Dabigatran as first-line treatment for heparin-induced thrombocytopenia in the intensive cardiac care setting

Abstract

Abstract Introduction Heparin-induced thrombocytopenia (HIT) is a rare immune-mediated disorder related to the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) which is associated with increased risk of vascular thrombosis. HIT constitute a relevant and not so uncommon clinical issue in the intensive cardiac care unit setting. Parenteral non-heparin anticoagulants are recommended for the treatment of HIT. The efficacy of dabigatran, direct oral anticoagulant, is poorly documented in this indication. In laboratory-confirmed HIT only few cases with short-term use and early conversion to and from another anticoagulant were reported. Purpose The purpose of our study was to evaluate the efficacy and safety of dabigatran as a first-line and the only one anticoagulant used in the treatment of HIT. Methods We prospectively enrolled 5 patients with the diagnosis of HIT who were hospitalized in our intensive cardiac care unit in 2017–2021. Heparin was stopped immediately on the suspicion of HIT and off-label dabigatran therapy was initiated the same day. There were no conversion to another non-heparin anticoagulant – dabigatran was used continuously from suspicion of HIT for at least 3 months. In all patients we used latex immunoassay to confirm the diagnosis of HIT. Lower-extremity compression ultrasonography was performed to exclude thrombosis. We distinguished HIT with thrombosis (HITT) and isolated HIT (HIT without thrombosis). The minimal follow-up period on dabigatran treatment was 3 months and the maximal 4 years. Results All the patients were male with the median age of 73 years (interquartile range, 52–78 years) and all were exposed to both, UFH and LMWH. The median platelet (PLT) count before exposition to heparin was 182000/μl (interquartile range, 171000/μl–321000/μl). Platelet count fall >50% was observed after a median time of 9 days (interquartile range, 7–11 days) after exposition to heparin and a median PLT count nadir was 87000 μl/l (interquartile range, 25000/μl–103000/μl). Two patients had intermediate and three high probability of HIT. HITT was diagnosed in one patient. The manifestation of HITT was upper-extremity arterial thrombosis and pulmonary embolism. Four patients were diagnosed with isolated HIT. PLT count recovery >15ehab724.2982/μl was observed after a median time of 3 days on dabigatran treatment (interquartile range, 2–7 days). In the patient with HITT, a complete resolution of upper-limb arterial thrombosis was observed. At the minimal observation period end point (3 months) all the patients survived without bleeding or new thrombotic event. Moreover, neither bleeding nor recurrence of HIT occurred during the total follow-up period. Conclusion Dabigatran is safe and efficient as first-line treatment for HIT and can be used as the only one anticoagulant in this challenging, clinical scenario. Funding Acknowledgement Type of funding sources: None.