Will Resting Full-Cycle Ratio Substitute Fractional Flow Reserve

Physiological assessment of coronary artery stenosis added an element of certainty of benefit to the patient undergoing revascularization. Fractional flow reserve (FFR) was the gold standard, with good reproducibility, correlation with noninvasive inducible ischemia testing and, most importantly, clinical benefit. Increased usage also brought into focus some limitations with respect to achieving hyperemia, assessment of sequential stenoses, drift, multivessel disease, chronic total occlusion, fidelity and accuracy of measurement and, in some cases, cost of adenosine. This set the background for nonhyperemic testing which eliminates the need for drug administration and simplifies procedure vastly.