Cardiogenic shock, a state of physiological shock due to decreased heart function after a heart attack, occurs in only 7% to 10% of patients who have a heart attack; however, cardiogenic shock is the most common cause of death shortly after a heart attack. Many patients who have had a heart attack require treatment of the arteries that supply blood to the heart and each year in the United States, approximately 658,000 patients undergo percutaneous coronary intervention (PCI) procedures to treat these arteries. Guidelines prepared jointly by the American College of Cardiology and 2 other professional organizations state that, for PCI performed during cardiogenic shock, heart function can be partially stabilized with devices that help the heart pump blood, such as an intra-aortic balloon counterpulsation pump (IABP). In several studies of PCI during cardiogenic shock, the patient survival rate has been only 20% despite use of an IABP. Moreover, IABP use has been associated with major complications in 4% to 14% of patients. Consequently, other types of ventricular assist devices have been developed in an attempt to improve patient survival and reduce the incidence of serious complications.