Assessing the Prevalence and Predicting Factors of an Abnormal Gated Myocardial Perfusion SPECT in Asymptomatic Patients with Type 2 Diabetes

Abstract

Introduction: Considering the significant prevalence of silent myocardial ischemia and its related morbidity and mortality in asymptomatic type two diabetic patients, it is not well known whether early screening with MPI is cost-effective. However, predicting factors are not elucidated. Materials and Methods: This was a cross-sectional study including 63 asymptomatic patients with type 2 diabetes mellitus (T2DM), with normal ECG and ejection fraction. Patients with any history of documented valvular, congestive or ischemic heart disease, renal or hepatic failure were excluded. At first all patients were interviewed and checked for risk factors and then patients underwent a two-day rest/stress 99mTc-MIBI gated MPI SPECT. Data was assessed by QPS/QGS and 4DM software and evaluated by a nuclear medicine specialist with summed stress score (SSS) of more than 4 defined as CAD. Results: There were 42 females (67%) and 21 males (33%), with a mean age of 61.33 ± 6.98 years and 7.97 ± 4.86 years history of T2DM. CAD was detected in 26 (41.3%) patients and was significantly associated with male gender, smoking, requiring insulin therapy and EF (P-value = 0.019, 0.046, 0.05, 0.033, respectively). A significant association was found between the duration of diabetes, especially when >15y, and the probability of having CAD.. Multivariable logistic regression revealed that smoking; male gender and diabetes duration were the strongest independent predictors of abnormal MPI results. Conclusion: We found a high (46%) prevalence of abnormal stress MPI SPECT in patients with type 2 diabetes mellitus, despite being asymptomatic. Asymptomatic patients with a history of smoking, long duration of diabetes, being under insulin treatment and male gender might benefit from MPI for early detection of silent ischemia. Keyword: 99mTc-MIBI; Gated Myocardial Perfusion Imaging; Type 2 Diabetes Mellitus; Silent Ischemia; Asymptomatic CAD; Early Screening