Assessment of Coronary Microvascular Dysfunction in Patients with Systemic Vasculitis

Coronary microvascular dysfunction (CMD) is characterized by impaired coronary blood flow in the absence of obstructive coronary artery disease. CMD primarily involves the microvasculature, leading to myocardial ischemia, angina, and increased cardiovascular risk. Systemic vasculitides (e.g., giant cell arteritis, antineutrophil cytoplasmic antibody-associated vasculitis, and Takayasu arteritis) are a group of autoimmune conditions known to affect the vasculature through inflammation of the blood vessels that have been associated with more prevalent and severe CMD. Although systemic inflammation likely plays a role in the increased risk of cardiovascular events, the underlying pathogenesis is not well understood.

Invasive and non-invasive techniques for assessing coronary microvascular function have been developed to assess for blood flow and coronary flow reserve (CFR), defined as the ratio of the maximum achievable blood flow during stress to the resting blood flow. The purpose of this review is to further explore the relationship between vasculitis and CMD as well as the techniques available for assessing this association.

Studies have shown that CMD is significantly more prevalent in patients with systemic vasculitis compared to the general population. Moreover, in the absence of significant atherosclerotic burden, patients with vasculitis have a lower CFR than controls, indicating more severely impaired coronary vasomotor function. This suggests that systemic inflammation itself is a factor in driving coronary vasomotor abnormalities and CMD development. CMD contributes to cardiovascular morbidity in patients with systemic vasculitis, underscoring the need for early recognition and management. Further studies are needed to determine whether therapies targeting the reduction of systemic inflammation can lead to improved coronary microvascular function and cardiovascular outcomes.