Effective Early Screening Modalities for Asymptomatic Coronary Artery Disease in Patients with Type 2 Diabetes Mellitus

Background: Coronary artery disease (CAD) is often asymptomatic in type 2 diabetes mellitus (DM) patients until the onset of myocardial infarction (MI) or sudden cardiac death. The aim of this study was to evaluate the effective early screening modalities for asymptomatic CAD in patients with DM at a tertiary care hospital. Methods and Materials: Patients aged ≥ 40 years with DM of at least 5 years duration were included in the study. Patients underwent all routine investigations to detect additional risk factors of diabetes followed by sequential screening using echocardiography (echo), treadmill exercise ECG or NH3-stress PET. Results: There were 39 men and 45 women with a mean age of 57.7 ± 8.2 years. The mean duration of diabetes was 9.3 ± 3.2 years and the mean HbA1c level was 7.98 ± 1.18 %. The sensitivity and specificity of echo was 15.4% and 94.4% respectively. Treadmill exercise ECG had a sensitivity of 73% and specificity of 35.3%. For NH3-stress PET with reversible perfusion defect (RPD) > 10%, the sensitivity and specificity of finding significant lesion on coronary angiography (CAG) was 100% and 83.3% respectively. Among various traditional risk factors for developing CAD, there was a strong statistical significance with hypertension, dyslipidemia and albuminuria (p < 0.05). Conclusion: Early screening for asymptomatic CAD among patients with DM is recommended especially for those who have DM of at least 5 years duration or have additional risk factors. Considering the cost and availability, treadmill exercise ECG should be considered as initial screening test followed by stratification with Duke Treadmill Score (DTS).