Advance Targeted Transfusion in Anemic Cardiac Surgical Patients for Kidney Protection

Abstract

Introduction : Acute kidney injury (AKI) is a serious complication of cardiac surgery, and preoperative anemia and perioperative erythrocyte transfusion are important risk factors. Prophylactic erythrocyte transfusion in anemic patients may, therefore, protect against AKI. Methods : In this unblinded, parallel-group, randomized pilot trial, 60 anemic patients (hemoglobin 10-12 g/dL) undergoing cardiac surgery with cardiopulmonary bypass were randomized (1:1) to prophylactic transfusion (2 units of erythrocytes transfused 1 to 2 days before surgery (n = 29) or standard of care (transfusions as indicated; n = 31). Between-group differences in severity of perioperative anemia, transfusion, and AKI (more than 25% drop in estimated glomerular filtration rate) were measured. The relationships between transfusion, iron levels, and AKI were also measured. Results : Perioperative anemia and erythrocyte transfusions were lower in the prophylactic transfusion group--median (25th, 75th percentiles) for nadir hemoglobin was 8.3 (7.9, 9.1) versus 7.6 (6.9, 8.2) g/dL (P = 0.0008) and for transfusion was 0 (0, 2) versus 2 (1, 4) units (P = 0.0002)--but between-group AKI rates were comparable (11 patients per group). In 35 patients with iron studies, perioperative transfusions were directly related to postoperative transferrin saturation (correlation coefficient 0.6; P = 0.0002), and high (more than 80%) transferrin saturation was associated with AKI (5/5 vs. 8/30; P = 0.005), implicating transfusion-related iron overload as a cause of AKI. Conclusions : In anemic patients, prophylactic erythrocyte transfusion reduces perioperative anemia and erythrocyte transfusions, and may reduce plasma iron levels. Adequately powered studies assessing the effect of this intervention on AKI are warranted.

Interrelationship of preoperative anemia, intraoperative anemia, and red blood cell transfusion as potentially modifiable risk factors for acute kidney injury in cardiac surgery: a historical multicentre cohort study

“…45 Other potential options that are currently undergoing evaluation include optimizing oxygen delivery by modifying pump flow; 46 washing of blood to remove the pro-inflammatory molecules, free hemoglobin, and iron that accumulate in the supernatant during storage; 47 haptoglobin therapy to scavenge the free hemoglobin that can be present after CPB and blood transfusion; 48 and prophylactic RBC transfusion one to two days before surgery in patients with preoperative anemia. 49 This latter Relative risks and confidence intervals derived from the Poisson regression model presented in Table 3 and represent each category's adjusted risk of AKI relative to patients who have none of the risk factors approach has been postulated to ''reduce the risk of AKI by reducing the severity of anemia, reducing the need for RBC transfusions, allowing time for the transfused blood to recover from the deleterious changes that they undergo during storage, and allowing time for the kidneys to recuperate from the harmful effects of transfused blood before they are exposed to other renal insults'' during surgery. 49,50 The risk-benefit profiles of these investigational interventions are yet to be determined.…”

“…49 This latter Relative risks and confidence intervals derived from the Poisson regression model presented in Table 3 and represent each category's adjusted risk of AKI relative to patients who have none of the risk factors approach has been postulated to ''reduce the risk of AKI by reducing the severity of anemia, reducing the need for RBC transfusions, allowing time for the transfused blood to recover from the deleterious changes that they undergo during storage, and allowing time for the kidneys to recuperate from the harmful effects of transfused blood before they are exposed to other renal insults'' during surgery. 49,50 The risk-benefit profiles of these investigational interventions are yet to be determined.…”

Indications for red blood cell transfusion in cardiac surgery: a systematic review and meta-analysis

“…The decision to transfuse is complicated by several factors; severe anaemia and excessive blood loss are common in this setting 1,2 , and patients with cardiovascular disease have different transfusion requirements to other patient groups 3 . Transfusion decisions in cardiac surgery are most commonly based on the severity of perioperative anaemia: guidelines currently recommend (Grade C recommendation) highly restrictive transfusion thresholds with Haemoglobin (Hb) concentrations of 6-7g/dL 4,5 .…”

An evidence-based approach to red blood cell transfusions in asymptomatically anaemic patients

“…28 Anaemic patients (Hb 100-120g/l) were either given two units of pRBC 1-2 days prior to surgery (treatment group), or transfused intraoperatively or postoperatively (control group). On average, the treatment group received fewer transfusions during CPB (0 vs 2 units), during surgery (0 vs 2 units) and after surgery (2 vs 4 units).…”