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Kidney Week

Abstract: FR-OR147

Effect of a Restrictive Versus Liberal Approach to Red Blood Cell Transfusion on AKI in Patients Undergoing Cardiac Surgery

Session Information

Category: Acute Kidney Injury

  • No subcategory defined

Authors

  • Garg, Amit X., London Health Sciences Centre, London, Ontario, Canada
  • Mazer, C. David, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada

Group or Team Name

  • TRICS Investigators
Background

Safely reducing red blood cell transfusions avoids transfusion-related adverse effects, conserves the blood supply, and reduces healthcare costs. We conducted a prespecified substudy of the Transfusion Requirements in Cardiac Surgery-III (TRICS-III) trial to determine if a restrictive approach to red blood cell transfusion is as safe as a liberal approach on the risk of acute kidney injury [protocol Can J Kid Health Dis 2018 Jan 3; 5].

Methods

This was a randomized trial of 4531 moderate-to-high–risk patients undergoing cardiac surgery with cardiopulmonary bypass from 73 centers in 19 countries between January 2014 and March 2017. Patients were assigned to a restrictive red blood cell transfusion threshold (transfuse if hemoglobin level was <7.5 g/dL, intraoperatively and postoperatively until day 28 or hospital discharge; n=2251) or a liberal threshold (transfuse if hemoglobin level was <9.5 g/dL in the operating room or intensive care unit, or <8.5 g/dL on the non-intensive care ward; n=2280). Acute kidney injury was defined as an increase in the postoperative serum creatinine concentration (from the preoperative value) of >0.3 mg/dL (≥26.5 μmol/L) within 48 hrs of surgery, or >50% within 7 days of surgery. The prespecified noninferiority margin for the absolute risk difference was 3.5%.

Results

Perioperative acute kidney injury occurred in 27.7% of patients in the restrictive-threshold group and in 27.9% of patients in the liberal-threshold group; absolute risk difference, -0.2% (95% CI, -2.8% to 2.4%). Results were consistent with multiple alternative definitions of acute kidney injury, and in the subgroup with preoperative chronic kidney disease (Table).

Conclusion

A restrictive approach to red blood cell transfusion was as safe as a liberal approach on the risk of acute kidney injury in patients undergoing cardiac surgery. Trial Registration: NCT02042898

 Number of Events (%) 
Restrictive (n=2251)Liberal (n=2280)Risk difference (95% CI)
AKI (primary outcome)624 (27.7%)636 (27.9%)-0.2% (-2.8% to 2.4%)
Alternative Definitions   
AKI or death636 (28.3%)662 (29.0%)-0.8% (-3.4% to 1.9%)
≥ Stage 2 AKI166 (7.4%)150 (6.6%)0.8% (-0.7% to 2.3%)
Stage 3 AKI75 (3.3%)84 (3.7%)-0.4% (-1.4% to 0.7%)
Acute dialysis54 (2.4%)66 (2.9%)-0.5% (-1.4% to 0.4%)
Subgroup   
Chronic Kidney Disease258/767 (33.6%)252/755 (32.5%)1.1% (-3.6% to 5.8%)

AKI=Acute Kidney Injury

Funding

  • Government Support - Non-U.S.