The Effect of Dialysis Membranes on Coagulation Activation during Haemodialysis of Maintenance Haemodialysis Patients

Abstract Background Platelets, leukocytes, and the coagulation cascade are activated during hemodialysis. During hemodialysis, systemic anticoagulation is used to prevent clotting of the extracorporeal circuit which may lead either to complete clotting to the degree that prevent blood return to the patient or to a lesser extent can only affect the dialyzer membrane fibers which will decrease the effective surface area and that will decrease the session efficacy Aim of the Work The aim of the current study was to evaluate contact system activation and overall coagulation activation during in vivo hemodialysis in prevalent hemodialysis patients, using current generation dialyzer membranes. A crossover study design allowed assessment of differences among regular dialyzer membranes. Patients and Methods We performed a single-center sequential interventional clinical trial study. Twenty patients older than 18 years and treated with maintenance hemodialysis (3 months) underwent 2 hemodialysis study sessions at Ain Shams University hospitals dialysis unit. Exclusion criteria were clopidogrel or anticoagulant therapy, active infection, presence of central venous catheter or arteriovenous graft and known vascular access dysfunction. Results The increase of TAT at 240 minutes after dialysis start in our study, irrespective of the dialyzer membrane used, suggests a late-onset threshold for thrombin generation, which is well before the treatment effect of the UFH is expected to have faded. The changes in TAT dynamics are in line with previously published results. Dialysis treatments were standardized except for dialyzer membrane. Hence, the differences between membranes are most likely due to differences in physicochemical characteristics. Whether these differences are clinically meaningful needs further study. Analysis costs and the exploratory set-up of the trial drove the small sample size and design of the study. A more comprehensive evaluation of the coagulation activation over a longer time period of hemodialysis treatment would be of interest. Conclusion Driven by the recent interest in the therapeutic options of specific contact system inhibitors, we aimed to evaluate contact system activation during in vivo he-modialysis. Chronic hemodialysis patients dialyzed through arteriovenous dialysis access show coagulation activation during hemodialysis, marked by increased TAT levels, despite using systemic anticoagulation to prevent macroscopic clotting of the extracorporeal circuit. The increase in thrombin generation markers was not associated with measurable contact system activation. Our results argue against effective contact system activation during hemodialysis and generate the hypothesis that novel specific contact system inhibitors alone might not suffice as anticoagulant treatment during hemodialysis.