A proposed innovative approach to compute individual carotid intima-media thickness progression

Background: Carotid intima media thickness (IMT) progression is more inconsistently associated with vascular risk factors (VRFs) than cross-sectional measurements of carotid IMT. We propose here a new approach to compute IMT progression, which performs much better than progression variables used so far. Methods: This new approach is based on the computation of the “fastest IMT progression”, defined as the fastest IMT increase occurring in the whole carotid tree over a definite time period, regardless of its location. The dataset of the IMPROVE study (3703 subjects) was analyzed to investigate how the “fastest IMT progression” associates with a list of 28 VRFs, as compared to three conventional progression variables, i.e. progression of maximal IMT of the whole carotid tree, progression of mean IMT of the whole carotid tree, and progression of mean IMT of common carotid . Results: Using a P-value cut-off of 0.01, the “fastest IMT progression” showed a significant univariate correlation with 20 out of the 28 VRFs, the progression of maximal IMT correlated with 1 VRF, the progression of mean IMT with 8 VRFs and the progression of common carotid mean IMT with 9 VRFs. As an example, the correlation coefficients with the Framingham Risk Score were 0.11 (P<0.0001) for the “fastest IMT progression” and 0.025 (p=0.14), 0.017 (P=0.30) and 0.002 (P=0.88), for progressions of maximal IMT, mean IMT and common carotid mean IMT, respectively. Conclusions: The “fastest IMT progression” associates to VRFs much better than all the other IMT-progression variables considered, and, as such, it may represent the best target to investigate the effects of therapies aimed at VRF control.