The many roles of tranexamic acid: An overview of the clinical indications for TXA in medical and surgical patients

Clinically significant bleeding can occur as a consequence of surgery, trauma, obstetric complications, anticoagulation, and a wide variety of disorders of hemostasis. As the causes of bleeding are diverse and not always immediately apparent, the availability of a safe, effective, and non-specific hemostatic agent is vital in a wide range of clinical settings, with antifibrinolytic agents often utilized for this purpose. Tranexamic acid (TXA) is one of the most commonly used and widely researched antifibrinolytic agents; its role in postpartum hemorrhage, menorrhagia, trauma-associated hemorrhage, and surgical bleeding has been well defined. However, the utility of TXA goes beyond these common indications, with accumulating data suggesting its ability to reduce bleeding and improve clinical outcomes in the face of many different hemostatic challenges, without a clear increase in thrombotic risk. Herein, we review the literature and provide practical suggestions for clinical use of TXA across a broad spectrum of bleeding disorders.

Topical vs. intravenous administration of tranexamic acid in knee arthroplasty and prevalence of deep venous thrombosis: a randomized clinical trial

Background

Tranexamic acid (TXA) is widely used in orthopedic surgery to reduce perioperative bleeding. Since TXA inhibits fibrinolysis, there is concern that it may increase the risk of thromboembolic events.

Objectives

To verify the prevalence of deep venous thrombosis (DVT) in patients receiving TXA during total knee arthroplasty and to compare topical with intravenous administration of the drug.

Methods

All patients admitted for total knee arthroplasty due to primary arthrosis between June and November of 2014 were recruited consecutively. Thirty patients were randomized to a “topical group” (1.5 g TXA diluted in 50ml saline sprayed over the area operated, before tourniquet release), 30 to an “intravenous group” (20mg/kg TXA in 100 ml of saline, given at the same time as anesthesia), and 30 to a control group (100 ml of saline, given at the same time as anesthesia). All patients had duplex ultrasound scans of the legs on the 15th postoperative day.

Results

Deep venous thrombosis events occurred in five of the 90 patients operated (one out of 30 in the topical group [3.3%], four out of 30 in the control group [13.3%], and zero in the intravenous group). All were confirmed by duplex ultrasound scans and all were asymptomatic. Prevalence rates of DVT were similar between groups (p = 0.112 for control vs. intravenous; p = 0.353 for control vs. topical; and p =1.000 for intravenous vs. topical, according to two-sided exact tests).

Conclusions

Both topical and intravenous administration of TXA are safe with regard to occurrence of DVT, since the number of DVT cases in patients given TXA was not different to the number in those given placebo.

Fibrin gel versus papain gel in the healing of chronic venous ulcers: A double-blind randomized controlled trial

Objectives Compare the efficacy and safety of fibrin gel to 8% papain gel for wound dressing of venous ulcers. Method Patients with chronic venous ulcers were randomly assigned to one in three groups: Group 1-fibrin gel; Group 2-8% papain gel; Group 3-carbopol gel (control). Patients were seen every 15 days during 2 months, verifying reduction of the ulcer area, local infection, exudation, and epithelization. All serious or nonserious adverse events were recorded. Results Fifty-five patients (total of 63 ulcers) were randomly distributed in three groups (G1 = 21; G2 = 19; G3 = 23). No patient was excluded or discontinued treatment throughout the study. The areas of the ulcers were similarly reduced in all groups (14.3%, 21.1%, and 30.4% in groups 1, 2, and 3, respectively), and all had significant reduction in exudation and contamination. Conclusion The data demonstrate that neither fibrin gel nor papain gel were able to improve the process of ulcer-healing, as compared to control.

RNA therapeutics to control fibrinolysis: review on applications in biology and medicine

Regulation of fibrinolysis, the process that degrades blood clots, is pivotal in maintaining hemostasis. Dysregulation leads to thrombosis or excessive bleeding. Proteins in the fibrinolysis system include fibrinogen, coagulation factor XIII, plasminogen, tissue plasminogen activator, urokinase plasminogen activator, α2-antiplasmin, thrombin-activatable fibrinolysis inhibitor, plasminogen activator inhibitor-1, α2-macroglobulin, and others. While each of these is a potential therapeutic target for diseases, they lack effective or long-acting inhibitors. Rapid advances in RNA-based technologies are creating powerful tools to control the expression of proteins. RNA agents can be long-acting and tailored to either decrease or increase production of a specific protein. Advances in nucleic acid delivery, such as by lipid nanoparticles, have enabled the delivery of RNA to the liver, where most proteins of coagulation and fibrinolysis are produced. This review will summarize the classes of RNA that induce 1) inhibition of protein synthesis, including small interfering RNA and antisense oligonucleotides; 2) protein expression, including messenger RNA and self-amplifying RNA; and 3) gene editing for gene knockdown and precise editing. It will review specific examples of RNA therapies targeting proteins in the coagulation and fibrinolysis systems and comment on the wide range of opportunities for controlling fibrinolysis for biological applications and future therapeutics using state-of-the-art RNA therapies.