Clinical Research
Early Atherosclerosis Detection in Asymptomatic Patients: A Comparison of Carotid Ultrasound, Coronary Artery Calcium Score, and Coronary Computed Tomography Angiography

https://doi.org/10.1016/j.cjca.2013.10.003Get rights and content

Abstract

Background

Detailed multimodality assessment of subclinical atherosclerosis in asymptomatic subjects referred for risk stratification has not been performed. We analyzed the detection of early atherosclerosis using 3 imaging modalities: coronary artery calcium (CAC) scoring, carotid ultrasound (US), and coronary computed tomography angiography (CCTA).

Methods

Asymptomatic subjects free of known vascular disease scheduled to undergo a carotid US for risk stratification were invited to undergo CCTA/CAC. Subjects taking lipid-lowering medication were excluded. All images were assessed by experienced core laboratory personnel. Carotid intima media thickness ≥ 75th percentile for age and sex, CAC > 0, and detection of either carotid or coronary artery plaque were indicators of atherosclerosis.

Results

Fifty patients were included with a median age of 53 years. Atherosclerosis was observed in 28%, 78%, and 90% of subjects using CAC, CCTA, and carotid US, respectively. All subjects showed atherosclerosis on at least 1 modality. In 36 patients with a CAC score = 0, 69% and 86% had atherosclerosis on CCTA and carotid US, respectively.

Conclusions

In this detailed analysis, all subjects identified to warrant further risk stratification had subclinical atherosclerosis on at least 1 imaging modality. Concordance between modalities was highly variable, dependent on the specific definition of atherosclerosis used. Carotid US and CCTA detection of plaque were significantly more sensitive than CAC > 0 in this middle-aged population. Considering the prevalence of subclinical disease on carotid US and CCTA, the threshold at which to treat warrants further research.

Résumé

Introduction

L’évaluation détaillée de l’imagerie multimodale de l’athérosclérose subclinique chez les sujets asymptomatiques orientés pour la stratification du risque n’a pas été réalisée. Nous avons analysé la détection de l’athérosclérose précoce en utilisant 3 modalités d’imagerie : le score calcique des artères coronaires (CAC), l’échographie (EG) carotidienne et la coronarographie par tomodensitométrie (Coro-TDM).

Méthodes

Les sujets asymptomatiques sans maladie vasculaire connue inscrits pour subir une EG carotidienne en vue de la stratification du risque ont été invités à subir la Coro-TDM/CAC. Les sujets prenant un hypolipidémiant ont été exclus. Toutes les images ont été évaluées par le personnel expérimenté du laboratoire central. L’épaisseur de l’intima-média de la carotide ≥ 75e percentile de l’âge et du sexe, le CAC > 0 et la détection de plaque carotidienne ou de plaque de l’artère coronaire ont été des indicateurs d’athérosclérose.

Résultats

Cinquante (50) patients dont l’âge moyen était de 53 ans ont été inclus. L’athérosclérose a été observée chez 28 %, 78 % et 90 % des sujets à l’aide de la CAC, la Coro-TDM et l’EG carotidienne, respectivement. Tous les sujets ont montré de l’athérosclérose dans au moins 1 modalité. Chez 36 patients ayant un score de CAC = 0,69 % et 86 % ont montré de l’athérosclérose à la Coro-TDM et l’EG carotidienne, respectivement.

Conclusions

Dans cette analyse détaillée, tous les sujets identifiés pour justifier une stratification du risque plus poussée ont montré de l’athérosclérose subclinique dans au moins 1 modalité d’imagerie. La concordance entre les modalités a été très variable, dépendamment de la définition de l’athérosclérose utilisée. La détection de la plaque à l’EG carotidienne et à la Coro-TDM a été significativement plus sensible qu’à la CAC > 0 chez cette population d’âge moyen. Si l’on considère la prévalence de la maladie subclinique à l’EG carotidienne et à la Coro-TDM, le seuil auquel traiter justifie d’autres recherches.

Section snippets

Patient enrollment

From July 2010 to August 2011, asymptomatic patients seen at a cardiovascular risk reduction clinic in a quaternary referral centre (the Healthy Heart Program Prevention Clinic, St Paul's Hospital, Vancouver, British Columbia, Canada) who were scheduled to undergo a carotid US for clinical risk stratification were invited to undergo CCTA/CAC. Only patients aged 20 years or older who provided permission to be contacted for participation in research studies were offered participation. Patients

Results

A total of 50 subjects were included in the study. Subject recruitment is summarized in Figure 1. Baseline demographic characteristics of participants are shown in Table 1. Using carotid US, the percentage of individuals with measures of early atherosclerosis varied from 28% to 90% depending on the measure used (Table 2). Only 10% of individuals had a normal carotid US (IMT < 75th percentile with no plaque present).

On CCTA, 78% of individuals were found to have atherosclerosis, defined by the

Discussion

Subclinical atherosclerosis by any definition examined in this study was widely prevalent in this referral population when detailed analysis of 2 vascular beds was performed. The correlation of atherosclerosis detection using carotid US and CCTA was only moderate at best, and a significant proportion of individuals would not have been identified if only 1 modality for atherosclerosis detection was used. A CAC score of 0 was misleading in this young population (mean age, 53 years) with high

Conclusions

Despite these limitations, the potential effect of imaging for the purpose of risk stratification and initiation of intensive treatment is demonstrated strikingly and provides provocative and clinically important insights. Concordance between the modalities was highly variable, and dependent on the specific definition used. Carotid US and CCTA detection of plaque were more sensitive than CAC > 0. Considering the strong evidence for low cardiovascular risk in patients with CAC = 0, the threshold

Funding Sources

Dr C. Taylor received funding from the Providence Health Care Boehringer Ingelheim Heart Centre Physician Scholar Award which helped to support this work.

Disclosures

Dr J. Leipsic has worked on medical advisory boards and is on the speakers bureau for GE Healthcare. All other authors have no conflicts of interest to disclose.

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