Impact of Protocolized Pharmacist Intervention on Critical Activated Partial Thromboplastin Time Values With Heparin Infusions

Abstract

Background: Unfractionated heparin (UFH) infusions are commonly managed with nurse-driven nomograms titrated to activated partial thromboplastin time (aPTT). In some patients, anti-Xa values may be more appropriate measures of anticoagulation. At the present institution, an update to the nurse-driven aPTT nomogram requires pharmacist notification and clinical assessment for critically supratherapeutic aPTT results. Objective: The purpose of this study was to evaluate the efficacy and safety of the nomogram update. Methods: A single-center, retrospective, pre-post analysis was conducted in patients treated with UFH who experienced a critical aPTT during the 6 months preceding and following the nomogram update. Patients with erroneous critical aPTT results were excluded. The primary endpoint was the time in therapeutic range (Rosendaal method) from the first critical aPTT until UFH discontinuation. Secondary endpoints included the proportion of patients transitioned to anti-Xa monitoring and the incidence of Bleeding Academic Research Consortium (BARC) 2, 3, 5 bleeding. Data were analyzed by the χ² test. The study was institutional review board approved. Results: Of 277 UFH infusions, 142 belonged to the pre-implementation group and 135 to the post-implementation group. Baseline aPTTs were similar between the 2 groups. Time in therapeutic range was 58.1% versus 62.4% of between groups (P = .467). UFH was transitioned to pharmacist-driven anti-Xa monitoring in 16.2% versus 40.3% of patients (P < .001). BARC 2, 3, 5 bleeding occurred in 23.2% versus 13.4% of patients (P < .001). Conclusions: Application of these data suggest improved safety and efficacy outcomes with directed pharmacist management of UFH in patients with critically elevated aPTTs.