Anticoagulation and Bleeding during Veno-Venous Extracorporeal Membrane Oxygenation: Insights from the PROTECMO Study

Anticoagulation Monitoring Strategies During Extracorporeal Membrane Oxygenation (ECMO) Therapy - Differences Between Simultaneously Obtained Coagulation Tests: A Retrospective Single-Center Cohort Study

IntroductionDuring extracorporeal membrane oxygenation (ECMO) systemic anticoagulation with unfractionated heparin (UFH) is standard-of-care. However, there is uncertainty regarding optimal anticoagulation monitoring strategies.MethodsWe retrospectively investigated venovenous and venoarterial ECMO patients at the medical ICUs at the Medical University of Graz, Austria. We analyzed the correlation and concordance of R-time in thromboelastography (TEG), activated partial thromboplastin time (aPTT), and anti-Xa activity. The proportion within target range, the association of coagulation parameters above or below target range (aPTT 54-72 s; equals 1.5-2× upper limit of normal (ULN), anti-Xa activity 0.2-0.5 U/mL, and R-time in assays without heparinase 675-900 s; equals 1.5-2× ULN) with mortality, bleeding events and thrombotic complications were investigated.ResultsWe analyzed 671 clusters of simultaneously performed coagulation tests in 85 ECMO cases that fulfilled inclusion criteria. Median age of patients was 57 years and 32% were female. There were poor correlations between the three coagulation tests and the proportion of discordance was 46%. Within the target range were 21% of R-time, 15% of aPTT, and 44% of anti-Xa activity measurements. Singular and multiple bleeding events occurred in 25 and 32 patients, respectively. The most common bleeding locations were catheter and cannula insertion sites followed by pulmonary hemorrhage. In VA-ECMO, anti-Xa activity was associated (OR 1.03 [1.01-1.06], p = 0.005) and correlated with bleeding events (spearman rho 0.49, p = 0.002; point biserial 0.49, p = 0.001). aPTT level below target range was associated with reduced mortality (OR 0.98 [0.97-0.99], p = 0.024). Thrombotic events occurred in six patients with no association of coagulation tests.ConclusionThere was a high rate of discordance and poor correlation between aPTT, anti-Xa activity and R-time in TEG in ECMO patients. We found high rates of bleeding events and in VA-ECMO an association with elevated anti-Xa activity levels.

Year in Review 2024: Noteworthy Literature in Cardiothoracic Critical Care

This article reviews noteworthy additions to the literature for the management of critically ill cardiothoracic surgical patients published in 2024. We reviewed 8100 articles to identify 10 publications that provided new or updated information across a diverse range of topics including extracorporeal membrane oxygenation (ECMO), sepsis and shock, and acute hypoxemic respiratory failure (AHRF). Additional topics within these publications included prophylaxis guidelines and evidence for prevention of common complications in the intensive care unit, such as bleeding, thrombosis, and acute kidney injury (AKI).

Is an extended dose of subcutaneous nadroparin anticoagulation equally safe and feasible compared to unfractionated heparin anticoagulation during extracorporeal membrane oxygenation in critically ill COVID-19 patients?

INTRODUCTION

Unfractionated heparin (UFH) is the traditional anticoagulant of choice in critically ill COVID-19 patients requiring extracorporeal membrane oxygenation (ECMO). Nadroparin, a low molecular weight heparin, potentially offers advantages such as predictable pharmacokinetics and reduced bleeding risks compared to UFH, with complex pharmacokinetics, influencing activated partial thromboplastin and causing substantial haemorrhagic risks. Bleeding, the most common adverse event during ECMO, is associated by many with increased activated partial thromboplastin time.

MATERIAL AND METHODS

This retrospective, bicentric analysis involved 38 consecutive ECMO-supported COVID-19 patients from two Polish hospitals. The study compared 27 patients receiving UFH and 11 patients treated with 5700 IU of nadroparin administered subcutaneously twice daily. Thrombotic and haemorrhagic complications were assessed to determine the safety and feasibility of each anticoagulant.

RESULTS

Resistance to flow throughout the therapy in the ECMO membrane oxygenator was significantly lower in the group anticoagulated with UFH (1.74 mmHg × minute × L-1 [1.38-2.6] vs. 6.13 mmHg × minute × L-1 [5.93-14.81]; P < 0.001). However, the number of transfused red blood cell packs in the aforementioned group was significantly greater (10 units [5-17] vs. 4 units [2-8]; P = 0.027), and the haemoglobin level after ECMO therapy was significantly lower (7.8 g dL-1 [6.9-8.8] vs. 10.2 g dL-1 [8.5-12.2]; P = 0.003). Moreover, there was a higher number of life-threatening events in the UFH group.

CONCLUSIONS

UFH anticoagulation may provide better flow optimization in the oxygenator, but the risk of life-threatening bleeding may increase. The present findings need to be fully elucidated in prospective studies on a larger critically ill population supported with respiratory ECMO.

Characteristics of Bleeding Complications in Patients with Severe COVID-19 Requiring Veno-venous Extracorporeal Membrane Oxygenation in Japan

Complications during veno-venous extracorporeal membrane oxygenation (VV-ECMO) are associated with in-hospital mortality. Asian patients on extracorporeal membrane oxygenation (ECMO) have higher risks of bleeding and in-hospital mortality than Caucasian patients. This study aimed to characterize and identify bleeding complications and their associated factors related to in-hospital mortality in patients with severe coronavirus disease 2019 (COVID-19) requiring VV-ECMO in Japan.In this retrospective observational analysis, the prospective nationwide multicenter registry was used to track real-time information from intensive care units throughout Japan during the COVID-19 pandemic. VV-ECMO patients' registry data between February 1, 2020 and October 31, 2022 were used.This study included 441 patients; 178 (40%) had bleeding complications in the following sites: 20% at the cannulation site, 16% in the gastrointestinal tract, 16% in the ear-nose-throat, 13% at the tracheostomy site, 9% intrathoracic, 6% intracranial, and 5% in the iliopsoas. Anticoagulation was discontinued in >50% of patients with intracranial, iliopsoas, and gastrointestinal tract bleeding. ECMO was discontinued in one-third of patients with intracranial, intramuscular, and iliopsoas hemorrhages. Multivariable logistic regression analysis revealed that only gastrointestinal tract bleeding was associated with in-hospital mortality (odds ratio: 2.49; 95% confidence interval: 1.11-5.60; p = 0.03).Incidence of bleeding complications was 40% in the Japanese population. Gastrointestinal tract bleeding emerged as a significant predictor of adverse outcomes, necessitating further research into preventive strategies and optimized care protocols. These findings can guide the management of VV-ECMO patients with COVID-19.

Antithrombin during veno-venous extracorporeal membrane oxygenation with heparin anticoagulation: A single-center cohort study

IntroductionAntithrombin (AT) is a natural anticoagulant essential to enhancing the unfractionated heparin (UFH) anticoagulant effect. Its supplementation in the management of UFH-based anticoagulation during veno-venous extracorporeal membrane oxygenation (VV ECMO) has a strong pathophysiological rationale.MethodsThis is a single-center, retrospective cohort study of adult VV ECMO patients with anticoagulation maintained by UFH targeting an activated partial thromboplastin time (aPTT) of 40-50 s and AT activity >80%. We compare anticoagulation management and survival outcomes between AT subpopulations, defined by a threshold AT activity ≥80%. Linear and logistic regression analyses were used to evaluate the variation in AT activity and its association with ICU survival.ResultsIn 244 patients enrolled from 2009 to 2022, anticoagulation was maintained by a median heparin dose of 11.4 IU/kg/h [IQR: 8.2-14.7] with a mean aPTT of 46.1 s (±7.3) and AT activity of 88.9% (±17.0). A lower mean aPTT, higher dose of UFH and shorter fraction of time without UFH were associated with higher AT activity (p < .01). Higher AT activity showed a consistent association with ICU survival (for 10% increase of AT, odds ratio for ICU mortality: 0.95; 95% CI 0.93-0.97; p value <.01).ConclusionsThere is a positive association between AT activity and UFH requirements but no significant difference in the rate of bleeding events. A higher mean AT during VV ECMO was associated with ICU survival. Future studies are needed to differentiate between exogenously supplemented versus endogenous AT effect.

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.

Tough choices: the experience of family members of critically ill patients participating in ECMO treatment decision-making: a descriptive qualitative study

BACKGROUND

ECMO treatment for critically ill patients mostly requires family members to make surrogate decisions. However, the process and experience of family members' participation in decision making have not been well described.

PURPOSE

To explore the experience of family members of critically ill patients who were asked to consent to ECMO treatment and to gain insight into the factors that promote and hinder their decision-making.

METHODS

A descriptive qualitative study. Data were collected using a semi-structured interview method and analysed using traditional content analysis approaches. The cohort included nineteen family members of critically ill ICU patients from a general hospital in China.

RESULTS

Eleven family members consented to ECMO treatment, and 8 refused. 4 themes and 10 subthemes emerged: (1) tough choices: the dilemma in the emergency situation, the guilt and remorse after giving up; (2) rationalisation of decision-making: ethics and morality guide decision-making, expected efficacy influences decision making, and past experience promotes decision making; (3) decision-making methods: independent decision-making, group decision-making, decision making based on patient preferences; (4) influencing factors of decision making: information and communication, social support.

CONCLUSION

The findings provide insights and a basis for promoting efficient ECMO decision-making in clinical practice. It may be difficult to improve the time it takes to make the decision without sacrificing the quality of the decision. Healthcare professionals should provide timely emotional support, informational support, and comprehensive social support to assist them in making efficient decisions while respecting the treatment preferences of the decision-makers.

Improved Results Over Time With Bridge-to-Lung Transplantation: A 10-Year Experience of a Single High-Volume Center

When donor scarcity limits timely lung transplantation (LTx), extracorporeal membrane oxygenation (ECMO) as a bridge to transplantation (BTT) can prolong survival and delay deconditioning until the donor lungs become available. We reviewed 10-year BTT experiences of a single high-volume center, where 99 (59%) were on ECMO BTT among 169 eligible adult LTx cases. Both 28-day and 2-year survivals did not differ between BTT and non-BTT. The BTT data was then divided into two periods, delineated by the most recent 3 years. The clinical outcomes of the earlier period ("Period 1") and the later period ("Period 2") were compared, and mortality within 28 days of LTx was significantly lower in Period 2 (n = 1, 1.7%) than in Period 1 (n = 6, 14.6%, p < 0.01). Improved survival was observed in the subgroup with BTT duration of 14 days or more. Taken together, more experiences in BTT and improved competence may contribute to better survival after LTx, especially in patients receiving ECMO for 14 days or more.

Research progress on the pathogenesis of AKI complicated by ECMO

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) stands as a pivotal intervention for patients grappling with cardiopulmonary insufficiency. However, alongside its therapeutic benefits, ECMO carries the risk of complications, with acute kidney injury (AKI) emerging as a significant concern. The precise pathophysiological underpinnings of AKI in the context of ECMO remain incompletely elucidated.

METHODS

A comprehensive literature review was conducted to explore the epidemiology and pathophysiological mechanisms underlying the utilization of ECMO in the management of AKI.

RESULTS

ECMO initiates a multifaceted cascade of inflammatory reactions, encompassing complement activation, endothelial dysfunction, white blood cell activation, and cytokine release. Furthermore, factors such as renal hypoperfusion, ischemia-reperfusion injury, hemolysis, and fluid overload exacerbate AKI. Specifically, veno-arterial ECMO (VA-ECMO) may directly induce renal hypoperfusion, whereas veno-venous ECMO (VV-ECMO) predominantly impacts pulmonary function, indirectly influencing renal function.

CONCLUSION

While ECMO offers significant therapeutic advantages, AKI persists as a potentially fatal complication. A thorough comprehension of the pathogenesis underlying ECMO-associated AKI is imperative for effective prevention and management strategies. Moreover, additional research is warranted to delineate the incidence of AKI secondary to ECMO and to refine clinical approaches accordingly.

Anticoagulation Management for Veno-Venous ECMO in COVID-19 Patients: Argatroban as Rescue Therapy in Heparin-Associated Thrombocytopenia

Background/Objectives: Extracorporeal membrane oxygenation (ECMO) has been widely used as a life support technique in COVID-19 acute respiratory distress syndrome (ARDS). The use of anticoagulation during ECMO support remains a topic of debate. The primary aim of this study is to demonstrate the safety and efficacy of using argatroban as an anticoagulant instead of heparin in patients with heparin-associated thrombocytopenia. Methods: 40 patients were enrolled and initially treated with unfractionated heparin for anticoagulation during ECMO, composing the UFH group. Twenty-one of these patients experienced a drop in platelet count to below 100,000 cells/mm3 and, after testing negative for IgG anti-PF4/heparin, the anticoagulation was switched to argatroban, composing the ARG group. Hemorrhagic events were recorded along with blood chemistry parameters. Results: Bleedings were significantly more frequent in the UFH group than in ARG group (58/579 days vs. 21/357 days, p = 0.041). No significant differences were observed in hemorrhagic episodes for each bleeding site, except for tracheal stoma (14 vs. 1, p = 0.011). No differences in activated partial thromboplastin time (aPTT) values were found between the two groups (aPTT 42.65 s vs. 44.70 s, p = 0.443). Linear regression analysis revealed that the platelet count on day 5 was correlated with the initial platelet count but not with the type of anticoagulant used (p = 0.001, CI 0.55, 0.69 and p = 0.078). Linear regression analysis in both groups showed a correlation between the duration of ECMO support and intensive care unit stay for the median aPTT and median platelet count. Furthermore, no major systemic thrombotic events or circuit clotting were observed in this patient cohort. Conclusions: Argatroban seems to be safe in patients with persistent heparin-associated thrombocytopenia undergoing ECMO.

The early decline in platelet count is associated with increased adverse outcomes in non heparin-induced thrombocytopenia pediatric patients undergoing VA-ECMO

INTRODUCTION

The impact of non heparin-induced thrombocytopenia on the clinical outcomes for pediatric cardiac surgery patients who required veno-arterial extracorporeal membrane support (VA-ECMO) for failure to wean from cardiopulmonary bypass (CPB) is uncertain. This study aimed to investigate the relationship between thrombocytopenia and prognosis in these patients.

METHODS

This retrospective study enrolled 96 pediatric patients (age < 18) who received VA-ECMO directly transitioned from CPB at Fuwai Hospital from January 2010 to June 2020. The association between relative decrease in platelet count (△PLT) post-ECMO 24 h and clinical outcomes was explored.

RESULTS

There were significant differences in Post-ECMO 24 h platelet counts, platelet count nadir, and duration of platelet decline between the survivors and non-survivors in CPB-ECMO groups. A positive correlation was found between △PLT post-ECMO 24 h and plasma-free hemoglobin (pFHb) (p = .014, r = 0.305), peak serum creatinine (p = .016, r = 0.299), peak AST (p = .014, r = 0.302), duration of platelet transfusion (p = .032, r = 0.270),The △PLT post-ECMO 24 h had predictive value on in-hospital mortality [(p < .001, AUROC = 0.781 (95% CI: 0.670-0.892)], massive bleeding (p = .001, AUROC 95% CI: 0.627-0.870), hemolysis (p = .046, AUROC 95% CI: 0.510-0.780), and nosocomial infection (p = .020, AUROC 95% CI: 0.536-0.801). Multivariate logistic regression showed that △PLT post-ECMO 24 h was associated with in-hospital mortality and hemolysis.

CONCLUSIONS

The relative early decrease in platelet count 24 h following transition to ECMO is associated with increased patient mortality, and is positively associated with adverse outcomes in pediatric cardiac surgery patients transferred from CPB to ECMO. Moreover, this decline rate can predict in-hospital survival, major bleeding, hemolysis, and hospital-acquired infections.

Incidence of heparin resistance and heparin failure in patients receiving extracorporeal membrane oxygenation: an exploratory retrospective analysis

BACKGROUND

Unfractionated heparin (UFH) is used in most centers for extracorporeal membrane oxygenation (ECMO) anticoagulation. When standard doses do not achieve desired target values, heparin resistance is reported, most commonly defined as doses of UFH > 35 000 IU/d.

OBJECTIVES

To study the incidence of heparin resistance and its association with thromboembolic complications in patients requiring ECMO support.

METHODS

In this observational cohort study, we included adults who received venovenous, venoarterial ECMO and extracorporeal carbon dioxide removal between January 2010 and May 2022. Main risk factor was heparin resistance (UFH, > 35 000 IU/d or > 20 IU/kg/h); the outcome was thromboembolism. Multivariable Poisson regression was used to estimate the effects of heparin resistance, adjusted for several clinical variables on the thromboembolism rate per 100 ECMO patient-days.

RESULTS

Of the 197 patients included, 33 (16.8%) required UFH > 35 000 IU/d and 14 (7.1%) required UFH > 20 IU/kg/h. Thromboembolic complications occurred at a rate of 5.89/100 ECMO d. Heparin resistance was not associated with thromboembolic events (incidence rate ratio [IRR], 0.93; 95% CI, 0.14-5.82), whereas COVID-19 (IRR, 2.33; 95% CI, 1.4-3.96; P < .001) and ECMO type (venoarterial ECMO: IRR, 2.29; 95% CI, 1.34-3.92; P = .002; extracorporeal carbon dioxide removal: IRR, 2.89; 95% CI, 1.46-5.59; P = .002; reference venovenous ECMO) were significantly associated with the risk of thromboembolic events.

CONCLUSION

A significant proportion of patients fulfilled the common definition of heparin resistance. However, this did not influence the occurrence of thromboembolic events.

Metabolic support for patients on extra-corporeal membrane oxygenation

PURPOSE OF REVIEW

The purpose of the review is to summarize recent research on metabolic support during extracorporeal membrane oxygenation. In this review, we cover the evidence on nutritional supplementation, both the route of supplementation, timing of initiation of supplementation as well as quantities of supplementation needed. In addition, we discuss the recent trend in awake extracorporeal membrane oxygenation (ECMO) and its benefits to patients.

RECENT FINDINGS

As ECMO use continues to increase over the last few years, for both cardiovascular as well as respiratory failure, the need to optimize the metabolic states of patients has arisen. Increasing evidence has pointed towards this hitherto unexplored domain of patient care having a large impact on outcomes. Additionally, strategies such as awake ECMO for select patients has allowed them to preserve muscle mass which could aid in a faster recovery.

SUMMARY

There is a role of optimal metabolic support in the early recovery of patients on ECMO that is currently under-recognized. Future directions of research that aim to improve post ECMO outcomes must focus on this area.

ECMO management for severe pulmonary embolism with concurrent cerebral hemorrhage: a case report

Background

Acute pulmonary embolism (APE) is a common and potentially fatal cardiovascular disease that can lead to sudden cardiac arrest in severe cases. When conventional cardiopulmonary resuscitation measures fail to achieve the return of spontaneous circulation (ROSC) in patients with APE, venoarterial extracorporeal membrane oxygenation (ECMO) becomes a viable therapeutic option. As an advanced life support treatment, ECMO ensures the perfusion of critical organs, providing sufficient time for interventions necessary for ROSC.

Case introduction

We report the case of a patient who experienced cardiac arrest due to pulmonary embolism. During the treatment, the patient received two sessions of external cardiopulmonary resuscitation (ECPR) as supportive care and experienced cerebral hemorrhage. Ultimately, the patient improved and was discharged following support from extracorporeal membrane oxygenation (ECMO), careful anticoagulation strategies, and intervention with balloon pulmonary angioplasty.

Conclusion

ECMO can serve as an important life support technology for patients with severe APE. Through a cautious anticoagulation therapy, not only was the ECMO support successfully maintained but also was further deterioration of cerebral hemorrhage effectively prevented. For patients with concurrent main pulmonary artery embolism and bleeding, balloon pulmonary angioplasty may be an option.