Abstract 12891: Protocol Driven Therapeutic Efficacy of Intravenous Unfractionated Heparin in the Current Era

Introduction: Despite years of refining algorithms, intravenous (IV) unfractionated heparin (UFH) is associated with many limitations in the inpatient setting. Low-molecular-weight heparin (LMWH) has shown to be equivalent to UFH in the treatment of acute venous thromboembolic disease (VTE), and demonstrated superiority in acute coronary syndrome (ACS). LMWH has less pharmacokinetic variability, a longer plasma half-life, and is associated with fewer complications. UFH also requires frequent activated partial thromboplastin time (aPTT) monitoring, affecting hospital resources. The objectives of this study were to assess the real-word therapeutic impact of routine IV UFH use in the setting of a hospital-based algorithm, evaluate the number of patients eligible for substitution with LMWH, and estimate the cost differential. Hypothesis: Methods: Adult patients who received greater than 24 hours of IV UFH from 8/1/21 to 9/30/21 (n=174), were included in this retrospective evaluation. A random sample of 100 of these 174 patients was analyzed for aPTT results in hours 25-48. These 100 patients were also considered for theoretical substitution with LMWH. Ineligibility for substitution included intermittent and continuous renal replacement therapy (RRT), creatinine clearance less than 30 mL/min, and a planned invasive procedure within 24 hours. Fiscal analyses were also done. Results: Among 519 aPTTs drawn from these 100 patients, 348 (67%) were not within the hospital therapeutic range. The most common indications for anticoagulation were ACS and acute VTE. Eighty-one percent of patients on UFH were eligible for LMWH substitution. Ineligibility was most commonly secondary to renal dysfunction. Estimated drug acquisition costs were similar, but overall cost was lower with LMWH due to decreased laboratory testing, nurse/patient contact time, and infusion supplies. Conclusions: In spite of current hospital-based algorithms and electronic order sets to minimize variability, achieving a therapeutic aPTT during the day after UFH initiation, remained elusive. The majority of patients receiving IV UFH were eligible for substitution with LMWH. Patients who qualify, should be placed on the simpler and more reliable antithrombotic LMWH regimen.