Comparative Predictors of Mortality among Patients Referred for Stress SPECT versus PET Myocardial Perfusion Imaging.

BACKGROUND: There is currently little information regarding the usage and comparative predictors of mortality among patients referred for SPECT versus PET myocardial perfusion imaging (MPI) within multimodality imaging laboratories.

METHODS: We compared the clinical characteristics and mortality outcomes among 15,718 patients referred for SPECT-MPI and 6,202 patients referred for PET-MPI between 2008-2017.

RESULTS: Approximately two-thirds of MPI studies were performed using SPECT-MPI. The PET-MPI group was substantially older and included more patients with known CAD, hypertension, diabetes, and myocardial ischemia. The annualized mortality rate was also higher in the PET-MPI group and this difference persisted after propensity matching 3,615 SPECT-MPI and 3,615 PET-MPI patients to have similar clinical profiles. Among the SPECT-MPI patients, the most potent predictor of mortality was exercise ability and performance, including consideration of patients' mode of stress testing and exercise duration. Among the PET-MPI patients, myocardial flow reserve (MFR) was the most potent predictor of mortality.

CONCLUSIONS: In our real-world setting, PET-MPI was more commonly employed among older patients with more cardiac risk factors than SPECT-MPI patients. The most potent predictors of mortality in our SPECT and PET-MPI groups were variables exclusive for each test: exercise ability/capacity for SPECT-MPI patients and MFR for PET-MPI patients.