Relation of C-reactive protein levels to presence, extent, and severity of angiographic coronary artery disease.

BACKGROUND

C-reactive protein is a valid marker of cardiovascular risk. It is not known whether C-reactive protein is a marker of atherosclerotic burden or whether it reflects a process (e.g. inflammatory fibrous cap degradation) leading to acute coronary events. This study was performed to determine whetherthe concentration of C-reactive protein is associated with coronary atherosclerosis assessed by coronary angiography.

METHODS AND RESULTS

We studied a total of 100 men and women (41 women, 59 men, mean age 63.7 +/- 11.0 years) who were referred for coronary angiography. Baseline data collection comprised clinical characteristics and conventional risk factors for coronary artery disease, levels of serum lipids and fasting total homocysteine levels. The relation between serum C-reactive protein levels and the severity and extension of coronary lesions was studied. The coronary angiograms were evaluated in a blinded manner according to three scores: vessel score (0-3 points for 0-3 vessels with coronary artery disease), stenosis score (0-3 points: number and severity of coronary stenoses or lesions; 0 for no, 1 for coronary lesion with diameter stenosis less than 50%, 2 for 50%-75%, and 3 for more than 75% diameter stenosis), and extent score (0-3 points; segment-extension of all coronary lesions within the total coronary vessel length). According to the total score values obtained, groups for coronary artery disease risk were defined and analyzed forcorrelations with age and levels of total cholesterol. high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, fasting total homocysteine. and C-reactive protein in serum. From the 100 patients, 40 were found to have no or minimal coronary artery disease (group A; score 0-3), 33 had moderate (group B; score 4-8) and 27 had severe (group C: score more than 8) coronary artery disease assessed by coronary angiography. Estimates of the relative risk of coronary heart disease for the third quintile of serum C-reactive protein as compared with the first quintile were 1.79 (95 percent confidence interval 1.23-2.39). Serum C-reactive protein levels were 3.54 (+/- 7.07) mg/L, 11.41 (+/- 13.5) mg/L and 5.66 (+/- 8.32) mg/L in groups A, B and C and represented an independent risk factor for the presence of coronary artery disease assessed by coronary angiography (p<0.01). With step-wise logistic regression analyses, use of C-reactive protein values maintained the ability to predict the probability of coronary artery disease. Moreover, the presence of angiographic coronary artery disease was associated with patient age (p=0.048), male sex (p<0.01), high LDL-cholesterol levels (p=0.02), low HDL-cholesterol levels (p=0.02), high plasma fibrinogen levels (p<0.01) and high fasting total homocysteine levels (p=0.04).

CONCLUSIONS

These results suggest that the serum concentration of C-reactive protein is associated with presence, but not severity, of coronary artery disease in patients referred for coronary angiography.