ECMO, AMI Cardiogenic Shock
ECMELLA/ECpella versus ECMO
Benedikt Schrage, MD is one of the first to publish his experience with ECMO and Impella®—a combination known as “ECpella™” in the US and “ECMELLA” in Europe. Dr. Schrage, an interventional cardiologist in Hamburg, Germany, is the first author on a recently published paper in Circulation titled “Left Ventricular Unloading is Associated with Lower Mortality in Cardiogenic Shock Patients Treated with Veno-arterial Extracorporeal Membrane Oxygenation – Results from an International, Multicenter Cohort Study.”
Dr. Schrage acknowledges that while ECMO is a lifesaving therapy for severe cardiogenic shock, it significantly increases LV afterload, noting, “from a hemodynamic point of view, as the ECMO retrogradely perfuses the aorta, we do know that this leads to increased LVEDP, increased pressure inside the left ventricle, which can then hamper myocardial recovery.” This is the rationale, he states, for implanting an Impella heart pump for “active LV unloading” in addition to ECMO.
“Impella active LV unloading not only provides you with a chance to increase the probability of LV recovery,” Dr. Schrage explains, “but you also get a chance to wean the ECMO faster… And we do know that shortening time on ECMO also decreases the risk of complications.”
Dr. Schrage’s paper, based on a retrospective database with propensity score matching to help create more comparable groups, represents the largest ECMELLA experience in the world. Dr. Schrage highlights key take home messages from the figures in the paper.
- Figure 2 reveals “a significant association between the use of this active LV unloading and a lower mortality.”
- Figure 3 shows “the association between active LV unloading and lower mortality was quite consistent through all the subgroups that we tested.”
- In Figures 4 and 5, “although we saw the higher survival with the active LV unloading in our study, we also saw more complications, we saw more severe bleeding, and more ischemia related to the access site.” This, he notes, may be illustrative of a survivor bias, explaining, “when you live longer you have a higher risk to live until you get complications.”
- In Figure 6, Dr. Schrage notes that it was intriguing that ECMELLA patients treated with early LV unloading showed a statistically significant reduction in mortality while the delayed LV unloading curves did not; however, he believes it was likely an issue of insufficient statistical power. “Overall, I think one could say that even delayed unloading might be better than no unloading, if it’s not too late.”
“I would say the striking thing to take away from this paper is that this supports the overall approach to LV unloading in patients on ECMO,” Dr. Schrage explains. “Although this is retrospective data, not randomized, it gives a certain rationale to this approach that active LV unloading might improve myocardial recovery and facilitate and improve ECMO weaning and thereby benefit the patients.” He also emphasizes, “we need to do everything to reduce the complications so that more patients might benefit from this and really identify those who are the best candidates.”
Dr. Schrage concludes the interview by briefly discussing practical strategies for moving forward as we await more data. He emphasizes that for clinicians who understand how to use Impella “this is a great opportunity to address the increase in LV afterload caused by ECMO.” He explains that the choice of Impella device depends on the patient and the patient situation and he notes that it is important to minimize complications by following good access techniques, including ultrasound, micropuncture, and femoral angiography.