Is there evidence supporting coronary revascularization in patients with left ventricular systolic dysfunction?

The mid- and long-term outcomes of revascularization procedures in patients with chronic left ventricular (LV) systolic dysfunction due to coronary artery disease (CAD) in the presence or absence of heart failure (HF) symptoms are still uncertain. The identification of dysfunctional myocardial segments with residual viability that can improve after revascularization is pivotal for further patient management. Hibernating myocardium (id est (ie), chronically dysfunctional but still viable tissue) can be identified by positron emission tomography (PET) and cardiac magnetic resonance (CMR) and its presence and extent can predict functional recovery after revascularization. Before β-blockers were introduced as routine care for HF, surgical revascularization appeared to improve survival in these patients. Nowadays, novel medical treatments and devices, such as cardiac-resynchronization therapy and implantable cardioverter-defibrillators, have improved the prognosis of HF patients and their use is supported by a number of clinical trials. To adequately address the unresolved issue of the prognostic benefits of coronary revascularization in CAD patients with chronic LV dysfunction on optimal medical therapy with/without devices a randomized trial is warranted. In such a trial the presence of viability will be assessed by either PET or CMR. This is an overview of the pathophysiological mechanisms, as well as of the main clinical studies and meta-analyses that have addressed this issue in the past 4 decades. (author)