Design, Baseline Characteristics and Carotid Intima-Media Thickness Reproducibility in the PARC Study

Background: Intima-media thickness (IMT) is associated with an increased risk of cardiovascular and cerebral ischemic events, but its correlation with the absolute cardiovascular risk is not known in large populations. The Paroi Artérielle et Risque Cardiovasculaire (PARC) Study is an epidemiological study designed to correlate conventional assessment of cardiovascular risk with the mean IMT of the common carotid. Methods: In the PARC study, 6,416 subjects were enrolled, including 80.7% subjects with cardiovascular risk factors and 19.3% without. A specific methodology was designed to harmonize the acquisition and processing of data at the 283 centers. Interreader agreement on image quality and IMT measurement of the common carotid artery (CCAIMT) was assessed from a random sample of 10% of the PARC study population. Results: The intraclass correlation coefficient was 0.98 (95% CI 0.966–0.985), and the accuracy was high (standard deviation of the error measurement: 0.0185 mm). Conclusions: The reproducibility of the measurements assessed by means of the intraclass correlation coefficient and the accuracy of the CCAIMT measurement obtained in the PARC Study demonstrate the feasibility of large multicenter studies of IMT measurement.