Comparing Impella® to ECMO in AMICS

Alejandro Lemor, MD, MSc, discusses “Impella® versus Extracorporeal Membrane Oxygenation for Acute Myocardial Infarction Cardiogenic Shock,” a recently published paper in Cardiovascular Revascularization Medicine for which he was the first author. Dr. Lemor is chief cardiology fellow at Henry Ford Hospital in Detroit, MI, and a member of the National Cardiogenic Shock Initiative (NCSI) study and co-author on 3 publications from that database.

Dr. Lemor explains that he and his colleagues undertook this observational study of more than 6,000 admissions between 2015 and 2017 in order to look more deeply into the use of mechanical circulatory support (MCS) devices in AMI cardiogenic shock (AMICS) and compare use and outcomes with the 2 most commonly used devices: the Impella heart pump and extracorporeal membrane oxygenation (ECMO).

The authors used the National Inpatient Sample (NIS) database to identify hospital admissions undergoing percutaneous coronary intervention (PCI) and non-elective Impella or ECMO placement for AMI cardiogenic shock using ICD-10 codes. Patients receiving both Impella and ECMO were excluded so that the study could compare one device to the other and not the combination of both devices.

Dr. Lemor reviews baseline patient characteristics, most notably, the size of the Impella group, which was 10 times the size of the ECMO group. In addition, he discusses some markers of increased risk in the Impella group, including Impella patients being older and having more end-stage renal disease and more COPD. He shares his thoughts on these differences as well as potential reasons for the disparity in the size of the 2 groups.

Propensity matching was performed to compare both groups for primary and secondary outcomes. Propensity-match analysis revealed that the ECMO cohort had significantly higher in-hospital mortality (43.3% vs 26.7%) with a significant odds ratio of 2.10. In the Impella cohort, the rates of acute ischemic stroke were lower, and the incidence of acute respiratory failure and vascular complications were significantly lower.

“We did see an increased length of stay in those patients undergoing ECMO,” Dr. Lemor explains. “A median of 11 days in the ECMO cohort versus 7 days in Impella cohort. And also, higher hospital costs. Almost twice as much in the ECMO cohort versus the Impella cohort.”

Dr. Lemor concludes by stating, “Early identification of shock is very important and then selection of mechanical support device has a lot of factors that influence that… the degree of shock, vascular access, the baseline heart function, age, as well, and the respiratory status. So, I think the degree of comfort the operator has when placing one device or the other also has a lot of influence on which one to select.”