Background: Hemodialysis is one of the important alternative treatments for patients with uremia, and effective hemodialysis treatment can improve mortality and quality of life. However, during hemodialysis treatment, contact between blood and artificial materials often triggers a coagulation cascade reaction, which induces dialyzer coagulation. Studies have found that the incidence of dialyzer coagulation ranges from 5% to 14%. Once coagulation occurs, it inevitably affects the efficiency of the patient's dialysis and may lead to interruption of dialysis and blood loss, with the serious possibility of systemic thromboembolic events. To prevent clotting, systemic anticoagulation is usually required, which inevitably increases the risk of bleeding and lacks safe and effective anticoagulation methods. Some studies have suggested that the endogenous coagulation pathway is the primary pathway of dialyzer coagulation and that coagulation is effectively prevented by the use of antibodies to coagulation factor F Ⅻ during extracorporeal circulation. Some studies, however, suggest that the exogenous coagulation pathway is the primary pathway of dialyzer coagulation. An in-depth study of coagulation activation will help us to understand the true mechanism of dialyzer coagulation occurrence and provide new targets for the prevention and treatment of coagulation during dialysis.

Methods: The study population consisted of 10 patients with uremia newly placed on hemodialysis treatment for the first time. Inclusion criteria: 1.70 years ≥age ≥ 18 years, gender not limited; 2.Patients with clinical diagnosis of chronic renal insufficiency (CKD stage 5) requiring renal replacement therapy; 3.Dialysis access was central venous catheter; 4.Newly placed tubing, not dialysed patients; 5.Patients voluntarily participated and written informed consent signed by the patient or authorized delegate had been obtained.Exclusion criteria: 1.Patients with acute renal failure; 2.Patients are participating in other clinical studies; 3.Pregnancy or breastfeeding; 4.Use of hemostatic or anticoagulant drugs in the last 1 week; 5.Positive infectious serum markers for HIV, syphilis, hepatitis B, and hepatitis C; 6. Presence of active infection; 7.Allergy to dialyzers.Observation index: Peripheral blood before and after dialysis and filter after dialysis were collected, and blood routine, coagulation factors, single cell sequencing and electron microscopy were performed to compare the changes of coagulation factor activity before and after contact with dialysis membrane, and to screen the major coagulation factors and coagulation pathway activation pathways. Single-cell transcriptome characteristics of peripheral blood mononuclear cells before and after exposure to dialysis membranes were analyzed to explore the key mechanisms of peripheral blood cells regulating coagulation contact activation. Statistical methods: SPSS version 17.0 statistical software was applied for statistical analysis, and continuous variables were expressed as mean ± standard deviation, and non-continuous variables were expressed as percentages. Comparisons between two data were made by independent t-test or χ2 test, and P\<0.05 was statistically significant.