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Abstract: PO1036

Predictors of Vascular Access Thrombosis in Maintenance Hemodialysis Patients: An Historic Cohort Study

Session Information

Category: Dialysis

  • 703 Dialysis: Vascular Access


  • Veríssimo, Rita, DaVita Vascular Access Center - Lisbon, Lisbon, Portugal
  • Leite de sousa, Luís, DaVita Vascular Access Center - Lisbon, Lisbon, Portugal
  • Carvalho, Tiago J., DaVita Vascular Access Center - Lisbon, Lisbon, Portugal
  • Mendes, Artur P., DaVita Vascular Access Center - Lisbon, Lisbon, Portugal

Vascular access (VA) thrombosis is a known complication in patients with end-stage kidney disease on hemodialysis (HD), but its risk factors are not completely established. We performed a study with the aim of ascertaining risk factors for VA thrombosis.


A multicenter retrospective cohort study was performed in three HD units to determine VA thrombosis rate and associated risk factors in maintenance HD patients, from July 2019 to April 2021. Descriptive statistics were calculated and expressed as median (IQR) or count (%). Univariate and multivariate logistic regression was used to calculate the adjusted odds ratio (aOR) with 95% CI for the variables associated with VA thrombosis.


From a total of 178 maintenance HD patients, there were 30 (16.9%) VA thrombosis during follow-up. Our cohort had a median of 71 years (61-80), 59,6% (n=106) were male, were on HD for a median of 63.52 months (37.58-98.87), 37.6% (n=67) had diabetes, 60.1% (n=107) cardiovascular disease and 55.6% were on anticoagulant or antiplatelet agents. As to the VA, 87.1% (n=155) had arteriovenous fistulas (AVFs) and 28.1% (n=50) had history of previous percutaneous or surgical interventions. When comparing cases that led to thrombosis to VAs that maintained patency, thrombosis was more likely in arteriovenous grafts (AVGs) versus AVFs (60.9% vs 19.3%, p< 0.001), in VAs that had previous percutaneous or surgical interventions (34% vs 10.2%, p<0.001), had a VA flow (Qa) slope ≥ 25% or Qa value < 500ml/min, excluding radiocephalic AVFs (30.4% vs 11.7%, <0.001) and those with spKt/V < 1.4 (40% vs 11.2%, p<0.001). Multivariate analysis risk factors independently associated with VA thrombosis were AVGs [aOR 13.35 (4.38-40.74), p<0.001], Qa slope ≥ 25% or Qa < 500ml/min, excluding radiocephalic AVFs [aOR 5.00 (1.76-14.18), p=0.003], and spKt/V <1.4 [aOR 8.23 (2.90- 23.35), p<0.001]. The model had a Nagelkerke R2 of 42.1%, Hosmer-Lemeshow goodness-of-fit test performed well (χ2= 0.215, df=3, p=0.975) and showed very good discriminative ability [AUROC (95% CI) 0.85 (0.77-0.94)].


Our study showed AVGs, Qa slope ≥ 25% or Qa < 500ml/min, excluding radiocephalic AVFs, and spKt/V < 1.4 were independent predictors of VA thrombosis. Interestingly, patients’ demographic characteristics and comorbidities were not associated with VA thrombosis.