Clinical usefulness of serial measurements of carotid IMT: lessons from the IMPROVE study

AIM: In order to appraise whether serial measurements of carotid intima media thickness (C-IMT) may have some clinical value, the dataset of the “IMPROVE study” was interrogated to assess whether the C-IMT change over time 1) can be accurately measured even in single individuals, 2) can actually improve the individual cardiovascular risk stratification and c) can be actually used to assess the individual response to therapy. METHODS: A total of 3482 European subjects with at least three vascular risk factors were included into the analysis. Progression of mean and maximum C-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<0.0001), but only the Fastest-IMTmax-progr was significantly associated with the risk of VEs (P=0.0025). In reclassification analysis, the Fastest-IMTmax-prog added significant incremental prediction of VEs over and above Framingham risk factors and the initial atherosclerotic profile. In the subgroup of subjects treated with statins, the fast-progressors (subjects with a Fastest-IMTmax-prog ≥ median) have a cardiovascular risk three times greater (HR 3.18; 95% CI 1.83, 5.53) than that of slow-progressors (Fastest-IMTmax-prog < median). CONCLUSIONS: Admitted that the Fastest-IMTmax-prog is used, the assessment of change in the individual atherosclerotic profile can be of clinical usefulness.