To the Editor Significant perioperative bleeding due to cardiac surgery is a common reason for blood transfusions. Smith et al 1 assessed the use of prothrombin complex concentrate (PCC) as an alternative to plasma in patients undergoing cardiac surgery. The authors concluded that PCC seems to be an effective and safe alternative to plasma transfusion, as there was no difference in postoperative bleeding between patients. 1 We would like to praise the authors for conducting the first prospective randomized clinical trial on this topic to our knowledge and would like to know their thoughts on the points we have raised below.In regard to the authors' conclusion that PCC is an effective alternative to plasma transfusion in patients with postcardiopulmonary bypass coagulopathy and bleeding, 1 we wonder if the hemostatic capacity or factors of bleeding patients should have been considered at various time points after intervention to assess the efficacy of PCC compared with plasma in this clinical context. We believe this is an important consideration because a major goal of blood transfusions is to optimize hemostasis postcardiac surgery, so it would be practical to replace all factors lost, which hemostatic tests have suggested that the balance is better achieved with plasma. 2 Although the clinical implications of changes in hemostatic factors have yet to be established in this context, hemostatic factors have variable increases postintervention, 2 which may have the potential to influence the benefits and safety for each intervention in the early postoperative period. Hence, we are curious to know why a detailed hemostatic profile (eg, Factor V, X) of bleeding patients was not assessed. This is particularly important as PCC use in cardiac surgery is becoming increasingly common with variable dosing and a lack of high-quality evidence establishing its superiority. 3 Given that Black patients tend to receive more transfusions (particularly for coronary artery bypass graft) compared with White patients, 4 we question why the study only included 1% Black individuals and 1% Hispanic individuals in the total sample of patients. We wonder if this may have introduced sampling bias and the potential impact on degree of generalizability of their findings. Post-coronary artery bypass graft, Black and Hispanic patients have significantly greater mortality rates, 5 which makes it important to address race and ethnicity in blood transfusion studies.In essence, postcardiopulmonary bypass remains a frequent reason for blood transfusions. 1 We would like to hear the authors' thoughts on considering PCC as an effective alternative to plasma in light of hemostatic profile/factors, as well as racial considerations. We commend the authors on conducting a much-needed study.

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