What is the role of coronary revascularization to recover the contractility of the dysfunctional heart?

Abstract

Coronary artery disease is the predominant aetiology of heart failure and left ventricular dysfunction in industrialized countries. The pathophysiological substrate of hibernating myocardium constitutes the conceptual target of coronary revascularization by coronary artery bypass graft (CABG) or coronary angioplasty or percutaneous coronary intervention (PCI). Studies, mainly observational, conducted in the past have demonstrated a prognostic benefit of CABG on survival. These findings were confirmed by the long-term follow-up of the STICH study in which, however, documentation of inducible ischaemia or myocardial viability was not predictive of a prognostic benefit of CABG. Revascularization via PCI in the recent REVIVED-BCIS2 study did not demonstrate a significant benefit in terms of death or heart failure hospitalization compared with optimal medical therapy. Pending the long-term follow-up of the REVIVED-BCIS2 study, optimized medical therapy, cardiac resynchronization therapy, and the implantable cardioverter defibrillator, where indicated, are the mainstay of treatment in patients with dilated ischaemic cardiomyopathy. The decision for coronary revascularization is made in the individual patient, possibly with a higher bias in patients with angina, three-vessel coronary artery disease, severe left ventricular dysfunction, and cardiac remodelling.

Revascularization and Left Ventricular Dysfunction for ICD Eligibility

“…The so called no-reflow phenomenon is mainly attributed to coronary microvascular dysfunction that includes impaired vasomotor function, extensive microvascular injury with microvascular obstruction, inflammation and hemorrhage following AMI and reperfusion therapy. Furthermore, the ischemic myocardium undergoes structural and functional remodeling due to stunned and hibernating states [ 34 ]. Stunning is referred to the myocardium that is transiently ischemic and displays contractile dysfunction, which ultimately recovers early after restoration of normal resting blood flow.…”

“…Prolonged myocardial hibernation may progress to necrosis, limiting functional recovery after revascularization. Extent of viability is also important, and several studies have shown that at least 25% to 30% of dysfunctional myocardium needs to be viable for improvement in LVEF after revascularization, with the except of extensively remodeled and dilated ventricles which could not recover after revascularization even in the presence of viable areas [ 34 , 35 , 36 ].…”

Treatment Strategies for Chronic Coronary Heart Disease with Left Ventricular Systolic Dysfunction or Preserved Ejection Fraction—A Systematic Review and Meta-Analysis

“…Myocardial revascularization may be considered in patients with left ventricular (LV) systolic dysfunction and appropriate coronary anatomy to improve disease prognosis and alleviate ischemia by addressing the pathophysiological substrate of hibernating myocardium [2,3]. It is noteworthy that patients with LV systolic dysfunction are typically excluded from randomized clinical trials (RCTs) comparing treatment modalities for chronic CHD.…”

“…Consequently, there is a scarcity of publications focused on studying the optimal strategies for this specific patient group. Hence, the majority of guidelines are based on observational studies and expert opinions [3,4].…”