Eleven Years of Venovenous Extracorporeal Membrane Oxygenation for Acute Respiratory Distress Syndrome: From H1N1 to SARS-CoV-2. Experience and Perspectives of a National Referral Center

Anticoagulation strategies in patients with extracorporeal membrane oxygenation: A network meta-analysis and systematic review

OBJECTIVES

Extracorporeal membrane oxygenation (ECMO) plays an important role in providing temporary life support for patients with severe cardiac or pulmonary failure, but requires strict anticoagulation and monitoring. This network meta-analysis systematically explored the most effective anticoagulation and monitoring strategies for patients receiving ECMO.

METHODS

MEDLINE, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials were searched up to January 31, 2023, for studies comparing unfractionated heparin (UFH), argatroban (Arg), bivalirudin (Biv), and/or nafamostat mesylate (NM) in patients receiving ECMO. The primary outcomes included device-related thrombosis, patient-related thrombosis, and major bleeding events. The secondary outcomes included ECMO survival, ECMO duration, and in-hospital mortality.

RESULTS

A total of 2522 patients from 23 trials were included in the study. Biv was associated with a decreased risk of device-related thrombosis (odd ratio [OR] 0.51, 95% confidence interval [CI]: 0.33-0.84) compared with UFH, whereas NM (OR 2.2, 95% CI: 0.24-65.0) and Arg (OR 0.92, 95% CI: 0.43-2.0) did not reduce the risk of device-related thrombosis compared with UFH. Biv was superior to Arg in decreasing the risk of device-related thrombosis (OR 0.14, 95% CI: 0.03-0.51). Biv reduced the risk of patient-related thrombosis compared with UFH (OR 0.44, 95% CI: 0.18-0.85); NM (OR 0.65, 95% CI: 0.14-3.3) and Arg (OR 3.1, 95% CI: 0.94-12.0) did not decrease risk of patient-related thrombosis compared with UFH. No significant difference was observed in the risk of major bleeding between three alternatives and UFH: Biv (OR 0.54, 95% CI: 0.23-1.3), Arg (OR 1.3, 95% CI: 0.34-5.8), and NM (OR 0.60, 95% CI: 0.13-2.6). NM showed a reduced risk of in-hospital mortality compared with UFH (OR 0.27, 95% CI: 0.091-0.77), whereas Arg (OR 0.43, 95% CI: 0.15-1.2) and Biv (OR 0.75, 95% CI: 0.52-1.1) did not decrease risk of in-hospital mortality.

CONCLUSIONS

Compared with UFH and Arg, Biv reduces the risk of thrombosis and appears to be a better choice for patients requiring ECMO. NM was associated with a reduced risk of in-hospital mortality.

Extracorporeal membrane oxygenation in COVID-19 compared to other etiologies of acute respiratory failure: A single-center experience

BACKGROUND

The COVID-19 pandemic has led to a boom in the use of V-V ECMO for ARDS secondary to COVID. Comparisons of outcomes of ECMO for COVID to ECMO for influenza have emerged. Very few comparisons of ECMO for COVID to ECMO for ARDS of all etiologies are available.

OBJECTIVES

To compare clinically important outcome measures in recipients of ECMO for COVID to those observed in recipients of ECMO for ARDS of other etiologies.

METHODS

V-V ECMO recipients between March 2020 and March 2022 consisted exclusively of COVID patients and formed the COVID ECMO group. All patients who underwent V-V ECMO for ARDS between January 2014 and March 2020 were eligible for analysis as the non-COVID ECMO comparator group. The primary outcome was survival to hospital discharge. Secondary outcomes included ECMO decannulation, ECMO duration >30 days, and serious complications.

RESULTS

Thirty-six patients comprised the COVID ECMO group and were compared to 18 non-COVID ECMO patients. Survival to hospital discharge was not significantly different between the two groups (33% in COVID vs. 50% in non-COVID; p = 0.255) nor was there a significant difference in the rate of non-palliative ECMO decannulation. The proportion of patients connected to ECMO for >30 days was significantly higher in the COVID ECMO group: 69% vs. 17%; p = 0.001. There was no significant difference in serious complications.

CONCLUSION

This study could not identify a statistically significant difference in hospital survival and rate of successful ECMO decannulation between COVID ECMO and non-COVID ECMO patients. Prolonged ECMO may be more common in COVID. Complications were not significantly different.

Comparison of Bivalirudin Versus Heparin for Anticoagulation During Extracorporeal Membrane Oxygenation

The effect and safety of bivalirudin compared with heparin in patients undergoing extracorporeal membrane oxygenation (ECMO) remains unclear. Therefore, we conducted a systematic review and meta-analysis to compare the effectiveness and safety of heparin and bivalirudin in patients who underwent ECMO. We searched Embase, the Cochrane Central Register of Controlled Trials, and MEDLINE. Inclusion criteria included patients (1) undergoing ECMO and (2) receiving bivalirudin or heparin. We excluded studies where the majority of patients switched heparin to bivalirudin or vice versa during the clinical course. The primary outcome was short-term mortality. We presented the results of all analyses with the use of random-effects models. Eleven studies reported short-term mortality. The use of bivalirudin was associated with significantly lower short-term mortality, compared with heparin (odds ratio: 0.71, 95% confidence interval, 0.55-0.92; p = 0.01, I2 = 7%). In this meta-analysis of observational studies, the use of bivalirudin was associated with significantly lower short-term mortality, compared with heparin. Further prospective studies are warranted to clarify this finding.

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 ).

Direct Thrombin Inhibition in Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is a widely used technique to provide circulatory and/or respiratory support in critically ill patients. ECMO treatment usually necessitates systemic anticoagulation. Unfractionated Heparin (UFH) is a commonly used anticoagulant in patients on ECMO support. In situations where UFH is contraindicated, alternative anticoagulation strategies can be applied, such as the use of direct thrombin inhibitors (DTI). Bivalirudin and argatroban are the most widely used DTIs. In this report we give account of the current evidence regarding dosing, monitoring and complications associated with the use of these agents in ECMO dependent patients.