Independent prognostic value of C-reactive protein and coronary artery disease extent in patients affected by unstable angina

Background: Previous studies have reported conflicting results on the association between C-reactive protein (CRP) and extent of atherosclerosis, suggesting that the association between CRP and outcome in patients with acute coronary syndromes is independent of coronary artery disease extent. We tested this hypothesis in a selected population of patients with unstable angina undergoing coronary angiography. Methods: Ninety-seven consecutive patients with unstable angina were enrolled in this single-centre study. All patients underwent coronary angiography. CRP was measured by an ultrasensitive nephelometric method. We also measured serum levels of soluble CD40 ligand by ELISA and plasma fibrinogen levels by use of the Clauss method. Atherosclerotic disease severity and extent were assessed by angiography using the Bogaty score. The extent index refers to the proportion of the coronary tree affected by detectable atheroma on angiography. The primary end-point at 6 months was a composite of: (a) death, (b) myocardial infarction, and (c) recurrence of unstable angina requiring hospitalization. Cardiac death was the secondary end-point. Results: No significant correlation was found between baseline CRP serum levels and angiographic measures of atherosclerotic disease severity and extent, whereas a trend for a significant correlation was found between soluble CD40 ligand and extent index (p=0.06). Diabetic patients exhibited a higher extent index compared to non-diabetic patients (0.94 +/- 0.1 versus 0.7 +/- 0.04, p=0.04). Predictors of primary end-point at both univariate and multivariate analysis were: extent index (p=0.04 and 0.04, respectively), CRP levels (p=0.05 and 0.02, respectively), and lack of revascularization (p=0.03 and 0.02, respectively). Fibrinogen levels were the only independent predictor of cardiac death at follow-up (p=0.04). Conclusion: In this study we demonstrate that in patients with unstable angina, CRP serum levels and coronary atherosclerosis are not correlated, but both are independently associated with a worse outcome at 6-month follow-up. (c) 2007 Elsevier Ireland Ltd. All rights reserved.