Javier Escaned1, MD, PhD; Tsunekazu Kakuta2, MD, PhD
1. Hospital Clinico San Carlos IDISSC, Universidad Complutense de Madrid, Madrid, Spain; 2. Division of Cardiovascular Medicine, Tsuchiura Kyodo General Hospital, Ibaraki, Japan
“As is our confidence, so is our capacity” – William Hazlitt
Coronary flow reserve (CFR) was originally formulated as a functional index to explore the functional relevance of coronary stenoses1. In a communicative way, the rationale behind CFR could be expressed as follows: “If you want to know if a stenosis is severe, go and ask the microcirculation”. A clever approach - coronary stenosis first causes subtended arterioles to vasodilate to maintain resting flow and, eventually, also causes a decrease in maximal hyperaemic flow. All this trims the range of microvascular vasodilation, indirectly ...