Postperfusion syndrome is still a problem in long cardiac operations using extracorporeal circulation (ECC). To evaluate whether or not centrifugal blood pumping during open heart surgery is beneficial, a randomized, prospective study was undertaken of 50 consecutive patients undergoing elective coronary artery bypass grafting. The patients were divided into two groups of 25 each. In group 1 a centrifugal pump (Biomedicus) was used as arterial blood pump, while in group 2 a roller pump (Stöckert) was used. The two groups did not differ significantly and the number of variables during surgery was kept low (identical perfusion set, two surgeons, minimal cardiotomy suction). The parameters studied included the cellular elements of the blood and components indicating their functional integrity, such as PMN-elastase, plasma hemoglobin, beta-thromboglobulin, and thrombin-antithrombin III complex and D-dimer as representatives for activated coagulation and secondary fibrinolysis. Blood and urine samples were taken every 15 min during ECC, on arrival in the intensive care unit, and 1, 3, 6, 12, and 24 h thereafter. No difference between the groups was found in regard to bypass time, ECC flow and volume, fluid balance, and clinical outcome. Significant differences in favor of group 1 were found in plasma hemoglobin (P less than 0.05), beta-thromboglobulin (P less than 0.01), D-dimer (P less than 0.05), and platelet counts (P less than 0.5). These differences were clearly ECC-time-dependent and became statistically significant after 90 min bypass. We conclude that roller pumps still can be safely used for standard cardiac procedures.(ABSTRACT TRUNCATED AT 250 WORDS)