A Comparison of Anticoagulation Strategies in Veno-venous Extracorporeal Membrane Oxygenation

Evaluation of an aPTT guided versus a multimodal heparin monitoring approach in patients on extra corporeal membrane oxygenation: A retrospective cohort study

IntroductionBleeding and thrombotic complications are common in extracorporeal membrane oxygenation (ECMO) patients and are associated with increased mortality and morbidity. The optimal anticoagulation monitoring protocol in these patients is unknown. This study aims to compare the incidence of thrombotic and hemorrhagic complications before and after a protocol change. In addition, the association between hemostatic complications, coagulation tests and risk factors is evaluated.MethodsThis is a retrospective single center cohort study of adult ECMO patients. We collected demographics, ECMO parameters and coagulation test results. Outcomes of the aPTT guided and multimodal protocol, including aPTT, anti-Xa assay and rotational thromboelastometry were compared and the association between coagulation tests, risk factors and hemostatic complications was determined using a logistic regression analysis for repeated measurements.ResultsIn total, 250 patients were included, 138 in the aPTT protocol and 112 in the multimodal protocol. The incidence of thrombosis (aPTT: 14%; multimodal: 12%) and bleeding (aPTT: 36%; multimodal: 40%), did not significantly differ between protocols. In the aPTT guided protocol, the aPTT was associated with thrombosis (Odds Ratio [OR] 1.015; 95% confidence interval [CI] 1.004-1.027). In both protocols, surgical interventions were risk factors for bleeding and thrombotic complications (aPTT: OR 93.2, CI 39.9-217.6; multimodal OR 17.5, CI 6.5-46.9).DiscussionThe incidence of hemostatic complications was similar between both protocols and surgical interventions were a risk factor for hemostatic complications. Results from this study help to elucidate the role of coagulation tests and risk factors in predicting hemostatic complications in patients undergoing ECMO support.

Anticoagulation management during veno-venous ECMO support because of ARDS: Single-center experience

Background

Patients with severe acute respiratory distress syndrome (ARDS) show a high mortality rate of up to 60 %. In such cases, extracorporeal membrane oxygenation (ECMO) support is often required, which would necessitate anticoagulation therapy, predominantly with heparin. Some bleeding events occurred more frequently in patients during the COVID-19 pandemic who were on venovenous (V-V) ECMO, so it is necessary to investigate whether anticoagulation management should be adjusted.

Methods

We collected data on 90 patients with severe ARDS who underwent ECMO support at the University Hospital Magdeburg between 2014 and 2022. In order to estimate the role of anticoagulation therapy as a cause of bleeding, patients were divided into two groups based on their mean activated partial thromboplastin time (aPTT): one group with a mean aPTT of more than 58 s (45 patients) and another with a mean aPTT of less than 58 s (45 patients). Demographic data, data before, during ECMO support, and bleeding complications were retrospectively recorded. We compared laboratory parameters before ECMO, essential coagulation parameters on days 3, 7, 10 of ECMO support, before the bleeding event occurred, and analyzed hospital survival in both groups.

Results

The incidence of major bleeding complications was significantly higher in the group of patients with higher aPTT (68.9 % vs 33.3 %, p < 0.001), the differences in the occurrence of hemothorax were especially significant (28.9 % vs 2.2 %, p < 0.001). We observed better hospital patients' survival in the group with lower aPTT (40.0 % vs 68.9 %, p = 0.006). The results of the bivariate analysis indicate that the independent predictors of hospital mortality in adult patients receiving V-V ECMO support due to severe ARDS were COVID-19 (OR: 3.504; 95 % confidence interval [CI]: 1.415-8.681, p = 0.007) acute liver failure (OR: 8.0000; 95 % CI: 1.692-37.822; p = 0.009), high antithrombin level (%) (OR: 1.036; 95 % CI: 1.003-1.071, p = 0.035). A high mean aPTT level increased the risk of major bleeding (OR: 1.080; 95 % CI: 1.016-1.148, p = 0.014) without a significant increase in mortality.

Conclusion

Prolonged aPTT during V-V ECMO support in patients with ARDS significantly impacts the risk of major bleeding, especially hemothorax, without significant increase in hospital mortality.

Inferior vena cava thrombosis in patients undergoing extracorporeal membrane oxygenation: a case series and literature review

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is mainly used for support of patients with cardiopulmonary collapse. The increasing use of ECMO has shown promising outcomes; however, it still carries the risk of significant complications. Inferior vena cava (IVC) thrombosis is an underestimated complication.

METHODS

We described a series of 5 ECMO patients diagnosed with IVC thrombosis in our institution. An electronic literature search of the PubMed, Cochrane Library and Web of Science databases. A total of 12 cases were identified.

RESULTS

The occurrence of IVC thrombosis in ECMO patients is not uncommon. In our case series, elevated CRP and PCT levels and activated partial thromboplastin times (aPTT) of less than 50 s during ECMO operation were observed. In the literature review, a higher proportion of veno-arterial (VA) ECMO application (67%; 8/12) was presented in patients with IVC thrombosis. Eight patients (73%; 8/11) were monitored for anticoagulation using either aPTT or a combination of aPTT and ACT, with all aPTT measurements achieving the target range for anticoagulation. The mainstay of treatment for IVC thrombosis was anticoagulation alone (75%; 9/12). After the treatment, IVC thrombosis disappeared in the majority of patients (75%; 9/12) and there was no thrombosis-related mortality.

CONCLUSION

Factors such as elevated CRP and PCT levels, low aPTT levels, and the use of VA ECMO may contribute to the development of ECMO-related IVC thrombosis. Monitoring of anticoagulation with aPTT alone or in combination with ACT during ECMO may have inherent limitations. Anticoagulation alone may be an effective treatment for IVC thrombosis.

Infection in ECMO patients: Changes in epidemiology, diagnosis and prevention

Patients with prolonged duration of extracorporeal membrane oxygenation support (ECMO) are a vulnerable population for sepsis, particularly ventilator-associated pneumonia and bloodstream infections. Rates differ between venous-arterial and venous-venous ECMO patients and according to the cannulation technique used. The presence of particular organisms depends on local epidemiology, antibiotic exposure, and the duration of the intervention; patients undergoing ECMO for more than three weeks present a high risk of persistent candidemia. Recognizing predisposing factors, and establishing the best preventive interventions and therapeutic choices are critical to optimizing the management of these complications. Infection control practices, including shortening the period of the indwelling devices, and reducing antibiotic exposure, must be followed meticulously. Innovations in oxygenator membranes require an updated approach. Hand hygiene and avoiding breaking the circuit-oxygenator sterility are cornerstones. ECMO management would benefit from clearer definitions, optimization of infection control strategies, and updated infectious clinical practice guidelines.

The Year in Coagulation and Transfusion: Selected Highlights from 2022

This is an annual review to cover highlights in transfusion and coagulation in patients undergoing cardiovascular surgery. The goal of this article is to provide readers with a focused summary of the most important transfusion and coagulation topics published in 2022. This includes a discussion covering the management of anemia and red blood cell transfusion, the management of factor Xa inhibitors, updates in coagulation testing, updates in the use of factor concentrates, advances in platelet therapy, advances in anticoagulation management of patients on extracorporeal membrane oxygenation and other forms of mechanical circulatory support, and advances in the diagnosis and management of heparin-induced thrombocytopenia.

Outcomes of patients with coronavirus disease versus other lung infections requiring venovenous extracorporeal membrane oxygenation

Background

Patients with Coronavirus Disease (COVID-19) often develop severe acute respiratory distress syndrome (ARDS) requiring prolonged mechanical ventilation (MV), and venovenous extracorporeal membrane oxygenation (V-V ECMO).Mortality in COVID-19 patients on V-V ECMO was exceptionally high; therefore, whether survival can be ameliorated should be investigated.

Methods

We collected data from 85 patients with severe ARDS who required ECMO support at the University Hospital Magdeburg from 2014 to 2021. The patients were divided into the COVID-19 group (52 patients) and the non-COVID-19 group (33 patients). Demographic and pre-, intra-, and post-ECMO data were retrospectively recorded. The parameters of mechanical ventilation, laboratory data before using ECMO, and during ECMO were compared.

Results

There was a significant difference between the two groups regarding survival: 38.5% of COVID-19 patients and 63.6% of non-COVID-19 patients survived 60 days (p = 0.024). COVID-19 patients required V-V ECMO after 6.5 days of MV, while non-COVID-19 patients required V-V ECMO after 2.0 days of MV (p = 0.048). The COVID-19 group had a greater proportion of patients with ischemic heart disease (21.2% vs 3%, p = 0.019). The rates of most complications were comparable in both groups, whereas the COVID-19 group showed a significantly higher rate of cerebral bleeding (23.1 vs 6.1%, p = 0.039) and lung bacterial superinfection (53.8% vs 9.1%, p = <0.001).

Conclusion

The higher 60-days mortality among patients with COVID-19 with severe ARDS was attributable to superinfection, a higher risk of intracerebral bleeding, and the pre-existing ischemic heart disease.

Comparison of anticoagulation monitoring strategies for adults supported on extracorporeal membrane oxygenation: A systematic review

BACKGROUND

Anticoagulation is critical in patients supported on extracorporeal membrane oxygenation (ECMO). The appropriate monitoring strategies for heparin remain unclear.

OBJECTIVES

This systematic review aimed to compare the accuracy and safety of various monitoring strategies for patients supported on ECMO.

METHODS

The PubMed and Web of Science databases were searched for articles in March 2023 without restrictions on publication date. Anticoagulation monitoring strategies for adults supported on ECMO were compared across all included studies. The incidence of bleeding, thrombosis, mortality, blood transfusion, correlation between tests and heparin dose, and the discordance between different tests were discussed in the included studies. The risk of bias was assessed using the Newcastle-Ottawa Scale and Cochrane Collaboration's tool.

RESULTS

Twenty-six studies, including a total of 1,684 patients, met the inclusion criteria. The monitoring of anticoagulation by activated partial thromboplastin time (aPTT) resulted in less blood product transfusion than that by activated clotting time (ACT). Moreover, the monitoring of anticoagulation by anti-factor Xa (Anti-Xa) resulted in a more stable anticoagulation than that by aPTT. Anti-Xa and aPTT correlated with heparin dose better than ACT, and the discordance between different monitoring tests was common. Finally, combined monitoring showed some advantages in reducing mortality and blood product transfusion.

CONCLUSION

Anti-Xa and aPTT are more suitable for anticoagulation monitoring for patients supported on ECMO than ACT. Thromboelastography and combination strategies are less applied. Most of the studies were retrospective, and their sample sizes were relatively small; thus, more appropriate monitoring strategies and higher quality research are needed.

Reduced anticoagulation targets in extracorporeal life support (RATE): study protocol for a randomized controlled trial

BACKGROUND

Although life-saving in selected patients, ECMO treatment still has high mortality which for a large part is due to treatment-related complications. A feared complication is ischemic stroke for which heparin is routinely administered for which the dosage is usually guided by activated partial thromboplastin time (aPTT). However, there is no relation between aPTT and the rare occurrence of ischemic stroke (1.2%), but there is a relation with the much more frequent occurrence of bleeding complications (55%) and blood transfusion. Both are strongly related to outcome.

METHODS

We will conduct a three-arm non-inferiority randomized controlled trial, in adult patients treated with ECMO. Participants will be randomized between heparin administration with a target of 2-2.5 times baseline aPTT, 1.5-2 times baseline aPTT, or low molecular weight heparin guided by weight and renal function. Apart from anticoagulation targets, treatment will be according to standard care. The primary outcome parameter is a combined endpoint consisting of major bleeding including hemorrhagic stroke, severe thromboembolic complications including ischemic stroke, and mortality at 6 months.

DISCUSSION

We hypothesize that with lower anticoagulation targets or anticoagulation with LMWH during ECMO therapy, patients will have fewer hemorrhagic complications without an increase in thromboembolic complication or a negative effect on their outcome. If our hypothesis is confirmed, this study could lead to a change in anticoagulation protocols and a better outcome for patients treated with ECMO.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04536272 . Registered on 2 September 2020. Netherlands Trial Register NL7969.