Commentary: Come in from the cold

Abstract

Perioperative bleeding is a recognized complication of cardiac procedures, with increased risks associated with cases performed on cardiopulmonary bypass and those requiring hypothermia. This complication is further compounded by evidence demonstrating that blood transfusions negatively impact both short-and long-term morbidity and mortality. [1][2][3][4] Sultan and colleagues 5 have reported their institution's experience with blood product use in aortic surgery and resultant postoperative outcomes. Although this study is not the first to evaluate this issue, it is one of the largest to date, with the authors assessing 824 patients undergoing aortic surgery requiring circulatory arrest and comparing propensity-matched cohorts separated based on the need for transfusion. Ultimately, the authors found that longer procedure times and greater surgical complexity corresponded with increased blood component transfusions, with greater mortality rates demonstrated in those receiving transfusions. Although it is generally accepted that aortic procedures associated with deep hypothermic circulatory arrest (DHCA) often use more blood products, Sultan and colleagues suggest that DHCA coupled with blood component transfusion results in significantly worse outcomes.The hemostatic system functions optimally at normothermia (ie, 37 C), with alterations in the function of pro-and anticoagulant proteins, pro-and antifibrinolytics proteins, and platelets at progressively lower temperatures. 6-8 Accordingly, the temperature associated with DHCA is frequently among the usual suspects blamed for coagulopathy and the resultant postoperative bleeding.