Objective To explore the association of CRP levels with the severity of coronary stenosis in patients with coronary artery disease (CAD) documented by angiography.

Methods A total of 368 patients with angiographically determined CAD (defined as stenosis of >= 50% in 1 or more coronary arteries) were enrolled after exclusion of patients with acute myocardial infarction, acute infectious diseases or CRP >=10 mg/l, and chronic liver or kidney diseases. Serum CRP was measured using particle enhanced immunoturbidimetric method (DiaSys, Germany). CAD severity was assessed by the number of stenotic coronary arteries and the Gensini score. In the current study, LDL-C <130 mg/dl was defined as the lower level of LDL-C and LDL-C 3130 mg/dl as the higher level of LDL-C.

Results Of 368 patients, 179 patients had single-vessel stenosis, 105 had 2 stenotic vessels, and 84 had ≥3 stenotic vessels. Systolic blood pressure and triglycerides levels increased significantly with the number of stenotic arteries. Median and inter-quartile range (IQR) of CRP in patients with single-vessel stenosis and multi-vessel stenosis was 0.93 (0.44–2.41) mg/l and 1.33 (0.66–2.39) mg/l, respectively, p=0.030. Univariate analysis found that participants with CRP ≥1 mg/l had a significantly higher Gensini score (29.0 (12.0–56.0) vs 20.0 (10.0–46.2), p=0.026) and higher prevalence of multi-vessel stenosis (57.6% vs 44.1%, p=0.010) than those with CRP <1 mg/l. After age, gender, body mass index, systolic blood pressure, smoking status, fasting glucose, HDL-C and LDL-C adjustments, CRP levels remained to be associated with CAD severity. The OR was 1.77 (95% CI 1.14 to 2.76) for patients with a higher level of CRP (≥1 mg/l) versus those with a lower level of CRP (<1 mg/l). Among patients with a lower level of LDL-C, treated or not treated with statins therapy, the prevalence of multi-vessel stenosis was higher in those having a higher level of CRP than in those having a lower level of CRP (55.0% vs 41.7%, p=0.024). Further analysis was undertaken by dividing the patients into 4 categories according to CRP levels and whether or not they had statins treatment. Compared with the risk of CAD in patients with a lower level of CRP who were taking statins, the risk increased significantly when the CRP level was higher, regardless of whether they were taking statins or not. The risk was the highest (OR=2.15, 95% CI 1.08 to 4.27, p=0.029) for those with a higher level of CRP but who were not on statins therapy.

Conclusion CRP is associated with the severity of CAD. It may provide additional information regarding the risk of presenting multi-vessel stenosis even in patients with lower LDL-C.