Abstract 12018: Coronary Microvascular Dilatory Dysfunction According to the Types of Coronary Functional Abnormalitiescoronarymicrovascular Dilatory Dysfunction According to the Types of Coronary Functional Abnormalities

Abstract

Introduction: Recently, there has been an increasing interest in coronary functional abnormalities (CFA), which include epicardial coronary spasm (ECS), microvascular spasm (MVS) and microvascular vasodilatory dysfunction (MVD). However, the frequency of MVD according to the types of CFA remains unclear. Hypothesis: Thus, this study aimed to investigate the frequency of MVD according to the types of CFA in patients with ischemia with non-obstructive coronary arteries (INOCA). Methods: This study included 63 patients with INOCA who underwent coronary angiography (CAG) and coronary function tests (CFT) to evaluate chest pain. In CFT, acetylcholine was first administered intracoronarily in a stepwise manner, followed by chest symptoms, electrocardiographic ST-T changes and CAG. ECS was defined as coronary vasoconstriction of >90% on CAG accompanied by chest symptoms or electrocardiographic ST-T changes. Additionally, a focal spasm was defined as a transient vessel narrowing of >90% within the borders of one isolated coronary segment (as defined by the American Heart Association), and a diffuse spasm was defined as a 90% diffuse vasoconstriction in ≥2 adjacent coronary segments of the coronary artery. Moreover, MVS was defined as the presence of both chest symptoms and ST-T changes with non-significant coronary vasoconstriction (<90%) on CAG. After nitroglycerin administration, coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) were subsequently obtained by transvenous adenosine triphosphate infusion using a pressure wire. MVD was defined as CFR of <2.0 or IMR of ≥25 units. Results: CAG and CFT were performed on 91 coronary arteries in 63 patients with INOCA, the results of which are shown below. Conclusions: These findings suggest that the frequency of MVD differs according to the types of CFA. Properly evaluating the MVD and reflecting this in the therapeutic strategy in patients with INOCA is desirable in clinical settings.