Background: Erythropoietin (EPO) enhances re-endothelialization and anti-apoptotic action. Larger clinical studies to examine the effects of high-dose EPO are in progress in patients with acute myocardial infarction (AMI).
Methods and results: The aim of this multi-center pilot study was to investigate the effect of `low-dose EPO' (6,000 IU during percutaneous coronary intervention (PCI), 24 h and 48 h) in 35 patients with a first ST-elevated AMI undergoing PCI who was randomly assigned to EPO or placebo (saline) treatment. Neointimal volume, cardiac function and infarct size were examined in the acute phase and 6 months later (ClinicalTrials.gov identifier: NCT00423020). No significant regression in in-stent neointimal volume was observed, whereas left ventricular (LV) ejection fraction was significantly improved (49.2% to 55.7%, P=0.003) and LV end-systolic volume was decreased in the EPO group (47.7 ml to 39.0 ml, P=0.036). LV end-diastolic volume tended to be reduced from 90.2% to 84.5% (P=0.159), whereas in the control group it was inversely increased (91.7% to 93.7%, P=0.385). Infarction sizes were significantly reduced by 38.5% (P=0.003) but not in the control group (23.7%, P=0.051). Hemoglobin, peak creatine kinase values, and CD34(+)/CD133(+)/CD45(dim) endothelial progenitors showed no significant changes. No adverse events were observed during study periods.
Conclusions: This is a first study demonstrating that short-term `low-dose' EPO to PCI-treated AMI patients did not prevent neointimal hyperplasia but rather improved cardiac function and infarct size without any clinical adverse effects.