Heparin Independent Coagulation Monitoring during Open Heart Surgery

Woo, Sung; Nho, Joo Seok; Lee, Byung Jun; Hur, Chul Hoae; Kim, Moon Chul; Cho, Kang Hee

Abstract

Thromboelastography(TEG) is a useful monitor for assessing coagulation function in patients undergoing open heart surgery. However, whole blood clotting patterns on TEG are not able to obtain during the cardiopulmonary bypass(CPB) with heparin anticoagulation. When pretreating TEG sample with heparin antidote, heparinase or protamine (heparinase-modified TEG or protamine modified TEG) can make possible assessing the changes of clotting on TEG during the CPB. In this study, data from heparinase(N=50) and protamine(N=26) modified TEG were obtained before, during and after CPB in 76 open cardiac patients, which are presented to describe their usefulness concerning about prediction for coagulation after weaning of CPB. Heparin neutralized TEG revealed that all of depressed values initially after starting bypass were returning back to the values of before starting bypass on weaning CPB. These results suggested that function of the fibrinogen and platelet were relatively well maintained during the bypass. The fibrinolysis during the bypass were commonly developed in 51.2% without affecting by time course of CPB. Even though initial dose of protamine reversal after bypass, there were obviously residual heparin effects on heparinase-modified TEG as simultaneously comparing with native TEG. Regarding correlation of TEG findings in cases excluding fibrinolysis between before and after bypass, R time and MA before bypass were significantly correlate with R time and MA on heparinase-modified TEG after bypass but not on native TEG. (R time: R 0.46, MA: R=0.54). The data gathered in this study suggested heparin independent TEG assay can be useful to assess the coagulation function during the bypass and to predict the values of TEG after bypass, but residual heparin effect must be initially excluded to avoid underestimating the coagulation status after protamine reversal.