Aortic Stiffness Is Associated with Coronary Microvascular Dysfunction in Patients with Non-obstructive Coronary Artery Disease

OBJECTIVE: Associations between aortic stiffness and cardiovascular disease events are mediated in part by pathways that include coronary microvascular dysfunction (CMD) and remodeling. However, the relationship between aortic stiffness and CMD remains unclear. The present study aimed to determine whether aortic stiffness causes CMD as evaluated by the hyperemic microvascular resistance index (hMVRI) in patients with non-obstructive coronary artery disease (CAD). METHODS: The intracoronary physiological variables in 209 coronary arteries were evaluated in 121 patients with non-obstructive CAD (fractional flow reserve >0.80) or reference vessels. The cardio-ankle vascular index (CAVI) as a measure of aortic stiffness and atherosclerotic risk factors were also measured. RESULTS: Univariate analyses showed that hMVRI correlated with age (β=0.24, p=0.007), eicosapentaenoic acid (EPA; β=-0.18, p=0.048), EPA/arachidonic acid (AA) (EPA/AA) ratio (β=-0.22, p=0.014) and CAVI (β=0.30, p=0.001). A multivariate regression analysis identified CAVI (β=0.25, p=0.007) and EPA/AA ratio (β=-0.26, SE=0.211, p=0.003) as independent determinants of hMVRI. CONCLUSION: Aortic stiffness may cause CMD in patients with non-obstructive CAD via increased coronary microvascular resistance. Aortic stiffness is associated with CMD which is evaluated as hyperemic microvascular resistance in patients with non-obstructive CAD.