This is a small observational single center study (n = 76), but covering 12 years (between May 1995 and November 2006), that shows some excellent results: a significant reduction of allogeneic packed red cell blood transfusion (53% vs. 15%; p = 0.001) and of allogeneic fresh frozen plasma (61% vs. 22%; p = 0.002). While few patients could donate (n = 27), the study was conducted without any complications and the donation and transfusion protocols were well established. Unfortunately, no details are presented regarding the use of tranexamic acid, aprotinin, erythropoietin, iron, cell savers, postoperative recovery devices or any other blood saving measure. Similarly, no details are presented on the number of blood units donated which ranged between one to three and the associated outcomes. Although there were statistically significant differences between both groups (homograft exchange and much longer pump time), the logistic regression analysis identified only “no-autologous blood predonation” (OR 5.4, 95%CI 1.7-17.7; p = 0.005) and “time on extracorporeal circulation > 83 minutes” (OR 5.0, 95%CI 1.5-16.8; p = 0.009) to be predictive for allogeneic blood transfusion. I encourage the authors to develop a RCT using only two donated units (probably the most cost-effective approach) but fresher autologous blood (less than 21 days).
In my modest opinion, with a Delphi methodology, this is a III level study with a D recommendation, but with the GRADE methodology, the recommendation could move up to a 1C recommendation (“observational study, in which benefits clearly outweigh risk, achieving strong recommendation but may change when higher-quality evidence becomes available”). This study will change my routine practice.
– Jos Antonio Garcia-Erce