Carotid Intima-Media Thickness Studies: Study Design and Data Analysis

Abstract

BackgroundCarotid intima-media thickness (CIMT) measurements have been widely used as primary endpoint in studies into the effects of new interventions as alternative for cardiovascular morbidity and mortality. There are no accepted standards on the use of CIMT measurements in intervention studies and choices in the design and analysis of a CIMT study are generally based on experience and expert opinion. In the present review, we provide an overview of the current evidence on several aspects in the design and analysis of a CIMT study on the early effects of new interventions.Summary of IssuesA balanced evaluation of the carotid segments, carotid walls, and image view to be used as CIMT study endpoint; the reading method (manual or semi-automated and continuously or in batch) to be employed, the required sample size, and the frequency of ultrasound examinations is provided. We also discuss the preferred methods to analyse longitudinal CIMT data and address the possible impact of, and methods to deal with missing and biologically implausible CIMT values.ConclusionsLinear mixed effects models are the preferred way to analyse CIMT data and do appropriately handle missing and biologically implausible CIMT values. Furthermore, we recommend to use extensive CIMT designs that measure CIMT at regular points during the multiple carotid sites as such approach is likely to increase the success rates of CIMT intervention studies designed to evaluate the effects of new interventions on atherosclerotic burden.

Metabolic Syndrome and Early Carotid Atherosclerosis in the Elderly

“…This study is associated with several limitations. First, there is no standardized method for measuring the C-IMT 35) , and the C-IMT methodology used in the present study could not be standardized or generalized 43) . However, baseline and follow-up sonographic tests were performed in all participants by an skillfull sonographer using the same ultrasound device and scanning methods for each participant 18) .…”

Carotid intima media thickness and blood biomarkers of atherosclerosis in patients after stroke or myocardial infarction

“…Because atherosclerosis is usually not symmetrically distributed between the left and right CCA, we used the mean CIMT from both CCAs as a single composite measure of atherosclerosis. CIMT assessment was limited to CCA, as measurements taken in the carotid bifurcation and internal carotid artery are considered less reproducible and more likely to be the source of missing data (16). …”

Carotid artery intima-media thickness and hypertensive heart disease: a short review

“…1), there have been substantial methodological differences among studies in their approach to determining cIMT. These differences include the artery examined (left, right, or both), arterial segments to be examined (common carotid, internal carotid, bifurcation), and the position of the measurements within these segments, the phase of the cardiac cycle, the walls (near or far), whether plaque is included in the measurement, ultrasound technology, image angle, and the approach to measurement (mean, max, or mean of the max; average across all segments; type of analysis software – semi-automated vs. manual) [2]. Different approaches to cIMT acquisition and measurement have been shown to vary in terms of reproducibility, predictive utility, rate of change, susceptibility to drug treatment, and the ability to obtain images for measurement [3].…”