Continuous renal replacement therapy in COVID-19-associated AKI: adding heparin to citrate to extend filter life-a retrospective cohort study.

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.

A clinical model to predict successful renal replacement therapy (RRT) discontinuation in patients with Acute Kidney Injury (AKI).

INTRODUCTION: Ideal timing of Renal Replacement Therapy (RRT) discontinuation in Acute Kidney Injury (AKI) is still unknown. We aimed to study the role of creatinine-related variables in predicting RRT successful discontinuation and to propose a clinical predictive score. METHODS: In this single-centre retrospective study, we evaluated all AKI patients in whom RRT was interrupted for at least 48 hours. Patients who were still RRT-independent 7 days after initial RRT cessation were included in the "Success" group and opposed to the "Failure" group. We evaluated baseline characteristics and variables collected at the time of RRT interruption, as well as the Kinetic estimated Glomerular Filtration Rate (KeGFR), the simple variation in serum Creatinine (ΔsCr), and the incremental creatinine ratio on the first three days after RRT interruption. Multivariable analysis was performed to evaluate prediction of success. Internal validation using a simple binomial generalized regression model with Lasso estimation and 5-fold cross validation method was performed. RESULTS: We included 124 patients, 49 in the "Failure" group and 75 in the "Success" group. All creatinine-related variables predicted success in simple and multiple logistic regression models. The best model generated a clinical score based on the odds ratio obtained for each variable and included urine output, non-renal SOFA score, fluid balance, serum urea, serum potassium, blood pH, and the variation in sCr values after RRT discontinuation. The score presented an area under the ROC of 0.86 (95% CI 0.76‒1.00). CONCLUSION: Creatinine variation between the first 2 consecutive days after RRT discontinuation might predict success in RRT discontinuation. The developed clinical score based on these variables might be a useful clinical decision tool to guide hemodialysis catheter safe removal.

Cov-hep study: heparin in standard anticoagulation based on citrate for continuous veno-venous hemodialysis in patients with COVID-19: a structured summary of a study protocol for a randomized controlled trial.

OBJECTIVES: The primary objective is to test if heparin added to a standard regional anticoagulation protocol based on citrate is able to reduce dialysis circuit losses by clotting without increasing the risk of thrombocytopenia or bleeding, in patients with COVID-19 with acute kidney injury requiring dialysis. TRIAL DESIGN: Randomized, parallel-group, open-label trial, with two arms (ratio 1:1) comparing different continuous renal replacement therapy anticoagulation strategies. PARTICIPANTS: Eligibility conditions: All ICU patients of University of Sao Paulo General Hospital (Hospital das Clínicas), Brazil will be screened for eligibility conditions. Adults (> 18 years old) with confirmed COVID-19 and acute kidney injury requiring dialysis with agreement between ICU and nephrology teams for the introduction of renal continuous replacement therapy in daily ICU rounds. Continuous renal replacement therapy will be prescribed by consulting nephrologists based on standard clinical guidelines, including acute kidney injury with hemodynamic instability plus hyperkalemia, severe acidosis, volume overload, respiratory distress, multiorgan failure or some combination of these factors. DATA COLLECTION: Patients demographics and associated clinical data and comorbidities will be recorded at ICU entry. Demographic information will include the patient's age, sex, and admission dates. Clinical data comprise comorbidities, APACHE 2, SAPS 3, need for mechanical ventilation, and use of vasopressor drugs. Physiological data collected by the day of CRRT start will be vital signs, the arterial oxygen tension/fraction of inspired oxygen (PaO2/FiO2) index, and serum creatinine, blood urea nitrogen, bilirubin, hemoglobin, hematocrit, platelets, white blood cell count levels and Peak D-dimer levels. Patients will be analyzed for the first 72h of CRRT, and they will be evaluated regarding clinical variables, filter patency and any adverse events that could be related to the anticoagulation choice, as bleeding (mild or major) or low platelets counts (<100.000 ui/uL) during treatment period. Mild and major bleeding will be defined by hemorrhagic event without clinical impact or hemoglobin (Hb) fall lesser than 1g/dL and hemorrhagic event with clinical impact or Hb fall higher than 1g/dL, respectively. EXCLUSION CRITERIA: Hypersensitivity to any of the substances going to be used in the study (Citric acid dextrosol 2.2% and unfractionated heparin); Previous diagnosis of coagulopathy or thrombophilia; Contraindication to the use of unfractionated heparin; Risk of citrate poisoning - (Lactate> 30 mg/dL, international normalized ratio > 2.5, Total bilirubin> 15 mg/dL); Pregnancy; Patients unlikely to survive for more than 24 hours. The trial is being undertaken at the University of Sao Paulo General Hospital (Hospital das Clinicas), Brazil. INTERVENTION AND COMPARATOR: Group A (control) - Patients on continuous renal replacement therapy (blood flow 150 ml/min, dose of 30 mL/Kg/h) receiving anticoagulation with sodium citrate at 4 mmol/L Group B (experiment): Patients on continuous hemodialysis (blood flow 150 mL/min, dose of 30 mL/Kg/h) receiving anticoagulation with sodium citrate at 4 mmol/L associated with unfractionated heparin at 10 U/Kg/h. MAIN OUTCOMES: The percentage of clotted dialyzers within 72 hours in each of the studied groups (Primary outcome) Secondary outcomes: Number of dialyzers used in the first 72 hours of dialysis protocol, Mortality in the first 72 h of dialysis protocol, Bleeding events (Major or minor) in the first 72 h of dialysis protocol, Thrombocytopenia (less than 50.000 platelets) proportion in the first 72 h of dialysis protocol, Dialysis efficiency (Urea sieving) - variation in urea sieving between the first, second and third days of dialysis protocol, Continuous renal replacement therapy pressures (Arterial, Venous, dialysate and pre-filter pressure) in the first 72 h of dialysis protocol, in-hospital mortality. RANDOMIZATION: RedCap→ randomization - 2 blocks randomization by D-dimer level (5000ng/dL cut-off) and catheter site (Right Internal Jugular versus other sites) with 1:1 allocation ratio. BLINDING (MASKING): No blinding - Open label format NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): Total number of patients 90 (45 per group) TRIAL STATUS: Trial version 2.0 - ongoing recruitment. First recruitment: June 29, 2020 Estimated date for last recruitment: December 31, 2020 TRIAL REGISTRATION: Responsible Party: University of Sao Paulo General Hospital (Hospital das Clinicas) ClinicalTrials.gov Identifier: NCT04487990 , registered July 27, 2020, ReBec www.ensaiosclinicos.gov.br/rg/RBR-45kf9p/ Other Study ID Numbers: U1111-1252-0194 FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1) In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

A clinical model to predict successful renal replacement therapy (RRT) discontinuation in patients with Acute Kidney Injury (AKI)

Abstract Introduction Ideal timing of Renal Replacement Therapy (RRT) discontinuation in Acute Kidney Injury (AKI) is still unknown. We aimed to study the role of creatinine-related variables in predicting RRT successful discontinuation and to propose a clinical predictive score. Methods In this single-centre retrospective study, we evaluated all AKI patients in whom RRT was interrupted for at least 48 hours. Patients who were still RRT-independent 7 days after initial RRT cessation were included in the "Success" group and opposed to the "Failure" group. We evaluated baseline characteristics and variables collected at the time of RRT interruption, as well as the Kinetic estimated Glomerular Filtration Rate (KeGFR), the simple variation in serum Creatinine (ΔsCr), and the incremental creatinine ratio on the first three days after RRT interruption. Multivariable analysis was performed to evaluate prediction of success. Internal validation using a simple binomial generalized regression model with Lasso estimation and 5-fold cross validation method was performed. Results We included 124 patients, 49 in the "Failure" group and 75 in the "Success" group. All creatinine-related variables predicted success in simple and multiple logistic regression models. The best model generated a clinical score based on the odds ratio obtained for each variable and included urine output, non-renal SOFA score, fluid balance, serum urea, serum potassium, blood pH, and the variation in sCr values after RRT discontinuation. The score presented an area under the ROC of 0.86 (95% CI 0.76‒1.00). Conclusion Creatinine variation between the first 2 consecutive days after RRT discontinuation might predict success in RRT discontinuation. The developed clinical score based on these variables might be a useful clinical decision tool to guide hemodialysis catheter safe removal.