Feasibility of Non-Invasive Screening for Coronary Allograft Vasculopathy with Positron Emission Tomography Derived Myocardial Blood Flow Assessment

Abstract

Background Recent studies have shown promising data supporting the use of positron emission tomography (PET) in place of the current invasive gold standard, coronary angiography to screen for coronary allograft vasculopathy (CAV). Hypothesis We hypothesize that PET can functionally assess flow using myocardial blood flow (MBF) which correlates with CAV and can portend poor outcomes. Methods We retrospectively identified all heart transplant recipients who had regadenoson rubidium-82 PET rest-stress tests and coronary angiography at our institution between November 2012 and March 2019. CAV grade was based on ISHLT criteria according to Figure 1 which is adapted from researchers at Brigham and Women's Hospital. A cutoff of MBF Results We collected data from 31 patients with 44 PET studies. Of this population, 28 patients had coronary angiography performed which resulted in 37 total PET studies for comparison. Of the total collection of PET studies, 36% had CAV 0 (n=16), 36% had CAV 1 (n=16), and 28% had CAV 2-3 (n=12). When analyzing the subset who had both PET and angiography (n=31), of those with grade 0 CAV on PET, all patients also had no angiographic CAV (n=13). Of those with PET grade 2 or 3 CAV, 2 patients had no angiographic CAV and 6 patients had corresponding moderate-severe CAV angiographically. Conclusion PET appears to be a good screening modality for CAV, as all of those with severe CAV angiographically had at least grade 1 CAV on PET. PET should be strongly considered as the primary method of CAV screening to avoid the risks of invasive angiography in a particularly delicate population of patients.