Eosinopenia in patients with acute myocardial infarction- longitudinal imaging insights from the CAPRI study

Eosinophils are recruited to the heart during acute myocardial infarction (MI) and are considered part of the inflammatory response associated with adverse clinical outcomes. We assessed the impact of eosinopenia on cardiac imaging biomarkers in patients presenting with ST-segment elevation MI. This is a post-hoc analysis of the Evaluating the effectiveness of intravenous Ciclosporin on reducing reperfusion injury in pAtients undergoing PRImary percutaneous coronary intervention (CAPRI) trial. Patients underwent cardiac MRI within 1 week and 12 weeks and low eosinophil was defined as less than 40 cells/ml. The study included 52 patients and 38% had low eosinophil. Ciclosporin administration was comparable between patients with low versus normal eosinophils. The ischaemia time was significantly longer in low eosinophil patients [262 (205-325) vs. 138 (102-195) minutes, P < 0.001]. At 12 weeks, patients with eosinopenia had larger infarct size [9.8% (5.7-18.4) vs. 7.4% (1.9-10.2), P = 0.045], larger left ventricle (LV) end systolic volume (89 ± 28 vs. 68 ± 23, P = 0.02), and lower LV ejection fraction (EF) (49 ± 9 vs. 58 ± 7, P < 0.001). After adjustments for significant predictors, including ischaemia time, low eosinophil count was an independent predictor of worse LVEF at 12 weeks [-5.78, 95% CI (-11.22 to -0.34), P = 0.038] but not infarct size [1.83, 95% CI (-2.77 to 6.43), P = 0.43]. Patients with low eosinophil count had larger infarct size and LV volumes and worse adverse remodeling compared to those with normal eosinophil count. At 12 weeks, eosinopenia was an independent predictor of worse LVEF but not infarct size.