Abstract 14662: What Factors Contribute to the Presence of Coronary Microvascular Dysfunction in Patients With Non-Obstructive Coronary Artery Disease?

Introduction: In recent years, there has been growing interest in coronary microvascular dysfunction (CMD). Several risk factors have been discussed as causes of CMD, but there are still many unknowns.

Hypothesis: In this study, we evaluated clinical risk factors for CMD in patients with chest pain with non-obstructive coronary artery disease (INOCA).

Methods: Sixty-two patients who were able to undergo comprehensive coronary angiography at the time of chest pain screening were included in the study. Patients with a history of heart failure were excluded. Comprehensive angiography excluded patients with organic coronary artery stenosis (%stenosis>50%) and was performed with the spasm provocation test using acetylcholine (ACh) to induce coronary spasm and with a pressure wire to evaluate CMD. Positive coronary spasm was defined as the presence of usual chest pain or electrocardiographic changes and >90% coronary artery constriction on angiograms in response to ACh provocation. In addition, a coronary spasm within one section of the American Heart Association’s classification was defined as a focal spasm. CMD was defined as the presence of coronary flow reserve (CFR) < 2.0 or an index of microcirculatory resistance (IMR) ≥ 25 obtained from a pressure wire. The clinical background leading to CMD was investigated and evaluated by logistic analysis.

Results: Of 62 patients with INOCA, 26 (42%) had CMD. The results are shown in the table.

Conclusions: These results suggested that factors contributing to CMD in INOCA patients were diverse: women, smoking, focal spasm, and elevated NTproBNP level. It is necessary to identify the cause of CMD before treatment in such patients.