Safety and efficacy of argatroban monitoring using a fixed activated partial thromboplastin time

Introduction: The argatroban package insert recommends monitoring for both safety and efficacy with an activated partial thromboplastin time (aPTT) goal range, created by multiplying the patient’s baseline aPTT by 1.5 and 3, not to exceed 100 seconds. If a baseline aPTT is unavailable, The University of Kansas Health System (TUKHS) recommends using a fixed aPTT goal range of 45-85 seconds. The purpose of this study was to evaluate the safety and efficacy of using a fixed aPTT goal of 45-85 seconds as compared to a patient-specific aPTT goal. Methods: This was a retrospective, single-center case control chart review of argatroban infusions titrated to a fixed aPTT range of 45-85 seconds versus a calculated patient-specific aPTT range. Patients 18 years or older were included if they received an argatroban infusion. Patients were excluded from the study if they received argatroban for less than 1 hour or if the indication for argatroban infusion was percutaneous coronary intervention or left ventricular assist device thrombosis. The primary outcome was the percent of aPTT levels within the range of 45-85 seconds for patients receiving argatroban. Secondary outcomes were the percent of aPTT values within the prescribed range and bleeding or thrombotic events. Results: A total of 146 patients were included in this study, of which 59 patients had a fixed aPTT goal range and 87 patients had a patient-specific aPTT goal range. Both groups had similar percentages of aPTT values within the 45-85 second range, 74.1% and 66.5% respectively (p = 0.09). Four patients (6.7%) with a fixed aPTT goal range and 6 patients (6.8%) with a patient-specific goal range experienced bleeding events (p = 0.978), and no patients experienced thrombotic events. Conclusions: The results of this study showed that regardless of how the target monitoring parameter was ordered, there was no statistically significant difference in the percent of aPTT values within the 45-85 second aPTT goal range. There was also no significant difference in bleeding or thrombotic events for patients among both groups. The results of this study may be used to implement a change to argatroban monitoring at TUKHS to a fixed aPTT goal range of 45-85 seconds to promote consistency in the ordered goal ranges without impacting patient safety.