Cardiac allograft vasculopathy (CAV) causes impaired blood flow in both epicardial vessels and microvasculature and remains a leading cause of posttransplant morbidity and mortality. This study examined the prognostic value and outcomes of CAV, assessed by 13N-ammonia PET/CT myocardial perfusion imaging in heart transplant recipients. Methods: PET/CT and invasive coronary angiography (ICA) were graded using validated scales. CAV progression was assessed using intrapatient sequences: baseline ICA, interval PET/CT with myocardial blood flow reserve, and subsequent ICA. Intervals between ICAs of 600, 900, and 1200 d were included, and for each, the negative predictive value (NPV) of CAV development was assessed. Results: In total, 344 heart transplant recipients underwent PET/CT for CAV assessment with a median follow-up of 4.8 y. PET CAV grade 0/1 had an NPV of 0.93, 0.95, and 0.95 at each respective time point for developing an International Society for Heart and Lung Transplantation CAV 2/3 on subsequent ICA. Compared with PET CAV 0, PET CAV 2/3 was associated with a 2.9-fold increased risk of all-cause mortality (hazard ratio, 2.86; 95% CI, 1.36–6.00; P = 0.006). PET CAV 1 had a numerically increased risk (hazard ratio, 2.03; 95% CI, 0.99–4.15; P = 0.054). In a sensitivity analysis of 135 patients with stable International Society for Heart and Lung Transplantation CAV over successive ICA, PET CAV 2/3 remained associated with increased risk of death or retransplantation (hazard ratio, 3.20; 95% CI, 1.18–8.69; P = 0.03). Conclusion: Noninvasive CAV assessment by PET/CT and myocardial blood flow reserve provides prognostic information and robust NPVs for development of moderate to severe CAV over intervals up to 4 y. These data suggest that, for certain patients, intervals between invasive screenings may be extended.

PET/CT with Myocardial Blood Flow Assessment Is Prognostic of Cardiac Allograft Vasculopathy Progression and Clinical Outcomes