Early RRT in AKI After Cardiac Surgery

NCT ID: NCT05175053

Last Updated: 2025-05-29

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 202 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2021-12-24
• Study Completion Date: 2028-09-30

Brief 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 (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.

Conditions

Acute Kidney Injury

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Early RRT group

Patients who will undergo renal replacement therapy (RRT) within 6 hours of diagnosis of stage 2 acute kidney injury (AKI).

Group Type: EXPERIMENTAL

Renal replacement therapy

Intervention Type: OTHER

Continuous renal replacement therapy using continuous venovenous hemodiafiltration (CVVHDF)

Delayed RRT group

Patients who will undergo renal replacement therapy (RRT) if one of the absolute indications for RRT is present.

Group Type: ACTIVE_COMPARATOR

Best medical management

Intervention Type: OTHER

The best medical management continues until the patient meets absolute indication of renal replacement therapy

Interventions

Renal replacement therapy

Continuous renal replacement therapy using continuous venovenous hemodiafiltration (CVVHDF)

Intervention Type: OTHER

Best medical management

The best medical management continues until the patient meets absolute indication of renal replacement therapy

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• 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)

Exclusion Criteria

• previous renal replacement therapy
• AKI secondary to obstructive nephropathy
• previous kidney transplantation

• Minimum Eligible Age: 19 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Seoul National University Bundang Hospital

OTHER

Sponsor Role: collaborator

Seoul National University Hospital

OTHER

Sponsor Role: lead

Responsible Party

Ho Young Hwang

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Ho Young Hwang, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Seoul National University Hospital

Locations

Seoul National University Bundang Hospital

Seongnam, , South Korea

Site Status: RECRUITING

Seoul National University Hospital

Seoul, , South Korea

Site Status: RECRUITING

Countries

South Korea

Central Contacts

Ho Young Hwang, MD, PhD

Role: CONTACT

scalpel@hanmail.net

82-2-2072-3020

Sue Hyun Kim, MD

Role: CONTACT

annesue01@gmail.com

82-2-2072-0358

Facility Contacts

Dong Jung Kim, MD

Role: primary

mdknockout@gmail.com

82-31-787-7139

Ho Young Hwang, MD, PhD

Role: primary

scalpel@hanmail.net

82-2-2072-3020

Sue Hyun Kim, MD

Role: backup

annesue01@gmail.com

82-2-2072-0358

Other Identifiers

D-2107-213-1239

Identifier Type: -

Identifier Source: org_study_id