Prognostic Value of Automatic Phase Analysis for Predicting Adverse Cardiac Events beyond Conventional SPECT Variables: Results from the REFINE SPECT

27 Introduction: Phase analysis of single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) provides dyssynchrony information which correlates well with assessments by echocardiography, but its independent prognostic significance is not well defined. This study assessed the independent prognostic value of SPECT-MPI phase analysis over conventional quantitative variables in the largest multinational registry to date across all modalities. Methods: From the REgistry of Fast Myocardial Perfusion Imaging with NExt generation SPECT (REFINE SPECT), a total of 19,210 patients were included (mean age 63.8 ± 12.0 years and 56% males). Post-stress total perfusion deficit (TPD), left ventricular ejection fraction (LVEF), and phase variables (phase entropy, bandwidth, and standard deviation) were obtained automatically. Cox proportional hazards analyses were performed to assess associations with major adverse cardiac events (MACE). Results: During a follow-up of 4.5 ± 1.7 years, 2673 (13.9%) patients experienced MACE. Annualized MACE rates increased with phase variables and were approximately 3.6-fold higher between the lowest and highest decile group for entropy (1.8% vs. 6.7%). Optimal cut-off values for all phase variables stratified MACE risk in patients with normal and abnormal TPD and LVEF. All phase variables remained independently associated with MACE in the adjusted Cox analyses. The addition of phase variables significantly improved the discriminatory power for MACE prediction when added to a model with TPD and LVEF (p