Elsevier

Atherosclerosis

Volume 206, Issue 2, October 2009, Pages 451-457
Atherosclerosis

Association of traditional cardiovascular risk factors with coronary plaque sub-types assessed by 64-slice computed tomography angiography in a large cohort of asymptomatic subjects

https://doi.org/10.1016/j.atherosclerosis.2009.05.027Get rights and content

Abstract

Objective

Although prior studies have shown that traditional cardiovascular (CV) risk factors are associated with the burden of coronary atherosclerosis, less is known about the relationship of risk factors with coronary plaque sub-types. Coronary computed tomography angiography (CCTA) allows an assessment of both, total disease burden and plaque characteristics. In this study, we investigate the relationship between traditional CV risk factors and the presence and extent of coronary plaque sub-types in a large group of asymptomatic individuals.

Methods

The study population consisted of 1015 asymptomatic Korean subjects (53 ± 10 years; 64% were males) free of known CV disease who underwent 64-slice CCTA as part of a health screening evaluation. We analyzed plaque characteristics on a per-segment basis according to the modified American Heart Association classification. Plaques in which calcified tissue occupied more than 50% of the plaque area were classified as calcified (CAP), <50% calcified area as mixed (MCAP), and plaques without any calcium as non-calcified (NCAP).

Results

A total of 215 (21%) subjects had coronary plaque while 800 (79%) had no identifiable disease. Multivariate regression analysis demonstrated that increased age (per decade) and gender are the strongest predictors for the presence of any coronary plaque or the presence of at least one segment of CAP and MCAP (any plaque—age: OR 2.89; 95% CI 2.34, 3.56; male gender: OR 5.21; 95% CI 3.20, 8.49; CAP—age: OR 2.75; 95% CI 2.12, 3.58; male gender: 4.78; 95% CI 2.48, 9.23; MCAP—age: OR 2.62; 95% CI 2.02, 3.39; male gender: OR 4.15; 95% CI 2.17, 7.94). The strongest predictors for the presence of any NCAP were gender (OR 3.56; 95% CI 1.96–6.55) and diabetes mellitus (OR 2.87; 95% CI 1.63–5.08). When looking at the multivariate association between the presence of ≥2 coronary segments with a plaque sub-type and CV risk factors, male gender was the strongest predictor for CAP (OR 7.31; 95% CI 2.12, 25.20) and MCAP (OR 5.54; 95% CI 1.84, 16.68). Alternatively, smoking was the strongest predictor for the presence of ≥2 coronary segments with NCAP (OR 4.86; 95% CI 1.68, 14.07). Low-density lipoprotein cholesterol (LDL-C) was only a predictor for the presence and extent of mixed coronary plaque.

Conclusion

Age and gender are overall the strongest predictors of atherosclerosis as assessed by CCTA in this large asymptomatic Korean population and these two risk factors are not particularly associated with a specific coronary plaque sub-type. Smoking is a strong predictor of NCAP, which has been suggested by previous reports as a more vulnerable lesion. Whether a specific plaque sub-type is associated with a worse prognosis is yet to be determined by future prospective studies.

Introduction

Traditional cardiovascular risk stratification tools tend to underestimate cardiovascular event risk, especially in women and in young individuals [1], [2]. Given that a significant number of individuals who experience a first myocardial infarction (MI) did not have chest pain or any clinical evidence of coronary artery disease (CAD) prior to the event, early disease detection becomes an important element of cardiovascular prevention efforts [3].

Quantification of coronary arterial calcification (CAC) provides prognostic information beyond identification of traditional CV risk factors [4], [5]. Although the CAC score correlates well with disease burden, calcified plaques (CAP) only represent a portion of the total atherosclerosis plaque burden [6]. The residual atherosclerotic burden is composed of pure non-calcified (NCAP) coronary plaques or mixed (MCAP) with some calcified component. Previous reports have suggested that coronary NCAPs are associated, more so than CAPs, with acute coronary syndrome [7], [8]. In addition, MCAPs have been associated with the presence of severe perfusion defects by single-photon emission computed tomography [9].

The use of 64-slice coronary computed tomography angiography (CCTA) has been validated as a sensitive and specific tool not only for the detection of significant coronary stenosis [10], [11], [12], [13] but also for defining plaque morphology and plaque outward expansion [14], [15], factors that could potentially play a role in the degree of plaque vulnerability. There is a paucity of data regarding the association of plaque morphology, or plaque sub-type, with the presence of traditional CV risk factors. The purpose of this study is to investigate this association in a large cohort of asymptomatic subjects without a history of CAD.

Section snippets

Study population

We did a retrospective sub-analysis of 1074 consecutive South Korean individuals who underwent CCTA evaluation using 64-slice multidetector computed tomography (MDCT) as part of a general routine health evaluation in the Seoul National University Bundang Hospital (SNUBH) between December 2005 and May 2006. An initial cross-sectional evaluation of this subject population has been published elsewhere [16]. For the present analysis, we excluded 59 subjects who had chest pain or discomfort prior to

Characteristics of study population

Our cohort consisted of 1015 asymptomatic South Korean individuals who had no history of CAD. The study population characteristics are outlined in Table 1. The mean age was 53 ± 10 years and 64% were males. Mean lipid parameters were within normal limits (LDL-C 117 ± 32 mg/dl, HDL-C 60 ± 13 mg/dl, and triglycerides 133 ± 89 mg/dl). A significant percent (34%) of study participants were smokers and 20% were hypertensive. Overall, the cohort had a low risk for the development of future cardiovascular events.

Discussion

To the best of our knowledge, this is the first study that reports on the association of traditional CV risk factors with coronary plaque sub-types, using 64-slice CCTA, in a large cohort of exclusively asymptomatic individuals without a history of CAD. The main findings are the following: (1) age and male gender were overall the strongest predictors for the presence of CAP and MCAP; they were also the strongest predictors for the presence of ≥2 coronary segments with CAP and MCAP; (2) male

Conclusions

Age and gender are overall the strongest predictors of atherosclerosis and are not exclusively associated with the presence of any of the different plaque sub-types. Smoking is strongly associated with the extent of coronary NCAPs, a type of plaque which has been associated with vulnerability and acute events. These findings should be corroborated on other ethnic groups. Although the use of CCTA for the characterization of plaque morphology is promising and could potentially lead to future risk

References (27)

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