Prognostic value of eosinophil to leukocyte ratio in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

Aim: Leukocyte profile has been related to clinical outcome in patients with ST-segment elevation (STE) myocardial infarction (MI). However, whether eosinophil to leukocyte ratio (ELR) predicts clinical outcome in patients who have undergone primary percutaneous coronary intervention (PCI) remains unclear. Therefore, we examined the prognostic value of ELR in this patient population. Methods: We retrospectively analyzed the data of 331 consecutive patients who underwent primary PCI for STEMI between January 2009 and March 2015. All leukocyte types were counted and ELR was calculated for all patients 24 h after hospital admission. The primary study endpoint was major adverse cardiac events (MACEs) within up to one year of follow-up duration. Results: MACEs including cardiac deaths in 9.4% of the patients, MI in 1.5%, and target lesion or vessel revascularization in 10.3%, occurred within one year in 68 patients (20.5%). The mean ELR was significantly lower in patients with MACEs than in patients without MACEs (0.20±0.51 vs. 0.49±0.66, respectively; p＜0.001). An ELR ＜0.1 at 24 h was identified as the best cut-off value for mortality prediction. Multivariate analysis identified that an ELR ＜0.1 (odds ratio [OR] =0.38; 95% confidence interval [CI]=0.22–0.67; p＜0.001) and chronic kidney disease (OR =2.38; CI=1.33– 4.24; p=0.003) are independent predictors of MACEs. Conclusion: In primary PCI patients with STEMI, ELR at 24 h was an independent predictor of MACEs in addition to the usual coronary risk factors and commonly used biomarkers.