UCLA

Background

Absence of coronary artery calcium (CAC) identifies asymptomatic individuals at low cardiovascular disease risk. Carotid artery plaque is a marker of increased risk, but its association with cardiovascular risk and incident CAC in people without CAC is unclear.

Methods

Multi-Ethnic Study of Atherosclerosis participants with CAC score of 0 at enrollment who also underwent carotid plaque measurement using B-mode ultrasonography were prospectively followed for incident coronary heart disease, stroke, and cardiovascular disease events, and CAC (score >0 on up to 3 serial computed tomography scans). The association of carotid plaque presence and plaque score (Ln[score+1]) at baseline with cardiovascular events and incident CAC was evaluated with Cox proportional hazards regression models adjusted for demographics, risk factors, and statin use.

Results

Among these 2673 participants (58 years, 64% women, 34% White, 30% Black, 24% Hispanic, and 12% Chinese), carotid plaque at baseline was observed in 973 (36%) and the median plaque score (range, 1-12) among those with plaque was 1. A total of 79 coronary heart disease, 80 stroke, and 151 cardiovascular disease events were observed during 16.1 years of follow-up. Carotid plaque presence and plaque score were independently associated with coronary heart disease risk (HRs, 1.66 [95% CI, 1.04-2.66]; and 1.48 [95% CI, 1.01-2.17], respectively) but not with stroke and cardiovascular disease risk. A total of 973 (36.4%) participants developed CAC over the evaluation period (median 9.3 years). Carotid plaque presence and plaque score were independently associated with incident CAC (HRs, 1.34 [95% CI, 1.18-1.54]; and 1.37 [95% CI, 1.21-1.54]), respectively.

Conclusions

The presence and extent of carotid plaque are associated with long-term coronary heart disease risk and incident CAC among middle-aged asymptomatic individuals with an initial CAC score of 0.