Commonly Used Antithrombotic Agents in Patients With Prolonged Partial Thromboplastin Time

Document Type

Conference Proceeding

Publication Date

1-2018

Publication Title

American Journal of Clinical Pathology

Abstract

Introduction: Partial thromboplastin time (PTT) is one of the most commonly used laboratory tests for evaluation of hemostasis. However, prolonged PTT can be paradoxical clinically, either due to bleeding disorder (factor deficiency) or thrombophilic situation (anticoagulation agents/inhibitors). It is crucial to understand the common etiologies for prolonged PTT in the interpretation of abnormal PTT results and the related patient management. Methods and Materials: This study reviews the commonly used anticoagulation medications in patients with prolonged PTT and the possible etiologies for prolonged PTT in these patients. A total of 1,140 patients were identified with prolonged PTT at the coagulation laboratory at William Beaumont Hospital in Troy, Michigan, from August 2015 to April 2016. Electronic medical charts of these patients were reviewed for anticoagulation/antithrombotic medications, including warfarin, direct oral anticoagulants (apixaban, rivaroxaban and dabigatran, or direct oral anticoagulants [DOACs]), heparin, low molecular weight heparin (LMWH) and anti-platelet agents (aspirin, Plavix, prasugrel, and ticagrelor). Results: Among the 1,140 patients, 873 (76.6%) were receiving one or more anticoagulation medications at the time with prolonged PTT, and 267 (23.4%) patients had no anticoagulation medications. In patients receiving anticoagulation medications, the numbers of medications were as follows: 281 warfarin (32.2%), 232 DOACs (26.6%), 27 heparin/LMWH (3.1%), and 333 anti-platelet agents (38.1%). There were 390 (44.7%) patients receiving two or more anticoagulation medications, and the most common second anticoagulation medication was aspirin, seen in 376 patients (43.1%). Conclusion: In this study, the majority (76.6%) of patients with prolonged PTT were receiving one or more anticoagulation/antithrombotic medications. Nearly half (47.4%) of them received warfarin, heparin/LMWH, and/or DOACs, which are likely the causes of prolonged PTT. Anti-platelet agents were seen in another 29.2% of patients, indicative of thrombophilic condition in these patients. The remaining (23.4%) patients received no anticoagulation/antithrombotic medications, and the prolonged PTT may be an indication for the evaluation of possible underlying bleeding disorders.

Volume

149

Issue

Suppl 1

First Page

S31

Comments

American Society for Clinical Pathology (ASCP) Annual Meeting, November 2-6, 2017, Kissimmee, FL

Last Page

S31

DOI

10.1093/ajcp/aqx116.070

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