Valid Comparisons of Antifibrinolytic Agents Used in Cardiac Surgery

Abstract

Bleeding is a major source of morbidity and mortality after cardiac surgical procedures. Patients who return to the operating room for bleeding have a 4-fold increase in mortality and a similar increase in the rate of sternal infection. The significance of this issue is underscored by the fact that patients undergoing cardiac surgery consume up to 30% of the nation’s blood supply. During massive hemorrhage resulting from trauma, the life-saving benefits of blood transfusion are well documented. However, in the more common setting of elective blood and blood component transfusions in intensive care units using arbitrary transfusion triggers, the benefits of transfusion are not well established and may have a net negative influence on outcomes. Indeed, the overt dangers of transfusion are unequivocal (hepatitis C, HIV, fever, infection, increased costs, transfusion reaction), and evidence of the covert dangers of blood transfusion (prolonged intensive care unit stay, increased mortality, increased morbidity) after cardiac surgery is persuasive.1 Because both bleeding itself and the transfusions administered to compensate for blood loss have an untoward impact on outcomes, there is strong motivation to decrease the occurrence of bleeding associated with cardiac surgical procedures in the first place. In this regard, the Society of Thoracic Surgeons Workforce on Evidence Based Surgery, in conjunction with the Society of Cardiovascular Anesthesiologists, recently published a comprehensive guideline outlining appropriate methods for blood conservation in cardiac surgery.2 Article p 2801 Recently, Mangano et al published the short-term3 and longer-term4 results of the same observational study comparing the 3 antifibrinolytic agents available for use in cardiac surgical patients (aprotinin, e-aminocaproic acid [EACA], and tranexamic acid [TXA]) with control patients who received neither of these agents. These studies caused considerable concern among cardiac surgeons and regulatory agencies because the authors concluded that aprotinin was associated with a …