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Continuous renal replacement therapy in COVID-19-associated AKI: adding heparin to citrate to extend filter life-a
Eduardo de Oliveira Valle1, Carla Paulina Sandoval Cabrera1, Claudia Coimbra César de Albuquerque1
1Hospital das Clínicas, University of São Paulo School of Medicine, Av. Dr. Arnaldo, 455, 3º andar, sala 3310, São Paulo, SP, CEP 01246-903, Brazil.
Insights
Adding unfractionated heparin to citrate anticoagulation for continuous renal replacement therapy (CRRT) in COVID-19 patients with acute kidney injury (AKI) reduces filter clotting. This strategy prolongs filter survival without increasing bleeding risks.
Area of Science:
- Nephrology
- Critical Care Medicine
- Hematology
Background:
- Coronavirus disease 2019 (COVID-19) is associated with thrombotic events, complicating management in patients requiring continuous renal replacement therapy (CRRT).
- Optimal anticoagulation strategies for CRRT in COVID-19 patients with acute kidney injury (AKI) remain under investigation.
- Filter clotting is a significant challenge during CRRT, potentially leading to treatment interruption and adverse outcomes.
Purpose of the Study:
- To evaluate the impact of different anticoagulation protocols on filter clotting risk in patients undergoing CRRT.
- To compare the efficacy and safety of citrate-only versus citrate plus unfractionated heparin anticoagulation in COVID-19 positive (COV+AKI) and negative (COV-AKI) patients.
- To identify risk factors associated with filter clotting during CRRT.
Main Methods:
- A retrospective observational study comparing two anticoagulation strategies: citrate alone and citrate with intravenous unfractionated heparin.
- Patients with AKI, with or without COVID-19, undergoing CRRT were included.
- Filter clotting risk, filter survival, bleeding events, blood transfusion requirements, and in-hospital mortality were compared between groups.
Main Results:
- Heparin use significantly reduced filter clotting risk (HR=0.37) and prolonged filter survival.
- Elevated D-dimer levels and high hemoglobin were identified as risk factors for circuit clotting.
- COVID-19 diagnosis was marginally associated with an increased risk of circuit clotting (HR=2.15), while heparin use was associated with a lower risk (HR=0.28).
- Bleeding events and transfusion needs were similar between anticoagulation strategies.
Conclusions:
- Adding systemic heparin to regional citrate anticoagulation in COVID-19 patients with AKI may prolong CRRT filter patency.
- This combined anticoagulation strategy reduces filter clotting risk with a low incidence of complications.
- Heparin anticoagulation is a viable option to improve CRRT circuit longevity in critically ill patients, including those with COVID-19.
Background:
Coronavirus disease 2019 (COVID-19) may predispose patients to thrombotic events. The best anticoagulation strategy for continuous renal replacement therapy (CRRT) in such patients is still under debate. The purpose of this study was to evaluate the impact that different anticoagulation protocols have on filter clotting risk.
Methods:
This was a retrospective observational study comparing two different anticoagulation strategies (citrate only and citrate plus intravenous infusion of unfractionated heparin) in patients with acute kidney injury (AKI), associated or not with COVID-19 (COV + AKI and COV - AKI, respectively), who were submitted to CRRT. Filter clotting risks were compared among groups.
Results:
Between January 2019 and July 2020, 238 patients were evaluated: 188 in the COV + AKI group and 50 in the COV - AKI group. Filter clotting during the first filter use occurred in 111 patients (46.6%). Heparin use conferred protection against filter clotting (HR = 0.37, 95% CI 0.25-0.55), resulting in longer filter survival. Bleeding events and the need for blood transfusion were similar between the citrate only and citrate plus unfractionated heparin strategies. In-hospital mortality was higher among the COV + AKI patients than among the COV - AKI patients, although it was similar between the COV + AKI patients who received heparin and those who did not. Filter clotting was more common in patients with D-dimer levels above the median (5990 ng/ml). In the multivariate analysis, heparin was associated with a lower risk of filter clotting (HR = 0.28, 95% CI 0.18-0.43), whereas an elevated D-dimer level and high hemoglobin were found to be risk factors for circuit clotting. A diagnosis of COVID-19 was marginally associated with an increased risk of circuit clotting (HR = 2.15, 95% CI 0.99-4.68).
Conclusions:
In COV + AKI patients, adding systemic heparin to standard regional citrate anticoagulation may prolong CRRT filter patency by reducing clotting risk with a low risk of complications.
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