Shed blood autotransfusion influences ischemia-sensitive laboratory parameters after coronary operations

The diagnostic significance of ischemia-sensitive laboratory parameters in respect to possible interference with shed blood autotransfusion was assessed in a prospective study with 100 patients undergoing elective coronary artery bypass grafting. Serum levels of creatine kinase, creatine kinase MB activity, creatine kinase MB mass concentration, 2-hydroxybutyrate dehydrogenase, lactate dehydrogenase-1, troponin-T, myoglobin, and glutamicoxaloacetic transaminase were repeatedly assessed up to the sixth postoperative day. Thirty-seven patients were excluded from the study due to postoperative development of myocardial infarction (n = 4), transient ischemic events (n = 25), and left bundle-branch blocks (n = 8). In the remaining group of 63, 37 patients were retransfused with 580 +/- 370 mL shed blood up to the twelfth postoperative hour, and 26 patients did not receive autotransfusion due to minimal mediastinal blood loss. The results of our study show that the ischemia-sensitive laboratory parameters were significantly influenced by shed blood autotransfusion: 8 hours postoperatively, creatine kinase (272%), creatine kinase MB fraction (151%), 2-hydroxybutyrate dehydrogenase (130%), lactate dehydrogenase-1 (133%), troponin-T (200%), myoglobin (159%) and glutamic-oxaloacetic transaminase levels (153%) were significantly elevated (p < 0.05) in patients with postoperative autotransfusion, although there were no electrocardiographic signs of myocardial ischemia in this group of patients. Our study shows that postoperative autotransfusion of mediastinal shed blood may interfere with the diagnosis of perioperative myocardial ischemia by laboratory parameters in coronary bypass patients.