Invasive coronary flow reserve measurement

CFR was measured using a standardized protocol.12 A Doppler guidewire was placed in the proximal left anterior descending (LAD), and assessed coronary flow, with intracoronary adenosine (18 and 36 μg) used to achieve hyperaemia. CFR was derived from the ratio of the average peak velocity of blood flow at maximal hyperaemia and average peak velocity at rest as previously described. We have previously shown that this ratio closely approximates volumetric CFR in similar women enrolled in WISE.13 Graded doses of intracoronary acetylcholine (0.182 and 18.2 μg/mL) were infused to determine % epicardial coronary artery diameter change (ΔAch) and % coronary blood flow change (ΔCBF) in response to acetylcholine, as previously described.12^,14