While percutaneous transvalvular microaxial flow pumps improve hemodynamics, their clinical outcome benefits remain unproven in large RCTs and they carry significant risks of bleeding, hemolysis, and stroke.
The Impella device (Impella, Abiomed, Danvers, MA) is a percutaneous transvalvular microaxial flow pump that is currently used for (1) cardiogenic shock, (2) left ventricular unloading (combination of venoarterial extracorporeal membrane oxygenation and Impella concept), (3) high-risk percutaneous coronary interventions, (4) ablation of ventricular tachycardia, and (5) treatment of right ventricular failure. Impella-assisted forward blood flow increased mean arterial pressure and cardiac output, peripheral tissue perfusion, and coronary blood flow in observational studies and some randomized trials. However, because of the need for large-bore femoral access (14 F for the commonly used Impella CP device) and anticoagulation, the incidences of bleeding and ischemic complications are as much as 44% and 18%, respectively. Hemolysis is reported in as many as 32% of patients and stroke in as many as 13%. Despite the rapidly growing use of the Impella device, there are still insufficient data on its effect on outcome and complications on the basis of large, adequately powered randomized controlled trials. The only 2 small and also underpowered randomized controlled trials in cardiogenic shock comparing Impella versus intra-aortic balloon pump did not show improved mortality. Several larger randomized controlled trials are currently recruiting patients or are in preparation in cardiogenic shock (DanGer Shock Danish-German Cardiogenic Shock Trial; NCT01633502), left ventricular unloading (DTU-STEMI Door-To-Unload in ST-Segment-Elevation Myocardial Infarction; NCT03947619, UNLOAD ECMO Left Ventricular Unloading to Improve Outcome in Cardiogenic Shock Patients on VA-ECMO, and REVERSE A Prospective Randomised Trial of Early LV Venting Using Impella CP for Recovery in Patients With Cardiogenic Shock Managed With VA ECMO; NCT03431467) and high-risk percutaneous coronary intervention (PROTECT IV Impella-Supported PCI in High-Risk Patients With Complex Coronary Artery Disease and Reduced Left Ventricular Function; NCT04763200).
Lüsebrink et al. (Mon,) studied this question.
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