Arteriovenous fistula thrombosis in patients on regular hemodialysis: a report of 171 patients.

BACKGROUND Fistula thrombosis in patients on maintenance hemodialysis is an important morbidity factor. Arterial or venous thrombotic events have been described as complications in patients on regular hemodialysis. This study was designed to evaluate the risk factors for arteriovenous fistula thrombosis. METHODS One hundred and seventy-one patients with arteriovenous fistula on maintenance hemodialysis were studied prospectively during a period of 14 months for any episode of arteriovenous fistula thrombosis, after anticardiolipin antibodies were assayed by ELISA. Other risk factors for thrombosis such as the presence of diabetes or hypertension, the use of erythropoietin (rhEPO), fistula site, gender, age, ultrafiltration, hypotension during dialysis, and the number of dialysis visits in a week were assessed. RESULTS Fifty-six percent of patients had IgG-anticardiolipin antibodies > or = 10GPL, which was significantly correlated with dialysis duration (23.18 +/- 24.56 months in patients with anticardiolipin antibodies < or = 10GPL vs. 37.73 +/- 36.35 months in patients with 20 < or = IgG-anticardiolipin antibodies < 40GPL). Within the 14 months of follow-up, 36 episodes of arteriovenous fistula thrombosis occurred in 31 patients (18.1%). Considering anticardiolipin antibodies and other risk factors in a Cox proportional hazard model, only fistula site (P = 0.021, RR = 2.48, Cl = 1.14 - 5.37) and erythropoietin (Eprex) use (P = 0.021, RR = 10.92, Cl = 1.43 - 83.02) seemed to have an influence on fistula patency. According to fistula site, the survival of brachiocephalic fistulas were significantly (P = 0.007) better than radiocephalic ones (1- and 3-year survival were 95% and 87% for upper, and 88% and 72% for lower ones, respectively). CONCLUSION Although the incidence of the anticardiolipin antibody was high in our patients, in the presence of other risk factors for thrombosis, we found no correlation between IgG-anticardiolipin antibodies and arteriovenous fistula thrombosis. Instead, erythropoietin (Eprex) use and fistula site seem to have an important role in the correlation between IgG-anticardiolipin antibodies and arteriovenous fistula thrombosis.