The Impella is a percutaneous left ventricular assist device (LVAD). Think of it as an IABP (Intra-Aortic Balloon Pump) on steroids. That’s not entirely accurate because it doesn’t augment coronary perfusion like the IABP does, but it’s close. It does unload the LV and assist the pumping of a failing heart. It can be inserted fairly quickly, either through the femoral or axillary artery and can be done in the cath lab or even at the bedside in some cases.
It comes in several sizes, with larger ones generating more flow. In addition to being used one it’s own, it’s nice when used in combination with peripheral VA ECMO. When inserted peripherally, VA ECMO generates retrograde flow through the aorta (the cannula is inserted into either the femoral artery or subclavian artery so blood flows through the aorta towards the heart) which can make a failing left ventricle fail even faster. An Impella can be inserted to offload the LV, somewhat counters the effects of the retrograde ECMO flow.
Count Backwards From 10 does a nice little review with illustrations.
critical care notes 