Clinical value and severity of myocardiardial perfusion defects in asymptomatic diabetic patients with negative or weakly positive exercise treadmill test

Introduction: Although coronary artery disease (CAD) is the leading cause of death in type 2 diabetic patients, it is frequently asymptomatic. Myocardial perfusion imaging (MPI) is reported to show ischemia in a significant number of asymptomatic diabetic patients. We studied the prevalence and severity of myocardial perfusion defects in asymptomatic diabetic patients and its clinical impact. Methods: One hundred thirty consecutive asymptomatic patients (81 female, 49 male), aged 35-65 years with type 2 diabetes mellitus and with no history of CAD and no cardiac symptoms were recruited in the study. Echocardiography, ECG, routine laboratory tests and exercise treadmill test (ETT) were performed and patients with weakly positive or negative ETT underwent Dipyridamole MPI. Patients with positive ETT were referred to coronary angiography. All patients were followed for at least 17 months (mean 21.7 months) and any cardiac event was recorded. Results: We studied 81 female and 49 male patients with mean age of 51.8 years. Negative and positive ETT result was noted in 74.3% and 10.7% respectively. One third of patients with positive ETT agreed to undergo coronary angiography which showed CAD in 75% of these patients. Gated myocardial perfusion SPECT showed reversible defect in 26.9% of the patients with mean summed stress score of 3.3±1.8. About 87% of the patients completed follow up and only one patient with abnormal MPI underwent coronary angiography followed by PTCA. No cardiac death, MI, UA or cardiac admission occurred among our patients during follow up. Conclusion: Reversible defects are commonly seen in myocardial perfusion SPECT in asymptomatic diabetic patients and are mild in severity and not associated with adverse cardiac events. Routine approach beginning with ETT seems to be appropriate in these patients.