Experiences of COVID-19 patients viscoelastometry testing and case reports

Abstract

COVID-19 is commonly associated with macro-and microvascular thrombosis and endotheliopathy. The hemostatic balance in COVID-19 is typically shifted toward a hypercoagulable state, sometimes associated with hypofibrinolysis. As a point-of-care, viscoelastic whole blood coagulation test, ClotPro® is used to measure simultaneously the function of clotting factors, platelets, blood cells and the state of fibrinolysis system. ClotPro® measurements were routinely carried out in parallel with platelet function (Multiplate®) and routine hemostasis tests from anticoagulated whole blood and plasma of SARS-CoV-2 positive patients with moderate or severe disease. Standard ClotPro® tests were the EXtest (tissue factor (TF)-activated assay), INtest (ellagic acid-activated assay), FIBtest (functional fibrinogen assay), TPAtest (r-tPA within an extrinsic pathway-based assay) and the ECAtest (ecarin-based assay). For impedance platelet aggregometry, we used arachidonic acid, ADP, TRAP and ristocetin as agonists. Platelet count was also determined. COVID-19 patients were routinely treated with LMWH and antiplatelet therapy. The hypercoagulable state could be characterized by larger and firmer clot: elevated MCF (maximal clot formation) in EX-, IN-, FIB-and TPA tests;elongated CFT (clot formation time) in ECA test;elongated LT (lysis time) in TPA (test). Tests performed using Multiplate® device have shown decreased platelet function in most cases. Even in patients without antiplatelet therapy, we found reduced ex vivo aggregation with all four agonists compared to healthy controls and the normal reference range. Viscoelastometry in COVID-19 patients revealed an increased resistance to fibrinolysis, occasionally with, fibrinolysis shutdown .