Presentation Details
| Evaluation of anticoagulation management in patients with suspected heparin-induced thrombocytopenia awaiting diagnosis confirmation Alyssa R.George, Katelyn Sylvester, Dareen Kanaan, Delaney Corcoran, Kenneth Lupi, Brian Schuler, Jean M.Connors. Brigham and Women's Hospital, Boston, MA, USA |
Abstract
Background: Heparin-induced thrombocytopenia (HIT) is a severe, prothrombotic, immune-mediated complication associated with the use of heparin. The 2018 American Society of Hematology guidelines recommend discontinuation of heparin products upon suspicion of HIT and initiation of a non-heparin anticoagulant while awaiting a definitive diagnosis. Despite these recommendations, patients are not always switched to an alternative anticoagulant even with an intermediate to high probability of HIT. We switched laboratory tests at our institution from a platelet factor 4 (PF4) enzyme-linked immunosorbent assay (ELISA; Immucor), which is run once daily, to the HemosIL AcuStar HIT-IgG (Werfen) test in October 2022 to expedite turnaround time; it is run on demand with an estimated result time of less than 2 hours. Objective: Our aim is to evaluate anticoagulation prescribing practices before and after the switch in laboratory assay to determine the influence of this new test on initial management of HIT, including discontinuation of heparin products and initiation of non-heparin anticoagulants. Methods: This was a single-center, retrospective, quality-improvement analysis performed at Brigham and Women’s Hospital and approved by the Mass General Brigham Institutional Review Board. Eligible subjects included adult patients tested for suspected HIT. Those included in the ELISA (Immucor) group were tested between February 1-April 30, 2022, and those in the HemosIL AcuStar HIT-IgG (Werfen) group between February 1-April 30, 2023. Patients were excluded if they did not receive any heparin products prior to testing. The major outcome is the percentage of patients transitioned to a non-heparin anticoagulant at the time of PF4 test ordering. Minor outcomes include the development of new or worsening bleeding (major and clinically relevant non-major bleeding as defined by the International Society on Thrombosis and Haemostasis) or thrombosis (venous thromboembolism (VTE), stroke, or arterial thrombus) within 72 hours of PF4 test order. Results: Of the 123 patients identified in the Werfen group, 104 were eligible for analysis. The most common indication for heparin use was VTE prophylaxis (60.9%), with the majority receiving subcutaneous heparin (44.3%). The median time from PF4 test order to result was 163 minutes. The median provider-calculated 4T score was 5; median pharmacist-calculated 4T score was 4. Two patients had a positive PF4 result (1.9%). Heparin was discontinued at the time of PF4 test ordering in 85 patients (73.9%), however a non-heparin anticoagulant was started in only 12 patients (14.1%) while awaiting results. New or worsening thrombosis occurred in 12 patients (10.4%) within 72 hours following PF4 test ordering. Ten of these patients were continued on heparin throughout the diagnostic period. New or worsening bleeding occurred in 53 patients (46.1%) with majority of cases (56.6%) defined as minor bleeding. Results for the Immucor group are currently pending. Conclusion: This study will describe current prescribing practices surrounding initial anticoagulation management and clinical outcomes in patients with suspected HIT before and after implementation of a PF4 assay with faster turnaround time. The results may aid in optimizing institutional guidelines to improve patient care and determining the need for further electronic decision support.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.