The Effects of Lysine Analogs During Pelvic Surgery: A Systematic Review and Meta-Analysis

Evaluation of the Safety and Effectiveness of Topical Intrapleural Application of Tranexamic Acid in Thoracic Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Bleeding remains a common complication post-thoracic surgery. Although intravenous tranexamic acid (TXA) has been shown to decrease blood loss, its use has been associated with adverse effects. Accordingly, topical TXA has been proposed as an alternative to reduce bleeding with fewer systemic complications.

METHODS

We searched Medline, Embase, and Cochrane Central databases for randomized controlled trials (RCTs) comparing topical TXA versus control (i.e., placebo) in patients undergoing thoracic procedures. The primary outcome was total postoperative blood loss at 24 hours. Secondary outcomes included were the number of red blood cell (RBC) transfusions, and hospital length of stay (LOS). Meta-analyses were pooled using mean difference with inverse-variance weighting and random-effects.

RESULTS

Out of the 575 unique studies that were screened, we identified three randomized controlled trials (RCTs) involving 399 patients. Out of the three RCTs analyzed, two studies, accounting for 67% of the total, were found to have a low risk of bias. The primary outcome of 24-h post-operative blood loss was significantly lower in patients who received TXA (mean difference [MD] -93.6 ml, 95% CI -121.8 to -65.4 ml, I2 = 45%). In addition, the need for RBC transfusion was significantly lower in the topical TXA group compared to control (MD -0.5 units, 95% CI -0.8 to -0.3 units, I2 = 60%). However, there was no significant difference in the hospital length of stay (LOS) (MD -0.3 days, 95% CI -0.9 to 0.4 days, I2 = 0%). These results remained consistent after several sensitivity analyses. The use of topical intrapleural tranexamic acid has also been found to be safe without any significant safety concerns.

CONCLUSION

Topical intrapleural TXA reduces blood loss and the need for blood transfusions during thoracic surgery. In addition, there is no evidence of the increased safety concerns associated with its use. Larger trials are necessary to validate these findings and evaluate the safety and efficacy of different dosages.

Tranexamic acid for prevention of bleeding in cesarean delivery: An overview of systematic reviews

BACKGROUND

Bleeding is the leading cause of maternal mortality in the world. Tranexamic acid reduces bleeding in trauma and surgery. Several systematic reviews of randomized trials have investigated tranexamic acid in the prevention of bleeding in cesarean delivery. However, the conclusions from systematic reviews are conflicting. This overview aims to summarize the evidence and explore the reasons for conflicting conclusions across the systematic reviews.

METHODS

A comprehensive literature search of Medline, Embase, and Cochrane Database of Systematic Reviews was conducted from inception to April 2021. Screening, data extraction, and quality assessments were performed by two independent reviewers. A Measurement Tool to Assess Reviews 2 and the Risk of Bias Assessment Tool for Systematic Reviews were used for study appraisal. A qualitative synthesis of evidence is presented.

RESULTS

In all, 14 systematic reviews were included in our analysis. Across these reviews, there were 32 relevant randomized trials. A modest reduction in blood transfusions and bleeding outcomes was found by most systematic reviews. Overall confidence in results varied from low to critically low. All of the included systematic reviews were at high risk of bias. Quality of evidence from randomized trials was uncertain.

CONCLUSIONS

Systematic reviews investigating prophylactic tranexamic acid in cesarean delivery are heterogeneous in terms of methodological and reporting quality. Tranexamic acid may reduce blood transfusion and bleeding outcomes, but rigorous well-designed research is needed due to the limitations of the included studies. Data on safety and adverse effects are insufficient to draw conclusions.

Safety and Efficacy of Using Tranexamic Acid at the Beginning of Robotic-Assisted Radical Prostatectomy in a Double-Blind Prospective Randomized Pilot Study

BACKGROUND

The prophylactic administration of tranexamic acid has been shown to be appropriate for procedures with a high risk of perioperative bleeding in cardiac surgery and orthopaedics. In urology the ambiguous results have been reported. Our goal was to evaluate the effect of tranexamic acid administration in robotic-assisted radical prostatectomy (RARP). A pilot, prospective, double-blind, randomized study was conducted to evaluate this effect.

METHODS

The study included 100 patients who received RARP in the period from April 2017 to January 2018. The patients were randomly assigned to study and control groups of 50 patients each.

RESULTS

The median follow-up was 6 months. Lower haemoglobin level drop weighted for gram of operated prostate was observed in the study group when treating the dorsal vein complex (DVC) at the beginning of the procedure (p = 0.004 after 3 hours and p < 0.001 after 24 hours). There was no evidence of any serious side effect of tranexamic acid.

CONCLUSION

We demonstrated the safety of tranexamic acid at RARP. In addition, we showed that administration of tranexamic acid at the beginning of RARP significantly reduces the decrease in haemoglobin after the procedure when treating the DVC at the beginning of the procedure.

Lysine analogue use during cancer surgery: a survey from a Canadian tertiary care centre

Background

When used during surgery, antifibrinolytic hemostatic agents such as lysine analogues are effective at reducing blood loss and the need for transfusions. Despite proven efficacy, use of hemostatic agents remains low during some surgeries. Our objective was to explore surgeon opinions about, and use of lysine analogues in, oncologic surgeries at a large tertiary care academic institution.

Methods

We administered a survey to surgeons who perform high-transfusion-risk oncologic surgeries at a large academic hospital in Ottawa, Ontario. Design and distribution of the survey followed a modified Dillman method. To ensure that the survey questionnaire was relevant, clear, and concise, we performed informant interviews, cognitive interviews, and pilot-testing. The final survey consisted of 19 questions divided into 3 sections: respondent demographics, use of hemostatic agents, and potential clinical trial opinions.

Results

Of 28 surgeons, 24 (86%) participated. When asked to indicate the frequency of lysine analogue use, "never" accounted for 46% of the responses, and "rarely" (<10% of the time) accounted for 23% of the responses. Reasons for never using included "unfamiliar with benefits" and "prefer alternatives." Fifteen surgeons (63%) felt that a trial was needed to demonstrate the efficacy and safety of lysine analogues in their cancer field.

Conclusions

Our survey found that lysine analogues are infrequently used during oncologic surgeries at our institution. Many surgeons are unfamiliar with the benefits and side effects of lysine analogues and, alternatively, use topical hemostatic agents. Our results demonstrate that future trials exploring the efficacy and safety of lysine analogues in oncologic surgery are needed.

Tranexamic acid in gynecologic surgery

Objective: To review the mechanism of action, pharmacology, dosing, and complications of tranexamic acid (TXA) and consolidate current evidence for TXA in gynecologic surgery.Methods: A literature search of PubMed, Ovid (MEDLINE), Google Scholar, and Elsevier was performed, in addition to a targeted search of cited references involving TXA and gynecologic surgery. Preference was given to systematic reviews and randomized control trials (RCTs).Results: TXA reversibly binds to plasminogen, preventing clot degradation. RCTs on hysterectomy, myomectomy, cervical conisation, hysteroscopy, and surgery for cervical and ovarian cancer were identified, as were case reports on TXA use for ectopic pregnancy. During hysterectomy, TXA reduces blood loss (two RCTs, n = 432, mean difference -66.0 mL and 180 mL), blood transfusion (1 RCT, n = 100, 12% vs. 42%, p < .00001). For myomectomy, a systematic review and meta-analysis showed a statistically significant decrease in blood loss with TXA (two RCTs, mean difference -213.1 mL, 95% CI: -242.4 mL to -183.7 mL). Following cervical conisation, TXA decreased the risk of delayed hemorrhage (four RCTs, RR 0.23, 95% CI: 0.11-0.50). A single RCT for cervical and ovarian cancer surgery demonstrated a decrease mean blood loss of 120 mL-135 mL and 210 mL, respectively, and fewer blood transfusions for the latter (OR 0.44, upper 95% CI: 0.97, p = .02). Less robust data suggest a possible benefit from TXA during hysteroscopy and surgery for ectopic pregnancies. Most commonly, 1 g of intravenous TXA is given intraoperatively.Conclusion: TXA is a safe adjunct that can be considered in a variety of gynecologic surgeries to decrease blood loss and risk of blood transfusion.

Perioperative management of patients with von Willebrand disease

Surgical procedures represent a serious hemostatic challenge for patients with von Willebrand disease (VWD), and careful perioperative management is required to minimize bleeding risk. Risk stratification includes not only the nature of the surgery to be performed but the baseline plasma von Willebrand factor (VWF) levels, bleeding history, and responses to previous challenges. Baseline bleeding scores (BSs) may assist in identification of patients with a higher risk of postsurgical bleeding. There remains a lack of consensus between best practice guidelines as to the therapeutic target and assays to be monitored in the postoperative period. Hemostatic levels are maintained until bleeding risk abates: usually 3 to 5 days for minor procedures and 7 to 14 days for major surgery. Hemostatic supplementation is more complex in VWD than in other bleeding disorders owing to the combined but variable deficiency of both plasma VWF and factor VIII (FVIII) levels. For emergency surgery, coadministration of VWF and FVIII is required to ensure hemostasis; however, for elective procedures, early infusion of VWF replacement therapy will stabilize endogenous FVIII. Because endogenous FVIII production is unaffected in patients with VWD, repeated VWF supplementation (particularly with plasma-derived FVIII-containing products) may lead to accumulation of FVIII. Frequent monitoring of plasma levels and access to hemostatic testing are, therefore, essential for patients undergoing major surgery, particularly with more severe forms of VWD.

Fibrinolysis Inhibitors: Potential Drugs for the Treatment and Prevention of Bleeding

Hyperfibrinolytic situations can lead to life-threatening bleeding, especially during cardiac surgery. The approved antifibrinolytic agents such as tranexamic acid, ε-aminocaproic acid, 4-aminomethylbenzoic acid, and aprotinin were developed in the 1960s without the structural insight of their respective targets. Crystal structures of the main antifibrinolytic targets, the lysine binding sites on plasminogen's kringle domains, and plasmin's serine protease domain greatly contributed to the structure-based drug design of novel inhibitor classes. Two series of ligands targeting the lysine binding sites have been recently described, which are more potent than the most-widely used antifibrinolytic agent, tranexamic acid. Furthermore, four types of promising active site inhibitors of plasmin have been developed: tranexamic acid conjugates targeting the S1 pocket and primed sites, substrate-analogue linear homopiperidylalanine-containing 4-amidinobenzylamide derivatives, macrocyclic inhibitors addressing nonprimed binding regions, and bicyclic 14-mer SFTI-1 analogues blocking both, primed and nonprimed binding sites of plasmin. Furthermore, several allosteric plasmin inhibitors based on heparin mimetics have been developed.

Tranexamic Acid versus Placebo to Prevent Blood Transfusion during Radical Cystectomy for Bladder Cancer (TACT): Study Protocol for a Randomized Controlled Trial

BACKGROUND

Radical cystectomy for bladder cancer is associated with a high risk of needing red blood cell transfusion. Tranexamic acid reduces blood loss during cardiac and orthopedic surgery, but no study has yet evaluated tranexamic acid use during cystectomy.

METHODS

A randomized, double-blind (surgeon-, anesthesiologist-, patient-, data-monitor-blinded), placebo-controlled trial of tranexamic acid during cystectomy was initiated in June 2013. Prior to incision, the intervention arm participants receive a 10 mg/kg loading dose of intravenously administered tranexamic acid, followed by a 5 mg/kg/h maintenance infusion. In the control arm, the patient receives an identical volume of normal saline that is indistinguishable from the intervention. The primary outcome is any blood transfusion from the start of surgery up to 30 days post operative. There are no strict criteria to mandate the transfusion of blood products. The decision to transfuse is entirely at the discretion of the treating physicians who are blinded to patient allocation. Physicians are allowed to utilize all resources to make transfusion decisions, including serum hemoglobin concentration and vital signs. To date, 147 patients of a planned 354 have been randomized to the study.

DISCUSSION

This protocol reviews pertinent data relating to blood transfusion during radical cystectomy, highlighting the need to identify methods for reducing blood loss and preventing transfusion in patients receiving radical cystectomy. It explains the clinical rationale for using tranexamic acid to reduce blood loss during cystectomy, and outlines the study methods of our ongoing randomized controlled trial.

TRIAL REGISTRATIONS

Canadian Institute for Health Research (CIHR) Protocol: MOP-342559; ClinicalTrials.gov, ID: NCT01869413. Registered on 5 June 2013.

The efficacy and safety of topical tranexamic acid: A systematic review and meta-analysis

Tranexamic acid (TXA) is an effective hemostatic agent used for the reduction of blood loss and transfusion. However, the safety profile of TXA remains in question due to a potential increased risk of venous thromboembolism. By applying TXA topically as opposed to intravenously, systemic absorption may be reduced and unwanted side-effects mitigated. The objective of our review is to investigate the efficacy and safety of topically applied tranexamic acid compared to both placebo, and the intravenous administration. Cochrane Central Register of Controlled Trials, MEDLINE, Embase, ISI Web of Science, PubMed, and Clinicaltrials.gov were searched from inception to November, 2016. We included randomized controlled trials that compared topical tranexamic acid to either placebo (or standard care) or intravenous administration, in adult patients. Surgical and non-surgical trials were included. Abstract, full-text selection, data extraction and risk of bias assessment were all performed in duplicate. In total, 67 studies involving 6,034 patients met inclusion criteria. The majority of trials evaluated orthopedic procedures. Compared to placebo, the administration of topical TXA significantly reduced the odds of receiving a blood transfusion (pooled OR 0.28, 95% CI 0.20 to 0.38; P < 0.001) and significantly reduced mean blood loss (WMD -276.6, 95% CI -327.8 to -225.4; P < 0.0001). When compared to the intravenous administration, there was no difference between the two groups in terms of transfusion requirements (pooled OR 1.03, 95% CI 0.72 to 1.46; P=0.88) or blood loss (WMD -21.95, 95% CI -66.61 to 27.71; P=0.34). There was no difference in the odds of developing a venous thromboembolic complication between the topical TXA and control groups (pooled OR=0.78, 95% CI 0.47 to 1.29; P=0.33) or the topical and intravenous groups (pooled OR=0.75, 95% CI 0.39 to 1.46; P=0.40). The topical application of TXA effectively reduces both transfusion risk and blood loss compared to placebo, without increasing thromboembolic risks. There were no major differences between topical and intravenous tranexamic acid with respect to safety and efficacy, and both were superior to placebo with regards to blood loss and transfusion requirements. Further study of the topical application is required outside of the field of orthopedics.

Management of the Jehovah's Witness in Obstetrics and Gynecology: A Comprehensive Medical, Ethical, and Legal Approach

IMPORTANCE

Obstetricians and gynecologists frequently deal with hemorrhage so they should be familiar with management of patients who refuse blood transfusion. Although there are some reports in the literature about management of Jehovah's Witness patients in obstetrics and gynecology, most of them are case reports, and a comprehensive review about these patients including ethicolegal perspective is lacking.

OBJECTIVE

This review outlines the medical, ethical, and legal implications of management of Jehovah's Witness patients in obstetrical and gynecological settings.

EVIDENCE ACQUISITION

A search of published literature using PubMed, Ovid Medline, EMBASE, and Cochrane databases was conducted about physiology of oxygen delivery and response to tissue hypoxia, mortality rates at certain hemoglobin levels, medical management options for anemic patients who refuse blood transfusion, and ethical/legal considerations in Jehovah's Witness patients.

RESULTS

Early diagnosis of anemia and immediate initiation of therapy are essential in patients who refuse blood transfusion. Medical management options include iron supplementation and erythropoietin. There are also some promising therapies that are in development such as antihepcidin antibodies and hemoglobin-based oxygen carriers. Options to decrease blood loss include antifibrinolytics, desmopressin, recombinant factor VII, and factor concentrates. When surgery is the only option, every effort should be made to pursue minimally invasive approaches.

CONCLUSION AND RELEVANCE

All obstetricians and gynecologists should be familiar with alternatives and "less invasive" options for patients who refuse blood transfusions.