Myocardial perfusion imaging in diabetes mellitus.

Although myocardial perfusion imaging is an established, noninvasive method for assessing risk in patients with suspected or known coronary artery disease, its usefulness in assessing the asymptomatic patient with diabetes mellitus has not been established. In the published literature, 16% to 56% of asymptomatic diabetes mellitus patients have stress myocardial perfusion-induced abnormalities. In prospective, unbiased populations, the prevalence of perfusion abnormalities are between 15% and 30%. The prognostic value of perfusion imaging in asymptomatic diabetes mellitus has been demonstrated. In diabetic patients with a normal perfusion scan, the yearly cardiac event rate is 1.2% to 2%, compared with 1% in the nondiabetic population. In patients with an abnormal myocardial perfusion scan, the cardiac event risk is increased three- to eightfold compared with patients with a normal scan. The severity of the perfusion abnormality is related to outcome. Prospective, randomized studies are required to demonstrate the efficacy of a strategy of stress myocardial perfusion imaging in asymptomatic diabetes mellitus patients.