Carotid intima-media thickness and the risk of new vascular events in patients with manifest atherosclerotic disease: the SMART study

Aims Carotid intima-media thickness (CIMT) is an independent predictor of vascular events in the general population. Currently, little is known about the relationship between CIMT and new vascular events in patients with manifest arterial disease. We aimed to assess the strength of this relationship. Methods and results The study was performed in the first consecutive 2374 patients with manifest arterial disease enrolled in the cohort study SMART (Second Manifestations of ARTerial disease), a cohort study among patients with manifest arterial disease or cardiovascular risk factors. Common CIMT was measured at baseline in both carotid arteries. Vascular events were vascular death, non-fatal myocardial infarction, or stroke, whichever occurred first. Adjusted for age and sex, an increase in common CIMT of 1 SD (similar to 0.32 mm) was associated with the occurrence of vascular events [hazard ratio (HR) 1.18; 95% confidence interval (95% CI) 1.04-1.32]. Increasing CIMT was most strongly related to ischaemic stroke incidence (HR 1.35; 95% CI 1.16-1.59). Results were similar in the 2177 patients without large common carotid plaques (CIMT < 2 mm at all measurements sites). The findings were similar after additional adjustment for risk factors of CIMT and vascular risk. Conclusion Common CIMT is associated with the occurrence of new vascular events, mostly for ischaemic stroke, in patients with manifest arterial disease. This relation does not appear to depend on the presence of plaques.