The PROTECT-EU Study

Inclusion Criteria: Patients with non-emergent chronic or acute coronary syndromes (the former refused from surgical revascularization) with reduced LVEF (left ventricular ejection fraction)(\<=40%) and indication for high-risk PCI AND Intended high-risk PCI defined as having at least one of the following criteria: * Unprotected left main distal disease involving bifurcation or trifurcation or left main equivalent * Diffuse degenerated (\>5 mm) saphenous vein grafts involving the proximal or distal anastomosis or in-stent restenosis * LAD (left anterior descending) long lesions (\>48 mm) involving both septal and diagonal branches requiring multiple and overlapping stents * Diffuse and severely calcified lesions (see protocol definition) with need for debulking devices (directional, rotational, orbital, and laser) * Last patent conduit * Complex CTO (chronic total occlusion) (J-CTO score 3) or CTO in patients with MVD (Coronary Microvascular Disease) * MV-PCI (Multivessel Percutaneous Coronary Intervention) in patient with a Syntax score\>32 undergoing planned complete revascularization (see protocol definition of severe stenosis) * (only in ACS Acute Coronary Syndrome patients) Giant thrombus (length ≥3x vessel diameter) in the context of MVD or Syntax score \>32. Exclusion Criteria: * Classic CS Coronary Sinus (relative hypotension as SBP \< 90 mmHg, or MAP \<60 mmHg or \>30 mmHg drop from baseline and drugs/device used to maintain blood pressure above these targets and/or symptoms/signs of hypoperfusion as cardiac index \<2.2, lactate ≥ 2mmol/L (24). * Cardiac arrest * Patients admitted for ACS due to ST-elevation MI (ST Elevation Myocardial Infarction) * Contraindication to Impella positioning: mural thrombus in the left ventricle; presence of a mechanical aortic valve; severe aortic stenosis or valvular regurgitation; severe peripheral arterial disease precluding placement of the Impella System; haematological disorder causing fragility of the blood cells or hemolysis; hypertrophic obstructive cardiomyopathy (HOCM); aneurysm or severe anomaly of the ascending aorta and/or aortic arch; significant right heart failure; presence of an atrial or ventricular sepal defect (including post-infarct VSD Ventricular Septal Defect); left ventricular rupture; cardiac tamponade; recent TIA or stroke (within 1 month); contraindication to anticoagulation * Age \< 18 or \> 80 years old * Inability to understand and sign informed consent * Serious known concomitant disease with a life expectancy of less than one year * Prior thrombolytic therapy during the index event (within 72 h of presentation) * Severe renal impairment Renal insufficiency (GFR Glomerular Filtration Rate \<30 ml/min) * Patients on oral anticoagulation therapy (including novel oral anticoagulant such as dabigatran, rivaroxaban, apixaban and edoxaban) at the time of PCI * Suspected or known pregnancy * Suspected active infection * Current participation in an investigational study using a drug or device.