Heparin-induced thrombocytopenia (HIT) in a COVID-19 patient on extracorporeal membrane oxygenation (ECMO) support: Case report experience with rivaroxaban

ABSTRACT

Background: HIT is an intensely procoagulant disorder and in patients on ECMO it is associated with a high thrombotic morbidity and mortality, thus is crucial to intervene early. Aim(s) To present a case of a COVID-19 patient on ECMO who was diagnosed HIT. To describe evolution on Rivaroxaban treatment due to the unavailability of parenteral non-heparin anticoagulants in our country. Method(s) Not applicable. Result(s) A 60-year- old female patient was admitted to our hospital for ECMO support. She was diagnosed with SARS-CoV2, her condition quickly worsened with pneumothorax and refractory hypoxemia hence she was referred to our Institution. ECMO and hemodialysis were required. Unfractionated heparin (UFH) was given to achieve goal anti-Xa 0.3-0.7 units/mL. Platelet count (PLT) was 278,000 / mm3 and D dimer 1844 ng/mL FEU. Next day UFH was stopped because of haemothorax. Five days after restart anticoagulation an increased transmembrane pressure and a trombi was observed in the system. PLT were 12,000/mm3 and Ddimer 8500 ng/mL FEU. HIT was suspected;4Ts score = 7 and anti-FP4 antibodies positive (5.7 UA/mL). UFH was stopped and due to inaccessibility to other intravenous anticoagulant rivaroxaban 15 mg twice daily was started. Rivaroxaban calibrated anti-Xa assay was twice daily performed to monitor trough and peak levels, 30 mg twice daily was necessary to achieve therapeutic plasma concentration. Patient's PLT recovered after 7 days. No thrombotic event was recorded during rivaroxaban use. After ECMO was weaning-off rivaroxaban dose was reduced to 10 mg/day. Ten days later she had an upper gastrointestinal bleeding because gastric ulcer and rivaroxaban was stopped. With clinical stability and non evidence of bleeding, thromboprophylaxis with rivaroxaban was restarted and continued until discharged. Conclusion(s) Our case highlights the difficulties on management of HIT in patients on ECMO support and the need for consented guidelines in this specific situation, particularly for countries without access to parenteral non-heparin anticoagulants.