SHIELD II Clinical Investigation

Prospective, randomized, multi-center, open-label trial of the HeartMate PHP at up to 120 sites in the United States (U.S.). Control device will be any Abiomed Impella device approved for use in high-risk PCI. This clinical investigation is divided into two phases, a feasibility phase and a pivotal phase. * Feasibility Phase: Includes 75 roll-in and 120 randomized subjects registered under the clinical investigational plan (CIP) versions 2-4 at 48 sites in the U.S. prior to January 30, 2017 * Pivotal Phase: Includes subjects to be registered under Version F or a later version of the CIP at up to 120 sites in the U.S. Non-randomized Roll-in Cohort: Up to 480 subjects with the HeartMate PHP. Randomized Cohort: A minimum of 473 and a maximum of 716 subjects will be randomized in a 2:1 ratio to the HeartMate PHP and Impella.