Venous pressure monitoring does not accurately predict access failure in children

Access failure is a significant cause of morbidity and mortality in hemodialysis patients. Routine monitoring of arteriovenous (AV) fistulas and grafts could increase access longevity. Dynamic venous pressure monitoring is a surveillance test advocated to detect early signs of vascular thrombosis. Venous pressure measurements obtained, per DOQI recommendations, in children undergoing hemodialysis with an AV fistula or graft were reviewed. Baseline venous pressures were established by calculating the mean of venous pressures obtained without an antecedent thrombosis. A paired t-test was performed comparing mean baseline pressure measurements with pressures immediately preceding each thrombosis episode. Since some patients had multiple thrombosis episodes, the assumption of independence was not met. A second paired t-test was performed comparing mean baseline pressures with the mean pressure measurement per individual, obtained immediately preceding a thrombosis episode; 335 venous pressures were collected in ten pediatric patients. Eighteen thromboses occurred in five patients, in whom a total of 241 venous pressures were measured. Venous pressures did not correlate with thrombotic events (P=0.4284). Specific thrombotic events for each patient were correlated with mean patient-specific venous pressures and showed no correlation (P=0.3229). Dynamic venous pressure monitoring is not an adequate predictor of access thrombosis in pediatric patients.