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

Abstract Background Coronary allograft vasculopathy (CAV) is a common cause of heart transplant failure. Coronary Computed Tomography Angiography (CCTA) is used to assess for luminal stenoses in patients with suspected CAV, but additional non-invasive markers are needed to detect early disease and guide the use of treatments that can prevent or slow CAV progression. Purpose We tested the hypotheses that: 1) coronary artery inflammation assessed by pericoronary adipose tissue (PCAT) density and/or total vessel volume-to-myocardial mass ratio (V/M) measured by CCTA could improve the ability to detect CAV in heart transplant patients; and 2) these semi-automated quantitative CCTA metrics would be associated with adverse clinical outcomes. Methods In this retrospective observational cohort study, PCAT density, V/M, and lesion composition were measured in consecutive CCTAs from patients who underwent heart transplantation at a single site between 2010 to 2021. These parameters were incorporated into predictive models for CAV as defined by International Society for Heart & Lung Transplant criteria, and evaluated against long-term clinical outcomes. Results A total of 126 CCTAs were analysed from 94 patients after heart transplant (mean age 49 [SD 14.5] years, 40% female) without CAV (n=86) and with CAV (n=40). PCAT density was higher in transplant patients with CAV (-73.0 HU [SD 9.26]) than without CAV (-77.9 HU [SD 8.23]), and age and sex-matched controls (n=12; -86.19 HU, [SD 5.38]), p