Acute Kidney InjuryNCT05175053
Early RRT in AKI After Cardiac Surgery
A study testing Renal replacement therapy and Best medical management in people with Acute Kidney Injury, run by Seoul National University Hospital at 2 sites in South Korea.
Trial summary
Acute kidney injury (AKI) is one of the major complications after cardiac surgery that may affects 20% to 40% of patients according to the definitions. Also, AKI after cardiac surgery is associated with high morbidity and mortality, with eight-fold increase in the odds ratio of death when renal replacement therapy… Read more about this study
- Who is it for?
- Ages 19 years and older
- Conditions the study is for
- Acute Kidney Injury
- What is being tested?
- Renal replacement therapy and Best medical management
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 44 participants
- Where
- 2 sitesSouth Korea
- Study dates
- 24 Dec 2021to 11 Feb 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients within 7 days after cardiac surgery
- Acute kidney injury (AKI) described as Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 (urine output <0.5mL/kg/h for ≥6h or 2-fold increase in serum creatinine compared with baseline)
Who cannot join
- previous renal replacement therapy
- AKI secondary to obstructive nephropathy
- previous kidney transplantation
Trial locations and contacts
2 sites in 1 country.
South Korea2 sites
Seoul National University Bundang Hospital
Seongnam
Seoul National University Hospital
Seoul
About this study
Official title: Early Application of Renal-Replacement Therapy in Patients With Acute Kidney Injury After Cardiac Surgery: A Multicenter Randomized Controlled Trial
Acute kidney injury (AKI) is one of the major complications after cardiac surgery that may affects 20% to 40% of patients according to the definitions. Also, AKI after cardiac surgery is associated with high morbidity and mortality, with eight-fold increase in the odds ratio of death when renal replacement therapy (RRT) is required. However the indication and the optimal timing of RRT initiation are still controversial.
We hypothesized that a strategy of early initiation of RRT would result in a lower risk of surgical mortality than a standard strategy in post cardiac surgery patients with AKI of Kidney Disease: Improving Global Outcomes (KDIGO) classification stage 2 (serum creatinine, 2.0 times the baseline level; urine output, <0.5mL/kg/h for 6 or more hours).
Read the detailed description
This trial was designed as a multi-center randomized, controlled trial to recruit 202 patients who develop acute kidney injury (AKI) described as Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 (serum creatinine, 2.0 times the baseline level; urine output, <0.5mL/kg/h for 6 or more hours) after cardiac surgery. Patients were randomized in a 1:1 ratio to 1 of the 2 treatment groups (Early vs. Delayed renal replacement therapy (RRT)) using a computerized system.
Sample size determination : power calculation were performed based on the primary end point (operative mortality). The expected operative mortality in the control group with delayed initiation of RRT was 55% based on the literature. Differences between treatment groups were to be detected with a power of 80%, if the operative mortality of with early initiation of RRT was 35% or less. The expected treatment effect of 20% was calculated on the mortality differences between early and delayed RRT reported in previous studies. A required sample size for the final analysis was 101 patients per treatment group, 202 patients in total (level of significance, α = 0.05; type II error, β= 0.02; potential dropouts= 5%).
Early RRT was initiated within 6 hours of diagnosis of stage 2 AKI.
Delayed RRT was initiated if any one of the following absolute indications for RRT is present
- serum urea level higher than 100mg/dL and/or with uremic encephalopathy
- serum potassium level higher than 6mmol/L and/or with electrocardiography abnormalities
- urine production lower than 0.3mL/kg/hr for 24 hours
- pH of 7.15 or less and/or severe hypotension due to metabolic acidosis
- organ edema in the presence of AKI resistant to diuretic treatment.
The primary end point is operative mortality (described as any death, regardless of cause, occurring (1) within 30 days after surgery in or out of the hospital, and (2) after 30 days during the same hospitalization subsequent to the operation).
The secondary end points included 90 day overall survival, cardiovascular mortality, RRT dependence, and major adverse kidney events (MAKE), adverse events related to RRT or vascular access, duration of mechanical ventilator support and intensive care unit stay, and hospital length of stay.
RRT delivery
: Once RRT was initiated, both groups were treated using continuous venovenous hemodiafiltration (CVVHDF) with identical settings. Initial target dose of hemodiafiltration was 25 to 50mL/kg/hr depends on the decision of attending physician and further adjusted according to the metabolic needs of the patient. Replacement fluid was delivered into the extracorporeal circuit before the filter with a ratio of dialysate to replacement fluid of 1:1. Blood flow was maintained between 100 to 250mL/min. Regional anticoagulation with nafamostat (dosage 20-50mg/hr) was used to prevent circuit clotting if necessary.
RRT was discontinued if renal recovery defined by urine output (>1mL/Kg/hr for 8 hours or more or >1000mL/24h without diuretics; >2000mL/24h with diuretics) and creatinine clearance (>20mL/min) occurred.
If cessation criteria were not fulfilled after 7 days, conversion to intermittent hemodialysis would be considered.
- Conditions
- Acute Kidney Injury
- Being tested
- Renal replacement therapy, Best medical management
- Keywords
- Acute Kidney Injury, Post Cardiac Surgery, Renal Replacement Therapy
- Medical subject headings
- Acute Kidney Injury
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Renal replacement therapyOther
Continuous renal replacement therapy using continuous venovenous hemodiafiltration (CVVHDF)
Best medical managementOther
The best medical management continues until the patient meets absolute indication of renal replacement therapy
| Study group | Role | What they receive |
|---|---|---|
| Early RRT group | Experimental | Patients who will undergo renal replacement therapy (RRT) within 6 hours of diagnosis of stage 2 acute kidney injury (AKI). Receives: Other: Renal replacement therapy |
| Delayed RRT group | Active comparator | Patients who will undergo renal replacement therapy (RRT) if one of the absolute indications for RRT is present. Receives: Other: Best medical management |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of participants with operative mortality
any death, regardless of cause, occurring (1) within 30 days after surgery in or out of the hospital, and (2) after 30 days during the same hospitalization subsequent to the operation
Measured: at postoperative 30 days
Secondary outcomes (8)
Overall survival
overall survival
Measured: at postoperative 90 days
Number of participants with cardiovascular mortality
Any death related to cardiac events, including sudden death during follow-up
Measured: at postoperative 90 days
Number of participants with renal replacement therapy dependency
Number of participants who still needs renal replacement therapy at 90 days after operation.
Measured: at postoperative 90 days
Number of participants with major adverse kidney events (MAKE)
MAKE indicates the composite of death, need of renal replacement therapy, and persistent renal dysfunction.
Measured: at postoperative 90 days
Number of participants with renal replacement therapy related morbidity
adverse events related to renal replacement therapy (RRT) or vascular access for RRT.
Measured: at postoperative 90 days
Duration of mechanical ventilation
duration of mechanical ventilator support
Measured: at postoperative 30 days
Duration of intensive care unit stay
duration of intensive care unit stay
Measured: at postoperative 30 days
Hospital length of stay
hospital length of stay
Measured: at postoperative 30 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jan 2022
- Study start24 Dec 2021
- Primary completion11 Feb 2026
- Study completion11 Feb 2026
Why it stopped: This multicenter randomized controlled trial planned competitive enrollment across multiple sites; however, no patients were enrolled at one site. Only 44 of 202 participants were enrolled over four years, so early termination is proposed.
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute Kidney InjuryStudies of the same condition, open and under way.
- More trials run by Seoul National University HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 44 participants (actual)
Sponsor and investigators
- Lead sponsor
- Seoul National University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Seoul National University Bundang Hospital
- Responsible party
- Principal investigator, Ho Young Hwang, Seoul National University Hospital
- Investigators
- Ho Young Hwang, MD, PhD, Principal investigator, Seoul National University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05175053
- Sponsor's protocol ID
- D-2107-213-1239
- Status last verified
- Feb 2026
- First submitted
- 10 Dec 2021
- Last updated
- 12 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: IPD will not be shared because it is not allowed by our institutional IRB.
Study at a glance
From the registry record, last updated by the sponsor on 12 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Early Application of Renal-Replacement Therapy in Patients With Acute Kidney Injury After Cardiac Surgery: A Multicenter Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT05175053
- Acronym / sponsor ID
- D-2107-213-1239
- Conditions
- Acute Kidney Injury
- Keywords
- Acute Kidney Injury, Post Cardiac Surgery, Renal Replacement Therapy
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: This multicenter randomized controlled trial planned competitive enrollment across multiple sites; however, no patients were enrolled at one site. Only 44 of 202 participants were enrolled over four years, so early termination is proposed.
- Enrolment
- 44 participants (actual)
- Lead sponsor
- Seoul National University HospitalUniversity, hospital or other
- Collaborators
- Seoul National University Bundang Hospital
- Study start
- 24 Dec 2021 (actual)
- Primary completion
- 11 Feb 2026 (actual)
- Study completion
- 11 Feb 2026 (actual)
- First posted
- 3 Jan 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Acute kidney injury (AKI) is one of the major complications after cardiac surgery that may affects 20% to 40% of patients according to the definitions. Also, AKI after cardiac surgery is associated with high morbidity and mortality, with eight-fold increase in the odds ratio of death when renal replacement therapy (RRT) is required. However the indication and the optimal timing of RRT initiation are still controversial.
We hypothesized that a strategy of early initiation of RRT would result in a lower risk of surgical mortality than a standard strategy in post cardiac surgery patients with AKI of Kidney Disease: Improving Global Outcomes (KDIGO) classification stage 2 (serum creatinine, 2.0 times the baseline level; urine output, <0.5mL/kg/h for 6 or more hours).
Detailed description
This trial was designed as a multi-center randomized, controlled trial to recruit 202 patients who develop acute kidney injury (AKI) described as Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 (serum creatinine, 2.0 times the baseline level; urine output, <0.5mL/kg/h for 6 or more hours) after cardiac surgery. Patients were randomized in a 1:1 ratio to 1 of the 2 treatment groups (Early vs. Delayed renal replacement therapy (RRT)) using a computerized system.
Sample size determination : power calculation were performed based on the primary end point (operative mortality). The expected operative mortality in the control group with delayed initiation of RRT was 55% based on the literature. Differences between treatment groups were to be detected with a power of 80%, if the operative mortality of with early initiation of RRT was 35% or less. The expected treatment effect of 20% was calculated on the mortality differences between early and delayed RRT reported in previous studies. A required sample size for the final analysis was 101 patients per treatment group, 202 patients in total (level of significance, α = 0.05; type II error, β= 0.02; potential dropouts= 5%).
Early RRT was initiated within 6 hours of diagnosis of stage 2 AKI.
Delayed RRT was initiated if any one of the following absolute indications for RRT is present
- serum urea level higher than 100mg/dL and/or with uremic encephalopathy
- serum potassium level higher than 6mmol/L and/or with electrocardiography abnormalities
- urine production lower than 0.3mL/kg/hr for 24 hours
- pH of 7.15 or less and/or severe hypotension due to metabolic acidosis
- organ edema in the presence of AKI resistant to diuretic treatment.
The primary end point is operative mortality (described as any death, regardless of cause, occurring (1) within 30 days after surgery in or out of the hospital, and (2) after 30 days during the same hospitalization subsequent to the operation).
The secondary end points included 90 day overall survival, cardiovascular mortality, RRT dependence, and major adverse kidney events (MAKE), adverse events related to RRT or vascular access, duration of mechanical ventilator support and intensive care unit stay, and hospital length of stay.
RRT delivery
: Once RRT was initiated, both groups were treated using continuous venovenous hemodiafiltration (CVVHDF) with identical settings. Initial target dose of hemodiafiltration was 25 to 50mL/kg/hr depends on the decision of attending physician and further adjusted according to the metabolic needs of the patient. Replacement fluid was delivered into the extracorporeal circuit before the filter with a ratio of dialysate to replacement fluid of 1:1. Blood flow was maintained between 100 to 250mL/min. Regional anticoagulation with nafamostat (dosage 20-50mg/hr) was used to prevent circuit clotting if necessary.
RRT was discontinued if renal recovery defined by urine output (>1mL/Kg/hr for 8 hours or more or >1000mL/24h without diuretics; >2000mL/24h with diuretics) and creatinine clearance (>20mL/min) occurred.
If cessation criteria were not fulfilled after 7 days, conversion to intermittent hemodialysis would be considered.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Early RRT group | Experimental | Other: Renal replacement therapyPatients who will undergo renal replacement therapy (RRT) within 6 hours of diagnosis of stage 2 acute kidney injury (AKI). |
| Delayed RRT group | Active comparator | Other: Best medical managementPatients who will undergo renal replacement therapy (RRT) if one of the absolute indications for RRT is present. |
Who may qualify
- Ages
- 19 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Patients within 7 days after cardiac surgery
- Acute kidney injury (AKI) described as Kidney Disease: Improving Global Outcomes (KDIGO) stage 2 (urine output <0.5mL/kg/h for ≥6h or 2-fold increase in serum creatinine compared with baseline)
Key exclusion criteria (3 listed)
- previous renal replacement therapy
- AKI secondary to obstructive nephropathy
- previous kidney transplantation
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Renal replacement therapyContinuous renal replacement therapy using continuous venovenous hemodiafiltration (CVVHDF) | Other | Early RRT group |
| Best medical managementThe best medical management continues until the patient meets absolute indication of renal replacement therapy | Other | Delayed RRT group |
Primary outcome
Number of participants with operative mortality
Time frame: at postoperative 30 days
any death, regardless of cause, occurring (1) within 30 days after surgery in or out of the hospital, and (2) after 30 days during the same hospitalization subsequent to the operation
8 secondary outcomes
Overall survival
Time frame: at postoperative 90 days
Number of participants with cardiovascular mortality
Time frame: at postoperative 90 days
Number of participants with renal replacement therapy dependency
Time frame: at postoperative 90 days
Number of participants with major adverse kidney events (MAKE)
Time frame: at postoperative 90 days
Number of participants with renal replacement therapy related morbidity
Time frame: at postoperative 90 days
Duration of mechanical ventilation
Time frame: at postoperative 30 days
Duration of intensive care unit stay
Time frame: at postoperative 30 days
Hospital length of stay
Time frame: at postoperative 30 days
Results and safety
The study was stopped early (reason given: This multicenter randomized controlled trial planned competitive enrollment across multiple sites; however, no patients were enrolled at one site. Only 44 of 202 participants were enrolled over four years, so early termination is proposed.). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Feb 2026.
- Individual participant dataSharing planned: No. IPD will not be shared because it is not allowed by our institutional IRB.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ho Young Hwang, MD, PhD principal investigator
Seoul National University Hospital
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Renal replacement therapy and Best medical management in people with Acute Kidney Injury, run by Seoul National University Hospital at 2 sites in South Korea.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 12 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in South Korea. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was stopped early (reason given: This multicenter randomized controlled trial planned competitive enrollment across multiple sites; however, no patients were enrolled at one site. Only 44 of 202 participants were enrolled over four years, so early termination is proposed.). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of participants with operative mortality (time frame: at postoperative 30 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Feb 2026.