Prognostic Value of Simultaneous Analysis with Myocardial Flow Reserve and Right Ventricular Strain by Hybrid 13N-Ammonia Positron Emission Tomography/Magnetic Resonance Imaging in Coronary Artery Disease

Myocardial flow reserve (MFR) derived from N-13-ammonia positron emission tomography (PET) is used to predict adverse cardiac events in patients with coronary artery disease (CAD). Right ventricular global longitudinal strain (RVGLS) measured by magnetic resonance imaging (MRI) is used to evaluate RV function and predict cardiac events. This study aimed to evaluate the prognostic value of MFR and RVGLS measured by hybrid N-13-ammonia PET/MRI in patients with CAD. Sixty-one patients who underwent N-13-ammonia PET/MRI were analyzed. The end points were defined as a composite of all-cause death, myocardial infarction, sustained ventricular arrhythmia, hospitalization due to decompensated heart failure, and revascularization. At a follow-up of 2.8 +/- 1.9 years, 21 events had occurred. Kaplan-Meier analysis showed that the event-free rate was significantly lower in the group with MFR < 1.80 than in that with MFR >= 1.80 (P < 0.001). Additionally, the event-free rate was significantly lower in the group with RVGLS > -18.22% than in that with RVGLS <= -18.22% (P = 0.025). After dividing the patients into 4 groups by the median MFR and the median RVGLS, the event-free rate was lowest in the combined group of MFR < 1.80 and RVGLS > -18.22% than any other groups (P < 0.001). In a Cox proportional hazard analysis, MFR and RVGLS were independent predictors of cardiac adverse events in the patients with CAD. The simultaneous assessment of MFR and RVGLS by N-13-ammonia PET/MRI revealed the feasibility of precise risk stratification for cardiac events in patients with CAD.