Association of ischemia on stress ^99mTc-tetrofosmin myocardial perfusion imaging with all-cause mortality in patients with diabetes mellitus

Stress myocardial perfusion imaging is a useful method for evaluation of coronary artery disease (CAD) in patients with diabetes mellitus. However, its role in predicting all-cause mortality is not well defined. The aim of this study was to determine whether myocardial ischemia on stress myocardial perfusion imaging can predict all causes of death in patients with diabetes mellitus. Methods: We studied 297 patients with diabetes mellitus and known or suspected CAD by exercise or dobutamine stress ^99mTc-tetrofosmin myocardial perfusion tomographic imaging. Ischemia was defined as reversible perfusion abnormalities. The endpoints were death from any cause and hard cardiac events (cardiac death and nonfatal myocardial infarction). Results: An abnormal scan was detected in 179 (60%) patients. Myocardial perfusion abnormalities were fixed in 76 (26%) patients and were reversible in 103 (35%) patients. During a mean follow-up of 6 ± 2.1 y, 80 (27%) patients died. Nonfatal myocardial infarction occurred in 14 (5%) patients. The annual mortality rate was 2.5% in patients with normal perfusion, 4.5% in patients with fixed defects, and 6% in patients with ischemia. The annual cardiac death rate was 4.2% in patients with ischemia and 2.6% in patients with fixed defects. In patients with normal perfusion, the annual cardiac death rate was 0.9% during the 5 y after the stress test. In a Cox multivariate analysis model, predictors of death were age, history of heart failure, peripheral vascular disease, and reversible perfusion defects. Conclusion: Myocardial ischemia on stress ^99mTc-tetrofosmin myocardial perfusion imaging is associated with an increased risk of all-cause mortality during long-term follow-up among patients with diabetes mellitus. Patients with normal perfusion have a lower mortality rate and may require less frequent follow-up stress perfusion imaging.