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Abstract JAMA Transfusion Requirements After Cardiac Surgery: the TRACS Randomized Controlled Trial Ludhmila A. Hajjar, MD, PhD; Jean-Louis Vincent, MD, PhD; Filomena R. B. G. Galas, MD, PhD; Rosana E. Nakamura, MD; Carolina M. P. Silva, MD; Marilia H. Santos, MD, PhD; Julia Fukushima, MSc; Roberto Kalil Filho, MD, PhD; Denise B. Sierra, MD; Neuza H. Lopes, MD, PhD; Thais Mauad, MD, PhD; Aretusa C. Roquim, MD; Marcia R. Sundin, MD; Wanderson C. Leão, MD; Juliano P. Almeida, MD; Pablo M. Pomerantzeff, MD, PhD; Luis O. Dallan, MD, PhD; Fabio B. Jatene, MD, PhD; Noedir A. G. Stolf, MD, PhD; Jose O. C. Auler Jr, MD, PhD Context: 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 hematocrit ≥30%) or to a restrictive strategy (hematocrit ≥24%). 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 a mean of 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 vs 11% 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. Trial Registration: clinicaltrials.gov Identifier: NCT01021631doi:10.1001/jama.2010.1446 In the October 13 issue of JAMA, Hajjar et al and the cardiac surgical group from the University of São Paulo in Brazil report the results of what is almost certainly the first prospective randomized trial to test the hypothesis that a hematocrit value of 24% as a trigger for red blood cell transfusion is not inferior to a trigger of 30% (to convert hematocrit values to a proportion of 1, multiply by 0.01). The target population was all patients undergoing coronary artery bypass, valve surgery, or combined procedures during a 12-month period ending February 2010. The primary outcome was a composite end point that included 30-day mortality and severe morbidity, defined as cardiogenic shock, acute respiratory distress syndrome, or acute renal injury requiring dialysis. In the end, 502 patients were randomized. Postoperatively, the mean hematocrit values were 31.8% (hemoglobin level, 10.5 g/dL [to convert hemoglobin levels to grams per liter, multiply by 10]) in the liberal-strategy group (transfusion trigger, a hematocrit value of 30%) vs 28.4% (hemoglobin level, 9.1 g/dL) in the restrictive-strategy group (transfusion trigger, a hematocrit value of 24%) (P < .001). In the liberal-strategy group, more patients received transfusions (78% vs 47%) and more than twice as much blood was used (613 vs 258 U). There was no difference in the proportion of patients receiving clotting factors. In both cohorts, fresh frozen plasma was given to approximately 25% of patients, platelets to approximately 10%, and cryoprecipitate to 4%. The primary outcomes (death, shock, acute respiratory distress syndrome, and acute renal injury requiring dialysis) were observed in 10% of the liberal-strategy group and 11% of the restrictive-strategy group (P = .85). The authors concluded that the use of a restrictive transfusion policy with a hematocrit value of 24% as the trigger was associated with noninferior rates of mortality and severe morbidity. Equally important was the now-familiar finding that exposure to blood increased the rates of complications irrespective of the transfusion strategy used. For each unit of blood given, the risk of any adverse outcome—including death—appeared to increase by 20% to 28%. This is in concordance with other studies, including the retrospective study by Murphy et al,1 who used propensity matching of close to 9000 patients undergoing cardiac surgery to show that exposure to blood increased the risk of death dramatically. This incremental risk of dying was seen not only in the short term but somewhat unexpectedly in the long term as well. Mortality increased more than 2.5 fold between 30 days and 1 year after surgery, with a 30% increased risk in the ensuing years. In that study, as well as in a 1999 prospective randomized study of critically ill patients undergoing noncardiac surgery by Hébert et al,2 transfusions provided no clinical benefit in patients with hematocrit values as low as 21%. This finding suggests that the restrictive transfusion trigger used in the study by Hajjar et al could have been even more stringent without changing the results. In the same issue of JAMA, Bennett-Guerrero et al3 report the results of an analysis that queried the Society of Thoracic Surgeons Adult Cardiac Surgery Database for the year 2008 to determine transfusion practices throughout the United States in all cardiac surgery programs performing more than 100 on-pump coronary artery bypass graft procedures a year. In this snapshot of current practice, the proportions of patients receiving blood transfusions ranged from 8% to 93%. Although there was no discernable difference in outcomes associated with such widely disparate transfusion rates, the results strongly suggest that the administration of homologous blood to patients undergoing cardiac surgery is not guided by uniform principles and protocols and, in many instances, likely represents a costly and unnecessary use of a scarce resource. The potential to conserve this resource is supported by the data presented by Hajjar et al, which suggest that, by using an even more liberal transfusion trigger than that suggested by the Society of Thoracic Surgery guidelines (a hemoglobin level of 7 g/dL),4 a greater than 50% decrement in blood utilization can be achieved. Back to top Article Information Correspondence: Dr Whitman, Department of Surgery, The Johns Hopkins University, 600 N Wolfe St, Blalock 618, Baltimore, MD 21287 (firstname.lastname@example.org). Author Contributions:Study concept and design: Whitman. Acquisition of data: Whitman. Analysis and interpretation of data: Whitman and DiSesa. Drafting of the manuscript: Whitman and DiSesa. Critical revision of the manuscript for important intellectual content: Whitman and DiSesa. Administrative, technical, and material support: Whitman. Study supervision: Whitman. References 1. Murphy GJReeves BCRogers CARizvi SICulliford LAngelini GD Increased mortality, postoperative morbidity, and cost after red blood cell transfusion in patients having cardiac surgery. Circulation 2007;116 (22) 2544- 2552PubMedGoogle ScholarCrossref 2. Hébert PCWells GBlajchman MA et al. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group, A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. N Engl J Med 1999;340 (6) 409- 417PubMedGoogle ScholarCrossref 3. Bennett-Guerrero EZhao YO’Brien SM et al. Variation in use of blood transfusion in coronary artery bypass graft surgery. JAMA 2010;304 (14) 1568- 1575PubMedGoogle ScholarCrossref 4. Ferraris VAFerraris SPSaha SP et al. Society of Thoracic Surgeons Blood Conservation Guideline Task Force; Society of Cardiovascular Anesthesiologists Special Task Force on Blood Transfusion, Perioperative blood transfusion and blood conservation in cardiac surgery: the Society of Thoracic Surgeons and The Society of Cardiovascular Anesthesiologists clinical practice guideline. Ann Thorac Surg 2007;83 (5) (suppl)S27- S86PubMedGoogle ScholarCrossref
Archives of Surgery – American Medical Association
Published: Apr 1, 2011
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