Origin of angina pectoris in patients with high-grade single-vessel coronary artery stenosis undergoing percutaneous transluminal coronary angioplasty.

This study shows that in patients with subtotal (95% to 99%) coronary artery stenosis, the presence of myocardial ischemia is dictated primarily by the presence and degree of coronary collateral flow, with anterograde flow participating little, if at all, in the origin of myocardial ischemia and angina pectoris. Conversely, in patients with severe but not subtotal coronary artery stenosis (70% to 94%), both reduced anterograde flow and coronary collateralization contribute to the evolution of myocardial ischemia and angina pectoris.