Background and Purpose--Atherosclerosis is a systemic inflammatory disease. We demonstrated previously that high-sensitivity C-reactive protein (hs-CRP) is associated with short-term progression of carotid atherosclerosis. We now investigated whether baseline levels of hs-CRP predict midterm clinical outcome in these patients.

Methods--We prospectively studied 1065 of 1268 consecutive patients who were initially asymptomatic with respect to carotid artery disease and were investigated with serial carotid ultrasound examinations at baseline and after a 6- to 9-month interval. Patients were followed-up clinically for the occurrence of cardiovascular events, a composite of myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft, stroke, and death.

Results--We recorded progression of carotid stenosis in 93 patients (9%) after 6 to 9 months, and 381 cardiovascular events in 337 patients (27%) during a median of 3 years of clinical follow-up (interquartile range, 2.5 to 3.5 years). The hs-CRP levels were significantly elevated in patients with progressive carotid stenosis (P<0.001), and hs-CRP was significantly associated with the occurrence of a first future cardiovascular event (P<0.001). Adjusted hazard ratios for a first cardiovascular event for increasing quintiles of hs-CRP were 1.41 (95% confidence interval, 0.92 to 2.17), 1.76 (95% confidence interval, 1.17 to 2.66), 2.22 (95% confidence interval, 1.48 to 3.32), and 2.41 (95% confidence interval, 1.61 to 3.60) as compared with the lowest quintile, respectively. This association was independent of traditional cardiovascular risk factors and the baseline degree of carotid stenosis.

Conclusion--Inflammation was associated with morphological and clinical progression of atherosclerotic disease. Patients with elevated levels of hs-CRP exhibit an increased risk for adverse cardiovascular outcome attributable to clinical adverse events of progressive atherosclerotic disease.