Correlation between myocardial perfusion imaging findings and future cardiac events in patients with type 2 diabetes mellitus

Introduction/Objective. Myocardial perfusion imaging (MPI) is clinically useful for the evaluation of coronary artery disease (CAD) in patients with diabetes mellitus (DM). However, the prevalence of ischemia and its ability to predict future cardiac events is less clear. The aim was to determine the incidence of cardiac events in diabetic patients and relationship between them and MPI findings. Methods. Two cohorts of patients, 98 diabetics and 100 non-diabetics, with medium- to high-risk of CAD without previous coronary revascularization were studied prospectively. All of them were outpatients underwent 99mTc-sestamibi MPI with dipyridamole. The data about cardiac events were collected during follow-up period of two years. Results. Cardiac events occurred in 17.3% diabetics and in 8% non-diabetics (p = 0.048). Diabetics had shorter estimated event-free time 24.7 months (95% CI 23.2-26.2) versus non-diabetics 28.5 months (95% CI 27.4-29.5) (p = 0.046). The independent predictors of cardiac events were male sex (p = 0.010), previous myocardial infarction (p < 0.001), presence of the symptoms of angina (p = 0.014) and all variables derived from MPI findings. After adjustment for variables derived from MPI findings, the significant predictors in diabetics were size of stress perfusion defect (p = 0.022), summed stress score (p = 0.011) and summed difference score (p = 0.044). Conclusion. In diabetic patients, the cumulative rate of cardiac events was higher and the event-free survival was worse. MPI could help in prediction of cardiac events in diabetics and the most important predictors were size of stress perfusion defect, summed stress score and summed difference score.