Use of dobutamine stress echocardiography in detecting silent myocardial ischaemia in asymptomatic diabetic patients: a comparison with thallium scintigraphy and exercise testing

Aims Silent myocardial ischaemia is frequent in diabetic patients. The aim of this study, was to compare the efficacy of thallium-20 I single-photon emission Computed tomograph (Tl-201 SPECT) coupled with exercise stress testing (EST), and dobutamine stress echocardiography (DSE) in the detection of asymptomatic coronary artery disease. Methods Fifty-six asymptomatic diabetic patients, with a known duration of diabetes >15 years for Type 1 and >5 years for Type 2, having at least three added risk factors, but without rest ECG abnormalities, were enrolled in this prospective study. All of them were submitted to DSE with a maximum infusion rate of 40 mug/kg per min dobutamine +/- i.v. atropine, and to Tl-201 SPECT coupled with EST. Coronary angiography was performed if at least one test was abnormal. Results Diabetic patients were 37 males and 19 females, aged mean (SD) 60 +/- 10 years, 10 Type 1 and 46 Type 2, with a known duration of disease of mean (SID) 17 +/- 9 years. Feasibility of DSE was 91%. No serious complication occurred during the test. Coronary angiography was performed in 26 patients (47%), 17 were abnormal (30% of the whole group): six patients had a one-vessel, six a two-vessel and five a three-vessel disease. Predictive positive value was 69%. for DSE, 75% for Tl-201 SPECT and 60% for EST. DSE was falsely negative in four cases vs. eight for Tl-201 SPECT and nine for EST. Conclusions Asymptomatic coronary disease is common in diabetes associated with other risk factors. DSE appears useful in its detection and a good alternative to Tl-201 SPECT.