INTRODUCTION

Today, cardiovascular diseases, such as coronary heart disease, are a leading cause of death worldwide. Coronary artery bypass grafting (CABG) is a standard of care for those with coronary artery disease^[1]. Improvements in cardiopulmonary bypass (CPB) have enabled significant advances in cardiac surgery. CPB provides a bloodless field in cardiac surgery and is a necessary treatment modality in some cases. Despite the fact that the use of the CPB system facilitates surgery, it carries various risks^[2]. While surgical techniques have improved with CPB, it is important to manage associated risks, including coagulopathic bleeding, which poses a significant risk during weaning from CPB and is associated with poor outcomes and mortality in cardiac surgery patients^[3].

The use of antifibrinolytics has been shown to reduce blood loss and subsequent transfusions, which are associated with major morbidity and mortality, in various surgical procedures such as cardiac surgery, trauma, orthopedic surgery, liver surgery and solid organ transplantation, obstetrics and gynecology, neurosurgery, and non-surgical diseases. The amount of evidence supporting the effectiveness of tranexamic acid (TXA), a synthetic lysine analog, has grown over time. It was first patented in 1957, and its use has gradually increased over the years^[4].

TXA has gained significant attention due to its potential to reduce morbidity and mortality in surgical and traumatic bleeding. Studies have shown that it can reduce mortality from traumatic bleeding by one-third without causing significant safety concerns. In patients with surgical bleeding that require transfusions, intravenous TXA has been shown to reduce blood loss. It can also be used topically to reduce bleeding. Its efficacy is being further investigated in large pragmatic studies regarding traumatic head injuries, postpartum hemorrhage, and upper gastrointestinal bleeding. Adverse effects of TXA, which interfere with cerebral gamma aminobutyric acid and glycine receptors, are rare, except at high doses where neurological events have been recorded. Furthermore, clinical studies indicate that using a higher dose does not increase efficacy; namely, a dose of 1 g of TXA administered intravenously to an adult patient has maximum efficacy without increasing adverse effects^[5].

TXA provides a beneficial treatment for bleeding in tissues rich in plasminogen activators or under endocrine influences, as well as in cases where there is a risk of secondary hemorrhage due to local or generalized primary hyperfibrinolysis following trauma. Additionally, it is used in reducing hyperfibrinolytic bleeding in cardiovascular surgeries and has a dose-independent effect on fibrinolysis parameters. Since its introduction in 1962, TXA has become a major antifibrinolytic agent for managing hemorrhage in patients undergoing cardiac surgery, particularly after the discontinuation of aprotinin in 2007^[6-8].

This prospective study aimed to investigate the efficacy of TXA, a commonly used antifibrinolytic agent, in reducing bleeding for both intraoperative and postoperative hemorrhage. For this purpose, the study compared perioperative bleeding rates between two patient groups - those who received TXA and those who did not - during cardiac surgery with CPB.

METHODS

RESULTS

As seen in Table 1, there were no significant differences with regard to age, sex, height, weight, BSA, flow, and EF percentage between the two groups (P>0.05). As seen in Table 2, the number of CABG performed in the groups was comparable, with no statistically significant difference (P>0.05). Table 3 shows the minimum, maximum, mean, and standard deviation values of the TXA applied group.

Table 1 - Demographic and descriptive data of groups.

Table 2 - Number of CABG performed in groups.

Table 3 - Group 1 - TXA administration data.

As seen in Table 4, there were no significant differences between the groups in terms of total perfusion time, aortic cross-clamping time, preoperative hematocrit, hemoglobin, platelet, and red blood cell levels (P<0.05). Nonetheless, there were significant differences between the groups in terms of intraoperative (through the heart-lung machine) and postoperative red blood cell transfusion rates, intraoperative and postoperative bleeding drainage amounts (Figure 1), and postoperative hematocrit, hemoglobin, platelet, and red blood cell levels (P<0.05).

Table 4 - Comparison of preoperative variables between the groups.

Fig. 1 - Comparison of the drainage amount rates between the groups. TXA=tranexamic acid.

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Fig. 1 - Comparison of the drainage amount rates between the groups. TXA=tranexamic acid.

DISCUSSION

Coronary artery disease is the leading cause of death in developed countries^[1]. CABG operations with CPB remain an important treatment method and sometimes the only method. The aim of this study was to evaluate the efficacy of TXA, a drug commonly used to control bleeding, on the amount of bleeding drainage during and after cardiac surgery. The study revealed that the use of TXA had positive effects on intraoperative and postoperative hematological parameters, reducing blood product use, and the amount of bleeding drainage in patients who underwent CABG with CPB. Besides, demographic data and intraoperative surgical variables, except for the use of TXA, were similar between the groups and did not affect the results.

Rostami et al.^[1] conducted a study to investigate the effect of TXA in reducing postoperative bleeding in patients undergoing CABG. They randomly divided 62 patients into two groups: the TXA group and the control group. After separation from the heart-lung machine, 2 g of TXA was injected locally into the mediastinum in the TXA group, while the control group was given the same amount of normal saline (100 cc). Significant differences were found between the two groups in terms of postoperative bleeding, hematocrit, platelet transfusion, operative time, and fresh frozen plasma received (P=0.0001; P=0.01; P=0.0001; P=0.0001; P=0.0001, respectively), with lower requirements observed in the TXA group^[1]. These results are consistent with our study, which showed that in the TXA group, intraoperative (through the heart-lung machine) and postoperative red blood cell transfusion rates (0.62 ± 0.89 and 0.67 ± 0.828, respectively), and intraoperative and postoperative bleeding drainage amounts (66.37 ± 35.48 and 308.75 ± 132.45, respectively) were lower, and postoperative hematocrit (28.49 ± 4.65), hemoglobin (9.96 ± 1.45), platelet (200.22 ± 59.56), and red blood cell (3.30 ± 0.52) levels were higher.

Similarly, Myles et al.^[9] found that TXA use in patients undergoing coronary artery surgery was associated with a lower risk of bleeding within 30 days of surgery compared to the control group, without an increased risk of death or thrombotic complications. Several other studies have also reported that TXA use reduced postoperative drainage (bleeding)^[10-12]. Chen et al.^[13] reported in their study that TXA use could reduce the requirement for blood products without increasing the risk of postoperative seizures after CPB.

Shi et al.^[14] conducted a study comparing the efficacy and side effects of high-dose and low-dose TXA in patients who underwent cardiac surgery with CPB. The high-dose group received a 30 mg/kg bolus, 2 mg/kg prime, and 16 mg/kg/hour maintenance dose (n=1525), while the low-dose group received a 10 mg/kg bolus, 1 mg/kg prime, and 2 mg/kg/hour maintenance dose (n=1506). The study found no significant difference in the need for red blood cell transfusion and adverse events (30-day mortality, seizures, renal dysfunction, and thrombotic events) between the high-dose and low-dose groups^[14]. Besides, Murkin et al.^[15] reported that high-dose TXA use in cardiac surgery performed with CPB in elderly patients was associated with clinical seizures in susceptible patients^[15]. There are also studies that have reported similar results^[16,17].

In their study, Guo et al.^[18] investigated the efficacy of different TXA regimens in reducing the requirement for transfusion in cardiac surgery. They concluded that TXA was effective in all types of cardiac surgeries, and the low-dose regimen was equally effective in reducing the transfusion rate without increasing the risk of seizures, making it the preferred option^[18]. Similarly, in our study, we also found that low-dose TXA had a significant effect on reducing red blood cell transfusion rates, intraoperative and postoperative bleeding drainage amounts, and improving postoperative hematocrit, hemoglobin, platelet, and red blood cell levels. Therefore, we consider the use of low-dose TXA as a sufficient and effective option.

CONCLUSION

Our study showed that administering TXA during CABG operations with CPB resulted in positive outcomes, including decreased need for RBCS transfusion from the heart-lung machine, reduced amount of intraoperative and postoperative bleeding drainage, and improved postoperative levels of hematocrit, hemoglobin, platelets, and red blood cells. Based on the results of our study, we conclude that the use of TXA has beneficial effects on hematological parameters, reducing blood product use and bleeding drainage in patients undergoing CABG surgery with CPB.