Pericardial adipose tissue (PAT) in obesity has been shown to be an independent risk factor for coronary heart disease but the underlying mechanism remains incompletely understood. We aimed to elucidate the interrelationship between PAT expansion and the adipose tissue vascularization. PAT samples were collected from patients with coronary heart disease (19 patients; age: 48-79; BMI: 22.29-41.09). Tissue samples were stained using H&E and the number and size of adipocytes was quantified using unbiased techniques via AdipoCount and ImageJ. PAT samples, cut 40 μm thick, were immunolabelled using DyLight 594 fluorescent tomato-lectin dye followed by quantification of the tissue vasculature using an unbiased, automatic 3D reconstruction (Vesselucida360). Angiogenesis was quantified using an ex vivo angiogenic assay whereby pericardial vessels were isolated, cut, and embedded in a collagen matrix sustained with growth factors; number of sprouts were used as a measure of angiogenic potential and were further analyzed for length and branching in ImageJ. Patients exhibited an increased adipocyte size as BMI increased with measures of vascularization, such as number of branching nodes and total vessel length, showed a negative correlation to increasing BMI. Vessel volume and vessel surface area showed no correlation to patient BMI. Angiogenic potential, measured by the number of vessel sprouts, sprouting length, branching length, and branching interval, showed a significant association with increasing BMI. Our data show that while adipocyte size increases with an increasing BMI, the PAT vascularization had a negative correlation to increasing BMI. These results suggest that the vasculature is insuffcient to supply the increasing PAT demand, leading to impaired perfusion and eventual adipose tissue dysfunction. However, there was a significant increase in angiogenic potential that shows that when provided with growth factors, these vessels have the ability to increase their angiogenic potential, yet in vivo the vascular angiogenic response may be hindered, which needs to be further studied. T32 HL155011 (KAF) F31 NS132564 (KAF). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.