The crux of maximum hyperemia: the last remaining barrier for routine use of fractional flow reserve

In the decision-making process of revascularization of coronary artery stenoses by percutaneous coronary intervention (PCI) or coronary artery bypass graft surgery (CABG), the presence and extent of reversible ischemia associated with such particular stenoses is of paramount importance (1, 2, 3). A stenosis associated with reversible ischemia (also called functionally significant or hemodynamically significant stenosis) causes symptoms of angina pectoris and has a negative influence on outcome (1, 2). Therefore, the general feeling is that such lesions should be revascularized if technically feasible. On the contrary, functionally nonsignificant stenoses do not cause symptoms by definition and have an excellent outcome with medical therapy (3, 4, 5). Therefore, revascularization of such lesions is generally not indicated.