

Methods

A total of 496 patients with suspected coronary artery disease who underwent 64‐slice MDCT angiography examination were enrolled. Patients divided into obese, overweight, and normal weight groups according to BMI degree.

Results

PFV showed a significant association with CAC, non‐calcified coronary plaque, and significant coronary stenosis in obese group. After adjusting for cardiac risk factors, the association of PFV with the non‐calcified coronary plaque and significant coronary stenosis persisted. There was a significant association between PFV with CAC and significant coronary stenosis in normal weight group. The association between PFV with CAC and significant coronary stenosis in normal weight was persisted afar adjusting for cardiac risk factors. No significant association was noted between PFV with coronary plaque type in normal weight group. There was no significant independent association between PFV with coronary atherosclerotic markers in overweight group.

Conclusions

Increased PFV was associated with advanced stage atherosclerosis in normal weight group, while increased PFV was associated with non‐calcified plaque in obese. These results highlight the differential relationship of PFV with coronary atherosclerotic markers among BMI categories.

Correlation between epicardial adipose tissue and severity of coronary artery stenosis evaluated by 64-MDCT

PURPOSE

The purpose was to investigate the correlation between epicardial adipose tissue (EAT) thickness, EAT volume, and severity of coronary artery stenosis.

METHODS

We retrospectively enrolled 188 patients that underwent coronary computed tomography (CT) angiography for clinically suspected coronary artery disease using 64-MDCT. Images were reconstructed using a retrospective electrocardiogram-gated algorithm with 0.625-mm-thick sections. EAT thickness and volume were calculated.

RESULTS

The coronary CT angiography showed 106 patients who had coronary artery pathology (178 lesions), 21 patients with moderate stenosis (27 lesions), 12 patients with severe stenosis (18 lesions), and 6 patients with complete occlusion (8 lesions). EAT thickness, EAT volume, and Gensini score were statistically different among groups (FT=32.306, FV=27.743, F=110.483, P=.000). Pearson correlation analysis showed that Gensini score had significantly positive correlation with EAT thickness and volume, respectively.

CONCLUSION

EAT thickness and volume demonstrated a positive correlation with severity of coronary artery stenosis.

Beyond Coronary Stenosis: Coronary Computed Tomographic Angiography for the Assessment of Atherosclerotic Plaque Burden

Coronary computed tomographic angiography (CCTA) is emerging as a key non-invasive method for assessing cardiovascular risk by measurement of coronary stenosis and coronary artery calcium (CAC). New advancements in CCTA technology have led to the ability to directly identify and quantify the so-called "vulnerable" plaques that have features of positive remodeling and low density components. In addition, CCTA presents a new opportunity for noninvasive measurement of total coronary plaque burden that has not previously been available. The use of CCTA needs also to be balanced by its risks and, in particular, the associated radiation exposure. We review current uses of CCTA, CCTA's ability to measure plaque quantity and characteristics, and new developments in risk stratification and CCTA technology. CCTA represents a quickly developing field that will play a growing role in the non-invasive management of cardiovascular disease.

Semiquantified noncalcified coronary plaque in systemic lupus erythematosus

OBJECTIVE

A major cause of morbidity and mortality in systemic lupus erythematosus (SLE) is accelerated coronary atherosclerosis. New technology (computed tomographic angiography) can measure noncalcified coronary plaque (NCP), which is more prone to rupture. We report on a study of semiquantified NCP in SLE.

METHODS

Patients with SLE (n = 147) with no history of cardiovascular disease underwent 64-slice coronary multidetector computed tomography (MDCT). The MDCT scans were evaluated quantitatively by a radiologist, using dedicated software.

RESULTS

The group of 147 patients with SLE was 86% female, 70% white, 29% African American, and 3% other ethnicity. The mean age was 51 years. In our univariate analysis, the major traditional cardiovascular risk factors associated with noncalcified plaque were age (p = 0.007), obesity (p = 0.03; measured as body mass index), homocysteine (p = 0.05), and hypertension (p = 0.04). Anticardiolipin (p = 0.026; but not lupus anticoagulant) and anti-dsDNA (p = 0.03) were associated with higher noncalcified plaque. Prednisone and hydroxychloroquine therapy had no effect, but methotrexate (MTX) use was associated with higher noncalcified plaque (p = 0.0001). In the best multivariate model, age, current MTX use, and history of anti-dsDNA remained significant.

CONCLUSION

Our results suggest that serologic SLE (anti-dsDNA) and traditional cardiovascular risk factors contribute to semiquantified noncalcified plaque in SLE. The association with MTX is not understood, but should be replicated in larger studies and in multiple centers.

Significance of noncalcified coronary plaque in asymptomatic subjects with low coronary artery calcium score: assessment with coronary computed tomography angiography

We aimed to investigate the prevalence and severity of noncalcified coronary plaques (NCP) using coronary CT angiography (CCTA) and analyze predictors of significant coronary stenosis by NCP in asymptomatic subjects with low coronary artery calcium score (CACS). The institutional review board approved this retrospective study and all patients gave written, informed consent. The presence of plaque, severity of stenosis, plaque characteristics, and CACS were assessed in 7,515 asymptomatic subjects. We evaluated the prevalence and severity of NCP in subjects having low CACS (707 subjects; men with CACS from 1 to 50 and women from 1 to 10) in comparison to those having 0 CACS (6,040 subjects) as the reference standard. Conventional risk factors were assessed for predictors of NCP and significant stenosis by NCP. We also investigated the cardiac events of the patients through medical records. Compared to subjects with 0 CACS, those with low CACS showed higher prevalence of NCP (6.9% vs. 31.5%, P < 0.001) and significant stenosis caused by NCP (0.8% vs. 7.5%, P < 0.001). In the low CACS group, independent predictors for significant NCP included diabetes mellitus (DM), hypertension, and elevated low-density lipoprotein (LDL)-cholesterol (all P < 0.05). However, 47.2% of subjects with significant NCP were classified into the low to intermediate risk according to Framingham Risk Score. At the median follow up of 42 months (range: 3-60 months), cardiac events were significantly higher in the low CACS group compared to the 0 CACS group (2.6% vs. 0.27%, P < 0.001). In asymptomatic subjects having low CACS, the prevalence and severity of NCP were higher as compared to subjects having zero CACS and predictors of significant stenosis by NCP were DM, hypertension and LDL-Cholesterol. Therefore, CCTA may be useful for risk stratification of coronary artery disease as added value over CACS in selected populations with low CACS who have predictors of significant NCP.

Prevalence and predictors of atherosclerosis in symptomatic patients with zero calcium score

RATIONALE AND OBJECTIVES

Absence of coronary artery calcium (CAC) in symptomatic patients is associated with a very low risk of adverse cardiovascular events. However, patients with zero CAC may have noncalcified plaques (NCP). In this analysis, we sought to determine the prevalence and predictors of NCP in symptomatic patients with zero CAC.

MATERIALS AND METHODS

Coronary computed tomography angiography (CCTA) was performed in 333 consecutive symptomatic patients (mean age 50 ± 12, 65% males) with zero CAC and no known coronary artery disease (CAD). Pretest likelihood was estimated by Framingham risk score (FRS). Independent predictors of NCP were identified using multivariate logistic regression.

RESULTS

NCP was detected in 55 patients (17%) on CCTA, of which 6 patients (1.8%) had significant stenosis. In univariate analysis, patients with NCP were older (55 ± 7 vs. 50 ± 10 years, P = .009), with higher prevalence of hypertension (80% vs. 63%, P = .013). Using multivariate logistic regression, the independent predictors of NCP in this cohort were intermediate to high FRS (OR 2.3, 95%CI 1.3-4.1, P = .007), whereas baseline statin therapy was associated with lower prevalence of NCP (OR 0.38, 95%CI 0.17-0.89, P = .02).

CONCLUSION

Our analysis shows that nearly one in five patients with zero calcium score has NCP and one in three patients with zero calcium score and intermediate to high FRS have evidence of NCP on CCTA. The prognostic value of NCP in these patients needs further evaluation.