Clinical usefulness of carotid IMT progression: lessons from the improve study

BACKGROUND: The clinical usefulness of serial measurements of carotid artery intima media thickness (C-IMT) remains controversial. Uncertainties include: a) whether it is possible to accurately assess the IMT change in single individuals, b) whether the measurement of IMT change over time actually improves the physician capacity to stratify the individual cardiovascular risk and c) whether change of C-IMT over time can actually help the physician in a better assessment of the individual response to a therapy. To address these issues we have reanalyzed the dataset of the IMPROVE project, a European, multicenter, longitudinal, observational study specifically designed to assess whether the 15-month carotid IMT progression associate with vascular events (VEs) occurring during the subsequent 21.8 months of follow-up. METHODS: A total of 3703 European subjects with at least three vascular risk factors were included into the study. Progression of mean and maximum IMT of the left and right common carotids, bifurcations, internal carotid arteries and of the whole carotid tree as well as the fastest IMT-progression detected in the whole carotid tree, regardless of its location, were included in Cox proportional hazards models as predictors of vascular events and in reclassification analyses. RESULTS: All IMTs significantly progressed during 15 months (all P