The Relationship Between Neutrophil Extracellular Traps And Isolated Muscular Calf Venous Thrombosis After Artificial Joint Replacement

Objective:the incidence of deep vein thrombosis(DVT)is high after major orthopedic surgery.It is one of the main causes of perioperative death and an important cause of unexpected death in hospital.Neutrophil extracellular traps(NETs)is associated with venous thrombosis.The purpose of this study was to investigate the relationship between NETs and isolated muscular calf venous thrombosis(MCVT)in patients after total hip arthroplasty.Methods:This study was performed in 25 MCVT(+)and 53(-).The concentration of cell-free DNA(cfDNA)in platelet-poor plasma(platelet<10×10~9/L)was measured by fluorescence quantitation before the operation and 1st,3rd,6th days after the operation.C-reactive protein(CRP),D-dimer(DD),?2-plasmin inhibitor-plasmin complexes(PIC),tissue plasminogen activator-inhibitor complexes(tPAI-C),thrombin-antithrombin complex(TAT)and thrombomodulin(TM)were detected at the same time.at the same time.20 patients were randomly selected for neutrophil culture,neutrophils were stimulated by phorbol myristate acetate(PMA),and generation of NETs was performed in vitro.Cellular immunofluorescence was used as healthy control,and then the thrombus tissues of 6 patients with MVCT were detected by tissue immunofluorescence at the same time point.Results:The plasma cfDNA concentration increased significantly on the 3rd day after artificial joint replacement(p<0.01),and lasted until the sixth day after the operation,There was no difference between MCVT positive group and negative group.Pearson correlation analysis showed that there was no correlation between plasma cfDNA levels and neutrophil count on the 1st,3rd and 6th day after operation(r=0.32,0.04,0.07;p=0.78,0.97,0.95).The level of cfDNA was positively correlated with tPAI-C and TM on the 3rd day after operation(r=0.54,0.41;p<0.01,p<0.01).ROC showed that on the third day after operation,plasma cfDNA(AUC 0.52,sensitivity 21.74,specificity 96.15),D-dimer(AUC 0.60,sensitivity 80.00,specificity 40.38),cfDNA combined with D-dimer(AUC 0.64,sensitivity 86.96,specificity 29.41).When D-dimer was 0.5 mg/L EFU higher than that of the original cut-off,it indicated that the fibrinolytic system was activated when MCVT occurred.Logistic regression analysis showed that the level of D-dimer had independent predictive value(OR=1.63,p=0.02)for the formation of MCVT on the third day after operation.In vitro,stimulation of human neutrophils can produce NETs;In vivo,there are a large number of NETs and white blood cells in thrombus tissue.Conclusion:There are different degrees of vascular endothelial injury and dysfunction of coagulation and fibrinolytic system in patients with MCVT.The main results were as follows:(1)There was no significant change in plasma cfDNA level,indicating that cfDNA did not seem to be an important driver of MCVT events.(2)Plasma cfDNA is not suitable to be used alone as a biomarker for the diagnosis of MCVT.CfDNA and D-dimer can be used together to make the auxiliary diagnosis of MCVT more reliable.(3)The presence of NETs in thrombus indicates that NETs is involved in the formation of MCVT.