A comparison of aprotinin and lysine analogues in high-risk cardiac surgery

A Narrative Review of 99mTc-Aprotinin in the Diagnosis of Cardiac Amyloidosis and a New Life for an Unfairly Abandoned Drug

Several studies investigated the use of 99mTc-labelled Aprotinin as an amyloid seeker some years ago. In vitro tests showed high binding affinity for several types of amyloid fibrils accompanied by an excellent specificity. Initial human studies demonstrated good accuracy in detecting cardiac involvement. Scintigraphy results were confirmed in a group of 28 endomyocardial biopsies. Unfortunately, clinical studies were halted because of a temporary suspension of the vector protein (Trasylol) and public health concerns over prion contamination of the bovine origin compound. To obviate these limitations, efforts have been made to label a recombinant Aprotinin with 99mTc, which exhibits the same affinity for h-insulin fibrils. With the aim of developing a PET tracer, the same recombinant protein was labeled with Gallium. The introduction of a bifunctional chelator did not affect fibril affinity. Finally, a synthetic peptidic fragment, the cyclic 30-51 SS, was synthetized. After direct technetium labeling, an impressive increase in affinity was demonstrated. This peptide appears to be a potential candidate for Gallium labeling through a bifunctional chelator for PET imaging.

Agreement of treatment effects from observational studies and randomized controlled trials evaluating hydroxychloroquine, lopinavir-ritonavir, or dexamethasone for covid-19: meta-epidemiological study

OBJECTIVE

To systematically identify, match, and compare treatment effects and study demographics from individual or meta-analysed observational studies and randomized controlled trials (RCTs) evaluating the same covid-19 treatments, comparators, and outcomes.

DESIGN

Meta-epidemiological study.

DATA SOURCES

National Institutes of Health Covid-19 Treatment Guidelines, a living review and network meta-analysis published in The BMJ, a living systematic review with meta-analysis and trial sequential analysis in PLOS Medicine (The LIVING Project), and the Epistemonikos "Living OVerview of Evidence" (L·OVE) evidence database.

ELIGIBILITY CRITERIA FOR SELECTION OF STUDIES

RCTs in The BMJ's living review that directly compared any of the three most frequently studied therapeutic interventions for covid-19 across all data sources (that is, hydroxychloroquine, lopinavir-ritonavir, or dexamethasone) for any safety and efficacy outcomes. Observational studies that evaluated the same interventions, comparisons, and outcomes that were reported in The BMJ's living review.

DATA EXTRACTION AND SYNTHESIS

Safety and efficacy outcomes from observational studies were identified and treatment effects for dichotomous (odds ratios) or continuous (mean differences or ratios of means) outcomes were calculated and, when possible, meta-analyzed to match the treatment effects from individual RCTs or meta-analyses of RCTs reported in The BMJ's living review with the same interventions, comparisons, and outcomes (that is, matched pairs). The analysis compared the distribution of study demographics and the agreement between treatment effects from matched pairs. Matched pairs were in agreement if both observational and RCT treatment effects were significantly increasing or decreasing (P<0.05) or if both treatment effects were not significant (P≥0.05).

RESULTS

17 new, independent meta-analyses of observational studies were conducted that compared hydroxychloroquine, lopinavir-ritonavir, or dexamethasone with an active or placebo comparator for any safety or efficacy outcomes in covid-19 treatment. These studies were matched and compared with 17 meta-analyses of RCTs reported in The BMJ's living review. 10 additional matched pairs with only one observational study and/or one RCT were identified. Across all 27 matched pairs, 22 had adequate reporting of demographical and clinical data for all individual studies. All 22 matched pairs had studies with overlapping distributions of sex, age, and disease severity. Overall, 21 (78%) of the 27 matched pairs had treatment effects that were in agreement. Among the 17 matched pairs consisting of meta-analyses of observational studies and meta-analyses of RCTs, 14 (82%) were in agreement; seven (70%) of the 10 matched pairs consisting of at least one observational study or one RCT were in agreement. The 18 matched pairs with treatment effects for dichotomous outcomes had a higher proportion of agreement (n=16, 89%) than did the nine matched pairs with treatment effects for continuous outcomes (n=5, 56%).

CONCLUSIONS

Meta-analyses of observational studies and RCTs evaluating treatments for covid-19 have summary treatment effects that are generally in agreement. Although our evaluation is limited to three covid-19 treatments, these findings suggest that meta-analyzed evidence from observational studies might complement, but should not replace, evidence collected from RCTs.

Association of Phlebotomy on Blood Product Transfusion Requirements During Liver Transplantation: An Observational Cohort Study on 1000 Cases

Background

During the past 2 decades, transfusion requirements have decreased drastically during orthotopic liver transplantation (OLT), and transfusion-free transplantation is nowadays increasingly common. Understanding that liberal intravenous volume loading in cirrhotic patients may have detrimental consequences is key. In contrast, phlebotomy is a method to lower central venous pressure and portal venous pressure. The objective of this study was to determine the effectiveness and safety of phlebotomy in the early phase of blood transfusion, blood loss, renal function, and mortality.

Methods

The present study evaluated the impact of phlebotomy on bleeding, transfusion rate, renal dysfunction, and mortality in 1000 consecutive OLTs. Two groups were defined and compared using phlebotomy. Multivariate logistic and linear regression models were used to determine predictors of bleeding, red blood cell (RBC) transfusion, renal dysfunction, and mortality.

Results

A mean of 0.7 ± 1.5 RBC units was transfused per patient for 1000 OLTs, 75% did not receive any RBCs, and the median and interquartile range (25-75) were 0 for all blood products transfused. The phlebotomy was associated with decreased transfusion (RBCs, plasma, platelets, cryoprecipitate, albumin), with less bleeding, and with an increased survival rate, both 1 mo and 1 y. Phlebotomy was not associated with renal dysfunction.

Conclusions

The practice of phlebotomy to lower portal venous pressure was associated with reduced blood product transfusions and blood loss during liver dissection without deleterious effect on renal function.

Efficacy and safety of aprotinin in paediatric cardiac surgery: A systematic review and meta-analysis

BACKGROUND

The relicensing of aprotinin in Europe and Canada has stimulated discussions on its usefulness in paediatric cardiac surgery.

OBJECTIVE

To systematically evaluate the available evidence on the efficacy and safety of aprotinin in paediatric cardiac surgery.

DESIGN

Systematic review of all randomised and observational studies comparing aprotinin with tranexamic acid, epsilon aminocaproic acid, placebo or no drug in paediatric cardiac surgery. Meta-analyses were performed on efficacy and safety outcomes.

DATA SOURCES

PubMed, Cochrane Central Register of Controlled Trials, Web of Science and Embase were searched from January 2000 to March 2021.

ELIGIBILITY CRITERIA

Studies that enrolled children under 18 years undergoing cardiac surgery with cardiopulmonary bypass.

RESULTS

Thirty-two studies enrolling a total of 63 894 paediatric cardiac procedures were included. Aprotinin significantly reduced total blood loss [mean difference -4.70 ml kg-1, 95% confidence interval (CI), -7.88 to -1.53; P = 0.004], postoperative transfusion requirements and the incidence of surgical re-exploration for bleeding [odds ratio (OR) 0.74, 95% CI, 0.56 to 0.97; P = 0.03]. Aprotinin had no effects on 30-day mortality (OR 1.02, 95% CI, 0.93 to 1.11; P = 0.73) and on other safety outcomes, except for the incidence of renal replacement therapy (RRT), which was significantly increased in patients given aprotinin (OR 1.29, 95% CI, 1.08 to 1.54; P = 0.006). Findings from observational and randomised controlled trials did not largely differ. A sub-group analysis in neonates showed that aprotinin significantly reduced packed red blood cell transfusions and the incidence of postoperative surgical re-exploration for bleeding and/or tamponade. When compared with lysine analogues, aprotinin was more effective at reducing bleeding and transfusion without increasing the risk of side effects.

CONCLUSION

This meta-analysis suggests that aprotinin is effective and well tolerated in paediatric cardiac surgery. Given the large heterogeneity of the results and the risk of selection bias in observational studies, large randomised controlled trials are warranted.

Tranexamic Acid Use During Surgery Associated with Extension of Acute Perioperative Type 1 Myocardial Infarction: A Case Report

CASE PRESENTATION

A 70-year-old women presented to a regional hospital after a fall, resulting in a periprosthetic femoral fracture. Preoperative echocardiogram was ordered to investigate a cardiac murmur, and unexpectedly, a significant regional wall abnormality was found. Further repeat electrocardiograph and troponin blood biomarker analysis demonstrated the patient had suffered an acute type 1 myocardial infarction after admission to the ward, without exhibiting classical ischemic cardiac symptoms. A multidisciplinary decision was made for the patient to proceed to surgery, and at that time, she received tranexamic acid (TXA). Postoperatively, there was notable echocardiographic extension of the infarction, which required transfer to a tertiary center for management with complex coronary artery stenting. The patient once discharged was followed up by cardiology at the 3-month interval.

CONCLUSION

The use of TXA in arterial thromboembolic disease requires thorough consideration because it may contribute to further myocardial damage. A patient-specific approach should be adopted with the risk of thrombosis extension being considered.

Safety and Efficacy of Local Tranexamic Acid for the Prevention of Surgical Bleeding in Soft-Tissue Surgery: A Review of the Literature and Recommendations for Plastic Surgery

BACKGROUND

Although high-bleed surgery routinely utilizes the antifibrinolytic drug tranexamic acid, most plastic surgical procedures are conducted in soft tissue with low-volume bleeding. Unease regarding possible systemic adverse effects prevents widespread systemic use, but local use of tranexamic acid is gaining popularity among plastic surgeons. Randomized controlled trials on topical use of tranexamic acid are mainly from high-bleed surgeries, and few studies address the effect in soft tissue. This article reviews the scientific evidence regarding local use of tranexamic acid in soft-tissue surgery, discusses pharmacological effects and possible adverse reactions, and presents recommendations for use in plastic surgery.

METHODS

A systematic search of databases for studies on local use of tranexamic acid in soft-tissue surgery was performed. Randomized controlled trials were included for a systematic review on effect; a narrative review regarding other clinically relevant aspects is based on extensive literature searches combined with the authors' own research.

RESULTS

Fourteen randomized controlled trials, including 1923 patients, were included in the systematic review on local use of tranexamic acid in soft-tissue surgery.

CONCLUSIONS

Local use of tranexamic acid may reduce blood loss comparably to intravenous prophylactic use with negligible risk of systemic adverse effects, but high-quality randomized controlled trials are few. Prolonged exposure to high local concentrations is discouraged, and direct contact with the central nervous system may cause seizures. No single superior means of administration or dosage is supported in the literature, and lowest effective dose is unknown. There may not be one single ideal dosing regimen, but rather many possibilities adaptable for different surgical situations.

Tranexamic acid versus placebo to reduce perioperative blood transfusion in patients undergoing liver resection: protocol for the haemorrhage during liver resection tranexamic acid (HeLiX) randomised controlled trial

INTRODUCTION

Despite use of operative and non-operative interventions to reduce blood loss during liver resection, 20%-40% of patients receive a perioperative blood transfusion. Extensive intraoperative blood loss is a major risk factor for postoperative morbidity and mortality and receipt of blood transfusion is associated with serious risks including an association with long-term cancer recurrence and overall survival. In addition, blood products are scarce and associated with appreciable expense; decreasing blood transfusion requirements would therefore have health system benefits. Tranexamic acid (TXA), an antifibrinolytic, has been shown to reduce the probability of receiving a blood transfusion by one-third for patients undergoing cardiac or orthopaedic surgery. However, its applicability in liver resection has not been widely researched.

METHODS AND ANALYSIS

This protocol describes a prospective, blinded, randomised controlled trial being conducted at 10 sites in Canada and 1 in the USA. 1230 eligible and consenting participants will be randomised to one of two parallel groups: experimental (2 g of intravenous TXA) or placebo (saline) administered intraoperatively. The primary endpoint is receipt of blood transfusion within 7 days of surgery. Secondary outcomes include blood loss, postoperative complications, quality of life and 5-year disease-free and overall survival.

ETHICS AND DISSEMINATION

This trial has been approved by the research ethics boards at participating centres and Health Canada (parent control number 177992) and is currently enrolling participants. All participants will provide written informed consent. Results will be distributed widely through local and international meetings, presentation, publication and ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT02261415.

Tranexamic Acid Administered During Off-Pump Coronary Artery Bypass Graft Surgeries Achieves Good Safety Effects and Hemostasis

BACKGROUND

Tranexamic acid (TXA) administered during off-pump coronary artery bypass (OPCAB) surgeries has achieved good blood control in small cohorts. We aimed to investigate the safety issues and hemostasis associated with TXA administration during OPCAB in a large retrospective cohort study.

METHODS

This study included 19,687 patients with OPCAB from 2009 to 2019. A total of 1,307 patients were excluded because they were younger than 18 years or certain values were missing. Among the remaining 18,380 patients, 10,969 were in the TXA group and 7,411 patients were in the no-TXA group. There were 4,889 patients whose TXA dose was ≥50 mg/kg, and the remaining 6,080 patients had a TXA dose of <50 mg/kg. Propensity score matching (PSM) was performed between the TXA and no-TXA groups and between the high-dose and low-dose groups, and statistical analysis was performed.

RESULTS

Tranexamic acid administration did not increase the risk of hospital death or thromboembolic events. Patients who administered TXA had less blood loss at 24 h (478.32 ± 276.41 vs. 641.28 ± 295.09, p < 0.001) and 48 h (730.59 ± 358.55 vs. 915.24 ± 390.13, p < 0.001) and total blood loss (989.00 ± 680.43 vs. 1,220.01 ± 720.68, p < 0.001) after OPCAB than the patients with non-TXA. Therefore, the risk of total blood exposure [odds ratio (OR) = 0.50, 95% CI 0.47-0.54, p < 0.001] or blood component exposure (p < 0.001) was decreased significantly in the patients who administered TXA. The TXA dosage did not impact the patient survival, thromboembolic events, or blood management.

CONCLUSIONS

The application of TXA was safe and provided blood control in patients with OPCAB, and the dosage did not affect these parameters.

Does preoperative dual antiplatelet therapy affect bleeding and mortality after total arch repair for acute type A dissection?

OBJECTIVES

Data are scarce and mixed regarding the impact of preoperative dual antiplatelet therapy (DAPT) on the surgical outcomes of acute type A aortic dissection (ATAAD). We seek to evaluate the impact of DAPT on bleeding-related events and early- and mid-term mortality after total arch replacement and frozen elephant trunk in such patients.

METHODS

This study comprised 48 ATAAD patients on preoperative DAPT and 418 without DAPT (the whole series, i.e. unmatched cohort), from which 45 matched pairs were selected by propensity score (matched cohort). Bleeding-related events (reoperation for bleeding, bleeding of ≥1500 ml within the first 12 h postoperatively or transfusion of ≥10 units of red blood cell or use of recombinant activated factor VII), operative mortality and mid-term survival were compared in the unmatched and matched cohorts. The impact of preoperative DAPT was evaluated with multivariable analysis.

RESULTS

In the unmatched cohort, bleeding of ≥1500 ml/12 h postoperatively was more common in the DAPT group (18.8% vs 8.4%, P = 0.020); operative mortality was 9.7%, which did not differ with DAPT (12.5% vs 9.3%, P = 0.48). Nor did bleeding-related events (54.2% vs 43.5%, P = 0.16) differ significantly between 2 groups. In the matched cohort, neither were drainage of ≥1500 ml/12 h (20% vs 6.7%, P = 0.063) and bleeding-related events (53.3% vs 42.2%, P = 0.30), nor operative mortality (13.8 vs 8.9%, P = 0.50) and mid-term survival (79.3% vs 76.4%, P = 0.93) significantly different between 2 groups. DAPT was not identified as a predictor for operative mortality [odd ratio (OR) 0.97, 95% confidence interval (CI) 0.31-3.08; P = 0.96; adjusted OR 1.28, 95% CI 0.22-7.20; P = 0.78] and bleeding-related events (OR 1.50, 95% CI 0.76-2.95; P = 0.24; adjusted OR 2.03, 95% CI 0.80-3.66; P = 0.14).

CONCLUSIONS

In patients with ATAAD undergoing total arch replacement and frozen elephant trunk, although preoperative DAPT led to more postoperative bleeding, it did not increase bleeding-related events nor operative mortality nor mid-term death. The results of this study imply that for patients with ATAAD, emergency surgical repair, even if as extensive as total arch repair, should not be contraindicated or delayed simply because of ongoing DAPT.

Tranexamic Acid Administered During Off-Pump Coronary Artery Bypass Graft Surgeries Achieves Good Safety Effects and Hemostasis

BACKGROUND

Tranexamic acid (TXA) administered during off-pump coronary artery bypass (OPCAB) surgeries has achieved good blood control in small cohorts. We aimed to investigate the safety issues and hemostasis associated with TXA administration during OPCAB in a large retrospective cohort study.

METHODS

This study included 19,687 patients with OPCAB from 2009 to 2019. A total of 1,307 patients were excluded because they were younger than 18 years or certain values were missing. Among the remaining 18,380 patients, 10,969 were in the TXA group and 7,411 patients were in the no-TXA group. There were 4,889 patients whose TXA dose was ≥50 mg/kg, and the remaining 6,080 patients had a TXA dose of <50 mg/kg. Propensity score matching (PSM) was performed between the TXA and no-TXA groups and between the high-dose and low-dose groups, and statistical analysis was performed.

RESULTS

Tranexamic acid administration did not increase the risk of hospital death or thromboembolic events. Patients who administered TXA had less blood loss at 24 h (478.32 ± 276.41 vs. 641.28 ± 295.09, p < 0.001) and 48 h (730.59 ± 358.55 vs. 915.24 ± 390.13, p < 0.001) and total blood loss (989.00 ± 680.43 vs. 1,220.01 ± 720.68, p < 0.001) after OPCAB than the patients with non-TXA. Therefore, the risk of total blood exposure [odds ratio (OR) = 0.50, 95% CI 0.47-0.54, p < 0.001] or blood component exposure (p < 0.001) was decreased significantly in the patients who administered TXA. The TXA dosage did not impact the patient survival, thromboembolic events, or blood management.

CONCLUSIONS

The application of TXA was safe and provided blood control in patients with OPCAB, and the dosage did not affect these parameters.

Renal effects of the serine protease inhibitor aprotinin in healthy conscious mice

Treatment with aprotinin, a broad-spectrum serine protease inhibitor with a molecular weight of 6512 Da, was associated with acute kidney injury, which was one of the reasons for withdrawal from the market in 2007. Inhibition of renal serine proteases regulating the epithelial sodium channel ENaC could be a possible mechanism. Herein, we studied the effect of aprotinin in wild-type 129S1/SvImJ mice on sodium handling, tubular function, and integrity under a control and low-salt diet. Mice were studied in metabolic cages, and aprotinin was delivered by subcutaneously implanted sustained release pellets (2 mg/day over 10 days). Mean urinary aprotinin concentration ranged between 642 ± 135 (day 2) and 127 ± 16 (day 8) µg/mL . Aprotinin caused impaired sodium preservation under a low-salt diet while stimulating excessive hyperaldosteronism and unexpectedly, proteolytic activation of ENaC. Aprotinin inhibited proximal tubular function leading to glucosuria and proteinuria. Plasma urea and cystatin C concentration increased significantly under aprotinin treatment. Kidney tissues from aprotinin-treated mice showed accumulation of intracellular aprotinin and expression of the kidney injury molecule 1 (KIM-1). In electron microscopy, electron-dense deposits were observed. There was no evidence for kidney injury in mice treated with a lower aprotinin dose (0.5 mg/day). In conclusion, high doses of aprotinin exert nephrotoxic effects by accumulation in the tubular system of healthy mice, leading to inhibition of proximal tubular function and counterregulatory stimulation of ENaC-mediated sodium transport.

Cardiac Surgery and Blood-Saving Techniques: An Update

Cardiac surgery is typically attributed with a significant risk of intraoperative blood loss and allogeneic blood transfusions. Intraoperative blood loss, allogenic blood transfusions, high dose anticoagulation requirement, and interactions with cardiopulmonary bypass (CPB) have all been linked to cardiac surgeries. To reduce unnecessary transfusions and their negative effects, it is recommended to follow evidence-based multidisciplinary strategies, which are collectively termed patient blood management (PBM). This review highlights the most recent blood conservation strategies in adult cardiac surgery, which can be employed pre-operatively, intra-operatively, and postoperatively, to enhance red cell mass and attenuate the utilization of packed red blood cells (PRBCs) and other blood products.

Blood conservation outcomes and safety of tranexamic acid in coronary artery bypass graft surgery

BACKGROUND

The safety and blood management effects of Tranexamic acid (TXA) and its dose effects in coronary artery bypass graft (CABG) were still ambiguous. This study aimed to analyze these TXA effects.

METHODS

Overall, 42,010 patients undergoing CABG were enrolled in this retrospective cohort study. Patients were assigned to the TXA group (n = 29,536) and the no-TXA group (n = 12,474). Furthermore, the TXA group was divided into the high-dose (≥50 mg/kg) (16,488) and the low-dose (<50 mg/kg) (13,048) subgroup. Propensity score matching was performed in both groups respectively. The primary endpoint after CABG was composed of hospital death, perioperative myocardial infarction (PMI), stroke, acute kidney injury (AKI), and pulmonary embolism. The secondary endpoint included blood loss and blood transfusion after surgery.

RESULTS

TXA led to a 1.40-fold risk of PMI (p < 0.001). Patients in the TXA group had fewer re-operations for bleeding or tamponade [Odd ratio (OR) = 0.82, p = 0.044], less blood loss after surgery (p < 0.001), and a lower risk for blood transfusion exposure (OR = 0.45, p < 0.001) than those in the no-TXA group. The high-dose TXA reduced blood loss after cardiac surgery compared to the low-dose TXA (p < 0.001) with no associations with blood exposure or adverse events.

CONCLUSIONS

The use of TXA during CABG increased the risk of PMI despite better blood control after surgery. The high dose of TXA acquired better bleeding management. Meanwhile, it did not increase the risk of primary endpoint.

Effect of Aprotinin on Liver Injury after Transplantation of Extended Criteria Donor Grafts in Humans: A Retrospective Propensity Score Matched Cohort Analysis

The number of patients awaiting liver transplantation still widely exceeds the number of donated organs available. Patients receiving extended criteria donor (ECD) organs are especially prone to an aggravated ischemia reperfusion syndrome during liver transplantation leading to massive hemodynamic stress and possible impairment in organ function. Previous studies have demonstrated aprotinin to ameliorate reperfusion injury and early graft survival. In this single center retrospective analysis of 84 propensity score matched patients out of 274 liver transplantation patients between 2010 and 2014 (OLT), we describe the association of aprotinin with postreperfusion syndrome (PRS), early allograft dysfunction (EAD: INR 1,6, AST/ALT > 2000 within 7–10 days) and recipient survival. The incidence of PRS (52.4% vs. 47.6%) and 30-day mortality did not differ (4.8 vs. 0%; p = 0.152) but patients treated with aprotinin suffered more often from EAD (64.3% vs. 40.5%, p = 0.029) compared to controls. Acceptable or poor (OR = 3.3, p = 0.035; OR = 9.5, p = 0.003) organ quality were independent predictors of EAD. Our data do not support the notion that aprotinin prevents nor attenuates PRS, EAD or mortality.

Clopidogrel Loading Dose 300 vs. 600 mg in Patients Undergoing One-Stop Hybrid Coronary Revascularization: A Prospective Single-Center Randomized Pilot Study

Background: The optimal loading dose of clopidogrel in one-stop hybrid coronary revascularization (HCR) remains an “evidence-free” zone. This study aimed to compare the major bleeding and ischemic thrombotic events between different clopidogrel loading doses (300 vs. 600 mg) in one-stop HCR.

Methods: In this prospective, single-center, randomized, and parallel pilot study, 100 patients receiving one-stop HCR were randomly assigned to the clopidogrel loading dose 300-mg group or 600-mg group in a 1:1 ratio. Major bleeding events and composite in-hospital ischemic thrombotic and adverse complications were evaluated after the procedure.

Results: The results showed that postoperative mean chest drainage of the first 4 days and total drainage were comparable between the two groups. No differences were found in Bleeding Academic Research Consortium (BARC) coronary artery bypass grafting (CABG) related bleeding (4 vs. 2%, P = 1), PLATelet inhibition and patient Outcomes (PLATO) life-threatening bleeding (20 vs. 26%, P = 0.48), and PLATO major bleeding (70 vs. 76%, P = 0.5) in the two groups. The composite ischemic thrombotic and adverse events were also similar.

Conclusions: In patients receiving one-stop HCR, clopidogrel 600 mg loading dose did not increase major bleeding events compared with 300 mg. More sufficient data is necessary to evaluate the potential benefits of 600 mg loading dose in one-stop HCR.

Antifibrinolytic Drugs for the Prevention of Bleeding in Pediatric Cardiac Surgery on Cardiopulmonary Bypass: A Systematic Review and Meta-analysis

BACKGROUND

Bleeding is one of the commonest complications affecting children undergoing cardiac surgery on cardiopulmonary bypass. Antifibrinolytic drugs are part of a multifaceted approach aimed at reducing bleeding, though sufficiently sized pediatric studies are sparse, and dosing algorithms are heterogeneous. Our objective was to evaluate the efficacy and safety of antifibrinolytic agents as well as the effectiveness of different dosing regimens in pediatric cardiac surgery using cardiopulmonary bypass.

METHODS

We performed a systematic review and meta-analysis evaluating randomized controlled trials published between 1980 and 2019, identified by searching the databases MEDLINE, EMBASE, PubMed, and CENTRAL. All studies investigating patients <18 years of age without underlying hematological disorders were included. The primary outcome was postoperative bleeding; secondary end points included blood product transfusion, mortality, and safety (thromboses, anaphylaxis, renal or neurological dysfunction, and seizures). Different dosing regimens were compared. Studies were dual appraised, outcomes were reported descriptively and, if appropriate, quantitatively using the Review Manager 5 (REVMAN 5) software (The Cochrane Collaboration).

RESULTS

Thirty of 209 articles were included, evaluating the following drugs versus control: aprotinin n = 14, tranexamic acid (TXA) n = 12, and epsilon-aminocaproic acid (EACA) n = 4. The number of participants per intervention group ranged from 11 to 100 (median, 25; interquartile range [IQR], 20.5) with a wide age span (mean, 13 days to 5.8 years) and weight range (mean, 3.1-26.3 kg). Methodological quality was low to moderate.All agents reduced mean 24-hour blood loss compared to control: aprotinin by 6.0 mL/kg (95% confidence interval [CI], -9.1 to -3.0; P = .0001), TXA by 9.0 mL/kg (95% CI, -11.3 to -6.8; P < .00001), and EACA by 10.5 mL/kg (95% CI, -21.1 to 0.0; P = .05). Heterogeneity was low for TXA (I2 = 29%; P = .19), moderate for aprotinin (I2 = 41%; P = .11), and high for EACA (I2 = 95%; P = <.00001). All agents also reduced 24-hour blood product transfusion. There was no clear dose-response effect for TXA nor aprotinin. Studies were underpowered to detect significant differences in mortality, thromboses, anaphylaxis, and renal or neurological dysfunction.

CONCLUSIONS

The available data demonstrate efficacy for all 3 antifibrinolytic drugs. Therefore, the agent with the most favorable safety profile should be used. As sufficient data are lacking, large comparative trials are warranted to assess the relative safety and appropriate dosing regimens in pediatrics.

Clinical use of tranexamic acid: evidences and controversies

Tranexamic acid (TXA) significantly reduces blood loss in a wide range of surgical procedures and improves survival rates in obstetric and trauma patients with severe bleeding. Although it mainly acts as a fibrinolysis inhibitor, it also has an anti-inflammatory effect, and may help attenuate the systemic inflammatory response syndrome found in some cardiac surgery patients. However, the administration of high doses of TXA has been associated with seizures and other adverse effects that increase the cost of care, and the administration of TXA to reduce perioperative bleeding needs to be standardized. Tranexamic acid is generally well tolerated, and most adverse reactions are considered mild or moderate. Severe events are rare in clinical trials, and literature reviews have shown tranexamic acid to be safe in several different surgical procedures. However, after many years of experience with TXA in various fields, such as orthopedic surgery, clinicians are now querying whether the dosage, route and interval of administration currently used and the methods used to control and analyze the antifibrinolytic mechanism of TXA are really optimal. These issues need to be evaluated and reviewed using the latest evidence to improve the safety and effectiveness of TXA in treating intracranial hemorrhage and bleeding in procedures such as liver transplantation, and cardiac, trauma and obstetric surgery.

Tranexamic acid after cardiopulmonary bypass does not increase risk of postoperative seizures: a retrospective study

OBJECTIVE

To evaluate the effects of administering tranexamic acid (TXA) after cardiopulmonary bypass, instead of after anesthesia induction, on postoperative seizures and blood transfusion requirements.

METHODS

Adult patients who underwent valve surgery and/or coronary artery bypass grafting at West China Hospital between July 1, 2011 and December 31, 2016 were retrospectively analyzed. Patients either received TXA after bypass (n = 2062) or not (n = 4236). Logistic regression and propensity score matching analysis were performed to assess effects of TXA on postoperative seizures and blood product requirements in hospital.

RESULTS

Among 6298 patients, seizures occurred in 2.4% (102/4236) in the no-TXA group and 2.7% (56/2062) in the TXA group (P = 0.46). The number of patients receiving any blood products was greater in the no-TXA group (57.3%, 2428/4236) than in the TXA group (53.1%, 1095/2062) (P < 0.01), and the volume of blood products was also greater in the no-TXA group (1.5 vs. 1.0 units, P < 0.01). TXA was not associated with increased incidence of postoperative seizures (adjusted OR 1.16, 95% CI 0.83-1.62) but was associated with lower incidence of a requirement for blood products (adjusted OR 0.82, 95% CI 0.73-0.92). Similar results were obtained after patients from the two groups were matched based on propensity scoring. TXA was associated with reduced requirements for fresh frozen plasma, platelets and cryoprecipitate, but not red blood cells.

CONCLUSIONS

Administering TXA after bypass may reduce requirements for blood products without increasing risk of seizures following cardiac surgery.

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.

The efficacy of Tranexamic Acid Administration in Patients Undergoing Tonsillectomy: An Updated Meta-Analysis

OBJECTIVE

There is controversy regarding the efficacy and safety of tranexamic acid (TXA) in reducing tonsillectomy-related hemorrhage. We conducted a systematic review and meta-analysis to evaluate the prophylactic role of TXA in tonsillectomy.

METHODS

We searched 6 databases to identify studies that directly compare the effect of TXA versus controls in tonsillectomy patients. Standardized mean difference was applied to summate the findings across the studies. Dichotomous data were expressed as relative risk.

RESULTS

Ten studies representing a total of 111 898 patients were included. The pooled results showed a significant reduction of intraoperative blood loss by 39.02 ml (SMD = -1.05, 95% CI: -1.91 to -0.20, P = .016) and the rate of post-tonsillectomy hemorrhage (RR = 0.42, 95% CI: 0.28 to 0.65, P < .0001), with no significant difference in reduction of further intervention risk (RR = 0.78, 95% CI: 0.45 to 1.35, P = .373).

CONCLUSIONS

Overall, this study indicates that TXA may reduce blood loss and frequency of post-operative hemorrhage associated with tonsillectomy. Further large, high-quality clinical trials are still needed to explore TXA's effect on post-tonsillectomy hemorrhage and the safety of its use.

Aprotinin Inhibits Thrombin Generation by Inhibition of the Intrinsic Pathway, but is not a Direct Thrombin Inhibitor

Background  Aprotinin is a broad-acting serine protease inhibitor that has been clinically used to prevent blood loss during major surgical procedures including cardiac surgery and liver transplantation. The prohemostatic properties of aprotinin likely are related to its antifibrinolytic effects, but other mechanisms including preservation of platelet function have been proposed.

Aim  Here we assessed effects of aprotinin on various hemostatic pathways in vitro, and compared effects to tranexamic acid(TXA), which is an antifibrinolytic but not a serine protease inhibitor.

Methods  We used plasma-based clot lysis assays, clotting assays in whole blood, plasma, and using purified proteins, and platelet activation assays to which aprotinin or TXA were added in pharmacological concentrations.

Results  Aprotinin and TXA dose-dependently inhibited fibrinolysis in plasma. Aprotinin inhibited clot formation and thrombin generation initiated via the intrinsic pathway, but had no effect on reactions initiated by tissue factor. However, in the presence of thrombomodulin, aprotinin enhanced thrombin generation in reactions started by tissue factor. TXA had no effect on coagulation. Aprotinin did not inhibit thrombin, only weakly inhibited the TF-VIIa complex and had no effect on platelet activation and aggregation by various agonists including thrombin. Aprotinin and TXA inhibited plasmin-induced platelet activation.

Conclusion  Pharmacologically relevant concentrations of aprotinin inhibit coagulation initiated via the intrinsic pathway. The antifibrinolytic activity of aprotinin likely explains the prohemostatic effects of aprotinin during surgical procedures. The anticoagulant properties may be beneficial during surgical procedures in which pathological activation of the intrinsic pathway, for example by extracorporeal circuits, occurs.

Approaches to Assessing the Quality of Observational Studies of Clinical Practice Based on the Big Data Analysis

The article is devoted to the discussion of the problems of assessing the quality of observational studies in real clinical practice and determining their place in the hierarchy of evidence-based information. The concept of “big data” and the acceptability of using such a term to refer to large observational studies is being discussed. Data on the limitations of administrative and claims databases when performing observational studies to assess the effects of interventions are presented. The concept of confounding factors influencing the results of observational studies is discussed. Modern approaches to reducing the severity of bias in real-life clinical practice studies are presented. The criteria for assessing the quality of observational pharmacoepidemiological studies and the fundamental differences between such studies and randomized clinical trials are presented. The results of systematic reviews of real-life clinical trials to assess the effects of direct oral anticoagulants are discussed.

 

Population Pharmacokinetics of Intra-articular and Intravenous Administration of Tranexamic Acid in Patients Undergoing Total Knee Replacement

BACKGROUND

Tranexamic acid (TXA), an antifibrinolytic drug, is usually administered intravenously; however, intra-articular administration has recently been proven to be as effective as intravenous administration. Limited information regarding the pharmacokinetics (PK) of TXA after intra-articular administration has been reported.

AIMS

The aim of this study was to develop a population PK model of TXA administered as a single intra-articular dose and as two intravenous doses, and to study the sources of interindividual variability (IIV) in the PK processes of TXA. The developed model was used to simulate PK profiles of TXA at different dosage regimens and in patients with renal impairment.

METHODS

Patients who underwent primary unilateral total knee replacement (TKR) received 1 g/10 mL (concentration of 100 mg/mL) of TXA applied directly to the surgical field before wound closure, or 2 g (two doses of 1 g) of intravenous TXA. A population PK model was developed using a nonlinear mixed-effects approach and sources of IIV, such as sex, age, body weight, height, body mass index (BMI), preoperative haemoglobin, preoperative haematocrit, and creatinine clearance.

RESULTS

Twenty-four patients were included, 12 in each group. Twenty patients were female, mean age (standard deviation) was 73.7 years (5.6). The disposition of TXA was best described as a two-compartment model with clearance dependent on creatinine clearance. Bootstrap results indicated that the model was stable and robust. The estimated bioavailability for intra-articular administration was 81%. Simulations indicated that 100% of patients would have plasma concentrations associated with partial fibrinolysis at 8 h post-administration with the dosages and routes of administration used in the present study. Intra-articular administration would produce complete inhibition of fibrinolysis in only 12% of patients compared with 72.5% with intravenous administration. No adverse events were reported.

CONCLUSIONS

This population PK model demonstrated that a single dose of high-concentration, low-volume intra-articular TXA can achieve antifibrinolytic plasma concentrations of the drug for 8 h, providing both local and systemic effects in patients undergoing TKR. TXA administration to the surgical field could be an alternative to the intravenous; route for patients undergoing TKR; however, clinical studies are needed to assess the toxic local effects of TXA.

TRIAL REGISTRATION

Spanish Clinical Studies Registry Number: 2017-004059-22. Date of registration: 12 April 2018.

Cardiovascular Safety and Superiority of Anti-Obesity Medications

Over the past few decades, several anti-obesity medications have demonstrated an association with adverse cardiovascular outcomes, leading to their market withdrawal. This has caused researchers to investigate the cardiovascular safety of such medications in cardiovascular outcome trials. However, the data from these trials are limited, and their outcomes are not promising. Therefore, the aim of this review is to provide an overview of the current and past Food and Drug Administration-approved medications for weight loss, including novel diabetes medications (glucagon-like peptide 1 receptor agonists and sodium-glucose co-transporter-2 inhibitors) and non-diabetes medications, and to highlight the current designs of cardiovascular outcome trials and their importance in the evaluation of the overall safety concerns associated with these anti-obesity medications. The limitations of the trials and opportunities for improvement were also evaluated. Finally, we also briefly describe cardiovascular safety and risks in this review.

Efficacy and Safety of Antifibrinolytic Drugs in Pediatric Surgery: A Systematic Review

Antifibrinolytic drugs are used to reduce blood loss and subsequent transfusions during surgery and following trauma, but the optimal dosing regimen in the pediatric population is still unresolved. The aim of this systematic review was to evaluate efficacy and safety of antifibrinolytic drugs in pediatric surgery and trauma to determine the optimal dosing regimen. A literature search was performed in PubMed, Embase, Cochrane, and Web of Science on May 3, 2020. We included randomized controlled studies investigating the effect of tranexamic acid (TXA), aprotinin, and epsilon-aminocaproic acid, in terms of reducing blood loss, blood transfusions, reoperations, and rebleeds in pediatric patients aged 0 to 18 years undergoing cardiac surgery, noncardiac surgery, or trauma. Fifty randomized controlled trials (RCTs) were included; 28 RCTs investigated cardiac surgery and 22 investigated noncardiac surgery. No RCTs regarding trauma met the inclusion criteria. All antifibrinolytic drugs reduced postoperative blood loss and transfusions when used in pediatric surgery. The dosing regimen varied between studies, but similar effect sizes were found in terms of reduced blood loss regardless of the cumulative dose used. Few studies found adverse events, and no difference in incidence or type of adverse events was seen between the antifibrinolytic and the placebo group. In conclusion, use of antifibrinolytics is efficient and safe in children undergoing surgery. We propose TXA as the drug of choice based on its level of evidence and safety profile; we recommend a dosing regimen composed of a loading dose of 10 to 15 mg/kg prior to surgery followed by 1 to 5 mg/kg/h as continuous infusion throughout surgery.

Tranexamic acid and obstetric hemorrhage: give empirically or selectively?

Antifibrinolytic agents such as tranexamic acid (TXA) inhibit the fibrinolytic pathway and protect blood clots from being degraded, thereby promoting hemostasis. They have been used to reduce blood loss in various settings including obstetrics. Based on current evidence, TXA can be considered as a therapeutic adjunct to control postpartum hemorrhage (PPH) after vaginal and cesarean deliveries, with earlier administration preferred. This strategy has been demonstrated to reduce mortality due to bleeding (but not the incidence of transfusion) in developing countries. On the other hand, the benefit-risk ratio of TXA has not been fully assessed in developed countries which have much lower PPH-related mortality rates and better access to other management modalities. As a proposed prophylactic agent to prevent PPH, the level of evidence is currently insufficient to recommend the routine use of TXA to prevent blood loss after vaginal and cesarean deliveries. The results of large new multicenter studies assessing the impact of TXA on maternal blood loss-related outcomes after cesarean delivery are awaited. While most studies to date have focused on empirical and one-size-fit-all dosing of TXA, more selective and individualized treatment protocols (possibly guided by functional coagulation assays) are needed to pave the way for safer and more effective use of this inexpensive and widely used medication.

Efficacy of antifibrinolytics in reducing blood loss during hip reconstruction surgery in cerebral palsy children. A systematic review and meta-analysis

BACKGROUND

Cerebral palsy (CP) children undergoing hip reconstruction are more prone to blood loss during surgery due to poor nutritional status, antiepileptic medication intake, depletion of clotting factors, and the extent of surgery involved. We conducted this present review to analyze whether antifibrinolytics during hip surgery in CP children would reduce surgical blood loss and transfusion requirements.

METHODS

Three databases (PubMed, EMBASE, and Cochrane library) were searched independently for publications mentioning the use of antifibrinolytics during hip reconstruction surgery in CP children. The primary outcome was to compare the surgical blood loss with and without antifibrinolytics use. Secondary outcomes were transfusion requirements, drop in hemoglobin level, length of hospital stay, and complication rates.

RESULTS

All five studies (reporting 478 patients) published on this topic were found eligible based on inclusion criteria and were included for final analysis. Primary outcome: In three of the included studies, antifibrinolytics use resulted in a significant reduction in total blood loss with a mean difference (MD) of -151.05 mL (95% CI -272.30 to -29.80, p = 0.01). In the other two studies although statistically not significant, antifibrinolytics use reduces estimated blood loss (MD: 3.27, 95% CI -21.44 to 14.91, p = 0.72). Secondary outcomes: We observed that in the antifibrinolytics group, there was a reduction in total blood transfusion requirements (OD: 0.70, 95% CI 0.35 to 1.37, p = 0.29), and a drop in haemoglobin level (MD: 0.16, 95% CI -0.62 to 0.30, p = 0.49) but statistically not significant. No adverse effects related directly to antifibrinolytics were noticed in all five studies.

CONCLUSION

Only two out of five included studies favored the use of antifibrinolytics in CP children undergoing hip reconstruction. The evidence synthesized on this meta-analysis is also not sufficient enough to support its routine use in this cohort of children for hip reconstruction surgery. High-quality studies with adequate sample size to determine the effective and safe dosage, timing, and cost involved of different antifibrinolytics are the need of the hour.

LEVEL OF EVIDENCE

Ⅲ.

Preservation of renal endothelial integrity and reduction of renal edema by aprotinin does not preserve renal perfusion and function following experimental cardiopulmonary bypass

BACKGROUND

Acute kidney injury is a severe complication following cardiopulmonary bypass (CPB) and is associated with capillary leakage and microcirculatory perfusion disturbances. CPB-induced thrombin release results in capillary hyperpermeability via activation of protease-activated receptor 1 (PAR1). We investigated whether aprotinin, which is thought to prevent thrombin from activating PAR1, preserves renal endothelial structure, reduces renal edema and preserves renal perfusion and reduces renal injury following CPB.

METHODS

Rats were subjected to CPB after treatment with 33.000 KIU/kg aprotinin (n = 15) or PBS (n = 15) as control. A secondary dose of 33.000 KIU/kg aprotinin was given 60 min after initiation of CPB. Cremaster and renal microcirculatory perfusion were assessed using intravital microscopy and contrast echography before CPB and 10 and 60 min after weaning from CPB. Renal edema was determined by wet/dry weight ratio and renal endothelial structure by electron microscopy. Renal PAR1 gene and protein expression and markers of renal injury were determined.

RESULTS

CPB reduced cremaster microcirculatory perfusion by 2.5-fold (15 (10-16) to 6 (2-10) perfused microvessels, p < 0.0001) and renal perfusion by 1.6-fold (202 (67-599) to 129 (31-292) au/sec, p = 0.03) in control animals. Both did not restore 60 min post-CPB. This was paralleled by increased plasma creatinine (p < 0.01), neutrophil gelatinase-associated lipocalin (NGAL; p = 0.003) and kidney injury molecule-1 (KIM-1; p < 0.01). Aprotinin treatment preserved cremaster microcirculatory perfusion following CPB (12 (7-15) vs. 6 (2-10) perfused microvessels, p = 0.002), but not renal perfusion (96 (35-313) vs. 129 (31-292) au/s, p > 0.9) compared to untreated rats. Aprotinin treatment reduced endothelial gap formation (0.5 ± 0.5 vs. 3.1 ± 1.4 gaps, p < 0.0001), kidney wet/dry weight ratio (4.6 ± 0.2 vs. 4.4 ± 0.2, p = 0.046), and fluid requirements (3.9 ± 3.3 vs. 7.5 ± 3.0 ml, p = 0.006) compared to untreated rats. In addition, aprotinin treatment reduced tubulointerstitial neutrophil influx by 1.7-fold compared to untreated rats (30.7 ± 22.1 vs. 53.2 ± 17.2 neutrophil influx/section, p = 0.009). No differences were observed in renal PAR1 expression and plasma creatinine, NGAL or KIM-1 between groups.

CONCLUSIONS

Aprotinin did not improve renal perfusion nor reduce renal injury during the first hour following experimental CPB despite preservation of renal endothelial integrity and reduction of renal edema.

Impact of ABO blood group on bleeding complications after surgery for acute type A aortic dissection

Excessive bleeding is a serious complication associated with impaired survival after surgery for acute type A aortic dissection (ATAAD). Different ABO blood groups are associated with variable levels of circulating von Willebrand factor and therefore potentially altered risks of surgical haemorrhage. The current study aimed to assess the impact of blood group on bleeding complications after ATAAD surgery. This was a retrospective cohort study including 336 patients surgically treated for ATAAD between January 2004 and January 2019. Patients with blood group O were compared with non-O patients. In total, 152 blood group O patients were compared with 184 non-O patients. There were no differences in rates of massive bleeding (27.0 vs. 25.5%, P = 0.767) or re-exploration for bleeding (16.4 vs. 13.0%, P = 0.379) in blood group O and non-O patients, respectively. Median chest tube output 12 h after surgery was 520 ml (350-815 ml) in blood group O and 490 ml (278-703 ml) in non-O patients (P = 0.229). Blood group O patients received more fibrinogen concentrate (6.1 ± 4.0 vs. 4.9 ± 3.3 g, P = 0.023) but administered units of packed red blood cells [5 (2-8) vs. 4 (2-9) U, P = 0.736], platelets [4 (2-4) vs. 3 (2-5) U, P = 0.521] or plasma [4 (1-7) vs. 4 (0-7) U, P = 0.562] were similar. This study could not demonstrate any association between blood group and bleeding after surgery for ATAAD. It cannot be ruled out that potential differences were levelled out by blood group O patients receiving significantly more fibrinogen concentrate.

Trypsin-Like Proteases and Their Role in Muco-Obstructive Lung Diseases

Trypsin-like proteases (TLPs) belong to a family of serine enzymes with primary substrate specificities for the basic residues, lysine and arginine, in the P1 position. Whilst initially perceived as soluble enzymes that are extracellularly secreted, a number of novel TLPs that are anchored in the cell membrane have since been discovered. Muco-obstructive lung diseases (MucOLDs) are characterised by the accumulation of hyper-concentrated mucus in the small airways, leading to persistent inflammation, infection and dysregulated protease activity. Although neutrophilic serine proteases, particularly neutrophil elastase, have been implicated in the propagation of inflammation and local tissue destruction, it is likely that the serine TLPs also contribute to various disease-relevant processes given the roles that a number of these enzymes play in the activation of both the epithelial sodium channel (ENaC) and protease-activated receptor 2 (PAR2). More recently, significant attention has focused on the activation of viruses such as SARS-CoV-2 by host TLPs. The purpose of this review was to highlight key TLPs linked to the activation of ENaC and PAR2 and their association with airway dehydration and inflammatory signalling pathways, respectively. The role of TLPs in viral infectivity will also be discussed in the context of the inhibition of TLP activities and the potential of these proteases as therapeutic targets.

Antifibrinolytics reduces blood loss in thoracic surgery: a systematic review and meta-analysis

BACKGROUND

The purpose of this systematic review is to evaluate the efficacy of antifibrinolytics in non-cardiac thoracic surgery.

METHODS

We searched for all randomized controlled trials on this topic. A set of strict inclusion and exclusion criteria was developed. Six studies were meta-analysed together then in subgroups of topical tranexamic acid and intravenous aprotinin. We compared postoperative chest drain output, transfusions requirements and duration of hospital stay where available to determine the efficacy of topical tranexamic acid or intravenous aprotinin in reducing blood loss.

RESULTS

The use of antifibrinolytics reduces 24-h chest drain output (-290.21 mL [-524.75, -55.66], P = 0.02, I²  = 98%), red blood cell transfusion requirements (-1.27 units [-2.24, -0.30], P = 0.01, I²  = 100%) and shortened duration of hospital stay (-1.81 days [-3.25, -0.36], P = 0.01, I²  = 96%). The subgroup analysis also supported this trend.

CONCLUSION

We conclude that the use of antifibrinolytics appears to reduce postoperative blood loss by reducing chest drain output, transfusion requirements and length of stay after thoracic surgery.

A survey of patient blood management for patients undergoing cardiac surgery in nine European countries

STUDY OBJECTIVE

To describe and compare patient blood management (PBM) practices in cardiac surgery in nine European countries and identify the main risk factors for bleeding or transfusion according to the surveyed centres.

DESIGN

We set up an online survey to evaluate PBM practices in two clinical scenarios, risk factors for bleeding or transfusion, and previous experience with antifibrinolytics.

SETTING

This survey was completed by European anesthesiologists in 2019.

PATIENTS

No patients were included in the survey.

INTERVENTION

None.

MEASUREMENTS

We evaluated the degree of implementation of PBM practices in patients undergoing cardiac surgery.

MAIN RESULTS

Ninety-eight of 177 responses (38%) were complete with variable response rates by country. In a non-emergent situation, no respondents would transfuse red cells preoperatively in an anaemic patient, while cell salvage (89%) and antifibrinolytics (82%) would almost always be used. Optimization of Hemoglobin level (36%) and use of off-pump techniques (34%), minimally invasive surgery (25%) and relatively recently-developed CPB technologies such as mini-bypass (32%) and autologous priming (38%), varied greatly across countries. In an emergent clinical situation, topical haemostatic agents would frequently be used (61%). Tranexamic acid (72%) and aprotinin (20%) were the main antifibrinolytics used, with method of administration and dose varying markedly across countries. Five factors were considered to increase risk of bleeding or transfusion by at least 90% of respondents: pre-operative anaemia, prior cardiac surgery, clopidogrel 5 days or less before surgery, use of other P2Y12 inhibitors at any point, and thrombocytopenia <100.10⁹ platelets/mm³.

CONCLUSION

PBM guidelines are not universally implemented in European cardiac surgery centres or countries, resulting in discrepancies in techniques and products used for a given clinical situation.

Fibrinolysis in Patients with Liver Disease

Patients with liver disease acquire complex changes in their hemostatic system. Historically, these patients were considered to have a bleeding tendency related, in part, to a hyperfibrinolytic state. However, studies using more modern fibrinolysis tests have questioned the presence of a hyperfibrinolytic state in patients with liver disease and its association with bleeding risk. It may be that the sickest patients with liver disease do have fibrinolytic abnormalities. However, the debate on the fibrinolytic state of patients with (decompensated) cirrhosis or critically ill liver disease is complicated by the fact that hypo- and hyperfibrinolysis have been poorly defined. This could, in part, be explained by the lack of reliable tests that assess a patient's fibrinolytic status. Moreover, large clinical studies on the relationship between bleeding and fibrinolysis in patients with liver disease are scarce. Here, we provide an overview of the current knowledge on fibrinolysis in various types of liver diseases and possible implications as a target for therapeutic strategies in liver disease. As antifibrinolytic therapy has been shown to be safe and effective during liver transplantation, it could potentially be of use in patients with (either laboratory-established or suspected) hyperfibrinolysis-related bleeding.

A Systematic Review of Tranexamic Acid in Plastic Surgery: What's New?

BACKGROUND

Blood loss associated with surgical interventions can lead to several complications. Therefore, minimizing perioperative bleeding is critical to improve overall survival. Several interventions have been found to successfully reduce surgical bleeding, including the antifibrinolytic agent. After aprotinin was withdrawn from the market in 2008, TXA remained the most commonly used medication. The safety and efficacy of TXA has been well studied in other specialties. TXA has been rarely used in plastic surgery, except in craniofacial procedures. Since the last review, the number of articles examining the use of TXA has doubled; so the aim of this systematic review is to update the readers on the current knowledge and clinical recommendations regarding the efficacy of TXA in plastic surgical procedures.

METHODS

A systematic literature search was conducted in Medline, SciELO, Cochrane, and Google Scholar to evaluate all articles that discussed the use of TXA in plastic surgery in the fields of aesthetic surgery, burn care, and reconstructive microsurgery.

RESULTS

A total of 233 publications were identified using the search criteria defined above. After examination of titles and abstracts, and exclusion of duplicates, a total of 23 articles were selected for analysis.

CONCLUSIONS

The literature shows a clear benefit of using TXA to decrease blood loss regardless of the administration route, with no risk of thrombosis events. Also, TXA elicits a potent anti-inflammatory response with a decrease in postoperative edema and ecchymosis, which improves recovery time. Further investigations are needed to standardize the optimal administration route and dosage of TXA.

Food and Drug Administration Beyond the 2001 Government Accountability Office Report: Promoting Drug Safety for Women

A 2001 U.S. Government Accountability Office (GAO) report indicated 8 of 10 drugs withdrawn from the U.S. market between 1997 and 2000 posed greater risk to women than men. We examined drugs withdrawn from the market for safety-related reasons from January 1, 2001, to January 1, 2018. To be included, drugs must be listed as discontinued on Drugs@FDA and either listed in the Federal Register or cited in literature as being withdrawn for safety-related reasons. Biologics, over-the-counter products, and medical devices were excluded. During the 17-year time span, 19 drugs were withdrawn from the market for safety-related reasons, fewer drugs per year compared to the 3-year period examined in the GAO report. Food and Drug Administration (FDA) has not recommended the market removal of any drug approved since 2005 due to the time from the start of the Q wave to the end of the T wave (QT) interval prolongation resulting in torsades de pointes (TdP) or other abnormal heart rhythms. Furthermore, no drugs approved after the implementation of FDA's 2009 guidance on drug-induced liver injury (DILI) have been withdrawn because of hepatoxicity. All, but one of the drugs discontinued from the market for safety-related reasons during the period examined were approved between 1957 and 2002. TdP and DILI are two relevant examples of drug-induced adverse events posing greater risk to women than men. FDA has made measurable progress incorporating consideration of sex and gender differences into drug trial development and FDA review of these data, supporting inclusion of women in clinical trials, providing a comprehensive drug safety review, and advancing postmarket surveillance and risk assessment, thus strengthening FDA's ability to protect public health.

Exposure-Response Relationship of Tranexamic Acid in Cardiac Surgery

BACKGROUND

It is unclear whether high-dose regimens of tranexamic acid in cardiac surgery (total dose, 80 to 100 mg/kg) confer a clinical advantage over low-dose regimens (total dose, approximately 20 mg/kg), particularly as tranexamic acid-associated seizure may be dose-related. The authors' aim was to characterize the exposure-response relationship of this drug.

METHODS

Databases were searched for randomized controlled trials of intravenous tranexamic acid in adult patients undergoing cardiopulmonary bypass surgery. Observational studies were added for seizure assessment. Tranexamic acid concentrations were predicted in each arm of each study using a population pharmacokinetic model. The exposure-response relationship was evaluated by performing a model-based meta-analysis using nonlinear mixed-effect models.

RESULTS

Sixty-four randomized controlled trials and 18 observational studies (49,817 patients) were included. Seventy-three different regimens of tranexamic acid were identified, with the total dose administered ranging from 5.5 mg/kg to 20 g. The maximum effect of tranexamic acid for postoperative blood loss reduction was 40% (95% credible interval, 34 to 47%), and the EC50 was 5.6 mg/l (95% credible interval, 0.7 to 11 mg/l). Exposure values with low-dose regimens approached the 80% effective concentration, whereas with high-dose regimens, they exceeded the 90% effective concentration. The predicted cumulative blood loss up to 48 h postsurgery differed by 58 ml between the two regimens, and the absolute difference in erythrocyte transfusion rate was 2%. Compared to no tranexamic acid, low-dose and high-dose regimens increased the risk of seizure by 1.2-fold and 2-fold, respectively. However, the absolute risk increase was only clinically meaningful in the context of prolonged open-chamber surgery.

CONCLUSIONS

In cardiopulmonary bypass surgery, low-dose tranexamic acid seems to be an appropriate regimen for reducing bleeding outcomes. This meta-analysis has to be interpreted with caution because the results are observational and dependent on the lack of bias of the predicted tranexamic acid exposures and the quality of the included studies.

EDITOR’S PERSPECTIVE

Do all cardiac surgery patients benefit from antifibrinolytic therapy?

BACKGROUND

In trauma patients, the recognition of fibrinolysis phenotypes has led to a re-evaluation of the risks and benefits of antifibrinolytic therapy (AF). Many cardiac patients also receive AF, but the distribution of fibrinolytic phenotypes in that population is unknown. The purpose of this hypothesis-generating study was to fill that gap.

METHODS

Seventy-eight cardiac surgery patients were retrospectively reviewed. Phenotypes were defined as hypofibrinolytic (LY30 <0.8%), physiologic (0.8%-3.0%), and hyperfibrinolytic (>3%) based on thromboelastogram.

RESULTS

The population was 65 ± 10-years old, 74% male, average body mass index of 29 ± 5 kg/m² . Fibrinolytic phenotypes were distributed as physiologic = 45% (35 of 78), hypo = 32% (25 of 78), and hyper = 23% (18 of 78). There was no obvious effect of age, gender, race, or ethnicity on this distribution; 47% received AF. For AF versus no AF, the time with chest tube was longer (4 [1] vs. 3 [1] days, p = .037), and all-cause morbidity was more prevalent (51% vs. 25%, p = .017). However, when these two groups were further stratified by phenotypes, there were within-group differences in the percentage of patients with congestive heart failure (p = .022), valve disease (p = .024), on-pump surgery (p < .0001), estimated blood loss during surgery (p = .015), transfusion requirement (p = .015), and chest tube output (p = .008), which highlight other factors along with AF that might have affected all-cause morbidity.

CONCLUSION

This is the first description of the prevalence of three different fibrinolytic phenotypes and their potential influence on cardiac surgery patients. The use of AF was associated with increased morbidity, but because of the small sample size and treatment allocation bias, additional confirmatory studies are necessary. We hope these present findings open the dialog on whether it is safe to administer AFs to cardiac surgery patients who are normo- or hypofibrinolytic.

Blood cell adhesion to arterial filters analysis by scanning electron microscopy and real-time PCR assay: observational clinical study in cardiac surgery patients

INTRODUCTION

Arterial filter is the part of the cardiopulmonary bypass circuit where blood cells are exposed to high mechanical stress and where cellular aggregates may fasten in large quantities. The aim of this study was to analyse blood cell adhesiveness in the arterial filter through scanning electron microscopy and real-time PCR assay.

METHODS

Prospective, clinical and observational study performed on 28 patients undergoing cardiac surgery with cardiopulmonary bypass. Arterial filters were analysed by scanning electron microscopy. Real-time PCR assay was performed in extracted material from the arterial filters for analysis of platelet GPIb and CD45 leucocyte gene expression. Blood coagulation was analysed during cardiopulmonary bypass. Patients were followed until hospital discharge or 28 days after surgery.

RESULTS

All studied arterial filters used in the subject patients showed a degree of adhesion from blood elements at scanning electron microscopy. All studied filters were positive for platelets GPIb gene expression and 15% had CD45 leucocyte gene expression. The GPIb platelet gene expression in blood lowered at the end of cardiopulmonary bypass (p = 0.019). There was negative correlation between blood GPIb platelet gene expression and Clot SR (HEPSCREEN2 ReoRox^®) (rho = 0.635; p = 0.027). The filter fields count was correlated to the D-dimer dosage (rho = 0.828; p < 0.001).

CONCLUSION

There was adhesion of blood elements, especially nucleated platelets, on all arterial filters studied. Although the arterial filter worked as a safety device, that possibly prevented arterial embolisation, it may also have caused greater hyperfibrinolysis during cardiopulmonary bypass.

Efficacy of Topical Tranexamic Acid (Cyclokapron) in "Wet" Field Infiltration with Dilute Local Anaesthetic Solutions in Plastic Surgery

BACKGROUND

Surgical bleeding may lead to the need for blood transfusion and minimizing blood loss has been a basic principle followed by surgeons for generations. Antifibrinolytic agents are widely used to reduce perioperative haemorrhage. The present study sought to assess the efficacy of directly infiltrated tranexamic acid in ameliorating bruising in participants undergoing cosmetic plastic surgery (liposuction).

MATERIALS AND METHODS

The study employed a blinded, prospective, randomized, case control design. Thirty-three patients were studied. Tranexamic acid free infiltration tumescent solution (saline, bupivacaine lignocaine and adrenalin) was infiltrated to one flank of patients undergoing liposuction of flanks. The other flank was infiltrated with the same tumescent solution (saline, bupivacaine lignocaine and adrenalin) mixed with tranexamic acid (0.1%). Bruises were photographed one and seven days after surgery and measured for size. The surface area of the bruises was calculated using ImageJ software. We compared the bruised surface are between the tranexamic acid infiltrated flank and non-tranexamic acid infiltrated flank in the same patient. The model employed involved measuring the bruises on each flank of the same patient, with surgery by a single surgeon using the same infiltration and surgical techniques for both sides. The only variable was the difference in tranexamic acid concentration between study and control flanks.

RESULTS

We found that use of tranexamic acid consistently resulted in a smaller bruise area on days one and seven after liposuction of flanks. Results were statistically significant.

CONCLUSIONS

This is the first study examining addition of tranexamic acid to a tumescent infiltration solution-to produce a predictable local concentration of tranexamic acid-in order to maximize surgical site effect and minimize systemic effect. The authors recommend incorporation of tranexamic acid as a routine component along with adrenaline and local anaesthetics in tumescent field infiltration solution 10-15 min before commencement of the cosmetic surgery.

LEVEL OF EVIDENCE II

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The impact of tranexamic acid on administration of red blood cell transfusions for resection of colorectal liver metastases

BACKGROUND

Red blood cell transfusions (RBCT) remain a concern for patients undergoing hepatectomy. The effect of tranexamic acid (TXA), an anti-fibrinolytic, on receipt of RBCT in colorectal liver metastases (CRLM) resection was examined.

METHODS

Hepatectomies for CRLM over 2009-2014 were included. Primary outcome was 30-day receipt of RBCT. Secondary outcomes were 30-day major morbidity (Clavien-Dindo III-V) and 90-day mortality. Multivariable modelling examined the adjusted association between TXA and outcomes.

RESULTS

Of 433 included patients, 146 (34%) received TXA. TXA patients were more likely to have inflow occlusion (41.8% vs. 23.1%; p < 0.01) and major hepatectomies (56.1% vs. 45.6%; p = 0.0193). TXA was independently associated with lower risk of RBCT (Relative risk (RR) 0.59; 95% confidence interval (95%CI): 0.42-0.85), but not with 30-day major morbidity (adjusted RR 1.02; 95%CI: 0.64-1.60) and 90-day mortality (univariable RR 0.99; 95%CI: 0.95-1.03).

CONCLUSION

Intraoperative TXA was associated with a 41% reduction in risk of 30 -day receipt of RBCT after hepatectomy for CRLM. This finding is important to potentially improve healthcare resource allocation and patient outcomes. Pending further evidence, intraoperative TXA may be an effective method of reducing RBCT in hepatectomy for CRLM.