Protocol for measuring carotid intima-media thickness that best correlates with cardiovascular risk and target organ damage.

BACKGROUND: To assess which measurement of common carotid intima-media thickness (CC-IMT) is associated to a greater overall cardiovascular risk (CVR), and vascular cardiac and renal target organ damage (TOD), in diabetic, hypertensive patients and healthy subjects.
METHODS: A cross-sectional study, inclusion of 305 patients (113 hypertensive, 100 diabetics, and 92 healthy), aged 30-75 years. MEASUREMENTS: Mean CC-IMT and maximum CC-IMT in near and far walls and in the anterior, lateral and posterior projections. Ankle/brachial index (ABI), pulse wave velocity (PWV), glomerular filtration rate (GFR), albumin/creatinine ratio, Cornell voltage-duration product (VDP) and CVR with the Framingham equation and the SCORE.
RESULTS: CC-IMT shows a positive correlation with CVR, PWV, and Cornell VDP, and a negative correlation with ABI and GFR (P < 0.001), with no difference between mean and maximum values, near and far wall, or projections. The odds ratio (OR) for the presence of TOD was greatest in mean CC-IMT (OR = 1.85 (95% confidence interval (CI): 1.335-2.58)) and lowest in maximum CC-IMT in the posterior projections OR = 1.42 (95% CI: 1.12-1.80). For each unit increase in mean CC-IMT, a risk increase by 1.98 may be expected (95% CI: 0.69-3.26), whereas the risk increase for each unit increase in maximum CC-IMT is 1.75 (95% CI: 0.70-2.79) (P < 0.001) with Framingham and with no significant association with SCORE.
CONCLUSIONS: The CC-IMT measurement protocol best predicting for the occurrence of TOD and CVR estimated with Framingham is the mean of 120 measures of mean values in the near and far walls in all three projections of both carotid arteries.