Dialectical analysis of heparin residue in perioperative period of off-pump coronary artery bypass grafting

Objective To investigate the best neutralization ratio of protamine and heparin during off-pump coronary artery bypass grafting(OPCABG) by analyzing the advantages and disadvantages of heparin residue after OPCABG. Methods From July 2018 to January 2019, 112 patients undergoing elective OPCABG were included in this study. The patients’ whole blood was drawn at 2 time points, including before entering operating room and entering intensive care unit, to receive thrombelastography(TEG) and heparinase-modified thromboelastography(hmTEG) . Conventional coagulation indexes such as activated coagulation time(ACT) were also detected. All the patients were divided into 3 groups, the non-heparin residue group(30 cases), heparin residue group 1(42 cases) and heparin residue group 2(40 cases) according to the laboratory results of TEG, hmTEG and ACT. We observed the dosage of each group of protamine and heparin, as well as the ratio of heparin and protamine. The changes of R time in TEG and ACT between 3 groups were analyzed and compared. Postoperative chest tube drainage at postoperative 12 h and 48 h, cTnI peak value, incidence of perioperative myocardial infarction(MI), incidence of reoperation and poor wound healing, amount of blood loss and transfusion, and acute renal injury were compared between the 3 groups. Results No significant trio-group differences existed in basic clinical characteristics(all P>0.05). Postoperative R(CKH)time was similar in the 3 groups(P>0.05). Comparing with heparin residue group 1 and heparin residue group 2, the ACT after protamine neutralizing heparin and postoperative R time were decreased, the dosage of protamine, ratio of heparin and protamine, cTnI peak value were increased in the non-heparin residue group(P 0.05). The perioperative myocardial infarction, incidence of reoperation and poor wound healing, postoperative acute renal injury and time of in ICU stay showed no significant differences between the 3 groups(P>0.05). Conclusion Moderate heparin residue after OPCAB suggests that it has myocardial protective effect, and does not significantly increase the risk of bleeding. A large number of heparin residues can affect the coagulation function and lead to bleeding tendency, increase the amount of blood loss and transfusion. It is reasonable to make ACT after protamine neutralize heparin higher than the level of ACT before operation, and not higher than 20% of the level before operation. Key words: Heparin; Protamine; Coronary artery bypass grafting, off-pump; Thromboelastograph