Changes in Coagulation and Fibrinolysis Systems During the Perioperative Period of Acute Type A Aortic Dissection
Authors: Zhou Chuzhi , Li Yanzhen , Yan Yalan , Feng Dongjie , Wei Minxin , Wen Junmin 
Published: March 2021

Background: Acute type A aortic dissection (ATAAD) has a high risk of perioperative bleeding and often requires extensive blood product infusions. Analysis of the changes in coagulation and fibrinolysis is both helpful for proper treatment and an improved prognosis. The present study investigated the changes in the coagulation and fibrinolysis systems during the perioperative period of ATAAD.
Methods: Twenty-two patients with ATAAD were included in this study. After diagnosis, all patients underwent ascending aorta replacement, aortic arch replacement, and implantation of a special stented endovascular graft. The control group included 25 patients undergoing elective aortic surgery. Baseline preoperative, intraoperative, and postoperative data were collected in both groups. Venous blood samples of all subjects were collected at five time points, after admission (T1), before surgery (T2), after protamine reversal (T3), postoperative 6 h (T4), and postoperative 24 h (T5), measuring the concentrations of platelet factor 4 (PF4), prothrombin fragment 1 + 2 (F1+2), tissue factor (TF), tissue factor pathway inhibitor (TFPI), plasminogen activator (PA), plasminogen activator inhibitor-1 (PAI-1) and thrombin antithrombin complex (TAT) by enzyme-linked immunosorbent assays (ELISAs).
Results: The average age of the ATAAD group was 49.9±12.5 years old, while that of the control group was 57.0±12.1 years old. There were more patients with a smoking history, and the cardiopulmonary bypass time, aortic cross-clamp time, and preoperative left ventricular ejection fraction were higher in the ATAAD group than in the control group (P < 0.05). Additionally, preoperative fibrin degradation products (FDP) and preoperative D-dimer were higher in the ATAAD group than in the control group (P < 0.05). However, time from onset to operation, intraoperative core temperature, preoperative B-type natriuretic peptide (BNP), and left ventricular end-diastolic diameter in the ATAAD group were lower than those in the control group (P < 0.05). In contrast, however, the proportion of abnormal bicuspid aortic valves in the control group was higher (P < 0.05). TF in the ATAAD group was significantly higher at T1 (7.9±3.7 ng/mL versus 0.9±0.7 ng/mL, P < 0.05). The TFPI in the ATAAD group was higher than that in the control group at T1 and T2 (P < 0.05). Additionally, PA in the ATAAD group was higher than that in the control group at T1, T2, T3, and T5 (P < 0.05), while PA in the control group was significantly higher at T3 than at T1 (P < 0.05). There was no significant difference in PAI-1 between the two groups before surgery (P > 0.05). Nevertheless, both groups reached their peak value at T3. The platelet count and fibrinogen (FBG) in the ATAAD group decreased significantly from T1 to T2 and continued to decrease after cardiopulmonary bypass. F1+2 and TAT in the ATAAD group were higher than in the control group (P < 0.05); however, they peaked at T3. The PF4 in the ATAAD group slightly increased at T1, while PF4 at T3 was significantly higher than at T1 (P < 0.05).
Conclusion: The changes in coagulation and fibrinolysis in the ATAAD group before surgery were very significant, which caused a large amount of fibrinogen and platelet consumption. Cardiopulmonary bypass (CPB) and a lower intraoperative core temperature exacerbated the coagulation and fibrinolysis disorder, and the pro-coagulant function of the platelets was activated after surgery. Maintaining the normal concentration of fibrinogen was helpful to correct the coagulation function disorder.