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OBJECTIVES Early thrombosis (ET) contributes to autogenous arteriovenous fistula (AVF) failure. We studied patients undergoing AVF placement in the Hemodialysis Fistula Maturation (HFM) Study, a prospective, observational cohort study, using a nested case-control analysis to identify pre-operative and intra-operative predictors of ET. METHODS ET cases were compared to controls who were matched on gender, age, diabetes, dialysis status, and surgeon fistula volume. ET was defined as thrombosis diagnosed by physical exam or ultrasound within 18 days of AVF creation. Conditional logistic regression models were fit to identify risk factors for ET. RESULTS Thirty-two ET cases (5.3%) occurred among 602 study participants; 198 controls were matched. ET was associated with female gender (OR=2.75, CI 1.19–6.38, P=0.018), fistula location (forearm vs. upper arm) (OR=2.76, CI 1.05–7.23, P=0.039), feeding artery (radial vs. brachial) (OR=2.64, CI 1.03–6.77, P=0.043) and arterial diameter (OR=1.52, CI 1.02–2.26, P=0.039, per mm smaller). Draining vein diameter was nonlinearly associated with ET, with highest risk in 2–3 mm veins. Surprisingly, ET risk was lower in diabetics (OR=0.19, CI 0.07–0.47, P=0.0004), lower with less nitroglycerin-mediated brachial artery dilatation (NMD%) (OR=0.42, CI 0.20–1.92, P=0.029 for each 10% lower) and higher with lower carotid-femoral pulse wave velocity (OR=1.49, CI 1.02–2.20, P=0.041, for each m/sec lower). Intraoperative protamine use was associated with a higher ET risk (OR 3.26, CI 1.28-∞, P=0.038). Surgeon’s intraoperative perceptions were associated with ET: surgeons’ greater concern about maturation success (likely, marginal, unlikely) was associated with higher thrombosis risk (OR 8.09, CI 4.03-∞, p<0.0001, per category change), as were absence vs. presence of intraoperative thrill (OR 21.0, CI 5.07-∞, P=0.0002) and surgeons’ reported frustration during surgery (OR 6.85, CI 2.70-∞, P=0.0004). Reduced extent of intraoperative thrill (proximal, mid or distal third of the forearm or upper arm, based on AVF placement) was also associated with ET (OR 2.91, CI 1.31-∞, P=0.014, per diminished level). Oral antithrombotic medication use was not significantly associated with ET. CONCLUSIONS ET was found to be associated with female gender, forearm AVF, smaller arterial size, draining vein diameter of 2–3 mm, and protamine use. Paradoxically, diabetes and stiff, noncompliant feeding arteries were associated with lower frequency of ET. Absent or attenuated intraoperative thrill, and both surgeon frustration and concern about successful maturation during surgery, were strongly correlated with ET.

Multiple processes of care and complications are associated with AVF maturation outcomes.

National initiatives have emphasized the use of autogenous arteriovenous fistulas (AVFs) for hemodialysis, but their purported benefits have been questioned. OBJECTIVE To examine AVF usability, longer-term functional patency, and remedial procedures to facilitate maturation, manage complications, or maintain patency in the Hemodialysis Fistula Maturation (HFM) Study. DESIGN, SETTING, AND PARTICIPANTS The HFM Study was a multicenter (n = 7) prospective National Institutes of Health National Institute of Diabetes and Digestive and Kidney Diseases cohort study performed to identify factors associated with AVF maturation. A total of 602 participants were enrolled (dialysis, kidney failure: 380; predialysis, chronic kidney disease [CKD]: 222) with AVF maturation ascertained for 535 (kidney failure, 353; CKD, 182) participants. INTERVENTIONS All clinical decisions regarding AVF management were deferred to the individual centers, but remedial interventions were discouraged within 6 weeks of creation. MAIN OUTCOMES AND MEASURESIn this case series analysis, the primary outcome was unassisted maturation. Functional patency, freedom from intervention, and participant survival were summarized using Kaplan-Meier analysis. RESULTSMost participants evaluated (n = 535) were men (372 [69.5%]) and had diabetes (311 [58.1%]); mean (SD) age was 54.6 (13.6) years. Almost two-thirds of the AVFs created (342 of 535 [64%]) were in the upper arm. The AVF maturation rates for the kidney failure vs CKD participants were 29% vs 10% at 3 months, 67% vs 38% at 6 months, and 76% vs 58% at 12 months. Several participants with kidney failure (133 [37.7%]) and CKD (63 [34.6%]) underwent interventions to facilitate maturation or manage complications before maturation. The median time from access creation to maturation was 115 days (interquartile range [IQR], 86-171 days) but differed by initial indication (CKD, 170 days; IQR, 113-269 days; kidney failure, 105 days; IQR, 81-137 days). The functional patency for the AVFs that matured at 1 year was 87% (95% CI, 83.2%-90.2%) and at 2 years, 75% (95% CI, 69.7%-79.7%), and there was no significant difference for those receiving interventions before maturation. Almost half (188 [47.5%]) of the AVFs that matured had further intervention to maintain patency or treat complications. CONCLUSIONS AND RELEVANCEThe findings of this study suggest that AVF remains an accepted hemodialysis access option, although both its maturation and continued use require a moderate number of interventions to maintain patency and treat the associated complications.