Imbalance between procoagulant factors and natural coagulation inhibitors contributes to hypercoagulability in the critically ill COVID-19 patient: clinical implications

Coronavirus Disease-2019 (COVID-19) predisposes patients to thrombosis which underlying mechanisms are still incompletely understood. We sought to investigate the balance between procoagulant factors and natural coagulation inhibitors in the critically ill COVID-19 patient and to evaluate the usefulness of hemostasis parameters to identify patients at risk of venous thromboembolic event (VTE).We conducted an observational study recording VTEs defined as deep vein thrombosis or pulmonary embolism using lower limb ultrasound (92% of the patients), computed tomography pulmonary angiography (6%) and both tests (2%). We developed a comprehensive analysis of hemostasis.Ninety-two consecutive mechanically ventilated COVID-19 patients (age, 62 years [53-69] (median [25th-75th percentiles]); M/F sex ratio, 2.5; body-mass index, 28 kg/m2 [25-32]; past hypertension (52%) and diabetes mellitus (30%)) admitted to the Intensive Care Unit (ICU) from 03/11/2020 to 5/05/2020, were included. When tested, patients were receiving prophylactic (74%) or therapeutic (26%) anticoagulation. Forty patients (43%) were diagnosed with VTE. Patients displayed inflammatory and prothrombotic profile including markedly elevated plasma fibrinogen (7.7 g/L [6.1-8.6]), D-dimer (3,360 ng/mL [1668-7575]), factor V (166 IU/dL [136-195]) and factor VIII activities (294 IU/dL [223-362]). We evidenced significant discrepant protein C anticoagulant and chromogenic activities, combined with slightly decreased protein S activity. Plasma D-dimer3,300 ng/mL predicted VTE presence with 78% (95%-confidence interval (95% CI), 62-89) sensitivity, 69% (95% CI, 55-81) specificity, 66% (95% CI, 51-79) positive predictive value and 80% (95% CI, 65-90) negative predictive value [area under the ROC curve, 0.779 (95%CI, 0.681-0.859), p=0.0001].Mechanically ventilated COVID-19 patients present with an imbalance between markedly increased factor V/VIII activity and overwhelmed protein C/S pathway. Plasma D-dimer may be a useful biomarker at the bedside for suspicion of VTE.