Abstract 4147215: Cardiac Magnetic Resonance Imaging vs Positron Emission Tomography in the Assessment of Viability in Ischemic Cardiomyopathy. The Alternative Imaging Modalities in Heart Failure (AIM-HF) Clinical Trial

Background: Patients with ischemic heart failure (IHF) often undergo myocardial viability assessment to help determine the appropriate treatment strategy, whether revascularization or medical therapy. However, there is a lack of evidence regarding the optimal imaging modality for this purpose. The present study aimed to compare the clinical outcomes of IHF patients undergoing cardiac magnetic resonance (CMR) versus positron emission tomography (PET) for myocardial viability assessment. Methods: We enrolled patients >18 years with IHF and ejection fraction (EF) < 45% needing viability assessment. Exclusions included those with cardiac devices, significant medical conditions, recent ST segment myocardial infarction (<4 weeks), unsuitability for revascularization, or needing emergency revascularization/valve surgery. Patients were randomized to PET or CMR for viability detection. The primary endpoint was the composite of cardiac death, myocardial infarction, cardiac arrest, or cardiac re-hospitalization. Secondary endpoints evaluated the effect of imaging strategies on each composite component, including cardiac death. Results: Total of 116 patients were randomized to either the CMR group (n=60) or the PET group (n=56) at sites where both modalities were available. There were no significant differences between the CMR and PET groups in terms of average age (63.7±9.6 vs. 63.9±10.2), prevalence of male patients (90% vs. 89%), or NYHA class III or IV (40% vs. 38%). The mean EF was 25.5±7.9 in the CMR and 26.6±8.3 in the PET group, with a standardized difference of 0.264.Over a median (IQR) of 25.0 (15.3,29.6) months, the cumulative incidence rate (CIR) for the primary endpoint was 25.0% for CMR and 32.6% for PET (HR 0.74,CI 0.37-1.49,p=0.402).The CIR for cardiac death was 13.9% for CMR vs. 13.2% for PET (HR 1.12 (0.41,3.06,p=0.822)).(Fig.1) Conclusion: The result of this randomized cohort showed that among IHF patients who required a definition of viability, there were no significant differences in the incidence of important cardiac endpoints when either CMR or PET were used. Larger randomized clinical trials should be considered to confirm the current results.