Increase in interleukin-6 in the first hour after coronary stenting: An early marker of the inflammatory response

Background: Inflammation after coronary stenting presages adverse outcomes after percutaneous coronary intervention (PCI). While changes in inflammatory markers have been defined 24-72 hours after PCI, potential changes during the first few hours have not. This study was designed to determine if a systemic inflammatory response could be measured within the first hour after stenting. Methods: Patients (n = 25) undergoing coronary stenting, with predominantly (n = 23) acute coronary syndromes were enrolled prospectively in this registry. Blood samples were collected before PCI, and 10 minutes, 1 hour and 18-24 hours later. No patient received a glycoprotein IIb-IIIa inhibitor. Concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), and interleukin-1 receptor antagonist (IL-1Ra) and soluble CD40 ligand (sCD40L) were measured using ELISA. Results: CRP and sCD40L did not change in the first hour after stenting. By contrast, IL-6 increased in the first hour (before = 7.6 +/- 7.7 pg/ml, 1 hour = 12 +/- 12 pg/ml; p < 0.001). The concentration of IL-1Ra tended to be greater after 1 hour (before = 426 +/- 261 pg/ml, 1 hour = 511 +/- 406 pg/ml; p = 0.11). Increase in IL-1Ra was apparent only in female subjects (p = 0.004 for the difference in trend between the two genders). A correlation was not observed between the increase in IL-6 at 1 hour and the increase in CRP at 24 hours (r = -0.21). Conclusions: In patients undergoing coronary stenting, increase in IL-6 can be detected 1 hour after PCI, and thus IL-6 may be an early initiator of the systemic inflammatory response to stenting.