RETRACTED: INFLUENCE OF DIFFERENT ANTICOAGULATION REGIMENS ON PLATELET-FUNCTION DURING CARDIAC-SURGERY (Retracted article. See vol. 125, pg. 414, 2020)

Qualitative platelet defects are of great importance as a cause of bleeding in cardiac surgery. We have studied the effects of different anticoagulation regimens on platelet function in 60 patients undergoing elective aorto-coronary bypass grafting with cardiopulmonary bypass (CPB). Patients were allocated randomly to four groups (each group n = 15) to receive either: bovine heparin 300 u. kg(-1) (standard); heparin 300 u. kg(-1) followed by a continuous infusion of 10000 u. kg(-1) until the end of CPB; heparin 600 u. kg(-1); or heparin 600 u. kg(-1) in addition to high-dose aprotinin 2 million iu before CPB, 500000 iu h(-1) until the end of operation and 2 million iu added to the prime. Platelet function was evaluated by aggregometry (turbidometric technique) using adenosine triphosphate (ADP) 2.0 mu mol litre(-1), collagen adrenaline 25 mu mol litre(-1) and saline solution (control) as inducers. Both maximum aggregation and maximum gradient of aggregation were measured in arterial blood samples before, during and after CPB until the first day after operation. Mean total dose of heparin given in groups 2, 3 and 4 was more than 50000 u. and differed significantly from that of group 1 (28150 (SD 4700) u.). Platelet aggregation variables were most depressed during CPB and until the end of surgery in groups 2 and 3 (maximum aggregation - 54% to - 75% of baseline values). In the postoperative period, platelet function recovered but did not completely reach baseline values in these patients. Blood loss and the use of homologous blood and blood products were also highest in these high-dose heparin groups. The addition of aprotinin (group 4) prevented the effects of high-dose heparin on platelet aggregation. Bleeding was also significantly less than in the other high-dose heparin groups but did not differ from the standard heparin regimen. We conclude that high-dose heparin, whether given as a single dose or administered continuously, adversely affected platelet function and aprotinin prevented these adverse effects on platelet aggregation.