JAMA Logo Acute coronary syndromes may cover a spectrum of unstable coronary artery and may result from an unexpected blockage in a coronary artery. Experts share that patients with acute syndromes previously treated with anticoagulant fondaparinux who underwent a coronary procedure and received a lower dose of the anticoagulant heparin during the process did not have a lowered rate of bleeding and vascular access site complications.

Prior analysis highlighted the use of unfractionated heparin as supplemental therapy during percutaneous coronary intervention for patients with non-ST segment elevation acute coronary syndromes who were seemingly treated with fondaparinux and undergoing PCI. However, background information suggests that there is disagreement on the appropriate range of dosing of heparin during PCI for these patients.

“The optimal dosing of unfractionated heparin should maintain the safety profile of fondaparinux but achieve adequate antithrombin effect to prevent catheter thrombus,” the authors share.

Experts examined the safety of two dose regimens of adjunctive intravenous unfractionated heparin during PCI in high-risk patients. The trial enlisted around 179 hospitals in 18 countries and involved 2,026 patients undergoing PCI within 72 hours, who were from a group of 3,235 high-risk patients with non-ST segment elevation acute coronary syndromes and were previously treated with fondaparinux, enrolled from February 2009 to March 2010. The individuals received either low-dose unfractionated heparin glycoprotein IIb-IIIa or standard-dose unfractionated heparin attuned by activated clotting time.

“The major bleeding events up to 30 days were similar between the low- and standard-dose groups (2.2 percent vs. 1.8 percent),” the researchers remark. “The secondary outcome of death, heart attack, or target vessel revascularization was similar, although nominally higher, in patients receiving low-dose vs. standard-dose unfractionated heparin (4.5 percent vs. 2.9 percent).”

Experts shared that the main composite outcome occurred in around 4.7 percent of the patients in the low-dose group and 5.8 percent in the standard-dose group. There was a non-significant boost in the secondary outcome reading at 5.8 percent in the low-dose group compared to 3.9 percent in the standard-dose group. Peri-PCI minor bleeding was apparently lesser in the low-dose group as against the standard-dose group.

“The finding that adding ACT-guided unfractionated heparin to fondaparinux while treating patients with acute coronary syndromes does not increase major bleeding is important in the context of modern PCI practice. Reducing bleeding is potentially important because several studies have suggested that moderate reductions in bleeding may lead to a reduction in longer term ischemic events, particularly mortality. In our study, there was no clinical benefit to using the experimental low-dose regimen, except for a reduction in minor bleeding alone (but not in the combination of major and minor bleeding),” the authors elucidate. “These findings support using the currently recommended standard ACT-guided dose of unfractionated heparin when performing PCI in patients with non-ST segment elevation acute coronary syndromes who are treated with fondaparinux.”

Scientists observed that thrombotic event were apparently not different between the treatment groups and they noticed catheter thrombosis in five cases in the low-dose group and 1 case in the standard dose group. The authors reveal that the main finding is that low fixed-dose heparin in supposedly not better than standard ACT-guided heparin dosing. This is in relation with preventing peri-PCI major bleeding or major vascular access site complications.

These findings will appear in the September 22 issue of JAMA.