What is the prognostic value of myocardial perfusion imaging using rubidium-82 positron emission tomography?

OBJECTIVES The objective was to determine the prognostic value of rubidium-82 (Rb-82) positron emission tomography (PET) myocardial perfusion imaging (MPI). BACKGROUND Rb-82 PET MPI accurately diagnoses coronary artery disease (CAD). However, there are limited data evaluating its prognostic value. METHODS Follow-up (3.1 +/- 0.9 years) was obtained in 367 patients who underwent dipyridamole Rb-82 PET MPI. Patients were divided into groups based on their summed stress score (SSS): group I, normal (< 4); group II, mild (4 to 7); and group III, moderate (8 to 11) to severe (>= 12). RESULTS There were significant differences among patients in the 3 SSS groups for hard events (cardiac death and myocardial infarction [MI]) (p < 0.001) and total cardiac events (hard events, revascularization and hospitalization) (p < 0.001). The annual hard events rates were 0.4%, 2.3%, and 7.0% in the normal, mild, and moderate-severe groups, respectively. In adjusted survival models, 12 Rb PET SSS was the strongest predictor of total cardiac events and a significant predictor of hard events. Among patients referred for PET after Tc-99m single-photon emission computed tomography, the annual total event rate was higher with abnormal versus normal SSS on PET (15.2% vs. 1.3%, p < 0.001). In patients with obesity, the annual total event rate was 11.1% with an abnormal scan and 1.5% with a normal scan (p < 0.001). CONCLUSIONS This study shows that Rb-82 PET MPI has significant prognostic value for predicting cardiac events, including death and MI. It also seems to have prognostic value in patients whose diagnosis remains uncertain after single-photon emission computed tomography MPI and in obese patients. The prognostic value of PET MPI may improve the management of cardiac patients.