Emicizumab does not interfere with the activated clotting time.

Area of Science:

• Cardiovascular Medicine
• Hematology

Background:

• Activated clotting time (ACT) is crucial for monitoring unfractionated heparin (UFH) during procedures like cardiopulmonary bypass (CPB).
• Emicizumab, a treatment for hemophilia A, may affect coagulation assays due to its mechanism of action.

Purpose of the Study:

• To evaluate the impact of emicizumab on heparin-induced ACT prolongation using the Hemochron® assay.
• To determine if emicizumab interferes with UFH monitoring in clinical settings.

Main Methods:

• High-range (HR) and low-range (LR) ACT were measured in blood samples from healthy donors, CPB patients, and emicizumab-treated patients.
• Samples were spiked with varying concentrations of UFH and/or emicizumab to assess their combined effects on ACT.

Main Results:

• Emicizumab did not mask or prevent heparin-induced prolongation of HR-ACT or LR-ACT in any tested condition.
• UFH consistently prolonged ACT in a concentration-dependent manner, irrespective of emicizumab presence.

Conclusions:

• Emicizumab does not interfere with UFH-induced ACT prolongation.
• The Hemochron® ACT assay remains a reliable tool for monitoring UFH in patients treated with emicizumab during CPB or cardiac catheterization.