[Influence of preoperative treatment with aspirin or heparin on platelet function and intensity of postoperative bleeding in early period after coronary artery bypass surgery].

Objective: The aim of the study was to evaluate influence of preoperative treatment with aspirin or heparin on platelet function and intensity of postoperative blood loss in early period after coronary artery bypass grafting (CABG).

Material And Methods: Study involved 75 patients (men) with ischemic heart disease, who underwent CABG. Patients were divided into three groups: aspirin pretreated (I group, n=25), heparin pretreated (II group, n=22) and III group (n=28) had no antiplatelet or anticoagulant pretreatment. At 24 h after surgery all patients started treatment with aspirin (ASS 100, Bayer), which lasted all hospitalization period. We have evaluated preoperative coagulation parameters: activated partial thromboplastin time, international normalized ratio, and fibrinogen level. Also we have compared platelet count, platelet aggregation induced by adenosine diphosphate during preoperative period, at 1 h, 20 h and at 7 day after surgery.

Results: Preoperative coagulation parameters were comparable in all groups. Platelet count was also similar. One hour after surgery platelet count remarkably decreased in all groups (p<0.001); at 20 hours after surgery changes remained the same and at 7 day a significant increase was observed in all groups (p<0.001). The lowest rate of preoperative platelet aggregation was found in I group (p<0.05). At 1 hour after surgery platelet aggregation decreased significantly in all groups, particularly in III group (p<0.001). At 20 hours after surgery platelet aggregation had a tendency to reach previous level and increased substantially in all groups. We have found more than 10% increase in platelet aggregation at 7 day compared to 20 hours postoperatively. These changes were observed in 32% (p<0.05), 27.3% (p<0.05) and 35.7% (p<0.001) of patients in the group I, II and III, respectively. Postoperative blood loss was significantly lowest in II group (p<0.01).

Conclusions: Our investigation shows that preoperative treatment with aspirin or heparin had no remarkable influence on dynamics of platelet function in early period after CABG. The least blood loss was observed in patients with heparin pretreatment.