Significant improvements in revascularization techniques and adjunctive therapy have resulted in improved outcomes in patients with coronary artery disease. However, a sub-population of these patients continues to have disabling, chronic refractory angina. Refractory angina has been defined as three or more months of angina due to demonstrated coronary insufficiency that persists despite optimal medical therapy [ ]. No-option refractory angina describes patients no longer amenable to further revascularization by either percutaneous or surgical revascularization [ ]. Anatomic reasons which may preclude revascularization for refractory angina include diffuse, distal or side-branch disease, recurrent restenosis, degenerated vein grafts, poor distal target lesions, lack of conduits or other patient-related factors including extra-cardiac disease and frailty [ ]. A smaller sub-population of no-option refractory angina patients have Canadian Cardiovascular Society (CCS) functional Class III or IV angina resulting in severe limitation in their ability to perform activities of daily living.