Ischemic cardiomyopathy, the term used to describe systolic dysfunction due to chronic myocardial ischemia from ischemic heart disease, is the most common form of heart failure. To adapt to this ischemic environment, myocardium is known to undergo downregulation that may revert after adequate perfusion is re-established, a phenomenon known as myocardium hibernation. This phenomenon has been a background for the main concept of management for ischemic cardiomyopathy via revascularization. Indeed, the recent 10-year follow-up reports from STICH trial demonstrated improved long-term clinical outcomes after coronary bypass graft surgery than optimal medical therapy (OMT) in patients with ischemic cardiomyopathy.
Percutaneous coronary intervention (PCI) is another intervention that is commonly used to revascularize significant coronary stenosis. Despite common belief that revascularization by PCI would improve perfusion to ischemic myocardium and improve clinical outcomes, several clinical trials have failed to show beneficial impact of PCI over OMT in stable ischemic heart disease other than symptomatic improvement. Recently published REVIVED trial compared effect of PCI and OMT in ischemic cardiomyopathy patients with left ventricular ejection fraction \< 35% and demonstrable viable myocardial segments, and found no significant difference in clinical outcomes of both groups.
However, whether PCI optimized by additional information can make a difference in this setting remains unanswered. It is known that intravascular imaging and coronary physiologic testing using intravascular ultrasound (IVUS), optical coherence tomography (OCT) or fractional flow reserve (FFR) result in better outcomes compared to conventional angiography alone. IVUS provides anatomical information regarding the lumen, plaque, and plaque characteristics, and can optimize stent placement minimizing stent-related problems and lead to better outcomes. On the other hand, FFR provides information on amount of ischemia which the stenosis in question is causing, and also improves the quality of PCI which has been demonstrated by multiple previous trials. Unfortunately, proportion of IVUS and FFR use is not disclosed in REVIVED trial, and it is possible there is a room for improvement if the PCI is further guided by these adjunctive diagnostic procedures in regard to the clinical outcomes.
In this regard, it is our hypothesis that PCI guided and optimized by intravascular imaging and FFR-guided strategy would bring additional benefit that may result in significant difference of prognosis for ischemic cardiomyopathy compared to OMT alone. Randomized controlled trial to test this hypothesis would provide valuable evidence to guide treatment strategy for ischemic cardiomyopathy. Therefore, RESTORE-PCI trial has been designed to compare clinical outcomes after state-of-the-art PCI or OMT for ischemic cardiomyopathy.
The aim of the study is to compare clinical outcomes between revascularization versus medical treatment alone in patients with ischemic cardiomyopathy and left ventricular dysfunction. Primary hypothesis is that revascularization guided by invasive physiologic indexes and optimized by intravascular imaging device plus optimal medical treatment (OMT) would reduce risk of primary composite end point (major adverse cardiac events \[MACE\], a composite of death, myocardial infarction (MI), admission for heart failure, or advanced heart failure requiring LVAD or transplantation) than OMT alone in patients with ischemic cardiomyopathy.
