Abstract 12029: The Impact of the Myocardial Bridge on Coronary Functional Test in Patients With Ischemia With Non-Obstructive Coronary Arteries

Abstract

Introduction: The possibility of myocardial bridge (MB) causing chest pain has been widely reported; however, the effect of MBs on coronary microvessels has not been thoroughly investigated. Hypothesis: Thus, this study evaluated the effects of MB on epicardial coronary artery and coronary microvascular function during coronary angiography (CAG) and coronary function tests (CFT) in patients with ischemia with non-obstructive coronary arteries (INOCA). Methods: This study included 57 patients with INOCA who underwent CAG and CFT to evaluate chest pain. In CFT, acetylcholine was first administered intracoronarily in a stepwise manner, followed by chest symptoms, electrocardiographic changes [Editor1] and CAG. Positive coronary spasm was defined as coronary vasoconstriction of >90% on CAG accompanied by chest symptoms or electrocardiographic ST-T changes. After nitroglycerin administration, CAG was performed to assess MB, which is defined as the systolic narrowing of the coronary artery diameter by >20% compared to that in diastole. Coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) were subsequently obtained by transvenous adenosine triphosphate infusion using a pressure wire. Coronary microvascular vasodilatory dysfunction (CMD) was defined as CFR of <2.0 or IMR of ≥25 units. Results: Of the 57 patients, 13 (23%) had MB. The CAG and coronary CFT results in the MB (+) and MB (–) groups are shown below. Conclusions: These findings suggest that MB predisposes to coronary spasms in patients with INOCA. Conversely, MBs may have a limited effect on microvessels, particularly in such patients.