- Background Anticoagulation with heparin is recommended with intra-aortic balloon pump (IABP) to prevent thrombosis and embolization. However, anticoagulation increases the risk of bleeding, particularly in combination with glycoprotein (GP) IIb/IIIa antagonists. Hypothesis We investigated the safety of using GP IIb/IIIa antagonists without heparin after IABP insertion in patients who underwent primary percutaneous coronary intervention (PCI). Methods Consecutive patients with acute myocardial infarction (AMI), who underwent primary PCI and were treated with GP IIb/IIIa antagonists without concomitant heparin, and in whom IABP was inserted, were followed during hospitalization for thrombotic and hemorrhagic complications. Results Ninety-seven patients were included in this analysis. Glycoprotein IIb/IIIa antagonist treatment duration was 12–24 h in 89% of patients, and IABP duration was up to 48 h in 97% of patients. Three patients (3.1%) developed vascular complications: 1 had a major limb ischemia (long IABP treatment), 1 had a minor limb ischemia, and 1 had a cerebrovascular event (after prolonged resuscitation). All patients were already on heparin at the time of the thrombotic events. The rates of major and minor bleeding complications were 9% and 15.5%, respectively. Conclusions The rate of thrombotic complications is relatively low in post-primary PCI patients with IABP treated with GP IIb/IIIa antagonists without concomitant heparin therapy. Such an approach may reduce the risk of hemorrhagic complications, with low risk of thrombotic complications. Copyright © 2009 Wiley Periodicals, Inc.