[Long-term hemodialysis and changes in variables of coagulation and fibrinolysis]

The development of hemodialysis treatment has remarkably improved the prognosis of chronic hemodialysis (HD) patients. However, as the patient's survival time is prolonged, vascular damages due to the abnormalities of calcium and lipid metabolism and hypertension has become the important complications in HD patients. In addition to coagulation and fibrinolysis, vascular endothelial function has been pursued to clarify the pathogenesis for occurrence of thrombosis in HD patients with more than ten years' duration. Twenty-two HD patients including twelve of less than ten years' duration and ten of more than ten years' were subjected to this study. Twelve healthy controls were also involved in this study. Fibrinopeptide A (FPA) and thrombin-antithrombin III complex (TAT) as indexes of coagulation, antithrombin III (AT III) as an index of coagulation inhibitor and D-dimer as an index of fibrinolysis were measured. A special attention has been focused in changes in the levels of tissue plasminogen activator (t-PA) activity and antigen and plasminogen activator inhibitor-1 (PAI-1) as indexes of fibrinolysis capacity, representing parameters of vascular endothelial functions. Levels of FPA, TAT and D-dimer were significantly higher in HD patients when compared with those in healthy controls. In particular, levels of FPA were significantly higher in HD patients with more than ten years' duration as compared to those in HD patients with less than ten years'. AT III values were significantly lower in HD patients with more than ten years' duration than those in healthy controls. T-PA activity and antigen levels were significantly lower in HD patients than those in healthy controls. T-PA activity levels were lower in HD patients with more than ten years' duration than those in HD patients with less than ten years'. Among HD patients, a significant negative correlation was found between t-PA activity and hemodialysis duration. PAI-1 values in HD patients were not significantly differ from those in healthy controls. These results suggest that in spite of increased coagulability, fibrinolytic capacity of vascular endothelium decreased in HD patients, and that the incidence is accelerated as hemodialysis duration is prolonged. Therefore, it is concluded that long-term HD patients are in the state of a higher risk of thrombosis.