CT-derived Epicardial Adipose Tissue Density and Its Association With Systemic Inflammation and Functional Impairment in Heart Failure With Preserved Ejection Fraction: A Prospective Cross-sectional Study From Oman.

Background: Heart failure with preserved ejection fraction (HFpEF) is strongly influenced by cardiometabolic comorbidity and systemic inflammation. Epicardial adipose tissue (EAT) is a biologically active visceral fat depot in direct contact with the myocardium, and CT-derived EAT density (attenuation) may reflect inflammatory adipose remodeling beyond adipose quantity alone. However, the clinical relevance of EAT density in HFpEF remains uncertain. Objectives: To evaluate the association of CT-derived EAT density with systemic inflammatory biomarkers, functional capacity, health status, and echocardiographic indices of HFpEF severity in a prospective cross-sectional cohort. Methods: In a prospective cross-sectional study conducted between January and July 2024 at a tertiary cardiac center in Oman, consecutive patients with HFpEF underwent non-contrast ECG-gated cardiac CT for EAT assessment, laboratory profiling including inflammatory biomarkers, transthoracic echocardiography, 6-min walk testing (6MWT), and Kansas City Cardiomyopathy Questionnaire (KCCQ) evaluation. EAT density was analyzed both as a continuous variable and in exploratory categorical analyses. Associations were examined using correlation analyses and multivariable linear regression with adjustment for clinically relevant covariates. Results: Among 110 participants (mean age 65 ± 10 years; 53% women), mean EAT density was -85 ± 10 HU. Higher EAT density was associated with higher hs-CRP (r = 0.50, p < 0.001), IL-6 (r = 0.48, p < 0.001), and TNF-α (r = 0.46, p < 0.001). Higher EAT density was associated with higher hs-CRP (r = 0.50, p < 0.001), IL-6 (r = 0.48, p < 0.001), and TNF-α (r = 0.46, p < 0.001). In exploratory adjusted analyses incorporating natriuretic peptide burden, renal function, and other clinically relevant covariates, these associations were attenuated but remained directionally consistent. Patients with higher EAT density showed lower 6MWT distance (320 ± 75 vs 400 ± 70 m, p < 0.001) and lower KCCQ overall score (60 ± 12 vs 75 ± 10, p < 0.001). These findings should be interpreted cautiously pending fuller adjustment for HF severity, renal function, and treatment-related covariates. Conclusions: In this HFpEF cohort, higher CT-derived EAT density was associated with greater inflammatory burden and worse functional status. These findings suggest that EAT density may serve as an imaging correlate of the cardiometabolic-inflammatory HFpEF phenotype, although further validation is required before broader clinical application.