Prospective Exploratory Experience With Bivalirudin Anticoagulation in Pediatric Extracorporeal Membrane Oxygenation

Anticoagulation during extracorporeal membrane oxygenation: A narrative review

Extracorporeal Membrane Oxygenation (ECMO) is a technology that offers organ support for critically ill patients with respiratory and/or cardiac failure. Despite improvements in recent years in technology and the biocompatibility of circuits, patients on ECMO remain at high risk of hematologic complications, such as bleeding or thrombosis. Anticoagulation is required in most cases to limit the risk of clotting, but questions persist regarding the optimal anticoagulation strategy. More precisely, there is still debate around the best anticoagulation agent and monitoring tools as well as on the transfusion thresholds and appropriate corrective measures when faced with complications. This narrative review provides an overview of hemostasis on ECMO and the impact of circuit size and coating. The benefits and downsides of unfractionated heparin (UHF) and Direct Thrombin Inhibitors (DTIs) as anticoagulation agents are reviewed. Finally, commonly available coagulation tests (activated clotting time, activated partial thrombin time, anti-Xa, and viscoelastic tests) and their limitations are addressed. In conclusion, future research is needed to determine the best anticoagulation strategy for patients on ECMO.

Bleeding Complications between Bivalirudin and Heparin for Extracorporeal Membrane Oxygenation in Neonates with Congenital Diaphragmatic Hernia

INTRODUCTION

Neonates with congenital diaphragmatic hernia (CDH) who undergo repair while on extracorporeal membrane oxygenation (ECMO) are at risk of developing post-operative bleeding complications. Balanced anticoagulation is critical to maintain ECMO flow and avoid bleeding. Heparin has historically been our first-line anticoagulant; however, recently, we transitioned to bivalirudin, a direct thrombin inhibitor. The objective of this pilot study was to compare post-operative surgical bleeding complications between the two groups.

METHODS

We performed a single center retrospective cohort study of patients who underwent CDH repair while on ECMO between 2008 and 2023. Neonates were stratified based on the type of anticoagulant initiated after CDH repair. Outcomes included bleeding requiring surgical re-operation, intracranial hemorrhage, volume of blood products transfused, number of circuit changes, days on ECMO, and overall survival.

RESULTS

Among 62 neonates with CDH who underwent repair on ECMO, 44 (71%) were managed post-CDH repair with heparin and 18 (29%) with bivalirudin. One (5.6%) neonate managed with bivalirudin underwent re-operation following CDH repair for a bleeding complication compared to 17 (38.6%) managed with heparin (p = 0.022). In addition, the bivalirudin cohort utilized half of the total blood product volume compared to the heparin cohort (p = 0.020). Despite these benefits, there were no significant differences between groups for incidence of intracranial hemorrhage, number of circuit changes, days on ECMO, and overall survival.

CONCLUSION

Anticoagulation with bivalirudin in neonates who underwent CDH repair while on ECMO was associated with decreased surgical bleeding complications and less total blood product transfused. This pilot analysis is the first to compare heparin to bivalirudin and stresses the importance of a multicenter study.

Bivalirudin as an anticoagulation strategy for acute hemodialysis in children: Two cases with a summary of recent literature

Unfractionated heparin is the most used anticoagulative agent for extracorporeal settings in children, including acute hemodialysis modalities. In certain situations, such as heparin-induced thrombocytopenia, alternatives must be applied. The direct thrombin inhibitor bivalirudin has come forth as an attractive substitute. Bivalirudin is currently only approved for adult use in specific percutaneous coronary intervention settings. However, it has a growing off-label popularity in different contexts for both adult and pediatric patients. Experience with bivalirudin in children is mainly limited to extracorporeal membrane oxygenation, ventricular assist devices and during cardiopulmonary bypass surgery. Literature about its use as anticoagulation strategy for pediatric hemodialysis is very scarce. Here, we present two pediatric cases where bivalirudin was used during acute hemodialysis, followed by a short summary of recent literature.

Anticoagulant Medications: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To derive systematic-review informed, modified Delphi consensus regarding the medications used for anticoagulation for pediatric extracorporeal membrane oxygenation (ECMO) for the Pediatric ECMO Anticoagulation CollaborativE (PEACE).

DATA SOURCES

A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021.

STUDY SELECTION

Included studies assessed anticoagulation used in pediatric ECMO.

DATA EXTRACTION

Two authors reviewed all citations independently, with a third reviewer adjudicating any conflicts. Eighteen references were used for data extraction as well as for creation of recommendations. Evidence tables were constructed using a standardized data extraction form.

DATA SYNTHESIS

Risk of bias was assessed using the Quality in Prognosis Studies tool. The evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation system. Forty-eight experts met over 2 years to develop evidence-informed recommendations and, when evidence was lacking, expert-based consensus statements, or good practice statements for anticoagulation during pediatric ECMO. A web-based modified Delphi process was used to build consensus via the Research and Development/University of California Appropriateness Method. Consensus was based on a modified Delphi process with agreement defined as greater than 80%. Two recommendations, two consensus statements, and one good practice statement were developed, and, in all, agreement greater than 80% was reached.

CONCLUSIONS

There is insufficient evidence to formulate optimal anticoagulation therapy during pediatric ECMO. Additional high-quality research is needed to inform evidence-based practice for anticoagulation during pediatric ECMO.

Priorities for Clinical Research in Pediatric Extracorporeal Membrane Oxygenation Anticoagulation From the Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To identify and prioritize research questions for anticoagulation and hemostasis management of neonates and children supported with extracorporeal membrane oxygenation (ECMO) from the Pediatric ECMO Anticoagulation CollaborativE (PEACE) consensus.

DATA SOURCES

Systematic review was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021, followed by serial consensus conferences of international, interprofessional experts in the management of ECMO for critically ill neonates and children.

STUDY SELECTION

The management of ECMO anticoagulation for critically ill neonates and children.

DATA EXTRACTION

Within each of the eight subgroups, two authors reviewed all citations independently, with a third independent reviewer resolving any conflicts.

DATA SYNTHESIS

Following the systematic review of MEDLINE, EMBASE, and Cochrane Library databases from January 1988 to May 2021, and the consensus process for clinical recommendations and consensus statements, PEACE panel experts constructed research priorities using the Child Health and Nutrition Research Initiative methodology. Twenty research topics were prioritized, falling within five domains (definitions and outcomes, therapeutics, anticoagulant monitoring, protocolized management, and impact of the ECMO circuit and its components on hemostasis).

CONCLUSIONS

We present the research priorities identified by the PEACE expert panel after a systematic review of existing evidence informing clinical care of neonates and children managed with ECMO. More research is required within the five identified domains to ultimately inform and improve the care of this vulnerable population.

Anticoagulation Monitoring and Targets: The Pediatric Extracorporeal Membrane Oxygenation Anticoagulation CollaborativE Consensus Conference

OBJECTIVES

To derive systematic-review informed, modified Delphi consensus regarding anticoagulation monitoring assays and target levels in pediatric extracorporeal membrane oxygenation (ECMO) for the Pediatric ECMO Anticoagulation CollaborativE.

DATA SOURCES

A structured literature search was performed using PubMed, EMBASE, and Cochrane Library (CENTRAL) databases from January 1988 to May 2021.

STUDY SELECTION

Anticoagulation monitoring of pediatric patients on ECMO.

DATA EXTRACTION

Two authors reviewed all citations independently, with a third independent reviewer resolving any conflicts. Evidence tables were constructed using a standardized data extraction form.

DATA SYNTHESIS

Risk of bias was assessed using the Quality in Prognosis Studies tool or the revised Cochrane risk of bias for randomized trials, as appropriate and the evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation system. Forty-eight experts met over 2 years to develop evidence-based recommendations and, when evidence was lacking, expert-based consensus statements for clinical recommendations focused on anticoagulation monitoring and targets, using a web-based modified Delphi process to build consensus (defined as > 80% agreement). One weak recommendation, two consensus statements, and three good practice statements were developed and, in all, agreement greater than 80% was reached. We also derived some resources for anticoagulation monitoring for ECMO clinician use at the bedside.

CONCLUSIONS

There is insufficient evidence to formulate optimal anticoagulation monitoring during pediatric ECMO, but we propose one recommendation, two consensus and three good practice statements. Overall, the available pediatric evidence is poor and significant gaps exist in the literature.

Diaphragmatic Defects in Infants: Acute Management and Repair

Congenital diaphragmatic hernia (CDH) is a complex and highly variable disease process that should be treated at institutions with multidisciplinary teams designed for their care. Treatment in the neonatal period focuses on pulmonary hypoplasia, pulmonary hypertension, and cardiac dysfunction. Extracorporeal membrane oxygenation (ECMO) can be considered in patients refractory to medical management. Repair of CDH early during the ECMO course seems to improve mortality compared with other times for surgical intervention. The choice of surgical approach to CDH repair should consider the patient's physiologic status and the surgeon's familiarity with the operative approaches available, recognizing the pros/cons of each technique.

Impact of inflammation and steroids on anti-coagulation in children supported on a ventricular assist device

Critically ill pediatric patients supported on ventricular assist devices (VADs) are increasingly being anticoagulated on bivalirudin, but with difficulty monitoring anticoagulation. Activated partial thromboplastin time (aPTT) has recently been shown to poorly correlate with bivalirudin plasma concentrations, while dTT had excellent correlation. However, aPTT is the more common monitoring test and dTT testing is rarely used. In addition, effects of frequent clinical VAD scenarios (such as inflammation) on the accuracy of aPTT and dTT testing remains uncertain. We reviewed the effects of clinical scenarios (infection/inflammation, chylothorax, and steroids administration) on anticoagulation monitoring in 10 pediatric VAD patients less than 3 years at Cincinnati Children's Hospital Medical Center from 10/27/2020 to 5/6/2022 using bivalirudin for anticoagulation. There were 16 inflammation/infection, 3 chylothorax, and 6 steroids events. Correlation between dTT and aPTT was significantly lower after infection/inflammation, with dTT increasing prior to inflammation/infection while aPTT remained unchanged. In addition, steroids are administered to VAD patients to reduce inflammation and thus additionally stabilize anticoagulation. However, this anticoagulation stabilization effect was reflected more accurately by dTT compared to aPTT. In children requiring VAD support utilizing bivalirudin anticoagulation, inflammation/infection is a common occurrence resulting in anticoagulation changes that may be more accurately reflected by dTT as opposed to aPTT.

Epidemiology of anticoagulation for children supported by extracorporeal membrane oxygenation in the United States: A Pediatric Hospital Information System database study

INTRODUCTION

Due to the risk of thrombosis, nearly all children supported by extracorporeal membrane oxygenation (ECMO) receive systemic anticoagulation. While heparin has traditionally been used, there are reports of increased use of direct thrombin inhibitors. We sought to describe the use of anticoagulation in children supported by ECMO in the United States using a large administrative database.

METHODS

We performed a retrospective cohort study of children supported by ECMO within the Pediatric Health Information System (PHIS) database. Pediatric encounters involving ECMO from 2012 to 2020 were identified. Data regarding demographics, diagnoses, anticoagulation, complications, and outcomes were extracted for eligible encounters.

RESULTS

Eleven thousand five hundred ninety-five encounters that involved ECMO were identified. Fifty-four percent were male with an age range of 0-17 years and a median (IQR) age of 0 (0-2) years. Unfractionated heparin (UFH) only was used in 94% (95% CI: 93.6-94.5%) of encounters and UFH followed by bivalirudin in 5% (95% CI: 4.3-5.1%) of cases. There was a significant difference in the use of bivalirudin from 2012 to 2020 (p < 0.001). Differences in anticoagulation regimens were observed between infants and children (p = 0.004) and between those with and without cardiac indications for ECMO (p < 0.001). Four percent (95% CI: 4.1-4.8%) of encounters were associated with diagnostic coding for thrombosis and differences in occurrence of thrombosis were observed between different anticoagulant regimens (p < 0.001).

CONCLUSIONS

Though the majority of children on ECMO in the United States receive heparin anticoagulation, there is an increase in use of direct thrombin inhibitors. Prospective studies must evaluate the efficacy of different anticoagulants in this patient population.

Anticoagulation with Intravenous Direct Thrombin Inhibitors in Pediatric Extracorporeal Membrane Oxygenation: A Systematic Review of the Literature

Although intravenous (IV) direct thrombin inhibitors (DTI) have gained interest in pediatric extracorporeal membrane oxygenation (ECMO), dosing and safety information is limited. The objective of this systematic review was to characterize DTI types, dosing, monitoring, and outcomes (bleeding and thromboembolic) in pediatric ECMO patients managed with IV DTIs. We conducted searches of MEDLINE (Ovid) and Embase (Elsevier) from inception through December 2022. Case reports, retrospective studies, and prospective studies providing per-patients or summary data for patient(s) <18 years of age receiving IV DTI for ECMO anticoagulation were included. Study selection and data extraction were conducted independently by two reviewers. A total of 28 studies: 14 case reports, 13 retrospective studies, and 1 prospective study were included, totaling 329 patients. Bivalirudin was utilized in 318 (96.7%), argatroban in 9 (2.7%), and lepirudin in 2 (0.6%) patients. Infusion dosing included: bivalirudin 0.14 ± 0.37 mg/kg/h, argatroban 0.69 ± 0.73 µg/kg/min, lepirudin 0.14 ± 0.02 mg/kg/h. Laboratory monitoring tests utilized were the activated clotting time, activated partial thromboplastin time (aPTT), diluted thrombin time, and thromboelastography measures. The aPTT was utilized in most patients (95%). Thromboembolism, bleeding, or death were observed in 17%, 17%, and 23% of bivalirudin, argatroban, and lepirudin patients, respectively. Bivalirudin appears to be the most frequently used DTI in pediatric ECMO. Dosing and laboratory monitoring varied, and bleeding and thromboembolic events were reported in 17% of patients. Prospective studies are warranted to establish dosing, monitoring, safety, and efficacy of bivalirudin and other IV DTI in pediatric ECMO.

Bivalirudin or heparin for systemic anticoagulation during pediatric extracorporeal membrane oxygenation: Multicenter retrospective study

BACKGROUND

The objective of this study is to evaluate the outcomes of unfractionated heparin (UFH) compared to bivalirudin anticoagulation in pediatric ExtraCorporeal Membrane Oxygenation (ECMO).

METHODS

A multicenter retrospective study, that included pediatric patients <18 years of age, who were supported on ECMO between June 2017 and May 2020. Patients treated with UFH were matched 2:1 by age and type of ECMO support to the bivalirudin group.

RESULTS

The bivalirudin group (75 patients) were matched to 150 patients treated with UFH. Baseline characteristics and comorbidities of the two groups were similar. Veno-Arterial ECMO was the most common mode (141/225 [63 %]) followed by extracorporeal cardiopulmonary resuscitation (48/225 [21 %]). Bivalirudin treatment was associated with lower odds of bleeding events (aOR 0.23, 95%CI 0.12-0.45, p < 0.001) and lower odds of thrombotic events (aOR 0.48, 95%CI 0.23-0.98, p = 0.045). Patients who received bivalirudin had lesser odds for transfusion with fresh frozen plasma, and platelets (aOR 0.26, CI 0.12-0.57, p ≤0.001 and aOR 0.28, CI 0.15-0.53, p < 0.001, respectively). After adjusting for the type of ECMO support and adjusting for age, bivalirudin was associated with a decrease in hospital mortality by 50 % compared to the UFH group (aOR 0.50, 95%CI 0.27-0.93, p = 0.028). Similarly, for neurological disability at time of discharge, bivalirudin was associated with higher odds of intact neurological outcomes compared to UFH (OR 1.99 [95%CI 1.13-3.51], p = 0.017).

CONCLUSIONS

This study demonstrated that effective anticoagulation can be achieved with bivalirudin, which was associated with lesser odds of bleeding events and utilization of blood products. Bivalirudin, in comparison with UFH, was associated with greater odds of hospital survival and intact neurological function at the time of discharge. A prospective randomized trial is required to validate the results of this study.

Bivalirudin Compared to Heparin as the Primary Anticoagulant in Pediatric Berlin Heart Recipients

Bivalirudin has been used in increasing frequency as an alternative to unfractionated heparin (UFH) in pediatric recipients of Berlin Heart EXCOR ventricular assist devices (VAD). This single-center, retrospective review characterizes anticoagulant trends and outcomes in pediatric Berlin Heart VAD recipients implanted between September 1, 2013, and August 31, 2021, anticoagulated with either bivalirudin or UFH. Thirty-one patients were included; 65% who received bivalirudin and 35% who received UFH. The median age was 2.9 years, included 64.5% females, with 61.3% of patients diagnosed with dilated cardiomyopathy and 25.8% of patients with congenital heart disease. Therapeutic anticoagulation was achieved sooner in the bivalirudin group compared to UFH via anti-Xa monitoring (median 5.7 and 69.5 hours, respectively, p < 0.001). Bivalirudin had a greater number of therapeutic values comparatively to UFH (52% and 24%, respectively; p < 0.001) and a superior number of hours in the therapeutic range (67% and 32%, respectively; p < 0.001). Secondary outcomes were similar among the two groups, apart from greater chest tube output (UFH), more frequent events of elevated plasma-free hemoglobin (bivalirudin), and more frequent elevated inflammatory markers postimplant (bivalirudin). Prevalence of pump replacements secondary to significant clot burden and prevalence of stroke was comparable. In this patient cohort, bivalirudin demonstrated greater anticoagulation stability comparatively to UFH. Multicenter collaboration would be necessary to identify whether this further translates into improved patient outcomes.

Heparin-based versus bivalirudin-based anticoagulation in pediatric extracorporeal membrane oxygenation: A systematic review

Introduction

Optimal anticoagulation therapy is essential for the prevention of thrombotic and hemorrhagic complications in pediatric patients supported with extracorporeal membrane oxygenation (ECMO). Recent data have demonstrated bivalirudin has the potential to surpass and replace heparin as the anticoagulant of choice.

Methods

We conducted a systematic review comparing the outcomes of heparin-based versus bivalirudin-based anticoagulation in pediatric patients supported on ECMO to identify the preferred anticoagulant to minimize bleeding events, thrombotic complications, and associated mortality. We referenced the PubMed, Cochrane Library, and Embase databases. These databases were searched from inception through October 2022. Our initial search identified 422 studies. All records were screened by two independent reviewers using the Covidence software for adherence to our inclusion criteria, and seven retrospective cohort studies were identified as appropriate for inclusion.

Results

In total, 196 pediatric patients were anticoagulated with heparin and 117 were anticoagulated with bivalirudin while on ECMO. Across the included studies, it was found that for patients treated with bivalirudin, trends were noted toward lower rates of bleeding, transfusion requirements, and thrombosis with no difference in mortality. Overall costs associated with bivalirudin therapy were lower. Time to therapeutic anticoagulation varied between studies though institutions had different anticoagulation targets.

Conclusion

Bivalirudin may be a safe, cost-effective alternative to heparin in achieving anticoagulation in pediatric ECMO patients. Prospective multicenter studies and randomized control trials with standard anticoagulation targets are needed to accurately compare outcomes associated with heparin versus bivalirudin in pediatric ECMO patients.

Evaluation of clinical outcomes in patients treated with heparin or direct thrombin inhibitors during extracorporeal membrane oxygenation: a systematic review and meta-analysis

BACKGROUND

The number of patients treated with extracorporeal membrane oxygenation (ECMO) devices is increasing. Anticoagulation therapy is crucial to prevent thrombosis during ECMO therapy. Predominantly, heparin has been used as primary anticoagulant but direct thrombin inhibitors (DTI) have been established as alternatives. The aim of this systematic review and meta-analysis was to evaluate clinical outcomes in patients treated with heparin compared to different DTI during ECMO.

METHODS

A systematic search was conducted. Full scientific articles were sought for inclusion if heparin anticoagulation was compared to DTI (argatroban/bivalirudin) in ECMO patients. Risk of bias was assessed by Newcastle Ottawa scale. Primary endpoint was in-hospital mortality. Bleeding events, thrombotic events, hours of ECMO support, days of hospital stay, percentage of time within therapeutic range and time to therapeutic range were extracted from full texts as secondary endpoints. Results were presented as Forrest-plots. GRADE was used for confidence assessment in outcomes.

RESULTS

Systematic search identified 4.385 records, thereof 18 retrospective studies for a total of 1942 patients, complied with the predefined eligibility criteria:15 studies investigated bivalirudin and 3 studies investigated argatroban versus heparin. Risk of bias was high for most studies. In-hospital mortality, major bleeding events and pump-related thrombosis were less frequent in DTI group as compared to heparin [mortality-OR 0.69, 95% CI 0.54-0.86; major bleeding-OR 0.48, 95% CI 0.29-0.81; pump thrombosis-OR 0.55, 95% CI 0.40-0.76]. Additionally, percentage of time within therapeutic range was higher for DTI [SMD 0.54, 95% CI 0.14-0.94]. GRADE approach revealed a very low level of certainty for each outcome.

CONCLUSION

In this meta-analysis, DTI and especially bivalirudin showed beneficial effects on clinical outcomes in ECMO patients as compared to heparin. However, due to the lack of randomized trials, certainty of evidence is low.

TRIAL REGISTRATION

This systematic review and meta-analysis was prospectively registered at PROSPERO data base (reference number CRD42021237252 ).

The Changing Landscape of Anticoagulation in Pediatric Extracorporeal Membrane Oxygenation: Use of the Direct Thrombin Inhibitors

Bleeding and thrombosis frequently occur in pediatric patients with extracorporeal membrane oxygenation (ECMO) therapy. Until now, most patients are anticoagulated with unfractionated heparin (UFH). However, heparin has many disadvantages, such as binding to other plasma proteins and endothelial cells in addition to antithrombin, causing an unpredictable response, challenging monitoring, development of heparin resistance, and risk of heparin-induced thrombocytopenia (HIT). Direct thrombin inhibitors (DTIs), such as bivalirudin and argatroban, might be a good alternative. This review will discuss the use of both UFH and DTIs in pediatric patients with ECMO therapy.

Bivalirudin in pediatric extracorporeal membrane oxygenation

PURPOSE OF REVIEW

This review summarizes the current literature surrounding the use of bivalirudin as an alternative anticoagulant for pediatric extracorporeal membrane oxygenation (ECMO) patients.

RECENT FINDINGS

Recent single center studies describe that bivalirudin may be associated with decreased blood product transfusion, decreased cost and similar clinical outcomes for pediatric ECMO patients who have failed unfractionated heparin (UFH) anticoagulation. aPTT is the most common test to monitor bivalirudin but has several limitations. Other tests including dilute thrombin time (dTT) and viscoelastic assays are promising but more study is needed. Current evidence suggests that bivalirudin is a well tolerated and effective alternative anticoagulant for pediatric ECMO patients who have failed UFH anticoagulation but prospective studies are needed to confirm these results.

SUMMARY

Bivalirudin is a promising alternative anticoagulant for pediatric ECMO patients who have failed UFH. Large prospective, multicenter studies are needed to confirm safety and efficacy.

The Efficacy and Safety of Bivalirudin Versus Heparin in the Anticoagulation Therapy of Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis

Background: Bivalirudin is a direct thrombin inhibitor (DTI) that can be an alternative to unfractionated heparin (UFH). The efficacy and safety of bivalirudin in anticoagulation therapy in extracorporeal membrane oxygenation (ECMO) remain unknown. Methods: This study followed the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A systematic literature search was performed in PubMed, EMBASE, and The Cochrane Library databases to identify all relevant original studies estimating bivalirudin's efficacy and safety versus UFH as anticoagulation therapy in ECMO. The time limit for searching is from the search beginning to June 2021. Two researchers independently screened the literature, extracted data and evaluated the risk of bias of the included studies. The meta-analysis (CRD42020214713) was performed via the RevMan version 5.3.5 Software and STATA version 15.1 Software. Results: Ten articles with 847 patients were included for the quantitative analysis. Bivalirudin can significantly reduce the incidence of major bleeding in children (I 2 = 48%, p = 0.01, odd ratio (OR) = 0.17, 95% confidence interval (CI): 0.04-0.66), patient thrombosis (I 2 = 0%, p = 0.02, OR = 0.58, 95% CI: 0.37-0.93), in-circuit thrombosis/interventions (I 2 = 0%, p = 0.0005, OR = 0.40, 95% CI: 0.24-0.68), and in-hospital mortality (I 2 = 0%, p = 0.007, OR = 0.64, 95% CI: 0.46-0.88). Also, comparable clinical outcomes were observed in the incidence of major bleeding in adults (I 2 = 48%, p = 0.65, OR = 0.87, 95% CI: 0.46-1.62), 30-day mortality (I 2 = 0%, p = 0.61, OR = 0.83, 95% CI: 0.41-1.68), and ECMO duration in adults (I 2 = 41%, p = 0.75, mean difference (MD) = -3.19, 95% CI: -23.01-16.63) and children (I 2 = 76%, p = 0.65, MD = 40.33, 95% CI:-135.45-216.12). Conclusions: Compared with UFH, bivalirudin can be a safe and feasible alternative anticoagulant option to UFH as anticoagulation therapy in ECMO, especially for heparin resistance (HR) and heparin-induced thrombocytopenia (HIT) cases.

Bivalirudin versus Heparin in Pediatric and Adult Patients on Extracorporeal Membrane Oxygenation: A Meta-analysis

AIMS

Unfractionated heparin (UFH) has been the primary anticoagulant of choice on extracorporeal membrane oxygenation (ECMO). However, it is debatable whether bivalirudin (BIV), a direct thrombin inhibitor, may be considered a better alternative anticoagulant option.

METHODS

We searched Embase, Pubmed, Cochrane library, Clinicaltrials.gov, CNKI, and Wanfang databases up to June 15, 2021. Randomized controlled trials (RCTs) and observational studies were considered eligible for inclusion. Random-effects meta-analyses, including subgroup analyses, were conducted.

RESULTS

A total of 9 studies containing 994 patients were enrolled. All articles were retrospective cohort studies. Compared with UFH, BIV was associated with lower risks of major bleeding (risk ratio [RR]: 0.32, 95% confidence interval [CI] 0.22-0.49), ECMO in-circuit thrombosis (RR: 0.57, 95% CI 0.43-0.74), stroke (RR: 0.52, 95% CI 0.29-0.95), in-hospital mortality (RR: 0.82, 95% CI 0.69-0.99) and higher rates of survival to ECMO decannulation (RR: 1.18, 95% CI 1.03-1.34). Pooled risk estimates did not show a significant association with clinical thrombotic events (RR: 0.69, 95% CI 0.45-1.07). Moreover, BIV was associated with a lower risk of ECMO in-circuit thrombosis and in-hospital mortality in the adult subgroup but not in the pediatric subgroup. However, leave-one-out sensitivity analyses indicated that the results of stroke, survival to ECMO decannulation and in-hospital mortality should be interpreted with caution.

CONCLUSIONS

BIV appears to be a potential alternative to UFH in pediatric and adult patients requiring ECMO.

Extracorporeal membrane oxygenation in critically ill neonatal and pediatric patients with acute respiratory failure: a guide for the clinician

Intro: Extracorporeal membrane oxygenation for neonatal and pediatric respiratory failure continues to demonstrate improving outcomes, largely due to advances in technology along with refined management strategies despite mounting patient acuity and complexity. Successful use of ECMO requires thoughtful initiation and candidacy strategies, along with reducing the risk of ventilator induced lung injury and the progression to multiorgan failure.Areas Covered: This review describes current ECMO management strategies for neonatal and pediatric patients with acute refractory respiratory failure and summarizes relevant published literature. ECMO initiation and candidacy, along with ventilator and sedation management, are highlighted. Additionally, rapidly expanding areas of interest such as anticoagulation strategies, transfusion thresholds, rehabilitation on ECMO, and drug pharmacokinetics are described.Expert Opinion: Over the last few decades, published studies supporting ECMO use for acute refractory respiratory failure, along with institutional experience, have resulted in increased utilization although more randomized-controlled trials are needed. Future research should focus on filling the knowledge gaps that remain regarding anticoagulation, transfusion thresholds, ventilator strategies, sedation, and approaches to rehabilitation to subsequently implement into clinical practice. Additionally, efforts should focus on well-designed trials, including population pharmacokinetic studies, to develop dosing recommendations.

Venous Thromboembolism among Critically Ill Children: A Narrative Review

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality among hospitalized patients, including children. In recent years, it has become clear that hospitalization and critical illness bestow an increased VTE risk in pediatrics and relate to mortality and life-limiting comorbidities. For critically ill children, reported rates of VTE vary by study sampling techniques, presence of inherited or acquired thrombophilia, acute and chronic immobility, underlying illness prompting hospitalization, and clinical factors related to illness severity such as central venous catheterization, length of stay, mechanical ventilation, and patient age. Accordingly, critically ill children with new signs of venous congestion, acute inflammation, or unexplained acute organ dysfunction should be routinely evaluated for VTE. This narrative review summarizes recent and historical literature regarding risk factors, prevention, presentation, treatment, and outcomes of VTE in critically ill children. In addition, we identify knowledge gaps and priorities for future collaborative research on this vital condition. Special attention is given to the clinical trial opportunities, challenges, and ongoing efforts in thromboprophylaxis in critically ill children, including those hospitalized for disease related to novel coronavirus (COVID-19) and multisystem inflammatory disease in children.

Comparison of Bivalirudin Versus Heparin for Maintenance Systemic Anticoagulation During Adult and Pediatric Extracorporeal Membrane Oxygenation

OBJECTIVES

To provide a comparative analysis of conventional heparin-versus bivalirudin-based systemic anticoagulation in adult and pediatric patients supported on extracorporeal membrane oxygenation.

DESIGN

Retrospective chart review study of adult and pediatric patients receiving extracorporeal membrane oxygenation from January 1, 2014, to October 1, 2019.

SETTING

A large, high-volume tertiary referral adult and pediatric extracorporeal membrane oxygenation center.

PATIENTS

Four hundred twenty-four individuals requiring extracorporeal membrane oxygenation support and systemically anticoagulated with either unfractionated heparin (223 adult and 65 pediatric patients) or bivalirudin (110 adult and 24 pediatric patients) were included.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Digital data abstraction was used to retrospectively collect patient details. The majority of both groups were cannulated centrally (67%), and the extracorporeal membrane oxygenation type was predominantly venoarterial (84%). The adult bivalirudin group had a greater occurrence of heparin-induced thrombocytopenia (12% vs 1%; p < 0.01) and was more likely to require postcardiotomy extracorporeal membrane oxygenation (36% vs 55%; p < 0.01). There were no statistical differences between the groups in regards to age, sex, and extracorporeal membrane oxygenation initiation location. The main finding was a reduced mortality in the adult bivalirudin group (odds ratio, 0.39; p < 0.01), whereas no difference was noted in the pediatric group. A significant reduction in the composite transfusion requirement in the first 24 hours was noted in the pediatric bivaluridin group with an odds ratio of 0.28 (p = 0.02). Groups did not differ in regard to laboratories per day, anticoagulant dose adjustments, or ischemic complications.

CONCLUSIONS

When compared with heparin-based systemic anticoagulation, bivalirudin demonstrated feasibility and safety as established by the absence of increases in identifiable adverse outcomes while manifesting substantial improvements in hospital mortality in adult patients. Further studies are necessary to corroborate these findings and further elucidate the role of bivalirudin during extracorporeal membrane oxygenation support.

Continuous renal replacement therapy in patients treated with extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a life‐saving therapy utilized for patients with severe life‐threatening cardiorespiratory failure. Patients treated with ECMO are among the most severely ill encountered in critical care and are at high‐risk of developing multiple organ dysfunction, including acute kidney injury (AKI) and fluid overload. Continuous renal replacement therapy (CRRT) is increasingly utilized inpatients on ECMO to manage AKI and treat fluid overload. The indications for renal replacement therapy for patients on ECMO are similar to those of other critically ill populations; however, there is wide practice variation in how renal supportive therapies are utilized during ECMO. For patients requiring both CRRT and ECMO, CRRT may be connected directly to the ECMO circuit, or CRRT and ECMO may be performed independently. This review will summarize current knowledge of the epidemiology of AKI, indications and timing of CRRT, delivery of CRRT, and the outcomes of patients requiring CRRT with ECMO.