Bivalirudin in pediatric extracorporeal membrane oxygenation

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.

Initial experience with pump controlled retrograde trial-off (PCRTO) veno-arterial extra corporeal membrane oxygenation in children

Pump Controlled Retrograde Trial Off (PCRTO) is a relatively new technique in trialing-off Veno-Arterial Extra Corporeal Membrane Oxygenation (VA-ECMO). Literature on the use of PCRTO in children remains scarce. We describe our centre's initial experience with PCRTO in a neonate and an older child and review its potential advantages and disadvantages compared to traditional weaning methods. More research and shared best practices are required in children to facilitate wider adoption of this technique.

Bivalirudin anticoagulation for an infant with heparin resistance on ECMO: A case report

RATIONALE

Extracorporeal membrane oxygenation (ECMO) technology in the field of intense care for children in China has developed rapidly, and it has become a key strategy for the rescue treatment of critically ill children and an advanced extracorporeal life support system. Compared with adults and children, neonatal respiratory disease with ECMO support has the best prognosis, with an average survival rate of 74%. Bleeding and thrombotic events during ECMO are common, morbid, and potentially lethal. Therefore, how to balance the coagulation state is the key to ECMO management.

PATIENT CONCERNS

A full-term male infant (2h 5min) was hospitalized for respiratory distress and cyanosis. With a history of premature rupture of membranes (>7 hours) and a birth weight of 3000 g, the patient had Apgar scores of 7, 8, and 9 at 1, 5, and 10 minutes, respectively.

DIAGNOSES

This infant has the indication of extracorporeal membrane lung support. After full communication, venoarterial-ECMO was performed, and intravenous infusion of heparin was used for anticoagulation management.

INTERVENTIONS

We encountered an unreliable heparin monitoring in an infant on ECMO, which considered as heparin resistance. Subsequently, we switched the anticoagulant from heparin to bivalirudin and managed by using multiple laboratory tests including activated clotting time (ACT) and activated partial thromboplastin time. The phenomenon of inconsistent monitoring results occurred later. To help the clinic to adjust the anticoagulation dose accurately, we adopted additional tests such as thrombin-antithrombin complex (TAT) and fibrin/fibrinogen degradation products and applied comparison of thrombela stogram (TEG)-ACT with anticoagulated specimens and bedside non-anticoagulated ACT, then recommended clinicians to use activated partial thromboplastin time combined with TAT.

OUTCOMES

In collaboration with other symptomatic supportive treatments, the ECMO flow was gradually reduced, the respiratory and circulatory functions were stable after reducing the flow rate, there was no bleeding tendency, and the ECMO was finally evacuated.

LESSONS

Due to the unique physiological characteristics of newborns, the hemostatic changes differ significantly from those in adults. Precise monitoring of anticoagulation becomes a critical and challenging task. Bivalirudin can be effectively used for anticoagulation management in neonatal ECMO; however, due to its unique characteristics, precise dose adjustment poses a challenge. Selecting the optimal laboratory monitoring indicators is crucial in this regard. In some cases, bedside ACT may not be the optimal anticoagulation monitoring parameter, and when necessary, comparative analysis can be conducted using anticoagulant-sample ACTs such as thrombela stogram-ACT. Traditional markers such as D-dimer/fibrinogen degradation products and newer indicators like TAT can reflect the activation of coagulation and assist in monitoring the anticoagulation effect, especially when there is conflicting information among the monitoring parameters.

Bivalirudin Monitoring in Pediatric Ventricular Assist Device and Extracorporeal Membrane Oxygenation: Analysis of Single-Center Retrospective Cohort Data 2018-2022

OBJECTIVES

The activated partial thromboplastin time (aPTT) is the most frequently used monitoring assay for bivalirudin in children and young adults on mechanical circulatory support including ventricular assist devices (VADs) and extracorporeal membrane oxygenation (ECMO). However, intrinsic variability of the aPTT complicates management and risks bleeding or thrombotic complications. We evaluated the utility and reliability of a bivalirudin-calibrated dilute thrombin time (Bival dTT) assay for bivalirudin monitoring in this population.

DESIGN

Retrospective analysis of clinical data (including aPTT, dilute thrombin time [dTT]) and results of residual plasma samples from VAD patients were assessed in two drug-calibrated experimental assays. One assay (Bival dTT) was validated for clinical use in VAD patients, and subsequently used by clinicians in ECMO patients. Pearson correlation and simple linear regression were used to determine R2 correlation coefficients between the different laboratory parameters using Statistical Package for Social Sciences (Armonk, NY).

SETTING

ICUs at Cincinnati Children's Hospital Medical Center.

SUBJECTS

Children on VAD or ECMO support anticoagulated with bivalirudin.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred fifteen plasma samples from 11 VAD patients were analyzed. Both drug-calibrated experimental assays (anti-IIa and Bival dTT) showed excellent correlation with each other ( R2 = 0.94) and with the dTT ( R2 = 0.87), but poor correlation with aPTT ( R2 = 0.1). Bival dTT was selected for validation in VAD patients. Subsequently, clinically ordered results (105) from 11 ECMO patients demonstrated excellent correlation between the Bival dTT and the standard dTT ( R2 = 0.86) but very poor correlation with aPTT ( R2 = 0.004).

CONCLUSIONS

APTT is unreliable and correlates poorly with bivalirudin's anticoagulant effect in ECMO and VAD patients. A drug-calibrated Bival dTT offers superior reliability and opportunity to standardize results across institutions. Additional studies are needed to determine an appropriate therapeutic range and correlation with clinical outcomes.

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.

Anticoagulation with argatroban using hemoclot™ targets is safe and effective in CARDS patients receiving venovenous extracorporeal membrane oxygenation: An exploratory bi-centric cohort study

Direct thrombin inhibitors, including argatroban, are increasingly used for anticoagulation during venovenous extracorporeal membrane oxygenation (VV ECMO). In many centers activated partial thromboplastin time (aPTT) is used for monitoring, but it can be affected by several confounders. The aim of this study was to evaluate the safety and efficacy of anticoagulation with argatroban titrated according to diluted thrombin time targets (hemoclot™ assay) compared to anti-Xa guided anticoagulation with unfractionated heparin (UFH).

METHODS

This cohort study included adults at two tertiary care centers who required VV ECMO for severe COVID-19-related acute respiratory distress syndrome (CARDS). Patients received center-dependent argatroban or UFH for anticoagulation during ECMO. Argatroban was guided following a hemoclot™ target range of 0.4-0.6 μg/ml. UFH was guided by anti-factor Xa (antiXa) levels (0.2-0.3 IU/ml). The primary outcome was safety of argatroban compared to UFH, assessed by time to first clinically relevant bleeding event or death during ECMO. Secondary outcomes included efficacy (time to thromboembolism) and feasibility (proportion of anticoagulation targets within range).

RESULTS

From 2019 to 2021 57 patients were included in the study with 27 patients (47 %) receiving argatroban and 30 patients (53 %) receiving UFH. The time to the first clinically relevant bleeding or death during ECMO was similar between groups (HR (argatroban vs. UFH): 1.012, 95 % CI 0.44-2.35, p = 0.978). Argatroban was associated with a decreased risk for thromboembolism compared to UFH (HR 0.494 (95 % CI 0.26-0.95; p = 0.034)). The overall proportion of anticoagulation within target ranges was not different between groups (46 % (23-54 %) vs. 46 % (37 %-57 %), p = 0.45).

CONCLUSION

Anticoagulation with argatroban according to hemoclot™ targets (0.4-0.6 μg/ml) compared to antiXa guided UFH (0.2-0.3 IU/ml) is safe and may prolong thromboembolism-free time in patients with severe ARDS requiring VV ECMO.