aPTT-guided anticoagulation monitoring during ECMO support: A systematic review and meta-analysis

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.

Anticoagulation in venovenous extracorporeal membrane oxygenation

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is a lifesaving therapy in severe acute respiratory distress syndrome (ARDS). Unfortunately, bleeding and thrombotic complications occur regularly due to coagulation disorders associated with the device, the underlying disease, and the anticoagulation management. To facilitate a personalized approach to hemostasis in individuals receiving ECMO support, it is essential to assess the coagulative state of the patient while simultaneously taking into account the underlying medical condition and administered therapies.

Anticoagulation Monitoring During ECMO Support: Monitor or Flip a Coin?

Should we rely on anticoagulation monitoring in ECMO patients or simply flip a coin? The increasing use of anti-factor Xa activity to monitor the effect of UFH appears appropriate, given its moderate correlation with the UFH infusion rates, and it may play a role in preventing thromboembolic events. However, to avoid bleeding complications, more sophisticated tools, and careful clinical decision-making remain essential.

Association of Activated Clotting Time-Guided Anticoagulation with Complications during Extracorporeal Membrane Oxygenation Support: A Systematic Review and Meta-Analysis

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) requires systemic anticoagulation to reduce the risk of thromboembolic events. Despite its historic role, activated clotting time (ACT) remains a widely used heparin monitoring method. Systematic evidence on the association of ACT-guided monitoring with hemorrhagic or thromboembolic complications does not exist.

DESIGN

Systematic literature review and meta-analysis (Scopus and PubMed, July 2023).

SETTING

All cohort studies.

PARTICIPANTS

Patients receiving ECMO support.

INTERVENTION

Anticoagulation monitoring with ACT.

MEASUREMENTS AND MAIN RESULTS

We identified 3,177 publications, with 8 studies reporting the average ACT values for patients with and without bleeding. Meta-analysis revealed no significant difference in the compared groups (SMD = 0.69; 95% CI -0.05 to 1.43, p = 0.069; I2 = 87.4%). Three studies (n = 117 patients) reported on the average ACT values for patients with thrombosis, without significant differences in ACT between patients with and without thrombosis (SMD = 0.47; 95% CI -0.50 to 1.44, p = 0.342; I2 = 81.1%).

CONCLUSIONS

Even though ACT is a widely used heparin monitoring tool, the evidence on its association with hemorrhagic or thromboembolic events is still controversial and limited. Further studies are essential to elucidate the role of ACT in anticoagulation monitoring during ECMO support.

Anticoagulation Monitoring Using Activated Clotting Time in Patients Receiving Extracorporeal Membrane Oxygenation: A Meta-Analysis of Correlation Coefficients

OBJECTIVE

Extracorporeal membrane oxygenation (ECMO) requires systemic anticoagulation to maintain the circuit patency. However, the use of anticoagulation carries a risk of severe hemorrhage, necessitating rigorous monitoring. Activated clotting time (ACT) is a widely used monitoring tool; however, the evidence of its correlation with unfractionated heparin (UFH) infusion dose is limited. Here we aimed to analyze the correlation between ACT and UFH infusion during ECMO.

DESIGN

Systematic literature review and meta-analysis of correlation coefficients (Scopus and PubMed, up to July 13, 2024).

PROSPERO

CRD42023448888 SETTING: All retrospective and prospective studies PARTICIPANTS: Patients receiving ECMO support INTERVENTION: Anticoagulation monitoring during ECMO support MEASUREMENTS AND MAIN RESULTS: Nineteen studies were included in the analysis, and the meta-analysis encompassed 16 studies. The vast majority of studies (n = 15) found a weak correlation, and no study reported a strong correlation between ACT and UFH infusion dose. The meta-analysis (n = 12,625 samples) identified a weak correlation, with a pooled estimate of correlation coefficients of 0.132 (95% confidence interval 0.03-0.23). The most common adverse events were hemorrhage (pooled incidence, 45%) and thrombosis (30%), and 47% of the patients died during their hospital stay.

CONCLUSIONS

Even though ACT is a widely used UFH monitoring tool in ECMO patients, our meta-analysis found a weak correlation between ACT and UFH infusion dose. New trials are needed to investigate the role of emerging tools and to clarify the most appropriate monitoring strategy for patients receiving ECMO support.

ECMO in Myocardial Infarction-Associated Cardiogenic Shock: Blood Biomarkers as Predictors of Mortality

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (va-ECMO) can provide circulatory and respiratory support in patients with cardiogenic shock. The main aim of this work was to investigate the association of blood biomarkers with mortality in patients with myocardial infarction needing va-ECMO support.

METHODS

We retrospectively analyzed electronic medical charts from patients receiving va-ECMO support in the period from 2008 to 2021 at the Medical University Innsbruck, Department of Anesthesiology and Intensive Care Medicine.

RESULTS

Of 188 patients, 57% (108/188) survived to discharge, with hemorrhage (46%) and thrombosis (27%) as the most frequent adverse events. Procalcitonin levels were markedly higher in non-survivors compared with survivors during the observation period. The multivariable model identified higher blood levels of procalcitonin (HR 1.01, p = 0.002) as a laboratory parameter associated with a higher risk of mortality.

CONCLUSIONS

In our study population of patients with myocardial infarction-associated cardiogenic shock, deceased patients had increased levels of inflammatory blood biomarkers throughout the whole study period. Increased procalcitonin levels have been associated with a higher risk of mortality. Future studies are needed to show the role of procalcitonin in patients receiving ECMO support.

Extracorporeal Membrane Oxygenation (VA-ECMO) in Management of Cardiogenic Shock

Cardiogenic shock is a critical condition of low cardiac output resulting in insufficient systemic perfusion and end-organ dysfunction. Though significant advances have been achieved in reperfusion therapy and mechanical circulatory support, cardiogenic shock continues to be a life-threatening condition associated with a high rate of complications and excessively high patient mortality, reported to be between 35% and 50%. Extracorporeal membrane oxygenation can provide full cardiopulmonary support, has been increasingly used in the last two decades, and can be used to restore systemic end-organ hypoperfusion. However, a paucity of randomized controlled trials in combination with high complication and mortality rates suggest the need for more research to better define its efficacy, safety, and optimal patient selection. In this review, we provide an updated review on VA-ECMO, with an emphasis on its application in cardiogenic shock, including indications and contraindications, expected hemodynamic and echocardiographic findings, recommendations for weaning, complications, and outcomes. Furthermore, specific emphasis will be devoted to the two published randomized controlled trials recently presented in this setting.

Subtypes and Mechanistic Advances of Extracorporeal Membrane Oxygenation-Related Acute Brain Injury

Extracorporeal membrane oxygenation (ECMO) is a frequently used mechanical cardiopulmonary support for rescuing critically ill patients for whom conventional medical therapies have failed. However, ECMO is associated with several complications, such as acute kidney injury, hemorrhage, thromboembolism, and acute brain injury (ABI). Among these, ABI, particularly intracranial hemorrhage (ICH) and infarction, is recognized as the primary cause of mortality during ECMO support. Furthermore, survivors often suffer significant long-term morbidities, including neurocognitive impairments, motor disturbances, and behavioral problems. This review provides a comprehensive overview of the different subtypes of ECMO-related ABI and the updated advance mechanisms, which could be helpful for the early diagnosis and potential neuromonitoring of ECMO-related ABI.