The clinical significance of carotid intima-media thickness in cardiovascular diseases: a survey in Beijing

This study is to investigate the relationships between prevalent cardiovascular events (myocardial infarction, stroke and peripheral arterial disease) and carotid intima-media thickness (CIMT) in middle-aged and older adults; to assess which of the indexes, IMT in the common carotid artery (CCA), internal carotid artery (ICA) and carotid bifurcation (CB) separately or in combination, is a better correlate. IMT of the CCA, ICA and CB were measured with duplex ultrasound in 1058 individuals (aged between 37 and 86 years old) in a suburban community of Beijing. Histories of cardiovascular events as well as prevalent risk factors were obtained. CIMT were compared between groups with and without cardiovascular events. Associations of cardiovascular events with IMT measurements in CCA, CB and ICA were ascertained. The group with cardiovascular events had higher mean CIMT (0.74 (0.60–0.98) mm vs 0.65 (0.54–0.80) mm, P=0.000) and higher abnormal CIMT proportion (77.20 vs 64.45%, P=0.000). The odds ratio (OR) for myocardial infarction was 1.74 (P=0.010), for stroke 1.98 (P=0.001) and for peripheral arterial disease 1.80 (P=0.072) in abnormal CIMT. However, after adjustment of traditional risk factors, the correlations disappeared, implying that CIMT may act via other risk factors. After adjustment of age, mean CIMT correlated best with total cardiovascular events (OR: 4.39 (2.39–8.04), P=0.000) and stroke (OR: 4.98 (2.55–9.71), P=0.000) separately; mean posterior CIMT correlated with myocardial infarction best (OR: 2.97 (1.68–5.24), P=0.000). CIMT may act as an intermediate point for cardiovascular diseases. Combined CIMT might be the best index associated with cardiovascular diseases.