Few clinical studies have attempted to elucidate the risk : benefit ratio of anaemia and transfusion in cardiac patients. Two small RCTs [62, 72] examined transfusion practice in patients undergoing coronary artery bypass grafting, and concluded that a conservative approach to the administration of RBCs may be safe. However, two recent cohort studies suggested that anaemia may increase the risk of mortality in critical illness [73] and following surgery in patients with cardiovascular disease [74] . There were 418 and 420 patients in the restrictive and liberal transfusion groups, respectively. *Difference calculated by subtracting mean values of restrictive group from those of liberal group. † Three patients were lost to 60-day mortality rate; therefore n = 835. ‡ Nonsurvivors are considered to have all organs failing on date of death. § Changes in MOD score from baseline, while also incorporating adjustment for death. Data from Hébert et al [10] .