Pre-intervention eosinophil cationic protein serum levels predict clinical outcomes following implantation of drug-eluting stents

Aims Eosinophils have been identified in post-mortem studies as important players of both restenosis and thrombosis after drug-eluting stent (DES) implantation. We aimed at assessing the association between baseline levels of eosinophil cationic protein (ECP), a marker of eosinophil activation, and recurrence of clinical events in a consecutive series of patients who underwent DES implantation. Methods and results Two hundred patients (age 63 ± 10.4, males 75%) undergoing implantation of first-generation DES (Taxus or Cypher stents) were enrolled. We measured serum levels of ECP and total IgE by enzyme-linked immunosorbent assay and of C-reactive protein by high-sensitivity nephelometry prior to percutaneous coronary intervention. A clinical follow-up was planned 18 months after discharge. Major adverse cardiac events (MACEs), such as cardiac death, recurrent myocardial infarction, or clinically driven target lesion revascularization, were the endpoint of the study. Twenty-two patients (11%) had MACEs and showed higher serum levels of ECP compared with those without MACEs [30.5 (14.4–50) vs. 12.2 (4.4–31) μg/L, P = 0.004]. At simple Cox regression analysis, serum levels of ECP were a significant predictor of MACEs (hazard ratio 1.016, 95% confidence interval 1.003–1.03, P = 0.018). Conclusion This study shows for the first time an association between baseline ECP levels and the occurrence of MACEs in patients undergoing implantation of DES. Further studies are warranted to establish whether in this setting ECP is a risk marker or plays a contributory pathogenetic role.