Definition of major bleeding in surgery: an anesthesiologist's point of view: a rebuttal

Do Antifibrinolytic Agents Reduce the Risk of Blood Transfusion in Children Undergoing Spinal Fusion?: A Propensity Score-matched Comparison Using a National Database

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

To evaluate the effectiveness and safety of antifibrinolytic (AF) agents in reducing perioperative blood transfusion in pediatric patients undergoing spinal fusion.

SUMMARY OF BACKGROUND DATA

The potential for AF to decrease bleeding and reduce exposure to allogenic transfusions has led to widespread off-label use in a number of major pediatric surgical procedures. Recent reviews call for improving the body of evidence for their effectiveness and safety in pediatric spinal fusion.

METHODS

Children undergoing spinal fusion were identified in the American College of Surgeons National Surgical Quality Improvement Program Pediatric (NSQIP-P) 2016 and 2017 databases. Univariate analyses of patient and perioperative characteristics informed the creation of a propensity score model predicting treatment with AF, followed by 1:1 matching to allow comparison of allogenic red blood cell transfusion rates and secondary outcomes between treated and untreated patients.

RESULTS

Of 6626 total patients, 5434 (81%) received AF and 1533 (23%) received a blood transfusion. Analysis of data for 1192 propensity score-matched pairs revealed that treatment with AF was associated with a statistically nonsignificant 16% reduction in perioperative transfusion (OR 0.84, 95% confidence interval 0.68-1.05, P = 0.119) and a statistically significant 43% reduction in postoperative transfusion (OR 0.57, 95% confidence interval 0.39-0.81, P = 0.002). No differences in the incidences of postoperative seizure or thrombosis were observed, with overall rates of 7.5 and 22.5 events per 10,000 patients, respectively.

CONCLUSION

AF agents appear to reduce postoperative allogenic transfusion in children undergoing spinal fusion surgery. Adverse drug effects such as thromboembolic complications and seizure were extremely rare and warrant continued monitoring, though this is the largest study to date providing evidence for the safety profile of these drugs.

LEVEL OF EVIDENCE

3.

Perioperative cardiovascular complications versus perioperative bleeding in consecutive patients with known cardiac disease undergoing non-cardiac surgery. Focus on antithrombotic medication. The PRAGUE-14 registry

Background

Interruption of antithrombotic treatment before surgery may prevent bleeding, but at the price of increasing cardiovascular complications. This prospective study analysed the impact of antithrombotic therapy interruption on outcomes in non-selected surgical patients with known cardiovascular disease (CVD).

Methods

All 1200 consecutive patients (age 74.2 ± 10.2 years) undergoing major non-cardiac surgery (37.4 % acute, 61.4 % elective) during a period of 2.5 years while having at least one CVD were enrolled. Details on medication, bleeding, cardiovascular complications and cause of death were registered.

Results

In-hospital mortality was 3.9 % (versus 0.9 % mortality among 17,740 patients without CVD). Cardiovascular complications occurred in 91 (7.6 %) patients (with 37.4 % case fatality). Perioperative bleeding occurred in 160 (13.3 %) patients and was fatal in 2 (1.2 % case fatality). Multivariate analysis revealed age, preoperative anaemia, history of chronic heart failure, acute surgery and general anaesthesia predictive of cardiovascular complications. For bleeding complications multivariate analysis found warfarin use in the last 3 days, history of hypertension and general anaesthesia as independent predictive factors. Aspirin interruption before surgery was not predictive for either cardiovascular or for bleeding complications.

Conclusions

Perioperative cardiovascular complications in these high-risk elderly all-comer surgical patients with known cardiovascular disease are relatively rare, but once they occur, the case fatality is high. Perioperative bleeding complications are more frequent, but their case fatality is extremely low. Patterns of interruption of chronic aspirin therapy before major non-cardiac surgery are not predictive for perioperative complications (neither cardiovascular, nor bleeding). Simple baseline clinical factors are better predictors of outcomes than antithrombotic drug interruption patterns.

New direct oral anticoagulants--current therapeutic options and treatment recommendations for bleeding complications

To date, clinical studies show that the incidence of spontaneous bleeding with new direct oral anticoagulants (DOAs) is comparable to that of established anticoagulants. However, unlike vitamin K antagonists, there are currently no clinically available antidotes or approved reversal agents for new DOAs. Restoring normal coagulation is important in many cases, such as emergency surgeries, serious bleedings, or anticoagulant overdosing. Attempts have been made to restore normal coagulation after treatment with new DOAs using compounds such as recombinant activated factor VII (rFVIIa), prothrombin complex concentrate (PCC), or FEIBA (factor eight inhibitor bypassing activity). Limited pre-clinical data and even less clinical evidence are available on the usefulness of these methods in restoring normal coagulation for the emergency management of critical bleeding episodes. Evaluating the utility of DOAs is further complicated by the fact that it is unknown how predictive established test systems are of the bleeding risks. Clinical practice requires further evaluation of the emergency management options for the new DOAs to define the agents and the doses that are most useful. Furthermore, patients receiving long-term treatment with a DOA are likely to undergo elective surgery at some point, and there is lack of evidence regarding perioperative treatment regimens under such conditions. This review summarises potential bleeding management options and available data on the new DOAs.

[Thromboprophylaxis with enoxaparin for total knee replacement: an observational, retrospective and multicentre study comparing starting the treatment before and after the operation]

OBJECTIVE

The low molecular weight heparins are the first option for the prophylaxis of venous thromboembolic disease in major orthopaedic surgery. The time of starting their administration is controversial. The aim of this study was to evaluate the efficacy and safety of enoxaparin in patients subjected to total knee replacement comparing the starting of it before and after the surgery.

METHODS

An observational, retrospective and multicentre study of normal clinical practice to determine the incidence of symptomatic deep venous thrombosis and/or pulmonary thromboembolism in total knee replacement surgery. Thromboprophylaxis was normal practice in each centre. Patients were included if they received the first dose of 40 mg/24 h of enoxaparin either 12 h (± 2 h) before the surgery (G-PRE) or between 6 and 12 hours after the surgery (G-POST). The main safety objective was haemorrhage. A multivariate logistic regression analysis was performed to determine the real influence of each variable.

RESULTS

Data was collected from 2014 patients, of whom 1440 were included for the analysis of efficacy (782/1440, 54% of the G-PRE and 658/1440, 46% of the G-POST). The mean incidence of symptomatic thrombotic events was 1.67% (24/1440). The incidence of deep venous thrombosis in the G-PRE was 1.15% compared to 1.22% in the G-POST (P=.569 after multivariate analysis) and the incidence of pulmonary thromboembolism was 0.51 compared to 0.76%, respectively (P=.582 after multivariate analysis). A total of 1422 patients were included for the safety analysis. There was significant bleeding in 59/788 of the G-PRE and in 35/634 of the G-POST (7.49% compared to 5.52%, respectively, P=.138).

CONCLUSIONS

These results suggest that thromboprophylaxis with enoxaparin (40 mg/24 h sc) in patients subjected to total knee replacement surgery has a similar safety and effective profile when it is given 12 hours before the surgery or between 6 and 12 hours afterwards.

Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

VTE is a common cause of preventable death in surgical patients.

METHODS

We developed recommendations for thromboprophylaxis in nonorthopedic surgical patients by using systematic methods as described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We describe several alternatives for stratifying the risk of VTE in general and abdominal-pelvic surgical patients. When the risk for VTE is very low (< 0.5%), we recommend that no specific pharmacologic (Grade 1B) or mechanical (Grade 2C) prophylaxis be used other than early ambulation. For patients at low risk for VTE (∼1.5%), we suggest mechanical prophylaxis, preferably with intermittent pneumatic compression (IPC), over no prophylaxis (Grade 2C). For patients at moderate risk for VTE (∼3%) who are not at high risk for major bleeding complications, we suggest low-molecular-weight heparin (LMWH) (Grade 2B), low-dose unfractionated heparin (Grade 2B), or mechanical prophylaxis with IPC (Grade 2C) over no prophylaxis. For patients at high risk for VTE (∼6%) who are not at high risk for major bleeding complications, we recommend pharmacologic prophylaxis with LMWH (Grade 1B) or low-dose unfractionated heparin (Grade 1B) over no prophylaxis. In these patients, we suggest adding mechanical prophylaxis with elastic stockings or IPC to pharmacologic prophylaxis (Grade 2C). For patients at high risk for VTE undergoing abdominal or pelvic surgery for cancer, we recommend extended-duration, postoperative, pharmacologic prophylaxis (4 weeks) with LMWH over limited-duration prophylaxis (Grade 1B). For patients at moderate to high risk for VTE who are at high risk for major bleeding complications or those in whom the consequences of bleeding are believed to be particularly severe, we suggest use of mechanical prophylaxis, preferably with IPC, over no prophylaxis until the risk of bleeding diminishes and pharmacologic prophylaxis may be initiated (Grade 2C). For patients in all risk groups, we suggest that an inferior vena cava filter not be used for primary VTE prevention (Grade 2C) and that surveillance with venous compression ultrasonography should not be performed (Grade 2C). We developed similar recommendations for other nonorthopedic surgical populations.

CONCLUSIONS

Optimal thromboprophylaxis in nonorthopedic surgical patients will consider the risks of VTE and bleeding complications as well as the values and preferences of individual patients.

New anticoagulants: pharmacology and clinical studies

The marketing of new anticoagulant drugs has led us to review the development of rivaroxaban and apixaban (oral anti-Xa drugs) and dabigatran (an oral thrombin inhibitor). The results are different in terms of efficacy and tolerance. Each molecule has its own field of application but it is not at all certain that each will find its place. Though the results are favourable for these orally active drugs in the orthopaedic setting, it is clear that only cardiological applications will give a final green light for these products. The future will be fascinating in this regard.

Perioperative deep vein thrombosis prevention: what works, what does not work and does it improve outcome?

PURPOSE OF REVIEW

To critically evaluate the benefit/risk ratio of some strategies for venous thromboembolism prophylaxis (VTE) RECENT FINDINGS: A growing body of evidence shows that graduated elastic stockings are not effective in medical patients. Special surgical settings as bariatric surgery deserve attention with a high VTE risk and no evidence-based data with regard to prophylaxis. Extended prophylaxis is being evaluated in these patients, whereas its efficacy has been demonstrated in abdominal and pelvic surgery for cancer. New oral anticoagulants are about to change the clinical landscape but yet some issues are not solved: no antidote, no monitoring, no standardization for the perioperative bridging in patients with therapeutic doses. In addition, they have not been tested in fragile patients in whom an increased bleeding risk could be feared. Finally, a large bunch of guidelines are now available to help the physician in the decision-making process.

SUMMARY

Studies evaluating the benefit/risk ratio of graduated elastic stockings should now take place in surgery. Increasing and splitting the anticoagulant dose (mainly low molecular weight heparins) by two injections a day could be recommended in bariatric surgery and morbidly obese patients. New anticoagulant agents should also be tested in special populations, following the European Medicines Agency guidance. The methodology of clinical trials in VTE prophylaxis has to be moved forward, pending the choice of debatable surrogate end-points as asymptomatic venous thrombosis and disputed issues on the assessment of major bleeding.