Effect of autotransfusion on fibrinolysis in open heart patients

Autotransfused blood is often used as an alternative to banked blood. The fibrinolytic consequences of autotransfused blood are undefined. This prospective study was designed to determine the effect of intraoperative autotransfused blood on fibrinolysis and other coagulation parameters. Ten consecutive patients undergoing cardiopulmonary bypass (CPB) for open-heart procedures were studied. All patients received autotransfused blood intraoperatively and tolerated the procedure. Blood samples were taken preoperatively, intraoperatively, and at 6, 12, and 24 hours postoperatively. Coagulation parameters including prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen, fibrin degradation products, and D-dimer levels were measured at each time point. In addition, the quantity of autotransfused blood and additional standard blood products were recorded. Nonparametric repeated measures analyses with post hoc tests adjusted using the Bonferroni correction were used to analyze the data. Mean PT increased from 13.9 +/- 3.0 seconds preoperatively to 15.7 +/- 1.6 seconds intraoperatively, but then gradually declined to 14.5 +/- 1.1 seconds 24 hours postoperatively. A similar temporal pattern was observed for PTT, which reached a peak of 55.7 +/- 33.0 seconds intraoperatively from a preoperative baseline of 44.0 +/- 15.3 seconds. Adjusted post hoc comparisons of fibrinogen levels indicated a statistically significant difference between preoperative and 6 hour postoperative medians, (p < .0083). Fibrin degradation products had a modest and nonsignificant decrease over the 24-hour study period, (from 12.6 +/- 6.7 mcg/mL preoperatively to 9.0 +/- 1.6 mcg/ml 24 hours postoperatively), while D-dimer levels rose from a baseline of 0.54 +/- 0.09 mcg/mL to 0.98 +/- 0.48 mcg/mL 6 hours postoperatively, but declined nearly to baseline by 24 hours postoperatively, (0.62 +/- 0.11 mcg/mL). We conclude that although autotransfused blood may activate the fibrinolytic pathway, its use remains safe and does not require the use of additional banked blood products.