Frequency of screening for cardiac allograft vasculopathy: warranty period of initial low risk positron emission tomography

Abstract

Abstract Aims The short-term risk of moderate–severe cardiac allograft vasculopathy (CAV) after a low-risk positron emission tomography/computed tomography (PET/CT) is unknown, and therefore, there is no guidance on how frequently to perform screening. The aim of this study was to assess the rate of progression to moderate–severe CAV as part of an annual screening programme. Methods and results Patients with no history of CAV 2/3 and a low-risk result on initial screening PET/CT (CAV 0/1) were enrolled in the study. The primary outcome was the progression to CAV 2/3 as part of an annual screening programme (within 6–18 months of initial scan). PET CAV results were graded according to a published and externally validated diagnostic criterion for CAV. Over the study period, 231 patients underwent an initial PET/CT and had a subsequent evaluation for CAV. In this cohort, 4.3% of patients progressed to CAV 2/3 at a median of 374 days (interquartile range 363–433). Initial PET CAV grade was the most significant patient characteristic associated with the progression of CAV, with 17% of patients with PET CAV 1 progressing to CAV 2/3 compared with 1.6% with PET CAV 0 (odds ratio 12.4, 95% confidence interval 3.06–50.3). Conclusion The rate of progression to moderate–severe CAV at 1 year after the lowest-risk PET/CT is low, but approximately 1/6 patients with PET CAV 1 progress to CAV 2/3. Annual screening with PET/CT for select patients with PET CAV 0 may not be warranted. The optimal screening interval awaits confirmation of our findings in multi-centre registries.