Safety and Efficacy of Aprotinin and Tranexamic Acid in Pulmonary Endarterectomy Surgery With Hypothermia: Review of 200 Patients

Pulmonary thromboendarterectomy-the Royal Papworth experience

BACKGROUND

Pulmonary thromboendarterectomy (PTE) was first introduced to the UK 25 years ago, and the UK national service is provided by a single hospital. The aim of this work is to summarize our experience and review activity and outcomes by era at a high-volume PTE center. During this period the understanding of chronic thromboembolic pulmonary hypertension (CTEPH) increased and drug treatments and balloon angioplasty were developed. We also review our contribution to the better understanding of this surgery and CTEPH.

METHODS

We retrospectively reviewed all patients undergoing PTE for CTEPH at our center between Jan 1997 and Sept 2019, dividing them into four equal cohorts. Pre-operative characteristics and post-operative outcomes are described by era. A MEDLINE search was performed and original scientific clinical publications from this unit were reviewed. Their contemporary relevance and influence to the evolution of the clinical service are discussed.

RESULTS

Over this 23-year period from the commencement of our program, 2,116 consecutive PTE were performed. The mean patient age was 57.8 years (range, 11-89 years). The first 25% of our PTE were performed over 12 years whilst the most recent 25% were performed in less than three years. Over time, the average pre-operative mean pulmonary artery pressure has not changed significantly. The 30-day mortality by era quartile has progressively fallen from 12.3% to 1.9% most recently (P<0.001). Overall, one year survival exceeded 90%. 17 publications influenced our practice development during this period.

CONCLUSIONS

There was a consistent increase in activity and significant improvement in outcomes between the first and last quartiles of activity studied.

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.

Does tranexamic acid reduce risk of mortality on patients with hemoptysis?: A protocol for systematic review and meta-analysis

BACKGROUND

Although tranexamic acid (TXA), a readily accessible antifibrinolytic agent, is widely adopted in hemorrhage scenarios, its role on mortality in patients with hemoptysis remains uncertain. New evidence is yet to be generated to evaluate the risk of mortality after using TXA in patients with hemoptysis.

METHODS

PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases were searched from inception to May 2020. Randomized controlled trials and observational studies that evaluated the effect of TXA on patients with hemoptysis were included. Data were independently extracted by 2 reviewers and synthesized using a random-effects model.

MAIN RESULTS

Five studies with a total of 20,047 patients were analyzed. When compared with the control, administration of TXA was associated with a reduction in short-term mortality (risk ratio = 0.78, 95% confidence interval [CI] 0.72-0.85; I2 = 0), shorter bleeding time (mean difference = - 24.61 hours, 95% CI - 35.96 to -13.26, I2 = 0), shorter length of hospital stay (mean difference = -1.94 days, 95% CI -2.48 to -1.40, I2 = 0), and lower need for intervention (risk ratio = 0.38, 95% CI 0.16-0.87, I2 = 0) in patients with hemoptysis. Compared with control, administration of TXA did not cause increased major or minor adverse effects.

CONCLUSIONS

TXA provided benefits in terms of a lower short-term mortality rate, less bleeding time, shorter length of hospital stays, and less need for intervention in patients with hemoptysis. Use of TXA was not associated with increased adverse effects.

[Progress on the application of tranexamic acid in adolescent spine corrective surgery]

Objective

To review the advances in the application of tranexamic acid (TXA) in adolescent spinal corrective surgery.

Methods

The mechanism of action and pharmacokinetic, effectiveness, dosage, safety as well as methods of administration were comprehensively summarized by consulting domestic and overseas related literature about the application of TXA in adolescent spinal corrective surgery in recent years.

Results

TXA efficaciously reduce intraoperative blood loss, transfusion rate and volume, postoperative drainage volume in adolescent spinal corrective surgery. At present, the most common method of administration in adolescent spinal corrective surgery is that a loading dose is given intravenously before skin incision or induction of anesthesia, followed by a maintenance dose until the end of the surgery. The range of loading dose and maintenance dose is 10-100 mg/kg and 1-10 mg/(kg·h), respectively. No drug related adverse event has been reported in this range.

Conclusion

The effectiveness and safety of TXA in adolescent spinal surgery have been basically confirmed. However, further studies are needed to determine the optimal dosage, method of administration as well as whether it could reduce blood loss after surgery.

Termination of bleeding by a specific, anticatalytic antibody against plasmin

BACKGROUND

Excessive, plasmin-mediated fibrinolysis augments bleeding and contributes to death in some patients. Current therapies for fibrinolytic bleeding are limited by modest efficacy, low potency, and off-target effects.

OBJECTIVES

To determine whether an antibody directed against unique loop structures of the plasmin protease domain may have enhanced specificity and potency for blocking plasmin activity, fibrinolysis, and experimental hemorrhage.

METHODS

The binding specificity, affinity, protease cross-reactivity and antifibrinolytic properties of a monoclonal plasmin inhibitor antibody (Pi) were examined and compared with those of epsilon aminocaproic acid (EACA), which is a clinically used fibrinolysis inhibitor.

RESULTS

Pi specifically recognized loop 5 of the protease domain, and did not bind to other serine proteases or nine other non-primate plasminogens. Pi was ~7 logs more potent in neutralizing plasmin cleavage of small-molecule substrates and >3 logs more potent in quenching fibrinolysis than EACA. Pi was similarly effective in blocking catalysis of a small-molecule substrate as α2 -antiplasmin, which is the most potent covalent inhibitor of plasmin, and was a more potent fibrinolysis inhibitor. Fab or chimerized Fab fragments of Pi were equivalently effective. In vivo, in a humanized model of fibrinolytic surgical bleeding, Pi significantly reduced bleeding to a greater extent than a clinical dose of EACA.

CONCLUSIONS

A mAb directed against unique loop sequences in the protease domain is a highly specific, potent, competitive plasmin inhibitor that significantly reduces experimental surgical bleeding in vivo.

Tranexamic acid-associated seizures: Causes and treatment

Antifibrinolytic drugs are routinely used worldwide to reduce the bleeding that results from a wide range of hemorrhagic conditions. The most commonly used antifibrinolytic drug, tranexamic acid, is associated with an increased incidence of postoperative seizures. The reported increase in the frequency of seizures is alarming, as these events are associated with adverse neurological outcomes, longer hospital stays, and increased in‐hospital mortality. However, many clinicians are unaware that tranexamic acid causes seizures. The goal of this review is to summarize the incidence, risk factors, and clinical features of these seizures. This review also highlights several clinical and preclinical studies that offer mechanistic insights into the potential causes of and treatments for tranexamic acid–associated seizures. This review will aid the medical community by increasing awareness about tranexamic acid–associated seizures and by translating scientific findings into therapeutic interventions for patients. ANN NEUROL 2016;79:18–26

Cryotherapy on postoperative rehabilitation of joint arthroplasty

PURPOSE

The effectiveness of cryotherapy on joint arthroplasty recovery remains controversial. This systematic review was conducted to assess the effectiveness of cryotherapy in patients after joint arthroplasty.

METHODS

Comprehensive literature searches of several databases including Cochrane Library (2013), MEDLINE (1950-2013), and Embase (1980-2013) were performed. We sought randomised controlled trials that compared the experimental group received any form of cryotherapy with any control group after joint arthroplasty. The main outcomes were postoperative blood loss, adverse events, and pain. Analyses were performed with Revman 5.0. Results were shown as mean differences (MD) and standard deviations or as risk difference and 95 % confidence intervals (CIs).

RESULTS

Ten trials comprised 660 total knee arthroplastys and three trials comprised 122 total hip arthroplastys (THAs) met the inclusion criteria. Blood loss was significantly decreased by cryotherapy (MD = -109.68; 95 % CI -210.92 to -8.44; P = 0.03). Cryotherapy did not increase the risk of adverse effect (n.s.). Cryotherapy decreased pain at the second day of postoperative (MD = -1.32; 95 % CI -2.37 to -0.27; P = 0.0003), but did not decreased pain at the first and third day of postoperative (n.s.).

CONCLUSIONS

Cryotherapy appears effective in these selected patients after joint arthroplasty. The benefits of cryotherapy on blood loss after joint arthroplasty were obvious. However, the subgroup analysis indicated that cryotherapy did not decreased blood loss after THA. Cryotherapy did not increase the risk of adverse effect. Cryotherapy decreased pain at the second day of postoperative, but did not decreased pain at the first and third day of postoperative.

LEVEL OF EVIDENCE

II.

Comparison of Two Doses of Tranexamic Acid in Adults Undergoing Cardiac Surgery with Cardiopulmonary Bypass

Background:

The optimal dose of tranexamic acid (TA) is still an issue. The authors compared two doses of TA during cardiac surgery in a multicenter, double-blinded, randomized study.

Methods:

Patients were stratified according to transfusion risk, then randomized to two TA doses: 10 mg/kg bolus followed by 1 mg·kg−1·h−1 infusion (low dose) until the end of surgery or 30 mg/kg bolus followed by 16 mg·kg−1·h−1 infusion (high dose). The primary endpoint was the incidence of blood product transfusion up to day 7. Secondary ones were incidences of transfusion for each type of blood product and amounts transfused, blood loss, repeat surgery, TA-related adverse events, and mortality.

Results:

The low-dose group comprised 284 patients and the high-dose one 285. The primary endpoint was not significantly different between TA doses (63% for low dose vs. 60% for high dose; P = 0.3). With the high dose, a lower incidence of frozen plasma (18 vs. 26%; P = 0.03) and platelet concentrate (15 vs. 23%; P = 0.02) transfusions, lower amounts of blood products (2.5 ± 0.38 vs. 4.1 ± 0.39; P = 0.02), fresh frozen plasma (0.49 ± 0.14 vs.1.07 ± 0.14; P = 0.02), and platelet concentrates transfused (0.50 ± 0.15 vs. 1.13 ± 0.15; P = 0.02), lower blood loss (590 ± 50.4 vs. 820 ± 50.7; P = 0.01), and less repeat surgery (2.5 vs. 6%; P = 0.01) were observed. These results are more marked in patients with a high risk for transfusion.

Conclusions:

A high dose of TA does not reduce incidence of blood product transfusion up to day 7, but is more effective than a low dose to decrease transfusion needs, blood loss, and repeat surgery.

Comparison of two tranexamic acid dose regimens in patients undergoing cardiac valve surgery

OBJECTIVE

Tranexamic acid (TA), a synthetic antifibrinolytic drug, has been shown to reduce postoperative bleeding and the need for allogeneic blood transfusion in cardiac surgery. However, the optimal dose regimen of TA is still under debate. The aim of this study was to evaluate whether a lower-dose TA regimen produced equivalent efficacy to its higher-dose counterpart in reducing postoperative bleeding and transfusion needs.

DESIGN

A prospective, randomized, double-blind trial.

SETTING

National Center for Cardiovascular Diseases & University Hospital, Beijing, People's Republic of China.

PARTICIPANTS

One hundred seventy-five patients undergoing cardiac valve surgery were enrolled in the study.

INTERVENTIONS

All patients were divided randomly into 2 groups. The lower-dose TA group received a loading dose of 10 mg/kg, maintenance dose of 2 mg/kg/h, and a cardiopulmonary bypass pump prime dose of 40 mg; the higher-dose TA group received a loading dose of 30 mg/kg, maintenance dose of 16 mg/kg/h, and a pump prime dose of 2 mg/kg.

MEASUREMENTS AND MAIN RESULTS

The amount of postoperative bleeding, the amount and frequency of allogeneic transfusion, mortality, and morbidities were recorded. There was no significant difference in the volume of 24-hour postoperative bleeding between the lower-dose group and the higher-dose group. Other measurements also showed no statistical difference between the 2 groups, including the amount and frequency of allogeneic transfusion, mortality, and morbidities.

CONCLUSION

Lower-dose TA regimen was as effective as the higher-dose regimen in reducing postoperative bleeding and transfusion needs in patients undergoing cardiac valve surgery.

Antifibrinolytic agents in current anaesthetic practice

Antifibrinolytic drugs have become almost ubiquitous in their use during major surgery when bleeding is expected or commonplace. Inhibition of the fibrinolytic pathway after tissue injury has been consistently shown to reduce postoperative or traumatic bleeding. There is also some evidence for a reduction of perioperative blood transfusion. However, evidence of complications associated with exaggerated thrombosis also exists, although this appears to be influenced by the choice of the individual agent and the dose administered. There is controversy over the use of the serine protease inhibitor aprotinin, whose license was recently withdrawn but may shortly become available on the market again. In the UK, tranexamic acid, a tissue plasminogen and plasmin inhibitor, is most commonly used, with evidence for benefit in cardiac, orthopaedic, urological, gynaecological, and obstetric surgery. In the USA, ε-aminocaproic acid, which also inhibits plasmin, is commonly used. We have reviewed the current literature for this increasingly popular class of drugs to support clinical judgement in daily anaesthetic practice.

Aprotinin revisited

In 2008, we saw the withdrawal of aprotinin from the US markets after preliminary results from a large, randomized clinical trial in Canada. This drug, a potent antifibrinolytic, was used primarily in complex and/or redo cardiac surgery as an adjunct to decrease postoperative bleeding and complications. The Canadian study raised questions previously brought up in similar studies-does aprotinin increase the risk of mortality and renal failure after cardiac surgery? Recently, a re-review of the Canadian data noted flaws in the study, as well as in the interpretation of the results. The present review revisits the aprotinin controversy.

Strategies to reduce the use of blood products: a US perspective

PURPOSE OF REVIEW

To describe the recent developments in the strategies to reduce allogeneic blood transfusions with emphasis on the impact on clinical outcomes.

RECENT FINDINGS

Concerns over the safety, efficacy, and supply of allogeneic blood continue to necessitate its judicious use as the standard of care. Patient blood management is emerging as a multidisciplinary, multimodality strategy to address anemia and decrease bleeding with the goal of reduced transfusions and improved patient outcomes. Common risk factors for transfusion include anemia, blood loss, and inappropriate transfusion decisions. Several approaches are available to mitigate these. Recent data continue to support the effectiveness of various hematinics, hemostatic agents and devices, as well as intermittent discontinuation of anticoagulant therapy. Use of autotransfusion techniques, particularly cell salvage, is the other strategy with accumulating data supporting its safety and efficacy. Finally, implementation of evidence-based transfusion guidelines will help to target allogeneic blood to those patients who are likely to benefit from it and thus reduce or eliminate unnecessary exposure to blood.

SUMMARY

Patient blood management is the timely use of safe and effective medical and surgical techniques designed to prevent anemia and decrease bleeding in an effort to improve patient outcome.

Use of Topical Tranexamic Acid or Aminocaproic Acid to Prevent Bleeding After Major Surgical Procedures

OBJECTIVE:

To evaluate the literature describing topical use of tranexamic acid or aminocaproic acid for prevention of postoperative bleeding after major surgical procedures.

DATA SOURCES:

Literature was retrieved through MEDLINE (1946-September 2011) and International Pharmaceutical Abstracts(1970-September 2011) using the terms tranexamic acid, aminocaproic acid, antifibrinolytic, topical, and surgical. In addition, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION:

All identified articles in English were evaluated. Clinical trials, case reports, and meta-analyses describing topical use of tranexamic acid or aminocaproic acid to prevent postoperative bleeding were included.

DATA SYNTHESIS:

A total of 16 publications in the setting of major surgical procedures were included; the majority of data were for tranexamic acid. For cardiac surgery, 4 trials used solutions containing tranexamic acid (1-2.5 g in 100-250 mL of 0.9% NaCl), and 1 trial assessed a solution containing aminocaproic acid (24 g in 250 mL of 0.9% NaCl). These solutions were poured into the chest cavity before sternotomy closure. For orthopedic procedures, all of the data were for topical irrigation solutions containing tranexamic acid (500 mg-3 g in 50-100 mL of 0.9% NaCl) or for intraarticular injections of tranexamic acid (250 mg to 2 g in 20-50 mL of 0.9% sodium chloride, with or without carbazochrome sodium sulfate). Overall, use of topical tranexamic acid or aminocaproic acid reduced postoperative blood loss; however, few studies reported a significant reduction in the number of packed red blood cell transfusions or units given, intensive care unit stay, or length of hospitalization.

CONCLUSIONS:

Topical application of tranexamic acid and aminocaproic acid to decrease postsurgical bleeding after major surgical procedures is a promising strategy. Further data are needed regarding the safety of this hemostatic approach.