Carotid intima-media thickness at different sites: relation to incident myocardial infarction. The Rotterdam Study

Abstract

We examined whether intima-media thickness of the common carotid artery, carotid bifurcation, internal carotid artery and the combined measure are predictive of future myocardial infarction and which of the measurements has the strongest predictive value. We used a case-cohort approach in the Rotterdam Study. Ultrasound images of the common carotid artery, carotid bifurcation and the internal carotid artery were made. We selected the first 194 myocardial infarctions in the total population (mean follow-up 4.6 years). Analyses were done using Cox regression with adjustment for age and sex. The risk ratios (RR) for myocardial infarction associated with mean maximum common carotid, bifurcation, internal carotid intima-media thickness and the combined measurements were 3.18 (95% confidence interval, 1.83-5.54), 4.11 (2.10-8.05), 5.31 (1.77-15.9) and 6.27 (3.27-12.0), respectively, for the highest compared to the lowest quartile. The RRs for myocardial infarction per standard deviation increase of common carotid, bifurcation, internal carotid artery and combined intima-media thickness were 1.44 (1.28-1.62), 1.34 (1.17-1.53), 1.12 (0.94-1.33) and 1.47 (1.31-1.65), respectively. The areas under the ROC curves for the three measurements and the combined measure were not significantly different. Increased carotid intima-media thickness is a strong predictor of future myocardial infarction and all measurement sites have the same ability to predict future myocardial infarction.