Transfusion requirements after cardiac surgery: the TRACS randomized controlled trial.
Hajjar LA, Vincent JL, Galas FR, Nakamura RE, Silva CM, Santos MH, Fukushima J, Kalil Filho R, Sierra DB, Lopes NH, Mauad T, Roquim AC, Sundin MR, Leão WC, Almeida JP, Pomerantzeff PM, Dallan LO, Jatene FB, Stolf NA, Auler JO Jr.
Perioperative red blood cell transfusion is commonly used to address anemia,
an independent risk factor for morbidity and mortality after cardiac operations;
however, evidence regarding optimal blood transfusion practice in patients undergoing
cardiac surgery is lacking.
Objective To define whether a restrictive perioperative red blood cell transfusion
strategy is as safe as a liberal strategy in patients undergoing elective cardiac surgery.
Design, Setting, and Patients The Transfusion Requirements After Cardiac Surgery
(TRACS) study, a prospective, randomized, controlled clinical noninferiority trial
conducted between February 2009 and February 2010 in an intensive care unit at a
university hospital cardiac surgery referral center in Brazil. Consecutive adult patients
(n=502) who underwent cardiac surgery with cardiopulmonary bypass were eligible;
analysis was by intention-to-treat.
Intervention Patients were randomly assigned to a liberal strategy of blood transfusion
(to maintain a hematocrit30%) or to a restrictive strategy (hematocrit24%).
Main Outcome Measure Composite end point of 30-day all-cause mortality and
severe morbidity (cardiogenic shock, acute respiratory distress syndrome, or acute renal
injury requiring dialysis or hemofiltration) occurring during the hospital stay. The
noninferiority margin was predefined at −8% (ie, 8% minimal clinically important increase
in occurrence of the composite end point).
Results Hemoglobin concentrations were maintained at ameanof 10.5 g/dL(95%confidence
interval [CI], 10.4-10.6) in the liberal-strategy group and 9.1 g/dL (95% CI, 9.0-
9.2) in the restrictive-strategy group (P.001). A total of 198 of 253 patients (78%) in
the liberal-strategy group and 118 of 249 (47%) in the restrictive-strategy group received
a blood transfusion (P.001). Occurrence of the primary end point was similar between
groups (10% liberal vs11%restrictive; between-group difference,1%[95% CI,−6%to
4%]; P=.85). Independent of transfusion strategy, the number of transfused red blood
cell units was an independent risk factor for clinical complications or death at 30 days (hazard
ratio for each additional unit transfused, 1.2 [95% CI, 1.1-1.4]; P=.002).
Conclusion Among patients undergoing cardiac surgery, the use of a restrictive perioperative
transfusion strategy compared with a more liberal strategy resulted in noninferior
rates of the combined outcome of 30-day all-cause mortality and severe morbidity.