Influence of Timing and Predicted Risk on Mortality in Impella-Treated Infarct-Related Cardiogenic Shock Patients
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Updated: Dec 20, 2025
Utilizing Percutaneous Ventricular Assist Devices in Acute Myocardial Infarction Complicated by Cardiogenic Shock
Published on: June 12, 2021
Andreas Schäfer1, Nikos Werner2,3, Daniel Burkhoff4
1Cardiac Arrest Center & Advanced Heart Failure Unit, Department of Cardiology and Angiology, Hannover Medical School, Hanover, Germany.
Insights
In acute myocardial infarction-related cardiogenic shock (AMI-CS), the Impella pump showed lower-than-predicted mortality in high-risk patients. Early Impella implantation before percutaneous coronary intervention (PCI) was associated with better outcomes than later implantation.
Area of Science:
- Cardiology
- Interventional Cardiology
- Critical Care Medicine
Background:
- In-hospital mortality for acute myocardial infarction-related cardiogenic shock (AMI-CS) remains critically high.
- Routine intra-aortic balloon pump use has not demonstrated improved outcomes in AMI-CS.
- Novel circulatory support devices are being investigated for AMI-CS management.
Purpose of the Study:
- To evaluate the effectiveness of the Impella microaxial pump in AMI-CS patients.
- To compare observed mortality with predicted mortality using established risk scores (CardShock and IABP-Shock II).
- To assess the impact of Impella implantation timing (pre- vs. post-PCI) and patient risk stratification on outcomes.
Main Methods:
- Retrospective analysis of 166 consecutive AMI-CS patients treated with Impella, meeting IABP-Shock II trial criteria.
- Comparison of predicted 30-day mortality (CardShock and IABP-Shock II scores) against observed 30-day mortality.
- Subgroup analysis based on resuscitation status before Impella implantation and timing of implantation relative to PCI.
Main Results:
- Overall 30-day mortality was 42%, higher in resuscitated patients (50%) and those receiving Impella post-PCI (51%).
- No significant difference between predicted and observed mortality overall, but Impella showed significantly lower observed mortality in highest-risk patients (CardShock score: 51% vs. 77%).
- Impella implantation pre-PCI (28% mortality) was associated with significantly lower mortality than post-PCI implantation (51% mortality).
Conclusions:
- The Impella microaxial pump may be effective in selected high-risk AMI-CS patients.
- Risk stratification using scores like CardShock can identify patients who benefit most from Impella support.
- Timely Impella implantation, ideally before PCI, appears crucial for improving survival in AMI-CS.
Abstract:
Background: In-hospital mortality in acute myocardial infarction-related cardiogenic shock (AMI-CS) remains high. The only adequately powered randomized trial showed no benefit of routine use of the intra-aortic balloon pump in AMI-CS. We compared individually predicted mortality using CardShock- and IABP-Shock II-scores in AMI-CS patients treated with an Impella microaxial pump, who met the IABP-Shock II-trials inclusion/exclusion criteria, to observed mortality on circulatory support in order to determine whether standardized use of an Impella microaxial flow-pump in AMI-CS is associated with lower than predicted mortality rates and whether timing of implantation or selecting patients based on predicted risk is meaningful. Methods and Results: We analyzed data from 166 consecutive Impella-treated AMI-CS patients meeting the inclusion/exclusion criteria of the IABP-Shock II-trial (age 64 ± 11 years). Thirty-nine percentage of 64 patients had been resuscitated before Impella implantation. Overall 30-day mortality was 42%. Mortality was higher in resuscitated patients (50 vs. 36%, p = 0.0452) and when Impella was implanted post-PCI (Impella-pre-PCI: 28%, Impella-post-PCI: 51%, p = 0.0039). While in both score systems there was no significant difference between predicted and observed overall 30-day mortality, predicted mortality was significantly higher than observed mortality on Impella support only for individuals with highest predicted risk based on CardShock score (predicted 77 vs. observed 51%, p = 0.025). Conclusions: Our retrospective analysis suggests that the use of the Impella microaxial pump may be effective in selected cases of high risk patients with AMI-CS. Condensed abstract: Mortality is high in acute myocardial infarction-related cardiogenic shock despite rapid revascularization. Haemodynamic support with an intraortic balloon pump does not reduce mortality. In this retrospective registry including 166 consecutive IABP-Shock II-eligible cardiogenic shock patients in four dedicated shock centers, observed mortality on circulatory support with an Impella was significantly lower than predicted in patients with highest mortality risk. Implantation prior to PCI in acute myocardial infarction-related cardiogenic shock seemed to be associated with lower mortality than implantation post PCI.
