Background The efficacy of tranexamic acid (TXA) to reduce perioperative blood loss and allogeneic blood transfusion in cardiac surgeries has been proved in previous studies, but its adverse effects especially seizure has always been a problem of concern. This meta-analysis aims to provide information on the optimal dosage and delivery method which is effective with the least adverse outcomes. Methods We searched Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE for all relevant articles published before 2018/12/31. Inclusion criteria were adult patients undergoing elective heart surgeries, and only randomized control trials comparing TXA with placebo were considered. Two authors independently assessed trial quality and extracted relevant data. Results We included 49 studies with 10,591 patients into analysis. TXA significantly reduced transfusion rate (RR 0.71, 95% CI 0.65 to 0.78, P<0.00001). The overall transfusion rate was 35%(1573/4477) for patients using TXA and 49%(2190/4408) for patients in the control group. Peri-operative blood loss (MD − 246.98 ml, 95% CI − 287.89 to − 206.06 ml, P<0.00001) and re-operation rate (RR 0.62, 95% CI 0.49 to 0.79, P<0.0001) were also reduced significantly. TXA usage did not increase risk of mortality, myocardial infarction, stroke, pulmonary embolism and renal dysfunction, but was associated with a significantly increase in seizure attack (RR 3.21, 95% CI 1.04 to 9.90, P = 0.04).The overall rate of seizure attack was 0.62%(21/3378) for patients using TXA and 0.15%(5/3406) for patients in the control group. In subgroup analysis, TXA was effective for both on-pump and off-pump surgeries. Topical application didn’t reduce the need for transfusion requirement, while intravenous delivery no matter as bolus injection alone or bolus plus continuous infusion were effective. Intravenous high-dose TXA didn’t further decrease transfusion rate compared with low-dose regimen, and increased the risk of seizure by 4.83 times. No patients in the low-dose group had seizure attack. Conclusions TXA was effective in reducing transfusion requirement in all kinds of cardiac surgeries. Low-dose intravenous infusion was the most preferable delivery method which was as effective as high-dose regimen in reducing transfusion rate without increasing the risk of seizure. Electronic supplementary material The online version of this article (10.1186/s12871-019-0772-0) contains supplementary material, which is available to authorized users.

Summary Aims Safety evaluations of tranexamic acid (TXA) remain sparse, especially with respect to its impact on long‐term outcomes in patients undergoing on‐pump coronary artery bypass grafting (CABG). We hypothesized that the effects of TXA on perioperative bleeding and allogeneic transfusion and its impact on long‐term clinical outcomes of patients receiving on‐pump CABG are superior to those in the control group. Methods In this prospective, randomized, placebo‐controlled trial, 210 patients undergoing primary and isolated on‐pump CABG were randomly assigned to receive TXA or a corresponding volume of saline solution. Randomly assigned patients were followed up at 1, 3, 5, and 7 years after hospital discharge. Finally, 163 patients fulfilled the 7‐year follow‐up. The primary outcome was allogeneic red blood cell (RBC) transfusion. Long‐term mortality and morbidity were also evaluated. Results Compared with placebo, TXA reduced the allogeneic RBC requirement in terms of the volume transfused (4.20 ± 4.06 vs 6.25 ± 4.86 units; P < 0.01), ratio exposed (52.0% vs 71.6%; P < 0.01), and blood loss volume (879.0 ± 392.5 vs 1154.0 ± 582.8 mL; P < 0.01). Except for myocardial infarction, there were no significant differences in mortality or morbidity between the two groups during the 7‐year follow‐up. The TXA group had a lower rate of myocardial infarction than did the placebo group (0.0% vs 4.9% at 84 months; P = 0.03). Conclusions Tranexamic acid significantly decreased postoperative bleeding and allogeneic transfusion in patients undergoing on‐pump CABG. The 7‐year follow‐up suggested that the use of TXA was safe and might play a potential role in the prevention of long‐term myocardial infarction.

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IntroductionPerioperative coagulopathy is common in patients undergoing aortic surgery, increasing the risk of excessive blood loss and subsequent allogeneic transfusion. Blood conservation has become a vital part of cardiovascular surgery, but measures to protect platelets from destruction by cardiopulmonary bypass (CPB) are still lacking. Autologous platelet concentrate (APC) may have potential benefits for intraoperative blood preservation, but its efficacy has not been studied extensively. This study aims to evaluate the efficacy of APC as a blood conservation technique to reduce blood transfusion in adult aortic surgery.Methods and analysisThis is a prospective, single-centre, single-blind randomised controlled trial. A total of 344 adult patients undergoing aortic surgery with CPB will be enrolled and randomised to either the APC group or the control group with a 1:1 randomisation ratio. Patients in the APC group will receive autologous plateletpheresis before heparinisation, while those in the control group will not. The primary outcome is the perioperative packed red blood cell (pRBC) transfusion rate. Secondary endpoints include the volume of perioperative pRBC transfusion; drainage volume within 72 hours post-surgery; postoperative coagulation and platelet function; and the incidence of adverse events. Data will be analysed according to the intention-to-treat principle.Ethics and disseminationThis study was approved by the institutional review board of Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College (no. 2022-1806). All procedures included in this study will be performed in adherence to the Helsinki Declaration. The results of the trial will be published in an international peer-reviewed journal.Trial registration numberChinese Clinical Trial Register (ChiCTR2200065834).