Safety of a Restrictive versus Liberal Approach to Red Blood Cell Transfusion on the Outcome of AKI in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial

Abstract

BackgroundSafely reducing red blood cell transfusions can prevent transfusion-related adverse effects, conserve the blood supply, and reduce health care costs. Both anemia and red blood cell transfusion are independently associated with AKI, but observational data are insufficient to determine whether a restrictive approach to transfusion can be used without increasing AKI risk.MethodsIn a prespecified kidney substudy of a randomized noninferiority trial, we compared a restrictive threshold for red blood cell transfusion (transfuse if hemoglobin<7.5 g/dl, intraoperatively and postoperatively) with a liberal threshold (transfuse if hemoglobin<9.5 g/dl in the operating room or intensive care unit, or if hemoglobin<8.5 g/dl on the nonintensive care ward). We studied 4531 patients undergoing cardiac surgery with cardiopulmonary bypass who had a moderate-to-high risk of perioperative death. The substudy’s primary outcome was AKI, defined as a postoperative increase in serum creatinine of ≥0.3 mg/dl within 48 hours of surgery, or ≥50% within 7 days of surgery.ResultsPatients in the restrictive-threshold group received significantly fewer transfusions than patients in the liberal-threshold group (1.8 versus 2.9 on average, or 38% fewer transfusions in the restricted-threshold group compared with the liberal-threshold group; P<0.001). AKI occurred in 27.7% of patients in the restrictive-threshold group (624 of 2251) and in 27.9% of patients in the liberal-threshold group (636 of 2280). Similarly, among patients with preoperative CKD, AKI occurred in 33.6% of patients in the restrictive-threshold group (258 of 767) and in 32.5% of patients in the liberal-threshold group (252 of 775).ConclusionsAmong patients undergoing cardiac surgery, a restrictive transfusion approach resulted in fewer red blood cell transfusions without increasing the risk of AKI.

Association between transfusion of blood products and acute kidney injury following cardiac surgery

“…In the present study, AKI occurred in 27.7% of the 1960 patients included and the need for renal replacement therapy was 2.8%, similar to previous studies using the same KDIGO classification 2,24‐26 . RBC, FFP and platelet transfusion were all associated with an increased risk of more severe stages of AKI in the univariate analysis in a dose‐dependent manner.…”

“…In light of the dose‐dependent hazard, a potential strategy for reducing amount of transfusions is to lower the threshold for RBC transfusions. Recently, a sub‐study from the TRICS‐III trial showed that a restrictive approach to RBC transfusion was non‐inferior to a liberal strategy in terms of AKI development 24 . However, even though the amount of RBC transfusions was significantly higher in the liberal group over a 7 days observation period, the intraoperative nadir haemoglobin levels were comparable in the two intervention groups.…”

Influence of blood haemoglobin concentration on renal haemodynamics and oxygenation during experimental cardiopulmonary bypass in sheep

“…A similar conclusion was drawn after follow‐up of these patients 6 months after their operation 28 . Importantly, in a pre‐specified sub‐study of TRICS III, 29 no difference in the incidence of post‐operative AKI was found between the restrictive and liberal thresholds 30 . It is plausible that the lack of a reduction in the incidence of AKI when a more liberal transfusion threshold was used is at least partly attributable to the absence of a clinically significant impact of intra‐operative blood transfusion on intraoperative renal medullary tissue hypoxia.…”

The Incidence, Risk Factors and In-Hospital Mortality of Acute Kidney Injury in Patients After Surgery for Acute Type A Aortic Dissection: A Single-Center Retrospective Analysis of 335 Patients

“…Previous studies have also found red blood cell transfusion to be an independent risk factor for post-operative AKI (8,23). In a recent randomized clinical trial, Garg et al (33) demonstrated that a restrictive transfusion approach can reduce red blood cell transfusions in cardiac surgery without increasing the risk of AKI compared with a liberal transfusion approach. Although the causal relationship between red blood cell transfusion and AKI was not directly established in this relatively large-sample research, it seems that unnecessary red blood cell transfusions do not confer any additional benefit.…”