Computed tomography pericoronary adipose tissue density predicts coronary allograft vasculopathy and adverse clinical outcomes after cardiac transplantation

Abstract Aims To assess pericoronary adipose tissue (PCAT) density on coronary computed tomography angiography (CCTA) as a marker of inflammatory disease activity in coronary allograft vasculopathy (CAV). Methods and results PCAT density, lesion volumes, and total vessel volume-to-myocardial mass ratio (V/M) were retrospectively measured in 126 CCTAs from 94 heart transplant patients mean age 49 (SD 14. 5) years, 40% female who underwent imaging between 2010 and 2021; age- and sex-matched controls; and patients with atherosclerosis. PCAT density was higher in transplant patients with CAV n = 40; −73. 0 HU (SD 9. 3) than without CAV n = 86; −77. 9 HU (SD 8. 2), and controls n = 12; −86. 2 HU (SD 5. 4), P 0. 01 for both. Unlike patients with atherosclerotic coronary artery disease (n = 32), CAV lesions were predominantly non-calcified and comprised of mostly fibrous or fibrofatty tissue. V/M was lower in patients with CAV than without 32. 4 mm3/g (SD 9. 7) vs. 41. 4 mm3/g (SD 12. 3), P 0. 0001. PCAT density and V/M improved the ability to predict CAV from area under the receiver operating characteristic curve (AUC) 0. 75–0. 85 when added to donor age and donor hypertension status (P 0. 0001). PCAT density above −66 HU was associated with a greater incidence of all-cause mortality odds ratio OR 18. 0 95% confidence interval (CI) 3. 25–99. 6, P 0. 01 and the composite endpoint of death, CAV progression, acute rejection, and coronary revascularization OR 7. 47 (95% CI 1. 8–31. 6), P = 0. 01 over 5. 3 (SD 2. 1) years. Conclusion Heart transplant patients with CAV have higher PCAT density and lower V/M than those without. Increased PCAT density is associated with adverse clinical outcomes. These CCTA metrics could be useful for the diagnosis and monitoring of CAV severity.