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Abstract: PO1100

Predictors of Extracorporeal Circuit Clotting in Patients Requiring Continuous Renal Replacement Therapy

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Towers, William F., Methodist University Hospital, Memphis, Tennessee, United States
  • Samarin, Michael J., Methodist University Hospital, Memphis, Tennessee, United States
  • Padgett, Danielle L., Methodist University Hospital, Memphis, Tennessee, United States
  • Hastings, Margaret Colleen, The University of Tennessee Health Science Center, Memphis, Tennessee, United States
  • Hudson, Joanna Q., The University of Tennessee Health Science Center, Memphis, Tennessee, United States

Extracorporeal circuit (ECC) clotting frequently occurs during continuous renal replacement therapy (CRRT) resulting in treatment interruption, blood loss and increased resource use. The purpose of this study was to evaluate risk factors for ECC clotting in patients receiving CRRT.


A retrospective chart review was conducted to identify adult patients who received CRRT at Methodist Le Bonheur Healthcare for a minimum of 24 hours during January 2015 to October 2019. The primary outcome was the occurrence of ECC clotting which was defined as documentation of a thrombotic event in the ECC. Demographic and laboratory data, anticoagulant medications, and CRRT parameters were evaluated for a maximum of 7 days to determine potential risk factors for clotting. Multivariable logistic regression was used to identify predictors of clotting.


A total of 200 patients were included: [108 (54%) male; mean age 56±13 years; mean sequential organ failure assessment score 12±4; 52 (26%) with past medical history of liver disease; 143 (72%) with acute kidney injury; mean duration of CRRT 3.6±2.0 days; 97% receiving continuous venovenous hemodiafiltration]. Overall, 131 (66%) patients experienced an ECC clot with a mean time to first ECC clot of 1.3±1.3 days. Patients receiving an unfractionated heparin (UFH) infusion (n=25) had a lower probability of an ECC clot occurring compared to those receiving no anticoagulation (n=86) (40% and 70%, respectively; p=0.01) and those receiving prophylactic UFH (n=70) (40% and 64%, respectively; p=0.04). Factors associated with an increased odds of clotting in patients not receiving an anticoagulant were non-African American race [odds ratio (OR) 4.0; 95% confidence interval (CI) 1.1-14.6], lower blood flow rates (OR 1.01; 95% CI 1.0-1.03), internal jugular catheters (OR 3.32;95% CI 1.1-9.9), and no history of hypertension (OR 4.79; 95% CI 1.4-16).


This study suggests a high rate of ECC clotting, particularly in patients not receiving anticoagulation. Eligible patients on CRRT should receive an UFH infusion in preference to no anticoagulation or prophylactic UFH.