Clinical performance characteristics of hemodialysis graft monitoring

Background. Regular monitoring of dialysis grafts is recommended, but the v alue of dialysis graft blood flow monitoring and venous pressures in predic ting subsequent outcomes are controversial. Methods. Over a period of one month, we performed simultaneous flow and ven ous pressure monitoring in 71 dialysis patients with polytetrafluoroethylen e (PTFE) grafts. These patients were prospectively followed for one year. R eceiver operating characteristic (ROC) curves were constructed to evaluate the performance of the various monitoring techniques. Results. During the period of follow-up, there were 71 graft failures (30 a ngioplasty alone and 41 thrombosis followed by interventional or surgical r evisions). Failed grafts had a lower blood Row rate [799 +/- 452 (SD) mL/mi n] when compared with those without failure (1019 +/- 485 mL/min, P = 0.05) Single static or dynamic venous-pressure monitoring were not predictive of graft failure. ROC analysis showed poor performance of graft flows in pred icting graft failures over the short (30 days. AUC = 0.726, 95 % CI, 0.509 to 0.942) and long term tone year. AUC = 0.630, 95% CI, 0.499 to 0.761). An adjustment of graft Rows for systolic blood pressure or classification of graft based both on flows and venous pressure did not improve test performa nce. Conclusions. Although dialysis graft blood flow rates are statistically dif ferent in patients who have graft failure (graft angioplasty and surgery or thrombosis) versus those who do not, the performance characteristics precl ude clinical decisionmaking from an isolated blood flow or venous pressure study.