Background: Vascular access by dialysis graft or fistula is of major importance for hemodialysis treatment. Vascular access occlusion is one main reason for hospitalization of patients on hemodialysis. Thrombophilic risk factors are discussed as one cause for occlusion. The aim of this study was to determine if the presence of thrombophilic factors is associated with a reduced survival rate of vascular dialysis access.
Patients and methods: The following thrombophilic parameters were measured in every hemodialysis patient from five outpatient dialysis centers in Berlin: antithrombin, protein C, protein S, prothrombin mutation (G20210A), factor V mutation (G1691A), lupus anticoagulant, anticardiolipin antibodies, factor VIII, plasminogen activator inhibitor, homocysteine and lipoprotein(a). Vascular access characteristics such as vascular access material (PTFE graft or native fistula) and location were also recorded. Each patient's medical history was documented.
Results: 199 patients with a total of 499 vascular accesses in the past (311 native fistulas (62.3 %) and 188 PTFE grafts (33.7 %)) were included in this study. The type of vascular access played an important role, with mean survival times of 34.2 months for native fistulas versus 9.5 months for grafts. There was at least one thrombophilic risk factor present in 69.8 % of the patients. In the univariate analysis thrombophilia had a significant influence on vascular access survival. The effect persisted throughout the multivariate analysis. Multivariate Cox analysis showed that the presence of thrombophilic factors was associated with a 43 % (mild) to 105 % (severe thrombophilia) increased risk of occlusion of the vascular access, corresponding to a 45 % to 68 % reduction of native access survival time. The influence of thrombophilia was evident in fistulas as well as in PTFE grafts.
Conclusions: Thrombophilia plays a role in vascular accesses survival in patients on hemodialysis. In hemodialysis patients with recurrent occlusions of vascular access thrombophilia testing should be performed.