In their systematic review of the literature, Garfinkle et al. investigate the effects of allogeneic red blood cell transfusion on morbidity (reinfarction, congestive heart failure) and death in patients suffering from acute coronary syndrome (ACS). Included were 11 observational studies with sample sizes ranging from 370 to 85,111 patients. Five studies included more than 10,000 patients each. Follow up ranged from in-hospital to one year post ACS. Transfusion rates ranged from 4 to 30% with the main indication for transfusion being major bleeding.
Transfused patients had a greater risk of reinfarction and congestive heart failure (OR 2.7–8.3). This result persisted after statistical adjustment for potential confounders. Allogeneic red blood cell transfusion at hemoglobin (Hb) concentrations < 8 g/dl decreased the risk of mortality whereas transfusion at Hb concentrations >11 g/dL was associated with a higher mortality. The evidence regarding the use of transfusion at Hb 8-11 g/dL was inconclusive. Major limitations were identified: 1) the observational character of included studies, favoring the possibility of residual confounding, 2) the different state of transfusion safety in the different studies depending on the date of study performance and 3) the inconsistent report of bleeding management.
Nevertheless the authors conclude that the available data support a restrictive transfusion strategy also in patients suffering from ACS.
– Oliver Habler