Objective: Drugs currently in use for the management of heparin-induced thrombocytopenia (HIT) have their limitations. Several new oral anticoagulants (NOACs) such as dabigatran, rivaroxaban and apixaban may offer attractive therapy options for HIT. Although the clinical data are sparse on this topic, we have summarized the available clinical data, discussed pertinent in-vitro studies and provided the rational and advantages of using NOACs in patients with suspected or confirmed HIT. We have also reviewed the safety and efficacy of these NOACs in patients with HIT based on published literature.
Methods: We reviewed all suspected or confirmed HIT cases treated with NOACs and indexed in English language in MEDLINE and EMBASE by July 2015. The bibliography of each relevant article was searched for additional reports. In-vitro studies and other pertinent literature were briefly discussed.
Results: A total of 36 HIT patients were treated with the following NOACs: rivaroxaban (50%), dabigatran (36%) and apixaban (14%). Sixty-one percent of patients received argatroban bolus before NOACs and 3% received rivaroxaban after a lack of response with three-day course of fondaparinux. Three percent (n=1) received rivaroxaban after the patient responded to intravenous immunoglobulin for 2 days, following a lack of response to fondaparinux and bilvalirudin. In another 3% (n=1), prophylactic dose of rivaroxaban was used for 21 days and then changed to dabigatran because of persistent thrombocytopenia. All cases responded with early signs of clinical improvement and increase in platelet counts. A follow-up after a median 47 days (range 4- 450) reported no bleeding or thrombotic complications.
Conclusion: In this review, all patients with HIT treated with NOACs responded without any bleeding or thrombotic complication. Although the argatroban bolus might have contributed to a response in some patients, response to NOAC alone in other patients and in-vitro studies provide a proof of principle that NOACs can be effective in the management of HIT. Additionally, properties such as rapid onset of action, oral administration, ease of use and a lack of need for monitoring make these drugs attractive options for HIT. However, given several limitations of prior reports, further confirmation of the results are desirable.
Keywords: Apixaban, argatroban, dabigatran, heparin-induced thrombocytopenia, new oral anticoagulants, rivaroxaban.