Additional Study Information: The purpose of this study is to find out whether an experimental device, called HeartMate PHP, can safely help maintain blood flow during angioplasty, and to compare it to an FDA approved device called Impella. This study will also evaluate the safety and efficacy of the HeartMate Percutaneous Heart Pump (HeartMate PHP) when used in patients who are undergoing percutaneous coronary intervention (PCI) procedures, such as angioplasty (a procedure done to open narrow or blocked heart arteries) and/or stent placement (a wire or mesh tube that expands to hold the artery open). PCI is a treatment procedure that unblocks narrowed coronary arteries without performing surgery. Some patients who undergo PCI have reduced pumping power of the heart, and/or other heart disease which puts them at higher risk for potential problems during PCI. In this study, the HeartMate PHP is used as a heart assist device to test its safety to provide support for the left side of your heart while you undergo PCI.