Inclusion Criteria:  Extensive coronary disease defined by a British Cardiovascular Intervention Society (BCIS) Jeopardy Score ≥ 8* Severe left ventricular systolic dysfunction defined as a LVEF ≤ 35% (or ≤ 45% in the presence of severe mitral regurgitation)#  Complex PCI defined by the presence of at least one of the following criteria:  Unprotected left main intervention in the presence of  an occluded dominant right coronary artery, or a left dominant circulation, or disease involving the entire bifurcation (Medina1,1,1 or 0,1,1)  Intended calcium modification (by rotational atherectomy, lithotripsy or laser) o inmultiplevesselsor  in the left main stem, or in a final patent conduit, or where the anatomic SYNTAX score is ≥32  Target vessel is a chronic total occlusion with planned retrograde approach * In general, patients who do not have bypass grafts will be eligible if the patient has at least proximal left anterior descending (LAD) disease or at least proximal 2 vessel disease. For patients with patent bypass grafts, or in cases where the extent of coronary artery disease (CAD) is uncertain, the BCIS-1 JS should be calculated. The maximum possible JS score is 12. N.B. The JS should be based on all coronary disease, not just the vessel subtending viable myocardium.  Biplane / 3D echocardiography, or cardiac MRI can be used to assess the qualifying LVEF.  Exclusion Criteria:  Cardiogenic shock or acute STEMI at randomisation Contraindication to pLVAD insertion Inability to give informed consent Previously enrolled in CHIP or current enrolment in another interventional study that may affect CHIP outcomes