Von Willebrand Factor and Myeloperoxidase as Laboratory Predictive Markers of In-Hospital Survival in Severe COVID-19 Patients

Background. The severe acute respiratory syndrome of the SARS-CoV-2 virus-mediated coronavirus disease 2019 (COVID-19) highlighted the central role of immunothrombosis. Severe endothelial damage with the release of unusually large multimers of von Willebrand factor (vWF) and subsequent consumption of ADAMTS-13 is described during severe COVID-19. The activation of innate immune cells among which neutrophils contribute to the formation of extracellular neutrophil traps (NETs) and to the release of myeloperoxidase (MPO) potentially contributing to the spread of inflammation and microvascular thrombosis. Objective to evaluate the ability of vWF, ADAMTS-13 and MPO to predict in-hospital mortality in severe COVID-19 patients needing mechanical ventilation. Methods. We performed a one-center observational study of 79 severe COVID-19 patients entering intensive care unit for mechanical ventilation, examining vWF, ADAMTS-13 and MPO among other potential predictors for in-hospital death. Results. After multivariate analysis, vWF antigen (vWF:Ag) and MPO antigen (MPO:Ag) were finally the single two parameters which increasing values were independently associated with non-survival; vWF:Ag (U/dL): adjusted OR 3.360, 95% CI 1.5627.228, p = 0.0019; MPO:Ag (ng/ml): adjusted OR 1.062, 95% CI 1.0241.101, p = 0.0011. From these results a simplified mortality score was derived and patients categorized as having a score value higher or lower that the median value of the score: a high score value was associated with a lower cumulative survival rate (p 0.0001), 50% of the cases being dead at day 13 post-hospital admission. Conclusions. In severe COVID-19 necessitating mechanical ventilation, increasing values of MPO activity and of vWF antigen tested at admission are associated with poor survival.