The value of peripheral blood eosinophil count in predicting in-stent restenosis in patients with stable angina pectoris undergoing drug eluting stenting

INTRODUCTION: In-stent restenosis (ISR) remains a major limitation of percutaneous coronary intervention (PCI). A role for peripheral blood cells as major regulators of immune and inflammatory systems has been proposed. We aim to evaluate the relationship between eosinophil count and development of restenosis after drug-eluting stent (DES) implantation. METHODS: In this prospective study, all consecutive patients undergoing elective DES implantation for chronic stable angina (CSA) in a university-affiliated heart center within a 6-month period were enrolled and followed for another 6 months. Complete blood count with differentiation was performed 6 weeks after the index procedure. During the follow-up period, the cohort of patients who developed ISR was compared to the cohort of patients without ISR, descriptively and the total number of eosinophilic white cells was used to predict the occurrence of ISR. RESULTS: 153 men and 48 women with CSA underwent PCI with DES implantation, from which, 26 patients needed repeat coronary angiography for recurrent symptoms. There was an established ISR in 17 (8.5%) patients. The total number of eosinophils in their peripheral blood was 267 ± 132 cells/μL in patients with ISR, significantly higher than the number of eosinophils in those without ISR 174 ± 133 cells/μL (P-value < 0.010). Eosinophil count remained an independent predictor of ISR in multivariate analysis as the eosinophil count value over 242 cells/μL had sensitivity of 66.7% and specificity of 84.5% for the presence of ISR. CONCLUSION: The total number of eosinophils, counted 6 weeks after DES implantation, prevails as the sole predictor of ISR occurrence in our study. This suggests an association between immune sensitivity reaction to DES material and development of ISR in patients after PCI.