Impact of epicardial fat on coronary vascular function, cardiac morphology, and cardiac function in women with suspected INOCA.

Aims: Epicardial fat is a metabolically active adipose tissue depot situated between the myocardium and visceral pericardium that covers ∼80% of the heart surface. While epicardial fat has been associated with the development of atherosclerotic coronary artery disease, less is known about the relationship between epicardial fat and coronary vascular function. Moreover, the relations between excess epicardial fat and cardiac morphology and function remain incompletely understood.

Methods and results: To address these knowledge gaps, we retrospectively analysed data from 294 individuals from our database of women with suspected ischaemia with no obstructive coronary disease (INOCA) who underwent both invasive coronary function testing and cardiac magnetic resonance imaging. Epicardial fat area, biventricular morphology, and function, as well as left atrial function, were assessed from cine images, per established protocols. The major novel findings were two-fold: first, epicardial fat area was not associated with coronary vascular dysfunction. Secondly, epicardial fat was associated with increased left ventricular concentricity (β = 0.15, P = 0.01), increased septal thickness (β = 0.17, P = 0.002), and reduced left atrial conduit fraction (β = -0.15, P = 0.02), even after accounting for age, BMI, and history of hypertension.

Conclusion: Taken together, these data do not support a measurable relationship between epicardial fat and coronary vascular dysfunction but do suggest that epicardial fat may be related to concentric remodelling and diastolic dysfunction in women with suspected INOCA. Prospective studies are needed to elucidate the long-term impact of epicardial fat in this patient population.