The versatile heparin in COVID‐19

Abstract Background In the recent outbreak of novel coronavirus infection in Wuhan, China, significantly abnormal coagulation parameters in severe novel coronavirus pneumonia (NCP) cases were a concern. Objectives To describe the coagulation feature of patients with NCP. Methods Conventional coagulation results and outcomes of 183 consecutive patients with confirmed NCP in Tongji hospital were retrospectively analyzed. Results The overall mortality was 11.5%, the non‐survivors revealed significantly higher D‐dimer and fibrin degradation product (FDP) levels, longer prothrombin time and activated partial thromboplastin time compared to survivors on admission (P < .05); 71.4% of non‐survivors and 0.6% survivors met the criteria of disseminated intravascular coagulation during their hospital stay. Conclusions The present study shows that abnormal coagulation results, especially markedly elevated D‐dimer and FDP are common in deaths with NCP.

Background A relatively high mortality of severe coronavirus disease 2019 (COVID‐19) is worrying, and the application of heparin in COVID‐19 has been recommended by some expert consensus because of the risk of disseminated intravascular coagulation and venous thromboembolism. However, its efficacy remains to be validated. Methods Coagulation results, medications, and outcomes of consecutive patients being classified as having severe COVID‐19 in Tongji hospital were retrospectively analyzed. The 28‐day mortality between heparin users and nonusers were compared, as was a different risk of coagulopathy, which was stratified by the sepsis‐induced coagulopathy (SIC) score or D‐dimer result. Results There were 449 patients with severe COVID‐19 enrolled into the study, 99 of them received heparin (mainly with low molecular weight heparin) for 7 days or longer. D‐dimer, prothrombin time, and age were positively, and platelet count was negatively, correlated with 28‐day mortality in multivariate analysis. No difference in 28‐day mortality was found between heparin users and nonusers (30.3% vs 29.7%, P  = .910). But the 28‐day mortality of heparin users was lower than nonusers in patients with SIC score ≥4 (40.0% vs 64.2%, P  = .029), or D‐dimer >6‐fold of upper limit of normal (32.8% vs 52.4%, P  = .017). Conclusions Anticoagulant therapy mainly with low molecular weight heparin appears to be associated with better prognosis in severe COVID‐19 patients meeting SIC criteria or with markedly elevated D‐dimer.

Hyper–inflammatory responses can lead to a variety of diseases including sepsis1. We now report that extracellular histones released in response to inflammatory challenge contribute to endothelial dysfunction, organ failure and death during sepsis. They can be targeted pharmacologically by antibody to histone or by activated protein C (APC). Antibody to histone reduced the mortality of mice in lipopolysaccharide (LPS), tumor necrosis factor (TNF) or cecal ligation and puncture models of sepsis. Extracellular histones are cytotoxic toward endothelium in vitro and are lethal in mice. In vivo, histone administration resulted in neutrophil margination, vacuolated endothelium, intra–alveolar hemorrhage and macro and microvascular thrombosis. Histone was detected in the circulation of baboons challenged with E. coli and the increase in histone levels accompanied the onset of renal dysfunction. APC cleaves histones and reduces their cytotoxicity. Co–infusion of APC with E. coli in baboons or histones in mice prevented lethality. Blockade of protein C activation exacerbated sublethal LPS challenge into lethality which was reversed by antibody to histone. We conclude that extracellular histones are potential molecular targets for therapeutics for sepsis and other inflammatory diseases.