Frequency of Screening for Cardiac Allograft Vasculopathy: Warranty Period of Initial Low Risk Positron Emission Tomography.

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 program. 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 program (within 6-18 months of initial scan). PET CAV results were graded according to a published and externally validated diagnostic criteria 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 (IQR 363 - 433). Initial PET CAV grade was the most significant patient characteristic associated with progression of CAV, with 17% of patients with PET CAV 1 progressing to CAV 2/3 compared to 1.6% with PET CAV 0 (OR 12.4, 95%CI 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 multicenter registries.