The Role of Impella in Cardiogenic Shock in the Post-DanGer Shock Era

Abstract

The microaxial flow pump (mAFP) is a mechanical circulatory support device designed to directly unload the left ventricle, restore cardiac output, and improve systemic perfusion in the setting of cardiogenic shock (CS). CS is a devastating complication of acute myocardial infarction (AMI) and advanced heart failure, characterized by systemic hypoperfusion and myocardial dysfunction, carrying an in-hospital mortality of 30-50%. However, there has been controversy about whether these theoretical physiological mechanisms behind mAFP translate into actual survival or recovery in this patient population that has historically been difficult to study in prospective trials. The lack of consensus has resulted in differing national guidelines, resource allocation, and clinical decision-making in time-sensitive clinical scenarios. Earlier studies were limited to retrospective analyses and a single small, underpowered randomized trial, none of which showed a mortality benefit. In 2024, the DanGer Shock trial emerged as the first multi-center trial to demonstrate mortality benefit in patients with STEMI complicated by CS treated with Impella CP, albeit at the cost of increased risk of major bleeding, hemolysis, and vascular complications, an effect sustained in the 10 year outcomes published in 2025. In this review, we examine reasons for the differing results of preceding studies and compare how multinational guidelines have reacted to this new evidence. Finally, we provide practical considerations regarding the use, complications, and troubleshooting of this technology, and identify gaps in evidence regarding patient selection and timing of placement.

Keywords: Impella; cardiogenic shock; mechanical circulatory support; microaxial flow pump; myocardial infarction.

Figure 1

Effects of cardiogenic shock and mechanical circulatory support on LV Pressure–Volume (PV) loops. Top panel: Reduced contractility and increased filling pressures seen in the PV loop of cardiogenic shock (red loop) compared to normal physiology (black loop). This results from a rightward shift in the End-Systolic Pressure-Volume Relationship (ESPVR) and an upward shift in the End-Diastolic Pressure-Volume Relationship (EDPVR). Bottom panel: Mechanical support devices alter PV loop geometry—Impella unloads the LV, IABP modestly improves hemodynamics, and VA-ECMO increases afterload unless combined with unloading. Bottom strip: While the Impella facilitates flow the LV to the aorta, the IABP facilitates flow from the proximal aorta to the descending aorta, and VA-ECMO facilitates flow from the right atrium to the aorta. Original illustration created in BioRender (2025). https://biorender.com/7ehqejy.

Figure 2

Overview of commonly used Impella devices. Visual comparison of Impella CP, 5.5, and RP. CP and 5.5 provide left-sided support from the LV to the aorta, differing in access method, pump design, and flow capacity. Original illustration created in BioRender. (2025) https://BioRender.com/2z03vvl.

Figure 3

Evolution of Impella device approvals and clearances and major clinical trials. Timeline depicting CE and FDA approvals and clearances (top) alongside landmark clinical trials (bottom) evaluating mAFP use in high-risk PCI and CS, culminating in the pivotal DanGer Shock trial and future studies. ↓: Decrease; ↑: Increase; (-): Negative outcomes. (+): Positive outcomes. Original illustration created in BioRender. (2025) https://BioRender.com/33pq6rq.

Figure 4

Impella placement screen with pressure and motor waveform tracings. Display panel showing real-time Impella placement signals. Red waveform reflects aortic pressure, white waveform indicates LV pressure, and green waveform represents motor current. Original illustration created in BioRender. (2025) https://BioRender.com/l1fke15.

Figure 5

Verifying correct placement of the Impella CP device on transthoracic echocardiography. For reader understanding, this echocardiogram is provided unannotated (left panel) and annotated (right panel). Abbreviations: Ao = aorta, LV = Left ventricle, LA = left atrium, MV = mitral valve, RV = right ventricle. Original illustration created in BioRender. (2025) https://BioRender.com/d86wclk.

Figure 6

Shallow Impella CP position on echocardiography. PLAX view showing shallow malposition of the Impella with the inlet too close to the aortic valve, unannotated (left panel) and annotated (right panel). Abbreviations: Ao = aorta, LV = Left ventricle, LA = left atrium, RV = right ventricle. Original illustration created in BioRender. (2025) https://BioRender.com/y43v9a1.