Mechanical Circulatory Support on Coronary Artery Bypass Grafting for Advanced Ischemic Cardiomyopathy: State of the Art.

Ischemic cardiomyopathy is defined as coronary artery disease accompanied by left ventricular dysfunction with an ejection fraction equal to or less than 40%. The substrate of ischemic cardiomyopathy is heterogeneous, characterized by the coexistence of normal, stunned, hibernating, and scarred myocardium within the same myocardial region. Altogether, these components may represent different phases of a single pathological process. It is well-established that the assessment of isolated myocardial viability and ischemia alone has failed to reliably guide the indication for coronary artery bypass grafting (CABG). CABG in patients with low ejection fraction carries a significant risk of perioperative mortality and morbidity, largely related to the development of postcardiotomy shock. Preoperative optimization with pharmacologic or mechanical circulatory support (MCS) is often essential; the decision requires integrating multiple complex factors, including clinical presentation, response to optimization therapy, myocardial viability, the presence of hibernating or scarred myocardium, left ventricular end-systolic volume index, coronary angiography findings, hemodynamic assessment, and the Pulmonary Arterial Pressure Index score. A preoperative evaluation that incorporates anatomical, morphological, functional, and hemodynamic domains enables more precise selection and timing of MCS. Preemptive left ventricular unloading mitigates the physiological impact of cardiopulmonary bypass, preserves end-organ perfusion, and reduces the need for high-dose vasopressors. However, the risk-benefit ratio remains uncertain and may be associated with serious complications. Careful judgment regarding the indications for MCS has the potential to enhance the safety of CABG in high-risk patients, but robust, long-term, prospective studies are needed to determine its true impact on clinical outcomes. In this review, we will examine the indications and criteria for the use of MCS in patients with advanced ischemic cardiomyopathy, as well as the various devices available for preoperative or intraoperative support, including technical considerations, advantages and disadvantages, and associated complications.