['According to a recently performed meta-analysis, heparin-bonded circuits do not reduce blood loss in cardiac surgery patients compared to nonheparin-bonded circuits within the first 24 h postoperatively. We investigated the effects of heparin-coated circuits in combination with a reduced systemic heparin dose on early postoperative blood loss (first 12 h), platelet function, and postoperative complications.', 'Patients who underwent their first coronary artery bypass graft surgery were included in a randomized prospective study. Group A (n=149) was perfused with an uncoated extracorporeal circulation (ECC)-set and groups B (n=152) and C (n=149) with heparin-coated ECC-sets. In groups A and B, conventional dose systemic heparin was given, whereas group C received low dose systemic heparin. Blood loss was assessed within the first 12 h postoperatively. Moreover, biochemical parameters of pro-coagulant activity and immunological function were measured.', 'None of the pro-coagulant activity markers and immunological parameters measured differed preoperatively or postoperatively between study groups. However, intraoperative platelet counts and maximal intraoperative concentrations of platelet factor 4, ss-thromboglobulin, and poly-morpho-nuclear (PMN)-elastase were lowest in group C, whereas group C also had the highest concentrations of thrombin-antithrombin complex (P<0.018-0.001). Blood loss within the first 12 h postoperatively was 457 +/- 204 mL in group A, 431 +/- 178 mL in group B, and 382 +/- 188 mL in group C (P<0.01). Complication rates and 30-day mortality did not differ between study groups.'] Does heparin-coated extracorporeal circulation in combination with low dose systemic heparinization reduce early postoperative blood loss in cardiac surgery?