A Multicenter Retrospective Evaluation of Direct Oral Anticoagulants for the Treatment of Heparin-Induced Thrombocytopenia.

Abstract

Direct oral anticoagulants (DOACs) represent an off-label but potential alternative to traditional therapies for heparin-induced thrombocytopenia (HIT). The objective of this study was to evaluate the efficacy and safety of DOACs in patients with a diagnosis of laboratory-confirmed HIT. A multicenter retrospective cohort study of adult patients with HIT treated with apixaban, rivaroxaban, or dabigatran between 1 January 2013 and 1 January 2020 was performed. Patients with an intermediate or high pre-test probability for HIT and a positive antiplatelet factor 4/heparin complex assay, latex immunoturbidimetric assay, or serotonin release assay were included for analysis. The primary outcome was the composite of newly diagnosed venous or arterial thromboembolism, gangrene, or severe limb ischemia requiring amputation at 3 months following DOAC initiation. This study was approved by local institutional review boards, and the requirement for informed consent was waived. A total of 77 patients from four health systems were included. The median 4Ts score was 5 (interquartile range 4.5-6), and 38 patients (49.4%) had a diagnosis of HIT with thrombosis. The most frequently used DOAC was apixaban (n = 51), followed by rivaroxaban (n = 24) and dabigatran (n = 2). In total, 63 (81.8%) patients received parenteral non-heparin anticoagulation prior to DOAC initiation. Nine patients (11.7%) experienced the primary outcome of HIT-related thrombotic events. Of the 14 patients who exclusively received DOAC therapy, none experienced the primary outcome. Major bleeding occurred in five (6.5%) patients. In this retrospective cohort study, DOACs were associated with rates of thrombotic and hemorrhagic events similar to those with other therapies currently used in the treatment of HIT.