Microaxial flow pump for high-risk PCI: are we ready for the prime time?

The Impella device (Abiomed) is a percutaneous transvalvular microaxial flow pump which traverses the aortic valve and pumps blood from the left ventricle (LV) to the ascending aorta. The percutaneous LV Impella systems include the Impella Cardiac Power (CP) and Impella CP SmartAssist, providing up to 3.5 l/min and 4.3 l/min (based on the manufacturer information) using a 14 Fr initial introducer sheath1. This degree of haemodynamic support makes the Impella an attractive adjunct when performing high-risk percutaneous coronary interventions (PCI), which could prevent hypotension or even the development of cardiogenic shock by maintaining cardiac output; it may also facilitate a better outcome in more complex interventions. However, to support such a strategy, evidence derived from randomised clinical trials (RCTs) is needed, since any intervention using large-bore access may also cause harm. The current endorsement for Impella-assisted high-risk PCI is largely based on observational registries, where the decision to utilise the device was driven by a variety of factors beyond carefully defined clinical indications. This article will address the current evidence and clinical practice as well as ongoing RCTs...