PMC8184338_01
Clinical course in the ECMO-supported COVID-19 patient. (a) Anticoagulant argatroban was administered throughout the provision of venovenous ECMO. Anticoagulation effect. (b) Time course of platelets and results of the ELISA test (ZYMUTEST  HIA IgG). Anti-heparin/PF4 antibodies detected by optical density (OD) read on days 12, 14, and 20 were monitored by measuring activated partial thromboplastin time (aPTT) and thrombin time (TT). (c) Time course of fibrinogen, D-dimer, and C-reactive protein (CRP). (d) Undulating course of coagulation time (CT) in intrinsic (IN) and ecarin (ECA) tests in contrast to the relatively uniform course of aPTT measurement.
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We relied on careful laboratory monitoring to guide argatroban dosage (Figure 1(a)). On day 12, the patient's platelet count had decreased to a nadir of 61 G/L (Figure 1(b)). The time course of the acute-phase proteins C-reactive protein and fibrinogen and elevated D-dimer levels indicating active blood clotting is shown in Figure 1(c). The patient was highly positive for anti-PF4/heparin antibodies (optical density (OD): 2.63) as determined by the enzyme-linked immunosorbent assay (Figures 1(a)-1(d)), indicating a high likelihood of HIT. HIT, both the cannulas and the ECMO system were replaced by nonheparin-coated ECMO circuits (SOFTLINE circuits; Maquet Cardiopulmonary GmbH; Rastatt, Germany), resulting in the normalization of the platelet count within 4 days (Figure 1(b)). However, we could not revert the clinical situation.