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Treatment with Impella and Venoarterial Extracorporeal Membrane Oxygenation During Cardiac Arrest Improves Survival: A Multicentre Cohort Study

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Support: The development of this supplement was funded by Abiomed.

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Dr Thevathasan’s work focuses on comparing outcomes of venoarterial extracorporeal membrane oxygenation (VA-ECMO) with VA-ECMO combined with Impella (ECMELLA or ECpella) in patients with cardiac arrest. Past studies in this field have demonstrated that extracorporeal cardiopulmonary resuscitation (ECPR) offers a survival benefit over traditional cardiopulmonary resuscitation (CPR).1 Despite a 10-fold increase in ECPR usage from 2003 to 2014, overall survival has remained unchanged at approximately 29%.2 Although studies such as the ARREST trial showed significant survival increases with ECPR,3 a prospective registry study from the same year revealed virtually identical survival rates between ECPR and conventional CPR,4 suggesting there are unknown factors involved with the effect of ECPR on survival after a cardiac arrest. Dr Thevathasan aimed to answer these questions by conducting a cohort study of cardiac arrest patients in three tertiary care centres in Berlin over the past 5 years.

Dr Thevathasan and his team hypothesised that the type of ECPR may affect survival outcome. Adult patients with cardiac arrest due to acute MI who were treated with either VA-ECMO or ECMELLA were propensity matched for age, location of cardiac arrest, ECG rhythm and the IABP-SHOCK II score. The primary outcome was 30-day mortality, and secondary outcomes were the lengths of hospital and intensive care unit (ICU) stay. Overall, the cohort of 95 patients had a mean age of 64, with 60% of patients having an in-hospital cardiac arrest; patients had a SAVE score of −9 and relatively few comorbidities, with a Charlson comorbidity index (CCI) of 3. After propensity matching, the ECMELLA group had a 50% lower 30-day mortality risk than patients treated with VA-ECMO alone. Both the hospital and ICU lengths of stay were 50% longer in the ECMELLA group, which can be attributed to the increased survival of this patient group. Multivariate analysis revealed that ECMELLA therapy improved survival in patients who were male, aged ≤75 years, experienced in-hospital cardiac arrest, scored <3 on the CCI or had a greater than Class IV SAVE score. Interestingly, physician experience also played a role, because patients treated by an experienced cardiologist (defined as having treated three or more ECPR cases) also had lower mortality. Together, these findings suggest that ECPR offers significant survival improvements, and that certain patient characteristics are associated with the best outcomes of ECMELLA therapy.

Similar to previous reports in cardiogenic shock, one of the most frequent complications observed with both therapies in this study was critical bleeding, defined as a drop in haemoglobin of ≥5 g/dL. This complication is likely attributed to the large cannula used for devices, as well as anticoagulation and antiplatelet therapies used after percutaneous coronary intervention. Haemolysis trended higher in the ECMELLA group, likely due to the inlet–outlet interactions and continuous blood flow through the Impella device. These effects have been reported in studies of cardiogenic shock, but not previously in cardiac arrest.5

Dr Thevathasan summarised that LV unloading with Impella in patients treated with VA-ECMO was associated with lower mortality rates during ECPR, and that a randomised controlled clinical trial is vital to further evaluate the benefits of left ventricular unloading in patients with therapy-refractory cardiac arrest.

References

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  2. Richardson ASC, Schmidt M, Bailey M, et al. ECMO cardio-pulmonary resuscitation (ECPR), trends in survival from an international multicentre cohort study over 12-years. Resuscitation 2017;112:34–40.
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    Crossref | PubMed