Thromboelastographic Analysis of the Coagulation System During Cardiopulmonary Bypass: Analysis of the Effect of Low-Dose Aprotinin

Kim, Kwhan Mien; Park, Kay Hyun; Jun, Tae Gook; Kim, Jhin Gook; Shim, Young Mog; Park, Pyo Won; Chae, Hurn; Kim, Won Gon; Kim, Yong Jin

Abstract

Thromboelastography(TEG) is the unique measure that gives rapid information about the whole clotting process. Simplifying the diagnosis of coagulopathy during operations, TEG can provide an adequate therapy for postoperative bleeding. Remarkable improvement in hemostasis after cardiopulmonary bypass(CPB) has been achieved by the treatment with proteinase inhibitor aprotinin, but the hemostatic mechanism of aprotinin during CPB is still unclear. This study was designed to evaluate the effects of aprotinin on coagulation system during CPB by using TEG. Forty patients who underwent CPB were divided into two groups: aprotinin(2 X 10(6) kallikrein inhibition units, as a single dose into the cardiopulmonary bypass priming solution) treatment group(male 14, female 8, mean age=50.8years) and no aprotinin treatment(control) group(male 10, female 8, mean age=53.4 years). TEG, activated clotting time, prothrombin time, activated partial thromboplastin time, platelet counts, fibrinogen and fibrinogen degradation product(FDP) concentrations were checked before and after CPB(30 minutes after neutralization of heparin effect by protamine sulfate). There was no significant difference in other conventional coagulation tests of two groups except postcardiopulmonary bypass FDP concentration in control group, which was significantly increased compared to that in aprotinin group(p<0.05). In TEG variables of both groups, clot formation time(K) and alpha angle(alpha degree) were significantly increased and decreased, respectively, after CPB(p<0.05), but fibrinolytic index(LYS60) was not changed during CPB. In aprotinin group, reaction time(R) was decreased significantly after CPB(p<0.05) but maximum amplitude(MA) was not changed(p>0.05). On the contrary, R was not changed markedly but MA was decreased significantly in control group after CPB(p<0.05). This result shows that the main change in coagulation system during CPB is not hyperfibrinolysis but decrease in clot strength by platelet dysfunction, and the main effect of aprotinin during cardiopulmonary bypass is the maintenance of clot strength to the pre-CPB level by the preservation of platelet function.