SHIELD II Clinical Investigation

Inclusion Criteria: * At least 18 years of age * Subject is undergoing elective or urgent high-risk PCI procedure and is hemodynamically stable * Subject is indicated for a revascularization of at least one de novo or restenotic lesion in a native coronary vessel or bypass graft * A heart team, including a cardiac surgeon, has determined high risk PCI is an acceptable therapeutic option * Subject must provide written informed consent prior to any clinical investigation related procedure Imaging Inclusion Criteria: • The presence of complex coronary artery disease (CAD) makes hemodynamic instability resulting from repeat episodes of reversible myocardial ischemia during PCI likely. Complex CAD is defined as an ejection fraction of \<50% by echocardiographic assessment AND at least one of the following: * intervention of the last patent coronary conduit, OR * intervention of an unprotected left main artery, OR * intervention on patient presenting with triple vessel disease defined as at least one significant stenosis (at least 50% diameter stenosis on visual assessment) in all three major epicardial territories Exclusion Criteria: * Emergency PCI * Any prior coronary revascularization within the last 6 months * Any MI with elevated cardiac biomarker (creatinine kinase-MB (CK-MB) or troponin \>1X upper limit of normal (ULN)) and no evidence of at least 1 consecutive CK-MB or troponin value trending downward from previous value (at least 4 hours apart) OR ST Elevation MI (STEMI) within 72 hours prior to the index procedure regardless of the level of cardiac biomarker * Cardiac arrest within 24 hours of procedure requiring cardiopulmonary resuscitation (CPR) or defibrillation * Any use of a mechanical circulatory support device within 14 days prior to the index procedure (Note: Subjects must be hemodynamically stable without any hemodynamic support to be eligible for this clinical investigation.) * Hemodynamic support with a mechanical circulatory support device (e.g.,the HeartMate PHP, Impella, intra-aortic balloon pump (IABP), or extracorporeal membrane oxygenation (ECMO)), post-PCI is anticipated * Any condition that requires discontinuation of antiplatelet and/or anticoagulant therapy within 90 days following the index procedure (e.g., planned noncardiac surgery) * Any use of vasopressors or inotropes within 24 hours prior to the index procedure * Staged PCI is planned within 90 days following device removal * Cardiogenic shock (SBP \<90 mmHg for \>1 hour with either cool clammy skin OR oliguria OR altered sensorium AND cardiac index \<2.2 L/min/m\^2) * History of aortic valve replacement or repair * Severe peripheral vascular disease that will preclude the use of a 14F access sheath, which is required for the insertion of the HeartMate PHP catheter (If the investigator is unsure of the presence or severity of the peripheral vascular diseases for study device access, an appropriate imaging assessment (e.g., duplex ultrasound, angiogram or computerized tomography) should be performed to verify the access before randomization.) * Known abnormalities of the aorta that would preclude surgery, including aneurysms and significant tortuosity or calcifications * Subject is on hemodialysis * Liver dysfunction with elevation of liver enzymes and bilirubin levels to ≥ 3X ULN or Internationalized Normalized Ratio (INR) ≥1.6 or lactate dehydrogenase (LDH) \> 2.5X ULN * Abnormal coagulation parameters (platelet count ≤75000/mm\^3 or INR ≥1.6 or fibrinogen ≤1.5 g/l) * Active systemic infection requiring treatment with antibiotics * Subject had active COVID-19 symptoms and/or a positive test result within the prior 2 months * Stroke or transient ischemic attack (TIA) within 6 months of procedure * Any allergy or intolerance to ionic and nonionic contrast media, anticoagulants (including heparin), or antiplatelet therapy drugs that cannot be adequately premedicated * Subject is pregnant (For a female subject of childbearing potential, a pregnancy test must be performed within 14 days (≤14 days) prior to the index procedure per site standard test) * Participation in another clinical study of an investigational drug or device that has not met its primary endpoint * Presence of other anatomic or comorbid conditions, or other medical, social, or psychological conditions that, in the investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with followup requirements, or impact the scientific soundness of the clinical investigation results * Life expectancy \<1 year Imaging Exclusion Criteria: * Mural thrombus in the left ventricle * Documented presence of aortic stenosis (orifice area of 1.5 cm\^2 or less) * Moderate to severe aortic insufficiency by echocardiographic assessment