Coagulation and fibrinolysis system in aortic surgery under deep hypothermic circulatory arrest with aprotinin - The importance of adequate heparinization

Background Coagulation and fibrinolysis parameters were compared between two strategies of heparinization during cardiopulmonary bypass (CPB) in patients who underwent aortic surgery with deep hypothermic circulatory arrest (DHCA) and retrograde cerebral perfusion (RGCP) with aprotinin. Methods and Results From January 1993 to January 1996, 94 patients underwent aortic surgery with DHCA with aprotinin; replacement of the ascending aorta took place in 14 patients, arch in 69, and descending aorta in 11. Two million units of aprotinin was administrated in the priming of CPB, and 3 mg/kg heparin was given before CPB. During CPB, 49 patients had an additional 1 mg/kg/h heparin regardless of activated clotting time (ACT) [group A], whereas 45 patients had an additional 1 mg/kg/h heparin when ACT was less than 500 seconds [group B]. ACT, PT, aPTT, fibrinogen, AT-3, plasminogen, alpha 2-PI (plasmin inhibitor), fibrin/fibrinogen degradation products (FDP), DD (D dimer), TAT (thrombin-antithrombin complex), PIC (plasmin-plasmin inhibitor complex), beta-TG (thromboglobulin), and PF-4 (platelet factor-4) were assayed. No difference was detected between the two groups regarding the duration of operation, CPB, aortic cross-clamping, DHCA, RGCP, and time from the end of CPB to admission to ICU. The heparin dose was greater in group A, but the protamine dose was similar. There was no difference in bleeding after perfusion or in ICU. Levels of TAT, fibrinogen, and DD were lower in group A. PIC, alpha-PI, and FDP value showed no difference. PF-4 and beta-TG were lower in group A, and the platelet count at the end of operation and the day after the operation was higher in group A. Conclusions Platelets were better preserved and activation of the coagulation system during CPB was less seven in patients who had a regular additional constant heparin regimen irrespective of ACT in surgery for the aortic aneurysm with DHCA and aprotinin usage. An accurate monitoring system for heparinization is necessary to maintain appropriate anticoagulation during CPB in patients who are undergoing aortic surgery with DHCA using aprotinin.