Low dose systemic heparinization combined with heparin-coated extracorporeal circulation - Effects related to platelets

Background. A heparin coated cardiopulmonary bypass system combined with fu ll and low dose systemic heparinization in coronary bypass surgery was inve stigated in a prospective, randomised study. Roller pumps, coronary suction and an open cardiotomy reservoir were used. Methods. One hundred and nineteen patients were divided into 3 groups: grou p A (n=39) had a standard uncoated extracorporeal circulation (ECC)-set and systemic heparin was given in an initial dose of 400 IE/kg body weight. Du ring ECC activated clotting time (ACT) was kept at greater than or equal to 480 sec. Group B (n=42) had the same ECC-set completely coated with low mo lecular weight heparin, i.v. heparin was administered in the same dose as i n group A, ACT was again kept at greater than or equal to 480 sec. Group C (n=38) had the same coated ECC set as group B, but ix. heparin was reduced to 150 IE/kg and during ECC ACT was maintained of greater than or equal to 240 sec. Results. Platelet decrease was significantly less in both groups utilizing coated circuitry as compared to control group A. Activation of thrombocytes as marked by beta -thromboglobulin (not PF4) was significantly decreased i n patients treated with coated circuits combined with low dose systemic hep arinization and postoperative bleeding was significantly reduced. Conclusions. We conclude that in heparin coated extracorporeal circulation combined with either full dose or reduced systemic heparinization compared to uncoated circuits platelet count reduction is significantly less. Platel et activation as marked by beta -thromboglobulin and postoperative blood lo ss are decreased with coated equipment and low i.v. heparinization.