Abstract 13592: Combined Analysis of Epicardial and Microcirculatory Conductance in Patients With Intermediate Coronary Stenoses

Aim: Although atherosclerosis also affects microvascular function, its prevalence in vessels with intermediate stenoses remains largely unknown. In cases with normal fractional flow reserve (FFR), revascularization is not required either because coronary resistance is normal or because concomitant microcirculatory disease exists. However, the latter may be a cause of anginal symptoms or myocardial ischemia. We investigated the prevalence of microcirculatory dysfunction fractional during the performance of fractional flow reserve (FFR) in an unselected population of patients with coronary artery disease undergoing invasive assessment. Methods and results: Intracoronary thermodilution indices of coronary flow reserve (CFR) and microcirculatory resistance (IMR) were measured in 41 arteries (32 patients) presenting an intermediate coronary artery stenosis assessed with FFR. Cut off values were CFR = 2.00, IMR = 29 and FFR = 0.80 were used. A four-quadrant distribution of FFR / CFR values was used. Overall, 25 (61%) vessels with stenoses with associated FFR ≥ 0.80 were found. Of these, 48% (n=11) presented abnormal CFR. High microcirculatory resistance (IMR ≥ 29) was more frequent in vessels with stenosis with FFR≥ 0.80 (56%, n=14) than with FFR Conclusions: A significant number of patients with intermediate stenoses and normal FFR values present abnormal microcirculatory resistance (IMR ≥ 29). This fact must be taken into account to explain the discrepancies between hemodynamic relevance assessed with FFR and other manifestations of coronary artery disease that may result from microcirculatory disease.