Liberal versus restrictive transfusion strategy for patients with coronary artery disease

Liberal versus restrictive transfusion strategy for patients with coronary artery disease Carson et al 1 reported that the liberal transfusion strategy might improve outcomes and concluded that liberal transfusion strategy was associated with a trend toward fewer major cardiac events and deaths compared with a more restrictive strategy. This study attempted to examine a very relevant question: what should be the ideal transfusion strategy and goal in patients with coronary artery disease? Unfortunately, the study by Carson et al 1 does not answer this question definitively but raises a few important questions regarding utility of this randomized trial: 1. Only 110 patients were finally enrolled, although the initial plan was for enrollment of 200 patients. If approval from the Data Safety Monitoring Committee at the end of 18 months was taken, what are the reasons that investigators gave for early termination? If the reason was the futility or harm of restrictive strategy, how did they justify their call for a large multicenter trial to establish benefit from liberal transfusion? 2. Significant difference in baseline age indicates possibility in error of randomization. 3. The authors state that death was less frequent in liberal arm, whereas in reality, adjusted P for secondary outcomes was .01. Clearly, this is a major methodological mistake, and attempt has been made at showing significance for insignificant results.

In contrast to the results of this trial, another recent randomized controlled trial reported chances of potential harm with liberal transfusion and increase in inhospital death, recurrent myocardial infarction, and new or worsening congestive heart failure. 2 Potential harm of liberal transfusion also was reported in a recent meta-analysis. 3 Am Heart J 2013;166:e25. 0002-8703/$ - see front matter http://dx.doi.org/10.1016/j.ahj.2013.07.021

Partha Sardar, MD Ramez Nairooz, MD Laura Dutu, MD Luciano J. Pastori, MD New York Medical College-Metropolitan Hospital Center, Department of Medicine, New York, NY E-mail: [email protected]

References 1. Carson JL, Brooks MM, Abbott DJ, et al. Liberal versus restrictive transfusion thresholds for patients with symptomatic coronary artery disease. Am Heart J 2013;165(6):964-71. 2. Cooper HA, Rao SV, Greenberg MD, et al. Conservative versus liberal red cell transfusion in acute myocardial infarction (the CRIT Randomized Pilot Study). Am J Cardiol 2011;108(8): 1108-11. 3. Chatterjee S, Wetterslev J, Sharma A, et al. Association of blood transfusion with increased mortality in myocardial infarction: a meta-analysis and diversity-adjusted study sequential analysis. JAMA Intern Med 2013;173(2):132-9.