Presence of calcified carotid plaque predicts vascular events: The Northern Manhattan Study
Introduction
The association between cardiovascular disease and vascular calcium deposition has been known since the 19th century. More recent studies have confirmed that coronary artery calcification, as detected by electron beam computed tomography (EBCT), is a marker of CAD severity and a predictor of coronary events [1], [2], [3], [4] and stroke [5]. However, studies assessing the association between carotid plaque calcification (CPC) and vascular events have produced more conflicting results [6], [7], [8], [9]. Hence, we undertook this study to prospectively determine the association between CPC, as assessed by ultrasonography, and the incidence of vascular events in a multi-ethnic stroke-free cohort. We hypothesized that presence of CPC increases the risk of vascular events.
Section snippets
Subjects and baseline evaluation
As previously described [10], the Northern Manhattan Study (NOMAS) is an ongoing prospective cohort study of stroke risk factors and outcomes. Between 1993 and 1997, 3298 subjects were enrolled who were stroke-free, >40 years of age, and residing in northern Manhattan. A carotid plaque calcification and intima-media thickness (IMT) sub-study of NOMAS began in 2000. Ultrasound data with at least one annual follow-up visit were available for 1118 NOMAS subjects.
Baseline data collection was
Results
Among 1118 subjects (mean age 68 ± 8 years; 59% women; 59% Hispanic, 22% black, 19% white), 481 (43.0%) had no plaque, 412 (36.9%) had only non-calcified plaque, and 225 (20.1%) had calcified plaque. Baseline characteristics of the cohort are shown in Table 1. Those who had calcified plaque were older, more frequently white, more likely to have completed high school, more commonly had concurrent vascular risk factors such as diabetes, hypercholesterolemia, and cardiac disease. Mean IMT was higher
Comment
We found that the presence of calcified carotid plaque was a strong and independent predictor of the combined vascular events. The association was independent of traditional cardiovascular risk factors. The effect was also independent of carotid IMT, an established strong predictor of vascular events [18]. Our results are consistent with some prior studies and support the hypothesis that arterial calcification signifies in situ plaque vulnerability and serves as a marker for generalized
Disclosures
The authors have no conflicts of interest to disclose. Each author had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Acknowledgements
Funding sources: The study was supported by grants: R01 NS 29993, T32 NS 07153.
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