Pre-procedural plasma levels of C-reactive protein and interleukin-6 do not predict late coronary angiographic restenosis after elective stenting

Aims Inflammatory markers may serve as an important prognostic predictor in patients with coronary heart diseases. In patients undergoing coronary interventions, it has been shown that baseline C-reactive protein (CRP) could predict late clinical restenosis. Only a few small studies have examined the possible relationship with angiographic restenosis. In patients with stable angina pectoris,we examined whether baseline CRP and IL-6 predict late coronary angiographic restenosis after stenting. Methods and Results Pre-procedural plasma levels of CRP and IL-6 were measured in 216 patients with stable angina pectoris undergoing elective coronary stenting. Angiographic follow-up was performed in all patients at 6 months. Baseline CRP levels were 6.15±0.78 mg/L versus 5.24±1.17 mg/L in the patent and restenosis groups, respectively (P=0.64). IL-6 levels were 0.46±0.03 ng/L versus 0.40±0.07 ng/L in the patent and restenosis groups, respectively (P=0.50). CRP levels were obtained again at the time of angiographic follow-up and were found to be similar in both groups (2.89±0.29 mg/L versus 2.61±0.63 mg/L, P=0.72). Moreover, in a sub-group of 43 patients, serial blood samples were obtained at several time points after the procedure up to 6 months. Both CRP and IL-6 plasma levels increased significantly in response to the procedure. CRP levels peaked at 3 days (11.27±1.53 mg/L versus 4.26±0.72 mg/L at baseline, P<0.0001). IL-6 levels reached maximum values after 24 h (1.08±0.14 ng/L versus 0.53±0.08 ng/L at baseline, P<0.0001). However, in this sub-group of patients, neither peak CRP nor IL-6 levels were found to predict late angiographic restenosis. Conclusions Coronary stenting is associated with transient increases in both CRP and IL-6 levels. However, pre-procedural CRP and IL-6 levels do not predict late coronary angiographic restenosis.