Prognostic Value of Normal Exercise and Adenosine 99mTc-Tetrofosmin SPECT Imaging: Results from the Multicenter Registry of 4,728 Patients

Event rates associated with a normal or low-risk myocardial perfusion SPECT imaging study have been shown by numerous investigators to be associated with <1 %/y of follow-up. Thus, the aim of this study was to evaluate the prognostic value of a normal 99m Tc-tetrofosmin study in a geographically diverse registry of patients undergoing stress myocardial perfusion SPECT. A total of 4,728 consecutively tested patients who underwent stress 99m Tc-tetrofosmin SPECT at 5 U.S. hospitals were included in this series. Methods: Patients were monitored for the occurrence of major cardiac events and hospitalizations. Uniform methods of data collection and standardized epidemiologic methods for follow-up were used at all centers. We used a risk-adjusted, Cox proportional hazards model to assess time to cardiac death. Results: Of the 4,728 patients, one third underwent adenosine stress SPECT and two thirds underwent treadmill exercise. The observed annualized survival rate for those patients with a normal 99m Tc-tetrofosmin study was 0.6%. Similarly, excellent survival rates were noted for the male and female subsets of this population as well as for patients who could exercise and for those undergoing pharmacologic stress testing. Compared with prior published outcomes studies on stress 201 Tl or 99m Tc-sestamibi SPECT, the overall survival rates were similar and ranged from 99.3% to 99.7%. Conclusion: Results from this large multicenter registry provide further supportive evidence that the excellent prognosis associated with a normal SPECT scan is independent of the radiopharmaceutical used.