Abstract: FR-PO0111
Role of Filtration Fraction to Predict Early Circuit Loss During CRRT with Regional Citrate Anticoagulation: A Retrospective Cohort Study
Session Information
- AKI: Epidemiology and Clinical Trials
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Chennou, Fella, University of Toronto Temerty Faculty of Medicine, Toronto, Ontario, Canada
- Abas, Dani, Universite de Montreal Faculte de Medecine, Montreal, Quebec, Canada
- Cote, Jean Maxime, Universite de Montreal Faculte de Medecine, Montreal, Quebec, Canada
Background
Continuous renal replacement therapy (CRRT) is an effective treatment modality for kidney failure in acutely ill patients. Despite circuit anticoagulation with heparin, and more recently regional citrate anticoagulation (RCA), circuit loss due to premature filter coagulation remains a costly clinical challenge. The filtration fraction (FF) equation is the ratio of ultrafiltration to plasma flow rates delivered to the filter; a high FF corresponds to higher post-filter hematocrit. Based on current guidelines and expert consensus, a FF below 0.20 to 0.25 is recommended to minimize the occurrence of filter clotting. However, the role of FF in predicting early circuit loss with RCA is uncertain.
Methods
We performed a retrospective analysis of CVVHDF episodes at a large academic center between January 2021 and December 2023. The aims of this study were to correlate the FF with circuit lifespan and assess the ability of FF to predict >48, >36 and <24 hours circuit loss by using logistic regression and calculating the area under the curve (AUC).
Results
A total of 1087 circuits from 252 patients (mean age 61 years, 68% men) were included. RCA was used in 347 circuits, whereas 713 received local circuit heparin, systemic heparin or no anticoagulation. Out of all circuits, 443 (41%) were lost due to filter clotting (<72 hours) and 126 (12%) were changed at 72 hours per protocol. The mean FF at initiation was 0.23 (SD 0.07) which was similar between the two groups. High FF correlated with lower circuit lifespan for the heparin/no anticoagulation group (Pearson coefficient: -0.307; p<0.001), but not for RCA (Pearson coefficient: 0.023; p=0.73). FF predicted >48, >36 and <24 hours circuit loss in the heparin/no anticoagulation group (beta of -1.08, -1.20 and -1.23, respectively; p<0.001), but not for RCA (beta of 0.28, 0.09, -0.28, respectively; p>0.05). The AUC to predict early circuit loss <24 hours was 0.67 [0.62-0.72](p<0.001) for heparin/no anticoagulation and 0.52 [0.44-0.62](p=0.51) for RCA.
Conclusion
Our study showed an association between FF and circuit lifespan for filters receiving heparin or no anticoagulation, however this was not observed when using RCA. FF is a modest predictor of circuit coagulation with heparin/no anticoagulation.