title: Does blood flow accurately predict thrombosis or failure of hemodialysis synthetic grafts? A meta-analysis.
abstract: A number of studies have reported that a single low blood flow (Qa) measurement in synthetic hemodialysis grafts predicts thrombosis or failure. In a meta-analysis of these studies, we computed receiver operating characteristic (ROC) curves that evaluated the predictive accuracy of a Qa measurement. The ROC curves plotted sensitivity versus false-positive rate for predicting thrombosis or failure at different Qa thresholds. A perfect predictor has an area under the curve (AUC) of 1.0, whereas a predictor with no discriminative ability has an AUC of 0.5. We identified studies through a literature search and included our own unpublished data. A random-effects model was used to combine the ROC curves from different studies. Of 19 identified studies, 12 were suitable for computing binormal ROC curves (6 predicted thrombosis; 6 predicted failure). The studies measured Qa and then observed outcome during periods of 1.5 to more than 6 months. The combined AUCs from these studies indicate Qa was a relatively poor predictor, with 0.70 +/- 0. 04 (range, 0.61 to 0.84) for thrombosis and 0.76 +/- 0.07 (range, 0. 62 to 0.90) for failure. The wide range of AUCs also shows there was much heterogeneity between studies. We conclude that a single Qa measurement does not appear to have enough accuracy to be a clinically useful predictor of graft thrombosis or failure. Serial Qa measurements and identification of factors that caused heterogeneity between studies may be needed to achieve sufficient accuracy.
authors.affiliation: Division of Nephrology and Hypertension, Louisiana State University Medical Center, Shreveport, LA, USA. wpauls@lsumc.edu
authors.forename: W D
authors.initials: WD
authors.lastname: Paulson
authors.forename: S J
authors.initials: SJ
authors.lastname: Ram
authors.forename: C G
authors.initials: CG
authors.lastname: Birk
authors.forename: J
authors.initials: J
authors.lastname: Work
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology*; D019544:Equipment Failure Analysis; D005260:Female; D006083:Graft Occlusion, Vascular / Q000097:blood / Q000175:diagnosis* / Q000628:therapy; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012008:Recurrence; D006435:Renal Dialysis; D012212:Rheology