Comparison of Impella and VA-ECMO in Acute Myocardial Infarction-Related Cardiogenic Shock: Outcomes, Adverse Events, and Resource Demands

• Study Aim:
  • This study aimed to give contemporary insight into the use of Impella and venoarterial extracorporeal membrane oxygenation (VA-ECMO) in acute myocardial infarction-related cardiogenic shock (AMICS) and into associated outcomes, adverse events, and resource demands.
• Study Methods:
  • This nationwide observational cohort study describes all AMICS patients treated with Impella and/or VA-ECMO in 2020-2021.
  • Impella and/or VA-ECMO were used in 20% of all AMICS cases (n=4088).
  • The study found that Impella patients were older and less frequently presented after an out-of-hospital cardiac arrest.
  • In-hospital mortality was lower in the Impella versus VA-ECMO cohort.
  • Adverse events occurred less frequently in Impella-supported patients.
• Study Results:
  • Impella patients had a lower in-hospital mortality rate compared to VA-ECMO patients.
  • Adverse events such as acute haemorrhagic anaemia, cerebrovascular accidents, thromboembolisms of the extremities, systemic inflammatory response syndrome, acute kidney injury, and acute liver failure occurred less frequently in Impella-supported patients.
  • Impella patients were discharged home directly more often, while VA-ECMO patients were more often discharged to another care facility.
  • Impella patients had shorter hospital stays and lower hospital costs.
• Study Conclusion:
  • This is the largest, most recent European cohort study describing outcomes, adverse events, and resource demands based on claims data in patients with Impella and/or VA-ECMO.
  • Overall, adverse event rates and resource consumption were high.
  • The study reinforces the need for prospectively established, high-quality evidence to guide clinical decision-making in the treatment of AMICS.
• Introduction:
  • Studies have shown conflicting results regarding the use of mechanical circulatory support (MCS) in patients with acute myocardial infarction and cardiogenic shock.
  • While the routine use of an intra-aortic balloon pump (IABP) has been questioned, the use of Impella and/or venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been increasing rapidly.
• Previous Trials:
  • Several trials have demonstrated that Impella and VA-ECMO do not significantly improve survival in severe or rapidly deteriorating cardiogenic shock.
  • Extracorporeal cardiopulmonary resuscitation (eCPR) also did not significantly improve survival compared to conventional CPR in out-of-hospital cardiac arrests (OHCA).
• Adverse Events and Resource Demands:
  • Multiple retrospective studies have compared the adverse event rates of Impella and/or VA-ECMO.
  • A meta-analysis reported significantly lower in-hospital mortality for patients with Impella compared to VA-ECMO, but did not assess length of stay and healthcare costs.
• Objective of the Study:
  • This study aimed to provide current insights into the use of Impella and/or VA-ECMO in acute myocardial infarction and cardiogenic shock patients.
  • The study also aimed to evaluate clinical outcomes, adverse events, and resource demands associated with the use of these devices.
• Methods:
  • The study used retrospective cohort data from the Institute for the Hospital Remuneration System GmbH (InEK) database.
  • Baseline characteristics, procedures, outcomes, adverse events, and length of stay data were extracted for analysis.
  • Statistical analyses were performed using R Software.
• Results:
  • The study compared outcomes between Impella and VA-ECMO cohorts.
  • In-hospital mortality and discharge destinations were calculated.
  • Univariate comparisons for categorical variables were performed using the Pearson Chi-square test.
  • Odds ratios (OR) and confidence intervals (CI) were calculated for various outcomes.
• Length of Stay:
  • The study evaluated the index-hospital length of stay using weighted averages.
  • Mean and standard deviation were calculated for the Impella, VA-ECMO, and no device cohorts.
• Difference in Hospital Length of Stay:
  • There was a statistically significant difference in the index-hospital length of stay between the Impella and VA-ECMO cohorts.
  • This was tested using a two-tailed t-test tool for summary statistics.
• Cost Calculation:
  • Total costs per cohort were calculated by summing the overall DRG costs and the overall additional charges.
  • Average costs per patient and survivor were calculated by dividing the total in-hospital costs of a cohort by the number of patients or survivors in that cohort.
• General:
  • In 2020–2021, 8% of AMI cases were complicated by cardiogenic shock.
  • Impella was used in 13% of all AMICS patients, VA-ECMO was used in 5%, and 2% received haemodynamic support using both devices.
• Baseline and Cardiogenic Shock Characteristics:
  • Impella and VA-ECMO patients had comparable baseline characteristics.
  • Impella-supported patients were older and presented with an OHCA less often compared to VA-ECMO-supported patients.
• Hospital Stay:
  • Impella-supported patients required renal replacement therapy less often compared to VA-ECMO-supported patients.
  • Impella patients were also given fewer blood transfusions compared to VA-ECMO-supported patients.
• Mortality and Discharge Destination:
  • In-hospital mortality was higher in the Impella and VA-ECMO cohorts compared to the overall AMI cohort.
  • A higher percentage of AMICS patients required admission to another care facility after the initial treatment.
• Length of Stay:
  • The average index hospital length of stay of Impella-supported patients was shorter than that of VA-ECMO-supported patients.
  • The significant differences in length of stay between the Impella and VA-ECMO groups persisted even when analyzing only the surviving and discharged patients.
• Costs:
  • The average index in-hospital costs for an Impella-supported patient were lower compared to a VA-ECMO-supported patient.
  • The average index in-hospital costs per AMICS survivor supported by an Impella, VA-ECMO, or a combination of devices were calculated.