Raymond Lamore, III, BCCCP, PharmD
Clinical Pharmacy Specialist, Critical Care
Penn Presbyterian Medical Center
Philadelphia, Pennsylvania
Disclosure information not submitted.
Lauren Schmidt, PharmD, BCCCP
Clinical Pharmacy Specialist, Critical Care
Penn Presbyterian Medical Center
Philadelphia, Pennsylvania, United States
Disclosure information not submitted.
Anju Aniyan, ACNP
Nurse Practitioner
University of Pennsylvania Health System, United States
Disclosure information not submitted.
Vanessa Prendergast, PharmD, BCPS
Clinical Pharmacy Specialist, Critical Care
Penn Presbyterian Medical Center, United States
Disclosure information not submitted.
Title: Characterization of Heparin Dosing Strategies and Outcomes in Patients with Atrial Fibrillation
Introduction: The annual rate of patient admissions involving atrial fibrillation (AF) continue to increase. Anticoagulation, commonly with intravenous heparin, remains a core aspect of inpatient management. Optimal dosing strategies are key to providing therapeutic anticoagulation while minimizing supratherapeutic levels that predispose patients to bleeding events. The objective of this quality improvement initiative was to characterize dosing practices and outcomes for inpatients with AF.
Methods: This retrospective quality improvement initiative included adult patients who were initiated on an intravenous heparin infusion for the management of AF from January 1, 2020 to March 31, 2020. Patients were included if they received at least 6 hours of heparin and used an activated partial thromboplastin time (aPTT) goal of 60 to 85 seconds, which correlates to an anti-Xa level of 0.3 to 0.7 units/mL. Patients were excluded if heparin was initiated at an outside hospital. Descriptive statistics were used to evaluate the study group.
Results: A total of 551 patients were screened within the study period; with 101 patients included. Seventy-three patients (72.3%) were ordered an initial rate of 18 units/kg/hr. Eighteen patients (17.8%) received a bolus prior to the start of the infusion. Median time to therapeutic aPTT was 16 hours (IQR, 12-26.25). In evaluating the first 48 hours of therapy, 79 patients (78.2%) had at least one aPTT > 85 seconds, and 31 patients (30.7%) had at least one aPTT > 150 seconds. During the first 48 hours of therapy, patients were supratherapeutic for a median time of 11.6 hours (IQR, 4.3-20.1). The median dose that achieved a therapeutic aPTT was 14 units/kg/hour. This cohort had a total of 2 (1.9%) minor and 5 (4.9%) major bleeding events, per the International Society of Thrombosis and Hemostasis (ISTH) criteria. Two (1.9%) patients had a stroke event.
Conclusions: Our findings demonstrate that our current dosing protocol predisposes AF patients to supratherapeutic levels, delaying time within the therapeutic range. Modifications to this protocol are being recommended to our health system anticoagulation subcommittee. These findings are likely applicable to other institutions that use a “standard” dosing scheme (18 units/kg/hour) for heparinizing patients with AF.