Pro-thrombotic changes in platelet, endothelial and coagulation function following haemodialysis

Abstract

Purpose: Patients on hemodialysis (HD) have an increased risk of thrombotic events, including myocardial infarction and vascular access thrombosis. The study hypothesis is that a single session of dialysis leads to platelet, endothelial & coagulation activation. Our aim is to determine the effect of a single HD session on prothrombotic vascular biomarkers before and after a single session of hemodialysis. Methods: Blood samples were taken from the vascular access of 55 patients immediately before and after a hemodialysis session. Platelet function was assessed by (1) flow cytometric measurement of P-selectin expression and fibrinogen binding ± ADP stimulation, (2) Ultegra rapid platelet function assay (RPFA) using the agonists thrombin receptor activating peptide (TRAP) and arachidonic acid (AA), (3) soluble P-selectin, and (4) soluble CD40L. Coagulation (thrombin-antithrombin III [TAT] and D-dimer), endothelial von Willebrand factor (vWF) and high sensitivity C-Reactive protein (hsCRP) were assessed by ELISA. Results: Unfractionated heparin was given to all patients during dialysis and 30 patients (55%) were on antiplatelet agents. Post-hemodialysis there were significant increases in unstimulated platelet P-selectin (p=.037), stimulated P-selectin (p<.001), soluble P-selectin (p<.001) and soluble CD40L (p=.036). Stimulated platelet fibrinogen binding was increased post-hemodialysis (p<.001) but unstimulated fibrinogen binding was unchanged. TRAP- (p<.001) and AA-(p=.009) stimulated aggregation were reduced post-hemodialysis. There were increases post-hemodialysis in TAT (p<.001), D-dimer (p<.001), vWF (p<.001) and hsCRP (p=.011). Conclusion: This study has shown that despite heparin therapy, a single session of HD induced increases in platelet, endothelial, and coagulation activation. More effective medical strategies to reduce the prothrombotic state of patients on hemodialysis should be investigated.