Background: Recurrent vascular access thrombosis (VAT) resulting in failure to continue maintenance hemodialysis (HD) therapy is not an uncommon event. The cause of VAT in these circumstances remains uncertain. We describe results of our studies to identify changes in hemostatic balance in patients on maintenance HD therapy that probably contributed to a hypercoagulable state.
Methods: We studied 82 patients with end-stage renal disease on maintenance HD therapy who underwent HD for 11 to 52 months (39.3 +/- 27.4 months). Forty-nine episodes of VAT occurred in 22 patients; a single episode occurred in 12 patients; and 2 or more episodes, in 10 patients. Blood coagulation studies, including assays of inhibitors and activated protein C (PC) resistance (APCR), were performed using standard techniques.
Results: Investigations showed the presence of lupus anticoagulant (LA) in 5.6%, anticardiolipin antibody immunoglobulin G (IgG) in 3.9% and IgM in 5.3%, APCR in 20.5%, and deficiencies in protein S (PS), PC, and antithrombin III (ATIII) in 32.1%, 24.4%, and 19.2%, respectively. When parameters were compared between patients with and without VAT episodes, LA, PC, PS, and APCR levels were significantly abnormal in those who experienced VAT. Sixteen subjects with hypercoagulable states on HD therapy underwent renal transplantation and were evaluated 9.3 +/- 4.2 months posttransplantation. Deficiencies in PC (P = 0.014), PS (P = 0.001), ATIII (P = 0.017), and APCR (P = 0.0001) were completely corrected in all subjects.
Conclusion: Hypercoagulability is a risk factor for recurrent VAT in HD patients, and renal transplantation successfully corrects these abnormalities.